fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/percpu_counter.h>
  28 #include "hash.h"
  29 #include "tree-log.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "volumes.h"
  33 #include "raid56.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36 #include "math.h"
  37 #include "sysfs.h"
  38 #include "qgroup.h"
  39
  40 #undef SCRAMBLE_DELAYED_REFS
  41
  42 /*
  43  * control flags for do_chunk_alloc's force field
  44  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  45  * if we really need one.
  46  *
  47  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  48  * if we have very few chunks already allocated.  This is
  49  * used as part of the clustering code to help make sure
  50  * we have a good pool of storage to cluster in, without
  51  * filling the FS with empty chunks
  52  *
  53  * CHUNK_ALLOC_FORCE means it must try to allocate one
  54  *
  55  */
  56 enum {
  57         CHUNK_ALLOC_NO_FORCE = 0,
  58         CHUNK_ALLOC_LIMITED = 1,
  59         CHUNK_ALLOC_FORCE = 2,
  60 };
  61
  62 /*
  63  * Control how reservations are dealt with.
  64  *
  65  * RESERVE_FREE - freeing a reservation.
  66  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  67  *   ENOSPC accounting
  68  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  69  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  70  */
  71 enum {
  72         RESERVE_FREE = 0,
  73         RESERVE_ALLOC = 1,
  74         RESERVE_ALLOC_NO_ACCOUNT = 2,
  75 };
  76
  77 static int update_block_group(struct btrfs_root *root,
  78                               u64 bytenr, u64 num_bytes, int alloc);
  79 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  80                                 struct btrfs_root *root,
  81                                 u64 bytenr, u64 num_bytes, u64 parent,
  82                                 u64 root_objectid, u64 owner_objectid,
  83                                 u64 owner_offset, int refs_to_drop,
  84                                 struct btrfs_delayed_extent_op *extra_op,
  85                                 int no_quota);
  86 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  87                                     struct extent_buffer *leaf,
  88                                     struct btrfs_extent_item *ei);
  89 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  90                                       struct btrfs_root *root,
  91                                       u64 parent, u64 root_objectid,
  92                                       u64 flags, u64 owner, u64 offset,
  93                                       struct btrfs_key *ins, int ref_mod);
  94 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  95                                      struct btrfs_root *root,
  96                                      u64 parent, u64 root_objectid,
  97                                      u64 flags, struct btrfs_disk_key *key,
  98                                      int level, struct btrfs_key *ins,
  99                                      int no_quota);
 100 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 101                           struct btrfs_root *extent_root, u64 flags,
 102                           int force);
 103 static int find_next_key(struct btrfs_path *path, int level,
 104                          struct btrfs_key *key);
 105 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 106                             int dump_block_groups);
 107 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 108                                        u64 num_bytes, int reserve,
 109                                        int delalloc);
 110 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 111                                u64 num_bytes);
 112 int btrfs_pin_extent(struct btrfs_root *root,
 113                      u64 bytenr, u64 num_bytes, int reserved);
 114
 115 static noinline int
 116 block_group_cache_done(struct btrfs_block_group_cache *cache)
 117 {
 118         smp_mb();
 119         return cache->cached == BTRFS_CACHE_FINISHED ||
 120                 cache->cached == BTRFS_CACHE_ERROR;
 121 }
 122
 123 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 124 {
 125         return (cache->flags & bits) == bits;
 126 }
 127
 128 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 129 {
 130         atomic_inc(&cache->count);
 131 }
 132
 133 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 134 {
 135         if (atomic_dec_and_test(&cache->count)) {
 136                 WARN_ON(cache->pinned > 0);
 137                 WARN_ON(cache->reserved > 0);
 138                 kfree(cache->free_space_ctl);
 139                 kfree(cache);
 140         }
 141 }
 142
 143 /*
 144  * this adds the block group to the fs_info rb tree for the block group
 145  * cache
 146  */
 147 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 148                                 struct btrfs_block_group_cache *block_group)
 149 {
 150         struct rb_node **p;
 151         struct rb_node *parent = NULL;
 152         struct btrfs_block_group_cache *cache;
 153
 154         spin_lock(&info->block_group_cache_lock);
 155         p = &info->block_group_cache_tree.rb_node;
 156
 157         while (*p) {
 158                 parent = *p;
 159                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 160                                  cache_node);
 161                 if (block_group->key.objectid < cache->key.objectid) {
 162                         p = &(*p)->rb_left;
 163                 } else if (block_group->key.objectid > cache->key.objectid) {
 164                         p = &(*p)->rb_right;
 165                 } else {
 166                         spin_unlock(&info->block_group_cache_lock);
 167                         return -EEXIST;
 168                 }
 169         }
 170
 171         rb_link_node(&block_group->cache_node, parent, p);
 172         rb_insert_color(&block_group->cache_node,
 173                         &info->block_group_cache_tree);
 174
 175         if (info->first_logical_byte > block_group->key.objectid)
 176                 info->first_logical_byte = block_group->key.objectid;
 177
 178         spin_unlock(&info->block_group_cache_lock);
 179
 180         return 0;
 181 }
 182
 183 /*
 184  * This will return the block group at or after bytenr if contains is 0, else
 185  * it will return the block group that contains the bytenr
 186  */
 187 static struct btrfs_block_group_cache *
 188 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 189                               int contains)
 190 {
 191         struct btrfs_block_group_cache *cache, *ret = NULL;
 192         struct rb_node *n;
 193         u64 end, start;
 194
 195         spin_lock(&info->block_group_cache_lock);
 196         n = info->block_group_cache_tree.rb_node;
 197
 198         while (n) {
 199                 cache = rb_entry(n, struct btrfs_block_group_cache,
 200                                  cache_node);
 201                 end = cache->key.objectid + cache->key.offset - 1;
 202                 start = cache->key.objectid;
 203
 204                 if (bytenr < start) {
 205                         if (!contains && (!ret || start < ret->key.objectid))
 206                                 ret = cache;
 207                         n = n->rb_left;
 208                 } else if (bytenr > start) {
 209                         if (contains && bytenr <= end) {
 210                                 ret = cache;
 211                                 break;
 212                         }
 213                         n = n->rb_right;
 214                 } else {
 215                         ret = cache;
 216                         break;
 217                 }
 218         }
 219         if (ret) {
 220                 btrfs_get_block_group(ret);
 221                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 222                         info->first_logical_byte = ret->key.objectid;
 223         }
 224         spin_unlock(&info->block_group_cache_lock);
 225
 226         return ret;
 227 }
 228
 229 static int add_excluded_extent(struct btrfs_root *root,
 230                                u64 start, u64 num_bytes)
 231 {
 232         u64 end = start + num_bytes - 1;
 233         set_extent_bits(&root->fs_info->freed_extents[0],
 234                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 235         set_extent_bits(&root->fs_info->freed_extents[1],
 236                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 237         return 0;
 238 }
 239
 240 static void free_excluded_extents(struct btrfs_root *root,
 241                                   struct btrfs_block_group_cache *cache)
 242 {
 243         u64 start, end;
 244
 245         start = cache->key.objectid;
 246         end = start + cache->key.offset - 1;
 247
 248         clear_extent_bits(&root->fs_info->freed_extents[0],
 249                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 250         clear_extent_bits(&root->fs_info->freed_extents[1],
 251                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 252 }
 253
 254 static int exclude_super_stripes(struct btrfs_root *root,
 255                                  struct btrfs_block_group_cache *cache)
 256 {
 257         u64 bytenr;
 258         u64 *logical;
 259         int stripe_len;
 260         int i, nr, ret;
 261
 262         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 263                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 264                 cache->bytes_super += stripe_len;
 265                 ret = add_excluded_extent(root, cache->key.objectid,
 266                                           stripe_len);
 267                 if (ret)
 268                         return ret;
 269         }
 270
 271         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 272                 bytenr = btrfs_sb_offset(i);
 273                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 274                                        cache->key.objectid, bytenr,
 275                                        0, &logical, &nr, &stripe_len);
 276                 if (ret)
 277                         return ret;
 278
 279                 while (nr--) {
 280                         u64 start, len;
 281
 282                         if (logical[nr] > cache->key.objectid +
 283                             cache->key.offset)
 284                                 continue;
 285
 286                         if (logical[nr] + stripe_len <= cache->key.objectid)
 287                                 continue;
 288
 289                         start = logical[nr];
 290                         if (start < cache->key.objectid) {
 291                                 start = cache->key.objectid;
 292                                 len = (logical[nr] + stripe_len) - start;
 293                         } else {
 294                                 len = min_t(u64, stripe_len,
 295                                             cache->key.objectid +
 296                                             cache->key.offset - start);
 297                         }
 298
 299                         cache->bytes_super += len;
 300                         ret = add_excluded_extent(root, start, len);
 301                         if (ret) {
 302                                 kfree(logical);
 303                                 return ret;
 304                         }
 305                 }
 306
 307                 kfree(logical);
 308         }
 309         return 0;
 310 }
 311
 312 static struct btrfs_caching_control *
 313 get_caching_control(struct btrfs_block_group_cache *cache)
 314 {
 315         struct btrfs_caching_control *ctl;
 316
 317         spin_lock(&cache->lock);
 318         if (cache->cached != BTRFS_CACHE_STARTED) {
 319                 spin_unlock(&cache->lock);
 320                 return NULL;
 321         }
 322
 323         /* We're loading it the fast way, so we don't have a caching_ctl. */
 324         if (!cache->caching_ctl) {
 325                 spin_unlock(&cache->lock);
 326                 return NULL;
 327         }
 328
 329         ctl = cache->caching_ctl;
 330         atomic_inc(&ctl->count);
 331         spin_unlock(&cache->lock);
 332         return ctl;
 333 }
 334
 335 static void put_caching_control(struct btrfs_caching_control *ctl)
 336 {
 337         if (atomic_dec_and_test(&ctl->count))
 338                 kfree(ctl);
 339 }
 340
 341 /*
 342  * this is only called by cache_block_group, since we could have freed extents
 343  * we need to check the pinned_extents for any extents that can't be used yet
 344  * since their free space will be released as soon as the transaction commits.
 345  */
 346 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 347                               struct btrfs_fs_info *info, u64 start, u64 end)
 348 {
 349         u64 extent_start, extent_end, size, total_added = 0;
 350         int ret;
 351
 352         while (start < end) {
 353                 ret = find_first_extent_bit(info->pinned_extents, start,
 354                                             &extent_start, &extent_end,
 355                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 356                                             NULL);
 357                 if (ret)
 358                         break;
 359
 360                 if (extent_start <= start) {
 361                         start = extent_end + 1;
 362                 } else if (extent_start > start && extent_start < end) {
 363                         size = extent_start - start;
 364                         total_added += size;
 365                         ret = btrfs_add_free_space(block_group, start,
 366                                                    size);
 367                         BUG_ON(ret); /* -ENOMEM or logic error */
 368                         start = extent_end + 1;
 369                 } else {
 370                         break;
 371                 }
 372         }
 373
 374         if (start < end) {
 375                 size = end - start;
 376                 total_added += size;
 377                 ret = btrfs_add_free_space(block_group, start, size);
 378                 BUG_ON(ret); /* -ENOMEM or logic error */
 379         }
 380
 381         return total_added;
 382 }
 383
 384 static noinline void caching_thread(struct btrfs_work *work)
 385 {
 386         struct btrfs_block_group_cache *block_group;
 387         struct btrfs_fs_info *fs_info;
 388         struct btrfs_caching_control *caching_ctl;
 389         struct btrfs_root *extent_root;
 390         struct btrfs_path *path;
 391         struct extent_buffer *leaf;
 392         struct btrfs_key key;
 393         u64 total_found = 0;
 394         u64 last = 0;
 395         u32 nritems;
 396         int ret = -ENOMEM;
 397
 398         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 399         block_group = caching_ctl->block_group;
 400         fs_info = block_group->fs_info;
 401         extent_root = fs_info->extent_root;
 402
 403         path = btrfs_alloc_path();
 404         if (!path)
 405                 goto out;
 406
 407         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 408
 409         /*
 410          * We don't want to deadlock with somebody trying to allocate a new
 411          * extent for the extent root while also trying to search the extent
 412          * root to add free space.  So we skip locking and search the commit
 413          * root, since its read-only
 414          */
 415         path->skip_locking = 1;
 416         path->search_commit_root = 1;
 417         path->reada = 1;
 418
 419         key.objectid = last;
 420         key.offset = 0;
 421         key.type = BTRFS_EXTENT_ITEM_KEY;
 422 again:
 423         mutex_lock(&caching_ctl->mutex);
 424         /* need to make sure the commit_root doesn't disappear */
 425         down_read(&fs_info->commit_root_sem);
 426
 427 next:
 428         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 429         if (ret < 0)
 430                 goto err;
 431
 432         leaf = path->nodes[0];
 433         nritems = btrfs_header_nritems(leaf);
 434
 435         while (1) {
 436                 if (btrfs_fs_closing(fs_info) > 1) {
 437                         last = (u64)-1;
 438                         break;
 439                 }
 440
 441                 if (path->slots[0] < nritems) {
 442                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 443                 } else {
 444                         ret = find_next_key(path, 0, &key);
 445                         if (ret)
 446                                 break;
 447
 448                         if (need_resched() ||
 449                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 450                                 caching_ctl->progress = last;
 451                                 btrfs_release_path(path);
 452                                 up_read(&fs_info->commit_root_sem);
 453                                 mutex_unlock(&caching_ctl->mutex);
 454                                 cond_resched();
 455                                 goto again;
 456                         }
 457
 458                         ret = btrfs_next_leaf(extent_root, path);
 459                         if (ret < 0)
 460                                 goto err;
 461                         if (ret)
 462                                 break;
 463                         leaf = path->nodes[0];
 464                         nritems = btrfs_header_nritems(leaf);
 465                         continue;
 466                 }
 467
 468                 if (key.objectid < last) {
 469                         key.objectid = last;
 470                         key.offset = 0;
 471                         key.type = BTRFS_EXTENT_ITEM_KEY;
 472
 473                         caching_ctl->progress = last;
 474                         btrfs_release_path(path);
 475                         goto next;
 476                 }
 477
 478                 if (key.objectid < block_group->key.objectid) {
 479                         path->slots[0]++;
 480                         continue;
 481                 }
 482
 483                 if (key.objectid >= block_group->key.objectid +
 484                     block_group->key.offset)
 485                         break;
 486
 487                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 488                     key.type == BTRFS_METADATA_ITEM_KEY) {
 489                         total_found += add_new_free_space(block_group,
 490                                                           fs_info, last,
 491                                                           key.objectid);
 492                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 493                                 last = key.objectid +
 494                                         fs_info->tree_root->leafsize;
 495                         else
 496                                 last = key.objectid + key.offset;
 497
 498                         if (total_found > (1024 * 1024 * 2)) {
 499                                 total_found = 0;
 500                                 wake_up(&caching_ctl->wait);
 501                         }
 502                 }
 503                 path->slots[0]++;
 504         }
 505         ret = 0;
 506
 507         total_found += add_new_free_space(block_group, fs_info, last,
 508                                           block_group->key.objectid +
 509                                           block_group->key.offset);
 510         caching_ctl->progress = (u64)-1;
 511
 512         spin_lock(&block_group->lock);
 513         block_group->caching_ctl = NULL;
 514         block_group->cached = BTRFS_CACHE_FINISHED;
 515         spin_unlock(&block_group->lock);
 516
 517 err:
 518         btrfs_free_path(path);
 519         up_read(&fs_info->commit_root_sem);
 520
 521         free_excluded_extents(extent_root, block_group);
 522
 523         mutex_unlock(&caching_ctl->mutex);
 524 out:
 525         if (ret) {
 526                 spin_lock(&block_group->lock);
 527                 block_group->caching_ctl = NULL;
 528                 block_group->cached = BTRFS_CACHE_ERROR;
 529                 spin_unlock(&block_group->lock);
 530         }
 531         wake_up(&caching_ctl->wait);
 532
 533         put_caching_control(caching_ctl);
 534         btrfs_put_block_group(block_group);
 535 }
 536
 537 static int cache_block_group(struct btrfs_block_group_cache *cache,
 538                              int load_cache_only)
 539 {
 540         DEFINE_WAIT(wait);
 541         struct btrfs_fs_info *fs_info = cache->fs_info;
 542         struct btrfs_caching_control *caching_ctl;
 543         int ret = 0;
 544
 545         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 546         if (!caching_ctl)
 547                 return -ENOMEM;
 548
 549         INIT_LIST_HEAD(&caching_ctl->list);
 550         mutex_init(&caching_ctl->mutex);
 551         init_waitqueue_head(&caching_ctl->wait);
 552         caching_ctl->block_group = cache;
 553         caching_ctl->progress = cache->key.objectid;
 554         atomic_set(&caching_ctl->count, 1);
 555         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 556                         caching_thread, NULL, NULL);
 557
 558         spin_lock(&cache->lock);
 559         /*
 560          * This should be a rare occasion, but this could happen I think in the
 561          * case where one thread starts to load the space cache info, and then
 562          * some other thread starts a transaction commit which tries to do an
 563          * allocation while the other thread is still loading the space cache
 564          * info.  The previous loop should have kept us from choosing this block
 565          * group, but if we've moved to the state where we will wait on caching
 566          * block groups we need to first check if we're doing a fast load here,
 567          * so we can wait for it to finish, otherwise we could end up allocating
 568          * from a block group who's cache gets evicted for one reason or
 569          * another.
 570          */
 571         while (cache->cached == BTRFS_CACHE_FAST) {
 572                 struct btrfs_caching_control *ctl;
 573
 574                 ctl = cache->caching_ctl;
 575                 atomic_inc(&ctl->count);
 576                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 577                 spin_unlock(&cache->lock);
 578
 579                 schedule();
 580
 581                 finish_wait(&ctl->wait, &wait);
 582                 put_caching_control(ctl);
 583                 spin_lock(&cache->lock);
 584         }
 585
 586         if (cache->cached != BTRFS_CACHE_NO) {
 587                 spin_unlock(&cache->lock);
 588                 kfree(caching_ctl);
 589                 return 0;
 590         }
 591         WARN_ON(cache->caching_ctl);
 592         cache->caching_ctl = caching_ctl;
 593         cache->cached = BTRFS_CACHE_FAST;
 594         spin_unlock(&cache->lock);
 595
 596         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 597                 ret = load_free_space_cache(fs_info, cache);
 598
 599                 spin_lock(&cache->lock);
 600                 if (ret == 1) {
 601                         cache->caching_ctl = NULL;
 602                         cache->cached = BTRFS_CACHE_FINISHED;
 603                         cache->last_byte_to_unpin = (u64)-1;
 604                 } else {
 605                         if (load_cache_only) {
 606                                 cache->caching_ctl = NULL;
 607                                 cache->cached = BTRFS_CACHE_NO;
 608                         } else {
 609                                 cache->cached = BTRFS_CACHE_STARTED;
 610                         }
 611                 }
 612                 spin_unlock(&cache->lock);
 613                 wake_up(&caching_ctl->wait);
 614                 if (ret == 1) {
 615                         put_caching_control(caching_ctl);
 616                         free_excluded_extents(fs_info->extent_root, cache);
 617                         return 0;
 618                 }
 619         } else {
 620                 /*
 621                  * We are not going to do the fast caching, set cached to the
 622                  * appropriate value and wakeup any waiters.
 623                  */
 624                 spin_lock(&cache->lock);
 625                 if (load_cache_only) {
 626                         cache->caching_ctl = NULL;
 627                         cache->cached = BTRFS_CACHE_NO;
 628                 } else {
 629                         cache->cached = BTRFS_CACHE_STARTED;
 630                 }
 631                 spin_unlock(&cache->lock);
 632                 wake_up(&caching_ctl->wait);
 633         }
 634
 635         if (load_cache_only) {
 636                 put_caching_control(caching_ctl);
 637                 return 0;
 638         }
 639
 640         down_write(&fs_info->commit_root_sem);
 641         atomic_inc(&caching_ctl->count);
 642         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 643         up_write(&fs_info->commit_root_sem);
 644
 645         btrfs_get_block_group(cache);
 646
 647         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 648
 649         return ret;
 650 }
 651
 652 /*
 653  * return the block group that starts at or after bytenr
 654  */
 655 static struct btrfs_block_group_cache *
 656 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 657 {
 658         struct btrfs_block_group_cache *cache;
 659
 660         cache = block_group_cache_tree_search(info, bytenr, 0);
 661
 662         return cache;
 663 }
 664
 665 /*
 666  * return the block group that contains the given bytenr
 667  */
 668 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 669                                                  struct btrfs_fs_info *info,
 670                                                  u64 bytenr)
 671 {
 672         struct btrfs_block_group_cache *cache;
 673
 674         cache = block_group_cache_tree_search(info, bytenr, 1);
 675
 676         return cache;
 677 }
 678
 679 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 680                                                   u64 flags)
 681 {
 682         struct list_head *head = &info->space_info;
 683         struct btrfs_space_info *found;
 684
 685         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 686
 687         rcu_read_lock();
 688         list_for_each_entry_rcu(found, head, list) {
 689                 if (found->flags & flags) {
 690                         rcu_read_unlock();
 691                         return found;
 692                 }
 693         }
 694         rcu_read_unlock();
 695         return NULL;
 696 }
 697
 698 /*
 699  * after adding space to the filesystem, we need to clear the full flags
 700  * on all the space infos.
 701  */
 702 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 703 {
 704         struct list_head *head = &info->space_info;
 705         struct btrfs_space_info *found;
 706
 707         rcu_read_lock();
 708         list_for_each_entry_rcu(found, head, list)
 709                 found->full = 0;
 710         rcu_read_unlock();
 711 }
 712
 713 /* simple helper to search for an existing extent at a given offset */
 714 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 715 {
 716         int ret;
 717         struct btrfs_key key;
 718         struct btrfs_path *path;
 719
 720         path = btrfs_alloc_path();
 721         if (!path)
 722                 return -ENOMEM;
 723
 724         key.objectid = start;
 725         key.offset = len;
 726         key.type = BTRFS_EXTENT_ITEM_KEY;
 727         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 728                                 0, 0);
 729         if (ret > 0) {
 730                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 731                 if (key.objectid == start &&
 732                     key.type == BTRFS_METADATA_ITEM_KEY)
 733                         ret = 0;
 734         }
 735         btrfs_free_path(path);
 736         return ret;
 737 }
 738
 739 /*
 740  * helper function to lookup reference count and flags of a tree block.
 741  *
 742  * the head node for delayed ref is used to store the sum of all the
 743  * reference count modifications queued up in the rbtree. the head
 744  * node may also store the extent flags to set. This way you can check
 745  * to see what the reference count and extent flags would be if all of
 746  * the delayed refs are not processed.
 747  */
 748 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 749                              struct btrfs_root *root, u64 bytenr,
 750                              u64 offset, int metadata, u64 *refs, u64 *flags)
 751 {
 752         struct btrfs_delayed_ref_head *head;
 753         struct btrfs_delayed_ref_root *delayed_refs;
 754         struct btrfs_path *path;
 755         struct btrfs_extent_item *ei;
 756         struct extent_buffer *leaf;
 757         struct btrfs_key key;
 758         u32 item_size;
 759         u64 num_refs;
 760         u64 extent_flags;
 761         int ret;
 762
 763         /*
 764          * If we don't have skinny metadata, don't bother doing anything
 765          * different
 766          */
 767         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 768                 offset = root->leafsize;
 769                 metadata = 0;
 770         }
 771
 772         path = btrfs_alloc_path();
 773         if (!path)
 774                 return -ENOMEM;
 775
 776         if (!trans) {
 777                 path->skip_locking = 1;
 778                 path->search_commit_root = 1;
 779         }
 780
 781 search_again:
 782         key.objectid = bytenr;
 783         key.offset = offset;
 784         if (metadata)
 785                 key.type = BTRFS_METADATA_ITEM_KEY;
 786         else
 787                 key.type = BTRFS_EXTENT_ITEM_KEY;
 788
 789 again:
 790         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 791                                 &key, path, 0, 0);
 792         if (ret < 0)
 793                 goto out_free;
 794
 795         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 796                 if (path->slots[0]) {
 797                         path->slots[0]--;
 798                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 799                                               path->slots[0]);
 800                         if (key.objectid == bytenr &&
 801                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 802                             key.offset == root->leafsize)
 803                                 ret = 0;
 804                 }
 805                 if (ret) {
 806                         key.objectid = bytenr;
 807                         key.type = BTRFS_EXTENT_ITEM_KEY;
 808                         key.offset = root->leafsize;
 809                         btrfs_release_path(path);
 810                         goto again;
 811                 }
 812         }
 813
 814         if (ret == 0) {
 815                 leaf = path->nodes[0];
 816                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 817                 if (item_size >= sizeof(*ei)) {
 818                         ei = btrfs_item_ptr(leaf, path->slots[0],
 819                                             struct btrfs_extent_item);
 820                         num_refs = btrfs_extent_refs(leaf, ei);
 821                         extent_flags = btrfs_extent_flags(leaf, ei);
 822                 } else {
 823 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 824                         struct btrfs_extent_item_v0 *ei0;
 825                         BUG_ON(item_size != sizeof(*ei0));
 826                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 827                                              struct btrfs_extent_item_v0);
 828                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 829                         /* FIXME: this isn't correct for data */
 830                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 831 #else
 832                         BUG();
 833 #endif
 834                 }
 835                 BUG_ON(num_refs == 0);
 836         } else {
 837                 num_refs = 0;
 838                 extent_flags = 0;
 839                 ret = 0;
 840         }
 841
 842         if (!trans)
 843                 goto out;
 844
 845         delayed_refs = &trans->transaction->delayed_refs;
 846         spin_lock(&delayed_refs->lock);
 847         head = btrfs_find_delayed_ref_head(trans, bytenr);
 848         if (head) {
 849                 if (!mutex_trylock(&head->mutex)) {
 850                         atomic_inc(&head->node.refs);
 851                         spin_unlock(&delayed_refs->lock);
 852
 853                         btrfs_release_path(path);
 854
 855                         /*
 856                          * Mutex was contended, block until it's released and try
 857                          * again
 858                          */
 859                         mutex_lock(&head->mutex);
 860                         mutex_unlock(&head->mutex);
 861                         btrfs_put_delayed_ref(&head->node);
 862                         goto search_again;
 863                 }
 864                 spin_lock(&head->lock);
 865                 if (head->extent_op && head->extent_op->update_flags)
 866                         extent_flags |= head->extent_op->flags_to_set;
 867                 else
 868                         BUG_ON(num_refs == 0);
 869
 870                 num_refs += head->node.ref_mod;
 871                 spin_unlock(&head->lock);
 872                 mutex_unlock(&head->mutex);
 873         }
 874         spin_unlock(&delayed_refs->lock);
 875 out:
 876         WARN_ON(num_refs == 0);
 877         if (refs)
 878                 *refs = num_refs;
 879         if (flags)
 880                 *flags = extent_flags;
 881 out_free:
 882         btrfs_free_path(path);
 883         return ret;
 884 }
 885
 886 /*
 887  * Back reference rules.  Back refs have three main goals:
 888  *
 889  * 1) differentiate between all holders of references to an extent so that
 890  *    when a reference is dropped we can make sure it was a valid reference
 891  *    before freeing the extent.
 892  *
 893  * 2) Provide enough information to quickly find the holders of an extent
 894  *    if we notice a given block is corrupted or bad.
 895  *
 896  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 897  *    maintenance.  This is actually the same as #2, but with a slightly
 898  *    different use case.
 899  *
 900  * There are two kinds of back refs. The implicit back refs is optimized
 901  * for pointers in non-shared tree blocks. For a given pointer in a block,
 902  * back refs of this kind provide information about the block's owner tree
 903  * and the pointer's key. These information allow us to find the block by
 904  * b-tree searching. The full back refs is for pointers in tree blocks not
 905  * referenced by their owner trees. The location of tree block is recorded
 906  * in the back refs. Actually the full back refs is generic, and can be
 907  * used in all cases the implicit back refs is used. The major shortcoming
 908  * of the full back refs is its overhead. Every time a tree block gets
 909  * COWed, we have to update back refs entry for all pointers in it.
 910  *
 911  * For a newly allocated tree block, we use implicit back refs for
 912  * pointers in it. This means most tree related operations only involve
 913  * implicit back refs. For a tree block created in old transaction, the
 914  * only way to drop a reference to it is COW it. So we can detect the
 915  * event that tree block loses its owner tree's reference and do the
 916  * back refs conversion.
 917  *
 918  * When a tree block is COW'd through a tree, there are four cases:
 919  *
 920  * The reference count of the block is one and the tree is the block's
 921  * owner tree. Nothing to do in this case.
 922  *
 923  * The reference count of the block is one and the tree is not the
 924  * block's owner tree. In this case, full back refs is used for pointers
 925  * in the block. Remove these full back refs, add implicit back refs for
 926  * every pointers in the new block.
 927  *
 928  * The reference count of the block is greater than one and the tree is
 929  * the block's owner tree. In this case, implicit back refs is used for
 930  * pointers in the block. Add full back refs for every pointers in the
 931  * block, increase lower level extents' reference counts. The original
 932  * implicit back refs are entailed to the new block.
 933  *
 934  * The reference count of the block is greater than one and the tree is
 935  * not the block's owner tree. Add implicit back refs for every pointer in
 936  * the new block, increase lower level extents' reference count.
 937  *
 938  * Back Reference Key composing:
 939  *
 940  * The key objectid corresponds to the first byte in the extent,
 941  * The key type is used to differentiate between types of back refs.
 942  * There are different meanings of the key offset for different types
 943  * of back refs.
 944  *
 945  * File extents can be referenced by:
 946  *
 947  * - multiple snapshots, subvolumes, or different generations in one subvol
 948  * - different files inside a single subvolume
 949  * - different offsets inside a file (bookend extents in file.c)
 950  *
 951  * The extent ref structure for the implicit back refs has fields for:
 952  *
 953  * - Objectid of the subvolume root
 954  * - objectid of the file holding the reference
 955  * - original offset in the file
 956  * - how many bookend extents
 957  *
 958  * The key offset for the implicit back refs is hash of the first
 959  * three fields.
 960  *
 961  * The extent ref structure for the full back refs has field for:
 962  *
 963  * - number of pointers in the tree leaf
 964  *
 965  * The key offset for the implicit back refs is the first byte of
 966  * the tree leaf
 967  *
 968  * When a file extent is allocated, The implicit back refs is used.
 969  * the fields are filled in:
 970  *
 971  *     (root_key.objectid, inode objectid, offset in file, 1)
 972  *
 973  * When a file extent is removed file truncation, we find the
 974  * corresponding implicit back refs and check the following fields:
 975  *
 976  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 977  *
 978  * Btree extents can be referenced by:
 979  *
 980  * - Different subvolumes
 981  *
 982  * Both the implicit back refs and the full back refs for tree blocks
 983  * only consist of key. The key offset for the implicit back refs is
 984  * objectid of block's owner tree. The key offset for the full back refs
 985  * is the first byte of parent block.
 986  *
 987  * When implicit back refs is used, information about the lowest key and
 988  * level of the tree block are required. These information are stored in
 989  * tree block info structure.
