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                                 u64 bytenr, u64 num_bytes, 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                                 int no_quota);
  87 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  88                                     struct extent_buffer *leaf,
  89                                     struct btrfs_extent_item *ei);
  90 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  91                                       struct btrfs_root *root,
  92                                       u64 parent, u64 root_objectid,
  93                                       u64 flags, u64 owner, u64 offset,
  94                                       struct btrfs_key *ins, int ref_mod);
  95 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  96                                      struct btrfs_root *root,
  97                                      u64 parent, u64 root_objectid,
  98                                      u64 flags, struct btrfs_disk_key *key,
  99                                      int level, struct btrfs_key *ins,
 100                                      int no_quota);
 101 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 102                           struct btrfs_root *extent_root, u64 flags,
 103                           int force);
 104 static int find_next_key(struct btrfs_path *path, int level,
 105                          struct btrfs_key *key);
 106 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 107                             int dump_block_groups);
 108 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 109                                        u64 num_bytes, int reserve,
 110                                        int delalloc);
 111 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 112                                u64 num_bytes);
 113 int btrfs_pin_extent(struct btrfs_root *root,
 114                      u64 bytenr, u64 num_bytes, int reserved);
 115
 116 static noinline int
 117 block_group_cache_done(struct btrfs_block_group_cache *cache)
 118 {
 119         smp_mb();
 120         return cache->cached == BTRFS_CACHE_FINISHED ||
 121                 cache->cached == BTRFS_CACHE_ERROR;
 122 }
 123
 124 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 125 {
 126         return (cache->flags & bits) == bits;
 127 }
 128
 129 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 130 {
 131         atomic_inc(&cache->count);
 132 }
 133
 134 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 135 {
 136         if (atomic_dec_and_test(&cache->count)) {
 137                 WARN_ON(cache->pinned > 0);
 138                 WARN_ON(cache->reserved > 0);
 139                 kfree(cache->free_space_ctl);
 140                 kfree(cache);
 141         }
 142 }
 143
 144 /*
 145  * this adds the block group to the fs_info rb tree for the block group
 146  * cache
 147  */
 148 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 149                                 struct btrfs_block_group_cache *block_group)
 150 {
 151         struct rb_node **p;
 152         struct rb_node *parent = NULL;
 153         struct btrfs_block_group_cache *cache;
 154
 155         spin_lock(&info->block_group_cache_lock);
 156         p = &info->block_group_cache_tree.rb_node;
 157
 158         while (*p) {
 159                 parent = *p;
 160                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 161                                  cache_node);
 162                 if (block_group->key.objectid < cache->key.objectid) {
 163                         p = &(*p)->rb_left;
 164                 } else if (block_group->key.objectid > cache->key.objectid) {
 165                         p = &(*p)->rb_right;
 166                 } else {
 167                         spin_unlock(&info->block_group_cache_lock);
 168                         return -EEXIST;
 169                 }
 170         }
 171
 172         rb_link_node(&block_group->cache_node, parent, p);
 173         rb_insert_color(&block_group->cache_node,
 174                         &info->block_group_cache_tree);
 175
 176         if (info->first_logical_byte > block_group->key.objectid)
 177                 info->first_logical_byte = block_group->key.objectid;
 178
 179         spin_unlock(&info->block_group_cache_lock);
 180
 181         return 0;
 182 }
 183
 184 /*
 185  * This will return the block group at or after bytenr if contains is 0, else
 186  * it will return the block group that contains the bytenr
 187  */
 188 static struct btrfs_block_group_cache *
 189 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 190                               int contains)
 191 {
 192         struct btrfs_block_group_cache *cache, *ret = NULL;
 193         struct rb_node *n;
 194         u64 end, start;
 195
 196         spin_lock(&info->block_group_cache_lock);
 197         n = info->block_group_cache_tree.rb_node;
 198
 199         while (n) {
 200                 cache = rb_entry(n, struct btrfs_block_group_cache,
 201                                  cache_node);
 202                 end = cache->key.objectid + cache->key.offset - 1;
 203                 start = cache->key.objectid;
 204
 205                 if (bytenr < start) {
 206                         if (!contains && (!ret || start < ret->key.objectid))
 207                                 ret = cache;
 208                         n = n->rb_left;
 209                 } else if (bytenr > start) {
 210                         if (contains && bytenr <= end) {
 211                                 ret = cache;
 212                                 break;
 213                         }
 214                         n = n->rb_right;
 215                 } else {
 216                         ret = cache;
 217                         break;
 218                 }
 219         }
 220         if (ret) {
 221                 btrfs_get_block_group(ret);
 222                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 223                         info->first_logical_byte = ret->key.objectid;
 224         }
 225         spin_unlock(&info->block_group_cache_lock);
 226
 227         return ret;
 228 }
 229
 230 static int add_excluded_extent(struct btrfs_root *root,
 231                                u64 start, u64 num_bytes)
 232 {
 233         u64 end = start + num_bytes - 1;
 234         set_extent_bits(&root->fs_info->freed_extents[0],
 235                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 236         set_extent_bits(&root->fs_info->freed_extents[1],
 237                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 238         return 0;
 239 }
 240
 241 static void free_excluded_extents(struct btrfs_root *root,
 242                                   struct btrfs_block_group_cache *cache)
 243 {
 244         u64 start, end;
 245
 246         start = cache->key.objectid;
 247         end = start + cache->key.offset - 1;
 248
 249         clear_extent_bits(&root->fs_info->freed_extents[0],
 250                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 251         clear_extent_bits(&root->fs_info->freed_extents[1],
 252                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 253 }
 254
 255 static int exclude_super_stripes(struct btrfs_root *root,
 256                                  struct btrfs_block_group_cache *cache)
 257 {
 258         u64 bytenr;
 259         u64 *logical;
 260         int stripe_len;
 261         int i, nr, ret;
 262
 263         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 264                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 265                 cache->bytes_super += stripe_len;
 266                 ret = add_excluded_extent(root, cache->key.objectid,
 267                                           stripe_len);
 268                 if (ret)
 269                         return ret;
 270         }
 271
 272         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 273                 bytenr = btrfs_sb_offset(i);
 274                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 275                                        cache->key.objectid, bytenr,
 276                                        0, &logical, &nr, &stripe_len);
 277                 if (ret)
 278                         return ret;
 279
 280                 while (nr--) {
 281                         u64 start, len;
 282
 283                         if (logical[nr] > cache->key.objectid +
 284                             cache->key.offset)
 285                                 continue;
 286
 287                         if (logical[nr] + stripe_len <= cache->key.objectid)
 288                                 continue;
 289
 290                         start = logical[nr];
 291                         if (start < cache->key.objectid) {
 292                                 start = cache->key.objectid;
 293                                 len = (logical[nr] + stripe_len) - start;
 294                         } else {
 295                                 len = min_t(u64, stripe_len,
 296                                             cache->key.objectid +
 297                                             cache->key.offset - start);
 298                         }
 299
 300                         cache->bytes_super += len;
 301                         ret = add_excluded_extent(root, start, len);
 302                         if (ret) {
 303                                 kfree(logical);
 304                                 return ret;
 305                         }
 306                 }
 307
 308                 kfree(logical);
 309         }
 310         return 0;
 311 }
 312
 313 static struct btrfs_caching_control *
 314 get_caching_control(struct btrfs_block_group_cache *cache)
 315 {
 316         struct btrfs_caching_control *ctl;
 317
 318         spin_lock(&cache->lock);
 319         if (!cache->caching_ctl) {
 320                 spin_unlock(&cache->lock);
 321                 return NULL;
 322         }
 323
 324         ctl = cache->caching_ctl;
 325         atomic_inc(&ctl->count);
 326         spin_unlock(&cache->lock);
 327         return ctl;
 328 }
 329
 330 static void put_caching_control(struct btrfs_caching_control *ctl)
 331 {
 332         if (atomic_dec_and_test(&ctl->count))
 333                 kfree(ctl);
 334 }
 335
 336 /*
 337  * this is only called by cache_block_group, since we could have freed extents
 338  * we need to check the pinned_extents for any extents that can't be used yet
 339  * since their free space will be released as soon as the transaction commits.
 340  */
 341 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 342                               struct btrfs_fs_info *info, u64 start, u64 end)
 343 {
 344         u64 extent_start, extent_end, size, total_added = 0;
 345         int ret;
 346
 347         while (start < end) {
 348                 ret = find_first_extent_bit(info->pinned_extents, start,
 349                                             &extent_start, &extent_end,
 350                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 351                                             NULL);
 352                 if (ret)
 353                         break;
 354
 355                 if (extent_start <= start) {
 356                         start = extent_end + 1;
 357                 } else if (extent_start > start && extent_start < end) {
 358                         size = extent_start - start;
 359                         total_added += size;
 360                         ret = btrfs_add_free_space(block_group, start,
 361                                                    size);
 362                         BUG_ON(ret); /* -ENOMEM or logic error */
 363                         start = extent_end + 1;
 364                 } else {
 365                         break;
 366                 }
 367         }
 368
 369         if (start < end) {
 370                 size = end - start;
 371                 total_added += size;
 372                 ret = btrfs_add_free_space(block_group, start, size);
 373                 BUG_ON(ret); /* -ENOMEM or logic error */
 374         }
 375
 376         return total_added;
 377 }
 378
 379 static noinline void caching_thread(struct btrfs_work *work)
 380 {
 381         struct btrfs_block_group_cache *block_group;
 382         struct btrfs_fs_info *fs_info;
 383         struct btrfs_caching_control *caching_ctl;
 384         struct btrfs_root *extent_root;
 385         struct btrfs_path *path;
 386         struct extent_buffer *leaf;
 387         struct btrfs_key key;
 388         u64 total_found = 0;
 389         u64 last = 0;
 390         u32 nritems;
 391         int ret = -ENOMEM;
 392
 393         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 394         block_group = caching_ctl->block_group;
 395         fs_info = block_group->fs_info;
 396         extent_root = fs_info->extent_root;
 397
 398         path = btrfs_alloc_path();
 399         if (!path)
 400                 goto out;
 401
 402         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 403
 404         /*
 405          * We don't want to deadlock with somebody trying to allocate a new
 406          * extent for the extent root while also trying to search the extent
 407          * root to add free space.  So we skip locking and search the commit
 408          * root, since its read-only
 409          */
 410         path->skip_locking = 1;
 411         path->search_commit_root = 1;
 412         path->reada = 1;
 413
 414         key.objectid = last;
 415         key.offset = 0;
 416         key.type = BTRFS_EXTENT_ITEM_KEY;
 417 again:
 418         mutex_lock(&caching_ctl->mutex);
 419         /* need to make sure the commit_root doesn't disappear */
 420         down_read(&fs_info->commit_root_sem);
 421
 422 next:
 423         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 424         if (ret < 0)
 425                 goto err;
 426
 427         leaf = path->nodes[0];
 428         nritems = btrfs_header_nritems(leaf);
 429
 430         while (1) {
 431                 if (btrfs_fs_closing(fs_info) > 1) {
 432                         last = (u64)-1;
 433                         break;
 434                 }
 435
 436                 if (path->slots[0] < nritems) {
 437                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 438                 } else {
 439                         ret = find_next_key(path, 0, &key);
 440                         if (ret)
 441                                 break;
 442
 443                         if (need_resched() ||
 444                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 445                                 caching_ctl->progress = last;
 446                                 btrfs_release_path(path);
 447                                 up_read(&fs_info->commit_root_sem);
 448                                 mutex_unlock(&caching_ctl->mutex);
 449                                 cond_resched();
 450                                 goto again;
 451                         }
 452
 453                         ret = btrfs_next_leaf(extent_root, path);
 454                         if (ret < 0)
 455                                 goto err;
 456                         if (ret)
 457                                 break;
 458                         leaf = path->nodes[0];
 459                         nritems = btrfs_header_nritems(leaf);
 460                         continue;
 461                 }
 462
 463                 if (key.objectid < last) {
 464                         key.objectid = last;
 465                         key.offset = 0;
 466                         key.type = BTRFS_EXTENT_ITEM_KEY;
 467
 468                         caching_ctl->progress = last;
 469                         btrfs_release_path(path);
 470                         goto next;
 471                 }
 472
 473                 if (key.objectid < block_group->key.objectid) {
 474                         path->slots[0]++;
 475                         continue;
 476                 }
 477
 478                 if (key.objectid >= block_group->key.objectid +
 479                     block_group->key.offset)
 480                         break;
 481
 482                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 483                     key.type == BTRFS_METADATA_ITEM_KEY) {
 484                         total_found += add_new_free_space(block_group,
 485                                                           fs_info, last,
 486                                                           key.objectid);
 487                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 488                                 last = key.objectid +
 489                                         fs_info->tree_root->nodesize;
 490                         else
 491                                 last = key.objectid + key.offset;
 492
 493                         if (total_found > (1024 * 1024 * 2)) {
 494                                 total_found = 0;
 495                                 wake_up(&caching_ctl->wait);
 496                         }
 497                 }
 498                 path->slots[0]++;
 499         }
 500         ret = 0;
 501
 502         total_found += add_new_free_space(block_group, fs_info, last,
 503                                           block_group->key.objectid +
 504                                           block_group->key.offset);
 505         caching_ctl->progress = (u64)-1;
 506
 507         spin_lock(&block_group->lock);
 508         block_group->caching_ctl = NULL;
 509         block_group->cached = BTRFS_CACHE_FINISHED;
 510         spin_unlock(&block_group->lock);
 511
 512 err:
 513         btrfs_free_path(path);
 514         up_read(&fs_info->commit_root_sem);
 515
 516         free_excluded_extents(extent_root, block_group);
 517
 518         mutex_unlock(&caching_ctl->mutex);
 519 out:
 520         if (ret) {
 521                 spin_lock(&block_group->lock);
 522                 block_group->caching_ctl = NULL;
 523                 block_group->cached = BTRFS_CACHE_ERROR;
 524                 spin_unlock(&block_group->lock);
 525         }
 526         wake_up(&caching_ctl->wait);
 527
 528         put_caching_control(caching_ctl);
 529         btrfs_put_block_group(block_group);
 530 }
 531
 532 static int cache_block_group(struct btrfs_block_group_cache *cache,
 533                              int load_cache_only)
 534 {
 535         DEFINE_WAIT(wait);
 536         struct btrfs_fs_info *fs_info = cache->fs_info;
 537         struct btrfs_caching_control *caching_ctl;
 538         int ret = 0;
 539
 540         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 541         if (!caching_ctl)
 542                 return -ENOMEM;
 543
 544         INIT_LIST_HEAD(&caching_ctl->list);
 545         mutex_init(&caching_ctl->mutex);
 546         init_waitqueue_head(&caching_ctl->wait);
 547         caching_ctl->block_group = cache;
 548         caching_ctl->progress = cache->key.objectid;
 549         atomic_set(&caching_ctl->count, 1);
 550         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 551                         caching_thread, NULL, NULL);
 552
 553         spin_lock(&cache->lock);
 554         /*
 555          * This should be a rare occasion, but this could happen I think in the
 556          * case where one thread starts to load the space cache info, and then
 557          * some other thread starts a transaction commit which tries to do an
 558          * allocation while the other thread is still loading the space cache
 559          * info.  The previous loop should have kept us from choosing this block
 560          * group, but if we've moved to the state where we will wait on caching
 561          * block groups we need to first check if we're doing a fast load here,
 562          * so we can wait for it to finish, otherwise we could end up allocating
 563          * from a block group who's cache gets evicted for one reason or
 564          * another.
