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_trans_handle *trans,
  78                               struct btrfs_root *root, u64 bytenr,
  79                               u64 num_bytes, int alloc);
  80 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  81                                 struct btrfs_root *root,
  82                                 struct btrfs_delayed_ref_node *node, u64 parent,
  83                                 u64 root_objectid, u64 owner_objectid,
  84                                 u64 owner_offset, int refs_to_drop,
  85                                 struct btrfs_delayed_extent_op *extra_op);
  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->caching_ctl) {
 319                 spin_unlock(&cache->lock);
 320                 return NULL;
 321         }
 322
 323         ctl = cache->caching_ctl;
 324         atomic_inc(&ctl->count);
 325         spin_unlock(&cache->lock);
 326         return ctl;
 327 }
 328
 329 static void put_caching_control(struct btrfs_caching_control *ctl)
 330 {
 331         if (atomic_dec_and_test(&ctl->count))
 332                 kfree(ctl);
 333 }
 334
 335 /*
 336  * this is only called by cache_block_group, since we could have freed extents
 337  * we need to check the pinned_extents for any extents that can't be used yet
 338  * since their free space will be released as soon as the transaction commits.
 339  */
 340 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 341                               struct btrfs_fs_info *info, u64 start, u64 end)
 342 {
 343         u64 extent_start, extent_end, size, total_added = 0;
 344         int ret;
 345
 346         while (start < end) {
 347                 ret = find_first_extent_bit(info->pinned_extents, start,
 348                                             &extent_start, &extent_end,
 349                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 350                                             NULL);
 351                 if (ret)
 352                         break;
 353
 354                 if (extent_start <= start) {
 355                         start = extent_end + 1;
 356                 } else if (extent_start > start && extent_start < end) {
 357                         size = extent_start - start;
 358                         total_added += size;
 359                         ret = btrfs_add_free_space(block_group, start,
 360                                                    size);
 361                         BUG_ON(ret); /* -ENOMEM or logic error */
 362                         start = extent_end + 1;
 363                 } else {
 364                         break;
 365                 }
 366         }
 367
 368         if (start < end) {
 369                 size = end - start;
 370                 total_added += size;
 371                 ret = btrfs_add_free_space(block_group, start, size);
 372                 BUG_ON(ret); /* -ENOMEM or logic error */
 373         }
 374
 375         return total_added;
 376 }
 377
 378 static noinline void caching_thread(struct btrfs_work *work)
 379 {
 380         struct btrfs_block_group_cache *block_group;
 381         struct btrfs_fs_info *fs_info;
 382         struct btrfs_caching_control *caching_ctl;
 383         struct btrfs_root *extent_root;
 384         struct btrfs_path *path;
 385         struct extent_buffer *leaf;
 386         struct btrfs_key key;
 387         u64 total_found = 0;
 388         u64 last = 0;
 389         u32 nritems;
 390         int ret = -ENOMEM;
 391
 392         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 393         block_group = caching_ctl->block_group;
 394         fs_info = block_group->fs_info;
 395         extent_root = fs_info->extent_root;
 396
 397         path = btrfs_alloc_path();
 398         if (!path)
 399                 goto out;
 400
 401         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 402
 403         /*
 404          * We don't want to deadlock with somebody trying to allocate a new
 405          * extent for the extent root while also trying to search the extent
 406          * root to add free space.  So we skip locking and search the commit
 407          * root, since its read-only
 408          */
 409         path->skip_locking = 1;
 410         path->search_commit_root = 1;
 411         path->reada = 1;
 412
 413         key.objectid = last;
 414         key.offset = 0;
 415         key.type = BTRFS_EXTENT_ITEM_KEY;
 416 again:
 417         mutex_lock(&caching_ctl->mutex);
 418         /* need to make sure the commit_root doesn't disappear */
 419         down_read(&fs_info->commit_root_sem);
 420
 421 next:
 422         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 423         if (ret < 0)
 424                 goto err;
 425
 426         leaf = path->nodes[0];
 427         nritems = btrfs_header_nritems(leaf);
 428
 429         while (1) {
 430                 if (btrfs_fs_closing(fs_info) > 1) {
 431                         last = (u64)-1;
 432                         break;
 433                 }
 434
 435                 if (path->slots[0] < nritems) {
 436                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 437                 } else {
 438                         ret = find_next_key(path, 0, &key);
 439                         if (ret)
 440                                 break;
 441
 442                         if (need_resched() ||
 443                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 444                                 caching_ctl->progress = last;
 445                                 btrfs_release_path(path);
 446                                 up_read(&fs_info->commit_root_sem);
 447                                 mutex_unlock(&caching_ctl->mutex);
 448                                 cond_resched();
 449                                 goto again;
 450                         }
 451
 452                         ret = btrfs_next_leaf(extent_root, path);
 453                         if (ret < 0)
 454                                 goto err;
 455                         if (ret)
 456                                 break;
 457                         leaf = path->nodes[0];
 458                         nritems = btrfs_header_nritems(leaf);
 459                         continue;
 460                 }
 461
 462                 if (key.objectid < last) {
 463                         key.objectid = last;
 464                         key.offset = 0;
 465                         key.type = BTRFS_EXTENT_ITEM_KEY;
 466
 467                         caching_ctl->progress = last;
 468                         btrfs_release_path(path);
 469                         goto next;
 470                 }
 471
 472                 if (key.objectid < block_group->key.objectid) {
 473                         path->slots[0]++;
 474                         continue;
 475                 }
 476
 477                 if (key.objectid >= block_group->key.objectid +
 478                     block_group->key.offset)
 479                         break;
 480
 481                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 482                     key.type == BTRFS_METADATA_ITEM_KEY) {
 483                         total_found += add_new_free_space(block_group,
 484                                                           fs_info, last,
 485                                                           key.objectid);
 486                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 487                                 last = key.objectid +
 488                                         fs_info->tree_root->nodesize;
 489                         else
 490                                 last = key.objectid + key.offset;
 491
 492                         if (total_found > (1024 * 1024 * 2)) {
 493                                 total_found = 0;
 494                                 wake_up(&caching_ctl->wait);
 495                         }
 496                 }
 497                 path->slots[0]++;
 498         }
 499         ret = 0;
 500
 501         total_found += add_new_free_space(block_group, fs_info, last,
 502                                           block_group->key.objectid +
 503                                           block_group->key.offset);
 504         caching_ctl->progress = (u64)-1;
 505
 506         spin_lock(&block_group->lock);
 507         block_group->caching_ctl = NULL;
 508         block_group->cached = BTRFS_CACHE_FINISHED;
 509         spin_unlock(&block_group->lock);
 510
 511 err:
 512         btrfs_free_path(path);
 513         up_read(&fs_info->commit_root_sem);
 514
 515         free_excluded_extents(extent_root, block_group);
 516
 517         mutex_unlock(&caching_ctl->mutex);
 518 out:
 519         if (ret) {
 520                 spin_lock(&block_group->lock);
 521                 block_group->caching_ctl = NULL;
 522                 block_group->cached = BTRFS_CACHE_ERROR;
 523                 spin_unlock(&block_group->lock);
 524         }
 525         wake_up(&caching_ctl->wait);
 526
 527         put_caching_control(caching_ctl);
 528         btrfs_put_block_group(block_group);
 529 }
 530
 531 static int cache_block_group(struct btrfs_block_group_cache *cache,
 532                              int load_cache_only)
 533 {
 534         DEFINE_WAIT(wait);
 535         struct btrfs_fs_info *fs_info = cache->fs_info;
 536         struct btrfs_caching_control *caching_ctl;
 537         int ret = 0;
 538
 539         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 540         if (!caching_ctl)
 541                 return -ENOMEM;
 542
 543         INIT_LIST_HEAD(&caching_ctl->list);
 544         mutex_init(&caching_ctl->mutex);
 545         init_waitqueue_head(&caching_ctl->wait);
 546         caching_ctl->block_group = cache;
 547         caching_ctl->progress = cache->key.objectid;
 548         atomic_set(&caching_ctl->count, 1);
 549         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 550                         caching_thread, NULL, NULL);
 551
 552         spin_lock(&cache->lock);
 553         /*
 554          * This should be a rare occasion, but this could happen I think in the
 555          * case where one thread starts to load the space cache info, and then
 556          * some other thread starts a transaction commit which tries to do an
 557          * allocation while the other thread is still loading the space cache
 558          * info.  The previous loop should have kept us from choosing this block
 559          * group, but if we've moved to the state where we will wait on caching
 560          * block groups we need to first check if we're doing a fast load here,
 561          * so we can wait for it to finish, otherwise we could end up allocating
 562          * from a block group who's cache gets evicted for one reason or
 563          * another.
 564          */
 565         while (cache->cached == BTRFS_CACHE_FAST) {
 566                 struct btrfs_caching_control *ctl;
 567
 568                 ctl = cache->caching_ctl;
 569                 atomic_inc(&ctl->count);
 570                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 571                 spin_unlock(&cache->lock);
 572
 573                 schedule();
 574
 575                 finish_wait(&ctl->wait, &wait);
 576                 put_caching_control(ctl);
 577                 spin_lock(&cache->lock);
 578         }
 579
 580         if (cache->cached != BTRFS_CACHE_NO) {
 581                 spin_unlock(&cache->lock);
 582                 kfree(caching_ctl);
 583                 return 0;
 584         }
 585         WARN_ON(cache->caching_ctl);
 586         cache->caching_ctl = caching_ctl;
 587         cache->cached = BTRFS_CACHE_FAST;
 588         spin_unlock(&cache->lock);
 589
 590         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 591                 mutex_lock(&caching_ctl->mutex);
 592                 ret = load_free_space_cache(fs_info, cache);
 593
 594                 spin_lock(&cache->lock);
 595                 if (ret == 1) {
 596                         cache->caching_ctl = NULL;
 597                         cache->cached = BTRFS_CACHE_FINISHED;
 598                         cache->last_byte_to_unpin = (u64)-1;
 599                         caching_ctl->progress = (u64)-1;
 600                 } else {
 601                         if (load_cache_only) {
 602                                 cache->caching_ctl = NULL;
 603                                 cache->cached = BTRFS_CACHE_NO;
 604                         } else {
 605                                 cache->cached = BTRFS_CACHE_STARTED;
 606                                 cache->has_caching_ctl = 1;
 607                         }
 608                 }
 609                 spin_unlock(&cache->lock);
 610                 mutex_unlock(&caching_ctl->mutex);
 611
 612                 wake_up(&caching_ctl->wait);
 613                 if (ret == 1) {
 614                         put_caching_control(caching_ctl);
 615                         free_excluded_extents(fs_info->extent_root, cache);
 616                         return 0;
 617                 }
 618         } else {
 619                 /*
 620                  * We are not going to do the fast caching, set cached to the
 621                  * appropriate value and wakeup any waiters.
 622                  */
 623                 spin_lock(&cache->lock);
 624                 if (load_cache_only) {
 625                         cache->caching_ctl = NULL;
 626                         cache->cached = BTRFS_CACHE_NO;
 627                 } else {
 628                         cache->cached = BTRFS_CACHE_STARTED;
 629                         cache->has_caching_ctl = 1;
 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 data extent at a given offset */
 714 int btrfs_lookup_data_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         btrfs_free_path(path);
 730         return ret;
 731 }
 732
 733 /*
 734  * helper function to lookup reference count and flags of a tree block.
 735  *
 736  * the head node for delayed ref is used to store the sum of all the
 737  * reference count modifications queued up in the rbtree. the head
 738  * node may also store the extent flags to set. This way you can check
 739  * to see what the reference count and extent flags would be if all of
 740  * the delayed refs are not processed.
 741  */
 742 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 743                              struct btrfs_root *root, u64 bytenr,
 744                              u64 offset, int metadata, u64 *refs, u64 *flags)
 745 {
 746         struct btrfs_delayed_ref_head *head;
 747         struct btrfs_delayed_ref_root *delayed_refs;
 748         struct btrfs_path *path;
 749         struct btrfs_extent_item *ei;
 750         struct extent_buffer *leaf;
 751         struct btrfs_key key;
 752         u32 item_size;
 753         u64 num_refs;
 754         u64 extent_flags;
 755         int ret;
 756
 757         /*
 758          * If we don't have skinny metadata, don't bother doing anything
 759          * different
 760          */
 761         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 762                 offset = root->nodesize;
 763                 metadata = 0;
 764         }
 765
 766         path = btrfs_alloc_path();
 767         if (!path)
 768                 return -ENOMEM;
 769
 770         if (!trans) {
 771                 path->skip_locking = 1;
 772                 path->search_commit_root = 1;
 773         }
 774
 775 search_again:
 776         key.objectid = bytenr;
 777         key.offset = offset;
 778         if (metadata)
 779                 key.type = BTRFS_METADATA_ITEM_KEY;
 780         else
 781                 key.type = BTRFS_EXTENT_ITEM_KEY;
 782
 783         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 784                                 &key, path, 0, 0);
 785         if (ret < 0)
 786                 goto out_free;
 787
 788         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 789                 if (path->slots[0]) {
 790                         path->slots[0]--;
 791                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 792                                               path->slots[0]);
 793                         if (key.objectid == bytenr &&
 794                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 795                             key.offset == root->nodesize)
 796                                 ret = 0;
 797                 }
 798         }
 799
 800         if (ret == 0) {
 801                 leaf = path->nodes[0];
 802                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 803                 if (item_size >= sizeof(*ei)) {
 804                         ei = btrfs_item_ptr(leaf, path->slots[0],
 805                                             struct btrfs_extent_item);
 806                         num_refs = btrfs_extent_refs(leaf, ei);
 807                         extent_flags = btrfs_extent_flags(leaf, ei);
 808                 } else {
 809 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 810                         struct btrfs_extent_item_v0 *ei0;
 811                         BUG_ON(item_size != sizeof(*ei0));
 812                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 813                                              struct btrfs_extent_item_v0);
 814                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 815                         /* FIXME: this isn't correct for data */
 816                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 817 #else
 818                         BUG();
 819 #endif
 820                 }
 821                 BUG_ON(num_refs == 0);
 822         } else {
 823                 num_refs = 0;
 824                 extent_flags = 0;
 825                 ret = 0;
 826         }
 827
 828         if (!trans)
 829                 goto out;
 830
 831         delayed_refs = &trans->transaction->delayed_refs;
 832         spin_lock(&delayed_refs->lock);
 833         head = btrfs_find_delayed_ref_head(trans, bytenr);
 834         if (head) {
 835                 if (!mutex_trylock(&head->mutex)) {
 836                         atomic_inc(&head->node.refs);
 837                         spin_unlock(&delayed_refs->lock);
 838
 839                         btrfs_release_path(path);
 840
 841                         /*
 842                          * Mutex was contended, block until it's released and try
 843                          * again
 844                          */
 845                         mutex_lock(&head->mutex);
 846                         mutex_unlock(&head->mutex);
 847                         btrfs_put_delayed_ref(&head->node);
 848                         goto search_again;
 849                 }
 850                 spin_lock(&head->lock);
 851                 if (head->extent_op && head->extent_op->update_flags)
 852                         extent_flags |= head->extent_op->flags_to_set;
 853                 else
 854                         BUG_ON(num_refs == 0);
 855
 856                 num_refs += head->node.ref_mod;
 857                 spin_unlock(&head->lock);
 858                 mutex_unlock(&head->mutex);
 859         }
 860         spin_unlock(&delayed_refs->lock);
 861 out:
 862         WARN_ON(num_refs == 0);
 863         if (refs)
 864                 *refs = num_refs;
 865         if (flags)
 866                 *flags = extent_flags;
 867 out_free:
 868         btrfs_free_path(path);
 869         return ret;
 870 }
 871
 872 /*
 873  * Back reference rules.  Back refs have three main goals:
 874  *
 875  * 1) differentiate between all holders of references to an extent so that
 876  *    when a reference is dropped we can make sure it was a valid reference
 877  *    before freeing the extent.
 878  *
 879  * 2) Provide enough information to quickly find the holders of an extent
 880  *    if we notice a given block is corrupted or bad.
 881  *
 882  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 883  *    maintenance.  This is actually the same as #2, but with a slightly
 884  *    different use case.
 885  *
 886  * There are two kinds of back refs. The implicit back refs is optimized
 887  * for pointers in non-shared tree blocks. For a given pointer in a block,
 888  * back refs of this kind provide information about the block's owner tree
 889  * and the pointer's key. These information allow us to find the block by
 890  * b-tree searching. The full back refs is for pointers in tree blocks not
 891  * referenced by their owner trees. The location of tree block is recorded
 892  * in the back refs. Actually the full back refs is generic, and can be
 893  * used in all cases the implicit back refs is used. The major shortcoming
 894  * of the full back refs is its overhead. Every time a tree block gets
 895  * COWed, we have to update back refs entry for all pointers in it.
 896  *
 897  * For a newly allocated tree block, we use implicit back refs for
 898  * pointers in it. This means most tree related operations only involve
 899  * implicit back refs. For a tree block created in old transaction, the
 900  * only way to drop a reference to it is COW it. So we can detect the
 901  * event that tree block loses its owner tree's reference and do the
 902  * back refs conversion.
 903  *
 904  * When a tree block is COW'd through a tree, there are four cases:
 905  *
 906  * The reference count of the block is one and the tree is the block's
 907  * owner tree. Nothing to do in this case.
 908  *
 909  * The reference count of the block is one and the tree is not the
 910  * block's owner tree. In this case, full back refs is used for pointers
 911  * in the block. Remove these full back refs, add implicit back refs for
 912  * every pointers in the new block.
 913  *
 914  * The reference count of the block is greater than one and the tree is
 915  * the block's owner tree. In this case, implicit back refs is used for
 916  * pointers in the block. Add full back refs for every pointers in the
 917  * block, increase lower level extents' reference counts. The original
 918  * implicit back refs are entailed to the new block.
 919  *
 920  * The reference count of the block is greater than one and the tree is
 921  * not the block's owner tree. Add implicit back refs for every pointer in
 922  * the new block, increase lower level extents' reference count.
 923  *
 924  * Back Reference Key composing:
 925  *
 926  * The key objectid corresponds to the first byte in the extent,
 927  * The key type is used to differentiate between types of back refs.
 928  * There are different meanings of the key offset for different types
 929  * of back refs.
 930  *
 931  * File extents can be referenced by:
 932  *
 933  * - multiple snapshots, subvolumes, or different generations in one subvol
 934  * - different files inside a single subvolume
 935  * - different offsets inside a file (bookend extents in file.c)
 936  *
 937  * The extent ref structure for the implicit back refs has fields for:
 938  *
 939  * - Objectid of the subvolume root
 940  * - objectid of the file holding the reference
 941  * - original offset in the file
 942  * - how many bookend extents
 943  *
 944  * The key offset for the implicit back refs is hash of the first
 945  * three fields.
 946  *
 947  * The extent ref structure for the full back refs has field for:
 948  *
 949  * - number of pointers in the tree leaf
 950  *
 951  * The key offset for the implicit back refs is the first byte of
 952  * the tree leaf
 953  *
 954  * When a file extent is allocated, The implicit back refs is used.
 955  * the fields are filled in:
 956  *
 957  *     (root_key.objectid, inode objectid, offset in file, 1)
 958  *
 959  * When a file extent is removed file truncation, we find the
 960  * corresponding implicit back refs and check the following fields:
 961  *
 962  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 963  *
 964  * Btree extents can be referenced by:
 965  *
 966  * - Different subvolumes
 967  *
 968  * Both the implicit back refs and the full back refs for tree blocks
 969  * only consist of key. The key offset for the implicit back refs is
 970  * objectid of block's owner tree. The key offset for the full back refs
 971  * is the first byte of parent block.
 972  *
 973  * When implicit back refs is used, information about the lowest key and
 974  * level of the tree block are required. These information are stored in
 975  * tree block info structure.
 976  */
 977
 978 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 979 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 980                                   struct btrfs_root *root,
 981                                   struct btrfs_path *path,
 982                                   u64 owner, u32 extra_size)
 983 {
 984         struct btrfs_extent_item *item;
 985         struct btrfs_extent_item_v0 *ei0;
 986         struct btrfs_extent_ref_v0 *ref0;
 987         struct btrfs_tree_block_info *bi;
 988         struct extent_buffer *leaf;
 989         struct btrfs_key key;
 990         struct btrfs_key found_key;
 991         u32 new_size = sizeof(*item);
 992         u64 refs;
 993         int ret;
 994
 995         leaf = path->nodes[0];
 996         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 997
 998         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 999         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1000                              struct btrfs_extent_item_v0);
1001         refs = btrfs_extent_refs_v0(leaf, ei0);
1002
1003         if (owner == (u64)-1) {
1004                 while (1) {
1005                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1006                                 ret = btrfs_next_leaf(root, path);
1007                                 if (ret < 0)
1008                                         return ret;
1009                                 BUG_ON(ret > 0); /* Corruption */
1010                                 leaf = path->nodes[0];
1011                         }
1012                         btrfs_item_key_to_cpu(leaf, &found_key,
1013                                               path->slots[0]);
1014                         BUG_ON(key.objectid != found_key.objectid);
1015                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1016                                 path->slots[0]++;
1017                                 continue;
1018                         }
1019                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1020                                               struct btrfs_extent_ref_v0);
1021                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1022                         break;
1023                 }
1024         }
1025         btrfs_release_path(path);
1026
1027         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1028                 new_size += sizeof(*bi);
1029
1030         new_size -= sizeof(*ei0);
1031         ret = btrfs_search_slot(trans, root, &key, path,
1032                                 new_size + extra_size, 1);
1033         if (ret < 0)
1034                 return ret;
1035         BUG_ON(ret); /* Corruption */
1036
1037         btrfs_extend_item(root, path, new_size);
1038
1039         leaf = path->nodes[0];
1040         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1041         btrfs_set_extent_refs(leaf, item, refs);
1042         /* FIXME: get real generation */
1043         btrfs_set_extent_generation(leaf, item, 0);
1044         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1045                 btrfs_set_extent_flags(leaf, item,
1046                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1047                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1048                 bi = (struct btrfs_tree_block_info *)(item + 1);
1049                 /* FIXME: get first key of the block */
1050                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1051                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1052         } else {
1053                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1054         }
1055         btrfs_mark_buffer_dirty(leaf);
1056         return 0;
1057 }
1058 #endif
1059
1060 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1061 {
1062         u32 high_crc = ~(u32)0;
1063         u32 low_crc = ~(u32)0;
1064         __le64 lenum;
1065
1066         lenum = cpu_to_le64(root_objectid);
1067         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1068         lenum = cpu_to_le64(owner);
1069         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1070         lenum = cpu_to_le64(offset);
1071         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1072
1073         return ((u64)high_crc << 31) ^ (u64)low_crc;
1074 }
1075
1076 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1077                                      struct btrfs_extent_data_ref *ref)
1078 {
1079         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1080                                     btrfs_extent_data_ref_objectid(leaf, ref),
1081                                     btrfs_extent_data_ref_offset(leaf, ref));
1082 }
1083
1084 static int match_extent_data_ref(struct extent_buffer *leaf,
1085                                  struct btrfs_extent_data_ref *ref,
1086                                  u64 root_objectid, u64 owner, u64 offset)
1087 {
1088         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1089             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1090             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1091                 return 0;
1092         return 1;
1093 }
1094
1095 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1096                                            struct btrfs_root *root,
1097                                            struct btrfs_path *path,
1098                                            u64 bytenr, u64 parent,
1099                                            u64 root_objectid,
1100                                            u64 owner, u64 offset)
1101 {
1102         struct btrfs_key key;
1103         struct btrfs_extent_data_ref *ref;
1104         struct extent_buffer *leaf;
1105         u32 nritems;
1106         int ret;
1107         int recow;
1108         int err = -ENOENT;
1109
1110         key.objectid = bytenr;
1111         if (parent) {
1112                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1113                 key.offset = parent;
1114         } else {
1115                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1116                 key.offset = hash_extent_data_ref(root_objectid,
1117                                                   owner, offset);
1118         }
1119 again:
1120         recow = 0;
1121         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1122         if (ret < 0) {
1123                 err = ret;
1124                 goto fail;
1125         }
1126
1127         if (parent) {
1128                 if (!ret)
1129                         return 0;
1130 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1131                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1132                 btrfs_release_path(path);
1133                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1134                 if (ret < 0) {
1135                         err = ret;
1136                         goto fail;
1137                 }
1138                 if (!ret)
1139                         return 0;
1140 #endif
1141                 goto fail;
1142         }
1143
1144         leaf = path->nodes[0];
1145         nritems = btrfs_header_nritems(leaf);
1146         while (1) {
1147                 if (path->slots[0] >= nritems) {
1148                         ret = btrfs_next_leaf(root, path);
1149                         if (ret < 0)
1150                                 err = ret;
1151                         if (ret)
1152                                 goto fail;
1153
1154                         leaf = path->nodes[0];
1155                         nritems = btrfs_header_nritems(leaf);
1156                         recow = 1;
1157                 }
1158
1159                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1160                 if (key.objectid != bytenr ||
1161                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1162                         goto fail;
1163
1164                 ref = btrfs_item_ptr(leaf, path->slots[0],
1165                                      struct btrfs_extent_data_ref);
1166
1167                 if (match_extent_data_ref(leaf, ref, root_objectid,
1168                                           owner, offset)) {
1169                         if (recow) {
1170                                 btrfs_release_path(path);
1171                                 goto again;
1172                         }
1173                         err = 0;
1174                         break;
1175                 }
1176                 path->slots[0]++;
1177         }
1178 fail:
1179         return err;
1180 }
1181
1182 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1183                                            struct btrfs_root *root,
1184                                            struct btrfs_path *path,
1185                                            u64 bytenr, u64 parent,
1186                                            u64 root_objectid, u64 owner,
1187                                            u64 offset, int refs_to_add)
1188 {
1189         struct btrfs_key key;
1190         struct extent_buffer *leaf;
1191         u32 size;
1192         u32 num_refs;
1193         int ret;
1194
1195         key.objectid = bytenr;
1196         if (parent) {
1197                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1198                 key.offset = parent;
1199                 size = sizeof(struct btrfs_shared_data_ref);
1200         } else {
1201                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1202                 key.offset = hash_extent_data_ref(root_objectid,
1203                                                   owner, offset);
1204                 size = sizeof(struct btrfs_extent_data_ref);
1205         }
1206
1207         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1208         if (ret && ret != -EEXIST)
1209                 goto fail;
1210
1211         leaf = path->nodes[0];
1212         if (parent) {
1213                 struct btrfs_shared_data_ref *ref;
1214                 ref = btrfs_item_ptr(leaf, path->slots[0],
1215                                      struct btrfs_shared_data_ref);
1216                 if (ret == 0) {
1217                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1218                 } else {
1219                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1220                         num_refs += refs_to_add;
1221                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1222                 }
1223         } else {
1224                 struct btrfs_extent_data_ref *ref;
1225                 while (ret == -EEXIST) {
1226                         ref = btrfs_item_ptr(leaf, path->slots[0],
1227                                              struct btrfs_extent_data_ref);
1228                         if (match_extent_data_ref(leaf, ref, root_objectid,
1229                                                   owner, offset))
1230                                 break;
1231                         btrfs_release_path(path);
1232                         key.offset++;
1233                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1234                                                       size);
1235                         if (ret && ret != -EEXIST)
1236                                 goto fail;
1237
1238                         leaf = path->nodes[0];
1239                 }
1240                 ref = btrfs_item_ptr(leaf, path->slots[0],
1241                                      struct btrfs_extent_data_ref);
1242                 if (ret == 0) {
1243                         btrfs_set_extent_data_ref_root(leaf, ref,
1244                                                        root_objectid);
1245                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1246                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1247                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1248                 } else {
1249                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1250                         num_refs += refs_to_add;
1251                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1252                 }
1253         }
1254         btrfs_mark_buffer_dirty(leaf);
1255         ret = 0;
1256 fail:
1257         btrfs_release_path(path);
1258         return ret;
1259 }
1260
1261 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1262                                            struct btrfs_root *root,
1263                                            struct btrfs_path *path,
1264                                            int refs_to_drop, int *last_ref)
1265 {
1266         struct btrfs_key key;
1267         struct btrfs_extent_data_ref *ref1 = NULL;
1268         struct btrfs_shared_data_ref *ref2 = NULL;
1269         struct extent_buffer *leaf;
1270         u32 num_refs = 0;
1271         int ret = 0;
1272
1273         leaf = path->nodes[0];
1274         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1275
1276         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1277                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1278                                       struct btrfs_extent_data_ref);
1279                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1280         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1281                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1282                                       struct btrfs_shared_data_ref);
1283                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1284 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1285         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1286                 struct btrfs_extent_ref_v0 *ref0;
1287                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1288                                       struct btrfs_extent_ref_v0);
1289                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1290 #endif
1291         } else {
1292                 BUG();
1293         }
1294
1295         BUG_ON(num_refs < refs_to_drop);
1296         num_refs -= refs_to_drop;
1297
1298         if (num_refs == 0) {
1299                 ret = btrfs_del_item(trans, root, path);
1300                 *last_ref = 1;
1301         } else {
1302                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1303                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1304                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1305                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1306 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1307                 else {
1308                         struct btrfs_extent_ref_v0 *ref0;
1309                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1310                                         struct btrfs_extent_ref_v0);
1311                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1312                 }
1313 #endif
1314                 btrfs_mark_buffer_dirty(leaf);
1315         }
1316         return ret;
1317 }
1318
1319 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1320                                           struct btrfs_path *path,
1321                                           struct btrfs_extent_inline_ref *iref)
1322 {
1323         struct btrfs_key key;
1324         struct extent_buffer *leaf;
1325         struct btrfs_extent_data_ref *ref1;
1326         struct btrfs_shared_data_ref *ref2;
1327         u32 num_refs = 0;
1328
1329         leaf = path->nodes[0];
1330         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1331         if (iref) {
1332                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1333                     BTRFS_EXTENT_DATA_REF_KEY) {
1334                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1335                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1336                 } else {
1337                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1338                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1339                 }
1340         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1341                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1342                                       struct btrfs_extent_data_ref);
1343                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1344         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1345                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1346                                       struct btrfs_shared_data_ref);
1347                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1348 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1349         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1350                 struct btrfs_extent_ref_v0 *ref0;
1351                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1352                                       struct btrfs_extent_ref_v0);
1353                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1354 #endif
1355         } else {
1356                 WARN_ON(1);
1357         }
1358         return num_refs;
1359 }
1360
1361 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1362                                           struct btrfs_root *root,
1363                                           struct btrfs_path *path,
1364                                           u64 bytenr, u64 parent,
1365                                           u64 root_objectid)
1366 {
1367         struct btrfs_key key;
1368         int ret;
1369
1370         key.objectid = bytenr;
1371         if (parent) {
1372                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1373                 key.offset = parent;
1374         } else {
1375                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1376                 key.offset = root_objectid;
1377         }
1378
1379         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1380         if (ret > 0)
1381                 ret = -ENOENT;
1382 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1383         if (ret == -ENOENT && parent) {
1384                 btrfs_release_path(path);
1385                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1386                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1387                 if (ret > 0)
1388                         ret = -ENOENT;
1389         }
1390 #endif
1391         return ret;
1392 }
1393
1394 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1395                                           struct btrfs_root *root,
1396                                           struct btrfs_path *path,
1397                                           u64 bytenr, u64 parent,
1398                                           u64 root_objectid)
1399 {
1400         struct btrfs_key key;
1401         int ret;
1402
1403         key.objectid = bytenr;
1404         if (parent) {
1405                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1406                 key.offset = parent;
1407         } else {
1408                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1409                 key.offset = root_objectid;
1410         }
1411
1412         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1413         btrfs_release_path(path);
1414         return ret;
1415 }
1416
1417 static inline int extent_ref_type(u64 parent, u64 owner)
1418 {
1419         int type;
1420         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1421                 if (parent > 0)
1422                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1423                 else
1424                         type = BTRFS_TREE_BLOCK_REF_KEY;
1425         } else {
1426                 if (parent > 0)
1427                         type = BTRFS_SHARED_DATA_REF_KEY;
1428                 else
1429                         type = BTRFS_EXTENT_DATA_REF_KEY;
1430         }
1431         return type;
1432 }
1433
1434 static int find_next_key(struct btrfs_path *path, int level,
1435                          struct btrfs_key *key)
1436
1437 {
1438         for (; level < BTRFS_MAX_LEVEL; level++) {
1439                 if (!path->nodes[level])
1440                         break;
1441                 if (path->slots[level] + 1 >=
1442                     btrfs_header_nritems(path->nodes[level]))
1443                         continue;
1444                 if (level == 0)
1445                         btrfs_item_key_to_cpu(path->nodes[level], key,
1446                                               path->slots[level] + 1);
1447                 else
1448                         btrfs_node_key_to_cpu(path->nodes[level], key,
1449                                               path->slots[level] + 1);
1450                 return 0;
1451         }
1452         return 1;
1453 }
1454
1455 /*
1456  * look for inline back ref. if back ref is found, *ref_ret is set
1457  * to the address of inline back ref, and 0 is returned.
1458  *
1459  * if back ref isn't found, *ref_ret is set to the address where it
1460  * should be inserted, and -ENOENT is returned.
1461  *
1462  * if insert is true and there are too many inline back refs, the path
1463  * points to the extent item, and -EAGAIN is returned.
1464  *
1465  * NOTE: inline back refs are ordered in the same way that back ref
1466  *       items in the tree are ordered.
1467  */
1468 static noinline_for_stack
1469 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1470                                  struct btrfs_root *root,
1471                                  struct btrfs_path *path,
1472                                  struct btrfs_extent_inline_ref **ref_ret,
1473                                  u64 bytenr, u64 num_bytes,
1474                                  u64 parent, u64 root_objectid,
1475                                  u64 owner, u64 offset, int insert)
1476 {
1477         struct btrfs_key key;
1478         struct extent_buffer *leaf;
1479         struct btrfs_extent_item *ei;
1480         struct btrfs_extent_inline_ref *iref;
1481         u64 flags;
1482         u64 item_size;
1483         unsigned long ptr;
1484         unsigned long end;
1485         int extra_size;
1486         int type;
1487         int want;
1488         int ret;
1489         int err = 0;
1490         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1491                                                  SKINNY_METADATA);
1492
1493         key.objectid = bytenr;
1494         key.type = BTRFS_EXTENT_ITEM_KEY;
1495         key.offset = num_bytes;
1496
1497         want = extent_ref_type(parent, owner);
1498         if (insert) {
1499                 extra_size = btrfs_extent_inline_ref_size(want);
1500                 path->keep_locks = 1;
1501         } else
1502                 extra_size = -1;
1503
1504         /*
1505          * Owner is our parent level, so we can just add one to get the level
1506          * for the block we are interested in.
1507          */
1508         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1509                 key.type = BTRFS_METADATA_ITEM_KEY;
1510                 key.offset = owner;
1511         }
1512
1513 again:
1514         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1515         if (ret < 0) {
1516                 err = ret;
1517                 goto out;
1518         }
1519
1520         /*
1521          * We may be a newly converted file system which still has the old fat
1522          * extent entries for metadata, so try and see if we have one of those.
1523          */
1524         if (ret > 0 && skinny_metadata) {
1525                 skinny_metadata = false;
1526                 if (path->slots[0]) {
1527                         path->slots[0]--;
1528                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1529                                               path->slots[0]);
1530                         if (key.objectid == bytenr &&
1531                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1532                             key.offset == num_bytes)
1533                                 ret = 0;
1534                 }
1535                 if (ret) {
1536                         key.objectid = bytenr;
1537                         key.type = BTRFS_EXTENT_ITEM_KEY;
1538                         key.offset = num_bytes;
1539                         btrfs_release_path(path);
1540                         goto again;
1541                 }
1542         }
1543
1544         if (ret && !insert) {
1545                 err = -ENOENT;
1546                 goto out;
1547         } else if (WARN_ON(ret)) {
1548                 err = -EIO;
1549                 goto out;
1550         }
1551
1552         leaf = path->nodes[0];
1553         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1554 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1555         if (item_size < sizeof(*ei)) {
1556                 if (!insert) {
1557                         err = -ENOENT;
1558                         goto out;
1559                 }
1560                 ret = convert_extent_item_v0(trans, root, path, owner,
1561                                              extra_size);
1562                 if (ret < 0) {
1563                         err = ret;
1564                         goto out;
1565                 }
1566                 leaf = path->nodes[0];
1567                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1568         }
1569 #endif
1570         BUG_ON(item_size < sizeof(*ei));
1571
1572         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1573         flags = btrfs_extent_flags(leaf, ei);
1574
1575         ptr = (unsigned long)(ei + 1);
1576         end = (unsigned long)ei + item_size;
1577
1578         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1579                 ptr += sizeof(struct btrfs_tree_block_info);
1580                 BUG_ON(ptr > end);
1581         }
1582
1583         err = -ENOENT;
1584         while (1) {
1585                 if (ptr >= end) {
1586                         WARN_ON(ptr > end);
1587                         break;
1588                 }
1589                 iref = (struct btrfs_extent_inline_ref *)ptr;
1590                 type = btrfs_extent_inline_ref_type(leaf, iref);
1591                 if (want < type)
1592                         break;
1593                 if (want > type) {
1594                         ptr += btrfs_extent_inline_ref_size(type);
1595                         continue;
1596                 }
1597
1598                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1599                         struct btrfs_extent_data_ref *dref;
1600                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1601                         if (match_extent_data_ref(leaf, dref, root_objectid,
1602                                                   owner, offset)) {
1603                                 err = 0;
1604                                 break;
1605                         }
1606                         if (hash_extent_data_ref_item(leaf, dref) <
1607                             hash_extent_data_ref(root_objectid, owner, offset))
1608                                 break;
1609                 } else {
1610                         u64 ref_offset;
1611                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1612                         if (parent > 0) {
1613                                 if (parent == ref_offset) {
1614                                         err = 0;
1615                                         break;
1616                                 }
1617                                 if (ref_offset < parent)
1618                                         break;
1619                         } else {
1620                                 if (root_objectid == ref_offset) {
1621                                         err = 0;
1622                                         break;
1623                                 }
1624                                 if (ref_offset < root_objectid)
1625                                         break;
1626                         }
1627                 }
1628                 ptr += btrfs_extent_inline_ref_size(type);
1629         }
1630         if (err == -ENOENT && insert) {
1631                 if (item_size + extra_size >=
1632                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1633                         err = -EAGAIN;
1634                         goto out;
1635                 }
1636                 /*
1637                  * To add new inline back ref, we have to make sure
1638                  * there is no corresponding back ref item.