 990  */
 991
 992 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 993 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 994                                   struct btrfs_root *root,
 995                                   struct btrfs_path *path,
 996                                   u64 owner, u32 extra_size)
 997 {
 998         struct btrfs_extent_item *item;
 999         struct btrfs_extent_item_v0 *ei0;
1000         struct btrfs_extent_ref_v0 *ref0;
1001         struct btrfs_tree_block_info *bi;
1002         struct extent_buffer *leaf;
1003         struct btrfs_key key;
1004         struct btrfs_key found_key;
1005         u32 new_size = sizeof(*item);
1006         u64 refs;
1007         int ret;
1008
1009         leaf = path->nodes[0];
1010         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1011
1012         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1013         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1014                              struct btrfs_extent_item_v0);
1015         refs = btrfs_extent_refs_v0(leaf, ei0);
1016
1017         if (owner == (u64)-1) {
1018                 while (1) {
1019                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1020                                 ret = btrfs_next_leaf(root, path);
1021                                 if (ret < 0)
1022                                         return ret;
1023                                 BUG_ON(ret > 0); /* Corruption */
1024                                 leaf = path->nodes[0];
1025                         }
1026                         btrfs_item_key_to_cpu(leaf, &found_key,
1027                                               path->slots[0]);
1028                         BUG_ON(key.objectid != found_key.objectid);
1029                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1030                                 path->slots[0]++;
1031                                 continue;
1032                         }
1033                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1034                                               struct btrfs_extent_ref_v0);
1035                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1036                         break;
1037                 }
1038         }
1039         btrfs_release_path(path);
1040
1041         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1042                 new_size += sizeof(*bi);
1043
1044         new_size -= sizeof(*ei0);
1045         ret = btrfs_search_slot(trans, root, &key, path,
1046                                 new_size + extra_size, 1);
1047         if (ret < 0)
1048                 return ret;
1049         BUG_ON(ret); /* Corruption */
1050
1051         btrfs_extend_item(root, path, new_size);
1052
1053         leaf = path->nodes[0];
1054         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1055         btrfs_set_extent_refs(leaf, item, refs);
1056         /* FIXME: get real generation */
1057         btrfs_set_extent_generation(leaf, item, 0);
1058         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1059                 btrfs_set_extent_flags(leaf, item,
1060                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1061                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1062                 bi = (struct btrfs_tree_block_info *)(item + 1);
1063                 /* FIXME: get first key of the block */
1064                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1065                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1066         } else {
1067                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1068         }
1069         btrfs_mark_buffer_dirty(leaf);
1070         return 0;
1071 }
1072 #endif
1073
1074 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1075 {
1076         u32 high_crc = ~(u32)0;
1077         u32 low_crc = ~(u32)0;
1078         __le64 lenum;
1079
1080         lenum = cpu_to_le64(root_objectid);
1081         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1082         lenum = cpu_to_le64(owner);
1083         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1084         lenum = cpu_to_le64(offset);
1085         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1086
1087         return ((u64)high_crc << 31) ^ (u64)low_crc;
1088 }
1089
1090 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1091                                      struct btrfs_extent_data_ref *ref)
1092 {
1093         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1094                                     btrfs_extent_data_ref_objectid(leaf, ref),
1095                                     btrfs_extent_data_ref_offset(leaf, ref));
1096 }
1097
1098 static int match_extent_data_ref(struct extent_buffer *leaf,
1099                                  struct btrfs_extent_data_ref *ref,
1100                                  u64 root_objectid, u64 owner, u64 offset)
1101 {
1102         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1103             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1104             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1105                 return 0;
1106         return 1;
1107 }
1108
1109 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1110                                            struct btrfs_root *root,
1111                                            struct btrfs_path *path,
1112                                            u64 bytenr, u64 parent,
1113                                            u64 root_objectid,
1114                                            u64 owner, u64 offset)
1115 {
1116         struct btrfs_key key;
1117         struct btrfs_extent_data_ref *ref;
1118         struct extent_buffer *leaf;
1119         u32 nritems;
1120         int ret;
1121         int recow;
1122         int err = -ENOENT;
1123
1124         key.objectid = bytenr;
1125         if (parent) {
1126                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1127                 key.offset = parent;
1128         } else {
1129                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1130                 key.offset = hash_extent_data_ref(root_objectid,
1131                                                   owner, offset);
1132         }
1133 again:
1134         recow = 0;
1135         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1136         if (ret < 0) {
1137                 err = ret;
1138                 goto fail;
1139         }
1140
1141         if (parent) {
1142                 if (!ret)
1143                         return 0;
1144 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1145                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1146                 btrfs_release_path(path);
1147                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1148                 if (ret < 0) {
1149                         err = ret;
1150                         goto fail;
1151                 }
1152                 if (!ret)
1153                         return 0;
1154 #endif
1155                 goto fail;
1156         }
1157
1158         leaf = path->nodes[0];
1159         nritems = btrfs_header_nritems(leaf);
1160         while (1) {
1161                 if (path->slots[0] >= nritems) {
1162                         ret = btrfs_next_leaf(root, path);
1163                         if (ret < 0)
1164                                 err = ret;
1165                         if (ret)
1166                                 goto fail;
1167
1168                         leaf = path->nodes[0];
1169                         nritems = btrfs_header_nritems(leaf);
1170                         recow = 1;
1171                 }
1172
1173                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1174                 if (key.objectid != bytenr ||
1175                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1176                         goto fail;
1177
1178                 ref = btrfs_item_ptr(leaf, path->slots[0],
1179                                      struct btrfs_extent_data_ref);
1180
1181                 if (match_extent_data_ref(leaf, ref, root_objectid,
1182                                           owner, offset)) {
1183                         if (recow) {
1184                                 btrfs_release_path(path);
1185                                 goto again;
1186                         }
1187                         err = 0;
1188                         break;
1189                 }
1190                 path->slots[0]++;
1191         }
1192 fail:
1193         return err;
1194 }
1195
1196 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1197                                            struct btrfs_root *root,
1198                                            struct btrfs_path *path,
1199                                            u64 bytenr, u64 parent,
1200                                            u64 root_objectid, u64 owner,
1201                                            u64 offset, int refs_to_add)
1202 {
1203         struct btrfs_key key;
1204         struct extent_buffer *leaf;
1205         u32 size;
1206         u32 num_refs;
1207         int ret;
1208
1209         key.objectid = bytenr;
1210         if (parent) {
1211                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1212                 key.offset = parent;
1213                 size = sizeof(struct btrfs_shared_data_ref);
1214         } else {
1215                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1216                 key.offset = hash_extent_data_ref(root_objectid,
1217                                                   owner, offset);
1218                 size = sizeof(struct btrfs_extent_data_ref);
1219         }
1220
1221         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1222         if (ret && ret != -EEXIST)
1223                 goto fail;
1224
1225         leaf = path->nodes[0];
1226         if (parent) {
1227                 struct btrfs_shared_data_ref *ref;
1228                 ref = btrfs_item_ptr(leaf, path->slots[0],
1229                                      struct btrfs_shared_data_ref);
1230                 if (ret == 0) {
1231                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1232                 } else {
1233                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1234                         num_refs += refs_to_add;
1235                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1236                 }
1237         } else {
1238                 struct btrfs_extent_data_ref *ref;
1239                 while (ret == -EEXIST) {
1240                         ref = btrfs_item_ptr(leaf, path->slots[0],
1241                                              struct btrfs_extent_data_ref);
1242                         if (match_extent_data_ref(leaf, ref, root_objectid,
1243                                                   owner, offset))
1244                                 break;
1245                         btrfs_release_path(path);
1246                         key.offset++;
1247                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1248                                                       size);
1249                         if (ret && ret != -EEXIST)
1250                                 goto fail;
1251
1252                         leaf = path->nodes[0];
1253                 }
1254                 ref = btrfs_item_ptr(leaf, path->slots[0],
1255                                      struct btrfs_extent_data_ref);
1256                 if (ret == 0) {
1257                         btrfs_set_extent_data_ref_root(leaf, ref,
1258                                                        root_objectid);
1259                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1260                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1261                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1262                 } else {
1263                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1264                         num_refs += refs_to_add;
1265                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1266                 }
1267         }
1268         btrfs_mark_buffer_dirty(leaf);
1269         ret = 0;
1270 fail:
1271         btrfs_release_path(path);
1272         return ret;
1273 }
1274
1275 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1276                                            struct btrfs_root *root,
1277                                            struct btrfs_path *path,
1278                                            int refs_to_drop, int *last_ref)
1279 {
1280         struct btrfs_key key;
1281         struct btrfs_extent_data_ref *ref1 = NULL;
1282         struct btrfs_shared_data_ref *ref2 = NULL;
1283         struct extent_buffer *leaf;
1284         u32 num_refs = 0;
1285         int ret = 0;
1286
1287         leaf = path->nodes[0];
1288         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1289
1290         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1291                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1292                                       struct btrfs_extent_data_ref);
1293                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1294         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1295                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1296                                       struct btrfs_shared_data_ref);
1297                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1298 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1299         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1300                 struct btrfs_extent_ref_v0 *ref0;
1301                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1302                                       struct btrfs_extent_ref_v0);
1303                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1304 #endif
1305         } else {
1306                 BUG();
1307         }
1308
1309         BUG_ON(num_refs < refs_to_drop);
1310         num_refs -= refs_to_drop;
1311
1312         if (num_refs == 0) {
1313                 ret = btrfs_del_item(trans, root, path);
1314                 *last_ref = 1;
1315         } else {
1316                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1317                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1318                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1319                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1320 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1321                 else {
1322                         struct btrfs_extent_ref_v0 *ref0;
1323                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1324                                         struct btrfs_extent_ref_v0);
1325                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1326                 }
1327 #endif
1328                 btrfs_mark_buffer_dirty(leaf);
1329         }
1330         return ret;
1331 }
1332
1333 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1334                                           struct btrfs_path *path,
1335                                           struct btrfs_extent_inline_ref *iref)
1336 {
1337         struct btrfs_key key;
1338         struct extent_buffer *leaf;
1339         struct btrfs_extent_data_ref *ref1;
1340         struct btrfs_shared_data_ref *ref2;
1341         u32 num_refs = 0;
1342
1343         leaf = path->nodes[0];
1344         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1345         if (iref) {
1346                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1347                     BTRFS_EXTENT_DATA_REF_KEY) {
1348                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1349                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1350                 } else {
1351                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1352                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1353                 }
1354         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1355                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1356                                       struct btrfs_extent_data_ref);
1357                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1358         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1359                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1360                                       struct btrfs_shared_data_ref);
1361                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1362 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1363         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1364                 struct btrfs_extent_ref_v0 *ref0;
1365                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1366                                       struct btrfs_extent_ref_v0);
1367                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1368 #endif
1369         } else {
1370                 WARN_ON(1);
1371         }
1372         return num_refs;
1373 }
1374
1375 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1376                                           struct btrfs_root *root,
1377                                           struct btrfs_path *path,
1378                                           u64 bytenr, u64 parent,
1379                                           u64 root_objectid)
1380 {
1381         struct btrfs_key key;
1382         int ret;
1383
1384         key.objectid = bytenr;
1385         if (parent) {
1386                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1387                 key.offset = parent;
1388         } else {
1389                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1390                 key.offset = root_objectid;
1391         }
1392
1393         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1394         if (ret > 0)
1395                 ret = -ENOENT;
1396 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1397         if (ret == -ENOENT && parent) {
1398                 btrfs_release_path(path);
1399                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1400                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1401                 if (ret > 0)
1402                         ret = -ENOENT;
1403         }
1404 #endif
1405         return ret;
1406 }
1407
1408 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1409                                           struct btrfs_root *root,
1410                                           struct btrfs_path *path,
1411                                           u64 bytenr, u64 parent,
1412                                           u64 root_objectid)
1413 {
1414         struct btrfs_key key;
1415         int ret;
1416
1417         key.objectid = bytenr;
1418         if (parent) {
1419                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1420                 key.offset = parent;
1421         } else {
1422                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1423                 key.offset = root_objectid;
1424         }
1425
1426         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1427         btrfs_release_path(path);
1428         return ret;
1429 }
1430
1431 static inline int extent_ref_type(u64 parent, u64 owner)
1432 {
1433         int type;
1434         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1435                 if (parent > 0)
1436                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1437                 else
1438                         type = BTRFS_TREE_BLOCK_REF_KEY;
1439         } else {
1440                 if (parent > 0)
1441                         type = BTRFS_SHARED_DATA_REF_KEY;
1442                 else
1443                         type = BTRFS_EXTENT_DATA_REF_KEY;
1444         }
1445         return type;
1446 }
1447
1448 static int find_next_key(struct btrfs_path *path, int level,
1449                          struct btrfs_key *key)
1450
1451 {
1452         for (; level < BTRFS_MAX_LEVEL; level++) {
1453                 if (!path->nodes[level])
1454                         break;
1455                 if (path->slots[level] + 1 >=
1456                     btrfs_header_nritems(path->nodes[level]))
1457                         continue;
1458                 if (level == 0)
1459                         btrfs_item_key_to_cpu(path->nodes[level], key,
1460                                               path->slots[level] + 1);
1461                 else
1462                         btrfs_node_key_to_cpu(path->nodes[level], key,
1463                                               path->slots[level] + 1);
1464                 return 0;
1465         }
1466         return 1;
1467 }
1468
1469 /*
1470  * look for inline back ref. if back ref is found, *ref_ret is set
1471  * to the address of inline back ref, and 0 is returned.
1472  *
1473  * if back ref isn't found, *ref_ret is set to the address where it
1474  * should be inserted, and -ENOENT is returned.
1475  *
1476  * if insert is true and there are too many inline back refs, the path
1477  * points to the extent item, and -EAGAIN is returned.
1478  *
1479  * NOTE: inline back refs are ordered in the same way that back ref
1480  *       items in the tree are ordered.
1481  */
1482 static noinline_for_stack
1483 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1484                                  struct btrfs_root *root,
1485                                  struct btrfs_path *path,
1486                                  struct btrfs_extent_inline_ref **ref_ret,
1487                                  u64 bytenr, u64 num_bytes,
1488                                  u64 parent, u64 root_objectid,
1489                                  u64 owner, u64 offset, int insert)
1490 {
1491         struct btrfs_key key;
1492         struct extent_buffer *leaf;
1493         struct btrfs_extent_item *ei;
1494         struct btrfs_extent_inline_ref *iref;
1495         u64 flags;
1496         u64 item_size;
1497         unsigned long ptr;
1498         unsigned long end;
1499         int extra_size;
1500         int type;
1501         int want;
1502         int ret;
1503         int err = 0;
1504         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1505                                                  SKINNY_METADATA);
1506
1507         key.objectid = bytenr;
1508         key.type = BTRFS_EXTENT_ITEM_KEY;
1509         key.offset = num_bytes;
1510
1511         want = extent_ref_type(parent, owner);
1512         if (insert) {
1513                 extra_size = btrfs_extent_inline_ref_size(want);
1514                 path->keep_locks = 1;
1515         } else
1516                 extra_size = -1;
1517
1518         /*
1519          * Owner is our parent level, so we can just add one to get the level
1520          * for the block we are interested in.
1521          */
1522         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1523                 key.type = BTRFS_METADATA_ITEM_KEY;
1524                 key.offset = owner;
1525         }
1526
1527 again:
1528         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1529         if (ret < 0) {
1530                 err = ret;
1531                 goto out;
1532         }
1533
1534         /*
1535          * We may be a newly converted file system which still has the old fat
1536          * extent entries for metadata, so try and see if we have one of those.
1537          */
1538         if (ret > 0 && skinny_metadata) {
1539                 skinny_metadata = false;
1540                 if (path->slots[0]) {
1541                         path->slots[0]--;
1542                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1543                                               path->slots[0]);
1544                         if (key.objectid == bytenr &&
1545                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1546                             key.offset == num_bytes)
1547                                 ret = 0;
1548                 }
1549                 if (ret) {
1550                         key.objectid = bytenr;
1551                         key.type = BTRFS_EXTENT_ITEM_KEY;
1552                         key.offset = num_bytes;
1553                         btrfs_release_path(path);
1554                         goto again;
1555                 }
1556         }
1557
1558         if (ret && !insert) {
1559                 err = -ENOENT;
1560                 goto out;
1561         } else if (WARN_ON(ret)) {
1562                 err = -EIO;
1563                 goto out;
1564         }
1565
1566         leaf = path->nodes[0];
1567         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1568 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1569         if (item_size < sizeof(*ei)) {
1570                 if (!insert) {
1571                         err = -ENOENT;
1572                         goto out;
1573                 }
1574                 ret = convert_extent_item_v0(trans, root, path, owner,
1575                                              extra_size);
1576                 if (ret < 0) {
1577                         err = ret;
1578                         goto out;
1579                 }
1580                 leaf = path->nodes[0];
1581                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1582         }
1583 #endif
1584         BUG_ON(item_size < sizeof(*ei));
1585
1586         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1587         flags = btrfs_extent_flags(leaf, ei);
1588
1589         ptr = (unsigned long)(ei + 1);
1590         end = (unsigned long)ei + item_size;
1591
1592         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1593                 ptr += sizeof(struct btrfs_tree_block_info);
1594                 BUG_ON(ptr > end);
1595         }
1596
1597         err = -ENOENT;
1598         while (1) {
1599                 if (ptr >= end) {
1600                         WARN_ON(ptr > end);
1601                         break;
1602                 }
1603                 iref = (struct btrfs_extent_inline_ref *)ptr;
1604                 type = btrfs_extent_inline_ref_type(leaf, iref);
1605                 if (want < type)
1606                         break;
1607                 if (want > type) {
1608                         ptr += btrfs_extent_inline_ref_size(type);
1609                         continue;
1610                 }
1611
1612                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1613                         struct btrfs_extent_data_ref *dref;
1614                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1615                         if (match_extent_data_ref(leaf, dref, root_objectid,
1616                                                   owner, offset)) {
1617                                 err = 0;
1618                                 break;
1619                         }
1620                         if (hash_extent_data_ref_item(leaf, dref) <
1621                             hash_extent_data_ref(root_objectid, owner, offset))
1622                                 break;
1623                 } else {
1624                         u64 ref_offset;
1625                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1626                         if (parent > 0) {
1627                                 if (parent == ref_offset) {
1628                                         err = 0;
1629                                         break;
1630                                 }
1631                                 if (ref_offset < parent)
1632                                         break;
1633                         } else {
1634                                 if (root_objectid == ref_offset) {
1635                                         err = 0;
1636                                         break;
1637                                 }
1638                                 if (ref_offset < root_objectid)
1639                                         break;
1640                         }
1641                 }
1642                 ptr += btrfs_extent_inline_ref_size(type);
1643         }
1644         if (err == -ENOENT && insert) {
1645                 if (item_size + extra_size >=
1646                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1647                         err = -EAGAIN;
1648                         goto out;
1649                 }
1650                 /*
1651                  * To add new inline back ref, we have to make sure
1652                  * there is no corresponding back ref item.
1653                  * For simplicity, we just do not add new inline back
1654                  * ref if there is any kind of item for this block
1655                  */
1656                 if (find_next_key(path, 0, &key) == 0 &&
1657                     key.objectid == bytenr &&
1658                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1659                         err = -EAGAIN;
1660                         goto out;
1661                 }
1662         }
1663         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1664 out:
1665         if (insert) {
1666                 path->keep_locks = 0;
1667                 btrfs_unlock_up_safe(path, 1);
1668         }
1669         return err;
1670 }
1671
1672 /*
1673  * helper to add new inline back ref
1674  */
1675 static noinline_for_stack
1676 void setup_inline_extent_backref(struct btrfs_root *root,
1677                                  struct btrfs_path *path,
1678                                  struct btrfs_extent_inline_ref *iref,
1679                                  u64 parent, u64 root_objectid,
1680                                  u64 owner, u64 offset, int refs_to_add,
1681                                  struct btrfs_delayed_extent_op *extent_op)
1682 {
1683         struct extent_buffer *leaf;
1684         struct btrfs_extent_item *ei;
1685         unsigned long ptr;
1686         unsigned long end;
1687         unsigned long item_offset;
1688         u64 refs;
1689         int size;
1690         int type;
1691
1692         leaf = path->nodes[0];
1693         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1694         item_offset = (unsigned long)iref - (unsigned long)ei;
1695
1696         type = extent_ref_type(parent, owner);
1697         size = btrfs_extent_inline_ref_size(type);
1698
1699         btrfs_extend_item(root, path, size);
1700
1701         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1702         refs = btrfs_extent_refs(leaf, ei);
1703         refs += refs_to_add;
1704         btrfs_set_extent_refs(leaf, ei, refs);
1705         if (extent_op)
1706                 __run_delayed_extent_op(extent_op, leaf, ei);
1707
1708         ptr = (unsigned long)ei + item_offset;
1709         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1710         if (ptr < end - size)
1711                 memmove_extent_buffer(leaf, ptr + size, ptr,
1712                                       end - size - ptr);
1713
1714         iref = (struct btrfs_extent_inline_ref *)ptr;
1715         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1716         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1717                 struct btrfs_extent_data_ref *dref;
1718                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1719                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1720                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1721                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1722                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1723         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1724                 struct btrfs_shared_data_ref *sref;
1725                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1726                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1727                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1728         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1729                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1730         } else {
1731                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1732         }
1733         btrfs_mark_buffer_dirty(leaf);
1734 }
1735
1736 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1737                                  struct btrfs_root *root,
1738                                  struct btrfs_path *path,
1739                                  struct btrfs_extent_inline_ref **ref_ret,
1740                                  u64 bytenr, u64 num_bytes, u64 parent,
1741                                  u64 root_objectid, u64 owner, u64 offset)
1742 {
1743         int ret;
1744
1745         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1746                                            bytenr, num_bytes, parent,
1747                                            root_objectid, owner, offset, 0);
1748         if (ret != -ENOENT)
1749                 return ret;
1750
1751         btrfs_release_path(path);
1752         *ref_ret = NULL;
1753
1754         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1755                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1756                                             root_objectid);
1757         } else {
1758                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1759                                              root_objectid, owner, offset);
1760         }
1761         return ret;
1762 }
1763
1764 /*
1765  * helper to update/remove inline back ref
1766  */
1767 static noinline_for_stack
1768 void update_inline_extent_backref(struct btrfs_root *root,
1769                                   struct btrfs_path *path,
1770                                   struct btrfs_extent_inline_ref *iref,
1771                                   int refs_to_mod,
1772                                   struct btrfs_delayed_extent_op *extent_op,
1773                                   int *last_ref)
1774 {
1775         struct extent_buffer *leaf;
1776         struct btrfs_extent_item *ei;
1777         struct btrfs_extent_data_ref *dref = NULL;
1778         struct btrfs_shared_data_ref *sref = NULL;
1779         unsigned long ptr;
1780         unsigned long end;
1781         u32 item_size;
1782         int size;
1783         int type;
1784         u64 refs;
1785
1786         leaf = path->nodes[0];
1787         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1788         refs = btrfs_extent_refs(leaf, ei);
1789         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1790         refs += refs_to_mod;
1791         btrfs_set_extent_refs(leaf, ei, refs);
1792         if (extent_op)
1793                 __run_delayed_extent_op(extent_op, leaf, ei);
1794
1795         type = btrfs_extent_inline_ref_type(leaf, iref);
1796
1797         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1798                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1799                 refs = btrfs_extent_data_ref_count(leaf, dref);
1800         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1801                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1802                 refs = btrfs_shared_data_ref_count(leaf, sref);
1803         } else {
1804                 refs = 1;
1805                 BUG_ON(refs_to_mod != -1);
1806         }
1807
1808         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1809         refs += refs_to_mod;
1810
1811         if (refs > 0) {
1812                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1813                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1814                 else
1815                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1816         } else {
1817                 *last_ref = 1;
1818                 size =  btrfs_extent_inline_ref_size(type);
1819                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1820                 ptr = (unsigned long)iref;
1821                 end = (unsigned long)ei + item_size;
1822                 if (ptr + size < end)
1823                         memmove_extent_buffer(leaf, ptr, ptr + size,
1824                                               end - ptr - size);
1825                 item_size -= size;
1826                 btrfs_truncate_item(root, path, item_size, 1);
1827         }
1828         btrfs_mark_buffer_dirty(leaf);
1829 }
1830
1831 static noinline_for_stack
1832 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1833                                  struct btrfs_root *root,
1834                                  struct btrfs_path *path,
1835                                  u64 bytenr, u64 num_bytes, u64 parent,
1836                                  u64 root_objectid, u64 owner,
1837                                  u64 offset, int refs_to_add,
1838                                  struct btrfs_delayed_extent_op *extent_op)
1839 {
1840         struct btrfs_extent_inline_ref *iref;
1841         int ret;
1842
1843         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1844                                            bytenr, num_bytes, parent,
1845                                            root_objectid, owner, offset, 1);
1846         if (ret == 0) {
1847                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1848                 update_inline_extent_backref(root, path, iref,
1849                                              refs_to_add, extent_op, NULL);
1850         } else if (ret == -ENOENT) {
1851                 setup_inline_extent_backref(root, path, iref, parent,
1852                                             root_objectid, owner, offset,
1853                                             refs_to_add, extent_op);
1854                 ret = 0;
1855         }
1856         return ret;
1857 }
1858
1859 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1860                                  struct btrfs_root *root,
1861                                  struct btrfs_path *path,
1862                                  u64 bytenr, u64 parent, u64 root_objectid,
1863                                  u64 owner, u64 offset, int refs_to_add)
1864 {
1865         int ret;
1866         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1867                 BUG_ON(refs_to_add != 1);
1868                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1869                                             parent, root_objectid);
1870         } else {
1871                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1872                                              parent, root_objectid,
1873                                              owner, offset, refs_to_add);
1874         }
1875         return ret;
1876 }
1877
1878 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1879                                  struct btrfs_root *root,
1880                                  struct btrfs_path *path,
1881                                  struct btrfs_extent_inline_ref *iref,
1882                                  int refs_to_drop, int is_data, int *last_ref)
1883 {
1884         int ret = 0;
1885
1886         BUG_ON(!is_data && refs_to_drop != 1);
1887         if (iref) {
1888                 update_inline_extent_backref(root, path, iref,
1889                                              -refs_to_drop, NULL, last_ref);
1890         } else if (is_data) {
1891                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1892                                              last_ref);
1893         } else {
1894                 *last_ref = 1;
1895                 ret = btrfs_del_item(trans, root, path);
1896         }
1897         return ret;
1898 }
1899
1900 static int btrfs_issue_discard(struct block_device *bdev,
1901                                 u64 start, u64 len)
1902 {
1903         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1904 }
1905
1906 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1907                                 u64 num_bytes, u64 *actual_bytes)
1908 {
1909         int ret;
1910         u64 discarded_bytes = 0;
1911         struct btrfs_bio *bbio = NULL;
1912
1913
1914         /* Tell the block device(s) that the sectors can be discarded */
1915         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1916                               bytenr, &num_bytes, &bbio, 0);
1917         /* Error condition is -ENOMEM */
1918         if (!ret) {
1919                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1920                 int i;
1921
1922
1923                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1924                         if (!stripe->dev->can_discard)
1925                                 continue;
1926
1927                         ret = btrfs_issue_discard(stripe->dev->bdev,
1928                                                   stripe->physical,
1929                                                   stripe->length);
1930                         if (!ret)
1931                                 discarded_bytes += stripe->length;
1932                         else if (ret != -EOPNOTSUPP)
1933                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1934
1935                         /*
1936                          * Just in case we get back EOPNOTSUPP for some reason,
1937                          * just ignore the return value so we don't screw up
1938                          * people calling discard_extent.
1939                          */
1940                         ret = 0;
1941                 }
1942                 kfree(bbio);
1943         }
1944
1945         if (actual_bytes)
1946                 *actual_bytes = discarded_bytes;
1947
1948
1949         if (ret == -EOPNOTSUPP)
1950                 ret = 0;
1951         return ret;
1952 }
1953
1954 /* Can return -ENOMEM */
1955 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1956                          struct btrfs_root *root,
1957                          u64 bytenr, u64 num_bytes, u64 parent,
1958                          u64 root_objectid, u64 owner, u64 offset,
1959                          int no_quota)
1960 {
1961         int ret;
1962         struct btrfs_fs_info *fs_info = root->fs_info;
1963
1964         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1965                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1966
1967         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1968                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1969                                         num_bytes,
1970                                         parent, root_objectid, (int)owner,
1971                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
1972         } else {
1973                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1974                                         num_bytes,
1975                                         parent, root_objectid, owner, offset,
1976                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
1977         }
1978         return ret;
1979 }
1980
1981 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1982                                   struct btrfs_root *root,
1983                                   u64 bytenr, u64 num_bytes,
1984                                   u64 parent, u64 root_objectid,
1985                                   u64 owner, u64 offset, int refs_to_add,
1986                                   int no_quota,
1987                                   struct btrfs_delayed_extent_op *extent_op)
1988 {
1989         struct btrfs_fs_info *fs_info = root->fs_info;
1990         struct btrfs_path *path;
1991         struct extent_buffer *leaf;
1992         struct btrfs_extent_item *item;
1993         struct btrfs_key key;
1994         u64 refs;
1995         int ret;
1996         enum btrfs_qgroup_operation_type type = BTRFS_QGROUP_OPER_ADD_EXCL;
1997
1998         path = btrfs_alloc_path();
1999         if (!path)
2000                 return -ENOMEM;
2001
2002         if (!is_fstree(root_objectid) || !root->fs_info->quota_enabled)
2003                 no_quota = 1;
2004
2005         path->reada = 1;
2006         path->leave_spinning = 1;
2007         /* this will setup the path even if it fails to insert the back ref */
2008         ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2009                                            bytenr, num_bytes, parent,
2010                                            root_objectid, owner, offset,
2011                                            refs_to_add, extent_op);
2012         if ((ret < 0 && ret != -EAGAIN) || (!ret && no_quota))
2013                 goto out;
2014         /*
2015          * Ok we were able to insert an inline extent and it appears to be a new
2016          * reference, deal with the qgroup accounting.
2017          */
2018         if (!ret && !no_quota) {
2019                 ASSERT(root->fs_info->quota_enabled);
2020                 leaf = path->nodes[0];
2021                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2022                 item = btrfs_item_ptr(leaf, path->slots[0],
2023                                       struct btrfs_extent_item);
2024                 if (btrfs_extent_refs(leaf, item) > (u64)refs_to_add)
2025                         type = BTRFS_QGROUP_OPER_ADD_SHARED;
2026                 btrfs_release_path(path);
2027
2028                 ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
2029                                               bytenr, num_bytes, type, 0);
2030                 goto out;
2031         }
2032
2033         /*
2034          * Ok we had -EAGAIN which means we didn't have space to insert and
2035          * inline extent ref, so just update the reference count and add a
2036          * normal backref.
2037          */
2038         leaf = path->nodes[0];
2039         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2040         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2041         refs = btrfs_extent_refs(leaf, item);
2042         if (refs)
2043                 type = BTRFS_QGROUP_OPER_ADD_SHARED;
2044         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2045         if (extent_op)
2046                 __run_delayed_extent_op(extent_op, leaf, item);
2047
2048         btrfs_mark_buffer_dirty(leaf);
2049         btrfs_release_path(path);
2050
2051         if (!no_quota) {
2052                 ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
2053                                               bytenr, num_bytes, type, 0);
2054                 if (ret)
2055                         goto out;
2056         }
2057
2058         path->reada = 1;
2059         path->leave_spinning = 1;
2060         /* now insert the actual backref */
2061         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2062                                     path, bytenr, parent, root_objectid,
2063                                     owner, offset, refs_to_add);
2064         if (ret)
2065                 btrfs_abort_transaction(trans, root, ret);
2066 out:
2067         btrfs_free_path(path);
2068         return ret;
2069 }
2070
2071 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2072                                 struct btrfs_root *root,
2073                                 struct btrfs_delayed_ref_node *node,
2074                                 struct btrfs_delayed_extent_op *extent_op,
2075                                 int insert_reserved)
2076 {
2077         int ret = 0;
2078         struct btrfs_delayed_data_ref *ref;
2079         struct btrfs_key ins;
2080         u64 parent = 0;
2081         u64 ref_root = 0;
2082         u64 flags = 0;
2083
2084         ins.objectid = node->bytenr;
2085         ins.offset = node->num_bytes;
2086         ins.type = BTRFS_EXTENT_ITEM_KEY;
2087
2088         ref = btrfs_delayed_node_to_data_ref(node);
2089         trace_run_delayed_data_ref(node, ref, node->action);
2090
2091         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2092                 parent = ref->parent;
2093         ref_root = ref->root;
2094
2095         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2096                 if (extent_op)
2097                         flags |= extent_op->flags_to_set;
2098                 ret = alloc_reserved_file_extent(trans, root,
2099                                                  parent, ref_root, flags,
2100                                                  ref->objectid, ref->offset,
2101                                                  &ins, node->ref_mod);
2102         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2103                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2104                                              node->num_bytes, parent,
2105                                              ref_root, ref->objectid,
2106                                              ref->offset, node->ref_mod,
2107                                              node->no_quota, extent_op);
2108         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2109                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2110                                           node->num_bytes, parent,
2111                                           ref_root, ref->objectid,
2112                                           ref->offset, node->ref_mod,
2113                                           extent_op, node->no_quota);
2114         } else {
2115                 BUG();
2116         }
2117         return ret;
2118 }
2119
2120 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2121                                     struct extent_buffer *leaf,
2122                                     struct btrfs_extent_item *ei)
2123 {
2124         u64 flags = btrfs_extent_flags(leaf, ei);
2125         if (extent_op->update_flags) {
2126                 flags |= extent_op->flags_to_set;
2127                 btrfs_set_extent_flags(leaf, ei, flags);
2128         }
2129
2130         if (extent_op->update_key) {
2131                 struct btrfs_tree_block_info *bi;
2132                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2133                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2134                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2135         }
2136 }
2137
2138 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2139                                  struct btrfs_root *root,
2140                                  struct btrfs_delayed_ref_node *node,
2141                                  struct btrfs_delayed_extent_op *extent_op)
2142 {
2143         struct btrfs_key key;
2144         struct btrfs_path *path;
2145         struct btrfs_extent_item *ei;
2146         struct extent_buffer *leaf;
2147         u32 item_size;
2148         int ret;
2149         int err = 0;
2150         int metadata = !extent_op->is_data;
2151
2152         if (trans->aborted)
2153                 return 0;
2154
2155         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2156                 metadata = 0;
2157
2158         path = btrfs_alloc_path();
2159         if (!path)
2160                 return -ENOMEM;
2161
2162         key.objectid = node->bytenr;
2163
2164         if (metadata) {
2165                 key.type = BTRFS_METADATA_ITEM_KEY;
2166                 key.offset = extent_op->level;
2167         } else {
2168                 key.type = BTRFS_EXTENT_ITEM_KEY;
2169                 key.offset = node->num_bytes;
2170         }
2171
2172 again:
2173         path->reada = 1;
2174         path->leave_spinning = 1;
2175         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2176                                 path, 0, 1);
2177         if (ret < 0) {
2178                 err = ret;
2179                 goto out;
2180         }
2181         if (ret > 0) {
2182                 if (metadata) {
2183                         if (path->slots[0] > 0) {
2184                                 path->slots[0]--;
2185                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2186                                                       path->slots[0]);
2187                                 if (key.objectid == node->bytenr &&
2188                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2189                                     key.offset == node->num_bytes)
2190                                         ret = 0;
2191                         }
2192                         if (ret > 0) {
2193                                 btrfs_release_path(path);
2194                                 metadata = 0;
2195
2196                                 key.objectid = node->bytenr;
2197                                 key.offset = node->num_bytes;
2198                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2199                                 goto again;
2200                         }
2201                 } else {
2202                         err = -EIO;
2203                         goto out;
2204                 }
2205         }
2206
2207         leaf = path->nodes[0];
2208         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2209 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2210         if (item_size < sizeof(*ei)) {
2211                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2212                                              path, (u64)-1, 0);
2213                 if (ret < 0) {
2214                         err = ret;
2215                         goto out;
2216                 }
2217                 leaf = path->nodes[0];
2218                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2219         }
2220 #endif
2221         BUG_ON(item_size < sizeof(*ei));
2222         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2223         __run_delayed_extent_op(extent_op, leaf, ei);
2224
2225         btrfs_mark_buffer_dirty(leaf);
2226 out:
2227         btrfs_free_path(path);
2228         return err;
2229 }
2230
2231 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2232                                 struct btrfs_root *root,
2233                                 struct btrfs_delayed_ref_node *node,
2234                                 struct btrfs_delayed_extent_op *extent_op,
2235                                 int insert_reserved)
2236 {
2237         int ret = 0;
2238         struct btrfs_delayed_tree_ref *ref;
2239         struct btrfs_key ins;
2240         u64 parent = 0;
2241         u64 ref_root = 0;
2242         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2243                                                  SKINNY_METADATA);
2244
2245         ref = btrfs_delayed_node_to_tree_ref(node);
2246         trace_run_delayed_tree_ref(node, ref, node->action);
2247
2248         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2249                 parent = ref->parent;
2250         ref_root = ref->root;
2251
2252         ins.objectid = node->bytenr;
2253         if (skinny_metadata) {
2254                 ins.offset = ref->level;
2255                 ins.type = BTRFS_METADATA_ITEM_KEY;
2256         } else {
2257                 ins.offset = node->num_bytes;
2258                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2259         }
2260
2261         BUG_ON(node->ref_mod != 1);
2262         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2263                 BUG_ON(!extent_op || !extent_op->update_flags);
2264                 ret = alloc_reserved_tree_block(trans, root,
2265                                                 parent, ref_root,
2266                                                 extent_op->flags_to_set,
2267                                                 &extent_op->key,
2268                                                 ref->level, &ins,
2269                                                 node->no_quota);
2270         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2271                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2272                                              node->num_bytes, parent, ref_root,
2273                                              ref->level, 0, 1, node->no_quota,
2274                                              extent_op);
2275         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2276                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2277                                           node->num_bytes, parent, ref_root,
2278                                           ref->level, 0, 1, extent_op,
2279                                           node->no_quota);
2280         } else {
2281                 BUG();
2282         }
2283         return ret;
2284 }
2285
2286 /* helper function to actually process a single delayed ref entry */
2287 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2288                                struct btrfs_root *root,
2289                                struct btrfs_delayed_ref_node *node,
2290                                struct btrfs_delayed_extent_op *extent_op,
2291                                int insert_reserved)
2292 {
2293         int ret = 0;
2294
2295         if (trans->aborted) {
2296                 if (insert_reserved)
2297                         btrfs_pin_extent(root, node->bytenr,
2298                                          node->num_bytes, 1);
2299                 return 0;
2300         }
2301
2302         if (btrfs_delayed_ref_is_head(node)) {
2303                 struct btrfs_delayed_ref_head *head;
2304                 /*
2305                  * we've hit the end of the chain and we were supposed
2306                  * to insert this extent into the tree.  But, it got
2307                  * deleted before we ever needed to insert it, so all
2308                  * we have to do is clean up the accounting
2309                  */
2310                 BUG_ON(extent_op);
2311                 head = btrfs_delayed_node_to_head(node);
2312                 trace_run_delayed_ref_head(node, head, node->action);
2313
2314                 if (insert_reserved) {
2315                         btrfs_pin_extent(root, node->bytenr,
2316                                          node->num_bytes, 1);
2317                         if (head->is_data) {
2318                                 ret = btrfs_del_csums(trans, root,
2319                                                       node->bytenr,
2320                                                       node->num_bytes);
2321                         }
2322                 }
2323                 return ret;
2324         }
2325
2326         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2327             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2328                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2329                                            insert_reserved);
2330         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2331                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2332                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2333                                            insert_reserved);
2334         else
2335                 BUG();
2336         return ret;
2337 }
2338
2339 static noinline struct btrfs_delayed_ref_node *
2340 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2341 {
2342         struct rb_node *node;
2343         struct btrfs_delayed_ref_node *ref, *last = NULL;;
2344
2345         /*
2346          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2347          * this prevents ref count from going down to zero when
2348          * there still are pending delayed ref.
2349          */
2350         node = rb_first(&head->ref_root);
2351         while (node) {
2352                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2353                                 rb_node);
2354                 if (ref->action == BTRFS_ADD_DELAYED_REF)
2355                         return ref;
2356                 else if (last == NULL)
2357                         last = ref;
2358                 node = rb_next(node);
2359         }
2360         return last;
2361 }
2362
2363 /*
2364  * Returns 0 on success or if called with an already aborted transaction.
2365  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2366  */
2367 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2368                                              struct btrfs_root *root,
2369                                              unsigned long nr)
2370 {
2371         struct btrfs_delayed_ref_root *delayed_refs;
2372         struct btrfs_delayed_ref_node *ref;
2373         struct btrfs_delayed_ref_head *locked_ref = NULL;
2374         struct btrfs_delayed_extent_op *extent_op;
2375         struct btrfs_fs_info *fs_info = root->fs_info;
2376         ktime_t start = ktime_get();
2377         int ret;
2378         unsigned long count = 0;
2379         unsigned long actual_count = 0;
2380         int must_insert_reserved = 0;
2381
2382         delayed_refs = &trans->transaction->delayed_refs;
2383         while (1) {
2384                 if (!locked_ref) {
2385                         if (count >= nr)
2386                                 break;
2387
2388                         spin_lock(&delayed_refs->lock);
2389                         locked_ref = btrfs_select_ref_head(trans);
2390                         if (!locked_ref) {
2391                                 spin_unlock(&delayed_refs->lock);
2392                                 break;
2393                         }
2394
2395                         /* grab the lock that says we are going to process
2396                          * all the refs for this head */
2397                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2398                         spin_unlock(&delayed_refs->lock);
2399                         /*
2400                          * we may have dropped the spin lock to get the head
2401                          * mutex lock, and that might have given someone else
2402                          * time to free the head.  If that's true, it has been
2403                          * removed from our list and we can move on.
2404                          */
2405                         if (ret == -EAGAIN) {
2406                                 locked_ref = NULL;
2407                                 count++;
2408                                 continue;
2409                         }
2410                 }
2411
2412                 /*
2413                  * We need to try and merge add/drops of the same ref since we
2414                  * can run into issues with relocate dropping the implicit ref
2415                  * and then it being added back again before the drop can
2416                  * finish.  If we merged anything we need to re-loop so we can
2417                  * get a good ref.
2418                  */
2419                 spin_lock(&locked_ref->lock);
2420                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2421                                          locked_ref);
2422
2423                 /*
2424                  * locked_ref is the head node, so we have to go one
2425                  * node back for any delayed ref updates
2426                  */
2427                 ref = select_delayed_ref(locked_ref);
2428
2429                 if (ref && ref->seq &&
2430                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2431                         spin_unlock(&locked_ref->lock);
2432                         btrfs_delayed_ref_unlock(locked_ref);
2433                         spin_lock(&delayed_refs->lock);
2434                         locked_ref->processing = 0;
2435                         delayed_refs->num_heads_ready++;
2436                         spin_unlock(&delayed_refs->lock);
2437                         locked_ref = NULL;
2438                         cond_resched();
2439                         count++;
2440                         continue;
2441                 }
2442
2443                 /*
2444                  * record the must insert reserved flag before we
2445                  * drop the spin lock.