 565          */
 566         while (cache->cached == BTRFS_CACHE_FAST) {
 567                 struct btrfs_caching_control *ctl;
 568
 569                 ctl = cache->caching_ctl;
 570                 atomic_inc(&ctl->count);
 571                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 572                 spin_unlock(&cache->lock);
 573
 574                 schedule();
 575
 576                 finish_wait(&ctl->wait, &wait);
 577                 put_caching_control(ctl);
 578                 spin_lock(&cache->lock);
 579         }
 580
 581         if (cache->cached != BTRFS_CACHE_NO) {
 582                 spin_unlock(&cache->lock);
 583                 kfree(caching_ctl);
 584                 return 0;
 585         }
 586         WARN_ON(cache->caching_ctl);
 587         cache->caching_ctl = caching_ctl;
 588         cache->cached = BTRFS_CACHE_FAST;
 589         spin_unlock(&cache->lock);
 590
 591         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 592                 mutex_lock(&caching_ctl->mutex);
 593                 ret = load_free_space_cache(fs_info, cache);
 594
 595                 spin_lock(&cache->lock);
 596                 if (ret == 1) {
 597                         cache->caching_ctl = NULL;
 598                         cache->cached = BTRFS_CACHE_FINISHED;
 599                         cache->last_byte_to_unpin = (u64)-1;
 600                         caching_ctl->progress = (u64)-1;
 601                 } else {
 602                         if (load_cache_only) {
 603                                 cache->caching_ctl = NULL;
 604                                 cache->cached = BTRFS_CACHE_NO;
 605                         } else {
 606                                 cache->cached = BTRFS_CACHE_STARTED;
 607                                 cache->has_caching_ctl = 1;
 608                         }
 609                 }
 610                 spin_unlock(&cache->lock);
 611                 mutex_unlock(&caching_ctl->mutex);
 612
 613                 wake_up(&caching_ctl->wait);
 614                 if (ret == 1) {
 615                         put_caching_control(caching_ctl);
 616                         free_excluded_extents(fs_info->extent_root, cache);
 617                         return 0;
 618                 }
 619         } else {
 620                 /*
 621                  * We are not going to do the fast caching, set cached to the
 622                  * appropriate value and wakeup any waiters.
 623                  */
 624                 spin_lock(&cache->lock);
 625                 if (load_cache_only) {
 626                         cache->caching_ctl = NULL;
 627                         cache->cached = BTRFS_CACHE_NO;
 628                 } else {
 629                         cache->cached = BTRFS_CACHE_STARTED;
 630                         cache->has_caching_ctl = 1;
 631                 }
 632                 spin_unlock(&cache->lock);
 633                 wake_up(&caching_ctl->wait);
 634         }
 635
 636         if (load_cache_only) {
 637                 put_caching_control(caching_ctl);
 638                 return 0;
 639         }
 640
 641         down_write(&fs_info->commit_root_sem);
 642         atomic_inc(&caching_ctl->count);
 643         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 644         up_write(&fs_info->commit_root_sem);
 645
 646         btrfs_get_block_group(cache);
 647
 648         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 649
 650         return ret;
 651 }
 652
 653 /*
 654  * return the block group that starts at or after bytenr
 655  */
 656 static struct btrfs_block_group_cache *
 657 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 658 {
 659         struct btrfs_block_group_cache *cache;
 660
 661         cache = block_group_cache_tree_search(info, bytenr, 0);
 662
 663         return cache;
 664 }
 665
 666 /*
 667  * return the block group that contains the given bytenr
 668  */
 669 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 670                                                  struct btrfs_fs_info *info,
 671                                                  u64 bytenr)
 672 {
 673         struct btrfs_block_group_cache *cache;
 674
 675         cache = block_group_cache_tree_search(info, bytenr, 1);
 676
 677         return cache;
 678 }
 679
 680 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 681                                                   u64 flags)
 682 {
 683         struct list_head *head = &info->space_info;
 684         struct btrfs_space_info *found;
 685
 686         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 687
 688         rcu_read_lock();
 689         list_for_each_entry_rcu(found, head, list) {
 690                 if (found->flags & flags) {
 691                         rcu_read_unlock();
 692                         return found;
 693                 }
 694         }
 695         rcu_read_unlock();
 696         return NULL;
 697 }
 698
 699 /*
 700  * after adding space to the filesystem, we need to clear the full flags
 701  * on all the space infos.
 702  */
 703 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 704 {
 705         struct list_head *head = &info->space_info;
 706         struct btrfs_space_info *found;
 707
 708         rcu_read_lock();
 709         list_for_each_entry_rcu(found, head, list)
 710                 found->full = 0;
 711         rcu_read_unlock();
 712 }
 713
 714 /* simple helper to search for an existing data extent at a given offset */
 715 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
 716 {
 717         int ret;
 718         struct btrfs_key key;
 719         struct btrfs_path *path;
 720
 721         path = btrfs_alloc_path();
 722         if (!path)
 723                 return -ENOMEM;
 724
 725         key.objectid = start;
 726         key.offset = len;
 727         key.type = BTRFS_EXTENT_ITEM_KEY;
 728         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 729                                 0, 0);
 730         btrfs_free_path(path);
 731         return ret;
 732 }
 733
 734 /*
 735  * helper function to lookup reference count and flags of a tree block.
 736  *
 737  * the head node for delayed ref is used to store the sum of all the
 738  * reference count modifications queued up in the rbtree. the head
 739  * node may also store the extent flags to set. This way you can check
 740  * to see what the reference count and extent flags would be if all of
 741  * the delayed refs are not processed.
 742  */
 743 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 744                              struct btrfs_root *root, u64 bytenr,
 745                              u64 offset, int metadata, u64 *refs, u64 *flags)
 746 {
 747         struct btrfs_delayed_ref_head *head;
 748         struct btrfs_delayed_ref_root *delayed_refs;
 749         struct btrfs_path *path;
 750         struct btrfs_extent_item *ei;
 751         struct extent_buffer *leaf;
 752         struct btrfs_key key;
 753         u32 item_size;
 754         u64 num_refs;
 755         u64 extent_flags;
 756         int ret;
 757
 758         /*
 759          * If we don't have skinny metadata, don't bother doing anything
 760          * different
 761          */
 762         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 763                 offset = root->nodesize;
 764                 metadata = 0;
 765         }
 766
 767         path = btrfs_alloc_path();
 768         if (!path)
 769                 return -ENOMEM;
 770
 771         if (!trans) {
 772                 path->skip_locking = 1;
 773                 path->search_commit_root = 1;
 774         }
 775
 776 search_again:
 777         key.objectid = bytenr;
 778         key.offset = offset;
 779         if (metadata)
 780                 key.type = BTRFS_METADATA_ITEM_KEY;
 781         else
 782                 key.type = BTRFS_EXTENT_ITEM_KEY;
 783
 784         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 785                                 &key, path, 0, 0);
 786         if (ret < 0)
 787                 goto out_free;
 788
 789         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 790                 if (path->slots[0]) {
 791                         path->slots[0]--;
 792                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 793                                               path->slots[0]);
 794                         if (key.objectid == bytenr &&
 795                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 796                             key.offset == root->nodesize)
 797                                 ret = 0;
 798                 }
 799         }
 800
 801         if (ret == 0) {
 802                 leaf = path->nodes[0];
 803                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 804                 if (item_size >= sizeof(*ei)) {
 805                         ei = btrfs_item_ptr(leaf, path->slots[0],
 806                                             struct btrfs_extent_item);
 807                         num_refs = btrfs_extent_refs(leaf, ei);
 808                         extent_flags = btrfs_extent_flags(leaf, ei);
 809                 } else {
 810 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 811                         struct btrfs_extent_item_v0 *ei0;
 812                         BUG_ON(item_size != sizeof(*ei0));
 813                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 814                                              struct btrfs_extent_item_v0);
 815                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 816                         /* FIXME: this isn't correct for data */
 817                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 818 #else
 819                         BUG();
 820 #endif
 821                 }
 822                 BUG_ON(num_refs == 0);
 823         } else {
 824                 num_refs = 0;
 825                 extent_flags = 0;
 826                 ret = 0;
 827         }
 828
 829         if (!trans)
 830                 goto out;
 831
 832         delayed_refs = &trans->transaction->delayed_refs;
 833         spin_lock(&delayed_refs->lock);
 834         head = btrfs_find_delayed_ref_head(trans, bytenr);
 835         if (head) {
 836                 if (!mutex_trylock(&head->mutex)) {
 837                         atomic_inc(&head->node.refs);
 838                         spin_unlock(&delayed_refs->lock);
 839
 840                         btrfs_release_path(path);
 841
 842                         /*
 843                          * Mutex was contended, block until it's released and try
 844                          * again
 845                          */
 846                         mutex_lock(&head->mutex);
 847                         mutex_unlock(&head->mutex);
 848                         btrfs_put_delayed_ref(&head->node);
 849                         goto search_again;
 850                 }
 851                 spin_lock(&head->lock);
 852                 if (head->extent_op && head->extent_op->update_flags)
 853                         extent_flags |= head->extent_op->flags_to_set;
 854                 else
 855                         BUG_ON(num_refs == 0);
 856
 857                 num_refs += head->node.ref_mod;
 858                 spin_unlock(&head->lock);
 859                 mutex_unlock(&head->mutex);
 860         }
 861         spin_unlock(&delayed_refs->lock);
 862 out:
 863         WARN_ON(num_refs == 0);
 864         if (refs)
 865                 *refs = num_refs;
 866         if (flags)
 867                 *flags = extent_flags;
 868 out_free:
 869         btrfs_free_path(path);
 870         return ret;
 871 }
 872
 873 /*
 874  * Back reference rules.  Back refs have three main goals:
 875  *
 876  * 1) differentiate between all holders of references to an extent so that
 877  *    when a reference is dropped we can make sure it was a valid reference
 878  *    before freeing the extent.
 879  *
 880  * 2) Provide enough information to quickly find the holders of an extent
 881  *    if we notice a given block is corrupted or bad.
 882  *
 883  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 884  *    maintenance.  This is actually the same as #2, but with a slightly
 885  *    different use case.
 886  *
 887  * There are two kinds of back refs. The implicit back refs is optimized
 888  * for pointers in non-shared tree blocks. For a given pointer in a block,
 889  * back refs of this kind provide information about the block's owner tree
 890  * and the pointer's key. These information allow us to find the block by
 891  * b-tree searching. The full back refs is for pointers in tree blocks not
 892  * referenced by their owner trees. The location of tree block is recorded
 893  * in the back refs. Actually the full back refs is generic, and can be
 894  * used in all cases the implicit back refs is used. The major shortcoming
 895  * of the full back refs is its overhead. Every time a tree block gets
 896  * COWed, we have to update back refs entry for all pointers in it.
 897  *
 898  * For a newly allocated tree block, we use implicit back refs for
 899  * pointers in it. This means most tree related operations only involve
 900  * implicit back refs. For a tree block created in old transaction, the
 901  * only way to drop a reference to it is COW it. So we can detect the
 902  * event that tree block loses its owner tree's reference and do the
 903  * back refs conversion.
 904  *
 905  * When a tree block is COW'd through a tree, there are four cases:
 906  *
 907  * The reference count of the block is one and the tree is the block's
 908  * owner tree. Nothing to do in this case.
 909  *
 910  * The reference count of the block is one and the tree is not the
 911  * block's owner tree. In this case, full back refs is used for pointers
 912  * in the block. Remove these full back refs, add implicit back refs for
 913  * every pointers in the new block.
 914  *
 915  * The reference count of the block is greater than one and the tree is
 916  * the block's owner tree. In this case, implicit back refs is used for
 917  * pointers in the block. Add full back refs for every pointers in the
 918  * block, increase lower level extents' reference counts. The original
 919  * implicit back refs are entailed to the new block.
 920  *
 921  * The reference count of the block is greater than one and the tree is
 922  * not the block's owner tree. Add implicit back refs for every pointer in
 923  * the new block, increase lower level extents' reference count.
 924  *
 925  * Back Reference Key composing:
 926  *
 927  * The key objectid corresponds to the first byte in the extent,
 928  * The key type is used to differentiate between types of back refs.
 929  * There are different meanings of the key offset for different types
 930  * of back refs.
 931  *
 932  * File extents can be referenced by:
 933  *
 934  * - multiple snapshots, subvolumes, or different generations in one subvol
 935  * - different files inside a single subvolume
 936  * - different offsets inside a file (bookend extents in file.c)
 937  *
 938  * The extent ref structure for the implicit back refs has fields for:
 939  *
 940  * - Objectid of the subvolume root
 941  * - objectid of the file holding the reference
 942  * - original offset in the file
 943  * - how many bookend extents
 944  *
 945  * The key offset for the implicit back refs is hash of the first
 946  * three fields.
