fs/btrfs/extent-tree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/sched/signal.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/writeback.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/sort.h>
  12 #include <linux/rcupdate.h>
  13 #include <linux/kthread.h>
  14 #include <linux/slab.h>
  15 #include <linux/ratelimit.h>
  16 #include <linux/percpu_counter.h>
  17 #include <linux/lockdep.h>
  18 #include <linux/crc32c.h>
  19 #include "tree-log.h"
  20 #include "disk-io.h"
  21 #include "print-tree.h"
  22 #include "volumes.h"
  23 #include "raid56.h"
  24 #include "locking.h"
  25 #include "free-space-cache.h"
  26 #include "free-space-tree.h"
  27 #include "math.h"
  28 #include "sysfs.h"
  29 #include "qgroup.h"
  30 #include "ref-verify.h"
  31
  32 #undef SCRAMBLE_DELAYED_REFS
  33
  34 /*
  35  * control flags for do_chunk_alloc's force field
  36  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  37  * if we really need one.
  38  *
  39  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  40  * if we have very few chunks already allocated.  This is
  41  * used as part of the clustering code to help make sure
  42  * we have a good pool of storage to cluster in, without
  43  * filling the FS with empty chunks
  44  *
  45  * CHUNK_ALLOC_FORCE means it must try to allocate one
  46  *
  47  */
  48 enum {
  49         CHUNK_ALLOC_NO_FORCE = 0,
  50         CHUNK_ALLOC_LIMITED = 1,
  51         CHUNK_ALLOC_FORCE = 2,
  52 };
  53
  54 /*
  55  * Declare a helper function to detect underflow of various space info members
  56  */
  57 #define DECLARE_SPACE_INFO_UPDATE(name)                                 \
  58 static inline void update_##name(struct btrfs_space_info *sinfo,        \
  59                                  s64 bytes)                             \
  60 {                                                                       \
  61         if (bytes < 0 && sinfo->name < -bytes) {                        \
  62                 WARN_ON(1);                                             \
  63                 sinfo->name = 0;                                        \
  64                 return;                                                 \
  65         }                                                               \
  66         sinfo->name += bytes;                                           \
  67 }
  68
  69 DECLARE_SPACE_INFO_UPDATE(bytes_may_use);
  70 DECLARE_SPACE_INFO_UPDATE(bytes_pinned);
  71
  72 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  73                                struct btrfs_delayed_ref_node *node, u64 parent,
  74                                u64 root_objectid, u64 owner_objectid,
  75                                u64 owner_offset, int refs_to_drop,
  76                                struct btrfs_delayed_extent_op *extra_op);
  77 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  78                                     struct extent_buffer *leaf,
  79                                     struct btrfs_extent_item *ei);
  80 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  81                                       u64 parent, u64 root_objectid,
  82                                       u64 flags, u64 owner, u64 offset,
  83                                       struct btrfs_key *ins, int ref_mod);
  84 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  85                                      struct btrfs_delayed_ref_node *node,
  86                                      struct btrfs_delayed_extent_op *extent_op);
  87 static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
  88                           int force);
  89 static int find_next_key(struct btrfs_path *path, int level,
  90                          struct btrfs_key *key);
  91 static void dump_space_info(struct btrfs_fs_info *fs_info,
  92                             struct btrfs_space_info *info, u64 bytes,
  93                             int dump_block_groups);
  94 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
  95                                u64 num_bytes);
  96 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
  97                                      struct btrfs_space_info *space_info,
  98                                      u64 num_bytes);
  99 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
 100                                      struct btrfs_space_info *space_info,
 101                                      u64 num_bytes);
 102
 103 static noinline int
 104 block_group_cache_done(struct btrfs_block_group_cache *cache)
 105 {
 106         smp_mb();
 107         return cache->cached == BTRFS_CACHE_FINISHED ||
 108                 cache->cached == BTRFS_CACHE_ERROR;
 109 }
 110
 111 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 112 {
 113         return (cache->flags & bits) == bits;
 114 }
 115
 116 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 117 {
 118         atomic_inc(&cache->count);
 119 }
 120
 121 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 122 {
 123         if (atomic_dec_and_test(&cache->count)) {
 124                 WARN_ON(cache->pinned > 0);
 125                 WARN_ON(cache->reserved > 0);
 126
 127                 /*
 128                  * If not empty, someone is still holding mutex of
 129                  * full_stripe_lock, which can only be released by caller.
 130                  * And it will definitely cause use-after-free when caller
 131                  * tries to release full stripe lock.
 132                  *
 133                  * No better way to resolve, but only to warn.
 134                  */
 135                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 136                 kfree(cache->free_space_ctl);
 137                 kfree(cache);
 138         }
 139 }
 140
 141 /*
 142  * this adds the block group to the fs_info rb tree for the block group
 143  * cache
 144  */
 145 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 146                                 struct btrfs_block_group_cache *block_group)
 147 {
 148         struct rb_node **p;
 149         struct rb_node *parent = NULL;
 150         struct btrfs_block_group_cache *cache;
 151
 152         spin_lock(&info->block_group_cache_lock);
 153         p = &info->block_group_cache_tree.rb_node;
 154
 155         while (*p) {
 156                 parent = *p;
 157                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 158                                  cache_node);
 159                 if (block_group->key.objectid < cache->key.objectid) {
 160                         p = &(*p)->rb_left;
 161                 } else if (block_group->key.objectid > cache->key.objectid) {
 162                         p = &(*p)->rb_right;
 163                 } else {
 164                         spin_unlock(&info->block_group_cache_lock);
 165                         return -EEXIST;
 166                 }
 167         }
 168
 169         rb_link_node(&block_group->cache_node, parent, p);
 170         rb_insert_color(&block_group->cache_node,
 171                         &info->block_group_cache_tree);
 172
 173         if (info->first_logical_byte > block_group->key.objectid)
 174                 info->first_logical_byte = block_group->key.objectid;
 175
 176         spin_unlock(&info->block_group_cache_lock);
 177
 178         return 0;
 179 }
 180
 181 /*
 182  * This will return the block group at or after bytenr if contains is 0, else
 183  * it will return the block group that contains the bytenr
 184  */
 185 static struct btrfs_block_group_cache *
 186 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 187                               int contains)
 188 {
 189         struct btrfs_block_group_cache *cache, *ret = NULL;
 190         struct rb_node *n;
 191         u64 end, start;
 192
 193         spin_lock(&info->block_group_cache_lock);
 194         n = info->block_group_cache_tree.rb_node;
 195
 196         while (n) {
 197                 cache = rb_entry(n, struct btrfs_block_group_cache,
 198                                  cache_node);
 199                 end = cache->key.objectid + cache->key.offset - 1;
 200                 start = cache->key.objectid;
 201
 202                 if (bytenr < start) {
 203                         if (!contains && (!ret || start < ret->key.objectid))
 204                                 ret = cache;
 205                         n = n->rb_left;
 206                 } else if (bytenr > start) {
 207                         if (contains && bytenr <= end) {
 208                                 ret = cache;
 209                                 break;
 210                         }
 211                         n = n->rb_right;
 212                 } else {
 213                         ret = cache;
 214                         break;
 215                 }
 216         }
 217         if (ret) {
 218                 btrfs_get_block_group(ret);
 219                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 220                         info->first_logical_byte = ret->key.objectid;
 221         }
 222         spin_unlock(&info->block_group_cache_lock);
 223
 224         return ret;
 225 }
 226
 227 static int add_excluded_extent(struct btrfs_fs_info *fs_info,
 228                                u64 start, u64 num_bytes)
 229 {
 230         u64 end = start + num_bytes - 1;
 231         set_extent_bits(&fs_info->freed_extents[0],
 232                         start, end, EXTENT_UPTODATE);
 233         set_extent_bits(&fs_info->freed_extents[1],
 234                         start, end, EXTENT_UPTODATE);
 235         return 0;
 236 }
 237
 238 static void free_excluded_extents(struct btrfs_block_group_cache *cache)
 239 {
 240         struct btrfs_fs_info *fs_info = cache->fs_info;
 241         u64 start, end;
 242
 243         start = cache->key.objectid;
 244         end = start + cache->key.offset - 1;
 245
 246         clear_extent_bits(&fs_info->freed_extents[0],
 247                           start, end, EXTENT_UPTODATE);
 248         clear_extent_bits(&fs_info->freed_extents[1],
 249                           start, end, EXTENT_UPTODATE);
 250 }
 251
 252 static int exclude_super_stripes(struct btrfs_block_group_cache *cache)
 253 {
 254         struct btrfs_fs_info *fs_info = cache->fs_info;
 255         u64 bytenr;
 256         u64 *logical;
 257         int stripe_len;
 258         int i, nr, ret;
 259
 260         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 261                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 262                 cache->bytes_super += stripe_len;
 263                 ret = add_excluded_extent(fs_info, cache->key.objectid,
 264                                           stripe_len);
 265                 if (ret)
 266                         return ret;
 267         }
 268
 269         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 270                 bytenr = btrfs_sb_offset(i);
 271                 ret = btrfs_rmap_block(fs_info, cache->key.objectid,
 272                                        bytenr, &logical, &nr, &stripe_len);
 273                 if (ret)
 274                         return ret;
 275
 276                 while (nr--) {
 277                         u64 start, len;
 278
 279                         if (logical[nr] > cache->key.objectid +
 280                             cache->key.offset)
 281                                 continue;
 282
 283                         if (logical[nr] + stripe_len <= cache->key.objectid)
 284                                 continue;
 285
 286                         start = logical[nr];
 287                         if (start < cache->key.objectid) {
 288                                 start = cache->key.objectid;
 289                                 len = (logical[nr] + stripe_len) - start;
 290                         } else {
 291                                 len = min_t(u64, stripe_len,
 292                                             cache->key.objectid +
 293                                             cache->key.offset - start);
 294                         }
 295
 296                         cache->bytes_super += len;
 297                         ret = add_excluded_extent(fs_info, start, len);
 298                         if (ret) {
 299                                 kfree(logical);
 300                                 return ret;
 301                         }
 302                 }
 303
 304                 kfree(logical);
 305         }
 306         return 0;
 307 }
 308
 309 static struct btrfs_caching_control *
 310 get_caching_control(struct btrfs_block_group_cache *cache)
 311 {
 312         struct btrfs_caching_control *ctl;
 313
 314         spin_lock(&cache->lock);
 315         if (!cache->caching_ctl) {
 316                 spin_unlock(&cache->lock);
 317                 return NULL;
 318         }
 319
 320         ctl = cache->caching_ctl;
 321         refcount_inc(&ctl->count);
 322         spin_unlock(&cache->lock);
 323         return ctl;
 324 }
 325
 326 static void put_caching_control(struct btrfs_caching_control *ctl)
 327 {
 328         if (refcount_dec_and_test(&ctl->count))
 329                 kfree(ctl);
 330 }
 331
 332 #ifdef CONFIG_BTRFS_DEBUG
 333 static void fragment_free_space(struct btrfs_block_group_cache *block_group)
 334 {
 335         struct btrfs_fs_info *fs_info = block_group->fs_info;
 336         u64 start = block_group->key.objectid;
 337         u64 len = block_group->key.offset;
 338         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 339                 fs_info->nodesize : fs_info->sectorsize;
 340         u64 step = chunk << 1;
 341
 342         while (len > chunk) {
 343                 btrfs_remove_free_space(block_group, start, chunk);
 344                 start += step;
 345                 if (len < step)
 346                         len = 0;
 347                 else
 348                         len -= step;
 349         }
 350 }
 351 #endif
 352
 353 /*
 354  * this is only called by cache_block_group, since we could have freed extents
 355  * we need to check the pinned_extents for any extents that can't be used yet
 356  * since their free space will be released as soon as the transaction commits.
 357  */
 358 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 359                        u64 start, u64 end)
 360 {
 361         struct btrfs_fs_info *info = block_group->fs_info;
 362         u64 extent_start, extent_end, size, total_added = 0;
 363         int ret;
 364
 365         while (start < end) {
 366                 ret = find_first_extent_bit(info->pinned_extents, start,
 367                                             &extent_start, &extent_end,
 368                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 369                                             NULL);
 370                 if (ret)
 371                         break;
 372
 373                 if (extent_start <= start) {
 374                         start = extent_end + 1;
 375                 } else if (extent_start > start && extent_start < end) {
 376                         size = extent_start - start;
 377                         total_added += size;
 378                         ret = btrfs_add_free_space(block_group, start,
 379                                                    size);
 380                         BUG_ON(ret); /* -ENOMEM or logic error */
 381                         start = extent_end + 1;
 382                 } else {
 383                         break;
 384                 }
 385         }
 386
 387         if (start < end) {
 388                 size = end - start;
 389                 total_added += size;
 390                 ret = btrfs_add_free_space(block_group, start, size);
 391                 BUG_ON(ret); /* -ENOMEM or logic error */
 392         }
 393
 394         return total_added;
 395 }
 396
 397 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 398 {
 399         struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
 400         struct btrfs_fs_info *fs_info = block_group->fs_info;
 401         struct btrfs_root *extent_root = fs_info->extent_root;
 402         struct btrfs_path *path;
 403         struct extent_buffer *leaf;
 404         struct btrfs_key key;
 405         u64 total_found = 0;
 406         u64 last = 0;
 407         u32 nritems;
 408         int ret;
 409         bool wakeup = true;
 410
 411         path = btrfs_alloc_path();
 412         if (!path)
 413                 return -ENOMEM;
 414
 415         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 416
 417 #ifdef CONFIG_BTRFS_DEBUG
 418         /*
 419          * If we're fragmenting we don't want to make anybody think we can
 420          * allocate from this block group until we've had a chance to fragment
 421          * the free space.
 422          */
 423         if (btrfs_should_fragment_free_space(block_group))
 424                 wakeup = false;
 425 #endif
 426         /*
 427          * We don't want to deadlock with somebody trying to allocate a new
 428          * extent for the extent root while also trying to search the extent
 429          * root to add free space.  So we skip locking and search the commit
 430          * root, since its read-only
 431          */
 432         path->skip_locking = 1;
 433         path->search_commit_root = 1;
 434         path->reada = READA_FORWARD;
 435
 436         key.objectid = last;
 437         key.offset = 0;
 438         key.type = BTRFS_EXTENT_ITEM_KEY;
 439
 440 next:
 441         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 442         if (ret < 0)
 443                 goto out;
 444
 445         leaf = path->nodes[0];
 446         nritems = btrfs_header_nritems(leaf);
 447
 448         while (1) {
 449                 if (btrfs_fs_closing(fs_info) > 1) {
 450                         last = (u64)-1;
 451                         break;
 452                 }
 453
 454                 if (path->slots[0] < nritems) {
 455                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 456                 } else {
 457                         ret = find_next_key(path, 0, &key);
 458                         if (ret)
 459                                 break;
 460
 461                         if (need_resched() ||
 462                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 463                                 if (wakeup)
 464                                         caching_ctl->progress = last;
 465                                 btrfs_release_path(path);
 466                                 up_read(&fs_info->commit_root_sem);
 467                                 mutex_unlock(&caching_ctl->mutex);
 468                                 cond_resched();
 469                                 mutex_lock(&caching_ctl->mutex);
 470                                 down_read(&fs_info->commit_root_sem);
 471                                 goto next;
 472                         }
 473
 474                         ret = btrfs_next_leaf(extent_root, path);
 475                         if (ret < 0)
 476                                 goto out;
 477                         if (ret)
 478                                 break;
 479                         leaf = path->nodes[0];
 480                         nritems = btrfs_header_nritems(leaf);
 481                         continue;
 482                 }
 483
 484                 if (key.objectid < last) {
 485                         key.objectid = last;
 486                         key.offset = 0;
 487                         key.type = BTRFS_EXTENT_ITEM_KEY;
 488
 489                         if (wakeup)
 490                                 caching_ctl->progress = last;
 491                         btrfs_release_path(path);
 492                         goto next;
 493                 }
 494
 495                 if (key.objectid < block_group->key.objectid) {
 496                         path->slots[0]++;
 497                         continue;
 498                 }
 499
 500                 if (key.objectid >= block_group->key.objectid +
 501                     block_group->key.offset)
 502                         break;
 503
 504                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 505                     key.type == BTRFS_METADATA_ITEM_KEY) {
 506                         total_found += add_new_free_space(block_group, last,
 507                                                           key.objectid);
 508                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 509                                 last = key.objectid +
 510                                         fs_info->nodesize;
 511                         else
 512                                 last = key.objectid + key.offset;
 513
 514                         if (total_found > CACHING_CTL_WAKE_UP) {
 515                                 total_found = 0;
 516                                 if (wakeup)
 517                                         wake_up(&caching_ctl->wait);
 518                         }
 519                 }
 520                 path->slots[0]++;
 521         }
 522         ret = 0;
 523
 524         total_found += add_new_free_space(block_group, last,
 525                                           block_group->key.objectid +
 526                                           block_group->key.offset);
 527         caching_ctl->progress = (u64)-1;
 528
 529 out:
 530         btrfs_free_path(path);
 531         return ret;
 532 }
 533
 534 static noinline void caching_thread(struct btrfs_work *work)
 535 {
 536         struct btrfs_block_group_cache *block_group;
 537         struct btrfs_fs_info *fs_info;
 538         struct btrfs_caching_control *caching_ctl;
 539         int ret;
 540
 541         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 542         block_group = caching_ctl->block_group;
 543         fs_info = block_group->fs_info;
 544
 545         mutex_lock(&caching_ctl->mutex);
 546         down_read(&fs_info->commit_root_sem);
 547
 548         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 549                 ret = load_free_space_tree(caching_ctl);
 550         else
 551                 ret = load_extent_tree_free(caching_ctl);
 552
 553         spin_lock(&block_group->lock);
 554         block_group->caching_ctl = NULL;
 555         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 556         spin_unlock(&block_group->lock);
 557
 558 #ifdef CONFIG_BTRFS_DEBUG
 559         if (btrfs_should_fragment_free_space(block_group)) {
 560                 u64 bytes_used;
 561
 562                 spin_lock(&block_group->space_info->lock);
 563                 spin_lock(&block_group->lock);
 564                 bytes_used = block_group->key.offset -
 565                         btrfs_block_group_used(&block_group->item);
 566                 block_group->space_info->bytes_used += bytes_used >> 1;
 567                 spin_unlock(&block_group->lock);
 568                 spin_unlock(&block_group->space_info->lock);
 569                 fragment_free_space(block_group);
 570         }
 571 #endif
 572
 573         caching_ctl->progress = (u64)-1;
 574
 575         up_read(&fs_info->commit_root_sem);
 576         free_excluded_extents(block_group);
 577         mutex_unlock(&caching_ctl->mutex);
 578
 579         wake_up(&caching_ctl->wait);
 580
 581         put_caching_control(caching_ctl);
 582         btrfs_put_block_group(block_group);
 583 }
 584
 585 static int cache_block_group(struct btrfs_block_group_cache *cache,
 586                              int load_cache_only)
 587 {
 588         DEFINE_WAIT(wait);
 589         struct btrfs_fs_info *fs_info = cache->fs_info;
 590         struct btrfs_caching_control *caching_ctl;
 591         int ret = 0;
 592
 593         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 594         if (!caching_ctl)
 595                 return -ENOMEM;
 596
 597         INIT_LIST_HEAD(&caching_ctl->list);
 598         mutex_init(&caching_ctl->mutex);
 599         init_waitqueue_head(&caching_ctl->wait);
 600         caching_ctl->block_group = cache;
 601         caching_ctl->progress = cache->key.objectid;
 602         refcount_set(&caching_ctl->count, 1);
 603         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 604                         caching_thread, NULL, NULL);
 605
 606         spin_lock(&cache->lock);
 607         /*
 608          * This should be a rare occasion, but this could happen I think in the
 609          * case where one thread starts to load the space cache info, and then
 610          * some other thread starts a transaction commit which tries to do an
 611          * allocation while the other thread is still loading the space cache
 612          * info.  The previous loop should have kept us from choosing this block
 613          * group, but if we've moved to the state where we will wait on caching
 614          * block groups we need to first check if we're doing a fast load here,
 615          * so we can wait for it to finish, otherwise we could end up allocating
 616          * from a block group who's cache gets evicted for one reason or
 617          * another.
 618          */
 619         while (cache->cached == BTRFS_CACHE_FAST) {
 620                 struct btrfs_caching_control *ctl;
 621
 622                 ctl = cache->caching_ctl;
 623                 refcount_inc(&ctl->count);
 624                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 625                 spin_unlock(&cache->lock);
 626
 627                 schedule();
 628
 629                 finish_wait(&ctl->wait, &wait);
 630                 put_caching_control(ctl);
 631                 spin_lock(&cache->lock);
 632         }
 633
 634         if (cache->cached != BTRFS_CACHE_NO) {
 635                 spin_unlock(&cache->lock);
 636                 kfree(caching_ctl);
 637                 return 0;
 638         }
 639         WARN_ON(cache->caching_ctl);
 640         cache->caching_ctl = caching_ctl;
 641         cache->cached = BTRFS_CACHE_FAST;
 642         spin_unlock(&cache->lock);
 643
 644         if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
 645                 mutex_lock(&caching_ctl->mutex);
 646                 ret = load_free_space_cache(fs_info, cache);
 647
 648                 spin_lock(&cache->lock);
 649                 if (ret == 1) {
 650                         cache->caching_ctl = NULL;
 651                         cache->cached = BTRFS_CACHE_FINISHED;
 652                         cache->last_byte_to_unpin = (u64)-1;
 653                         caching_ctl->progress = (u64)-1;
 654                 } else {
 655                         if (load_cache_only) {
 656                                 cache->caching_ctl = NULL;
 657                                 cache->cached = BTRFS_CACHE_NO;
 658                         } else {
 659                                 cache->cached = BTRFS_CACHE_STARTED;
 660                                 cache->has_caching_ctl = 1;
 661                         }
 662                 }
 663                 spin_unlock(&cache->lock);
 664 #ifdef CONFIG_BTRFS_DEBUG
 665                 if (ret == 1 &&
 666                     btrfs_should_fragment_free_space(cache)) {
 667                         u64 bytes_used;
 668
 669                         spin_lock(&cache->space_info->lock);
 670                         spin_lock(&cache->lock);
 671                         bytes_used = cache->key.offset -
 672                                 btrfs_block_group_used(&cache->item);
 673                         cache->space_info->bytes_used += bytes_used >> 1;
 674                         spin_unlock(&cache->lock);
 675                         spin_unlock(&cache->space_info->lock);
 676                         fragment_free_space(cache);
 677                 }
 678 #endif
 679                 mutex_unlock(&caching_ctl->mutex);
 680
 681                 wake_up(&caching_ctl->wait);
 682                 if (ret == 1) {
 683                         put_caching_control(caching_ctl);
 684                         free_excluded_extents(cache);
 685                         return 0;
 686                 }
 687         } else {
 688                 /*
 689                  * We're either using the free space tree or no caching at all.
 690                  * Set cached to the appropriate value and wakeup any waiters.
 691                  */
 692                 spin_lock(&cache->lock);
 693                 if (load_cache_only) {
 694                         cache->caching_ctl = NULL;
 695                         cache->cached = BTRFS_CACHE_NO;
 696                 } else {
 697                         cache->cached = BTRFS_CACHE_STARTED;
 698                         cache->has_caching_ctl = 1;
 699                 }
 700                 spin_unlock(&cache->lock);
 701                 wake_up(&caching_ctl->wait);
 702         }
 703
 704         if (load_cache_only) {
 705                 put_caching_control(caching_ctl);
 706                 return 0;
 707         }
 708
 709         down_write(&fs_info->commit_root_sem);
 710         refcount_inc(&caching_ctl->count);
 711         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 712         up_write(&fs_info->commit_root_sem);
 713
 714         btrfs_get_block_group(cache);
 715
 716         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 717
 718         return ret;
 719 }
 720
 721 /*
 722  * return the block group that starts at or after bytenr
 723  */
 724 static struct btrfs_block_group_cache *
 725 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 726 {
 727         return block_group_cache_tree_search(info, bytenr, 0);
 728 }
 729
 730 /*
 731  * return the block group that contains the given bytenr
 732  */
 733 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 734                                                  struct btrfs_fs_info *info,
 735                                                  u64 bytenr)
 736 {
 737         return block_group_cache_tree_search(info, bytenr, 1);
 738 }
 739
 740 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 741                                                   u64 flags)
 742 {
 743         struct list_head *head = &info->space_info;
 744         struct btrfs_space_info *found;
 745
 746         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 747
 748         rcu_read_lock();
 749         list_for_each_entry_rcu(found, head, list) {
 750                 if (found->flags & flags) {
 751                         rcu_read_unlock();
 752                         return found;
 753                 }
 754         }
 755         rcu_read_unlock();
 756         return NULL;
 757 }
 758
 759 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, s64 num_bytes,
 760                              bool metadata, u64 root_objectid)
 761 {
 762         struct btrfs_space_info *space_info;
 763         u64 flags;
 764
 765         if (metadata) {
 766                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
 767                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
 768                 else
 769                         flags = BTRFS_BLOCK_GROUP_METADATA;
 770         } else {
 771                 flags = BTRFS_BLOCK_GROUP_DATA;
 772         }
 773
 774         space_info = __find_space_info(fs_info, flags);
 775         ASSERT(space_info);
 776         percpu_counter_add_batch(&space_info->total_bytes_pinned, num_bytes,
 777                     BTRFS_TOTAL_BYTES_PINNED_BATCH);
 778 }
 779
 780 /*
 781  * after adding space to the filesystem, we need to clear the full flags
 782  * on all the space infos.
 783  */
 784 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 785 {
 786         struct list_head *head = &info->space_info;
 787         struct btrfs_space_info *found;
 788
 789         rcu_read_lock();
 790         list_for_each_entry_rcu(found, head, list)
 791                 found->full = 0;
 792         rcu_read_unlock();
 793 }
 794
 795 /* simple helper to search for an existing data extent at a given offset */
 796 int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
 797 {
 798         int ret;
 799         struct btrfs_key key;
 800         struct btrfs_path *path;
 801
 802         path = btrfs_alloc_path();
 803         if (!path)
 804                 return -ENOMEM;
 805
 806         key.objectid = start;
 807         key.offset = len;
 808         key.type = BTRFS_EXTENT_ITEM_KEY;
 809         ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 810         btrfs_free_path(path);
 811         return ret;
 812 }
 813
 814 /*
 815  * helper function to lookup reference count and flags of a tree block.
 816  *
 817  * the head node for delayed ref is used to store the sum of all the
 818  * reference count modifications queued up in the rbtree. the head
 819  * node may also store the extent flags to set. This way you can check
 820  * to see what the reference count and extent flags would be if all of
 821  * the delayed refs are not processed.
 822  */
 823 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 824                              struct btrfs_fs_info *fs_info, u64 bytenr,
 825                              u64 offset, int metadata, u64 *refs, u64 *flags)
 826 {
 827         struct btrfs_delayed_ref_head *head;
 828         struct btrfs_delayed_ref_root *delayed_refs;
 829         struct btrfs_path *path;
 830         struct btrfs_extent_item *ei;
 831         struct extent_buffer *leaf;
 832         struct btrfs_key key;
 833         u32 item_size;
 834         u64 num_refs;
 835         u64 extent_flags;
 836         int ret;
 837
 838         /*
 839          * If we don't have skinny metadata, don't bother doing anything
 840          * different
 841          */
 842         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 843                 offset = fs_info->nodesize;
 844                 metadata = 0;
 845         }
 846
 847         path = btrfs_alloc_path();
 848         if (!path)
 849                 return -ENOMEM;
 850
 851         if (!trans) {
 852                 path->skip_locking = 1;
 853                 path->search_commit_root = 1;
 854         }
 855
 856 search_again:
 857         key.objectid = bytenr;
 858         key.offset = offset;
 859         if (metadata)
 860                 key.type = BTRFS_METADATA_ITEM_KEY;
 861         else
 862                 key.type = BTRFS_EXTENT_ITEM_KEY;
 863
 864         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 865         if (ret < 0)
 866                 goto out_free;
 867
 868         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 869                 if (path->slots[0]) {
 870                         path->slots[0]--;
 871                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 872                                               path->slots[0]);
 873                         if (key.objectid == bytenr &&
 874                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 875                             key.offset == fs_info->nodesize)
 876                                 ret = 0;
 877                 }
 878         }
 879
 880         if (ret == 0) {
 881                 leaf = path->nodes[0];
 882                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 883                 if (item_size >= sizeof(*ei)) {
 884                         ei = btrfs_item_ptr(leaf, path->slots[0],
 885                                             struct btrfs_extent_item);
 886                         num_refs = btrfs_extent_refs(leaf, ei);
 887                         extent_flags = btrfs_extent_flags(leaf, ei);
 888                 } else {
 889                         ret = -EINVAL;
 890                         btrfs_print_v0_err(fs_info);
 891                         if (trans)
 892                                 btrfs_abort_transaction(trans, ret);
 893                         else
 894                                 btrfs_handle_fs_error(fs_info, ret, NULL);
 895
 896                         goto out_free;
 897                 }
 898
 899                 BUG_ON(num_refs == 0);
 900         } else {
 901                 num_refs = 0;
 902                 extent_flags = 0;
 903                 ret = 0;
 904         }
 905
 906         if (!trans)
 907                 goto out;
 908
 909         delayed_refs = &trans->transaction->delayed_refs;
 910         spin_lock(&delayed_refs->lock);
 911         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 912         if (head) {
 913                 if (!mutex_trylock(&head->mutex)) {
 914                         refcount_inc(&head->refs);
 915                         spin_unlock(&delayed_refs->lock);
 916
 917                         btrfs_release_path(path);
 918
 919                         /*
 920                          * Mutex was contended, block until it's released and try
 921                          * again
 922                          */
 923                         mutex_lock(&head->mutex);
 924                         mutex_unlock(&head->mutex);
 925                         btrfs_put_delayed_ref_head(head);
 926                         goto search_again;
 927                 }
 928                 spin_lock(&head->lock);
 929                 if (head->extent_op && head->extent_op->update_flags)
 930                         extent_flags |= head->extent_op->flags_to_set;
 931                 else
 932                         BUG_ON(num_refs == 0);
 933
 934                 num_refs += head->ref_mod;
 935                 spin_unlock(&head->lock);
 936                 mutex_unlock(&head->mutex);
 937         }
 938         spin_unlock(&delayed_refs->lock);
 939 out:
 940         WARN_ON(num_refs == 0);
 941         if (refs)
 942                 *refs = num_refs;
 943         if (flags)
 944                 *flags = extent_flags;
 945 out_free:
 946         btrfs_free_path(path);
 947         return ret;
 948 }
 949
 950 /*
 951  * Back reference rules.  Back refs have three main goals:
 952  *
 953  * 1) differentiate between all holders of references to an extent so that
 954  *    when a reference is dropped we can make sure it was a valid reference
 955  *    before freeing the extent.
 956  *
 957  * 2) Provide enough information to quickly find the holders of an extent
 958  *    if we notice a given block is corrupted or bad.
 959  *
 960  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 961  *    maintenance.  This is actually the same as #2, but with a slightly
 962  *    different use case.
 963  *
 964  * There are two kinds of back refs. The implicit back refs is optimized
 965  * for pointers in non-shared tree blocks. For a given pointer in a block,
 966  * back refs of this kind provide information about the block's owner tree
 967  * and the pointer's key. These information allow us to find the block by
 968  * b-tree searching. The full back refs is for pointers in tree blocks not
 969  * referenced by their owner trees. The location of tree block is recorded
 970  * in the back refs. Actually the full back refs is generic, and can be
 971  * used in all cases the implicit back refs is used. The major shortcoming
 972  * of the full back refs is its overhead. Every time a tree block gets
 973  * COWed, we have to update back refs entry for all pointers in it.
 974  *
 975  * For a newly allocated tree block, we use implicit back refs for
 976  * pointers in it. This means most tree related operations only involve
 977  * implicit back refs. For a tree block created in old transaction, the
 978  * only way to drop a reference to it is COW it. So we can detect the
 979  * event that tree block loses its owner tree's reference and do the
 980  * back refs conversion.
 981  *
 982  * When a tree block is COWed through a tree, there are four cases:
 983  *
 984  * The reference count of the block is one and the tree is the block's
 985  * owner tree. Nothing to do in this case.
 986  *
 987  * The reference count of the block is one and the tree is not the
 988  * block's owner tree. In this case, full back refs is used for pointers
 989  * in the block. Remove these full back refs, add implicit back refs for
 990  * every pointers in the new block.
 991  *
 992  * The reference count of the block is greater than one and the tree is
 993  * the block's owner tree. In this case, implicit back refs is used for
 994  * pointers in the block. Add full back refs for every pointers in the
 995  * block, increase lower level extents' reference counts. The original
 996  * implicit back refs are entailed to the new block.
 997  *
 998  * The reference count of the block is greater than one and the tree is
 999  * not the block's owner tree. Add implicit back refs for every pointer in
1000  * the new block, increase lower level extents' reference count.
1001  *
1002  * Back Reference Key composing:
1003  *
1004  * The key objectid corresponds to the first byte in the extent,
1005  * The key type is used to differentiate between types of back refs.
1006  * There are different meanings of the key offset for different types
1007  * of back refs.
1008  *
1009  * File extents can be referenced by:
1010  *
1011  * - multiple snapshots, subvolumes, or different generations in one subvol
1012  * - different files inside a single subvolume
1013  * - different offsets inside a file (bookend extents in file.c)
1014  *
1015  * The extent ref structure for the implicit back refs has fields for:
1016  *
1017  * - Objectid of the subvolume root
1018  * - objectid of the file holding the reference
1019  * - original offset in the file
1020  * - how many bookend extents
1021  *
1022  * The key offset for the implicit back refs is hash of the first
1023  * three fields.
1024  *
1025  * The extent ref structure for the full back refs has field for:
1026  *
1027  * - number of pointers in the tree leaf
1028  *
1029  * The key offset for the implicit back refs is the first byte of
1030  * the tree leaf
1031  *
1032  * When a file extent is allocated, The implicit back refs is used.
1033  * the fields are filled in:
1034  *
1035  *     (root_key.objectid, inode objectid, offset in file, 1)
1036  *
1037  * When a file extent is removed file truncation, we find the
1038  * corresponding implicit back refs and check the following fields:
1039  *
1040  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1041  *
1042  * Btree extents can be referenced by:
1043  *
1044  * - Different subvolumes
1045  *
1046  * Both the implicit back refs and the full back refs for tree blocks
1047  * only consist of key. The key offset for the implicit back refs is
1048  * objectid of block's owner tree. The key offset for the full back refs
1049  * is the first byte of parent block.
1050  *
1051  * When implicit back refs is used, information about the lowest key and
1052  * level of the tree block are required. These information are stored in
1053  * tree block info structure.
1054  */
1055
1056 /*
1057  * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
1058  * is_data == BTRFS_REF_TYPE_DATA, data type is requried,
1059  * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
1060  */
1061 int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
1062                                      struct btrfs_extent_inline_ref *iref,
1063                                      enum btrfs_inline_ref_type is_data)
1064 {
1065         int type = btrfs_extent_inline_ref_type(eb, iref);
1066         u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
1067
1068         if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1069             type == BTRFS_SHARED_BLOCK_REF_KEY ||
1070             type == BTRFS_SHARED_DATA_REF_KEY ||
1071             type == BTRFS_EXTENT_DATA_REF_KEY) {
1072                 if (is_data == BTRFS_REF_TYPE_BLOCK) {
1073                         if (type == BTRFS_TREE_BLOCK_REF_KEY)
1074                                 return type;
1075                         if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1076                                 ASSERT(eb->fs_info);
1077                                 /*
1078                                  * Every shared one has parent tree
1079                                  * block, which must be aligned to
1080                                  * nodesize.
1081                                  */
1082                                 if (offset &&
1083                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1084                                         return type;
1085                         }
1086                 } else if (is_data == BTRFS_REF_TYPE_DATA) {
1087                         if (type == BTRFS_EXTENT_DATA_REF_KEY)
1088                                 return type;
1089                         if (type == BTRFS_SHARED_DATA_REF_KEY) {
1090                                 ASSERT(eb->fs_info);
1091                                 /*
1092                                  * Every shared one has parent tree
1093                                  * block, which must be aligned to
1094                                  * nodesize.
1095                                  */
1096                                 if (offset &&
1097                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1098                                         return type;
1099                         }
1100                 } else {
1101                         ASSERT(is_data == BTRFS_REF_TYPE_ANY);
1102                         return type;
1103                 }
1104         }
1105
1106         btrfs_print_leaf((struct extent_buffer *)eb);
1107         btrfs_err(eb->fs_info, "eb %llu invalid extent inline ref type %d",
1108                   eb->start, type);
1109         WARN_ON(1);
1110
1111         return BTRFS_REF_TYPE_INVALID;
1112 }
1113
1114 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1115 {
1116         u32 high_crc = ~(u32)0;
1117         u32 low_crc = ~(u32)0;
1118         __le64 lenum;
1119
1120         lenum = cpu_to_le64(root_objectid);
1121         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1122         lenum = cpu_to_le64(owner);
1123         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1124         lenum = cpu_to_le64(offset);
1125         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1126
1127         return ((u64)high_crc << 31) ^ (u64)low_crc;
1128 }
1129
1130 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1131                                      struct btrfs_extent_data_ref *ref)
1132 {
1133         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1134                                     btrfs_extent_data_ref_objectid(leaf, ref),
1135                                     btrfs_extent_data_ref_offset(leaf, ref));
1136 }
1137
1138 static int match_extent_data_ref(struct extent_buffer *leaf,
1139                                  struct btrfs_extent_data_ref *ref,
1140                                  u64 root_objectid, u64 owner, u64 offset)
1141 {
1142         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1143             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1144             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1145                 return 0;
1146         return 1;
1147 }
1148
1149 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1150                                            struct btrfs_path *path,
1151                                            u64 bytenr, u64 parent,
1152                                            u64 root_objectid,
1153                                            u64 owner, u64 offset)
1154 {
1155         struct btrfs_root *root = trans->fs_info->extent_root;
1156         struct btrfs_key key;
1157         struct btrfs_extent_data_ref *ref;
1158         struct extent_buffer *leaf;
1159         u32 nritems;
1160         int ret;
1161         int recow;
1162         int err = -ENOENT;
1163
1164         key.objectid = bytenr;
1165         if (parent) {
1166                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1167                 key.offset = parent;
1168         } else {
1169                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1170                 key.offset = hash_extent_data_ref(root_objectid,
1171                                                   owner, offset);
1172         }
1173 again:
1174         recow = 0;
1175         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1176         if (ret < 0) {
1177                 err = ret;
1178                 goto fail;
1179         }
1180
1181         if (parent) {
1182                 if (!ret)
1183                         return 0;
1184                 goto fail;
1185         }
1186
1187         leaf = path->nodes[0];
1188         nritems = btrfs_header_nritems(leaf);
1189         while (1) {
1190                 if (path->slots[0] >= nritems) {
1191                         ret = btrfs_next_leaf(root, path);
1192                         if (ret < 0)
1193                                 err = ret;
1194                         if (ret)
1195                                 goto fail;
1196
1197                         leaf = path->nodes[0];
1198                         nritems = btrfs_header_nritems(leaf);
1199                         recow = 1;
1200                 }
1201
1202                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1203                 if (key.objectid != bytenr ||
1204                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1205                         goto fail;
1206
1207                 ref = btrfs_item_ptr(leaf, path->slots[0],
1208                                      struct btrfs_extent_data_ref);
1209
1210                 if (match_extent_data_ref(leaf, ref, root_objectid,
1211                                           owner, offset)) {
1212                         if (recow) {
1213                                 btrfs_release_path(path);
1214                                 goto again;
1215                         }
1216                         err = 0;
1217                         break;
1218                 }
1219                 path->slots[0]++;
1220         }
1221 fail:
1222         return err;
1223 }
1224
1225 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1226                                            struct btrfs_path *path,
1227                                            u64 bytenr, u64 parent,
1228                                            u64 root_objectid, u64 owner,
1229                                            u64 offset, int refs_to_add)
1230 {
1231         struct btrfs_root *root = trans->fs_info->extent_root;
1232         struct btrfs_key key;
1233         struct extent_buffer *leaf;
1234         u32 size;
1235         u32 num_refs;
1236         int ret;
1237
1238         key.objectid = bytenr;
1239         if (parent) {
1240                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1241                 key.offset = parent;
1242                 size = sizeof(struct btrfs_shared_data_ref);
1243         } else {
1244                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1245                 key.offset = hash_extent_data_ref(root_objectid,
1246                                                   owner, offset);
1247                 size = sizeof(struct btrfs_extent_data_ref);
1248         }
1249
1250         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1251         if (ret && ret != -EEXIST)
1252                 goto fail;
1253
1254         leaf = path->nodes[0];
1255         if (parent) {
1256                 struct btrfs_shared_data_ref *ref;
1257                 ref = btrfs_item_ptr(leaf, path->slots[0],
1258                                      struct btrfs_shared_data_ref);
1259                 if (ret == 0) {
1260                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1261                 } else {
1262                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1263                         num_refs += refs_to_add;
1264                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1265                 }
1266         } else {
1267                 struct btrfs_extent_data_ref *ref;
1268                 while (ret == -EEXIST) {
1269                         ref = btrfs_item_ptr(leaf, path->slots[0],
1270                                              struct btrfs_extent_data_ref);
1271                         if (match_extent_data_ref(leaf, ref, root_objectid,
1272                                                   owner, offset))
1273                                 break;
1274                         btrfs_release_path(path);
1275                         key.offset++;
1276                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1277                                                       size);
1278                         if (ret && ret != -EEXIST)
1279                                 goto fail;
1280
1281                         leaf = path->nodes[0];
1282                 }
1283                 ref = btrfs_item_ptr(leaf, path->slots[0],
1284                                      struct btrfs_extent_data_ref);
1285                 if (ret == 0) {
1286                         btrfs_set_extent_data_ref_root(leaf, ref,
1287                                                        root_objectid);
1288                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1289                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1290                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1291                 } else {
1292                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1293                         num_refs += refs_to_add;
1294                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1295                 }
1296         }
1297         btrfs_mark_buffer_dirty(leaf);
1298         ret = 0;
1299 fail:
1300         btrfs_release_path(path);
1301         return ret;
1302 }
1303
1304 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1305                                            struct btrfs_path *path,
1306                                            int refs_to_drop, int *last_ref)
1307 {
1308         struct btrfs_key key;
1309         struct btrfs_extent_data_ref *ref1 = NULL;
1310         struct btrfs_shared_data_ref *ref2 = NULL;
1311         struct extent_buffer *leaf;
1312         u32 num_refs = 0;
1313         int ret = 0;
1314
1315         leaf = path->nodes[0];
1316         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1317
1318         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1319                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1320                                       struct btrfs_extent_data_ref);
1321                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1322         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1323                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1324                                       struct btrfs_shared_data_ref);
1325                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1326         } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
1327                 btrfs_print_v0_err(trans->fs_info);
1328                 btrfs_abort_transaction(trans, -EINVAL);
1329                 return -EINVAL;
1330         } else {
1331                 BUG();
1332         }
1333
1334         BUG_ON(num_refs < refs_to_drop);
1335         num_refs -= refs_to_drop;
1336
1337         if (num_refs == 0) {
1338                 ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
1339                 *last_ref = 1;
1340         } else {
1341                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1342                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1343                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1344                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1345                 btrfs_mark_buffer_dirty(leaf);
1346         }
1347         return ret;
1348 }
1349
1350 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1351                                           struct btrfs_extent_inline_ref *iref)
1352 {
1353         struct btrfs_key key;
1354         struct extent_buffer *leaf;
1355         struct btrfs_extent_data_ref *ref1;
1356         struct btrfs_shared_data_ref *ref2;
1357         u32 num_refs = 0;
1358         int type;
1359
1360         leaf = path->nodes[0];
1361         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1362
1363         BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
1364         if (iref) {
1365                 /*
1366                  * If type is invalid, we should have bailed out earlier than
1367                  * this call.
1368                  */
1369                 type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
1370                 ASSERT(type != BTRFS_REF_TYPE_INVALID);
1371                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1372                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1373                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1374                 } else {
1375                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1376                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1377                 }
1378         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1379                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1380                                       struct btrfs_extent_data_ref);
1381                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1382         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1383                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1384                                       struct btrfs_shared_data_ref);
1385                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1386         } else {
1387                 WARN_ON(1);
1388         }
1389         return num_refs;
1390 }
1391
1392 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1393                                           struct btrfs_path *path,
1394                                           u64 bytenr, u64 parent,
1395                                           u64 root_objectid)
1396 {
1397         struct btrfs_root *root = trans->fs_info->extent_root;
1398         struct btrfs_key key;
1399         int ret;
1400
1401         key.objectid = bytenr;
1402         if (parent) {
1403                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1404                 key.offset = parent;
1405         } else {
1406                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1407                 key.offset = root_objectid;
1408         }
1409
1410         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1411         if (ret > 0)
1412                 ret = -ENOENT;
1413         return ret;
1414 }
1415
1416 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1417                                           struct btrfs_path *path,
1418                                           u64 bytenr, u64 parent,
1419                                           u64 root_objectid)
1420 {
1421         struct btrfs_key key;
1422         int ret;
1423
1424         key.objectid = bytenr;
1425         if (parent) {
1426                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1427                 key.offset = parent;
1428         } else {
1429                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1430                 key.offset = root_objectid;
1431         }
1432
1433         ret = btrfs_insert_empty_item(trans, trans->fs_info->extent_root,
1434                                       path, &key, 0);
1435         btrfs_release_path(path);
1436         return ret;
1437 }
1438
1439 static inline int extent_ref_type(u64 parent, u64 owner)
1440 {
1441         int type;
1442         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1443                 if (parent > 0)
1444                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1445                 else
1446                         type = BTRFS_TREE_BLOCK_REF_KEY;
1447         } else {
1448                 if (parent > 0)
1449                         type = BTRFS_SHARED_DATA_REF_KEY;
1450                 else
1451                         type = BTRFS_EXTENT_DATA_REF_KEY;
1452         }
1453         return type;
1454 }
1455
1456 static int find_next_key(struct btrfs_path *path, int level,
1457                          struct btrfs_key *key)
1458
1459 {
1460         for (; level < BTRFS_MAX_LEVEL; level++) {
1461                 if (!path->nodes[level])
1462                         break;
1463                 if (path->slots[level] + 1 >=
1464                     btrfs_header_nritems(path->nodes[level]))
1465                         continue;
1466                 if (level == 0)
1467                         btrfs_item_key_to_cpu(path->nodes[level], key,
1468                                               path->slots[level] + 1);
1469                 else
1470                         btrfs_node_key_to_cpu(path->nodes[level], key,
1471                                               path->slots[level] + 1);
1472                 return 0;
1473         }
1474         return 1;
1475 }
1476
1477 /*
1478  * look for inline back ref. if back ref is found, *ref_ret is set
1479  * to the address of inline back ref, and 0 is returned.