2446                  */
2447                 must_insert_reserved = locked_ref->must_insert_reserved;
2448                 locked_ref->must_insert_reserved = 0;
2449
2450                 extent_op = locked_ref->extent_op;
2451                 locked_ref->extent_op = NULL;
2452
2453                 if (!ref) {
2454
2455
2456                         /* All delayed refs have been processed, Go ahead
2457                          * and send the head node to run_one_delayed_ref,
2458                          * so that any accounting fixes can happen
2459                          */
2460                         ref = &locked_ref->node;
2461
2462                         if (extent_op && must_insert_reserved) {
2463                                 btrfs_free_delayed_extent_op(extent_op);
2464                                 extent_op = NULL;
2465                         }
2466
2467                         if (extent_op) {
2468                                 spin_unlock(&locked_ref->lock);
2469                                 ret = run_delayed_extent_op(trans, root,
2470                                                             ref, extent_op);
2471                                 btrfs_free_delayed_extent_op(extent_op);
2472
2473                                 if (ret) {
2474                                         /*
2475                                          * Need to reset must_insert_reserved if
2476                                          * there was an error so the abort stuff
2477                                          * can cleanup the reserved space
2478                                          * properly.
2479                                          */
2480                                         if (must_insert_reserved)
2481                                                 locked_ref->must_insert_reserved = 1;
2482                                         locked_ref->processing = 0;
2483                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2484                                         btrfs_delayed_ref_unlock(locked_ref);
2485                                         return ret;
2486                                 }
2487                                 continue;
2488                         }
2489
2490                         /*
2491                          * Need to drop our head ref lock and re-aqcuire the
2492                          * delayed ref lock and then re-check to make sure
2493                          * nobody got added.
2494                          */
2495                         spin_unlock(&locked_ref->lock);
2496                         spin_lock(&delayed_refs->lock);
2497                         spin_lock(&locked_ref->lock);
2498                         if (rb_first(&locked_ref->ref_root) ||
2499                             locked_ref->extent_op) {
2500                                 spin_unlock(&locked_ref->lock);
2501                                 spin_unlock(&delayed_refs->lock);
2502                                 continue;
2503                         }
2504                         ref->in_tree = 0;
2505                         delayed_refs->num_heads--;
2506                         rb_erase(&locked_ref->href_node,
2507                                  &delayed_refs->href_root);
2508                         spin_unlock(&delayed_refs->lock);
2509                 } else {
2510                         actual_count++;
2511                         ref->in_tree = 0;
2512                         rb_erase(&ref->rb_node, &locked_ref->ref_root);
2513                 }
2514                 atomic_dec(&delayed_refs->num_entries);
2515
2516                 if (!btrfs_delayed_ref_is_head(ref)) {
2517                         /*
2518                          * when we play the delayed ref, also correct the
2519                          * ref_mod on head
2520                          */
2521                         switch (ref->action) {
2522                         case BTRFS_ADD_DELAYED_REF:
2523                         case BTRFS_ADD_DELAYED_EXTENT:
2524                                 locked_ref->node.ref_mod -= ref->ref_mod;
2525                                 break;
2526                         case BTRFS_DROP_DELAYED_REF:
2527                                 locked_ref->node.ref_mod += ref->ref_mod;
2528                                 break;
2529                         default:
2530                                 WARN_ON(1);
2531                         }
2532                 }
2533                 spin_unlock(&locked_ref->lock);
2534
2535                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2536                                           must_insert_reserved);
2537
2538                 btrfs_free_delayed_extent_op(extent_op);
2539                 if (ret) {
2540                         locked_ref->processing = 0;
2541                         btrfs_delayed_ref_unlock(locked_ref);
2542                         btrfs_put_delayed_ref(ref);
2543                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2544                         return ret;
2545                 }
2546
2547                 /*
2548                  * If this node is a head, that means all the refs in this head
2549                  * have been dealt with, and we will pick the next head to deal
2550                  * with, so we must unlock the head and drop it from the cluster
2551                  * list before we release it.
2552                  */
2553                 if (btrfs_delayed_ref_is_head(ref)) {
2554                         btrfs_delayed_ref_unlock(locked_ref);
2555                         locked_ref = NULL;
2556                 }
2557                 btrfs_put_delayed_ref(ref);
2558                 count++;
2559                 cond_resched();
2560         }
2561
2562         /*
2563          * We don't want to include ref heads since we can have empty ref heads
2564          * and those will drastically skew our runtime down since we just do
2565          * accounting, no actual extent tree updates.
2566          */
2567         if (actual_count > 0) {
2568                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2569                 u64 avg;
2570
2571                 /*
2572                  * We weigh the current average higher than our current runtime
2573                  * to avoid large swings in the average.
2574                  */
2575                 spin_lock(&delayed_refs->lock);
2576                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2577                 avg = div64_u64(avg, 4);
2578                 fs_info->avg_delayed_ref_runtime = avg;
2579                 spin_unlock(&delayed_refs->lock);
2580         }
2581         return 0;
2582 }
2583
2584 #ifdef SCRAMBLE_DELAYED_REFS
2585 /*
2586  * Normally delayed refs get processed in ascending bytenr order. This
2587  * correlates in most cases to the order added. To expose dependencies on this
2588  * order, we start to process the tree in the middle instead of the beginning
2589  */
2590 static u64 find_middle(struct rb_root *root)
2591 {
2592         struct rb_node *n = root->rb_node;
2593         struct btrfs_delayed_ref_node *entry;
2594         int alt = 1;
2595         u64 middle;
2596         u64 first = 0, last = 0;
2597
2598         n = rb_first(root);
2599         if (n) {
2600                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2601                 first = entry->bytenr;
2602         }
2603         n = rb_last(root);
2604         if (n) {
2605                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2606                 last = entry->bytenr;
2607         }
2608         n = root->rb_node;
2609
2610         while (n) {
2611                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2612                 WARN_ON(!entry->in_tree);
2613
2614                 middle = entry->bytenr;
2615
2616                 if (alt)
2617                         n = n->rb_left;
2618                 else
2619                         n = n->rb_right;
2620
2621                 alt = 1 - alt;
2622         }
2623         return middle;
2624 }
2625 #endif
2626
2627 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2628 {
2629         u64 num_bytes;
2630
2631         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2632                              sizeof(struct btrfs_extent_inline_ref));
2633         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2634                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2635
2636         /*
2637          * We don't ever fill up leaves all the way so multiply by 2 just to be
2638          * closer to what we're really going to want to ouse.
2639          */
2640         return div64_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2641 }
2642
2643 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2644                                        struct btrfs_root *root)
2645 {
2646         struct btrfs_block_rsv *global_rsv;
2647         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2648         u64 num_bytes;
2649         int ret = 0;
2650
2651         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2652         num_heads = heads_to_leaves(root, num_heads);
2653         if (num_heads > 1)
2654                 num_bytes += (num_heads - 1) * root->leafsize;
2655         num_bytes <<= 1;
2656         global_rsv = &root->fs_info->global_block_rsv;
2657
2658         /*
2659          * If we can't allocate any more chunks lets make sure we have _lots_ of
2660          * wiggle room since running delayed refs can create more delayed refs.
2661          */
2662         if (global_rsv->space_info->full)
2663                 num_bytes <<= 1;
2664
2665         spin_lock(&global_rsv->lock);
2666         if (global_rsv->reserved <= num_bytes)
2667                 ret = 1;
2668         spin_unlock(&global_rsv->lock);
2669         return ret;
2670 }
2671
2672 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2673                                        struct btrfs_root *root)
2674 {
2675         struct btrfs_fs_info *fs_info = root->fs_info;
2676         u64 num_entries =
2677                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2678         u64 avg_runtime;
2679         u64 val;
2680
2681         smp_mb();
2682         avg_runtime = fs_info->avg_delayed_ref_runtime;
2683         val = num_entries * avg_runtime;
2684         if (num_entries * avg_runtime >= NSEC_PER_SEC)
2685                 return 1;
2686         if (val >= NSEC_PER_SEC / 2)
2687                 return 2;
2688
2689         return btrfs_check_space_for_delayed_refs(trans, root);
2690 }
2691
2692 struct async_delayed_refs {
2693         struct btrfs_root *root;
2694         int count;
2695         int error;
2696         int sync;
2697         struct completion wait;
2698         struct btrfs_work work;
2699 };
2700
2701 static void delayed_ref_async_start(struct btrfs_work *work)
2702 {
2703         struct async_delayed_refs *async;
2704         struct btrfs_trans_handle *trans;
2705         int ret;
2706
2707         async = container_of(work, struct async_delayed_refs, work);
2708
2709         trans = btrfs_join_transaction(async->root);
2710         if (IS_ERR(trans)) {
2711                 async->error = PTR_ERR(trans);
2712                 goto done;
2713         }
2714
2715         /*
2716          * trans->sync means that when we call end_transaciton, we won't
2717          * wait on delayed refs
2718          */
2719         trans->sync = true;
2720         ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2721         if (ret)
2722                 async->error = ret;
2723
2724         ret = btrfs_end_transaction(trans, async->root);
2725         if (ret && !async->error)
2726                 async->error = ret;
2727 done:
2728         if (async->sync)
2729                 complete(&async->wait);
2730         else
2731                 kfree(async);
2732 }
2733
2734 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2735                                  unsigned long count, int wait)
2736 {
2737         struct async_delayed_refs *async;
2738         int ret;
2739
2740         async = kmalloc(sizeof(*async), GFP_NOFS);
2741         if (!async)
2742                 return -ENOMEM;
2743
2744         async->root = root->fs_info->tree_root;
2745         async->count = count;
2746         async->error = 0;
2747         if (wait)
2748                 async->sync = 1;
2749         else
2750                 async->sync = 0;
2751         init_completion(&async->wait);
2752
2753         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2754                         delayed_ref_async_start, NULL, NULL);
2755
2756         btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2757
2758         if (wait) {
2759                 wait_for_completion(&async->wait);
2760                 ret = async->error;
2761                 kfree(async);
2762                 return ret;
2763         }
2764         return 0;
2765 }
2766
2767 /*
2768  * this starts processing the delayed reference count updates and
2769  * extent insertions we have queued up so far.  count can be
2770  * 0, which means to process everything in the tree at the start
2771  * of the run (but not newly added entries), or it can be some target
2772  * number you'd like to process.
2773  *
2774  * Returns 0 on success or if called with an aborted transaction
2775  * Returns <0 on error and aborts the transaction
2776  */
2777 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2778                            struct btrfs_root *root, unsigned long count)
2779 {
2780         struct rb_node *node;
2781         struct btrfs_delayed_ref_root *delayed_refs;
2782         struct btrfs_delayed_ref_head *head;
2783         int ret;
2784         int run_all = count == (unsigned long)-1;
2785         int run_most = 0;
2786
2787         /* We'll clean this up in btrfs_cleanup_transaction */
2788         if (trans->aborted)
2789                 return 0;
2790
2791         if (root == root->fs_info->extent_root)
2792                 root = root->fs_info->tree_root;
2793
2794         delayed_refs = &trans->transaction->delayed_refs;
2795         if (count == 0) {
2796                 count = atomic_read(&delayed_refs->num_entries) * 2;
2797                 run_most = 1;
2798         }
2799
2800 again:
2801 #ifdef SCRAMBLE_DELAYED_REFS
2802         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2803 #endif
2804         ret = __btrfs_run_delayed_refs(trans, root, count);
2805         if (ret < 0) {
2806                 btrfs_abort_transaction(trans, root, ret);
2807                 return ret;
2808         }
2809
2810         if (run_all) {
2811                 if (!list_empty(&trans->new_bgs))
2812                         btrfs_create_pending_block_groups(trans, root);
2813
2814                 spin_lock(&delayed_refs->lock);
2815                 node = rb_first(&delayed_refs->href_root);
2816                 if (!node) {
2817                         spin_unlock(&delayed_refs->lock);
2818                         goto out;
2819                 }
2820                 count = (unsigned long)-1;
2821
2822                 while (node) {
2823                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2824                                         href_node);
2825                         if (btrfs_delayed_ref_is_head(&head->node)) {
2826                                 struct btrfs_delayed_ref_node *ref;
2827
2828                                 ref = &head->node;
2829                                 atomic_inc(&ref->refs);
2830
2831                                 spin_unlock(&delayed_refs->lock);
2832                                 /*
2833                                  * Mutex was contended, block until it's
2834                                  * released and try again
2835                                  */
2836                                 mutex_lock(&head->mutex);
2837                                 mutex_unlock(&head->mutex);
2838
2839                                 btrfs_put_delayed_ref(ref);
2840                                 cond_resched();
2841                                 goto again;
2842                         } else {
2843                                 WARN_ON(1);
2844                         }
2845                         node = rb_next(node);
2846                 }
2847                 spin_unlock(&delayed_refs->lock);
2848                 cond_resched();
2849                 goto again;
2850         }
2851 out:
2852         ret = btrfs_delayed_qgroup_accounting(trans, root->fs_info);
2853         if (ret)
2854                 return ret;
2855         assert_qgroups_uptodate(trans);
2856         return 0;
2857 }
2858
2859 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2860                                 struct btrfs_root *root,
2861                                 u64 bytenr, u64 num_bytes, u64 flags,
2862                                 int level, int is_data)
2863 {
2864         struct btrfs_delayed_extent_op *extent_op;
2865         int ret;
2866
2867         extent_op = btrfs_alloc_delayed_extent_op();
2868         if (!extent_op)
2869                 return -ENOMEM;
2870
2871         extent_op->flags_to_set = flags;
2872         extent_op->update_flags = 1;
2873         extent_op->update_key = 0;
2874         extent_op->is_data = is_data ? 1 : 0;
2875         extent_op->level = level;
2876
2877         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2878                                           num_bytes, extent_op);
2879         if (ret)
2880                 btrfs_free_delayed_extent_op(extent_op);
2881         return ret;
2882 }
2883
2884 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2885                                       struct btrfs_root *root,
2886                                       struct btrfs_path *path,
2887                                       u64 objectid, u64 offset, u64 bytenr)
2888 {
2889         struct btrfs_delayed_ref_head *head;
2890         struct btrfs_delayed_ref_node *ref;
2891         struct btrfs_delayed_data_ref *data_ref;
2892         struct btrfs_delayed_ref_root *delayed_refs;
2893         struct rb_node *node;
2894         int ret = 0;
2895
2896         delayed_refs = &trans->transaction->delayed_refs;
2897         spin_lock(&delayed_refs->lock);
2898         head = btrfs_find_delayed_ref_head(trans, bytenr);
2899         if (!head) {
2900                 spin_unlock(&delayed_refs->lock);
2901                 return 0;
2902         }
2903
2904         if (!mutex_trylock(&head->mutex)) {
2905                 atomic_inc(&head->node.refs);
2906                 spin_unlock(&delayed_refs->lock);
2907
2908                 btrfs_release_path(path);
2909
2910                 /*
2911                  * Mutex was contended, block until it's released and let
2912                  * caller try again
2913                  */
2914                 mutex_lock(&head->mutex);
2915                 mutex_unlock(&head->mutex);
2916                 btrfs_put_delayed_ref(&head->node);
2917                 return -EAGAIN;
2918         }
2919         spin_unlock(&delayed_refs->lock);
2920
2921         spin_lock(&head->lock);
2922         node = rb_first(&head->ref_root);
2923         while (node) {
2924                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2925                 node = rb_next(node);
2926
2927                 /* If it's a shared ref we know a cross reference exists */
2928                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2929                         ret = 1;
2930                         break;
2931                 }
2932
2933                 data_ref = btrfs_delayed_node_to_data_ref(ref);
2934
2935                 /*
2936                  * If our ref doesn't match the one we're currently looking at
2937                  * then we have a cross reference.
2938                  */
2939                 if (data_ref->root != root->root_key.objectid ||
2940                     data_ref->objectid != objectid ||
2941                     data_ref->offset != offset) {
2942                         ret = 1;
2943                         break;
2944                 }
2945         }
2946         spin_unlock(&head->lock);
2947         mutex_unlock(&head->mutex);
2948         return ret;
2949 }
2950
2951 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2952                                         struct btrfs_root *root,
2953                                         struct btrfs_path *path,
2954                                         u64 objectid, u64 offset, u64 bytenr)
2955 {
2956         struct btrfs_root *extent_root = root->fs_info->extent_root;
2957         struct extent_buffer *leaf;
2958         struct btrfs_extent_data_ref *ref;
2959         struct btrfs_extent_inline_ref *iref;
2960         struct btrfs_extent_item *ei;
2961         struct btrfs_key key;
2962         u32 item_size;
2963         int ret;
2964
2965         key.objectid = bytenr;
2966         key.offset = (u64)-1;
2967         key.type = BTRFS_EXTENT_ITEM_KEY;
2968
2969         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2970         if (ret < 0)
2971                 goto out;
2972         BUG_ON(ret == 0); /* Corruption */
2973
2974         ret = -ENOENT;
2975         if (path->slots[0] == 0)
2976                 goto out;
2977
2978         path->slots[0]--;
2979         leaf = path->nodes[0];
2980         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2981
2982         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2983                 goto out;
2984
2985         ret = 1;
2986         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2987 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2988         if (item_size < sizeof(*ei)) {
2989                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2990                 goto out;
2991         }
2992 #endif
2993         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2994
2995         if (item_size != sizeof(*ei) +
2996             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2997                 goto out;
2998
2999         if (btrfs_extent_generation(leaf, ei) <=
3000             btrfs_root_last_snapshot(&root->root_item))
3001                 goto out;
3002
3003         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3004         if (btrfs_extent_inline_ref_type(leaf, iref) !=
3005             BTRFS_EXTENT_DATA_REF_KEY)
3006                 goto out;
3007
3008         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3009         if (btrfs_extent_refs(leaf, ei) !=
3010             btrfs_extent_data_ref_count(leaf, ref) ||
3011             btrfs_extent_data_ref_root(leaf, ref) !=
3012             root->root_key.objectid ||
3013             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3014             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3015                 goto out;
3016
3017         ret = 0;
3018 out:
3019         return ret;
3020 }
3021
3022 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3023                           struct btrfs_root *root,
3024                           u64 objectid, u64 offset, u64 bytenr)
3025 {
3026         struct btrfs_path *path;
3027         int ret;
3028         int ret2;
3029
3030         path = btrfs_alloc_path();
3031         if (!path)
3032                 return -ENOENT;
3033
3034         do {
3035                 ret = check_committed_ref(trans, root, path, objectid,
3036                                           offset, bytenr);
3037                 if (ret && ret != -ENOENT)
3038                         goto out;
3039
3040                 ret2 = check_delayed_ref(trans, root, path, objectid,
3041                                          offset, bytenr);
3042         } while (ret2 == -EAGAIN);
3043
3044         if (ret2 && ret2 != -ENOENT) {
3045                 ret = ret2;
3046                 goto out;
3047         }
3048
3049         if (ret != -ENOENT || ret2 != -ENOENT)
3050                 ret = 0;
3051 out:
3052         btrfs_free_path(path);
3053         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3054                 WARN_ON(ret > 0);
3055         return ret;
3056 }
3057
3058 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3059                            struct btrfs_root *root,
3060                            struct extent_buffer *buf,
3061                            int full_backref, int inc)
3062 {
3063         u64 bytenr;
3064         u64 num_bytes;
3065         u64 parent;
3066         u64 ref_root;
3067         u32 nritems;
3068         struct btrfs_key key;
3069         struct btrfs_file_extent_item *fi;
3070         int i;
3071         int level;
3072         int ret = 0;
3073         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3074                             u64, u64, u64, u64, u64, u64, int);
3075
3076 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3077         if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state)))
3078                 return 0;
3079 #endif
3080         ref_root = btrfs_header_owner(buf);
3081         nritems = btrfs_header_nritems(buf);
3082         level = btrfs_header_level(buf);
3083
3084         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3085                 return 0;
3086
3087         if (inc)
3088                 process_func = btrfs_inc_extent_ref;
3089         else
3090                 process_func = btrfs_free_extent;
3091
3092         if (full_backref)
3093                 parent = buf->start;
3094         else
3095                 parent = 0;
3096
3097         for (i = 0; i < nritems; i++) {
3098                 if (level == 0) {
3099                         btrfs_item_key_to_cpu(buf, &key, i);
3100                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3101                                 continue;
3102                         fi = btrfs_item_ptr(buf, i,
3103                                             struct btrfs_file_extent_item);
3104                         if (btrfs_file_extent_type(buf, fi) ==
3105                             BTRFS_FILE_EXTENT_INLINE)
3106                                 continue;
3107                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3108                         if (bytenr == 0)
3109                                 continue;
3110
3111                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3112                         key.offset -= btrfs_file_extent_offset(buf, fi);
3113                         ret = process_func(trans, root, bytenr, num_bytes,
3114                                            parent, ref_root, key.objectid,
3115                                            key.offset, 1);
3116                         if (ret)
3117                                 goto fail;
3118                 } else {
3119                         bytenr = btrfs_node_blockptr(buf, i);
3120                         num_bytes = btrfs_level_size(root, level - 1);
3121                         ret = process_func(trans, root, bytenr, num_bytes,
3122                                            parent, ref_root, level - 1, 0,
3123                                            1);
3124                         if (ret)
3125                                 goto fail;
3126                 }
3127         }
3128         return 0;
3129 fail:
3130         return ret;
3131 }
3132
3133 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3134                   struct extent_buffer *buf, int full_backref)
3135 {
3136         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3137 }
3138
3139 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3140                   struct extent_buffer *buf, int full_backref)
3141 {
3142         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3143 }
3144
3145 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3146                                  struct btrfs_root *root,
3147                                  struct btrfs_path *path,
3148                                  struct btrfs_block_group_cache *cache)
3149 {
3150         int ret;
3151         struct btrfs_root *extent_root = root->fs_info->extent_root;
3152         unsigned long bi;
3153         struct extent_buffer *leaf;
3154
3155         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3156         if (ret < 0)
3157                 goto fail;
3158         BUG_ON(ret); /* Corruption */
3159
3160         leaf = path->nodes[0];
3161         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3162         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3163         btrfs_mark_buffer_dirty(leaf);
3164         btrfs_release_path(path);
3165 fail:
3166         if (ret) {
3167                 btrfs_abort_transaction(trans, root, ret);
3168                 return ret;
3169         }
3170         return 0;
3171
3172 }
3173
3174 static struct btrfs_block_group_cache *
3175 next_block_group(struct btrfs_root *root,
3176                  struct btrfs_block_group_cache *cache)
3177 {
3178         struct rb_node *node;
3179         spin_lock(&root->fs_info->block_group_cache_lock);
3180         node = rb_next(&cache->cache_node);
3181         btrfs_put_block_group(cache);
3182         if (node) {
3183                 cache = rb_entry(node, struct btrfs_block_group_cache,
3184                                  cache_node);
3185                 btrfs_get_block_group(cache);
3186         } else
3187                 cache = NULL;
3188         spin_unlock(&root->fs_info->block_group_cache_lock);
3189         return cache;
3190 }
3191
3192 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3193                             struct btrfs_trans_handle *trans,
3194                             struct btrfs_path *path)
3195 {
3196         struct btrfs_root *root = block_group->fs_info->tree_root;
3197         struct inode *inode = NULL;
3198         u64 alloc_hint = 0;
3199         int dcs = BTRFS_DC_ERROR;
3200         int num_pages = 0;
3201         int retries = 0;
3202         int ret = 0;
3203
3204         /*
3205          * If this block group is smaller than 100 megs don't bother caching the
3206          * block group.
3207          */
3208         if (block_group->key.offset < (100 * 1024 * 1024)) {
3209                 spin_lock(&block_group->lock);
3210                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3211                 spin_unlock(&block_group->lock);
3212                 return 0;
3213         }
3214
3215 again:
3216         inode = lookup_free_space_inode(root, block_group, path);
3217         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3218                 ret = PTR_ERR(inode);
3219                 btrfs_release_path(path);
3220                 goto out;
3221         }
3222
3223         if (IS_ERR(inode)) {
3224                 BUG_ON(retries);
3225                 retries++;
3226
3227                 if (block_group->ro)
3228                         goto out_free;
3229
3230                 ret = create_free_space_inode(root, trans, block_group, path);
3231                 if (ret)
3232                         goto out_free;
3233                 goto again;
3234         }
3235
3236         /* We've already setup this transaction, go ahead and exit */
3237         if (block_group->cache_generation == trans->transid &&
3238             i_size_read(inode)) {
3239                 dcs = BTRFS_DC_SETUP;
3240                 goto out_put;
3241         }
3242
3243         /*
3244          * We want to set the generation to 0, that way if anything goes wrong
3245          * from here on out we know not to trust this cache when we load up next
3246          * time.
3247          */
3248         BTRFS_I(inode)->generation = 0;
3249         ret = btrfs_update_inode(trans, root, inode);
3250         WARN_ON(ret);
3251
3252         if (i_size_read(inode) > 0) {
3253                 ret = btrfs_check_trunc_cache_free_space(root,
3254                                         &root->fs_info->global_block_rsv);
3255                 if (ret)
3256                         goto out_put;
3257
3258                 ret = btrfs_truncate_free_space_cache(root, trans, inode);
3259                 if (ret)
3260                         goto out_put;
3261         }
3262
3263         spin_lock(&block_group->lock);
3264         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3265             !btrfs_test_opt(root, SPACE_CACHE) ||
3266             block_group->delalloc_bytes) {
3267                 /*
3268                  * don't bother trying to write stuff out _if_
3269                  * a) we're not cached,
3270                  * b) we're with nospace_cache mount option.
3271                  */
3272                 dcs = BTRFS_DC_WRITTEN;
3273                 spin_unlock(&block_group->lock);
3274                 goto out_put;
3275         }
3276         spin_unlock(&block_group->lock);
3277
3278         /*
3279          * Try to preallocate enough space based on how big the block group is.
3280          * Keep in mind this has to include any pinned space which could end up
3281          * taking up quite a bit since it's not folded into the other space
3282          * cache.
3283          */
3284         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3285         if (!num_pages)
3286                 num_pages = 1;
3287
3288         num_pages *= 16;
3289         num_pages *= PAGE_CACHE_SIZE;
3290
3291         ret = btrfs_check_data_free_space(inode, num_pages);
3292         if (ret)
3293                 goto out_put;
3294
3295         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3296                                               num_pages, num_pages,
3297                                               &alloc_hint);
3298         if (!ret)
3299                 dcs = BTRFS_DC_SETUP;
3300         btrfs_free_reserved_data_space(inode, num_pages);
3301
3302 out_put:
3303         iput(inode);
3304 out_free:
3305         btrfs_release_path(path);
3306 out:
3307         spin_lock(&block_group->lock);
3308         if (!ret && dcs == BTRFS_DC_SETUP)
3309                 block_group->cache_generation = trans->transid;
3310         block_group->disk_cache_state = dcs;
3311         spin_unlock(&block_group->lock);
3312
3313         return ret;
3314 }
3315
3316 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3317                                    struct btrfs_root *root)
3318 {
3319         struct btrfs_block_group_cache *cache;
3320         int err = 0;
3321         struct btrfs_path *path;
3322         u64 last = 0;
3323
3324         path = btrfs_alloc_path();
3325         if (!path)
3326                 return -ENOMEM;
3327
3328 again:
3329         while (1) {
3330                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3331                 while (cache) {
3332                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3333                                 break;
3334                         cache = next_block_group(root, cache);
3335                 }
3336                 if (!cache) {
3337                         if (last == 0)
3338                                 break;
3339                         last = 0;
3340                         continue;
3341                 }
3342                 err = cache_save_setup(cache, trans, path);
3343                 last = cache->key.objectid + cache->key.offset;
3344                 btrfs_put_block_group(cache);
3345         }
3346
3347         while (1) {
3348                 if (last == 0) {
3349                         err = btrfs_run_delayed_refs(trans, root,
3350                                                      (unsigned long)-1);
3351                         if (err) /* File system offline */
3352                                 goto out;
3353                 }
3354
3355                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3356                 while (cache) {
3357                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3358                                 btrfs_put_block_group(cache);
3359                                 goto again;
3360                         }
3361
3362                         if (cache->dirty)
3363                                 break;
3364                         cache = next_block_group(root, cache);
3365                 }
3366                 if (!cache) {
3367                         if (last == 0)
3368                                 break;
3369                         last = 0;
3370                         continue;
3371                 }
3372
3373                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3374                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3375                 cache->dirty = 0;
3376                 last = cache->key.objectid + cache->key.offset;
3377
3378                 err = write_one_cache_group(trans, root, path, cache);
3379                 btrfs_put_block_group(cache);
3380                 if (err) /* File system offline */
3381                         goto out;
3382         }
3383
3384         while (1) {
3385                 /*
3386                  * I don't think this is needed since we're just marking our
3387                  * preallocated extent as written, but just in case it can't
3388                  * hurt.
3389                  */
3390                 if (last == 0) {
3391                         err = btrfs_run_delayed_refs(trans, root,
3392                                                      (unsigned long)-1);
3393                         if (err) /* File system offline */
3394                                 goto out;
3395                 }
3396
3397                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3398                 while (cache) {
3399                         /*
3400                          * Really this shouldn't happen, but it could if we
3401                          * couldn't write the entire preallocated extent and
3402                          * splitting the extent resulted in a new block.
3403                          */
3404                         if (cache->dirty) {
3405                                 btrfs_put_block_group(cache);
3406                                 goto again;
3407                         }
3408                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3409                                 break;
3410                         cache = next_block_group(root, cache);
3411                 }
3412                 if (!cache) {
3413                         if (last == 0)
3414                                 break;
3415                         last = 0;
3416                         continue;
3417                 }
3418
3419                 err = btrfs_write_out_cache(root, trans, cache, path);
3420
3421                 /*
3422                  * If we didn't have an error then the cache state is still
3423                  * NEED_WRITE, so we can set it to WRITTEN.
3424                  */
3425                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3426                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3427                 last = cache->key.objectid + cache->key.offset;
3428                 btrfs_put_block_group(cache);
3429         }
3430 out:
3431
3432         btrfs_free_path(path);
3433         return err;
3434 }
3435
3436 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3437 {
3438         struct btrfs_block_group_cache *block_group;
3439         int readonly = 0;
3440
3441         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3442         if (!block_group || block_group->ro)
3443                 readonly = 1;
3444         if (block_group)
3445                 btrfs_put_block_group(block_group);
3446         return readonly;
3447 }
3448
3449 static const char *alloc_name(u64 flags)
3450 {
3451         switch (flags) {
3452         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3453                 return "mixed";
3454         case BTRFS_BLOCK_GROUP_METADATA:
3455                 return "metadata";
3456         case BTRFS_BLOCK_GROUP_DATA:
3457                 return "data";
3458         case BTRFS_BLOCK_GROUP_SYSTEM:
3459                 return "system";
3460         default:
3461                 WARN_ON(1);
3462                 return "invalid-combination";
3463         };
3464 }
3465
3466 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3467                              u64 total_bytes, u64 bytes_used,
3468                              struct btrfs_space_info **space_info)
3469 {
3470         struct btrfs_space_info *found;
3471         int i;
3472         int factor;
3473         int ret;
3474
3475         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3476                      BTRFS_BLOCK_GROUP_RAID10))
3477                 factor = 2;
3478         else
3479                 factor = 1;
3480
3481         found = __find_space_info(info, flags);
3482         if (found) {
3483                 spin_lock(&found->lock);
3484                 found->total_bytes += total_bytes;
3485                 found->disk_total += total_bytes * factor;
3486                 found->bytes_used += bytes_used;
3487                 found->disk_used += bytes_used * factor;
3488                 found->full = 0;
3489                 spin_unlock(&found->lock);
3490                 *space_info = found;
3491                 return 0;
3492         }
3493         found = kzalloc(sizeof(*found), GFP_NOFS);
3494         if (!found)
3495                 return -ENOMEM;
3496
3497         ret = percpu_counter_init(&found->total_bytes_pinned, 0);
3498         if (ret) {
3499                 kfree(found);
3500                 return ret;
3501         }
3502
3503         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3504                 INIT_LIST_HEAD(&found->block_groups[i]);
3505         init_rwsem(&found->groups_sem);
3506         spin_lock_init(&found->lock);
3507         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3508         found->total_bytes = total_bytes;
3509         found->disk_total = total_bytes * factor;
3510         found->bytes_used = bytes_used;
3511         found->disk_used = bytes_used * factor;
3512         found->bytes_pinned = 0;
3513         found->bytes_reserved = 0;
3514         found->bytes_readonly = 0;
3515         found->bytes_may_use = 0;
3516         found->full = 0;
3517         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3518         found->chunk_alloc = 0;
3519         found->flush = 0;
3520         init_waitqueue_head(&found->wait);
3521
3522         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3523                                     info->space_info_kobj, "%s",
3524                                     alloc_name(found->flags));
3525         if (ret) {
3526                 kfree(found);
3527                 return ret;
3528         }
3529
3530         *space_info = found;
3531         list_add_rcu(&found->list, &info->space_info);
3532         if (flags & BTRFS_BLOCK_GROUP_DATA)
3533                 info->data_sinfo = found;
3534
3535         return ret;
3536 }
3537
3538 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3539 {
3540         u64 extra_flags = chunk_to_extended(flags) &
3541                                 BTRFS_EXTENDED_PROFILE_MASK;
3542
3543         write_seqlock(&fs_info->profiles_lock);
3544         if (flags & BTRFS_BLOCK_GROUP_DATA)
3545                 fs_info->avail_data_alloc_bits |= extra_flags;
3546         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3547                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3548         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3549                 fs_info->avail_system_alloc_bits |= extra_flags;
3550         write_sequnlock(&fs_info->profiles_lock);
3551 }
3552
3553 /*
3554  * returns target flags in extended format or 0 if restripe for this
3555  * chunk_type is not in progress
3556  *
3557  * should be called with either volume_mutex or balance_lock held
3558  */
3559 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3560 {
3561         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3562         u64 target = 0;
3563
3564         if (!bctl)
3565                 return 0;
3566
3567         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3568             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3569                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3570         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3571                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3572                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3573         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3574                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3575                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3576         }
3577
3578         return target;
3579 }
3580
3581 /*
3582  * @flags: available profiles in extended format (see ctree.h)
3583  *
3584  * Returns reduced profile in chunk format.  If profile changing is in
3585  * progress (either running or paused) picks the target profile (if it's
3586  * already available), otherwise falls back to plain reducing.
3587  */
3588 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3589 {
3590         u64 num_devices = root->fs_info->fs_devices->rw_devices;
3591         u64 target;
3592         u64 tmp;
3593
3594         /*
3595          * see if restripe for this chunk_type is in progress, if so
3596          * try to reduce to the target profile
3597          */
3598         spin_lock(&root->fs_info->balance_lock);
3599         target = get_restripe_target(root->fs_info, flags);
3600         if (target) {
3601                 /* pick target profile only if it's already available */
3602                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3603                         spin_unlock(&root->fs_info->balance_lock);
3604                         return extended_to_chunk(target);
3605                 }
3606         }
3607         spin_unlock(&root->fs_info->balance_lock);
3608
3609         /* First, mask out the RAID levels which aren't possible */
3610         if (num_devices == 1)
3611                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3612                            BTRFS_BLOCK_GROUP_RAID5);
3613         if (num_devices < 3)
3614                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3615         if (num_devices < 4)
3616                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3617
3618         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3619                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3620                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3621         flags &= ~tmp;
3622
3623         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3624                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3625         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3626                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3627         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3628                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3629         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3630                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3631         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3632                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3633
3634         return extended_to_chunk(flags | tmp);
3635 }
3636
3637 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
3638 {
3639         unsigned seq;
3640         u64 flags;
3641
3642         do {
3643                 flags = orig_flags;
3644                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3645
3646                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3647                         flags |= root->fs_info->avail_data_alloc_bits;
3648                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3649                         flags |= root->fs_info->avail_system_alloc_bits;
3650                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3651                         flags |= root->fs_info->avail_metadata_alloc_bits;
3652         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3653
3654         return btrfs_reduce_alloc_profile(root, flags);
3655 }
3656
3657 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3658 {
3659         u64 flags;
3660         u64 ret;
3661
3662         if (data)
3663                 flags = BTRFS_BLOCK_GROUP_DATA;
3664         else if (root == root->fs_info->chunk_root)
3665                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3666         else
3667                 flags = BTRFS_BLOCK_GROUP_METADATA;
3668
3669         ret = get_alloc_profile(root, flags);
3670         return ret;
3671 }
3672
3673 /*
3674  * This will check the space that the inode allocates from to make sure we have
3675  * enough space for bytes.
3676  */
3677 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3678 {
3679         struct btrfs_space_info *data_sinfo;
3680         struct btrfs_root *root = BTRFS_I(inode)->root;
3681         struct btrfs_fs_info *fs_info = root->fs_info;
3682         u64 used;
3683         int ret = 0, committed = 0, alloc_chunk = 1;
3684
3685         /* make sure bytes are sectorsize aligned */
3686         bytes = ALIGN(bytes, root->sectorsize);
3687
3688         if (btrfs_is_free_space_inode(inode)) {
3689                 committed = 1;
3690                 ASSERT(current->journal_info);
3691         }
3692
3693         data_sinfo = fs_info->data_sinfo;
3694         if (!data_sinfo)
3695                 goto alloc;
3696
3697 again:
3698         /* make sure we have enough space to handle the data first */
3699         spin_lock(&data_sinfo->lock);
3700         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3701                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3702                 data_sinfo->bytes_may_use;
3703
3704         if (used + bytes > data_sinfo->total_bytes) {
3705                 struct btrfs_trans_handle *trans;
3706
3707                 /*
3708                  * if we don't have enough free bytes in this space then we need
3709                  * to alloc a new chunk.
3710                  */
3711                 if (!data_sinfo->full && alloc_chunk) {
3712                         u64 alloc_target;
3713
3714                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3715                         spin_unlock(&data_sinfo->lock);
3716 alloc:
3717                         alloc_target = btrfs_get_alloc_profile(root, 1);
3718                         /*
3719                          * It is ugly that we don't call nolock join
3720                          * transaction for the free space inode case here.