 947  *
 948  * The extent ref structure for the full back refs has field for:
 949  *
 950  * - number of pointers in the tree leaf
 951  *
 952  * The key offset for the implicit back refs is the first byte of
 953  * the tree leaf
 954  *
 955  * When a file extent is allocated, The implicit back refs is used.
 956  * the fields are filled in:
 957  *
 958  *     (root_key.objectid, inode objectid, offset in file, 1)
 959  *
 960  * When a file extent is removed file truncation, we find the
 961  * corresponding implicit back refs and check the following fields:
 962  *
 963  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 964  *
 965  * Btree extents can be referenced by:
 966  *
 967  * - Different subvolumes
 968  *
 969  * Both the implicit back refs and the full back refs for tree blocks
 970  * only consist of key. The key offset for the implicit back refs is
 971  * objectid of block's owner tree. The key offset for the full back refs
 972  * is the first byte of parent block.
 973  *
 974  * When implicit back refs is used, information about the lowest key and
 975  * level of the tree block are required. These information are stored in
 976  * tree block info structure.
 977  */
 978
 979 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 980 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 981                                   struct btrfs_root *root,
 982                                   struct btrfs_path *path,
 983                                   u64 owner, u32 extra_size)
 984 {
 985         struct btrfs_extent_item *item;
 986         struct btrfs_extent_item_v0 *ei0;
 987         struct btrfs_extent_ref_v0 *ref0;
 988         struct btrfs_tree_block_info *bi;
 989         struct extent_buffer *leaf;
 990         struct btrfs_key key;
 991         struct btrfs_key found_key;
 992         u32 new_size = sizeof(*item);
 993         u64 refs;
 994         int ret;
 995
 996         leaf = path->nodes[0];
 997         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 998
 999         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1000         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1001                              struct btrfs_extent_item_v0);
1002         refs = btrfs_extent_refs_v0(leaf, ei0);
1003
1004         if (owner == (u64)-1) {
1005                 while (1) {
1006                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1007                                 ret = btrfs_next_leaf(root, path);
1008                                 if (ret < 0)
1009                                         return ret;
1010                                 BUG_ON(ret > 0); /* Corruption */
1011                                 leaf = path->nodes[0];
1012                         }
1013                         btrfs_item_key_to_cpu(leaf, &found_key,
1014                                               path->slots[0]);
1015                         BUG_ON(key.objectid != found_key.objectid);
1016                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1017                                 path->slots[0]++;
1018                                 continue;
1019                         }
1020                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1021                                               struct btrfs_extent_ref_v0);
1022                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1023                         break;
1024                 }
1025         }
1026         btrfs_release_path(path);
1027
1028         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1029                 new_size += sizeof(*bi);
1030
1031         new_size -= sizeof(*ei0);
1032         ret = btrfs_search_slot(trans, root, &key, path,
1033                                 new_size + extra_size, 1);
1034         if (ret < 0)
1035                 return ret;
1036         BUG_ON(ret); /* Corruption */
1037
1038         btrfs_extend_item(root, path, new_size);
1039
1040         leaf = path->nodes[0];
1041         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1042         btrfs_set_extent_refs(leaf, item, refs);
1043         /* FIXME: get real generation */
1044         btrfs_set_extent_generation(leaf, item, 0);
1045         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1046                 btrfs_set_extent_flags(leaf, item,
1047                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1048                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1049                 bi = (struct btrfs_tree_block_info *)(item + 1);
1050                 /* FIXME: get first key of the block */
1051                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1052                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1053         } else {
1054                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1055         }
1056         btrfs_mark_buffer_dirty(leaf);
1057         return 0;
1058 }
1059 #endif
1060
1061 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1062 {
1063         u32 high_crc = ~(u32)0;
1064         u32 low_crc = ~(u32)0;
1065         __le64 lenum;
1066
1067         lenum = cpu_to_le64(root_objectid);
1068         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1069         lenum = cpu_to_le64(owner);
1070         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1071         lenum = cpu_to_le64(offset);
1072         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1073
1074         return ((u64)high_crc << 31) ^ (u64)low_crc;
1075 }
1076
1077 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1078                                      struct btrfs_extent_data_ref *ref)
1079 {
1080         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1081                                     btrfs_extent_data_ref_objectid(leaf, ref),
1082                                     btrfs_extent_data_ref_offset(leaf, ref));
1083 }
1084
1085 static int match_extent_data_ref(struct extent_buffer *leaf,
1086                                  struct btrfs_extent_data_ref *ref,
1087                                  u64 root_objectid, u64 owner, u64 offset)
1088 {
1089         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1090             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1091             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1092                 return 0;
1093         return 1;
1094 }
1095
1096 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1097                                            struct btrfs_root *root,
1098                                            struct btrfs_path *path,
1099                                            u64 bytenr, u64 parent,
1100                                            u64 root_objectid,
1101                                            u64 owner, u64 offset)
1102 {
1103         struct btrfs_key key;
1104         struct btrfs_extent_data_ref *ref;
1105         struct extent_buffer *leaf;
1106         u32 nritems;
1107         int ret;
1108         int recow;
1109         int err = -ENOENT;
1110
1111         key.objectid = bytenr;
1112         if (parent) {
1113                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1114                 key.offset = parent;
1115         } else {
1116                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1117                 key.offset = hash_extent_data_ref(root_objectid,
1118                                                   owner, offset);
1119         }
1120 again:
1121         recow = 0;
1122         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1123         if (ret < 0) {
1124                 err = ret;
1125                 goto fail;
1126         }
1127
1128         if (parent) {
1129                 if (!ret)
1130                         return 0;
1131 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1132                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1133                 btrfs_release_path(path);
1134                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1135                 if (ret < 0) {
1136                         err = ret;
1137                         goto fail;
1138                 }
1139                 if (!ret)
1140                         return 0;
1141 #endif
1142                 goto fail;
1143         }
1144
1145         leaf = path->nodes[0];
1146         nritems = btrfs_header_nritems(leaf);
1147         while (1) {
1148                 if (path->slots[0] >= nritems) {
1149                         ret = btrfs_next_leaf(root, path);
1150                         if (ret < 0)
1151                                 err = ret;
1152                         if (ret)
1153                                 goto fail;
1154
1155                         leaf = path->nodes[0];
1156                         nritems = btrfs_header_nritems(leaf);
1157                         recow = 1;
1158                 }
1159
1160                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1161                 if (key.objectid != bytenr ||
1162                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1163                         goto fail;
1164
1165                 ref = btrfs_item_ptr(leaf, path->slots[0],
1166                                      struct btrfs_extent_data_ref);
1167
1168                 if (match_extent_data_ref(leaf, ref, root_objectid,
1169                                           owner, offset)) {
1170                         if (recow) {
1171                                 btrfs_release_path(path);
1172                                 goto again;
1173                         }
1174                         err = 0;
1175                         break;
1176                 }
1177                 path->slots[0]++;
1178         }
1179 fail:
1180         return err;
1181 }
1182
1183 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1184                                            struct btrfs_root *root,
1185                                            struct btrfs_path *path,
1186                                            u64 bytenr, u64 parent,
1187                                            u64 root_objectid, u64 owner,
1188                                            u64 offset, int refs_to_add)
1189 {
1190         struct btrfs_key key;
1191         struct extent_buffer *leaf;
1192         u32 size;
1193         u32 num_refs;
1194         int ret;
1195
1196         key.objectid = bytenr;
1197         if (parent) {
1198                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1199                 key.offset = parent;
1200                 size = sizeof(struct btrfs_shared_data_ref);
1201         } else {
1202                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1203                 key.offset = hash_extent_data_ref(root_objectid,
1204                                                   owner, offset);
1205                 size = sizeof(struct btrfs_extent_data_ref);
1206         }
1207
1208         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1209         if (ret && ret != -EEXIST)
1210                 goto fail;
1211
1212         leaf = path->nodes[0];
1213         if (parent) {
1214                 struct btrfs_shared_data_ref *ref;
1215                 ref = btrfs_item_ptr(leaf, path->slots[0],
1216                                      struct btrfs_shared_data_ref);
1217                 if (ret == 0) {
1218                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1219                 } else {
1220                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1221                         num_refs += refs_to_add;
1222                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1223                 }
1224         } else {
1225                 struct btrfs_extent_data_ref *ref;
1226                 while (ret == -EEXIST) {
1227                         ref = btrfs_item_ptr(leaf, path->slots[0],
1228                                              struct btrfs_extent_data_ref);
1229                         if (match_extent_data_ref(leaf, ref, root_objectid,
1230                                                   owner, offset))
1231                                 break;
1232                         btrfs_release_path(path);
1233                         key.offset++;
1234                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1235                                                       size);
1236                         if (ret && ret != -EEXIST)
1237                                 goto fail;
1238
1239                         leaf = path->nodes[0];
1240                 }
1241                 ref = btrfs_item_ptr(leaf, path->slots[0],
1242                                      struct btrfs_extent_data_ref);
1243                 if (ret == 0) {
1244                         btrfs_set_extent_data_ref_root(leaf, ref,
1245                                                        root_objectid);
1246                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1247                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1248                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1249                 } else {
1250                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1251                         num_refs += refs_to_add;
1252                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1253                 }
1254         }
1255         btrfs_mark_buffer_dirty(leaf);
1256         ret = 0;
1257 fail:
1258         btrfs_release_path(path);
1259         return ret;
1260 }
1261
1262 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1263                                            struct btrfs_root *root,
1264                                            struct btrfs_path *path,
1265                                            int refs_to_drop, int *last_ref)
1266 {
1267         struct btrfs_key key;
1268         struct btrfs_extent_data_ref *ref1 = NULL;
1269         struct btrfs_shared_data_ref *ref2 = NULL;
1270         struct extent_buffer *leaf;
1271         u32 num_refs = 0;
1272         int ret = 0;
1273
1274         leaf = path->nodes[0];
1275         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1276
1277         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1278                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1279                                       struct btrfs_extent_data_ref);
1280                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1281         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1282                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1283                                       struct btrfs_shared_data_ref);
1284                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1285 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1286         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1287                 struct btrfs_extent_ref_v0 *ref0;
1288                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1289                                       struct btrfs_extent_ref_v0);
1290                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1291 #endif
1292         } else {
1293                 BUG();
1294         }
1295
1296         BUG_ON(num_refs < refs_to_drop);
1297         num_refs -= refs_to_drop;
1298
1299         if (num_refs == 0) {
1300                 ret = btrfs_del_item(trans, root, path);
1301                 *last_ref = 1;
1302         } else {
1303                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1304                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1305                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1306                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1307 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1308                 else {
1309                         struct btrfs_extent_ref_v0 *ref0;
1310                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1311                                         struct btrfs_extent_ref_v0);
1312                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1313                 }
1314 #endif
1315                 btrfs_mark_buffer_dirty(leaf);
1316         }
1317         return ret;
1318 }
1319
1320 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1321                                           struct btrfs_path *path,
1322                                           struct btrfs_extent_inline_ref *iref)
1323 {
1324         struct btrfs_key key;
1325         struct extent_buffer *leaf;
1326         struct btrfs_extent_data_ref *ref1;
1327         struct btrfs_shared_data_ref *ref2;
1328         u32 num_refs = 0;
1329
1330         leaf = path->nodes[0];
1331         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1332         if (iref) {
1333                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1334                     BTRFS_EXTENT_DATA_REF_KEY) {
1335                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1336                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1337                 } else {
1338                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1339                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1340                 }
1341         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1342                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1343                                       struct btrfs_extent_data_ref);
1344                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1345         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1346                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1347                                       struct btrfs_shared_data_ref);
1348                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1349 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1350         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1351                 struct btrfs_extent_ref_v0 *ref0;
1352                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1353                                       struct btrfs_extent_ref_v0);
1354                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1355 #endif
1356         } else {
1357                 WARN_ON(1);
1358         }
1359         return num_refs;
1360 }
1361
1362 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1363                                           struct btrfs_root *root,
1364                                           struct btrfs_path *path,
1365                                           u64 bytenr, u64 parent,
1366                                           u64 root_objectid)
1367 {
1368         struct btrfs_key key;
1369         int ret;
1370
1371         key.objectid = bytenr;
1372         if (parent) {
1373                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1374                 key.offset = parent;
1375         } else {
1376                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1377                 key.offset = root_objectid;
1378         }
1379
1380         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1381         if (ret > 0)
1382                 ret = -ENOENT;
1383 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1384         if (ret == -ENOENT && parent) {
1385                 btrfs_release_path(path);
1386                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1387                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1388                 if (ret > 0)
1389                         ret = -ENOENT;
1390         }
1391 #endif
1392         return ret;
1393 }
1394
1395 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1396                                           struct btrfs_root *root,
1397                                           struct btrfs_path *path,
1398                                           u64 bytenr, u64 parent,
1399                                           u64 root_objectid)
1400 {
1401         struct btrfs_key key;
1402         int ret;
1403
1404         key.objectid = bytenr;
1405         if (parent) {
1406                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1407                 key.offset = parent;
1408         } else {
1409                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1410                 key.offset = root_objectid;
1411         }
1412
1413         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1414         btrfs_release_path(path);
1415         return ret;
1416 }
1417
1418 static inline int extent_ref_type(u64 parent, u64 owner)
1419 {
1420         int type;
1421         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1422                 if (parent > 0)
1423                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1424                 else
1425                         type = BTRFS_TREE_BLOCK_REF_KEY;
1426         } else {
1427                 if (parent > 0)
1428                         type = BTRFS_SHARED_DATA_REF_KEY;
1429                 else
1430                         type = BTRFS_EXTENT_DATA_REF_KEY;
1431         }
1432         return type;
1433 }
1434
1435 static int find_next_key(struct btrfs_path *path, int level,
1436                          struct btrfs_key *key)
1437
1438 {
1439         for (; level < BTRFS_MAX_LEVEL; level++) {
1440                 if (!path->nodes[level])
1441                         break;
1442                 if (path->slots[level] + 1 >=
1443                     btrfs_header_nritems(path->nodes[level]))
1444                         continue;
1445                 if (level == 0)
1446                         btrfs_item_key_to_cpu(path->nodes[level], key,
1447                                               path->slots[level] + 1);
1448                 else
1449                         btrfs_node_key_to_cpu(path->nodes[level], key,
1450                                               path->slots[level] + 1);
1451                 return 0;
1452         }
1453         return 1;
1454 }
1455
1456 /*
1457  * look for inline back ref. if back ref is found, *ref_ret is set
1458  * to the address of inline back ref, and 0 is returned.
