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