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