1459  *
1460  * if back ref isn't found, *ref_ret is set to the address where it
1461  * should be inserted, and -ENOENT is returned.
1462  *
1463  * if insert is true and there are too many inline back refs, the path
1464  * points to the extent item, and -EAGAIN is returned.
1465  *
1466  * NOTE: inline back refs are ordered in the same way that back ref
1467  *       items in the tree are ordered.
1468  */
1469 static noinline_for_stack
1470 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1471                                  struct btrfs_root *root,
1472                                  struct btrfs_path *path,
1473                                  struct btrfs_extent_inline_ref **ref_ret,
1474                                  u64 bytenr, u64 num_bytes,
1475                                  u64 parent, u64 root_objectid,
1476                                  u64 owner, u64 offset, int insert)
1477 {
1478         struct btrfs_key key;
1479         struct extent_buffer *leaf;
1480         struct btrfs_extent_item *ei;
1481         struct btrfs_extent_inline_ref *iref;
1482         u64 flags;
1483         u64 item_size;
1484         unsigned long ptr;
1485         unsigned long end;
1486         int extra_size;
1487         int type;
1488         int want;
1489         int ret;
1490         int err = 0;
1491         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1492                                                  SKINNY_METADATA);
1493
1494         key.objectid = bytenr;
1495         key.type = BTRFS_EXTENT_ITEM_KEY;
1496         key.offset = num_bytes;
1497
1498         want = extent_ref_type(parent, owner);
1499         if (insert) {
1500                 extra_size = btrfs_extent_inline_ref_size(want);
1501                 path->keep_locks = 1;
1502         } else
1503                 extra_size = -1;
1504
1505         /*
1506          * Owner is our parent level, so we can just add one to get the level
1507          * for the block we are interested in.
1508          */
1509         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1510                 key.type = BTRFS_METADATA_ITEM_KEY;
1511                 key.offset = owner;
1512         }
1513
1514 again:
1515         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1516         if (ret < 0) {
1517                 err = ret;
1518                 goto out;
1519         }
1520
1521         /*
1522          * We may be a newly converted file system which still has the old fat
1523          * extent entries for metadata, so try and see if we have one of those.
1524          */
1525         if (ret > 0 && skinny_metadata) {
1526                 skinny_metadata = false;
1527                 if (path->slots[0]) {
1528                         path->slots[0]--;
1529                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1530                                               path->slots[0]);
1531                         if (key.objectid == bytenr &&
1532                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1533                             key.offset == num_bytes)
1534                                 ret = 0;
1535                 }
1536                 if (ret) {
1537                         key.objectid = bytenr;
1538                         key.type = BTRFS_EXTENT_ITEM_KEY;
1539                         key.offset = num_bytes;
1540                         btrfs_release_path(path);
1541                         goto again;
1542                 }
1543         }
1544
1545         if (ret && !insert) {
1546                 err = -ENOENT;
1547                 goto out;
1548         } else if (WARN_ON(ret)) {
1549                 err = -EIO;
1550                 goto out;
1551         }
1552
1553         leaf = path->nodes[0];
1554         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1555 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1556         if (item_size < sizeof(*ei)) {
1557                 if (!insert) {
1558                         err = -ENOENT;
1559                         goto out;
1560                 }
1561                 ret = convert_extent_item_v0(trans, root, path, owner,
1562                                              extra_size);
1563                 if (ret < 0) {
1564                         err = ret;
1565                         goto out;
1566                 }
1567                 leaf = path->nodes[0];
1568                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1569         }
1570 #endif
1571         BUG_ON(item_size < sizeof(*ei));
1572
1573         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1574         flags = btrfs_extent_flags(leaf, ei);
1575
1576         ptr = (unsigned long)(ei + 1);
1577         end = (unsigned long)ei + item_size;
1578
1579         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1580                 ptr += sizeof(struct btrfs_tree_block_info);
1581                 BUG_ON(ptr > end);
1582         }
1583
1584         err = -ENOENT;
1585         while (1) {
1586                 if (ptr >= end) {
1587                         WARN_ON(ptr > end);
1588                         break;
1589                 }
1590                 iref = (struct btrfs_extent_inline_ref *)ptr;
1591                 type = btrfs_extent_inline_ref_type(leaf, iref);
1592                 if (want < type)
1593                         break;
1594                 if (want > type) {
1595                         ptr += btrfs_extent_inline_ref_size(type);
1596                         continue;
1597                 }
1598
1599                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1600                         struct btrfs_extent_data_ref *dref;
1601                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1602                         if (match_extent_data_ref(leaf, dref, root_objectid,
1603                                                   owner, offset)) {
1604                                 err = 0;
1605                                 break;
1606                         }
1607                         if (hash_extent_data_ref_item(leaf, dref) <
1608                             hash_extent_data_ref(root_objectid, owner, offset))
1609                                 break;
1610                 } else {
1611                         u64 ref_offset;
1612                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1613                         if (parent > 0) {
1614                                 if (parent == ref_offset) {
1615                                         err = 0;
1616                                         break;
1617                                 }
1618                                 if (ref_offset < parent)
1619                                         break;
1620                         } else {
1621                                 if (root_objectid == ref_offset) {
1622                                         err = 0;
1623                                         break;
1624                                 }
1625                                 if (ref_offset < root_objectid)
1626                                         break;
1627                         }
1628                 }
1629                 ptr += btrfs_extent_inline_ref_size(type);
1630         }
1631         if (err == -ENOENT && insert) {
1632                 if (item_size + extra_size >=
1633                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1634                         err = -EAGAIN;
1635                         goto out;
1636                 }
1637                 /*
1638                  * To add new inline back ref, we have to make sure
1639                  * there is no corresponding back ref item.
1640                  * For simplicity, we just do not add new inline back
1641                  * ref if there is any kind of item for this block
1642                  */
1643                 if (find_next_key(path, 0, &key) == 0 &&
1644                     key.objectid == bytenr &&
1645                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1646                         err = -EAGAIN;
1647                         goto out;
1648                 }
1649         }
1650         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1651 out:
1652         if (insert) {
1653                 path->keep_locks = 0;
1654                 btrfs_unlock_up_safe(path, 1);
1655         }
1656         return err;
1657 }
1658
1659 /*
1660  * helper to add new inline back ref
1661  */
1662 static noinline_for_stack
1663 void setup_inline_extent_backref(struct btrfs_root *root,
1664                                  struct btrfs_path *path,
1665                                  struct btrfs_extent_inline_ref *iref,
1666                                  u64 parent, u64 root_objectid,
1667                                  u64 owner, u64 offset, int refs_to_add,
1668                                  struct btrfs_delayed_extent_op *extent_op)
1669 {
1670         struct extent_buffer *leaf;
1671         struct btrfs_extent_item *ei;
1672         unsigned long ptr;
1673         unsigned long end;
1674         unsigned long item_offset;
1675         u64 refs;
1676         int size;
1677         int type;
1678
1679         leaf = path->nodes[0];
1680         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1681         item_offset = (unsigned long)iref - (unsigned long)ei;
1682
1683         type = extent_ref_type(parent, owner);
1684         size = btrfs_extent_inline_ref_size(type);
1685
1686         btrfs_extend_item(root, path, size);
1687
1688         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1689         refs = btrfs_extent_refs(leaf, ei);
1690         refs += refs_to_add;
1691         btrfs_set_extent_refs(leaf, ei, refs);
1692         if (extent_op)
1693                 __run_delayed_extent_op(extent_op, leaf, ei);
1694
1695         ptr = (unsigned long)ei + item_offset;
1696         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1697         if (ptr < end - size)
1698                 memmove_extent_buffer(leaf, ptr + size, ptr,
1699                                       end - size - ptr);
1700
1701         iref = (struct btrfs_extent_inline_ref *)ptr;
1702         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1703         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1704                 struct btrfs_extent_data_ref *dref;
1705                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1706                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1707                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1708                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1709                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1710         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1711                 struct btrfs_shared_data_ref *sref;
1712                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1713                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1714                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1715         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1716                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1717         } else {
1718                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1719         }
1720         btrfs_mark_buffer_dirty(leaf);
1721 }
1722
1723 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1724                                  struct btrfs_root *root,
1725                                  struct btrfs_path *path,
1726                                  struct btrfs_extent_inline_ref **ref_ret,
1727                                  u64 bytenr, u64 num_bytes, u64 parent,
1728                                  u64 root_objectid, u64 owner, u64 offset)
1729 {
1730         int ret;
1731
1732         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1733                                            bytenr, num_bytes, parent,
1734                                            root_objectid, owner, offset, 0);
1735         if (ret != -ENOENT)
1736                 return ret;
1737
1738         btrfs_release_path(path);
1739         *ref_ret = NULL;
1740
1741         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1742                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1743                                             root_objectid);
1744         } else {
1745                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1746                                              root_objectid, owner, offset);
1747         }
1748         return ret;
1749 }
1750
1751 /*
1752  * helper to update/remove inline back ref
1753  */
1754 static noinline_for_stack
1755 void update_inline_extent_backref(struct btrfs_root *root,
1756                                   struct btrfs_path *path,
1757                                   struct btrfs_extent_inline_ref *iref,
1758                                   int refs_to_mod,
1759                                   struct btrfs_delayed_extent_op *extent_op,
1760                                   int *last_ref)
1761 {
1762         struct extent_buffer *leaf;
1763         struct btrfs_extent_item *ei;
1764         struct btrfs_extent_data_ref *dref = NULL;
1765         struct btrfs_shared_data_ref *sref = NULL;
1766         unsigned long ptr;
1767         unsigned long end;
1768         u32 item_size;
1769         int size;
1770         int type;
1771         u64 refs;
1772
1773         leaf = path->nodes[0];
1774         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1775         refs = btrfs_extent_refs(leaf, ei);
1776         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1777         refs += refs_to_mod;
1778         btrfs_set_extent_refs(leaf, ei, refs);
1779         if (extent_op)
1780                 __run_delayed_extent_op(extent_op, leaf, ei);
1781
1782         type = btrfs_extent_inline_ref_type(leaf, iref);
1783
1784         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1785                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1786                 refs = btrfs_extent_data_ref_count(leaf, dref);
1787         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1788                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1789                 refs = btrfs_shared_data_ref_count(leaf, sref);
1790         } else {
1791                 refs = 1;
1792                 BUG_ON(refs_to_mod != -1);
1793         }
1794
1795         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1796         refs += refs_to_mod;
1797
1798         if (refs > 0) {
1799                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1800                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1801                 else
1802                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1803         } else {
1804                 *last_ref = 1;
1805                 size =  btrfs_extent_inline_ref_size(type);
1806                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1807                 ptr = (unsigned long)iref;
1808                 end = (unsigned long)ei + item_size;
1809                 if (ptr + size < end)
1810                         memmove_extent_buffer(leaf, ptr, ptr + size,
1811                                               end - ptr - size);
1812                 item_size -= size;
1813                 btrfs_truncate_item(root, path, item_size, 1);
1814         }
1815         btrfs_mark_buffer_dirty(leaf);
1816 }
1817
1818 static noinline_for_stack
1819 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1820                                  struct btrfs_root *root,
1821                                  struct btrfs_path *path,
1822                                  u64 bytenr, u64 num_bytes, u64 parent,
1823                                  u64 root_objectid, u64 owner,
1824                                  u64 offset, int refs_to_add,
1825                                  struct btrfs_delayed_extent_op *extent_op)
1826 {
1827         struct btrfs_extent_inline_ref *iref;
1828         int ret;
1829
1830         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1831                                            bytenr, num_bytes, parent,
1832                                            root_objectid, owner, offset, 1);
1833         if (ret == 0) {
1834                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1835                 update_inline_extent_backref(root, path, iref,
1836                                              refs_to_add, extent_op, NULL);
1837         } else if (ret == -ENOENT) {
1838                 setup_inline_extent_backref(root, path, iref, parent,
1839                                             root_objectid, owner, offset,
1840                                             refs_to_add, extent_op);
1841                 ret = 0;
1842         }
1843         return ret;
1844 }
1845
1846 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1847                                  struct btrfs_root *root,
1848                                  struct btrfs_path *path,
1849                                  u64 bytenr, u64 parent, u64 root_objectid,
1850                                  u64 owner, u64 offset, int refs_to_add)
1851 {
1852         int ret;
1853         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1854                 BUG_ON(refs_to_add != 1);
1855                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1856                                             parent, root_objectid);
1857         } else {
1858                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1859                                              parent, root_objectid,
1860                                              owner, offset, refs_to_add);
1861         }
1862         return ret;
1863 }
1864
1865 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1866                                  struct btrfs_root *root,
1867                                  struct btrfs_path *path,
1868                                  struct btrfs_extent_inline_ref *iref,
1869                                  int refs_to_drop, int is_data, int *last_ref)
1870 {
1871         int ret = 0;
1872
1873         BUG_ON(!is_data && refs_to_drop != 1);
1874         if (iref) {
1875                 update_inline_extent_backref(root, path, iref,
1876                                              -refs_to_drop, NULL, last_ref);
1877         } else if (is_data) {
1878                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1879                                              last_ref);
1880         } else {
1881                 *last_ref = 1;
1882                 ret = btrfs_del_item(trans, root, path);
1883         }
1884         return ret;
1885 }
1886
1887 static int btrfs_issue_discard(struct block_device *bdev,
1888                                 u64 start, u64 len)
1889 {
1890         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1891 }
1892
1893 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1894                          u64 num_bytes, u64 *actual_bytes)
1895 {
1896         int ret;
1897         u64 discarded_bytes = 0;
1898         struct btrfs_bio *bbio = NULL;
1899
1900
1901         /* Tell the block device(s) that the sectors can be discarded */
1902         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1903                               bytenr, &num_bytes, &bbio, 0);
1904         /* Error condition is -ENOMEM */
1905         if (!ret) {
1906                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1907                 int i;
1908
1909
1910                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1911                         if (!stripe->dev->can_discard)
1912                                 continue;
1913
1914                         ret = btrfs_issue_discard(stripe->dev->bdev,
1915                                                   stripe->physical,
1916                                                   stripe->length);
1917                         if (!ret)
1918                                 discarded_bytes += stripe->length;
1919                         else if (ret != -EOPNOTSUPP)
1920                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1921
1922                         /*
1923                          * Just in case we get back EOPNOTSUPP for some reason,
1924                          * just ignore the return value so we don't screw up
1925                          * people calling discard_extent.