1639                  * For simplicity, we just do not add new inline back
1640                  * ref if there is any kind of item for this block
1641                  */
1642                 if (find_next_key(path, 0, &key) == 0 &&
1643                     key.objectid == bytenr &&
1644                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1645                         err = -EAGAIN;
1646                         goto out;
1647                 }
1648         }
1649         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1650 out:
1651         if (insert) {
1652                 path->keep_locks = 0;
1653                 btrfs_unlock_up_safe(path, 1);
1654         }
1655         return err;
1656 }
1657
1658 /*
1659  * helper to add new inline back ref
1660  */
1661 static noinline_for_stack
1662 void setup_inline_extent_backref(struct btrfs_root *root,
1663                                  struct btrfs_path *path,
1664                                  struct btrfs_extent_inline_ref *iref,
1665                                  u64 parent, u64 root_objectid,
1666                                  u64 owner, u64 offset, int refs_to_add,
1667                                  struct btrfs_delayed_extent_op *extent_op)
1668 {
1669         struct extent_buffer *leaf;
1670         struct btrfs_extent_item *ei;
1671         unsigned long ptr;
1672         unsigned long end;
1673         unsigned long item_offset;
1674         u64 refs;
1675         int size;
1676         int type;
1677
1678         leaf = path->nodes[0];
1679         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1680         item_offset = (unsigned long)iref - (unsigned long)ei;
1681
1682         type = extent_ref_type(parent, owner);
1683         size = btrfs_extent_inline_ref_size(type);
1684
1685         btrfs_extend_item(root, path, size);
1686
1687         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1688         refs = btrfs_extent_refs(leaf, ei);
1689         refs += refs_to_add;
1690         btrfs_set_extent_refs(leaf, ei, refs);
1691         if (extent_op)
1692                 __run_delayed_extent_op(extent_op, leaf, ei);
1693
1694         ptr = (unsigned long)ei + item_offset;
1695         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1696         if (ptr < end - size)
1697                 memmove_extent_buffer(leaf, ptr + size, ptr,
1698                                       end - size - ptr);
1699
1700         iref = (struct btrfs_extent_inline_ref *)ptr;
1701         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1702         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1703                 struct btrfs_extent_data_ref *dref;
1704                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1705                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1706                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1707                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1708                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1709         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1710                 struct btrfs_shared_data_ref *sref;
1711                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1712                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1713                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1714         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1715                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1716         } else {
1717                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1718         }
1719         btrfs_mark_buffer_dirty(leaf);
1720 }
1721
1722 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1723                                  struct btrfs_root *root,
1724                                  struct btrfs_path *path,
1725                                  struct btrfs_extent_inline_ref **ref_ret,
1726                                  u64 bytenr, u64 num_bytes, u64 parent,
1727                                  u64 root_objectid, u64 owner, u64 offset)
1728 {
1729         int ret;
1730
1731         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1732                                            bytenr, num_bytes, parent,
1733                                            root_objectid, owner, offset, 0);
1734         if (ret != -ENOENT)
1735                 return ret;
1736
1737         btrfs_release_path(path);
1738         *ref_ret = NULL;
1739
1740         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1741                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1742                                             root_objectid);
1743         } else {
1744                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1745                                              root_objectid, owner, offset);
1746         }
1747         return ret;
1748 }
1749
1750 /*
1751  * helper to update/remove inline back ref
1752  */
1753 static noinline_for_stack
1754 void update_inline_extent_backref(struct btrfs_root *root,
1755                                   struct btrfs_path *path,
1756                                   struct btrfs_extent_inline_ref *iref,
1757                                   int refs_to_mod,
1758                                   struct btrfs_delayed_extent_op *extent_op,
1759                                   int *last_ref)
1760 {
1761         struct extent_buffer *leaf;
1762         struct btrfs_extent_item *ei;
1763         struct btrfs_extent_data_ref *dref = NULL;
1764         struct btrfs_shared_data_ref *sref = NULL;
1765         unsigned long ptr;
1766         unsigned long end;
1767         u32 item_size;
1768         int size;
1769         int type;
1770         u64 refs;
1771
1772         leaf = path->nodes[0];
1773         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1774         refs = btrfs_extent_refs(leaf, ei);
1775         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1776         refs += refs_to_mod;
1777         btrfs_set_extent_refs(leaf, ei, refs);
1778         if (extent_op)
1779                 __run_delayed_extent_op(extent_op, leaf, ei);
1780
1781         type = btrfs_extent_inline_ref_type(leaf, iref);
1782
1783         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1784                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1785                 refs = btrfs_extent_data_ref_count(leaf, dref);
1786         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1787                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1788                 refs = btrfs_shared_data_ref_count(leaf, sref);
1789         } else {
1790                 refs = 1;
1791                 BUG_ON(refs_to_mod != -1);
1792         }
1793
1794         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1795         refs += refs_to_mod;
1796
1797         if (refs > 0) {
1798                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1799                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1800                 else
1801                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1802         } else {
1803                 *last_ref = 1;
1804                 size =  btrfs_extent_inline_ref_size(type);
1805                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1806                 ptr = (unsigned long)iref;
1807                 end = (unsigned long)ei + item_size;
1808                 if (ptr + size < end)
1809                         memmove_extent_buffer(leaf, ptr, ptr + size,
1810                                               end - ptr - size);
1811                 item_size -= size;
1812                 btrfs_truncate_item(root, path, item_size, 1);
1813         }
1814         btrfs_mark_buffer_dirty(leaf);
1815 }
1816
1817 static noinline_for_stack
1818 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1819                                  struct btrfs_root *root,
1820                                  struct btrfs_path *path,
1821                                  u64 bytenr, u64 num_bytes, u64 parent,
1822                                  u64 root_objectid, u64 owner,
1823                                  u64 offset, int refs_to_add,
1824                                  struct btrfs_delayed_extent_op *extent_op)
1825 {
1826         struct btrfs_extent_inline_ref *iref;
1827         int ret;
1828
1829         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1830                                            bytenr, num_bytes, parent,
1831                                            root_objectid, owner, offset, 1);
1832         if (ret == 0) {
1833                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1834                 update_inline_extent_backref(root, path, iref,
1835                                              refs_to_add, extent_op, NULL);
1836         } else if (ret == -ENOENT) {
1837                 setup_inline_extent_backref(root, path, iref, parent,
1838                                             root_objectid, owner, offset,
1839                                             refs_to_add, extent_op);
1840                 ret = 0;
1841         }
1842         return ret;
1843 }
1844
1845 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1846                                  struct btrfs_root *root,
1847                                  struct btrfs_path *path,
1848                                  u64 bytenr, u64 parent, u64 root_objectid,
1849                                  u64 owner, u64 offset, int refs_to_add)
1850 {
1851         int ret;
1852         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1853                 BUG_ON(refs_to_add != 1);
1854                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1855                                             parent, root_objectid);
1856         } else {
1857                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1858                                              parent, root_objectid,
1859                                              owner, offset, refs_to_add);
1860         }
1861         return ret;
1862 }
1863
1864 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1865                                  struct btrfs_root *root,
1866                                  struct btrfs_path *path,
1867                                  struct btrfs_extent_inline_ref *iref,
1868                                  int refs_to_drop, int is_data, int *last_ref)
1869 {
1870         int ret = 0;
1871
1872         BUG_ON(!is_data && refs_to_drop != 1);
1873         if (iref) {
1874                 update_inline_extent_backref(root, path, iref,
1875                                              -refs_to_drop, NULL, last_ref);
1876         } else if (is_data) {
1877                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1878                                              last_ref);
1879         } else {
1880                 *last_ref = 1;
1881                 ret = btrfs_del_item(trans, root, path);
1882         }
1883         return ret;
1884 }
1885
1886 static int btrfs_issue_discard(struct block_device *bdev,
1887                                 u64 start, u64 len)
1888 {
1889         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1890 }
1891
1892 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1893                          u64 num_bytes, u64 *actual_bytes)
1894 {
1895         int ret;
1896         u64 discarded_bytes = 0;
1897         struct btrfs_bio *bbio = NULL;
1898
1899
1900         /* Tell the block device(s) that the sectors can be discarded */
1901         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1902                               bytenr, &num_bytes, &bbio, 0);
1903         /* Error condition is -ENOMEM */
1904         if (!ret) {
1905                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1906                 int i;
1907
1908
1909                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1910                         if (!stripe->dev->can_discard)
1911                                 continue;
1912
1913                         ret = btrfs_issue_discard(stripe->dev->bdev,
1914                                                   stripe->physical,
1915                                                   stripe->length);
1916                         if (!ret)
1917                                 discarded_bytes += stripe->length;
1918                         else if (ret != -EOPNOTSUPP)
1919                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1920
1921                         /*
1922                          * Just in case we get back EOPNOTSUPP for some reason,
1923                          * just ignore the return value so we don't screw up
1924                          * people calling discard_extent.
1925                          */
1926                         ret = 0;
1927                 }
1928                 btrfs_put_bbio(bbio);
1929         }
1930
1931         if (actual_bytes)
1932                 *actual_bytes = discarded_bytes;
1933
1934
1935         if (ret == -EOPNOTSUPP)
1936                 ret = 0;
1937         return ret;
1938 }
1939
1940 /* Can return -ENOMEM */
1941 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1942                          struct btrfs_root *root,
1943                          u64 bytenr, u64 num_bytes, u64 parent,
1944                          u64 root_objectid, u64 owner, u64 offset,
1945                          int no_quota)
1946 {
1947         int ret;
1948         struct btrfs_fs_info *fs_info = root->fs_info;
1949
1950         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1951                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1952
1953         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1954                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1955                                         num_bytes,
1956                                         parent, root_objectid, (int)owner,
1957                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
1958         } else {
1959                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1960                                         num_bytes,
1961                                         parent, root_objectid, owner, offset,
1962                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
1963         }
1964         return ret;
1965 }
1966
1967 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1968                                   struct btrfs_root *root,
1969                                   struct btrfs_delayed_ref_node *node,
1970                                   u64 parent, u64 root_objectid,
1971                                   u64 owner, u64 offset, int refs_to_add,
1972                                   struct btrfs_delayed_extent_op *extent_op)
1973 {
1974         struct btrfs_fs_info *fs_info = root->fs_info;
1975         struct btrfs_path *path;
1976         struct extent_buffer *leaf;
1977         struct btrfs_extent_item *item;
1978         struct btrfs_key key;
1979         u64 bytenr = node->bytenr;
1980         u64 num_bytes = node->num_bytes;
1981         u64 refs;
1982         int ret;
1983         int no_quota = node->no_quota;
1984         enum btrfs_qgroup_operation_type type = BTRFS_QGROUP_OPER_ADD_EXCL;
1985
1986         path = btrfs_alloc_path();
1987         if (!path)
1988                 return -ENOMEM;
1989
1990         if (!is_fstree(root_objectid) || !root->fs_info->quota_enabled)
1991                 no_quota = 1;
1992
1993         path->reada = 1;
1994         path->leave_spinning = 1;
1995         /* this will setup the path even if it fails to insert the back ref */
1996         ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
1997                                            bytenr, num_bytes, parent,
1998                                            root_objectid, owner, offset,
1999                                            refs_to_add, extent_op);
2000         if ((ret < 0 && ret != -EAGAIN) || !ret)
2001                 goto out;
2002
2003         /*
2004          * Ok we had -EAGAIN which means we didn't have space to insert and
2005          * inline extent ref, so just update the reference count and add a
2006          * normal backref.
2007          */
2008         leaf = path->nodes[0];
2009         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2010         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2011         refs = btrfs_extent_refs(leaf, item);
2012         if (refs)
2013                 type = BTRFS_QGROUP_OPER_ADD_SHARED;
2014         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2015         if (extent_op)
2016                 __run_delayed_extent_op(extent_op, leaf, item);
2017
2018         btrfs_mark_buffer_dirty(leaf);
2019         btrfs_release_path(path);
2020
2021         path->reada = 1;
2022         path->leave_spinning = 1;
2023         /* now insert the actual backref */
2024         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2025                                     path, bytenr, parent, root_objectid,
2026                                     owner, offset, refs_to_add);
2027         if (ret)
2028                 btrfs_abort_transaction(trans, root, ret);
2029 out:
2030         btrfs_free_path(path);
2031         return ret;
2032 }
2033
2034 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2035                                 struct btrfs_root *root,
2036                                 struct btrfs_delayed_ref_node *node,
2037                                 struct btrfs_delayed_extent_op *extent_op,
2038                                 int insert_reserved)
2039 {
2040         int ret = 0;
2041         struct btrfs_delayed_data_ref *ref;
2042         struct btrfs_key ins;
2043         u64 parent = 0;
2044         u64 ref_root = 0;
2045         u64 flags = 0;
2046
2047         ins.objectid = node->bytenr;
2048         ins.offset = node->num_bytes;
2049         ins.type = BTRFS_EXTENT_ITEM_KEY;
2050
2051         ref = btrfs_delayed_node_to_data_ref(node);
2052         trace_run_delayed_data_ref(node, ref, node->action);
2053
2054         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2055                 parent = ref->parent;
2056         ref_root = ref->root;
2057
2058         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2059                 if (extent_op)
2060                         flags |= extent_op->flags_to_set;
2061                 ret = alloc_reserved_file_extent(trans, root,
2062                                                  parent, ref_root, flags,
2063                                                  ref->objectid, ref->offset,
2064                                                  &ins, node->ref_mod);
2065         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2066                 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2067                                              ref_root, ref->objectid,
2068                                              ref->offset, node->ref_mod,
2069                                              extent_op);
2070         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2071                 ret = __btrfs_free_extent(trans, root, node, parent,
2072                                           ref_root, ref->objectid,
2073                                           ref->offset, node->ref_mod,
2074                                           extent_op);
2075         } else {
2076                 BUG();
2077         }
2078         return ret;
2079 }
2080
2081 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2082                                     struct extent_buffer *leaf,
2083                                     struct btrfs_extent_item *ei)
2084 {
2085         u64 flags = btrfs_extent_flags(leaf, ei);
2086         if (extent_op->update_flags) {
2087                 flags |= extent_op->flags_to_set;
2088                 btrfs_set_extent_flags(leaf, ei, flags);
2089         }
2090
2091         if (extent_op->update_key) {
2092                 struct btrfs_tree_block_info *bi;
2093                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2094                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2095                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2096         }
2097 }
2098
2099 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2100                                  struct btrfs_root *root,
2101                                  struct btrfs_delayed_ref_node *node,
2102                                  struct btrfs_delayed_extent_op *extent_op)
2103 {
2104         struct btrfs_key key;
2105         struct btrfs_path *path;
2106         struct btrfs_extent_item *ei;
2107         struct extent_buffer *leaf;
2108         u32 item_size;
2109         int ret;
2110         int err = 0;
2111         int metadata = !extent_op->is_data;
2112
2113         if (trans->aborted)
2114                 return 0;
2115
2116         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2117                 metadata = 0;
2118
2119         path = btrfs_alloc_path();
2120         if (!path)
2121                 return -ENOMEM;
2122
2123         key.objectid = node->bytenr;
2124
2125         if (metadata) {
2126                 key.type = BTRFS_METADATA_ITEM_KEY;
2127                 key.offset = extent_op->level;
2128         } else {
2129                 key.type = BTRFS_EXTENT_ITEM_KEY;
2130                 key.offset = node->num_bytes;
2131         }
2132
2133 again:
2134         path->reada = 1;
2135         path->leave_spinning = 1;
2136         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2137                                 path, 0, 1);
2138         if (ret < 0) {
2139                 err = ret;
2140                 goto out;
2141         }
2142         if (ret > 0) {
2143                 if (metadata) {
2144                         if (path->slots[0] > 0) {
2145                                 path->slots[0]--;
2146                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2147                                                       path->slots[0]);
2148                                 if (key.objectid == node->bytenr &&
2149                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2150                                     key.offset == node->num_bytes)
2151                                         ret = 0;
2152                         }
2153                         if (ret > 0) {
2154                                 btrfs_release_path(path);
2155                                 metadata = 0;
2156
2157                                 key.objectid = node->bytenr;
2158                                 key.offset = node->num_bytes;
2159                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2160                                 goto again;
2161                         }
2162                 } else {
2163                         err = -EIO;
2164                         goto out;
2165                 }
2166         }
2167
2168         leaf = path->nodes[0];
2169         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2170 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2171         if (item_size < sizeof(*ei)) {
2172                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2173                                              path, (u64)-1, 0);
2174                 if (ret < 0) {
2175                         err = ret;
2176                         goto out;
2177                 }
2178                 leaf = path->nodes[0];
2179                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2180         }
2181 #endif
2182         BUG_ON(item_size < sizeof(*ei));
2183         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2184         __run_delayed_extent_op(extent_op, leaf, ei);
2185
2186         btrfs_mark_buffer_dirty(leaf);
2187 out:
2188         btrfs_free_path(path);
2189         return err;
2190 }
2191
2192 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2193                                 struct btrfs_root *root,
2194                                 struct btrfs_delayed_ref_node *node,
2195                                 struct btrfs_delayed_extent_op *extent_op,
2196                                 int insert_reserved)
2197 {
2198         int ret = 0;
2199         struct btrfs_delayed_tree_ref *ref;
2200         struct btrfs_key ins;
2201         u64 parent = 0;
2202         u64 ref_root = 0;
2203         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2204                                                  SKINNY_METADATA);
2205
2206         ref = btrfs_delayed_node_to_tree_ref(node);
2207         trace_run_delayed_tree_ref(node, ref, node->action);
2208
2209         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2210                 parent = ref->parent;
2211         ref_root = ref->root;
2212
2213         ins.objectid = node->bytenr;
2214         if (skinny_metadata) {
2215                 ins.offset = ref->level;
2216                 ins.type = BTRFS_METADATA_ITEM_KEY;
2217         } else {
2218                 ins.offset = node->num_bytes;
2219                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2220         }
2221
2222         BUG_ON(node->ref_mod != 1);
2223         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2224                 BUG_ON(!extent_op || !extent_op->update_flags);
2225                 ret = alloc_reserved_tree_block(trans, root,
2226                                                 parent, ref_root,
2227                                                 extent_op->flags_to_set,
2228                                                 &extent_op->key,
2229                                                 ref->level, &ins,
2230                                                 node->no_quota);
2231         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2232                 ret = __btrfs_inc_extent_ref(trans, root, node,
2233                                              parent, ref_root,
2234                                              ref->level, 0, 1,
2235                                              extent_op);
2236         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2237                 ret = __btrfs_free_extent(trans, root, node,
2238                                           parent, ref_root,
2239                                           ref->level, 0, 1, extent_op);
2240         } else {
2241                 BUG();
2242         }
2243         return ret;
2244 }
2245
2246 /* helper function to actually process a single delayed ref entry */
2247 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2248                                struct btrfs_root *root,
2249                                struct btrfs_delayed_ref_node *node,
2250                                struct btrfs_delayed_extent_op *extent_op,
2251                                int insert_reserved)
2252 {
2253         int ret = 0;
2254
2255         if (trans->aborted) {
2256                 if (insert_reserved)
2257                         btrfs_pin_extent(root, node->bytenr,
2258                                          node->num_bytes, 1);
2259                 return 0;
2260         }
2261
2262         if (btrfs_delayed_ref_is_head(node)) {
2263                 struct btrfs_delayed_ref_head *head;
2264                 /*
2265                  * we've hit the end of the chain and we were supposed
2266                  * to insert this extent into the tree.  But, it got
2267                  * deleted before we ever needed to insert it, so all
2268                  * we have to do is clean up the accounting
2269                  */
2270                 BUG_ON(extent_op);
2271                 head = btrfs_delayed_node_to_head(node);
2272                 trace_run_delayed_ref_head(node, head, node->action);
2273
2274                 if (insert_reserved) {
2275                         btrfs_pin_extent(root, node->bytenr,
2276                                          node->num_bytes, 1);
2277                         if (head->is_data) {
2278                                 ret = btrfs_del_csums(trans, root,
2279                                                       node->bytenr,
2280                                                       node->num_bytes);
2281                         }
2282                 }
2283                 return ret;
2284         }
2285
2286         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2287             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2288                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2289                                            insert_reserved);
2290         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2291                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2292                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2293                                            insert_reserved);
2294         else
2295                 BUG();
2296         return ret;
2297 }
2298
2299 static inline struct btrfs_delayed_ref_node *
2300 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2301 {
2302         if (list_empty(&head->ref_list))
2303                 return NULL;
2304
2305         return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2306                           list);
2307 }
2308
2309 /*
2310  * Returns 0 on success or if called with an already aborted transaction.
2311  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2312  */
2313 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2314                                              struct btrfs_root *root,
2315                                              unsigned long nr)
2316 {
2317         struct btrfs_delayed_ref_root *delayed_refs;
2318         struct btrfs_delayed_ref_node *ref;
2319         struct btrfs_delayed_ref_head *locked_ref = NULL;
2320         struct btrfs_delayed_extent_op *extent_op;
2321         struct btrfs_fs_info *fs_info = root->fs_info;
2322         ktime_t start = ktime_get();
2323         int ret;
2324         unsigned long count = 0;
2325         unsigned long actual_count = 0;
2326         int must_insert_reserved = 0;
2327
2328         delayed_refs = &trans->transaction->delayed_refs;
2329         while (1) {
2330                 if (!locked_ref) {
2331                         if (count >= nr)
2332                                 break;
2333
2334                         spin_lock(&delayed_refs->lock);
2335                         locked_ref = btrfs_select_ref_head(trans);
2336                         if (!locked_ref) {
2337                                 spin_unlock(&delayed_refs->lock);
2338                                 break;
2339                         }
2340
2341                         /* grab the lock that says we are going to process
2342                          * all the refs for this head */
2343                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2344                         spin_unlock(&delayed_refs->lock);
2345                         /*
2346                          * we may have dropped the spin lock to get the head
2347                          * mutex lock, and that might have given someone else
2348                          * time to free the head.  If that's true, it has been
2349                          * removed from our list and we can move on.
2350                          */
2351                         if (ret == -EAGAIN) {
2352                                 locked_ref = NULL;
2353                                 count++;
2354                                 continue;
2355                         }
2356                 }
2357
2358                 spin_lock(&locked_ref->lock);
2359
2360                 /*
2361                  * locked_ref is the head node, so we have to go one
2362                  * node back for any delayed ref updates
2363                  */
2364                 ref = select_delayed_ref(locked_ref);
2365
2366                 if (ref && ref->seq &&
2367                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2368                         spin_unlock(&locked_ref->lock);
2369                         btrfs_delayed_ref_unlock(locked_ref);
2370                         spin_lock(&delayed_refs->lock);
2371                         locked_ref->processing = 0;
2372                         delayed_refs->num_heads_ready++;
2373                         spin_unlock(&delayed_refs->lock);
2374                         locked_ref = NULL;
2375                         cond_resched();
2376                         count++;
2377                         continue;
2378                 }
2379
2380                 /*
2381                  * record the must insert reserved flag before we
2382                  * drop the spin lock.
2383                  */
2384                 must_insert_reserved = locked_ref->must_insert_reserved;
2385                 locked_ref->must_insert_reserved = 0;
2386
2387                 extent_op = locked_ref->extent_op;
2388                 locked_ref->extent_op = NULL;
2389
2390                 if (!ref) {
2391
2392
2393                         /* All delayed refs have been processed, Go ahead
2394                          * and send the head node to run_one_delayed_ref,
2395                          * so that any accounting fixes can happen
2396                          */
2397                         ref = &locked_ref->node;
2398
2399                         if (extent_op && must_insert_reserved) {
2400                                 btrfs_free_delayed_extent_op(extent_op);
2401                                 extent_op = NULL;
2402                         }
2403
2404                         if (extent_op) {
2405                                 spin_unlock(&locked_ref->lock);
2406                                 ret = run_delayed_extent_op(trans, root,
2407                                                             ref, extent_op);
2408                                 btrfs_free_delayed_extent_op(extent_op);
2409
2410                                 if (ret) {
2411                                         /*
2412                                          * Need to reset must_insert_reserved if
2413                                          * there was an error so the abort stuff
2414                                          * can cleanup the reserved space
2415                                          * properly.
2416                                          */
2417                                         if (must_insert_reserved)
2418                                                 locked_ref->must_insert_reserved = 1;
2419                                         locked_ref->processing = 0;
2420                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2421                                         btrfs_delayed_ref_unlock(locked_ref);
2422                                         return ret;
2423                                 }
2424                                 continue;
2425                         }
2426
2427                         /*
2428                          * Need to drop our head ref lock and re-aqcuire the
2429                          * delayed ref lock and then re-check to make sure
2430                          * nobody got added.
2431                          */
2432                         spin_unlock(&locked_ref->lock);
2433                         spin_lock(&delayed_refs->lock);
2434                         spin_lock(&locked_ref->lock);
2435                         if (!list_empty(&locked_ref->ref_list) ||
2436                             locked_ref->extent_op) {
2437                                 spin_unlock(&locked_ref->lock);
2438                                 spin_unlock(&delayed_refs->lock);
2439                                 continue;
2440                         }
2441                         ref->in_tree = 0;
2442                         delayed_refs->num_heads--;
2443                         rb_erase(&locked_ref->href_node,
2444                                  &delayed_refs->href_root);
2445                         spin_unlock(&delayed_refs->lock);
2446                 } else {
2447                         actual_count++;
2448                         ref->in_tree = 0;
2449                         list_del(&ref->list);
2450                 }
2451                 atomic_dec(&delayed_refs->num_entries);
2452
2453                 if (!btrfs_delayed_ref_is_head(ref)) {
2454                         /*
2455                          * when we play the delayed ref, also correct the
2456                          * ref_mod on head
2457                          */
2458                         switch (ref->action) {
2459                         case BTRFS_ADD_DELAYED_REF:
2460                         case BTRFS_ADD_DELAYED_EXTENT:
2461                                 locked_ref->node.ref_mod -= ref->ref_mod;
2462                                 break;
2463                         case BTRFS_DROP_DELAYED_REF:
2464                                 locked_ref->node.ref_mod += ref->ref_mod;
2465                                 break;
2466                         default:
2467                                 WARN_ON(1);
2468                         }
2469                 }
2470                 spin_unlock(&locked_ref->lock);
2471
2472                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2473                                           must_insert_reserved);
2474
2475                 btrfs_free_delayed_extent_op(extent_op);
2476                 if (ret) {
2477                         locked_ref->processing = 0;
2478                         btrfs_delayed_ref_unlock(locked_ref);
2479                         btrfs_put_delayed_ref(ref);
2480                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2481                         return ret;
2482                 }
2483
2484                 /*
2485                  * If this node is a head, that means all the refs in this head
2486                  * have been dealt with, and we will pick the next head to deal
2487                  * with, so we must unlock the head and drop it from the cluster
2488                  * list before we release it.
2489                  */
2490                 if (btrfs_delayed_ref_is_head(ref)) {
2491                         if (locked_ref->is_data &&
2492                             locked_ref->total_ref_mod < 0) {
2493                                 spin_lock(&delayed_refs->lock);
2494                                 delayed_refs->pending_csums -= ref->num_bytes;
2495                                 spin_unlock(&delayed_refs->lock);
2496                         }
2497                         btrfs_delayed_ref_unlock(locked_ref);
2498                         locked_ref = NULL;
2499                 }
2500                 btrfs_put_delayed_ref(ref);
2501                 count++;
2502                 cond_resched();
2503         }
2504
2505         /*
2506          * We don't want to include ref heads since we can have empty ref heads
2507          * and those will drastically skew our runtime down since we just do
2508          * accounting, no actual extent tree updates.
2509          */
2510         if (actual_count > 0) {
2511                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2512                 u64 avg;
2513
2514                 /*
2515                  * We weigh the current average higher than our current runtime
2516                  * to avoid large swings in the average.
2517                  */
2518                 spin_lock(&delayed_refs->lock);
2519                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2520                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2521                 spin_unlock(&delayed_refs->lock);
2522         }
2523         return 0;
2524 }
2525
2526 #ifdef SCRAMBLE_DELAYED_REFS
2527 /*
2528  * Normally delayed refs get processed in ascending bytenr order. This
2529  * correlates in most cases to the order added. To expose dependencies on this
2530  * order, we start to process the tree in the middle instead of the beginning
2531  */
2532 static u64 find_middle(struct rb_root *root)
2533 {
2534         struct rb_node *n = root->rb_node;
2535         struct btrfs_delayed_ref_node *entry;
2536         int alt = 1;
2537         u64 middle;
2538         u64 first = 0, last = 0;
2539
2540         n = rb_first(root);
2541         if (n) {
2542                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2543                 first = entry->bytenr;
2544         }
2545         n = rb_last(root);
2546         if (n) {
2547                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2548                 last = entry->bytenr;
2549         }
2550         n = root->rb_node;
2551
2552         while (n) {
2553                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2554                 WARN_ON(!entry->in_tree);
2555
2556                 middle = entry->bytenr;
2557
2558                 if (alt)
2559                         n = n->rb_left;
2560                 else
2561                         n = n->rb_right;
2562
2563                 alt = 1 - alt;
2564         }
2565         return middle;
2566 }
2567 #endif
2568
2569 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2570 {
2571         u64 num_bytes;
2572
2573         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2574                              sizeof(struct btrfs_extent_inline_ref));
2575         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2576                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2577
2578         /*
2579          * We don't ever fill up leaves all the way so multiply by 2 just to be
2580          * closer to what we're really going to want to ouse.
2581          */
2582         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2583 }
2584
2585 /*
2586  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2587  * would require to store the csums for that many bytes.
2588  */
2589 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2590 {
2591         u64 csum_size;
2592         u64 num_csums_per_leaf;
2593         u64 num_csums;
2594
2595         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
2596         num_csums_per_leaf = div64_u64(csum_size,
2597                         (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2598         num_csums = div64_u64(csum_bytes, root->sectorsize);
2599         num_csums += num_csums_per_leaf - 1;
2600         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2601         return num_csums;
2602 }
2603
2604 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2605                                        struct btrfs_root *root)
2606 {
2607         struct btrfs_block_rsv *global_rsv;
2608         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2609         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2610         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2611         u64 num_bytes, num_dirty_bgs_bytes;
2612         int ret = 0;
2613
2614         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2615         num_heads = heads_to_leaves(root, num_heads);
2616         if (num_heads > 1)
2617                 num_bytes += (num_heads - 1) * root->nodesize;
2618         num_bytes <<= 1;
2619         num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2620         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2621                                                              num_dirty_bgs);
2622         global_rsv = &root->fs_info->global_block_rsv;
2623
2624         /*
2625          * If we can't allocate any more chunks lets make sure we have _lots_ of
2626          * wiggle room since running delayed refs can create more delayed refs.
2627          */
2628         if (global_rsv->space_info->full) {
2629                 num_dirty_bgs_bytes <<= 1;
2630                 num_bytes <<= 1;
2631         }
2632
2633         spin_lock(&global_rsv->lock);
2634         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2635                 ret = 1;
2636         spin_unlock(&global_rsv->lock);
2637         return ret;
2638 }
2639
2640 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2641                                        struct btrfs_root *root)
2642 {
2643         struct btrfs_fs_info *fs_info = root->fs_info;
2644         u64 num_entries =
2645                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2646         u64 avg_runtime;
2647         u64 val;
2648
2649         smp_mb();
2650         avg_runtime = fs_info->avg_delayed_ref_runtime;
2651         val = num_entries * avg_runtime;
2652         if (num_entries * avg_runtime >= NSEC_PER_SEC)
2653                 return 1;
2654         if (val >= NSEC_PER_SEC / 2)
2655                 return 2;
2656
2657         return btrfs_check_space_for_delayed_refs(trans, root);
2658 }
2659
2660 struct async_delayed_refs {
2661         struct btrfs_root *root;
2662         int count;
2663         int error;
2664         int sync;
2665         struct completion wait;
2666         struct btrfs_work work;
2667 };
2668
2669 static void delayed_ref_async_start(struct btrfs_work *work)
2670 {
2671         struct async_delayed_refs *async;
2672         struct btrfs_trans_handle *trans;
2673         int ret;
2674
2675         async = container_of(work, struct async_delayed_refs, work);
2676
2677         trans = btrfs_join_transaction(async->root);
2678         if (IS_ERR(trans)) {
2679                 async->error = PTR_ERR(trans);
2680                 goto done;
2681         }
2682
2683         /*
2684          * trans->sync means that when we call end_transaciton, we won't
2685          * wait on delayed refs
2686          */
2687         trans->sync = true;
2688         ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2689         if (ret)
2690                 async->error = ret;
2691
2692         ret = btrfs_end_transaction(trans, async->root);
2693         if (ret && !async->error)
2694                 async->error = ret;
2695 done:
2696         if (async->sync)
2697                 complete(&async->wait);
2698         else
2699                 kfree(async);
2700 }
2701
2702 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2703                                  unsigned long count, int wait)
2704 {
2705         struct async_delayed_refs *async;
2706         int ret;
2707
2708         async = kmalloc(sizeof(*async), GFP_NOFS);
2709         if (!async)
2710                 return -ENOMEM;
2711
2712         async->root = root->fs_info->tree_root;
2713         async->count = count;
2714         async->error = 0;
2715         if (wait)
2716                 async->sync = 1;
2717         else
2718                 async->sync = 0;
2719         init_completion(&async->wait);
2720
2721         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2722                         delayed_ref_async_start, NULL, NULL);
2723
2724         btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2725
2726         if (wait) {
2727                 wait_for_completion(&async->wait);
2728                 ret = async->error;
2729                 kfree(async);
2730                 return ret;
2731         }
2732         return 0;
2733 }
2734
2735 /*
2736  * this starts processing the delayed reference count updates and
2737  * extent insertions we have queued up so far.  count can be
2738  * 0, which means to process everything in the tree at the start
2739  * of the run (but not newly added entries), or it can be some target
2740  * number you'd like to process.
2741  *
2742  * Returns 0 on success or if called with an aborted transaction
2743  * Returns <0 on error and aborts the transaction
2744  */
2745 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2746                            struct btrfs_root *root, unsigned long count)
2747 {
2748         struct rb_node *node;
2749         struct btrfs_delayed_ref_root *delayed_refs;
2750         struct btrfs_delayed_ref_head *head;
2751         int ret;
2752         int run_all = count == (unsigned long)-1;
2753
2754         /* We'll clean this up in btrfs_cleanup_transaction */
2755         if (trans->aborted)
2756                 return 0;
2757
2758         if (root == root->fs_info->extent_root)
2759                 root = root->fs_info->tree_root;
2760
2761         delayed_refs = &trans->transaction->delayed_refs;
2762         if (count == 0)
2763                 count = atomic_read(&delayed_refs->num_entries) * 2;
2764
2765 again:
2766 #ifdef SCRAMBLE_DELAYED_REFS
2767         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2768 #endif
2769         ret = __btrfs_run_delayed_refs(trans, root, count);
2770         if (ret < 0) {
2771                 btrfs_abort_transaction(trans, root, ret);
2772                 return ret;
2773         }
2774
2775         if (run_all) {
2776                 if (!list_empty(&trans->new_bgs))
2777                         btrfs_create_pending_block_groups(trans, root);
2778
2779                 spin_lock(&delayed_refs->lock);
2780                 node = rb_first(&delayed_refs->href_root);
2781                 if (!node) {
2782                         spin_unlock(&delayed_refs->lock);
2783                         goto out;
2784                 }
2785                 count = (unsigned long)-1;
2786
2787                 while (node) {
2788                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2789                                         href_node);
2790                         if (btrfs_delayed_ref_is_head(&head->node)) {
2791                                 struct btrfs_delayed_ref_node *ref;
2792
2793                                 ref = &head->node;
2794                                 atomic_inc(&ref->refs);
2795
2796                                 spin_unlock(&delayed_refs->lock);
2797                                 /*
2798                                  * Mutex was contended, block until it's
2799                                  * released and try again
2800                                  */
2801                                 mutex_lock(&head->mutex);
2802                                 mutex_unlock(&head->mutex);
2803
2804                                 btrfs_put_delayed_ref(ref);
2805                                 cond_resched();
2806                                 goto again;
2807                         } else {
2808                                 WARN_ON(1);
2809                         }
2810                         node = rb_next(node);
2811                 }
2812                 spin_unlock(&delayed_refs->lock);
2813                 cond_resched();
2814                 goto again;
2815         }
2816 out:
2817         assert_qgroups_uptodate(trans);
2818         return 0;
2819 }
2820
2821 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2822                                 struct btrfs_root *root,
2823                                 u64 bytenr, u64 num_bytes, u64 flags,
2824                                 int level, int is_data)
2825 {
2826         struct btrfs_delayed_extent_op *extent_op;
2827         int ret;
2828
2829         extent_op = btrfs_alloc_delayed_extent_op();
2830         if (!extent_op)
2831                 return -ENOMEM;
2832
2833         extent_op->flags_to_set = flags;
2834         extent_op->update_flags = 1;
2835         extent_op->update_key = 0;
2836         extent_op->is_data = is_data ? 1 : 0;
2837         extent_op->level = level;
2838
2839         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2840                                           num_bytes, extent_op);
2841         if (ret)
2842                 btrfs_free_delayed_extent_op(extent_op);
2843         return ret;
2844 }
2845
2846 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2847                                       struct btrfs_root *root,
2848                                       struct btrfs_path *path,
2849                                       u64 objectid, u64 offset, u64 bytenr)
2850 {
2851         struct btrfs_delayed_ref_head *head;
2852         struct btrfs_delayed_ref_node *ref;
2853         struct btrfs_delayed_data_ref *data_ref;
2854         struct btrfs_delayed_ref_root *delayed_refs;
2855         int ret = 0;
2856
2857         delayed_refs = &trans->transaction->delayed_refs;
2858         spin_lock(&delayed_refs->lock);
2859         head = btrfs_find_delayed_ref_head(trans, bytenr);
2860         if (!head) {
2861                 spin_unlock(&delayed_refs->lock);
2862                 return 0;
2863         }
2864
2865         if (!mutex_trylock(&head->mutex)) {
2866                 atomic_inc(&head->node.refs);
2867                 spin_unlock(&delayed_refs->lock);
2868
2869                 btrfs_release_path(path);
2870
2871                 /*
2872                  * Mutex was contended, block until it's released and let
2873                  * caller try again
2874                  */
2875                 mutex_lock(&head->mutex);
2876                 mutex_unlock(&head->mutex);
2877                 btrfs_put_delayed_ref(&head->node);
2878                 return -EAGAIN;
2879         }
2880         spin_unlock(&delayed_refs->lock);
2881
2882         spin_lock(&head->lock);
2883         list_for_each_entry(ref, &head->ref_list, list) {
2884                 /* If it's a shared ref we know a cross reference exists */
2885                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2886                         ret = 1;
2887                         break;
2888                 }
2889
2890                 data_ref = btrfs_delayed_node_to_data_ref(ref);
2891
2892                 /*
2893                  * If our ref doesn't match the one we're currently looking at
2894                  * then we have a cross reference.