1480  *
1481  * if back ref isn't found, *ref_ret is set to the address where it
1482  * should be inserted, and -ENOENT is returned.
1483  *
1484  * if insert is true and there are too many inline back refs, the path
1485  * points to the extent item, and -EAGAIN is returned.
1486  *
1487  * NOTE: inline back refs are ordered in the same way that back ref
1488  *       items in the tree are ordered.
1489  */
1490 static noinline_for_stack
1491 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1492                                  struct btrfs_path *path,
1493                                  struct btrfs_extent_inline_ref **ref_ret,
1494                                  u64 bytenr, u64 num_bytes,
1495                                  u64 parent, u64 root_objectid,
1496                                  u64 owner, u64 offset, int insert)
1497 {
1498         struct btrfs_fs_info *fs_info = trans->fs_info;
1499         struct btrfs_root *root = fs_info->extent_root;
1500         struct btrfs_key key;
1501         struct extent_buffer *leaf;
1502         struct btrfs_extent_item *ei;
1503         struct btrfs_extent_inline_ref *iref;
1504         u64 flags;
1505         u64 item_size;
1506         unsigned long ptr;
1507         unsigned long end;
1508         int extra_size;
1509         int type;
1510         int want;
1511         int ret;
1512         int err = 0;
1513         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
1514         int needed;
1515
1516         key.objectid = bytenr;
1517         key.type = BTRFS_EXTENT_ITEM_KEY;
1518         key.offset = num_bytes;
1519
1520         want = extent_ref_type(parent, owner);
1521         if (insert) {
1522                 extra_size = btrfs_extent_inline_ref_size(want);
1523                 path->keep_locks = 1;
1524         } else
1525                 extra_size = -1;
1526
1527         /*
1528          * Owner is our level, so we can just add one to get the level for the
1529          * block we are interested in.
1530          */
1531         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1532                 key.type = BTRFS_METADATA_ITEM_KEY;
1533                 key.offset = owner;
1534         }
1535
1536 again:
1537         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1538         if (ret < 0) {
1539                 err = ret;
1540                 goto out;
1541         }
1542
1543         /*
1544          * We may be a newly converted file system which still has the old fat
1545          * extent entries for metadata, so try and see if we have one of those.
1546          */
1547         if (ret > 0 && skinny_metadata) {
1548                 skinny_metadata = false;
1549                 if (path->slots[0]) {
1550                         path->slots[0]--;
1551                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1552                                               path->slots[0]);
1553                         if (key.objectid == bytenr &&
1554                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1555                             key.offset == num_bytes)
1556                                 ret = 0;
1557                 }
1558                 if (ret) {
1559                         key.objectid = bytenr;
1560                         key.type = BTRFS_EXTENT_ITEM_KEY;
1561                         key.offset = num_bytes;
1562                         btrfs_release_path(path);
1563                         goto again;
1564                 }
1565         }
1566
1567         if (ret && !insert) {
1568                 err = -ENOENT;
1569                 goto out;
1570         } else if (WARN_ON(ret)) {
1571                 err = -EIO;
1572                 goto out;
1573         }
1574
1575         leaf = path->nodes[0];
1576         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1577         if (unlikely(item_size < sizeof(*ei))) {
1578                 err = -EINVAL;
1579                 btrfs_print_v0_err(fs_info);
1580                 btrfs_abort_transaction(trans, err);
1581                 goto out;
1582         }
1583
1584         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1585         flags = btrfs_extent_flags(leaf, ei);
1586
1587         ptr = (unsigned long)(ei + 1);
1588         end = (unsigned long)ei + item_size;
1589
1590         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1591                 ptr += sizeof(struct btrfs_tree_block_info);
1592                 BUG_ON(ptr > end);
1593         }
1594
1595         if (owner >= BTRFS_FIRST_FREE_OBJECTID)
1596                 needed = BTRFS_REF_TYPE_DATA;
1597         else
1598                 needed = BTRFS_REF_TYPE_BLOCK;
1599
1600         err = -ENOENT;
1601         while (1) {
1602                 if (ptr >= end) {
1603                         WARN_ON(ptr > end);
1604                         break;
1605                 }
1606                 iref = (struct btrfs_extent_inline_ref *)ptr;
1607                 type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
1608                 if (type == BTRFS_REF_TYPE_INVALID) {
1609                         err = -EUCLEAN;
1610                         goto out;
1611                 }
1612
1613                 if (want < type)
1614                         break;
1615                 if (want > type) {
1616                         ptr += btrfs_extent_inline_ref_size(type);
1617                         continue;
1618                 }
1619
1620                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1621                         struct btrfs_extent_data_ref *dref;
1622                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1623                         if (match_extent_data_ref(leaf, dref, root_objectid,
1624                                                   owner, offset)) {
1625                                 err = 0;
1626                                 break;
1627                         }
1628                         if (hash_extent_data_ref_item(leaf, dref) <
1629                             hash_extent_data_ref(root_objectid, owner, offset))
1630                                 break;
1631                 } else {
1632                         u64 ref_offset;
1633                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1634                         if (parent > 0) {
1635                                 if (parent == ref_offset) {
1636                                         err = 0;
1637                                         break;
1638                                 }
1639                                 if (ref_offset < parent)
1640                                         break;
1641                         } else {
1642                                 if (root_objectid == ref_offset) {
1643                                         err = 0;
1644                                         break;
1645                                 }
1646                                 if (ref_offset < root_objectid)
1647                                         break;
1648                         }
1649                 }
1650                 ptr += btrfs_extent_inline_ref_size(type);
1651         }
1652         if (err == -ENOENT && insert) {
1653                 if (item_size + extra_size >=
1654                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1655                         err = -EAGAIN;
1656                         goto out;
1657                 }
1658                 /*
1659                  * To add new inline back ref, we have to make sure
1660                  * there is no corresponding back ref item.
1661                  * For simplicity, we just do not add new inline back
1662                  * ref if there is any kind of item for this block
1663                  */
1664                 if (find_next_key(path, 0, &key) == 0 &&
1665                     key.objectid == bytenr &&
1666                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1667                         err = -EAGAIN;
1668                         goto out;
1669                 }
1670         }
1671         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1672 out:
1673         if (insert) {
1674                 path->keep_locks = 0;
1675                 btrfs_unlock_up_safe(path, 1);
1676         }
1677         return err;
1678 }
1679
1680 /*
1681  * helper to add new inline back ref
1682  */
1683 static noinline_for_stack
1684 void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
1685                                  struct btrfs_path *path,
1686                                  struct btrfs_extent_inline_ref *iref,
1687                                  u64 parent, u64 root_objectid,
1688                                  u64 owner, u64 offset, int refs_to_add,
1689                                  struct btrfs_delayed_extent_op *extent_op)
1690 {
1691         struct extent_buffer *leaf;
1692         struct btrfs_extent_item *ei;
1693         unsigned long ptr;
1694         unsigned long end;
1695         unsigned long item_offset;
1696         u64 refs;
1697         int size;
1698         int type;
1699
1700         leaf = path->nodes[0];
1701         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1702         item_offset = (unsigned long)iref - (unsigned long)ei;
1703
1704         type = extent_ref_type(parent, owner);
1705         size = btrfs_extent_inline_ref_size(type);
1706
1707         btrfs_extend_item(fs_info, path, size);
1708
1709         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1710         refs = btrfs_extent_refs(leaf, ei);
1711         refs += refs_to_add;
1712         btrfs_set_extent_refs(leaf, ei, refs);
1713         if (extent_op)
1714                 __run_delayed_extent_op(extent_op, leaf, ei);
1715
1716         ptr = (unsigned long)ei + item_offset;
1717         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1718         if (ptr < end - size)
1719                 memmove_extent_buffer(leaf, ptr + size, ptr,
1720                                       end - size - ptr);
1721
1722         iref = (struct btrfs_extent_inline_ref *)ptr;
1723         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1724         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1725                 struct btrfs_extent_data_ref *dref;
1726                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1727                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1728                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1729                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1730                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1731         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1732                 struct btrfs_shared_data_ref *sref;
1733                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1734                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1735                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1736         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1737                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1738         } else {
1739                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1740         }
1741         btrfs_mark_buffer_dirty(leaf);
1742 }
1743
1744 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1745                                  struct btrfs_path *path,
1746                                  struct btrfs_extent_inline_ref **ref_ret,
1747                                  u64 bytenr, u64 num_bytes, u64 parent,
1748                                  u64 root_objectid, u64 owner, u64 offset)
1749 {
1750         int ret;
1751
1752         ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
1753                                            num_bytes, parent, root_objectid,
1754                                            owner, offset, 0);
1755         if (ret != -ENOENT)
1756                 return ret;
1757
1758         btrfs_release_path(path);
1759         *ref_ret = NULL;
1760
1761         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1762                 ret = lookup_tree_block_ref(trans, path, bytenr, parent,
1763                                             root_objectid);
1764         } else {
1765                 ret = lookup_extent_data_ref(trans, path, bytenr, parent,
1766                                              root_objectid, owner, offset);
1767         }
1768         return ret;
1769 }
1770
1771 /*
1772  * helper to update/remove inline back ref
1773  */
1774 static noinline_for_stack
1775 void update_inline_extent_backref(struct btrfs_path *path,
1776                                   struct btrfs_extent_inline_ref *iref,
1777                                   int refs_to_mod,
1778                                   struct btrfs_delayed_extent_op *extent_op,
1779                                   int *last_ref)
1780 {
1781         struct extent_buffer *leaf = path->nodes[0];
1782         struct btrfs_fs_info *fs_info = leaf->fs_info;
1783         struct btrfs_extent_item *ei;
1784         struct btrfs_extent_data_ref *dref = NULL;
1785         struct btrfs_shared_data_ref *sref = NULL;
1786         unsigned long ptr;
1787         unsigned long end;
1788         u32 item_size;
1789         int size;
1790         int type;
1791         u64 refs;
1792
1793         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1794         refs = btrfs_extent_refs(leaf, ei);
1795         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1796         refs += refs_to_mod;
1797         btrfs_set_extent_refs(leaf, ei, refs);
1798         if (extent_op)
1799                 __run_delayed_extent_op(extent_op, leaf, ei);
1800
1801         /*
1802          * If type is invalid, we should have bailed out after
1803          * lookup_inline_extent_backref().
1804          */
1805         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1806         ASSERT(type != BTRFS_REF_TYPE_INVALID);
1807
1808         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1809                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1810                 refs = btrfs_extent_data_ref_count(leaf, dref);
1811         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1812                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1813                 refs = btrfs_shared_data_ref_count(leaf, sref);
1814         } else {
1815                 refs = 1;
1816                 BUG_ON(refs_to_mod != -1);
1817         }
1818
1819         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1820         refs += refs_to_mod;
1821
1822         if (refs > 0) {
1823                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1824                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1825                 else
1826                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1827         } else {
1828                 *last_ref = 1;
1829                 size =  btrfs_extent_inline_ref_size(type);
1830                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1831                 ptr = (unsigned long)iref;
1832                 end = (unsigned long)ei + item_size;
1833                 if (ptr + size < end)
1834                         memmove_extent_buffer(leaf, ptr, ptr + size,
1835                                               end - ptr - size);
1836                 item_size -= size;
1837                 btrfs_truncate_item(fs_info, path, item_size, 1);
1838         }
1839         btrfs_mark_buffer_dirty(leaf);
1840 }
1841
1842 static noinline_for_stack
1843 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1844                                  struct btrfs_path *path,
1845                                  u64 bytenr, u64 num_bytes, u64 parent,
1846                                  u64 root_objectid, u64 owner,
1847                                  u64 offset, int refs_to_add,
1848                                  struct btrfs_delayed_extent_op *extent_op)
1849 {
1850         struct btrfs_extent_inline_ref *iref;
1851         int ret;
1852
1853         ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
1854                                            num_bytes, parent, root_objectid,
1855                                            owner, offset, 1);
1856         if (ret == 0) {
1857                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1858                 update_inline_extent_backref(path, iref, refs_to_add,
1859                                              extent_op, NULL);
1860         } else if (ret == -ENOENT) {
1861                 setup_inline_extent_backref(trans->fs_info, path, iref, parent,
1862                                             root_objectid, owner, offset,
1863                                             refs_to_add, extent_op);
1864                 ret = 0;
1865         }
1866         return ret;
1867 }
1868
1869 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1870                                  struct btrfs_path *path,
1871                                  u64 bytenr, u64 parent, u64 root_objectid,
1872                                  u64 owner, u64 offset, int refs_to_add)
1873 {
1874         int ret;
1875         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1876                 BUG_ON(refs_to_add != 1);
1877                 ret = insert_tree_block_ref(trans, path, bytenr, parent,
1878                                             root_objectid);
1879         } else {
1880                 ret = insert_extent_data_ref(trans, path, bytenr, parent,
1881                                              root_objectid, owner, offset,
1882                                              refs_to_add);
1883         }
1884         return ret;
1885 }
1886
1887 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1888                                  struct btrfs_path *path,
1889                                  struct btrfs_extent_inline_ref *iref,
1890                                  int refs_to_drop, int is_data, int *last_ref)
1891 {
1892         int ret = 0;
1893
1894         BUG_ON(!is_data && refs_to_drop != 1);
1895         if (iref) {
1896                 update_inline_extent_backref(path, iref, -refs_to_drop, NULL,
1897                                              last_ref);
1898         } else if (is_data) {
1899                 ret = remove_extent_data_ref(trans, path, refs_to_drop,
1900                                              last_ref);
1901         } else {
1902                 *last_ref = 1;
1903                 ret = btrfs_del_item(trans, trans->fs_info->extent_root, path);
1904         }
1905         return ret;
1906 }
1907
1908 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
1909 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1910                                u64 *discarded_bytes)
1911 {
1912         int j, ret = 0;
1913         u64 bytes_left, end;
1914         u64 aligned_start = ALIGN(start, 1 << 9);
1915
1916         if (WARN_ON(start != aligned_start)) {
1917                 len -= aligned_start - start;
1918                 len = round_down(len, 1 << 9);
1919                 start = aligned_start;
1920         }
1921
1922         *discarded_bytes = 0;
1923
1924         if (!len)
1925                 return 0;
1926
1927         end = start + len;
1928         bytes_left = len;
1929
1930         /* Skip any superblocks on this device. */
1931         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1932                 u64 sb_start = btrfs_sb_offset(j);
1933                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1934                 u64 size = sb_start - start;
1935
1936                 if (!in_range(sb_start, start, bytes_left) &&
1937                     !in_range(sb_end, start, bytes_left) &&
1938                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1939                         continue;
1940
1941                 /*
1942                  * Superblock spans beginning of range.  Adjust start and
1943                  * try again.
1944                  */
1945                 if (sb_start <= start) {
1946                         start += sb_end - start;
1947                         if (start > end) {
1948                                 bytes_left = 0;
1949                                 break;
1950                         }
1951                         bytes_left = end - start;
1952                         continue;
1953                 }
1954
1955                 if (size) {
1956                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
1957                                                    GFP_NOFS, 0);
1958                         if (!ret)
1959                                 *discarded_bytes += size;
1960                         else if (ret != -EOPNOTSUPP)
1961                                 return ret;
1962                 }
1963
1964                 start = sb_end;
1965                 if (start > end) {
1966                         bytes_left = 0;
1967                         break;
1968                 }
1969                 bytes_left = end - start;
1970         }
1971
1972         if (bytes_left) {
1973                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
1974                                            GFP_NOFS, 0);
1975                 if (!ret)
1976                         *discarded_bytes += bytes_left;
1977         }
1978         return ret;
1979 }
1980
1981 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
1982                          u64 num_bytes, u64 *actual_bytes)
1983 {
1984         int ret;
1985         u64 discarded_bytes = 0;
1986         struct btrfs_bio *bbio = NULL;
1987
1988
1989         /*
1990          * Avoid races with device replace and make sure our bbio has devices
1991          * associated to its stripes that don't go away while we are discarding.
1992          */
1993         btrfs_bio_counter_inc_blocked(fs_info);
1994         /* Tell the block device(s) that the sectors can be discarded */
1995         ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
1996                               &bbio, 0);
1997         /* Error condition is -ENOMEM */
1998         if (!ret) {
1999                 struct btrfs_bio_stripe *stripe = bbio->stripes;
2000                 int i;
2001
2002
2003                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2004                         u64 bytes;
2005                         struct request_queue *req_q;
2006
2007                         if (!stripe->dev->bdev) {
2008                                 ASSERT(btrfs_test_opt(fs_info, DEGRADED));
2009                                 continue;
2010                         }
2011                         req_q = bdev_get_queue(stripe->dev->bdev);
2012                         if (!blk_queue_discard(req_q))
2013                                 continue;
2014
2015                         ret = btrfs_issue_discard(stripe->dev->bdev,
2016                                                   stripe->physical,
2017                                                   stripe->length,
2018                                                   &bytes);
2019                         if (!ret)
2020                                 discarded_bytes += bytes;
2021                         else if (ret != -EOPNOTSUPP)
2022                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2023
2024                         /*
2025                          * Just in case we get back EOPNOTSUPP for some reason,
2026                          * just ignore the return value so we don't screw up
2027                          * people calling discard_extent.
2028                          */
2029                         ret = 0;
2030                 }
2031                 btrfs_put_bbio(bbio);
2032         }
2033         btrfs_bio_counter_dec(fs_info);
2034
2035         if (actual_bytes)
2036                 *actual_bytes = discarded_bytes;
2037
2038
2039         if (ret == -EOPNOTSUPP)
2040                 ret = 0;
2041         return ret;
2042 }
2043
2044 /* Can return -ENOMEM */
2045 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2046                          struct btrfs_root *root,
2047                          u64 bytenr, u64 num_bytes, u64 parent,
2048                          u64 root_objectid, u64 owner, u64 offset)
2049 {
2050         struct btrfs_fs_info *fs_info = root->fs_info;
2051         int old_ref_mod, new_ref_mod;
2052         int ret;
2053
2054         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2055                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2056
2057         btrfs_ref_tree_mod(root, bytenr, num_bytes, parent, root_objectid,
2058                            owner, offset, BTRFS_ADD_DELAYED_REF);
2059
2060         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2061                 ret = btrfs_add_delayed_tree_ref(trans, bytenr,
2062                                                  num_bytes, parent,
2063                                                  root_objectid, (int)owner,
2064                                                  BTRFS_ADD_DELAYED_REF, NULL,
2065                                                  &old_ref_mod, &new_ref_mod);
2066         } else {
2067                 ret = btrfs_add_delayed_data_ref(trans, bytenr,
2068                                                  num_bytes, parent,
2069                                                  root_objectid, owner, offset,
2070                                                  0, BTRFS_ADD_DELAYED_REF,
2071                                                  &old_ref_mod, &new_ref_mod);
2072         }
2073
2074         if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0) {
2075                 bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
2076
2077                 add_pinned_bytes(fs_info, -num_bytes, metadata, root_objectid);
2078         }
2079
2080         return ret;
2081 }
2082
2083 /*
2084  * __btrfs_inc_extent_ref - insert backreference for a given extent
2085  *
2086  * @trans:          Handle of transaction
2087  *
2088  * @node:           The delayed ref node used to get the bytenr/length for
2089  *                  extent whose references are incremented.
2090  *
2091  * @parent:         If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
2092  *                  BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
2093  *                  bytenr of the parent block. Since new extents are always
2094  *                  created with indirect references, this will only be the case
2095  *                  when relocating a shared extent. In that case, root_objectid
2096  *                  will be BTRFS_TREE_RELOC_OBJECTID. Otheriwse, parent must
2097  *                  be 0
2098  *
2099  * @root_objectid:  The id of the root where this modification has originated,
2100  *                  this can be either one of the well-known metadata trees or
2101  *                  the subvolume id which references this extent.
2102  *
2103  * @owner:          For data extents it is the inode number of the owning file.
2104  *                  For metadata extents this parameter holds the level in the
2105  *                  tree of the extent.
2106  *
2107  * @offset:         For metadata extents the offset is ignored and is currently
2108  *                  always passed as 0. For data extents it is the fileoffset
2109  *                  this extent belongs to.
2110  *
2111  * @refs_to_add     Number of references to add
2112  *
2113  * @extent_op       Pointer to a structure, holding information necessary when
2114  *                  updating a tree block's flags
2115  *
2116  */
2117 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2118                                   struct btrfs_delayed_ref_node *node,
2119                                   u64 parent, u64 root_objectid,
2120                                   u64 owner, u64 offset, int refs_to_add,
2121                                   struct btrfs_delayed_extent_op *extent_op)
2122 {
2123         struct btrfs_path *path;
2124         struct extent_buffer *leaf;
2125         struct btrfs_extent_item *item;
2126         struct btrfs_key key;
2127         u64 bytenr = node->bytenr;
2128         u64 num_bytes = node->num_bytes;
2129         u64 refs;
2130         int ret;
2131
2132         path = btrfs_alloc_path();
2133         if (!path)
2134                 return -ENOMEM;
2135
2136         path->reada = READA_FORWARD;
2137         path->leave_spinning = 1;
2138         /* this will setup the path even if it fails to insert the back ref */
2139         ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
2140                                            parent, root_objectid, owner,
2141                                            offset, refs_to_add, extent_op);
2142         if ((ret < 0 && ret != -EAGAIN) || !ret)
2143                 goto out;
2144
2145         /*
2146          * Ok we had -EAGAIN which means we didn't have space to insert and
2147          * inline extent ref, so just update the reference count and add a
2148          * normal backref.
2149          */
2150         leaf = path->nodes[0];
2151         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2152         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2153         refs = btrfs_extent_refs(leaf, item);
2154         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2155         if (extent_op)
2156                 __run_delayed_extent_op(extent_op, leaf, item);
2157
2158         btrfs_mark_buffer_dirty(leaf);
2159         btrfs_release_path(path);
2160
2161         path->reada = READA_FORWARD;
2162         path->leave_spinning = 1;
2163         /* now insert the actual backref */
2164         ret = insert_extent_backref(trans, path, bytenr, parent, root_objectid,
2165                                     owner, offset, refs_to_add);
2166         if (ret)
2167                 btrfs_abort_transaction(trans, ret);
2168 out:
2169         btrfs_free_path(path);
2170         return ret;
2171 }
2172
2173 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2174                                 struct btrfs_delayed_ref_node *node,
2175                                 struct btrfs_delayed_extent_op *extent_op,
2176                                 int insert_reserved)
2177 {
2178         int ret = 0;
2179         struct btrfs_delayed_data_ref *ref;
2180         struct btrfs_key ins;
2181         u64 parent = 0;
2182         u64 ref_root = 0;
2183         u64 flags = 0;
2184
2185         ins.objectid = node->bytenr;
2186         ins.offset = node->num_bytes;
2187         ins.type = BTRFS_EXTENT_ITEM_KEY;
2188
2189         ref = btrfs_delayed_node_to_data_ref(node);
2190         trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action);
2191
2192         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2193                 parent = ref->parent;
2194         ref_root = ref->root;
2195
2196         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2197                 if (extent_op)
2198                         flags |= extent_op->flags_to_set;
2199                 ret = alloc_reserved_file_extent(trans, parent, ref_root,
2200                                                  flags, ref->objectid,
2201                                                  ref->offset, &ins,
2202                                                  node->ref_mod);
2203         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2204                 ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
2205                                              ref->objectid, ref->offset,
2206                                              node->ref_mod, extent_op);
2207         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2208                 ret = __btrfs_free_extent(trans, node, parent,
2209                                           ref_root, ref->objectid,
2210                                           ref->offset, node->ref_mod,
2211                                           extent_op);
2212         } else {
2213                 BUG();
2214         }
2215         return ret;
2216 }
2217
2218 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2219                                     struct extent_buffer *leaf,
2220                                     struct btrfs_extent_item *ei)
2221 {
2222         u64 flags = btrfs_extent_flags(leaf, ei);
2223         if (extent_op->update_flags) {
2224                 flags |= extent_op->flags_to_set;
2225                 btrfs_set_extent_flags(leaf, ei, flags);
2226         }
2227
2228         if (extent_op->update_key) {
2229                 struct btrfs_tree_block_info *bi;
2230                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2231                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2232                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2233         }
2234 }
2235
2236 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2237                                  struct btrfs_delayed_ref_head *head,
2238                                  struct btrfs_delayed_extent_op *extent_op)
2239 {
2240         struct btrfs_fs_info *fs_info = trans->fs_info;
2241         struct btrfs_key key;
2242         struct btrfs_path *path;
2243         struct btrfs_extent_item *ei;
2244         struct extent_buffer *leaf;
2245         u32 item_size;
2246         int ret;
2247         int err = 0;
2248         int metadata = !extent_op->is_data;
2249
2250         if (trans->aborted)
2251                 return 0;
2252
2253         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2254                 metadata = 0;
2255
2256         path = btrfs_alloc_path();
2257         if (!path)
2258                 return -ENOMEM;
2259
2260         key.objectid = head->bytenr;
2261
2262         if (metadata) {
2263                 key.type = BTRFS_METADATA_ITEM_KEY;
2264                 key.offset = extent_op->level;
2265         } else {
2266                 key.type = BTRFS_EXTENT_ITEM_KEY;
2267                 key.offset = head->num_bytes;
2268         }
2269
2270 again:
2271         path->reada = READA_FORWARD;
2272         path->leave_spinning = 1;
2273         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
2274         if (ret < 0) {
2275                 err = ret;
2276                 goto out;
2277         }
2278         if (ret > 0) {
2279                 if (metadata) {
2280                         if (path->slots[0] > 0) {
2281                                 path->slots[0]--;
2282                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2283                                                       path->slots[0]);
2284                                 if (key.objectid == head->bytenr &&
2285                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2286                                     key.offset == head->num_bytes)
2287                                         ret = 0;
2288                         }
2289                         if (ret > 0) {
2290                                 btrfs_release_path(path);
2291                                 metadata = 0;
2292
2293                                 key.objectid = head->bytenr;
2294                                 key.offset = head->num_bytes;
2295                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2296                                 goto again;
2297                         }
2298                 } else {
2299                         err = -EIO;
2300                         goto out;
2301                 }
2302         }
2303
2304         leaf = path->nodes[0];
2305         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2306
2307         if (unlikely(item_size < sizeof(*ei))) {
2308                 err = -EINVAL;
2309                 btrfs_print_v0_err(fs_info);
2310                 btrfs_abort_transaction(trans, err);
2311                 goto out;
2312         }
2313
2314         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2315         __run_delayed_extent_op(extent_op, leaf, ei);
2316
2317         btrfs_mark_buffer_dirty(leaf);
2318 out:
2319         btrfs_free_path(path);
2320         return err;
2321 }
2322
2323 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2324                                 struct btrfs_delayed_ref_node *node,
2325                                 struct btrfs_delayed_extent_op *extent_op,
2326                                 int insert_reserved)
2327 {
2328         int ret = 0;
2329         struct btrfs_delayed_tree_ref *ref;
2330         u64 parent = 0;
2331         u64 ref_root = 0;
2332
2333         ref = btrfs_delayed_node_to_tree_ref(node);
2334         trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action);
2335
2336         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2337                 parent = ref->parent;
2338         ref_root = ref->root;
2339
2340         if (node->ref_mod != 1) {
2341                 btrfs_err(trans->fs_info,
2342         "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
2343                           node->bytenr, node->ref_mod, node->action, ref_root,
2344                           parent);
2345                 return -EIO;
2346         }
2347         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2348                 BUG_ON(!extent_op || !extent_op->update_flags);
2349                 ret = alloc_reserved_tree_block(trans, node, extent_op);
2350         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2351                 ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
2352                                              ref->level, 0, 1, extent_op);
2353         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2354                 ret = __btrfs_free_extent(trans, node, parent, ref_root,
2355                                           ref->level, 0, 1, extent_op);
2356         } else {
2357                 BUG();
2358         }
2359         return ret;
2360 }
2361
2362 /* helper function to actually process a single delayed ref entry */
2363 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2364                                struct btrfs_delayed_ref_node *node,
2365                                struct btrfs_delayed_extent_op *extent_op,
2366                                int insert_reserved)
2367 {
2368         int ret = 0;
2369
2370         if (trans->aborted) {
2371                 if (insert_reserved)
2372                         btrfs_pin_extent(trans->fs_info, node->bytenr,
2373                                          node->num_bytes, 1);
2374                 return 0;
2375         }
2376
2377         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2378             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2379                 ret = run_delayed_tree_ref(trans, node, extent_op,
2380                                            insert_reserved);
2381         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2382                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2383                 ret = run_delayed_data_ref(trans, node, extent_op,
2384                                            insert_reserved);
2385         else
2386                 BUG();
2387         if (ret && insert_reserved)
2388                 btrfs_pin_extent(trans->fs_info, node->bytenr,
2389                                  node->num_bytes, 1);
2390         return ret;
2391 }
2392
2393 static inline struct btrfs_delayed_ref_node *
2394 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2395 {
2396         struct btrfs_delayed_ref_node *ref;
2397
2398         if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
2399                 return NULL;
2400
2401         /*
2402          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2403          * This is to prevent a ref count from going down to zero, which deletes
2404          * the extent item from the extent tree, when there still are references
2405          * to add, which would fail because they would not find the extent item.
2406          */
2407         if (!list_empty(&head->ref_add_list))
2408                 return list_first_entry(&head->ref_add_list,
2409                                 struct btrfs_delayed_ref_node, add_list);
2410
2411         ref = rb_entry(rb_first_cached(&head->ref_tree),
2412                        struct btrfs_delayed_ref_node, ref_node);
2413         ASSERT(list_empty(&ref->add_list));
2414         return ref;
2415 }
2416
2417 static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
2418                                       struct btrfs_delayed_ref_head *head)
2419 {
2420         spin_lock(&delayed_refs->lock);
2421         head->processing = 0;
2422         delayed_refs->num_heads_ready++;
2423         spin_unlock(&delayed_refs->lock);
2424         btrfs_delayed_ref_unlock(head);
2425 }
2426
2427 static int cleanup_extent_op(struct btrfs_trans_handle *trans,
2428                              struct btrfs_delayed_ref_head *head)
2429 {
2430         struct btrfs_delayed_extent_op *extent_op = head->extent_op;
2431         int ret;
2432
2433         if (!extent_op)
2434                 return 0;
2435         head->extent_op = NULL;
2436         if (head->must_insert_reserved) {
2437                 btrfs_free_delayed_extent_op(extent_op);
2438                 return 0;
2439         }
2440         spin_unlock(&head->lock);
2441         ret = run_delayed_extent_op(trans, head, extent_op);
2442         btrfs_free_delayed_extent_op(extent_op);
2443         return ret ? ret : 1;
2444 }
2445
2446 static int cleanup_ref_head(struct btrfs_trans_handle *trans,
2447                             struct btrfs_delayed_ref_head *head)
2448 {
2449
2450         struct btrfs_fs_info *fs_info = trans->fs_info;
2451         struct btrfs_delayed_ref_root *delayed_refs;
2452         int ret;
2453
2454         delayed_refs = &trans->transaction->delayed_refs;
2455
2456         ret = cleanup_extent_op(trans, head);
2457         if (ret < 0) {
2458                 unselect_delayed_ref_head(delayed_refs, head);
2459                 btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2460                 return ret;
2461         } else if (ret) {
2462                 return ret;
2463         }
2464
2465         /*
2466          * Need to drop our head ref lock and re-acquire the delayed ref lock
2467          * and then re-check to make sure nobody got added.
2468          */
2469         spin_unlock(&head->lock);
2470         spin_lock(&delayed_refs->lock);
2471         spin_lock(&head->lock);
2472         if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
2473                 spin_unlock(&head->lock);
2474                 spin_unlock(&delayed_refs->lock);
2475                 return 1;
2476         }
2477         delayed_refs->num_heads--;
2478         rb_erase_cached(&head->href_node, &delayed_refs->href_root);
2479         RB_CLEAR_NODE(&head->href_node);
2480         spin_unlock(&head->lock);
2481         spin_unlock(&delayed_refs->lock);
2482         atomic_dec(&delayed_refs->num_entries);
2483
2484         trace_run_delayed_ref_head(fs_info, head, 0);
2485
2486         if (head->total_ref_mod < 0) {
2487                 struct btrfs_space_info *space_info;
2488                 u64 flags;
2489
2490                 if (head->is_data)
2491                         flags = BTRFS_BLOCK_GROUP_DATA;
2492                 else if (head->is_system)
2493                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
2494                 else
2495                         flags = BTRFS_BLOCK_GROUP_METADATA;
2496                 space_info = __find_space_info(fs_info, flags);
2497                 ASSERT(space_info);
2498                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
2499                                    -head->num_bytes,
2500                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
2501
2502                 if (head->is_data) {
2503                         spin_lock(&delayed_refs->lock);
2504                         delayed_refs->pending_csums -= head->num_bytes;
2505                         spin_unlock(&delayed_refs->lock);
2506                 }
2507         }
2508
2509         if (head->must_insert_reserved) {
2510                 btrfs_pin_extent(fs_info, head->bytenr,
2511                                  head->num_bytes, 1);
2512                 if (head->is_data) {
2513                         ret = btrfs_del_csums(trans, fs_info, head->bytenr,
2514                                               head->num_bytes);
2515                 }
2516         }
2517
2518         /* Also free its reserved qgroup space */
2519         btrfs_qgroup_free_delayed_ref(fs_info, head->qgroup_ref_root,
2520                                       head->qgroup_reserved);
2521         btrfs_delayed_ref_unlock(head);
2522         btrfs_put_delayed_ref_head(head);
2523         return 0;
2524 }
2525
2526 static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
2527                                         struct btrfs_trans_handle *trans)
2528 {
2529         struct btrfs_delayed_ref_root *delayed_refs =
2530                 &trans->transaction->delayed_refs;
2531         struct btrfs_delayed_ref_head *head = NULL;
2532         int ret;
2533
2534         spin_lock(&delayed_refs->lock);
2535         head = btrfs_select_ref_head(delayed_refs);
2536         if (!head) {
2537                 spin_unlock(&delayed_refs->lock);
2538                 return head;
2539         }
2540
2541         /*
2542          * Grab the lock that says we are going to process all the refs for
2543          * this head
2544          */
2545         ret = btrfs_delayed_ref_lock(delayed_refs, head);
2546         spin_unlock(&delayed_refs->lock);
2547
2548         /*
2549          * We may have dropped the spin lock to get the head mutex lock, and
2550          * that might have given someone else time to free the head.  If that's
2551          * true, it has been removed from our list and we can move on.
2552          */
2553         if (ret == -EAGAIN)
2554                 head = ERR_PTR(-EAGAIN);
2555
2556         return head;
2557 }
2558
2559 static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
2560                                     struct btrfs_delayed_ref_head *locked_ref,
2561                                     unsigned long *run_refs)
2562 {
2563         struct btrfs_fs_info *fs_info = trans->fs_info;
2564         struct btrfs_delayed_ref_root *delayed_refs;
2565         struct btrfs_delayed_extent_op *extent_op;
2566         struct btrfs_delayed_ref_node *ref;
2567         int must_insert_reserved = 0;
2568         int ret;
2569
2570         delayed_refs = &trans->transaction->delayed_refs;
2571
2572         lockdep_assert_held(&locked_ref->mutex);
2573         lockdep_assert_held(&locked_ref->lock);
2574
2575         while ((ref = select_delayed_ref(locked_ref))) {
2576                 if (ref->seq &&
2577                     btrfs_check_delayed_seq(fs_info, ref->seq)) {
2578                         spin_unlock(&locked_ref->lock);
2579                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2580                         return -EAGAIN;
2581                 }
2582
2583                 (*run_refs)++;
2584                 ref->in_tree = 0;
2585                 rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
2586                 RB_CLEAR_NODE(&ref->ref_node);
2587                 if (!list_empty(&ref->add_list))
2588                         list_del(&ref->add_list);
2589                 /*
2590                  * When we play the delayed ref, also correct the ref_mod on
2591                  * head
2592                  */
2593                 switch (ref->action) {
2594                 case BTRFS_ADD_DELAYED_REF:
2595                 case BTRFS_ADD_DELAYED_EXTENT:
2596                         locked_ref->ref_mod -= ref->ref_mod;
2597                         break;
2598                 case BTRFS_DROP_DELAYED_REF:
2599                         locked_ref->ref_mod += ref->ref_mod;
2600                         break;
2601                 default:
2602                         WARN_ON(1);
2603                 }
2604                 atomic_dec(&delayed_refs->num_entries);
2605
2606                 /*
2607                  * Record the must_insert_reserved flag before we drop the
2608                  * spin lock.
2609                  */
2610                 must_insert_reserved = locked_ref->must_insert_reserved;
2611                 locked_ref->must_insert_reserved = 0;
2612
2613                 extent_op = locked_ref->extent_op;
2614                 locked_ref->extent_op = NULL;
2615                 spin_unlock(&locked_ref->lock);
2616
2617                 ret = run_one_delayed_ref(trans, ref, extent_op,
2618                                           must_insert_reserved);
2619
2620                 btrfs_free_delayed_extent_op(extent_op);
2621                 if (ret) {
2622                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2623                         btrfs_put_delayed_ref(ref);
2624                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
2625                                     ret);
2626                         return ret;
2627                 }
2628
2629                 btrfs_put_delayed_ref(ref);
2630                 cond_resched();
2631
2632                 spin_lock(&locked_ref->lock);
2633                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
2634         }
2635
2636         return 0;
2637 }
2638
2639 /*
2640  * Returns 0 on success or if called with an already aborted transaction.
2641  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2642  */
2643 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2644                                              unsigned long nr)
2645 {
2646         struct btrfs_fs_info *fs_info = trans->fs_info;
2647         struct btrfs_delayed_ref_root *delayed_refs;
2648         struct btrfs_delayed_ref_head *locked_ref = NULL;
2649         ktime_t start = ktime_get();
2650         int ret;
2651         unsigned long count = 0;
2652         unsigned long actual_count = 0;
2653
2654         delayed_refs = &trans->transaction->delayed_refs;
2655         do {
2656                 if (!locked_ref) {
2657                         locked_ref = btrfs_obtain_ref_head(trans);
2658                         if (IS_ERR_OR_NULL(locked_ref)) {
2659                                 if (PTR_ERR(locked_ref) == -EAGAIN) {
2660                                         continue;
2661                                 } else {
2662                                         break;
2663                                 }
2664                         }
2665                         count++;
2666                 }
2667                 /*
2668                  * We need to try and merge add/drops of the same ref since we
2669                  * can run into issues with relocate dropping the implicit ref
2670                  * and then it being added back again before the drop can
2671                  * finish.  If we merged anything we need to re-loop so we can
2672                  * get a good ref.
2673                  * Or we can get node references of the same type that weren't
2674                  * merged when created due to bumps in the tree mod seq, and
2675                  * we need to merge them to prevent adding an inline extent
2676                  * backref before dropping it (triggering a BUG_ON at
2677                  * insert_inline_extent_backref()).
2678                  */
2679                 spin_lock(&locked_ref->lock);
2680                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
2681
2682                 ret = btrfs_run_delayed_refs_for_head(trans, locked_ref,
2683                                                       &actual_count);
2684                 if (ret < 0 && ret != -EAGAIN) {
2685                         /*
2686                          * Error, btrfs_run_delayed_refs_for_head already
2687                          * unlocked everything so just bail out
2688                          */
2689                         return ret;
2690                 } else if (!ret) {
2691                         /*
2692                          * Success, perform the usual cleanup of a processed
2693                          * head
2694                          */
2695                         ret = cleanup_ref_head(trans, locked_ref);
2696                         if (ret > 0 ) {
2697                                 /* We dropped our lock, we need to loop. */
2698                                 ret = 0;
2699                                 continue;
2700                         } else if (ret) {
2701                                 return ret;
2702                         }
2703                 }
2704
2705                 /*
2706                  * Either success case or btrfs_run_delayed_refs_for_head
2707                  * returned -EAGAIN, meaning we need to select another head
2708                  */
2709
2710                 locked_ref = NULL;
2711                 cond_resched();
2712         } while ((nr != -1 && count < nr) || locked_ref);
2713
2714         /*
2715          * We don't want to include ref heads since we can have empty ref heads
2716          * and those will drastically skew our runtime down since we just do
2717          * accounting, no actual extent tree updates.
2718          */
2719         if (actual_count > 0) {
2720                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2721                 u64 avg;
2722
2723                 /*
2724                  * We weigh the current average higher than our current runtime
2725                  * to avoid large swings in the average.
2726                  */
2727                 spin_lock(&delayed_refs->lock);
2728                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2729                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2730                 spin_unlock(&delayed_refs->lock);
2731         }
2732         return 0;
2733 }
2734
2735 #ifdef SCRAMBLE_DELAYED_REFS
2736 /*
2737  * Normally delayed refs get processed in ascending bytenr order. This
2738  * correlates in most cases to the order added. To expose dependencies on this
2739  * order, we start to process the tree in the middle instead of the beginning
2740  */
2741 static u64 find_middle(struct rb_root *root)
2742 {
2743         struct rb_node *n = root->rb_node;
2744         struct btrfs_delayed_ref_node *entry;
2745         int alt = 1;
2746         u64 middle;
2747         u64 first = 0, last = 0;
2748
2749         n = rb_first(root);
2750         if (n) {
2751                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2752                 first = entry->bytenr;
2753         }
2754         n = rb_last(root);
2755         if (n) {
2756                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2757                 last = entry->bytenr;
2758         }
2759         n = root->rb_node;
2760
2761         while (n) {
2762                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2763                 WARN_ON(!entry->in_tree);
2764
2765                 middle = entry->bytenr;
2766
2767                 if (alt)
2768                         n = n->rb_left;
2769                 else
2770                         n = n->rb_right;
2771
2772                 alt = 1 - alt;
2773         }
2774         return middle;
2775 }
2776 #endif
2777
2778 static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
2779 {
2780         u64 num_bytes;
2781
2782         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2783                              sizeof(struct btrfs_extent_inline_ref));
2784         if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2785                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2786
2787         /*
2788          * We don't ever fill up leaves all the way so multiply by 2 just to be
2789          * closer to what we're really going to want to use.
2790          */
2791         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
2792 }
2793
2794 /*
2795  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2796  * would require to store the csums for that many bytes.
2797  */
2798 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2799 {
2800         u64 csum_size;
2801         u64 num_csums_per_leaf;
2802         u64 num_csums;
2803
2804         csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2805         num_csums_per_leaf = div64_u64(csum_size,
2806                         (u64)btrfs_super_csum_size(fs_info->super_copy));
2807         num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2808         num_csums += num_csums_per_leaf - 1;
2809         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2810         return num_csums;
2811 }
2812
2813 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans)
2814 {
2815         struct btrfs_fs_info *fs_info = trans->fs_info;
2816         struct btrfs_block_rsv *global_rsv;
2817         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2818         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2819         unsigned int num_dirty_bgs = trans->transaction->num_dirty_bgs;
2820         u64 num_bytes, num_dirty_bgs_bytes;
2821         int ret = 0;
2822
2823         num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
2824         num_heads = heads_to_leaves(fs_info, num_heads);
2825         if (num_heads > 1)
2826                 num_bytes += (num_heads - 1) * fs_info->nodesize;
2827         num_bytes <<= 1;
2828         num_bytes += btrfs_csum_bytes_to_leaves(fs_info, csum_bytes) *
2829                                                         fs_info->nodesize;
2830         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(fs_info,
2831                                                              num_dirty_bgs);
2832         global_rsv = &fs_info->global_block_rsv;
2833
2834         /*
2835          * If we can't allocate any more chunks lets make sure we have _lots_ of
2836          * wiggle room since running delayed refs can create more delayed refs.
2837          */
2838         if (global_rsv->space_info->full) {
2839                 num_dirty_bgs_bytes <<= 1;
2840                 num_bytes <<= 1;
2841         }
2842
2843         spin_lock(&global_rsv->lock);
2844         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2845                 ret = 1;
2846         spin_unlock(&global_rsv->lock);
2847         return ret;
2848 }
2849
2850 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans)
2851 {
2852         u64 num_entries =
2853                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2854         u64 avg_runtime;
2855         u64 val;
2856
2857         smp_mb();
2858         avg_runtime = trans->fs_info->avg_delayed_ref_runtime;
2859         val = num_entries * avg_runtime;
2860         if (val >= NSEC_PER_SEC)
2861                 return 1;
2862         if (val >= NSEC_PER_SEC / 2)
2863                 return 2;
2864
2865         return btrfs_check_space_for_delayed_refs(trans);
2866 }
2867
2868 struct async_delayed_refs {
2869         struct btrfs_root *root;
2870         u64 transid;
2871         int count;
2872         int error;
2873         int sync;
2874         struct completion wait;
2875         struct btrfs_work work;
2876 };
2877
2878 static inline struct async_delayed_refs *
2879 to_async_delayed_refs(struct btrfs_work *work)
2880 {
2881         return container_of(work, struct async_delayed_refs, work);
2882 }
2883
2884 static void delayed_ref_async_start(struct btrfs_work *work)
2885 {
2886         struct async_delayed_refs *async = to_async_delayed_refs(work);
2887         struct btrfs_trans_handle *trans;
2888         struct btrfs_fs_info *fs_info = async->root->fs_info;
2889         int ret;
2890
2891         /* if the commit is already started, we don't need to wait here */
2892         if (btrfs_transaction_blocked(fs_info))
2893                 goto done;
2894
2895         trans = btrfs_join_transaction(async->root);
2896         if (IS_ERR(trans)) {
2897                 async->error = PTR_ERR(trans);
2898                 goto done;
2899         }
2900
2901         /*
2902          * trans->sync means that when we call end_transaction, we won't
2903          * wait on delayed refs
2904          */
2905         trans->sync = true;
2906
2907         /* Don't bother flushing if we got into a different transaction */
2908         if (trans->transid > async->transid)
2909                 goto end;
2910
2911         ret = btrfs_run_delayed_refs(trans, async->count);
2912         if (ret)
2913                 async->error = ret;
2914 end:
2915         ret = btrfs_end_transaction(trans);
2916         if (ret && !async->error)
2917                 async->error = ret;
2918 done:
2919         if (async->sync)
2920                 complete(&async->wait);
2921         else
2922                 kfree(async);
2923 }
2924
2925 int btrfs_async_run_delayed_refs(struct btrfs_fs_info *fs_info,
2926                                  unsigned long count, u64 transid, int wait)
2927 {
2928         struct async_delayed_refs *async;
2929         int ret;
2930
2931         async = kmalloc(sizeof(*async), GFP_NOFS);
2932         if (!async)
2933                 return -ENOMEM;
2934
2935         async->root = fs_info->tree_root;
2936         async->count = count;
2937         async->error = 0;
2938         async->transid = transid;
2939         if (wait)
2940                 async->sync = 1;
2941         else
2942                 async->sync = 0;
2943         init_completion(&async->wait);
2944
2945         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2946                         delayed_ref_async_start, NULL, NULL);
2947
2948         btrfs_queue_work(fs_info->extent_workers, &async->work);
2949
2950         if (wait) {
2951                 wait_for_completion(&async->wait);
2952                 ret = async->error;
2953                 kfree(async);
2954                 return ret;
2955         }
2956         return 0;
2957 }
2958
2959 /*
2960  * this starts processing the delayed reference count updates and
2961  * extent insertions we have queued up so far.  count can be
2962  * 0, which means to process everything in the tree at the start
2963  * of the run (but not newly added entries), or it can be some target
2964  * number you'd like to process.