1926                          */
1927                         ret = 0;
1928                 }
1929                 btrfs_put_bbio(bbio);
1930         }
1931
1932         if (actual_bytes)
1933                 *actual_bytes = discarded_bytes;
1934
1935
1936         if (ret == -EOPNOTSUPP)
1937                 ret = 0;
1938         return ret;
1939 }
1940
1941 /* Can return -ENOMEM */
1942 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1943                          struct btrfs_root *root,
1944                          u64 bytenr, u64 num_bytes, u64 parent,
1945                          u64 root_objectid, u64 owner, u64 offset,
1946                          int no_quota)
1947 {
1948         int ret;
1949         struct btrfs_fs_info *fs_info = root->fs_info;
1950
1951         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1952                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1953
1954         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1955                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1956                                         num_bytes,
1957                                         parent, root_objectid, (int)owner,
1958                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
1959         } else {
1960                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1961                                         num_bytes,
1962                                         parent, root_objectid, owner, offset,
1963                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
1964         }
1965         return ret;
1966 }
1967
1968 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1969                                   struct btrfs_root *root,
1970                                   u64 bytenr, u64 num_bytes,
1971                                   u64 parent, u64 root_objectid,
1972                                   u64 owner, u64 offset, int refs_to_add,
1973                                   int no_quota,
1974                                   struct btrfs_delayed_extent_op *extent_op)
1975 {
1976         struct btrfs_fs_info *fs_info = root->fs_info;
1977         struct btrfs_path *path;
1978         struct extent_buffer *leaf;
1979         struct btrfs_extent_item *item;
1980         struct btrfs_key key;
1981         u64 refs;
1982         int ret;
1983         enum btrfs_qgroup_operation_type type = BTRFS_QGROUP_OPER_ADD_EXCL;
1984
1985         path = btrfs_alloc_path();
1986         if (!path)
1987                 return -ENOMEM;
1988
1989         if (!is_fstree(root_objectid) || !root->fs_info->quota_enabled)
1990                 no_quota = 1;
1991
1992         path->reada = 1;
1993         path->leave_spinning = 1;
1994         /* this will setup the path even if it fails to insert the back ref */
1995         ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
1996                                            bytenr, num_bytes, parent,
1997                                            root_objectid, owner, offset,
1998                                            refs_to_add, extent_op);
1999         if ((ret < 0 && ret != -EAGAIN) || (!ret && no_quota))
2000                 goto out;
2001         /*
2002          * Ok we were able to insert an inline extent and it appears to be a new
2003          * reference, deal with the qgroup accounting.
2004          */
2005         if (!ret && !no_quota) {
2006                 ASSERT(root->fs_info->quota_enabled);
2007                 leaf = path->nodes[0];
2008                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2009                 item = btrfs_item_ptr(leaf, path->slots[0],
2010                                       struct btrfs_extent_item);
2011                 if (btrfs_extent_refs(leaf, item) > (u64)refs_to_add)
2012                         type = BTRFS_QGROUP_OPER_ADD_SHARED;
2013                 btrfs_release_path(path);
2014
2015                 ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
2016                                               bytenr, num_bytes, type, 0);
2017                 goto out;
2018         }
2019
2020         /*
2021          * Ok we had -EAGAIN which means we didn't have space to insert and
2022          * inline extent ref, so just update the reference count and add a
2023          * normal backref.
2024          */
2025         leaf = path->nodes[0];
2026         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2027         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2028         refs = btrfs_extent_refs(leaf, item);
2029         if (refs)
2030                 type = BTRFS_QGROUP_OPER_ADD_SHARED;
2031         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2032         if (extent_op)
2033                 __run_delayed_extent_op(extent_op, leaf, item);
2034
2035         btrfs_mark_buffer_dirty(leaf);
2036         btrfs_release_path(path);
2037
2038         if (!no_quota) {
2039                 ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
2040                                               bytenr, num_bytes, type, 0);
2041                 if (ret)
2042                         goto out;
2043         }
2044
2045         path->reada = 1;
2046         path->leave_spinning = 1;
2047         /* now insert the actual backref */
2048         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2049                                     path, bytenr, parent, root_objectid,
2050                                     owner, offset, refs_to_add);
2051         if (ret)
2052                 btrfs_abort_transaction(trans, root, ret);
2053 out:
2054         btrfs_free_path(path);
2055         return ret;
2056 }
2057
2058 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2059                                 struct btrfs_root *root,
2060                                 struct btrfs_delayed_ref_node *node,
2061                                 struct btrfs_delayed_extent_op *extent_op,
2062                                 int insert_reserved)
2063 {
2064         int ret = 0;
2065         struct btrfs_delayed_data_ref *ref;
2066         struct btrfs_key ins;
2067         u64 parent = 0;
2068         u64 ref_root = 0;
2069         u64 flags = 0;
2070
2071         ins.objectid = node->bytenr;
2072         ins.offset = node->num_bytes;
2073         ins.type = BTRFS_EXTENT_ITEM_KEY;
2074
2075         ref = btrfs_delayed_node_to_data_ref(node);
2076         trace_run_delayed_data_ref(node, ref, node->action);
2077
2078         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2079                 parent = ref->parent;
2080         ref_root = ref->root;
2081
2082         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2083                 if (extent_op)
2084                         flags |= extent_op->flags_to_set;
2085                 ret = alloc_reserved_file_extent(trans, root,
2086                                                  parent, ref_root, flags,
2087                                                  ref->objectid, ref->offset,
2088                                                  &ins, node->ref_mod);
2089         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2090                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2091                                              node->num_bytes, parent,
2092                                              ref_root, ref->objectid,
2093                                              ref->offset, node->ref_mod,
2094                                              node->no_quota, extent_op);
2095         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2096                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2097                                           node->num_bytes, parent,
2098                                           ref_root, ref->objectid,
2099                                           ref->offset, node->ref_mod,
2100                                           extent_op, node->no_quota);
2101         } else {
2102                 BUG();
2103         }
2104         return ret;
2105 }
2106
2107 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2108                                     struct extent_buffer *leaf,
2109                                     struct btrfs_extent_item *ei)
2110 {
2111         u64 flags = btrfs_extent_flags(leaf, ei);
2112         if (extent_op->update_flags) {
2113                 flags |= extent_op->flags_to_set;
2114                 btrfs_set_extent_flags(leaf, ei, flags);
2115         }
2116
2117         if (extent_op->update_key) {
2118                 struct btrfs_tree_block_info *bi;
2119                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2120                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2121                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2122         }
2123 }
2124
2125 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2126                                  struct btrfs_root *root,
2127                                  struct btrfs_delayed_ref_node *node,
2128                                  struct btrfs_delayed_extent_op *extent_op)
2129 {
2130         struct btrfs_key key;
2131         struct btrfs_path *path;
2132         struct btrfs_extent_item *ei;
2133         struct extent_buffer *leaf;
2134         u32 item_size;
2135         int ret;
2136         int err = 0;
2137         int metadata = !extent_op->is_data;
2138
2139         if (trans->aborted)
2140                 return 0;
2141
2142         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2143                 metadata = 0;
2144
2145         path = btrfs_alloc_path();
2146         if (!path)
2147                 return -ENOMEM;
2148
2149         key.objectid = node->bytenr;
2150
2151         if (metadata) {
2152                 key.type = BTRFS_METADATA_ITEM_KEY;
2153                 key.offset = extent_op->level;
2154         } else {
2155                 key.type = BTRFS_EXTENT_ITEM_KEY;
2156                 key.offset = node->num_bytes;
2157         }
2158
2159 again:
2160         path->reada = 1;
2161         path->leave_spinning = 1;
2162         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2163                                 path, 0, 1);
2164         if (ret < 0) {
2165                 err = ret;
2166                 goto out;
2167         }
2168         if (ret > 0) {
2169                 if (metadata) {
2170                         if (path->slots[0] > 0) {
2171                                 path->slots[0]--;
2172                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2173                                                       path->slots[0]);
2174                                 if (key.objectid == node->bytenr &&
2175                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2176                                     key.offset == node->num_bytes)
2177                                         ret = 0;
2178                         }
2179                         if (ret > 0) {
2180                                 btrfs_release_path(path);
2181                                 metadata = 0;
2182
2183                                 key.objectid = node->bytenr;
2184                                 key.offset = node->num_bytes;
2185                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2186                                 goto again;
2187                         }
2188                 } else {
2189                         err = -EIO;
2190                         goto out;
2191                 }
2192         }
2193
2194         leaf = path->nodes[0];
2195         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2196 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2197         if (item_size < sizeof(*ei)) {
2198                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2199                                              path, (u64)-1, 0);
2200                 if (ret < 0) {
2201                         err = ret;
2202                         goto out;
2203                 }
2204                 leaf = path->nodes[0];
2205                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2206         }
2207 #endif
2208         BUG_ON(item_size < sizeof(*ei));
2209         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2210         __run_delayed_extent_op(extent_op, leaf, ei);
2211
2212         btrfs_mark_buffer_dirty(leaf);
2213 out:
2214         btrfs_free_path(path);
2215         return err;
2216 }
2217
2218 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2219                                 struct btrfs_root *root,
2220                                 struct btrfs_delayed_ref_node *node,
2221                                 struct btrfs_delayed_extent_op *extent_op,
2222                                 int insert_reserved)
2223 {
2224         int ret = 0;
2225         struct btrfs_delayed_tree_ref *ref;
2226         struct btrfs_key ins;
2227         u64 parent = 0;
2228         u64 ref_root = 0;
2229         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2230                                                  SKINNY_METADATA);
2231
2232         ref = btrfs_delayed_node_to_tree_ref(node);
2233         trace_run_delayed_tree_ref(node, ref, node->action);
2234
2235         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2236                 parent = ref->parent;
2237         ref_root = ref->root;
2238
2239         ins.objectid = node->bytenr;
2240         if (skinny_metadata) {
2241                 ins.offset = ref->level;
2242                 ins.type = BTRFS_METADATA_ITEM_KEY;
2243         } else {
2244                 ins.offset = node->num_bytes;
2245                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2246         }
2247
2248         BUG_ON(node->ref_mod != 1);
2249         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2250                 BUG_ON(!extent_op || !extent_op->update_flags);
2251                 ret = alloc_reserved_tree_block(trans, root,
2252                                                 parent, ref_root,
2253                                                 extent_op->flags_to_set,
2254                                                 &extent_op->key,
2255                                                 ref->level, &ins,
2256                                                 node->no_quota);
2257         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2258                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2259                                              node->num_bytes, parent, ref_root,
2260                                              ref->level, 0, 1, node->no_quota,
2261                                              extent_op);
2262         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2263                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2264                                           node->num_bytes, parent, ref_root,
2265                                           ref->level, 0, 1, extent_op,
2266                                           node->no_quota);
2267         } else {
2268                 BUG();
2269         }
2270         return ret;
2271 }
2272
2273 /* helper function to actually process a single delayed ref entry */
2274 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2275                                struct btrfs_root *root,
2276                                struct btrfs_delayed_ref_node *node,
2277                                struct btrfs_delayed_extent_op *extent_op,
2278                                int insert_reserved)
2279 {
2280         int ret = 0;
2281
2282         if (trans->aborted) {
2283                 if (insert_reserved)
2284                         btrfs_pin_extent(root, node->bytenr,
2285                                          node->num_bytes, 1);
2286                 return 0;
2287         }
2288
2289         if (btrfs_delayed_ref_is_head(node)) {
2290                 struct btrfs_delayed_ref_head *head;
2291                 /*
2292                  * we've hit the end of the chain and we were supposed
2293                  * to insert this extent into the tree.  But, it got
2294                  * deleted before we ever needed to insert it, so all
2295                  * we have to do is clean up the accounting
2296                  */
2297                 BUG_ON(extent_op);
2298                 head = btrfs_delayed_node_to_head(node);
2299                 trace_run_delayed_ref_head(node, head, node->action);
2300
2301                 if (insert_reserved) {
2302                         btrfs_pin_extent(root, node->bytenr,
2303                                          node->num_bytes, 1);
2304                         if (head->is_data) {
2305                                 ret = btrfs_del_csums(trans, root,
2306                                                       node->bytenr,
2307                                                       node->num_bytes);
2308                         }
2309                 }
2310                 return ret;
2311         }
2312
2313         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2314             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2315                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2316                                            insert_reserved);
2317         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2318                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2319                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2320                                            insert_reserved);
2321         else
2322                 BUG();
2323         return ret;
2324 }
2325
2326 static noinline struct btrfs_delayed_ref_node *
2327 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2328 {
2329         struct rb_node *node;
2330         struct btrfs_delayed_ref_node *ref, *last = NULL;;
2331
2332         /*
2333          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2334          * this prevents ref count from going down to zero when
2335          * there still are pending delayed ref.
2336          */
2337         node = rb_first(&head->ref_root);
2338         while (node) {
2339                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2340                                 rb_node);
2341                 if (ref->action == BTRFS_ADD_DELAYED_REF)
2342                         return ref;
2343                 else if (last == NULL)
2344                         last = ref;
2345                 node = rb_next(node);
2346         }
2347         return last;
2348 }
2349
2350 /*
2351  * Returns 0 on success or if called with an already aborted transaction.