2895                  */
2896                 if (data_ref->root != root->root_key.objectid ||
2897                     data_ref->objectid != objectid ||
2898                     data_ref->offset != offset) {
2899                         ret = 1;
2900                         break;
2901                 }
2902         }
2903         spin_unlock(&head->lock);
2904         mutex_unlock(&head->mutex);
2905         return ret;
2906 }
2907
2908 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2909                                         struct btrfs_root *root,
2910                                         struct btrfs_path *path,
2911                                         u64 objectid, u64 offset, u64 bytenr)
2912 {
2913         struct btrfs_root *extent_root = root->fs_info->extent_root;
2914         struct extent_buffer *leaf;
2915         struct btrfs_extent_data_ref *ref;
2916         struct btrfs_extent_inline_ref *iref;
2917         struct btrfs_extent_item *ei;
2918         struct btrfs_key key;
2919         u32 item_size;
2920         int ret;
2921
2922         key.objectid = bytenr;
2923         key.offset = (u64)-1;
2924         key.type = BTRFS_EXTENT_ITEM_KEY;
2925
2926         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2927         if (ret < 0)
2928                 goto out;
2929         BUG_ON(ret == 0); /* Corruption */
2930
2931         ret = -ENOENT;
2932         if (path->slots[0] == 0)
2933                 goto out;
2934
2935         path->slots[0]--;
2936         leaf = path->nodes[0];
2937         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2938
2939         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2940                 goto out;
2941
2942         ret = 1;
2943         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2944 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2945         if (item_size < sizeof(*ei)) {
2946                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2947                 goto out;
2948         }
2949 #endif
2950         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2951
2952         if (item_size != sizeof(*ei) +
2953             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2954                 goto out;
2955
2956         if (btrfs_extent_generation(leaf, ei) <=
2957             btrfs_root_last_snapshot(&root->root_item))
2958                 goto out;
2959
2960         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2961         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2962             BTRFS_EXTENT_DATA_REF_KEY)
2963                 goto out;
2964
2965         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2966         if (btrfs_extent_refs(leaf, ei) !=
2967             btrfs_extent_data_ref_count(leaf, ref) ||
2968             btrfs_extent_data_ref_root(leaf, ref) !=
2969             root->root_key.objectid ||
2970             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2971             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2972                 goto out;
2973
2974         ret = 0;
2975 out:
2976         return ret;
2977 }
2978
2979 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2980                           struct btrfs_root *root,
2981                           u64 objectid, u64 offset, u64 bytenr)
2982 {
2983         struct btrfs_path *path;
2984         int ret;
2985         int ret2;
2986
2987         path = btrfs_alloc_path();
2988         if (!path)
2989                 return -ENOENT;
2990
2991         do {
2992                 ret = check_committed_ref(trans, root, path, objectid,
2993                                           offset, bytenr);
2994                 if (ret && ret != -ENOENT)
2995                         goto out;
2996
2997                 ret2 = check_delayed_ref(trans, root, path, objectid,
2998                                          offset, bytenr);
2999         } while (ret2 == -EAGAIN);
3000
3001         if (ret2 && ret2 != -ENOENT) {
3002                 ret = ret2;
3003                 goto out;
3004         }
3005
3006         if (ret != -ENOENT || ret2 != -ENOENT)
3007                 ret = 0;
3008 out:
3009         btrfs_free_path(path);
3010         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3011                 WARN_ON(ret > 0);
3012         return ret;
3013 }
3014
3015 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3016                            struct btrfs_root *root,
3017                            struct extent_buffer *buf,
3018                            int full_backref, int inc)
3019 {
3020         u64 bytenr;
3021         u64 num_bytes;
3022         u64 parent;
3023         u64 ref_root;
3024         u32 nritems;
3025         struct btrfs_key key;
3026         struct btrfs_file_extent_item *fi;
3027         int i;
3028         int level;
3029         int ret = 0;
3030         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3031                             u64, u64, u64, u64, u64, u64, int);
3032
3033
3034         if (btrfs_test_is_dummy_root(root))
3035                 return 0;
3036
3037         ref_root = btrfs_header_owner(buf);
3038         nritems = btrfs_header_nritems(buf);
3039         level = btrfs_header_level(buf);
3040
3041         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3042                 return 0;
3043
3044         if (inc)
3045                 process_func = btrfs_inc_extent_ref;
3046         else
3047                 process_func = btrfs_free_extent;
3048
3049         if (full_backref)
3050                 parent = buf->start;
3051         else
3052                 parent = 0;
3053
3054         for (i = 0; i < nritems; i++) {
3055                 if (level == 0) {
3056                         btrfs_item_key_to_cpu(buf, &key, i);
3057                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3058                                 continue;
3059                         fi = btrfs_item_ptr(buf, i,
3060                                             struct btrfs_file_extent_item);
3061                         if (btrfs_file_extent_type(buf, fi) ==
3062                             BTRFS_FILE_EXTENT_INLINE)
3063                                 continue;
3064                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3065                         if (bytenr == 0)
3066                                 continue;
3067
3068                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3069                         key.offset -= btrfs_file_extent_offset(buf, fi);
3070                         ret = process_func(trans, root, bytenr, num_bytes,
3071                                            parent, ref_root, key.objectid,
3072                                            key.offset, 1);
3073                         if (ret)
3074                                 goto fail;
3075                 } else {
3076                         bytenr = btrfs_node_blockptr(buf, i);
3077                         num_bytes = root->nodesize;
3078                         ret = process_func(trans, root, bytenr, num_bytes,
3079                                            parent, ref_root, level - 1, 0,
3080                                            1);
3081                         if (ret)
3082                                 goto fail;
3083                 }
3084         }
3085         return 0;
3086 fail:
3087         return ret;
3088 }
3089
3090 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3091                   struct extent_buffer *buf, int full_backref)
3092 {
3093         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3094 }
3095
3096 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3097                   struct extent_buffer *buf, int full_backref)
3098 {
3099         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3100 }
3101
3102 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3103                                  struct btrfs_root *root,
3104                                  struct btrfs_path *path,
3105                                  struct btrfs_block_group_cache *cache)
3106 {
3107         int ret;
3108         struct btrfs_root *extent_root = root->fs_info->extent_root;
3109         unsigned long bi;
3110         struct extent_buffer *leaf;
3111
3112         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3113         if (ret) {
3114                 if (ret > 0)
3115                         ret = -ENOENT;
3116                 goto fail;
3117         }
3118
3119         leaf = path->nodes[0];
3120         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3121         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3122         btrfs_mark_buffer_dirty(leaf);
3123 fail:
3124         btrfs_release_path(path);
3125         return ret;
3126
3127 }
3128
3129 static struct btrfs_block_group_cache *
3130 next_block_group(struct btrfs_root *root,
3131                  struct btrfs_block_group_cache *cache)
3132 {
3133         struct rb_node *node;
3134
3135         spin_lock(&root->fs_info->block_group_cache_lock);
3136
3137         /* If our block group was removed, we need a full search. */
3138         if (RB_EMPTY_NODE(&cache->cache_node)) {
3139                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3140
3141                 spin_unlock(&root->fs_info->block_group_cache_lock);
3142                 btrfs_put_block_group(cache);
3143                 cache = btrfs_lookup_first_block_group(root->fs_info,
3144                                                        next_bytenr);
3145                 return cache;
3146         }
3147         node = rb_next(&cache->cache_node);
3148         btrfs_put_block_group(cache);
3149         if (node) {
3150                 cache = rb_entry(node, struct btrfs_block_group_cache,
3151                                  cache_node);
3152                 btrfs_get_block_group(cache);
3153         } else
3154                 cache = NULL;
3155         spin_unlock(&root->fs_info->block_group_cache_lock);
3156         return cache;
3157 }
3158
3159 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3160                             struct btrfs_trans_handle *trans,
3161                             struct btrfs_path *path)
3162 {
3163         struct btrfs_root *root = block_group->fs_info->tree_root;
3164         struct inode *inode = NULL;
3165         u64 alloc_hint = 0;
3166         int dcs = BTRFS_DC_ERROR;
3167         u64 num_pages = 0;
3168         int retries = 0;
3169         int ret = 0;
3170
3171         /*
3172          * If this block group is smaller than 100 megs don't bother caching the
3173          * block group.
3174          */
3175         if (block_group->key.offset < (100 * 1024 * 1024)) {
3176                 spin_lock(&block_group->lock);
3177                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3178                 spin_unlock(&block_group->lock);
3179                 return 0;
3180         }
3181
3182         if (trans->aborted)
3183                 return 0;
3184 again:
3185         inode = lookup_free_space_inode(root, block_group, path);
3186         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3187                 ret = PTR_ERR(inode);
3188                 btrfs_release_path(path);
3189                 goto out;
3190         }
3191
3192         if (IS_ERR(inode)) {
3193                 BUG_ON(retries);
3194                 retries++;
3195
3196                 if (block_group->ro)
3197                         goto out_free;
3198
3199                 ret = create_free_space_inode(root, trans, block_group, path);
3200                 if (ret)
3201                         goto out_free;
3202                 goto again;
3203         }
3204
3205         /* We've already setup this transaction, go ahead and exit */
3206         if (block_group->cache_generation == trans->transid &&
3207             i_size_read(inode)) {
3208                 dcs = BTRFS_DC_SETUP;
3209                 goto out_put;
3210         }
3211
3212         /*
3213          * We want to set the generation to 0, that way if anything goes wrong
3214          * from here on out we know not to trust this cache when we load up next
3215          * time.
3216          */
3217         BTRFS_I(inode)->generation = 0;
3218         ret = btrfs_update_inode(trans, root, inode);
3219         if (ret) {
3220                 /*
3221                  * So theoretically we could recover from this, simply set the
3222                  * super cache generation to 0 so we know to invalidate the
3223                  * cache, but then we'd have to keep track of the block groups
3224                  * that fail this way so we know we _have_ to reset this cache
3225                  * before the next commit or risk reading stale cache.  So to
3226                  * limit our exposure to horrible edge cases lets just abort the
3227                  * transaction, this only happens in really bad situations
3228                  * anyway.
3229                  */
3230                 btrfs_abort_transaction(trans, root, ret);
3231                 goto out_put;
3232         }
3233         WARN_ON(ret);
3234
3235         if (i_size_read(inode) > 0) {
3236                 ret = btrfs_check_trunc_cache_free_space(root,
3237                                         &root->fs_info->global_block_rsv);
3238                 if (ret)
3239                         goto out_put;
3240
3241                 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3242                 if (ret)
3243                         goto out_put;
3244         }
3245
3246         spin_lock(&block_group->lock);
3247         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3248             !btrfs_test_opt(root, SPACE_CACHE)) {
3249                 /*
3250                  * don't bother trying to write stuff out _if_
3251                  * a) we're not cached,
3252                  * b) we're with nospace_cache mount option.
3253                  */
3254                 dcs = BTRFS_DC_WRITTEN;
3255                 spin_unlock(&block_group->lock);
3256                 goto out_put;
3257         }
3258         spin_unlock(&block_group->lock);
3259
3260         /*
3261          * Try to preallocate enough space based on how big the block group is.
3262          * Keep in mind this has to include any pinned space which could end up
3263          * taking up quite a bit since it's not folded into the other space
3264          * cache.
3265          */
3266         num_pages = div_u64(block_group->key.offset, 256 * 1024 * 1024);
3267         if (!num_pages)
3268                 num_pages = 1;
3269
3270         num_pages *= 16;
3271         num_pages *= PAGE_CACHE_SIZE;
3272
3273         ret = btrfs_check_data_free_space(inode, num_pages, num_pages);
3274         if (ret)
3275                 goto out_put;
3276
3277         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3278                                               num_pages, num_pages,
3279                                               &alloc_hint);
3280         if (!ret)
3281                 dcs = BTRFS_DC_SETUP;
3282         btrfs_free_reserved_data_space(inode, num_pages);
3283
3284 out_put:
3285         iput(inode);
3286 out_free:
3287         btrfs_release_path(path);
3288 out:
3289         spin_lock(&block_group->lock);
3290         if (!ret && dcs == BTRFS_DC_SETUP)
3291                 block_group->cache_generation = trans->transid;
3292         block_group->disk_cache_state = dcs;
3293         spin_unlock(&block_group->lock);
3294
3295         return ret;
3296 }
3297
3298 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3299                             struct btrfs_root *root)
3300 {
3301         struct btrfs_block_group_cache *cache, *tmp;
3302         struct btrfs_transaction *cur_trans = trans->transaction;
3303         struct btrfs_path *path;
3304
3305         if (list_empty(&cur_trans->dirty_bgs) ||
3306             !btrfs_test_opt(root, SPACE_CACHE))
3307                 return 0;
3308
3309         path = btrfs_alloc_path();
3310         if (!path)
3311                 return -ENOMEM;
3312
3313         /* Could add new block groups, use _safe just in case */
3314         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3315                                  dirty_list) {
3316                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3317                         cache_save_setup(cache, trans, path);
3318         }
3319
3320         btrfs_free_path(path);
3321         return 0;
3322 }
3323
3324 /*
3325  * transaction commit does final block group cache writeback during a
3326  * critical section where nothing is allowed to change the FS.  This is
3327  * required in order for the cache to actually match the block group,
3328  * but can introduce a lot of latency into the commit.
3329  *
3330  * So, btrfs_start_dirty_block_groups is here to kick off block group
3331  * cache IO.  There's a chance we'll have to redo some of it if the
3332  * block group changes again during the commit, but it greatly reduces
3333  * the commit latency by getting rid of the easy block groups while
3334  * we're still allowing others to join the commit.
3335  */
3336 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3337                                    struct btrfs_root *root)
3338 {
3339         struct btrfs_block_group_cache *cache;
3340         struct btrfs_transaction *cur_trans = trans->transaction;
3341         int ret = 0;
3342         int should_put;
3343         struct btrfs_path *path = NULL;
3344         LIST_HEAD(dirty);
3345         struct list_head *io = &cur_trans->io_bgs;
3346         int num_started = 0;
3347         int loops = 0;
3348
3349         spin_lock(&cur_trans->dirty_bgs_lock);
3350         if (list_empty(&cur_trans->dirty_bgs)) {
3351                 spin_unlock(&cur_trans->dirty_bgs_lock);
3352                 return 0;
3353         }
3354         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3355         spin_unlock(&cur_trans->dirty_bgs_lock);
3356
3357 again:
3358         /*
3359          * make sure all the block groups on our dirty list actually
3360          * exist
3361          */
3362         btrfs_create_pending_block_groups(trans, root);
3363
3364         if (!path) {
3365                 path = btrfs_alloc_path();
3366                 if (!path)
3367                         return -ENOMEM;
3368         }
3369
3370         /*
3371          * cache_write_mutex is here only to save us from balance or automatic
3372          * removal of empty block groups deleting this block group while we are
3373          * writing out the cache
3374          */
3375         mutex_lock(&trans->transaction->cache_write_mutex);
3376         while (!list_empty(&dirty)) {
3377                 cache = list_first_entry(&dirty,
3378                                          struct btrfs_block_group_cache,
3379                                          dirty_list);
3380                 /*
3381                  * this can happen if something re-dirties a block
3382                  * group that is already under IO.  Just wait for it to
3383                  * finish and then do it all again
3384                  */
3385                 if (!list_empty(&cache->io_list)) {
3386                         list_del_init(&cache->io_list);
3387                         btrfs_wait_cache_io(root, trans, cache,
3388                                             &cache->io_ctl, path,
3389                                             cache->key.objectid);
3390                         btrfs_put_block_group(cache);
3391                 }
3392
3393
3394                 /*
3395                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3396                  * if it should update the cache_state.  Don't delete
3397                  * until after we wait.
3398                  *
3399                  * Since we're not running in the commit critical section
3400                  * we need the dirty_bgs_lock to protect from update_block_group
3401                  */
3402                 spin_lock(&cur_trans->dirty_bgs_lock);
3403                 list_del_init(&cache->dirty_list);
3404                 spin_unlock(&cur_trans->dirty_bgs_lock);
3405
3406                 should_put = 1;
3407
3408                 cache_save_setup(cache, trans, path);
3409
3410                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3411                         cache->io_ctl.inode = NULL;
3412                         ret = btrfs_write_out_cache(root, trans, cache, path);
3413                         if (ret == 0 && cache->io_ctl.inode) {
3414                                 num_started++;
3415                                 should_put = 0;
3416
3417                                 /*
3418                                  * the cache_write_mutex is protecting
3419                                  * the io_list
3420                                  */
3421                                 list_add_tail(&cache->io_list, io);
3422                         } else {
3423                                 /*
3424                                  * if we failed to write the cache, the
3425                                  * generation will be bad and life goes on
3426                                  */
3427                                 ret = 0;
3428                         }
3429                 }
3430                 if (!ret) {
3431                         ret = write_one_cache_group(trans, root, path, cache);
3432                         /*
3433                          * Our block group might still be attached to the list
3434                          * of new block groups in the transaction handle of some
3435                          * other task (struct btrfs_trans_handle->new_bgs). This
3436                          * means its block group item isn't yet in the extent
3437                          * tree. If this happens ignore the error, as we will
3438                          * try again later in the critical section of the
3439                          * transaction commit.
3440                          */
3441                         if (ret == -ENOENT) {
3442                                 ret = 0;
3443                                 spin_lock(&cur_trans->dirty_bgs_lock);
3444                                 if (list_empty(&cache->dirty_list)) {
3445                                         list_add_tail(&cache->dirty_list,
3446                                                       &cur_trans->dirty_bgs);
3447                                         btrfs_get_block_group(cache);
3448                                 }
3449                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3450                         } else if (ret) {
3451                                 btrfs_abort_transaction(trans, root, ret);
3452                         }
3453                 }
3454
3455                 /* if its not on the io list, we need to put the block group */
3456                 if (should_put)
3457                         btrfs_put_block_group(cache);
3458
3459                 if (ret)
3460                         break;
3461
3462                 /*
3463                  * Avoid blocking other tasks for too long. It might even save
3464                  * us from writing caches for block groups that are going to be
3465                  * removed.
3466                  */
3467                 mutex_unlock(&trans->transaction->cache_write_mutex);
3468                 mutex_lock(&trans->transaction->cache_write_mutex);
3469         }
3470         mutex_unlock(&trans->transaction->cache_write_mutex);
3471
3472         /*
3473          * go through delayed refs for all the stuff we've just kicked off
3474          * and then loop back (just once)
3475          */
3476         ret = btrfs_run_delayed_refs(trans, root, 0);
3477         if (!ret && loops == 0) {
3478                 loops++;
3479                 spin_lock(&cur_trans->dirty_bgs_lock);
3480                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3481                 /*
3482                  * dirty_bgs_lock protects us from concurrent block group
3483                  * deletes too (not just cache_write_mutex).
3484                  */
3485                 if (!list_empty(&dirty)) {
3486                         spin_unlock(&cur_trans->dirty_bgs_lock);
3487                         goto again;
3488                 }
3489                 spin_unlock(&cur_trans->dirty_bgs_lock);
3490         }
3491
3492         btrfs_free_path(path);
3493         return ret;
3494 }
3495
3496 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3497                                    struct btrfs_root *root)
3498 {
3499         struct btrfs_block_group_cache *cache;
3500         struct btrfs_transaction *cur_trans = trans->transaction;
3501         int ret = 0;
3502         int should_put;
3503         struct btrfs_path *path;
3504         struct list_head *io = &cur_trans->io_bgs;
3505         int num_started = 0;
3506
3507         path = btrfs_alloc_path();
3508         if (!path)
3509                 return -ENOMEM;
3510
3511         /*
3512          * We don't need the lock here since we are protected by the transaction
3513          * commit.  We want to do the cache_save_setup first and then run the
3514          * delayed refs to make sure we have the best chance at doing this all
3515          * in one shot.
3516          */
3517         while (!list_empty(&cur_trans->dirty_bgs)) {
3518                 cache = list_first_entry(&cur_trans->dirty_bgs,
3519                                          struct btrfs_block_group_cache,
3520                                          dirty_list);
3521
3522                 /*
3523                  * this can happen if cache_save_setup re-dirties a block
3524                  * group that is already under IO.  Just wait for it to
3525                  * finish and then do it all again
3526                  */
3527                 if (!list_empty(&cache->io_list)) {
3528                         list_del_init(&cache->io_list);
3529                         btrfs_wait_cache_io(root, trans, cache,
3530                                             &cache->io_ctl, path,
3531                                             cache->key.objectid);
3532                         btrfs_put_block_group(cache);
3533                 }
3534
3535                 /*
3536                  * don't remove from the dirty list until after we've waited
3537                  * on any pending IO
3538                  */
3539                 list_del_init(&cache->dirty_list);
3540                 should_put = 1;
3541
3542                 cache_save_setup(cache, trans, path);
3543
3544                 if (!ret)
3545                         ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3546
3547                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3548                         cache->io_ctl.inode = NULL;
3549                         ret = btrfs_write_out_cache(root, trans, cache, path);
3550                         if (ret == 0 && cache->io_ctl.inode) {
3551                                 num_started++;
3552                                 should_put = 0;
3553                                 list_add_tail(&cache->io_list, io);
3554                         } else {
3555                                 /*
3556                                  * if we failed to write the cache, the
3557                                  * generation will be bad and life goes on
3558                                  */
3559                                 ret = 0;
3560                         }
3561                 }
3562                 if (!ret) {
3563                         ret = write_one_cache_group(trans, root, path, cache);
3564                         if (ret)
3565                                 btrfs_abort_transaction(trans, root, ret);
3566                 }
3567
3568                 /* if its not on the io list, we need to put the block group */
3569                 if (should_put)
3570                         btrfs_put_block_group(cache);
3571         }
3572
3573         while (!list_empty(io)) {
3574                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3575                                          io_list);
3576                 list_del_init(&cache->io_list);
3577                 btrfs_wait_cache_io(root, trans, cache,
3578                                     &cache->io_ctl, path, cache->key.objectid);
3579                 btrfs_put_block_group(cache);
3580         }
3581
3582         btrfs_free_path(path);
3583         return ret;
3584 }
3585
3586 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3587 {
3588         struct btrfs_block_group_cache *block_group;
3589         int readonly = 0;
3590
3591         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3592         if (!block_group || block_group->ro)
3593                 readonly = 1;
3594         if (block_group)
3595                 btrfs_put_block_group(block_group);
3596         return readonly;
3597 }
3598
3599 static const char *alloc_name(u64 flags)
3600 {
3601         switch (flags) {
3602         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3603                 return "mixed";
3604         case BTRFS_BLOCK_GROUP_METADATA:
3605                 return "metadata";
3606         case BTRFS_BLOCK_GROUP_DATA:
3607                 return "data";
3608         case BTRFS_BLOCK_GROUP_SYSTEM:
3609                 return "system";
3610         default:
3611                 WARN_ON(1);
3612                 return "invalid-combination";
3613         };
3614 }
3615
3616 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3617                              u64 total_bytes, u64 bytes_used,
3618                              struct btrfs_space_info **space_info)
3619 {
3620         struct btrfs_space_info *found;
3621         int i;
3622         int factor;
3623         int ret;
3624
3625         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3626                      BTRFS_BLOCK_GROUP_RAID10))
3627                 factor = 2;
3628         else
3629                 factor = 1;
3630
3631         found = __find_space_info(info, flags);
3632         if (found) {
3633                 spin_lock(&found->lock);
3634                 found->total_bytes += total_bytes;
3635                 found->disk_total += total_bytes * factor;
3636                 found->bytes_used += bytes_used;
3637                 found->disk_used += bytes_used * factor;
3638                 if (total_bytes > 0)
3639                         found->full = 0;
3640                 spin_unlock(&found->lock);
3641                 *space_info = found;
3642                 return 0;
3643         }
3644         found = kzalloc(sizeof(*found), GFP_NOFS);
3645         if (!found)
3646                 return -ENOMEM;
3647
3648         ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3649         if (ret) {
3650                 kfree(found);
3651                 return ret;
3652         }
3653
3654         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3655                 INIT_LIST_HEAD(&found->block_groups[i]);
3656         init_rwsem(&found->groups_sem);
3657         spin_lock_init(&found->lock);
3658         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3659         found->total_bytes = total_bytes;
3660         found->disk_total = total_bytes * factor;
3661         found->bytes_used = bytes_used;
3662         found->disk_used = bytes_used * factor;
3663         found->bytes_pinned = 0;
3664         found->bytes_reserved = 0;
3665         found->bytes_readonly = 0;
3666         found->bytes_may_use = 0;
3667         if (total_bytes > 0)
3668                 found->full = 0;
3669         else
3670                 found->full = 1;
3671         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3672         found->chunk_alloc = 0;
3673         found->flush = 0;
3674         init_waitqueue_head(&found->wait);
3675         INIT_LIST_HEAD(&found->ro_bgs);
3676
3677         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3678                                     info->space_info_kobj, "%s",
3679                                     alloc_name(found->flags));
3680         if (ret) {
3681                 kfree(found);
3682                 return ret;
3683         }
3684
3685         *space_info = found;
3686         list_add_rcu(&found->list, &info->space_info);
3687         if (flags & BTRFS_BLOCK_GROUP_DATA)
3688                 info->data_sinfo = found;
3689
3690         return ret;
3691 }
3692
3693 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3694 {
3695         u64 extra_flags = chunk_to_extended(flags) &
3696                                 BTRFS_EXTENDED_PROFILE_MASK;
3697
3698         write_seqlock(&fs_info->profiles_lock);
3699         if (flags & BTRFS_BLOCK_GROUP_DATA)
3700                 fs_info->avail_data_alloc_bits |= extra_flags;
3701         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3702                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3703         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3704                 fs_info->avail_system_alloc_bits |= extra_flags;
3705         write_sequnlock(&fs_info->profiles_lock);
3706 }
3707
3708 /*
3709  * returns target flags in extended format or 0 if restripe for this
3710  * chunk_type is not in progress
3711  *
3712  * should be called with either volume_mutex or balance_lock held
3713  */
3714 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3715 {
3716         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3717         u64 target = 0;
3718
3719         if (!bctl)
3720                 return 0;
3721
3722         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3723             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3724                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3725         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3726                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3727                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3728         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3729                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3730                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3731         }
3732
3733         return target;
3734 }
3735
3736 /*
3737  * @flags: available profiles in extended format (see ctree.h)
3738  *
3739  * Returns reduced profile in chunk format.  If profile changing is in
3740  * progress (either running or paused) picks the target profile (if it's
3741  * already available), otherwise falls back to plain reducing.
3742  */
3743 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3744 {
3745         u64 num_devices = root->fs_info->fs_devices->rw_devices;
3746         u64 target;
3747         u64 tmp;
3748
3749         /*
3750          * see if restripe for this chunk_type is in progress, if so
3751          * try to reduce to the target profile
3752          */
3753         spin_lock(&root->fs_info->balance_lock);
3754         target = get_restripe_target(root->fs_info, flags);
3755         if (target) {
3756                 /* pick target profile only if it's already available */
3757                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3758                         spin_unlock(&root->fs_info->balance_lock);
3759                         return extended_to_chunk(target);
3760                 }
3761         }
3762         spin_unlock(&root->fs_info->balance_lock);
3763
3764         /* First, mask out the RAID levels which aren't possible */
3765         if (num_devices == 1)
3766                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3767                            BTRFS_BLOCK_GROUP_RAID5);
3768         if (num_devices < 3)
3769                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3770         if (num_devices < 4)
3771                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3772
3773         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3774                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3775                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3776         flags &= ~tmp;
3777
3778         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3779                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3780         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3781                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3782         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3783                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3784         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3785                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3786         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3787                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3788
3789         return extended_to_chunk(flags | tmp);
3790 }
3791
3792 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
3793 {
3794         unsigned seq;
3795         u64 flags;
3796
3797         do {
3798                 flags = orig_flags;
3799                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3800
3801                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3802                         flags |= root->fs_info->avail_data_alloc_bits;
3803                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3804                         flags |= root->fs_info->avail_system_alloc_bits;
3805                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3806                         flags |= root->fs_info->avail_metadata_alloc_bits;
3807         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3808
3809         return btrfs_reduce_alloc_profile(root, flags);
3810 }
3811
3812 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3813 {
3814         u64 flags;
3815         u64 ret;
3816
3817         if (data)
3818                 flags = BTRFS_BLOCK_GROUP_DATA;
3819         else if (root == root->fs_info->chunk_root)
3820                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3821         else
3822                 flags = BTRFS_BLOCK_GROUP_METADATA;
3823
3824         ret = get_alloc_profile(root, flags);
3825         return ret;
3826 }
3827
3828 /*
3829  * This will check the space that the inode allocates from to make sure we have
3830  * enough space for bytes.
3831  */
3832 int btrfs_check_data_free_space(struct inode *inode, u64 bytes, u64 write_bytes)
3833 {
3834         struct btrfs_space_info *data_sinfo;
3835         struct btrfs_root *root = BTRFS_I(inode)->root;
3836         struct btrfs_fs_info *fs_info = root->fs_info;
3837         u64 used;
3838         int ret = 0;
3839         int need_commit = 2;
3840         int have_pinned_space;
3841
3842         /* make sure bytes are sectorsize aligned */
3843         bytes = ALIGN(bytes, root->sectorsize);
3844
3845         if (btrfs_is_free_space_inode(inode)) {
3846                 need_commit = 0;
3847                 ASSERT(current->journal_info);
3848         }
3849
3850         data_sinfo = fs_info->data_sinfo;
3851         if (!data_sinfo)
3852                 goto alloc;
3853
3854 again:
3855         /* make sure we have enough space to handle the data first */
3856         spin_lock(&data_sinfo->lock);
3857         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3858                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3859                 data_sinfo->bytes_may_use;
3860
3861         if (used + bytes > data_sinfo->total_bytes) {
3862                 struct btrfs_trans_handle *trans;
3863
3864                 /*
3865                  * if we don't have enough free bytes in this space then we need
3866                  * to alloc a new chunk.
3867                  */
3868                 if (!data_sinfo->full) {
3869                         u64 alloc_target;
3870
3871                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3872                         spin_unlock(&data_sinfo->lock);
3873 alloc:
3874                         alloc_target = btrfs_get_alloc_profile(root, 1);
3875                         /*
3876                          * It is ugly that we don't call nolock join
3877                          * transaction for the free space inode case here.
3878                          * But it is safe because we only do the data space
3879                          * reservation for the free space cache in the
3880                          * transaction context, the common join transaction
3881                          * just increase the counter of the current transaction
3882                          * handler, doesn't try to acquire the trans_lock of
3883                          * the fs.
3884                          */
3885                         trans = btrfs_join_transaction(root);
3886                         if (IS_ERR(trans))
3887                                 return PTR_ERR(trans);
3888
3889                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3890                                              alloc_target,
3891                                              CHUNK_ALLOC_NO_FORCE);
3892                         btrfs_end_transaction(trans, root);
3893                         if (ret < 0) {
3894                                 if (ret != -ENOSPC)
3895                                         return ret;
3896                                 else {
3897                                         have_pinned_space = 1;
3898                                         goto commit_trans;
3899                                 }
3900                         }
3901
3902                         if (!data_sinfo)
3903                                 data_sinfo = fs_info->data_sinfo;
3904
3905                         goto again;
3906                 }
3907
3908                 /*
3909                  * If we don't have enough pinned space to deal with this
3910                  * allocation, and no removed chunk in current transaction,
3911                  * don't bother committing the transaction.
3912                  */
3913                 have_pinned_space = percpu_counter_compare(
3914                         &data_sinfo->total_bytes_pinned,
3915                         used + bytes - data_sinfo->total_bytes);
3916                 spin_unlock(&data_sinfo->lock);
3917
3918                 /* commit the current transaction and try again */
3919 commit_trans:
3920                 if (need_commit &&
3921                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3922                         need_commit--;
3923
3924                         trans = btrfs_join_transaction(root);
3925                         if (IS_ERR(trans))
3926                                 return PTR_ERR(trans);
3927                         if (have_pinned_space >= 0 ||
3928                             trans->transaction->have_free_bgs ||
3929                             need_commit > 0) {
3930                                 ret = btrfs_commit_transaction(trans, root);
3931                                 if (ret)
3932                                         return ret;
3933                                 /*
3934                                  * make sure that all running delayed iput are
3935                                  * done
3936                                  */
3937                                 down_write(&root->fs_info->delayed_iput_sem);
3938                                 up_write(&root->fs_info->delayed_iput_sem);
3939                                 goto again;
3940                         } else {
3941                                 btrfs_end_transaction(trans, root);
3942                         }
3943                 }
3944
3945                 trace_btrfs_space_reservation(root->fs_info,
3946                                               "space_info:enospc",
3947                                               data_sinfo->flags, bytes, 1);
3948                 return -ENOSPC;
3949         }
3950         ret = btrfs_qgroup_reserve(root, write_bytes);
3951         if (ret)
3952                 goto out;
3953         data_sinfo->bytes_may_use += bytes;
3954         trace_btrfs_space_reservation(root->fs_info, "space_info",
3955                                       data_sinfo->flags, bytes, 1);
3956 out:
3957         spin_unlock(&data_sinfo->lock);
3958
3959         return ret;
3960 }
3961
3962 /*
3963  * Called if we need to clear a data reservation for this inode.
3964  */
3965 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3966 {
3967         struct btrfs_root *root = BTRFS_I(inode)->root;
3968         struct btrfs_space_info *data_sinfo;
3969
3970         /* make sure bytes are sectorsize aligned */
3971         bytes = ALIGN(bytes, root->sectorsize);
3972
3973         data_sinfo = root->fs_info->data_sinfo;
3974         spin_lock(&data_sinfo->lock);
3975         WARN_ON(data_sinfo->bytes_may_use < bytes);
3976         data_sinfo->bytes_may_use -= bytes;
3977         trace_btrfs_space_reservation(root->fs_info, "space_info",
3978                                       data_sinfo->flags, bytes, 0);
3979         spin_unlock(&data_sinfo->lock);
3980 }
3981
3982 static void force_metadata_allocation(struct btrfs_fs_info *info)
3983 {
3984         struct list_head *head = &info->space_info;
3985         struct btrfs_space_info *found;
3986
3987         rcu_read_lock();
3988         list_for_each_entry_rcu(found, head, list) {
3989                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3990                         found->force_alloc = CHUNK_ALLOC_FORCE;
3991         }
3992         rcu_read_unlock();
3993 }
3994
3995 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3996 {
3997         return (global->size << 1);
3998 }
3999
4000 static int should_alloc_chunk(struct btrfs_root *root,
4001                               struct btrfs_space_info *sinfo, int force)
4002 {
4003         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4004         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4005         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4006         u64 thresh;
4007
4008         if (force == CHUNK_ALLOC_FORCE)
4009                 return 1;
4010
4011         /*
4012          * We need to take into account the global rsv because for all intents
4013          * and purposes it's used space.  Don't worry about locking the
4014          * global_rsv, it doesn't change except when the transaction commits.
4015          */
4016         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4017                 num_allocated += calc_global_rsv_need_space(global_rsv);
4018
4019         /*
4020          * in limited mode, we want to have some free space up to
4021          * about 1% of the FS size.
4022          */
4023         if (force == CHUNK_ALLOC_LIMITED) {
4024                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4025                 thresh = max_t(u64, 64 * 1024 * 1024,
4026                                div_factor_fine(thresh, 1));
4027
4028                 if (num_bytes - num_allocated < thresh)
4029                         return 1;
4030         }
4031
4032         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
4033                 return 0;
4034         return 1;
4035 }
4036
4037 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4038 {
4039         u64 num_dev;
4040
4041         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4042                     BTRFS_BLOCK_GROUP_RAID0 |
4043                     BTRFS_BLOCK_GROUP_RAID5 |
4044                     BTRFS_BLOCK_GROUP_RAID6))
4045                 num_dev = root->fs_info->fs_devices->rw_devices;
4046         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4047                 num_dev = 2;
4048         else
4049                 num_dev = 1;    /* DUP or single */
4050
4051         return num_dev;
4052 }
4053
4054 /*
4055  * If @is_allocation is true, reserve space in the system space info necessary
4056  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4057  * removing a chunk.
4058  */
4059 void check_system_chunk(struct btrfs_trans_handle *trans,
4060                         struct btrfs_root *root,
4061                         u64 type)
4062 {
4063         struct btrfs_space_info *info;
4064         u64 left;
4065         u64 thresh;
4066         int ret = 0;
4067         u64 num_devs;
4068
4069         /*
4070          * Needed because we can end up allocating a system chunk and for an
4071          * atomic and race free space reservation in the chunk block reserve.
4072          */
4073         ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4074
4075         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4076         spin_lock(&info->lock);
4077         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4078                 info->bytes_reserved - info->bytes_readonly -
4079                 info->bytes_may_use;
4080         spin_unlock(&info->lock);
4081
4082         num_devs = get_profile_num_devs(root, type);
4083
4084         /* num_devs device items to update and 1 chunk item to add or remove */
4085         thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4086                 btrfs_calc_trans_metadata_size(root, 1);
4087
4088         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
4089                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4090                         left, thresh, type);
4091                 dump_space_info(info, 0, 0);
4092         }
4093
4094         if (left < thresh) {
4095                 u64 flags;
4096
4097                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4098                 /*
4099                  * Ignore failure to create system chunk. We might end up not
4100                  * needing it, as we might not need to COW all nodes/leafs from
4101                  * the paths we visit in the chunk tree (they were already COWed
4102                  * or created in the current transaction for example).
4103                  */
4104                 ret = btrfs_alloc_chunk(trans, root, flags);
4105         }
4106
4107         if (!ret) {
4108                 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4109                                           &root->fs_info->chunk_block_rsv,
4110                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4111                 if (!ret)
4112                         trans->chunk_bytes_reserved += thresh;
4113         }
4114 }
4115
4116 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4117                           struct btrfs_root *extent_root, u64 flags, int force)
4118 {
4119         struct btrfs_space_info *space_info;
4120         struct btrfs_fs_info *fs_info = extent_root->fs_info;
4121         int wait_for_alloc = 0;
4122         int ret = 0;
4123
4124         /* Don't re-enter if we're already allocating a chunk */
4125         if (trans->allocating_chunk)
4126                 return -ENOSPC;
4127
4128         space_info = __find_space_info(extent_root->fs_info, flags);
4129         if (!space_info) {
4130                 ret = update_space_info(extent_root->fs_info, flags,
4131                                         0, 0, &space_info);
4132                 BUG_ON(ret); /* -ENOMEM */
4133         }
4134         BUG_ON(!space_info); /* Logic error */
4135
4136 again:
4137         spin_lock(&space_info->lock);
4138         if (force < space_info->force_alloc)
4139                 force = space_info->force_alloc;
4140         if (space_info->full) {
4141                 if (should_alloc_chunk(extent_root, space_info, force))
4142                         ret = -ENOSPC;
4143                 else
4144                         ret = 0;
4145                 spin_unlock(&space_info->lock);
4146                 return ret;
4147         }
4148
4149         if (!should_alloc_chunk(extent_root, space_info, force)) {
4150                 spin_unlock(&space_info->lock);
4151                 return 0;
4152         } else if (space_info->chunk_alloc) {
4153                 wait_for_alloc = 1;
4154         } else {
4155                 space_info->chunk_alloc = 1;
4156         }
4157
4158         spin_unlock(&space_info->lock);
4159
4160         mutex_lock(&fs_info->chunk_mutex);
4161
4162         /*
4163          * The chunk_mutex is held throughout the entirety of a chunk
4164          * allocation, so once we've acquired the chunk_mutex we know that the
4165          * other guy is done and we need to recheck and see if we should
4166          * allocate.