2965  *
2966  * Returns 0 on success or if called with an aborted transaction
2967  * Returns <0 on error and aborts the transaction
2968  */
2969 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2970                            unsigned long count)
2971 {
2972         struct btrfs_fs_info *fs_info = trans->fs_info;
2973         struct rb_node *node;
2974         struct btrfs_delayed_ref_root *delayed_refs;
2975         struct btrfs_delayed_ref_head *head;
2976         int ret;
2977         int run_all = count == (unsigned long)-1;
2978
2979         /* We'll clean this up in btrfs_cleanup_transaction */
2980         if (trans->aborted)
2981                 return 0;
2982
2983         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
2984                 return 0;
2985
2986         delayed_refs = &trans->transaction->delayed_refs;
2987         if (count == 0)
2988                 count = atomic_read(&delayed_refs->num_entries) * 2;
2989
2990 again:
2991 #ifdef SCRAMBLE_DELAYED_REFS
2992         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2993 #endif
2994         ret = __btrfs_run_delayed_refs(trans, count);
2995         if (ret < 0) {
2996                 btrfs_abort_transaction(trans, ret);
2997                 return ret;
2998         }
2999
3000         if (run_all) {
3001                 if (!list_empty(&trans->new_bgs))
3002                         btrfs_create_pending_block_groups(trans);
3003
3004                 spin_lock(&delayed_refs->lock);
3005                 node = rb_first_cached(&delayed_refs->href_root);
3006                 if (!node) {
3007                         spin_unlock(&delayed_refs->lock);
3008                         goto out;
3009                 }
3010                 head = rb_entry(node, struct btrfs_delayed_ref_head,
3011                                 href_node);
3012                 refcount_inc(&head->refs);
3013                 spin_unlock(&delayed_refs->lock);
3014
3015                 /* Mutex was contended, block until it's released and retry. */
3016                 mutex_lock(&head->mutex);
3017                 mutex_unlock(&head->mutex);
3018
3019                 btrfs_put_delayed_ref_head(head);
3020                 cond_resched();
3021                 goto again;
3022         }
3023 out:
3024         return 0;
3025 }
3026
3027 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3028                                 struct btrfs_fs_info *fs_info,
3029                                 u64 bytenr, u64 num_bytes, u64 flags,
3030                                 int level, int is_data)
3031 {
3032         struct btrfs_delayed_extent_op *extent_op;
3033         int ret;
3034
3035         extent_op = btrfs_alloc_delayed_extent_op();
3036         if (!extent_op)
3037                 return -ENOMEM;
3038
3039         extent_op->flags_to_set = flags;
3040         extent_op->update_flags = true;
3041         extent_op->update_key = false;
3042         extent_op->is_data = is_data ? true : false;
3043         extent_op->level = level;
3044
3045         ret = btrfs_add_delayed_extent_op(fs_info, trans, bytenr,
3046                                           num_bytes, extent_op);
3047         if (ret)
3048                 btrfs_free_delayed_extent_op(extent_op);
3049         return ret;
3050 }
3051
3052 static noinline int check_delayed_ref(struct btrfs_root *root,
3053                                       struct btrfs_path *path,
3054                                       u64 objectid, u64 offset, u64 bytenr)
3055 {
3056         struct btrfs_delayed_ref_head *head;
3057         struct btrfs_delayed_ref_node *ref;
3058         struct btrfs_delayed_data_ref *data_ref;
3059         struct btrfs_delayed_ref_root *delayed_refs;
3060         struct btrfs_transaction *cur_trans;
3061         struct rb_node *node;
3062         int ret = 0;
3063
3064         spin_lock(&root->fs_info->trans_lock);
3065         cur_trans = root->fs_info->running_transaction;
3066         if (cur_trans)
3067                 refcount_inc(&cur_trans->use_count);
3068         spin_unlock(&root->fs_info->trans_lock);
3069         if (!cur_trans)
3070                 return 0;
3071
3072         delayed_refs = &cur_trans->delayed_refs;
3073         spin_lock(&delayed_refs->lock);
3074         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3075         if (!head) {
3076                 spin_unlock(&delayed_refs->lock);
3077                 btrfs_put_transaction(cur_trans);
3078                 return 0;
3079         }
3080
3081         if (!mutex_trylock(&head->mutex)) {
3082                 refcount_inc(&head->refs);
3083                 spin_unlock(&delayed_refs->lock);
3084
3085                 btrfs_release_path(path);
3086
3087                 /*
3088                  * Mutex was contended, block until it's released and let
3089                  * caller try again
3090                  */
3091                 mutex_lock(&head->mutex);
3092                 mutex_unlock(&head->mutex);
3093                 btrfs_put_delayed_ref_head(head);
3094                 btrfs_put_transaction(cur_trans);
3095                 return -EAGAIN;
3096         }
3097         spin_unlock(&delayed_refs->lock);
3098
3099         spin_lock(&head->lock);
3100         /*
3101          * XXX: We should replace this with a proper search function in the
3102          * future.
3103          */
3104         for (node = rb_first_cached(&head->ref_tree); node;
3105              node = rb_next(node)) {
3106                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
3107                 /* If it's a shared ref we know a cross reference exists */
3108                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3109                         ret = 1;
3110                         break;
3111                 }
3112
3113                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3114
3115                 /*
3116                  * If our ref doesn't match the one we're currently looking at
3117                  * then we have a cross reference.
3118                  */
3119                 if (data_ref->root != root->root_key.objectid ||
3120                     data_ref->objectid != objectid ||
3121                     data_ref->offset != offset) {
3122                         ret = 1;
3123                         break;
3124                 }
3125         }
3126         spin_unlock(&head->lock);
3127         mutex_unlock(&head->mutex);
3128         btrfs_put_transaction(cur_trans);
3129         return ret;
3130 }
3131
3132 static noinline int check_committed_ref(struct btrfs_root *root,
3133                                         struct btrfs_path *path,
3134                                         u64 objectid, u64 offset, u64 bytenr)
3135 {
3136         struct btrfs_fs_info *fs_info = root->fs_info;
3137         struct btrfs_root *extent_root = fs_info->extent_root;
3138         struct extent_buffer *leaf;
3139         struct btrfs_extent_data_ref *ref;
3140         struct btrfs_extent_inline_ref *iref;
3141         struct btrfs_extent_item *ei;
3142         struct btrfs_key key;
3143         u32 item_size;
3144         int type;
3145         int ret;
3146
3147         key.objectid = bytenr;
3148         key.offset = (u64)-1;
3149         key.type = BTRFS_EXTENT_ITEM_KEY;
3150
3151         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3152         if (ret < 0)
3153                 goto out;
3154         BUG_ON(ret == 0); /* Corruption */
3155
3156         ret = -ENOENT;
3157         if (path->slots[0] == 0)
3158                 goto out;
3159
3160         path->slots[0]--;
3161         leaf = path->nodes[0];
3162         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3163
3164         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3165                 goto out;
3166
3167         ret = 1;
3168         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3169         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3170
3171         if (item_size != sizeof(*ei) +
3172             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3173                 goto out;
3174
3175         if (btrfs_extent_generation(leaf, ei) <=
3176             btrfs_root_last_snapshot(&root->root_item))
3177                 goto out;
3178
3179         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3180
3181         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
3182         if (type != BTRFS_EXTENT_DATA_REF_KEY)
3183                 goto out;
3184
3185         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3186         if (btrfs_extent_refs(leaf, ei) !=
3187             btrfs_extent_data_ref_count(leaf, ref) ||
3188             btrfs_extent_data_ref_root(leaf, ref) !=
3189             root->root_key.objectid ||
3190             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3191             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3192                 goto out;
3193
3194         ret = 0;
3195 out:
3196         return ret;
3197 }
3198
3199 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
3200                           u64 bytenr)
3201 {
3202         struct btrfs_path *path;
3203         int ret;
3204
3205         path = btrfs_alloc_path();
3206         if (!path)
3207                 return -ENOMEM;
3208
3209         do {
3210                 ret = check_committed_ref(root, path, objectid,
3211                                           offset, bytenr);
3212                 if (ret && ret != -ENOENT)
3213                         goto out;
3214
3215                 ret = check_delayed_ref(root, path, objectid, offset, bytenr);
3216         } while (ret == -EAGAIN);
3217
3218 out:
3219         btrfs_free_path(path);
3220         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3221                 WARN_ON(ret > 0);
3222         return ret;
3223 }
3224
3225 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3226                            struct btrfs_root *root,
3227                            struct extent_buffer *buf,
3228                            int full_backref, int inc)
3229 {
3230         struct btrfs_fs_info *fs_info = root->fs_info;
3231         u64 bytenr;
3232         u64 num_bytes;
3233         u64 parent;
3234         u64 ref_root;
3235         u32 nritems;
3236         struct btrfs_key key;
3237         struct btrfs_file_extent_item *fi;
3238         int i;
3239         int level;
3240         int ret = 0;
3241         int (*process_func)(struct btrfs_trans_handle *,
3242                             struct btrfs_root *,
3243                             u64, u64, u64, u64, u64, u64);
3244
3245
3246         if (btrfs_is_testing(fs_info))
3247                 return 0;
3248
3249         ref_root = btrfs_header_owner(buf);
3250         nritems = btrfs_header_nritems(buf);
3251         level = btrfs_header_level(buf);
3252
3253         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3254                 return 0;
3255
3256         if (inc)
3257                 process_func = btrfs_inc_extent_ref;
3258         else
3259                 process_func = btrfs_free_extent;
3260
3261         if (full_backref)
3262                 parent = buf->start;
3263         else
3264                 parent = 0;
3265
3266         for (i = 0; i < nritems; i++) {
3267                 if (level == 0) {
3268                         btrfs_item_key_to_cpu(buf, &key, i);
3269                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3270                                 continue;
3271                         fi = btrfs_item_ptr(buf, i,
3272                                             struct btrfs_file_extent_item);
3273                         if (btrfs_file_extent_type(buf, fi) ==
3274                             BTRFS_FILE_EXTENT_INLINE)
3275                                 continue;
3276                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3277                         if (bytenr == 0)
3278                                 continue;
3279
3280                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3281                         key.offset -= btrfs_file_extent_offset(buf, fi);
3282                         ret = process_func(trans, root, bytenr, num_bytes,
3283                                            parent, ref_root, key.objectid,
3284                                            key.offset);
3285                         if (ret)
3286                                 goto fail;
3287                 } else {
3288                         bytenr = btrfs_node_blockptr(buf, i);
3289                         num_bytes = fs_info->nodesize;
3290                         ret = process_func(trans, root, bytenr, num_bytes,
3291                                            parent, ref_root, level - 1, 0);
3292                         if (ret)
3293                                 goto fail;
3294                 }
3295         }
3296         return 0;
3297 fail:
3298         return ret;
3299 }
3300
3301 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3302                   struct extent_buffer *buf, int full_backref)
3303 {
3304         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3305 }
3306
3307 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3308                   struct extent_buffer *buf, int full_backref)
3309 {
3310         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3311 }
3312
3313 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3314                                  struct btrfs_fs_info *fs_info,
3315                                  struct btrfs_path *path,
3316                                  struct btrfs_block_group_cache *cache)
3317 {
3318         int ret;
3319         struct btrfs_root *extent_root = fs_info->extent_root;
3320         unsigned long bi;
3321         struct extent_buffer *leaf;
3322
3323         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3324         if (ret) {
3325                 if (ret > 0)
3326                         ret = -ENOENT;
3327                 goto fail;
3328         }
3329
3330         leaf = path->nodes[0];
3331         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3332         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3333         btrfs_mark_buffer_dirty(leaf);
3334 fail:
3335         btrfs_release_path(path);
3336         return ret;
3337
3338 }
3339
3340 static struct btrfs_block_group_cache *
3341 next_block_group(struct btrfs_fs_info *fs_info,
3342                  struct btrfs_block_group_cache *cache)
3343 {
3344         struct rb_node *node;
3345
3346         spin_lock(&fs_info->block_group_cache_lock);
3347
3348         /* If our block group was removed, we need a full search. */
3349         if (RB_EMPTY_NODE(&cache->cache_node)) {
3350                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3351
3352                 spin_unlock(&fs_info->block_group_cache_lock);
3353                 btrfs_put_block_group(cache);
3354                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
3355         }
3356         node = rb_next(&cache->cache_node);
3357         btrfs_put_block_group(cache);
3358         if (node) {
3359                 cache = rb_entry(node, struct btrfs_block_group_cache,
3360                                  cache_node);
3361                 btrfs_get_block_group(cache);
3362         } else
3363                 cache = NULL;
3364         spin_unlock(&fs_info->block_group_cache_lock);
3365         return cache;
3366 }
3367
3368 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3369                             struct btrfs_trans_handle *trans,
3370                             struct btrfs_path *path)
3371 {
3372         struct btrfs_fs_info *fs_info = block_group->fs_info;
3373         struct btrfs_root *root = fs_info->tree_root;
3374         struct inode *inode = NULL;
3375         struct extent_changeset *data_reserved = NULL;
3376         u64 alloc_hint = 0;
3377         int dcs = BTRFS_DC_ERROR;
3378         u64 num_pages = 0;
3379         int retries = 0;
3380         int ret = 0;
3381
3382         /*
3383          * If this block group is smaller than 100 megs don't bother caching the
3384          * block group.
3385          */
3386         if (block_group->key.offset < (100 * SZ_1M)) {
3387                 spin_lock(&block_group->lock);
3388                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3389                 spin_unlock(&block_group->lock);
3390                 return 0;
3391         }
3392
3393         if (trans->aborted)
3394                 return 0;
3395 again:
3396         inode = lookup_free_space_inode(fs_info, block_group, path);
3397         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3398                 ret = PTR_ERR(inode);
3399                 btrfs_release_path(path);
3400                 goto out;
3401         }
3402
3403         if (IS_ERR(inode)) {
3404                 BUG_ON(retries);
3405                 retries++;
3406
3407                 if (block_group->ro)
3408                         goto out_free;
3409
3410                 ret = create_free_space_inode(fs_info, trans, block_group,
3411                                               path);
3412                 if (ret)
3413                         goto out_free;
3414                 goto again;
3415         }
3416
3417         /*
3418          * We want to set the generation to 0, that way if anything goes wrong
3419          * from here on out we know not to trust this cache when we load up next
3420          * time.
3421          */
3422         BTRFS_I(inode)->generation = 0;
3423         ret = btrfs_update_inode(trans, root, inode);
3424         if (ret) {
3425                 /*
3426                  * So theoretically we could recover from this, simply set the
3427                  * super cache generation to 0 so we know to invalidate the
3428                  * cache, but then we'd have to keep track of the block groups
3429                  * that fail this way so we know we _have_ to reset this cache
3430                  * before the next commit or risk reading stale cache.  So to
3431                  * limit our exposure to horrible edge cases lets just abort the
3432                  * transaction, this only happens in really bad situations
3433                  * anyway.
3434                  */
3435                 btrfs_abort_transaction(trans, ret);
3436                 goto out_put;
3437         }
3438         WARN_ON(ret);
3439
3440         /* We've already setup this transaction, go ahead and exit */
3441         if (block_group->cache_generation == trans->transid &&
3442             i_size_read(inode)) {
3443                 dcs = BTRFS_DC_SETUP;
3444                 goto out_put;
3445         }
3446
3447         if (i_size_read(inode) > 0) {
3448                 ret = btrfs_check_trunc_cache_free_space(fs_info,
3449                                         &fs_info->global_block_rsv);
3450                 if (ret)
3451                         goto out_put;
3452
3453                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3454                 if (ret)
3455                         goto out_put;
3456         }
3457
3458         spin_lock(&block_group->lock);
3459         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3460             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3461                 /*
3462                  * don't bother trying to write stuff out _if_
3463                  * a) we're not cached,
3464                  * b) we're with nospace_cache mount option,
3465                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
3466                  */
3467                 dcs = BTRFS_DC_WRITTEN;
3468                 spin_unlock(&block_group->lock);
3469                 goto out_put;
3470         }
3471         spin_unlock(&block_group->lock);
3472
3473         /*
3474          * We hit an ENOSPC when setting up the cache in this transaction, just
3475          * skip doing the setup, we've already cleared the cache so we're safe.
3476          */
3477         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3478                 ret = -ENOSPC;
3479                 goto out_put;
3480         }
3481
3482         /*
3483          * Try to preallocate enough space based on how big the block group is.
3484          * Keep in mind this has to include any pinned space which could end up
3485          * taking up quite a bit since it's not folded into the other space
3486          * cache.
3487          */
3488         num_pages = div_u64(block_group->key.offset, SZ_256M);
3489         if (!num_pages)
3490                 num_pages = 1;
3491
3492         num_pages *= 16;
3493         num_pages *= PAGE_SIZE;
3494
3495         ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
3496         if (ret)
3497                 goto out_put;
3498
3499         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3500                                               num_pages, num_pages,
3501                                               &alloc_hint);
3502         /*
3503          * Our cache requires contiguous chunks so that we don't modify a bunch
3504          * of metadata or split extents when writing the cache out, which means
3505          * we can enospc if we are heavily fragmented in addition to just normal
3506          * out of space conditions.  So if we hit this just skip setting up any
3507          * other block groups for this transaction, maybe we'll unpin enough
3508          * space the next time around.
3509          */
3510         if (!ret)
3511                 dcs = BTRFS_DC_SETUP;
3512         else if (ret == -ENOSPC)
3513                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3514
3515 out_put:
3516         iput(inode);
3517 out_free:
3518         btrfs_release_path(path);
3519 out:
3520         spin_lock(&block_group->lock);
3521         if (!ret && dcs == BTRFS_DC_SETUP)
3522                 block_group->cache_generation = trans->transid;
3523         block_group->disk_cache_state = dcs;
3524         spin_unlock(&block_group->lock);
3525
3526         extent_changeset_free(data_reserved);
3527         return ret;
3528 }
3529
3530 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3531                             struct btrfs_fs_info *fs_info)
3532 {
3533         struct btrfs_block_group_cache *cache, *tmp;
3534         struct btrfs_transaction *cur_trans = trans->transaction;
3535         struct btrfs_path *path;
3536
3537         if (list_empty(&cur_trans->dirty_bgs) ||
3538             !btrfs_test_opt(fs_info, SPACE_CACHE))
3539                 return 0;
3540
3541         path = btrfs_alloc_path();
3542         if (!path)
3543                 return -ENOMEM;
3544
3545         /* Could add new block groups, use _safe just in case */
3546         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3547                                  dirty_list) {
3548                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3549                         cache_save_setup(cache, trans, path);
3550         }
3551
3552         btrfs_free_path(path);
3553         return 0;
3554 }
3555
3556 /*
3557  * transaction commit does final block group cache writeback during a
3558  * critical section where nothing is allowed to change the FS.  This is
3559  * required in order for the cache to actually match the block group,
3560  * but can introduce a lot of latency into the commit.
3561  *
3562  * So, btrfs_start_dirty_block_groups is here to kick off block group
3563  * cache IO.  There's a chance we'll have to redo some of it if the
3564  * block group changes again during the commit, but it greatly reduces
3565  * the commit latency by getting rid of the easy block groups while
3566  * we're still allowing others to join the commit.
3567  */
3568 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
3569 {
3570         struct btrfs_fs_info *fs_info = trans->fs_info;
3571         struct btrfs_block_group_cache *cache;
3572         struct btrfs_transaction *cur_trans = trans->transaction;
3573         int ret = 0;
3574         int should_put;
3575         struct btrfs_path *path = NULL;
3576         LIST_HEAD(dirty);
3577         struct list_head *io = &cur_trans->io_bgs;
3578         int num_started = 0;
3579         int loops = 0;
3580
3581         spin_lock(&cur_trans->dirty_bgs_lock);
3582         if (list_empty(&cur_trans->dirty_bgs)) {
3583                 spin_unlock(&cur_trans->dirty_bgs_lock);
3584                 return 0;
3585         }
3586         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3587         spin_unlock(&cur_trans->dirty_bgs_lock);
3588
3589 again:
3590         /*
3591          * make sure all the block groups on our dirty list actually
3592          * exist
3593          */
3594         btrfs_create_pending_block_groups(trans);
3595
3596         if (!path) {
3597                 path = btrfs_alloc_path();
3598                 if (!path)
3599                         return -ENOMEM;
3600         }
3601
3602         /*
3603          * cache_write_mutex is here only to save us from balance or automatic
3604          * removal of empty block groups deleting this block group while we are
3605          * writing out the cache
3606          */
3607         mutex_lock(&trans->transaction->cache_write_mutex);
3608         while (!list_empty(&dirty)) {
3609                 cache = list_first_entry(&dirty,
3610                                          struct btrfs_block_group_cache,
3611                                          dirty_list);
3612                 /*
3613                  * this can happen if something re-dirties a block
3614                  * group that is already under IO.  Just wait for it to
3615                  * finish and then do it all again
3616                  */
3617                 if (!list_empty(&cache->io_list)) {
3618                         list_del_init(&cache->io_list);
3619                         btrfs_wait_cache_io(trans, cache, path);
3620                         btrfs_put_block_group(cache);
3621                 }
3622
3623
3624                 /*
3625                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3626                  * if it should update the cache_state.  Don't delete
3627                  * until after we wait.
3628                  *
3629                  * Since we're not running in the commit critical section
3630                  * we need the dirty_bgs_lock to protect from update_block_group
3631                  */
3632                 spin_lock(&cur_trans->dirty_bgs_lock);
3633                 list_del_init(&cache->dirty_list);
3634                 spin_unlock(&cur_trans->dirty_bgs_lock);
3635
3636                 should_put = 1;
3637
3638                 cache_save_setup(cache, trans, path);
3639
3640                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3641                         cache->io_ctl.inode = NULL;
3642                         ret = btrfs_write_out_cache(fs_info, trans,
3643                                                     cache, path);
3644                         if (ret == 0 && cache->io_ctl.inode) {
3645                                 num_started++;
3646                                 should_put = 0;
3647
3648                                 /*
3649                                  * The cache_write_mutex is protecting the
3650                                  * io_list, also refer to the definition of
3651                                  * btrfs_transaction::io_bgs for more details
3652                                  */
3653                                 list_add_tail(&cache->io_list, io);
3654                         } else {
3655                                 /*
3656                                  * if we failed to write the cache, the
3657                                  * generation will be bad and life goes on
3658                                  */
3659                                 ret = 0;
3660                         }
3661                 }
3662                 if (!ret) {
3663                         ret = write_one_cache_group(trans, fs_info,
3664                                                     path, cache);
3665                         /*
3666                          * Our block group might still be attached to the list
3667                          * of new block groups in the transaction handle of some
3668                          * other task (struct btrfs_trans_handle->new_bgs). This
3669                          * means its block group item isn't yet in the extent
3670                          * tree. If this happens ignore the error, as we will
3671                          * try again later in the critical section of the
3672                          * transaction commit.
3673                          */
3674                         if (ret == -ENOENT) {
3675                                 ret = 0;
3676                                 spin_lock(&cur_trans->dirty_bgs_lock);
3677                                 if (list_empty(&cache->dirty_list)) {
3678                                         list_add_tail(&cache->dirty_list,
3679                                                       &cur_trans->dirty_bgs);
3680                                         btrfs_get_block_group(cache);
3681                                 }
3682                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3683                         } else if (ret) {
3684                                 btrfs_abort_transaction(trans, ret);
3685                         }
3686                 }
3687
3688                 /* if its not on the io list, we need to put the block group */
3689                 if (should_put)
3690                         btrfs_put_block_group(cache);
3691
3692                 if (ret)
3693                         break;
3694
3695                 /*
3696                  * Avoid blocking other tasks for too long. It might even save
3697                  * us from writing caches for block groups that are going to be
3698                  * removed.
3699                  */
3700                 mutex_unlock(&trans->transaction->cache_write_mutex);
3701                 mutex_lock(&trans->transaction->cache_write_mutex);
3702         }
3703         mutex_unlock(&trans->transaction->cache_write_mutex);
3704
3705         /*
3706          * go through delayed refs for all the stuff we've just kicked off
3707          * and then loop back (just once)
3708          */
3709         ret = btrfs_run_delayed_refs(trans, 0);
3710         if (!ret && loops == 0) {
3711                 loops++;
3712                 spin_lock(&cur_trans->dirty_bgs_lock);
3713                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3714                 /*
3715                  * dirty_bgs_lock protects us from concurrent block group
3716                  * deletes too (not just cache_write_mutex).
3717                  */
3718                 if (!list_empty(&dirty)) {
3719                         spin_unlock(&cur_trans->dirty_bgs_lock);
3720                         goto again;
3721                 }
3722                 spin_unlock(&cur_trans->dirty_bgs_lock);
3723         } else if (ret < 0) {
3724                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3725         }
3726
3727         btrfs_free_path(path);
3728         return ret;
3729 }
3730
3731 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3732                                    struct btrfs_fs_info *fs_info)
3733 {
3734         struct btrfs_block_group_cache *cache;
3735         struct btrfs_transaction *cur_trans = trans->transaction;
3736         int ret = 0;
3737         int should_put;
3738         struct btrfs_path *path;
3739         struct list_head *io = &cur_trans->io_bgs;
3740         int num_started = 0;
3741
3742         path = btrfs_alloc_path();
3743         if (!path)
3744                 return -ENOMEM;
3745
3746         /*
3747          * Even though we are in the critical section of the transaction commit,
3748          * we can still have concurrent tasks adding elements to this
3749          * transaction's list of dirty block groups. These tasks correspond to
3750          * endio free space workers started when writeback finishes for a
3751          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3752          * allocate new block groups as a result of COWing nodes of the root
3753          * tree when updating the free space inode. The writeback for the space
3754          * caches is triggered by an earlier call to
3755          * btrfs_start_dirty_block_groups() and iterations of the following
3756          * loop.
3757          * Also we want to do the cache_save_setup first and then run the
3758          * delayed refs to make sure we have the best chance at doing this all
3759          * in one shot.
3760          */
3761         spin_lock(&cur_trans->dirty_bgs_lock);
3762         while (!list_empty(&cur_trans->dirty_bgs)) {
3763                 cache = list_first_entry(&cur_trans->dirty_bgs,
3764                                          struct btrfs_block_group_cache,
3765                                          dirty_list);
3766
3767                 /*
3768                  * this can happen if cache_save_setup re-dirties a block
3769                  * group that is already under IO.  Just wait for it to
3770                  * finish and then do it all again
3771                  */
3772                 if (!list_empty(&cache->io_list)) {
3773                         spin_unlock(&cur_trans->dirty_bgs_lock);
3774                         list_del_init(&cache->io_list);
3775                         btrfs_wait_cache_io(trans, cache, path);
3776                         btrfs_put_block_group(cache);
3777                         spin_lock(&cur_trans->dirty_bgs_lock);
3778                 }
3779
3780                 /*
3781                  * don't remove from the dirty list until after we've waited
3782                  * on any pending IO
3783                  */
3784                 list_del_init(&cache->dirty_list);
3785                 spin_unlock(&cur_trans->dirty_bgs_lock);
3786                 should_put = 1;
3787
3788                 cache_save_setup(cache, trans, path);
3789
3790                 if (!ret)
3791                         ret = btrfs_run_delayed_refs(trans,
3792                                                      (unsigned long) -1);
3793
3794                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3795                         cache->io_ctl.inode = NULL;
3796                         ret = btrfs_write_out_cache(fs_info, trans,
3797                                                     cache, path);
3798                         if (ret == 0 && cache->io_ctl.inode) {
3799                                 num_started++;
3800                                 should_put = 0;
3801                                 list_add_tail(&cache->io_list, io);
3802                         } else {
3803                                 /*
3804                                  * if we failed to write the cache, the
3805                                  * generation will be bad and life goes on
3806                                  */
3807                                 ret = 0;
3808                         }
3809                 }
3810                 if (!ret) {
3811                         ret = write_one_cache_group(trans, fs_info,
3812                                                     path, cache);
3813                         /*
3814                          * One of the free space endio workers might have
3815                          * created a new block group while updating a free space
3816                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3817                          * and hasn't released its transaction handle yet, in
3818                          * which case the new block group is still attached to
3819                          * its transaction handle and its creation has not
3820                          * finished yet (no block group item in the extent tree
3821                          * yet, etc). If this is the case, wait for all free
3822                          * space endio workers to finish and retry. This is a
3823                          * a very rare case so no need for a more efficient and
3824                          * complex approach.
3825                          */
3826                         if (ret == -ENOENT) {
3827                                 wait_event(cur_trans->writer_wait,
3828                                    atomic_read(&cur_trans->num_writers) == 1);
3829                                 ret = write_one_cache_group(trans, fs_info,
3830                                                             path, cache);
3831                         }
3832                         if (ret)
3833                                 btrfs_abort_transaction(trans, ret);
3834                 }
3835
3836                 /* if its not on the io list, we need to put the block group */
3837                 if (should_put)
3838                         btrfs_put_block_group(cache);
3839                 spin_lock(&cur_trans->dirty_bgs_lock);
3840         }
3841         spin_unlock(&cur_trans->dirty_bgs_lock);
3842
3843         /*
3844          * Refer to the definition of io_bgs member for details why it's safe
3845          * to use it without any locking
3846          */
3847         while (!list_empty(io)) {
3848                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3849                                          io_list);
3850                 list_del_init(&cache->io_list);
3851                 btrfs_wait_cache_io(trans, cache, path);
3852                 btrfs_put_block_group(cache);
3853         }
3854
3855         btrfs_free_path(path);
3856         return ret;
3857 }
3858
3859 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
3860 {
3861         struct btrfs_block_group_cache *block_group;
3862         int readonly = 0;
3863
3864         block_group = btrfs_lookup_block_group(fs_info, bytenr);
3865         if (!block_group || block_group->ro)
3866                 readonly = 1;
3867         if (block_group)
3868                 btrfs_put_block_group(block_group);
3869         return readonly;
3870 }
3871
3872 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3873 {
3874         struct btrfs_block_group_cache *bg;
3875         bool ret = true;
3876
3877         bg = btrfs_lookup_block_group(fs_info, bytenr);
3878         if (!bg)
3879                 return false;
3880
3881         spin_lock(&bg->lock);
3882         if (bg->ro)
3883                 ret = false;
3884         else
3885                 atomic_inc(&bg->nocow_writers);
3886         spin_unlock(&bg->lock);
3887
3888         /* no put on block group, done by btrfs_dec_nocow_writers */
3889         if (!ret)
3890                 btrfs_put_block_group(bg);
3891
3892         return ret;
3893
3894 }
3895
3896 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3897 {
3898         struct btrfs_block_group_cache *bg;
3899
3900         bg = btrfs_lookup_block_group(fs_info, bytenr);
3901         ASSERT(bg);
3902         if (atomic_dec_and_test(&bg->nocow_writers))
3903                 wake_up_var(&bg->nocow_writers);
3904         /*
3905          * Once for our lookup and once for the lookup done by a previous call
3906          * to btrfs_inc_nocow_writers()
3907          */
3908         btrfs_put_block_group(bg);
3909         btrfs_put_block_group(bg);
3910 }
3911
3912 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3913 {
3914         wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
3915 }
3916
3917 static const char *alloc_name(u64 flags)
3918 {
3919         switch (flags) {
3920         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3921                 return "mixed";
3922         case BTRFS_BLOCK_GROUP_METADATA:
3923                 return "metadata";
3924         case BTRFS_BLOCK_GROUP_DATA:
3925                 return "data";
3926         case BTRFS_BLOCK_GROUP_SYSTEM:
3927                 return "system";
3928         default:
3929                 WARN_ON(1);
3930                 return "invalid-combination";
3931         };
3932 }
3933
3934 static int create_space_info(struct btrfs_fs_info *info, u64 flags)
3935 {
3936
3937         struct btrfs_space_info *space_info;
3938         int i;
3939         int ret;
3940
3941         space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
3942         if (!space_info)
3943                 return -ENOMEM;
3944
3945         ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
3946                                  GFP_KERNEL);
3947         if (ret) {
3948                 kfree(space_info);
3949                 return ret;
3950         }
3951
3952         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3953                 INIT_LIST_HEAD(&space_info->block_groups[i]);
3954         init_rwsem(&space_info->groups_sem);
3955         spin_lock_init(&space_info->lock);
3956         space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3957         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3958         init_waitqueue_head(&space_info->wait);
3959         INIT_LIST_HEAD(&space_info->ro_bgs);
3960         INIT_LIST_HEAD(&space_info->tickets);
3961         INIT_LIST_HEAD(&space_info->priority_tickets);
3962
3963         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
3964                                     info->space_info_kobj, "%s",
3965                                     alloc_name(space_info->flags));
3966         if (ret) {
3967                 percpu_counter_destroy(&space_info->total_bytes_pinned);
3968                 kfree(space_info);
3969                 return ret;
3970         }
3971
3972         list_add_rcu(&space_info->list, &info->space_info);
3973         if (flags & BTRFS_BLOCK_GROUP_DATA)
3974                 info->data_sinfo = space_info;
3975
3976         return ret;
3977 }
3978
3979 static void update_space_info(struct btrfs_fs_info *info, u64 flags,
3980                              u64 total_bytes, u64 bytes_used,
3981                              u64 bytes_readonly,
3982                              struct btrfs_space_info **space_info)
3983 {
3984         struct btrfs_space_info *found;
3985         int factor;
3986
3987         factor = btrfs_bg_type_to_factor(flags);
3988
3989         found = __find_space_info(info, flags);
3990         ASSERT(found);
3991         spin_lock(&found->lock);
3992         found->total_bytes += total_bytes;
3993         found->disk_total += total_bytes * factor;
3994         found->bytes_used += bytes_used;
3995         found->disk_used += bytes_used * factor;
3996         found->bytes_readonly += bytes_readonly;
3997         if (total_bytes > 0)
3998                 found->full = 0;
3999         space_info_add_new_bytes(info, found, total_bytes -
4000                                  bytes_used - bytes_readonly);
4001         spin_unlock(&found->lock);
4002         *space_info = found;
4003 }
4004
4005 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
4006 {
4007         u64 extra_flags = chunk_to_extended(flags) &
4008                                 BTRFS_EXTENDED_PROFILE_MASK;
4009
4010         write_seqlock(&fs_info->profiles_lock);
4011         if (flags & BTRFS_BLOCK_GROUP_DATA)
4012                 fs_info->avail_data_alloc_bits |= extra_flags;
4013         if (flags & BTRFS_BLOCK_GROUP_METADATA)
4014                 fs_info->avail_metadata_alloc_bits |= extra_flags;
4015         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4016                 fs_info->avail_system_alloc_bits |= extra_flags;
4017         write_sequnlock(&fs_info->profiles_lock);
4018 }
4019
4020 /*
4021  * returns target flags in extended format or 0 if restripe for this
4022  * chunk_type is not in progress
4023  *
4024  * should be called with balance_lock held
4025  */
4026 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4027 {
4028         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4029         u64 target = 0;
4030
4031         if (!bctl)
4032                 return 0;
4033
4034         if (flags & BTRFS_BLOCK_GROUP_DATA &&
4035             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4036                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4037         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4038                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4039                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4040         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4041                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4042                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4043         }
4044
4045         return target;
4046 }
4047
4048 /*
4049  * @flags: available profiles in extended format (see ctree.h)
4050  *
4051  * Returns reduced profile in chunk format.  If profile changing is in
4052  * progress (either running or paused) picks the target profile (if it's
4053  * already available), otherwise falls back to plain reducing.
4054  */
4055 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
4056 {
4057         u64 num_devices = fs_info->fs_devices->rw_devices;
4058         u64 target;
4059         u64 raid_type;
4060         u64 allowed = 0;
4061
4062         /*
4063          * see if restripe for this chunk_type is in progress, if so
4064          * try to reduce to the target profile
4065          */
4066         spin_lock(&fs_info->balance_lock);
4067         target = get_restripe_target(fs_info, flags);
4068         if (target) {
4069                 /* pick target profile only if it's already available */
4070                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4071                         spin_unlock(&fs_info->balance_lock);
4072                         return extended_to_chunk(target);
4073                 }
4074         }
4075         spin_unlock(&fs_info->balance_lock);
4076
4077         /* First, mask out the RAID levels which aren't possible */
4078         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4079                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4080                         allowed |= btrfs_raid_array[raid_type].bg_flag;
4081         }
4082         allowed &= flags;
4083
4084         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4085                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4086         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4087                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4088         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4089                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4090         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4091                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4092         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4093                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4094
4095         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4096
4097         return extended_to_chunk(flags | allowed);
4098 }
4099
4100 static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
4101 {
4102         unsigned seq;
4103         u64 flags;
4104
4105         do {
4106                 flags = orig_flags;
4107                 seq = read_seqbegin(&fs_info->profiles_lock);
4108
4109                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4110                         flags |= fs_info->avail_data_alloc_bits;
4111                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4112                         flags |= fs_info->avail_system_alloc_bits;
4113                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4114                         flags |= fs_info->avail_metadata_alloc_bits;
4115         } while (read_seqretry(&fs_info->profiles_lock, seq));
4116
4117         return btrfs_reduce_alloc_profile(fs_info, flags);
4118 }
4119
4120 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
4121 {
4122         struct btrfs_fs_info *fs_info = root->fs_info;
4123         u64 flags;
4124         u64 ret;
4125
4126         if (data)
4127                 flags = BTRFS_BLOCK_GROUP_DATA;
4128         else if (root == fs_info->chunk_root)
4129                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4130         else
4131                 flags = BTRFS_BLOCK_GROUP_METADATA;
4132
4133         ret = get_alloc_profile(fs_info, flags);
4134         return ret;
4135 }
4136
4137 u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
4138 {
4139         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
4140 }
4141
4142 u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
4143 {
4144         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4145 }
4146
4147 u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
4148 {
4149         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4150 }
4151
4152 static u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
4153                                  bool may_use_included)
4154 {
4155         ASSERT(s_info);
4156         return s_info->bytes_used + s_info->bytes_reserved +
4157                 s_info->bytes_pinned + s_info->bytes_readonly +
4158                 (may_use_included ? s_info->bytes_may_use : 0);
4159 }
4160
4161 int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes)
4162 {
4163         struct btrfs_root *root = inode->root;
4164         struct btrfs_fs_info *fs_info = root->fs_info;
4165         struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
4166         u64 used;
4167         int ret = 0;
4168         int need_commit = 2;
4169         int have_pinned_space;
4170
4171         /* make sure bytes are sectorsize aligned */
4172         bytes = ALIGN(bytes, fs_info->sectorsize);
4173
4174         if (btrfs_is_free_space_inode(inode)) {
4175                 need_commit = 0;
4176                 ASSERT(current->journal_info);
4177         }
4178
4179 again:
4180         /* make sure we have enough space to handle the data first */
4181         spin_lock(&data_sinfo->lock);
4182         used = btrfs_space_info_used(data_sinfo, true);
4183
4184         if (used + bytes > data_sinfo->total_bytes) {
4185                 struct btrfs_trans_handle *trans;
4186
4187                 /*
4188                  * if we don't have enough free bytes in this space then we need
4189                  * to alloc a new chunk.
4190                  */
4191                 if (!data_sinfo->full) {
4192                         u64 alloc_target;
4193
4194                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4195                         spin_unlock(&data_sinfo->lock);
4196
4197                         alloc_target = btrfs_data_alloc_profile(fs_info);
4198                         /*
4199                          * It is ugly that we don't call nolock join
4200                          * transaction for the free space inode case here.
4201                          * But it is safe because we only do the data space
4202                          * reservation for the free space cache in the
4203                          * transaction context, the common join transaction
4204                          * just increase the counter of the current transaction
4205                          * handler, doesn't try to acquire the trans_lock of
4206                          * the fs.
4207                          */
4208                         trans = btrfs_join_transaction(root);
4209                         if (IS_ERR(trans))
4210                                 return PTR_ERR(trans);
4211
4212                         ret = do_chunk_alloc(trans, alloc_target,
4213                                              CHUNK_ALLOC_NO_FORCE);
4214                         btrfs_end_transaction(trans);
4215                         if (ret < 0) {
4216                                 if (ret != -ENOSPC)
4217                                         return ret;
4218                                 else {
4219                                         have_pinned_space = 1;
4220                                         goto commit_trans;
4221                                 }
4222                         }
4223
4224                         goto again;
4225                 }
4226
4227                 /*
4228                  * If we don't have enough pinned space to deal with this
4229                  * allocation, and no removed chunk in current transaction,
4230                  * don't bother committing the transaction.
4231                  */
4232                 have_pinned_space = __percpu_counter_compare(
4233                         &data_sinfo->total_bytes_pinned,
4234                         used + bytes - data_sinfo->total_bytes,
4235                         BTRFS_TOTAL_BYTES_PINNED_BATCH);
4236                 spin_unlock(&data_sinfo->lock);
4237
4238                 /* commit the current transaction and try again */
4239 commit_trans:
4240                 if (need_commit) {
4241                         need_commit--;
4242
4243                         if (need_commit > 0) {
4244                                 btrfs_start_delalloc_roots(fs_info, -1);
4245                                 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0,
4246                                                          (u64)-1);
4247                         }
4248
4249                         trans = btrfs_join_transaction(root);
4250                         if (IS_ERR(trans))
4251                                 return PTR_ERR(trans);
4252                         if (have_pinned_space >= 0 ||
4253                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4254                                      &trans->transaction->flags) ||
4255                             need_commit > 0) {
4256                                 ret = btrfs_commit_transaction(trans);
4257                                 if (ret)
4258                                         return ret;
4259                                 /*
4260                                  * The cleaner kthread might still be doing iput
4261                                  * operations. Wait for it to finish so that
4262                                  * more space is released.
4263                                  */
4264                                 mutex_lock(&fs_info->cleaner_delayed_iput_mutex);
4265                                 mutex_unlock(&fs_info->cleaner_delayed_iput_mutex);
4266                                 goto again;
4267                         } else {
4268                                 btrfs_end_transaction(trans);
4269                         }
4270                 }
4271
4272                 trace_btrfs_space_reservation(fs_info,
4273                                               "space_info:enospc",
4274                                               data_sinfo->flags, bytes, 1);
4275                 return -ENOSPC;
4276         }
4277         update_bytes_may_use(data_sinfo, bytes);
4278         trace_btrfs_space_reservation(fs_info, "space_info",
4279                                       data_sinfo->flags, bytes, 1);
4280         spin_unlock(&data_sinfo->lock);
4281
4282         return 0;
4283 }
4284
4285 int btrfs_check_data_free_space(struct inode *inode,
4286                         struct extent_changeset **reserved, u64 start, u64 len)
4287 {
4288         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4289         int ret;
4290
4291         /* align the range */
4292         len = round_up(start + len, fs_info->sectorsize) -
4293               round_down(start, fs_info->sectorsize);
4294         start = round_down(start, fs_info->sectorsize);
4295
4296         ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), len);
4297         if (ret < 0)
4298                 return ret;
4299
4300         /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4301         ret = btrfs_qgroup_reserve_data(inode, reserved, start, len);
4302         if (ret < 0)
4303                 btrfs_free_reserved_data_space_noquota(inode, start, len);
4304         else
4305                 ret = 0;
4306         return ret;
4307 }
4308
4309 /*
4310  * Called if we need to clear a data reservation for this inode
4311  * Normally in a error case.
4312  *
4313  * This one will *NOT* use accurate qgroup reserved space API, just for case
4314  * which we can't sleep and is sure it won't affect qgroup reserved space.
4315  * Like clear_bit_hook().
4316  */
4317 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4318                                             u64 len)
4319 {
4320         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4321         struct btrfs_space_info *data_sinfo;
4322
4323         /* Make sure the range is aligned to sectorsize */
4324         len = round_up(start + len, fs_info->sectorsize) -
4325               round_down(start, fs_info->sectorsize);
4326         start = round_down(start, fs_info->sectorsize);
4327
4328         data_sinfo = fs_info->data_sinfo;
4329         spin_lock(&data_sinfo->lock);
4330         update_bytes_may_use(data_sinfo, -len);
4331         trace_btrfs_space_reservation(fs_info, "space_info",
4332                                       data_sinfo->flags, len, 0);
4333         spin_unlock(&data_sinfo->lock);
4334 }
4335
4336 /*
4337  * Called if we need to clear a data reservation for this inode
4338  * Normally in a error case.
4339  *
4340  * This one will handle the per-inode data rsv map for accurate reserved
4341  * space framework.