2352  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2353  */
2354 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2355                                              struct btrfs_root *root,
2356                                              unsigned long nr)
2357 {
2358         struct btrfs_delayed_ref_root *delayed_refs;
2359         struct btrfs_delayed_ref_node *ref;
2360         struct btrfs_delayed_ref_head *locked_ref = NULL;
2361         struct btrfs_delayed_extent_op *extent_op;
2362         struct btrfs_fs_info *fs_info = root->fs_info;
2363         ktime_t start = ktime_get();
2364         int ret;
2365         unsigned long count = 0;
2366         unsigned long actual_count = 0;
2367         int must_insert_reserved = 0;
2368
2369         delayed_refs = &trans->transaction->delayed_refs;
2370         while (1) {
2371                 if (!locked_ref) {
2372                         if (count >= nr)
2373                                 break;
2374
2375                         spin_lock(&delayed_refs->lock);
2376                         locked_ref = btrfs_select_ref_head(trans);
2377                         if (!locked_ref) {
2378                                 spin_unlock(&delayed_refs->lock);
2379                                 break;
2380                         }
2381
2382                         /* grab the lock that says we are going to process
2383                          * all the refs for this head */
2384                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2385                         spin_unlock(&delayed_refs->lock);
2386                         /*
2387                          * we may have dropped the spin lock to get the head
2388                          * mutex lock, and that might have given someone else
2389                          * time to free the head.  If that's true, it has been
2390                          * removed from our list and we can move on.
2391                          */
2392                         if (ret == -EAGAIN) {
2393                                 locked_ref = NULL;
2394                                 count++;
2395                                 continue;
2396                         }
2397                 }
2398
2399                 /*
2400                  * We need to try and merge add/drops of the same ref since we
2401                  * can run into issues with relocate dropping the implicit ref
2402                  * and then it being added back again before the drop can
2403                  * finish.  If we merged anything we need to re-loop so we can
2404                  * get a good ref.
2405                  */
2406                 spin_lock(&locked_ref->lock);
2407                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2408                                          locked_ref);
2409
2410                 /*
2411                  * locked_ref is the head node, so we have to go one
2412                  * node back for any delayed ref updates
2413                  */
2414                 ref = select_delayed_ref(locked_ref);
2415
2416                 if (ref && ref->seq &&
2417                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2418                         spin_unlock(&locked_ref->lock);
2419                         btrfs_delayed_ref_unlock(locked_ref);
2420                         spin_lock(&delayed_refs->lock);
2421                         locked_ref->processing = 0;
2422                         delayed_refs->num_heads_ready++;
2423                         spin_unlock(&delayed_refs->lock);
2424                         locked_ref = NULL;
2425                         cond_resched();
2426                         count++;
2427                         continue;
2428                 }
2429
2430                 /*
2431                  * record the must insert reserved flag before we
2432                  * drop the spin lock.
2433                  */
2434                 must_insert_reserved = locked_ref->must_insert_reserved;
2435                 locked_ref->must_insert_reserved = 0;
2436
2437                 extent_op = locked_ref->extent_op;
2438                 locked_ref->extent_op = NULL;
2439
2440                 if (!ref) {
2441
2442
2443                         /* All delayed refs have been processed, Go ahead
2444                          * and send the head node to run_one_delayed_ref,
2445                          * so that any accounting fixes can happen
2446                          */
2447                         ref = &locked_ref->node;
2448
2449                         if (extent_op && must_insert_reserved) {
2450                                 btrfs_free_delayed_extent_op(extent_op);
2451                                 extent_op = NULL;
2452                         }
2453
2454                         if (extent_op) {
2455                                 spin_unlock(&locked_ref->lock);
2456                                 ret = run_delayed_extent_op(trans, root,
2457                                                             ref, extent_op);
2458                                 btrfs_free_delayed_extent_op(extent_op);
2459
2460                                 if (ret) {
2461                                         /*
2462                                          * Need to reset must_insert_reserved if
2463                                          * there was an error so the abort stuff
2464                                          * can cleanup the reserved space
2465                                          * properly.
2466                                          */
2467                                         if (must_insert_reserved)
2468                                                 locked_ref->must_insert_reserved = 1;
2469                                         locked_ref->processing = 0;
2470                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2471                                         btrfs_delayed_ref_unlock(locked_ref);
2472                                         return ret;
2473                                 }
2474                                 continue;
2475                         }
2476
2477                         /*
2478                          * Need to drop our head ref lock and re-aqcuire the
2479                          * delayed ref lock and then re-check to make sure
2480                          * nobody got added.
2481                          */
2482                         spin_unlock(&locked_ref->lock);
2483                         spin_lock(&delayed_refs->lock);
2484                         spin_lock(&locked_ref->lock);
2485                         if (rb_first(&locked_ref->ref_root) ||
2486                             locked_ref->extent_op) {
2487                                 spin_unlock(&locked_ref->lock);
2488                                 spin_unlock(&delayed_refs->lock);
2489                                 continue;
2490                         }
2491                         ref->in_tree = 0;
2492                         delayed_refs->num_heads--;
2493                         rb_erase(&locked_ref->href_node,
2494                                  &delayed_refs->href_root);
2495                         spin_unlock(&delayed_refs->lock);
2496                 } else {
2497                         actual_count++;
2498                         ref->in_tree = 0;
2499                         rb_erase(&ref->rb_node, &locked_ref->ref_root);
2500                 }
2501                 atomic_dec(&delayed_refs->num_entries);
2502
2503                 if (!btrfs_delayed_ref_is_head(ref)) {
2504                         /*
2505                          * when we play the delayed ref, also correct the
2506                          * ref_mod on head
2507                          */
2508                         switch (ref->action) {
2509                         case BTRFS_ADD_DELAYED_REF:
2510                         case BTRFS_ADD_DELAYED_EXTENT:
2511                                 locked_ref->node.ref_mod -= ref->ref_mod;
2512                                 break;
2513                         case BTRFS_DROP_DELAYED_REF:
2514                                 locked_ref->node.ref_mod += ref->ref_mod;
2515                                 break;
2516                         default:
2517                                 WARN_ON(1);
2518                         }
2519                 }
2520                 spin_unlock(&locked_ref->lock);
2521
2522                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2523                                           must_insert_reserved);
2524
2525                 btrfs_free_delayed_extent_op(extent_op);
2526                 if (ret) {
2527                         locked_ref->processing = 0;
2528                         btrfs_delayed_ref_unlock(locked_ref);
2529                         btrfs_put_delayed_ref(ref);
2530                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2531                         return ret;
2532                 }
2533
2534                 /*
2535                  * If this node is a head, that means all the refs in this head
2536                  * have been dealt with, and we will pick the next head to deal
2537                  * with, so we must unlock the head and drop it from the cluster
2538                  * list before we release it.
2539                  */
2540                 if (btrfs_delayed_ref_is_head(ref)) {
2541                         btrfs_delayed_ref_unlock(locked_ref);
2542                         locked_ref = NULL;
2543                 }
2544                 btrfs_put_delayed_ref(ref);
2545                 count++;
2546                 cond_resched();
2547         }
2548
2549         /*
2550          * We don't want to include ref heads since we can have empty ref heads
2551          * and those will drastically skew our runtime down since we just do
2552          * accounting, no actual extent tree updates.
2553          */
2554         if (actual_count > 0) {
2555                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2556                 u64 avg;
2557
2558                 /*
2559                  * We weigh the current average higher than our current runtime
2560                  * to avoid large swings in the average.
2561                  */
2562                 spin_lock(&delayed_refs->lock);
2563                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2564                 avg = div64_u64(avg, 4);
2565                 fs_info->avg_delayed_ref_runtime = avg;
2566                 spin_unlock(&delayed_refs->lock);
2567         }
2568         return 0;
2569 }
2570
2571 #ifdef SCRAMBLE_DELAYED_REFS
2572 /*
2573  * Normally delayed refs get processed in ascending bytenr order. This
2574  * correlates in most cases to the order added. To expose dependencies on this
2575  * order, we start to process the tree in the middle instead of the beginning
2576  */
2577 static u64 find_middle(struct rb_root *root)
2578 {
2579         struct rb_node *n = root->rb_node;
2580         struct btrfs_delayed_ref_node *entry;
2581         int alt = 1;
2582         u64 middle;
2583         u64 first = 0, last = 0;
2584
2585         n = rb_first(root);
2586         if (n) {
2587                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2588                 first = entry->bytenr;
2589         }
2590         n = rb_last(root);
2591         if (n) {
2592                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2593                 last = entry->bytenr;
2594         }
2595         n = root->rb_node;
2596
2597         while (n) {
2598                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2599                 WARN_ON(!entry->in_tree);
2600
2601                 middle = entry->bytenr;
2602
2603                 if (alt)
2604                         n = n->rb_left;
2605                 else
2606                         n = n->rb_right;
2607
2608                 alt = 1 - alt;
2609         }
2610         return middle;
2611 }
2612 #endif
2613
2614 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2615 {
2616         u64 num_bytes;
2617
2618         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2619                              sizeof(struct btrfs_extent_inline_ref));
2620         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2621                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2622
2623         /*
2624          * We don't ever fill up leaves all the way so multiply by 2 just to be
2625          * closer to what we're really going to want to ouse.
2626          */
2627         return div64_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2628 }
2629
2630 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2631                                        struct btrfs_root *root)
2632 {
2633         struct btrfs_block_rsv *global_rsv;
2634         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2635         u64 num_bytes;
2636         int ret = 0;
2637
2638         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2639         num_heads = heads_to_leaves(root, num_heads);
2640         if (num_heads > 1)
2641                 num_bytes += (num_heads - 1) * root->nodesize;
2642         num_bytes <<= 1;
2643         global_rsv = &root->fs_info->global_block_rsv;
2644
2645         /*
2646          * If we can't allocate any more chunks lets make sure we have _lots_ of
2647          * wiggle room since running delayed refs can create more delayed refs.
2648          */
2649         if (global_rsv->space_info->full)
2650                 num_bytes <<= 1;
2651
2652         spin_lock(&global_rsv->lock);
2653         if (global_rsv->reserved <= num_bytes)
2654                 ret = 1;
2655         spin_unlock(&global_rsv->lock);
2656         return ret;
2657 }
2658
2659 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2660                                        struct btrfs_root *root)
2661 {
2662         struct btrfs_fs_info *fs_info = root->fs_info;
2663         u64 num_entries =
2664                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2665         u64 avg_runtime;
2666         u64 val;
2667
2668         smp_mb();
2669         avg_runtime = fs_info->avg_delayed_ref_runtime;
2670         val = num_entries * avg_runtime;
2671         if (num_entries * avg_runtime >= NSEC_PER_SEC)
2672                 return 1;
2673         if (val >= NSEC_PER_SEC / 2)
2674                 return 2;
2675
2676         return btrfs_check_space_for_delayed_refs(trans, root);
2677 }
2678
2679 struct async_delayed_refs {
2680         struct btrfs_root *root;
2681         int count;
2682         int error;
2683         int sync;
2684         struct completion wait;
2685         struct btrfs_work work;
2686 };
2687
2688 static void delayed_ref_async_start(struct btrfs_work *work)
2689 {
2690         struct async_delayed_refs *async;
2691         struct btrfs_trans_handle *trans;
2692         int ret;
2693
2694         async = container_of(work, struct async_delayed_refs, work);
2695
2696         trans = btrfs_join_transaction(async->root);
2697         if (IS_ERR(trans)) {
2698                 async->error = PTR_ERR(trans);
2699                 goto done;
2700         }
2701
2702         /*
2703          * trans->sync means that when we call end_transaciton, we won't
2704          * wait on delayed refs
2705          */
2706         trans->sync = true;
2707         ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2708         if (ret)
2709                 async->error = ret;
2710
2711         ret = btrfs_end_transaction(trans, async->root);
2712         if (ret && !async->error)
2713                 async->error = ret;
2714 done:
2715         if (async->sync)
2716                 complete(&async->wait);
2717         else
2718                 kfree(async);
2719 }
2720
2721 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2722                                  unsigned long count, int wait)
2723 {
2724         struct async_delayed_refs *async;
2725         int ret;
2726
2727         async = kmalloc(sizeof(*async), GFP_NOFS);
2728         if (!async)
2729                 return -ENOMEM;
2730
2731         async->root = root->fs_info->tree_root;
2732         async->count = count;
2733         async->error = 0;
2734         if (wait)
2735                 async->sync = 1;
2736         else
2737                 async->sync = 0;
2738         init_completion(&async->wait);
2739
2740         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2741                         delayed_ref_async_start, NULL, NULL);
2742
2743         btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2744
2745         if (wait) {
2746                 wait_for_completion(&async->wait);
2747                 ret = async->error;
2748                 kfree(async);
2749                 return ret;
2750         }
2751         return 0;
2752 }
2753
2754 /*
2755  * this starts processing the delayed reference count updates and
2756  * extent insertions we have queued up so far.  count can be
2757  * 0, which means to process everything in the tree at the start
2758  * of the run (but not newly added entries), or it can be some target
2759  * number you'd like to process.