3721                          * But it is safe because we only do the data space
3722                          * reservation for the free space cache in the
3723                          * transaction context, the common join transaction
3724                          * just increase the counter of the current transaction
3725                          * handler, doesn't try to acquire the trans_lock of
3726                          * the fs.
3727                          */
3728                         trans = btrfs_join_transaction(root);
3729                         if (IS_ERR(trans))
3730                                 return PTR_ERR(trans);
3731
3732                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3733                                              alloc_target,
3734                                              CHUNK_ALLOC_NO_FORCE);
3735                         btrfs_end_transaction(trans, root);
3736                         if (ret < 0) {
3737                                 if (ret != -ENOSPC)
3738                                         return ret;
3739                                 else
3740                                         goto commit_trans;
3741                         }
3742
3743                         if (!data_sinfo)
3744                                 data_sinfo = fs_info->data_sinfo;
3745
3746                         goto again;
3747                 }
3748
3749                 /*
3750                  * If we don't have enough pinned space to deal with this
3751                  * allocation don't bother committing the transaction.
3752                  */
3753                 if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
3754                                            bytes) < 0)
3755                         committed = 1;
3756                 spin_unlock(&data_sinfo->lock);
3757
3758                 /* commit the current transaction and try again */
3759 commit_trans:
3760                 if (!committed &&
3761                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3762                         committed = 1;
3763
3764                         trans = btrfs_join_transaction(root);
3765                         if (IS_ERR(trans))
3766                                 return PTR_ERR(trans);
3767                         ret = btrfs_commit_transaction(trans, root);
3768                         if (ret)
3769                                 return ret;
3770                         goto again;
3771                 }
3772
3773                 trace_btrfs_space_reservation(root->fs_info,
3774                                               "space_info:enospc",
3775                                               data_sinfo->flags, bytes, 1);
3776                 return -ENOSPC;
3777         }
3778         data_sinfo->bytes_may_use += bytes;
3779         trace_btrfs_space_reservation(root->fs_info, "space_info",
3780                                       data_sinfo->flags, bytes, 1);
3781         spin_unlock(&data_sinfo->lock);
3782
3783         return 0;
3784 }
3785
3786 /*
3787  * Called if we need to clear a data reservation for this inode.
3788  */
3789 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3790 {
3791         struct btrfs_root *root = BTRFS_I(inode)->root;
3792         struct btrfs_space_info *data_sinfo;
3793
3794         /* make sure bytes are sectorsize aligned */
3795         bytes = ALIGN(bytes, root->sectorsize);
3796
3797         data_sinfo = root->fs_info->data_sinfo;
3798         spin_lock(&data_sinfo->lock);
3799         WARN_ON(data_sinfo->bytes_may_use < bytes);
3800         data_sinfo->bytes_may_use -= bytes;
3801         trace_btrfs_space_reservation(root->fs_info, "space_info",
3802                                       data_sinfo->flags, bytes, 0);
3803         spin_unlock(&data_sinfo->lock);
3804 }
3805
3806 static void force_metadata_allocation(struct btrfs_fs_info *info)
3807 {
3808         struct list_head *head = &info->space_info;
3809         struct btrfs_space_info *found;
3810
3811         rcu_read_lock();
3812         list_for_each_entry_rcu(found, head, list) {
3813                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3814                         found->force_alloc = CHUNK_ALLOC_FORCE;
3815         }
3816         rcu_read_unlock();
3817 }
3818
3819 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3820 {
3821         return (global->size << 1);
3822 }
3823
3824 static int should_alloc_chunk(struct btrfs_root *root,
3825                               struct btrfs_space_info *sinfo, int force)
3826 {
3827         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3828         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3829         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3830         u64 thresh;
3831
3832         if (force == CHUNK_ALLOC_FORCE)
3833                 return 1;
3834
3835         /*
3836          * We need to take into account the global rsv because for all intents
3837          * and purposes it's used space.  Don't worry about locking the
3838          * global_rsv, it doesn't change except when the transaction commits.
3839          */
3840         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3841                 num_allocated += calc_global_rsv_need_space(global_rsv);
3842
3843         /*
3844          * in limited mode, we want to have some free space up to
3845          * about 1% of the FS size.
3846          */
3847         if (force == CHUNK_ALLOC_LIMITED) {
3848                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3849                 thresh = max_t(u64, 64 * 1024 * 1024,
3850                                div_factor_fine(thresh, 1));
3851
3852                 if (num_bytes - num_allocated < thresh)
3853                         return 1;
3854         }
3855
3856         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3857                 return 0;
3858         return 1;
3859 }
3860
3861 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3862 {
3863         u64 num_dev;
3864
3865         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3866                     BTRFS_BLOCK_GROUP_RAID0 |
3867                     BTRFS_BLOCK_GROUP_RAID5 |
3868                     BTRFS_BLOCK_GROUP_RAID6))
3869                 num_dev = root->fs_info->fs_devices->rw_devices;
3870         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3871                 num_dev = 2;
3872         else
3873                 num_dev = 1;    /* DUP or single */
3874
3875         /* metadata for updaing devices and chunk tree */
3876         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3877 }
3878
3879 static void check_system_chunk(struct btrfs_trans_handle *trans,
3880                                struct btrfs_root *root, u64 type)
3881 {
3882         struct btrfs_space_info *info;
3883         u64 left;
3884         u64 thresh;
3885
3886         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3887         spin_lock(&info->lock);
3888         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3889                 info->bytes_reserved - info->bytes_readonly;
3890         spin_unlock(&info->lock);
3891
3892         thresh = get_system_chunk_thresh(root, type);
3893         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3894                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
3895                         left, thresh, type);
3896                 dump_space_info(info, 0, 0);
3897         }
3898
3899         if (left < thresh) {
3900                 u64 flags;
3901
3902                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3903                 btrfs_alloc_chunk(trans, root, flags);
3904         }
3905 }
3906
3907 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3908                           struct btrfs_root *extent_root, u64 flags, int force)
3909 {
3910         struct btrfs_space_info *space_info;
3911         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3912         int wait_for_alloc = 0;
3913         int ret = 0;
3914
3915         /* Don't re-enter if we're already allocating a chunk */
3916         if (trans->allocating_chunk)
3917                 return -ENOSPC;
3918
3919         space_info = __find_space_info(extent_root->fs_info, flags);
3920         if (!space_info) {
3921                 ret = update_space_info(extent_root->fs_info, flags,
3922                                         0, 0, &space_info);
3923                 BUG_ON(ret); /* -ENOMEM */
3924         }
3925         BUG_ON(!space_info); /* Logic error */
3926
3927 again:
3928         spin_lock(&space_info->lock);
3929         if (force < space_info->force_alloc)
3930                 force = space_info->force_alloc;
3931         if (space_info->full) {
3932                 if (should_alloc_chunk(extent_root, space_info, force))
3933                         ret = -ENOSPC;
3934                 else
3935                         ret = 0;
3936                 spin_unlock(&space_info->lock);
3937                 return ret;
3938         }
3939
3940         if (!should_alloc_chunk(extent_root, space_info, force)) {
3941                 spin_unlock(&space_info->lock);
3942                 return 0;
3943         } else if (space_info->chunk_alloc) {
3944                 wait_for_alloc = 1;
3945         } else {
3946                 space_info->chunk_alloc = 1;
3947         }
3948
3949         spin_unlock(&space_info->lock);
3950
3951         mutex_lock(&fs_info->chunk_mutex);
3952
3953         /*
3954          * The chunk_mutex is held throughout the entirety of a chunk
3955          * allocation, so once we've acquired the chunk_mutex we know that the
3956          * other guy is done and we need to recheck and see if we should
3957          * allocate.
3958          */
3959         if (wait_for_alloc) {
3960                 mutex_unlock(&fs_info->chunk_mutex);
3961                 wait_for_alloc = 0;
3962                 goto again;
3963         }
3964
3965         trans->allocating_chunk = true;
3966
3967         /*
3968          * If we have mixed data/metadata chunks we want to make sure we keep
3969          * allocating mixed chunks instead of individual chunks.
3970          */
3971         if (btrfs_mixed_space_info(space_info))
3972                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3973
3974         /*
3975          * if we're doing a data chunk, go ahead and make sure that
3976          * we keep a reasonable number of metadata chunks allocated in the
3977          * FS as well.
3978          */
3979         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3980                 fs_info->data_chunk_allocations++;
3981                 if (!(fs_info->data_chunk_allocations %
3982                       fs_info->metadata_ratio))
3983                         force_metadata_allocation(fs_info);
3984         }
3985
3986         /*
3987          * Check if we have enough space in SYSTEM chunk because we may need
3988          * to update devices.
3989          */
3990         check_system_chunk(trans, extent_root, flags);
3991
3992         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3993         trans->allocating_chunk = false;
3994
3995         spin_lock(&space_info->lock);
3996         if (ret < 0 && ret != -ENOSPC)
3997                 goto out;
3998         if (ret)
3999                 space_info->full = 1;
4000         else
4001                 ret = 1;
4002
4003         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4004 out:
4005         space_info->chunk_alloc = 0;
4006         spin_unlock(&space_info->lock);
4007         mutex_unlock(&fs_info->chunk_mutex);
4008         return ret;
4009 }
4010
4011 static int can_overcommit(struct btrfs_root *root,
4012                           struct btrfs_space_info *space_info, u64 bytes,
4013                           enum btrfs_reserve_flush_enum flush)
4014 {
4015         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4016         u64 profile = btrfs_get_alloc_profile(root, 0);
4017         u64 space_size;
4018         u64 avail;
4019         u64 used;
4020
4021         used = space_info->bytes_used + space_info->bytes_reserved +
4022                 space_info->bytes_pinned + space_info->bytes_readonly;
4023
4024         /*
4025          * We only want to allow over committing if we have lots of actual space
4026          * free, but if we don't have enough space to handle the global reserve
4027          * space then we could end up having a real enospc problem when trying
4028          * to allocate a chunk or some other such important allocation.
4029          */
4030         spin_lock(&global_rsv->lock);
4031         space_size = calc_global_rsv_need_space(global_rsv);
4032         spin_unlock(&global_rsv->lock);
4033         if (used + space_size >= space_info->total_bytes)
4034                 return 0;
4035
4036         used += space_info->bytes_may_use;
4037
4038         spin_lock(&root->fs_info->free_chunk_lock);
4039         avail = root->fs_info->free_chunk_space;
4040         spin_unlock(&root->fs_info->free_chunk_lock);
4041
4042         /*
4043          * If we have dup, raid1 or raid10 then only half of the free
4044          * space is actually useable.  For raid56, the space info used
4045          * doesn't include the parity drive, so we don't have to
4046          * change the math
4047          */
4048         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4049                        BTRFS_BLOCK_GROUP_RAID1 |
4050                        BTRFS_BLOCK_GROUP_RAID10))
4051                 avail >>= 1;
4052
4053         /*
4054          * If we aren't flushing all things, let us overcommit up to
4055          * 1/2th of the space. If we can flush, don't let us overcommit
4056          * too much, let it overcommit up to 1/8 of the space.
4057          */
4058         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4059                 avail >>= 3;
4060         else
4061                 avail >>= 1;
4062
4063         if (used + bytes < space_info->total_bytes + avail)
4064                 return 1;
4065         return 0;
4066 }
4067
4068 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4069                                          unsigned long nr_pages, int nr_items)
4070 {
4071         struct super_block *sb = root->fs_info->sb;
4072
4073         if (down_read_trylock(&sb->s_umount)) {
4074                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4075                 up_read(&sb->s_umount);
4076         } else {
4077                 /*
4078                  * We needn't worry the filesystem going from r/w to r/o though
4079                  * we don't acquire ->s_umount mutex, because the filesystem
4080                  * should guarantee the delalloc inodes list be empty after
4081                  * the filesystem is readonly(all dirty pages are written to
4082                  * the disk).
4083                  */
4084                 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4085                 if (!current->journal_info)
4086                         btrfs_wait_ordered_roots(root->fs_info, nr_items);
4087         }
4088 }
4089
4090 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4091 {
4092         u64 bytes;
4093         int nr;
4094
4095         bytes = btrfs_calc_trans_metadata_size(root, 1);
4096         nr = (int)div64_u64(to_reclaim, bytes);
4097         if (!nr)
4098                 nr = 1;
4099         return nr;
4100 }
4101
4102 #define EXTENT_SIZE_PER_ITEM    (256 * 1024)
4103
4104 /*
4105  * shrink metadata reservation for delalloc
4106  */
4107 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4108                             bool wait_ordered)
4109 {
4110         struct btrfs_block_rsv *block_rsv;
4111         struct btrfs_space_info *space_info;
4112         struct btrfs_trans_handle *trans;
4113         u64 delalloc_bytes;
4114         u64 max_reclaim;
4115         long time_left;
4116         unsigned long nr_pages;
4117         int loops;
4118         int items;
4119         enum btrfs_reserve_flush_enum flush;
4120
4121         /* Calc the number of the pages we need flush for space reservation */
4122         items = calc_reclaim_items_nr(root, to_reclaim);
4123         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4124
4125         trans = (struct btrfs_trans_handle *)current->journal_info;
4126         block_rsv = &root->fs_info->delalloc_block_rsv;
4127         space_info = block_rsv->space_info;
4128
4129         delalloc_bytes = percpu_counter_sum_positive(
4130                                                 &root->fs_info->delalloc_bytes);
4131         if (delalloc_bytes == 0) {
4132                 if (trans)
4133                         return;
4134                 if (wait_ordered)
4135                         btrfs_wait_ordered_roots(root->fs_info, items);
4136                 return;
4137         }
4138
4139         loops = 0;
4140         while (delalloc_bytes && loops < 3) {
4141                 max_reclaim = min(delalloc_bytes, to_reclaim);
4142                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4143                 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4144                 /*
4145                  * We need to wait for the async pages to actually start before
4146                  * we do anything.
4147                  */
4148                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4149                 if (!max_reclaim)
4150                         goto skip_async;
4151
4152                 if (max_reclaim <= nr_pages)
4153                         max_reclaim = 0;
4154                 else
4155                         max_reclaim -= nr_pages;
4156
4157                 wait_event(root->fs_info->async_submit_wait,
4158                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4159                            (int)max_reclaim);
4160 skip_async:
4161                 if (!trans)
4162                         flush = BTRFS_RESERVE_FLUSH_ALL;
4163                 else
4164                         flush = BTRFS_RESERVE_NO_FLUSH;
4165                 spin_lock(&space_info->lock);
4166                 if (can_overcommit(root, space_info, orig, flush)) {
4167                         spin_unlock(&space_info->lock);
4168                         break;
4169                 }
4170                 spin_unlock(&space_info->lock);
4171
4172                 loops++;
4173                 if (wait_ordered && !trans) {
4174                         btrfs_wait_ordered_roots(root->fs_info, items);
4175                 } else {
4176                         time_left = schedule_timeout_killable(1);
4177                         if (time_left)
4178                                 break;
4179                 }
4180                 delalloc_bytes = percpu_counter_sum_positive(
4181                                                 &root->fs_info->delalloc_bytes);
4182         }
4183 }
4184
4185 /**
4186  * maybe_commit_transaction - possibly commit the transaction if its ok to
4187  * @root - the root we're allocating for
4188  * @bytes - the number of bytes we want to reserve
4189  * @force - force the commit
4190  *
4191  * This will check to make sure that committing the transaction will actually
4192  * get us somewhere and then commit the transaction if it does.  Otherwise it
4193  * will return -ENOSPC.
4194  */
4195 static int may_commit_transaction(struct btrfs_root *root,
4196                                   struct btrfs_space_info *space_info,
4197                                   u64 bytes, int force)
4198 {
4199         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4200         struct btrfs_trans_handle *trans;
4201
4202         trans = (struct btrfs_trans_handle *)current->journal_info;
4203         if (trans)
4204                 return -EAGAIN;
4205
4206         if (force)
4207                 goto commit;
4208
4209         /* See if there is enough pinned space to make this reservation */
4210         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4211                                    bytes) >= 0)
4212                 goto commit;
4213
4214         /*
4215          * See if there is some space in the delayed insertion reservation for
4216          * this reservation.
4217          */
4218         if (space_info != delayed_rsv->space_info)
4219                 return -ENOSPC;
4220
4221         spin_lock(&delayed_rsv->lock);
4222         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4223                                    bytes - delayed_rsv->size) >= 0) {
4224                 spin_unlock(&delayed_rsv->lock);
4225                 return -ENOSPC;
4226         }
4227         spin_unlock(&delayed_rsv->lock);
4228
4229 commit:
4230         trans = btrfs_join_transaction(root);
4231         if (IS_ERR(trans))
4232                 return -ENOSPC;
4233
4234         return btrfs_commit_transaction(trans, root);
4235 }
4236
4237 enum flush_state {
4238         FLUSH_DELAYED_ITEMS_NR  =       1,
4239         FLUSH_DELAYED_ITEMS     =       2,
4240         FLUSH_DELALLOC          =       3,
4241         FLUSH_DELALLOC_WAIT     =       4,
4242         ALLOC_CHUNK             =       5,
4243         COMMIT_TRANS            =       6,
4244 };
4245
4246 static int flush_space(struct btrfs_root *root,
4247                        struct btrfs_space_info *space_info, u64 num_bytes,
4248                        u64 orig_bytes, int state)
4249 {
4250         struct btrfs_trans_handle *trans;
4251         int nr;
4252         int ret = 0;
4253
4254         switch (state) {
4255         case FLUSH_DELAYED_ITEMS_NR:
4256         case FLUSH_DELAYED_ITEMS:
4257                 if (state == FLUSH_DELAYED_ITEMS_NR)
4258                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4259                 else
4260                         nr = -1;
4261
4262                 trans = btrfs_join_transaction(root);
4263                 if (IS_ERR(trans)) {
4264                         ret = PTR_ERR(trans);
4265                         break;
4266                 }
4267                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4268                 btrfs_end_transaction(trans, root);
4269                 break;
4270         case FLUSH_DELALLOC:
4271         case FLUSH_DELALLOC_WAIT:
4272                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4273                                 state == FLUSH_DELALLOC_WAIT);
4274                 break;
4275         case ALLOC_CHUNK:
4276                 trans = btrfs_join_transaction(root);
4277                 if (IS_ERR(trans)) {
4278                         ret = PTR_ERR(trans);
4279                         break;
4280                 }
4281                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4282                                      btrfs_get_alloc_profile(root, 0),
4283                                      CHUNK_ALLOC_NO_FORCE);
4284                 btrfs_end_transaction(trans, root);
4285                 if (ret == -ENOSPC)
4286                         ret = 0;
4287                 break;
4288         case COMMIT_TRANS:
4289                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4290                 break;
4291         default:
4292                 ret = -ENOSPC;
4293                 break;
4294         }
4295
4296         return ret;
4297 }
4298
4299 static inline u64
4300 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4301                                  struct btrfs_space_info *space_info)
4302 {
4303         u64 used;
4304         u64 expected;
4305         u64 to_reclaim;
4306
4307         to_reclaim = min_t(u64, num_online_cpus() * 1024 * 1024,
4308                                 16 * 1024 * 1024);
4309         spin_lock(&space_info->lock);
4310         if (can_overcommit(root, space_info, to_reclaim,
4311                            BTRFS_RESERVE_FLUSH_ALL)) {
4312                 to_reclaim = 0;
4313                 goto out;
4314         }
4315
4316         used = space_info->bytes_used + space_info->bytes_reserved +
4317                space_info->bytes_pinned + space_info->bytes_readonly +
4318                space_info->bytes_may_use;
4319         if (can_overcommit(root, space_info, 1024 * 1024,
4320                            BTRFS_RESERVE_FLUSH_ALL))
4321                 expected = div_factor_fine(space_info->total_bytes, 95);
4322         else
4323                 expected = div_factor_fine(space_info->total_bytes, 90);
4324
4325         if (used > expected)
4326                 to_reclaim = used - expected;
4327         else
4328                 to_reclaim = 0;
4329         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4330                                      space_info->bytes_reserved);
4331 out:
4332         spin_unlock(&space_info->lock);
4333
4334         return to_reclaim;
4335 }
4336
4337 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4338                                         struct btrfs_fs_info *fs_info, u64 used)
4339 {
4340         return (used >= div_factor_fine(space_info->total_bytes, 98) &&
4341                 !btrfs_fs_closing(fs_info) &&
4342                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4343 }
4344
4345 static int btrfs_need_do_async_reclaim(struct btrfs_space_info *space_info,
4346                                        struct btrfs_fs_info *fs_info)
4347 {
4348         u64 used;
4349
4350         spin_lock(&space_info->lock);
4351         used = space_info->bytes_used + space_info->bytes_reserved +
4352                space_info->bytes_pinned + space_info->bytes_readonly +
4353                space_info->bytes_may_use;
4354         if (need_do_async_reclaim(space_info, fs_info, used)) {
4355                 spin_unlock(&space_info->lock);
4356                 return 1;
4357         }
4358         spin_unlock(&space_info->lock);
4359
4360         return 0;
4361 }
4362
4363 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4364 {
4365         struct btrfs_fs_info *fs_info;
4366         struct btrfs_space_info *space_info;
4367         u64 to_reclaim;
4368         int flush_state;
4369
4370         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4371         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4372
4373         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4374                                                       space_info);
4375         if (!to_reclaim)
4376                 return;
4377
4378         flush_state = FLUSH_DELAYED_ITEMS_NR;
4379         do {
4380                 flush_space(fs_info->fs_root, space_info, to_reclaim,
4381                             to_reclaim, flush_state);
4382                 flush_state++;
4383                 if (!btrfs_need_do_async_reclaim(space_info, fs_info))
4384                         return;
4385         } while (flush_state <= COMMIT_TRANS);
4386
4387         if (btrfs_need_do_async_reclaim(space_info, fs_info))
4388                 queue_work(system_unbound_wq, work);
4389 }
4390
4391 void btrfs_init_async_reclaim_work(struct work_struct *work)
4392 {
4393         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
4394 }
4395
4396 /**
4397  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4398  * @root - the root we're allocating for
4399  * @block_rsv - the block_rsv we're allocating for
4400  * @orig_bytes - the number of bytes we want
4401  * @flush - whether or not we can flush to make our reservation
4402  *
4403  * This will reserve orgi_bytes number of bytes from the space info associated
4404  * with the block_rsv.  If there is not enough space it will make an attempt to
4405  * flush out space to make room.  It will do this by flushing delalloc if
4406  * possible or committing the transaction.  If flush is 0 then no attempts to
4407  * regain reservations will be made and this will fail if there is not enough
4408  * space already.
4409  */
4410 static int reserve_metadata_bytes(struct btrfs_root *root,
4411                                   struct btrfs_block_rsv *block_rsv,
4412                                   u64 orig_bytes,
4413                                   enum btrfs_reserve_flush_enum flush)
4414 {
4415         struct btrfs_space_info *space_info = block_rsv->space_info;
4416         u64 used;
4417         u64 num_bytes = orig_bytes;
4418         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4419         int ret = 0;
4420         bool flushing = false;
4421
4422 again:
4423         ret = 0;
4424         spin_lock(&space_info->lock);
4425         /*
4426          * We only want to wait if somebody other than us is flushing and we
4427          * are actually allowed to flush all things.
4428          */
4429         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4430                space_info->flush) {
4431                 spin_unlock(&space_info->lock);
4432                 /*
4433                  * If we have a trans handle we can't wait because the flusher
4434                  * may have to commit the transaction, which would mean we would
4435                  * deadlock since we are waiting for the flusher to finish, but
4436                  * hold the current transaction open.
4437                  */
4438                 if (current->journal_info)
4439                         return -EAGAIN;
4440                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4441                 /* Must have been killed, return */
4442                 if (ret)
4443                         return -EINTR;
4444
4445                 spin_lock(&space_info->lock);
4446         }
4447
4448         ret = -ENOSPC;
4449         used = space_info->bytes_used + space_info->bytes_reserved +
4450                 space_info->bytes_pinned + space_info->bytes_readonly +
4451                 space_info->bytes_may_use;
4452
4453         /*
4454          * The idea here is that we've not already over-reserved the block group
4455          * then we can go ahead and save our reservation first and then start
4456          * flushing if we need to.  Otherwise if we've already overcommitted
4457          * lets start flushing stuff first and then come back and try to make
4458          * our reservation.
4459          */
4460         if (used <= space_info->total_bytes) {
4461                 if (used + orig_bytes <= space_info->total_bytes) {
4462                         space_info->bytes_may_use += orig_bytes;
4463                         trace_btrfs_space_reservation(root->fs_info,
4464                                 "space_info", space_info->flags, orig_bytes, 1);
4465                         ret = 0;
4466                 } else {
4467                         /*
4468                          * Ok set num_bytes to orig_bytes since we aren't
4469                          * overocmmitted, this way we only try and reclaim what
4470                          * we need.
4471                          */
4472                         num_bytes = orig_bytes;
4473                 }
4474         } else {
4475                 /*
4476                  * Ok we're over committed, set num_bytes to the overcommitted
4477                  * amount plus the amount of bytes that we need for this
4478                  * reservation.
4479                  */
4480                 num_bytes = used - space_info->total_bytes +
4481                         (orig_bytes * 2);
4482         }
4483
4484         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4485                 space_info->bytes_may_use += orig_bytes;
4486                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4487                                               space_info->flags, orig_bytes,
4488                                               1);
4489                 ret = 0;
4490         }
4491
4492         /*
4493          * Couldn't make our reservation, save our place so while we're trying
4494          * to reclaim space we can actually use it instead of somebody else
4495          * stealing it from us.
4496          *
4497          * We make the other tasks wait for the flush only when we can flush
4498          * all things.
4499          */
4500         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4501                 flushing = true;
4502                 space_info->flush = 1;
4503         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
4504                 used += orig_bytes;
4505                 if (need_do_async_reclaim(space_info, root->fs_info, used) &&
4506                     !work_busy(&root->fs_info->async_reclaim_work))
4507                         queue_work(system_unbound_wq,
4508                                    &root->fs_info->async_reclaim_work);
4509         }
4510         spin_unlock(&space_info->lock);
4511
4512         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4513                 goto out;
4514
4515         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4516                           flush_state);
4517         flush_state++;
4518
4519         /*
4520          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4521          * would happen. So skip delalloc flush.
4522          */
4523         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4524             (flush_state == FLUSH_DELALLOC ||
4525              flush_state == FLUSH_DELALLOC_WAIT))
4526                 flush_state = ALLOC_CHUNK;
4527
4528         if (!ret)
4529                 goto again;
4530         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4531                  flush_state < COMMIT_TRANS)
4532                 goto again;
4533         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4534                  flush_state <= COMMIT_TRANS)
4535                 goto again;
4536
4537 out:
4538         if (ret == -ENOSPC &&
4539             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4540                 struct btrfs_block_rsv *global_rsv =
4541                         &root->fs_info->global_block_rsv;
4542
4543                 if (block_rsv != global_rsv &&
4544                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4545                         ret = 0;
4546         }
4547         if (ret == -ENOSPC)
4548                 trace_btrfs_space_reservation(root->fs_info,
4549                                               "space_info:enospc",
4550                                               space_info->flags, orig_bytes, 1);
4551         if (flushing) {
4552                 spin_lock(&space_info->lock);
4553                 space_info->flush = 0;
4554                 wake_up_all(&space_info->wait);
4555                 spin_unlock(&space_info->lock);
4556         }
4557         return ret;
4558 }
4559
4560 static struct btrfs_block_rsv *get_block_rsv(
4561                                         const struct btrfs_trans_handle *trans,
4562                                         const struct btrfs_root *root)
4563 {
4564         struct btrfs_block_rsv *block_rsv = NULL;
4565
4566         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4567                 block_rsv = trans->block_rsv;
4568
4569         if (root == root->fs_info->csum_root && trans->adding_csums)
4570                 block_rsv = trans->block_rsv;
4571
4572         if (root == root->fs_info->uuid_root)
4573                 block_rsv = trans->block_rsv;
4574
4575         if (!block_rsv)
4576                 block_rsv = root->block_rsv;
4577
4578         if (!block_rsv)
4579                 block_rsv = &root->fs_info->empty_block_rsv;
4580
4581         return block_rsv;
4582 }
4583
4584 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4585                                u64 num_bytes)
4586 {
4587         int ret = -ENOSPC;
4588         spin_lock(&block_rsv->lock);
4589         if (block_rsv->reserved >= num_bytes) {
4590                 block_rsv->reserved -= num_bytes;
4591                 if (block_rsv->reserved < block_rsv->size)
4592                         block_rsv->full = 0;
4593                 ret = 0;
4594         }
4595         spin_unlock(&block_rsv->lock);
4596         return ret;
4597 }
4598
4599 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4600                                 u64 num_bytes, int update_size)
4601 {
4602         spin_lock(&block_rsv->lock);
4603         block_rsv->reserved += num_bytes;
4604         if (update_size)
4605                 block_rsv->size += num_bytes;
4606         else if (block_rsv->reserved >= block_rsv->size)
4607                 block_rsv->full = 1;
4608         spin_unlock(&block_rsv->lock);
4609 }
4610
4611 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4612                              struct btrfs_block_rsv *dest, u64 num_bytes,
4613                              int min_factor)
4614 {
4615         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4616         u64 min_bytes;
4617
4618         if (global_rsv->space_info != dest->space_info)
4619                 return -ENOSPC;
4620
4621         spin_lock(&global_rsv->lock);
4622         min_bytes = div_factor(global_rsv->size, min_factor);
4623         if (global_rsv->reserved < min_bytes + num_bytes) {
4624                 spin_unlock(&global_rsv->lock);
4625                 return -ENOSPC;
4626         }
4627         global_rsv->reserved -= num_bytes;
4628         if (global_rsv->reserved < global_rsv->size)
4629                 global_rsv->full = 0;
4630         spin_unlock(&global_rsv->lock);
4631
4632         block_rsv_add_bytes(dest, num_bytes, 1);
4633         return 0;
4634 }
4635
4636 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4637                                     struct btrfs_block_rsv *block_rsv,
4638                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4639 {
4640         struct btrfs_space_info *space_info = block_rsv->space_info;
4641
4642         spin_lock(&block_rsv->lock);
4643         if (num_bytes == (u64)-1)
4644                 num_bytes = block_rsv->size;
4645         block_rsv->size -= num_bytes;
4646         if (block_rsv->reserved >= block_rsv->size) {
4647                 num_bytes = block_rsv->reserved - block_rsv->size;
4648                 block_rsv->reserved = block_rsv->size;
4649                 block_rsv->full = 1;
4650         } else {
4651                 num_bytes = 0;
4652         }
4653         spin_unlock(&block_rsv->lock);
4654
4655         if (num_bytes > 0) {
4656                 if (dest) {
4657                         spin_lock(&dest->lock);
4658                         if (!dest->full) {
4659                                 u64 bytes_to_add;
4660
4661                                 bytes_to_add = dest->size - dest->reserved;
4662                                 bytes_to_add = min(num_bytes, bytes_to_add);
4663                                 dest->reserved += bytes_to_add;
4664                                 if (dest->reserved >= dest->size)
4665                                         dest->full = 1;
4666                                 num_bytes -= bytes_to_add;
4667                         }
4668                         spin_unlock(&dest->lock);
4669                 }
4670                 if (num_bytes) {
4671                         spin_lock(&space_info->lock);
4672                         space_info->bytes_may_use -= num_bytes;
4673                         trace_btrfs_space_reservation(fs_info, "space_info",
4674                                         space_info->flags, num_bytes, 0);
4675                         spin_unlock(&space_info->lock);
4676                 }
4677         }
4678 }
4679
4680 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4681                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4682 {
4683         int ret;
4684
4685         ret = block_rsv_use_bytes(src, num_bytes);
4686         if (ret)
4687                 return ret;
4688
4689         block_rsv_add_bytes(dst, num_bytes, 1);
4690         return 0;
4691 }
4692
4693 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4694 {
4695         memset(rsv, 0, sizeof(*rsv));
4696         spin_lock_init(&rsv->lock);
4697         rsv->type = type;
4698 }
4699
4700 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4701                                               unsigned short type)
4702 {
4703         struct btrfs_block_rsv *block_rsv;
4704         struct btrfs_fs_info *fs_info = root->fs_info;
4705
4706         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4707         if (!block_rsv)
4708                 return NULL;
4709
4710         btrfs_init_block_rsv(block_rsv, type);
4711         block_rsv->space_info = __find_space_info(fs_info,
4712                                                   BTRFS_BLOCK_GROUP_METADATA);
4713         return block_rsv;
4714 }
4715
4716 void btrfs_free_block_rsv(struct btrfs_root *root,
4717                           struct btrfs_block_rsv *rsv)
4718 {
4719         if (!rsv)
4720                 return;
4721         btrfs_block_rsv_release(root, rsv, (u64)-1);
4722         kfree(rsv);
4723 }
4724
4725 int btrfs_block_rsv_add(struct btrfs_root *root,
4726                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4727                         enum btrfs_reserve_flush_enum flush)
4728 {
4729         int ret;
4730
4731         if (num_bytes == 0)
4732                 return 0;
4733
4734         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4735         if (!ret) {
4736                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4737                 return 0;
4738         }
4739
4740         return ret;
4741 }
4742
4743 int btrfs_block_rsv_check(struct btrfs_root *root,
4744                           struct btrfs_block_rsv *block_rsv, int min_factor)
4745 {
4746         u64 num_bytes = 0;
4747         int ret = -ENOSPC;
4748
4749         if (!block_rsv)
4750                 return 0;
4751
4752         spin_lock(&block_rsv->lock);
4753         num_bytes = div_factor(block_rsv->size, min_factor);
4754         if (block_rsv->reserved >= num_bytes)
4755                 ret = 0;
4756         spin_unlock(&block_rsv->lock);
4757
4758         return ret;
4759 }
4760
4761 int btrfs_block_rsv_refill(struct btrfs_root *root,
4762                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4763                            enum btrfs_reserve_flush_enum flush)
4764 {
4765         u64 num_bytes = 0;
4766         int ret = -ENOSPC;
4767
4768         if (!block_rsv)
4769                 return 0;
4770
4771         spin_lock(&block_rsv->lock);
4772         num_bytes = min_reserved;
4773         if (block_rsv->reserved >= num_bytes)
4774                 ret = 0;
4775         else
4776                 num_bytes -= block_rsv->reserved;
4777         spin_unlock(&block_rsv->lock);
4778
4779         if (!ret)
4780                 return 0;
4781
4782         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4783         if (!ret) {
4784                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4785                 return 0;
4786         }
4787
4788         return ret;
4789 }
4790
4791 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4792                             struct btrfs_block_rsv *dst_rsv,
4793                             u64 num_bytes)
4794 {
4795         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4796 }
4797
4798 void btrfs_block_rsv_release(struct btrfs_root *root,
4799                              struct btrfs_block_rsv *block_rsv,
4800                              u64 num_bytes)
4801 {
4802         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4803         if (global_rsv == block_rsv ||
4804             block_rsv->space_info != global_rsv->space_info)
4805                 global_rsv = NULL;
4806         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4807                                 num_bytes);
4808 }
4809
4810 /*
4811  * helper to calculate size of global block reservation.
4812  * the desired value is sum of space used by extent tree,
4813  * checksum tree and root tree
4814  */
4815 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4816 {
4817         struct btrfs_space_info *sinfo;
4818         u64 num_bytes;
4819         u64 meta_used;
4820         u64 data_used;
4821         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4822
4823         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4824         spin_lock(&sinfo->lock);
4825         data_used = sinfo->bytes_used;
4826         spin_unlock(&sinfo->lock);
4827
4828         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4829         spin_lock(&sinfo->lock);
4830         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4831                 data_used = 0;
4832         meta_used = sinfo->bytes_used;
4833         spin_unlock(&sinfo->lock);
4834
4835         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4836                     csum_size * 2;
4837         num_bytes += div64_u64(data_used + meta_used, 50);
4838
4839         if (num_bytes * 3 > meta_used)
4840                 num_bytes = div64_u64(meta_used, 3);
4841
4842         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4843 }
4844
4845 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4846 {
4847         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4848         struct btrfs_space_info *sinfo = block_rsv->space_info;
4849         u64 num_bytes;
4850
4851         num_bytes = calc_global_metadata_size(fs_info);
4852
4853         spin_lock(&sinfo->lock);
4854         spin_lock(&block_rsv->lock);
4855
4856         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
4857
4858         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4859                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4860                     sinfo->bytes_may_use;
4861
4862         if (sinfo->total_bytes > num_bytes) {
4863                 num_bytes = sinfo->total_bytes - num_bytes;
4864                 block_rsv->reserved += num_bytes;
4865                 sinfo->bytes_may_use += num_bytes;
4866                 trace_btrfs_space_reservation(fs_info, "space_info",
4867                                       sinfo->flags, num_bytes, 1);
4868         }
4869
4870         if (block_rsv->reserved >= block_rsv->size) {
4871                 num_bytes = block_rsv->reserved - block_rsv->size;
4872                 sinfo->bytes_may_use -= num_bytes;
4873                 trace_btrfs_space_reservation(fs_info, "space_info",
4874                                       sinfo->flags, num_bytes, 0);
4875                 block_rsv->reserved = block_rsv->size;
4876                 block_rsv->full = 1;
4877         }
4878
4879         spin_unlock(&block_rsv->lock);
4880         spin_unlock(&sinfo->lock);
4881 }
4882
4883 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4884 {
4885         struct btrfs_space_info *space_info;
4886
4887         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4888         fs_info->chunk_block_rsv.space_info = space_info;
4889
4890         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4891         fs_info->global_block_rsv.space_info = space_info;
4892         fs_info->delalloc_block_rsv.space_info = space_info;
4893         fs_info->trans_block_rsv.space_info = space_info;
4894         fs_info->empty_block_rsv.space_info = space_info;
4895         fs_info->delayed_block_rsv.space_info = space_info;
4896
4897         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4898         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4899         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4900         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4901         if (fs_info->quota_root)
4902                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
4903         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4904
4905         update_global_block_rsv(fs_info);
4906 }
4907
4908 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4909 {
4910         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4911                                 (u64)-1);
4912         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4913         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4914         WARN_ON(fs_info->trans_block_rsv.size > 0);
4915         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4916         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4917         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4918         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4919         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4920 }
4921
4922 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4923                                   struct btrfs_root *root)
4924 {
4925         if (!trans->block_rsv)
4926                 return;
4927
4928         if (!trans->bytes_reserved)
4929                 return;
4930
4931         trace_btrfs_space_reservation(root->fs_info, "transaction",
4932                                       trans->transid, trans->bytes_reserved, 0);
4933         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4934         trans->bytes_reserved = 0;
4935 }
4936
4937 /* Can only return 0 or -ENOSPC */
4938 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4939                                   struct inode *inode)
4940 {
4941         struct btrfs_root *root = BTRFS_I(inode)->root;
4942         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4943         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4944
4945         /*
4946          * We need to hold space in order to delete our orphan item once we've
4947          * added it, so this takes the reservation so we can release it later
4948          * when we are truly done with the orphan item.