4342  */
4343 void btrfs_free_reserved_data_space(struct inode *inode,
4344                         struct extent_changeset *reserved, u64 start, u64 len)
4345 {
4346         struct btrfs_root *root = BTRFS_I(inode)->root;
4347
4348         /* Make sure the range is aligned to sectorsize */
4349         len = round_up(start + len, root->fs_info->sectorsize) -
4350               round_down(start, root->fs_info->sectorsize);
4351         start = round_down(start, root->fs_info->sectorsize);
4352
4353         btrfs_free_reserved_data_space_noquota(inode, start, len);
4354         btrfs_qgroup_free_data(inode, reserved, start, len);
4355 }
4356
4357 static void force_metadata_allocation(struct btrfs_fs_info *info)
4358 {
4359         struct list_head *head = &info->space_info;
4360         struct btrfs_space_info *found;
4361
4362         rcu_read_lock();
4363         list_for_each_entry_rcu(found, head, list) {
4364                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4365                         found->force_alloc = CHUNK_ALLOC_FORCE;
4366         }
4367         rcu_read_unlock();
4368 }
4369
4370 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4371 {
4372         return (global->size << 1);
4373 }
4374
4375 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
4376                               struct btrfs_space_info *sinfo, int force)
4377 {
4378         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4379         u64 bytes_used = btrfs_space_info_used(sinfo, false);
4380         u64 thresh;
4381
4382         if (force == CHUNK_ALLOC_FORCE)
4383                 return 1;
4384
4385         /*
4386          * We need to take into account the global rsv because for all intents
4387          * and purposes it's used space.  Don't worry about locking the
4388          * global_rsv, it doesn't change except when the transaction commits.
4389          */
4390         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4391                 bytes_used += calc_global_rsv_need_space(global_rsv);
4392
4393         /*
4394          * in limited mode, we want to have some free space up to
4395          * about 1% of the FS size.
4396          */
4397         if (force == CHUNK_ALLOC_LIMITED) {
4398                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
4399                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4400
4401                 if (sinfo->total_bytes - bytes_used < thresh)
4402                         return 1;
4403         }
4404
4405         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
4406                 return 0;
4407         return 1;
4408 }
4409
4410 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4411 {
4412         u64 num_dev;
4413
4414         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4415                     BTRFS_BLOCK_GROUP_RAID0 |
4416                     BTRFS_BLOCK_GROUP_RAID5 |
4417                     BTRFS_BLOCK_GROUP_RAID6))
4418                 num_dev = fs_info->fs_devices->rw_devices;
4419         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4420                 num_dev = 2;
4421         else
4422                 num_dev = 1;    /* DUP or single */
4423
4424         return num_dev;
4425 }
4426
4427 /*
4428  * If @is_allocation is true, reserve space in the system space info necessary
4429  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4430  * removing a chunk.
4431  */
4432 void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
4433 {
4434         struct btrfs_fs_info *fs_info = trans->fs_info;
4435         struct btrfs_space_info *info;
4436         u64 left;
4437         u64 thresh;
4438         int ret = 0;
4439         u64 num_devs;
4440
4441         /*
4442          * Needed because we can end up allocating a system chunk and for an
4443          * atomic and race free space reservation in the chunk block reserve.
4444          */
4445         lockdep_assert_held(&fs_info->chunk_mutex);
4446
4447         info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4448         spin_lock(&info->lock);
4449         left = info->total_bytes - btrfs_space_info_used(info, true);
4450         spin_unlock(&info->lock);
4451
4452         num_devs = get_profile_num_devs(fs_info, type);
4453
4454         /* num_devs device items to update and 1 chunk item to add or remove */
4455         thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
4456                 btrfs_calc_trans_metadata_size(fs_info, 1);
4457
4458         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4459                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4460                            left, thresh, type);
4461                 dump_space_info(fs_info, info, 0, 0);
4462         }
4463
4464         if (left < thresh) {
4465                 u64 flags = btrfs_system_alloc_profile(fs_info);
4466
4467                 /*
4468                  * Ignore failure to create system chunk. We might end up not
4469                  * needing it, as we might not need to COW all nodes/leafs from
4470                  * the paths we visit in the chunk tree (they were already COWed
4471                  * or created in the current transaction for example).
4472                  */
4473                 ret = btrfs_alloc_chunk(trans, flags);
4474         }
4475
4476         if (!ret) {
4477                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
4478                                           &fs_info->chunk_block_rsv,
4479                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4480                 if (!ret)
4481                         trans->chunk_bytes_reserved += thresh;
4482         }
4483 }
4484
4485 /*
4486  * If force is CHUNK_ALLOC_FORCE:
4487  *    - return 1 if it successfully allocates a chunk,
4488  *    - return errors including -ENOSPC otherwise.
4489  * If force is NOT CHUNK_ALLOC_FORCE:
4490  *    - return 0 if it doesn't need to allocate a new chunk,
4491  *    - return 1 if it successfully allocates a chunk,
4492  *    - return errors including -ENOSPC otherwise.
4493  */
4494 static int do_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
4495                           int force)
4496 {
4497         struct btrfs_fs_info *fs_info = trans->fs_info;
4498         struct btrfs_space_info *space_info;
4499         bool wait_for_alloc = false;
4500         bool should_alloc = false;
4501         int ret = 0;
4502
4503         /* Don't re-enter if we're already allocating a chunk */
4504         if (trans->allocating_chunk)
4505                 return -ENOSPC;
4506
4507         space_info = __find_space_info(fs_info, flags);
4508         ASSERT(space_info);
4509
4510         do {
4511                 spin_lock(&space_info->lock);
4512                 if (force < space_info->force_alloc)
4513                         force = space_info->force_alloc;
4514                 should_alloc = should_alloc_chunk(fs_info, space_info, force);
4515                 if (space_info->full) {
4516                         /* No more free physical space */
4517                         if (should_alloc)
4518                                 ret = -ENOSPC;
4519                         else
4520                                 ret = 0;
4521                         spin_unlock(&space_info->lock);
4522                         return ret;
4523                 } else if (!should_alloc) {
4524                         spin_unlock(&space_info->lock);
4525                         return 0;
4526                 } else if (space_info->chunk_alloc) {
4527                         /*
4528                          * Someone is already allocating, so we need to block
4529                          * until this someone is finished and then loop to
4530                          * recheck if we should continue with our allocation
4531                          * attempt.
4532                          */
4533                         wait_for_alloc = true;
4534                         spin_unlock(&space_info->lock);
4535                         mutex_lock(&fs_info->chunk_mutex);
4536                         mutex_unlock(&fs_info->chunk_mutex);
4537                 } else {
4538                         /* Proceed with allocation */
4539                         space_info->chunk_alloc = 1;
4540                         wait_for_alloc = false;
4541                         spin_unlock(&space_info->lock);
4542                 }
4543
4544                 cond_resched();
4545         } while (wait_for_alloc);
4546
4547         mutex_lock(&fs_info->chunk_mutex);
4548         trans->allocating_chunk = true;
4549
4550         /*
4551          * If we have mixed data/metadata chunks we want to make sure we keep
4552          * allocating mixed chunks instead of individual chunks.
4553          */
4554         if (btrfs_mixed_space_info(space_info))
4555                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4556
4557         /*
4558          * if we're doing a data chunk, go ahead and make sure that
4559          * we keep a reasonable number of metadata chunks allocated in the
4560          * FS as well.
4561          */
4562         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4563                 fs_info->data_chunk_allocations++;
4564                 if (!(fs_info->data_chunk_allocations %
4565                       fs_info->metadata_ratio))
4566                         force_metadata_allocation(fs_info);
4567         }
4568
4569         /*
4570          * Check if we have enough space in SYSTEM chunk because we may need
4571          * to update devices.
4572          */
4573         check_system_chunk(trans, flags);
4574
4575         ret = btrfs_alloc_chunk(trans, flags);
4576         trans->allocating_chunk = false;
4577
4578         spin_lock(&space_info->lock);
4579         if (ret < 0) {
4580                 if (ret == -ENOSPC)
4581                         space_info->full = 1;
4582                 else
4583                         goto out;
4584         } else {
4585                 ret = 1;
4586                 space_info->max_extent_size = 0;
4587         }
4588
4589         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4590 out:
4591         space_info->chunk_alloc = 0;
4592         spin_unlock(&space_info->lock);
4593         mutex_unlock(&fs_info->chunk_mutex);
4594         /*
4595          * When we allocate a new chunk we reserve space in the chunk block
4596          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4597          * add new nodes/leafs to it if we end up needing to do it when
4598          * inserting the chunk item and updating device items as part of the
4599          * second phase of chunk allocation, performed by
4600          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4601          * large number of new block groups to create in our transaction
4602          * handle's new_bgs list to avoid exhausting the chunk block reserve
4603          * in extreme cases - like having a single transaction create many new
4604          * block groups when starting to write out the free space caches of all
4605          * the block groups that were made dirty during the lifetime of the
4606          * transaction.
4607          */
4608         if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
4609                 btrfs_create_pending_block_groups(trans);
4610
4611         return ret;
4612 }
4613
4614 static int can_overcommit(struct btrfs_fs_info *fs_info,
4615                           struct btrfs_space_info *space_info, u64 bytes,
4616                           enum btrfs_reserve_flush_enum flush,
4617                           bool system_chunk)
4618 {
4619         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4620         u64 profile;
4621         u64 space_size;
4622         u64 avail;
4623         u64 used;
4624         int factor;
4625
4626         /* Don't overcommit when in mixed mode. */
4627         if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4628                 return 0;
4629
4630         if (system_chunk)
4631                 profile = btrfs_system_alloc_profile(fs_info);
4632         else
4633                 profile = btrfs_metadata_alloc_profile(fs_info);
4634
4635         used = btrfs_space_info_used(space_info, false);
4636
4637         /*
4638          * We only want to allow over committing if we have lots of actual space
4639          * free, but if we don't have enough space to handle the global reserve
4640          * space then we could end up having a real enospc problem when trying
4641          * to allocate a chunk or some other such important allocation.
4642          */
4643         spin_lock(&global_rsv->lock);
4644         space_size = calc_global_rsv_need_space(global_rsv);
4645         spin_unlock(&global_rsv->lock);
4646         if (used + space_size >= space_info->total_bytes)
4647                 return 0;
4648
4649         used += space_info->bytes_may_use;
4650
4651         avail = atomic64_read(&fs_info->free_chunk_space);
4652
4653         /*
4654          * If we have dup, raid1 or raid10 then only half of the free
4655          * space is actually useable.  For raid56, the space info used
4656          * doesn't include the parity drive, so we don't have to
4657          * change the math
4658          */
4659         factor = btrfs_bg_type_to_factor(profile);
4660         avail = div_u64(avail, factor);
4661
4662         /*
4663          * If we aren't flushing all things, let us overcommit up to
4664          * 1/2th of the space. If we can flush, don't let us overcommit
4665          * too much, let it overcommit up to 1/8 of the space.
4666          */
4667         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4668                 avail >>= 3;
4669         else
4670                 avail >>= 1;
4671
4672         if (used + bytes < space_info->total_bytes + avail)
4673                 return 1;
4674         return 0;
4675 }
4676
4677 static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
4678                                          unsigned long nr_pages, int nr_items)
4679 {
4680         struct super_block *sb = fs_info->sb;
4681
4682         if (down_read_trylock(&sb->s_umount)) {
4683                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4684                 up_read(&sb->s_umount);
4685         } else {
4686                 /*
4687                  * We needn't worry the filesystem going from r/w to r/o though
4688                  * we don't acquire ->s_umount mutex, because the filesystem
4689                  * should guarantee the delalloc inodes list be empty after
4690                  * the filesystem is readonly(all dirty pages are written to
4691                  * the disk).
4692                  */
4693                 btrfs_start_delalloc_roots(fs_info, nr_items);
4694                 if (!current->journal_info)
4695                         btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
4696         }
4697 }
4698
4699 static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
4700                                         u64 to_reclaim)
4701 {
4702         u64 bytes;
4703         u64 nr;
4704
4705         bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
4706         nr = div64_u64(to_reclaim, bytes);
4707         if (!nr)
4708                 nr = 1;
4709         return nr;
4710 }
4711
4712 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4713
4714 /*
4715  * shrink metadata reservation for delalloc
4716  */
4717 static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
4718                             u64 orig, bool wait_ordered)
4719 {
4720         struct btrfs_space_info *space_info;
4721         struct btrfs_trans_handle *trans;
4722         u64 delalloc_bytes;
4723         u64 max_reclaim;
4724         u64 items;
4725         long time_left;
4726         unsigned long nr_pages;
4727         int loops;
4728
4729         /* Calc the number of the pages we need flush for space reservation */
4730         items = calc_reclaim_items_nr(fs_info, to_reclaim);
4731         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4732
4733         trans = (struct btrfs_trans_handle *)current->journal_info;
4734         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4735
4736         delalloc_bytes = percpu_counter_sum_positive(
4737                                                 &fs_info->delalloc_bytes);
4738         if (delalloc_bytes == 0) {
4739                 if (trans)
4740                         return;
4741                 if (wait_ordered)
4742                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4743                 return;
4744         }
4745
4746         loops = 0;
4747         while (delalloc_bytes && loops < 3) {
4748                 max_reclaim = min(delalloc_bytes, to_reclaim);
4749                 nr_pages = max_reclaim >> PAGE_SHIFT;
4750                 btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items);
4751                 /*
4752                  * We need to wait for the async pages to actually start before
4753                  * we do anything.
4754                  */
4755                 max_reclaim = atomic_read(&fs_info->async_delalloc_pages);
4756                 if (!max_reclaim)
4757                         goto skip_async;
4758
4759                 if (max_reclaim <= nr_pages)
4760                         max_reclaim = 0;
4761                 else
4762                         max_reclaim -= nr_pages;
4763
4764                 wait_event(fs_info->async_submit_wait,
4765                            atomic_read(&fs_info->async_delalloc_pages) <=
4766                            (int)max_reclaim);
4767 skip_async:
4768                 spin_lock(&space_info->lock);
4769                 if (list_empty(&space_info->tickets) &&
4770                     list_empty(&space_info->priority_tickets)) {
4771                         spin_unlock(&space_info->lock);
4772                         break;
4773                 }
4774                 spin_unlock(&space_info->lock);
4775
4776                 loops++;
4777                 if (wait_ordered && !trans) {
4778                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4779                 } else {
4780                         time_left = schedule_timeout_killable(1);
4781                         if (time_left)
4782                                 break;
4783                 }
4784                 delalloc_bytes = percpu_counter_sum_positive(
4785                                                 &fs_info->delalloc_bytes);
4786         }
4787 }
4788
4789 struct reserve_ticket {
4790         u64 bytes;
4791         int error;
4792         struct list_head list;
4793         wait_queue_head_t wait;
4794 };
4795
4796 /**
4797  * maybe_commit_transaction - possibly commit the transaction if its ok to
4798  * @root - the root we're allocating for
4799  * @bytes - the number of bytes we want to reserve
4800  * @force - force the commit
4801  *
4802  * This will check to make sure that committing the transaction will actually
4803  * get us somewhere and then commit the transaction if it does.  Otherwise it
4804  * will return -ENOSPC.
4805  */
4806 static int may_commit_transaction(struct btrfs_fs_info *fs_info,
4807                                   struct btrfs_space_info *space_info)
4808 {
4809         struct reserve_ticket *ticket = NULL;
4810         struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
4811         struct btrfs_trans_handle *trans;
4812         u64 bytes;
4813
4814         trans = (struct btrfs_trans_handle *)current->journal_info;
4815         if (trans)
4816                 return -EAGAIN;
4817
4818         spin_lock(&space_info->lock);
4819         if (!list_empty(&space_info->priority_tickets))
4820                 ticket = list_first_entry(&space_info->priority_tickets,
4821                                           struct reserve_ticket, list);
4822         else if (!list_empty(&space_info->tickets))
4823                 ticket = list_first_entry(&space_info->tickets,
4824                                           struct reserve_ticket, list);
4825         bytes = (ticket) ? ticket->bytes : 0;
4826         spin_unlock(&space_info->lock);
4827
4828         if (!bytes)
4829                 return 0;
4830
4831         /* See if there is enough pinned space to make this reservation */
4832         if (__percpu_counter_compare(&space_info->total_bytes_pinned,
4833                                    bytes,
4834                                    BTRFS_TOTAL_BYTES_PINNED_BATCH) >= 0)
4835                 goto commit;
4836
4837         /*
4838          * See if there is some space in the delayed insertion reservation for
4839          * this reservation.
4840          */
4841         if (space_info != delayed_rsv->space_info)
4842                 return -ENOSPC;
4843
4844         spin_lock(&delayed_rsv->lock);
4845         if (delayed_rsv->size > bytes)
4846                 bytes = 0;
4847         else
4848                 bytes -= delayed_rsv->size;
4849         spin_unlock(&delayed_rsv->lock);
4850
4851         if (__percpu_counter_compare(&space_info->total_bytes_pinned,
4852                                    bytes,
4853                                    BTRFS_TOTAL_BYTES_PINNED_BATCH) < 0) {
4854                 return -ENOSPC;
4855         }
4856
4857 commit:
4858         trans = btrfs_join_transaction(fs_info->extent_root);
4859         if (IS_ERR(trans))
4860                 return -ENOSPC;
4861
4862         return btrfs_commit_transaction(trans);
4863 }
4864
4865 /*
4866  * Try to flush some data based on policy set by @state. This is only advisory
4867  * and may fail for various reasons. The caller is supposed to examine the
4868  * state of @space_info to detect the outcome.
4869  */
4870 static void flush_space(struct btrfs_fs_info *fs_info,
4871                        struct btrfs_space_info *space_info, u64 num_bytes,
4872                        int state)
4873 {
4874         struct btrfs_root *root = fs_info->extent_root;
4875         struct btrfs_trans_handle *trans;
4876         int nr;
4877         int ret = 0;
4878
4879         switch (state) {
4880         case FLUSH_DELAYED_ITEMS_NR:
4881         case FLUSH_DELAYED_ITEMS:
4882                 if (state == FLUSH_DELAYED_ITEMS_NR)
4883                         nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
4884                 else
4885                         nr = -1;
4886
4887                 trans = btrfs_join_transaction(root);
4888                 if (IS_ERR(trans)) {
4889                         ret = PTR_ERR(trans);
4890                         break;
4891                 }
4892                 ret = btrfs_run_delayed_items_nr(trans, nr);
4893                 btrfs_end_transaction(trans);
4894                 break;
4895         case FLUSH_DELALLOC:
4896         case FLUSH_DELALLOC_WAIT:
4897                 shrink_delalloc(fs_info, num_bytes * 2, num_bytes,
4898                                 state == FLUSH_DELALLOC_WAIT);
4899                 break;
4900         case ALLOC_CHUNK:
4901                 trans = btrfs_join_transaction(root);
4902                 if (IS_ERR(trans)) {
4903                         ret = PTR_ERR(trans);
4904                         break;
4905                 }
4906                 ret = do_chunk_alloc(trans,
4907                                      btrfs_metadata_alloc_profile(fs_info),
4908                                      CHUNK_ALLOC_NO_FORCE);
4909                 btrfs_end_transaction(trans);
4910                 if (ret > 0 || ret == -ENOSPC)
4911                         ret = 0;
4912                 break;
4913         case COMMIT_TRANS:
4914                 ret = may_commit_transaction(fs_info, space_info);
4915                 break;
4916         default:
4917                 ret = -ENOSPC;
4918                 break;
4919         }
4920
4921         trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
4922                                 ret);
4923         return;
4924 }
4925
4926 static inline u64
4927 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
4928                                  struct btrfs_space_info *space_info,
4929                                  bool system_chunk)
4930 {
4931         struct reserve_ticket *ticket;
4932         u64 used;
4933         u64 expected;
4934         u64 to_reclaim = 0;
4935
4936         list_for_each_entry(ticket, &space_info->tickets, list)
4937                 to_reclaim += ticket->bytes;
4938         list_for_each_entry(ticket, &space_info->priority_tickets, list)
4939                 to_reclaim += ticket->bytes;
4940         if (to_reclaim)
4941                 return to_reclaim;
4942
4943         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4944         if (can_overcommit(fs_info, space_info, to_reclaim,
4945                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
4946                 return 0;
4947
4948         used = btrfs_space_info_used(space_info, true);
4949
4950         if (can_overcommit(fs_info, space_info, SZ_1M,
4951                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
4952                 expected = div_factor_fine(space_info->total_bytes, 95);
4953         else
4954                 expected = div_factor_fine(space_info->total_bytes, 90);
4955
4956         if (used > expected)
4957                 to_reclaim = used - expected;
4958         else
4959                 to_reclaim = 0;
4960         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4961                                      space_info->bytes_reserved);
4962         return to_reclaim;
4963 }
4964
4965 static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
4966                                         struct btrfs_space_info *space_info,
4967                                         u64 used, bool system_chunk)
4968 {
4969         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4970
4971         /* If we're just plain full then async reclaim just slows us down. */
4972         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4973                 return 0;
4974
4975         if (!btrfs_calc_reclaim_metadata_size(fs_info, space_info,
4976                                               system_chunk))
4977                 return 0;
4978
4979         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4980                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4981 }
4982
4983 static void wake_all_tickets(struct list_head *head)
4984 {
4985         struct reserve_ticket *ticket;
4986
4987         while (!list_empty(head)) {
4988                 ticket = list_first_entry(head, struct reserve_ticket, list);
4989                 list_del_init(&ticket->list);
4990                 ticket->error = -ENOSPC;
4991                 wake_up(&ticket->wait);
4992         }
4993 }
4994
4995 /*
4996  * This is for normal flushers, we can wait all goddamned day if we want to.  We
4997  * will loop and continuously try to flush as long as we are making progress.
4998  * We count progress as clearing off tickets each time we have to loop.
4999  */
5000 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
5001 {
5002         struct btrfs_fs_info *fs_info;
5003         struct btrfs_space_info *space_info;
5004         u64 to_reclaim;
5005         int flush_state;
5006         int commit_cycles = 0;
5007         u64 last_tickets_id;
5008
5009         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
5010         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5011
5012         spin_lock(&space_info->lock);
5013         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5014                                                       false);
5015         if (!to_reclaim) {
5016                 space_info->flush = 0;
5017                 spin_unlock(&space_info->lock);
5018                 return;
5019         }
5020         last_tickets_id = space_info->tickets_id;
5021         spin_unlock(&space_info->lock);
5022
5023         flush_state = FLUSH_DELAYED_ITEMS_NR;
5024         do {
5025                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5026                 spin_lock(&space_info->lock);
5027                 if (list_empty(&space_info->tickets)) {
5028                         space_info->flush = 0;
5029                         spin_unlock(&space_info->lock);
5030                         return;
5031                 }
5032                 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
5033                                                               space_info,
5034                                                               false);
5035                 if (last_tickets_id == space_info->tickets_id) {
5036                         flush_state++;
5037                 } else {
5038                         last_tickets_id = space_info->tickets_id;
5039                         flush_state = FLUSH_DELAYED_ITEMS_NR;
5040                         if (commit_cycles)
5041                                 commit_cycles--;
5042                 }
5043
5044                 if (flush_state > COMMIT_TRANS) {
5045                         commit_cycles++;
5046                         if (commit_cycles > 2) {
5047                                 wake_all_tickets(&space_info->tickets);
5048                                 space_info->flush = 0;
5049                         } else {
5050                                 flush_state = FLUSH_DELAYED_ITEMS_NR;
5051                         }
5052                 }
5053                 spin_unlock(&space_info->lock);
5054         } while (flush_state <= COMMIT_TRANS);
5055 }
5056
5057 void btrfs_init_async_reclaim_work(struct work_struct *work)
5058 {
5059         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5060 }
5061
5062 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5063                                             struct btrfs_space_info *space_info,
5064                                             struct reserve_ticket *ticket)
5065 {
5066         u64 to_reclaim;
5067         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5068
5069         spin_lock(&space_info->lock);
5070         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5071                                                       false);
5072         if (!to_reclaim) {
5073                 spin_unlock(&space_info->lock);
5074                 return;
5075         }
5076         spin_unlock(&space_info->lock);
5077
5078         do {
5079                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5080                 flush_state++;
5081                 spin_lock(&space_info->lock);
5082                 if (ticket->bytes == 0) {
5083                         spin_unlock(&space_info->lock);
5084                         return;
5085                 }
5086                 spin_unlock(&space_info->lock);
5087
5088                 /*
5089                  * Priority flushers can't wait on delalloc without
5090                  * deadlocking.
5091                  */
5092                 if (flush_state == FLUSH_DELALLOC ||
5093                     flush_state == FLUSH_DELALLOC_WAIT)
5094                         flush_state = ALLOC_CHUNK;
5095         } while (flush_state < COMMIT_TRANS);
5096 }
5097
5098 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5099                                struct btrfs_space_info *space_info,
5100                                struct reserve_ticket *ticket, u64 orig_bytes)
5101
5102 {
5103         DEFINE_WAIT(wait);
5104         int ret = 0;
5105
5106         spin_lock(&space_info->lock);
5107         while (ticket->bytes > 0 && ticket->error == 0) {
5108                 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5109                 if (ret) {
5110                         ret = -EINTR;
5111                         break;
5112                 }
5113                 spin_unlock(&space_info->lock);
5114
5115                 schedule();
5116
5117                 finish_wait(&ticket->wait, &wait);
5118                 spin_lock(&space_info->lock);
5119         }
5120         if (!ret)
5121                 ret = ticket->error;
5122         if (!list_empty(&ticket->list))
5123                 list_del_init(&ticket->list);
5124         if (ticket->bytes && ticket->bytes < orig_bytes) {
5125                 u64 num_bytes = orig_bytes - ticket->bytes;
5126                 update_bytes_may_use(space_info, -num_bytes);
5127                 trace_btrfs_space_reservation(fs_info, "space_info",
5128                                               space_info->flags, num_bytes, 0);
5129         }
5130         spin_unlock(&space_info->lock);
5131
5132         return ret;
5133 }
5134
5135 /**
5136  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5137  * @root - the root we're allocating for
5138  * @space_info - the space info we want to allocate from
5139  * @orig_bytes - the number of bytes we want
5140  * @flush - whether or not we can flush to make our reservation
5141  *
5142  * This will reserve orig_bytes number of bytes from the space info associated
5143  * with the block_rsv.  If there is not enough space it will make an attempt to
5144  * flush out space to make room.  It will do this by flushing delalloc if
5145  * possible or committing the transaction.  If flush is 0 then no attempts to
5146  * regain reservations will be made and this will fail if there is not enough
5147  * space already.
5148  */
5149 static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
5150                                     struct btrfs_space_info *space_info,
5151                                     u64 orig_bytes,
5152                                     enum btrfs_reserve_flush_enum flush,
5153                                     bool system_chunk)
5154 {
5155         struct reserve_ticket ticket;
5156         u64 used;
5157         int ret = 0;
5158
5159         ASSERT(orig_bytes);
5160         ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5161
5162         spin_lock(&space_info->lock);
5163         ret = -ENOSPC;
5164         used = btrfs_space_info_used(space_info, true);
5165
5166         /*
5167          * If we have enough space then hooray, make our reservation and carry
5168          * on.  If not see if we can overcommit, and if we can, hooray carry on.
5169          * If not things get more complicated.
5170          */
5171         if (used + orig_bytes <= space_info->total_bytes) {
5172                 update_bytes_may_use(space_info, orig_bytes);
5173                 trace_btrfs_space_reservation(fs_info, "space_info",
5174                                               space_info->flags, orig_bytes, 1);
5175                 ret = 0;
5176         } else if (can_overcommit(fs_info, space_info, orig_bytes, flush,
5177                                   system_chunk)) {
5178                 update_bytes_may_use(space_info, orig_bytes);
5179                 trace_btrfs_space_reservation(fs_info, "space_info",
5180                                               space_info->flags, orig_bytes, 1);
5181                 ret = 0;
5182         }
5183
5184         /*
5185          * If we couldn't make a reservation then setup our reservation ticket
5186          * and kick the async worker if it's not already running.
5187          *
5188          * If we are a priority flusher then we just need to add our ticket to
5189          * the list and we will do our own flushing further down.
5190          */
5191         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5192                 ticket.bytes = orig_bytes;
5193                 ticket.error = 0;
5194                 init_waitqueue_head(&ticket.wait);
5195                 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5196                         list_add_tail(&ticket.list, &space_info->tickets);
5197                         if (!space_info->flush) {
5198                                 space_info->flush = 1;
5199                                 trace_btrfs_trigger_flush(fs_info,
5200                                                           space_info->flags,
5201                                                           orig_bytes, flush,
5202                                                           "enospc");
5203                                 queue_work(system_unbound_wq,
5204                                            &fs_info->async_reclaim_work);
5205                         }
5206                 } else {
5207                         list_add_tail(&ticket.list,
5208                                       &space_info->priority_tickets);
5209                 }
5210         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5211                 used += orig_bytes;
5212                 /*
5213                  * We will do the space reservation dance during log replay,
5214                  * which means we won't have fs_info->fs_root set, so don't do
5215                  * the async reclaim as we will panic.
5216                  */
5217                 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
5218                     need_do_async_reclaim(fs_info, space_info,
5219                                           used, system_chunk) &&
5220                     !work_busy(&fs_info->async_reclaim_work)) {
5221                         trace_btrfs_trigger_flush(fs_info, space_info->flags,
5222                                                   orig_bytes, flush, "preempt");
5223                         queue_work(system_unbound_wq,
5224                                    &fs_info->async_reclaim_work);
5225                 }
5226         }
5227         spin_unlock(&space_info->lock);
5228         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5229                 return ret;
5230
5231         if (flush == BTRFS_RESERVE_FLUSH_ALL)
5232                 return wait_reserve_ticket(fs_info, space_info, &ticket,
5233                                            orig_bytes);
5234
5235         ret = 0;
5236         priority_reclaim_metadata_space(fs_info, space_info, &ticket);
5237         spin_lock(&space_info->lock);
5238         if (ticket.bytes) {
5239                 if (ticket.bytes < orig_bytes) {
5240                         u64 num_bytes = orig_bytes - ticket.bytes;
5241                         update_bytes_may_use(space_info, -num_bytes);
5242                         trace_btrfs_space_reservation(fs_info, "space_info",
5243                                                       space_info->flags,
5244                                                       num_bytes, 0);
5245
5246                 }
5247                 list_del_init(&ticket.list);
5248                 ret = -ENOSPC;
5249         }
5250         spin_unlock(&space_info->lock);
5251         ASSERT(list_empty(&ticket.list));
5252         return ret;
5253 }
5254
5255 /**
5256  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5257  * @root - the root we're allocating for
5258  * @block_rsv - the block_rsv we're allocating for
5259  * @orig_bytes - the number of bytes we want
5260  * @flush - whether or not we can flush to make our reservation
5261  *
5262  * This will reserve orgi_bytes number of bytes from the space info associated
5263  * with the block_rsv.  If there is not enough space it will make an attempt to
5264  * flush out space to make room.  It will do this by flushing delalloc if
5265  * possible or committing the transaction.  If flush is 0 then no attempts to
5266  * regain reservations will be made and this will fail if there is not enough
5267  * space already.
5268  */
5269 static int reserve_metadata_bytes(struct btrfs_root *root,
5270                                   struct btrfs_block_rsv *block_rsv,
5271                                   u64 orig_bytes,
5272                                   enum btrfs_reserve_flush_enum flush)
5273 {
5274         struct btrfs_fs_info *fs_info = root->fs_info;
5275         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5276         int ret;
5277         bool system_chunk = (root == fs_info->chunk_root);
5278
5279         ret = __reserve_metadata_bytes(fs_info, block_rsv->space_info,
5280                                        orig_bytes, flush, system_chunk);
5281         if (ret == -ENOSPC &&
5282             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5283                 if (block_rsv != global_rsv &&
5284                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5285                         ret = 0;
5286         }
5287         if (ret == -ENOSPC) {
5288                 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
5289                                               block_rsv->space_info->flags,
5290                                               orig_bytes, 1);
5291
5292                 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
5293                         dump_space_info(fs_info, block_rsv->space_info,
5294                                         orig_bytes, 0);
5295         }
5296         return ret;
5297 }
5298
5299 static struct btrfs_block_rsv *get_block_rsv(
5300                                         const struct btrfs_trans_handle *trans,
5301                                         const struct btrfs_root *root)
5302 {
5303         struct btrfs_fs_info *fs_info = root->fs_info;
5304         struct btrfs_block_rsv *block_rsv = NULL;
5305
5306         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5307             (root == fs_info->csum_root && trans->adding_csums) ||
5308             (root == fs_info->uuid_root))
5309                 block_rsv = trans->block_rsv;
5310
5311         if (!block_rsv)
5312                 block_rsv = root->block_rsv;
5313
5314         if (!block_rsv)
5315                 block_rsv = &fs_info->empty_block_rsv;
5316
5317         return block_rsv;
5318 }
5319
5320 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5321                                u64 num_bytes)
5322 {
5323         int ret = -ENOSPC;
5324         spin_lock(&block_rsv->lock);
5325         if (block_rsv->reserved >= num_bytes) {
5326                 block_rsv->reserved -= num_bytes;
5327                 if (block_rsv->reserved < block_rsv->size)
5328                         block_rsv->full = 0;
5329                 ret = 0;
5330         }
5331         spin_unlock(&block_rsv->lock);
5332         return ret;
5333 }
5334
5335 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5336                                 u64 num_bytes, bool update_size)
5337 {
5338         spin_lock(&block_rsv->lock);
5339         block_rsv->reserved += num_bytes;
5340         if (update_size)
5341                 block_rsv->size += num_bytes;
5342         else if (block_rsv->reserved >= block_rsv->size)
5343                 block_rsv->full = 1;
5344         spin_unlock(&block_rsv->lock);
5345 }
5346
5347 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5348                              struct btrfs_block_rsv *dest, u64 num_bytes,
5349                              int min_factor)
5350 {
5351         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5352         u64 min_bytes;
5353
5354         if (global_rsv->space_info != dest->space_info)
5355                 return -ENOSPC;
5356
5357         spin_lock(&global_rsv->lock);
5358         min_bytes = div_factor(global_rsv->size, min_factor);
5359         if (global_rsv->reserved < min_bytes + num_bytes) {
5360                 spin_unlock(&global_rsv->lock);
5361                 return -ENOSPC;
5362         }
5363         global_rsv->reserved -= num_bytes;
5364         if (global_rsv->reserved < global_rsv->size)
5365                 global_rsv->full = 0;
5366         spin_unlock(&global_rsv->lock);
5367
5368         block_rsv_add_bytes(dest, num_bytes, true);
5369         return 0;
5370 }
5371
5372 /*
5373  * This is for space we already have accounted in space_info->bytes_may_use, so
5374  * basically when we're returning space from block_rsv's.
5375  */
5376 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5377                                      struct btrfs_space_info *space_info,
5378                                      u64 num_bytes)
5379 {
5380         struct reserve_ticket *ticket;
5381         struct list_head *head;
5382         u64 used;
5383         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5384         bool check_overcommit = false;
5385
5386         spin_lock(&space_info->lock);
5387         head = &space_info->priority_tickets;
5388
5389         /*
5390          * If we are over our limit then we need to check and see if we can
5391          * overcommit, and if we can't then we just need to free up our space
5392          * and not satisfy any requests.
5393          */
5394         used = btrfs_space_info_used(space_info, true);
5395         if (used - num_bytes >= space_info->total_bytes)
5396                 check_overcommit = true;
5397 again:
5398         while (!list_empty(head) && num_bytes) {
5399                 ticket = list_first_entry(head, struct reserve_ticket,
5400                                           list);
5401                 /*
5402                  * We use 0 bytes because this space is already reserved, so
5403                  * adding the ticket space would be a double count.
5404                  */
5405                 if (check_overcommit &&
5406                     !can_overcommit(fs_info, space_info, 0, flush, false))
5407                         break;
5408                 if (num_bytes >= ticket->bytes) {
5409                         list_del_init(&ticket->list);
5410                         num_bytes -= ticket->bytes;
5411                         ticket->bytes = 0;
5412                         space_info->tickets_id++;
5413                         wake_up(&ticket->wait);
5414                 } else {
5415                         ticket->bytes -= num_bytes;
5416                         num_bytes = 0;
5417                 }
5418         }
5419
5420         if (num_bytes && head == &space_info->priority_tickets) {
5421                 head = &space_info->tickets;
5422                 flush = BTRFS_RESERVE_FLUSH_ALL;
5423                 goto again;
5424         }
5425         update_bytes_may_use(space_info, -num_bytes);
5426         trace_btrfs_space_reservation(fs_info, "space_info",
5427                                       space_info->flags, num_bytes, 0);
5428         spin_unlock(&space_info->lock);
5429 }
5430
5431 /*
5432  * This is for newly allocated space that isn't accounted in
5433  * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
5434  * we use this helper.
5435  */
5436 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5437                                      struct btrfs_space_info *space_info,
5438                                      u64 num_bytes)
5439 {
5440         struct reserve_ticket *ticket;
5441         struct list_head *head = &space_info->priority_tickets;
5442
5443 again:
5444         while (!list_empty(head) && num_bytes) {
5445                 ticket = list_first_entry(head, struct reserve_ticket,
5446                                           list);
5447                 if (num_bytes >= ticket->bytes) {
5448                         trace_btrfs_space_reservation(fs_info, "space_info",
5449                                                       space_info->flags,
5450                                                       ticket->bytes, 1);
5451                         list_del_init(&ticket->list);
5452                         num_bytes -= ticket->bytes;
5453                         update_bytes_may_use(space_info, ticket->bytes);
5454                         ticket->bytes = 0;
5455                         space_info->tickets_id++;
5456                         wake_up(&ticket->wait);
5457                 } else {
5458                         trace_btrfs_space_reservation(fs_info, "space_info",
5459                                                       space_info->flags,
5460                                                       num_bytes, 1);
5461                         update_bytes_may_use(space_info, num_bytes);
5462                         ticket->bytes -= num_bytes;
5463                         num_bytes = 0;
5464                 }
5465         }
5466
5467         if (num_bytes && head == &space_info->priority_tickets) {
5468                 head = &space_info->tickets;
5469                 goto again;
5470         }
5471 }
5472
5473 static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5474                                     struct btrfs_block_rsv *block_rsv,
5475                                     struct btrfs_block_rsv *dest, u64 num_bytes,
5476                                     u64 *qgroup_to_release_ret)
5477 {
5478         struct btrfs_space_info *space_info = block_rsv->space_info;
5479         u64 qgroup_to_release = 0;
5480         u64 ret;
5481
5482         spin_lock(&block_rsv->lock);
5483         if (num_bytes == (u64)-1) {
5484                 num_bytes = block_rsv->size;
5485                 qgroup_to_release = block_rsv->qgroup_rsv_size;
5486         }
5487         block_rsv->size -= num_bytes;
5488         if (block_rsv->reserved >= block_rsv->size) {
5489                 num_bytes = block_rsv->reserved - block_rsv->size;
5490                 block_rsv->reserved = block_rsv->size;
5491                 block_rsv->full = 1;
5492         } else {
5493                 num_bytes = 0;
5494         }
5495         if (block_rsv->qgroup_rsv_reserved >= block_rsv->qgroup_rsv_size) {
5496                 qgroup_to_release = block_rsv->qgroup_rsv_reserved -
5497                                     block_rsv->qgroup_rsv_size;
5498                 block_rsv->qgroup_rsv_reserved = block_rsv->qgroup_rsv_size;
5499         } else {
5500                 qgroup_to_release = 0;
5501         }
5502         spin_unlock(&block_rsv->lock);
5503
5504         ret = num_bytes;
5505         if (num_bytes > 0) {
5506                 if (dest) {
5507                         spin_lock(&dest->lock);
5508                         if (!dest->full) {
5509                                 u64 bytes_to_add;
5510
5511                                 bytes_to_add = dest->size - dest->reserved;
5512                                 bytes_to_add = min(num_bytes, bytes_to_add);
5513                                 dest->reserved += bytes_to_add;
5514                                 if (dest->reserved >= dest->size)
5515                                         dest->full = 1;
5516                                 num_bytes -= bytes_to_add;
5517                         }
5518                         spin_unlock(&dest->lock);
5519                 }
5520                 if (num_bytes)
5521                         space_info_add_old_bytes(fs_info, space_info,
5522                                                  num_bytes);
5523         }
5524         if (qgroup_to_release_ret)
5525                 *qgroup_to_release_ret = qgroup_to_release;
5526         return ret;
5527 }
5528
5529 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5530                             struct btrfs_block_rsv *dst, u64 num_bytes,
5531                             bool update_size)
5532 {
5533         int ret;
5534
5535         ret = block_rsv_use_bytes(src, num_bytes);
5536         if (ret)
5537                 return ret;
5538
5539         block_rsv_add_bytes(dst, num_bytes, update_size);
5540         return 0;
5541 }
5542
5543 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5544 {
5545         memset(rsv, 0, sizeof(*rsv));
5546         spin_lock_init(&rsv->lock);
5547         rsv->type = type;
5548 }
5549
5550 void btrfs_init_metadata_block_rsv(struct btrfs_fs_info *fs_info,
5551                                    struct btrfs_block_rsv *rsv,
5552                                    unsigned short type)
5553 {
5554         btrfs_init_block_rsv(rsv, type);
5555         rsv->space_info = __find_space_info(fs_info,
5556                                             BTRFS_BLOCK_GROUP_METADATA);
5557 }
5558
5559 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
5560                                               unsigned short type)
5561 {
5562         struct btrfs_block_rsv *block_rsv;
5563
5564         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5565         if (!block_rsv)
5566                 return NULL;
5567
5568         btrfs_init_metadata_block_rsv(fs_info, block_rsv, type);
5569         return block_rsv;
5570 }
5571
5572 void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
5573                           struct btrfs_block_rsv *rsv)
5574 {
5575         if (!rsv)
5576                 return;
5577         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5578         kfree(rsv);
5579 }
5580
5581 int btrfs_block_rsv_add(struct btrfs_root *root,
5582                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5583                         enum btrfs_reserve_flush_enum flush)
5584 {
5585         int ret;
5586
5587         if (num_bytes == 0)
5588                 return 0;
5589
5590         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5591         if (!ret)
5592                 block_rsv_add_bytes(block_rsv, num_bytes, true);
5593
5594         return ret;
5595 }
5596
5597 int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
5598 {
5599         u64 num_bytes = 0;
5600         int ret = -ENOSPC;
5601
5602         if (!block_rsv)
5603                 return 0;
5604
5605         spin_lock(&block_rsv->lock);
5606         num_bytes = div_factor(block_rsv->size, min_factor);
5607         if (block_rsv->reserved >= num_bytes)
5608                 ret = 0;
5609         spin_unlock(&block_rsv->lock);
5610
5611         return ret;
5612 }
5613
5614 int btrfs_block_rsv_refill(struct btrfs_root *root,
5615                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5616                            enum btrfs_reserve_flush_enum flush)
5617 {
5618         u64 num_bytes = 0;
5619         int ret = -ENOSPC;
5620
5621         if (!block_rsv)
5622                 return 0;
5623
5624         spin_lock(&block_rsv->lock);
5625         num_bytes = min_reserved;
5626         if (block_rsv->reserved >= num_bytes)
5627                 ret = 0;
5628         else
5629                 num_bytes -= block_rsv->reserved;
5630         spin_unlock(&block_rsv->lock);
5631
5632         if (!ret)
5633                 return 0;
5634
5635         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5636         if (!ret) {
5637                 block_rsv_add_bytes(block_rsv, num_bytes, false);
5638                 return 0;
5639         }
5640
5641         return ret;
5642 }
5643
5644 /**
5645  * btrfs_inode_rsv_refill - refill the inode block rsv.
5646  * @inode - the inode we are refilling.
5647  * @flush - the flusing restriction.
5648  *
5649  * Essentially the same as btrfs_block_rsv_refill, except it uses the
5650  * block_rsv->size as the minimum size.  We'll either refill the missing amount
5651  * or return if we already have enough space.  This will also handle the resreve
5652  * tracepoint for the reserved amount.
5653  */
5654 static int btrfs_inode_rsv_refill(struct btrfs_inode *inode,
5655                                   enum btrfs_reserve_flush_enum flush)
5656 {
5657         struct btrfs_root *root = inode->root;
5658         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5659         u64 num_bytes = 0;
5660         u64 qgroup_num_bytes = 0;
5661         int ret = -ENOSPC;
5662
5663         spin_lock(&block_rsv->lock);
5664         if (block_rsv->reserved < block_rsv->size)
5665                 num_bytes = block_rsv->size - block_rsv->reserved;
5666         if (block_rsv->qgroup_rsv_reserved < block_rsv->qgroup_rsv_size)
5667                 qgroup_num_bytes = block_rsv->qgroup_rsv_size -
5668                                    block_rsv->qgroup_rsv_reserved;
5669         spin_unlock(&block_rsv->lock);
5670
5671         if (num_bytes == 0)
5672                 return 0;
5673
5674         ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_num_bytes, true);
5675         if (ret)
5676                 return ret;
5677         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5678         if (!ret) {
5679                 block_rsv_add_bytes(block_rsv, num_bytes, false);
5680                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5681                                               btrfs_ino(inode), num_bytes, 1);
5682
5683                 /* Don't forget to increase qgroup_rsv_reserved */
5684                 spin_lock(&block_rsv->lock);
5685                 block_rsv->qgroup_rsv_reserved += qgroup_num_bytes;
5686                 spin_unlock(&block_rsv->lock);
5687         } else
5688                 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
5689         return ret;
5690 }
5691
5692 /**
5693  * btrfs_inode_rsv_release - release any excessive reservation.
5694  * @inode - the inode we need to release from.
5695  * @qgroup_free - free or convert qgroup meta.
5696  *   Unlike normal operation, qgroup meta reservation needs to know if we are
5697  *   freeing qgroup reservation or just converting it into per-trans.  Normally
5698  *   @qgroup_free is true for error handling, and false for normal release.
5699  *
5700  * This is the same as btrfs_block_rsv_release, except that it handles the
5701  * tracepoint for the reservation.
5702  */
5703 static void btrfs_inode_rsv_release(struct btrfs_inode *inode, bool qgroup_free)
5704 {
5705         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5706         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5707         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5708         u64 released = 0;
5709         u64 qgroup_to_release = 0;
5710
5711         /*
5712          * Since we statically set the block_rsv->size we just want to say we
5713          * are releasing 0 bytes, and then we'll just get the reservation over
5714          * the size free'd.