4167          */
4168         if (wait_for_alloc) {
4169                 mutex_unlock(&fs_info->chunk_mutex);
4170                 wait_for_alloc = 0;
4171                 goto again;
4172         }
4173
4174         trans->allocating_chunk = true;
4175
4176         /*
4177          * If we have mixed data/metadata chunks we want to make sure we keep
4178          * allocating mixed chunks instead of individual chunks.
4179          */
4180         if (btrfs_mixed_space_info(space_info))
4181                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4182
4183         /*
4184          * if we're doing a data chunk, go ahead and make sure that
4185          * we keep a reasonable number of metadata chunks allocated in the
4186          * FS as well.
4187          */
4188         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4189                 fs_info->data_chunk_allocations++;
4190                 if (!(fs_info->data_chunk_allocations %
4191                       fs_info->metadata_ratio))
4192                         force_metadata_allocation(fs_info);
4193         }
4194
4195         /*
4196          * Check if we have enough space in SYSTEM chunk because we may need
4197          * to update devices.
4198          */
4199         check_system_chunk(trans, extent_root, flags);
4200
4201         ret = btrfs_alloc_chunk(trans, extent_root, flags);
4202         trans->allocating_chunk = false;
4203
4204         spin_lock(&space_info->lock);
4205         if (ret < 0 && ret != -ENOSPC)
4206                 goto out;
4207         if (ret)
4208                 space_info->full = 1;
4209         else
4210                 ret = 1;
4211
4212         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4213 out:
4214         space_info->chunk_alloc = 0;
4215         spin_unlock(&space_info->lock);
4216         mutex_unlock(&fs_info->chunk_mutex);
4217         return ret;
4218 }
4219
4220 static int can_overcommit(struct btrfs_root *root,
4221                           struct btrfs_space_info *space_info, u64 bytes,
4222                           enum btrfs_reserve_flush_enum flush)
4223 {
4224         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4225         u64 profile = btrfs_get_alloc_profile(root, 0);
4226         u64 space_size;
4227         u64 avail;
4228         u64 used;
4229
4230         used = space_info->bytes_used + space_info->bytes_reserved +
4231                 space_info->bytes_pinned + space_info->bytes_readonly;
4232
4233         /*
4234          * We only want to allow over committing if we have lots of actual space
4235          * free, but if we don't have enough space to handle the global reserve
4236          * space then we could end up having a real enospc problem when trying
4237          * to allocate a chunk or some other such important allocation.
4238          */
4239         spin_lock(&global_rsv->lock);
4240         space_size = calc_global_rsv_need_space(global_rsv);
4241         spin_unlock(&global_rsv->lock);
4242         if (used + space_size >= space_info->total_bytes)
4243                 return 0;
4244
4245         used += space_info->bytes_may_use;
4246
4247         spin_lock(&root->fs_info->free_chunk_lock);
4248         avail = root->fs_info->free_chunk_space;
4249         spin_unlock(&root->fs_info->free_chunk_lock);
4250
4251         /*
4252          * If we have dup, raid1 or raid10 then only half of the free
4253          * space is actually useable.  For raid56, the space info used
4254          * doesn't include the parity drive, so we don't have to
4255          * change the math
4256          */
4257         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4258                        BTRFS_BLOCK_GROUP_RAID1 |
4259                        BTRFS_BLOCK_GROUP_RAID10))
4260                 avail >>= 1;
4261
4262         /*
4263          * If we aren't flushing all things, let us overcommit up to
4264          * 1/2th of the space. If we can flush, don't let us overcommit
4265          * too much, let it overcommit up to 1/8 of the space.
4266          */
4267         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4268                 avail >>= 3;
4269         else
4270                 avail >>= 1;
4271
4272         if (used + bytes < space_info->total_bytes + avail)
4273                 return 1;
4274         return 0;
4275 }
4276
4277 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4278                                          unsigned long nr_pages, int nr_items)
4279 {
4280         struct super_block *sb = root->fs_info->sb;
4281
4282         if (down_read_trylock(&sb->s_umount)) {
4283                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4284                 up_read(&sb->s_umount);
4285         } else {
4286                 /*
4287                  * We needn't worry the filesystem going from r/w to r/o though
4288                  * we don't acquire ->s_umount mutex, because the filesystem
4289                  * should guarantee the delalloc inodes list be empty after
4290                  * the filesystem is readonly(all dirty pages are written to
4291                  * the disk).
4292                  */
4293                 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4294                 if (!current->journal_info)
4295                         btrfs_wait_ordered_roots(root->fs_info, nr_items);
4296         }
4297 }
4298
4299 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4300 {
4301         u64 bytes;
4302         int nr;
4303
4304         bytes = btrfs_calc_trans_metadata_size(root, 1);
4305         nr = (int)div64_u64(to_reclaim, bytes);
4306         if (!nr)
4307                 nr = 1;
4308         return nr;
4309 }
4310
4311 #define EXTENT_SIZE_PER_ITEM    (256 * 1024)
4312
4313 /*
4314  * shrink metadata reservation for delalloc
4315  */
4316 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4317                             bool wait_ordered)
4318 {
4319         struct btrfs_block_rsv *block_rsv;
4320         struct btrfs_space_info *space_info;
4321         struct btrfs_trans_handle *trans;
4322         u64 delalloc_bytes;
4323         u64 max_reclaim;
4324         long time_left;
4325         unsigned long nr_pages;
4326         int loops;
4327         int items;
4328         enum btrfs_reserve_flush_enum flush;
4329
4330         /* Calc the number of the pages we need flush for space reservation */
4331         items = calc_reclaim_items_nr(root, to_reclaim);
4332         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4333
4334         trans = (struct btrfs_trans_handle *)current->journal_info;
4335         block_rsv = &root->fs_info->delalloc_block_rsv;
4336         space_info = block_rsv->space_info;
4337
4338         delalloc_bytes = percpu_counter_sum_positive(
4339                                                 &root->fs_info->delalloc_bytes);
4340         if (delalloc_bytes == 0) {
4341                 if (trans)
4342                         return;
4343                 if (wait_ordered)
4344                         btrfs_wait_ordered_roots(root->fs_info, items);
4345                 return;
4346         }
4347
4348         loops = 0;
4349         while (delalloc_bytes && loops < 3) {
4350                 max_reclaim = min(delalloc_bytes, to_reclaim);
4351                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4352                 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4353                 /*
4354                  * We need to wait for the async pages to actually start before
4355                  * we do anything.
4356                  */
4357                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4358                 if (!max_reclaim)
4359                         goto skip_async;
4360
4361                 if (max_reclaim <= nr_pages)
4362                         max_reclaim = 0;
4363                 else
4364                         max_reclaim -= nr_pages;
4365
4366                 wait_event(root->fs_info->async_submit_wait,
4367                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4368                            (int)max_reclaim);
4369 skip_async:
4370                 if (!trans)
4371                         flush = BTRFS_RESERVE_FLUSH_ALL;
4372                 else
4373                         flush = BTRFS_RESERVE_NO_FLUSH;
4374                 spin_lock(&space_info->lock);
4375                 if (can_overcommit(root, space_info, orig, flush)) {
4376                         spin_unlock(&space_info->lock);
4377                         break;
4378                 }
4379                 spin_unlock(&space_info->lock);
4380
4381                 loops++;
4382                 if (wait_ordered && !trans) {
4383                         btrfs_wait_ordered_roots(root->fs_info, items);
4384                 } else {
4385                         time_left = schedule_timeout_killable(1);
4386                         if (time_left)
4387                                 break;
4388                 }
4389                 delalloc_bytes = percpu_counter_sum_positive(
4390                                                 &root->fs_info->delalloc_bytes);
4391         }
4392 }
4393
4394 /**
4395  * maybe_commit_transaction - possibly commit the transaction if its ok to
4396  * @root - the root we're allocating for
4397  * @bytes - the number of bytes we want to reserve
4398  * @force - force the commit
4399  *
4400  * This will check to make sure that committing the transaction will actually
4401  * get us somewhere and then commit the transaction if it does.  Otherwise it
4402  * will return -ENOSPC.
4403  */
4404 static int may_commit_transaction(struct btrfs_root *root,
4405                                   struct btrfs_space_info *space_info,
4406                                   u64 bytes, int force)
4407 {
4408         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4409         struct btrfs_trans_handle *trans;
4410
4411         trans = (struct btrfs_trans_handle *)current->journal_info;
4412         if (trans)
4413                 return -EAGAIN;
4414
4415         if (force)
4416                 goto commit;
4417
4418         /* See if there is enough pinned space to make this reservation */
4419         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4420                                    bytes) >= 0)
4421                 goto commit;
4422
4423         /*
4424          * See if there is some space in the delayed insertion reservation for
4425          * this reservation.
4426          */
4427         if (space_info != delayed_rsv->space_info)
4428                 return -ENOSPC;
4429
4430         spin_lock(&delayed_rsv->lock);
4431         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4432                                    bytes - delayed_rsv->size) >= 0) {
4433                 spin_unlock(&delayed_rsv->lock);
4434                 return -ENOSPC;
4435         }
4436         spin_unlock(&delayed_rsv->lock);
4437
4438 commit:
4439         trans = btrfs_join_transaction(root);
4440         if (IS_ERR(trans))
4441                 return -ENOSPC;
4442
4443         return btrfs_commit_transaction(trans, root);
4444 }
4445
4446 enum flush_state {
4447         FLUSH_DELAYED_ITEMS_NR  =       1,
4448         FLUSH_DELAYED_ITEMS     =       2,
4449         FLUSH_DELALLOC          =       3,
4450         FLUSH_DELALLOC_WAIT     =       4,
4451         ALLOC_CHUNK             =       5,
4452         COMMIT_TRANS            =       6,
4453 };
4454
4455 static int flush_space(struct btrfs_root *root,
4456                        struct btrfs_space_info *space_info, u64 num_bytes,
4457                        u64 orig_bytes, int state)
4458 {
4459         struct btrfs_trans_handle *trans;
4460         int nr;
4461         int ret = 0;
4462
4463         switch (state) {
4464         case FLUSH_DELAYED_ITEMS_NR:
4465         case FLUSH_DELAYED_ITEMS:
4466                 if (state == FLUSH_DELAYED_ITEMS_NR)
4467                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4468                 else
4469                         nr = -1;
4470
4471                 trans = btrfs_join_transaction(root);
4472                 if (IS_ERR(trans)) {
4473                         ret = PTR_ERR(trans);
4474                         break;
4475                 }
4476                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4477                 btrfs_end_transaction(trans, root);
4478                 break;
4479         case FLUSH_DELALLOC:
4480         case FLUSH_DELALLOC_WAIT:
4481                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4482                                 state == FLUSH_DELALLOC_WAIT);
4483                 break;
4484         case ALLOC_CHUNK:
4485                 trans = btrfs_join_transaction(root);
4486                 if (IS_ERR(trans)) {
4487                         ret = PTR_ERR(trans);
4488                         break;
4489                 }
4490                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4491                                      btrfs_get_alloc_profile(root, 0),
4492                                      CHUNK_ALLOC_NO_FORCE);
4493                 btrfs_end_transaction(trans, root);
4494                 if (ret == -ENOSPC)
4495                         ret = 0;
4496                 break;
4497         case COMMIT_TRANS:
4498                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4499                 break;
4500         default:
4501                 ret = -ENOSPC;
4502                 break;
4503         }
4504
4505         return ret;
4506 }
4507
4508 static inline u64
4509 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4510                                  struct btrfs_space_info *space_info)
4511 {
4512         u64 used;
4513         u64 expected;
4514         u64 to_reclaim;
4515
4516         to_reclaim = min_t(u64, num_online_cpus() * 1024 * 1024,
4517                                 16 * 1024 * 1024);
4518         spin_lock(&space_info->lock);
4519         if (can_overcommit(root, space_info, to_reclaim,
4520                            BTRFS_RESERVE_FLUSH_ALL)) {
4521                 to_reclaim = 0;
4522                 goto out;
4523         }
4524
4525         used = space_info->bytes_used + space_info->bytes_reserved +
4526                space_info->bytes_pinned + space_info->bytes_readonly +
4527                space_info->bytes_may_use;
4528         if (can_overcommit(root, space_info, 1024 * 1024,
4529                            BTRFS_RESERVE_FLUSH_ALL))
4530                 expected = div_factor_fine(space_info->total_bytes, 95);
4531         else
4532                 expected = div_factor_fine(space_info->total_bytes, 90);
4533
4534         if (used > expected)
4535                 to_reclaim = used - expected;
4536         else
4537                 to_reclaim = 0;
4538         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4539                                      space_info->bytes_reserved);
4540 out:
4541         spin_unlock(&space_info->lock);
4542
4543         return to_reclaim;
4544 }
4545
4546 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4547                                         struct btrfs_fs_info *fs_info, u64 used)
4548 {
4549         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4550
4551         /* If we're just plain full then async reclaim just slows us down. */
4552         if (space_info->bytes_used >= thresh)
4553                 return 0;
4554
4555         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4556                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4557 }
4558
4559 static int btrfs_need_do_async_reclaim(struct btrfs_space_info *space_info,
4560                                        struct btrfs_fs_info *fs_info,
4561                                        int flush_state)
4562 {
4563         u64 used;
4564
4565         spin_lock(&space_info->lock);
4566         /*
4567          * We run out of space and have not got any free space via flush_space,
4568          * so don't bother doing async reclaim.
4569          */
4570         if (flush_state > COMMIT_TRANS && space_info->full) {
4571                 spin_unlock(&space_info->lock);
4572                 return 0;
4573         }
4574
4575         used = space_info->bytes_used + space_info->bytes_reserved +
4576                space_info->bytes_pinned + space_info->bytes_readonly +
4577                space_info->bytes_may_use;
4578         if (need_do_async_reclaim(space_info, fs_info, used)) {
4579                 spin_unlock(&space_info->lock);
4580                 return 1;
4581         }
4582         spin_unlock(&space_info->lock);
4583
4584         return 0;
4585 }
4586
4587 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4588 {
4589         struct btrfs_fs_info *fs_info;
4590         struct btrfs_space_info *space_info;
4591         u64 to_reclaim;
4592         int flush_state;
4593
4594         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4595         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4596
4597         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4598                                                       space_info);
4599         if (!to_reclaim)
4600                 return;
4601
4602         flush_state = FLUSH_DELAYED_ITEMS_NR;
4603         do {
4604                 flush_space(fs_info->fs_root, space_info, to_reclaim,
4605                             to_reclaim, flush_state);
4606                 flush_state++;
4607                 if (!btrfs_need_do_async_reclaim(space_info, fs_info,
4608                                                  flush_state))
4609                         return;
4610         } while (flush_state < COMMIT_TRANS);
4611 }
4612
4613 void btrfs_init_async_reclaim_work(struct work_struct *work)
4614 {
4615         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
4616 }
4617
4618 /**
4619  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4620  * @root - the root we're allocating for
4621  * @block_rsv - the block_rsv we're allocating for
4622  * @orig_bytes - the number of bytes we want
4623  * @flush - whether or not we can flush to make our reservation
4624  *
4625  * This will reserve orgi_bytes number of bytes from the space info associated
4626  * with the block_rsv.  If there is not enough space it will make an attempt to
4627  * flush out space to make room.  It will do this by flushing delalloc if
4628  * possible or committing the transaction.  If flush is 0 then no attempts to
4629  * regain reservations will be made and this will fail if there is not enough
4630  * space already.
4631  */
4632 static int reserve_metadata_bytes(struct btrfs_root *root,
4633                                   struct btrfs_block_rsv *block_rsv,
4634                                   u64 orig_bytes,
4635                                   enum btrfs_reserve_flush_enum flush)
4636 {
4637         struct btrfs_space_info *space_info = block_rsv->space_info;
4638         u64 used;
4639         u64 num_bytes = orig_bytes;
4640         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4641         int ret = 0;
4642         bool flushing = false;
4643
4644 again:
4645         ret = 0;
4646         spin_lock(&space_info->lock);
4647         /*
4648          * We only want to wait if somebody other than us is flushing and we
4649          * are actually allowed to flush all things.
4650          */
4651         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4652                space_info->flush) {
4653                 spin_unlock(&space_info->lock);
4654                 /*
4655                  * If we have a trans handle we can't wait because the flusher
4656                  * may have to commit the transaction, which would mean we would
4657                  * deadlock since we are waiting for the flusher to finish, but
4658                  * hold the current transaction open.
4659                  */
4660                 if (current->journal_info)
4661                         return -EAGAIN;
4662                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4663                 /* Must have been killed, return */
4664                 if (ret)
4665                         return -EINTR;
4666
4667                 spin_lock(&space_info->lock);
4668         }
4669
4670         ret = -ENOSPC;
4671         used = space_info->bytes_used + space_info->bytes_reserved +
4672                 space_info->bytes_pinned + space_info->bytes_readonly +
4673                 space_info->bytes_may_use;
4674
4675         /*
4676          * The idea here is that we've not already over-reserved the block group
4677          * then we can go ahead and save our reservation first and then start
4678          * flushing if we need to.  Otherwise if we've already overcommitted
4679          * lets start flushing stuff first and then come back and try to make
4680          * our reservation.
4681          */
4682         if (used <= space_info->total_bytes) {
4683                 if (used + orig_bytes <= space_info->total_bytes) {
4684                         space_info->bytes_may_use += orig_bytes;
4685                         trace_btrfs_space_reservation(root->fs_info,
4686                                 "space_info", space_info->flags, orig_bytes, 1);
4687                         ret = 0;
4688                 } else {
4689                         /*
4690                          * Ok set num_bytes to orig_bytes since we aren't
4691                          * overocmmitted, this way we only try and reclaim what
4692                          * we need.
4693                          */
4694                         num_bytes = orig_bytes;
4695                 }
4696         } else {
4697                 /*
4698                  * Ok we're over committed, set num_bytes to the overcommitted
4699                  * amount plus the amount of bytes that we need for this
4700                  * reservation.
4701                  */
4702                 num_bytes = used - space_info->total_bytes +
4703                         (orig_bytes * 2);
4704         }
4705
4706         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4707                 space_info->bytes_may_use += orig_bytes;
4708                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4709                                               space_info->flags, orig_bytes,
4710                                               1);
4711                 ret = 0;
4712         }
4713
4714         /*
4715          * Couldn't make our reservation, save our place so while we're trying
4716          * to reclaim space we can actually use it instead of somebody else
4717          * stealing it from us.
4718          *
4719          * We make the other tasks wait for the flush only when we can flush
4720          * all things.
4721          */
4722         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4723                 flushing = true;
4724                 space_info->flush = 1;
4725         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
4726                 used += orig_bytes;
4727                 /*
4728                  * We will do the space reservation dance during log replay,
4729                  * which means we won't have fs_info->fs_root set, so don't do
4730                  * the async reclaim as we will panic.
4731                  */
4732                 if (!root->fs_info->log_root_recovering &&
4733                     need_do_async_reclaim(space_info, root->fs_info, used) &&
4734                     !work_busy(&root->fs_info->async_reclaim_work))
4735                         queue_work(system_unbound_wq,
4736                                    &root->fs_info->async_reclaim_work);
4737         }
4738         spin_unlock(&space_info->lock);
4739
4740         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4741                 goto out;
4742
4743         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4744                           flush_state);
4745         flush_state++;
4746
4747         /*
4748          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4749          * would happen. So skip delalloc flush.
4750          */
4751         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4752             (flush_state == FLUSH_DELALLOC ||
4753              flush_state == FLUSH_DELALLOC_WAIT))
4754                 flush_state = ALLOC_CHUNK;
4755
4756         if (!ret)
4757                 goto again;
4758         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4759                  flush_state < COMMIT_TRANS)
4760                 goto again;
4761         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4762                  flush_state <= COMMIT_TRANS)
4763                 goto again;
4764
4765 out:
4766         if (ret == -ENOSPC &&
4767             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4768                 struct btrfs_block_rsv *global_rsv =
4769                         &root->fs_info->global_block_rsv;
4770
4771                 if (block_rsv != global_rsv &&
4772                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4773                         ret = 0;
4774         }
4775         if (ret == -ENOSPC)
4776                 trace_btrfs_space_reservation(root->fs_info,
4777                                               "space_info:enospc",
4778                                               space_info->flags, orig_bytes, 1);
4779         if (flushing) {
4780                 spin_lock(&space_info->lock);
4781                 space_info->flush = 0;
4782                 wake_up_all(&space_info->wait);
4783                 spin_unlock(&space_info->lock);
4784         }
4785         return ret;
4786 }
4787
4788 static struct btrfs_block_rsv *get_block_rsv(
4789                                         const struct btrfs_trans_handle *trans,
4790                                         const struct btrfs_root *root)
4791 {
4792         struct btrfs_block_rsv *block_rsv = NULL;
4793
4794         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4795                 block_rsv = trans->block_rsv;
4796
4797         if (root == root->fs_info->csum_root && trans->adding_csums)
4798                 block_rsv = trans->block_rsv;
4799
4800         if (root == root->fs_info->uuid_root)
4801                 block_rsv = trans->block_rsv;
4802
4803         if (!block_rsv)
4804                 block_rsv = root->block_rsv;
4805
4806         if (!block_rsv)
4807                 block_rsv = &root->fs_info->empty_block_rsv;
4808
4809         return block_rsv;
4810 }
4811
4812 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4813                                u64 num_bytes)
4814 {
4815         int ret = -ENOSPC;
4816         spin_lock(&block_rsv->lock);
4817         if (block_rsv->reserved >= num_bytes) {
4818                 block_rsv->reserved -= num_bytes;
4819                 if (block_rsv->reserved < block_rsv->size)
4820                         block_rsv->full = 0;
4821                 ret = 0;
4822         }
4823         spin_unlock(&block_rsv->lock);
4824         return ret;
4825 }
4826
4827 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4828                                 u64 num_bytes, int update_size)
4829 {
4830         spin_lock(&block_rsv->lock);
4831         block_rsv->reserved += num_bytes;
4832         if (update_size)
4833                 block_rsv->size += num_bytes;
4834         else if (block_rsv->reserved >= block_rsv->size)
4835                 block_rsv->full = 1;
4836         spin_unlock(&block_rsv->lock);
4837 }
4838
4839 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4840                              struct btrfs_block_rsv *dest, u64 num_bytes,
4841                              int min_factor)
4842 {
4843         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4844         u64 min_bytes;
4845
4846         if (global_rsv->space_info != dest->space_info)
4847                 return -ENOSPC;
4848
4849         spin_lock(&global_rsv->lock);
4850         min_bytes = div_factor(global_rsv->size, min_factor);
4851         if (global_rsv->reserved < min_bytes + num_bytes) {
4852                 spin_unlock(&global_rsv->lock);
4853                 return -ENOSPC;
4854         }
4855         global_rsv->reserved -= num_bytes;
4856         if (global_rsv->reserved < global_rsv->size)
4857                 global_rsv->full = 0;
4858         spin_unlock(&global_rsv->lock);
4859
4860         block_rsv_add_bytes(dest, num_bytes, 1);
4861         return 0;
4862 }
4863
4864 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4865                                     struct btrfs_block_rsv *block_rsv,
4866                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4867 {
4868         struct btrfs_space_info *space_info = block_rsv->space_info;
4869
4870         spin_lock(&block_rsv->lock);
4871         if (num_bytes == (u64)-1)
4872                 num_bytes = block_rsv->size;
4873         block_rsv->size -= num_bytes;
4874         if (block_rsv->reserved >= block_rsv->size) {
4875                 num_bytes = block_rsv->reserved - block_rsv->size;
4876                 block_rsv->reserved = block_rsv->size;
4877                 block_rsv->full = 1;
4878         } else {
4879                 num_bytes = 0;
4880         }
4881         spin_unlock(&block_rsv->lock);
4882
4883         if (num_bytes > 0) {
4884                 if (dest) {
4885                         spin_lock(&dest->lock);
4886                         if (!dest->full) {
4887                                 u64 bytes_to_add;
4888
4889                                 bytes_to_add = dest->size - dest->reserved;
4890                                 bytes_to_add = min(num_bytes, bytes_to_add);
4891                                 dest->reserved += bytes_to_add;
4892                                 if (dest->reserved >= dest->size)
4893                                         dest->full = 1;
4894                                 num_bytes -= bytes_to_add;
4895                         }
4896                         spin_unlock(&dest->lock);
4897                 }
4898                 if (num_bytes) {
4899                         spin_lock(&space_info->lock);
4900                         space_info->bytes_may_use -= num_bytes;
4901                         trace_btrfs_space_reservation(fs_info, "space_info",
4902                                         space_info->flags, num_bytes, 0);
4903                         spin_unlock(&space_info->lock);
4904                 }
4905         }
4906 }
4907
4908 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4909                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4910 {
4911         int ret;
4912
4913         ret = block_rsv_use_bytes(src, num_bytes);
4914         if (ret)
4915                 return ret;
4916
4917         block_rsv_add_bytes(dst, num_bytes, 1);
4918         return 0;
4919 }
4920
4921 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4922 {
4923         memset(rsv, 0, sizeof(*rsv));
4924         spin_lock_init(&rsv->lock);
4925         rsv->type = type;
4926 }
4927
4928 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4929                                               unsigned short type)
4930 {
4931         struct btrfs_block_rsv *block_rsv;
4932         struct btrfs_fs_info *fs_info = root->fs_info;
4933
4934         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4935         if (!block_rsv)
4936                 return NULL;
4937
4938         btrfs_init_block_rsv(block_rsv, type);
4939         block_rsv->space_info = __find_space_info(fs_info,
4940                                                   BTRFS_BLOCK_GROUP_METADATA);
4941         return block_rsv;
4942 }
4943
4944 void btrfs_free_block_rsv(struct btrfs_root *root,
4945                           struct btrfs_block_rsv *rsv)
4946 {
4947         if (!rsv)
4948                 return;
4949         btrfs_block_rsv_release(root, rsv, (u64)-1);
4950         kfree(rsv);
4951 }
4952
4953 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
4954 {
4955         kfree(rsv);
4956 }
4957
4958 int btrfs_block_rsv_add(struct btrfs_root *root,
4959                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4960                         enum btrfs_reserve_flush_enum flush)
4961 {
4962         int ret;
4963
4964         if (num_bytes == 0)
4965                 return 0;
4966
4967         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4968         if (!ret) {
4969                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4970                 return 0;
4971         }
4972
4973         return ret;
4974 }
4975
4976 int btrfs_block_rsv_check(struct btrfs_root *root,
4977                           struct btrfs_block_rsv *block_rsv, int min_factor)
4978 {
4979         u64 num_bytes = 0;
4980         int ret = -ENOSPC;
4981
4982         if (!block_rsv)
4983                 return 0;
4984
4985         spin_lock(&block_rsv->lock);
4986         num_bytes = div_factor(block_rsv->size, min_factor);
4987         if (block_rsv->reserved >= num_bytes)
4988                 ret = 0;
4989         spin_unlock(&block_rsv->lock);
4990
4991         return ret;
4992 }
4993
4994 int btrfs_block_rsv_refill(struct btrfs_root *root,
4995                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4996                            enum btrfs_reserve_flush_enum flush)
4997 {
4998         u64 num_bytes = 0;
4999         int ret = -ENOSPC;
5000
5001         if (!block_rsv)
5002                 return 0;
5003
5004         spin_lock(&block_rsv->lock);
5005         num_bytes = min_reserved;
5006         if (block_rsv->reserved >= num_bytes)
5007                 ret = 0;
5008         else
5009                 num_bytes -= block_rsv->reserved;
5010         spin_unlock(&block_rsv->lock);
5011
5012         if (!ret)
5013                 return 0;
5014
5015         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5016         if (!ret) {
5017                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5018                 return 0;
5019         }
5020
5021         return ret;
5022 }
5023
5024 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
5025                             struct btrfs_block_rsv *dst_rsv,
5026                             u64 num_bytes)
5027 {
5028         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5029 }
5030
5031 void btrfs_block_rsv_release(struct btrfs_root *root,
5032                              struct btrfs_block_rsv *block_rsv,
5033                              u64 num_bytes)
5034 {
5035         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5036         if (global_rsv == block_rsv ||
5037             block_rsv->space_info != global_rsv->space_info)
5038                 global_rsv = NULL;
5039         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5040                                 num_bytes);
5041 }
5042
5043 /*
5044  * helper to calculate size of global block reservation.
5045  * the desired value is sum of space used by extent tree,
5046  * checksum tree and root tree
5047  */
5048 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
5049 {
5050         struct btrfs_space_info *sinfo;
5051         u64 num_bytes;
5052         u64 meta_used;
5053         u64 data_used;
5054         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
5055
5056         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
5057         spin_lock(&sinfo->lock);
5058         data_used = sinfo->bytes_used;
5059         spin_unlock(&sinfo->lock);
5060
5061         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5062         spin_lock(&sinfo->lock);
5063         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
5064                 data_used = 0;
5065         meta_used = sinfo->bytes_used;
5066         spin_unlock(&sinfo->lock);
5067
5068         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
5069                     csum_size * 2;
5070         num_bytes += div_u64(data_used + meta_used, 50);
5071
5072         if (num_bytes * 3 > meta_used)
5073                 num_bytes = div_u64(meta_used, 3);
5074
5075         return ALIGN(num_bytes, fs_info->extent_root->nodesize << 10);
5076 }
5077
5078 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5079 {
5080         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5081         struct btrfs_space_info *sinfo = block_rsv->space_info;
5082         u64 num_bytes;
5083
5084         num_bytes = calc_global_metadata_size(fs_info);
5085
5086         spin_lock(&sinfo->lock);
5087         spin_lock(&block_rsv->lock);
5088
5089         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
5090
5091         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5092                     sinfo->bytes_reserved + sinfo->bytes_readonly +
5093                     sinfo->bytes_may_use;
5094
5095         if (sinfo->total_bytes > num_bytes) {
5096                 num_bytes = sinfo->total_bytes - num_bytes;
5097                 block_rsv->reserved += num_bytes;
5098                 sinfo->bytes_may_use += num_bytes;
5099                 trace_btrfs_space_reservation(fs_info, "space_info",
5100                                       sinfo->flags, num_bytes, 1);
5101         }
5102
5103         if (block_rsv->reserved >= block_rsv->size) {
5104                 num_bytes = block_rsv->reserved - block_rsv->size;
5105                 sinfo->bytes_may_use -= num_bytes;
5106                 trace_btrfs_space_reservation(fs_info, "space_info",
5107                                       sinfo->flags, num_bytes, 0);
5108                 block_rsv->reserved = block_rsv->size;
5109                 block_rsv->full = 1;
5110         }
5111
5112         spin_unlock(&block_rsv->lock);
5113         spin_unlock(&sinfo->lock);
5114 }
5115
5116 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5117 {
5118         struct btrfs_space_info *space_info;
5119
5120         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5121         fs_info->chunk_block_rsv.space_info = space_info;
5122
5123         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5124         fs_info->global_block_rsv.space_info = space_info;
5125         fs_info->delalloc_block_rsv.space_info = space_info;
5126         fs_info->trans_block_rsv.space_info = space_info;
5127         fs_info->empty_block_rsv.space_info = space_info;
5128         fs_info->delayed_block_rsv.space_info = space_info;
5129
5130         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5131         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5132         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5133         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5134         if (fs_info->quota_root)
5135                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5136         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5137
5138         update_global_block_rsv(fs_info);
5139 }
5140
5141 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5142 {
5143         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5144                                 (u64)-1);
5145         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5146         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5147         WARN_ON(fs_info->trans_block_rsv.size > 0);
5148         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5149         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5150         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5151         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5152         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5153 }
5154
5155 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5156                                   struct btrfs_root *root)
5157 {
5158         if (!trans->block_rsv)
5159                 return;
5160
5161         if (!trans->bytes_reserved)
5162                 return;
5163
5164         trace_btrfs_space_reservation(root->fs_info, "transaction",
5165                                       trans->transid, trans->bytes_reserved, 0);
5166         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5167         trans->bytes_reserved = 0;
5168 }
5169
5170 /*
5171  * To be called after all the new block groups attached to the transaction
5172  * handle have been created (btrfs_create_pending_block_groups()).
5173  */
5174 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5175 {
5176         struct btrfs_fs_info *fs_info = trans->root->fs_info;
5177
5178         if (!trans->chunk_bytes_reserved)
5179                 return;
5180
5181         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5182
5183         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5184                                 trans->chunk_bytes_reserved);
5185         trans->chunk_bytes_reserved = 0;
5186 }
5187
5188 /* Can only return 0 or -ENOSPC */
5189 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5190                                   struct inode *inode)
5191 {
5192         struct btrfs_root *root = BTRFS_I(inode)->root;
5193         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
5194         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5195
5196         /*
5197          * We need to hold space in order to delete our orphan item once we've
5198          * added it, so this takes the reservation so we can release it later
5199          * when we are truly done with the orphan item.
5200          */
5201         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5202         trace_btrfs_space_reservation(root->fs_info, "orphan",
5203                                       btrfs_ino(inode), num_bytes, 1);
5204         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5205 }
5206
5207 void btrfs_orphan_release_metadata(struct inode *inode)
5208 {
5209         struct btrfs_root *root = BTRFS_I(inode)->root;
5210         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5211         trace_btrfs_space_reservation(root->fs_info, "orphan",
5212                                       btrfs_ino(inode), num_bytes, 0);
5213         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5214 }
5215
5216 /*
5217  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5218  * root: the root of the parent directory
5219  * rsv: block reservation
5220  * items: the number of items that we need do reservation
5221  * qgroup_reserved: used to return the reserved size in qgroup
5222  *
5223  * This function is used to reserve the space for snapshot/subvolume
5224  * creation and deletion. Those operations are different with the
5225  * common file/directory operations, they change two fs/file trees
5226  * and root tree, the number of items that the qgroup reserves is
5227  * different with the free space reservation. So we can not use
5228  * the space reseravtion mechanism in start_transaction().
5229  */
5230 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5231                                      struct btrfs_block_rsv *rsv,
5232                                      int items,
5233                                      u64 *qgroup_reserved,
5234                                      bool use_global_rsv)
5235 {
5236         u64 num_bytes;
5237         int ret;
5238         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5239
5240         if (root->fs_info->quota_enabled) {
5241                 /* One for parent inode, two for dir entries */
5242                 num_bytes = 3 * root->nodesize;
5243                 ret = btrfs_qgroup_reserve(root, num_bytes);
5244                 if (ret)
5245                         return ret;
5246         } else {
5247                 num_bytes = 0;
5248         }
5249
5250         *qgroup_reserved = num_bytes;
5251
5252         num_bytes = btrfs_calc_trans_metadata_size(root, items);
5253         rsv->space_info = __find_space_info(root->fs_info,
5254                                             BTRFS_BLOCK_GROUP_METADATA);
5255         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5256                                   BTRFS_RESERVE_FLUSH_ALL);
5257
5258         if (ret == -ENOSPC && use_global_rsv)
5259                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
5260
5261         if (ret) {
5262                 if (*qgroup_reserved)
5263                         btrfs_qgroup_free(root, *qgroup_reserved);
5264         }
5265
5266         return ret;
5267 }
5268
5269 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5270                                       struct btrfs_block_rsv *rsv,
5271                                       u64 qgroup_reserved)
5272 {
5273         btrfs_block_rsv_release(root, rsv, (u64)-1);
5274 }
5275
5276 /**
5277  * drop_outstanding_extent - drop an outstanding extent
5278  * @inode: the inode we're dropping the extent for
5279  * @num_bytes: the number of bytes we're relaseing.
5280  *
5281  * This is called when we are freeing up an outstanding extent, either called
5282  * after an error or after an extent is written.  This will return the number of
5283  * reserved extents that need to be freed.  This must be called with
5284  * BTRFS_I(inode)->lock held.
5285  */
5286 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5287 {
5288         unsigned drop_inode_space = 0;
5289         unsigned dropped_extents = 0;
5290         unsigned num_extents = 0;
5291
5292         num_extents = (unsigned)div64_u64(num_bytes +
5293                                           BTRFS_MAX_EXTENT_SIZE - 1,
5294                                           BTRFS_MAX_EXTENT_SIZE);
5295         ASSERT(num_extents);
5296         ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5297         BTRFS_I(inode)->outstanding_extents -= num_extents;
5298
5299         if (BTRFS_I(inode)->outstanding_extents == 0 &&
5300             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5301                                &BTRFS_I(inode)->runtime_flags))
5302                 drop_inode_space = 1;
5303
5304         /*
5305          * If we have more or the same amount of outsanding extents than we have
5306          * reserved then we need to leave the reserved extents count alone.
5307          */
5308         if (BTRFS_I(inode)->outstanding_extents >=
5309             BTRFS_I(inode)->reserved_extents)
5310                 return drop_inode_space;
5311
5312         dropped_extents = BTRFS_I(inode)->reserved_extents -
5313                 BTRFS_I(inode)->outstanding_extents;
5314         BTRFS_I(inode)->reserved_extents -= dropped_extents;
5315         return dropped_extents + drop_inode_space;
5316 }
5317
5318 /**
5319  * calc_csum_metadata_size - return the amount of metada space that must be
5320  *      reserved/free'd for the given bytes.
5321  * @inode: the inode we're manipulating
5322  * @num_bytes: the number of bytes in question
5323  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5324  *
5325  * This adjusts the number of csum_bytes in the inode and then returns the
5326  * correct amount of metadata that must either be reserved or freed.  We
5327  * calculate how many checksums we can fit into one leaf and then divide the
5328  * number of bytes that will need to be checksumed by this value to figure out
5329  * how many checksums will be required.  If we are adding bytes then the number
5330  * may go up and we will return the number of additional bytes that must be
5331  * reserved.  If it is going down we will return the number of bytes that must
5332  * be freed.
5333  *
5334  * This must be called with BTRFS_I(inode)->lock held.