2760  *
2761  * Returns 0 on success or if called with an aborted transaction
2762  * Returns <0 on error and aborts the transaction
2763  */
2764 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2765                            struct btrfs_root *root, unsigned long count)
2766 {
2767         struct rb_node *node;
2768         struct btrfs_delayed_ref_root *delayed_refs;
2769         struct btrfs_delayed_ref_head *head;
2770         int ret;
2771         int run_all = count == (unsigned long)-1;
2772
2773         /* We'll clean this up in btrfs_cleanup_transaction */
2774         if (trans->aborted)
2775                 return 0;
2776
2777         if (root == root->fs_info->extent_root)
2778                 root = root->fs_info->tree_root;
2779
2780         delayed_refs = &trans->transaction->delayed_refs;
2781         if (count == 0)
2782                 count = atomic_read(&delayed_refs->num_entries) * 2;
2783
2784 again:
2785 #ifdef SCRAMBLE_DELAYED_REFS
2786         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2787 #endif
2788         ret = __btrfs_run_delayed_refs(trans, root, count);
2789         if (ret < 0) {
2790                 btrfs_abort_transaction(trans, root, ret);
2791                 return ret;
2792         }
2793
2794         if (run_all) {
2795                 if (!list_empty(&trans->new_bgs))
2796                         btrfs_create_pending_block_groups(trans, root);
2797
2798                 spin_lock(&delayed_refs->lock);
2799                 node = rb_first(&delayed_refs->href_root);
2800                 if (!node) {
2801                         spin_unlock(&delayed_refs->lock);
2802                         goto out;
2803                 }
2804                 count = (unsigned long)-1;
2805
2806                 while (node) {
2807                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2808                                         href_node);
2809                         if (btrfs_delayed_ref_is_head(&head->node)) {
2810                                 struct btrfs_delayed_ref_node *ref;
2811
2812                                 ref = &head->node;
2813                                 atomic_inc(&ref->refs);
2814
2815                                 spin_unlock(&delayed_refs->lock);
2816                                 /*
2817                                  * Mutex was contended, block until it's
2818                                  * released and try again
2819                                  */
2820                                 mutex_lock(&head->mutex);
2821                                 mutex_unlock(&head->mutex);
2822
2823                                 btrfs_put_delayed_ref(ref);
2824                                 cond_resched();
2825                                 goto again;
2826                         } else {
2827                                 WARN_ON(1);
2828                         }
2829                         node = rb_next(node);
2830                 }
2831                 spin_unlock(&delayed_refs->lock);
2832                 cond_resched();
2833                 goto again;
2834         }
2835 out:
2836         ret = btrfs_delayed_qgroup_accounting(trans, root->fs_info);
2837         if (ret)
2838                 return ret;
2839         assert_qgroups_uptodate(trans);
2840         return 0;
2841 }
2842
2843 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2844                                 struct btrfs_root *root,
2845                                 u64 bytenr, u64 num_bytes, u64 flags,
2846                                 int level, int is_data)
2847 {
2848         struct btrfs_delayed_extent_op *extent_op;
2849         int ret;
2850
2851         extent_op = btrfs_alloc_delayed_extent_op();
2852         if (!extent_op)
2853                 return -ENOMEM;
2854
2855         extent_op->flags_to_set = flags;
2856         extent_op->update_flags = 1;
2857         extent_op->update_key = 0;
2858         extent_op->is_data = is_data ? 1 : 0;
2859         extent_op->level = level;
2860
2861         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2862                                           num_bytes, extent_op);
2863         if (ret)
2864                 btrfs_free_delayed_extent_op(extent_op);
2865         return ret;
2866 }
2867
2868 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2869                                       struct btrfs_root *root,
2870                                       struct btrfs_path *path,
2871                                       u64 objectid, u64 offset, u64 bytenr)
2872 {
2873         struct btrfs_delayed_ref_head *head;
2874         struct btrfs_delayed_ref_node *ref;
2875         struct btrfs_delayed_data_ref *data_ref;
2876         struct btrfs_delayed_ref_root *delayed_refs;
2877         struct rb_node *node;
2878         int ret = 0;
2879
2880         delayed_refs = &trans->transaction->delayed_refs;
2881         spin_lock(&delayed_refs->lock);
2882         head = btrfs_find_delayed_ref_head(trans, bytenr);
2883         if (!head) {
2884                 spin_unlock(&delayed_refs->lock);
2885                 return 0;
2886         }
2887
2888         if (!mutex_trylock(&head->mutex)) {
2889                 atomic_inc(&head->node.refs);
2890                 spin_unlock(&delayed_refs->lock);
2891
2892                 btrfs_release_path(path);
2893
2894                 /*
2895                  * Mutex was contended, block until it's released and let
2896                  * caller try again
2897                  */
2898                 mutex_lock(&head->mutex);
2899                 mutex_unlock(&head->mutex);
2900                 btrfs_put_delayed_ref(&head->node);
2901                 return -EAGAIN;
2902         }
2903         spin_unlock(&delayed_refs->lock);
2904
2905         spin_lock(&head->lock);
2906         node = rb_first(&head->ref_root);
2907         while (node) {
2908                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2909                 node = rb_next(node);
2910
2911                 /* If it's a shared ref we know a cross reference exists */
2912                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2913                         ret = 1;
2914                         break;
2915                 }
2916
2917                 data_ref = btrfs_delayed_node_to_data_ref(ref);
2918
2919                 /*
2920                  * If our ref doesn't match the one we're currently looking at
2921                  * then we have a cross reference.
2922                  */
2923                 if (data_ref->root != root->root_key.objectid ||
2924                     data_ref->objectid != objectid ||
2925                     data_ref->offset != offset) {
2926                         ret = 1;
2927                         break;
2928                 }
2929         }
2930         spin_unlock(&head->lock);
2931         mutex_unlock(&head->mutex);
2932         return ret;
2933 }
2934
2935 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2936                                         struct btrfs_root *root,
2937                                         struct btrfs_path *path,
2938                                         u64 objectid, u64 offset, u64 bytenr)
2939 {
2940         struct btrfs_root *extent_root = root->fs_info->extent_root;
2941         struct extent_buffer *leaf;
2942         struct btrfs_extent_data_ref *ref;
2943         struct btrfs_extent_inline_ref *iref;
2944         struct btrfs_extent_item *ei;
2945         struct btrfs_key key;
2946         u32 item_size;
2947         int ret;
2948
2949         key.objectid = bytenr;
2950         key.offset = (u64)-1;
2951         key.type = BTRFS_EXTENT_ITEM_KEY;
2952
2953         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2954         if (ret < 0)
2955                 goto out;
2956         BUG_ON(ret == 0); /* Corruption */
2957
2958         ret = -ENOENT;
2959         if (path->slots[0] == 0)
2960                 goto out;
2961
2962         path->slots[0]--;
2963         leaf = path->nodes[0];
2964         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2965
2966         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2967                 goto out;
2968
2969         ret = 1;
2970         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2971 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2972         if (item_size < sizeof(*ei)) {
2973                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2974                 goto out;
2975         }
2976 #endif
2977         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2978
2979         if (item_size != sizeof(*ei) +
2980             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2981                 goto out;
2982
2983         if (btrfs_extent_generation(leaf, ei) <=
2984             btrfs_root_last_snapshot(&root->root_item))
2985                 goto out;
2986
2987         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2988         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2989             BTRFS_EXTENT_DATA_REF_KEY)
2990                 goto out;
2991
2992         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2993         if (btrfs_extent_refs(leaf, ei) !=
2994             btrfs_extent_data_ref_count(leaf, ref) ||
2995             btrfs_extent_data_ref_root(leaf, ref) !=
2996             root->root_key.objectid ||
2997             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2998             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2999                 goto out;
3000
3001         ret = 0;
3002 out:
3003         return ret;
3004 }
3005
3006 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3007                           struct btrfs_root *root,
3008                           u64 objectid, u64 offset, u64 bytenr)
3009 {
3010         struct btrfs_path *path;
3011         int ret;
3012         int ret2;
3013
3014         path = btrfs_alloc_path();
3015         if (!path)
3016                 return -ENOENT;
3017
3018         do {
3019                 ret = check_committed_ref(trans, root, path, objectid,
3020                                           offset, bytenr);
3021                 if (ret && ret != -ENOENT)
3022                         goto out;
3023
3024                 ret2 = check_delayed_ref(trans, root, path, objectid,
3025                                          offset, bytenr);
3026         } while (ret2 == -EAGAIN);
3027
3028         if (ret2 && ret2 != -ENOENT) {
3029                 ret = ret2;
3030                 goto out;
3031         }
3032
3033         if (ret != -ENOENT || ret2 != -ENOENT)
3034                 ret = 0;
3035 out:
3036         btrfs_free_path(path);
3037         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3038                 WARN_ON(ret > 0);
3039         return ret;
3040 }
3041
3042 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3043                            struct btrfs_root *root,
3044                            struct extent_buffer *buf,
3045                            int full_backref, int inc)
3046 {
3047         u64 bytenr;
3048         u64 num_bytes;
3049         u64 parent;
3050         u64 ref_root;
3051         u32 nritems;
3052         struct btrfs_key key;
3053         struct btrfs_file_extent_item *fi;
3054         int i;
3055         int level;
3056         int ret = 0;
3057         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3058                             u64, u64, u64, u64, u64, u64, int);
3059
3060
3061         if (btrfs_test_is_dummy_root(root))
3062                 return 0;
3063
3064         ref_root = btrfs_header_owner(buf);
3065         nritems = btrfs_header_nritems(buf);
3066         level = btrfs_header_level(buf);
3067
3068         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3069                 return 0;
3070
3071         if (inc)
3072                 process_func = btrfs_inc_extent_ref;
3073         else
3074                 process_func = btrfs_free_extent;
3075
3076         if (full_backref)
3077                 parent = buf->start;
3078         else
3079                 parent = 0;
3080
3081         for (i = 0; i < nritems; i++) {
3082                 if (level == 0) {
3083                         btrfs_item_key_to_cpu(buf, &key, i);
3084                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3085                                 continue;
3086                         fi = btrfs_item_ptr(buf, i,
3087                                             struct btrfs_file_extent_item);
3088                         if (btrfs_file_extent_type(buf, fi) ==
3089                             BTRFS_FILE_EXTENT_INLINE)
3090                                 continue;
3091                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3092                         if (bytenr == 0)
3093                                 continue;
3094
3095                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3096                         key.offset -= btrfs_file_extent_offset(buf, fi);
3097                         ret = process_func(trans, root, bytenr, num_bytes,
3098                                            parent, ref_root, key.objectid,
3099                                            key.offset, 1);
3100                         if (ret)
3101                                 goto fail;
3102                 } else {
3103                         bytenr = btrfs_node_blockptr(buf, i);
3104                         num_bytes = root->nodesize;
3105                         ret = process_func(trans, root, bytenr, num_bytes,
3106                                            parent, ref_root, level - 1, 0,
3107                                            1);
3108                         if (ret)
3109                                 goto fail;
3110                 }
3111         }
3112         return 0;
3113 fail:
3114         return ret;
3115 }
3116
3117 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3118                   struct extent_buffer *buf, int full_backref)
3119 {
3120         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3121 }
3122
3123 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3124                   struct extent_buffer *buf, int full_backref)
3125 {
3126         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3127 }
3128
3129 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3130                                  struct btrfs_root *root,
3131                                  struct btrfs_path *path,
3132                                  struct btrfs_block_group_cache *cache)
3133 {
3134         int ret;
3135         struct btrfs_root *extent_root = root->fs_info->extent_root;
3136         unsigned long bi;
3137         struct extent_buffer *leaf;
3138
3139         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3140         if (ret) {
3141                 if (ret > 0)
3142                         ret = -ENOENT;
3143                 goto fail;
3144         }
3145
3146         leaf = path->nodes[0];
3147         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3148         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3149         btrfs_mark_buffer_dirty(leaf);
3150         btrfs_release_path(path);
3151 fail:
3152         if (ret)
3153                 btrfs_abort_transaction(trans, root, ret);
3154         return ret;
3155
3156 }
3157
3158 static struct btrfs_block_group_cache *
3159 next_block_group(struct btrfs_root *root,
3160                  struct btrfs_block_group_cache *cache)
3161 {
3162         struct rb_node *node;
3163
3164         spin_lock(&root->fs_info->block_group_cache_lock);
3165
3166         /* If our block group was removed, we need a full search. */
3167         if (RB_EMPTY_NODE(&cache->cache_node)) {
3168                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3169
3170                 spin_unlock(&root->fs_info->block_group_cache_lock);
3171                 btrfs_put_block_group(cache);
3172                 cache = btrfs_lookup_first_block_group(root->fs_info,
3173                                                        next_bytenr);
3174                 return cache;
3175         }
3176         node = rb_next(&cache->cache_node);
3177         btrfs_put_block_group(cache);
3178         if (node) {
3179                 cache = rb_entry(node, struct btrfs_block_group_cache,
3180                                  cache_node);
3181                 btrfs_get_block_group(cache);
3182         } else
3183                 cache = NULL;
3184         spin_unlock(&root->fs_info->block_group_cache_lock);
3185         return cache;
3186 }
3187
3188 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3189                             struct btrfs_trans_handle *trans,
3190                             struct btrfs_path *path)
3191 {
3192         struct btrfs_root *root = block_group->fs_info->tree_root;
3193         struct inode *inode = NULL;
3194         u64 alloc_hint = 0;
3195         int dcs = BTRFS_DC_ERROR;
3196         int num_pages = 0;
3197         int retries = 0;
3198         int ret = 0;
3199
3200         /*
3201          * If this block group is smaller than 100 megs don't bother caching the
3202          * block group.
3203          */
3204         if (block_group->key.offset < (100 * 1024 * 1024)) {
3205                 spin_lock(&block_group->lock);
3206                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3207                 spin_unlock(&block_group->lock);
3208                 return 0;
3209         }
3210
3211 again:
3212         inode = lookup_free_space_inode(root, block_group, path);
3213         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3214                 ret = PTR_ERR(inode);
3215                 btrfs_release_path(path);
3216                 goto out;
3217         }
3218
3219         if (IS_ERR(inode)) {
3220                 BUG_ON(retries);
3221                 retries++;
3222
3223                 if (block_group->ro)
3224                         goto out_free;
3225
3226                 ret = create_free_space_inode(root, trans, block_group, path);
3227                 if (ret)
3228                         goto out_free;
3229                 goto again;
3230         }
3231
3232         /* We've already setup this transaction, go ahead and exit */
3233         if (block_group->cache_generation == trans->transid &&
3234             i_size_read(inode)) {
3235                 dcs = BTRFS_DC_SETUP;
3236                 goto out_put;
3237         }
3238
3239         /*
3240          * We want to set the generation to 0, that way if anything goes wrong
3241          * from here on out we know not to trust this cache when we load up next
3242          * time.
3243          */
3244         BTRFS_I(inode)->generation = 0;
3245         ret = btrfs_update_inode(trans, root, inode);
3246         WARN_ON(ret);
3247
3248         if (i_size_read(inode) > 0) {
3249                 ret = btrfs_check_trunc_cache_free_space(root,
3250                                         &root->fs_info->global_block_rsv);
3251                 if (ret)
3252                         goto out_put;
3253
3254                 ret = btrfs_truncate_free_space_cache(root, trans, inode);
3255                 if (ret)
3256                         goto out_put;
3257         }
3258
3259         spin_lock(&block_group->lock);
3260         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3261             !btrfs_test_opt(root, SPACE_CACHE) ||
3262             block_group->delalloc_bytes) {
3263                 /*
3264                  * don't bother trying to write stuff out _if_
3265                  * a) we're not cached,
3266                  * b) we're with nospace_cache mount option.