5715          */
5716         released = block_rsv_release_bytes(fs_info, block_rsv, global_rsv, 0,
5717                                            &qgroup_to_release);
5718         if (released > 0)
5719                 trace_btrfs_space_reservation(fs_info, "delalloc",
5720                                               btrfs_ino(inode), released, 0);
5721         if (qgroup_free)
5722                 btrfs_qgroup_free_meta_prealloc(inode->root, qgroup_to_release);
5723         else
5724                 btrfs_qgroup_convert_reserved_meta(inode->root,
5725                                                    qgroup_to_release);
5726 }
5727
5728 void btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
5729                              struct btrfs_block_rsv *block_rsv,
5730                              u64 num_bytes)
5731 {
5732         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5733
5734         if (global_rsv == block_rsv ||
5735             block_rsv->space_info != global_rsv->space_info)
5736                 global_rsv = NULL;
5737         block_rsv_release_bytes(fs_info, block_rsv, global_rsv, num_bytes, NULL);
5738 }
5739
5740 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5741 {
5742         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5743         struct btrfs_space_info *sinfo = block_rsv->space_info;
5744         u64 num_bytes;
5745
5746         /*
5747          * The global block rsv is based on the size of the extent tree, the
5748          * checksum tree and the root tree.  If the fs is empty we want to set
5749          * it to a minimal amount for safety.
5750          */
5751         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5752                 btrfs_root_used(&fs_info->csum_root->root_item) +
5753                 btrfs_root_used(&fs_info->tree_root->root_item);
5754         num_bytes = max_t(u64, num_bytes, SZ_16M);
5755
5756         spin_lock(&sinfo->lock);
5757         spin_lock(&block_rsv->lock);
5758
5759         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5760
5761         if (block_rsv->reserved < block_rsv->size) {
5762                 num_bytes = btrfs_space_info_used(sinfo, true);
5763                 if (sinfo->total_bytes > num_bytes) {
5764                         num_bytes = sinfo->total_bytes - num_bytes;
5765                         num_bytes = min(num_bytes,
5766                                         block_rsv->size - block_rsv->reserved);
5767                         block_rsv->reserved += num_bytes;
5768                         update_bytes_may_use(sinfo, num_bytes);
5769                         trace_btrfs_space_reservation(fs_info, "space_info",
5770                                                       sinfo->flags, num_bytes,
5771                                                       1);
5772                 }
5773         } else if (block_rsv->reserved > block_rsv->size) {
5774                 num_bytes = block_rsv->reserved - block_rsv->size;
5775                 update_bytes_may_use(sinfo, -num_bytes);
5776                 trace_btrfs_space_reservation(fs_info, "space_info",
5777                                       sinfo->flags, num_bytes, 0);
5778                 block_rsv->reserved = block_rsv->size;
5779         }
5780
5781         if (block_rsv->reserved == block_rsv->size)
5782                 block_rsv->full = 1;
5783         else
5784                 block_rsv->full = 0;
5785
5786         spin_unlock(&block_rsv->lock);
5787         spin_unlock(&sinfo->lock);
5788 }
5789
5790 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5791 {
5792         struct btrfs_space_info *space_info;
5793
5794         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5795         fs_info->chunk_block_rsv.space_info = space_info;
5796
5797         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5798         fs_info->global_block_rsv.space_info = space_info;
5799         fs_info->trans_block_rsv.space_info = space_info;
5800         fs_info->empty_block_rsv.space_info = space_info;
5801         fs_info->delayed_block_rsv.space_info = space_info;
5802
5803         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5804         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5805         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5806         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5807         if (fs_info->quota_root)
5808                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5809         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5810
5811         update_global_block_rsv(fs_info);
5812 }
5813
5814 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5815 {
5816         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5817                                 (u64)-1, NULL);
5818         WARN_ON(fs_info->trans_block_rsv.size > 0);
5819         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5820         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5821         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5822         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5823         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5824 }
5825
5826
5827 /*
5828  * To be called after all the new block groups attached to the transaction
5829  * handle have been created (btrfs_create_pending_block_groups()).
5830  */
5831 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5832 {
5833         struct btrfs_fs_info *fs_info = trans->fs_info;
5834
5835         if (!trans->chunk_bytes_reserved)
5836                 return;
5837
5838         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5839
5840         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5841                                 trans->chunk_bytes_reserved, NULL);
5842         trans->chunk_bytes_reserved = 0;
5843 }
5844
5845 /*
5846  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5847  * root: the root of the parent directory
5848  * rsv: block reservation
5849  * items: the number of items that we need do reservation
5850  * use_global_rsv: allow fallback to the global block reservation
5851  *
5852  * This function is used to reserve the space for snapshot/subvolume
5853  * creation and deletion. Those operations are different with the
5854  * common file/directory operations, they change two fs/file trees
5855  * and root tree, the number of items that the qgroup reserves is
5856  * different with the free space reservation. So we can not use
5857  * the space reservation mechanism in start_transaction().
5858  */
5859 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5860                                      struct btrfs_block_rsv *rsv, int items,
5861                                      bool use_global_rsv)
5862 {
5863         u64 qgroup_num_bytes = 0;
5864         u64 num_bytes;
5865         int ret;
5866         struct btrfs_fs_info *fs_info = root->fs_info;
5867         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5868
5869         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
5870                 /* One for parent inode, two for dir entries */
5871                 qgroup_num_bytes = 3 * fs_info->nodesize;
5872                 ret = btrfs_qgroup_reserve_meta_prealloc(root,
5873                                 qgroup_num_bytes, true);
5874                 if (ret)
5875                         return ret;
5876         }
5877
5878         num_bytes = btrfs_calc_trans_metadata_size(fs_info, items);
5879         rsv->space_info = __find_space_info(fs_info,
5880                                             BTRFS_BLOCK_GROUP_METADATA);
5881         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5882                                   BTRFS_RESERVE_FLUSH_ALL);
5883
5884         if (ret == -ENOSPC && use_global_rsv)
5885                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, true);
5886
5887         if (ret && qgroup_num_bytes)
5888                 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
5889
5890         return ret;
5891 }
5892
5893 void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
5894                                       struct btrfs_block_rsv *rsv)
5895 {
5896         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5897 }
5898
5899 static void btrfs_calculate_inode_block_rsv_size(struct btrfs_fs_info *fs_info,
5900                                                  struct btrfs_inode *inode)
5901 {
5902         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5903         u64 reserve_size = 0;
5904         u64 qgroup_rsv_size = 0;
5905         u64 csum_leaves;
5906         unsigned outstanding_extents;
5907
5908         lockdep_assert_held(&inode->lock);
5909         outstanding_extents = inode->outstanding_extents;
5910         if (outstanding_extents)
5911                 reserve_size = btrfs_calc_trans_metadata_size(fs_info,
5912                                                 outstanding_extents + 1);
5913         csum_leaves = btrfs_csum_bytes_to_leaves(fs_info,
5914                                                  inode->csum_bytes);
5915         reserve_size += btrfs_calc_trans_metadata_size(fs_info,
5916                                                        csum_leaves);
5917         /*
5918          * For qgroup rsv, the calculation is very simple:
5919          * account one nodesize for each outstanding extent
5920          *
5921          * This is overestimating in most cases.
5922          */
5923         qgroup_rsv_size = outstanding_extents * fs_info->nodesize;
5924
5925         spin_lock(&block_rsv->lock);
5926         block_rsv->size = reserve_size;
5927         block_rsv->qgroup_rsv_size = qgroup_rsv_size;
5928         spin_unlock(&block_rsv->lock);
5929 }
5930
5931 int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
5932 {
5933         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5934         unsigned nr_extents;
5935         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5936         int ret = 0;
5937         bool delalloc_lock = true;
5938
5939         /* If we are a free space inode we need to not flush since we will be in
5940          * the middle of a transaction commit.  We also don't need the delalloc
5941          * mutex since we won't race with anybody.  We need this mostly to make
5942          * lockdep shut its filthy mouth.
5943          *
5944          * If we have a transaction open (can happen if we call truncate_block
5945          * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5946          */
5947         if (btrfs_is_free_space_inode(inode)) {
5948                 flush = BTRFS_RESERVE_NO_FLUSH;
5949                 delalloc_lock = false;
5950         } else {
5951                 if (current->journal_info)
5952                         flush = BTRFS_RESERVE_FLUSH_LIMIT;
5953
5954                 if (btrfs_transaction_in_commit(fs_info))
5955                         schedule_timeout(1);
5956         }
5957
5958         if (delalloc_lock)
5959                 mutex_lock(&inode->delalloc_mutex);
5960
5961         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
5962
5963         /* Add our new extents and calculate the new rsv size. */
5964         spin_lock(&inode->lock);
5965         nr_extents = count_max_extents(num_bytes);
5966         btrfs_mod_outstanding_extents(inode, nr_extents);
5967         inode->csum_bytes += num_bytes;
5968         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5969         spin_unlock(&inode->lock);
5970
5971         ret = btrfs_inode_rsv_refill(inode, flush);
5972         if (unlikely(ret))
5973                 goto out_fail;
5974
5975         if (delalloc_lock)
5976                 mutex_unlock(&inode->delalloc_mutex);
5977         return 0;
5978
5979 out_fail:
5980         spin_lock(&inode->lock);
5981         nr_extents = count_max_extents(num_bytes);
5982         btrfs_mod_outstanding_extents(inode, -nr_extents);
5983         inode->csum_bytes -= num_bytes;
5984         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
5985         spin_unlock(&inode->lock);
5986
5987         btrfs_inode_rsv_release(inode, true);
5988         if (delalloc_lock)
5989                 mutex_unlock(&inode->delalloc_mutex);
5990         return ret;
5991 }
5992
5993 /**
5994  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5995  * @inode: the inode to release the reservation for.
5996  * @num_bytes: the number of bytes we are releasing.
5997  * @qgroup_free: free qgroup reservation or convert it to per-trans reservation
5998  *
5999  * This will release the metadata reservation for an inode.  This can be called
6000  * once we complete IO for a given set of bytes to release their metadata
6001  * reservations, or on error for the same reason.
6002  */
6003 void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes,
6004                                      bool qgroup_free)
6005 {
6006         struct btrfs_fs_info *fs_info = inode->root->fs_info;
6007
6008         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
6009         spin_lock(&inode->lock);
6010         inode->csum_bytes -= num_bytes;
6011         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6012         spin_unlock(&inode->lock);
6013
6014         if (btrfs_is_testing(fs_info))
6015                 return;
6016
6017         btrfs_inode_rsv_release(inode, qgroup_free);
6018 }
6019
6020 /**
6021  * btrfs_delalloc_release_extents - release our outstanding_extents
6022  * @inode: the inode to balance the reservation for.
6023  * @num_bytes: the number of bytes we originally reserved with
6024  * @qgroup_free: do we need to free qgroup meta reservation or convert them.
6025  *
6026  * When we reserve space we increase outstanding_extents for the extents we may
6027  * add.  Once we've set the range as delalloc or created our ordered extents we
6028  * have outstanding_extents to track the real usage, so we use this to free our
6029  * temporarily tracked outstanding_extents.  This _must_ be used in conjunction
6030  * with btrfs_delalloc_reserve_metadata.
6031  */
6032 void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes,
6033                                     bool qgroup_free)
6034 {
6035         struct btrfs_fs_info *fs_info = inode->root->fs_info;
6036         unsigned num_extents;
6037
6038         spin_lock(&inode->lock);
6039         num_extents = count_max_extents(num_bytes);
6040         btrfs_mod_outstanding_extents(inode, -num_extents);
6041         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6042         spin_unlock(&inode->lock);
6043
6044         if (btrfs_is_testing(fs_info))
6045                 return;
6046
6047         btrfs_inode_rsv_release(inode, qgroup_free);
6048 }
6049
6050 /**
6051  * btrfs_delalloc_reserve_space - reserve data and metadata space for
6052  * delalloc
6053  * @inode: inode we're writing to
6054  * @start: start range we are writing to
6055  * @len: how long the range we are writing to
6056  * @reserved: mandatory parameter, record actually reserved qgroup ranges of
6057  *            current reservation.
6058  *
6059  * This will do the following things
6060  *
6061  * o reserve space in data space info for num bytes
6062  *   and reserve precious corresponding qgroup space
6063  *   (Done in check_data_free_space)
6064  *
6065  * o reserve space for metadata space, based on the number of outstanding
6066  *   extents and how much csums will be needed
6067  *   also reserve metadata space in a per root over-reserve method.
6068  * o add to the inodes->delalloc_bytes
6069  * o add it to the fs_info's delalloc inodes list.
6070  *   (Above 3 all done in delalloc_reserve_metadata)
6071  *
6072  * Return 0 for success
6073  * Return <0 for error(-ENOSPC or -EQUOT)
6074  */
6075 int btrfs_delalloc_reserve_space(struct inode *inode,
6076                         struct extent_changeset **reserved, u64 start, u64 len)
6077 {
6078         int ret;
6079
6080         ret = btrfs_check_data_free_space(inode, reserved, start, len);
6081         if (ret < 0)
6082                 return ret;
6083         ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len);
6084         if (ret < 0)
6085                 btrfs_free_reserved_data_space(inode, *reserved, start, len);
6086         return ret;
6087 }
6088
6089 /**
6090  * btrfs_delalloc_release_space - release data and metadata space for delalloc
6091  * @inode: inode we're releasing space for
6092  * @start: start position of the space already reserved
6093  * @len: the len of the space already reserved
6094  * @release_bytes: the len of the space we consumed or didn't use
6095  *
6096  * This function will release the metadata space that was not used and will
6097  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6098  * list if there are no delalloc bytes left.
6099  * Also it will handle the qgroup reserved space.
6100  */
6101 void btrfs_delalloc_release_space(struct inode *inode,
6102                                   struct extent_changeset *reserved,
6103                                   u64 start, u64 len, bool qgroup_free)
6104 {
6105         btrfs_delalloc_release_metadata(BTRFS_I(inode), len, qgroup_free);
6106         btrfs_free_reserved_data_space(inode, reserved, start, len);
6107 }
6108
6109 static int update_block_group(struct btrfs_trans_handle *trans,
6110                               struct btrfs_fs_info *info, u64 bytenr,
6111                               u64 num_bytes, int alloc)
6112 {
6113         struct btrfs_block_group_cache *cache = NULL;
6114         u64 total = num_bytes;
6115         u64 old_val;
6116         u64 byte_in_group;
6117         int factor;
6118
6119         /* block accounting for super block */
6120         spin_lock(&info->delalloc_root_lock);
6121         old_val = btrfs_super_bytes_used(info->super_copy);
6122         if (alloc)
6123                 old_val += num_bytes;
6124         else
6125                 old_val -= num_bytes;
6126         btrfs_set_super_bytes_used(info->super_copy, old_val);
6127         spin_unlock(&info->delalloc_root_lock);
6128
6129         while (total) {
6130                 cache = btrfs_lookup_block_group(info, bytenr);
6131                 if (!cache)
6132                         return -ENOENT;
6133                 factor = btrfs_bg_type_to_factor(cache->flags);
6134
6135                 /*
6136                  * If this block group has free space cache written out, we
6137                  * need to make sure to load it if we are removing space.  This
6138                  * is because we need the unpinning stage to actually add the
6139                  * space back to the block group, otherwise we will leak space.
6140                  */
6141                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6142                         cache_block_group(cache, 1);
6143
6144                 byte_in_group = bytenr - cache->key.objectid;
6145                 WARN_ON(byte_in_group > cache->key.offset);
6146
6147                 spin_lock(&cache->space_info->lock);
6148                 spin_lock(&cache->lock);
6149
6150                 if (btrfs_test_opt(info, SPACE_CACHE) &&
6151                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6152                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6153
6154                 old_val = btrfs_block_group_used(&cache->item);
6155                 num_bytes = min(total, cache->key.offset - byte_in_group);
6156                 if (alloc) {
6157                         old_val += num_bytes;
6158                         btrfs_set_block_group_used(&cache->item, old_val);
6159                         cache->reserved -= num_bytes;
6160                         cache->space_info->bytes_reserved -= num_bytes;
6161                         cache->space_info->bytes_used += num_bytes;
6162                         cache->space_info->disk_used += num_bytes * factor;
6163                         spin_unlock(&cache->lock);
6164                         spin_unlock(&cache->space_info->lock);
6165                 } else {
6166                         old_val -= num_bytes;
6167                         btrfs_set_block_group_used(&cache->item, old_val);
6168                         cache->pinned += num_bytes;
6169                         update_bytes_pinned(cache->space_info, num_bytes);
6170                         cache->space_info->bytes_used -= num_bytes;
6171                         cache->space_info->disk_used -= num_bytes * factor;
6172                         spin_unlock(&cache->lock);
6173                         spin_unlock(&cache->space_info->lock);
6174
6175                         trace_btrfs_space_reservation(info, "pinned",
6176                                                       cache->space_info->flags,
6177                                                       num_bytes, 1);
6178                         percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
6179                                            num_bytes,
6180                                            BTRFS_TOTAL_BYTES_PINNED_BATCH);
6181                         set_extent_dirty(info->pinned_extents,
6182                                          bytenr, bytenr + num_bytes - 1,
6183                                          GFP_NOFS | __GFP_NOFAIL);
6184                 }
6185
6186                 spin_lock(&trans->transaction->dirty_bgs_lock);
6187                 if (list_empty(&cache->dirty_list)) {
6188                         list_add_tail(&cache->dirty_list,
6189                                       &trans->transaction->dirty_bgs);
6190                         trans->transaction->num_dirty_bgs++;
6191                         btrfs_get_block_group(cache);
6192                 }
6193                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6194
6195                 /*
6196                  * No longer have used bytes in this block group, queue it for
6197                  * deletion. We do this after adding the block group to the
6198                  * dirty list to avoid races between cleaner kthread and space
6199                  * cache writeout.
6200                  */
6201                 if (!alloc && old_val == 0)
6202                         btrfs_mark_bg_unused(cache);
6203
6204                 btrfs_put_block_group(cache);
6205                 total -= num_bytes;
6206                 bytenr += num_bytes;
6207         }
6208         return 0;
6209 }
6210
6211 static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
6212 {
6213         struct btrfs_block_group_cache *cache;
6214         u64 bytenr;
6215
6216         spin_lock(&fs_info->block_group_cache_lock);
6217         bytenr = fs_info->first_logical_byte;
6218         spin_unlock(&fs_info->block_group_cache_lock);
6219
6220         if (bytenr < (u64)-1)
6221                 return bytenr;
6222
6223         cache = btrfs_lookup_first_block_group(fs_info, search_start);
6224         if (!cache)
6225                 return 0;
6226
6227         bytenr = cache->key.objectid;
6228         btrfs_put_block_group(cache);
6229
6230         return bytenr;
6231 }
6232
6233 static int pin_down_extent(struct btrfs_fs_info *fs_info,
6234                            struct btrfs_block_group_cache *cache,
6235                            u64 bytenr, u64 num_bytes, int reserved)
6236 {
6237         spin_lock(&cache->space_info->lock);
6238         spin_lock(&cache->lock);
6239         cache->pinned += num_bytes;
6240         update_bytes_pinned(cache->space_info, num_bytes);
6241         if (reserved) {
6242                 cache->reserved -= num_bytes;
6243                 cache->space_info->bytes_reserved -= num_bytes;
6244         }
6245         spin_unlock(&cache->lock);
6246         spin_unlock(&cache->space_info->lock);
6247
6248         trace_btrfs_space_reservation(fs_info, "pinned",
6249                                       cache->space_info->flags, num_bytes, 1);
6250         percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
6251                     num_bytes, BTRFS_TOTAL_BYTES_PINNED_BATCH);
6252         set_extent_dirty(fs_info->pinned_extents, bytenr,
6253                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6254         return 0;
6255 }
6256
6257 /*
6258  * this function must be called within transaction
6259  */
6260 int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
6261                      u64 bytenr, u64 num_bytes, int reserved)
6262 {
6263         struct btrfs_block_group_cache *cache;
6264
6265         cache = btrfs_lookup_block_group(fs_info, bytenr);
6266         BUG_ON(!cache); /* Logic error */
6267
6268         pin_down_extent(fs_info, cache, bytenr, num_bytes, reserved);
6269
6270         btrfs_put_block_group(cache);
6271         return 0;
6272 }
6273
6274 /*
6275  * this function must be called within transaction
6276  */
6277 int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
6278                                     u64 bytenr, u64 num_bytes)
6279 {
6280         struct btrfs_block_group_cache *cache;
6281         int ret;
6282
6283         cache = btrfs_lookup_block_group(fs_info, bytenr);
6284         if (!cache)
6285                 return -EINVAL;
6286
6287         /*
6288          * pull in the free space cache (if any) so that our pin
6289          * removes the free space from the cache.  We have load_only set
6290          * to one because the slow code to read in the free extents does check
6291          * the pinned extents.
6292          */
6293         cache_block_group(cache, 1);
6294
6295         pin_down_extent(fs_info, cache, bytenr, num_bytes, 0);
6296
6297         /* remove us from the free space cache (if we're there at all) */
6298         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6299         btrfs_put_block_group(cache);
6300         return ret;
6301 }
6302
6303 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
6304                                    u64 start, u64 num_bytes)
6305 {
6306         int ret;
6307         struct btrfs_block_group_cache *block_group;
6308         struct btrfs_caching_control *caching_ctl;
6309
6310         block_group = btrfs_lookup_block_group(fs_info, start);
6311         if (!block_group)
6312                 return -EINVAL;
6313
6314         cache_block_group(block_group, 0);
6315         caching_ctl = get_caching_control(block_group);
6316
6317         if (!caching_ctl) {
6318                 /* Logic error */
6319                 BUG_ON(!block_group_cache_done(block_group));
6320                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6321         } else {
6322                 mutex_lock(&caching_ctl->mutex);
6323
6324                 if (start >= caching_ctl->progress) {
6325                         ret = add_excluded_extent(fs_info, start, num_bytes);
6326                 } else if (start + num_bytes <= caching_ctl->progress) {
6327                         ret = btrfs_remove_free_space(block_group,
6328                                                       start, num_bytes);
6329                 } else {
6330                         num_bytes = caching_ctl->progress - start;
6331                         ret = btrfs_remove_free_space(block_group,
6332                                                       start, num_bytes);
6333                         if (ret)
6334                                 goto out_lock;
6335
6336                         num_bytes = (start + num_bytes) -
6337                                 caching_ctl->progress;
6338                         start = caching_ctl->progress;
6339                         ret = add_excluded_extent(fs_info, start, num_bytes);
6340                 }
6341 out_lock:
6342                 mutex_unlock(&caching_ctl->mutex);
6343                 put_caching_control(caching_ctl);
6344         }
6345         btrfs_put_block_group(block_group);
6346         return ret;
6347 }
6348
6349 int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
6350                                  struct extent_buffer *eb)
6351 {
6352         struct btrfs_file_extent_item *item;
6353         struct btrfs_key key;
6354         int found_type;
6355         int i;
6356         int ret = 0;
6357
6358         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
6359                 return 0;
6360
6361         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6362                 btrfs_item_key_to_cpu(eb, &key, i);
6363                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6364                         continue;
6365                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6366                 found_type = btrfs_file_extent_type(eb, item);
6367                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6368                         continue;
6369                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6370                         continue;
6371                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6372                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6373                 ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
6374                 if (ret)
6375                         break;
6376         }
6377
6378         return ret;
6379 }
6380
6381 static void
6382 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6383 {
6384         atomic_inc(&bg->reservations);
6385 }
6386
6387 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6388                                         const u64 start)
6389 {
6390         struct btrfs_block_group_cache *bg;
6391
6392         bg = btrfs_lookup_block_group(fs_info, start);
6393         ASSERT(bg);
6394         if (atomic_dec_and_test(&bg->reservations))
6395                 wake_up_var(&bg->reservations);
6396         btrfs_put_block_group(bg);
6397 }
6398
6399 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6400 {
6401         struct btrfs_space_info *space_info = bg->space_info;
6402
6403         ASSERT(bg->ro);
6404
6405         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6406                 return;
6407
6408         /*
6409          * Our block group is read only but before we set it to read only,
6410          * some task might have had allocated an extent from it already, but it
6411          * has not yet created a respective ordered extent (and added it to a
6412          * root's list of ordered extents).
6413          * Therefore wait for any task currently allocating extents, since the
6414          * block group's reservations counter is incremented while a read lock
6415          * on the groups' semaphore is held and decremented after releasing
6416          * the read access on that semaphore and creating the ordered extent.
6417          */
6418         down_write(&space_info->groups_sem);
6419         up_write(&space_info->groups_sem);
6420
6421         wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
6422 }
6423
6424 /**
6425  * btrfs_add_reserved_bytes - update the block_group and space info counters
6426  * @cache:      The cache we are manipulating
6427  * @ram_bytes:  The number of bytes of file content, and will be same to
6428  *              @num_bytes except for the compress path.
6429  * @num_bytes:  The number of bytes in question
6430  * @delalloc:   The blocks are allocated for the delalloc write
6431  *
6432  * This is called by the allocator when it reserves space. If this is a
6433  * reservation and the block group has become read only we cannot make the
6434  * reservation and return -EAGAIN, otherwise this function always succeeds.
6435  */
6436 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6437                                     u64 ram_bytes, u64 num_bytes, int delalloc)
6438 {
6439         struct btrfs_space_info *space_info = cache->space_info;
6440         int ret = 0;
6441
6442         spin_lock(&space_info->lock);
6443         spin_lock(&cache->lock);
6444         if (cache->ro) {
6445                 ret = -EAGAIN;
6446         } else {
6447                 cache->reserved += num_bytes;
6448                 space_info->bytes_reserved += num_bytes;
6449                 update_bytes_may_use(space_info, -ram_bytes);
6450                 if (delalloc)
6451                         cache->delalloc_bytes += num_bytes;
6452         }
6453         spin_unlock(&cache->lock);
6454         spin_unlock(&space_info->lock);
6455         return ret;
6456 }
6457
6458 /**
6459  * btrfs_free_reserved_bytes - update the block_group and space info counters
6460  * @cache:      The cache we are manipulating
6461  * @num_bytes:  The number of bytes in question
6462  * @delalloc:   The blocks are allocated for the delalloc write
6463  *
6464  * This is called by somebody who is freeing space that was never actually used
6465  * on disk.  For example if you reserve some space for a new leaf in transaction
6466  * A and before transaction A commits you free that leaf, you call this with
6467  * reserve set to 0 in order to clear the reservation.
6468  */
6469
6470 static void btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6471                                       u64 num_bytes, int delalloc)
6472 {
6473         struct btrfs_space_info *space_info = cache->space_info;
6474
6475         spin_lock(&space_info->lock);
6476         spin_lock(&cache->lock);
6477         if (cache->ro)
6478                 space_info->bytes_readonly += num_bytes;
6479         cache->reserved -= num_bytes;
6480         space_info->bytes_reserved -= num_bytes;
6481         space_info->max_extent_size = 0;
6482
6483         if (delalloc)
6484                 cache->delalloc_bytes -= num_bytes;
6485         spin_unlock(&cache->lock);
6486         spin_unlock(&space_info->lock);
6487 }
6488 void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
6489 {
6490         struct btrfs_caching_control *next;
6491         struct btrfs_caching_control *caching_ctl;
6492         struct btrfs_block_group_cache *cache;
6493
6494         down_write(&fs_info->commit_root_sem);
6495
6496         list_for_each_entry_safe(caching_ctl, next,
6497                                  &fs_info->caching_block_groups, list) {
6498                 cache = caching_ctl->block_group;
6499                 if (block_group_cache_done(cache)) {
6500                         cache->last_byte_to_unpin = (u64)-1;
6501                         list_del_init(&caching_ctl->list);
6502                         put_caching_control(caching_ctl);
6503                 } else {
6504                         cache->last_byte_to_unpin = caching_ctl->progress;
6505                 }
6506         }
6507
6508         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6509                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6510         else
6511                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6512
6513         up_write(&fs_info->commit_root_sem);
6514
6515         update_global_block_rsv(fs_info);
6516 }
6517
6518 /*
6519  * Returns the free cluster for the given space info and sets empty_cluster to
6520  * what it should be based on the mount options.
6521  */
6522 static struct btrfs_free_cluster *
6523 fetch_cluster_info(struct btrfs_fs_info *fs_info,
6524                    struct btrfs_space_info *space_info, u64 *empty_cluster)
6525 {
6526         struct btrfs_free_cluster *ret = NULL;
6527
6528         *empty_cluster = 0;
6529         if (btrfs_mixed_space_info(space_info))
6530                 return ret;
6531
6532         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6533                 ret = &fs_info->meta_alloc_cluster;
6534                 if (btrfs_test_opt(fs_info, SSD))
6535                         *empty_cluster = SZ_2M;
6536                 else
6537                         *empty_cluster = SZ_64K;
6538         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
6539                    btrfs_test_opt(fs_info, SSD_SPREAD)) {
6540                 *empty_cluster = SZ_2M;
6541                 ret = &fs_info->data_alloc_cluster;
6542         }
6543
6544         return ret;
6545 }
6546
6547 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
6548                               u64 start, u64 end,
6549                               const bool return_free_space)
6550 {
6551         struct btrfs_block_group_cache *cache = NULL;
6552         struct btrfs_space_info *space_info;
6553         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6554         struct btrfs_free_cluster *cluster = NULL;
6555         u64 len;
6556         u64 total_unpinned = 0;
6557         u64 empty_cluster = 0;
6558         bool readonly;
6559
6560         while (start <= end) {
6561                 readonly = false;
6562                 if (!cache ||
6563                     start >= cache->key.objectid + cache->key.offset) {
6564                         if (cache)
6565                                 btrfs_put_block_group(cache);
6566                         total_unpinned = 0;
6567                         cache = btrfs_lookup_block_group(fs_info, start);
6568                         BUG_ON(!cache); /* Logic error */
6569
6570                         cluster = fetch_cluster_info(fs_info,
6571                                                      cache->space_info,
6572                                                      &empty_cluster);
6573                         empty_cluster <<= 1;
6574                 }
6575
6576                 len = cache->key.objectid + cache->key.offset - start;
6577                 len = min(len, end + 1 - start);
6578
6579                 if (start < cache->last_byte_to_unpin) {
6580                         len = min(len, cache->last_byte_to_unpin - start);
6581                         if (return_free_space)
6582                                 btrfs_add_free_space(cache, start, len);
6583                 }
6584
6585                 start += len;
6586                 total_unpinned += len;
6587                 space_info = cache->space_info;
6588
6589                 /*
6590                  * If this space cluster has been marked as fragmented and we've
6591                  * unpinned enough in this block group to potentially allow a
6592                  * cluster to be created inside of it go ahead and clear the
6593                  * fragmented check.
6594                  */
6595                 if (cluster && cluster->fragmented &&
6596                     total_unpinned > empty_cluster) {
6597                         spin_lock(&cluster->lock);
6598                         cluster->fragmented = 0;
6599                         spin_unlock(&cluster->lock);
6600                 }
6601
6602                 spin_lock(&space_info->lock);
6603                 spin_lock(&cache->lock);
6604                 cache->pinned -= len;
6605                 update_bytes_pinned(space_info, -len);
6606
6607                 trace_btrfs_space_reservation(fs_info, "pinned",
6608                                               space_info->flags, len, 0);
6609                 space_info->max_extent_size = 0;
6610                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
6611                             -len, BTRFS_TOTAL_BYTES_PINNED_BATCH);
6612                 if (cache->ro) {
6613                         space_info->bytes_readonly += len;
6614                         readonly = true;
6615                 }
6616                 spin_unlock(&cache->lock);
6617                 if (!readonly && return_free_space &&
6618                     global_rsv->space_info == space_info) {
6619                         u64 to_add = len;
6620
6621                         spin_lock(&global_rsv->lock);
6622                         if (!global_rsv->full) {
6623                                 to_add = min(len, global_rsv->size -
6624                                              global_rsv->reserved);
6625                                 global_rsv->reserved += to_add;
6626                                 update_bytes_may_use(space_info, to_add);
6627                                 if (global_rsv->reserved >= global_rsv->size)
6628                                         global_rsv->full = 1;
6629                                 trace_btrfs_space_reservation(fs_info,
6630                                                               "space_info",
6631                                                               space_info->flags,
6632                                                               to_add, 1);
6633                                 len -= to_add;
6634                         }
6635                         spin_unlock(&global_rsv->lock);
6636                         /* Add to any tickets we may have */
6637                         if (len)
6638                                 space_info_add_new_bytes(fs_info, space_info,
6639                                                          len);
6640                 }
6641                 spin_unlock(&space_info->lock);
6642         }
6643
6644         if (cache)
6645                 btrfs_put_block_group(cache);
6646         return 0;
6647 }
6648
6649 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
6650 {
6651         struct btrfs_fs_info *fs_info = trans->fs_info;
6652         struct btrfs_block_group_cache *block_group, *tmp;
6653         struct list_head *deleted_bgs;
6654         struct extent_io_tree *unpin;
6655         u64 start;
6656         u64 end;
6657         int ret;
6658
6659         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6660                 unpin = &fs_info->freed_extents[1];
6661         else
6662                 unpin = &fs_info->freed_extents[0];
6663
6664         while (!trans->aborted) {
6665                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6666                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6667                                             EXTENT_DIRTY, NULL);
6668                 if (ret) {
6669                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6670                         break;
6671                 }
6672
6673                 if (btrfs_test_opt(fs_info, DISCARD))
6674                         ret = btrfs_discard_extent(fs_info, start,
6675                                                    end + 1 - start, NULL);
6676
6677                 clear_extent_dirty(unpin, start, end);
6678                 unpin_extent_range(fs_info, start, end, true);
6679                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6680                 cond_resched();
6681         }
6682
6683         /*
6684          * Transaction is finished.  We don't need the lock anymore.  We
6685          * do need to clean up the block groups in case of a transaction
6686          * abort.
6687          */
6688         deleted_bgs = &trans->transaction->deleted_bgs;
6689         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6690                 u64 trimmed = 0;
6691
6692                 ret = -EROFS;
6693                 if (!trans->aborted)
6694                         ret = btrfs_discard_extent(fs_info,
6695                                                    block_group->key.objectid,
6696                                                    block_group->key.offset,
6697                                                    &trimmed);
6698
6699                 list_del_init(&block_group->bg_list);
6700                 btrfs_put_block_group_trimming(block_group);
6701                 btrfs_put_block_group(block_group);
6702
6703                 if (ret) {
6704                         const char *errstr = btrfs_decode_error(ret);
6705                         btrfs_warn(fs_info,
6706                            "discard failed while removing blockgroup: errno=%d %s",
6707                                    ret, errstr);
6708                 }
6709         }
6710
6711         return 0;
6712 }
6713
6714 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6715                                struct btrfs_delayed_ref_node *node, u64 parent,
6716                                u64 root_objectid, u64 owner_objectid,
6717                                u64 owner_offset, int refs_to_drop,
6718                                struct btrfs_delayed_extent_op *extent_op)
6719 {
6720         struct btrfs_fs_info *info = trans->fs_info;
6721         struct btrfs_key key;
6722         struct btrfs_path *path;
6723         struct btrfs_root *extent_root = info->extent_root;
6724         struct extent_buffer *leaf;
6725         struct btrfs_extent_item *ei;
6726         struct btrfs_extent_inline_ref *iref;
6727         int ret;
6728         int is_data;
6729         int extent_slot = 0;
6730         int found_extent = 0;
6731         int num_to_del = 1;
6732         u32 item_size;
6733         u64 refs;
6734         u64 bytenr = node->bytenr;
6735         u64 num_bytes = node->num_bytes;
6736         int last_ref = 0;
6737         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
6738
6739         path = btrfs_alloc_path();
6740         if (!path)
6741                 return -ENOMEM;
6742
6743         path->reada = READA_FORWARD;
6744         path->leave_spinning = 1;
6745
6746         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6747         BUG_ON(!is_data && refs_to_drop != 1);
6748
6749         if (is_data)
6750                 skinny_metadata = false;
6751
6752         ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
6753                                     parent, root_objectid, owner_objectid,
6754                                     owner_offset);
6755         if (ret == 0) {
6756                 extent_slot = path->slots[0];
6757                 while (extent_slot >= 0) {
6758                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6759                                               extent_slot);
6760                         if (key.objectid != bytenr)
6761                                 break;
6762                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6763                             key.offset == num_bytes) {
6764                                 found_extent = 1;
6765                                 break;
6766                         }
6767                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6768                             key.offset == owner_objectid) {
6769                                 found_extent = 1;
6770                                 break;
6771                         }
6772                         if (path->slots[0] - extent_slot > 5)
6773                                 break;
6774                         extent_slot--;
6775                 }
6776
6777                 if (!found_extent) {
6778                         BUG_ON(iref);
6779                         ret = remove_extent_backref(trans, path, NULL,
6780                                                     refs_to_drop,
6781                                                     is_data, &last_ref);
6782                         if (ret) {
6783                                 btrfs_abort_transaction(trans, ret);
6784                                 goto out;
6785                         }
6786                         btrfs_release_path(path);
6787                         path->leave_spinning = 1;
6788
6789                         key.objectid = bytenr;
6790                         key.type = BTRFS_EXTENT_ITEM_KEY;
6791                         key.offset = num_bytes;
6792
6793                         if (!is_data && skinny_metadata) {
6794                                 key.type = BTRFS_METADATA_ITEM_KEY;
6795                                 key.offset = owner_objectid;
6796                         }
6797
6798                         ret = btrfs_search_slot(trans, extent_root,
6799                                                 &key, path, -1, 1);
6800                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6801                                 /*
6802                                  * Couldn't find our skinny metadata item,
6803                                  * see if we have ye olde extent item.
6804                                  */
6805                                 path->slots[0]--;
6806                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6807                                                       path->slots[0]);
6808                                 if (key.objectid == bytenr &&
6809                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6810                                     key.offset == num_bytes)
6811                                         ret = 0;
6812                         }
6813
6814                         if (ret > 0 && skinny_metadata) {
6815                                 skinny_metadata = false;
6816                                 key.objectid = bytenr;
6817                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6818                                 key.offset = num_bytes;
6819                                 btrfs_release_path(path);
6820                                 ret = btrfs_search_slot(trans, extent_root,
6821                                                         &key, path, -1, 1);
6822                         }
6823
6824                         if (ret) {
6825                                 btrfs_err(info,
6826                                           "umm, got %d back from search, was looking for %llu",
6827                                           ret, bytenr);
6828                                 if (ret > 0)
6829                                         btrfs_print_leaf(path->nodes[0]);
6830                         }
6831                         if (ret < 0) {
6832                                 btrfs_abort_transaction(trans, ret);
6833                                 goto out;
6834                         }
6835                         extent_slot = path->slots[0];
6836                 }
6837         } else if (WARN_ON(ret == -ENOENT)) {
6838                 btrfs_print_leaf(path->nodes[0]);
6839                 btrfs_err(info,
6840                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6841                         bytenr, parent, root_objectid, owner_objectid,
6842                         owner_offset);
6843                 btrfs_abort_transaction(trans, ret);
6844                 goto out;
6845         } else {
6846                 btrfs_abort_transaction(trans, ret);
6847                 goto out;
6848         }
6849
6850         leaf = path->nodes[0];
6851         item_size = btrfs_item_size_nr(leaf, extent_slot);
6852         if (unlikely(item_size < sizeof(*ei))) {
6853                 ret = -EINVAL;
6854                 btrfs_print_v0_err(info);
6855                 btrfs_abort_transaction(trans, ret);
6856                 goto out;
6857         }
6858         ei = btrfs_item_ptr(leaf, extent_slot,
6859                             struct btrfs_extent_item);
6860         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6861             key.type == BTRFS_EXTENT_ITEM_KEY) {
6862                 struct btrfs_tree_block_info *bi;
6863                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6864                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6865                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6866         }
6867
6868         refs = btrfs_extent_refs(leaf, ei);
6869         if (refs < refs_to_drop) {
6870                 btrfs_err(info,
6871                           "trying to drop %d refs but we only have %Lu for bytenr %Lu",
6872                           refs_to_drop, refs, bytenr);
6873                 ret = -EINVAL;
6874                 btrfs_abort_transaction(trans, ret);
6875                 goto out;
6876         }
6877         refs -= refs_to_drop;
6878
6879         if (refs > 0) {
6880                 if (extent_op)
6881                         __run_delayed_extent_op(extent_op, leaf, ei);
6882                 /*
6883                  * In the case of inline back ref, reference count will
6884                  * be updated by remove_extent_backref
6885                  */
6886                 if (iref) {
6887                         BUG_ON(!found_extent);
6888                 } else {
6889                         btrfs_set_extent_refs(leaf, ei, refs);
6890                         btrfs_mark_buffer_dirty(leaf);
6891                 }
6892                 if (found_extent) {
6893                         ret = remove_extent_backref(trans, path, iref,
6894                                                     refs_to_drop, is_data,
6895                                                     &last_ref);
6896                         if (ret) {
6897                                 btrfs_abort_transaction(trans, ret);
6898                                 goto out;
6899                         }
6900                 }
6901         } else {
6902                 if (found_extent) {
6903                         BUG_ON(is_data && refs_to_drop !=
6904                                extent_data_ref_count(path, iref));
6905                         if (iref) {
6906                                 BUG_ON(path->slots[0] != extent_slot);
6907                         } else {
6908                                 BUG_ON(path->slots[0] != extent_slot + 1);
6909                                 path->slots[0] = extent_slot;
6910                                 num_to_del = 2;
6911                         }
6912                 }
6913
6914                 last_ref = 1;
6915                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6916                                       num_to_del);
6917                 if (ret) {
6918                         btrfs_abort_transaction(trans, ret);
6919                         goto out;
6920                 }
6921                 btrfs_release_path(path);
6922
6923                 if (is_data) {
6924                         ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
6925                         if (ret) {
6926                                 btrfs_abort_transaction(trans, ret);
6927                                 goto out;
6928                         }
6929                 }
6930
6931                 ret = add_to_free_space_tree(trans, bytenr, num_bytes);
6932                 if (ret) {
6933                         btrfs_abort_transaction(trans, ret);
6934                         goto out;
6935                 }
6936
6937                 ret = update_block_group(trans, info, bytenr, num_bytes, 0);
6938                 if (ret) {
6939                         btrfs_abort_transaction(trans, ret);
6940                         goto out;
6941                 }
6942         }
6943         btrfs_release_path(path);
6944
6945 out:
6946         btrfs_free_path(path);
6947         return ret;
6948 }
6949
6950 /*
6951  * when we free an block, it is possible (and likely) that we free the last
6952  * delayed ref for that extent as well.  This searches the delayed ref tree for
6953  * a given extent, and if there are no other delayed refs to be processed, it
6954  * removes it from the tree.
6955  */
6956 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6957                                       u64 bytenr)
6958 {
6959         struct btrfs_delayed_ref_head *head;
6960         struct btrfs_delayed_ref_root *delayed_refs;
6961         int ret = 0;
6962
6963         delayed_refs = &trans->transaction->delayed_refs;
6964         spin_lock(&delayed_refs->lock);
6965         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
6966         if (!head)
6967                 goto out_delayed_unlock;
6968
6969         spin_lock(&head->lock);
6970         if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
6971                 goto out;
6972
6973         if (head->extent_op) {
6974                 if (!head->must_insert_reserved)
6975                         goto out;
6976                 btrfs_free_delayed_extent_op(head->extent_op);
6977                 head->extent_op = NULL;
6978         }
6979
6980         /*
6981          * waiting for the lock here would deadlock.  If someone else has it
6982          * locked they are already in the process of dropping it anyway
6983          */
6984         if (!mutex_trylock(&head->mutex))
6985                 goto out;
6986
6987         /*
6988          * at this point we have a head with no other entries.  Go
6989          * ahead and process it.
6990          */
6991         rb_erase_cached(&head->href_node, &delayed_refs->href_root);
6992         RB_CLEAR_NODE(&head->href_node);
6993         atomic_dec(&delayed_refs->num_entries);
6994
6995         /*
6996          * we don't take a ref on the node because we're removing it from the
6997          * tree, so we just steal the ref the tree was holding.
6998          */
6999         delayed_refs->num_heads--;
7000         if (head->processing == 0)
7001                 delayed_refs->num_heads_ready--;
7002         head->processing = 0;
7003         spin_unlock(&head->lock);
7004         spin_unlock(&delayed_refs->lock);
7005
7006         BUG_ON(head->extent_op);
7007         if (head->must_insert_reserved)
7008                 ret = 1;
7009
7010         mutex_unlock(&head->mutex);
7011         btrfs_put_delayed_ref_head(head);
7012         return ret;
7013 out:
7014         spin_unlock(&head->lock);
7015
7016 out_delayed_unlock:
7017         spin_unlock(&delayed_refs->lock);
7018         return 0;
7019 }
7020
7021 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7022                            struct btrfs_root *root,
7023                            struct extent_buffer *buf,
7024                            u64 parent, int last_ref)
7025 {
7026         struct btrfs_fs_info *fs_info = root->fs_info;
7027         int pin = 1;
7028         int ret;
7029
7030         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7031                 int old_ref_mod, new_ref_mod;
7032
7033                 btrfs_ref_tree_mod(root, buf->start, buf->len, parent,
7034                                    root->root_key.objectid,
7035                                    btrfs_header_level(buf), 0,
7036                                    BTRFS_DROP_DELAYED_REF);
7037                 ret = btrfs_add_delayed_tree_ref(trans, buf->start,
7038                                                  buf->len, parent,
7039                                                  root->root_key.objectid,
7040                                                  btrfs_header_level(buf),
7041                                                  BTRFS_DROP_DELAYED_REF, NULL,
7042                                                  &old_ref_mod, &new_ref_mod);
7043                 BUG_ON(ret); /* -ENOMEM */
7044                 pin = old_ref_mod >= 0 && new_ref_mod < 0;
7045         }
7046
7047         if (last_ref && btrfs_header_generation(buf) == trans->transid) {
7048                 struct btrfs_block_group_cache *cache;
7049
7050                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7051                         ret = check_ref_cleanup(trans, buf->start);
7052                         if (!ret)
7053                                 goto out;
7054                 }
7055
7056                 pin = 0;
7057                 cache = btrfs_lookup_block_group(fs_info, buf->start);
7058
7059                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7060                         pin_down_extent(fs_info, cache, buf->start,
7061                                         buf->len, 1);
7062                         btrfs_put_block_group(cache);
7063                         goto out;
7064                 }
7065
7066                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7067
7068                 btrfs_add_free_space(cache, buf->start, buf->len);
7069                 btrfs_free_reserved_bytes(cache, buf->len, 0);
7070                 btrfs_put_block_group(cache);
7071                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
7072         }
7073 out:
7074         if (pin)
7075                 add_pinned_bytes(fs_info, buf->len, true,
7076                                  root->root_key.objectid);
7077
7078         if (last_ref) {
7079                 /*
7080                  * Deleting the buffer, clear the corrupt flag since it doesn't
7081                  * matter anymore.