5335  */
5336 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5337                                    int reserve)
5338 {
5339         struct btrfs_root *root = BTRFS_I(inode)->root;
5340         u64 old_csums, num_csums;
5341
5342         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5343             BTRFS_I(inode)->csum_bytes == 0)
5344                 return 0;
5345
5346         old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5347         if (reserve)
5348                 BTRFS_I(inode)->csum_bytes += num_bytes;
5349         else
5350                 BTRFS_I(inode)->csum_bytes -= num_bytes;
5351         num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5352
5353         /* No change, no need to reserve more */
5354         if (old_csums == num_csums)
5355                 return 0;
5356
5357         if (reserve)
5358                 return btrfs_calc_trans_metadata_size(root,
5359                                                       num_csums - old_csums);
5360
5361         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5362 }
5363
5364 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5365 {
5366         struct btrfs_root *root = BTRFS_I(inode)->root;
5367         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5368         u64 to_reserve = 0;
5369         u64 csum_bytes;
5370         unsigned nr_extents = 0;
5371         int extra_reserve = 0;
5372         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5373         int ret = 0;
5374         bool delalloc_lock = true;
5375         u64 to_free = 0;
5376         unsigned dropped;
5377
5378         /* If we are a free space inode we need to not flush since we will be in
5379          * the middle of a transaction commit.  We also don't need the delalloc
5380          * mutex since we won't race with anybody.  We need this mostly to make
5381          * lockdep shut its filthy mouth.
5382          */
5383         if (btrfs_is_free_space_inode(inode)) {
5384                 flush = BTRFS_RESERVE_NO_FLUSH;
5385                 delalloc_lock = false;
5386         }
5387
5388         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5389             btrfs_transaction_in_commit(root->fs_info))
5390                 schedule_timeout(1);
5391
5392         if (delalloc_lock)
5393                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5394
5395         num_bytes = ALIGN(num_bytes, root->sectorsize);
5396
5397         spin_lock(&BTRFS_I(inode)->lock);
5398         nr_extents = (unsigned)div64_u64(num_bytes +
5399                                          BTRFS_MAX_EXTENT_SIZE - 1,
5400                                          BTRFS_MAX_EXTENT_SIZE);
5401         BTRFS_I(inode)->outstanding_extents += nr_extents;
5402         nr_extents = 0;
5403
5404         if (BTRFS_I(inode)->outstanding_extents >
5405             BTRFS_I(inode)->reserved_extents)
5406                 nr_extents = BTRFS_I(inode)->outstanding_extents -
5407                         BTRFS_I(inode)->reserved_extents;
5408
5409         /*
5410          * Add an item to reserve for updating the inode when we complete the
5411          * delalloc io.
5412          */
5413         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5414                       &BTRFS_I(inode)->runtime_flags)) {
5415                 nr_extents++;
5416                 extra_reserve = 1;
5417         }
5418
5419         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5420         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5421         csum_bytes = BTRFS_I(inode)->csum_bytes;
5422         spin_unlock(&BTRFS_I(inode)->lock);
5423
5424         if (root->fs_info->quota_enabled) {
5425                 ret = btrfs_qgroup_reserve(root, nr_extents * root->nodesize);
5426                 if (ret)
5427                         goto out_fail;
5428         }
5429
5430         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5431         if (unlikely(ret)) {
5432                 if (root->fs_info->quota_enabled)
5433                         btrfs_qgroup_free(root, nr_extents * root->nodesize);
5434                 goto out_fail;
5435         }
5436
5437         spin_lock(&BTRFS_I(inode)->lock);
5438         if (extra_reserve) {
5439                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5440                         &BTRFS_I(inode)->runtime_flags);
5441                 nr_extents--;
5442         }
5443         BTRFS_I(inode)->reserved_extents += nr_extents;
5444         spin_unlock(&BTRFS_I(inode)->lock);
5445
5446         if (delalloc_lock)
5447                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5448
5449         if (to_reserve)
5450                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5451                                               btrfs_ino(inode), to_reserve, 1);
5452         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5453
5454         return 0;
5455
5456 out_fail:
5457         spin_lock(&BTRFS_I(inode)->lock);
5458         dropped = drop_outstanding_extent(inode, num_bytes);
5459         /*
5460          * If the inodes csum_bytes is the same as the original
5461          * csum_bytes then we know we haven't raced with any free()ers
5462          * so we can just reduce our inodes csum bytes and carry on.
5463          */
5464         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5465                 calc_csum_metadata_size(inode, num_bytes, 0);
5466         } else {
5467                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5468                 u64 bytes;
5469
5470                 /*
5471                  * This is tricky, but first we need to figure out how much we
5472                  * free'd from any free-ers that occured during this
5473                  * reservation, so we reset ->csum_bytes to the csum_bytes
5474                  * before we dropped our lock, and then call the free for the
5475                  * number of bytes that were freed while we were trying our
5476                  * reservation.
5477                  */
5478                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5479                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5480                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5481
5482
5483                 /*
5484                  * Now we need to see how much we would have freed had we not
5485                  * been making this reservation and our ->csum_bytes were not
5486                  * artificially inflated.
5487                  */
5488                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5489                 bytes = csum_bytes - orig_csum_bytes;
5490                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5491
5492                 /*
5493                  * Now reset ->csum_bytes to what it should be.  If bytes is
5494                  * more than to_free then we would have free'd more space had we
5495                  * not had an artificially high ->csum_bytes, so we need to free
5496                  * the remainder.  If bytes is the same or less then we don't
5497                  * need to do anything, the other free-ers did the correct
5498                  * thing.
5499                  */
5500                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5501                 if (bytes > to_free)
5502                         to_free = bytes - to_free;
5503                 else
5504                         to_free = 0;
5505         }
5506         spin_unlock(&BTRFS_I(inode)->lock);
5507         if (dropped)
5508                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5509
5510         if (to_free) {
5511                 btrfs_block_rsv_release(root, block_rsv, to_free);
5512                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5513                                               btrfs_ino(inode), to_free, 0);
5514         }
5515         if (delalloc_lock)
5516                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5517         return ret;
5518 }
5519
5520 /**
5521  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5522  * @inode: the inode to release the reservation for
5523  * @num_bytes: the number of bytes we're releasing
5524  *
5525  * This will release the metadata reservation for an inode.  This can be called
5526  * once we complete IO for a given set of bytes to release their metadata
5527  * reservations.
5528  */
5529 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5530 {
5531         struct btrfs_root *root = BTRFS_I(inode)->root;
5532         u64 to_free = 0;
5533         unsigned dropped;
5534
5535         num_bytes = ALIGN(num_bytes, root->sectorsize);
5536         spin_lock(&BTRFS_I(inode)->lock);
5537         dropped = drop_outstanding_extent(inode, num_bytes);
5538
5539         if (num_bytes)
5540                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5541         spin_unlock(&BTRFS_I(inode)->lock);
5542         if (dropped > 0)
5543                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5544
5545         if (btrfs_test_is_dummy_root(root))
5546                 return;
5547
5548         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5549                                       btrfs_ino(inode), to_free, 0);
5550
5551         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5552                                 to_free);
5553 }
5554
5555 /**
5556  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5557  * @inode: inode we're writing to
5558  * @num_bytes: the number of bytes we want to allocate
5559  *
5560  * This will do the following things
5561  *
5562  * o reserve space in the data space info for num_bytes
5563  * o reserve space in the metadata space info based on number of outstanding
5564  *   extents and how much csums will be needed
5565  * o add to the inodes ->delalloc_bytes
5566  * o add it to the fs_info's delalloc inodes list.
5567  *
5568  * This will return 0 for success and -ENOSPC if there is no space left.
5569  */
5570 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5571 {
5572         int ret;
5573
5574         ret = btrfs_check_data_free_space(inode, num_bytes, num_bytes);
5575         if (ret)
5576                 return ret;
5577
5578         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5579         if (ret) {
5580                 btrfs_free_reserved_data_space(inode, num_bytes);
5581                 return ret;
5582         }
5583
5584         return 0;
5585 }
5586
5587 /**
5588  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5589  * @inode: inode we're releasing space for
5590  * @num_bytes: the number of bytes we want to free up
5591  *
5592  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5593  * called in the case that we don't need the metadata AND data reservations
5594  * anymore.  So if there is an error or we insert an inline extent.
5595  *
5596  * This function will release the metadata space that was not used and will
5597  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5598  * list if there are no delalloc bytes left.
5599  */
5600 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5601 {
5602         btrfs_delalloc_release_metadata(inode, num_bytes);
5603         btrfs_free_reserved_data_space(inode, num_bytes);
5604 }
5605
5606 static int update_block_group(struct btrfs_trans_handle *trans,
5607                               struct btrfs_root *root, u64 bytenr,
5608                               u64 num_bytes, int alloc)
5609 {
5610         struct btrfs_block_group_cache *cache = NULL;
5611         struct btrfs_fs_info *info = root->fs_info;
5612         u64 total = num_bytes;
5613         u64 old_val;
5614         u64 byte_in_group;
5615         int factor;
5616
5617         /* block accounting for super block */
5618         spin_lock(&info->delalloc_root_lock);
5619         old_val = btrfs_super_bytes_used(info->super_copy);
5620         if (alloc)
5621                 old_val += num_bytes;
5622         else
5623                 old_val -= num_bytes;
5624         btrfs_set_super_bytes_used(info->super_copy, old_val);
5625         spin_unlock(&info->delalloc_root_lock);
5626
5627         while (total) {
5628                 cache = btrfs_lookup_block_group(info, bytenr);
5629                 if (!cache)
5630                         return -ENOENT;
5631                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5632                                     BTRFS_BLOCK_GROUP_RAID1 |
5633                                     BTRFS_BLOCK_GROUP_RAID10))
5634                         factor = 2;
5635                 else
5636                         factor = 1;
5637                 /*
5638                  * If this block group has free space cache written out, we
5639                  * need to make sure to load it if we are removing space.  This
5640                  * is because we need the unpinning stage to actually add the
5641                  * space back to the block group, otherwise we will leak space.
5642                  */
5643                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5644                         cache_block_group(cache, 1);
5645
5646                 byte_in_group = bytenr - cache->key.objectid;
5647                 WARN_ON(byte_in_group > cache->key.offset);
5648
5649                 spin_lock(&cache->space_info->lock);
5650                 spin_lock(&cache->lock);
5651
5652                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5653                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5654                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5655
5656                 old_val = btrfs_block_group_used(&cache->item);
5657                 num_bytes = min(total, cache->key.offset - byte_in_group);
5658                 if (alloc) {
5659                         old_val += num_bytes;
5660                         btrfs_set_block_group_used(&cache->item, old_val);
5661                         cache->reserved -= num_bytes;
5662                         cache->space_info->bytes_reserved -= num_bytes;
5663                         cache->space_info->bytes_used += num_bytes;
5664                         cache->space_info->disk_used += num_bytes * factor;
5665                         spin_unlock(&cache->lock);
5666                         spin_unlock(&cache->space_info->lock);
5667                 } else {
5668                         old_val -= num_bytes;
5669                         btrfs_set_block_group_used(&cache->item, old_val);
5670                         cache->pinned += num_bytes;
5671                         cache->space_info->bytes_pinned += num_bytes;
5672                         cache->space_info->bytes_used -= num_bytes;
5673                         cache->space_info->disk_used -= num_bytes * factor;
5674                         spin_unlock(&cache->lock);
5675                         spin_unlock(&cache->space_info->lock);
5676
5677                         set_extent_dirty(info->pinned_extents,
5678                                          bytenr, bytenr + num_bytes - 1,
5679                                          GFP_NOFS | __GFP_NOFAIL);
5680                         /*
5681                          * No longer have used bytes in this block group, queue
5682                          * it for deletion.
5683                          */
5684                         if (old_val == 0) {
5685                                 spin_lock(&info->unused_bgs_lock);
5686                                 if (list_empty(&cache->bg_list)) {
5687                                         btrfs_get_block_group(cache);
5688                                         list_add_tail(&cache->bg_list,
5689                                                       &info->unused_bgs);
5690                                 }
5691                                 spin_unlock(&info->unused_bgs_lock);
5692                         }
5693                 }
5694
5695                 spin_lock(&trans->transaction->dirty_bgs_lock);
5696                 if (list_empty(&cache->dirty_list)) {
5697                         list_add_tail(&cache->dirty_list,
5698                                       &trans->transaction->dirty_bgs);
5699                                 trans->transaction->num_dirty_bgs++;
5700                         btrfs_get_block_group(cache);
5701                 }
5702                 spin_unlock(&trans->transaction->dirty_bgs_lock);
5703
5704                 btrfs_put_block_group(cache);
5705                 total -= num_bytes;
5706                 bytenr += num_bytes;
5707         }
5708         return 0;
5709 }
5710
5711 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5712 {
5713         struct btrfs_block_group_cache *cache;
5714         u64 bytenr;
5715
5716         spin_lock(&root->fs_info->block_group_cache_lock);
5717         bytenr = root->fs_info->first_logical_byte;
5718         spin_unlock(&root->fs_info->block_group_cache_lock);
5719
5720         if (bytenr < (u64)-1)
5721                 return bytenr;
5722
5723         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5724         if (!cache)
5725                 return 0;
5726
5727         bytenr = cache->key.objectid;
5728         btrfs_put_block_group(cache);
5729
5730         return bytenr;
5731 }
5732
5733 static int pin_down_extent(struct btrfs_root *root,
5734                            struct btrfs_block_group_cache *cache,
5735                            u64 bytenr, u64 num_bytes, int reserved)
5736 {
5737         spin_lock(&cache->space_info->lock);
5738         spin_lock(&cache->lock);
5739         cache->pinned += num_bytes;
5740         cache->space_info->bytes_pinned += num_bytes;
5741         if (reserved) {
5742                 cache->reserved -= num_bytes;
5743                 cache->space_info->bytes_reserved -= num_bytes;
5744         }
5745         spin_unlock(&cache->lock);
5746         spin_unlock(&cache->space_info->lock);
5747
5748         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5749                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5750         if (reserved)
5751                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
5752         return 0;
5753 }
5754
5755 /*
5756  * this function must be called within transaction
5757  */
5758 int btrfs_pin_extent(struct btrfs_root *root,
5759                      u64 bytenr, u64 num_bytes, int reserved)
5760 {
5761         struct btrfs_block_group_cache *cache;
5762
5763         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5764         BUG_ON(!cache); /* Logic error */
5765
5766         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5767
5768         btrfs_put_block_group(cache);
5769         return 0;
5770 }
5771
5772 /*
5773  * this function must be called within transaction
5774  */
5775 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5776                                     u64 bytenr, u64 num_bytes)
5777 {
5778         struct btrfs_block_group_cache *cache;
5779         int ret;
5780
5781         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5782         if (!cache)
5783                 return -EINVAL;
5784
5785         /*
5786          * pull in the free space cache (if any) so that our pin
5787          * removes the free space from the cache.  We have load_only set
5788          * to one because the slow code to read in the free extents does check
5789          * the pinned extents.
5790          */
5791         cache_block_group(cache, 1);
5792
5793         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5794
5795         /* remove us from the free space cache (if we're there at all) */
5796         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5797         btrfs_put_block_group(cache);
5798         return ret;
5799 }
5800
5801 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5802 {
5803         int ret;
5804         struct btrfs_block_group_cache *block_group;
5805         struct btrfs_caching_control *caching_ctl;
5806
5807         block_group = btrfs_lookup_block_group(root->fs_info, start);
5808         if (!block_group)
5809                 return -EINVAL;
5810
5811         cache_block_group(block_group, 0);
5812         caching_ctl = get_caching_control(block_group);
5813
5814         if (!caching_ctl) {
5815                 /* Logic error */
5816                 BUG_ON(!block_group_cache_done(block_group));
5817                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5818         } else {
5819                 mutex_lock(&caching_ctl->mutex);
5820
5821                 if (start >= caching_ctl->progress) {
5822                         ret = add_excluded_extent(root, start, num_bytes);
5823                 } else if (start + num_bytes <= caching_ctl->progress) {
5824                         ret = btrfs_remove_free_space(block_group,
5825                                                       start, num_bytes);
5826                 } else {
5827                         num_bytes = caching_ctl->progress - start;
5828                         ret = btrfs_remove_free_space(block_group,
5829                                                       start, num_bytes);
5830                         if (ret)
5831                                 goto out_lock;
5832
5833                         num_bytes = (start + num_bytes) -
5834                                 caching_ctl->progress;
5835                         start = caching_ctl->progress;
5836                         ret = add_excluded_extent(root, start, num_bytes);
5837                 }
5838 out_lock:
5839                 mutex_unlock(&caching_ctl->mutex);
5840                 put_caching_control(caching_ctl);
5841         }
5842         btrfs_put_block_group(block_group);
5843         return ret;
5844 }
5845
5846 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5847                                  struct extent_buffer *eb)
5848 {
5849         struct btrfs_file_extent_item *item;
5850         struct btrfs_key key;
5851         int found_type;
5852         int i;
5853
5854         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5855                 return 0;
5856
5857         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5858                 btrfs_item_key_to_cpu(eb, &key, i);
5859                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5860                         continue;
5861                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5862                 found_type = btrfs_file_extent_type(eb, item);
5863                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5864                         continue;
5865                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5866                         continue;
5867                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5868                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5869                 __exclude_logged_extent(log, key.objectid, key.offset);
5870         }
5871
5872         return 0;
5873 }
5874
5875 /**
5876  * btrfs_update_reserved_bytes - update the block_group and space info counters
5877  * @cache:      The cache we are manipulating
5878  * @num_bytes:  The number of bytes in question
5879  * @reserve:    One of the reservation enums
5880  * @delalloc:   The blocks are allocated for the delalloc write
5881  *
5882  * This is called by the allocator when it reserves space, or by somebody who is
5883  * freeing space that was never actually used on disk.  For example if you
5884  * reserve some space for a new leaf in transaction A and before transaction A
5885  * commits you free that leaf, you call this with reserve set to 0 in order to
5886  * clear the reservation.
5887  *
5888  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5889  * ENOSPC accounting.  For data we handle the reservation through clearing the
5890  * delalloc bits in the io_tree.  We have to do this since we could end up
5891  * allocating less disk space for the amount of data we have reserved in the
5892  * case of compression.
5893  *
5894  * If this is a reservation and the block group has become read only we cannot
5895  * make the reservation and return -EAGAIN, otherwise this function always
5896  * succeeds.
5897  */
5898 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5899                                        u64 num_bytes, int reserve, int delalloc)
5900 {
5901         struct btrfs_space_info *space_info = cache->space_info;
5902         int ret = 0;
5903
5904         spin_lock(&space_info->lock);
5905         spin_lock(&cache->lock);
5906         if (reserve != RESERVE_FREE) {
5907                 if (cache->ro) {
5908                         ret = -EAGAIN;
5909                 } else {
5910                         cache->reserved += num_bytes;
5911                         space_info->bytes_reserved += num_bytes;
5912                         if (reserve == RESERVE_ALLOC) {
5913                                 trace_btrfs_space_reservation(cache->fs_info,
5914                                                 "space_info", space_info->flags,
5915                                                 num_bytes, 0);
5916                                 space_info->bytes_may_use -= num_bytes;
5917                         }
5918
5919                         if (delalloc)
5920                                 cache->delalloc_bytes += num_bytes;
5921                 }
5922         } else {
5923                 if (cache->ro)
5924                         space_info->bytes_readonly += num_bytes;
5925                 cache->reserved -= num_bytes;
5926                 space_info->bytes_reserved -= num_bytes;
5927
5928                 if (delalloc)
5929                         cache->delalloc_bytes -= num_bytes;
5930         }
5931         spin_unlock(&cache->lock);
5932         spin_unlock(&space_info->lock);
5933         return ret;
5934 }
5935
5936 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5937                                 struct btrfs_root *root)
5938 {
5939         struct btrfs_fs_info *fs_info = root->fs_info;
5940         struct btrfs_caching_control *next;
5941         struct btrfs_caching_control *caching_ctl;
5942         struct btrfs_block_group_cache *cache;
5943
5944         down_write(&fs_info->commit_root_sem);
5945
5946         list_for_each_entry_safe(caching_ctl, next,
5947                                  &fs_info->caching_block_groups, list) {
5948                 cache = caching_ctl->block_group;
5949                 if (block_group_cache_done(cache)) {
5950                         cache->last_byte_to_unpin = (u64)-1;
5951                         list_del_init(&caching_ctl->list);
5952                         put_caching_control(caching_ctl);
5953                 } else {
5954                         cache->last_byte_to_unpin = caching_ctl->progress;
5955                 }
5956         }
5957
5958         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5959                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5960         else
5961                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5962
5963         up_write(&fs_info->commit_root_sem);
5964
5965         update_global_block_rsv(fs_info);
5966 }
5967
5968 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
5969                               const bool return_free_space)
5970 {
5971         struct btrfs_fs_info *fs_info = root->fs_info;
5972         struct btrfs_block_group_cache *cache = NULL;
5973         struct btrfs_space_info *space_info;
5974         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5975         u64 len;
5976         bool readonly;
5977
5978         while (start <= end) {
5979                 readonly = false;
5980                 if (!cache ||
5981                     start >= cache->key.objectid + cache->key.offset) {
5982                         if (cache)
5983                                 btrfs_put_block_group(cache);
5984                         cache = btrfs_lookup_block_group(fs_info, start);
5985                         BUG_ON(!cache); /* Logic error */
5986                 }
5987
5988                 len = cache->key.objectid + cache->key.offset - start;
5989                 len = min(len, end + 1 - start);
5990
5991                 if (start < cache->last_byte_to_unpin) {
5992                         len = min(len, cache->last_byte_to_unpin - start);
5993                         if (return_free_space)
5994                                 btrfs_add_free_space(cache, start, len);
5995                 }
5996
5997                 start += len;
5998                 space_info = cache->space_info;
5999
6000                 spin_lock(&space_info->lock);
6001                 spin_lock(&cache->lock);
6002                 cache->pinned -= len;
6003                 space_info->bytes_pinned -= len;
6004                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6005                 if (cache->ro) {
6006                         space_info->bytes_readonly += len;
6007                         readonly = true;
6008                 }
6009                 spin_unlock(&cache->lock);
6010                 if (!readonly && global_rsv->space_info == space_info) {
6011                         spin_lock(&global_rsv->lock);
6012                         if (!global_rsv->full) {
6013                                 len = min(len, global_rsv->size -
6014                                           global_rsv->reserved);
6015                                 global_rsv->reserved += len;
6016                                 space_info->bytes_may_use += len;
6017                                 if (global_rsv->reserved >= global_rsv->size)
6018                                         global_rsv->full = 1;
6019                         }
6020                         spin_unlock(&global_rsv->lock);
6021                 }
6022                 spin_unlock(&space_info->lock);
6023         }
6024
6025         if (cache)
6026                 btrfs_put_block_group(cache);
6027         return 0;
6028 }
6029
6030 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6031                                struct btrfs_root *root)
6032 {
6033         struct btrfs_fs_info *fs_info = root->fs_info;
6034         struct extent_io_tree *unpin;
6035         u64 start;
6036         u64 end;
6037         int ret;
6038
6039         if (trans->aborted)
6040                 return 0;
6041
6042         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6043                 unpin = &fs_info->freed_extents[1];
6044         else
6045                 unpin = &fs_info->freed_extents[0];
6046
6047         while (1) {
6048                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6049                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6050                                             EXTENT_DIRTY, NULL);
6051                 if (ret) {
6052                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6053                         break;
6054                 }
6055
6056                 if (btrfs_test_opt(root, DISCARD))
6057                         ret = btrfs_discard_extent(root, start,
6058                                                    end + 1 - start, NULL);
6059
6060                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
6061                 unpin_extent_range(root, start, end, true);
6062                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6063                 cond_resched();
6064         }
6065
6066         return 0;
6067 }
6068
6069 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6070                              u64 owner, u64 root_objectid)
6071 {
6072         struct btrfs_space_info *space_info;
6073         u64 flags;
6074
6075         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6076                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6077                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
6078                 else
6079                         flags = BTRFS_BLOCK_GROUP_METADATA;
6080         } else {
6081                 flags = BTRFS_BLOCK_GROUP_DATA;
6082         }
6083
6084         space_info = __find_space_info(fs_info, flags);
6085         BUG_ON(!space_info); /* Logic bug */
6086         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6087 }
6088
6089
6090 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6091                                 struct btrfs_root *root,
6092                                 struct btrfs_delayed_ref_node *node, u64 parent,
6093                                 u64 root_objectid, u64 owner_objectid,
6094                                 u64 owner_offset, int refs_to_drop,
6095                                 struct btrfs_delayed_extent_op *extent_op)
6096 {
6097         struct btrfs_key key;
6098         struct btrfs_path *path;
6099         struct btrfs_fs_info *info = root->fs_info;
6100         struct btrfs_root *extent_root = info->extent_root;
6101         struct extent_buffer *leaf;
6102         struct btrfs_extent_item *ei;
6103         struct btrfs_extent_inline_ref *iref;
6104         int ret;
6105         int is_data;
6106         int extent_slot = 0;
6107         int found_extent = 0;
6108         int num_to_del = 1;
6109         int no_quota = node->no_quota;
6110         u32 item_size;
6111         u64 refs;
6112         u64 bytenr = node->bytenr;
6113         u64 num_bytes = node->num_bytes;
6114         int last_ref = 0;
6115         enum btrfs_qgroup_operation_type type = BTRFS_QGROUP_OPER_SUB_EXCL;
6116         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6117                                                  SKINNY_METADATA);
6118
6119         if (!info->quota_enabled || !is_fstree(root_objectid))
6120                 no_quota = 1;
6121
6122         path = btrfs_alloc_path();
6123         if (!path)
6124                 return -ENOMEM;
6125
6126         path->reada = 1;
6127         path->leave_spinning = 1;
6128
6129         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6130         BUG_ON(!is_data && refs_to_drop != 1);
6131
6132         if (is_data)
6133                 skinny_metadata = 0;
6134
6135         ret = lookup_extent_backref(trans, extent_root, path, &iref,
6136                                     bytenr, num_bytes, parent,
6137                                     root_objectid, owner_objectid,
6138                                     owner_offset);
6139         if (ret == 0) {
6140                 extent_slot = path->slots[0];
6141                 while (extent_slot >= 0) {
6142                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6143                                               extent_slot);
6144                         if (key.objectid != bytenr)
6145                                 break;
6146                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6147                             key.offset == num_bytes) {
6148                                 found_extent = 1;
6149                                 break;
6150                         }
6151                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6152                             key.offset == owner_objectid) {
6153                                 found_extent = 1;
6154                                 break;
6155                         }
6156                         if (path->slots[0] - extent_slot > 5)
6157                                 break;
6158                         extent_slot--;
6159                 }
6160 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6161                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6162                 if (found_extent && item_size < sizeof(*ei))
6163                         found_extent = 0;
6164 #endif
6165                 if (!found_extent) {
6166                         BUG_ON(iref);
6167                         ret = remove_extent_backref(trans, extent_root, path,
6168                                                     NULL, refs_to_drop,
6169                                                     is_data, &last_ref);
6170                         if (ret) {
6171                                 btrfs_abort_transaction(trans, extent_root, ret);
6172                                 goto out;
6173                         }
6174                         btrfs_release_path(path);
6175                         path->leave_spinning = 1;
6176
6177                         key.objectid = bytenr;
6178                         key.type = BTRFS_EXTENT_ITEM_KEY;
6179                         key.offset = num_bytes;
6180
6181                         if (!is_data && skinny_metadata) {
6182                                 key.type = BTRFS_METADATA_ITEM_KEY;
6183                                 key.offset = owner_objectid;
6184                         }
6185
6186                         ret = btrfs_search_slot(trans, extent_root,
6187                                                 &key, path, -1, 1);
6188                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6189                                 /*
6190                                  * Couldn't find our skinny metadata item,
6191                                  * see if we have ye olde extent item.
6192                                  */
6193                                 path->slots[0]--;
6194                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6195                                                       path->slots[0]);
6196                                 if (key.objectid == bytenr &&
6197                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6198                                     key.offset == num_bytes)
6199                                         ret = 0;
6200                         }
6201
6202                         if (ret > 0 && skinny_metadata) {
6203                                 skinny_metadata = false;
6204                                 key.objectid = bytenr;
6205                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6206                                 key.offset = num_bytes;
6207                                 btrfs_release_path(path);
6208                                 ret = btrfs_search_slot(trans, extent_root,
6209                                                         &key, path, -1, 1);
6210                         }
6211
6212                         if (ret) {
6213                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6214                                         ret, bytenr);
6215                                 if (ret > 0)
6216                                         btrfs_print_leaf(extent_root,
6217                                                          path->nodes[0]);
6218                         }
6219                         if (ret < 0) {
6220                                 btrfs_abort_transaction(trans, extent_root, ret);
6221                                 goto out;
6222                         }
6223                         extent_slot = path->slots[0];
6224                 }
6225         } else if (WARN_ON(ret == -ENOENT)) {
6226                 btrfs_print_leaf(extent_root, path->nodes[0]);
6227                 btrfs_err(info,
6228                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6229                         bytenr, parent, root_objectid, owner_objectid,
6230                         owner_offset);
6231                 btrfs_abort_transaction(trans, extent_root, ret);
6232                 goto out;
6233         } else {
6234                 btrfs_abort_transaction(trans, extent_root, ret);
6235                 goto out;
6236         }
6237
6238         leaf = path->nodes[0];
6239         item_size = btrfs_item_size_nr(leaf, extent_slot);
6240 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6241         if (item_size < sizeof(*ei)) {
6242                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6243                 ret = convert_extent_item_v0(trans, extent_root, path,
6244                                              owner_objectid, 0);
6245                 if (ret < 0) {
6246                         btrfs_abort_transaction(trans, extent_root, ret);
6247                         goto out;
6248                 }
6249
6250                 btrfs_release_path(path);
6251                 path->leave_spinning = 1;
6252
6253                 key.objectid = bytenr;
6254                 key.type = BTRFS_EXTENT_ITEM_KEY;
6255                 key.offset = num_bytes;
6256
6257                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6258                                         -1, 1);
6259                 if (ret) {
6260                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6261                                 ret, bytenr);
6262                         btrfs_print_leaf(extent_root, path->nodes[0]);
6263                 }
6264                 if (ret < 0) {
6265                         btrfs_abort_transaction(trans, extent_root, ret);
6266                         goto out;
6267                 }
6268
6269                 extent_slot = path->slots[0];
6270                 leaf = path->nodes[0];
6271                 item_size = btrfs_item_size_nr(leaf, extent_slot);
6272         }
6273 #endif
6274         BUG_ON(item_size < sizeof(*ei));
6275         ei = btrfs_item_ptr(leaf, extent_slot,
6276                             struct btrfs_extent_item);
6277         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6278             key.type == BTRFS_EXTENT_ITEM_KEY) {
6279                 struct btrfs_tree_block_info *bi;
6280                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6281                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6282                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6283         }
6284
6285         refs = btrfs_extent_refs(leaf, ei);
6286         if (refs < refs_to_drop) {
6287                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
6288                           "for bytenr %Lu", refs_to_drop, refs, bytenr);
6289                 ret = -EINVAL;
6290                 btrfs_abort_transaction(trans, extent_root, ret);
6291                 goto out;
6292         }
6293         refs -= refs_to_drop;
6294
6295         if (refs > 0) {
6296                 type = BTRFS_QGROUP_OPER_SUB_SHARED;
6297                 if (extent_op)
6298                         __run_delayed_extent_op(extent_op, leaf, ei);
6299                 /*
6300                  * In the case of inline back ref, reference count will
6301                  * be updated by remove_extent_backref
6302                  */
6303                 if (iref) {
6304                         BUG_ON(!found_extent);
6305                 } else {
6306                         btrfs_set_extent_refs(leaf, ei, refs);
6307                         btrfs_mark_buffer_dirty(leaf);
6308                 }
6309                 if (found_extent) {
6310                         ret = remove_extent_backref(trans, extent_root, path,
6311                                                     iref, refs_to_drop,
6312                                                     is_data, &last_ref);
6313                         if (ret) {
6314                                 btrfs_abort_transaction(trans, extent_root, ret);
6315                                 goto out;
6316                         }
6317                 }
6318                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
6319                                  root_objectid);
6320         } else {
6321                 if (found_extent) {
6322                         BUG_ON(is_data && refs_to_drop !=
6323                                extent_data_ref_count(root, path, iref));
6324                         if (iref) {
6325                                 BUG_ON(path->slots[0] != extent_slot);
6326                         } else {
6327                                 BUG_ON(path->slots[0] != extent_slot + 1);
6328                                 path->slots[0] = extent_slot;
6329                                 num_to_del = 2;
6330                         }
6331                 }
6332
6333                 last_ref = 1;
6334                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6335                                       num_to_del);
6336                 if (ret) {
6337                         btrfs_abort_transaction(trans, extent_root, ret);
6338                         goto out;
6339                 }
6340                 btrfs_release_path(path);
6341
6342                 if (is_data) {
6343                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
6344                         if (ret) {
6345                                 btrfs_abort_transaction(trans, extent_root, ret);
6346                                 goto out;
6347                         }
6348                 }
6349
6350                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
6351                 if (ret) {
6352                         btrfs_abort_transaction(trans, extent_root, ret);
6353                         goto out;
6354                 }
6355         }
6356         btrfs_release_path(path);
6357
6358 out:
6359         btrfs_free_path(path);
6360         return ret;
6361 }
6362
6363 /*
6364  * when we free an block, it is possible (and likely) that we free the last
6365  * delayed ref for that extent as well.  This searches the delayed ref tree for
6366  * a given extent, and if there are no other delayed refs to be processed, it
6367  * removes it from the tree.
6368  */
6369 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6370                                       struct btrfs_root *root, u64 bytenr)
6371 {
6372         struct btrfs_delayed_ref_head *head;
6373         struct btrfs_delayed_ref_root *delayed_refs;
6374         int ret = 0;
6375
6376         delayed_refs = &trans->transaction->delayed_refs;
6377         spin_lock(&delayed_refs->lock);
6378         head = btrfs_find_delayed_ref_head(trans, bytenr);
6379         if (!head)
6380                 goto out_delayed_unlock;
6381
6382         spin_lock(&head->lock);
6383         if (!list_empty(&head->ref_list))
6384                 goto out;
6385
6386         if (head->extent_op) {
6387                 if (!head->must_insert_reserved)
6388                         goto out;
6389                 btrfs_free_delayed_extent_op(head->extent_op);
6390                 head->extent_op = NULL;
6391         }
6392
6393         /*
6394          * waiting for the lock here would deadlock.  If someone else has it
6395          * locked they are already in the process of dropping it anyway
6396          */
6397         if (!mutex_trylock(&head->mutex))
6398                 goto out;
6399
6400         /*
6401          * at this point we have a head with no other entries.  Go
6402          * ahead and process it.
6403          */
6404         head->node.in_tree = 0;
6405         rb_erase(&head->href_node, &delayed_refs->href_root);
6406
6407         atomic_dec(&delayed_refs->num_entries);
6408
6409         /*
6410          * we don't take a ref on the node because we're removing it from the
6411          * tree, so we just steal the ref the tree was holding.
6412          */
6413         delayed_refs->num_heads--;
6414         if (head->processing == 0)
6415                 delayed_refs->num_heads_ready--;
6416         head->processing = 0;
6417         spin_unlock(&head->lock);
6418         spin_unlock(&delayed_refs->lock);
6419
6420         BUG_ON(head->extent_op);
6421         if (head->must_insert_reserved)
6422                 ret = 1;
6423
6424         mutex_unlock(&head->mutex);
6425         btrfs_put_delayed_ref(&head->node);
6426         return ret;
6427 out:
6428         spin_unlock(&head->lock);
6429
6430 out_delayed_unlock:
6431         spin_unlock(&delayed_refs->lock);
6432         return 0;
6433 }
6434
6435 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6436                            struct btrfs_root *root,
6437                            struct extent_buffer *buf,
6438                            u64 parent, int last_ref)
6439 {
6440         int pin = 1;
6441         int ret;
6442
6443         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6444                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6445                                         buf->start, buf->len,
6446                                         parent, root->root_key.objectid,
6447                                         btrfs_header_level(buf),
6448                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
6449                 BUG_ON(ret); /* -ENOMEM */
6450         }
6451
6452         if (!last_ref)
6453                 return;
6454
6455         if (btrfs_header_generation(buf) == trans->transid) {
6456                 struct btrfs_block_group_cache *cache;
6457
6458                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6459                         ret = check_ref_cleanup(trans, root, buf->start);
6460                         if (!ret)
6461                                 goto out;
6462                 }
6463
6464                 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6465
6466                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6467                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6468                         btrfs_put_block_group(cache);
6469                         goto out;
6470                 }
6471
6472                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6473
6474                 btrfs_add_free_space(cache, buf->start, buf->len);
6475                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
6476                 btrfs_put_block_group(cache);
6477                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6478                 pin = 0;
6479         }
6480 out:
6481         if (pin)
6482                 add_pinned_bytes(root->fs_info, buf->len,
6483                                  btrfs_header_level(buf),
6484                                  root->root_key.objectid);
6485
6486         /*
6487          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6488          * anymore.
6489          */
6490         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6491 }
6492
6493 /* Can return -ENOMEM */
6494 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6495                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6496                       u64 owner, u64 offset, int no_quota)
6497 {
6498         int ret;
6499         struct btrfs_fs_info *fs_info = root->fs_info;
6500
6501         if (btrfs_test_is_dummy_root(root))
6502                 return 0;
6503
6504         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6505
6506         /*
6507          * tree log blocks never actually go into the extent allocation
6508          * tree, just update pinning info and exit early.
6509          */
6510         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6511                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6512                 /* unlocks the pinned mutex */
6513                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6514                 ret = 0;
6515         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6516                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6517                                         num_bytes,
6518                                         parent, root_objectid, (int)owner,
6519                                         BTRFS_DROP_DELAYED_REF, NULL, no_quota);
6520         } else {
6521                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6522                                                 num_bytes,
6523                                                 parent, root_objectid, owner,
6524                                                 offset, BTRFS_DROP_DELAYED_REF,
6525                                                 NULL, no_quota);
6526         }
6527         return ret;
6528 }
6529
6530 /*
6531  * when we wait for progress in the block group caching, its because
6532  * our allocation attempt failed at least once.  So, we must sleep
6533  * and let some progress happen before we try again.
6534  *
6535  * This function will sleep at least once waiting for new free space to
6536  * show up, and then it will check the block group free space numbers
6537  * for our min num_bytes.  Another option is to have it go ahead
6538  * and look in the rbtree for a free extent of a given size, but this
6539  * is a good start.