4949          */
4950         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4951         trace_btrfs_space_reservation(root->fs_info, "orphan",
4952                                       btrfs_ino(inode), num_bytes, 1);
4953         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4954 }
4955
4956 void btrfs_orphan_release_metadata(struct inode *inode)
4957 {
4958         struct btrfs_root *root = BTRFS_I(inode)->root;
4959         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4960         trace_btrfs_space_reservation(root->fs_info, "orphan",
4961                                       btrfs_ino(inode), num_bytes, 0);
4962         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4963 }
4964
4965 /*
4966  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4967  * root: the root of the parent directory
4968  * rsv: block reservation
4969  * items: the number of items that we need do reservation
4970  * qgroup_reserved: used to return the reserved size in qgroup
4971  *
4972  * This function is used to reserve the space for snapshot/subvolume
4973  * creation and deletion. Those operations are different with the
4974  * common file/directory operations, they change two fs/file trees
4975  * and root tree, the number of items that the qgroup reserves is
4976  * different with the free space reservation. So we can not use
4977  * the space reseravtion mechanism in start_transaction().
4978  */
4979 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4980                                      struct btrfs_block_rsv *rsv,
4981                                      int items,
4982                                      u64 *qgroup_reserved,
4983                                      bool use_global_rsv)
4984 {
4985         u64 num_bytes;
4986         int ret;
4987         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4988
4989         if (root->fs_info->quota_enabled) {
4990                 /* One for parent inode, two for dir entries */
4991                 num_bytes = 3 * root->leafsize;
4992                 ret = btrfs_qgroup_reserve(root, num_bytes);
4993                 if (ret)
4994                         return ret;
4995         } else {
4996                 num_bytes = 0;
4997         }
4998
4999         *qgroup_reserved = num_bytes;
5000
5001         num_bytes = btrfs_calc_trans_metadata_size(root, items);
5002         rsv->space_info = __find_space_info(root->fs_info,
5003                                             BTRFS_BLOCK_GROUP_METADATA);
5004         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5005                                   BTRFS_RESERVE_FLUSH_ALL);
5006
5007         if (ret == -ENOSPC && use_global_rsv)
5008                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
5009
5010         if (ret) {
5011                 if (*qgroup_reserved)
5012                         btrfs_qgroup_free(root, *qgroup_reserved);
5013         }
5014
5015         return ret;
5016 }
5017
5018 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5019                                       struct btrfs_block_rsv *rsv,
5020                                       u64 qgroup_reserved)
5021 {
5022         btrfs_block_rsv_release(root, rsv, (u64)-1);
5023         if (qgroup_reserved)
5024                 btrfs_qgroup_free(root, qgroup_reserved);
5025 }
5026
5027 /**
5028  * drop_outstanding_extent - drop an outstanding extent
5029  * @inode: the inode we're dropping the extent for
5030  *
5031  * This is called when we are freeing up an outstanding extent, either called
5032  * after an error or after an extent is written.  This will return the number of
5033  * reserved extents that need to be freed.  This must be called with
5034  * BTRFS_I(inode)->lock held.
5035  */
5036 static unsigned drop_outstanding_extent(struct inode *inode)
5037 {
5038         unsigned drop_inode_space = 0;
5039         unsigned dropped_extents = 0;
5040
5041         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
5042         BTRFS_I(inode)->outstanding_extents--;
5043
5044         if (BTRFS_I(inode)->outstanding_extents == 0 &&
5045             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5046                                &BTRFS_I(inode)->runtime_flags))
5047                 drop_inode_space = 1;
5048
5049         /*
5050          * If we have more or the same amount of outsanding extents than we have
5051          * reserved then we need to leave the reserved extents count alone.
5052          */
5053         if (BTRFS_I(inode)->outstanding_extents >=
5054             BTRFS_I(inode)->reserved_extents)
5055                 return drop_inode_space;
5056
5057         dropped_extents = BTRFS_I(inode)->reserved_extents -
5058                 BTRFS_I(inode)->outstanding_extents;
5059         BTRFS_I(inode)->reserved_extents -= dropped_extents;
5060         return dropped_extents + drop_inode_space;
5061 }
5062
5063 /**
5064  * calc_csum_metadata_size - return the amount of metada space that must be
5065  *      reserved/free'd for the given bytes.
5066  * @inode: the inode we're manipulating
5067  * @num_bytes: the number of bytes in question
5068  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5069  *
5070  * This adjusts the number of csum_bytes in the inode and then returns the
5071  * correct amount of metadata that must either be reserved or freed.  We
5072  * calculate how many checksums we can fit into one leaf and then divide the
5073  * number of bytes that will need to be checksumed by this value to figure out
5074  * how many checksums will be required.  If we are adding bytes then the number
5075  * may go up and we will return the number of additional bytes that must be
5076  * reserved.  If it is going down we will return the number of bytes that must
5077  * be freed.
5078  *
5079  * This must be called with BTRFS_I(inode)->lock held.
5080  */
5081 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5082                                    int reserve)
5083 {
5084         struct btrfs_root *root = BTRFS_I(inode)->root;
5085         u64 csum_size;
5086         int num_csums_per_leaf;
5087         int num_csums;
5088         int old_csums;
5089
5090         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5091             BTRFS_I(inode)->csum_bytes == 0)
5092                 return 0;
5093
5094         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
5095         if (reserve)
5096                 BTRFS_I(inode)->csum_bytes += num_bytes;
5097         else
5098                 BTRFS_I(inode)->csum_bytes -= num_bytes;
5099         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
5100         num_csums_per_leaf = (int)div64_u64(csum_size,
5101                                             sizeof(struct btrfs_csum_item) +
5102                                             sizeof(struct btrfs_disk_key));
5103         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
5104         num_csums = num_csums + num_csums_per_leaf - 1;
5105         num_csums = num_csums / num_csums_per_leaf;
5106
5107         old_csums = old_csums + num_csums_per_leaf - 1;
5108         old_csums = old_csums / num_csums_per_leaf;
5109
5110         /* No change, no need to reserve more */
5111         if (old_csums == num_csums)
5112                 return 0;
5113
5114         if (reserve)
5115                 return btrfs_calc_trans_metadata_size(root,
5116                                                       num_csums - old_csums);
5117
5118         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5119 }
5120
5121 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5122 {
5123         struct btrfs_root *root = BTRFS_I(inode)->root;
5124         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5125         u64 to_reserve = 0;
5126         u64 csum_bytes;
5127         unsigned nr_extents = 0;
5128         int extra_reserve = 0;
5129         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5130         int ret = 0;
5131         bool delalloc_lock = true;
5132         u64 to_free = 0;
5133         unsigned dropped;
5134
5135         /* If we are a free space inode we need to not flush since we will be in
5136          * the middle of a transaction commit.  We also don't need the delalloc
5137          * mutex since we won't race with anybody.  We need this mostly to make
5138          * lockdep shut its filthy mouth.
5139          */
5140         if (btrfs_is_free_space_inode(inode)) {
5141                 flush = BTRFS_RESERVE_NO_FLUSH;
5142                 delalloc_lock = false;
5143         }
5144
5145         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5146             btrfs_transaction_in_commit(root->fs_info))
5147                 schedule_timeout(1);
5148
5149         if (delalloc_lock)
5150                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5151
5152         num_bytes = ALIGN(num_bytes, root->sectorsize);
5153
5154         spin_lock(&BTRFS_I(inode)->lock);
5155         BTRFS_I(inode)->outstanding_extents++;
5156
5157         if (BTRFS_I(inode)->outstanding_extents >
5158             BTRFS_I(inode)->reserved_extents)
5159                 nr_extents = BTRFS_I(inode)->outstanding_extents -
5160                         BTRFS_I(inode)->reserved_extents;
5161
5162         /*
5163          * Add an item to reserve for updating the inode when we complete the
5164          * delalloc io.
5165          */
5166         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5167                       &BTRFS_I(inode)->runtime_flags)) {
5168                 nr_extents++;
5169                 extra_reserve = 1;
5170         }
5171
5172         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5173         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5174         csum_bytes = BTRFS_I(inode)->csum_bytes;
5175         spin_unlock(&BTRFS_I(inode)->lock);
5176
5177         if (root->fs_info->quota_enabled) {
5178                 ret = btrfs_qgroup_reserve(root, num_bytes +
5179                                            nr_extents * root->leafsize);
5180                 if (ret)
5181                         goto out_fail;
5182         }
5183
5184         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5185         if (unlikely(ret)) {
5186                 if (root->fs_info->quota_enabled)
5187                         btrfs_qgroup_free(root, num_bytes +
5188                                                 nr_extents * root->leafsize);
5189                 goto out_fail;
5190         }
5191
5192         spin_lock(&BTRFS_I(inode)->lock);
5193         if (extra_reserve) {
5194                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5195                         &BTRFS_I(inode)->runtime_flags);
5196                 nr_extents--;
5197         }
5198         BTRFS_I(inode)->reserved_extents += nr_extents;
5199         spin_unlock(&BTRFS_I(inode)->lock);
5200
5201         if (delalloc_lock)
5202                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5203
5204         if (to_reserve)
5205                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5206                                               btrfs_ino(inode), to_reserve, 1);
5207         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5208
5209         return 0;
5210
5211 out_fail:
5212         spin_lock(&BTRFS_I(inode)->lock);
5213         dropped = drop_outstanding_extent(inode);
5214         /*
5215          * If the inodes csum_bytes is the same as the original
5216          * csum_bytes then we know we haven't raced with any free()ers
5217          * so we can just reduce our inodes csum bytes and carry on.
5218          */
5219         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5220                 calc_csum_metadata_size(inode, num_bytes, 0);
5221         } else {
5222                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5223                 u64 bytes;
5224
5225                 /*
5226                  * This is tricky, but first we need to figure out how much we
5227                  * free'd from any free-ers that occured during this
5228                  * reservation, so we reset ->csum_bytes to the csum_bytes
5229                  * before we dropped our lock, and then call the free for the
5230                  * number of bytes that were freed while we were trying our
5231                  * reservation.
5232                  */
5233                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5234                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5235                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5236
5237
5238                 /*
5239                  * Now we need to see how much we would have freed had we not
5240                  * been making this reservation and our ->csum_bytes were not
5241                  * artificially inflated.
5242                  */
5243                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5244                 bytes = csum_bytes - orig_csum_bytes;
5245                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5246
5247                 /*
5248                  * Now reset ->csum_bytes to what it should be.  If bytes is
5249                  * more than to_free then we would have free'd more space had we
5250                  * not had an artificially high ->csum_bytes, so we need to free
5251                  * the remainder.  If bytes is the same or less then we don't
5252                  * need to do anything, the other free-ers did the correct
5253                  * thing.
5254                  */
5255                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5256                 if (bytes > to_free)
5257                         to_free = bytes - to_free;
5258                 else
5259                         to_free = 0;
5260         }
5261         spin_unlock(&BTRFS_I(inode)->lock);
5262         if (dropped)
5263                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5264
5265         if (to_free) {
5266                 btrfs_block_rsv_release(root, block_rsv, to_free);
5267                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5268                                               btrfs_ino(inode), to_free, 0);
5269         }
5270         if (delalloc_lock)
5271                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5272         return ret;
5273 }
5274
5275 /**
5276  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5277  * @inode: the inode to release the reservation for
5278  * @num_bytes: the number of bytes we're releasing
5279  *
5280  * This will release the metadata reservation for an inode.  This can be called
5281  * once we complete IO for a given set of bytes to release their metadata
5282  * reservations.
5283  */
5284 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5285 {
5286         struct btrfs_root *root = BTRFS_I(inode)->root;
5287         u64 to_free = 0;
5288         unsigned dropped;
5289
5290         num_bytes = ALIGN(num_bytes, root->sectorsize);
5291         spin_lock(&BTRFS_I(inode)->lock);
5292         dropped = drop_outstanding_extent(inode);
5293
5294         if (num_bytes)
5295                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5296         spin_unlock(&BTRFS_I(inode)->lock);
5297         if (dropped > 0)
5298                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5299
5300         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5301                                       btrfs_ino(inode), to_free, 0);
5302         if (root->fs_info->quota_enabled) {
5303                 btrfs_qgroup_free(root, num_bytes +
5304                                         dropped * root->leafsize);
5305         }
5306
5307         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5308                                 to_free);
5309 }
5310
5311 /**
5312  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5313  * @inode: inode we're writing to
5314  * @num_bytes: the number of bytes we want to allocate
5315  *
5316  * This will do the following things
5317  *
5318  * o reserve space in the data space info for num_bytes
5319  * o reserve space in the metadata space info based on number of outstanding
5320  *   extents and how much csums will be needed
5321  * o add to the inodes ->delalloc_bytes
5322  * o add it to the fs_info's delalloc inodes list.
5323  *
5324  * This will return 0 for success and -ENOSPC if there is no space left.
5325  */
5326 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5327 {
5328         int ret;
5329
5330         ret = btrfs_check_data_free_space(inode, num_bytes);
5331         if (ret)
5332                 return ret;
5333
5334         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5335         if (ret) {
5336                 btrfs_free_reserved_data_space(inode, num_bytes);
5337                 return ret;
5338         }
5339
5340         return 0;
5341 }
5342
5343 /**
5344  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5345  * @inode: inode we're releasing space for
5346  * @num_bytes: the number of bytes we want to free up
5347  *
5348  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5349  * called in the case that we don't need the metadata AND data reservations
5350  * anymore.  So if there is an error or we insert an inline extent.
5351  *
5352  * This function will release the metadata space that was not used and will
5353  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5354  * list if there are no delalloc bytes left.
5355  */
5356 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5357 {
5358         btrfs_delalloc_release_metadata(inode, num_bytes);
5359         btrfs_free_reserved_data_space(inode, num_bytes);
5360 }
5361
5362 static int update_block_group(struct btrfs_root *root,
5363                               u64 bytenr, u64 num_bytes, int alloc)
5364 {
5365         struct btrfs_block_group_cache *cache = NULL;
5366         struct btrfs_fs_info *info = root->fs_info;
5367         u64 total = num_bytes;
5368         u64 old_val;
5369         u64 byte_in_group;
5370         int factor;
5371
5372         /* block accounting for super block */
5373         spin_lock(&info->delalloc_root_lock);
5374         old_val = btrfs_super_bytes_used(info->super_copy);
5375         if (alloc)
5376                 old_val += num_bytes;
5377         else
5378                 old_val -= num_bytes;
5379         btrfs_set_super_bytes_used(info->super_copy, old_val);
5380         spin_unlock(&info->delalloc_root_lock);
5381
5382         while (total) {
5383                 cache = btrfs_lookup_block_group(info, bytenr);
5384                 if (!cache)
5385                         return -ENOENT;
5386                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5387                                     BTRFS_BLOCK_GROUP_RAID1 |
5388                                     BTRFS_BLOCK_GROUP_RAID10))
5389                         factor = 2;
5390                 else
5391                         factor = 1;
5392                 /*
5393                  * If this block group has free space cache written out, we
5394                  * need to make sure to load it if we are removing space.  This
5395                  * is because we need the unpinning stage to actually add the
5396                  * space back to the block group, otherwise we will leak space.
5397                  */
5398                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5399                         cache_block_group(cache, 1);
5400
5401                 byte_in_group = bytenr - cache->key.objectid;
5402                 WARN_ON(byte_in_group > cache->key.offset);
5403
5404                 spin_lock(&cache->space_info->lock);
5405                 spin_lock(&cache->lock);
5406
5407                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5408                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5409                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5410
5411                 cache->dirty = 1;
5412                 old_val = btrfs_block_group_used(&cache->item);
5413                 num_bytes = min(total, cache->key.offset - byte_in_group);
5414                 if (alloc) {
5415                         old_val += num_bytes;
5416                         btrfs_set_block_group_used(&cache->item, old_val);
5417                         cache->reserved -= num_bytes;
5418                         cache->space_info->bytes_reserved -= num_bytes;
5419                         cache->space_info->bytes_used += num_bytes;
5420                         cache->space_info->disk_used += num_bytes * factor;
5421                         spin_unlock(&cache->lock);
5422                         spin_unlock(&cache->space_info->lock);
5423                 } else {
5424                         old_val -= num_bytes;
5425                         btrfs_set_block_group_used(&cache->item, old_val);
5426                         cache->pinned += num_bytes;
5427                         cache->space_info->bytes_pinned += num_bytes;
5428                         cache->space_info->bytes_used -= num_bytes;
5429                         cache->space_info->disk_used -= num_bytes * factor;
5430                         spin_unlock(&cache->lock);
5431                         spin_unlock(&cache->space_info->lock);
5432
5433                         set_extent_dirty(info->pinned_extents,
5434                                          bytenr, bytenr + num_bytes - 1,
5435                                          GFP_NOFS | __GFP_NOFAIL);
5436                 }
5437                 btrfs_put_block_group(cache);
5438                 total -= num_bytes;
5439                 bytenr += num_bytes;
5440         }
5441         return 0;
5442 }
5443
5444 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5445 {
5446         struct btrfs_block_group_cache *cache;
5447         u64 bytenr;
5448
5449         spin_lock(&root->fs_info->block_group_cache_lock);
5450         bytenr = root->fs_info->first_logical_byte;
5451         spin_unlock(&root->fs_info->block_group_cache_lock);
5452
5453         if (bytenr < (u64)-1)
5454                 return bytenr;
5455
5456         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5457         if (!cache)
5458                 return 0;
5459
5460         bytenr = cache->key.objectid;
5461         btrfs_put_block_group(cache);
5462
5463         return bytenr;
5464 }
5465
5466 static int pin_down_extent(struct btrfs_root *root,
5467                            struct btrfs_block_group_cache *cache,
5468                            u64 bytenr, u64 num_bytes, int reserved)
5469 {
5470         spin_lock(&cache->space_info->lock);
5471         spin_lock(&cache->lock);
5472         cache->pinned += num_bytes;
5473         cache->space_info->bytes_pinned += num_bytes;
5474         if (reserved) {
5475                 cache->reserved -= num_bytes;
5476                 cache->space_info->bytes_reserved -= num_bytes;
5477         }
5478         spin_unlock(&cache->lock);
5479         spin_unlock(&cache->space_info->lock);
5480
5481         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5482                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5483         if (reserved)
5484                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
5485         return 0;
5486 }
5487
5488 /*
5489  * this function must be called within transaction
5490  */
5491 int btrfs_pin_extent(struct btrfs_root *root,
5492                      u64 bytenr, u64 num_bytes, int reserved)
5493 {
5494         struct btrfs_block_group_cache *cache;
5495
5496         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5497         BUG_ON(!cache); /* Logic error */
5498
5499         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5500
5501         btrfs_put_block_group(cache);
5502         return 0;
5503 }
5504
5505 /*
5506  * this function must be called within transaction
5507  */
5508 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5509                                     u64 bytenr, u64 num_bytes)
5510 {
5511         struct btrfs_block_group_cache *cache;
5512         int ret;
5513
5514         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5515         if (!cache)
5516                 return -EINVAL;
5517
5518         /*
5519          * pull in the free space cache (if any) so that our pin
5520          * removes the free space from the cache.  We have load_only set
5521          * to one because the slow code to read in the free extents does check
5522          * the pinned extents.
5523          */
5524         cache_block_group(cache, 1);
5525
5526         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5527
5528         /* remove us from the free space cache (if we're there at all) */
5529         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5530         btrfs_put_block_group(cache);
5531         return ret;
5532 }
5533
5534 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5535 {
5536         int ret;
5537         struct btrfs_block_group_cache *block_group;
5538         struct btrfs_caching_control *caching_ctl;
5539
5540         block_group = btrfs_lookup_block_group(root->fs_info, start);
5541         if (!block_group)
5542                 return -EINVAL;
5543
5544         cache_block_group(block_group, 0);
5545         caching_ctl = get_caching_control(block_group);
5546
5547         if (!caching_ctl) {
5548                 /* Logic error */
5549                 BUG_ON(!block_group_cache_done(block_group));
5550                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5551         } else {
5552                 mutex_lock(&caching_ctl->mutex);
5553
5554                 if (start >= caching_ctl->progress) {
5555                         ret = add_excluded_extent(root, start, num_bytes);
5556                 } else if (start + num_bytes <= caching_ctl->progress) {
5557                         ret = btrfs_remove_free_space(block_group,
5558                                                       start, num_bytes);
5559                 } else {
5560                         num_bytes = caching_ctl->progress - start;
5561                         ret = btrfs_remove_free_space(block_group,
5562                                                       start, num_bytes);
5563                         if (ret)
5564                                 goto out_lock;
5565
5566                         num_bytes = (start + num_bytes) -
5567                                 caching_ctl->progress;
5568                         start = caching_ctl->progress;
5569                         ret = add_excluded_extent(root, start, num_bytes);
5570                 }
5571 out_lock:
5572                 mutex_unlock(&caching_ctl->mutex);
5573                 put_caching_control(caching_ctl);
5574         }
5575         btrfs_put_block_group(block_group);
5576         return ret;
5577 }
5578
5579 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5580                                  struct extent_buffer *eb)
5581 {
5582         struct btrfs_file_extent_item *item;
5583         struct btrfs_key key;
5584         int found_type;
5585         int i;
5586
5587         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5588                 return 0;
5589
5590         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5591                 btrfs_item_key_to_cpu(eb, &key, i);
5592                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5593                         continue;
5594                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5595                 found_type = btrfs_file_extent_type(eb, item);
5596                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5597                         continue;
5598                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5599                         continue;
5600                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5601                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5602                 __exclude_logged_extent(log, key.objectid, key.offset);
5603         }
5604
5605         return 0;
5606 }
5607
5608 /**
5609  * btrfs_update_reserved_bytes - update the block_group and space info counters
5610  * @cache:      The cache we are manipulating
5611  * @num_bytes:  The number of bytes in question
5612  * @reserve:    One of the reservation enums
5613  * @delalloc:   The blocks are allocated for the delalloc write
5614  *
5615  * This is called by the allocator when it reserves space, or by somebody who is
5616  * freeing space that was never actually used on disk.  For example if you
5617  * reserve some space for a new leaf in transaction A and before transaction A
5618  * commits you free that leaf, you call this with reserve set to 0 in order to
5619  * clear the reservation.
5620  *
5621  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5622  * ENOSPC accounting.  For data we handle the reservation through clearing the
5623  * delalloc bits in the io_tree.  We have to do this since we could end up
5624  * allocating less disk space for the amount of data we have reserved in the
5625  * case of compression.
5626  *
5627  * If this is a reservation and the block group has become read only we cannot
5628  * make the reservation and return -EAGAIN, otherwise this function always
5629  * succeeds.
5630  */
5631 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5632                                        u64 num_bytes, int reserve, int delalloc)
5633 {
5634         struct btrfs_space_info *space_info = cache->space_info;
5635         int ret = 0;
5636
5637         spin_lock(&space_info->lock);
5638         spin_lock(&cache->lock);
5639         if (reserve != RESERVE_FREE) {
5640                 if (cache->ro) {
5641                         ret = -EAGAIN;
5642                 } else {
5643                         cache->reserved += num_bytes;
5644                         space_info->bytes_reserved += num_bytes;
5645                         if (reserve == RESERVE_ALLOC) {
5646                                 trace_btrfs_space_reservation(cache->fs_info,
5647                                                 "space_info", space_info->flags,
5648                                                 num_bytes, 0);
5649                                 space_info->bytes_may_use -= num_bytes;
5650                         }
5651
5652                         if (delalloc)
5653                                 cache->delalloc_bytes += num_bytes;
5654                 }
5655         } else {
5656                 if (cache->ro)
5657                         space_info->bytes_readonly += num_bytes;
5658                 cache->reserved -= num_bytes;
5659                 space_info->bytes_reserved -= num_bytes;
5660
5661                 if (delalloc)
5662                         cache->delalloc_bytes -= num_bytes;
5663         }
5664         spin_unlock(&cache->lock);
5665         spin_unlock(&space_info->lock);
5666         return ret;
5667 }
5668
5669 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5670                                 struct btrfs_root *root)
5671 {
5672         struct btrfs_fs_info *fs_info = root->fs_info;
5673         struct btrfs_caching_control *next;
5674         struct btrfs_caching_control *caching_ctl;
5675         struct btrfs_block_group_cache *cache;
5676
5677         down_write(&fs_info->commit_root_sem);
5678
5679         list_for_each_entry_safe(caching_ctl, next,
5680                                  &fs_info->caching_block_groups, list) {
5681                 cache = caching_ctl->block_group;
5682                 if (block_group_cache_done(cache)) {
5683                         cache->last_byte_to_unpin = (u64)-1;
5684                         list_del_init(&caching_ctl->list);
5685                         put_caching_control(caching_ctl);
5686                 } else {
5687                         cache->last_byte_to_unpin = caching_ctl->progress;
5688                 }
5689         }
5690
5691         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5692                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5693         else
5694                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5695
5696         up_write(&fs_info->commit_root_sem);
5697
5698         update_global_block_rsv(fs_info);
5699 }
5700
5701 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
5702 {
5703         struct btrfs_fs_info *fs_info = root->fs_info;
5704         struct btrfs_block_group_cache *cache = NULL;
5705         struct btrfs_space_info *space_info;
5706         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5707         u64 len;
5708         bool readonly;
5709
5710         while (start <= end) {
5711                 readonly = false;
5712                 if (!cache ||
5713                     start >= cache->key.objectid + cache->key.offset) {
5714                         if (cache)
5715                                 btrfs_put_block_group(cache);
5716                         cache = btrfs_lookup_block_group(fs_info, start);
5717                         BUG_ON(!cache); /* Logic error */
5718                 }
5719
5720                 len = cache->key.objectid + cache->key.offset - start;
5721                 len = min(len, end + 1 - start);
5722
5723                 if (start < cache->last_byte_to_unpin) {
5724                         len = min(len, cache->last_byte_to_unpin - start);
5725                         btrfs_add_free_space(cache, start, len);
5726                 }
5727
5728                 start += len;
5729                 space_info = cache->space_info;
5730
5731                 spin_lock(&space_info->lock);
5732                 spin_lock(&cache->lock);
5733                 cache->pinned -= len;
5734                 space_info->bytes_pinned -= len;
5735                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
5736                 if (cache->ro) {
5737                         space_info->bytes_readonly += len;
5738                         readonly = true;
5739                 }
5740                 spin_unlock(&cache->lock);
5741                 if (!readonly && global_rsv->space_info == space_info) {
5742                         spin_lock(&global_rsv->lock);
5743                         if (!global_rsv->full) {
5744                                 len = min(len, global_rsv->size -
5745                                           global_rsv->reserved);
5746                                 global_rsv->reserved += len;
5747                                 space_info->bytes_may_use += len;
5748                                 if (global_rsv->reserved >= global_rsv->size)
5749                                         global_rsv->full = 1;
5750                         }
5751                         spin_unlock(&global_rsv->lock);
5752                 }
5753                 spin_unlock(&space_info->lock);
5754         }
5755
5756         if (cache)
5757                 btrfs_put_block_group(cache);
5758         return 0;
5759 }
5760
5761 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5762                                struct btrfs_root *root)
5763 {
5764         struct btrfs_fs_info *fs_info = root->fs_info;
5765         struct extent_io_tree *unpin;
5766         u64 start;
5767         u64 end;
5768         int ret;
5769
5770         if (trans->aborted)
5771                 return 0;
5772
5773         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5774                 unpin = &fs_info->freed_extents[1];
5775         else
5776                 unpin = &fs_info->freed_extents[0];
5777
5778         while (1) {
5779                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5780                                             EXTENT_DIRTY, NULL);
5781                 if (ret)
5782                         break;
5783
5784                 if (btrfs_test_opt(root, DISCARD))
5785                         ret = btrfs_discard_extent(root, start,
5786                                                    end + 1 - start, NULL);
5787
5788                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5789                 unpin_extent_range(root, start, end);
5790                 cond_resched();
5791         }
5792
5793         return 0;
5794 }
5795
5796 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
5797                              u64 owner, u64 root_objectid)
5798 {
5799         struct btrfs_space_info *space_info;
5800         u64 flags;
5801
5802         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5803                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
5804                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
5805                 else
5806                         flags = BTRFS_BLOCK_GROUP_METADATA;
5807         } else {
5808                 flags = BTRFS_BLOCK_GROUP_DATA;
5809         }
5810
5811         space_info = __find_space_info(fs_info, flags);
5812         BUG_ON(!space_info); /* Logic bug */
5813         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
5814 }
5815
5816
5817 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5818                                 struct btrfs_root *root,
5819                                 u64 bytenr, u64 num_bytes, u64 parent,
5820                                 u64 root_objectid, u64 owner_objectid,
5821                                 u64 owner_offset, int refs_to_drop,
5822                                 struct btrfs_delayed_extent_op *extent_op,
5823                                 int no_quota)
5824 {
5825         struct btrfs_key key;
5826         struct btrfs_path *path;
5827         struct btrfs_fs_info *info = root->fs_info;
5828         struct btrfs_root *extent_root = info->extent_root;
5829         struct extent_buffer *leaf;
5830         struct btrfs_extent_item *ei;
5831         struct btrfs_extent_inline_ref *iref;
5832         int ret;
5833         int is_data;
5834         int extent_slot = 0;
5835         int found_extent = 0;
5836         int num_to_del = 1;
5837         u32 item_size;
5838         u64 refs;
5839         int last_ref = 0;
5840         enum btrfs_qgroup_operation_type type = BTRFS_QGROUP_OPER_SUB_EXCL;
5841         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
5842                                                  SKINNY_METADATA);
5843
5844         if (!info->quota_enabled || !is_fstree(root_objectid))
5845                 no_quota = 1;
5846
5847         path = btrfs_alloc_path();
5848         if (!path)
5849                 return -ENOMEM;
5850
5851         path->reada = 1;
5852         path->leave_spinning = 1;
5853
5854         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5855         BUG_ON(!is_data && refs_to_drop != 1);
5856
5857         if (is_data)
5858                 skinny_metadata = 0;
5859
5860         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5861                                     bytenr, num_bytes, parent,
5862                                     root_objectid, owner_objectid,
5863                                     owner_offset);
5864         if (ret == 0) {
5865                 extent_slot = path->slots[0];
5866                 while (extent_slot >= 0) {
5867                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5868                                               extent_slot);
5869                         if (key.objectid != bytenr)
5870                                 break;
5871                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5872                             key.offset == num_bytes) {
5873                                 found_extent = 1;
5874                                 break;
5875                         }
5876                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
5877                             key.offset == owner_objectid) {
5878                                 found_extent = 1;
5879                                 break;
5880                         }
5881                         if (path->slots[0] - extent_slot > 5)
5882                                 break;
5883                         extent_slot--;
5884                 }
5885 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5886                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5887                 if (found_extent && item_size < sizeof(*ei))
5888                         found_extent = 0;
5889 #endif
5890                 if (!found_extent) {
5891                         BUG_ON(iref);
5892                         ret = remove_extent_backref(trans, extent_root, path,
5893                                                     NULL, refs_to_drop,
5894                                                     is_data, &last_ref);
5895                         if (ret) {
5896                                 btrfs_abort_transaction(trans, extent_root, ret);
5897                                 goto out;
5898                         }
5899                         btrfs_release_path(path);
5900                         path->leave_spinning = 1;
5901
5902                         key.objectid = bytenr;
5903                         key.type = BTRFS_EXTENT_ITEM_KEY;
5904                         key.offset = num_bytes;
5905
5906                         if (!is_data && skinny_metadata) {
5907                                 key.type = BTRFS_METADATA_ITEM_KEY;
5908                                 key.offset = owner_objectid;
5909                         }
5910
5911                         ret = btrfs_search_slot(trans, extent_root,
5912                                                 &key, path, -1, 1);
5913                         if (ret > 0 && skinny_metadata && path->slots[0]) {
5914                                 /*
5915                                  * Couldn't find our skinny metadata item,
5916                                  * see if we have ye olde extent item.
5917                                  */
5918                                 path->slots[0]--;
5919                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
5920                                                       path->slots[0]);
5921                                 if (key.objectid == bytenr &&
5922                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
5923                                     key.offset == num_bytes)
5924                                         ret = 0;
5925                         }
5926
5927                         if (ret > 0 && skinny_metadata) {
5928                                 skinny_metadata = false;
5929                                 key.objectid = bytenr;
5930                                 key.type = BTRFS_EXTENT_ITEM_KEY;
5931                                 key.offset = num_bytes;
5932                                 btrfs_release_path(path);
5933                                 ret = btrfs_search_slot(trans, extent_root,
5934                                                         &key, path, -1, 1);
5935                         }
5936
5937                         if (ret) {
5938                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5939                                         ret, bytenr);
5940                                 if (ret > 0)
5941                                         btrfs_print_leaf(extent_root,
5942                                                          path->nodes[0]);
5943                         }
5944                         if (ret < 0) {
5945                                 btrfs_abort_transaction(trans, extent_root, ret);
5946                                 goto out;
5947                         }
5948                         extent_slot = path->slots[0];
5949                 }
5950         } else if (WARN_ON(ret == -ENOENT)) {
5951                 btrfs_print_leaf(extent_root, path->nodes[0]);
5952                 btrfs_err(info,
5953                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
5954                         bytenr, parent, root_objectid, owner_objectid,
5955                         owner_offset);
5956                 btrfs_abort_transaction(trans, extent_root, ret);
5957                 goto out;
5958         } else {
5959                 btrfs_abort_transaction(trans, extent_root, ret);
5960                 goto out;
5961         }
5962
5963         leaf = path->nodes[0];
5964         item_size = btrfs_item_size_nr(leaf, extent_slot);
5965 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5966         if (item_size < sizeof(*ei)) {
5967                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5968                 ret = convert_extent_item_v0(trans, extent_root, path,
5969                                              owner_objectid, 0);
5970                 if (ret < 0) {
5971                         btrfs_abort_transaction(trans, extent_root, ret);
5972                         goto out;
5973                 }
5974
5975                 btrfs_release_path(path);
5976                 path->leave_spinning = 1;
5977
5978                 key.objectid = bytenr;
5979                 key.type = BTRFS_EXTENT_ITEM_KEY;
5980                 key.offset = num_bytes;
5981
5982                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5983                                         -1, 1);
5984                 if (ret) {
5985                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5986                                 ret, bytenr);
5987                         btrfs_print_leaf(extent_root, path->nodes[0]);
5988                 }
5989                 if (ret < 0) {
5990                         btrfs_abort_transaction(trans, extent_root, ret);
5991                         goto out;
5992                 }
5993
5994                 extent_slot = path->slots[0];
5995                 leaf = path->nodes[0];
5996                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5997         }
5998 #endif
5999         BUG_ON(item_size < sizeof(*ei));
6000         ei = btrfs_item_ptr(leaf, extent_slot,
6001                             struct btrfs_extent_item);
6002         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6003             key.type == BTRFS_EXTENT_ITEM_KEY) {
6004                 struct btrfs_tree_block_info *bi;
6005                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6006                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6007                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6008         }
6009
6010         refs = btrfs_extent_refs(leaf, ei);
6011         if (refs < refs_to_drop) {
6012                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
6013                           "for bytenr %Lu", refs_to_drop, refs, bytenr);
6014                 ret = -EINVAL;
6015                 btrfs_abort_transaction(trans, extent_root, ret);
6016                 goto out;
6017         }
6018         refs -= refs_to_drop;
6019
6020         if (refs > 0) {
6021                 type = BTRFS_QGROUP_OPER_SUB_SHARED;
6022                 if (extent_op)
6023                         __run_delayed_extent_op(extent_op, leaf, ei);
6024                 /*
6025                  * In the case of inline back ref, reference count will
6026                  * be updated by remove_extent_backref
6027                  */
6028                 if (iref) {
6029                         BUG_ON(!found_extent);
6030                 } else {
6031                         btrfs_set_extent_refs(leaf, ei, refs);
6032                         btrfs_mark_buffer_dirty(leaf);
6033                 }
6034                 if (found_extent) {
6035                         ret = remove_extent_backref(trans, extent_root, path,
6036                                                     iref, refs_to_drop,
6037                                                     is_data, &last_ref);
6038                         if (ret) {
6039                                 btrfs_abort_transaction(trans, extent_root, ret);
6040                                 goto out;
6041                         }
6042                 }
6043                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
6044                                  root_objectid);
6045         } else {
6046                 if (found_extent) {
6047                         BUG_ON(is_data && refs_to_drop !=
6048                                extent_data_ref_count(root, path, iref));
6049                         if (iref) {
6050                                 BUG_ON(path->slots[0] != extent_slot);
6051                         } else {
6052                                 BUG_ON(path->slots[0] != extent_slot + 1);
6053                                 path->slots[0] = extent_slot;
6054                                 num_to_del = 2;
6055                         }
6056                 }
6057
6058                 last_ref = 1;
6059                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6060                                       num_to_del);
6061                 if (ret) {
6062                         btrfs_abort_transaction(trans, extent_root, ret);
6063                         goto out;
6064                 }
6065                 btrfs_release_path(path);
6066
6067                 if (is_data) {
6068                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
6069                         if (ret) {
6070                                 btrfs_abort_transaction(trans, extent_root, ret);
6071                                 goto out;
6072                         }
6073                 }
6074
6075                 ret = update_block_group(root, bytenr, num_bytes, 0);
6076                 if (ret) {
6077                         btrfs_abort_transaction(trans, extent_root, ret);
6078                         goto out;
6079                 }
6080         }
6081         btrfs_release_path(path);
6082
6083         /* Deal with the quota accounting */
6084         if (!ret && last_ref && !no_quota) {
6085                 int mod_seq = 0;
6086
6087                 if (owner_objectid >= BTRFS_FIRST_FREE_OBJECTID &&
6088                     type == BTRFS_QGROUP_OPER_SUB_SHARED)
6089                         mod_seq = 1;
6090
6091                 ret = btrfs_qgroup_record_ref(trans, info, root_objectid,
6092                                               bytenr, num_bytes, type,
6093                                               mod_seq);
6094         }
6095 out:
6096         btrfs_free_path(path);
6097         return ret;
6098 }
6099
6100 /*
6101  * when we free an block, it is possible (and likely) that we free the last
6102  * delayed ref for that extent as well.  This searches the delayed ref tree for
6103  * a given extent, and if there are no other delayed refs to be processed, it
6104  * removes it from the tree.