7082                  */
7083                 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7084         }
7085 }
7086
7087 /* Can return -ENOMEM */
7088 int btrfs_free_extent(struct btrfs_trans_handle *trans,
7089                       struct btrfs_root *root,
7090                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7091                       u64 owner, u64 offset)
7092 {
7093         struct btrfs_fs_info *fs_info = root->fs_info;
7094         int old_ref_mod, new_ref_mod;
7095         int ret;
7096
7097         if (btrfs_is_testing(fs_info))
7098                 return 0;
7099
7100         if (root_objectid != BTRFS_TREE_LOG_OBJECTID)
7101                 btrfs_ref_tree_mod(root, bytenr, num_bytes, parent,
7102                                    root_objectid, owner, offset,
7103                                    BTRFS_DROP_DELAYED_REF);
7104
7105         /*
7106          * tree log blocks never actually go into the extent allocation
7107          * tree, just update pinning info and exit early.
7108          */
7109         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7110                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7111                 /* unlocks the pinned mutex */
7112                 btrfs_pin_extent(fs_info, bytenr, num_bytes, 1);
7113                 old_ref_mod = new_ref_mod = 0;
7114                 ret = 0;
7115         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7116                 ret = btrfs_add_delayed_tree_ref(trans, bytenr,
7117                                                  num_bytes, parent,
7118                                                  root_objectid, (int)owner,
7119                                                  BTRFS_DROP_DELAYED_REF, NULL,
7120                                                  &old_ref_mod, &new_ref_mod);
7121         } else {
7122                 ret = btrfs_add_delayed_data_ref(trans, bytenr,
7123                                                  num_bytes, parent,
7124                                                  root_objectid, owner, offset,
7125                                                  0, BTRFS_DROP_DELAYED_REF,
7126                                                  &old_ref_mod, &new_ref_mod);
7127         }
7128
7129         if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0) {
7130                 bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
7131
7132                 add_pinned_bytes(fs_info, num_bytes, metadata, root_objectid);
7133         }
7134
7135         return ret;
7136 }
7137
7138 /*
7139  * when we wait for progress in the block group caching, its because
7140  * our allocation attempt failed at least once.  So, we must sleep
7141  * and let some progress happen before we try again.
7142  *
7143  * This function will sleep at least once waiting for new free space to
7144  * show up, and then it will check the block group free space numbers
7145  * for our min num_bytes.  Another option is to have it go ahead
7146  * and look in the rbtree for a free extent of a given size, but this
7147  * is a good start.
7148  *
7149  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7150  * any of the information in this block group.
7151  */
7152 static noinline void
7153 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7154                                 u64 num_bytes)
7155 {
7156         struct btrfs_caching_control *caching_ctl;
7157
7158         caching_ctl = get_caching_control(cache);
7159         if (!caching_ctl)
7160                 return;
7161
7162         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7163                    (cache->free_space_ctl->free_space >= num_bytes));
7164
7165         put_caching_control(caching_ctl);
7166 }
7167
7168 static noinline int
7169 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7170 {
7171         struct btrfs_caching_control *caching_ctl;
7172         int ret = 0;
7173
7174         caching_ctl = get_caching_control(cache);
7175         if (!caching_ctl)
7176                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7177
7178         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7179         if (cache->cached == BTRFS_CACHE_ERROR)
7180                 ret = -EIO;
7181         put_caching_control(caching_ctl);
7182         return ret;
7183 }
7184
7185 enum btrfs_loop_type {
7186         LOOP_CACHING_NOWAIT = 0,
7187         LOOP_CACHING_WAIT = 1,
7188         LOOP_ALLOC_CHUNK = 2,
7189         LOOP_NO_EMPTY_SIZE = 3,
7190 };
7191
7192 static inline void
7193 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7194                        int delalloc)
7195 {
7196         if (delalloc)
7197                 down_read(&cache->data_rwsem);
7198 }
7199
7200 static inline void
7201 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7202                        int delalloc)
7203 {
7204         btrfs_get_block_group(cache);
7205         if (delalloc)
7206                 down_read(&cache->data_rwsem);
7207 }
7208
7209 static struct btrfs_block_group_cache *
7210 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7211                    struct btrfs_free_cluster *cluster,
7212                    int delalloc)
7213 {
7214         struct btrfs_block_group_cache *used_bg = NULL;
7215
7216         spin_lock(&cluster->refill_lock);
7217         while (1) {
7218                 used_bg = cluster->block_group;
7219                 if (!used_bg)
7220                         return NULL;
7221
7222                 if (used_bg == block_group)
7223                         return used_bg;
7224
7225                 btrfs_get_block_group(used_bg);
7226
7227                 if (!delalloc)
7228                         return used_bg;
7229
7230                 if (down_read_trylock(&used_bg->data_rwsem))
7231                         return used_bg;
7232
7233                 spin_unlock(&cluster->refill_lock);
7234
7235                 /* We should only have one-level nested. */
7236                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
7237
7238                 spin_lock(&cluster->refill_lock);
7239                 if (used_bg == cluster->block_group)
7240                         return used_bg;
7241
7242                 up_read(&used_bg->data_rwsem);
7243                 btrfs_put_block_group(used_bg);
7244         }
7245 }
7246
7247 static inline void
7248 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7249                          int delalloc)
7250 {
7251         if (delalloc)
7252                 up_read(&cache->data_rwsem);
7253         btrfs_put_block_group(cache);
7254 }
7255
7256 /*
7257  * Structure used internally for find_free_extent() function.  Wraps needed
7258  * parameters.
7259  */
7260 struct find_free_extent_ctl {
7261         /* Basic allocation info */
7262         u64 ram_bytes;
7263         u64 num_bytes;
7264         u64 empty_size;
7265         u64 flags;
7266         int delalloc;
7267
7268         /* Where to start the search inside the bg */
7269         u64 search_start;
7270
7271         /* For clustered allocation */
7272         u64 empty_cluster;
7273
7274         bool have_caching_bg;
7275         bool orig_have_caching_bg;
7276
7277         /* RAID index, converted from flags */
7278         int index;
7279
7280         /*
7281          * Current loop number, check find_free_extent_update_loop() for details
7282          */
7283         int loop;
7284
7285         /*
7286          * Whether we're refilling a cluster, if true we need to re-search
7287          * current block group but don't try to refill the cluster again.
7288          */
7289         bool retry_clustered;
7290
7291         /*
7292          * Whether we're updating free space cache, if true we need to re-search
7293          * current block group but don't try updating free space cache again.
7294          */
7295         bool retry_unclustered;
7296
7297         /* If current block group is cached */
7298         int cached;
7299
7300         /* Max contiguous hole found */
7301         u64 max_extent_size;
7302
7303         /* Total free space from free space cache, not always contiguous */
7304         u64 total_free_space;
7305
7306         /* Found result */
7307         u64 found_offset;
7308 };
7309
7310
7311 /*
7312  * Helper function for find_free_extent().
7313  *
7314  * Return -ENOENT to inform caller that we need fallback to unclustered mode.
7315  * Return -EAGAIN to inform caller that we need to re-search this block group
7316  * Return >0 to inform caller that we find nothing
7317  * Return 0 means we have found a location and set ffe_ctl->found_offset.
7318  */
7319 static int find_free_extent_clustered(struct btrfs_block_group_cache *bg,
7320                 struct btrfs_free_cluster *last_ptr,
7321                 struct find_free_extent_ctl *ffe_ctl,
7322                 struct btrfs_block_group_cache **cluster_bg_ret)
7323 {
7324         struct btrfs_fs_info *fs_info = bg->fs_info;
7325         struct btrfs_block_group_cache *cluster_bg;
7326         u64 aligned_cluster;
7327         u64 offset;
7328         int ret;
7329
7330         cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc);
7331         if (!cluster_bg)
7332                 goto refill_cluster;
7333         if (cluster_bg != bg && (cluster_bg->ro ||
7334             !block_group_bits(cluster_bg, ffe_ctl->flags)))
7335                 goto release_cluster;
7336
7337         offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr,
7338                         ffe_ctl->num_bytes, cluster_bg->key.objectid,
7339                         &ffe_ctl->max_extent_size);
7340         if (offset) {
7341                 /* We have a block, we're done */
7342                 spin_unlock(&last_ptr->refill_lock);
7343                 trace_btrfs_reserve_extent_cluster(cluster_bg,
7344                                 ffe_ctl->search_start, ffe_ctl->num_bytes);
7345                 *cluster_bg_ret = cluster_bg;
7346                 ffe_ctl->found_offset = offset;
7347                 return 0;
7348         }
7349         WARN_ON(last_ptr->block_group != cluster_bg);
7350
7351 release_cluster:
7352         /*
7353          * If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so
7354          * lets just skip it and let the allocator find whatever block it can
7355          * find. If we reach this point, we will have tried the cluster
7356          * allocator plenty of times and not have found anything, so we are
7357          * likely way too fragmented for the clustering stuff to find anything.
7358          *
7359          * However, if the cluster is taken from the current block group,
7360          * release the cluster first, so that we stand a better chance of
7361          * succeeding in the unclustered allocation.
7362          */
7363         if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {
7364                 spin_unlock(&last_ptr->refill_lock);
7365                 btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
7366                 return -ENOENT;
7367         }
7368
7369         /* This cluster didn't work out, free it and start over */
7370         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7371
7372         if (cluster_bg != bg)
7373                 btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
7374
7375 refill_cluster:
7376         if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {
7377                 spin_unlock(&last_ptr->refill_lock);
7378                 return -ENOENT;
7379         }
7380
7381         aligned_cluster = max_t(u64,
7382                         ffe_ctl->empty_cluster + ffe_ctl->empty_size,
7383                         bg->full_stripe_len);
7384         ret = btrfs_find_space_cluster(fs_info, bg, last_ptr,
7385                         ffe_ctl->search_start, ffe_ctl->num_bytes,
7386                         aligned_cluster);
7387         if (ret == 0) {
7388                 /* Now pull our allocation out of this cluster */
7389                 offset = btrfs_alloc_from_cluster(bg, last_ptr,
7390                                 ffe_ctl->num_bytes, ffe_ctl->search_start,
7391                                 &ffe_ctl->max_extent_size);
7392                 if (offset) {
7393                         /* We found one, proceed */
7394                         spin_unlock(&last_ptr->refill_lock);
7395                         trace_btrfs_reserve_extent_cluster(bg,
7396                                         ffe_ctl->search_start,
7397                                         ffe_ctl->num_bytes);
7398                         ffe_ctl->found_offset = offset;
7399                         return 0;
7400                 }
7401         } else if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&
7402                    !ffe_ctl->retry_clustered) {
7403                 spin_unlock(&last_ptr->refill_lock);
7404
7405                 ffe_ctl->retry_clustered = true;
7406                 wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
7407                                 ffe_ctl->empty_cluster + ffe_ctl->empty_size);
7408                 return -EAGAIN;
7409         }
7410         /*
7411          * At this point we either didn't find a cluster or we weren't able to
7412          * allocate a block from our cluster.  Free the cluster we've been
7413          * trying to use, and go to the next block group.
7414          */
7415         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7416         spin_unlock(&last_ptr->refill_lock);
7417         return 1;
7418 }
7419
7420 /*
7421  * Return >0 to inform caller that we find nothing
7422  * Return 0 when we found an free extent and set ffe_ctrl->found_offset
7423  * Return -EAGAIN to inform caller that we need to re-search this block group
7424  */
7425 static int find_free_extent_unclustered(struct btrfs_block_group_cache *bg,
7426                 struct btrfs_free_cluster *last_ptr,
7427                 struct find_free_extent_ctl *ffe_ctl)
7428 {
7429         u64 offset;
7430
7431         /*
7432          * We are doing an unclustered allocation, set the fragmented flag so
7433          * we don't bother trying to setup a cluster again until we get more
7434          * space.
7435          */
7436         if (unlikely(last_ptr)) {
7437                 spin_lock(&last_ptr->lock);
7438                 last_ptr->fragmented = 1;
7439                 spin_unlock(&last_ptr->lock);
7440         }
7441         if (ffe_ctl->cached) {
7442                 struct btrfs_free_space_ctl *free_space_ctl;
7443
7444                 free_space_ctl = bg->free_space_ctl;
7445                 spin_lock(&free_space_ctl->tree_lock);
7446                 if (free_space_ctl->free_space <
7447                     ffe_ctl->num_bytes + ffe_ctl->empty_cluster +
7448                     ffe_ctl->empty_size) {
7449                         ffe_ctl->total_free_space = max_t(u64,
7450                                         ffe_ctl->total_free_space,
7451                                         free_space_ctl->free_space);
7452                         spin_unlock(&free_space_ctl->tree_lock);
7453                         return 1;
7454                 }
7455                 spin_unlock(&free_space_ctl->tree_lock);
7456         }
7457
7458         offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start,
7459                         ffe_ctl->num_bytes, ffe_ctl->empty_size,
7460                         &ffe_ctl->max_extent_size);
7461
7462         /*
7463          * If we didn't find a chunk, and we haven't failed on this block group
7464          * before, and this block group is in the middle of caching and we are
7465          * ok with waiting, then go ahead and wait for progress to be made, and
7466          * set @retry_unclustered to true.
7467          *
7468          * If @retry_unclustered is true then we've already waited on this
7469          * block group once and should move on to the next block group.
7470          */
7471         if (!offset && !ffe_ctl->retry_unclustered && !ffe_ctl->cached &&
7472             ffe_ctl->loop > LOOP_CACHING_NOWAIT) {
7473                 wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
7474                                                 ffe_ctl->empty_size);
7475                 ffe_ctl->retry_unclustered = true;
7476                 return -EAGAIN;
7477         } else if (!offset) {
7478                 return 1;
7479         }
7480         ffe_ctl->found_offset = offset;
7481         return 0;
7482 }
7483
7484 /*
7485  * Return >0 means caller needs to re-search for free extent
7486  * Return 0 means we have the needed free extent.
7487  * Return <0 means we failed to locate any free extent.
7488  */
7489 static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
7490                                         struct btrfs_free_cluster *last_ptr,
7491                                         struct btrfs_key *ins,
7492                                         struct find_free_extent_ctl *ffe_ctl,
7493                                         int full_search, bool use_cluster)
7494 {
7495         struct btrfs_root *root = fs_info->extent_root;
7496         int ret;
7497
7498         if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&
7499             ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)
7500                 ffe_ctl->orig_have_caching_bg = true;
7501
7502         if (!ins->objectid && ffe_ctl->loop >= LOOP_CACHING_WAIT &&
7503             ffe_ctl->have_caching_bg)
7504                 return 1;
7505
7506         if (!ins->objectid && ++(ffe_ctl->index) < BTRFS_NR_RAID_TYPES)
7507                 return 1;
7508
7509         if (ins->objectid) {
7510                 if (!use_cluster && last_ptr) {
7511                         spin_lock(&last_ptr->lock);
7512                         last_ptr->window_start = ins->objectid;
7513                         spin_unlock(&last_ptr->lock);
7514                 }
7515                 return 0;
7516         }
7517
7518         /*
7519          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7520          *                      caching kthreads as we move along
7521          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7522          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7523          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7524          *                     again
7525          */
7526         if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
7527                 ffe_ctl->index = 0;
7528                 if (ffe_ctl->loop == LOOP_CACHING_NOWAIT) {
7529                         /*
7530                          * We want to skip the LOOP_CACHING_WAIT step if we
7531                          * don't have any uncached bgs and we've already done a
7532                          * full search through.
7533                          */
7534                         if (ffe_ctl->orig_have_caching_bg || !full_search)
7535                                 ffe_ctl->loop = LOOP_CACHING_WAIT;
7536                         else
7537                                 ffe_ctl->loop = LOOP_ALLOC_CHUNK;
7538                 } else {
7539                         ffe_ctl->loop++;
7540                 }
7541
7542                 if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {
7543                         struct btrfs_trans_handle *trans;
7544                         int exist = 0;
7545
7546                         trans = current->journal_info;
7547                         if (trans)
7548                                 exist = 1;
7549                         else
7550                                 trans = btrfs_join_transaction(root);
7551
7552                         if (IS_ERR(trans)) {
7553                                 ret = PTR_ERR(trans);
7554                                 return ret;
7555                         }
7556
7557                         ret = do_chunk_alloc(trans, ffe_ctl->flags,
7558                                              CHUNK_ALLOC_FORCE);
7559
7560                         /*
7561                          * If we can't allocate a new chunk we've already looped
7562                          * through at least once, move on to the NO_EMPTY_SIZE
7563                          * case.
7564                          */
7565                         if (ret == -ENOSPC)
7566                                 ffe_ctl->loop = LOOP_NO_EMPTY_SIZE;
7567
7568                         /* Do not bail out on ENOSPC since we can do more. */
7569                         if (ret < 0 && ret != -ENOSPC)
7570                                 btrfs_abort_transaction(trans, ret);
7571                         else
7572                                 ret = 0;
7573                         if (!exist)
7574                                 btrfs_end_transaction(trans);
7575                         if (ret)
7576                                 return ret;
7577                 }
7578
7579                 if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {
7580                         /*
7581                          * Don't loop again if we already have no empty_size and
7582                          * no empty_cluster.
7583                          */
7584                         if (ffe_ctl->empty_size == 0 &&
7585                             ffe_ctl->empty_cluster == 0)
7586                                 return -ENOSPC;
7587                         ffe_ctl->empty_size = 0;
7588                         ffe_ctl->empty_cluster = 0;
7589                 }
7590                 return 1;
7591         }
7592         return -ENOSPC;
7593 }
7594
7595 /*
7596  * walks the btree of allocated extents and find a hole of a given size.
7597  * The key ins is changed to record the hole:
7598  * ins->objectid == start position
7599  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7600  * ins->offset == the size of the hole.
7601  * Any available blocks before search_start are skipped.
7602  *
7603  * If there is no suitable free space, we will record the max size of
7604  * the free space extent currently.
7605  *
7606  * The overall logic and call chain:
7607  *
7608  * find_free_extent()
7609  * |- Iterate through all block groups
7610  * |  |- Get a valid block group
7611  * |  |- Try to do clustered allocation in that block group
7612  * |  |- Try to do unclustered allocation in that block group
7613  * |  |- Check if the result is valid
7614  * |  |  |- If valid, then exit
7615  * |  |- Jump to next block group
7616  * |
7617  * |- Push harder to find free extents
7618  *    |- If not found, re-iterate all block groups
7619  */
7620 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
7621                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7622                                 u64 hint_byte, struct btrfs_key *ins,
7623                                 u64 flags, int delalloc)
7624 {
7625         int ret = 0;
7626         struct btrfs_free_cluster *last_ptr = NULL;
7627         struct btrfs_block_group_cache *block_group = NULL;
7628         struct find_free_extent_ctl ffe_ctl = {0};
7629         struct btrfs_space_info *space_info;
7630         bool use_cluster = true;
7631         bool full_search = false;
7632
7633         WARN_ON(num_bytes < fs_info->sectorsize);
7634
7635         ffe_ctl.ram_bytes = ram_bytes;
7636         ffe_ctl.num_bytes = num_bytes;
7637         ffe_ctl.empty_size = empty_size;
7638         ffe_ctl.flags = flags;
7639         ffe_ctl.search_start = 0;
7640         ffe_ctl.retry_clustered = false;
7641         ffe_ctl.retry_unclustered = false;
7642         ffe_ctl.delalloc = delalloc;
7643         ffe_ctl.index = btrfs_bg_flags_to_raid_index(flags);
7644         ffe_ctl.have_caching_bg = false;
7645         ffe_ctl.orig_have_caching_bg = false;
7646         ffe_ctl.found_offset = 0;
7647
7648         ins->type = BTRFS_EXTENT_ITEM_KEY;
7649         ins->objectid = 0;
7650         ins->offset = 0;
7651
7652         trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
7653
7654         space_info = __find_space_info(fs_info, flags);
7655         if (!space_info) {
7656                 btrfs_err(fs_info, "No space info for %llu", flags);
7657                 return -ENOSPC;
7658         }
7659
7660         /*
7661          * If our free space is heavily fragmented we may not be able to make
7662          * big contiguous allocations, so instead of doing the expensive search
7663          * for free space, simply return ENOSPC with our max_extent_size so we
7664          * can go ahead and search for a more manageable chunk.
7665          *
7666          * If our max_extent_size is large enough for our allocation simply
7667          * disable clustering since we will likely not be able to find enough
7668          * space to create a cluster and induce latency trying.
7669          */
7670         if (unlikely(space_info->max_extent_size)) {
7671                 spin_lock(&space_info->lock);
7672                 if (space_info->max_extent_size &&
7673                     num_bytes > space_info->max_extent_size) {
7674                         ins->offset = space_info->max_extent_size;
7675                         spin_unlock(&space_info->lock);
7676                         return -ENOSPC;
7677                 } else if (space_info->max_extent_size) {
7678                         use_cluster = false;
7679                 }
7680                 spin_unlock(&space_info->lock);
7681         }
7682
7683         last_ptr = fetch_cluster_info(fs_info, space_info,
7684                                       &ffe_ctl.empty_cluster);
7685         if (last_ptr) {
7686                 spin_lock(&last_ptr->lock);
7687                 if (last_ptr->block_group)
7688                         hint_byte = last_ptr->window_start;
7689                 if (last_ptr->fragmented) {
7690                         /*
7691                          * We still set window_start so we can keep track of the
7692                          * last place we found an allocation to try and save
7693                          * some time.
7694                          */
7695                         hint_byte = last_ptr->window_start;
7696                         use_cluster = false;
7697                 }
7698                 spin_unlock(&last_ptr->lock);
7699         }
7700
7701         ffe_ctl.search_start = max(ffe_ctl.search_start,
7702                                    first_logical_byte(fs_info, 0));
7703         ffe_ctl.search_start = max(ffe_ctl.search_start, hint_byte);
7704         if (ffe_ctl.search_start == hint_byte) {
7705                 block_group = btrfs_lookup_block_group(fs_info,
7706                                                        ffe_ctl.search_start);
7707                 /*
7708                  * we don't want to use the block group if it doesn't match our
7709                  * allocation bits, or if its not cached.
7710                  *
7711                  * However if we are re-searching with an ideal block group
7712                  * picked out then we don't care that the block group is cached.
7713                  */
7714                 if (block_group && block_group_bits(block_group, flags) &&
7715                     block_group->cached != BTRFS_CACHE_NO) {
7716                         down_read(&space_info->groups_sem);
7717                         if (list_empty(&block_group->list) ||
7718                             block_group->ro) {
7719                                 /*
7720                                  * someone is removing this block group,
7721                                  * we can't jump into the have_block_group
7722                                  * target because our list pointers are not
7723                                  * valid
7724                                  */
7725                                 btrfs_put_block_group(block_group);
7726                                 up_read(&space_info->groups_sem);
7727                         } else {
7728                                 ffe_ctl.index = btrfs_bg_flags_to_raid_index(
7729                                                 block_group->flags);
7730                                 btrfs_lock_block_group(block_group, delalloc);
7731                                 goto have_block_group;
7732                         }
7733                 } else if (block_group) {
7734                         btrfs_put_block_group(block_group);
7735                 }
7736         }
7737 search:
7738         ffe_ctl.have_caching_bg = false;
7739         if (ffe_ctl.index == btrfs_bg_flags_to_raid_index(flags) ||
7740             ffe_ctl.index == 0)
7741                 full_search = true;
7742         down_read(&space_info->groups_sem);
7743         list_for_each_entry(block_group,
7744                             &space_info->block_groups[ffe_ctl.index], list) {
7745                 /* If the block group is read-only, we can skip it entirely. */
7746                 if (unlikely(block_group->ro))
7747                         continue;
7748
7749                 btrfs_grab_block_group(block_group, delalloc);
7750                 ffe_ctl.search_start = block_group->key.objectid;
7751
7752                 /*
7753                  * this can happen if we end up cycling through all the
7754                  * raid types, but we want to make sure we only allocate
7755                  * for the proper type.
7756                  */
7757                 if (!block_group_bits(block_group, flags)) {
7758                         u64 extra = BTRFS_BLOCK_GROUP_DUP |
7759                                 BTRFS_BLOCK_GROUP_RAID1 |
7760                                 BTRFS_BLOCK_GROUP_RAID5 |
7761                                 BTRFS_BLOCK_GROUP_RAID6 |
7762                                 BTRFS_BLOCK_GROUP_RAID10;
7763
7764                         /*
7765                          * if they asked for extra copies and this block group
7766                          * doesn't provide them, bail.  This does allow us to
7767                          * fill raid0 from raid1.
7768                          */
7769                         if ((flags & extra) && !(block_group->flags & extra))
7770                                 goto loop;
7771                 }
7772
7773 have_block_group:
7774                 ffe_ctl.cached = block_group_cache_done(block_group);
7775                 if (unlikely(!ffe_ctl.cached)) {
7776                         ffe_ctl.have_caching_bg = true;
7777                         ret = cache_block_group(block_group, 0);
7778                         BUG_ON(ret < 0);
7779                         ret = 0;
7780                 }
7781
7782                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7783                         goto loop;
7784
7785                 /*
7786                  * Ok we want to try and use the cluster allocator, so
7787                  * lets look there
7788                  */
7789                 if (last_ptr && use_cluster) {
7790                         struct btrfs_block_group_cache *cluster_bg = NULL;
7791
7792                         ret = find_free_extent_clustered(block_group, last_ptr,
7793                                                          &ffe_ctl, &cluster_bg);
7794
7795                         if (ret == 0) {
7796                                 if (cluster_bg && cluster_bg != block_group) {
7797                                         btrfs_release_block_group(block_group,
7798                                                                   delalloc);
7799                                         block_group = cluster_bg;
7800                                 }
7801                                 goto checks;
7802                         } else if (ret == -EAGAIN) {
7803                                 goto have_block_group;
7804                         } else if (ret > 0) {
7805                                 goto loop;
7806                         }
7807                         /* ret == -ENOENT case falls through */
7808                 }
7809
7810                 ret = find_free_extent_unclustered(block_group, last_ptr,
7811                                                    &ffe_ctl);
7812                 if (ret == -EAGAIN)
7813                         goto have_block_group;
7814                 else if (ret > 0)
7815                         goto loop;
7816                 /* ret == 0 case falls through */
7817 checks:
7818                 ffe_ctl.search_start = round_up(ffe_ctl.found_offset,
7819                                              fs_info->stripesize);
7820
7821                 /* move on to the next group */
7822                 if (ffe_ctl.search_start + num_bytes >
7823                     block_group->key.objectid + block_group->key.offset) {
7824                         btrfs_add_free_space(block_group, ffe_ctl.found_offset,
7825                                              num_bytes);
7826                         goto loop;
7827                 }
7828
7829                 if (ffe_ctl.found_offset < ffe_ctl.search_start)
7830                         btrfs_add_free_space(block_group, ffe_ctl.found_offset,
7831                                 ffe_ctl.search_start - ffe_ctl.found_offset);
7832
7833                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7834                                 num_bytes, delalloc);
7835                 if (ret == -EAGAIN) {
7836                         btrfs_add_free_space(block_group, ffe_ctl.found_offset,
7837                                              num_bytes);
7838                         goto loop;
7839                 }
7840                 btrfs_inc_block_group_reservations(block_group);
7841
7842                 /* we are all good, lets return */
7843                 ins->objectid = ffe_ctl.search_start;
7844                 ins->offset = num_bytes;
7845
7846                 trace_btrfs_reserve_extent(block_group, ffe_ctl.search_start,
7847                                            num_bytes);
7848                 btrfs_release_block_group(block_group, delalloc);
7849                 break;
7850 loop:
7851                 ffe_ctl.retry_clustered = false;
7852                 ffe_ctl.retry_unclustered = false;
7853                 BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
7854                        ffe_ctl.index);
7855                 btrfs_release_block_group(block_group, delalloc);
7856                 cond_resched();
7857         }
7858         up_read(&space_info->groups_sem);
7859
7860         ret = find_free_extent_update_loop(fs_info, last_ptr, ins, &ffe_ctl,
7861                                            full_search, use_cluster);
7862         if (ret > 0)
7863                 goto search;
7864
7865         if (ret == -ENOSPC) {
7866                 /*
7867                  * Use ffe_ctl->total_free_space as fallback if we can't find
7868                  * any contiguous hole.
7869                  */
7870                 if (!ffe_ctl.max_extent_size)
7871                         ffe_ctl.max_extent_size = ffe_ctl.total_free_space;
7872                 spin_lock(&space_info->lock);
7873                 space_info->max_extent_size = ffe_ctl.max_extent_size;
7874                 spin_unlock(&space_info->lock);
7875                 ins->offset = ffe_ctl.max_extent_size;
7876         }
7877         return ret;
7878 }
7879
7880 static void dump_space_info(struct btrfs_fs_info *fs_info,
7881                             struct btrfs_space_info *info, u64 bytes,
7882                             int dump_block_groups)
7883 {
7884         struct btrfs_block_group_cache *cache;
7885         int index = 0;
7886
7887         spin_lock(&info->lock);
7888         btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
7889                    info->flags,
7890                    info->total_bytes - btrfs_space_info_used(info, true),
7891                    info->full ? "" : "not ");
7892         btrfs_info(fs_info,
7893                 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
7894                 info->total_bytes, info->bytes_used, info->bytes_pinned,
7895                 info->bytes_reserved, info->bytes_may_use,
7896                 info->bytes_readonly);
7897         spin_unlock(&info->lock);
7898
7899         if (!dump_block_groups)
7900                 return;
7901
7902         down_read(&info->groups_sem);
7903 again:
7904         list_for_each_entry(cache, &info->block_groups[index], list) {
7905                 spin_lock(&cache->lock);
7906                 btrfs_info(fs_info,
7907                         "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
7908                         cache->key.objectid, cache->key.offset,
7909                         btrfs_block_group_used(&cache->item), cache->pinned,
7910                         cache->reserved, cache->ro ? "[readonly]" : "");
7911                 btrfs_dump_free_space(cache, bytes);
7912                 spin_unlock(&cache->lock);
7913         }
7914         if (++index < BTRFS_NR_RAID_TYPES)
7915                 goto again;
7916         up_read(&info->groups_sem);
7917 }
7918
7919 /*
7920  * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
7921  *                        hole that is at least as big as @num_bytes.
7922  *
7923  * @root           -    The root that will contain this extent
7924  *
7925  * @ram_bytes      -    The amount of space in ram that @num_bytes take. This
7926  *                      is used for accounting purposes. This value differs
7927  *                      from @num_bytes only in the case of compressed extents.
7928  *
7929  * @num_bytes      -    Number of bytes to allocate on-disk.
7930  *
7931  * @min_alloc_size -    Indicates the minimum amount of space that the
7932  *                      allocator should try to satisfy. In some cases
7933  *                      @num_bytes may be larger than what is required and if
7934  *                      the filesystem is fragmented then allocation fails.
7935  *                      However, the presence of @min_alloc_size gives a
7936  *                      chance to try and satisfy the smaller allocation.
7937  *
7938  * @empty_size     -    A hint that you plan on doing more COW. This is the
7939  *                      size in bytes the allocator should try to find free
7940  *                      next to the block it returns.  This is just a hint and
7941  *                      may be ignored by the allocator.
7942  *
7943  * @hint_byte      -    Hint to the allocator to start searching above the byte
7944  *                      address passed. It might be ignored.
7945  *
7946  * @ins            -    This key is modified to record the found hole. It will
7947  *                      have the following values:
7948  *                      ins->objectid == start position
7949  *                      ins->flags = BTRFS_EXTENT_ITEM_KEY
7950  *                      ins->offset == the size of the hole.
7951  *
7952  * @is_data        -    Boolean flag indicating whether an extent is
7953  *                      allocated for data (true) or metadata (false)
7954  *
7955  * @delalloc       -    Boolean flag indicating whether this allocation is for
7956  *                      delalloc or not. If 'true' data_rwsem of block groups
7957  *                      is going to be acquired.
7958  *
7959  *
7960  * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
7961  * case -ENOSPC is returned then @ins->offset will contain the size of the
7962  * largest available hole the allocator managed to find.
7963  */
7964 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
7965                          u64 num_bytes, u64 min_alloc_size,
7966                          u64 empty_size, u64 hint_byte,
7967                          struct btrfs_key *ins, int is_data, int delalloc)
7968 {
7969         struct btrfs_fs_info *fs_info = root->fs_info;
7970         bool final_tried = num_bytes == min_alloc_size;
7971         u64 flags;
7972         int ret;
7973
7974         flags = get_alloc_profile_by_root(root, is_data);
7975 again:
7976         WARN_ON(num_bytes < fs_info->sectorsize);
7977         ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
7978                                hint_byte, ins, flags, delalloc);
7979         if (!ret && !is_data) {
7980                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
7981         } else if (ret == -ENOSPC) {
7982                 if (!final_tried && ins->offset) {
7983                         num_bytes = min(num_bytes >> 1, ins->offset);
7984                         num_bytes = round_down(num_bytes,
7985                                                fs_info->sectorsize);
7986                         num_bytes = max(num_bytes, min_alloc_size);
7987                         ram_bytes = num_bytes;
7988                         if (num_bytes == min_alloc_size)
7989                                 final_tried = true;
7990                         goto again;
7991                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
7992                         struct btrfs_space_info *sinfo;
7993
7994                         sinfo = __find_space_info(fs_info, flags);
7995                         btrfs_err(fs_info,
7996                                   "allocation failed flags %llu, wanted %llu",
7997                                   flags, num_bytes);
7998                         if (sinfo)
7999                                 dump_space_info(fs_info, sinfo, num_bytes, 1);
8000                 }
8001         }
8002
8003         return ret;
8004 }
8005
8006 static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8007                                         u64 start, u64 len,
8008                                         int pin, int delalloc)
8009 {
8010         struct btrfs_block_group_cache *cache;
8011         int ret = 0;
8012
8013         cache = btrfs_lookup_block_group(fs_info, start);
8014         if (!cache) {
8015                 btrfs_err(fs_info, "Unable to find block group for %llu",
8016                           start);
8017                 return -ENOSPC;
8018         }
8019
8020         if (pin)
8021                 pin_down_extent(fs_info, cache, start, len, 1);
8022         else {
8023                 if (btrfs_test_opt(fs_info, DISCARD))
8024                         ret = btrfs_discard_extent(fs_info, start, len, NULL);
8025                 btrfs_add_free_space(cache, start, len);
8026                 btrfs_free_reserved_bytes(cache, len, delalloc);
8027                 trace_btrfs_reserved_extent_free(fs_info, start, len);
8028         }
8029
8030         btrfs_put_block_group(cache);
8031         return ret;
8032 }
8033
8034 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8035                                u64 start, u64 len, int delalloc)
8036 {
8037         return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
8038 }
8039
8040 int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
8041                                        u64 start, u64 len)
8042 {
8043         return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
8044 }
8045
8046 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8047                                       u64 parent, u64 root_objectid,
8048                                       u64 flags, u64 owner, u64 offset,
8049                                       struct btrfs_key *ins, int ref_mod)
8050 {
8051         struct btrfs_fs_info *fs_info = trans->fs_info;
8052         int ret;
8053         struct btrfs_extent_item *extent_item;
8054         struct btrfs_extent_inline_ref *iref;
8055         struct btrfs_path *path;
8056         struct extent_buffer *leaf;
8057         int type;
8058         u32 size;
8059
8060         if (parent > 0)
8061                 type = BTRFS_SHARED_DATA_REF_KEY;
8062         else
8063                 type = BTRFS_EXTENT_DATA_REF_KEY;
8064
8065         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8066
8067         path = btrfs_alloc_path();
8068         if (!path)
8069                 return -ENOMEM;
8070
8071         path->leave_spinning = 1;
8072         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8073                                       ins, size);
8074         if (ret) {
8075                 btrfs_free_path(path);
8076                 return ret;
8077         }
8078
8079         leaf = path->nodes[0];
8080         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8081                                      struct btrfs_extent_item);
8082         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8083         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8084         btrfs_set_extent_flags(leaf, extent_item,
8085                                flags | BTRFS_EXTENT_FLAG_DATA);
8086
8087         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8088         btrfs_set_extent_inline_ref_type(leaf, iref, type);
8089         if (parent > 0) {
8090                 struct btrfs_shared_data_ref *ref;
8091                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8092                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8093                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8094         } else {
8095                 struct btrfs_extent_data_ref *ref;
8096                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8097                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8098                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8099                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8100                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8101         }
8102
8103         btrfs_mark_buffer_dirty(path->nodes[0]);
8104         btrfs_free_path(path);
8105
8106         ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset);
8107         if (ret)
8108                 return ret;
8109
8110         ret = update_block_group(trans, fs_info, ins->objectid, ins->offset, 1);
8111         if (ret) { /* -ENOENT, logic error */
8112                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8113                         ins->objectid, ins->offset);
8114                 BUG();
8115         }
8116         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
8117         return ret;
8118 }
8119
8120 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8121                                      struct btrfs_delayed_ref_node *node,
8122                                      struct btrfs_delayed_extent_op *extent_op)
8123 {
8124         struct btrfs_fs_info *fs_info = trans->fs_info;
8125         int ret;
8126         struct btrfs_extent_item *extent_item;
8127         struct btrfs_key extent_key;
8128         struct btrfs_tree_block_info *block_info;
8129         struct btrfs_extent_inline_ref *iref;
8130         struct btrfs_path *path;
8131         struct extent_buffer *leaf;
8132         struct btrfs_delayed_tree_ref *ref;
8133         u32 size = sizeof(*extent_item) + sizeof(*iref);
8134         u64 num_bytes;
8135         u64 flags = extent_op->flags_to_set;
8136         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8137
8138         ref = btrfs_delayed_node_to_tree_ref(node);
8139
8140         extent_key.objectid = node->bytenr;
8141         if (skinny_metadata) {
8142                 extent_key.offset = ref->level;
8143                 extent_key.type = BTRFS_METADATA_ITEM_KEY;
8144                 num_bytes = fs_info->nodesize;
8145         } else {
8146                 extent_key.offset = node->num_bytes;
8147                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
8148                 size += sizeof(*block_info);
8149                 num_bytes = node->num_bytes;
8150         }
8151
8152         path = btrfs_alloc_path();
8153         if (!path)
8154                 return -ENOMEM;
8155
8156         path->leave_spinning = 1;
8157         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8158                                       &extent_key, size);
8159         if (ret) {
8160                 btrfs_free_path(path);
8161                 return ret;
8162         }
8163
8164         leaf = path->nodes[0];
8165         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8166                                      struct btrfs_extent_item);
8167         btrfs_set_extent_refs(leaf, extent_item, 1);
8168         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8169         btrfs_set_extent_flags(leaf, extent_item,
8170                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8171
8172         if (skinny_metadata) {
8173                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8174         } else {
8175                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8176                 btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
8177                 btrfs_set_tree_block_level(leaf, block_info, ref->level);
8178                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8179         }
8180
8181         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
8182                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8183                 btrfs_set_extent_inline_ref_type(leaf, iref,
8184                                                  BTRFS_SHARED_BLOCK_REF_KEY);
8185                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
8186         } else {
8187                 btrfs_set_extent_inline_ref_type(leaf, iref,
8188                                                  BTRFS_TREE_BLOCK_REF_KEY);
8189                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
8190         }
8191
8192         btrfs_mark_buffer_dirty(leaf);
8193         btrfs_free_path(path);
8194
8195         ret = remove_from_free_space_tree(trans, extent_key.objectid,
8196                                           num_bytes);
8197         if (ret)
8198                 return ret;
8199
8200         ret = update_block_group(trans, fs_info, extent_key.objectid,
8201                                  fs_info->nodesize, 1);
8202         if (ret) { /* -ENOENT, logic error */
8203                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8204                         extent_key.objectid, extent_key.offset);
8205                 BUG();
8206         }
8207
8208         trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid,
8209                                           fs_info->nodesize);
8210         return ret;
8211 }
8212
8213 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8214                                      struct btrfs_root *root, u64 owner,
8215                                      u64 offset, u64 ram_bytes,
8216                                      struct btrfs_key *ins)
8217 {
8218         int ret;
8219
8220         BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
8221
8222         btrfs_ref_tree_mod(root, ins->objectid, ins->offset, 0,
8223                            root->root_key.objectid, owner, offset,
8224                            BTRFS_ADD_DELAYED_EXTENT);
8225
8226         ret = btrfs_add_delayed_data_ref(trans, ins->objectid,
8227                                          ins->offset, 0,
8228                                          root->root_key.objectid, owner,
8229                                          offset, ram_bytes,
8230                                          BTRFS_ADD_DELAYED_EXTENT, NULL, NULL);
8231         return ret;
8232 }
8233
8234 /*
8235  * this is used by the tree logging recovery code.  It records that
8236  * an extent has been allocated and makes sure to clear the free
8237  * space cache bits as well
8238  */
8239 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8240                                    u64 root_objectid, u64 owner, u64 offset,
8241                                    struct btrfs_key *ins)
8242 {
8243         struct btrfs_fs_info *fs_info = trans->fs_info;
8244         int ret;
8245         struct btrfs_block_group_cache *block_group;
8246         struct btrfs_space_info *space_info;
8247
8248         /*
8249          * Mixed block groups will exclude before processing the log so we only
8250          * need to do the exclude dance if this fs isn't mixed.
8251          */
8252         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
8253                 ret = __exclude_logged_extent(fs_info, ins->objectid,
8254                                               ins->offset);
8255                 if (ret)
8256                         return ret;
8257         }
8258
8259         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
8260         if (!block_group)
8261                 return -EINVAL;
8262
8263         space_info = block_group->space_info;
8264         spin_lock(&space_info->lock);
8265         spin_lock(&block_group->lock);
8266         space_info->bytes_reserved += ins->offset;
8267         block_group->reserved += ins->offset;
8268         spin_unlock(&block_group->lock);
8269         spin_unlock(&space_info->lock);
8270
8271         ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
8272                                          offset, ins, 1);
8273         btrfs_put_block_group(block_group);
8274         return ret;
8275 }
8276
8277 static struct extent_buffer *
8278 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8279                       u64 bytenr, int level, u64 owner)
8280 {
8281         struct btrfs_fs_info *fs_info = root->fs_info;
8282         struct extent_buffer *buf;
8283
8284         buf = btrfs_find_create_tree_block(fs_info, bytenr);
8285         if (IS_ERR(buf))
8286                 return buf;
8287
8288         /*
8289          * Extra safety check in case the extent tree is corrupted and extent
8290          * allocator chooses to use a tree block which is already used and
8291          * locked.
8292          */
8293         if (buf->lock_owner == current->pid) {
8294                 btrfs_err_rl(fs_info,
8295 "tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
8296                         buf->start, btrfs_header_owner(buf), current->pid);
8297                 free_extent_buffer(buf);
8298                 return ERR_PTR(-EUCLEAN);
8299         }
8300
8301         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8302         btrfs_tree_lock(buf);
8303         clean_tree_block(fs_info, buf);
8304         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8305
8306         btrfs_set_lock_blocking(buf);
8307         set_extent_buffer_uptodate(buf);
8308
8309         memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
8310         btrfs_set_header_level(buf, level);
8311         btrfs_set_header_bytenr(buf, buf->start);
8312         btrfs_set_header_generation(buf, trans->transid);
8313         btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
8314         btrfs_set_header_owner(buf, owner);
8315         write_extent_buffer_fsid(buf, fs_info->fsid);
8316         write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
8317         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8318                 buf->log_index = root->log_transid % 2;
8319                 /*
8320                  * we allow two log transactions at a time, use different
8321                  * EXENT bit to differentiate dirty pages.
8322                  */
8323                 if (buf->log_index == 0)
8324                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8325                                         buf->start + buf->len - 1, GFP_NOFS);
8326                 else
8327                         set_extent_new(&root->dirty_log_pages, buf->start,
8328                                         buf->start + buf->len - 1);
8329         } else {
8330                 buf->log_index = -1;
8331                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8332                          buf->start + buf->len - 1, GFP_NOFS);
8333         }
8334         trans->dirty = true;
8335         /* this returns a buffer locked for blocking */
8336         return buf;
8337 }
8338
8339 static struct btrfs_block_rsv *
8340 use_block_rsv(struct btrfs_trans_handle *trans,
8341               struct btrfs_root *root, u32 blocksize)
8342 {
8343         struct btrfs_fs_info *fs_info = root->fs_info;
8344         struct btrfs_block_rsv *block_rsv;
8345         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
8346         int ret;
8347         bool global_updated = false;
8348
8349         block_rsv = get_block_rsv(trans, root);
8350
8351         if (unlikely(block_rsv->size == 0))
8352                 goto try_reserve;
8353 again:
8354         ret = block_rsv_use_bytes(block_rsv, blocksize);
8355         if (!ret)
8356                 return block_rsv;
8357
8358         if (block_rsv->failfast)
8359                 return ERR_PTR(ret);
8360
8361         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8362                 global_updated = true;
8363                 update_global_block_rsv(fs_info);
8364                 goto again;
8365         }
8366
8367         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8368                 static DEFINE_RATELIMIT_STATE(_rs,
8369                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8370                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8371                 if (__ratelimit(&_rs))
8372                         WARN(1, KERN_DEBUG
8373                                 "BTRFS: block rsv returned %d\n", ret);
8374         }
8375 try_reserve:
8376         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8377                                      BTRFS_RESERVE_NO_FLUSH);
8378         if (!ret)
8379                 return block_rsv;
8380         /*
8381          * If we couldn't reserve metadata bytes try and use some from
8382          * the global reserve if its space type is the same as the global
8383          * reservation.