6540  *
6541  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6542  * any of the information in this block group.
6543  */
6544 static noinline void
6545 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6546                                 u64 num_bytes)
6547 {
6548         struct btrfs_caching_control *caching_ctl;
6549
6550         caching_ctl = get_caching_control(cache);
6551         if (!caching_ctl)
6552                 return;
6553
6554         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6555                    (cache->free_space_ctl->free_space >= num_bytes));
6556
6557         put_caching_control(caching_ctl);
6558 }
6559
6560 static noinline int
6561 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6562 {
6563         struct btrfs_caching_control *caching_ctl;
6564         int ret = 0;
6565
6566         caching_ctl = get_caching_control(cache);
6567         if (!caching_ctl)
6568                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6569
6570         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6571         if (cache->cached == BTRFS_CACHE_ERROR)
6572                 ret = -EIO;
6573         put_caching_control(caching_ctl);
6574         return ret;
6575 }
6576
6577 int __get_raid_index(u64 flags)
6578 {
6579         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6580                 return BTRFS_RAID_RAID10;
6581         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6582                 return BTRFS_RAID_RAID1;
6583         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6584                 return BTRFS_RAID_DUP;
6585         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6586                 return BTRFS_RAID_RAID0;
6587         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6588                 return BTRFS_RAID_RAID5;
6589         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6590                 return BTRFS_RAID_RAID6;
6591
6592         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6593 }
6594
6595 int get_block_group_index(struct btrfs_block_group_cache *cache)
6596 {
6597         return __get_raid_index(cache->flags);
6598 }
6599
6600 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
6601         [BTRFS_RAID_RAID10]     = "raid10",
6602         [BTRFS_RAID_RAID1]      = "raid1",
6603         [BTRFS_RAID_DUP]        = "dup",
6604         [BTRFS_RAID_RAID0]      = "raid0",
6605         [BTRFS_RAID_SINGLE]     = "single",
6606         [BTRFS_RAID_RAID5]      = "raid5",
6607         [BTRFS_RAID_RAID6]      = "raid6",
6608 };
6609
6610 static const char *get_raid_name(enum btrfs_raid_types type)
6611 {
6612         if (type >= BTRFS_NR_RAID_TYPES)
6613                 return NULL;
6614
6615         return btrfs_raid_type_names[type];
6616 }
6617
6618 enum btrfs_loop_type {
6619         LOOP_CACHING_NOWAIT = 0,
6620         LOOP_CACHING_WAIT = 1,
6621         LOOP_ALLOC_CHUNK = 2,
6622         LOOP_NO_EMPTY_SIZE = 3,
6623 };
6624
6625 static inline void
6626 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
6627                        int delalloc)
6628 {
6629         if (delalloc)
6630                 down_read(&cache->data_rwsem);
6631 }
6632
6633 static inline void
6634 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
6635                        int delalloc)
6636 {
6637         btrfs_get_block_group(cache);
6638         if (delalloc)
6639                 down_read(&cache->data_rwsem);
6640 }
6641
6642 static struct btrfs_block_group_cache *
6643 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
6644                    struct btrfs_free_cluster *cluster,
6645                    int delalloc)
6646 {
6647         struct btrfs_block_group_cache *used_bg;
6648         bool locked = false;
6649 again:
6650         spin_lock(&cluster->refill_lock);
6651         if (locked) {
6652                 if (used_bg == cluster->block_group)
6653                         return used_bg;
6654
6655                 up_read(&used_bg->data_rwsem);
6656                 btrfs_put_block_group(used_bg);
6657         }
6658
6659         used_bg = cluster->block_group;
6660         if (!used_bg)
6661                 return NULL;
6662
6663         if (used_bg == block_group)
6664                 return used_bg;
6665
6666         btrfs_get_block_group(used_bg);
6667
6668         if (!delalloc)
6669                 return used_bg;
6670
6671         if (down_read_trylock(&used_bg->data_rwsem))
6672                 return used_bg;
6673
6674         spin_unlock(&cluster->refill_lock);
6675         down_read(&used_bg->data_rwsem);
6676         locked = true;
6677         goto again;
6678 }
6679
6680 static inline void
6681 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
6682                          int delalloc)
6683 {
6684         if (delalloc)
6685                 up_read(&cache->data_rwsem);
6686         btrfs_put_block_group(cache);
6687 }
6688
6689 /*
6690  * walks the btree of allocated extents and find a hole of a given size.
6691  * The key ins is changed to record the hole:
6692  * ins->objectid == start position
6693  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6694  * ins->offset == the size of the hole.
6695  * Any available blocks before search_start are skipped.
6696  *
6697  * If there is no suitable free space, we will record the max size of
6698  * the free space extent currently.
6699  */
6700 static noinline int find_free_extent(struct btrfs_root *orig_root,
6701                                      u64 num_bytes, u64 empty_size,
6702                                      u64 hint_byte, struct btrfs_key *ins,
6703                                      u64 flags, int delalloc)
6704 {
6705         int ret = 0;
6706         struct btrfs_root *root = orig_root->fs_info->extent_root;
6707         struct btrfs_free_cluster *last_ptr = NULL;
6708         struct btrfs_block_group_cache *block_group = NULL;
6709         u64 search_start = 0;
6710         u64 max_extent_size = 0;
6711         int empty_cluster = 2 * 1024 * 1024;
6712         struct btrfs_space_info *space_info;
6713         int loop = 0;
6714         int index = __get_raid_index(flags);
6715         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6716                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6717         bool failed_cluster_refill = false;
6718         bool failed_alloc = false;
6719         bool use_cluster = true;
6720         bool have_caching_bg = false;
6721
6722         WARN_ON(num_bytes < root->sectorsize);
6723         ins->type = BTRFS_EXTENT_ITEM_KEY;
6724         ins->objectid = 0;
6725         ins->offset = 0;
6726
6727         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6728
6729         space_info = __find_space_info(root->fs_info, flags);
6730         if (!space_info) {
6731                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6732                 return -ENOSPC;
6733         }
6734
6735         /*
6736          * If the space info is for both data and metadata it means we have a
6737          * small filesystem and we can't use the clustering stuff.
6738          */
6739         if (btrfs_mixed_space_info(space_info))
6740                 use_cluster = false;
6741
6742         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6743                 last_ptr = &root->fs_info->meta_alloc_cluster;
6744                 if (!btrfs_test_opt(root, SSD))
6745                         empty_cluster = 64 * 1024;
6746         }
6747
6748         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6749             btrfs_test_opt(root, SSD)) {
6750                 last_ptr = &root->fs_info->data_alloc_cluster;
6751         }
6752
6753         if (last_ptr) {
6754                 spin_lock(&last_ptr->lock);
6755                 if (last_ptr->block_group)
6756                         hint_byte = last_ptr->window_start;
6757                 spin_unlock(&last_ptr->lock);
6758         }
6759
6760         search_start = max(search_start, first_logical_byte(root, 0));
6761         search_start = max(search_start, hint_byte);
6762
6763         if (!last_ptr)
6764                 empty_cluster = 0;
6765
6766         if (search_start == hint_byte) {
6767                 block_group = btrfs_lookup_block_group(root->fs_info,
6768                                                        search_start);
6769                 /*
6770                  * we don't want to use the block group if it doesn't match our
6771                  * allocation bits, or if its not cached.
6772                  *
6773                  * However if we are re-searching with an ideal block group
6774                  * picked out then we don't care that the block group is cached.
6775                  */
6776                 if (block_group && block_group_bits(block_group, flags) &&
6777                     block_group->cached != BTRFS_CACHE_NO) {
6778                         down_read(&space_info->groups_sem);
6779                         if (list_empty(&block_group->list) ||
6780                             block_group->ro) {
6781                                 /*
6782                                  * someone is removing this block group,
6783                                  * we can't jump into the have_block_group
6784                                  * target because our list pointers are not
6785                                  * valid
6786                                  */
6787                                 btrfs_put_block_group(block_group);
6788                                 up_read(&space_info->groups_sem);
6789                         } else {
6790                                 index = get_block_group_index(block_group);
6791                                 btrfs_lock_block_group(block_group, delalloc);
6792                                 goto have_block_group;
6793                         }
6794                 } else if (block_group) {
6795                         btrfs_put_block_group(block_group);
6796                 }
6797         }
6798 search:
6799         have_caching_bg = false;
6800         down_read(&space_info->groups_sem);
6801         list_for_each_entry(block_group, &space_info->block_groups[index],
6802                             list) {
6803                 u64 offset;
6804                 int cached;
6805
6806                 btrfs_grab_block_group(block_group, delalloc);
6807                 search_start = block_group->key.objectid;
6808
6809                 /*
6810                  * this can happen if we end up cycling through all the
6811                  * raid types, but we want to make sure we only allocate
6812                  * for the proper type.
6813                  */
6814                 if (!block_group_bits(block_group, flags)) {
6815                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6816                                 BTRFS_BLOCK_GROUP_RAID1 |
6817                                 BTRFS_BLOCK_GROUP_RAID5 |
6818                                 BTRFS_BLOCK_GROUP_RAID6 |
6819                                 BTRFS_BLOCK_GROUP_RAID10;
6820
6821                         /*
6822                          * if they asked for extra copies and this block group
6823                          * doesn't provide them, bail.  This does allow us to
6824                          * fill raid0 from raid1.
6825                          */
6826                         if ((flags & extra) && !(block_group->flags & extra))
6827                                 goto loop;
6828                 }
6829
6830 have_block_group:
6831                 cached = block_group_cache_done(block_group);
6832                 if (unlikely(!cached)) {
6833                         ret = cache_block_group(block_group, 0);
6834                         BUG_ON(ret < 0);
6835                         ret = 0;
6836                 }
6837
6838                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
6839                         goto loop;
6840                 if (unlikely(block_group->ro))
6841                         goto loop;
6842
6843                 /*
6844                  * Ok we want to try and use the cluster allocator, so
6845                  * lets look there
6846                  */
6847                 if (last_ptr) {
6848                         struct btrfs_block_group_cache *used_block_group;
6849                         unsigned long aligned_cluster;
6850                         /*
6851                          * the refill lock keeps out other
6852                          * people trying to start a new cluster
6853                          */
6854                         used_block_group = btrfs_lock_cluster(block_group,
6855                                                               last_ptr,
6856                                                               delalloc);
6857                         if (!used_block_group)
6858                                 goto refill_cluster;
6859
6860                         if (used_block_group != block_group &&
6861                             (used_block_group->ro ||
6862                              !block_group_bits(used_block_group, flags)))
6863                                 goto release_cluster;
6864
6865                         offset = btrfs_alloc_from_cluster(used_block_group,
6866                                                 last_ptr,
6867                                                 num_bytes,
6868                                                 used_block_group->key.objectid,
6869                                                 &max_extent_size);
6870                         if (offset) {
6871                                 /* we have a block, we're done */
6872                                 spin_unlock(&last_ptr->refill_lock);
6873                                 trace_btrfs_reserve_extent_cluster(root,
6874                                                 used_block_group,
6875                                                 search_start, num_bytes);
6876                                 if (used_block_group != block_group) {
6877                                         btrfs_release_block_group(block_group,
6878                                                                   delalloc);
6879                                         block_group = used_block_group;
6880                                 }
6881                                 goto checks;
6882                         }
6883
6884                         WARN_ON(last_ptr->block_group != used_block_group);
6885 release_cluster:
6886                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6887                          * set up a new clusters, so lets just skip it
6888                          * and let the allocator find whatever block
6889                          * it can find.  If we reach this point, we
6890                          * will have tried the cluster allocator
6891                          * plenty of times and not have found
6892                          * anything, so we are likely way too
6893                          * fragmented for the clustering stuff to find
6894                          * anything.
6895                          *
6896                          * However, if the cluster is taken from the
6897                          * current block group, release the cluster
6898                          * first, so that we stand a better chance of
6899                          * succeeding in the unclustered
6900                          * allocation.  */
6901                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6902                             used_block_group != block_group) {
6903                                 spin_unlock(&last_ptr->refill_lock);
6904                                 btrfs_release_block_group(used_block_group,
6905                                                           delalloc);
6906                                 goto unclustered_alloc;
6907                         }
6908
6909                         /*
6910                          * this cluster didn't work out, free it and
6911                          * start over
6912                          */
6913                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6914
6915                         if (used_block_group != block_group)
6916                                 btrfs_release_block_group(used_block_group,
6917                                                           delalloc);
6918 refill_cluster:
6919                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6920                                 spin_unlock(&last_ptr->refill_lock);
6921                                 goto unclustered_alloc;
6922                         }
6923
6924                         aligned_cluster = max_t(unsigned long,
6925                                                 empty_cluster + empty_size,
6926                                               block_group->full_stripe_len);
6927
6928                         /* allocate a cluster in this block group */
6929                         ret = btrfs_find_space_cluster(root, block_group,
6930                                                        last_ptr, search_start,
6931                                                        num_bytes,
6932                                                        aligned_cluster);
6933                         if (ret == 0) {
6934                                 /*
6935                                  * now pull our allocation out of this
6936                                  * cluster
6937                                  */
6938                                 offset = btrfs_alloc_from_cluster(block_group,
6939                                                         last_ptr,
6940                                                         num_bytes,
6941                                                         search_start,
6942                                                         &max_extent_size);
6943                                 if (offset) {
6944                                         /* we found one, proceed */
6945                                         spin_unlock(&last_ptr->refill_lock);
6946                                         trace_btrfs_reserve_extent_cluster(root,
6947                                                 block_group, search_start,
6948                                                 num_bytes);
6949                                         goto checks;
6950                                 }
6951                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6952                                    && !failed_cluster_refill) {
6953                                 spin_unlock(&last_ptr->refill_lock);
6954
6955                                 failed_cluster_refill = true;
6956                                 wait_block_group_cache_progress(block_group,
6957                                        num_bytes + empty_cluster + empty_size);
6958                                 goto have_block_group;
6959                         }
6960
6961                         /*
6962                          * at this point we either didn't find a cluster
6963                          * or we weren't able to allocate a block from our
6964                          * cluster.  Free the cluster we've been trying
6965                          * to use, and go to the next block group
6966                          */
6967                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6968                         spin_unlock(&last_ptr->refill_lock);
6969                         goto loop;
6970                 }
6971
6972 unclustered_alloc:
6973                 spin_lock(&block_group->free_space_ctl->tree_lock);
6974                 if (cached &&
6975                     block_group->free_space_ctl->free_space <
6976                     num_bytes + empty_cluster + empty_size) {
6977                         if (block_group->free_space_ctl->free_space >
6978                             max_extent_size)
6979                                 max_extent_size =
6980                                         block_group->free_space_ctl->free_space;
6981                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6982                         goto loop;
6983                 }
6984                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6985
6986                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6987                                                     num_bytes, empty_size,
6988                                                     &max_extent_size);
6989                 /*
6990                  * If we didn't find a chunk, and we haven't failed on this
6991                  * block group before, and this block group is in the middle of
6992                  * caching and we are ok with waiting, then go ahead and wait
6993                  * for progress to be made, and set failed_alloc to true.
6994                  *
6995                  * If failed_alloc is true then we've already waited on this
6996                  * block group once and should move on to the next block group.
6997                  */
6998                 if (!offset && !failed_alloc && !cached &&
6999                     loop > LOOP_CACHING_NOWAIT) {
7000                         wait_block_group_cache_progress(block_group,
7001                                                 num_bytes + empty_size);
7002                         failed_alloc = true;
7003                         goto have_block_group;
7004                 } else if (!offset) {
7005                         if (!cached)
7006                                 have_caching_bg = true;
7007                         goto loop;
7008                 }
7009 checks:
7010                 search_start = ALIGN(offset, root->stripesize);
7011
7012                 /* move on to the next group */
7013                 if (search_start + num_bytes >
7014                     block_group->key.objectid + block_group->key.offset) {
7015                         btrfs_add_free_space(block_group, offset, num_bytes);
7016                         goto loop;
7017                 }
7018
7019                 if (offset < search_start)
7020                         btrfs_add_free_space(block_group, offset,
7021                                              search_start - offset);
7022                 BUG_ON(offset > search_start);
7023
7024                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
7025                                                   alloc_type, delalloc);
7026                 if (ret == -EAGAIN) {
7027                         btrfs_add_free_space(block_group, offset, num_bytes);
7028                         goto loop;
7029                 }
7030
7031                 /* we are all good, lets return */
7032                 ins->objectid = search_start;
7033                 ins->offset = num_bytes;
7034
7035                 trace_btrfs_reserve_extent(orig_root, block_group,
7036                                            search_start, num_bytes);
7037                 btrfs_release_block_group(block_group, delalloc);
7038                 break;
7039 loop:
7040                 failed_cluster_refill = false;
7041                 failed_alloc = false;
7042                 BUG_ON(index != get_block_group_index(block_group));
7043                 btrfs_release_block_group(block_group, delalloc);
7044         }
7045         up_read(&space_info->groups_sem);
7046
7047         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7048                 goto search;
7049
7050         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7051                 goto search;
7052
7053         /*
7054          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7055          *                      caching kthreads as we move along
7056          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7057          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7058          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7059          *                      again
7060          */
7061         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7062                 index = 0;
7063                 loop++;
7064                 if (loop == LOOP_ALLOC_CHUNK) {
7065                         struct btrfs_trans_handle *trans;
7066                         int exist = 0;
7067
7068                         trans = current->journal_info;
7069                         if (trans)
7070                                 exist = 1;
7071                         else
7072                                 trans = btrfs_join_transaction(root);
7073
7074                         if (IS_ERR(trans)) {
7075                                 ret = PTR_ERR(trans);
7076                                 goto out;
7077                         }
7078
7079                         ret = do_chunk_alloc(trans, root, flags,
7080                                              CHUNK_ALLOC_FORCE);
7081                         /*
7082                          * Do not bail out on ENOSPC since we
7083                          * can do more things.
7084                          */
7085                         if (ret < 0 && ret != -ENOSPC)
7086                                 btrfs_abort_transaction(trans,
7087                                                         root, ret);
7088                         else
7089                                 ret = 0;
7090                         if (!exist)
7091                                 btrfs_end_transaction(trans, root);
7092                         if (ret)
7093                                 goto out;
7094                 }
7095
7096                 if (loop == LOOP_NO_EMPTY_SIZE) {
7097                         empty_size = 0;
7098                         empty_cluster = 0;
7099                 }
7100
7101                 goto search;
7102         } else if (!ins->objectid) {
7103                 ret = -ENOSPC;
7104         } else if (ins->objectid) {
7105                 ret = 0;
7106         }
7107 out:
7108         if (ret == -ENOSPC)
7109                 ins->offset = max_extent_size;
7110         return ret;
7111 }
7112
7113 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7114                             int dump_block_groups)
7115 {
7116         struct btrfs_block_group_cache *cache;
7117         int index = 0;
7118
7119         spin_lock(&info->lock);
7120         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7121                info->flags,
7122                info->total_bytes - info->bytes_used - info->bytes_pinned -
7123                info->bytes_reserved - info->bytes_readonly,
7124                (info->full) ? "" : "not ");
7125         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7126                "reserved=%llu, may_use=%llu, readonly=%llu\n",
7127                info->total_bytes, info->bytes_used, info->bytes_pinned,
7128                info->bytes_reserved, info->bytes_may_use,
7129                info->bytes_readonly);
7130         spin_unlock(&info->lock);
7131
7132         if (!dump_block_groups)
7133                 return;
7134
7135         down_read(&info->groups_sem);
7136 again:
7137         list_for_each_entry(cache, &info->block_groups[index], list) {
7138                 spin_lock(&cache->lock);
7139                 printk(KERN_INFO "BTRFS: "
7140                            "block group %llu has %llu bytes, "
7141                            "%llu used %llu pinned %llu reserved %s\n",
7142                        cache->key.objectid, cache->key.offset,
7143                        btrfs_block_group_used(&cache->item), cache->pinned,
7144                        cache->reserved, cache->ro ? "[readonly]" : "");
7145                 btrfs_dump_free_space(cache, bytes);
7146                 spin_unlock(&cache->lock);
7147         }
7148         if (++index < BTRFS_NR_RAID_TYPES)
7149                 goto again;
7150         up_read(&info->groups_sem);
7151 }
7152
7153 int btrfs_reserve_extent(struct btrfs_root *root,
7154                          u64 num_bytes, u64 min_alloc_size,
7155                          u64 empty_size, u64 hint_byte,
7156                          struct btrfs_key *ins, int is_data, int delalloc)
7157 {
7158         bool final_tried = false;
7159         u64 flags;
7160         int ret;
7161
7162         flags = btrfs_get_alloc_profile(root, is_data);
7163 again:
7164         WARN_ON(num_bytes < root->sectorsize);
7165         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
7166                                flags, delalloc);
7167
7168         if (ret == -ENOSPC) {
7169                 if (!final_tried && ins->offset) {
7170                         num_bytes = min(num_bytes >> 1, ins->offset);
7171                         num_bytes = round_down(num_bytes, root->sectorsize);
7172                         num_bytes = max(num_bytes, min_alloc_size);
7173                         if (num_bytes == min_alloc_size)
7174                                 final_tried = true;
7175                         goto again;
7176                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7177                         struct btrfs_space_info *sinfo;
7178
7179                         sinfo = __find_space_info(root->fs_info, flags);
7180                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7181                                 flags, num_bytes);
7182                         if (sinfo)
7183                                 dump_space_info(sinfo, num_bytes, 1);
7184                 }
7185         }
7186
7187         return ret;
7188 }
7189
7190 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7191                                         u64 start, u64 len,
7192                                         int pin, int delalloc)
7193 {
7194         struct btrfs_block_group_cache *cache;
7195         int ret = 0;
7196
7197         cache = btrfs_lookup_block_group(root->fs_info, start);
7198         if (!cache) {
7199                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7200                         start);
7201                 return -ENOSPC;
7202         }
7203
7204         if (pin)
7205                 pin_down_extent(root, cache, start, len, 1);
7206         else {
7207                 if (btrfs_test_opt(root, DISCARD))
7208                         ret = btrfs_discard_extent(root, start, len, NULL);
7209                 btrfs_add_free_space(cache, start, len);
7210                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
7211         }
7212
7213         btrfs_put_block_group(cache);
7214
7215         trace_btrfs_reserved_extent_free(root, start, len);
7216
7217         return ret;
7218 }
7219
7220 int btrfs_free_reserved_extent(struct btrfs_root *root,
7221                                u64 start, u64 len, int delalloc)
7222 {
7223         return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
7224 }
7225
7226 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
7227                                        u64 start, u64 len)
7228 {
7229         return __btrfs_free_reserved_extent(root, start, len, 1, 0);
7230 }
7231
7232 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7233                                       struct btrfs_root *root,
7234                                       u64 parent, u64 root_objectid,
7235                                       u64 flags, u64 owner, u64 offset,
7236                                       struct btrfs_key *ins, int ref_mod)
7237 {
7238         int ret;
7239         struct btrfs_fs_info *fs_info = root->fs_info;
7240         struct btrfs_extent_item *extent_item;
7241         struct btrfs_extent_inline_ref *iref;
7242         struct btrfs_path *path;
7243         struct extent_buffer *leaf;
7244         int type;
7245         u32 size;
7246
7247         if (parent > 0)
7248                 type = BTRFS_SHARED_DATA_REF_KEY;
7249         else
7250                 type = BTRFS_EXTENT_DATA_REF_KEY;
7251
7252         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
7253
7254         path = btrfs_alloc_path();
7255         if (!path)
7256                 return -ENOMEM;
7257
7258         path->leave_spinning = 1;
7259         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7260                                       ins, size);
7261         if (ret) {
7262                 btrfs_free_path(path);
7263                 return ret;
7264         }
7265
7266         leaf = path->nodes[0];
7267         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7268                                      struct btrfs_extent_item);
7269         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7270         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7271         btrfs_set_extent_flags(leaf, extent_item,
7272                                flags | BTRFS_EXTENT_FLAG_DATA);
7273
7274         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7275         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7276         if (parent > 0) {
7277                 struct btrfs_shared_data_ref *ref;
7278                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7279                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7280                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7281         } else {
7282                 struct btrfs_extent_data_ref *ref;
7283                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7284                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7285                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7286                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7287                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7288         }
7289
7290         btrfs_mark_buffer_dirty(path->nodes[0]);
7291         btrfs_free_path(path);
7292
7293         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
7294         if (ret) { /* -ENOENT, logic error */
7295                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7296                         ins->objectid, ins->offset);
7297                 BUG();
7298         }
7299         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
7300         return ret;
7301 }
7302
7303 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7304                                      struct btrfs_root *root,
7305                                      u64 parent, u64 root_objectid,
7306                                      u64 flags, struct btrfs_disk_key *key,
7307                                      int level, struct btrfs_key *ins,
7308                                      int no_quota)
7309 {
7310         int ret;
7311         struct btrfs_fs_info *fs_info = root->fs_info;
7312         struct btrfs_extent_item *extent_item;
7313         struct btrfs_tree_block_info *block_info;
7314         struct btrfs_extent_inline_ref *iref;
7315         struct btrfs_path *path;
7316         struct extent_buffer *leaf;
7317         u32 size = sizeof(*extent_item) + sizeof(*iref);
7318         u64 num_bytes = ins->offset;
7319         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7320                                                  SKINNY_METADATA);
7321
7322         if (!skinny_metadata)
7323                 size += sizeof(*block_info);
7324
7325         path = btrfs_alloc_path();
7326         if (!path) {
7327                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7328                                                    root->nodesize);
7329                 return -ENOMEM;
7330         }
7331
7332         path->leave_spinning = 1;
7333         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7334                                       ins, size);
7335         if (ret) {
7336                 btrfs_free_path(path);
7337                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7338                                                    root->nodesize);
7339                 return ret;
7340         }
7341
7342         leaf = path->nodes[0];
7343         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7344                                      struct btrfs_extent_item);
7345         btrfs_set_extent_refs(leaf, extent_item, 1);
7346         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7347         btrfs_set_extent_flags(leaf, extent_item,
7348                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
7349
7350         if (skinny_metadata) {
7351                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7352                 num_bytes = root->nodesize;
7353         } else {
7354                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
7355                 btrfs_set_tree_block_key(leaf, block_info, key);
7356                 btrfs_set_tree_block_level(leaf, block_info, level);
7357                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
7358         }
7359
7360         if (parent > 0) {
7361                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
7362                 btrfs_set_extent_inline_ref_type(leaf, iref,
7363                                                  BTRFS_SHARED_BLOCK_REF_KEY);
7364                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7365         } else {
7366                 btrfs_set_extent_inline_ref_type(leaf, iref,
7367                                                  BTRFS_TREE_BLOCK_REF_KEY);
7368                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
7369         }
7370
7371         btrfs_mark_buffer_dirty(leaf);
7372         btrfs_free_path(path);
7373
7374         ret = update_block_group(trans, root, ins->objectid, root->nodesize,
7375                                  1);
7376         if (ret) { /* -ENOENT, logic error */
7377                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7378                         ins->objectid, ins->offset);
7379                 BUG();
7380         }
7381
7382         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
7383         return ret;
7384 }
7385
7386 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7387                                      struct btrfs_root *root,
7388                                      u64 root_objectid, u64 owner,
7389                                      u64 offset, struct btrfs_key *ins)
7390 {
7391         int ret;
7392
7393         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
7394
7395         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
7396                                          ins->offset, 0,
7397                                          root_objectid, owner, offset,
7398                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
7399         return ret;
7400 }
7401
7402 /*
7403  * this is used by the tree logging recovery code.  It records that
7404  * an extent has been allocated and makes sure to clear the free
7405  * space cache bits as well
7406  */
7407 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
7408                                    struct btrfs_root *root,
7409                                    u64 root_objectid, u64 owner, u64 offset,
7410                                    struct btrfs_key *ins)
7411 {
7412         int ret;
7413         struct btrfs_block_group_cache *block_group;
7414
7415         /*
7416          * Mixed block groups will exclude before processing the log so we only
7417          * need to do the exlude dance if this fs isn't mixed.
7418          */
7419         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
7420                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
7421                 if (ret)
7422                         return ret;
7423         }
7424
7425         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
7426         if (!block_group)
7427                 return -EINVAL;
7428
7429         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
7430                                           RESERVE_ALLOC_NO_ACCOUNT, 0);
7431         BUG_ON(ret); /* logic error */
7432         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
7433                                          0, owner, offset, ins, 1);
7434         btrfs_put_block_group(block_group);
7435         return ret;
7436 }
7437
7438 static struct extent_buffer *
7439 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7440                       u64 bytenr, int level)
7441 {
7442         struct extent_buffer *buf;
7443
7444         buf = btrfs_find_create_tree_block(root, bytenr);
7445         if (!buf)
7446                 return ERR_PTR(-ENOMEM);
7447         btrfs_set_header_generation(buf, trans->transid);
7448         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
7449         btrfs_tree_lock(buf);
7450         clean_tree_block(trans, root->fs_info, buf);
7451         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
7452
7453         btrfs_set_lock_blocking(buf);
7454         btrfs_set_buffer_uptodate(buf);
7455
7456         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
7457                 buf->log_index = root->log_transid % 2;
7458                 /*
7459                  * we allow two log transactions at a time, use different
7460                  * EXENT bit to differentiate dirty pages.
7461                  */
7462                 if (buf->log_index == 0)
7463                         set_extent_dirty(&root->dirty_log_pages, buf->start,
7464                                         buf->start + buf->len - 1, GFP_NOFS);
7465                 else
7466                         set_extent_new(&root->dirty_log_pages, buf->start,
7467                                         buf->start + buf->len - 1, GFP_NOFS);
7468         } else {
7469                 buf->log_index = -1;
7470                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
7471                          buf->start + buf->len - 1, GFP_NOFS);
7472         }
7473         trans->blocks_used++;
7474         /* this returns a buffer locked for blocking */
7475         return buf;
7476 }
7477
7478 static struct btrfs_block_rsv *
7479 use_block_rsv(struct btrfs_trans_handle *trans,
7480               struct btrfs_root *root, u32 blocksize)
7481 {
7482         struct btrfs_block_rsv *block_rsv;
7483         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
7484         int ret;
7485         bool global_updated = false;
7486
7487         block_rsv = get_block_rsv(trans, root);
7488
7489         if (unlikely(block_rsv->size == 0))
7490                 goto try_reserve;
7491 again:
7492         ret = block_rsv_use_bytes(block_rsv, blocksize);
7493         if (!ret)
7494                 return block_rsv;
7495
7496         if (block_rsv->failfast)
7497                 return ERR_PTR(ret);
7498
7499         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
7500                 global_updated = true;
7501                 update_global_block_rsv(root->fs_info);
7502                 goto again;
7503         }
7504
7505         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7506                 static DEFINE_RATELIMIT_STATE(_rs,
7507                                 DEFAULT_RATELIMIT_INTERVAL * 10,
7508                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
7509                 if (__ratelimit(&_rs))
7510                         WARN(1, KERN_DEBUG
7511                                 "BTRFS: block rsv returned %d\n", ret);
7512         }
7513 try_reserve:
7514         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
7515                                      BTRFS_RESERVE_NO_FLUSH);
7516         if (!ret)
7517                 return block_rsv;
7518         /*
7519          * If we couldn't reserve metadata bytes try and use some from
7520          * the global reserve if its space type is the same as the global
7521          * reservation.
7522          */
7523         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
7524             block_rsv->space_info == global_rsv->space_info) {
7525                 ret = block_rsv_use_bytes(global_rsv, blocksize);
7526                 if (!ret)
7527                         return global_rsv;
7528         }
7529         return ERR_PTR(ret);
7530 }
7531
7532 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
7533                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
7534 {
7535         block_rsv_add_bytes(block_rsv, blocksize, 0);
7536         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
7537 }
7538
7539 /*
7540  * finds a free extent and does all the dirty work required for allocation
7541  * returns the key for the extent through ins, and a tree buffer for
7542  * the first block of the extent through buf.
7543  *
7544  * returns the tree buffer or an ERR_PTR on error.
7545  */
7546 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
7547                                         struct btrfs_root *root,
7548                                         u64 parent, u64 root_objectid,
7549                                         struct btrfs_disk_key *key, int level,
7550                                         u64 hint, u64 empty_size)
7551 {
7552         struct btrfs_key ins;
7553         struct btrfs_block_rsv *block_rsv;
7554         struct extent_buffer *buf;
7555         struct btrfs_delayed_extent_op *extent_op;
7556         u64 flags = 0;
7557         int ret;
7558         u32 blocksize = root->nodesize;
7559         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7560                                                  SKINNY_METADATA);
7561
7562         if (btrfs_test_is_dummy_root(root)) {
7563                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
7564                                             level);
7565                 if (!IS_ERR(buf))
7566                         root->alloc_bytenr += blocksize;
7567                 return buf;
7568         }
7569
7570         block_rsv = use_block_rsv(trans, root, blocksize);
7571         if (IS_ERR(block_rsv))
7572                 return ERR_CAST(block_rsv);
7573
7574         ret = btrfs_reserve_extent(root, blocksize, blocksize,
7575                                    empty_size, hint, &ins, 0, 0);
7576         if (ret)
7577                 goto out_unuse;
7578
7579         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
7580         if (IS_ERR(buf)) {
7581                 ret = PTR_ERR(buf);
7582                 goto out_free_reserved;
7583         }
7584
7585         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
7586                 if (parent == 0)
7587                         parent = ins.objectid;
7588                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
7589         } else
7590                 BUG_ON(parent > 0);
7591
7592         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
7593                 extent_op = btrfs_alloc_delayed_extent_op();
7594                 if (!extent_op) {
7595                         ret = -ENOMEM;
7596                         goto out_free_buf;
7597                 }
7598                 if (key)
7599                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
7600                 else
7601                         memset(&extent_op->key, 0, sizeof(extent_op->key));
7602                 extent_op->flags_to_set = flags;
7603                 if (skinny_metadata)
7604                         extent_op->update_key = 0;
7605                 else
7606                         extent_op->update_key = 1;
7607                 extent_op->update_flags = 1;
7608                 extent_op->is_data = 0;
7609                 extent_op->level = level;
7610
7611                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7612                                                  ins.objectid, ins.offset,
7613                                                  parent, root_objectid, level,
7614                                                  BTRFS_ADD_DELAYED_EXTENT,
7615                                                  extent_op, 0);
7616                 if (ret)
7617                         goto out_free_delayed;
7618         }
7619         return buf;
7620
7621 out_free_delayed:
7622         btrfs_free_delayed_extent_op(extent_op);
7623 out_free_buf:
7624         free_extent_buffer(buf);
7625 out_free_reserved:
7626         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
7627 out_unuse:
7628         unuse_block_rsv(root->fs_info, block_rsv, blocksize);
7629         return ERR_PTR(ret);
7630 }
7631
7632 struct walk_control {
7633         u64 refs[BTRFS_MAX_LEVEL];
7634         u64 flags[BTRFS_MAX_LEVEL];
7635         struct btrfs_key update_progress;
7636         int stage;
7637         int level;
7638         int shared_level;
7639         int update_ref;
7640         int keep_locks;
7641         int reada_slot;
7642         int reada_count;
7643         int for_reloc;
7644 };
7645
7646 #define DROP_REFERENCE  1
7647 #define UPDATE_BACKREF  2
7648
7649 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7650                                      struct btrfs_root *root,
7651                                      struct walk_control *wc,
7652                                      struct btrfs_path *path)
7653 {
7654         u64 bytenr;
7655         u64 generation;
7656         u64 refs;
7657         u64 flags;
7658         u32 nritems;
7659         u32 blocksize;
7660         struct btrfs_key key;
7661         struct extent_buffer *eb;
7662         int ret;
7663         int slot;
7664         int nread = 0;
7665
7666         if (path->slots[wc->level] < wc->reada_slot) {
7667                 wc->reada_count = wc->reada_count * 2 / 3;
7668                 wc->reada_count = max(wc->reada_count, 2);
7669         } else {
7670                 wc->reada_count = wc->reada_count * 3 / 2;
7671                 wc->reada_count = min_t(int, wc->reada_count,
7672                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7673         }
7674
7675         eb = path->nodes[wc->level];
7676         nritems = btrfs_header_nritems(eb);
7677         blocksize = root->nodesize;
7678
7679         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7680                 if (nread >= wc->reada_count)
7681                         break;
7682
7683                 cond_resched();
7684                 bytenr = btrfs_node_blockptr(eb, slot);
7685                 generation = btrfs_node_ptr_generation(eb, slot);
7686
7687                 if (slot == path->slots[wc->level])
7688                         goto reada;
7689
7690                 if (wc->stage == UPDATE_BACKREF &&
7691                     generation <= root->root_key.offset)
7692                         continue;
7693
7694                 /* We don't lock the tree block, it's OK to be racy here */
7695                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7696                                                wc->level - 1, 1, &refs,
7697                                                &flags);
7698                 /* We don't care about errors in readahead. */
7699                 if (ret < 0)
7700                         continue;
7701                 BUG_ON(refs == 0);
7702
7703                 if (wc->stage == DROP_REFERENCE) {
7704                         if (refs == 1)
7705                                 goto reada;
7706
7707                         if (wc->level == 1 &&
7708                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7709                                 continue;
7710                         if (!wc->update_ref ||
7711                             generation <= root->root_key.offset)
7712                                 continue;
7713                         btrfs_node_key_to_cpu(eb, &key, slot);
7714                         ret = btrfs_comp_cpu_keys(&key,
7715                                                   &wc->update_progress);
7716                         if (ret < 0)
7717                                 continue;
7718                 } else {
7719                         if (wc->level == 1 &&
7720                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7721                                 continue;
7722                 }
7723 reada:
7724                 readahead_tree_block(root, bytenr);
7725                 nread++;
7726         }
7727         wc->reada_slot = slot;
7728 }
7729
7730 /*
7731  * TODO: Modify related function to add related node/leaf to dirty_extent_root,
7732  * for later qgroup accounting.
7733  *
7734  * Current, this function does nothing.
7735  */
7736 static int account_leaf_items(struct btrfs_trans_handle *trans,
7737                               struct btrfs_root *root,
7738                               struct extent_buffer *eb)
7739 {
7740         int nr = btrfs_header_nritems(eb);
7741         int i, extent_type;
7742         struct btrfs_key key;
7743         struct btrfs_file_extent_item *fi;
7744         u64 bytenr, num_bytes;
7745
7746         for (i = 0; i < nr; i++) {
7747                 btrfs_item_key_to_cpu(eb, &key, i);
7748
7749                 if (key.type != BTRFS_EXTENT_DATA_KEY)
7750                         continue;
7751
7752                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
7753                 /* filter out non qgroup-accountable extents  */
7754                 extent_type = btrfs_file_extent_type(eb, fi);
7755
7756                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
7757                         continue;
7758
7759                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
7760                 if (!bytenr)
7761                         continue;
7762
7763                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
7764         }
7765         return 0;
7766 }
7767
7768 /*
7769  * Walk up the tree from the bottom, freeing leaves and any interior
7770  * nodes which have had all slots visited. If a node (leaf or
7771  * interior) is freed, the node above it will have it's slot
7772  * incremented. The root node will never be freed.