6105  */
6106 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6107                                       struct btrfs_root *root, u64 bytenr)
6108 {
6109         struct btrfs_delayed_ref_head *head;
6110         struct btrfs_delayed_ref_root *delayed_refs;
6111         int ret = 0;
6112
6113         delayed_refs = &trans->transaction->delayed_refs;
6114         spin_lock(&delayed_refs->lock);
6115         head = btrfs_find_delayed_ref_head(trans, bytenr);
6116         if (!head)
6117                 goto out_delayed_unlock;
6118
6119         spin_lock(&head->lock);
6120         if (rb_first(&head->ref_root))
6121                 goto out;
6122
6123         if (head->extent_op) {
6124                 if (!head->must_insert_reserved)
6125                         goto out;
6126                 btrfs_free_delayed_extent_op(head->extent_op);
6127                 head->extent_op = NULL;
6128         }
6129
6130         /*
6131          * waiting for the lock here would deadlock.  If someone else has it
6132          * locked they are already in the process of dropping it anyway
6133          */
6134         if (!mutex_trylock(&head->mutex))
6135                 goto out;
6136
6137         /*
6138          * at this point we have a head with no other entries.  Go
6139          * ahead and process it.
6140          */
6141         head->node.in_tree = 0;
6142         rb_erase(&head->href_node, &delayed_refs->href_root);
6143
6144         atomic_dec(&delayed_refs->num_entries);
6145
6146         /*
6147          * we don't take a ref on the node because we're removing it from the
6148          * tree, so we just steal the ref the tree was holding.
6149          */
6150         delayed_refs->num_heads--;
6151         if (head->processing == 0)
6152                 delayed_refs->num_heads_ready--;
6153         head->processing = 0;
6154         spin_unlock(&head->lock);
6155         spin_unlock(&delayed_refs->lock);
6156
6157         BUG_ON(head->extent_op);
6158         if (head->must_insert_reserved)
6159                 ret = 1;
6160
6161         mutex_unlock(&head->mutex);
6162         btrfs_put_delayed_ref(&head->node);
6163         return ret;
6164 out:
6165         spin_unlock(&head->lock);
6166
6167 out_delayed_unlock:
6168         spin_unlock(&delayed_refs->lock);
6169         return 0;
6170 }
6171
6172 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6173                            struct btrfs_root *root,
6174                            struct extent_buffer *buf,
6175                            u64 parent, int last_ref)
6176 {
6177         struct btrfs_block_group_cache *cache = NULL;
6178         int pin = 1;
6179         int ret;
6180
6181         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6182                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6183                                         buf->start, buf->len,
6184                                         parent, root->root_key.objectid,
6185                                         btrfs_header_level(buf),
6186                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
6187                 BUG_ON(ret); /* -ENOMEM */
6188         }
6189
6190         if (!last_ref)
6191                 return;
6192
6193         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6194
6195         if (btrfs_header_generation(buf) == trans->transid) {
6196                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6197                         ret = check_ref_cleanup(trans, root, buf->start);
6198                         if (!ret)
6199                                 goto out;
6200                 }
6201
6202                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6203                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6204                         goto out;
6205                 }
6206
6207                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6208
6209                 btrfs_add_free_space(cache, buf->start, buf->len);
6210                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
6211                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6212                 pin = 0;
6213         }
6214 out:
6215         if (pin)
6216                 add_pinned_bytes(root->fs_info, buf->len,
6217                                  btrfs_header_level(buf),
6218                                  root->root_key.objectid);
6219
6220         /*
6221          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6222          * anymore.
6223          */
6224         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6225         btrfs_put_block_group(cache);
6226 }
6227
6228 /* Can return -ENOMEM */
6229 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6230                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6231                       u64 owner, u64 offset, int no_quota)
6232 {
6233         int ret;
6234         struct btrfs_fs_info *fs_info = root->fs_info;
6235
6236 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
6237         if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state)))
6238                 return 0;
6239 #endif
6240         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6241
6242         /*
6243          * tree log blocks never actually go into the extent allocation
6244          * tree, just update pinning info and exit early.
6245          */
6246         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6247                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6248                 /* unlocks the pinned mutex */
6249                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6250                 ret = 0;
6251         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6252                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6253                                         num_bytes,
6254                                         parent, root_objectid, (int)owner,
6255                                         BTRFS_DROP_DELAYED_REF, NULL, no_quota);
6256         } else {
6257                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6258                                                 num_bytes,
6259                                                 parent, root_objectid, owner,
6260                                                 offset, BTRFS_DROP_DELAYED_REF,
6261                                                 NULL, no_quota);
6262         }
6263         return ret;
6264 }
6265
6266 static u64 stripe_align(struct btrfs_root *root,
6267                         struct btrfs_block_group_cache *cache,
6268                         u64 val, u64 num_bytes)
6269 {
6270         u64 ret = ALIGN(val, root->stripesize);
6271         return ret;
6272 }
6273
6274 /*
6275  * when we wait for progress in the block group caching, its because
6276  * our allocation attempt failed at least once.  So, we must sleep
6277  * and let some progress happen before we try again.
6278  *
6279  * This function will sleep at least once waiting for new free space to
6280  * show up, and then it will check the block group free space numbers
6281  * for our min num_bytes.  Another option is to have it go ahead
6282  * and look in the rbtree for a free extent of a given size, but this
6283  * is a good start.
6284  *
6285  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6286  * any of the information in this block group.
6287  */
6288 static noinline void
6289 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6290                                 u64 num_bytes)
6291 {
6292         struct btrfs_caching_control *caching_ctl;
6293
6294         caching_ctl = get_caching_control(cache);
6295         if (!caching_ctl)
6296                 return;
6297
6298         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6299                    (cache->free_space_ctl->free_space >= num_bytes));
6300
6301         put_caching_control(caching_ctl);
6302 }
6303
6304 static noinline int
6305 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6306 {
6307         struct btrfs_caching_control *caching_ctl;
6308         int ret = 0;
6309
6310         caching_ctl = get_caching_control(cache);
6311         if (!caching_ctl)
6312                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6313
6314         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6315         if (cache->cached == BTRFS_CACHE_ERROR)
6316                 ret = -EIO;
6317         put_caching_control(caching_ctl);
6318         return ret;
6319 }
6320
6321 int __get_raid_index(u64 flags)
6322 {
6323         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6324                 return BTRFS_RAID_RAID10;
6325         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6326                 return BTRFS_RAID_RAID1;
6327         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6328                 return BTRFS_RAID_DUP;
6329         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6330                 return BTRFS_RAID_RAID0;
6331         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6332                 return BTRFS_RAID_RAID5;
6333         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6334                 return BTRFS_RAID_RAID6;
6335
6336         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6337 }
6338
6339 int get_block_group_index(struct btrfs_block_group_cache *cache)
6340 {
6341         return __get_raid_index(cache->flags);
6342 }
6343
6344 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
6345         [BTRFS_RAID_RAID10]     = "raid10",
6346         [BTRFS_RAID_RAID1]      = "raid1",
6347         [BTRFS_RAID_DUP]        = "dup",
6348         [BTRFS_RAID_RAID0]      = "raid0",
6349         [BTRFS_RAID_SINGLE]     = "single",
6350         [BTRFS_RAID_RAID5]      = "raid5",
6351         [BTRFS_RAID_RAID6]      = "raid6",
6352 };
6353
6354 static const char *get_raid_name(enum btrfs_raid_types type)
6355 {
6356         if (type >= BTRFS_NR_RAID_TYPES)
6357                 return NULL;
6358
6359         return btrfs_raid_type_names[type];
6360 }
6361
6362 enum btrfs_loop_type {
6363         LOOP_CACHING_NOWAIT = 0,
6364         LOOP_CACHING_WAIT = 1,
6365         LOOP_ALLOC_CHUNK = 2,
6366         LOOP_NO_EMPTY_SIZE = 3,
6367 };
6368
6369 static inline void
6370 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
6371                        int delalloc)
6372 {
6373         if (delalloc)
6374                 down_read(&cache->data_rwsem);
6375 }
6376
6377 static inline void
6378 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
6379                        int delalloc)
6380 {
6381         btrfs_get_block_group(cache);
6382         if (delalloc)
6383                 down_read(&cache->data_rwsem);
6384 }
6385
6386 static struct btrfs_block_group_cache *
6387 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
6388                    struct btrfs_free_cluster *cluster,
6389                    int delalloc)
6390 {
6391         struct btrfs_block_group_cache *used_bg;
6392         bool locked = false;
6393 again:
6394         spin_lock(&cluster->refill_lock);
6395         if (locked) {
6396                 if (used_bg == cluster->block_group)
6397                         return used_bg;
6398
6399                 up_read(&used_bg->data_rwsem);
6400                 btrfs_put_block_group(used_bg);
6401         }
6402
6403         used_bg = cluster->block_group;
6404         if (!used_bg)
6405                 return NULL;
6406
6407         if (used_bg == block_group)
6408                 return used_bg;
6409
6410         btrfs_get_block_group(used_bg);
6411
6412         if (!delalloc)
6413                 return used_bg;
6414
6415         if (down_read_trylock(&used_bg->data_rwsem))
6416                 return used_bg;
6417
6418         spin_unlock(&cluster->refill_lock);
6419         down_read(&used_bg->data_rwsem);
6420         locked = true;
6421         goto again;
6422 }
6423
6424 static inline void
6425 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
6426                          int delalloc)
6427 {
6428         if (delalloc)
6429                 up_read(&cache->data_rwsem);
6430         btrfs_put_block_group(cache);
6431 }
6432
6433 /*
6434  * walks the btree of allocated extents and find a hole of a given size.
6435  * The key ins is changed to record the hole:
6436  * ins->objectid == start position
6437  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6438  * ins->offset == the size of the hole.
6439  * Any available blocks before search_start are skipped.
6440  *
6441  * If there is no suitable free space, we will record the max size of
6442  * the free space extent currently.
6443  */
6444 static noinline int find_free_extent(struct btrfs_root *orig_root,
6445                                      u64 num_bytes, u64 empty_size,
6446                                      u64 hint_byte, struct btrfs_key *ins,
6447                                      u64 flags, int delalloc)
6448 {
6449         int ret = 0;
6450         struct btrfs_root *root = orig_root->fs_info->extent_root;
6451         struct btrfs_free_cluster *last_ptr = NULL;
6452         struct btrfs_block_group_cache *block_group = NULL;
6453         u64 search_start = 0;
6454         u64 max_extent_size = 0;
6455         int empty_cluster = 2 * 1024 * 1024;
6456         struct btrfs_space_info *space_info;
6457         int loop = 0;
6458         int index = __get_raid_index(flags);
6459         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6460                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6461         bool failed_cluster_refill = false;
6462         bool failed_alloc = false;
6463         bool use_cluster = true;
6464         bool have_caching_bg = false;
6465
6466         WARN_ON(num_bytes < root->sectorsize);
6467         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
6468         ins->objectid = 0;
6469         ins->offset = 0;
6470
6471         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6472
6473         space_info = __find_space_info(root->fs_info, flags);
6474         if (!space_info) {
6475                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6476                 return -ENOSPC;
6477         }
6478
6479         /*
6480          * If the space info is for both data and metadata it means we have a
6481          * small filesystem and we can't use the clustering stuff.
6482          */
6483         if (btrfs_mixed_space_info(space_info))
6484                 use_cluster = false;
6485
6486         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6487                 last_ptr = &root->fs_info->meta_alloc_cluster;
6488                 if (!btrfs_test_opt(root, SSD))
6489                         empty_cluster = 64 * 1024;
6490         }
6491
6492         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6493             btrfs_test_opt(root, SSD)) {
6494                 last_ptr = &root->fs_info->data_alloc_cluster;
6495         }
6496
6497         if (last_ptr) {
6498                 spin_lock(&last_ptr->lock);
6499                 if (last_ptr->block_group)
6500                         hint_byte = last_ptr->window_start;
6501                 spin_unlock(&last_ptr->lock);
6502         }
6503
6504         search_start = max(search_start, first_logical_byte(root, 0));
6505         search_start = max(search_start, hint_byte);
6506
6507         if (!last_ptr)
6508                 empty_cluster = 0;
6509
6510         if (search_start == hint_byte) {
6511                 block_group = btrfs_lookup_block_group(root->fs_info,
6512                                                        search_start);
6513                 /*
6514                  * we don't want to use the block group if it doesn't match our
6515                  * allocation bits, or if its not cached.
6516                  *
6517                  * However if we are re-searching with an ideal block group
6518                  * picked out then we don't care that the block group is cached.
6519                  */
6520                 if (block_group && block_group_bits(block_group, flags) &&
6521                     block_group->cached != BTRFS_CACHE_NO) {
6522                         down_read(&space_info->groups_sem);
6523                         if (list_empty(&block_group->list) ||
6524                             block_group->ro) {
6525                                 /*
6526                                  * someone is removing this block group,
6527                                  * we can't jump into the have_block_group
6528                                  * target because our list pointers are not
6529                                  * valid
6530                                  */
6531                                 btrfs_put_block_group(block_group);
6532                                 up_read(&space_info->groups_sem);
6533                         } else {
6534                                 index = get_block_group_index(block_group);
6535                                 btrfs_lock_block_group(block_group, delalloc);
6536                                 goto have_block_group;
6537                         }
6538                 } else if (block_group) {
6539                         btrfs_put_block_group(block_group);
6540                 }
6541         }
6542 search:
6543         have_caching_bg = false;
6544         down_read(&space_info->groups_sem);
6545         list_for_each_entry(block_group, &space_info->block_groups[index],
6546                             list) {
6547                 u64 offset;
6548                 int cached;
6549
6550                 btrfs_grab_block_group(block_group, delalloc);
6551                 search_start = block_group->key.objectid;
6552
6553                 /*
6554                  * this can happen if we end up cycling through all the
6555                  * raid types, but we want to make sure we only allocate
6556                  * for the proper type.
6557                  */
6558                 if (!block_group_bits(block_group, flags)) {
6559                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6560                                 BTRFS_BLOCK_GROUP_RAID1 |
6561                                 BTRFS_BLOCK_GROUP_RAID5 |
6562                                 BTRFS_BLOCK_GROUP_RAID6 |
6563                                 BTRFS_BLOCK_GROUP_RAID10;
6564
6565                         /*
6566                          * if they asked for extra copies and this block group
6567                          * doesn't provide them, bail.  This does allow us to
6568                          * fill raid0 from raid1.
6569                          */
6570                         if ((flags & extra) && !(block_group->flags & extra))
6571                                 goto loop;
6572                 }
6573
6574 have_block_group:
6575                 cached = block_group_cache_done(block_group);
6576                 if (unlikely(!cached)) {
6577                         ret = cache_block_group(block_group, 0);
6578                         BUG_ON(ret < 0);
6579                         ret = 0;
6580                 }
6581
6582                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
6583                         goto loop;
6584                 if (unlikely(block_group->ro))
6585                         goto loop;
6586
6587                 /*
6588                  * Ok we want to try and use the cluster allocator, so
6589                  * lets look there
6590                  */
6591                 if (last_ptr) {
6592                         struct btrfs_block_group_cache *used_block_group;
6593                         unsigned long aligned_cluster;
6594                         /*
6595                          * the refill lock keeps out other
6596                          * people trying to start a new cluster
6597                          */
6598                         used_block_group = btrfs_lock_cluster(block_group,
6599                                                               last_ptr,
6600                                                               delalloc);
6601                         if (!used_block_group)
6602                                 goto refill_cluster;
6603
6604                         if (used_block_group != block_group &&
6605                             (used_block_group->ro ||
6606                              !block_group_bits(used_block_group, flags)))
6607                                 goto release_cluster;
6608
6609                         offset = btrfs_alloc_from_cluster(used_block_group,
6610                                                 last_ptr,
6611                                                 num_bytes,
6612                                                 used_block_group->key.objectid,
6613                                                 &max_extent_size);
6614                         if (offset) {
6615                                 /* we have a block, we're done */
6616                                 spin_unlock(&last_ptr->refill_lock);
6617                                 trace_btrfs_reserve_extent_cluster(root,
6618                                                 used_block_group,
6619                                                 search_start, num_bytes);
6620                                 if (used_block_group != block_group) {
6621                                         btrfs_release_block_group(block_group,
6622                                                                   delalloc);
6623                                         block_group = used_block_group;
6624                                 }
6625                                 goto checks;
6626                         }
6627
6628                         WARN_ON(last_ptr->block_group != used_block_group);
6629 release_cluster:
6630                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6631                          * set up a new clusters, so lets just skip it
6632                          * and let the allocator find whatever block
6633                          * it can find.  If we reach this point, we
6634                          * will have tried the cluster allocator
6635                          * plenty of times and not have found
6636                          * anything, so we are likely way too
6637                          * fragmented for the clustering stuff to find
6638                          * anything.
6639                          *
6640                          * However, if the cluster is taken from the
6641                          * current block group, release the cluster
6642                          * first, so that we stand a better chance of
6643                          * succeeding in the unclustered
6644                          * allocation.  */
6645                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6646                             used_block_group != block_group) {
6647                                 spin_unlock(&last_ptr->refill_lock);
6648                                 btrfs_release_block_group(used_block_group,
6649                                                           delalloc);
6650                                 goto unclustered_alloc;
6651                         }
6652
6653                         /*
6654                          * this cluster didn't work out, free it and
6655                          * start over
6656                          */
6657                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6658
6659                         if (used_block_group != block_group)
6660                                 btrfs_release_block_group(used_block_group,
6661                                                           delalloc);
6662 refill_cluster:
6663                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6664                                 spin_unlock(&last_ptr->refill_lock);
6665                                 goto unclustered_alloc;
6666                         }
6667
6668                         aligned_cluster = max_t(unsigned long,
6669                                                 empty_cluster + empty_size,
6670                                               block_group->full_stripe_len);
6671
6672                         /* allocate a cluster in this block group */
6673                         ret = btrfs_find_space_cluster(root, block_group,
6674                                                        last_ptr, search_start,
6675                                                        num_bytes,
6676                                                        aligned_cluster);
6677                         if (ret == 0) {
6678                                 /*
6679                                  * now pull our allocation out of this
6680                                  * cluster
6681                                  */
6682                                 offset = btrfs_alloc_from_cluster(block_group,
6683                                                         last_ptr,
6684                                                         num_bytes,
6685                                                         search_start,
6686                                                         &max_extent_size);
6687                                 if (offset) {
6688                                         /* we found one, proceed */
6689                                         spin_unlock(&last_ptr->refill_lock);
6690                                         trace_btrfs_reserve_extent_cluster(root,
6691                                                 block_group, search_start,
6692                                                 num_bytes);
6693                                         goto checks;
6694                                 }
6695                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6696                                    && !failed_cluster_refill) {
6697                                 spin_unlock(&last_ptr->refill_lock);
6698
6699                                 failed_cluster_refill = true;
6700                                 wait_block_group_cache_progress(block_group,
6701                                        num_bytes + empty_cluster + empty_size);
6702                                 goto have_block_group;
6703                         }
6704
6705                         /*
6706                          * at this point we either didn't find a cluster
6707                          * or we weren't able to allocate a block from our
6708                          * cluster.  Free the cluster we've been trying
6709                          * to use, and go to the next block group
6710                          */
6711                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6712                         spin_unlock(&last_ptr->refill_lock);
6713                         goto loop;
6714                 }
6715
6716 unclustered_alloc:
6717                 spin_lock(&block_group->free_space_ctl->tree_lock);
6718                 if (cached &&
6719                     block_group->free_space_ctl->free_space <
6720                     num_bytes + empty_cluster + empty_size) {
6721                         if (block_group->free_space_ctl->free_space >
6722                             max_extent_size)
6723                                 max_extent_size =
6724                                         block_group->free_space_ctl->free_space;
6725                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6726                         goto loop;
6727                 }
6728                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6729
6730                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6731                                                     num_bytes, empty_size,
6732                                                     &max_extent_size);
6733                 /*
6734                  * If we didn't find a chunk, and we haven't failed on this
6735                  * block group before, and this block group is in the middle of
6736                  * caching and we are ok with waiting, then go ahead and wait
6737                  * for progress to be made, and set failed_alloc to true.
6738                  *
6739                  * If failed_alloc is true then we've already waited on this
6740                  * block group once and should move on to the next block group.
6741                  */
6742                 if (!offset && !failed_alloc && !cached &&
6743                     loop > LOOP_CACHING_NOWAIT) {
6744                         wait_block_group_cache_progress(block_group,
6745                                                 num_bytes + empty_size);
6746                         failed_alloc = true;
6747                         goto have_block_group;
6748                 } else if (!offset) {
6749                         if (!cached)
6750                                 have_caching_bg = true;
6751                         goto loop;
6752                 }
6753 checks:
6754                 search_start = stripe_align(root, block_group,
6755                                             offset, num_bytes);
6756
6757                 /* move on to the next group */
6758                 if (search_start + num_bytes >
6759                     block_group->key.objectid + block_group->key.offset) {
6760                         btrfs_add_free_space(block_group, offset, num_bytes);
6761                         goto loop;
6762                 }
6763
6764                 if (offset < search_start)
6765                         btrfs_add_free_space(block_group, offset,
6766                                              search_start - offset);
6767                 BUG_ON(offset > search_start);
6768
6769                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
6770                                                   alloc_type, delalloc);
6771                 if (ret == -EAGAIN) {
6772                         btrfs_add_free_space(block_group, offset, num_bytes);
6773                         goto loop;
6774                 }
6775
6776                 /* we are all good, lets return */
6777                 ins->objectid = search_start;
6778                 ins->offset = num_bytes;
6779
6780                 trace_btrfs_reserve_extent(orig_root, block_group,
6781                                            search_start, num_bytes);
6782                 btrfs_release_block_group(block_group, delalloc);
6783                 break;
6784 loop:
6785                 failed_cluster_refill = false;
6786                 failed_alloc = false;
6787                 BUG_ON(index != get_block_group_index(block_group));
6788                 btrfs_release_block_group(block_group, delalloc);
6789         }
6790         up_read(&space_info->groups_sem);
6791
6792         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6793                 goto search;
6794
6795         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6796                 goto search;
6797
6798         /*
6799          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6800          *                      caching kthreads as we move along
6801          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6802          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6803          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6804          *                      again
6805          */
6806         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6807                 index = 0;
6808                 loop++;
6809                 if (loop == LOOP_ALLOC_CHUNK) {
6810                         struct btrfs_trans_handle *trans;
6811                         int exist = 0;
6812
6813                         trans = current->journal_info;
6814                         if (trans)
6815                                 exist = 1;
6816                         else
6817                                 trans = btrfs_join_transaction(root);
6818
6819                         if (IS_ERR(trans)) {
6820                                 ret = PTR_ERR(trans);
6821                                 goto out;
6822                         }
6823
6824                         ret = do_chunk_alloc(trans, root, flags,
6825                                              CHUNK_ALLOC_FORCE);
6826                         /*
6827                          * Do not bail out on ENOSPC since we
6828                          * can do more things.
6829                          */
6830                         if (ret < 0 && ret != -ENOSPC)
6831                                 btrfs_abort_transaction(trans,
6832                                                         root, ret);
6833                         else
6834                                 ret = 0;
6835                         if (!exist)
6836                                 btrfs_end_transaction(trans, root);
6837                         if (ret)
6838                                 goto out;
6839                 }
6840
6841                 if (loop == LOOP_NO_EMPTY_SIZE) {
6842                         empty_size = 0;
6843                         empty_cluster = 0;
6844                 }
6845
6846                 goto search;
6847         } else if (!ins->objectid) {
6848                 ret = -ENOSPC;
6849         } else if (ins->objectid) {
6850                 ret = 0;
6851         }
6852 out:
6853         if (ret == -ENOSPC)
6854                 ins->offset = max_extent_size;
6855         return ret;
6856 }
6857
6858 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6859                             int dump_block_groups)
6860 {
6861         struct btrfs_block_group_cache *cache;
6862         int index = 0;
6863
6864         spin_lock(&info->lock);
6865         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
6866                info->flags,
6867                info->total_bytes - info->bytes_used - info->bytes_pinned -
6868                info->bytes_reserved - info->bytes_readonly,
6869                (info->full) ? "" : "not ");
6870         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
6871                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6872                info->total_bytes, info->bytes_used, info->bytes_pinned,
6873                info->bytes_reserved, info->bytes_may_use,
6874                info->bytes_readonly);
6875         spin_unlock(&info->lock);
6876
6877         if (!dump_block_groups)
6878                 return;
6879
6880         down_read(&info->groups_sem);
6881 again:
6882         list_for_each_entry(cache, &info->block_groups[index], list) {
6883                 spin_lock(&cache->lock);
6884                 printk(KERN_INFO "BTRFS: "
6885                            "block group %llu has %llu bytes, "
6886                            "%llu used %llu pinned %llu reserved %s\n",
6887                        cache->key.objectid, cache->key.offset,
6888                        btrfs_block_group_used(&cache->item), cache->pinned,
6889                        cache->reserved, cache->ro ? "[readonly]" : "");
6890                 btrfs_dump_free_space(cache, bytes);
6891                 spin_unlock(&cache->lock);
6892         }
6893         if (++index < BTRFS_NR_RAID_TYPES)
6894                 goto again;
6895         up_read(&info->groups_sem);
6896 }
6897
6898 int btrfs_reserve_extent(struct btrfs_root *root,
6899                          u64 num_bytes, u64 min_alloc_size,
6900                          u64 empty_size, u64 hint_byte,
6901                          struct btrfs_key *ins, int is_data, int delalloc)
6902 {
6903         bool final_tried = false;
6904         u64 flags;
6905         int ret;
6906
6907         flags = btrfs_get_alloc_profile(root, is_data);
6908 again:
6909         WARN_ON(num_bytes < root->sectorsize);
6910         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
6911                                flags, delalloc);
6912
6913         if (ret == -ENOSPC) {
6914                 if (!final_tried && ins->offset) {
6915                         num_bytes = min(num_bytes >> 1, ins->offset);
6916                         num_bytes = round_down(num_bytes, root->sectorsize);
6917                         num_bytes = max(num_bytes, min_alloc_size);
6918                         if (num_bytes == min_alloc_size)
6919                                 final_tried = true;
6920                         goto again;
6921                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6922                         struct btrfs_space_info *sinfo;
6923
6924                         sinfo = __find_space_info(root->fs_info, flags);
6925                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
6926                                 flags, num_bytes);
6927                         if (sinfo)
6928                                 dump_space_info(sinfo, num_bytes, 1);
6929                 }
6930         }
6931
6932         return ret;
6933 }
6934
6935 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6936                                         u64 start, u64 len,
6937                                         int pin, int delalloc)
6938 {
6939         struct btrfs_block_group_cache *cache;
6940         int ret = 0;
6941
6942         cache = btrfs_lookup_block_group(root->fs_info, start);
6943         if (!cache) {
6944                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
6945                         start);
6946                 return -ENOSPC;
6947         }
6948
6949         if (btrfs_test_opt(root, DISCARD))
6950                 ret = btrfs_discard_extent(root, start, len, NULL);
6951
6952         if (pin)
6953                 pin_down_extent(root, cache, start, len, 1);
6954         else {
6955                 btrfs_add_free_space(cache, start, len);
6956                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
6957         }
6958         btrfs_put_block_group(cache);
6959
6960         trace_btrfs_reserved_extent_free(root, start, len);
6961
6962         return ret;
6963 }
6964
6965 int btrfs_free_reserved_extent(struct btrfs_root *root,
6966                                u64 start, u64 len, int delalloc)
6967 {
6968         return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
6969 }
6970
6971 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6972                                        u64 start, u64 len)
6973 {
6974         return __btrfs_free_reserved_extent(root, start, len, 1, 0);
6975 }
6976
6977 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6978                                       struct btrfs_root *root,
6979                                       u64 parent, u64 root_objectid,
6980                                       u64 flags, u64 owner, u64 offset,
6981                                       struct btrfs_key *ins, int ref_mod)
6982 {
6983         int ret;
6984         struct btrfs_fs_info *fs_info = root->fs_info;
6985         struct btrfs_extent_item *extent_item;
6986         struct btrfs_extent_inline_ref *iref;
6987         struct btrfs_path *path;
6988         struct extent_buffer *leaf;
6989         int type;
6990         u32 size;
6991
6992         if (parent > 0)
6993                 type = BTRFS_SHARED_DATA_REF_KEY;
6994         else
6995                 type = BTRFS_EXTENT_DATA_REF_KEY;
6996
6997         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6998
6999         path = btrfs_alloc_path();
7000         if (!path)
7001                 return -ENOMEM;
7002
7003         path->leave_spinning = 1;
7004         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7005                                       ins, size);
7006         if (ret) {
7007                 btrfs_free_path(path);
7008                 return ret;
7009         }
7010
7011         leaf = path->nodes[0];
7012         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7013                                      struct btrfs_extent_item);
7014         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7015         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7016         btrfs_set_extent_flags(leaf, extent_item,
7017                                flags | BTRFS_EXTENT_FLAG_DATA);
7018
7019         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7020         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7021         if (parent > 0) {
7022                 struct btrfs_shared_data_ref *ref;
7023                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7024                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7025                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7026         } else {
7027                 struct btrfs_extent_data_ref *ref;
7028                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7029                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7030                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7031                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7032                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7033         }
7034
7035         btrfs_mark_buffer_dirty(path->nodes[0]);
7036         btrfs_free_path(path);
7037
7038         /* Always set parent to 0 here since its exclusive anyway. */
7039         ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
7040                                       ins->objectid, ins->offset,
7041                                       BTRFS_QGROUP_OPER_ADD_EXCL, 0);
7042         if (ret)
7043                 return ret;
7044
7045         ret = update_block_group(root, ins->objectid, ins->offset, 1);
7046         if (ret) { /* -ENOENT, logic error */
7047                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7048                         ins->objectid, ins->offset);
7049                 BUG();
7050         }
7051         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
7052         return ret;
7053 }
7054
7055 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7056                                      struct btrfs_root *root,
7057                                      u64 parent, u64 root_objectid,
7058                                      u64 flags, struct btrfs_disk_key *key,
7059                                      int level, struct btrfs_key *ins,
7060                                      int no_quota)
7061 {
7062         int ret;
7063         struct btrfs_fs_info *fs_info = root->fs_info;
7064         struct btrfs_extent_item *extent_item;
7065         struct btrfs_tree_block_info *block_info;
7066         struct btrfs_extent_inline_ref *iref;
7067         struct btrfs_path *path;
7068         struct extent_buffer *leaf;
7069         u32 size = sizeof(*extent_item) + sizeof(*iref);
7070         u64 num_bytes = ins->offset;
7071         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7072                                                  SKINNY_METADATA);
7073
7074         if (!skinny_metadata)
7075                 size += sizeof(*block_info);
7076
7077         path = btrfs_alloc_path();
7078         if (!path) {
7079                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7080                                                    root->leafsize);
7081                 return -ENOMEM;
7082         }
7083
7084         path->leave_spinning = 1;
7085         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7086                                       ins, size);
7087         if (ret) {
7088                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7089                                                    root->leafsize);
7090                 btrfs_free_path(path);
7091                 return ret;
7092         }
7093
7094         leaf = path->nodes[0];
7095         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7096                                      struct btrfs_extent_item);
7097         btrfs_set_extent_refs(leaf, extent_item, 1);
7098         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7099         btrfs_set_extent_flags(leaf, extent_item,
7100                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
7101
7102         if (skinny_metadata) {
7103                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7104                 num_bytes = root->leafsize;
7105         } else {
7106                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
7107                 btrfs_set_tree_block_key(leaf, block_info, key);
7108                 btrfs_set_tree_block_level(leaf, block_info, level);
7109                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
7110         }
7111
7112         if (parent > 0) {
7113                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
7114                 btrfs_set_extent_inline_ref_type(leaf, iref,
7115                                                  BTRFS_SHARED_BLOCK_REF_KEY);
7116                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7117         } else {
7118                 btrfs_set_extent_inline_ref_type(leaf, iref,
7119                                                  BTRFS_TREE_BLOCK_REF_KEY);
7120                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
7121         }
7122
7123         btrfs_mark_buffer_dirty(leaf);
7124         btrfs_free_path(path);
7125
7126         if (!no_quota) {
7127                 ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
7128                                               ins->objectid, num_bytes,
7129                                               BTRFS_QGROUP_OPER_ADD_EXCL, 0);
7130                 if (ret)
7131                         return ret;
7132         }
7133
7134         ret = update_block_group(root, ins->objectid, root->leafsize, 1);
7135         if (ret) { /* -ENOENT, logic error */
7136                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7137                         ins->objectid, ins->offset);
7138                 BUG();
7139         }
7140
7141         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->leafsize);
7142         return ret;
7143 }
7144
7145 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7146                                      struct btrfs_root *root,
7147                                      u64 root_objectid, u64 owner,
7148                                      u64 offset, struct btrfs_key *ins)
7149 {
7150         int ret;
7151
7152         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
7153
7154         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
7155                                          ins->offset, 0,
7156                                          root_objectid, owner, offset,
7157                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
7158         return ret;
7159 }
7160
7161 /*
7162  * this is used by the tree logging recovery code.  It records that
7163  * an extent has been allocated and makes sure to clear the free
7164  * space cache bits as well
7165  */
7166 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
7167                                    struct btrfs_root *root,
7168                                    u64 root_objectid, u64 owner, u64 offset,
7169                                    struct btrfs_key *ins)
7170 {
7171         int ret;
7172         struct btrfs_block_group_cache *block_group;
7173
7174         /*
7175          * Mixed block groups will exclude before processing the log so we only
7176          * need to do the exlude dance if this fs isn't mixed.
7177          */
7178         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
7179                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
7180                 if (ret)
7181                         return ret;
7182         }
7183
7184         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
7185         if (!block_group)
7186                 return -EINVAL;
7187
7188         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
7189                                           RESERVE_ALLOC_NO_ACCOUNT, 0);
7190         BUG_ON(ret); /* logic error */
7191         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
7192                                          0, owner, offset, ins, 1);
7193         btrfs_put_block_group(block_group);
7194         return ret;
7195 }
7196
7197 static struct extent_buffer *
7198 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7199                       u64 bytenr, u32 blocksize, int level)
7200 {
7201         struct extent_buffer *buf;
7202
7203         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
7204         if (!buf)
7205                 return ERR_PTR(-ENOMEM);
7206         btrfs_set_header_generation(buf, trans->transid);
7207         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
7208         btrfs_tree_lock(buf);
7209         clean_tree_block(trans, root, buf);
7210         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
7211
7212         btrfs_set_lock_blocking(buf);
7213         btrfs_set_buffer_uptodate(buf);
7214
7215         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
7216                 /*
7217                  * we allow two log transactions at a time, use different
7218                  * EXENT bit to differentiate dirty pages.