8384          */
8385         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8386             block_rsv->space_info == global_rsv->space_info) {
8387                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8388                 if (!ret)
8389                         return global_rsv;
8390         }
8391         return ERR_PTR(ret);
8392 }
8393
8394 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8395                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8396 {
8397         block_rsv_add_bytes(block_rsv, blocksize, false);
8398         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0, NULL);
8399 }
8400
8401 /*
8402  * finds a free extent and does all the dirty work required for allocation
8403  * returns the tree buffer or an ERR_PTR on error.
8404  */
8405 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8406                                              struct btrfs_root *root,
8407                                              u64 parent, u64 root_objectid,
8408                                              const struct btrfs_disk_key *key,
8409                                              int level, u64 hint,
8410                                              u64 empty_size)
8411 {
8412         struct btrfs_fs_info *fs_info = root->fs_info;
8413         struct btrfs_key ins;
8414         struct btrfs_block_rsv *block_rsv;
8415         struct extent_buffer *buf;
8416         struct btrfs_delayed_extent_op *extent_op;
8417         u64 flags = 0;
8418         int ret;
8419         u32 blocksize = fs_info->nodesize;
8420         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8421
8422 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8423         if (btrfs_is_testing(fs_info)) {
8424                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8425                                             level, root_objectid);
8426                 if (!IS_ERR(buf))
8427                         root->alloc_bytenr += blocksize;
8428                 return buf;
8429         }
8430 #endif
8431
8432         block_rsv = use_block_rsv(trans, root, blocksize);
8433         if (IS_ERR(block_rsv))
8434                 return ERR_CAST(block_rsv);
8435
8436         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8437                                    empty_size, hint, &ins, 0, 0);
8438         if (ret)
8439                 goto out_unuse;
8440
8441         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
8442                                     root_objectid);
8443         if (IS_ERR(buf)) {
8444                 ret = PTR_ERR(buf);
8445                 goto out_free_reserved;
8446         }
8447
8448         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8449                 if (parent == 0)
8450                         parent = ins.objectid;
8451                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8452         } else
8453                 BUG_ON(parent > 0);
8454
8455         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8456                 extent_op = btrfs_alloc_delayed_extent_op();
8457                 if (!extent_op) {
8458                         ret = -ENOMEM;
8459                         goto out_free_buf;
8460                 }
8461                 if (key)
8462                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8463                 else
8464                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8465                 extent_op->flags_to_set = flags;
8466                 extent_op->update_key = skinny_metadata ? false : true;
8467                 extent_op->update_flags = true;
8468                 extent_op->is_data = false;
8469                 extent_op->level = level;
8470
8471                 btrfs_ref_tree_mod(root, ins.objectid, ins.offset, parent,
8472                                    root_objectid, level, 0,
8473                                    BTRFS_ADD_DELAYED_EXTENT);
8474                 ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
8475                                                  ins.offset, parent,
8476                                                  root_objectid, level,
8477                                                  BTRFS_ADD_DELAYED_EXTENT,
8478                                                  extent_op, NULL, NULL);
8479                 if (ret)
8480                         goto out_free_delayed;
8481         }
8482         return buf;
8483
8484 out_free_delayed:
8485         btrfs_free_delayed_extent_op(extent_op);
8486 out_free_buf:
8487         free_extent_buffer(buf);
8488 out_free_reserved:
8489         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
8490 out_unuse:
8491         unuse_block_rsv(fs_info, block_rsv, blocksize);
8492         return ERR_PTR(ret);
8493 }
8494
8495 struct walk_control {
8496         u64 refs[BTRFS_MAX_LEVEL];
8497         u64 flags[BTRFS_MAX_LEVEL];
8498         struct btrfs_key update_progress;
8499         int stage;
8500         int level;
8501         int shared_level;
8502         int update_ref;
8503         int keep_locks;
8504         int reada_slot;
8505         int reada_count;
8506 };
8507
8508 #define DROP_REFERENCE  1
8509 #define UPDATE_BACKREF  2
8510
8511 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8512                                      struct btrfs_root *root,
8513                                      struct walk_control *wc,
8514                                      struct btrfs_path *path)
8515 {
8516         struct btrfs_fs_info *fs_info = root->fs_info;
8517         u64 bytenr;
8518         u64 generation;
8519         u64 refs;
8520         u64 flags;
8521         u32 nritems;
8522         struct btrfs_key key;
8523         struct extent_buffer *eb;
8524         int ret;
8525         int slot;
8526         int nread = 0;
8527
8528         if (path->slots[wc->level] < wc->reada_slot) {
8529                 wc->reada_count = wc->reada_count * 2 / 3;
8530                 wc->reada_count = max(wc->reada_count, 2);
8531         } else {
8532                 wc->reada_count = wc->reada_count * 3 / 2;
8533                 wc->reada_count = min_t(int, wc->reada_count,
8534                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
8535         }
8536
8537         eb = path->nodes[wc->level];
8538         nritems = btrfs_header_nritems(eb);
8539
8540         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8541                 if (nread >= wc->reada_count)
8542                         break;
8543
8544                 cond_resched();
8545                 bytenr = btrfs_node_blockptr(eb, slot);
8546                 generation = btrfs_node_ptr_generation(eb, slot);
8547
8548                 if (slot == path->slots[wc->level])
8549                         goto reada;
8550
8551                 if (wc->stage == UPDATE_BACKREF &&
8552                     generation <= root->root_key.offset)
8553                         continue;
8554
8555                 /* We don't lock the tree block, it's OK to be racy here */
8556                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
8557                                                wc->level - 1, 1, &refs,
8558                                                &flags);
8559                 /* We don't care about errors in readahead. */
8560                 if (ret < 0)
8561                         continue;
8562                 BUG_ON(refs == 0);
8563
8564                 if (wc->stage == DROP_REFERENCE) {
8565                         if (refs == 1)
8566                                 goto reada;
8567
8568                         if (wc->level == 1 &&
8569                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8570                                 continue;
8571                         if (!wc->update_ref ||
8572                             generation <= root->root_key.offset)
8573                                 continue;
8574                         btrfs_node_key_to_cpu(eb, &key, slot);
8575                         ret = btrfs_comp_cpu_keys(&key,
8576                                                   &wc->update_progress);
8577                         if (ret < 0)
8578                                 continue;
8579                 } else {
8580                         if (wc->level == 1 &&
8581                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8582                                 continue;
8583                 }
8584 reada:
8585                 readahead_tree_block(fs_info, bytenr);
8586                 nread++;
8587         }
8588         wc->reada_slot = slot;
8589 }
8590
8591 /*
8592  * helper to process tree block while walking down the tree.
8593  *
8594  * when wc->stage == UPDATE_BACKREF, this function updates
8595  * back refs for pointers in the block.
8596  *
8597  * NOTE: return value 1 means we should stop walking down.
8598  */
8599 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8600                                    struct btrfs_root *root,
8601                                    struct btrfs_path *path,
8602                                    struct walk_control *wc, int lookup_info)
8603 {
8604         struct btrfs_fs_info *fs_info = root->fs_info;
8605         int level = wc->level;
8606         struct extent_buffer *eb = path->nodes[level];
8607         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8608         int ret;
8609
8610         if (wc->stage == UPDATE_BACKREF &&
8611             btrfs_header_owner(eb) != root->root_key.objectid)
8612                 return 1;
8613
8614         /*
8615          * when reference count of tree block is 1, it won't increase
8616          * again. once full backref flag is set, we never clear it.
8617          */
8618         if (lookup_info &&
8619             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8620              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8621                 BUG_ON(!path->locks[level]);
8622                 ret = btrfs_lookup_extent_info(trans, fs_info,
8623                                                eb->start, level, 1,
8624                                                &wc->refs[level],
8625                                                &wc->flags[level]);
8626                 BUG_ON(ret == -ENOMEM);
8627                 if (ret)
8628                         return ret;
8629                 BUG_ON(wc->refs[level] == 0);
8630         }
8631
8632         if (wc->stage == DROP_REFERENCE) {
8633                 if (wc->refs[level] > 1)
8634                         return 1;
8635
8636                 if (path->locks[level] && !wc->keep_locks) {
8637                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8638                         path->locks[level] = 0;
8639                 }
8640                 return 0;
8641         }
8642
8643         /* wc->stage == UPDATE_BACKREF */
8644         if (!(wc->flags[level] & flag)) {
8645                 BUG_ON(!path->locks[level]);
8646                 ret = btrfs_inc_ref(trans, root, eb, 1);
8647                 BUG_ON(ret); /* -ENOMEM */
8648                 ret = btrfs_dec_ref(trans, root, eb, 0);
8649                 BUG_ON(ret); /* -ENOMEM */
8650                 ret = btrfs_set_disk_extent_flags(trans, fs_info, eb->start,
8651                                                   eb->len, flag,
8652                                                   btrfs_header_level(eb), 0);
8653                 BUG_ON(ret); /* -ENOMEM */
8654                 wc->flags[level] |= flag;
8655         }
8656
8657         /*
8658          * the block is shared by multiple trees, so it's not good to
8659          * keep the tree lock
8660          */
8661         if (path->locks[level] && level > 0) {
8662                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8663                 path->locks[level] = 0;
8664         }
8665         return 0;
8666 }
8667
8668 /*
8669  * helper to process tree block pointer.
8670  *
8671  * when wc->stage == DROP_REFERENCE, this function checks
8672  * reference count of the block pointed to. if the block
8673  * is shared and we need update back refs for the subtree
8674  * rooted at the block, this function changes wc->stage to
8675  * UPDATE_BACKREF. if the block is shared and there is no
8676  * need to update back, this function drops the reference
8677  * to the block.
8678  *
8679  * NOTE: return value 1 means we should stop walking down.
8680  */
8681 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8682                                  struct btrfs_root *root,
8683                                  struct btrfs_path *path,
8684                                  struct walk_control *wc, int *lookup_info)
8685 {
8686         struct btrfs_fs_info *fs_info = root->fs_info;
8687         u64 bytenr;
8688         u64 generation;
8689         u64 parent;
8690         u32 blocksize;
8691         struct btrfs_key key;
8692         struct btrfs_key first_key;
8693         struct extent_buffer *next;
8694         int level = wc->level;
8695         int reada = 0;
8696         int ret = 0;
8697         bool need_account = false;
8698
8699         generation = btrfs_node_ptr_generation(path->nodes[level],
8700                                                path->slots[level]);
8701         /*
8702          * if the lower level block was created before the snapshot
8703          * was created, we know there is no need to update back refs
8704          * for the subtree
8705          */
8706         if (wc->stage == UPDATE_BACKREF &&
8707             generation <= root->root_key.offset) {
8708                 *lookup_info = 1;
8709                 return 1;
8710         }
8711
8712         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8713         btrfs_node_key_to_cpu(path->nodes[level], &first_key,
8714                               path->slots[level]);
8715         blocksize = fs_info->nodesize;
8716
8717         next = find_extent_buffer(fs_info, bytenr);
8718         if (!next) {
8719                 next = btrfs_find_create_tree_block(fs_info, bytenr);
8720                 if (IS_ERR(next))
8721                         return PTR_ERR(next);
8722
8723                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8724                                                level - 1);
8725                 reada = 1;
8726         }
8727         btrfs_tree_lock(next);
8728         btrfs_set_lock_blocking(next);
8729
8730         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
8731                                        &wc->refs[level - 1],
8732                                        &wc->flags[level - 1]);
8733         if (ret < 0)
8734                 goto out_unlock;
8735
8736         if (unlikely(wc->refs[level - 1] == 0)) {
8737                 btrfs_err(fs_info, "Missing references.");
8738                 ret = -EIO;
8739                 goto out_unlock;
8740         }
8741         *lookup_info = 0;
8742
8743         if (wc->stage == DROP_REFERENCE) {
8744                 if (wc->refs[level - 1] > 1) {
8745                         need_account = true;
8746                         if (level == 1 &&
8747                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8748                                 goto skip;
8749
8750                         if (!wc->update_ref ||
8751                             generation <= root->root_key.offset)
8752                                 goto skip;
8753
8754                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8755                                               path->slots[level]);
8756                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8757                         if (ret < 0)
8758                                 goto skip;
8759
8760                         wc->stage = UPDATE_BACKREF;
8761                         wc->shared_level = level - 1;
8762                 }
8763         } else {
8764                 if (level == 1 &&
8765                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8766                         goto skip;
8767         }
8768
8769         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8770                 btrfs_tree_unlock(next);
8771                 free_extent_buffer(next);
8772                 next = NULL;
8773                 *lookup_info = 1;
8774         }
8775
8776         if (!next) {
8777                 if (reada && level == 1)
8778                         reada_walk_down(trans, root, wc, path);
8779                 next = read_tree_block(fs_info, bytenr, generation, level - 1,
8780                                        &first_key);
8781                 if (IS_ERR(next)) {
8782                         return PTR_ERR(next);
8783                 } else if (!extent_buffer_uptodate(next)) {
8784                         free_extent_buffer(next);
8785                         return -EIO;
8786                 }
8787                 btrfs_tree_lock(next);
8788                 btrfs_set_lock_blocking(next);
8789         }
8790
8791         level--;
8792         ASSERT(level == btrfs_header_level(next));
8793         if (level != btrfs_header_level(next)) {
8794                 btrfs_err(root->fs_info, "mismatched level");
8795                 ret = -EIO;
8796                 goto out_unlock;
8797         }
8798         path->nodes[level] = next;
8799         path->slots[level] = 0;
8800         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8801         wc->level = level;
8802         if (wc->level == 1)
8803                 wc->reada_slot = 0;
8804         return 0;
8805 skip:
8806         wc->refs[level - 1] = 0;
8807         wc->flags[level - 1] = 0;
8808         if (wc->stage == DROP_REFERENCE) {
8809                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8810                         parent = path->nodes[level]->start;
8811                 } else {
8812                         ASSERT(root->root_key.objectid ==
8813                                btrfs_header_owner(path->nodes[level]));
8814                         if (root->root_key.objectid !=
8815                             btrfs_header_owner(path->nodes[level])) {
8816                                 btrfs_err(root->fs_info,
8817                                                 "mismatched block owner");
8818                                 ret = -EIO;
8819                                 goto out_unlock;
8820                         }
8821                         parent = 0;
8822                 }
8823
8824                 /*
8825                  * Reloc tree doesn't contribute to qgroup numbers, and we have
8826                  * already accounted them at merge time (replace_path),
8827                  * thus we could skip expensive subtree trace here.
8828                  */
8829                 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
8830                     need_account) {
8831                         ret = btrfs_qgroup_trace_subtree(trans, next,
8832                                                          generation, level - 1);
8833                         if (ret) {
8834                                 btrfs_err_rl(fs_info,
8835                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8836                                              ret);
8837                         }
8838                 }
8839                 ret = btrfs_free_extent(trans, root, bytenr, blocksize,
8840                                         parent, root->root_key.objectid,
8841                                         level - 1, 0);
8842                 if (ret)
8843                         goto out_unlock;
8844         }
8845
8846         *lookup_info = 1;
8847         ret = 1;
8848
8849 out_unlock:
8850         btrfs_tree_unlock(next);
8851         free_extent_buffer(next);
8852
8853         return ret;
8854 }
8855
8856 /*
8857  * helper to process tree block while walking up the tree.
8858  *
8859  * when wc->stage == DROP_REFERENCE, this function drops
8860  * reference count on the block.
8861  *
8862  * when wc->stage == UPDATE_BACKREF, this function changes
8863  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8864  * to UPDATE_BACKREF previously while processing the block.
8865  *
8866  * NOTE: return value 1 means we should stop walking up.
8867  */
8868 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8869                                  struct btrfs_root *root,
8870                                  struct btrfs_path *path,
8871                                  struct walk_control *wc)
8872 {
8873         struct btrfs_fs_info *fs_info = root->fs_info;
8874         int ret;
8875         int level = wc->level;
8876         struct extent_buffer *eb = path->nodes[level];
8877         u64 parent = 0;
8878
8879         if (wc->stage == UPDATE_BACKREF) {
8880                 BUG_ON(wc->shared_level < level);
8881                 if (level < wc->shared_level)
8882                         goto out;
8883
8884                 ret = find_next_key(path, level + 1, &wc->update_progress);
8885                 if (ret > 0)
8886                         wc->update_ref = 0;
8887
8888                 wc->stage = DROP_REFERENCE;
8889                 wc->shared_level = -1;
8890                 path->slots[level] = 0;
8891
8892                 /*
8893                  * check reference count again if the block isn't locked.
8894                  * we should start walking down the tree again if reference
8895                  * count is one.
8896                  */
8897                 if (!path->locks[level]) {
8898                         BUG_ON(level == 0);
8899                         btrfs_tree_lock(eb);
8900                         btrfs_set_lock_blocking(eb);
8901                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8902
8903                         ret = btrfs_lookup_extent_info(trans, fs_info,
8904                                                        eb->start, level, 1,
8905                                                        &wc->refs[level],
8906                                                        &wc->flags[level]);
8907                         if (ret < 0) {
8908                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8909                                 path->locks[level] = 0;
8910                                 return ret;
8911                         }
8912                         BUG_ON(wc->refs[level] == 0);
8913                         if (wc->refs[level] == 1) {
8914                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8915                                 path->locks[level] = 0;
8916                                 return 1;
8917                         }
8918                 }
8919         }
8920
8921         /* wc->stage == DROP_REFERENCE */
8922         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8923
8924         if (wc->refs[level] == 1) {
8925                 if (level == 0) {
8926                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8927                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8928                         else
8929                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8930                         BUG_ON(ret); /* -ENOMEM */
8931                         ret = btrfs_qgroup_trace_leaf_items(trans, eb);
8932                         if (ret) {
8933                                 btrfs_err_rl(fs_info,
8934                                              "error %d accounting leaf items. Quota is out of sync, rescan required.",
8935                                              ret);
8936                         }
8937                 }
8938                 /* make block locked assertion in clean_tree_block happy */
8939                 if (!path->locks[level] &&
8940                     btrfs_header_generation(eb) == trans->transid) {
8941                         btrfs_tree_lock(eb);
8942                         btrfs_set_lock_blocking(eb);
8943                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8944                 }
8945                 clean_tree_block(fs_info, eb);
8946         }
8947
8948         if (eb == root->node) {
8949                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8950                         parent = eb->start;
8951                 else if (root->root_key.objectid != btrfs_header_owner(eb))
8952                         goto owner_mismatch;
8953         } else {
8954                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8955                         parent = path->nodes[level + 1]->start;
8956                 else if (root->root_key.objectid !=
8957                          btrfs_header_owner(path->nodes[level + 1]))
8958                         goto owner_mismatch;
8959         }
8960
8961         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8962 out:
8963         wc->refs[level] = 0;
8964         wc->flags[level] = 0;
8965         return 0;
8966
8967 owner_mismatch:
8968         btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
8969                      btrfs_header_owner(eb), root->root_key.objectid);
8970         return -EUCLEAN;
8971 }
8972
8973 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8974                                    struct btrfs_root *root,
8975                                    struct btrfs_path *path,
8976                                    struct walk_control *wc)
8977 {
8978         int level = wc->level;
8979         int lookup_info = 1;
8980         int ret;
8981
8982         while (level >= 0) {
8983                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8984                 if (ret > 0)
8985                         break;
8986
8987                 if (level == 0)
8988                         break;
8989
8990                 if (path->slots[level] >=
8991                     btrfs_header_nritems(path->nodes[level]))
8992                         break;
8993
8994                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8995                 if (ret > 0) {
8996                         path->slots[level]++;
8997                         continue;
8998                 } else if (ret < 0)
8999                         return ret;
9000                 level = wc->level;
9001         }
9002         return 0;
9003 }
9004
9005 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
9006                                  struct btrfs_root *root,
9007                                  struct btrfs_path *path,
9008                                  struct walk_control *wc, int max_level)
9009 {
9010         int level = wc->level;
9011         int ret;
9012
9013         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
9014         while (level < max_level && path->nodes[level]) {
9015                 wc->level = level;
9016                 if (path->slots[level] + 1 <
9017                     btrfs_header_nritems(path->nodes[level])) {
9018                         path->slots[level]++;
9019                         return 0;
9020                 } else {
9021                         ret = walk_up_proc(trans, root, path, wc);
9022                         if (ret > 0)
9023                                 return 0;
9024                         if (ret < 0)
9025                                 return ret;
9026
9027                         if (path->locks[level]) {
9028                                 btrfs_tree_unlock_rw(path->nodes[level],
9029                                                      path->locks[level]);
9030                                 path->locks[level] = 0;
9031                         }
9032                         free_extent_buffer(path->nodes[level]);
9033                         path->nodes[level] = NULL;
9034                         level++;
9035                 }
9036         }
9037         return 1;
9038 }
9039
9040 /*
9041  * drop a subvolume tree.
9042  *
9043  * this function traverses the tree freeing any blocks that only
9044  * referenced by the tree.
9045  *
9046  * when a shared tree block is found. this function decreases its
9047  * reference count by one. if update_ref is true, this function
9048  * also make sure backrefs for the shared block and all lower level
9049  * blocks are properly updated.
9050  *
9051  * If called with for_reloc == 0, may exit early with -EAGAIN
9052  */
9053 int btrfs_drop_snapshot(struct btrfs_root *root,
9054                          struct btrfs_block_rsv *block_rsv, int update_ref,
9055                          int for_reloc)
9056 {
9057         struct btrfs_fs_info *fs_info = root->fs_info;
9058         struct btrfs_path *path;
9059         struct btrfs_trans_handle *trans;
9060         struct btrfs_root *tree_root = fs_info->tree_root;
9061         struct btrfs_root_item *root_item = &root->root_item;
9062         struct walk_control *wc;
9063         struct btrfs_key key;
9064         int err = 0;
9065         int ret;
9066         int level;
9067         bool root_dropped = false;
9068
9069         btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
9070
9071         path = btrfs_alloc_path();
9072         if (!path) {
9073                 err = -ENOMEM;
9074                 goto out;
9075         }
9076
9077         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9078         if (!wc) {
9079                 btrfs_free_path(path);
9080                 err = -ENOMEM;
9081                 goto out;
9082         }
9083
9084         trans = btrfs_start_transaction(tree_root, 0);
9085         if (IS_ERR(trans)) {
9086                 err = PTR_ERR(trans);
9087                 goto out_free;
9088         }
9089
9090         if (block_rsv)
9091                 trans->block_rsv = block_rsv;
9092
9093         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9094                 level = btrfs_header_level(root->node);
9095                 path->nodes[level] = btrfs_lock_root_node(root);
9096                 btrfs_set_lock_blocking(path->nodes[level]);
9097                 path->slots[level] = 0;
9098                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9099                 memset(&wc->update_progress, 0,
9100                        sizeof(wc->update_progress));
9101         } else {
9102                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9103                 memcpy(&wc->update_progress, &key,
9104                        sizeof(wc->update_progress));
9105
9106                 level = root_item->drop_level;
9107                 BUG_ON(level == 0);
9108                 path->lowest_level = level;
9109                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9110                 path->lowest_level = 0;
9111                 if (ret < 0) {
9112                         err = ret;
9113                         goto out_end_trans;
9114                 }
9115                 WARN_ON(ret > 0);
9116
9117                 /*
9118                  * unlock our path, this is safe because only this
9119                  * function is allowed to delete this snapshot
9120                  */
9121                 btrfs_unlock_up_safe(path, 0);
9122
9123                 level = btrfs_header_level(root->node);
9124                 while (1) {
9125                         btrfs_tree_lock(path->nodes[level]);
9126                         btrfs_set_lock_blocking(path->nodes[level]);
9127                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9128
9129                         ret = btrfs_lookup_extent_info(trans, fs_info,
9130                                                 path->nodes[level]->start,
9131                                                 level, 1, &wc->refs[level],
9132                                                 &wc->flags[level]);
9133                         if (ret < 0) {
9134                                 err = ret;
9135                                 goto out_end_trans;
9136                         }
9137                         BUG_ON(wc->refs[level] == 0);
9138
9139                         if (level == root_item->drop_level)
9140                                 break;
9141
9142                         btrfs_tree_unlock(path->nodes[level]);
9143                         path->locks[level] = 0;
9144                         WARN_ON(wc->refs[level] != 1);
9145                         level--;
9146                 }
9147         }
9148
9149         wc->level = level;
9150         wc->shared_level = -1;
9151         wc->stage = DROP_REFERENCE;
9152         wc->update_ref = update_ref;
9153         wc->keep_locks = 0;
9154         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9155
9156         while (1) {
9157
9158                 ret = walk_down_tree(trans, root, path, wc);
9159                 if (ret < 0) {
9160                         err = ret;
9161                         break;
9162                 }
9163
9164                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9165                 if (ret < 0) {
9166                         err = ret;
9167                         break;
9168                 }
9169
9170                 if (ret > 0) {
9171                         BUG_ON(wc->stage != DROP_REFERENCE);
9172                         break;
9173                 }
9174
9175                 if (wc->stage == DROP_REFERENCE) {
9176                         level = wc->level;
9177                         btrfs_node_key(path->nodes[level],
9178                                        &root_item->drop_progress,
9179                                        path->slots[level]);
9180                         root_item->drop_level = level;
9181                 }
9182
9183                 BUG_ON(wc->level == 0);
9184                 if (btrfs_should_end_transaction(trans) ||
9185                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
9186                         ret = btrfs_update_root(trans, tree_root,
9187                                                 &root->root_key,
9188                                                 root_item);
9189                         if (ret) {
9190                                 btrfs_abort_transaction(trans, ret);
9191                                 err = ret;
9192                                 goto out_end_trans;
9193                         }
9194
9195                         btrfs_end_transaction_throttle(trans);
9196                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
9197                                 btrfs_debug(fs_info,
9198                                             "drop snapshot early exit");
9199                                 err = -EAGAIN;
9200                                 goto out_free;
9201                         }
9202
9203                         trans = btrfs_start_transaction(tree_root, 0);
9204                         if (IS_ERR(trans)) {
9205                                 err = PTR_ERR(trans);
9206                                 goto out_free;
9207                         }
9208                         if (block_rsv)
9209                                 trans->block_rsv = block_rsv;
9210                 }
9211         }
9212         btrfs_release_path(path);
9213         if (err)
9214                 goto out_end_trans;
9215
9216         ret = btrfs_del_root(trans, &root->root_key);
9217         if (ret) {
9218                 btrfs_abort_transaction(trans, ret);
9219                 err = ret;
9220                 goto out_end_trans;
9221         }
9222
9223         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9224                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9225                                       NULL, NULL);
9226                 if (ret < 0) {
9227                         btrfs_abort_transaction(trans, ret);
9228                         err = ret;
9229                         goto out_end_trans;
9230                 } else if (ret > 0) {
9231                         /* if we fail to delete the orphan item this time
9232                          * around, it'll get picked up the next time.
9233                          *
9234                          * The most common failure here is just -ENOENT.
9235                          */
9236                         btrfs_del_orphan_item(trans, tree_root,
9237                                               root->root_key.objectid);
9238                 }
9239         }
9240
9241         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9242                 btrfs_add_dropped_root(trans, root);
9243         } else {
9244                 free_extent_buffer(root->node);
9245                 free_extent_buffer(root->commit_root);
9246                 btrfs_put_fs_root(root);
9247         }
9248         root_dropped = true;
9249 out_end_trans:
9250         btrfs_end_transaction_throttle(trans);
9251 out_free:
9252         kfree(wc);
9253         btrfs_free_path(path);
9254 out:
9255         /*
9256          * So if we need to stop dropping the snapshot for whatever reason we
9257          * need to make sure to add it back to the dead root list so that we
9258          * keep trying to do the work later.  This also cleans up roots if we
9259          * don't have it in the radix (like when we recover after a power fail
9260          * or unmount) so we don't leak memory.
9261          */
9262         if (!for_reloc && !root_dropped)
9263                 btrfs_add_dead_root(root);
9264         if (err && err != -EAGAIN)
9265                 btrfs_handle_fs_error(fs_info, err, NULL);
9266         return err;
9267 }
9268
9269 /*
9270  * drop subtree rooted at tree block 'node'.
9271  *
9272  * NOTE: this function will unlock and release tree block 'node'
9273  * only used by relocation code
9274  */
9275 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9276                         struct btrfs_root *root,
9277                         struct extent_buffer *node,
9278                         struct extent_buffer *parent)
9279 {
9280         struct btrfs_fs_info *fs_info = root->fs_info;
9281         struct btrfs_path *path;
9282         struct walk_control *wc;
9283         int level;
9284         int parent_level;
9285         int ret = 0;
9286         int wret;
9287
9288         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9289
9290         path = btrfs_alloc_path();
9291         if (!path)
9292                 return -ENOMEM;
9293
9294         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9295         if (!wc) {
9296                 btrfs_free_path(path);
9297                 return -ENOMEM;
9298         }
9299
9300         btrfs_assert_tree_locked(parent);
9301         parent_level = btrfs_header_level(parent);
9302         extent_buffer_get(parent);
9303         path->nodes[parent_level] = parent;
9304         path->slots[parent_level] = btrfs_header_nritems(parent);
9305
9306         btrfs_assert_tree_locked(node);
9307         level = btrfs_header_level(node);
9308         path->nodes[level] = node;
9309         path->slots[level] = 0;
9310         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9311
9312         wc->refs[parent_level] = 1;
9313         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9314         wc->level = level;
9315         wc->shared_level = -1;
9316         wc->stage = DROP_REFERENCE;
9317         wc->update_ref = 0;
9318         wc->keep_locks = 1;
9319         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9320
9321         while (1) {
9322                 wret = walk_down_tree(trans, root, path, wc);
9323                 if (wret < 0) {
9324                         ret = wret;
9325                         break;
9326                 }
9327
9328                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9329                 if (wret < 0)
9330                         ret = wret;
9331                 if (wret != 0)
9332                         break;
9333         }
9334
9335         kfree(wc);
9336         btrfs_free_path(path);
9337         return ret;
9338 }
9339
9340 static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
9341 {
9342         u64 num_devices;
9343         u64 stripped;
9344
9345         /*
9346          * if restripe for this chunk_type is on pick target profile and
9347          * return, otherwise do the usual balance
9348          */
9349         stripped = get_restripe_target(fs_info, flags);
9350         if (stripped)
9351                 return extended_to_chunk(stripped);
9352
9353         num_devices = fs_info->fs_devices->rw_devices;
9354
9355         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9356                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9357                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9358
9359         if (num_devices == 1) {
9360                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9361                 stripped = flags & ~stripped;
9362
9363                 /* turn raid0 into single device chunks */
9364                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9365                         return stripped;
9366
9367                 /* turn mirroring into duplication */
9368                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9369                              BTRFS_BLOCK_GROUP_RAID10))
9370                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9371         } else {
9372                 /* they already had raid on here, just return */
9373                 if (flags & stripped)
9374                         return flags;
9375
9376                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9377                 stripped = flags & ~stripped;
9378
9379                 /* switch duplicated blocks with raid1 */
9380                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9381                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9382
9383                 /* this is drive concat, leave it alone */
9384         }
9385
9386         return flags;
9387 }
9388
9389 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9390 {
9391         struct btrfs_space_info *sinfo = cache->space_info;
9392         u64 num_bytes;
9393         u64 min_allocable_bytes;
9394         int ret = -ENOSPC;
9395
9396         /*
9397          * We need some metadata space and system metadata space for
9398          * allocating chunks in some corner cases until we force to set
9399          * it to be readonly.
9400          */
9401         if ((sinfo->flags &
9402              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9403             !force)
9404                 min_allocable_bytes = SZ_1M;
9405         else
9406                 min_allocable_bytes = 0;
9407
9408         spin_lock(&sinfo->lock);
9409         spin_lock(&cache->lock);
9410
9411         if (cache->ro) {
9412                 cache->ro++;
9413                 ret = 0;
9414                 goto out;
9415         }
9416
9417         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9418                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9419
9420         if (btrfs_space_info_used(sinfo, true) + num_bytes +
9421             min_allocable_bytes <= sinfo->total_bytes) {
9422                 sinfo->bytes_readonly += num_bytes;
9423                 cache->ro++;
9424                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9425                 ret = 0;
9426         }
9427 out:
9428         spin_unlock(&cache->lock);
9429         spin_unlock(&sinfo->lock);
9430         return ret;
9431 }
9432
9433 int btrfs_inc_block_group_ro(struct btrfs_block_group_cache *cache)
9434
9435 {
9436         struct btrfs_fs_info *fs_info = cache->fs_info;
9437         struct btrfs_trans_handle *trans;
9438         u64 alloc_flags;
9439         int ret;
9440
9441 again:
9442         trans = btrfs_join_transaction(fs_info->extent_root);
9443         if (IS_ERR(trans))
9444                 return PTR_ERR(trans);
9445
9446         /*
9447          * we're not allowed to set block groups readonly after the dirty
9448          * block groups cache has started writing.  If it already started,
9449          * back off and let this transaction commit
9450          */
9451         mutex_lock(&fs_info->ro_block_group_mutex);
9452         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9453                 u64 transid = trans->transid;
9454
9455                 mutex_unlock(&fs_info->ro_block_group_mutex);
9456                 btrfs_end_transaction(trans);
9457
9458                 ret = btrfs_wait_for_commit(fs_info, transid);
9459                 if (ret)
9460                         return ret;
9461                 goto again;
9462         }
9463
9464         /*
9465          * if we are changing raid levels, try to allocate a corresponding
9466          * block group with the new raid level.
9467          */
9468         alloc_flags = update_block_group_flags(fs_info, cache->flags);
9469         if (alloc_flags != cache->flags) {
9470                 ret = do_chunk_alloc(trans, alloc_flags,
9471                                      CHUNK_ALLOC_FORCE);
9472                 /*
9473                  * ENOSPC is allowed here, we may have enough space
9474                  * already allocated at the new raid level to
9475                  * carry on
9476                  */
9477                 if (ret == -ENOSPC)
9478                         ret = 0;
9479                 if (ret < 0)
9480                         goto out;
9481         }
9482
9483         ret = inc_block_group_ro(cache, 0);
9484         if (!ret)
9485                 goto out;
9486         alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
9487         ret = do_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
9488         if (ret < 0)
9489                 goto out;
9490         ret = inc_block_group_ro(cache, 0);
9491 out:
9492         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9493                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
9494                 mutex_lock(&fs_info->chunk_mutex);
9495                 check_system_chunk(trans, alloc_flags);
9496                 mutex_unlock(&fs_info->chunk_mutex);
9497         }
9498         mutex_unlock(&fs_info->ro_block_group_mutex);
9499
9500         btrfs_end_transaction(trans);
9501         return ret;
9502 }
9503
9504 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
9505 {
9506         u64 alloc_flags = get_alloc_profile(trans->fs_info, type);
9507
9508         return do_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
9509 }
9510
9511 /*
9512  * helper to account the unused space of all the readonly block group in the
9513  * space_info. takes mirrors into account.
9514  */
9515 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9516 {
9517         struct btrfs_block_group_cache *block_group;
9518         u64 free_bytes = 0;
9519         int factor;
9520
9521         /* It's df, we don't care if it's racy */
9522         if (list_empty(&sinfo->ro_bgs))
9523                 return 0;
9524
9525         spin_lock(&sinfo->lock);
9526         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9527                 spin_lock(&block_group->lock);
9528
9529                 if (!block_group->ro) {
9530                         spin_unlock(&block_group->lock);
9531                         continue;
9532                 }
9533
9534                 factor = btrfs_bg_type_to_factor(block_group->flags);
9535                 free_bytes += (block_group->key.offset -
9536                                btrfs_block_group_used(&block_group->item)) *
9537                                factor;
9538
9539                 spin_unlock(&block_group->lock);
9540         }
9541         spin_unlock(&sinfo->lock);
9542
9543         return free_bytes;
9544 }
9545
9546 void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
9547 {
9548         struct btrfs_space_info *sinfo = cache->space_info;
9549         u64 num_bytes;
9550
9551         BUG_ON(!cache->ro);
9552
9553         spin_lock(&sinfo->lock);
9554         spin_lock(&cache->lock);
9555         if (!--cache->ro) {
9556                 num_bytes = cache->key.offset - cache->reserved -
9557                             cache->pinned - cache->bytes_super -
9558                             btrfs_block_group_used(&cache->item);
9559                 sinfo->bytes_readonly -= num_bytes;
9560                 list_del_init(&cache->ro_list);
9561         }
9562         spin_unlock(&cache->lock);
9563         spin_unlock(&sinfo->lock);
9564 }
9565
9566 /*
9567  * checks to see if its even possible to relocate this block group.
9568  *
9569  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9570  * ok to go ahead and try.
9571  */
9572 int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)
9573 {
9574         struct btrfs_root *root = fs_info->extent_root;
9575         struct btrfs_block_group_cache *block_group;
9576         struct btrfs_space_info *space_info;
9577         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
9578         struct btrfs_device *device;
9579         struct btrfs_trans_handle *trans;
9580         u64 min_free;
9581         u64 dev_min = 1;
9582         u64 dev_nr = 0;
9583         u64 target;
9584         int debug;
9585         int index;
9586         int full = 0;
9587         int ret = 0;
9588
9589         debug = btrfs_test_opt(fs_info, ENOSPC_DEBUG);
9590
9591         block_group = btrfs_lookup_block_group(fs_info, bytenr);
9592
9593         /* odd, couldn't find the block group, leave it alone */
9594         if (!block_group) {
9595                 if (debug)
9596                         btrfs_warn(fs_info,
9597                                    "can't find block group for bytenr %llu",
9598                                    bytenr);
9599                 return -1;
9600         }
9601
9602         min_free = btrfs_block_group_used(&block_group->item);
9603
9604         /* no bytes used, we're good */
9605         if (!min_free)
9606                 goto out;
9607
9608         space_info = block_group->space_info;
9609         spin_lock(&space_info->lock);
9610
9611         full = space_info->full;
9612
9613         /*
9614          * if this is the last block group we have in this space, we can't
9615          * relocate it unless we're able to allocate a new chunk below.
9616          *
9617          * Otherwise, we need to make sure we have room in the space to handle
9618          * all of the extents from this block group.  If we can, we're good
9619          */
9620         if ((space_info->total_bytes != block_group->key.offset) &&
9621             (btrfs_space_info_used(space_info, false) + min_free <
9622              space_info->total_bytes)) {
9623                 spin_unlock(&space_info->lock);
9624                 goto out;
9625         }
9626         spin_unlock(&space_info->lock);
9627
9628         /*
9629          * ok we don't have enough space, but maybe we have free space on our
9630          * devices to allocate new chunks for relocation, so loop through our
9631          * alloc devices and guess if we have enough space.  if this block
9632          * group is going to be restriped, run checks against the target
9633          * profile instead of the current one.
9634          */
9635         ret = -1;
9636
9637         /*
9638          * index:
9639          *      0: raid10
9640          *      1: raid1
9641          *      2: dup
9642          *      3: raid0
9643          *      4: single
9644          */
9645         target = get_restripe_target(fs_info, block_group->flags);
9646         if (target) {
9647                 index = btrfs_bg_flags_to_raid_index(extended_to_chunk(target));
9648         } else {
9649                 /*
9650                  * this is just a balance, so if we were marked as full
9651                  * we know there is no space for a new chunk
9652                  */
9653                 if (full) {
9654                         if (debug)
9655                                 btrfs_warn(fs_info,
9656                                            "no space to alloc new chunk for block group %llu",
9657                                            block_group->key.objectid);
9658                         goto out;
9659                 }
9660
9661                 index = btrfs_bg_flags_to_raid_index(block_group->flags);
9662         }
9663
9664         if (index == BTRFS_RAID_RAID10) {
9665                 dev_min = 4;
9666                 /* Divide by 2 */
9667                 min_free >>= 1;
9668         } else if (index == BTRFS_RAID_RAID1) {
9669                 dev_min = 2;
9670         } else if (index == BTRFS_RAID_DUP) {
9671                 /* Multiply by 2 */
9672                 min_free <<= 1;
9673         } else if (index == BTRFS_RAID_RAID0) {
9674                 dev_min = fs_devices->rw_devices;
9675                 min_free = div64_u64(min_free, dev_min);
9676         }
9677
9678         /* We need to do this so that we can look at pending chunks */
9679         trans = btrfs_join_transaction(root);
9680         if (IS_ERR(trans)) {
9681                 ret = PTR_ERR(trans);
9682                 goto out;
9683         }
9684
9685         mutex_lock(&fs_info->chunk_mutex);
9686         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9687                 u64 dev_offset;
9688
9689                 /*
9690                  * check to make sure we can actually find a chunk with enough
9691                  * space to fit our block group in.
9692                  */
9693                 if (device->total_bytes > device->bytes_used + min_free &&
9694                     !test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
9695                         ret = find_free_dev_extent(trans, device, min_free,
9696                                                    &dev_offset, NULL);
9697                         if (!ret)
9698                                 dev_nr++;
9699
9700                         if (dev_nr >= dev_min)
9701                                 break;
9702
9703                         ret = -1;
9704                 }
9705         }
9706         if (debug && ret == -1)
9707                 btrfs_warn(fs_info,
9708                            "no space to allocate a new chunk for block group %llu",
9709                            block_group->key.objectid);
9710         mutex_unlock(&fs_info->chunk_mutex);
9711         btrfs_end_transaction(trans);
9712 out:
9713         btrfs_put_block_group(block_group);
9714         return ret;
9715 }
9716
9717 static int find_first_block_group(struct btrfs_fs_info *fs_info,
9718                                   struct btrfs_path *path,
9719                                   struct btrfs_key *key)
9720 {
9721         struct btrfs_root *root = fs_info->extent_root;
9722         int ret = 0;
9723         struct btrfs_key found_key;
9724         struct extent_buffer *leaf;
9725         struct btrfs_block_group_item bg;
9726         u64 flags;
9727         int slot;
9728
9729         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9730         if (ret < 0)
9731                 goto out;
9732
9733         while (1) {
9734                 slot = path->slots[0];
9735                 leaf = path->nodes[0];
9736                 if (slot >= btrfs_header_nritems(leaf)) {
9737                         ret = btrfs_next_leaf(root, path);
9738                         if (ret == 0)
9739                                 continue;
9740                         if (ret < 0)
9741                                 goto out;
9742                         break;
9743                 }
9744                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9745
9746                 if (found_key.objectid >= key->objectid &&
9747                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9748                         struct extent_map_tree *em_tree;
9749                         struct extent_map *em;
9750
9751                         em_tree = &root->fs_info->mapping_tree.map_tree;
9752                         read_lock(&em_tree->lock);
9753                         em = lookup_extent_mapping(em_tree, found_key.objectid,
9754                                                    found_key.offset);
9755                         read_unlock(&em_tree->lock);
9756                         if (!em) {
9757                                 btrfs_err(fs_info,
9758                         "logical %llu len %llu found bg but no related chunk",
9759                                           found_key.objectid, found_key.offset);
9760                                 ret = -ENOENT;
9761                         } else if (em->start != found_key.objectid ||
9762                                    em->len != found_key.offset) {
9763                                 btrfs_err(fs_info,
9764                 "block group %llu len %llu mismatch with chunk %llu len %llu",
9765                                           found_key.objectid, found_key.offset,
9766                                           em->start, em->len);
9767                                 ret = -EUCLEAN;
9768                         } else {
9769                                 read_extent_buffer(leaf, &bg,
9770                                         btrfs_item_ptr_offset(leaf, slot),
9771                                         sizeof(bg));
9772                                 flags = btrfs_block_group_flags(&bg) &
9773                                         BTRFS_BLOCK_GROUP_TYPE_MASK;
9774
9775                                 if (flags != (em->map_lookup->type &
9776                                               BTRFS_BLOCK_GROUP_TYPE_MASK)) {
9777                                         btrfs_err(fs_info,
9778 "block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
9779                                                 found_key.objectid,
9780                                                 found_key.offset, flags,
9781                                                 (BTRFS_BLOCK_GROUP_TYPE_MASK &
9782                                                  em->map_lookup->type));
9783                                         ret = -EUCLEAN;
9784                                 } else {
9785                                         ret = 0;
9786                                 }
9787                         }
9788                         free_extent_map(em);
9789                         goto out;
9790                 }
9791                 path->slots[0]++;
9792         }
9793 out:
9794         return ret;
9795 }
9796
9797 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9798 {
9799         struct btrfs_block_group_cache *block_group;
9800         u64 last = 0;
9801
9802         while (1) {
9803                 struct inode *inode;
9804
9805                 block_group = btrfs_lookup_first_block_group(info, last);
9806                 while (block_group) {
9807                         wait_block_group_cache_done(block_group);
9808                         spin_lock(&block_group->lock);
9809                         if (block_group->iref)
9810                                 break;
9811                         spin_unlock(&block_group->lock);
9812                         block_group = next_block_group(info, block_group);
9813                 }
9814                 if (!block_group) {
9815                         if (last == 0)
9816                                 break;
9817                         last = 0;
9818                         continue;
9819                 }
9820
9821                 inode = block_group->inode;
9822                 block_group->iref = 0;
9823                 block_group->inode = NULL;
9824                 spin_unlock(&block_group->lock);
9825                 ASSERT(block_group->io_ctl.inode == NULL);
9826                 iput(inode);
9827                 last = block_group->key.objectid + block_group->key.offset;
9828                 btrfs_put_block_group(block_group);
9829         }
9830 }
9831
9832 /*
9833  * Must be called only after stopping all workers, since we could have block
9834  * group caching kthreads running, and therefore they could race with us if we
9835  * freed the block groups before stopping them.
9836  */
9837 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9838 {
9839         struct btrfs_block_group_cache *block_group;
9840         struct btrfs_space_info *space_info;
9841         struct btrfs_caching_control *caching_ctl;
9842         struct rb_node *n;
9843
9844         down_write(&info->commit_root_sem);
9845         while (!list_empty(&info->caching_block_groups)) {
9846                 caching_ctl = list_entry(info->caching_block_groups.next,
9847                                          struct btrfs_caching_control, list);
9848                 list_del(&caching_ctl->list);
9849                 put_caching_control(caching_ctl);
9850         }
9851         up_write(&info->commit_root_sem);
9852
9853         spin_lock(&info->unused_bgs_lock);
9854         while (!list_empty(&info->unused_bgs)) {
9855                 block_group = list_first_entry(&info->unused_bgs,
9856                                                struct btrfs_block_group_cache,
9857                                                bg_list);
9858                 list_del_init(&block_group->bg_list);
9859                 btrfs_put_block_group(block_group);
9860         }
9861         spin_unlock(&info->unused_bgs_lock);
9862
9863         spin_lock(&info->block_group_cache_lock);
9864         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9865                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9866                                        cache_node);
9867                 rb_erase(&block_group->cache_node,
9868                          &info->block_group_cache_tree);
9869                 RB_CLEAR_NODE(&block_group->cache_node);
9870                 spin_unlock(&info->block_group_cache_lock);
9871
9872                 down_write(&block_group->space_info->groups_sem);
9873                 list_del(&block_group->list);
9874                 up_write(&block_group->space_info->groups_sem);
9875
9876                 /*
9877                  * We haven't cached this block group, which means we could
9878                  * possibly have excluded extents on this block group.