7773  *
7774  * At the end of this function, we should have a path which has all
7775  * slots incremented to the next position for a search. If we need to
7776  * read a new node it will be NULL and the node above it will have the
7777  * correct slot selected for a later read.
7778  *
7779  * If we increment the root nodes slot counter past the number of
7780  * elements, 1 is returned to signal completion of the search.
7781  */
7782 static int adjust_slots_upwards(struct btrfs_root *root,
7783                                 struct btrfs_path *path, int root_level)
7784 {
7785         int level = 0;
7786         int nr, slot;
7787         struct extent_buffer *eb;
7788
7789         if (root_level == 0)
7790                 return 1;
7791
7792         while (level <= root_level) {
7793                 eb = path->nodes[level];
7794                 nr = btrfs_header_nritems(eb);
7795                 path->slots[level]++;
7796                 slot = path->slots[level];
7797                 if (slot >= nr || level == 0) {
7798                         /*
7799                          * Don't free the root -  we will detect this
7800                          * condition after our loop and return a
7801                          * positive value for caller to stop walking the tree.
7802                          */
7803                         if (level != root_level) {
7804                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7805                                 path->locks[level] = 0;
7806
7807                                 free_extent_buffer(eb);
7808                                 path->nodes[level] = NULL;
7809                                 path->slots[level] = 0;
7810                         }
7811                 } else {
7812                         /*
7813                          * We have a valid slot to walk back down
7814                          * from. Stop here so caller can process these
7815                          * new nodes.
7816                          */
7817                         break;
7818                 }
7819
7820                 level++;
7821         }
7822
7823         eb = path->nodes[root_level];
7824         if (path->slots[root_level] >= btrfs_header_nritems(eb))
7825                 return 1;
7826
7827         return 0;
7828 }
7829
7830 /*
7831  * root_eb is the subtree root and is locked before this function is called.
7832  * TODO: Modify this function to mark all (including complete shared node)
7833  * to dirty_extent_root to allow it get accounted in qgroup.
7834  */
7835 static int account_shared_subtree(struct btrfs_trans_handle *trans,
7836                                   struct btrfs_root *root,
7837                                   struct extent_buffer *root_eb,
7838                                   u64 root_gen,
7839                                   int root_level)
7840 {
7841         int ret = 0;
7842         int level;
7843         struct extent_buffer *eb = root_eb;
7844         struct btrfs_path *path = NULL;
7845
7846         BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
7847         BUG_ON(root_eb == NULL);
7848
7849         if (!root->fs_info->quota_enabled)
7850                 return 0;
7851
7852         if (!extent_buffer_uptodate(root_eb)) {
7853                 ret = btrfs_read_buffer(root_eb, root_gen);
7854                 if (ret)
7855                         goto out;
7856         }
7857
7858         if (root_level == 0) {
7859                 ret = account_leaf_items(trans, root, root_eb);
7860                 goto out;
7861         }
7862
7863         path = btrfs_alloc_path();
7864         if (!path)
7865                 return -ENOMEM;
7866
7867         /*
7868          * Walk down the tree.  Missing extent blocks are filled in as
7869          * we go. Metadata is accounted every time we read a new
7870          * extent block.
7871          *
7872          * When we reach a leaf, we account for file extent items in it,
7873          * walk back up the tree (adjusting slot pointers as we go)
7874          * and restart the search process.
7875          */
7876         extent_buffer_get(root_eb); /* For path */
7877         path->nodes[root_level] = root_eb;
7878         path->slots[root_level] = 0;
7879         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
7880 walk_down:
7881         level = root_level;
7882         while (level >= 0) {
7883                 if (path->nodes[level] == NULL) {
7884                         int parent_slot;
7885                         u64 child_gen;
7886                         u64 child_bytenr;
7887
7888                         /* We need to get child blockptr/gen from
7889                          * parent before we can read it. */
7890                         eb = path->nodes[level + 1];
7891                         parent_slot = path->slots[level + 1];
7892                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
7893                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
7894
7895                         eb = read_tree_block(root, child_bytenr, child_gen);
7896                         if (IS_ERR(eb)) {
7897                                 ret = PTR_ERR(eb);
7898                                 goto out;
7899                         } else if (!extent_buffer_uptodate(eb)) {
7900                                 free_extent_buffer(eb);
7901                                 ret = -EIO;
7902                                 goto out;
7903                         }
7904
7905                         path->nodes[level] = eb;
7906                         path->slots[level] = 0;
7907
7908                         btrfs_tree_read_lock(eb);
7909                         btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
7910                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
7911                 }
7912
7913                 if (level == 0) {
7914                         ret = account_leaf_items(trans, root, path->nodes[level]);
7915                         if (ret)
7916                                 goto out;
7917
7918                         /* Nonzero return here means we completed our search */
7919                         ret = adjust_slots_upwards(root, path, root_level);
7920                         if (ret)
7921                                 break;
7922
7923                         /* Restart search with new slots */
7924                         goto walk_down;
7925                 }
7926
7927                 level--;
7928         }
7929
7930         ret = 0;
7931 out:
7932         btrfs_free_path(path);
7933
7934         return ret;
7935 }
7936
7937 /*
7938  * helper to process tree block while walking down the tree.
7939  *
7940  * when wc->stage == UPDATE_BACKREF, this function updates
7941  * back refs for pointers in the block.
7942  *
7943  * NOTE: return value 1 means we should stop walking down.
7944  */
7945 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7946                                    struct btrfs_root *root,
7947                                    struct btrfs_path *path,
7948                                    struct walk_control *wc, int lookup_info)
7949 {
7950         int level = wc->level;
7951         struct extent_buffer *eb = path->nodes[level];
7952         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7953         int ret;
7954
7955         if (wc->stage == UPDATE_BACKREF &&
7956             btrfs_header_owner(eb) != root->root_key.objectid)
7957                 return 1;
7958
7959         /*
7960          * when reference count of tree block is 1, it won't increase
7961          * again. once full backref flag is set, we never clear it.
7962          */
7963         if (lookup_info &&
7964             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7965              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7966                 BUG_ON(!path->locks[level]);
7967                 ret = btrfs_lookup_extent_info(trans, root,
7968                                                eb->start, level, 1,
7969                                                &wc->refs[level],
7970                                                &wc->flags[level]);
7971                 BUG_ON(ret == -ENOMEM);
7972                 if (ret)
7973                         return ret;
7974                 BUG_ON(wc->refs[level] == 0);
7975         }
7976
7977         if (wc->stage == DROP_REFERENCE) {
7978                 if (wc->refs[level] > 1)
7979                         return 1;
7980
7981                 if (path->locks[level] && !wc->keep_locks) {
7982                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7983                         path->locks[level] = 0;
7984                 }
7985                 return 0;
7986         }
7987
7988         /* wc->stage == UPDATE_BACKREF */
7989         if (!(wc->flags[level] & flag)) {
7990                 BUG_ON(!path->locks[level]);
7991                 ret = btrfs_inc_ref(trans, root, eb, 1);
7992                 BUG_ON(ret); /* -ENOMEM */
7993                 ret = btrfs_dec_ref(trans, root, eb, 0);
7994                 BUG_ON(ret); /* -ENOMEM */
7995                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7996                                                   eb->len, flag,
7997                                                   btrfs_header_level(eb), 0);
7998                 BUG_ON(ret); /* -ENOMEM */
7999                 wc->flags[level] |= flag;
8000         }
8001
8002         /*
8003          * the block is shared by multiple trees, so it's not good to
8004          * keep the tree lock
8005          */
8006         if (path->locks[level] && level > 0) {
8007                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8008                 path->locks[level] = 0;
8009         }
8010         return 0;
8011 }
8012
8013 /*
8014  * helper to process tree block pointer.
8015  *
8016  * when wc->stage == DROP_REFERENCE, this function checks
8017  * reference count of the block pointed to. if the block
8018  * is shared and we need update back refs for the subtree
8019  * rooted at the block, this function changes wc->stage to
8020  * UPDATE_BACKREF. if the block is shared and there is no
8021  * need to update back, this function drops the reference
8022  * to the block.
8023  *
8024  * NOTE: return value 1 means we should stop walking down.
8025  */
8026 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8027                                  struct btrfs_root *root,
8028                                  struct btrfs_path *path,
8029                                  struct walk_control *wc, int *lookup_info)
8030 {
8031         u64 bytenr;
8032         u64 generation;
8033         u64 parent;
8034         u32 blocksize;
8035         struct btrfs_key key;
8036         struct extent_buffer *next;
8037         int level = wc->level;
8038         int reada = 0;
8039         int ret = 0;
8040         bool need_account = false;
8041
8042         generation = btrfs_node_ptr_generation(path->nodes[level],
8043                                                path->slots[level]);
8044         /*
8045          * if the lower level block was created before the snapshot
8046          * was created, we know there is no need to update back refs
8047          * for the subtree
8048          */
8049         if (wc->stage == UPDATE_BACKREF &&
8050             generation <= root->root_key.offset) {
8051                 *lookup_info = 1;
8052                 return 1;
8053         }
8054
8055         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8056         blocksize = root->nodesize;
8057
8058         next = btrfs_find_tree_block(root->fs_info, bytenr);
8059         if (!next) {
8060                 next = btrfs_find_create_tree_block(root, bytenr);
8061                 if (!next)
8062                         return -ENOMEM;
8063                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8064                                                level - 1);
8065                 reada = 1;
8066         }
8067         btrfs_tree_lock(next);
8068         btrfs_set_lock_blocking(next);
8069
8070         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8071                                        &wc->refs[level - 1],
8072                                        &wc->flags[level - 1]);
8073         if (ret < 0) {
8074                 btrfs_tree_unlock(next);
8075                 return ret;
8076         }
8077
8078         if (unlikely(wc->refs[level - 1] == 0)) {
8079                 btrfs_err(root->fs_info, "Missing references.");
8080                 BUG();
8081         }
8082         *lookup_info = 0;
8083
8084         if (wc->stage == DROP_REFERENCE) {
8085                 if (wc->refs[level - 1] > 1) {
8086                         need_account = true;
8087                         if (level == 1 &&
8088                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8089                                 goto skip;
8090
8091                         if (!wc->update_ref ||
8092                             generation <= root->root_key.offset)
8093                                 goto skip;
8094
8095                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8096                                               path->slots[level]);
8097                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8098                         if (ret < 0)
8099                                 goto skip;
8100
8101                         wc->stage = UPDATE_BACKREF;
8102                         wc->shared_level = level - 1;
8103                 }
8104         } else {
8105                 if (level == 1 &&
8106                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8107                         goto skip;
8108         }
8109
8110         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8111                 btrfs_tree_unlock(next);
8112                 free_extent_buffer(next);
8113                 next = NULL;
8114                 *lookup_info = 1;
8115         }
8116
8117         if (!next) {
8118                 if (reada && level == 1)
8119                         reada_walk_down(trans, root, wc, path);
8120                 next = read_tree_block(root, bytenr, generation);
8121                 if (IS_ERR(next)) {
8122                         return PTR_ERR(next);
8123                 } else if (!extent_buffer_uptodate(next)) {
8124                         free_extent_buffer(next);
8125                         return -EIO;
8126                 }
8127                 btrfs_tree_lock(next);
8128                 btrfs_set_lock_blocking(next);
8129         }
8130
8131         level--;
8132         BUG_ON(level != btrfs_header_level(next));
8133         path->nodes[level] = next;
8134         path->slots[level] = 0;
8135         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8136         wc->level = level;
8137         if (wc->level == 1)
8138                 wc->reada_slot = 0;
8139         return 0;
8140 skip:
8141         wc->refs[level - 1] = 0;
8142         wc->flags[level - 1] = 0;
8143         if (wc->stage == DROP_REFERENCE) {
8144                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8145                         parent = path->nodes[level]->start;
8146                 } else {
8147                         BUG_ON(root->root_key.objectid !=
8148                                btrfs_header_owner(path->nodes[level]));
8149                         parent = 0;
8150                 }
8151
8152                 if (need_account) {
8153                         ret = account_shared_subtree(trans, root, next,
8154                                                      generation, level - 1);
8155                         if (ret) {
8156                                 printk_ratelimited(KERN_ERR "BTRFS: %s Error "
8157                                         "%d accounting shared subtree. Quota "
8158                                         "is out of sync, rescan required.\n",
8159                                         root->fs_info->sb->s_id, ret);
8160                         }
8161                 }
8162                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8163                                 root->root_key.objectid, level - 1, 0, 0);
8164                 BUG_ON(ret); /* -ENOMEM */
8165         }
8166         btrfs_tree_unlock(next);
8167         free_extent_buffer(next);
8168         *lookup_info = 1;
8169         return 1;
8170 }
8171
8172 /*
8173  * helper to process tree block while walking up the tree.
8174  *
8175  * when wc->stage == DROP_REFERENCE, this function drops
8176  * reference count on the block.
8177  *
8178  * when wc->stage == UPDATE_BACKREF, this function changes
8179  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8180  * to UPDATE_BACKREF previously while processing the block.
8181  *
8182  * NOTE: return value 1 means we should stop walking up.
8183  */
8184 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8185                                  struct btrfs_root *root,
8186                                  struct btrfs_path *path,
8187                                  struct walk_control *wc)
8188 {
8189         int ret;
8190         int level = wc->level;
8191         struct extent_buffer *eb = path->nodes[level];
8192         u64 parent = 0;
8193
8194         if (wc->stage == UPDATE_BACKREF) {
8195                 BUG_ON(wc->shared_level < level);
8196                 if (level < wc->shared_level)
8197                         goto out;
8198
8199                 ret = find_next_key(path, level + 1, &wc->update_progress);
8200                 if (ret > 0)
8201                         wc->update_ref = 0;
8202
8203                 wc->stage = DROP_REFERENCE;
8204                 wc->shared_level = -1;
8205                 path->slots[level] = 0;
8206
8207                 /*
8208                  * check reference count again if the block isn't locked.
8209                  * we should start walking down the tree again if reference
8210                  * count is one.
8211                  */
8212                 if (!path->locks[level]) {
8213                         BUG_ON(level == 0);
8214                         btrfs_tree_lock(eb);
8215                         btrfs_set_lock_blocking(eb);
8216                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8217
8218                         ret = btrfs_lookup_extent_info(trans, root,
8219                                                        eb->start, level, 1,
8220                                                        &wc->refs[level],
8221                                                        &wc->flags[level]);
8222                         if (ret < 0) {
8223                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8224                                 path->locks[level] = 0;
8225                                 return ret;
8226                         }
8227                         BUG_ON(wc->refs[level] == 0);
8228                         if (wc->refs[level] == 1) {
8229                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8230                                 path->locks[level] = 0;
8231                                 return 1;
8232                         }
8233                 }
8234         }
8235
8236         /* wc->stage == DROP_REFERENCE */
8237         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8238
8239         if (wc->refs[level] == 1) {
8240                 if (level == 0) {
8241                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8242                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8243                         else
8244                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8245                         BUG_ON(ret); /* -ENOMEM */
8246                         ret = account_leaf_items(trans, root, eb);
8247                         if (ret) {
8248                                 printk_ratelimited(KERN_ERR "BTRFS: %s Error "
8249                                         "%d accounting leaf items. Quota "
8250                                         "is out of sync, rescan required.\n",
8251                                         root->fs_info->sb->s_id, ret);
8252                         }
8253                 }
8254                 /* make block locked assertion in clean_tree_block happy */
8255                 if (!path->locks[level] &&
8256                     btrfs_header_generation(eb) == trans->transid) {
8257                         btrfs_tree_lock(eb);
8258                         btrfs_set_lock_blocking(eb);
8259                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8260                 }
8261                 clean_tree_block(trans, root->fs_info, eb);
8262         }
8263
8264         if (eb == root->node) {
8265                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8266                         parent = eb->start;
8267                 else
8268                         BUG_ON(root->root_key.objectid !=
8269                                btrfs_header_owner(eb));
8270         } else {
8271                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8272                         parent = path->nodes[level + 1]->start;
8273                 else
8274                         BUG_ON(root->root_key.objectid !=
8275                                btrfs_header_owner(path->nodes[level + 1]));
8276         }
8277
8278         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8279 out:
8280         wc->refs[level] = 0;
8281         wc->flags[level] = 0;
8282         return 0;
8283 }
8284
8285 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8286                                    struct btrfs_root *root,
8287                                    struct btrfs_path *path,
8288                                    struct walk_control *wc)
8289 {
8290         int level = wc->level;
8291         int lookup_info = 1;
8292         int ret;
8293
8294         while (level >= 0) {
8295                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8296                 if (ret > 0)
8297                         break;
8298
8299                 if (level == 0)
8300                         break;
8301
8302                 if (path->slots[level] >=
8303                     btrfs_header_nritems(path->nodes[level]))
8304                         break;
8305
8306                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8307                 if (ret > 0) {
8308                         path->slots[level]++;
8309                         continue;
8310                 } else if (ret < 0)
8311                         return ret;
8312                 level = wc->level;
8313         }
8314         return 0;
8315 }
8316
8317 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8318                                  struct btrfs_root *root,
8319                                  struct btrfs_path *path,
8320                                  struct walk_control *wc, int max_level)
8321 {
8322         int level = wc->level;
8323         int ret;
8324
8325         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8326         while (level < max_level && path->nodes[level]) {
8327                 wc->level = level;
8328                 if (path->slots[level] + 1 <
8329                     btrfs_header_nritems(path->nodes[level])) {
8330                         path->slots[level]++;
8331                         return 0;
8332                 } else {
8333                         ret = walk_up_proc(trans, root, path, wc);
8334                         if (ret > 0)
8335                                 return 0;
8336
8337                         if (path->locks[level]) {
8338                                 btrfs_tree_unlock_rw(path->nodes[level],
8339                                                      path->locks[level]);
8340                                 path->locks[level] = 0;
8341                         }
8342                         free_extent_buffer(path->nodes[level]);
8343                         path->nodes[level] = NULL;
8344                         level++;
8345                 }
8346         }
8347         return 1;
8348 }
8349
8350 /*
8351  * drop a subvolume tree.
8352  *
8353  * this function traverses the tree freeing any blocks that only
8354  * referenced by the tree.
8355  *
8356  * when a shared tree block is found. this function decreases its
8357  * reference count by one. if update_ref is true, this function
8358  * also make sure backrefs for the shared block and all lower level
8359  * blocks are properly updated.
8360  *
8361  * If called with for_reloc == 0, may exit early with -EAGAIN
8362  */
8363 int btrfs_drop_snapshot(struct btrfs_root *root,
8364                          struct btrfs_block_rsv *block_rsv, int update_ref,
8365                          int for_reloc)
8366 {
8367         struct btrfs_path *path;
8368         struct btrfs_trans_handle *trans;
8369         struct btrfs_root *tree_root = root->fs_info->tree_root;
8370         struct btrfs_root_item *root_item = &root->root_item;
8371         struct walk_control *wc;
8372         struct btrfs_key key;
8373         int err = 0;
8374         int ret;
8375         int level;
8376         bool root_dropped = false;
8377
8378         btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
8379
8380         path = btrfs_alloc_path();
8381         if (!path) {
8382                 err = -ENOMEM;
8383                 goto out;
8384         }
8385
8386         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8387         if (!wc) {
8388                 btrfs_free_path(path);
8389                 err = -ENOMEM;
8390                 goto out;
8391         }
8392
8393         trans = btrfs_start_transaction(tree_root, 0);
8394         if (IS_ERR(trans)) {
8395                 err = PTR_ERR(trans);
8396                 goto out_free;
8397         }
8398
8399         if (block_rsv)
8400                 trans->block_rsv = block_rsv;
8401
8402         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8403                 level = btrfs_header_level(root->node);
8404                 path->nodes[level] = btrfs_lock_root_node(root);
8405                 btrfs_set_lock_blocking(path->nodes[level]);
8406                 path->slots[level] = 0;
8407                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8408                 memset(&wc->update_progress, 0,
8409                        sizeof(wc->update_progress));
8410         } else {
8411                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8412                 memcpy(&wc->update_progress, &key,
8413                        sizeof(wc->update_progress));
8414
8415                 level = root_item->drop_level;
8416                 BUG_ON(level == 0);
8417                 path->lowest_level = level;
8418                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8419                 path->lowest_level = 0;
8420                 if (ret < 0) {
8421                         err = ret;
8422                         goto out_end_trans;
8423                 }
8424                 WARN_ON(ret > 0);
8425
8426                 /*
8427                  * unlock our path, this is safe because only this
8428                  * function is allowed to delete this snapshot
8429                  */
8430                 btrfs_unlock_up_safe(path, 0);
8431
8432                 level = btrfs_header_level(root->node);
8433                 while (1) {
8434                         btrfs_tree_lock(path->nodes[level]);
8435                         btrfs_set_lock_blocking(path->nodes[level]);
8436                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8437
8438                         ret = btrfs_lookup_extent_info(trans, root,
8439                                                 path->nodes[level]->start,
8440                                                 level, 1, &wc->refs[level],
8441                                                 &wc->flags[level]);
8442                         if (ret < 0) {
8443                                 err = ret;
8444                                 goto out_end_trans;
8445                         }
8446                         BUG_ON(wc->refs[level] == 0);
8447
8448                         if (level == root_item->drop_level)
8449                                 break;
8450
8451                         btrfs_tree_unlock(path->nodes[level]);
8452                         path->locks[level] = 0;
8453                         WARN_ON(wc->refs[level] != 1);
8454                         level--;
8455                 }
8456         }
8457
8458         wc->level = level;
8459         wc->shared_level = -1;
8460         wc->stage = DROP_REFERENCE;
8461         wc->update_ref = update_ref;
8462         wc->keep_locks = 0;
8463         wc->for_reloc = for_reloc;
8464         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8465
8466         while (1) {
8467
8468                 ret = walk_down_tree(trans, root, path, wc);
8469                 if (ret < 0) {
8470                         err = ret;
8471                         break;
8472                 }
8473
8474                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
8475                 if (ret < 0) {
8476                         err = ret;
8477                         break;
8478                 }
8479
8480                 if (ret > 0) {
8481                         BUG_ON(wc->stage != DROP_REFERENCE);
8482                         break;
8483                 }
8484
8485                 if (wc->stage == DROP_REFERENCE) {
8486                         level = wc->level;
8487                         btrfs_node_key(path->nodes[level],
8488                                        &root_item->drop_progress,
8489                                        path->slots[level]);
8490                         root_item->drop_level = level;
8491                 }
8492
8493                 BUG_ON(wc->level == 0);
8494                 if (btrfs_should_end_transaction(trans, tree_root) ||
8495                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
8496                         ret = btrfs_update_root(trans, tree_root,
8497                                                 &root->root_key,
8498                                                 root_item);
8499                         if (ret) {
8500                                 btrfs_abort_transaction(trans, tree_root, ret);
8501                                 err = ret;
8502                                 goto out_end_trans;
8503                         }
8504
8505                         btrfs_end_transaction_throttle(trans, tree_root);
8506                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
8507                                 pr_debug("BTRFS: drop snapshot early exit\n");
8508                                 err = -EAGAIN;
8509                                 goto out_free;
8510                         }
8511
8512                         trans = btrfs_start_transaction(tree_root, 0);
8513                         if (IS_ERR(trans)) {
8514                                 err = PTR_ERR(trans);
8515                                 goto out_free;
8516                         }
8517                         if (block_rsv)
8518                                 trans->block_rsv = block_rsv;
8519                 }
8520         }
8521         btrfs_release_path(path);
8522         if (err)
8523                 goto out_end_trans;
8524
8525         ret = btrfs_del_root(trans, tree_root, &root->root_key);
8526         if (ret) {
8527                 btrfs_abort_transaction(trans, tree_root, ret);
8528                 goto out_end_trans;
8529         }
8530
8531         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
8532                 ret = btrfs_find_root(tree_root, &root->root_key, path,
8533                                       NULL, NULL);
8534                 if (ret < 0) {
8535                         btrfs_abort_transaction(trans, tree_root, ret);
8536                         err = ret;
8537                         goto out_end_trans;
8538                 } else if (ret > 0) {
8539                         /* if we fail to delete the orphan item this time
8540                          * around, it'll get picked up the next time.
8541                          *
8542                          * The most common failure here is just -ENOENT.
8543                          */
8544                         btrfs_del_orphan_item(trans, tree_root,
8545                                               root->root_key.objectid);
8546                 }
8547         }
8548
8549         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
8550                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
8551         } else {
8552                 free_extent_buffer(root->node);
8553                 free_extent_buffer(root->commit_root);
8554                 btrfs_put_fs_root(root);
8555         }
8556         root_dropped = true;
8557 out_end_trans:
8558         btrfs_end_transaction_throttle(trans, tree_root);
8559 out_free:
8560         kfree(wc);
8561         btrfs_free_path(path);
8562 out:
8563         /*
8564          * So if we need to stop dropping the snapshot for whatever reason we
8565          * need to make sure to add it back to the dead root list so that we
8566          * keep trying to do the work later.  This also cleans up roots if we
8567          * don't have it in the radix (like when we recover after a power fail
8568          * or unmount) so we don't leak memory.
8569          */
8570         if (!for_reloc && root_dropped == false)
8571                 btrfs_add_dead_root(root);
8572         if (err && err != -EAGAIN)
8573                 btrfs_std_error(root->fs_info, err);
8574         return err;
8575 }
8576
8577 /*
8578  * drop subtree rooted at tree block 'node'.
8579  *
8580  * NOTE: this function will unlock and release tree block 'node'
8581  * only used by relocation code
8582  */
8583 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
8584                         struct btrfs_root *root,
8585                         struct extent_buffer *node,
8586                         struct extent_buffer *parent)
8587 {
8588         struct btrfs_path *path;
8589         struct walk_control *wc;
8590         int level;
8591         int parent_level;
8592         int ret = 0;
8593         int wret;
8594
8595         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
8596
8597         path = btrfs_alloc_path();
8598         if (!path)
8599                 return -ENOMEM;
8600
8601         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8602         if (!wc) {
8603                 btrfs_free_path(path);
8604                 return -ENOMEM;
8605         }
8606
8607         btrfs_assert_tree_locked(parent);
8608         parent_level = btrfs_header_level(parent);
8609         extent_buffer_get(parent);
8610         path->nodes[parent_level] = parent;
8611         path->slots[parent_level] = btrfs_header_nritems(parent);
8612
8613         btrfs_assert_tree_locked(node);
8614         level = btrfs_header_level(node);
8615         path->nodes[level] = node;
8616         path->slots[level] = 0;
8617         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8618
8619         wc->refs[parent_level] = 1;
8620         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8621         wc->level = level;
8622         wc->shared_level = -1;
8623         wc->stage = DROP_REFERENCE;
8624         wc->update_ref = 0;
8625         wc->keep_locks = 1;
8626         wc->for_reloc = 1;
8627         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8628
8629         while (1) {
8630                 wret = walk_down_tree(trans, root, path, wc);
8631                 if (wret < 0) {
8632                         ret = wret;
8633                         break;
8634                 }
8635
8636                 wret = walk_up_tree(trans, root, path, wc, parent_level);
8637                 if (wret < 0)
8638                         ret = wret;
8639                 if (wret != 0)
8640                         break;
8641         }
8642
8643         kfree(wc);
8644         btrfs_free_path(path);
8645         return ret;
8646 }
8647
8648 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
8649 {
8650         u64 num_devices;
8651         u64 stripped;
8652
8653         /*
8654          * if restripe for this chunk_type is on pick target profile and
8655          * return, otherwise do the usual balance
8656          */
8657         stripped = get_restripe_target(root->fs_info, flags);
8658         if (stripped)
8659                 return extended_to_chunk(stripped);
8660
8661         num_devices = root->fs_info->fs_devices->rw_devices;
8662
8663         stripped = BTRFS_BLOCK_GROUP_RAID0 |
8664                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
8665                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
8666
8667         if (num_devices == 1) {
8668                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8669                 stripped = flags & ~stripped;
8670
8671                 /* turn raid0 into single device chunks */
8672                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
8673                         return stripped;
8674
8675                 /* turn mirroring into duplication */
8676                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
8677                              BTRFS_BLOCK_GROUP_RAID10))
8678                         return stripped | BTRFS_BLOCK_GROUP_DUP;
8679         } else {
8680                 /* they already had raid on here, just return */
8681                 if (flags & stripped)
8682                         return flags;
8683
8684                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8685                 stripped = flags & ~stripped;
8686
8687                 /* switch duplicated blocks with raid1 */
8688                 if (flags & BTRFS_BLOCK_GROUP_DUP)
8689                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
8690
8691                 /* this is drive concat, leave it alone */
8692         }
8693
8694         return flags;
8695 }
8696
8697 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
8698 {
8699         struct btrfs_space_info *sinfo = cache->space_info;
8700         u64 num_bytes;
8701         u64 min_allocable_bytes;
8702         int ret = -ENOSPC;
8703
8704
8705         /*
8706          * We need some metadata space and system metadata space for
8707          * allocating chunks in some corner cases until we force to set
8708          * it to be readonly.
8709          */
8710         if ((sinfo->flags &
8711              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
8712             !force)
8713                 min_allocable_bytes = 1 * 1024 * 1024;
8714         else
8715                 min_allocable_bytes = 0;
8716
8717         spin_lock(&sinfo->lock);
8718         spin_lock(&cache->lock);
8719
8720         if (cache->ro) {
8721                 ret = 0;
8722                 goto out;
8723         }
8724
8725         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8726                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8727
8728         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
8729             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
8730             min_allocable_bytes <= sinfo->total_bytes) {
8731                 sinfo->bytes_readonly += num_bytes;
8732                 cache->ro = 1;
8733                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
8734                 ret = 0;
8735         }
8736 out:
8737         spin_unlock(&cache->lock);
8738         spin_unlock(&sinfo->lock);
8739         return ret;
8740 }
8741
8742 int btrfs_set_block_group_ro(struct btrfs_root *root,
8743                              struct btrfs_block_group_cache *cache)
8744
8745 {
8746         struct btrfs_trans_handle *trans;
8747         u64 alloc_flags;
8748         int ret;
8749
8750         BUG_ON(cache->ro);
8751
8752 again:
8753         trans = btrfs_join_transaction(root);
8754         if (IS_ERR(trans))
8755                 return PTR_ERR(trans);
8756
8757         /*
8758          * we're not allowed to set block groups readonly after the dirty
8759          * block groups cache has started writing.  If it already started,
8760          * back off and let this transaction commit
8761          */
8762         mutex_lock(&root->fs_info->ro_block_group_mutex);
8763         if (trans->transaction->dirty_bg_run) {
8764                 u64 transid = trans->transid;
8765
8766                 mutex_unlock(&root->fs_info->ro_block_group_mutex);
8767                 btrfs_end_transaction(trans, root);
8768
8769                 ret = btrfs_wait_for_commit(root, transid);
8770                 if (ret)
8771                         return ret;
8772                 goto again;
8773         }
8774
8775         /*
8776          * if we are changing raid levels, try to allocate a corresponding
8777          * block group with the new raid level.
8778          */
8779         alloc_flags = update_block_group_flags(root, cache->flags);
8780         if (alloc_flags != cache->flags) {
8781                 ret = do_chunk_alloc(trans, root, alloc_flags,
8782                                      CHUNK_ALLOC_FORCE);
8783                 /*
8784                  * ENOSPC is allowed here, we may have enough space
8785                  * already allocated at the new raid level to
8786                  * carry on
8787                  */
8788                 if (ret == -ENOSPC)
8789                         ret = 0;
8790                 if (ret < 0)
8791                         goto out;
8792         }
8793
8794         ret = set_block_group_ro(cache, 0);
8795         if (!ret)
8796                 goto out;
8797         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
8798         ret = do_chunk_alloc(trans, root, alloc_flags,
8799                              CHUNK_ALLOC_FORCE);
8800         if (ret < 0)
8801                 goto out;
8802         ret = set_block_group_ro(cache, 0);
8803 out:
8804         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
8805                 alloc_flags = update_block_group_flags(root, cache->flags);
8806                 lock_chunks(root->fs_info->chunk_root);
8807                 check_system_chunk(trans, root, alloc_flags);
8808                 unlock_chunks(root->fs_info->chunk_root);
8809         }
8810         mutex_unlock(&root->fs_info->ro_block_group_mutex);
8811
8812         btrfs_end_transaction(trans, root);
8813         return ret;
8814 }
8815
8816 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
8817                             struct btrfs_root *root, u64 type)
8818 {
8819         u64 alloc_flags = get_alloc_profile(root, type);
8820         return do_chunk_alloc(trans, root, alloc_flags,
8821                               CHUNK_ALLOC_FORCE);
8822 }
8823
8824 /*
8825  * helper to account the unused space of all the readonly block group in the
8826  * space_info. takes mirrors into account.
8827  */
8828 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
8829 {
8830         struct btrfs_block_group_cache *block_group;
8831         u64 free_bytes = 0;
8832         int factor;
8833
8834         /* It's df, we don't care if it's racey */
8835         if (list_empty(&sinfo->ro_bgs))
8836                 return 0;
8837
8838         spin_lock(&sinfo->lock);
8839         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
8840                 spin_lock(&block_group->lock);
8841
8842                 if (!block_group->ro) {
8843                         spin_unlock(&block_group->lock);
8844                         continue;
8845                 }
8846
8847                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
8848                                           BTRFS_BLOCK_GROUP_RAID10 |
8849                                           BTRFS_BLOCK_GROUP_DUP))
8850                         factor = 2;
8851                 else
8852                         factor = 1;
8853
8854                 free_bytes += (block_group->key.offset -
8855                                btrfs_block_group_used(&block_group->item)) *
8856                                factor;
8857
8858                 spin_unlock(&block_group->lock);
8859         }
8860         spin_unlock(&sinfo->lock);
8861
8862         return free_bytes;
8863 }
8864
8865 void btrfs_set_block_group_rw(struct btrfs_root *root,
8866                               struct btrfs_block_group_cache *cache)
8867 {
8868         struct btrfs_space_info *sinfo = cache->space_info;
8869         u64 num_bytes;
8870
8871         BUG_ON(!cache->ro);
8872
8873         spin_lock(&sinfo->lock);
8874         spin_lock(&cache->lock);
8875         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8876                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8877         sinfo->bytes_readonly -= num_bytes;
8878         cache->ro = 0;
8879         list_del_init(&cache->ro_list);
8880         spin_unlock(&cache->lock);
8881         spin_unlock(&sinfo->lock);
8882 }
8883
8884 /*
8885  * checks to see if its even possible to relocate this block group.
8886  *
8887  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
8888  * ok to go ahead and try.
8889  */
8890 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
8891 {
8892         struct btrfs_block_group_cache *block_group;
8893         struct btrfs_space_info *space_info;
8894         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
8895         struct btrfs_device *device;
8896         struct btrfs_trans_handle *trans;
8897         u64 min_free;
8898         u64 dev_min = 1;
8899         u64 dev_nr = 0;
8900         u64 target;
8901         int index;
8902         int full = 0;
8903         int ret = 0;
8904
8905         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
8906
8907         /* odd, couldn't find the block group, leave it alone */
8908         if (!block_group)
8909                 return -1;
8910
8911         min_free = btrfs_block_group_used(&block_group->item);
8912
8913         /* no bytes used, we're good */
8914         if (!min_free)
8915                 goto out;
8916
8917         space_info = block_group->space_info;
8918         spin_lock(&space_info->lock);
8919
8920         full = space_info->full;
8921
8922         /*
8923          * if this is the last block group we have in this space, we can't
8924          * relocate it unless we're able to allocate a new chunk below.
8925          *
8926          * Otherwise, we need to make sure we have room in the space to handle
8927          * all of the extents from this block group.  If we can, we're good
8928          */
8929         if ((space_info->total_bytes != block_group->key.offset) &&
8930             (space_info->bytes_used + space_info->bytes_reserved +
8931              space_info->bytes_pinned + space_info->bytes_readonly +
8932              min_free < space_info->total_bytes)) {
8933                 spin_unlock(&space_info->lock);
8934                 goto out;
8935         }
8936         spin_unlock(&space_info->lock);
8937
8938         /*
8939          * ok we don't have enough space, but maybe we have free space on our
8940          * devices to allocate new chunks for relocation, so loop through our
8941          * alloc devices and guess if we have enough space.  if this block
8942          * group is going to be restriped, run checks against the target
8943          * profile instead of the current one.
8944          */
8945         ret = -1;
8946
8947         /*
8948          * index:
8949          *      0: raid10
8950          *      1: raid1
8951          *      2: dup
8952          *      3: raid0
8953          *      4: single
8954          */
8955         target = get_restripe_target(root->fs_info, block_group->flags);
8956         if (target) {
8957                 index = __get_raid_index(extended_to_chunk(target));
8958         } else {
8959                 /*
8960                  * this is just a balance, so if we were marked as full
8961                  * we know there is no space for a new chunk
8962                  */
8963                 if (full)
8964                         goto out;
8965
8966                 index = get_block_group_index(block_group);
8967         }
8968
8969         if (index == BTRFS_RAID_RAID10) {
8970                 dev_min = 4;
8971                 /* Divide by 2 */
8972                 min_free >>= 1;
8973         } else if (index == BTRFS_RAID_RAID1) {
8974                 dev_min = 2;
8975         } else if (index == BTRFS_RAID_DUP) {
8976                 /* Multiply by 2 */
8977                 min_free <<= 1;
8978         } else if (index == BTRFS_RAID_RAID0) {
8979                 dev_min = fs_devices->rw_devices;
8980                 min_free = div64_u64(min_free, dev_min);
8981         }
8982
8983         /* We need to do this so that we can look at pending chunks */
8984         trans = btrfs_join_transaction(root);
8985         if (IS_ERR(trans)) {
8986                 ret = PTR_ERR(trans);
8987                 goto out;
8988         }
8989
8990         mutex_lock(&root->fs_info->chunk_mutex);
8991         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8992                 u64 dev_offset;
8993
8994                 /*
8995                  * check to make sure we can actually find a chunk with enough
8996                  * space to fit our block group in.