7219                  */
7220                 if (root->log_transid % 2 == 0)
7221                         set_extent_dirty(&root->dirty_log_pages, buf->start,
7222                                         buf->start + buf->len - 1, GFP_NOFS);
7223                 else
7224                         set_extent_new(&root->dirty_log_pages, buf->start,
7225                                         buf->start + buf->len - 1, GFP_NOFS);
7226         } else {
7227                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
7228                          buf->start + buf->len - 1, GFP_NOFS);
7229         }
7230         trans->blocks_used++;
7231         /* this returns a buffer locked for blocking */
7232         return buf;
7233 }
7234
7235 static struct btrfs_block_rsv *
7236 use_block_rsv(struct btrfs_trans_handle *trans,
7237               struct btrfs_root *root, u32 blocksize)
7238 {
7239         struct btrfs_block_rsv *block_rsv;
7240         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
7241         int ret;
7242         bool global_updated = false;
7243
7244         block_rsv = get_block_rsv(trans, root);
7245
7246         if (unlikely(block_rsv->size == 0))
7247                 goto try_reserve;
7248 again:
7249         ret = block_rsv_use_bytes(block_rsv, blocksize);
7250         if (!ret)
7251                 return block_rsv;
7252
7253         if (block_rsv->failfast)
7254                 return ERR_PTR(ret);
7255
7256         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
7257                 global_updated = true;
7258                 update_global_block_rsv(root->fs_info);
7259                 goto again;
7260         }
7261
7262         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7263                 static DEFINE_RATELIMIT_STATE(_rs,
7264                                 DEFAULT_RATELIMIT_INTERVAL * 10,
7265                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
7266                 if (__ratelimit(&_rs))
7267                         WARN(1, KERN_DEBUG
7268                                 "BTRFS: block rsv returned %d\n", ret);
7269         }
7270 try_reserve:
7271         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
7272                                      BTRFS_RESERVE_NO_FLUSH);
7273         if (!ret)
7274                 return block_rsv;
7275         /*
7276          * If we couldn't reserve metadata bytes try and use some from
7277          * the global reserve if its space type is the same as the global
7278          * reservation.
7279          */
7280         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
7281             block_rsv->space_info == global_rsv->space_info) {
7282                 ret = block_rsv_use_bytes(global_rsv, blocksize);
7283                 if (!ret)
7284                         return global_rsv;
7285         }
7286         return ERR_PTR(ret);
7287 }
7288
7289 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
7290                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
7291 {
7292         block_rsv_add_bytes(block_rsv, blocksize, 0);
7293         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
7294 }
7295
7296 /*
7297  * finds a free extent and does all the dirty work required for allocation
7298  * returns the key for the extent through ins, and a tree buffer for
7299  * the first block of the extent through buf.
7300  *
7301  * returns the tree buffer or NULL.
7302  */
7303 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
7304                                         struct btrfs_root *root, u32 blocksize,
7305                                         u64 parent, u64 root_objectid,
7306                                         struct btrfs_disk_key *key, int level,
7307                                         u64 hint, u64 empty_size)
7308 {
7309         struct btrfs_key ins;
7310         struct btrfs_block_rsv *block_rsv;
7311         struct extent_buffer *buf;
7312         u64 flags = 0;
7313         int ret;
7314         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7315                                                  SKINNY_METADATA);
7316
7317 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
7318         if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state))) {
7319                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
7320                                             blocksize, level);
7321                 if (!IS_ERR(buf))
7322                         root->alloc_bytenr += blocksize;
7323                 return buf;
7324         }
7325 #endif
7326         block_rsv = use_block_rsv(trans, root, blocksize);
7327         if (IS_ERR(block_rsv))
7328                 return ERR_CAST(block_rsv);
7329
7330         ret = btrfs_reserve_extent(root, blocksize, blocksize,
7331                                    empty_size, hint, &ins, 0, 0);
7332         if (ret) {
7333                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
7334                 return ERR_PTR(ret);
7335         }
7336
7337         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
7338                                     blocksize, level);
7339         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
7340
7341         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
7342                 if (parent == 0)
7343                         parent = ins.objectid;
7344                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
7345         } else
7346                 BUG_ON(parent > 0);
7347
7348         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
7349                 struct btrfs_delayed_extent_op *extent_op;
7350                 extent_op = btrfs_alloc_delayed_extent_op();
7351                 BUG_ON(!extent_op); /* -ENOMEM */
7352                 if (key)
7353                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
7354                 else
7355                         memset(&extent_op->key, 0, sizeof(extent_op->key));
7356                 extent_op->flags_to_set = flags;
7357                 if (skinny_metadata)
7358                         extent_op->update_key = 0;
7359                 else
7360                         extent_op->update_key = 1;
7361                 extent_op->update_flags = 1;
7362                 extent_op->is_data = 0;
7363                 extent_op->level = level;
7364
7365                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7366                                         ins.objectid,
7367                                         ins.offset, parent, root_objectid,
7368                                         level, BTRFS_ADD_DELAYED_EXTENT,
7369                                         extent_op, 0);
7370                 BUG_ON(ret); /* -ENOMEM */
7371         }
7372         return buf;
7373 }
7374
7375 struct walk_control {
7376         u64 refs[BTRFS_MAX_LEVEL];
7377         u64 flags[BTRFS_MAX_LEVEL];
7378         struct btrfs_key update_progress;
7379         int stage;
7380         int level;
7381         int shared_level;
7382         int update_ref;
7383         int keep_locks;
7384         int reada_slot;
7385         int reada_count;
7386         int for_reloc;
7387 };
7388
7389 #define DROP_REFERENCE  1
7390 #define UPDATE_BACKREF  2
7391
7392 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7393                                      struct btrfs_root *root,
7394                                      struct walk_control *wc,
7395                                      struct btrfs_path *path)
7396 {
7397         u64 bytenr;
7398         u64 generation;
7399         u64 refs;
7400         u64 flags;
7401         u32 nritems;
7402         u32 blocksize;
7403         struct btrfs_key key;
7404         struct extent_buffer *eb;
7405         int ret;
7406         int slot;
7407         int nread = 0;
7408
7409         if (path->slots[wc->level] < wc->reada_slot) {
7410                 wc->reada_count = wc->reada_count * 2 / 3;
7411                 wc->reada_count = max(wc->reada_count, 2);
7412         } else {
7413                 wc->reada_count = wc->reada_count * 3 / 2;
7414                 wc->reada_count = min_t(int, wc->reada_count,
7415                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7416         }
7417
7418         eb = path->nodes[wc->level];
7419         nritems = btrfs_header_nritems(eb);
7420         blocksize = btrfs_level_size(root, wc->level - 1);
7421
7422         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7423                 if (nread >= wc->reada_count)
7424                         break;
7425
7426                 cond_resched();
7427                 bytenr = btrfs_node_blockptr(eb, slot);
7428                 generation = btrfs_node_ptr_generation(eb, slot);
7429
7430                 if (slot == path->slots[wc->level])
7431                         goto reada;
7432
7433                 if (wc->stage == UPDATE_BACKREF &&
7434                     generation <= root->root_key.offset)
7435                         continue;
7436
7437                 /* We don't lock the tree block, it's OK to be racy here */
7438                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7439                                                wc->level - 1, 1, &refs,
7440                                                &flags);
7441                 /* We don't care about errors in readahead. */
7442                 if (ret < 0)
7443                         continue;
7444                 BUG_ON(refs == 0);
7445
7446                 if (wc->stage == DROP_REFERENCE) {
7447                         if (refs == 1)
7448                                 goto reada;
7449
7450                         if (wc->level == 1 &&
7451                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7452                                 continue;
7453                         if (!wc->update_ref ||
7454                             generation <= root->root_key.offset)
7455                                 continue;
7456                         btrfs_node_key_to_cpu(eb, &key, slot);
7457                         ret = btrfs_comp_cpu_keys(&key,
7458                                                   &wc->update_progress);
7459                         if (ret < 0)
7460                                 continue;
7461                 } else {
7462                         if (wc->level == 1 &&
7463                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7464                                 continue;
7465                 }
7466 reada:
7467                 ret = readahead_tree_block(root, bytenr, blocksize,
7468                                            generation);
7469                 if (ret)
7470                         break;
7471                 nread++;
7472         }
7473         wc->reada_slot = slot;
7474 }
7475
7476 static int account_leaf_items(struct btrfs_trans_handle *trans,
7477                               struct btrfs_root *root,
7478                               struct extent_buffer *eb)
7479 {
7480         int nr = btrfs_header_nritems(eb);
7481         int i, extent_type, ret;
7482         struct btrfs_key key;
7483         struct btrfs_file_extent_item *fi;
7484         u64 bytenr, num_bytes;
7485
7486         for (i = 0; i < nr; i++) {
7487                 btrfs_item_key_to_cpu(eb, &key, i);
7488
7489                 if (key.type != BTRFS_EXTENT_DATA_KEY)
7490                         continue;
7491
7492                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
7493                 /* filter out non qgroup-accountable extents  */
7494                 extent_type = btrfs_file_extent_type(eb, fi);
7495
7496                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
7497                         continue;
7498
7499                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
7500                 if (!bytenr)
7501                         continue;
7502
7503                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
7504
7505                 ret = btrfs_qgroup_record_ref(trans, root->fs_info,
7506                                               root->objectid,
7507                                               bytenr, num_bytes,
7508                                               BTRFS_QGROUP_OPER_SUB_SUBTREE, 0);
7509                 if (ret)
7510                         return ret;
7511         }
7512         return 0;
7513 }
7514
7515 /*
7516  * Walk up the tree from the bottom, freeing leaves and any interior
7517  * nodes which have had all slots visited. If a node (leaf or
7518  * interior) is freed, the node above it will have it's slot
7519  * incremented. The root node will never be freed.
7520  *
7521  * At the end of this function, we should have a path which has all
7522  * slots incremented to the next position for a search. If we need to
7523  * read a new node it will be NULL and the node above it will have the
7524  * correct slot selected for a later read.
7525  *
7526  * If we increment the root nodes slot counter past the number of
7527  * elements, 1 is returned to signal completion of the search.
7528  */
7529 static int adjust_slots_upwards(struct btrfs_root *root,
7530                                 struct btrfs_path *path, int root_level)
7531 {
7532         int level = 0;
7533         int nr, slot;
7534         struct extent_buffer *eb;
7535
7536         if (root_level == 0)
7537                 return 1;
7538
7539         while (level <= root_level) {
7540                 eb = path->nodes[level];
7541                 nr = btrfs_header_nritems(eb);
7542                 path->slots[level]++;
7543                 slot = path->slots[level];
7544                 if (slot >= nr || level == 0) {
7545                         /*
7546                          * Don't free the root -  we will detect this
7547                          * condition after our loop and return a
7548                          * positive value for caller to stop walking the tree.
7549                          */
7550                         if (level != root_level) {
7551                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7552                                 path->locks[level] = 0;
7553
7554                                 free_extent_buffer(eb);
7555                                 path->nodes[level] = NULL;
7556                                 path->slots[level] = 0;
7557                         }
7558                 } else {
7559                         /*
7560                          * We have a valid slot to walk back down
7561                          * from. Stop here so caller can process these
7562                          * new nodes.
7563                          */
7564                         break;
7565                 }
7566
7567                 level++;
7568         }
7569
7570         eb = path->nodes[root_level];
7571         if (path->slots[root_level] >= btrfs_header_nritems(eb))
7572                 return 1;
7573
7574         return 0;
7575 }
7576
7577 /*
7578  * root_eb is the subtree root and is locked before this function is called.
7579  */
7580 static int account_shared_subtree(struct btrfs_trans_handle *trans,
7581                                   struct btrfs_root *root,
7582                                   struct extent_buffer *root_eb,
7583                                   u64 root_gen,
7584                                   int root_level)
7585 {
7586         int ret = 0;
7587         int level;
7588         struct extent_buffer *eb = root_eb;
7589         struct btrfs_path *path = NULL;
7590
7591         BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
7592         BUG_ON(root_eb == NULL);
7593
7594         if (!root->fs_info->quota_enabled)
7595                 return 0;
7596
7597         if (!extent_buffer_uptodate(root_eb)) {
7598                 ret = btrfs_read_buffer(root_eb, root_gen);
7599                 if (ret)
7600                         goto out;
7601         }
7602
7603         if (root_level == 0) {
7604                 ret = account_leaf_items(trans, root, root_eb);
7605                 goto out;
7606         }
7607
7608         path = btrfs_alloc_path();
7609         if (!path)
7610                 return -ENOMEM;
7611
7612         /*
7613          * Walk down the tree.  Missing extent blocks are filled in as
7614          * we go. Metadata is accounted every time we read a new
7615          * extent block.
7616          *
7617          * When we reach a leaf, we account for file extent items in it,
7618          * walk back up the tree (adjusting slot pointers as we go)
7619          * and restart the search process.
7620          */
7621         extent_buffer_get(root_eb); /* For path */
7622         path->nodes[root_level] = root_eb;
7623         path->slots[root_level] = 0;
7624         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
7625 walk_down:
7626         level = root_level;
7627         while (level >= 0) {
7628                 if (path->nodes[level] == NULL) {
7629                         int child_bsize = root->nodesize;
7630                         int parent_slot;
7631                         u64 child_gen;
7632                         u64 child_bytenr;
7633
7634                         /* We need to get child blockptr/gen from
7635                          * parent before we can read it. */
7636                         eb = path->nodes[level + 1];
7637                         parent_slot = path->slots[level + 1];
7638                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
7639                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
7640
7641                         eb = read_tree_block(root, child_bytenr, child_bsize,
7642                                              child_gen);
7643                         if (!eb || !extent_buffer_uptodate(eb)) {
7644                                 ret = -EIO;
7645                                 goto out;
7646                         }
7647
7648                         path->nodes[level] = eb;
7649                         path->slots[level] = 0;
7650
7651                         btrfs_tree_read_lock(eb);
7652                         btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
7653                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
7654
7655                         ret = btrfs_qgroup_record_ref(trans, root->fs_info,
7656                                                 root->objectid,
7657                                                 child_bytenr,
7658                                                 child_bsize,
7659                                                 BTRFS_QGROUP_OPER_SUB_SUBTREE,
7660                                                 0);
7661                         if (ret)
7662                                 goto out;
7663
7664                 }
7665
7666                 if (level == 0) {
7667                         ret = account_leaf_items(trans, root, path->nodes[level]);
7668                         if (ret)
7669                                 goto out;
7670
7671                         /* Nonzero return here means we completed our search */
7672                         ret = adjust_slots_upwards(root, path, root_level);
7673                         if (ret)
7674                                 break;
7675
7676                         /* Restart search with new slots */
7677                         goto walk_down;
7678                 }
7679
7680                 level--;
7681         }
7682
7683         ret = 0;
7684 out:
7685         btrfs_free_path(path);
7686
7687         return ret;
7688 }
7689
7690 /*
7691  * helper to process tree block while walking down the tree.
7692  *
7693  * when wc->stage == UPDATE_BACKREF, this function updates
7694  * back refs for pointers in the block.
7695  *
7696  * NOTE: return value 1 means we should stop walking down.
7697  */
7698 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7699                                    struct btrfs_root *root,
7700                                    struct btrfs_path *path,
7701                                    struct walk_control *wc, int lookup_info)
7702 {
7703         int level = wc->level;
7704         struct extent_buffer *eb = path->nodes[level];
7705         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7706         int ret;
7707
7708         if (wc->stage == UPDATE_BACKREF &&
7709             btrfs_header_owner(eb) != root->root_key.objectid)
7710                 return 1;
7711
7712         /*
7713          * when reference count of tree block is 1, it won't increase
7714          * again. once full backref flag is set, we never clear it.
7715          */
7716         if (lookup_info &&
7717             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7718              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7719                 BUG_ON(!path->locks[level]);
7720                 ret = btrfs_lookup_extent_info(trans, root,
7721                                                eb->start, level, 1,
7722                                                &wc->refs[level],
7723                                                &wc->flags[level]);
7724                 BUG_ON(ret == -ENOMEM);
7725                 if (ret)
7726                         return ret;
7727                 BUG_ON(wc->refs[level] == 0);
7728         }
7729
7730         if (wc->stage == DROP_REFERENCE) {
7731                 if (wc->refs[level] > 1)
7732                         return 1;
7733
7734                 if (path->locks[level] && !wc->keep_locks) {
7735                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7736                         path->locks[level] = 0;
7737                 }
7738                 return 0;
7739         }
7740
7741         /* wc->stage == UPDATE_BACKREF */
7742         if (!(wc->flags[level] & flag)) {
7743                 BUG_ON(!path->locks[level]);
7744                 ret = btrfs_inc_ref(trans, root, eb, 1);
7745                 BUG_ON(ret); /* -ENOMEM */
7746                 ret = btrfs_dec_ref(trans, root, eb, 0);
7747                 BUG_ON(ret); /* -ENOMEM */
7748                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7749                                                   eb->len, flag,
7750                                                   btrfs_header_level(eb), 0);
7751                 BUG_ON(ret); /* -ENOMEM */
7752                 wc->flags[level] |= flag;
7753         }
7754
7755         /*
7756          * the block is shared by multiple trees, so it's not good to
7757          * keep the tree lock
7758          */
7759         if (path->locks[level] && level > 0) {
7760                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7761                 path->locks[level] = 0;
7762         }
7763         return 0;
7764 }
7765
7766 /*
7767  * helper to process tree block pointer.
7768  *
7769  * when wc->stage == DROP_REFERENCE, this function checks
7770  * reference count of the block pointed to. if the block
7771  * is shared and we need update back refs for the subtree
7772  * rooted at the block, this function changes wc->stage to
7773  * UPDATE_BACKREF. if the block is shared and there is no
7774  * need to update back, this function drops the reference
7775  * to the block.
7776  *
7777  * NOTE: return value 1 means we should stop walking down.
7778  */
7779 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
7780                                  struct btrfs_root *root,
7781                                  struct btrfs_path *path,
7782                                  struct walk_control *wc, int *lookup_info)
7783 {
7784         u64 bytenr;
7785         u64 generation;
7786         u64 parent;
7787         u32 blocksize;
7788         struct btrfs_key key;
7789         struct extent_buffer *next;
7790         int level = wc->level;
7791         int reada = 0;
7792         int ret = 0;
7793         bool need_account = false;
7794
7795         generation = btrfs_node_ptr_generation(path->nodes[level],
7796                                                path->slots[level]);
7797         /*
7798          * if the lower level block was created before the snapshot
7799          * was created, we know there is no need to update back refs
7800          * for the subtree
7801          */
7802         if (wc->stage == UPDATE_BACKREF &&
7803             generation <= root->root_key.offset) {
7804                 *lookup_info = 1;
7805                 return 1;
7806         }
7807
7808         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
7809         blocksize = btrfs_level_size(root, level - 1);
7810
7811         next = btrfs_find_tree_block(root, bytenr, blocksize);
7812         if (!next) {
7813                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
7814                 if (!next)
7815                         return -ENOMEM;
7816                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
7817                                                level - 1);
7818                 reada = 1;
7819         }
7820         btrfs_tree_lock(next);
7821         btrfs_set_lock_blocking(next);
7822
7823         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
7824                                        &wc->refs[level - 1],
7825                                        &wc->flags[level - 1]);
7826         if (ret < 0) {
7827                 btrfs_tree_unlock(next);
7828                 return ret;
7829         }
7830
7831         if (unlikely(wc->refs[level - 1] == 0)) {
7832                 btrfs_err(root->fs_info, "Missing references.");
7833                 BUG();
7834         }
7835         *lookup_info = 0;
7836
7837         if (wc->stage == DROP_REFERENCE) {
7838                 if (wc->refs[level - 1] > 1) {
7839                         need_account = true;
7840                         if (level == 1 &&
7841                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7842                                 goto skip;
7843
7844                         if (!wc->update_ref ||
7845                             generation <= root->root_key.offset)
7846                                 goto skip;
7847
7848                         btrfs_node_key_to_cpu(path->nodes[level], &key,
7849                                               path->slots[level]);
7850                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
7851                         if (ret < 0)
7852                                 goto skip;
7853
7854                         wc->stage = UPDATE_BACKREF;
7855                         wc->shared_level = level - 1;
7856                 }
7857         } else {
7858                 if (level == 1 &&
7859                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7860                         goto skip;
7861         }
7862
7863         if (!btrfs_buffer_uptodate(next, generation, 0)) {
7864                 btrfs_tree_unlock(next);
7865                 free_extent_buffer(next);
7866                 next = NULL;
7867                 *lookup_info = 1;
7868         }
7869
7870         if (!next) {
7871                 if (reada && level == 1)
7872                         reada_walk_down(trans, root, wc, path);
7873                 next = read_tree_block(root, bytenr, blocksize, generation);
7874                 if (!next || !extent_buffer_uptodate(next)) {
7875                         free_extent_buffer(next);
7876                         return -EIO;
7877                 }
7878                 btrfs_tree_lock(next);
7879                 btrfs_set_lock_blocking(next);
7880         }
7881
7882         level--;
7883         BUG_ON(level != btrfs_header_level(next));
7884         path->nodes[level] = next;
7885         path->slots[level] = 0;
7886         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7887         wc->level = level;
7888         if (wc->level == 1)
7889                 wc->reada_slot = 0;
7890         return 0;
7891 skip:
7892         wc->refs[level - 1] = 0;
7893         wc->flags[level - 1] = 0;
7894         if (wc->stage == DROP_REFERENCE) {
7895                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
7896                         parent = path->nodes[level]->start;
7897                 } else {
7898                         BUG_ON(root->root_key.objectid !=
7899                                btrfs_header_owner(path->nodes[level]));
7900                         parent = 0;
7901                 }
7902
7903                 if (need_account) {
7904                         ret = account_shared_subtree(trans, root, next,
7905                                                      generation, level - 1);
7906                         if (ret) {
7907                                 printk_ratelimited(KERN_ERR "BTRFS: %s Error "
7908                                         "%d accounting shared subtree. Quota "
7909                                         "is out of sync, rescan required.\n",
7910                                         root->fs_info->sb->s_id, ret);
7911                         }
7912                 }
7913                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
7914                                 root->root_key.objectid, level - 1, 0, 0);
7915                 BUG_ON(ret); /* -ENOMEM */
7916         }
7917         btrfs_tree_unlock(next);
7918         free_extent_buffer(next);
7919         *lookup_info = 1;
7920         return 1;
7921 }
7922
7923 /*
7924  * helper to process tree block while walking up the tree.
7925  *
7926  * when wc->stage == DROP_REFERENCE, this function drops
7927  * reference count on the block.
7928  *
7929  * when wc->stage == UPDATE_BACKREF, this function changes
7930  * wc->stage back to DROP_REFERENCE if we changed wc->stage
7931  * to UPDATE_BACKREF previously while processing the block.
7932  *
7933  * NOTE: return value 1 means we should stop walking up.
7934  */
7935 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
7936                                  struct btrfs_root *root,
7937                                  struct btrfs_path *path,
7938                                  struct walk_control *wc)
7939 {
7940         int ret;
7941         int level = wc->level;
7942         struct extent_buffer *eb = path->nodes[level];
7943         u64 parent = 0;
7944
7945         if (wc->stage == UPDATE_BACKREF) {
7946                 BUG_ON(wc->shared_level < level);
7947                 if (level < wc->shared_level)
7948                         goto out;
7949
7950                 ret = find_next_key(path, level + 1, &wc->update_progress);
7951                 if (ret > 0)
7952                         wc->update_ref = 0;
7953
7954                 wc->stage = DROP_REFERENCE;
7955                 wc->shared_level = -1;
7956                 path->slots[level] = 0;
7957
7958                 /*
7959                  * check reference count again if the block isn't locked.
7960                  * we should start walking down the tree again if reference
7961                  * count is one.
7962                  */
7963                 if (!path->locks[level]) {
7964                         BUG_ON(level == 0);
7965                         btrfs_tree_lock(eb);
7966                         btrfs_set_lock_blocking(eb);
7967                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7968
7969                         ret = btrfs_lookup_extent_info(trans, root,
7970                                                        eb->start, level, 1,
7971                                                        &wc->refs[level],
7972                                                        &wc->flags[level]);
7973                         if (ret < 0) {
7974                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7975                                 path->locks[level] = 0;
7976                                 return ret;
7977                         }
7978                         BUG_ON(wc->refs[level] == 0);
7979                         if (wc->refs[level] == 1) {
7980                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7981                                 path->locks[level] = 0;
7982                                 return 1;
7983                         }
7984                 }
7985         }
7986
7987         /* wc->stage == DROP_REFERENCE */
7988         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7989
7990         if (wc->refs[level] == 1) {
7991                 if (level == 0) {
7992                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7993                                 ret = btrfs_dec_ref(trans, root, eb, 1);
7994                         else
7995                                 ret = btrfs_dec_ref(trans, root, eb, 0);
7996                         BUG_ON(ret); /* -ENOMEM */
7997                         ret = account_leaf_items(trans, root, eb);
7998                         if (ret) {
7999                                 printk_ratelimited(KERN_ERR "BTRFS: %s Error "
8000                                         "%d accounting leaf items. Quota "
8001                                         "is out of sync, rescan required.\n",
8002                                         root->fs_info->sb->s_id, ret);
8003                         }
8004                 }
8005                 /* make block locked assertion in clean_tree_block happy */
8006                 if (!path->locks[level] &&
8007                     btrfs_header_generation(eb) == trans->transid) {
8008                         btrfs_tree_lock(eb);
8009                         btrfs_set_lock_blocking(eb);
8010                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8011                 }
8012                 clean_tree_block(trans, root, eb);
8013         }
8014
8015         if (eb == root->node) {
8016                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8017                         parent = eb->start;
8018                 else
8019                         BUG_ON(root->root_key.objectid !=
8020                                btrfs_header_owner(eb));
8021         } else {
8022                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8023                         parent = path->nodes[level + 1]->start;
8024                 else
8025                         BUG_ON(root->root_key.objectid !=
8026                                btrfs_header_owner(path->nodes[level + 1]));
8027         }
8028
8029         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8030 out:
8031         wc->refs[level] = 0;
8032         wc->flags[level] = 0;
8033         return 0;
8034 }
8035
8036 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8037                                    struct btrfs_root *root,
8038                                    struct btrfs_path *path,
8039                                    struct walk_control *wc)
8040 {
8041         int level = wc->level;
8042         int lookup_info = 1;
8043         int ret;
8044
8045         while (level >= 0) {
8046                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8047                 if (ret > 0)
8048                         break;
8049
8050                 if (level == 0)
8051                         break;
8052
8053                 if (path->slots[level] >=
8054                     btrfs_header_nritems(path->nodes[level]))
8055                         break;
8056
8057                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8058                 if (ret > 0) {
8059                         path->slots[level]++;
8060                         continue;
8061                 } else if (ret < 0)
8062                         return ret;
8063                 level = wc->level;
8064         }
8065         return 0;
8066 }
8067
8068 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8069                                  struct btrfs_root *root,
8070                                  struct btrfs_path *path,
8071                                  struct walk_control *wc, int max_level)
8072 {
8073         int level = wc->level;
8074         int ret;
8075
8076         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8077         while (level < max_level && path->nodes[level]) {
8078                 wc->level = level;
8079                 if (path->slots[level] + 1 <
8080                     btrfs_header_nritems(path->nodes[level])) {
8081                         path->slots[level]++;
8082                         return 0;
8083                 } else {
8084                         ret = walk_up_proc(trans, root, path, wc);
8085                         if (ret > 0)
8086                                 return 0;
8087
8088                         if (path->locks[level]) {
8089                                 btrfs_tree_unlock_rw(path->nodes[level],
8090                                                      path->locks[level]);
8091                                 path->locks[level] = 0;
8092                         }
8093                         free_extent_buffer(path->nodes[level]);
8094                         path->nodes[level] = NULL;
8095                         level++;
8096                 }
8097         }
8098         return 1;
8099 }
8100
8101 /*
8102  * drop a subvolume tree.
8103  *
8104  * this function traverses the tree freeing any blocks that only
8105  * referenced by the tree.
8106  *
8107  * when a shared tree block is found. this function decreases its
8108  * reference count by one. if update_ref is true, this function
8109  * also make sure backrefs for the shared block and all lower level
8110  * blocks are properly updated.
8111  *
8112  * If called with for_reloc == 0, may exit early with -EAGAIN
8113  */
8114 int btrfs_drop_snapshot(struct btrfs_root *root,
8115                          struct btrfs_block_rsv *block_rsv, int update_ref,
8116                          int for_reloc)
8117 {
8118         struct btrfs_path *path;
8119         struct btrfs_trans_handle *trans;
8120         struct btrfs_root *tree_root = root->fs_info->tree_root;
8121         struct btrfs_root_item *root_item = &root->root_item;
8122         struct walk_control *wc;
8123         struct btrfs_key key;
8124         int err = 0;
8125         int ret;
8126         int level;
8127         bool root_dropped = false;
8128
8129         btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
8130
8131         path = btrfs_alloc_path();
8132         if (!path) {
8133                 err = -ENOMEM;
8134                 goto out;
8135         }
8136
8137         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8138         if (!wc) {
8139                 btrfs_free_path(path);
8140                 err = -ENOMEM;
8141                 goto out;
8142         }
8143
8144         trans = btrfs_start_transaction(tree_root, 0);
8145         if (IS_ERR(trans)) {
8146                 err = PTR_ERR(trans);
8147                 goto out_free;
8148         }
8149
8150         if (block_rsv)
8151                 trans->block_rsv = block_rsv;
8152
8153         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8154                 level = btrfs_header_level(root->node);
8155                 path->nodes[level] = btrfs_lock_root_node(root);
8156                 btrfs_set_lock_blocking(path->nodes[level]);
8157                 path->slots[level] = 0;
8158                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8159                 memset(&wc->update_progress, 0,
8160                        sizeof(wc->update_progress));
8161         } else {
8162                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8163                 memcpy(&wc->update_progress, &key,
8164                        sizeof(wc->update_progress));
8165
8166                 level = root_item->drop_level;
8167                 BUG_ON(level == 0);
8168                 path->lowest_level = level;
8169                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8170                 path->lowest_level = 0;
8171                 if (ret < 0) {
8172                         err = ret;
8173                         goto out_end_trans;
8174                 }
8175                 WARN_ON(ret > 0);
8176
8177                 /*
8178                  * unlock our path, this is safe because only this
8179                  * function is allowed to delete this snapshot
8180                  */
8181                 btrfs_unlock_up_safe(path, 0);
8182
8183                 level = btrfs_header_level(root->node);
8184                 while (1) {
8185                         btrfs_tree_lock(path->nodes[level]);
8186                         btrfs_set_lock_blocking(path->nodes[level]);
8187                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8188
8189                         ret = btrfs_lookup_extent_info(trans, root,
8190                                                 path->nodes[level]->start,
8191                                                 level, 1, &wc->refs[level],
8192                                                 &wc->flags[level]);
8193                         if (ret < 0) {
8194                                 err = ret;
8195                                 goto out_end_trans;
8196                         }
8197                         BUG_ON(wc->refs[level] == 0);
8198
8199                         if (level == root_item->drop_level)
8200                                 break;
8201
8202                         btrfs_tree_unlock(path->nodes[level]);
8203                         path->locks[level] = 0;
8204                         WARN_ON(wc->refs[level] != 1);
8205                         level--;
8206                 }
8207         }
8208
8209         wc->level = level;
8210         wc->shared_level = -1;
8211         wc->stage = DROP_REFERENCE;
8212         wc->update_ref = update_ref;
8213         wc->keep_locks = 0;
8214         wc->for_reloc = for_reloc;
8215         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8216
8217         while (1) {
8218
8219                 ret = walk_down_tree(trans, root, path, wc);
8220                 if (ret < 0) {
8221                         err = ret;
8222                         break;
8223                 }
8224
8225                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
8226                 if (ret < 0) {
8227                         err = ret;
8228                         break;
8229                 }
8230
8231                 if (ret > 0) {
8232                         BUG_ON(wc->stage != DROP_REFERENCE);
8233                         break;
8234                 }
8235
8236                 if (wc->stage == DROP_REFERENCE) {
8237                         level = wc->level;
8238                         btrfs_node_key(path->nodes[level],
8239                                        &root_item->drop_progress,
8240                                        path->slots[level]);
8241                         root_item->drop_level = level;
8242                 }
8243
8244                 BUG_ON(wc->level == 0);
8245                 if (btrfs_should_end_transaction(trans, tree_root) ||
8246                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
8247                         ret = btrfs_update_root(trans, tree_root,
8248                                                 &root->root_key,
8249                                                 root_item);
8250                         if (ret) {
8251                                 btrfs_abort_transaction(trans, tree_root, ret);
8252                                 err = ret;
8253                                 goto out_end_trans;
8254                         }
8255
8256                         /*
8257                          * Qgroup update accounting is run from
8258                          * delayed ref handling. This usually works
8259                          * out because delayed refs are normally the
8260                          * only way qgroup updates are added. However,
8261                          * we may have added updates during our tree
8262                          * walk so run qgroups here to make sure we
8263                          * don't lose any updates.
8264                          */
8265                         ret = btrfs_delayed_qgroup_accounting(trans,
8266                                                               root->fs_info);
8267                         if (ret)
8268                                 printk_ratelimited(KERN_ERR "BTRFS: Failure %d "
8269                                                    "running qgroup updates "
8270                                                    "during snapshot delete. "
8271                                                    "Quota is out of sync, "
8272                                                    "rescan required.\n", ret);
8273
8274                         btrfs_end_transaction_throttle(trans, tree_root);
8275                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
8276                                 pr_debug("BTRFS: drop snapshot early exit\n");
8277                                 err = -EAGAIN;
8278                                 goto out_free;
8279                         }
8280
8281                         trans = btrfs_start_transaction(tree_root, 0);
8282                         if (IS_ERR(trans)) {
8283                                 err = PTR_ERR(trans);
8284                                 goto out_free;
8285                         }
8286                         if (block_rsv)
8287                                 trans->block_rsv = block_rsv;
8288                 }
8289         }
8290         btrfs_release_path(path);
8291         if (err)
8292                 goto out_end_trans;
8293
8294         ret = btrfs_del_root(trans, tree_root, &root->root_key);
8295         if (ret) {
8296                 btrfs_abort_transaction(trans, tree_root, ret);
8297                 goto out_end_trans;
8298         }
8299
8300         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
8301                 ret = btrfs_find_root(tree_root, &root->root_key, path,
8302                                       NULL, NULL);
8303                 if (ret < 0) {
8304                         btrfs_abort_transaction(trans, tree_root, ret);
8305                         err = ret;
8306                         goto out_end_trans;
8307                 } else if (ret > 0) {
8308                         /* if we fail to delete the orphan item this time
8309                          * around, it'll get picked up the next time.
8310                          *
8311                          * The most common failure here is just -ENOENT.
8312                          */
8313                         btrfs_del_orphan_item(trans, tree_root,
8314                                               root->root_key.objectid);
8315                 }
8316         }
8317
8318         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
8319                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
8320         } else {
8321                 free_extent_buffer(root->node);
8322                 free_extent_buffer(root->commit_root);
8323                 btrfs_put_fs_root(root);
8324         }
8325         root_dropped = true;
8326 out_end_trans:
8327         ret = btrfs_delayed_qgroup_accounting(trans, tree_root->fs_info);
8328         if (ret)
8329                 printk_ratelimited(KERN_ERR "BTRFS: Failure %d "
8330                                    "running qgroup updates "
8331                                    "during snapshot delete. "
8332                                    "Quota is out of sync, "
8333                                    "rescan required.\n", ret);
8334
8335         btrfs_end_transaction_throttle(trans, tree_root);
8336 out_free:
8337         kfree(wc);
8338         btrfs_free_path(path);
8339 out:
8340         /*
8341          * So if we need to stop dropping the snapshot for whatever reason we
8342          * need to make sure to add it back to the dead root list so that we
8343          * keep trying to do the work later.  This also cleans up roots if we
8344          * don't have it in the radix (like when we recover after a power fail
8345          * or unmount) so we don't leak memory.
8346          */
8347         if (!for_reloc && root_dropped == false)
8348                 btrfs_add_dead_root(root);
8349         if (err && err != -EAGAIN)
8350                 btrfs_std_error(root->fs_info, err);
8351         return err;
8352 }
8353
8354 /*
8355  * drop subtree rooted at tree block 'node'.