9879                  */
9880                 if (block_group->cached == BTRFS_CACHE_NO ||
9881                     block_group->cached == BTRFS_CACHE_ERROR)
9882                         free_excluded_extents(block_group);
9883
9884                 btrfs_remove_free_space_cache(block_group);
9885                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
9886                 ASSERT(list_empty(&block_group->dirty_list));
9887                 ASSERT(list_empty(&block_group->io_list));
9888                 ASSERT(list_empty(&block_group->bg_list));
9889                 ASSERT(atomic_read(&block_group->count) == 1);
9890                 btrfs_put_block_group(block_group);
9891
9892                 spin_lock(&info->block_group_cache_lock);
9893         }
9894         spin_unlock(&info->block_group_cache_lock);
9895
9896         /* now that all the block groups are freed, go through and
9897          * free all the space_info structs.  This is only called during
9898          * the final stages of unmount, and so we know nobody is
9899          * using them.  We call synchronize_rcu() once before we start,
9900          * just to be on the safe side.
9901          */
9902         synchronize_rcu();
9903
9904         release_global_block_rsv(info);
9905
9906         while (!list_empty(&info->space_info)) {
9907                 int i;
9908
9909                 space_info = list_entry(info->space_info.next,
9910                                         struct btrfs_space_info,
9911                                         list);
9912
9913                 /*
9914                  * Do not hide this behind enospc_debug, this is actually
9915                  * important and indicates a real bug if this happens.
9916                  */
9917                 if (WARN_ON(space_info->bytes_pinned > 0 ||
9918                             space_info->bytes_reserved > 0 ||
9919                             space_info->bytes_may_use > 0))
9920                         dump_space_info(info, space_info, 0, 0);
9921                 list_del(&space_info->list);
9922                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9923                         struct kobject *kobj;
9924                         kobj = space_info->block_group_kobjs[i];
9925                         space_info->block_group_kobjs[i] = NULL;
9926                         if (kobj) {
9927                                 kobject_del(kobj);
9928                                 kobject_put(kobj);
9929                         }
9930                 }
9931                 kobject_del(&space_info->kobj);
9932                 kobject_put(&space_info->kobj);
9933         }
9934         return 0;
9935 }
9936
9937 /* link_block_group will queue up kobjects to add when we're reclaim-safe */
9938 void btrfs_add_raid_kobjects(struct btrfs_fs_info *fs_info)
9939 {
9940         struct btrfs_space_info *space_info;
9941         struct raid_kobject *rkobj;
9942         LIST_HEAD(list);
9943         int index;
9944         int ret = 0;
9945
9946         spin_lock(&fs_info->pending_raid_kobjs_lock);
9947         list_splice_init(&fs_info->pending_raid_kobjs, &list);
9948         spin_unlock(&fs_info->pending_raid_kobjs_lock);
9949
9950         list_for_each_entry(rkobj, &list, list) {
9951                 space_info = __find_space_info(fs_info, rkobj->flags);
9952                 index = btrfs_bg_flags_to_raid_index(rkobj->flags);
9953
9954                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9955                                   "%s", get_raid_name(index));
9956                 if (ret) {
9957                         kobject_put(&rkobj->kobj);
9958                         break;
9959                 }
9960         }
9961         if (ret)
9962                 btrfs_warn(fs_info,
9963                            "failed to add kobject for block cache, ignoring");
9964 }
9965
9966 static void link_block_group(struct btrfs_block_group_cache *cache)
9967 {
9968         struct btrfs_space_info *space_info = cache->space_info;
9969         struct btrfs_fs_info *fs_info = cache->fs_info;
9970         int index = btrfs_bg_flags_to_raid_index(cache->flags);
9971         bool first = false;
9972
9973         down_write(&space_info->groups_sem);
9974         if (list_empty(&space_info->block_groups[index]))
9975                 first = true;
9976         list_add_tail(&cache->list, &space_info->block_groups[index]);
9977         up_write(&space_info->groups_sem);
9978
9979         if (first) {
9980                 struct raid_kobject *rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9981                 if (!rkobj) {
9982                         btrfs_warn(cache->fs_info,
9983                                 "couldn't alloc memory for raid level kobject");
9984                         return;
9985                 }
9986                 rkobj->flags = cache->flags;
9987                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9988
9989                 spin_lock(&fs_info->pending_raid_kobjs_lock);
9990                 list_add_tail(&rkobj->list, &fs_info->pending_raid_kobjs);
9991                 spin_unlock(&fs_info->pending_raid_kobjs_lock);
9992                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9993         }
9994 }
9995
9996 static struct btrfs_block_group_cache *
9997 btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
9998                                u64 start, u64 size)
9999 {
10000         struct btrfs_block_group_cache *cache;
10001
10002         cache = kzalloc(sizeof(*cache), GFP_NOFS);
10003         if (!cache)
10004                 return NULL;
10005
10006         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
10007                                         GFP_NOFS);
10008         if (!cache->free_space_ctl) {
10009                 kfree(cache);
10010                 return NULL;
10011         }
10012
10013         cache->key.objectid = start;
10014         cache->key.offset = size;
10015         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10016
10017         cache->fs_info = fs_info;
10018         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
10019         set_free_space_tree_thresholds(cache);
10020
10021         atomic_set(&cache->count, 1);
10022         spin_lock_init(&cache->lock);
10023         init_rwsem(&cache->data_rwsem);
10024         INIT_LIST_HEAD(&cache->list);
10025         INIT_LIST_HEAD(&cache->cluster_list);
10026         INIT_LIST_HEAD(&cache->bg_list);
10027         INIT_LIST_HEAD(&cache->ro_list);
10028         INIT_LIST_HEAD(&cache->dirty_list);
10029         INIT_LIST_HEAD(&cache->io_list);
10030         btrfs_init_free_space_ctl(cache);
10031         atomic_set(&cache->trimming, 0);
10032         mutex_init(&cache->free_space_lock);
10033         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
10034
10035         return cache;
10036 }
10037
10038
10039 /*
10040  * Iterate all chunks and verify that each of them has the corresponding block
10041  * group
10042  */
10043 static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
10044 {
10045         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
10046         struct extent_map *em;
10047         struct btrfs_block_group_cache *bg;
10048         u64 start = 0;
10049         int ret = 0;
10050
10051         while (1) {
10052                 read_lock(&map_tree->map_tree.lock);
10053                 /*
10054                  * lookup_extent_mapping will return the first extent map
10055                  * intersecting the range, so setting @len to 1 is enough to
10056                  * get the first chunk.
10057                  */
10058                 em = lookup_extent_mapping(&map_tree->map_tree, start, 1);
10059                 read_unlock(&map_tree->map_tree.lock);
10060                 if (!em)
10061                         break;
10062
10063                 bg = btrfs_lookup_block_group(fs_info, em->start);
10064                 if (!bg) {
10065                         btrfs_err(fs_info,
10066         "chunk start=%llu len=%llu doesn't have corresponding block group",
10067                                      em->start, em->len);
10068                         ret = -EUCLEAN;
10069                         free_extent_map(em);
10070                         break;
10071                 }
10072                 if (bg->key.objectid != em->start ||
10073                     bg->key.offset != em->len ||
10074                     (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
10075                     (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
10076                         btrfs_err(fs_info,
10077 "chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
10078                                 em->start, em->len,
10079                                 em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
10080                                 bg->key.objectid, bg->key.offset,
10081                                 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
10082                         ret = -EUCLEAN;
10083                         free_extent_map(em);
10084                         btrfs_put_block_group(bg);
10085                         break;
10086                 }
10087                 start = em->start + em->len;
10088                 free_extent_map(em);
10089                 btrfs_put_block_group(bg);
10090         }
10091         return ret;
10092 }
10093
10094 int btrfs_read_block_groups(struct btrfs_fs_info *info)
10095 {
10096         struct btrfs_path *path;
10097         int ret;
10098         struct btrfs_block_group_cache *cache;
10099         struct btrfs_space_info *space_info;
10100         struct btrfs_key key;
10101         struct btrfs_key found_key;
10102         struct extent_buffer *leaf;
10103         int need_clear = 0;
10104         u64 cache_gen;
10105         u64 feature;
10106         int mixed;
10107
10108         feature = btrfs_super_incompat_flags(info->super_copy);
10109         mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
10110
10111         key.objectid = 0;
10112         key.offset = 0;
10113         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10114         path = btrfs_alloc_path();
10115         if (!path)
10116                 return -ENOMEM;
10117         path->reada = READA_FORWARD;
10118
10119         cache_gen = btrfs_super_cache_generation(info->super_copy);
10120         if (btrfs_test_opt(info, SPACE_CACHE) &&
10121             btrfs_super_generation(info->super_copy) != cache_gen)
10122                 need_clear = 1;
10123         if (btrfs_test_opt(info, CLEAR_CACHE))
10124                 need_clear = 1;
10125
10126         while (1) {
10127                 ret = find_first_block_group(info, path, &key);
10128                 if (ret > 0)
10129                         break;
10130                 if (ret != 0)
10131                         goto error;
10132
10133                 leaf = path->nodes[0];
10134                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10135
10136                 cache = btrfs_create_block_group_cache(info, found_key.objectid,
10137                                                        found_key.offset);
10138                 if (!cache) {
10139                         ret = -ENOMEM;
10140                         goto error;
10141                 }
10142
10143                 if (need_clear) {
10144                         /*
10145                          * When we mount with old space cache, we need to
10146                          * set BTRFS_DC_CLEAR and set dirty flag.
10147                          *
10148                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10149                          *    truncate the old free space cache inode and
10150                          *    setup a new one.
10151                          * b) Setting 'dirty flag' makes sure that we flush
10152                          *    the new space cache info onto disk.
10153                          */
10154                         if (btrfs_test_opt(info, SPACE_CACHE))
10155                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
10156                 }
10157
10158                 read_extent_buffer(leaf, &cache->item,
10159                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
10160                                    sizeof(cache->item));
10161                 cache->flags = btrfs_block_group_flags(&cache->item);
10162                 if (!mixed &&
10163                     ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
10164                     (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
10165                         btrfs_err(info,
10166 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
10167                                   cache->key.objectid);
10168                         ret = -EINVAL;
10169                         goto error;
10170                 }
10171
10172                 key.objectid = found_key.objectid + found_key.offset;
10173                 btrfs_release_path(path);
10174
10175                 /*
10176                  * We need to exclude the super stripes now so that the space
10177                  * info has super bytes accounted for, otherwise we'll think
10178                  * we have more space than we actually do.
10179                  */
10180                 ret = exclude_super_stripes(cache);
10181                 if (ret) {
10182                         /*
10183                          * We may have excluded something, so call this just in
10184                          * case.
10185                          */
10186                         free_excluded_extents(cache);
10187                         btrfs_put_block_group(cache);
10188                         goto error;
10189                 }
10190
10191                 /*
10192                  * check for two cases, either we are full, and therefore
10193                  * don't need to bother with the caching work since we won't
10194                  * find any space, or we are empty, and we can just add all
10195                  * the space in and be done with it.  This saves us _alot_ of
10196                  * time, particularly in the full case.
10197                  */
10198                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10199                         cache->last_byte_to_unpin = (u64)-1;
10200                         cache->cached = BTRFS_CACHE_FINISHED;
10201                         free_excluded_extents(cache);
10202                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10203                         cache->last_byte_to_unpin = (u64)-1;
10204                         cache->cached = BTRFS_CACHE_FINISHED;
10205                         add_new_free_space(cache, found_key.objectid,
10206                                            found_key.objectid +
10207                                            found_key.offset);
10208                         free_excluded_extents(cache);
10209                 }
10210
10211                 ret = btrfs_add_block_group_cache(info, cache);
10212                 if (ret) {
10213                         btrfs_remove_free_space_cache(cache);
10214                         btrfs_put_block_group(cache);
10215                         goto error;
10216                 }
10217
10218                 trace_btrfs_add_block_group(info, cache, 0);
10219                 update_space_info(info, cache->flags, found_key.offset,
10220                                   btrfs_block_group_used(&cache->item),
10221                                   cache->bytes_super, &space_info);
10222
10223                 cache->space_info = space_info;
10224
10225                 link_block_group(cache);
10226
10227                 set_avail_alloc_bits(info, cache->flags);
10228                 if (btrfs_chunk_readonly(info, cache->key.objectid)) {
10229                         inc_block_group_ro(cache, 1);
10230                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10231                         ASSERT(list_empty(&cache->bg_list));
10232                         btrfs_mark_bg_unused(cache);
10233                 }
10234         }
10235
10236         list_for_each_entry_rcu(space_info, &info->space_info, list) {
10237                 if (!(get_alloc_profile(info, space_info->flags) &
10238                       (BTRFS_BLOCK_GROUP_RAID10 |
10239                        BTRFS_BLOCK_GROUP_RAID1 |
10240                        BTRFS_BLOCK_GROUP_RAID5 |
10241                        BTRFS_BLOCK_GROUP_RAID6 |
10242                        BTRFS_BLOCK_GROUP_DUP)))
10243                         continue;
10244                 /*
10245                  * avoid allocating from un-mirrored block group if there are
10246                  * mirrored block groups.
10247                  */
10248                 list_for_each_entry(cache,
10249                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10250                                 list)
10251                         inc_block_group_ro(cache, 1);
10252                 list_for_each_entry(cache,
10253                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10254                                 list)
10255                         inc_block_group_ro(cache, 1);
10256         }
10257
10258         btrfs_add_raid_kobjects(info);
10259         init_global_block_rsv(info);
10260         ret = check_chunk_block_group_mappings(info);
10261 error:
10262         btrfs_free_path(path);
10263         return ret;
10264 }
10265
10266 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
10267 {
10268         struct btrfs_fs_info *fs_info = trans->fs_info;
10269         struct btrfs_block_group_cache *block_group;
10270         struct btrfs_root *extent_root = fs_info->extent_root;
10271         struct btrfs_block_group_item item;
10272         struct btrfs_key key;
10273         int ret = 0;
10274
10275         if (!trans->can_flush_pending_bgs)
10276                 return;
10277
10278         while (!list_empty(&trans->new_bgs)) {
10279                 block_group = list_first_entry(&trans->new_bgs,
10280                                                struct btrfs_block_group_cache,
10281                                                bg_list);
10282                 if (ret)
10283                         goto next;
10284
10285                 spin_lock(&block_group->lock);
10286                 memcpy(&item, &block_group->item, sizeof(item));
10287                 memcpy(&key, &block_group->key, sizeof(key));
10288                 spin_unlock(&block_group->lock);
10289
10290                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10291                                         sizeof(item));
10292                 if (ret)
10293                         btrfs_abort_transaction(trans, ret);
10294                 ret = btrfs_finish_chunk_alloc(trans, key.objectid, key.offset);
10295                 if (ret)
10296                         btrfs_abort_transaction(trans, ret);
10297                 add_block_group_free_space(trans, block_group);
10298                 /* already aborted the transaction if it failed. */
10299 next:
10300                 list_del_init(&block_group->bg_list);
10301         }
10302         btrfs_trans_release_chunk_metadata(trans);
10303 }
10304
10305 int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
10306                            u64 type, u64 chunk_offset, u64 size)
10307 {
10308         struct btrfs_fs_info *fs_info = trans->fs_info;
10309         struct btrfs_block_group_cache *cache;
10310         int ret;
10311
10312         btrfs_set_log_full_commit(fs_info, trans);
10313
10314         cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
10315         if (!cache)
10316                 return -ENOMEM;
10317
10318         btrfs_set_block_group_used(&cache->item, bytes_used);
10319         btrfs_set_block_group_chunk_objectid(&cache->item,
10320                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID);
10321         btrfs_set_block_group_flags(&cache->item, type);
10322
10323         cache->flags = type;
10324         cache->last_byte_to_unpin = (u64)-1;
10325         cache->cached = BTRFS_CACHE_FINISHED;
10326         cache->needs_free_space = 1;
10327         ret = exclude_super_stripes(cache);
10328         if (ret) {
10329                 /*
10330                  * We may have excluded something, so call this just in
10331                  * case.
10332                  */
10333                 free_excluded_extents(cache);
10334                 btrfs_put_block_group(cache);
10335                 return ret;
10336         }
10337
10338         add_new_free_space(cache, chunk_offset, chunk_offset + size);
10339
10340         free_excluded_extents(cache);
10341
10342 #ifdef CONFIG_BTRFS_DEBUG
10343         if (btrfs_should_fragment_free_space(cache)) {
10344                 u64 new_bytes_used = size - bytes_used;
10345
10346                 bytes_used += new_bytes_used >> 1;
10347                 fragment_free_space(cache);
10348         }
10349 #endif
10350         /*
10351          * Ensure the corresponding space_info object is created and
10352          * assigned to our block group. We want our bg to be added to the rbtree
10353          * with its ->space_info set.
10354          */
10355         cache->space_info = __find_space_info(fs_info, cache->flags);
10356         ASSERT(cache->space_info);
10357
10358         ret = btrfs_add_block_group_cache(fs_info, cache);
10359         if (ret) {
10360                 btrfs_remove_free_space_cache(cache);
10361                 btrfs_put_block_group(cache);
10362                 return ret;
10363         }
10364
10365         /*
10366          * Now that our block group has its ->space_info set and is inserted in
10367          * the rbtree, update the space info's counters.
10368          */
10369         trace_btrfs_add_block_group(fs_info, cache, 1);
10370         update_space_info(fs_info, cache->flags, size, bytes_used,
10371                                 cache->bytes_super, &cache->space_info);
10372         update_global_block_rsv(fs_info);
10373
10374         link_block_group(cache);
10375
10376         list_add_tail(&cache->bg_list, &trans->new_bgs);
10377
10378         set_avail_alloc_bits(fs_info, type);
10379         return 0;
10380 }
10381
10382 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10383 {
10384         u64 extra_flags = chunk_to_extended(flags) &
10385                                 BTRFS_EXTENDED_PROFILE_MASK;
10386
10387         write_seqlock(&fs_info->profiles_lock);
10388         if (flags & BTRFS_BLOCK_GROUP_DATA)
10389                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10390         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10391                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10392         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10393                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10394         write_sequnlock(&fs_info->profiles_lock);
10395 }
10396
10397 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10398                              u64 group_start, struct extent_map *em)
10399 {
10400         struct btrfs_fs_info *fs_info = trans->fs_info;
10401         struct btrfs_root *root = fs_info->extent_root;
10402         struct btrfs_path *path;
10403         struct btrfs_block_group_cache *block_group;
10404         struct btrfs_free_cluster *cluster;
10405         struct btrfs_root *tree_root = fs_info->tree_root;
10406         struct btrfs_key key;
10407         struct inode *inode;
10408         struct kobject *kobj = NULL;
10409         int ret;
10410         int index;
10411         int factor;
10412         struct btrfs_caching_control *caching_ctl = NULL;
10413         bool remove_em;
10414
10415         block_group = btrfs_lookup_block_group(fs_info, group_start);
10416         BUG_ON(!block_group);
10417         BUG_ON(!block_group->ro);
10418
10419         trace_btrfs_remove_block_group(block_group);
10420         /*
10421          * Free the reserved super bytes from this block group before
10422          * remove it.
10423          */
10424         free_excluded_extents(block_group);
10425         btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
10426                                   block_group->key.offset);
10427
10428         memcpy(&key, &block_group->key, sizeof(key));
10429         index = btrfs_bg_flags_to_raid_index(block_group->flags);
10430         factor = btrfs_bg_type_to_factor(block_group->flags);
10431
10432         /* make sure this block group isn't part of an allocation cluster */
10433         cluster = &fs_info->data_alloc_cluster;
10434         spin_lock(&cluster->refill_lock);
10435         btrfs_return_cluster_to_free_space(block_group, cluster);
10436         spin_unlock(&cluster->refill_lock);
10437
10438         /*
10439          * make sure this block group isn't part of a metadata
10440          * allocation cluster
10441          */
10442         cluster = &fs_info->meta_alloc_cluster;
10443         spin_lock(&cluster->refill_lock);
10444         btrfs_return_cluster_to_free_space(block_group, cluster);
10445         spin_unlock(&cluster->refill_lock);
10446
10447         path = btrfs_alloc_path();
10448         if (!path) {
10449                 ret = -ENOMEM;
10450                 goto out;
10451         }
10452
10453         /*
10454          * get the inode first so any iput calls done for the io_list
10455          * aren't the final iput (no unlinks allowed now)
10456          */
10457         inode = lookup_free_space_inode(fs_info, block_group, path);
10458
10459         mutex_lock(&trans->transaction->cache_write_mutex);
10460         /*
10461          * make sure our free spache cache IO is done before remove the
10462          * free space inode
10463          */
10464         spin_lock(&trans->transaction->dirty_bgs_lock);
10465         if (!list_empty(&block_group->io_list)) {
10466                 list_del_init(&block_group->io_list);
10467
10468                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10469
10470                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10471                 btrfs_wait_cache_io(trans, block_group, path);
10472                 btrfs_put_block_group(block_group);
10473                 spin_lock(&trans->transaction->dirty_bgs_lock);
10474         }
10475
10476         if (!list_empty(&block_group->dirty_list)) {
10477                 list_del_init(&block_group->dirty_list);
10478                 btrfs_put_block_group(block_group);
10479         }
10480         spin_unlock(&trans->transaction->dirty_bgs_lock);
10481         mutex_unlock(&trans->transaction->cache_write_mutex);
10482
10483         if (!IS_ERR(inode)) {
10484                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10485                 if (ret) {
10486                         btrfs_add_delayed_iput(inode);
10487                         goto out;
10488                 }
10489                 clear_nlink(inode);
10490                 /* One for the block groups ref */
10491                 spin_lock(&block_group->lock);
10492                 if (block_group->iref) {
10493                         block_group->iref = 0;
10494                         block_group->inode = NULL;
10495                         spin_unlock(&block_group->lock);
10496                         iput(inode);
10497                 } else {
10498                         spin_unlock(&block_group->lock);
10499                 }
10500                 /* One for our lookup ref */
10501                 btrfs_add_delayed_iput(inode);
10502         }
10503
10504         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10505         key.offset = block_group->key.objectid;
10506         key.type = 0;
10507
10508         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10509         if (ret < 0)
10510                 goto out;
10511         if (ret > 0)
10512                 btrfs_release_path(path);
10513         if (ret == 0) {
10514                 ret = btrfs_del_item(trans, tree_root, path);
10515                 if (ret)
10516                         goto out;
10517                 btrfs_release_path(path);
10518         }
10519
10520         spin_lock(&fs_info->block_group_cache_lock);
10521         rb_erase(&block_group->cache_node,
10522                  &fs_info->block_group_cache_tree);
10523         RB_CLEAR_NODE(&block_group->cache_node);
10524
10525         if (fs_info->first_logical_byte == block_group->key.objectid)
10526                 fs_info->first_logical_byte = (u64)-1;
10527         spin_unlock(&fs_info->block_group_cache_lock);
10528
10529         down_write(&block_group->space_info->groups_sem);
10530         /*
10531          * we must use list_del_init so people can check to see if they
10532          * are still on the list after taking the semaphore
10533          */
10534         list_del_init(&block_group->list);
10535         if (list_empty(&block_group->space_info->block_groups[index])) {
10536                 kobj = block_group->space_info->block_group_kobjs[index];
10537                 block_group->space_info->block_group_kobjs[index] = NULL;
10538                 clear_avail_alloc_bits(fs_info, block_group->flags);
10539         }
10540         up_write(&block_group->space_info->groups_sem);
10541         if (kobj) {
10542                 kobject_del(kobj);
10543                 kobject_put(kobj);
10544         }
10545
10546         if (block_group->has_caching_ctl)
10547                 caching_ctl = get_caching_control(block_group);
10548         if (block_group->cached == BTRFS_CACHE_STARTED)
10549                 wait_block_group_cache_done(block_group);
10550         if (block_group->has_caching_ctl) {
10551                 down_write(&fs_info->commit_root_sem);
10552                 if (!caching_ctl) {
10553                         struct btrfs_caching_control *ctl;
10554
10555                         list_for_each_entry(ctl,
10556                                     &fs_info->caching_block_groups, list)
10557                                 if (ctl->block_group == block_group) {
10558                                         caching_ctl = ctl;
10559                                         refcount_inc(&caching_ctl->count);
10560                                         break;
10561                                 }
10562                 }
10563                 if (caching_ctl)
10564                         list_del_init(&caching_ctl->list);
10565                 up_write(&fs_info->commit_root_sem);
10566                 if (caching_ctl) {
10567                         /* Once for the caching bgs list and once for us. */
10568                         put_caching_control(caching_ctl);
10569                         put_caching_control(caching_ctl);
10570                 }
10571         }
10572
10573         spin_lock(&trans->transaction->dirty_bgs_lock);
10574         if (!list_empty(&block_group->dirty_list)) {
10575                 WARN_ON(1);
10576         }
10577         if (!list_empty(&block_group->io_list)) {
10578                 WARN_ON(1);
10579         }
10580         spin_unlock(&trans->transaction->dirty_bgs_lock);
10581         btrfs_remove_free_space_cache(block_group);
10582
10583         spin_lock(&block_group->space_info->lock);
10584         list_del_init(&block_group->ro_list);
10585
10586         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
10587                 WARN_ON(block_group->space_info->total_bytes
10588                         < block_group->key.offset);
10589                 WARN_ON(block_group->space_info->bytes_readonly
10590                         < block_group->key.offset);
10591                 WARN_ON(block_group->space_info->disk_total
10592                         < block_group->key.offset * factor);
10593         }
10594         block_group->space_info->total_bytes -= block_group->key.offset;
10595         block_group->space_info->bytes_readonly -= block_group->key.offset;
10596         block_group->space_info->disk_total -= block_group->key.offset * factor;
10597
10598         spin_unlock(&block_group->space_info->lock);
10599
10600         memcpy(&key, &block_group->key, sizeof(key));
10601
10602         mutex_lock(&fs_info->chunk_mutex);
10603         if (!list_empty(&em->list)) {
10604                 /* We're in the transaction->pending_chunks list. */
10605                 free_extent_map(em);
10606         }
10607         spin_lock(&block_group->lock);
10608         block_group->removed = 1;
10609         /*
10610          * At this point trimming can't start on this block group, because we
10611          * removed the block group from the tree fs_info->block_group_cache_tree
10612          * so no one can't find it anymore and even if someone already got this
10613          * block group before we removed it from the rbtree, they have already
10614          * incremented block_group->trimming - if they didn't, they won't find
10615          * any free space entries because we already removed them all when we
10616          * called btrfs_remove_free_space_cache().
10617          *
10618          * And we must not remove the extent map from the fs_info->mapping_tree
10619          * to prevent the same logical address range and physical device space
10620          * ranges from being reused for a new block group. This is because our
10621          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10622          * completely transactionless, so while it is trimming a range the
10623          * currently running transaction might finish and a new one start,
10624          * allowing for new block groups to be created that can reuse the same
10625          * physical device locations unless we take this special care.
10626          *
10627          * There may also be an implicit trim operation if the file system
10628          * is mounted with -odiscard. The same protections must remain
10629          * in place until the extents have been discarded completely when
10630          * the transaction commit has completed.
10631          */
10632         remove_em = (atomic_read(&block_group->trimming) == 0);
10633         /*
10634          * Make sure a trimmer task always sees the em in the pinned_chunks list
10635          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10636          * before checking block_group->removed).
10637          */
10638         if (!remove_em) {
10639                 /*
10640                  * Our em might be in trans->transaction->pending_chunks which
10641                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10642                  * and so is the fs_info->pinned_chunks list.
10643                  *
10644                  * So at this point we must be holding the chunk_mutex to avoid
10645                  * any races with chunk allocation (more specifically at
10646                  * volumes.c:contains_pending_extent()), to ensure it always
10647                  * sees the em, either in the pending_chunks list or in the
10648                  * pinned_chunks list.
10649                  */
10650                 list_move_tail(&em->list, &fs_info->pinned_chunks);
10651         }
10652         spin_unlock(&block_group->lock);
10653
10654         if (remove_em) {
10655                 struct extent_map_tree *em_tree;
10656
10657                 em_tree = &fs_info->mapping_tree.map_tree;
10658                 write_lock(&em_tree->lock);
10659                 /*
10660                  * The em might be in the pending_chunks list, so make sure the
10661                  * chunk mutex is locked, since remove_extent_mapping() will
10662                  * delete us from that list.
10663                  */
10664                 remove_extent_mapping(em_tree, em);
10665                 write_unlock(&em_tree->lock);
10666                 /* once for the tree */
10667                 free_extent_map(em);
10668         }
10669
10670         mutex_unlock(&fs_info->chunk_mutex);
10671
10672         ret = remove_block_group_free_space(trans, block_group);
10673         if (ret)
10674                 goto out;
10675
10676         btrfs_put_block_group(block_group);
10677         btrfs_put_block_group(block_group);
10678
10679         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10680         if (ret > 0)
10681                 ret = -EIO;
10682         if (ret < 0)
10683                 goto out;
10684
10685         ret = btrfs_del_item(trans, root, path);
10686 out:
10687         btrfs_free_path(path);
10688         return ret;
10689 }
10690
10691 struct btrfs_trans_handle *
10692 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10693                                      const u64 chunk_offset)
10694 {
10695         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10696         struct extent_map *em;
10697         struct map_lookup *map;
10698         unsigned int num_items;
10699
10700         read_lock(&em_tree->lock);
10701         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10702         read_unlock(&em_tree->lock);
10703         ASSERT(em && em->start == chunk_offset);
10704
10705         /*
10706          * We need to reserve 3 + N units from the metadata space info in order
10707          * to remove a block group (done at btrfs_remove_chunk() and at
10708          * btrfs_remove_block_group()), which are used for:
10709          *
10710          * 1 unit for adding the free space inode's orphan (located in the tree
10711          * of tree roots).
10712          * 1 unit for deleting the block group item (located in the extent
10713          * tree).
10714          * 1 unit for deleting the free space item (located in tree of tree
10715          * roots).
10716          * N units for deleting N device extent items corresponding to each
10717          * stripe (located in the device tree).
10718          *
10719          * In order to remove a block group we also need to reserve units in the
10720          * system space info in order to update the chunk tree (update one or
10721          * more device items and remove one chunk item), but this is done at
10722          * btrfs_remove_chunk() through a call to check_system_chunk().
10723          */
10724         map = em->map_lookup;
10725         num_items = 3 + map->num_stripes;
10726         free_extent_map(em);
10727
10728         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10729                                                            num_items, 1);
10730 }
10731
10732 /*
10733  * Process the unused_bgs list and remove any that don't have any allocated
10734  * space inside of them.
10735  */
10736 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10737 {
10738         struct btrfs_block_group_cache *block_group;
10739         struct btrfs_space_info *space_info;
10740         struct btrfs_trans_handle *trans;
10741         int ret = 0;
10742
10743         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10744                 return;
10745
10746         spin_lock(&fs_info->unused_bgs_lock);
10747         while (!list_empty(&fs_info->unused_bgs)) {
10748                 u64 start, end;
10749                 int trimming;
10750
10751                 block_group = list_first_entry(&fs_info->unused_bgs,
10752                                                struct btrfs_block_group_cache,
10753                                                bg_list);
10754                 list_del_init(&block_group->bg_list);
10755
10756                 space_info = block_group->space_info;
10757
10758                 if (ret || btrfs_mixed_space_info(space_info)) {
10759                         btrfs_put_block_group(block_group);
10760                         continue;
10761                 }
10762                 spin_unlock(&fs_info->unused_bgs_lock);
10763
10764                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10765
10766                 /* Don't want to race with allocators so take the groups_sem */
10767                 down_write(&space_info->groups_sem);
10768                 spin_lock(&block_group->lock);
10769                 if (block_group->reserved || block_group->pinned ||
10770                     btrfs_block_group_used(&block_group->item) ||
10771                     block_group->ro ||
10772                     list_is_singular(&block_group->list)) {
10773                         /*
10774                          * We want to bail if we made new allocations or have
10775                          * outstanding allocations in this block group.  We do
10776                          * the ro check in case balance is currently acting on
10777                          * this block group.
10778                          */
10779                         trace_btrfs_skip_unused_block_group(block_group);
10780                         spin_unlock(&block_group->lock);
10781                         up_write(&space_info->groups_sem);
10782                         goto next;
10783                 }
10784                 spin_unlock(&block_group->lock);
10785
10786                 /* We don't want to force the issue, only flip if it's ok. */
10787                 ret = inc_block_group_ro(block_group, 0);
10788                 up_write(&space_info->groups_sem);
10789                 if (ret < 0) {
10790                         ret = 0;
10791                         goto next;
10792                 }
10793
10794                 /*
10795                  * Want to do this before we do anything else so we can recover
10796                  * properly if we fail to join the transaction.
10797                  */
10798                 trans = btrfs_start_trans_remove_block_group(fs_info,
10799                                                      block_group->key.objectid);
10800                 if (IS_ERR(trans)) {
10801                         btrfs_dec_block_group_ro(block_group);
10802                         ret = PTR_ERR(trans);
10803                         goto next;
10804                 }
10805
10806                 /*
10807                  * We could have pending pinned extents for this block group,
10808                  * just delete them, we don't care about them anymore.
10809                  */
10810                 start = block_group->key.objectid;
10811                 end = start + block_group->key.offset - 1;
10812                 /*
10813                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10814                  * btrfs_finish_extent_commit(). If we are at transaction N,
10815                  * another task might be running finish_extent_commit() for the
10816                  * previous transaction N - 1, and have seen a range belonging
10817                  * to the block group in freed_extents[] before we were able to
10818                  * clear the whole block group range from freed_extents[]. This
10819                  * means that task can lookup for the block group after we
10820                  * unpinned it from freed_extents[] and removed it, leading to
10821                  * a BUG_ON() at btrfs_unpin_extent_range().
10822                  */
10823                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10824                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10825                                   EXTENT_DIRTY);
10826                 if (ret) {
10827                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10828                         btrfs_dec_block_group_ro(block_group);
10829                         goto end_trans;
10830                 }
10831                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10832                                   EXTENT_DIRTY);
10833                 if (ret) {
10834                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10835                         btrfs_dec_block_group_ro(block_group);
10836                         goto end_trans;
10837                 }
10838                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10839
10840                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10841                 spin_lock(&space_info->lock);
10842                 spin_lock(&block_group->lock);
10843
10844                 update_bytes_pinned(space_info, -block_group->pinned);
10845                 space_info->bytes_readonly += block_group->pinned;
10846                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
10847                                    -block_group->pinned,
10848                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
10849                 block_group->pinned = 0;
10850
10851                 spin_unlock(&block_group->lock);
10852                 spin_unlock(&space_info->lock);
10853
10854                 /* DISCARD can flip during remount */
10855                 trimming = btrfs_test_opt(fs_info, DISCARD);
10856
10857                 /* Implicit trim during transaction commit. */
10858                 if (trimming)
10859                         btrfs_get_block_group_trimming(block_group);
10860
10861                 /*
10862                  * Btrfs_remove_chunk will abort the transaction if things go
10863                  * horribly wrong.
10864                  */
10865                 ret = btrfs_remove_chunk(trans, block_group->key.objectid);
10866
10867                 if (ret) {
10868                         if (trimming)
10869                                 btrfs_put_block_group_trimming(block_group);
10870                         goto end_trans;
10871                 }
10872
10873                 /*
10874                  * If we're not mounted with -odiscard, we can just forget
10875                  * about this block group. Otherwise we'll need to wait
10876                  * until transaction commit to do the actual discard.
10877                  */
10878                 if (trimming) {
10879                         spin_lock(&fs_info->unused_bgs_lock);
10880                         /*
10881                          * A concurrent scrub might have added us to the list
10882                          * fs_info->unused_bgs, so use a list_move operation
10883                          * to add the block group to the deleted_bgs list.
10884                          */
10885                         list_move(&block_group->bg_list,
10886                                   &trans->transaction->deleted_bgs);
10887                         spin_unlock(&fs_info->unused_bgs_lock);
10888                         btrfs_get_block_group(block_group);
10889                 }
10890 end_trans:
10891                 btrfs_end_transaction(trans);
10892 next:
10893                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10894                 btrfs_put_block_group(block_group);
10895                 spin_lock(&fs_info->unused_bgs_lock);
10896         }
10897         spin_unlock(&fs_info->unused_bgs_lock);
10898 }
10899
10900 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10901 {
10902         struct btrfs_super_block *disk_super;
10903         u64 features;
10904         u64 flags;
10905         int mixed = 0;
10906         int ret;
10907
10908         disk_super = fs_info->super_copy;
10909         if (!btrfs_super_root(disk_super))
10910                 return -EINVAL;
10911
10912         features = btrfs_super_incompat_flags(disk_super);
10913         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10914                 mixed = 1;
10915
10916         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10917         ret = create_space_info(fs_info, flags);
10918         if (ret)
10919                 goto out;
10920
10921         if (mixed) {
10922                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10923                 ret = create_space_info(fs_info, flags);
10924         } else {
10925                 flags = BTRFS_BLOCK_GROUP_METADATA;
10926                 ret = create_space_info(fs_info, flags);
10927                 if (ret)
10928                         goto out;
10929
10930                 flags = BTRFS_BLOCK_GROUP_DATA;
10931                 ret = create_space_info(fs_info, flags);
10932         }
10933 out:
10934         return ret;
10935 }
10936
10937 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
10938                                    u64 start, u64 end)
10939 {
10940         return unpin_extent_range(fs_info, start, end, false);
10941 }
10942
10943 /*
10944  * It used to be that old block groups would be left around forever.
10945  * Iterating over them would be enough to trim unused space.  Since we
10946  * now automatically remove them, we also need to iterate over unallocated
10947  * space.
10948  *
10949  * We don't want a transaction for this since the discard may take a
10950  * substantial amount of time.  We don't require that a transaction be
10951  * running, but we do need to take a running transaction into account
10952  * to ensure that we're not discarding chunks that were released or
10953  * allocated in the current transaction.
10954  *
10955  * Holding the chunks lock will prevent other threads from allocating
10956  * or releasing chunks, but it won't prevent a running transaction
10957  * from committing and releasing the memory that the pending chunks
10958  * list head uses.  For that, we need to take a reference to the
10959  * transaction and hold the commit root sem.  We only need to hold
10960  * it while performing the free space search since we have already
10961  * held back allocations.
10962  */
10963 static int btrfs_trim_free_extents(struct btrfs_device *device,
10964                                    u64 minlen, u64 *trimmed)
10965 {
10966         u64 start = 0, len = 0;
10967         int ret;
10968
10969         *trimmed = 0;
10970
10971         /* Discard not supported = nothing to do. */
10972         if (!blk_queue_discard(bdev_get_queue(device->bdev)))
10973                 return 0;
10974
10975         /* Not writeable = nothing to do. */
10976         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
10977                 return 0;
10978
10979         /* No free space = nothing to do. */
10980         if (device->total_bytes <= device->bytes_used)
10981                 return 0;
10982
10983         ret = 0;
10984
10985         while (1) {
10986                 struct btrfs_fs_info *fs_info = device->fs_info;
10987                 struct btrfs_transaction *trans;
10988                 u64 bytes;
10989
10990                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10991                 if (ret)
10992                         break;
10993
10994                 ret = down_read_killable(&fs_info->commit_root_sem);
10995                 if (ret) {
10996                         mutex_unlock(&fs_info->chunk_mutex);
10997                         break;
10998                 }
10999
11000                 spin_lock(&fs_info->trans_lock);
11001                 trans = fs_info->running_transaction;
11002                 if (trans)
11003                         refcount_inc(&trans->use_count);
11004                 spin_unlock(&fs_info->trans_lock);
11005
11006                 if (!trans)
11007                         up_read(&fs_info->commit_root_sem);
11008
11009                 ret = find_free_dev_extent_start(trans, device, minlen, start,
11010                                                  &start, &len);
11011                 if (trans) {
11012                         up_read(&fs_info->commit_root_sem);
11013                         btrfs_put_transaction(trans);
11014                 }
11015
11016                 if (ret) {
11017                         mutex_unlock(&fs_info->chunk_mutex);
11018                         if (ret == -ENOSPC)
11019                                 ret = 0;
11020                         break;
11021                 }
11022
11023                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
11024                 mutex_unlock(&fs_info->chunk_mutex);
11025
11026                 if (ret)
11027                         break;
11028
11029                 start += len;
11030                 *trimmed += bytes;
11031
11032                 if (fatal_signal_pending(current)) {
11033                         ret = -ERESTARTSYS;
11034                         break;
11035                 }
11036
11037                 cond_resched();
11038         }
11039
11040         return ret;
11041 }
11042
11043 /*
11044  * Trim the whole filesystem by:
11045  * 1) trimming the free space in each block group
11046  * 2) trimming the unallocated space on each device
11047  *
11048  * This will also continue trimming even if a block group or device encounters
11049  * an error.  The return value will be the last error, or 0 if nothing bad
11050  * happens.
11051  */
11052 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
11053 {
11054         struct btrfs_block_group_cache *cache = NULL;
11055         struct btrfs_device *device;
11056         struct list_head *devices;
11057         u64 group_trimmed;
11058         u64 start;
11059         u64 end;
11060         u64 trimmed = 0;
11061         u64 bg_failed = 0;
11062         u64 dev_failed = 0;
11063         int bg_ret = 0;
11064         int dev_ret = 0;
11065         int ret = 0;
11066
11067         cache = btrfs_lookup_first_block_group(fs_info, range->start);
11068         for (; cache; cache = next_block_group(fs_info, cache)) {
11069                 if (cache->key.objectid >= (range->start + range->len)) {
11070                         btrfs_put_block_group(cache);
11071                         break;
11072                 }
11073
11074                 start = max(range->start, cache->key.objectid);
11075                 end = min(range->start + range->len,
11076                                 cache->key.objectid + cache->key.offset);
11077
11078                 if (end - start >= range->minlen) {
11079                         if (!block_group_cache_done(cache)) {
11080                                 ret = cache_block_group(cache, 0);
11081                                 if (ret) {
11082                                         bg_failed++;
11083                                         bg_ret = ret;
11084                                         continue;
11085                                 }
11086                                 ret = wait_block_group_cache_done(cache);
11087                                 if (ret) {
11088                                         bg_failed++;
11089                                         bg_ret = ret;
11090                                         continue;
11091                                 }
11092                         }
11093                         ret = btrfs_trim_block_group(cache,
11094                                                      &group_trimmed,
11095                                                      start,
11096                                                      end,
11097                                                      range->minlen);
11098
11099                         trimmed += group_trimmed;
11100                         if (ret) {
11101                                 bg_failed++;
11102                                 bg_ret = ret;
11103                                 continue;
11104                         }
11105                 }
11106         }
11107
11108         if (bg_failed)
11109                 btrfs_warn(fs_info,
11110                         "failed to trim %llu block group(s), last error %d",
11111                         bg_failed, bg_ret);
11112         mutex_lock(&fs_info->fs_devices->device_list_mutex);
11113         devices = &fs_info->fs_devices->devices;
11114         list_for_each_entry(device, devices, dev_list) {
11115                 ret = btrfs_trim_free_extents(device, range->minlen,
11116                                               &group_trimmed);
11117                 if (ret) {
11118                         dev_failed++;
11119                         dev_ret = ret;
11120                         break;
11121                 }
11122
11123                 trimmed += group_trimmed;
11124         }
11125         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
11126
11127         if (dev_failed)
11128                 btrfs_warn(fs_info,
11129                         "failed to trim %llu device(s), last error %d",
11130                         dev_failed, dev_ret);
11131         range->len = trimmed;
11132         if (bg_ret)
11133                 return bg_ret;
11134         return dev_ret;
11135 }
11136
11137 /*
11138  * btrfs_{start,end}_write_no_snapshotting() are similar to
11139  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11140  * data into the page cache through nocow before the subvolume is snapshoted,
11141  * but flush the data into disk after the snapshot creation, or to prevent
11142  * operations while snapshotting is ongoing and that cause the snapshot to be
11143  * inconsistent (writes followed by expanding truncates for example).
11144  */
11145 void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
11146 {
11147         percpu_counter_dec(&root->subv_writers->counter);
11148         cond_wake_up(&root->subv_writers->wait);
11149 }
11150
11151 int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
11152 {
11153         if (atomic_read(&root->will_be_snapshotted))
11154                 return 0;
11155
11156         percpu_counter_inc(&root->subv_writers->counter);
11157         /*
11158          * Make sure counter is updated before we check for snapshot creation.
11159          */
11160         smp_mb();
11161         if (atomic_read(&root->will_be_snapshotted)) {
11162                 btrfs_end_write_no_snapshotting(root);
11163                 return 0;
11164         }
11165         return 1;
11166 }
11167
11168 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11169 {
11170         while (true) {
11171                 int ret;
11172
11173                 ret = btrfs_start_write_no_snapshotting(root);
11174                 if (ret)
11175                         break;
11176                 wait_var_event(&root->will_be_snapshotted,
11177                                !atomic_read(&root->will_be_snapshotted));
11178         }
11179 }
11180
11181 void btrfs_mark_bg_unused(struct btrfs_block_group_cache *bg)
11182 {
11183         struct btrfs_fs_info *fs_info = bg->fs_info;
11184
11185         spin_lock(&fs_info->unused_bgs_lock);
11186         if (list_empty(&bg->bg_list)) {
11187                 btrfs_get_block_group(bg);
11188                 trace_btrfs_add_unused_block_group(bg);
11189                 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
11190         }
11191         spin_unlock(&fs_info->unused_bgs_lock);
11192 }