8997                  */
8998                 if (device->total_bytes > device->bytes_used + min_free &&
8999                     !device->is_tgtdev_for_dev_replace) {
9000                         ret = find_free_dev_extent(trans, device, min_free,
9001                                                    &dev_offset, NULL);
9002                         if (!ret)
9003                                 dev_nr++;
9004
9005                         if (dev_nr >= dev_min)
9006                                 break;
9007
9008                         ret = -1;
9009                 }
9010         }
9011         mutex_unlock(&root->fs_info->chunk_mutex);
9012         btrfs_end_transaction(trans, root);
9013 out:
9014         btrfs_put_block_group(block_group);
9015         return ret;
9016 }
9017
9018 static int find_first_block_group(struct btrfs_root *root,
9019                 struct btrfs_path *path, struct btrfs_key *key)
9020 {
9021         int ret = 0;
9022         struct btrfs_key found_key;
9023         struct extent_buffer *leaf;
9024         int slot;
9025
9026         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9027         if (ret < 0)
9028                 goto out;
9029
9030         while (1) {
9031                 slot = path->slots[0];
9032                 leaf = path->nodes[0];
9033                 if (slot >= btrfs_header_nritems(leaf)) {
9034                         ret = btrfs_next_leaf(root, path);
9035                         if (ret == 0)
9036                                 continue;
9037                         if (ret < 0)
9038                                 goto out;
9039                         break;
9040                 }
9041                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9042
9043                 if (found_key.objectid >= key->objectid &&
9044                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9045                         ret = 0;
9046                         goto out;
9047                 }
9048                 path->slots[0]++;
9049         }
9050 out:
9051         return ret;
9052 }
9053
9054 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9055 {
9056         struct btrfs_block_group_cache *block_group;
9057         u64 last = 0;
9058
9059         while (1) {
9060                 struct inode *inode;
9061
9062                 block_group = btrfs_lookup_first_block_group(info, last);
9063                 while (block_group) {
9064                         spin_lock(&block_group->lock);
9065                         if (block_group->iref)
9066                                 break;
9067                         spin_unlock(&block_group->lock);
9068                         block_group = next_block_group(info->tree_root,
9069                                                        block_group);
9070                 }
9071                 if (!block_group) {
9072                         if (last == 0)
9073                                 break;
9074                         last = 0;
9075                         continue;
9076                 }
9077
9078                 inode = block_group->inode;
9079                 block_group->iref = 0;
9080                 block_group->inode = NULL;
9081                 spin_unlock(&block_group->lock);
9082                 iput(inode);
9083                 last = block_group->key.objectid + block_group->key.offset;
9084                 btrfs_put_block_group(block_group);
9085         }
9086 }
9087
9088 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9089 {
9090         struct btrfs_block_group_cache *block_group;
9091         struct btrfs_space_info *space_info;
9092         struct btrfs_caching_control *caching_ctl;
9093         struct rb_node *n;
9094
9095         down_write(&info->commit_root_sem);
9096         while (!list_empty(&info->caching_block_groups)) {
9097                 caching_ctl = list_entry(info->caching_block_groups.next,
9098                                          struct btrfs_caching_control, list);
9099                 list_del(&caching_ctl->list);
9100                 put_caching_control(caching_ctl);
9101         }
9102         up_write(&info->commit_root_sem);
9103
9104         spin_lock(&info->unused_bgs_lock);
9105         while (!list_empty(&info->unused_bgs)) {
9106                 block_group = list_first_entry(&info->unused_bgs,
9107                                                struct btrfs_block_group_cache,
9108                                                bg_list);
9109                 list_del_init(&block_group->bg_list);
9110                 btrfs_put_block_group(block_group);
9111         }
9112         spin_unlock(&info->unused_bgs_lock);
9113
9114         spin_lock(&info->block_group_cache_lock);
9115         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9116                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9117                                        cache_node);
9118                 rb_erase(&block_group->cache_node,
9119                          &info->block_group_cache_tree);
9120                 RB_CLEAR_NODE(&block_group->cache_node);
9121                 spin_unlock(&info->block_group_cache_lock);
9122
9123                 down_write(&block_group->space_info->groups_sem);
9124                 list_del(&block_group->list);
9125                 up_write(&block_group->space_info->groups_sem);
9126
9127                 if (block_group->cached == BTRFS_CACHE_STARTED)
9128                         wait_block_group_cache_done(block_group);
9129
9130                 /*
9131                  * We haven't cached this block group, which means we could
9132                  * possibly have excluded extents on this block group.
9133                  */
9134                 if (block_group->cached == BTRFS_CACHE_NO ||
9135                     block_group->cached == BTRFS_CACHE_ERROR)
9136                         free_excluded_extents(info->extent_root, block_group);
9137
9138                 btrfs_remove_free_space_cache(block_group);
9139                 btrfs_put_block_group(block_group);
9140
9141                 spin_lock(&info->block_group_cache_lock);
9142         }
9143         spin_unlock(&info->block_group_cache_lock);
9144
9145         /* now that all the block groups are freed, go through and
9146          * free all the space_info structs.  This is only called during
9147          * the final stages of unmount, and so we know nobody is
9148          * using them.  We call synchronize_rcu() once before we start,
9149          * just to be on the safe side.
9150          */
9151         synchronize_rcu();
9152
9153         release_global_block_rsv(info);
9154
9155         while (!list_empty(&info->space_info)) {
9156                 int i;
9157
9158                 space_info = list_entry(info->space_info.next,
9159                                         struct btrfs_space_info,
9160                                         list);
9161                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
9162                         if (WARN_ON(space_info->bytes_pinned > 0 ||
9163                             space_info->bytes_reserved > 0 ||
9164                             space_info->bytes_may_use > 0)) {
9165                                 dump_space_info(space_info, 0, 0);
9166                         }
9167                 }
9168                 list_del(&space_info->list);
9169                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9170                         struct kobject *kobj;
9171                         kobj = space_info->block_group_kobjs[i];
9172                         space_info->block_group_kobjs[i] = NULL;
9173                         if (kobj) {
9174                                 kobject_del(kobj);
9175                                 kobject_put(kobj);
9176                         }
9177                 }
9178                 kobject_del(&space_info->kobj);
9179                 kobject_put(&space_info->kobj);
9180         }
9181         return 0;
9182 }
9183
9184 static void __link_block_group(struct btrfs_space_info *space_info,
9185                                struct btrfs_block_group_cache *cache)
9186 {
9187         int index = get_block_group_index(cache);
9188         bool first = false;
9189
9190         down_write(&space_info->groups_sem);
9191         if (list_empty(&space_info->block_groups[index]))
9192                 first = true;
9193         list_add_tail(&cache->list, &space_info->block_groups[index]);
9194         up_write(&space_info->groups_sem);
9195
9196         if (first) {
9197                 struct raid_kobject *rkobj;
9198                 int ret;
9199
9200                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9201                 if (!rkobj)
9202                         goto out_err;
9203                 rkobj->raid_type = index;
9204                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9205                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9206                                   "%s", get_raid_name(index));
9207                 if (ret) {
9208                         kobject_put(&rkobj->kobj);
9209                         goto out_err;
9210                 }
9211                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9212         }
9213
9214         return;
9215 out_err:
9216         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
9217 }
9218
9219 static struct btrfs_block_group_cache *
9220 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
9221 {
9222         struct btrfs_block_group_cache *cache;
9223
9224         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9225         if (!cache)
9226                 return NULL;
9227
9228         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9229                                         GFP_NOFS);
9230         if (!cache->free_space_ctl) {
9231                 kfree(cache);
9232                 return NULL;
9233         }
9234
9235         cache->key.objectid = start;
9236         cache->key.offset = size;
9237         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9238
9239         cache->sectorsize = root->sectorsize;
9240         cache->fs_info = root->fs_info;
9241         cache->full_stripe_len = btrfs_full_stripe_len(root,
9242                                                &root->fs_info->mapping_tree,
9243                                                start);
9244         atomic_set(&cache->count, 1);
9245         spin_lock_init(&cache->lock);
9246         init_rwsem(&cache->data_rwsem);
9247         INIT_LIST_HEAD(&cache->list);
9248         INIT_LIST_HEAD(&cache->cluster_list);
9249         INIT_LIST_HEAD(&cache->bg_list);
9250         INIT_LIST_HEAD(&cache->ro_list);
9251         INIT_LIST_HEAD(&cache->dirty_list);
9252         INIT_LIST_HEAD(&cache->io_list);
9253         btrfs_init_free_space_ctl(cache);
9254         atomic_set(&cache->trimming, 0);
9255
9256         return cache;
9257 }
9258
9259 int btrfs_read_block_groups(struct btrfs_root *root)
9260 {
9261         struct btrfs_path *path;
9262         int ret;
9263         struct btrfs_block_group_cache *cache;
9264         struct btrfs_fs_info *info = root->fs_info;
9265         struct btrfs_space_info *space_info;
9266         struct btrfs_key key;
9267         struct btrfs_key found_key;
9268         struct extent_buffer *leaf;
9269         int need_clear = 0;
9270         u64 cache_gen;
9271
9272         root = info->extent_root;
9273         key.objectid = 0;
9274         key.offset = 0;
9275         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9276         path = btrfs_alloc_path();
9277         if (!path)
9278                 return -ENOMEM;
9279         path->reada = 1;
9280
9281         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
9282         if (btrfs_test_opt(root, SPACE_CACHE) &&
9283             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
9284                 need_clear = 1;
9285         if (btrfs_test_opt(root, CLEAR_CACHE))
9286                 need_clear = 1;
9287
9288         while (1) {
9289                 ret = find_first_block_group(root, path, &key);
9290                 if (ret > 0)
9291                         break;
9292                 if (ret != 0)
9293                         goto error;
9294
9295                 leaf = path->nodes[0];
9296                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9297
9298                 cache = btrfs_create_block_group_cache(root, found_key.objectid,
9299                                                        found_key.offset);
9300                 if (!cache) {
9301                         ret = -ENOMEM;
9302                         goto error;
9303                 }
9304
9305                 if (need_clear) {
9306                         /*
9307                          * When we mount with old space cache, we need to
9308                          * set BTRFS_DC_CLEAR and set dirty flag.
9309                          *
9310                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9311                          *    truncate the old free space cache inode and
9312                          *    setup a new one.
9313                          * b) Setting 'dirty flag' makes sure that we flush
9314                          *    the new space cache info onto disk.
9315                          */
9316                         if (btrfs_test_opt(root, SPACE_CACHE))
9317                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9318                 }
9319
9320                 read_extent_buffer(leaf, &cache->item,
9321                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9322                                    sizeof(cache->item));
9323                 cache->flags = btrfs_block_group_flags(&cache->item);
9324
9325                 key.objectid = found_key.objectid + found_key.offset;
9326                 btrfs_release_path(path);
9327
9328                 /*
9329                  * We need to exclude the super stripes now so that the space
9330                  * info has super bytes accounted for, otherwise we'll think
9331                  * we have more space than we actually do.
9332                  */
9333                 ret = exclude_super_stripes(root, cache);
9334                 if (ret) {
9335                         /*
9336                          * We may have excluded something, so call this just in
9337                          * case.
9338                          */
9339                         free_excluded_extents(root, cache);
9340                         btrfs_put_block_group(cache);
9341                         goto error;
9342                 }
9343
9344                 /*
9345                  * check for two cases, either we are full, and therefore
9346                  * don't need to bother with the caching work since we won't
9347                  * find any space, or we are empty, and we can just add all
9348                  * the space in and be done with it.  This saves us _alot_ of
9349                  * time, particularly in the full case.
9350                  */
9351                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
9352                         cache->last_byte_to_unpin = (u64)-1;
9353                         cache->cached = BTRFS_CACHE_FINISHED;
9354                         free_excluded_extents(root, cache);
9355                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9356                         cache->last_byte_to_unpin = (u64)-1;
9357                         cache->cached = BTRFS_CACHE_FINISHED;
9358                         add_new_free_space(cache, root->fs_info,
9359                                            found_key.objectid,
9360                                            found_key.objectid +
9361                                            found_key.offset);
9362                         free_excluded_extents(root, cache);
9363                 }
9364
9365                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
9366                 if (ret) {
9367                         btrfs_remove_free_space_cache(cache);
9368                         btrfs_put_block_group(cache);
9369                         goto error;
9370                 }
9371
9372                 ret = update_space_info(info, cache->flags, found_key.offset,
9373                                         btrfs_block_group_used(&cache->item),
9374                                         &space_info);
9375                 if (ret) {
9376                         btrfs_remove_free_space_cache(cache);
9377                         spin_lock(&info->block_group_cache_lock);
9378                         rb_erase(&cache->cache_node,
9379                                  &info->block_group_cache_tree);
9380                         RB_CLEAR_NODE(&cache->cache_node);
9381                         spin_unlock(&info->block_group_cache_lock);
9382                         btrfs_put_block_group(cache);
9383                         goto error;
9384                 }
9385
9386                 cache->space_info = space_info;
9387                 spin_lock(&cache->space_info->lock);
9388                 cache->space_info->bytes_readonly += cache->bytes_super;
9389                 spin_unlock(&cache->space_info->lock);
9390
9391                 __link_block_group(space_info, cache);
9392
9393                 set_avail_alloc_bits(root->fs_info, cache->flags);
9394                 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
9395                         set_block_group_ro(cache, 1);
9396                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9397                         spin_lock(&info->unused_bgs_lock);
9398                         /* Should always be true but just in case. */
9399                         if (list_empty(&cache->bg_list)) {
9400                                 btrfs_get_block_group(cache);
9401                                 list_add_tail(&cache->bg_list,
9402                                               &info->unused_bgs);
9403                         }
9404                         spin_unlock(&info->unused_bgs_lock);
9405                 }
9406         }
9407
9408         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
9409                 if (!(get_alloc_profile(root, space_info->flags) &
9410                       (BTRFS_BLOCK_GROUP_RAID10 |
9411                        BTRFS_BLOCK_GROUP_RAID1 |
9412                        BTRFS_BLOCK_GROUP_RAID5 |
9413                        BTRFS_BLOCK_GROUP_RAID6 |
9414                        BTRFS_BLOCK_GROUP_DUP)))
9415                         continue;
9416                 /*
9417                  * avoid allocating from un-mirrored block group if there are
9418                  * mirrored block groups.
9419                  */
9420                 list_for_each_entry(cache,
9421                                 &space_info->block_groups[BTRFS_RAID_RAID0],
9422                                 list)
9423                         set_block_group_ro(cache, 1);
9424                 list_for_each_entry(cache,
9425                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
9426                                 list)
9427                         set_block_group_ro(cache, 1);
9428         }
9429
9430         init_global_block_rsv(info);
9431         ret = 0;
9432 error:
9433         btrfs_free_path(path);
9434         return ret;
9435 }
9436
9437 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
9438                                        struct btrfs_root *root)
9439 {
9440         struct btrfs_block_group_cache *block_group, *tmp;
9441         struct btrfs_root *extent_root = root->fs_info->extent_root;
9442         struct btrfs_block_group_item item;
9443         struct btrfs_key key;
9444         int ret = 0;
9445
9446         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
9447                 if (ret)
9448                         goto next;
9449
9450                 spin_lock(&block_group->lock);
9451                 memcpy(&item, &block_group->item, sizeof(item));
9452                 memcpy(&key, &block_group->key, sizeof(key));
9453                 spin_unlock(&block_group->lock);
9454
9455                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
9456                                         sizeof(item));
9457                 if (ret)
9458                         btrfs_abort_transaction(trans, extent_root, ret);
9459                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
9460                                                key.objectid, key.offset);
9461                 if (ret)
9462                         btrfs_abort_transaction(trans, extent_root, ret);
9463 next:
9464                 list_del_init(&block_group->bg_list);
9465         }
9466 }
9467
9468 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
9469                            struct btrfs_root *root, u64 bytes_used,
9470                            u64 type, u64 chunk_objectid, u64 chunk_offset,
9471                            u64 size)
9472 {
9473         int ret;
9474         struct btrfs_root *extent_root;
9475         struct btrfs_block_group_cache *cache;
9476
9477         extent_root = root->fs_info->extent_root;
9478
9479         btrfs_set_log_full_commit(root->fs_info, trans);
9480
9481         cache = btrfs_create_block_group_cache(root, chunk_offset, size);
9482         if (!cache)
9483                 return -ENOMEM;
9484
9485         btrfs_set_block_group_used(&cache->item, bytes_used);
9486         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
9487         btrfs_set_block_group_flags(&cache->item, type);
9488
9489         cache->flags = type;
9490         cache->last_byte_to_unpin = (u64)-1;
9491         cache->cached = BTRFS_CACHE_FINISHED;
9492         ret = exclude_super_stripes(root, cache);
9493         if (ret) {
9494                 /*
9495                  * We may have excluded something, so call this just in
9496                  * case.
9497                  */
9498                 free_excluded_extents(root, cache);
9499                 btrfs_put_block_group(cache);
9500                 return ret;
9501         }
9502
9503         add_new_free_space(cache, root->fs_info, chunk_offset,
9504                            chunk_offset + size);
9505
9506         free_excluded_extents(root, cache);
9507
9508         /*
9509          * Call to ensure the corresponding space_info object is created and
9510          * assigned to our block group, but don't update its counters just yet.
9511          * We want our bg to be added to the rbtree with its ->space_info set.
9512          */
9513         ret = update_space_info(root->fs_info, cache->flags, 0, 0,
9514                                 &cache->space_info);
9515         if (ret) {
9516                 btrfs_remove_free_space_cache(cache);
9517                 btrfs_put_block_group(cache);
9518                 return ret;
9519         }
9520
9521         ret = btrfs_add_block_group_cache(root->fs_info, cache);
9522         if (ret) {
9523                 btrfs_remove_free_space_cache(cache);
9524                 btrfs_put_block_group(cache);
9525                 return ret;
9526         }
9527
9528         /*
9529          * Now that our block group has its ->space_info set and is inserted in
9530          * the rbtree, update the space info's counters.
9531          */
9532         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
9533                                 &cache->space_info);
9534         if (ret) {
9535                 btrfs_remove_free_space_cache(cache);
9536                 spin_lock(&root->fs_info->block_group_cache_lock);
9537                 rb_erase(&cache->cache_node,
9538                          &root->fs_info->block_group_cache_tree);
9539                 RB_CLEAR_NODE(&cache->cache_node);
9540                 spin_unlock(&root->fs_info->block_group_cache_lock);
9541                 btrfs_put_block_group(cache);
9542                 return ret;
9543         }
9544         update_global_block_rsv(root->fs_info);
9545
9546         spin_lock(&cache->space_info->lock);
9547         cache->space_info->bytes_readonly += cache->bytes_super;
9548         spin_unlock(&cache->space_info->lock);
9549
9550         __link_block_group(cache->space_info, cache);
9551
9552         list_add_tail(&cache->bg_list, &trans->new_bgs);
9553
9554         set_avail_alloc_bits(extent_root->fs_info, type);
9555
9556         return 0;
9557 }
9558
9559 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
9560 {
9561         u64 extra_flags = chunk_to_extended(flags) &
9562                                 BTRFS_EXTENDED_PROFILE_MASK;
9563
9564         write_seqlock(&fs_info->profiles_lock);
9565         if (flags & BTRFS_BLOCK_GROUP_DATA)
9566                 fs_info->avail_data_alloc_bits &= ~extra_flags;
9567         if (flags & BTRFS_BLOCK_GROUP_METADATA)
9568                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
9569         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
9570                 fs_info->avail_system_alloc_bits &= ~extra_flags;
9571         write_sequnlock(&fs_info->profiles_lock);
9572 }
9573
9574 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
9575                              struct btrfs_root *root, u64 group_start,
9576                              struct extent_map *em)
9577 {
9578         struct btrfs_path *path;
9579         struct btrfs_block_group_cache *block_group;
9580         struct btrfs_free_cluster *cluster;
9581         struct btrfs_root *tree_root = root->fs_info->tree_root;
9582         struct btrfs_key key;
9583         struct inode *inode;
9584         struct kobject *kobj = NULL;
9585         int ret;
9586         int index;
9587         int factor;
9588         struct btrfs_caching_control *caching_ctl = NULL;
9589         bool remove_em;
9590
9591         root = root->fs_info->extent_root;
9592
9593         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
9594         BUG_ON(!block_group);
9595         BUG_ON(!block_group->ro);
9596
9597         /*
9598          * Free the reserved super bytes from this block group before
9599          * remove it.
9600          */
9601         free_excluded_extents(root, block_group);
9602
9603         memcpy(&key, &block_group->key, sizeof(key));
9604         index = get_block_group_index(block_group);
9605         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
9606                                   BTRFS_BLOCK_GROUP_RAID1 |
9607                                   BTRFS_BLOCK_GROUP_RAID10))
9608                 factor = 2;
9609         else
9610                 factor = 1;
9611
9612         /* make sure this block group isn't part of an allocation cluster */
9613         cluster = &root->fs_info->data_alloc_cluster;
9614         spin_lock(&cluster->refill_lock);
9615         btrfs_return_cluster_to_free_space(block_group, cluster);
9616         spin_unlock(&cluster->refill_lock);
9617
9618         /*
9619          * make sure this block group isn't part of a metadata
9620          * allocation cluster
9621          */
9622         cluster = &root->fs_info->meta_alloc_cluster;
9623         spin_lock(&cluster->refill_lock);
9624         btrfs_return_cluster_to_free_space(block_group, cluster);
9625         spin_unlock(&cluster->refill_lock);
9626
9627         path = btrfs_alloc_path();
9628         if (!path) {
9629                 ret = -ENOMEM;
9630                 goto out;
9631         }
9632
9633         /*
9634          * get the inode first so any iput calls done for the io_list
9635          * aren't the final iput (no unlinks allowed now)
9636          */
9637         inode = lookup_free_space_inode(tree_root, block_group, path);
9638
9639         mutex_lock(&trans->transaction->cache_write_mutex);
9640         /*
9641          * make sure our free spache cache IO is done before remove the
9642          * free space inode
9643          */
9644         spin_lock(&trans->transaction->dirty_bgs_lock);
9645         if (!list_empty(&block_group->io_list)) {
9646                 list_del_init(&block_group->io_list);
9647
9648                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
9649
9650                 spin_unlock(&trans->transaction->dirty_bgs_lock);
9651                 btrfs_wait_cache_io(root, trans, block_group,
9652                                     &block_group->io_ctl, path,
9653                                     block_group->key.objectid);
9654                 btrfs_put_block_group(block_group);
9655                 spin_lock(&trans->transaction->dirty_bgs_lock);
9656         }
9657
9658         if (!list_empty(&block_group->dirty_list)) {
9659                 list_del_init(&block_group->dirty_list);
9660                 btrfs_put_block_group(block_group);
9661         }
9662         spin_unlock(&trans->transaction->dirty_bgs_lock);
9663         mutex_unlock(&trans->transaction->cache_write_mutex);
9664
9665         if (!IS_ERR(inode)) {
9666                 ret = btrfs_orphan_add(trans, inode);
9667                 if (ret) {
9668                         btrfs_add_delayed_iput(inode);
9669                         goto out;
9670                 }
9671                 clear_nlink(inode);
9672                 /* One for the block groups ref */
9673                 spin_lock(&block_group->lock);
9674                 if (block_group->iref) {
9675                         block_group->iref = 0;
9676                         block_group->inode = NULL;
9677                         spin_unlock(&block_group->lock);
9678                         iput(inode);
9679                 } else {
9680                         spin_unlock(&block_group->lock);
9681                 }
9682                 /* One for our lookup ref */
9683                 btrfs_add_delayed_iput(inode);
9684         }
9685
9686         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
9687         key.offset = block_group->key.objectid;
9688         key.type = 0;
9689
9690         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
9691         if (ret < 0)
9692                 goto out;
9693         if (ret > 0)
9694                 btrfs_release_path(path);
9695         if (ret == 0) {
9696                 ret = btrfs_del_item(trans, tree_root, path);
9697                 if (ret)
9698                         goto out;
9699                 btrfs_release_path(path);
9700         }
9701
9702         spin_lock(&root->fs_info->block_group_cache_lock);
9703         rb_erase(&block_group->cache_node,
9704                  &root->fs_info->block_group_cache_tree);
9705         RB_CLEAR_NODE(&block_group->cache_node);
9706
9707         if (root->fs_info->first_logical_byte == block_group->key.objectid)
9708                 root->fs_info->first_logical_byte = (u64)-1;
9709         spin_unlock(&root->fs_info->block_group_cache_lock);
9710
9711         down_write(&block_group->space_info->groups_sem);
9712         /*
9713          * we must use list_del_init so people can check to see if they
9714          * are still on the list after taking the semaphore
9715          */
9716         list_del_init(&block_group->list);
9717         if (list_empty(&block_group->space_info->block_groups[index])) {
9718                 kobj = block_group->space_info->block_group_kobjs[index];
9719                 block_group->space_info->block_group_kobjs[index] = NULL;
9720                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
9721         }
9722         up_write(&block_group->space_info->groups_sem);
9723         if (kobj) {
9724                 kobject_del(kobj);
9725                 kobject_put(kobj);
9726         }
9727
9728         if (block_group->has_caching_ctl)
9729                 caching_ctl = get_caching_control(block_group);
9730         if (block_group->cached == BTRFS_CACHE_STARTED)
9731                 wait_block_group_cache_done(block_group);
9732         if (block_group->has_caching_ctl) {
9733                 down_write(&root->fs_info->commit_root_sem);
9734                 if (!caching_ctl) {
9735                         struct btrfs_caching_control *ctl;
9736
9737                         list_for_each_entry(ctl,
9738                                     &root->fs_info->caching_block_groups, list)
9739                                 if (ctl->block_group == block_group) {
9740                                         caching_ctl = ctl;
9741                                         atomic_inc(&caching_ctl->count);
9742                                         break;
9743                                 }
9744                 }
9745                 if (caching_ctl)
9746                         list_del_init(&caching_ctl->list);
9747                 up_write(&root->fs_info->commit_root_sem);
9748                 if (caching_ctl) {
9749                         /* Once for the caching bgs list and once for us. */
9750                         put_caching_control(caching_ctl);
9751                         put_caching_control(caching_ctl);
9752                 }
9753         }
9754
9755         spin_lock(&trans->transaction->dirty_bgs_lock);
9756         if (!list_empty(&block_group->dirty_list)) {
9757                 WARN_ON(1);
9758         }
9759         if (!list_empty(&block_group->io_list)) {
9760                 WARN_ON(1);
9761         }
9762         spin_unlock(&trans->transaction->dirty_bgs_lock);
9763         btrfs_remove_free_space_cache(block_group);
9764
9765         spin_lock(&block_group->space_info->lock);
9766         list_del_init(&block_group->ro_list);
9767
9768         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
9769                 WARN_ON(block_group->space_info->total_bytes
9770                         < block_group->key.offset);
9771                 WARN_ON(block_group->space_info->bytes_readonly
9772                         < block_group->key.offset);
9773                 WARN_ON(block_group->space_info->disk_total
9774                         < block_group->key.offset * factor);
9775         }
9776         block_group->space_info->total_bytes -= block_group->key.offset;
9777         block_group->space_info->bytes_readonly -= block_group->key.offset;
9778         block_group->space_info->disk_total -= block_group->key.offset * factor;
9779
9780         spin_unlock(&block_group->space_info->lock);
9781
9782         memcpy(&key, &block_group->key, sizeof(key));
9783
9784         lock_chunks(root);
9785         if (!list_empty(&em->list)) {
9786                 /* We're in the transaction->pending_chunks list. */
9787                 free_extent_map(em);
9788         }
9789         spin_lock(&block_group->lock);
9790         block_group->removed = 1;
9791         /*
9792          * At this point trimming can't start on this block group, because we
9793          * removed the block group from the tree fs_info->block_group_cache_tree
9794          * so no one can't find it anymore and even if someone already got this
9795          * block group before we removed it from the rbtree, they have already
9796          * incremented block_group->trimming - if they didn't, they won't find
9797          * any free space entries because we already removed them all when we
9798          * called btrfs_remove_free_space_cache().
9799          *
9800          * And we must not remove the extent map from the fs_info->mapping_tree
9801          * to prevent the same logical address range and physical device space
9802          * ranges from being reused for a new block group. This is because our
9803          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
9804          * completely transactionless, so while it is trimming a range the
9805          * currently running transaction might finish and a new one start,
9806          * allowing for new block groups to be created that can reuse the same
9807          * physical device locations unless we take this special care.
9808          */
9809         remove_em = (atomic_read(&block_group->trimming) == 0);
9810         /*
9811          * Make sure a trimmer task always sees the em in the pinned_chunks list
9812          * if it sees block_group->removed == 1 (needs to lock block_group->lock
9813          * before checking block_group->removed).
9814          */
9815         if (!remove_em) {
9816                 /*
9817                  * Our em might be in trans->transaction->pending_chunks which
9818                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
9819                  * and so is the fs_info->pinned_chunks list.
9820                  *
9821                  * So at this point we must be holding the chunk_mutex to avoid
9822                  * any races with chunk allocation (more specifically at
9823                  * volumes.c:contains_pending_extent()), to ensure it always
9824                  * sees the em, either in the pending_chunks list or in the
9825                  * pinned_chunks list.
9826                  */
9827                 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
9828         }
9829         spin_unlock(&block_group->lock);
9830
9831         if (remove_em) {
9832                 struct extent_map_tree *em_tree;
9833
9834                 em_tree = &root->fs_info->mapping_tree.map_tree;
9835                 write_lock(&em_tree->lock);
9836                 /*
9837                  * The em might be in the pending_chunks list, so make sure the
9838                  * chunk mutex is locked, since remove_extent_mapping() will
9839                  * delete us from that list.
9840                  */
9841                 remove_extent_mapping(em_tree, em);
9842                 write_unlock(&em_tree->lock);
9843                 /* once for the tree */
9844                 free_extent_map(em);
9845         }
9846
9847         unlock_chunks(root);
9848
9849         btrfs_put_block_group(block_group);
9850         btrfs_put_block_group(block_group);
9851
9852         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
9853         if (ret > 0)
9854                 ret = -EIO;
9855         if (ret < 0)
9856                 goto out;
9857
9858         ret = btrfs_del_item(trans, root, path);
9859 out:
9860         btrfs_free_path(path);
9861         return ret;
9862 }
9863
9864 /*
9865  * Process the unused_bgs list and remove any that don't have any allocated
9866  * space inside of them.
9867  */
9868 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
9869 {
9870         struct btrfs_block_group_cache *block_group;
9871         struct btrfs_space_info *space_info;
9872         struct btrfs_root *root = fs_info->extent_root;
9873         struct btrfs_trans_handle *trans;
9874         int ret = 0;
9875
9876         if (!fs_info->open)
9877                 return;
9878
9879         spin_lock(&fs_info->unused_bgs_lock);
9880         while (!list_empty(&fs_info->unused_bgs)) {
9881                 u64 start, end;
9882
9883                 block_group = list_first_entry(&fs_info->unused_bgs,
9884                                                struct btrfs_block_group_cache,
9885                                                bg_list);
9886                 space_info = block_group->space_info;
9887                 list_del_init(&block_group->bg_list);
9888                 if (ret || btrfs_mixed_space_info(space_info)) {
9889                         btrfs_put_block_group(block_group);
9890                         continue;
9891                 }
9892                 spin_unlock(&fs_info->unused_bgs_lock);
9893
9894                 /* Don't want to race with allocators so take the groups_sem */
9895                 down_write(&space_info->groups_sem);
9896                 spin_lock(&block_group->lock);
9897                 if (block_group->reserved ||
9898                     btrfs_block_group_used(&block_group->item) ||
9899                     block_group->ro) {
9900                         /*
9901                          * We want to bail if we made new allocations or have
9902                          * outstanding allocations in this block group.  We do
9903                          * the ro check in case balance is currently acting on
9904                          * this block group.
9905                          */
9906                         spin_unlock(&block_group->lock);
9907                         up_write(&space_info->groups_sem);
9908                         goto next;
9909                 }
9910                 spin_unlock(&block_group->lock);
9911
9912                 /* We don't want to force the issue, only flip if it's ok. */
9913                 ret = set_block_group_ro(block_group, 0);
9914                 up_write(&space_info->groups_sem);
9915                 if (ret < 0) {
9916                         ret = 0;
9917                         goto next;
9918                 }
9919
9920                 /*
9921                  * Want to do this before we do anything else so we can recover
9922                  * properly if we fail to join the transaction.
9923                  */
9924                 /* 1 for btrfs_orphan_reserve_metadata() */
9925                 trans = btrfs_start_transaction(root, 1);
9926                 if (IS_ERR(trans)) {
9927                         btrfs_set_block_group_rw(root, block_group);
9928                         ret = PTR_ERR(trans);
9929                         goto next;
9930                 }
9931
9932                 /*
9933                  * We could have pending pinned extents for this block group,
9934                  * just delete them, we don't care about them anymore.
9935                  */
9936                 start = block_group->key.objectid;
9937                 end = start + block_group->key.offset - 1;
9938                 /*
9939                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
9940                  * btrfs_finish_extent_commit(). If we are at transaction N,
9941                  * another task might be running finish_extent_commit() for the
9942                  * previous transaction N - 1, and have seen a range belonging
9943                  * to the block group in freed_extents[] before we were able to
9944                  * clear the whole block group range from freed_extents[]. This
9945                  * means that task can lookup for the block group after we
9946                  * unpinned it from freed_extents[] and removed it, leading to
9947                  * a BUG_ON() at btrfs_unpin_extent_range().
9948                  */
9949                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
9950                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
9951                                   EXTENT_DIRTY, GFP_NOFS);
9952                 if (ret) {
9953                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
9954                         btrfs_set_block_group_rw(root, block_group);
9955                         goto end_trans;
9956                 }
9957                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
9958                                   EXTENT_DIRTY, GFP_NOFS);
9959                 if (ret) {
9960                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
9961                         btrfs_set_block_group_rw(root, block_group);
9962                         goto end_trans;
9963                 }
9964                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
9965
9966                 /* Reset pinned so btrfs_put_block_group doesn't complain */
9967                 spin_lock(&space_info->lock);
9968                 spin_lock(&block_group->lock);
9969
9970                 space_info->bytes_pinned -= block_group->pinned;
9971                 space_info->bytes_readonly += block_group->pinned;
9972                 percpu_counter_add(&space_info->total_bytes_pinned,
9973                                    -block_group->pinned);
9974                 block_group->pinned = 0;
9975
9976                 spin_unlock(&block_group->lock);
9977                 spin_unlock(&space_info->lock);
9978
9979                 /*
9980                  * Btrfs_remove_chunk will abort the transaction if things go
9981                  * horribly wrong.
9982                  */
9983                 ret = btrfs_remove_chunk(trans, root,
9984                                          block_group->key.objectid);
9985 end_trans:
9986                 btrfs_end_transaction(trans, root);
9987 next:
9988                 btrfs_put_block_group(block_group);
9989                 spin_lock(&fs_info->unused_bgs_lock);
9990         }
9991         spin_unlock(&fs_info->unused_bgs_lock);
9992 }
9993
9994 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
9995 {
9996         struct btrfs_space_info *space_info;
9997         struct btrfs_super_block *disk_super;
9998         u64 features;
9999         u64 flags;
10000         int mixed = 0;
10001         int ret;
10002
10003         disk_super = fs_info->super_copy;
10004         if (!btrfs_super_root(disk_super))
10005                 return 1;
10006
10007         features = btrfs_super_incompat_flags(disk_super);
10008         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10009                 mixed = 1;
10010
10011         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10012         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10013         if (ret)
10014                 goto out;
10015
10016         if (mixed) {
10017                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10018                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10019         } else {
10020                 flags = BTRFS_BLOCK_GROUP_METADATA;
10021                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10022                 if (ret)
10023                         goto out;
10024
10025                 flags = BTRFS_BLOCK_GROUP_DATA;
10026                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10027         }
10028 out:
10029         return ret;
10030 }
10031
10032 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10033 {
10034         return unpin_extent_range(root, start, end, false);
10035 }
10036
10037 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
10038 {
10039         struct btrfs_fs_info *fs_info = root->fs_info;
10040         struct btrfs_block_group_cache *cache = NULL;
10041         u64 group_trimmed;
10042         u64 start;
10043         u64 end;
10044         u64 trimmed = 0;
10045         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10046         int ret = 0;
10047
10048         /*
10049          * try to trim all FS space, our block group may start from non-zero.
10050          */
10051         if (range->len == total_bytes)
10052                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10053         else
10054                 cache = btrfs_lookup_block_group(fs_info, range->start);
10055
10056         while (cache) {
10057                 if (cache->key.objectid >= (range->start + range->len)) {
10058                         btrfs_put_block_group(cache);
10059                         break;
10060                 }
10061
10062                 start = max(range->start, cache->key.objectid);
10063                 end = min(range->start + range->len,
10064                                 cache->key.objectid + cache->key.offset);
10065
10066                 if (end - start >= range->minlen) {
10067                         if (!block_group_cache_done(cache)) {
10068                                 ret = cache_block_group(cache, 0);
10069                                 if (ret) {
10070                                         btrfs_put_block_group(cache);
10071                                         break;
10072                                 }
10073                                 ret = wait_block_group_cache_done(cache);
10074                                 if (ret) {
10075                                         btrfs_put_block_group(cache);
10076                                         break;
10077                                 }
10078                         }
10079                         ret = btrfs_trim_block_group(cache,
10080                                                      &group_trimmed,
10081                                                      start,
10082                                                      end,
10083                                                      range->minlen);
10084
10085                         trimmed += group_trimmed;
10086                         if (ret) {
10087                                 btrfs_put_block_group(cache);
10088                                 break;
10089                         }
10090                 }
10091
10092                 cache = next_block_group(fs_info->tree_root, cache);
10093         }
10094
10095         range->len = trimmed;
10096         return ret;
10097 }
10098
10099 /*
10100  * btrfs_{start,end}_write_no_snapshoting() are similar to
10101  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10102  * data into the page cache through nocow before the subvolume is snapshoted,
10103  * but flush the data into disk after the snapshot creation, or to prevent
10104  * operations while snapshoting is ongoing and that cause the snapshot to be
10105  * inconsistent (writes followed by expanding truncates for example).
10106  */
10107 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
10108 {
10109         percpu_counter_dec(&root->subv_writers->counter);
10110         /*
10111          * Make sure counter is updated before we wake up
10112          * waiters.
10113          */
10114         smp_mb();
10115         if (waitqueue_active(&root->subv_writers->wait))
10116                 wake_up(&root->subv_writers->wait);
10117 }
10118
10119 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
10120 {
10121         if (atomic_read(&root->will_be_snapshoted))
10122                 return 0;
10123
10124         percpu_counter_inc(&root->subv_writers->counter);
10125         /*
10126          * Make sure counter is updated before we check for snapshot creation.
10127          */
10128         smp_mb();
10129         if (atomic_read(&root->will_be_snapshoted)) {
10130                 btrfs_end_write_no_snapshoting(root);
10131                 return 0;
10132         }
10133         return 1;
10134 }