8356  *
8357  * NOTE: this function will unlock and release tree block 'node'
8358  * only used by relocation code
8359  */
8360 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
8361                         struct btrfs_root *root,
8362                         struct extent_buffer *node,
8363                         struct extent_buffer *parent)
8364 {
8365         struct btrfs_path *path;
8366         struct walk_control *wc;
8367         int level;
8368         int parent_level;
8369         int ret = 0;
8370         int wret;
8371
8372         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
8373
8374         path = btrfs_alloc_path();
8375         if (!path)
8376                 return -ENOMEM;
8377
8378         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8379         if (!wc) {
8380                 btrfs_free_path(path);
8381                 return -ENOMEM;
8382         }
8383
8384         btrfs_assert_tree_locked(parent);
8385         parent_level = btrfs_header_level(parent);
8386         extent_buffer_get(parent);
8387         path->nodes[parent_level] = parent;
8388         path->slots[parent_level] = btrfs_header_nritems(parent);
8389
8390         btrfs_assert_tree_locked(node);
8391         level = btrfs_header_level(node);
8392         path->nodes[level] = node;
8393         path->slots[level] = 0;
8394         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8395
8396         wc->refs[parent_level] = 1;
8397         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8398         wc->level = level;
8399         wc->shared_level = -1;
8400         wc->stage = DROP_REFERENCE;
8401         wc->update_ref = 0;
8402         wc->keep_locks = 1;
8403         wc->for_reloc = 1;
8404         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8405
8406         while (1) {
8407                 wret = walk_down_tree(trans, root, path, wc);
8408                 if (wret < 0) {
8409                         ret = wret;
8410                         break;
8411                 }
8412
8413                 wret = walk_up_tree(trans, root, path, wc, parent_level);
8414                 if (wret < 0)
8415                         ret = wret;
8416                 if (wret != 0)
8417                         break;
8418         }
8419
8420         kfree(wc);
8421         btrfs_free_path(path);
8422         return ret;
8423 }
8424
8425 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
8426 {
8427         u64 num_devices;
8428         u64 stripped;
8429
8430         /*
8431          * if restripe for this chunk_type is on pick target profile and
8432          * return, otherwise do the usual balance
8433          */
8434         stripped = get_restripe_target(root->fs_info, flags);
8435         if (stripped)
8436                 return extended_to_chunk(stripped);
8437
8438         num_devices = root->fs_info->fs_devices->rw_devices;
8439
8440         stripped = BTRFS_BLOCK_GROUP_RAID0 |
8441                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
8442                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
8443
8444         if (num_devices == 1) {
8445                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8446                 stripped = flags & ~stripped;
8447
8448                 /* turn raid0 into single device chunks */
8449                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
8450                         return stripped;
8451
8452                 /* turn mirroring into duplication */
8453                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
8454                              BTRFS_BLOCK_GROUP_RAID10))
8455                         return stripped | BTRFS_BLOCK_GROUP_DUP;
8456         } else {
8457                 /* they already had raid on here, just return */
8458                 if (flags & stripped)
8459                         return flags;
8460
8461                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8462                 stripped = flags & ~stripped;
8463
8464                 /* switch duplicated blocks with raid1 */
8465                 if (flags & BTRFS_BLOCK_GROUP_DUP)
8466                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
8467
8468                 /* this is drive concat, leave it alone */
8469         }
8470
8471         return flags;
8472 }
8473
8474 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
8475 {
8476         struct btrfs_space_info *sinfo = cache->space_info;
8477         u64 num_bytes;
8478         u64 min_allocable_bytes;
8479         int ret = -ENOSPC;
8480
8481
8482         /*
8483          * We need some metadata space and system metadata space for
8484          * allocating chunks in some corner cases until we force to set
8485          * it to be readonly.
8486          */
8487         if ((sinfo->flags &
8488              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
8489             !force)
8490                 min_allocable_bytes = 1 * 1024 * 1024;
8491         else
8492                 min_allocable_bytes = 0;
8493
8494         spin_lock(&sinfo->lock);
8495         spin_lock(&cache->lock);
8496
8497         if (cache->ro) {
8498                 ret = 0;
8499                 goto out;
8500         }
8501
8502         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8503                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8504
8505         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
8506             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
8507             min_allocable_bytes <= sinfo->total_bytes) {
8508                 sinfo->bytes_readonly += num_bytes;
8509                 cache->ro = 1;
8510                 ret = 0;
8511         }
8512 out:
8513         spin_unlock(&cache->lock);
8514         spin_unlock(&sinfo->lock);
8515         return ret;
8516 }
8517
8518 int btrfs_set_block_group_ro(struct btrfs_root *root,
8519                              struct btrfs_block_group_cache *cache)
8520
8521 {
8522         struct btrfs_trans_handle *trans;
8523         u64 alloc_flags;
8524         int ret;
8525
8526         BUG_ON(cache->ro);
8527
8528         trans = btrfs_join_transaction(root);
8529         if (IS_ERR(trans))
8530                 return PTR_ERR(trans);
8531
8532         alloc_flags = update_block_group_flags(root, cache->flags);
8533         if (alloc_flags != cache->flags) {
8534                 ret = do_chunk_alloc(trans, root, alloc_flags,
8535                                      CHUNK_ALLOC_FORCE);
8536                 if (ret < 0)
8537                         goto out;
8538         }
8539
8540         ret = set_block_group_ro(cache, 0);
8541         if (!ret)
8542                 goto out;
8543         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
8544         ret = do_chunk_alloc(trans, root, alloc_flags,
8545                              CHUNK_ALLOC_FORCE);
8546         if (ret < 0)
8547                 goto out;
8548         ret = set_block_group_ro(cache, 0);
8549 out:
8550         btrfs_end_transaction(trans, root);
8551         return ret;
8552 }
8553
8554 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
8555                             struct btrfs_root *root, u64 type)
8556 {
8557         u64 alloc_flags = get_alloc_profile(root, type);
8558         return do_chunk_alloc(trans, root, alloc_flags,
8559                               CHUNK_ALLOC_FORCE);
8560 }
8561
8562 /*
8563  * helper to account the unused space of all the readonly block group in the
8564  * list. takes mirrors into account.
8565  */
8566 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
8567 {
8568         struct btrfs_block_group_cache *block_group;
8569         u64 free_bytes = 0;
8570         int factor;
8571
8572         list_for_each_entry(block_group, groups_list, list) {
8573                 spin_lock(&block_group->lock);
8574
8575                 if (!block_group->ro) {
8576                         spin_unlock(&block_group->lock);
8577                         continue;
8578                 }
8579
8580                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
8581                                           BTRFS_BLOCK_GROUP_RAID10 |
8582                                           BTRFS_BLOCK_GROUP_DUP))
8583                         factor = 2;
8584                 else
8585                         factor = 1;
8586
8587                 free_bytes += (block_group->key.offset -
8588                                btrfs_block_group_used(&block_group->item)) *
8589                                factor;
8590
8591                 spin_unlock(&block_group->lock);
8592         }
8593
8594         return free_bytes;
8595 }
8596
8597 /*
8598  * helper to account the unused space of all the readonly block group in the
8599  * space_info. takes mirrors into account.
8600  */
8601 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
8602 {
8603         int i;
8604         u64 free_bytes = 0;
8605
8606         spin_lock(&sinfo->lock);
8607
8608         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
8609                 if (!list_empty(&sinfo->block_groups[i]))
8610                         free_bytes += __btrfs_get_ro_block_group_free_space(
8611                                                 &sinfo->block_groups[i]);
8612
8613         spin_unlock(&sinfo->lock);
8614
8615         return free_bytes;
8616 }
8617
8618 void btrfs_set_block_group_rw(struct btrfs_root *root,
8619                               struct btrfs_block_group_cache *cache)
8620 {
8621         struct btrfs_space_info *sinfo = cache->space_info;
8622         u64 num_bytes;
8623
8624         BUG_ON(!cache->ro);
8625
8626         spin_lock(&sinfo->lock);
8627         spin_lock(&cache->lock);
8628         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8629                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8630         sinfo->bytes_readonly -= num_bytes;
8631         cache->ro = 0;
8632         spin_unlock(&cache->lock);
8633         spin_unlock(&sinfo->lock);
8634 }
8635
8636 /*
8637  * checks to see if its even possible to relocate this block group.
8638  *
8639  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
8640  * ok to go ahead and try.
8641  */
8642 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
8643 {
8644         struct btrfs_block_group_cache *block_group;
8645         struct btrfs_space_info *space_info;
8646         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
8647         struct btrfs_device *device;
8648         struct btrfs_trans_handle *trans;
8649         u64 min_free;
8650         u64 dev_min = 1;
8651         u64 dev_nr = 0;
8652         u64 target;
8653         int index;
8654         int full = 0;
8655         int ret = 0;
8656
8657         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
8658
8659         /* odd, couldn't find the block group, leave it alone */
8660         if (!block_group)
8661                 return -1;
8662
8663         min_free = btrfs_block_group_used(&block_group->item);
8664
8665         /* no bytes used, we're good */
8666         if (!min_free)
8667                 goto out;
8668
8669         space_info = block_group->space_info;
8670         spin_lock(&space_info->lock);
8671
8672         full = space_info->full;
8673
8674         /*
8675          * if this is the last block group we have in this space, we can't
8676          * relocate it unless we're able to allocate a new chunk below.
8677          *
8678          * Otherwise, we need to make sure we have room in the space to handle
8679          * all of the extents from this block group.  If we can, we're good
8680          */
8681         if ((space_info->total_bytes != block_group->key.offset) &&
8682             (space_info->bytes_used + space_info->bytes_reserved +
8683              space_info->bytes_pinned + space_info->bytes_readonly +
8684              min_free < space_info->total_bytes)) {
8685                 spin_unlock(&space_info->lock);
8686                 goto out;
8687         }
8688         spin_unlock(&space_info->lock);
8689
8690         /*
8691          * ok we don't have enough space, but maybe we have free space on our
8692          * devices to allocate new chunks for relocation, so loop through our
8693          * alloc devices and guess if we have enough space.  if this block
8694          * group is going to be restriped, run checks against the target
8695          * profile instead of the current one.
8696          */
8697         ret = -1;
8698
8699         /*
8700          * index:
8701          *      0: raid10
8702          *      1: raid1
8703          *      2: dup
8704          *      3: raid0
8705          *      4: single
8706          */
8707         target = get_restripe_target(root->fs_info, block_group->flags);
8708         if (target) {
8709                 index = __get_raid_index(extended_to_chunk(target));
8710         } else {
8711                 /*
8712                  * this is just a balance, so if we were marked as full
8713                  * we know there is no space for a new chunk
8714                  */
8715                 if (full)
8716                         goto out;
8717
8718                 index = get_block_group_index(block_group);
8719         }
8720
8721         if (index == BTRFS_RAID_RAID10) {
8722                 dev_min = 4;
8723                 /* Divide by 2 */
8724                 min_free >>= 1;
8725         } else if (index == BTRFS_RAID_RAID1) {
8726                 dev_min = 2;
8727         } else if (index == BTRFS_RAID_DUP) {
8728                 /* Multiply by 2 */
8729                 min_free <<= 1;
8730         } else if (index == BTRFS_RAID_RAID0) {
8731                 dev_min = fs_devices->rw_devices;
8732                 do_div(min_free, dev_min);
8733         }
8734
8735         /* We need to do this so that we can look at pending chunks */
8736         trans = btrfs_join_transaction(root);
8737         if (IS_ERR(trans)) {
8738                 ret = PTR_ERR(trans);
8739                 goto out;
8740         }
8741
8742         mutex_lock(&root->fs_info->chunk_mutex);
8743         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8744                 u64 dev_offset;
8745
8746                 /*
8747                  * check to make sure we can actually find a chunk with enough
8748                  * space to fit our block group in.
8749                  */
8750                 if (device->total_bytes > device->bytes_used + min_free &&
8751                     !device->is_tgtdev_for_dev_replace) {
8752                         ret = find_free_dev_extent(trans, device, min_free,
8753                                                    &dev_offset, NULL);
8754                         if (!ret)
8755                                 dev_nr++;
8756
8757                         if (dev_nr >= dev_min)
8758                                 break;
8759
8760                         ret = -1;
8761                 }
8762         }
8763         mutex_unlock(&root->fs_info->chunk_mutex);
8764         btrfs_end_transaction(trans, root);
8765 out:
8766         btrfs_put_block_group(block_group);
8767         return ret;
8768 }
8769
8770 static int find_first_block_group(struct btrfs_root *root,
8771                 struct btrfs_path *path, struct btrfs_key *key)
8772 {
8773         int ret = 0;
8774         struct btrfs_key found_key;
8775         struct extent_buffer *leaf;
8776         int slot;
8777
8778         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
8779         if (ret < 0)
8780                 goto out;
8781
8782         while (1) {
8783                 slot = path->slots[0];
8784                 leaf = path->nodes[0];
8785                 if (slot >= btrfs_header_nritems(leaf)) {
8786                         ret = btrfs_next_leaf(root, path);
8787                         if (ret == 0)
8788                                 continue;
8789                         if (ret < 0)
8790                                 goto out;
8791                         break;
8792                 }
8793                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
8794
8795                 if (found_key.objectid >= key->objectid &&
8796                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
8797                         ret = 0;
8798                         goto out;
8799                 }
8800                 path->slots[0]++;
8801         }
8802 out:
8803         return ret;
8804 }
8805
8806 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
8807 {
8808         struct btrfs_block_group_cache *block_group;
8809         u64 last = 0;
8810
8811         while (1) {
8812                 struct inode *inode;
8813
8814                 block_group = btrfs_lookup_first_block_group(info, last);
8815                 while (block_group) {
8816                         spin_lock(&block_group->lock);
8817                         if (block_group->iref)
8818                                 break;
8819                         spin_unlock(&block_group->lock);
8820                         block_group = next_block_group(info->tree_root,
8821                                                        block_group);
8822                 }
8823                 if (!block_group) {
8824                         if (last == 0)
8825                                 break;
8826                         last = 0;
8827                         continue;
8828                 }
8829
8830                 inode = block_group->inode;
8831                 block_group->iref = 0;
8832                 block_group->inode = NULL;
8833                 spin_unlock(&block_group->lock);
8834                 iput(inode);
8835                 last = block_group->key.objectid + block_group->key.offset;
8836                 btrfs_put_block_group(block_group);
8837         }
8838 }
8839
8840 int btrfs_free_block_groups(struct btrfs_fs_info *info)
8841 {
8842         struct btrfs_block_group_cache *block_group;
8843         struct btrfs_space_info *space_info;
8844         struct btrfs_caching_control *caching_ctl;
8845         struct rb_node *n;
8846
8847         down_write(&info->commit_root_sem);
8848         while (!list_empty(&info->caching_block_groups)) {
8849                 caching_ctl = list_entry(info->caching_block_groups.next,
8850                                          struct btrfs_caching_control, list);
8851                 list_del(&caching_ctl->list);
8852                 put_caching_control(caching_ctl);
8853         }
8854         up_write(&info->commit_root_sem);
8855
8856         spin_lock(&info->block_group_cache_lock);
8857         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
8858                 block_group = rb_entry(n, struct btrfs_block_group_cache,
8859                                        cache_node);
8860                 rb_erase(&block_group->cache_node,
8861                          &info->block_group_cache_tree);
8862                 spin_unlock(&info->block_group_cache_lock);
8863
8864                 down_write(&block_group->space_info->groups_sem);
8865                 list_del(&block_group->list);
8866                 up_write(&block_group->space_info->groups_sem);
8867
8868                 if (block_group->cached == BTRFS_CACHE_STARTED)
8869                         wait_block_group_cache_done(block_group);
8870
8871                 /*
8872                  * We haven't cached this block group, which means we could
8873                  * possibly have excluded extents on this block group.
8874                  */
8875                 if (block_group->cached == BTRFS_CACHE_NO ||
8876                     block_group->cached == BTRFS_CACHE_ERROR)
8877                         free_excluded_extents(info->extent_root, block_group);
8878
8879                 btrfs_remove_free_space_cache(block_group);
8880                 btrfs_put_block_group(block_group);
8881
8882                 spin_lock(&info->block_group_cache_lock);
8883         }
8884         spin_unlock(&info->block_group_cache_lock);
8885
8886         /* now that all the block groups are freed, go through and
8887          * free all the space_info structs.  This is only called during
8888          * the final stages of unmount, and so we know nobody is
8889          * using them.  We call synchronize_rcu() once before we start,
8890          * just to be on the safe side.
8891          */
8892         synchronize_rcu();
8893
8894         release_global_block_rsv(info);
8895
8896         while (!list_empty(&info->space_info)) {
8897                 int i;
8898
8899                 space_info = list_entry(info->space_info.next,
8900                                         struct btrfs_space_info,
8901                                         list);
8902                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
8903                         if (WARN_ON(space_info->bytes_pinned > 0 ||
8904                             space_info->bytes_reserved > 0 ||
8905                             space_info->bytes_may_use > 0)) {
8906                                 dump_space_info(space_info, 0, 0);
8907                         }
8908                 }
8909                 list_del(&space_info->list);
8910                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
8911                         struct kobject *kobj;
8912                         kobj = space_info->block_group_kobjs[i];
8913                         space_info->block_group_kobjs[i] = NULL;
8914                         if (kobj) {
8915                                 kobject_del(kobj);
8916                                 kobject_put(kobj);
8917                         }
8918                 }
8919                 kobject_del(&space_info->kobj);
8920                 kobject_put(&space_info->kobj);
8921         }
8922         return 0;
8923 }
8924
8925 static void __link_block_group(struct btrfs_space_info *space_info,
8926                                struct btrfs_block_group_cache *cache)
8927 {
8928         int index = get_block_group_index(cache);
8929         bool first = false;
8930
8931         down_write(&space_info->groups_sem);
8932         if (list_empty(&space_info->block_groups[index]))
8933                 first = true;
8934         list_add_tail(&cache->list, &space_info->block_groups[index]);
8935         up_write(&space_info->groups_sem);
8936
8937         if (first) {
8938                 struct raid_kobject *rkobj;
8939                 int ret;
8940
8941                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
8942                 if (!rkobj)
8943                         goto out_err;
8944                 rkobj->raid_type = index;
8945                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
8946                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
8947                                   "%s", get_raid_name(index));
8948                 if (ret) {
8949                         kobject_put(&rkobj->kobj);
8950                         goto out_err;
8951                 }
8952                 space_info->block_group_kobjs[index] = &rkobj->kobj;
8953         }
8954
8955         return;
8956 out_err:
8957         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
8958 }
8959
8960 static struct btrfs_block_group_cache *
8961 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
8962 {
8963         struct btrfs_block_group_cache *cache;
8964
8965         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8966         if (!cache)
8967                 return NULL;
8968
8969         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8970                                         GFP_NOFS);
8971         if (!cache->free_space_ctl) {
8972                 kfree(cache);
8973                 return NULL;
8974         }
8975
8976         cache->key.objectid = start;
8977         cache->key.offset = size;
8978         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8979
8980         cache->sectorsize = root->sectorsize;
8981         cache->fs_info = root->fs_info;
8982         cache->full_stripe_len = btrfs_full_stripe_len(root,
8983                                                &root->fs_info->mapping_tree,
8984                                                start);
8985         atomic_set(&cache->count, 1);
8986         spin_lock_init(&cache->lock);
8987         init_rwsem(&cache->data_rwsem);
8988         INIT_LIST_HEAD(&cache->list);
8989         INIT_LIST_HEAD(&cache->cluster_list);
8990         INIT_LIST_HEAD(&cache->new_bg_list);
8991         btrfs_init_free_space_ctl(cache);
8992
8993         return cache;
8994 }
8995
8996 int btrfs_read_block_groups(struct btrfs_root *root)
8997 {
8998         struct btrfs_path *path;
8999         int ret;
9000         struct btrfs_block_group_cache *cache;
9001         struct btrfs_fs_info *info = root->fs_info;
9002         struct btrfs_space_info *space_info;
9003         struct btrfs_key key;
9004         struct btrfs_key found_key;
9005         struct extent_buffer *leaf;
9006         int need_clear = 0;
9007         u64 cache_gen;
9008
9009         root = info->extent_root;
9010         key.objectid = 0;
9011         key.offset = 0;
9012         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
9013         path = btrfs_alloc_path();
9014         if (!path)
9015                 return -ENOMEM;
9016         path->reada = 1;
9017
9018         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
9019         if (btrfs_test_opt(root, SPACE_CACHE) &&
9020             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
9021                 need_clear = 1;
9022         if (btrfs_test_opt(root, CLEAR_CACHE))
9023                 need_clear = 1;
9024
9025         while (1) {
9026                 ret = find_first_block_group(root, path, &key);
9027                 if (ret > 0)
9028                         break;
9029                 if (ret != 0)
9030                         goto error;
9031
9032                 leaf = path->nodes[0];
9033                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9034
9035                 cache = btrfs_create_block_group_cache(root, found_key.objectid,
9036                                                        found_key.offset);
9037                 if (!cache) {
9038                         ret = -ENOMEM;
9039                         goto error;
9040                 }
9041
9042                 if (need_clear) {
9043                         /*
9044                          * When we mount with old space cache, we need to
9045                          * set BTRFS_DC_CLEAR and set dirty flag.
9046                          *
9047                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9048                          *    truncate the old free space cache inode and
9049                          *    setup a new one.
9050                          * b) Setting 'dirty flag' makes sure that we flush
9051                          *    the new space cache info onto disk.
9052                          */
9053                         cache->disk_cache_state = BTRFS_DC_CLEAR;
9054                         if (btrfs_test_opt(root, SPACE_CACHE))
9055                                 cache->dirty = 1;
9056                 }
9057
9058                 read_extent_buffer(leaf, &cache->item,
9059                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9060                                    sizeof(cache->item));
9061                 cache->flags = btrfs_block_group_flags(&cache->item);
9062
9063                 key.objectid = found_key.objectid + found_key.offset;
9064                 btrfs_release_path(path);
9065
9066                 /*
9067                  * We need to exclude the super stripes now so that the space
9068                  * info has super bytes accounted for, otherwise we'll think
9069                  * we have more space than we actually do.
9070                  */
9071                 ret = exclude_super_stripes(root, cache);
9072                 if (ret) {
9073                         /*
9074                          * We may have excluded something, so call this just in
9075                          * case.
9076                          */
9077                         free_excluded_extents(root, cache);
9078                         btrfs_put_block_group(cache);
9079                         goto error;
9080                 }
9081
9082                 /*
9083                  * check for two cases, either we are full, and therefore
9084                  * don't need to bother with the caching work since we won't
9085                  * find any space, or we are empty, and we can just add all
9086                  * the space in and be done with it.  This saves us _alot_ of
9087                  * time, particularly in the full case.
9088                  */
9089                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
9090                         cache->last_byte_to_unpin = (u64)-1;
9091                         cache->cached = BTRFS_CACHE_FINISHED;
9092                         free_excluded_extents(root, cache);
9093                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9094                         cache->last_byte_to_unpin = (u64)-1;
9095                         cache->cached = BTRFS_CACHE_FINISHED;
9096                         add_new_free_space(cache, root->fs_info,
9097                                            found_key.objectid,
9098                                            found_key.objectid +
9099                                            found_key.offset);
9100                         free_excluded_extents(root, cache);
9101                 }
9102
9103                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
9104                 if (ret) {
9105                         btrfs_remove_free_space_cache(cache);
9106                         btrfs_put_block_group(cache);
9107                         goto error;
9108                 }
9109
9110                 ret = update_space_info(info, cache->flags, found_key.offset,
9111                                         btrfs_block_group_used(&cache->item),
9112                                         &space_info);
9113                 if (ret) {
9114                         btrfs_remove_free_space_cache(cache);
9115                         spin_lock(&info->block_group_cache_lock);
9116                         rb_erase(&cache->cache_node,
9117                                  &info->block_group_cache_tree);
9118                         spin_unlock(&info->block_group_cache_lock);
9119                         btrfs_put_block_group(cache);
9120                         goto error;
9121                 }
9122
9123                 cache->space_info = space_info;
9124                 spin_lock(&cache->space_info->lock);
9125                 cache->space_info->bytes_readonly += cache->bytes_super;
9126                 spin_unlock(&cache->space_info->lock);
9127
9128                 __link_block_group(space_info, cache);
9129
9130                 set_avail_alloc_bits(root->fs_info, cache->flags);
9131                 if (btrfs_chunk_readonly(root, cache->key.objectid))
9132                         set_block_group_ro(cache, 1);
9133         }
9134
9135         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
9136                 if (!(get_alloc_profile(root, space_info->flags) &
9137                       (BTRFS_BLOCK_GROUP_RAID10 |
9138                        BTRFS_BLOCK_GROUP_RAID1 |
9139                        BTRFS_BLOCK_GROUP_RAID5 |
9140                        BTRFS_BLOCK_GROUP_RAID6 |
9141                        BTRFS_BLOCK_GROUP_DUP)))
9142                         continue;
9143                 /*
9144                  * avoid allocating from un-mirrored block group if there are
9145                  * mirrored block groups.
9146                  */
9147                 list_for_each_entry(cache,
9148                                 &space_info->block_groups[BTRFS_RAID_RAID0],
9149                                 list)
9150                         set_block_group_ro(cache, 1);
9151                 list_for_each_entry(cache,
9152                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
9153                                 list)
9154                         set_block_group_ro(cache, 1);
9155         }
9156
9157         init_global_block_rsv(info);
9158         ret = 0;
9159 error:
9160         btrfs_free_path(path);
9161         return ret;
9162 }
9163
9164 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
9165                                        struct btrfs_root *root)
9166 {
9167         struct btrfs_block_group_cache *block_group, *tmp;
9168         struct btrfs_root *extent_root = root->fs_info->extent_root;
9169         struct btrfs_block_group_item item;
9170         struct btrfs_key key;
9171         int ret = 0;
9172
9173         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs,
9174                                  new_bg_list) {
9175                 list_del_init(&block_group->new_bg_list);
9176
9177                 if (ret)
9178                         continue;
9179
9180                 spin_lock(&block_group->lock);
9181                 memcpy(&item, &block_group->item, sizeof(item));
9182                 memcpy(&key, &block_group->key, sizeof(key));
9183                 spin_unlock(&block_group->lock);
9184
9185                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
9186                                         sizeof(item));
9187                 if (ret)
9188                         btrfs_abort_transaction(trans, extent_root, ret);
9189                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
9190                                                key.objectid, key.offset);
9191                 if (ret)
9192                         btrfs_abort_transaction(trans, extent_root, ret);
9193         }
9194 }
9195
9196 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
9197                            struct btrfs_root *root, u64 bytes_used,
9198                            u64 type, u64 chunk_objectid, u64 chunk_offset,
9199                            u64 size)
9200 {
9201         int ret;
9202         struct btrfs_root *extent_root;
9203         struct btrfs_block_group_cache *cache;
9204
9205         extent_root = root->fs_info->extent_root;
9206
9207         btrfs_set_log_full_commit(root->fs_info, trans);
9208
9209         cache = btrfs_create_block_group_cache(root, chunk_offset, size);
9210         if (!cache)
9211                 return -ENOMEM;
9212
9213         btrfs_set_block_group_used(&cache->item, bytes_used);
9214         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
9215         btrfs_set_block_group_flags(&cache->item, type);
9216
9217         cache->flags = type;
9218         cache->last_byte_to_unpin = (u64)-1;
9219         cache->cached = BTRFS_CACHE_FINISHED;
9220         ret = exclude_super_stripes(root, cache);
9221         if (ret) {
9222                 /*
9223                  * We may have excluded something, so call this just in
9224                  * case.
9225                  */
9226                 free_excluded_extents(root, cache);
9227                 btrfs_put_block_group(cache);
9228                 return ret;
9229         }
9230
9231         add_new_free_space(cache, root->fs_info, chunk_offset,
9232                            chunk_offset + size);
9233
9234         free_excluded_extents(root, cache);
9235
9236         ret = btrfs_add_block_group_cache(root->fs_info, cache);
9237         if (ret) {
9238                 btrfs_remove_free_space_cache(cache);
9239                 btrfs_put_block_group(cache);
9240                 return ret;
9241         }
9242
9243         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
9244                                 &cache->space_info);
9245         if (ret) {
9246                 btrfs_remove_free_space_cache(cache);
9247                 spin_lock(&root->fs_info->block_group_cache_lock);
9248                 rb_erase(&cache->cache_node,
9249                          &root->fs_info->block_group_cache_tree);
9250                 spin_unlock(&root->fs_info->block_group_cache_lock);
9251                 btrfs_put_block_group(cache);
9252                 return ret;
9253         }
9254         update_global_block_rsv(root->fs_info);
9255
9256         spin_lock(&cache->space_info->lock);
9257         cache->space_info->bytes_readonly += cache->bytes_super;
9258         spin_unlock(&cache->space_info->lock);
9259
9260         __link_block_group(cache->space_info, cache);
9261
9262         list_add_tail(&cache->new_bg_list, &trans->new_bgs);
9263
9264         set_avail_alloc_bits(extent_root->fs_info, type);
9265
9266         return 0;
9267 }
9268
9269 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
9270 {
9271         u64 extra_flags = chunk_to_extended(flags) &
9272                                 BTRFS_EXTENDED_PROFILE_MASK;
9273
9274         write_seqlock(&fs_info->profiles_lock);
9275         if (flags & BTRFS_BLOCK_GROUP_DATA)
9276                 fs_info->avail_data_alloc_bits &= ~extra_flags;
9277         if (flags & BTRFS_BLOCK_GROUP_METADATA)
9278                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
9279         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
9280                 fs_info->avail_system_alloc_bits &= ~extra_flags;
9281         write_sequnlock(&fs_info->profiles_lock);
9282 }
9283
9284 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
9285                              struct btrfs_root *root, u64 group_start)
9286 {
9287         struct btrfs_path *path;
9288         struct btrfs_block_group_cache *block_group;
9289         struct btrfs_free_cluster *cluster;
9290         struct btrfs_root *tree_root = root->fs_info->tree_root;
9291         struct btrfs_key key;
9292         struct inode *inode;
9293         struct kobject *kobj = NULL;
9294         int ret;
9295         int index;
9296         int factor;
9297
9298         root = root->fs_info->extent_root;
9299
9300         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
9301         BUG_ON(!block_group);
9302         BUG_ON(!block_group->ro);
9303
9304         /*
9305          * Free the reserved super bytes from this block group before
9306          * remove it.
9307          */
9308         free_excluded_extents(root, block_group);
9309
9310         memcpy(&key, &block_group->key, sizeof(key));
9311         index = get_block_group_index(block_group);
9312         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
9313                                   BTRFS_BLOCK_GROUP_RAID1 |
9314                                   BTRFS_BLOCK_GROUP_RAID10))
9315                 factor = 2;
9316         else
9317                 factor = 1;
9318
9319         /* make sure this block group isn't part of an allocation cluster */
9320         cluster = &root->fs_info->data_alloc_cluster;
9321         spin_lock(&cluster->refill_lock);
9322         btrfs_return_cluster_to_free_space(block_group, cluster);
9323         spin_unlock(&cluster->refill_lock);
9324
9325         /*
9326          * make sure this block group isn't part of a metadata
9327          * allocation cluster
9328          */
9329         cluster = &root->fs_info->meta_alloc_cluster;
9330         spin_lock(&cluster->refill_lock);
9331         btrfs_return_cluster_to_free_space(block_group, cluster);
9332         spin_unlock(&cluster->refill_lock);
9333
9334         path = btrfs_alloc_path();
9335         if (!path) {
9336                 ret = -ENOMEM;
9337                 goto out;
9338         }
9339
9340         inode = lookup_free_space_inode(tree_root, block_group, path);
9341         if (!IS_ERR(inode)) {
9342                 ret = btrfs_orphan_add(trans, inode);
9343                 if (ret) {
9344                         btrfs_add_delayed_iput(inode);
9345                         goto out;
9346                 }
9347                 clear_nlink(inode);
9348                 /* One for the block groups ref */
9349                 spin_lock(&block_group->lock);
9350                 if (block_group->iref) {
9351                         block_group->iref = 0;
9352                         block_group->inode = NULL;
9353                         spin_unlock(&block_group->lock);
9354                         iput(inode);
9355                 } else {
9356                         spin_unlock(&block_group->lock);
9357                 }
9358                 /* One for our lookup ref */
9359                 btrfs_add_delayed_iput(inode);
9360         }
9361
9362         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
9363         key.offset = block_group->key.objectid;
9364         key.type = 0;
9365
9366         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
9367         if (ret < 0)
9368                 goto out;
9369         if (ret > 0)
9370                 btrfs_release_path(path);
9371         if (ret == 0) {
9372                 ret = btrfs_del_item(trans, tree_root, path);
9373                 if (ret)
9374                         goto out;
9375                 btrfs_release_path(path);
9376         }
9377
9378         spin_lock(&root->fs_info->block_group_cache_lock);
9379         rb_erase(&block_group->cache_node,
9380                  &root->fs_info->block_group_cache_tree);
9381
9382         if (root->fs_info->first_logical_byte == block_group->key.objectid)
9383                 root->fs_info->first_logical_byte = (u64)-1;
9384         spin_unlock(&root->fs_info->block_group_cache_lock);
9385
9386         down_write(&block_group->space_info->groups_sem);
9387         /*
9388          * we must use list_del_init so people can check to see if they
9389          * are still on the list after taking the semaphore
9390          */
9391         list_del_init(&block_group->list);
9392         if (list_empty(&block_group->space_info->block_groups[index])) {
9393                 kobj = block_group->space_info->block_group_kobjs[index];
9394                 block_group->space_info->block_group_kobjs[index] = NULL;
9395                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
9396         }
9397         up_write(&block_group->space_info->groups_sem);
9398         if (kobj) {
9399                 kobject_del(kobj);
9400                 kobject_put(kobj);
9401         }
9402
9403         if (block_group->cached == BTRFS_CACHE_STARTED)
9404                 wait_block_group_cache_done(block_group);
9405
9406         btrfs_remove_free_space_cache(block_group);
9407
9408         spin_lock(&block_group->space_info->lock);
9409         block_group->space_info->total_bytes -= block_group->key.offset;
9410         block_group->space_info->bytes_readonly -= block_group->key.offset;
9411         block_group->space_info->disk_total -= block_group->key.offset * factor;
9412         spin_unlock(&block_group->space_info->lock);
9413
9414         memcpy(&key, &block_group->key, sizeof(key));
9415
9416         btrfs_clear_space_info_full(root->fs_info);
9417
9418         btrfs_put_block_group(block_group);
9419         btrfs_put_block_group(block_group);
9420
9421         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
9422         if (ret > 0)
9423                 ret = -EIO;
9424         if (ret < 0)
9425                 goto out;
9426
9427         ret = btrfs_del_item(trans, root, path);
9428 out:
9429         btrfs_free_path(path);
9430         return ret;
9431 }
9432
9433 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
9434 {
9435         struct btrfs_space_info *space_info;
9436         struct btrfs_super_block *disk_super;
9437         u64 features;
9438         u64 flags;
9439         int mixed = 0;
9440         int ret;
9441
9442         disk_super = fs_info->super_copy;
9443         if (!btrfs_super_root(disk_super))
9444                 return 1;
9445
9446         features = btrfs_super_incompat_flags(disk_super);
9447         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
9448                 mixed = 1;
9449
9450         flags = BTRFS_BLOCK_GROUP_SYSTEM;
9451         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
9452         if (ret)
9453                 goto out;
9454
9455         if (mixed) {
9456                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
9457                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
9458         } else {
9459                 flags = BTRFS_BLOCK_GROUP_METADATA;
9460                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
9461                 if (ret)
9462                         goto out;
9463
9464                 flags = BTRFS_BLOCK_GROUP_DATA;
9465                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
9466         }
9467 out:
9468         return ret;
9469 }
9470
9471 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
9472 {
9473         return unpin_extent_range(root, start, end);
9474 }
9475
9476 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
9477                                u64 num_bytes, u64 *actual_bytes)
9478 {
9479         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
9480 }
9481
9482 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
9483 {
9484         struct btrfs_fs_info *fs_info = root->fs_info;
9485         struct btrfs_block_group_cache *cache = NULL;
9486         u64 group_trimmed;
9487         u64 start;
9488         u64 end;
9489         u64 trimmed = 0;
9490         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
9491         int ret = 0;
9492
9493         /*
9494          * try to trim all FS space, our block group may start from non-zero.
9495          */
9496         if (range->len == total_bytes)
9497                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
9498         else
9499                 cache = btrfs_lookup_block_group(fs_info, range->start);
9500
9501         while (cache) {
9502                 if (cache->key.objectid >= (range->start + range->len)) {
9503                         btrfs_put_block_group(cache);
9504                         break;
9505                 }
9506
9507                 start = max(range->start, cache->key.objectid);
9508                 end = min(range->start + range->len,
9509                                 cache->key.objectid + cache->key.offset);
9510
9511                 if (end - start >= range->minlen) {
9512                         if (!block_group_cache_done(cache)) {
9513                                 ret = cache_block_group(cache, 0);
9514                                 if (ret) {
9515                                         btrfs_put_block_group(cache);
9516                                         break;
9517                                 }
9518                                 ret = wait_block_group_cache_done(cache);
9519                                 if (ret) {
9520                                         btrfs_put_block_group(cache);
9521                                         break;
9522                                 }
9523                         }
9524                         ret = btrfs_trim_block_group(cache,
9525                                                      &group_trimmed,
9526                                                      start,
9527                                                      end,
9528                                                      range->minlen);
9529
9530                         trimmed += group_trimmed;
9531                         if (ret) {
9532                                 btrfs_put_block_group(cache);
9533                                 break;
9534                         }
9535                 }
9536
9537                 cache = next_block_group(fs_info->tree_root, cache);
9538         }
9539
9540         range->len = trimmed;
9541         return ret;
9542 }
9543
9544 /*
9545  * btrfs_{start,end}_write() is similar to mnt_{want, drop}_write(),
9546  * they are used to prevent the some tasks writing data into the page cache
9547  * by nocow before the subvolume is snapshoted, but flush the data into
9548  * the disk after the snapshot creation.
9549  */
9550 void btrfs_end_nocow_write(struct btrfs_root *root)
9551 {
9552         percpu_counter_dec(&root->subv_writers->counter);
9553         /*
9554          * Make sure counter is updated before we wake up
9555          * waiters.
9556          */
9557         smp_mb();
9558         if (waitqueue_active(&root->subv_writers->wait))
9559                 wake_up(&root->subv_writers->wait);
9560 }
9561
9562 int btrfs_start_nocow_write(struct btrfs_root *root)
9563 {
9564         if (unlikely(atomic_read(&root->will_be_snapshoted)))
9565                 return 0;
9566
9567         percpu_counter_inc(&root->subv_writers->counter);
9568         /*
9569          * Make sure counter is updated before we check for snapshot creation.
9570          */
9571         smp_mb();
9572         if (unlikely(atomic_read(&root->will_be_snapshoted))) {
9573                 btrfs_end_nocow_write(root);
9574                 return 0;
9575         }
9576         return 1;
9577 }