3267                  */
3268                 dcs = BTRFS_DC_WRITTEN;
3269                 spin_unlock(&block_group->lock);
3270                 goto out_put;
3271         }
3272         spin_unlock(&block_group->lock);
3273
3274         /*
3275          * Try to preallocate enough space based on how big the block group is.
3276          * Keep in mind this has to include any pinned space which could end up
3277          * taking up quite a bit since it's not folded into the other space
3278          * cache.
3279          */
3280         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3281         if (!num_pages)
3282                 num_pages = 1;
3283
3284         num_pages *= 16;
3285         num_pages *= PAGE_CACHE_SIZE;
3286
3287         ret = btrfs_check_data_free_space(inode, num_pages);
3288         if (ret)
3289                 goto out_put;
3290
3291         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3292                                               num_pages, num_pages,
3293                                               &alloc_hint);
3294         if (!ret)
3295                 dcs = BTRFS_DC_SETUP;
3296         btrfs_free_reserved_data_space(inode, num_pages);
3297
3298 out_put:
3299         iput(inode);
3300 out_free:
3301         btrfs_release_path(path);
3302 out:
3303         spin_lock(&block_group->lock);
3304         if (!ret && dcs == BTRFS_DC_SETUP)
3305                 block_group->cache_generation = trans->transid;
3306         block_group->disk_cache_state = dcs;
3307         spin_unlock(&block_group->lock);
3308
3309         return ret;
3310 }
3311
3312 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3313                                    struct btrfs_root *root)
3314 {
3315         struct btrfs_block_group_cache *cache;
3316         struct btrfs_transaction *cur_trans = trans->transaction;
3317         int ret = 0;
3318         struct btrfs_path *path;
3319
3320         if (list_empty(&cur_trans->dirty_bgs))
3321                 return 0;
3322
3323         path = btrfs_alloc_path();
3324         if (!path)
3325                 return -ENOMEM;
3326
3327         /*
3328          * We don't need the lock here since we are protected by the transaction
3329          * commit.  We want to do the cache_save_setup first and then run the
3330          * delayed refs to make sure we have the best chance at doing this all
3331          * in one shot.
3332          */
3333         while (!list_empty(&cur_trans->dirty_bgs)) {
3334                 cache = list_first_entry(&cur_trans->dirty_bgs,
3335                                          struct btrfs_block_group_cache,
3336                                          dirty_list);
3337                 list_del_init(&cache->dirty_list);
3338                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3339                         cache_save_setup(cache, trans, path);
3340                 if (!ret)
3341                         ret = btrfs_run_delayed_refs(trans, root,
3342                                                      (unsigned long) -1);
3343                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP)
3344                         btrfs_write_out_cache(root, trans, cache, path);
3345                 if (!ret)
3346                         ret = write_one_cache_group(trans, root, path, cache);
3347                 btrfs_put_block_group(cache);
3348         }
3349
3350         btrfs_free_path(path);
3351         return ret;
3352 }
3353
3354 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3355 {
3356         struct btrfs_block_group_cache *block_group;
3357         int readonly = 0;
3358
3359         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3360         if (!block_group || block_group->ro)
3361                 readonly = 1;
3362         if (block_group)
3363                 btrfs_put_block_group(block_group);
3364         return readonly;
3365 }
3366
3367 static const char *alloc_name(u64 flags)
3368 {
3369         switch (flags) {
3370         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3371                 return "mixed";
3372         case BTRFS_BLOCK_GROUP_METADATA:
3373                 return "metadata";
3374         case BTRFS_BLOCK_GROUP_DATA:
3375                 return "data";
3376         case BTRFS_BLOCK_GROUP_SYSTEM:
3377                 return "system";
3378         default:
3379                 WARN_ON(1);
3380                 return "invalid-combination";
3381         };
3382 }
3383
3384 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3385                              u64 total_bytes, u64 bytes_used,
3386                              struct btrfs_space_info **space_info)
3387 {
3388         struct btrfs_space_info *found;
3389         int i;
3390         int factor;
3391         int ret;
3392
3393         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3394                      BTRFS_BLOCK_GROUP_RAID10))
3395                 factor = 2;
3396         else
3397                 factor = 1;
3398
3399         found = __find_space_info(info, flags);
3400         if (found) {
3401                 spin_lock(&found->lock);
3402                 found->total_bytes += total_bytes;
3403                 found->disk_total += total_bytes * factor;
3404                 found->bytes_used += bytes_used;
3405                 found->disk_used += bytes_used * factor;
3406                 found->full = 0;
3407                 spin_unlock(&found->lock);
3408                 *space_info = found;
3409                 return 0;
3410         }
3411         found = kzalloc(sizeof(*found), GFP_NOFS);
3412         if (!found)
3413                 return -ENOMEM;
3414
3415         ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3416         if (ret) {
3417                 kfree(found);
3418                 return ret;
3419         }
3420
3421         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3422                 INIT_LIST_HEAD(&found->block_groups[i]);
3423         init_rwsem(&found->groups_sem);
3424         spin_lock_init(&found->lock);
3425         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3426         found->total_bytes = total_bytes;
3427         found->disk_total = total_bytes * factor;
3428         found->bytes_used = bytes_used;
3429         found->disk_used = bytes_used * factor;
3430         found->bytes_pinned = 0;
3431         found->bytes_reserved = 0;
3432         found->bytes_readonly = 0;
3433         found->bytes_may_use = 0;
3434         found->full = 0;
3435         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3436         found->chunk_alloc = 0;
3437         found->flush = 0;
3438         init_waitqueue_head(&found->wait);
3439         INIT_LIST_HEAD(&found->ro_bgs);
3440
3441         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3442                                     info->space_info_kobj, "%s",
3443                                     alloc_name(found->flags));
3444         if (ret) {
3445                 kfree(found);
3446                 return ret;
3447         }
3448
3449         *space_info = found;
3450         list_add_rcu(&found->list, &info->space_info);
3451         if (flags & BTRFS_BLOCK_GROUP_DATA)
3452                 info->data_sinfo = found;
3453
3454         return ret;
3455 }
3456
3457 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3458 {
3459         u64 extra_flags = chunk_to_extended(flags) &
3460                                 BTRFS_EXTENDED_PROFILE_MASK;
3461
3462         write_seqlock(&fs_info->profiles_lock);
3463         if (flags & BTRFS_BLOCK_GROUP_DATA)
3464                 fs_info->avail_data_alloc_bits |= extra_flags;
3465         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3466                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3467         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3468                 fs_info->avail_system_alloc_bits |= extra_flags;
3469         write_sequnlock(&fs_info->profiles_lock);
3470 }
3471
3472 /*
3473  * returns target flags in extended format or 0 if restripe for this
3474  * chunk_type is not in progress
3475  *
3476  * should be called with either volume_mutex or balance_lock held
3477  */
3478 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3479 {
3480         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3481         u64 target = 0;
3482
3483         if (!bctl)
3484                 return 0;
3485
3486         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3487             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3488                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3489         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3490                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3491                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3492         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3493                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3494                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3495         }
3496
3497         return target;
3498 }
3499
3500 /*
3501  * @flags: available profiles in extended format (see ctree.h)
3502  *
3503  * Returns reduced profile in chunk format.  If profile changing is in
3504  * progress (either running or paused) picks the target profile (if it's
3505  * already available), otherwise falls back to plain reducing.
3506  */
3507 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3508 {
3509         u64 num_devices = root->fs_info->fs_devices->rw_devices;
3510         u64 target;
3511         u64 tmp;
3512
3513         /*
3514          * see if restripe for this chunk_type is in progress, if so
3515          * try to reduce to the target profile
3516          */
3517         spin_lock(&root->fs_info->balance_lock);
3518         target = get_restripe_target(root->fs_info, flags);
3519         if (target) {
3520                 /* pick target profile only if it's already available */
3521                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3522                         spin_unlock(&root->fs_info->balance_lock);
3523                         return extended_to_chunk(target);
3524                 }
3525         }
3526         spin_unlock(&root->fs_info->balance_lock);
3527
3528         /* First, mask out the RAID levels which aren't possible */
3529         if (num_devices == 1)
3530                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3531                            BTRFS_BLOCK_GROUP_RAID5);
3532         if (num_devices < 3)
3533                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3534         if (num_devices < 4)
3535                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3536
3537         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3538                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3539                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3540         flags &= ~tmp;
3541
3542         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3543                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3544         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3545                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3546         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3547                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3548         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3549                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3550         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3551                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3552
3553         return extended_to_chunk(flags | tmp);
3554 }
3555
3556 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
3557 {
3558         unsigned seq;
3559         u64 flags;
3560
3561         do {
3562                 flags = orig_flags;
3563                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3564
3565                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3566                         flags |= root->fs_info->avail_data_alloc_bits;
3567                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3568                         flags |= root->fs_info->avail_system_alloc_bits;
3569                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3570                         flags |= root->fs_info->avail_metadata_alloc_bits;
3571         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3572
3573         return btrfs_reduce_alloc_profile(root, flags);
3574 }
3575
3576 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3577 {
3578         u64 flags;
3579         u64 ret;
3580
3581         if (data)
3582                 flags = BTRFS_BLOCK_GROUP_DATA;
3583         else if (root == root->fs_info->chunk_root)
3584                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3585         else
3586                 flags = BTRFS_BLOCK_GROUP_METADATA;
3587
3588         ret = get_alloc_profile(root, flags);
3589         return ret;
3590 }
3591
3592 /*
3593  * This will check the space that the inode allocates from to make sure we have
3594  * enough space for bytes.
3595  */
3596 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3597 {
3598         struct btrfs_space_info *data_sinfo;
3599         struct btrfs_root *root = BTRFS_I(inode)->root;
3600         struct btrfs_fs_info *fs_info = root->fs_info;
3601         u64 used;
3602         int ret = 0, committed = 0, alloc_chunk = 1;
3603
3604         /* make sure bytes are sectorsize aligned */
3605         bytes = ALIGN(bytes, root->sectorsize);
3606
3607         if (btrfs_is_free_space_inode(inode)) {
3608                 committed = 1;
3609                 ASSERT(current->journal_info);
3610         }
3611
3612         data_sinfo = fs_info->data_sinfo;
3613         if (!data_sinfo)
3614                 goto alloc;
3615
3616 again:
3617         /* make sure we have enough space to handle the data first */
3618         spin_lock(&data_sinfo->lock);
3619         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3620                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3621                 data_sinfo->bytes_may_use;
3622
3623         if (used + bytes > data_sinfo->total_bytes) {
3624                 struct btrfs_trans_handle *trans;
3625
3626                 /*
3627                  * if we don't have enough free bytes in this space then we need
3628                  * to alloc a new chunk.
3629                  */
3630                 if (!data_sinfo->full && alloc_chunk) {
3631                         u64 alloc_target;
3632
3633                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3634                         spin_unlock(&data_sinfo->lock);
3635 alloc:
3636                         alloc_target = btrfs_get_alloc_profile(root, 1);
3637                         /*
3638                          * It is ugly that we don't call nolock join
3639                          * transaction for the free space inode case here.
3640                          * But it is safe because we only do the data space
3641                          * reservation for the free space cache in the
3642                          * transaction context, the common join transaction
3643                          * just increase the counter of the current transaction
3644                          * handler, doesn't try to acquire the trans_lock of
3645                          * the fs.
3646                          */
3647                         trans = btrfs_join_transaction(root);
3648                         if (IS_ERR(trans))
3649                                 return PTR_ERR(trans);
3650
3651                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3652                                              alloc_target,
3653                                              CHUNK_ALLOC_NO_FORCE);
3654                         btrfs_end_transaction(trans, root);
3655                         if (ret < 0) {
3656                                 if (ret != -ENOSPC)
3657                                         return ret;
3658                                 else
3659                                         goto commit_trans;
3660                         }
3661
3662                         if (!data_sinfo)
3663                                 data_sinfo = fs_info->data_sinfo;
3664
3665                         goto again;
3666                 }
3667
3668                 /*
3669                  * If we don't have enough pinned space to deal with this
3670                  * allocation don't bother committing the transaction.
3671                  */
3672                 if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
3673                                            bytes) < 0)
3674                         committed = 1;
3675                 spin_unlock(&data_sinfo->lock);
3676
3677                 /* commit the current transaction and try again */
3678 commit_trans:
3679                 if (!committed &&
3680                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3681                         committed = 1;
3682
3683                         trans = btrfs_join_transaction(root);
3684                         if (IS_ERR(trans))
3685                                 return PTR_ERR(trans);
3686                         ret = btrfs_commit_transaction(trans, root);
3687                         if (ret)
3688                                 return ret;
3689                         goto again;
3690                 }
3691
3692                 trace_btrfs_space_reservation(root->fs_info,
3693                                               "space_info:enospc",
3694                                               data_sinfo->flags, bytes, 1);
3695                 return -ENOSPC;
3696         }
3697         data_sinfo->bytes_may_use += bytes;
3698         trace_btrfs_space_reservation(root->fs_info, "space_info",
3699                                       data_sinfo->flags, bytes, 1);
3700         spin_unlock(&data_sinfo->lock);
3701
3702         return 0;
3703 }
3704
3705 /*
3706  * Called if we need to clear a data reservation for this inode.
3707  */
3708 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3709 {
3710         struct btrfs_root *root = BTRFS_I(inode)->root;
3711         struct btrfs_space_info *data_sinfo;
3712
3713         /* make sure bytes are sectorsize aligned */
3714         bytes = ALIGN(bytes, root->sectorsize);
3715
3716         data_sinfo = root->fs_info->data_sinfo;
3717         spin_lock(&data_sinfo->lock);
3718         WARN_ON(data_sinfo->bytes_may_use < bytes);
3719         data_sinfo->bytes_may_use -= bytes;
3720         trace_btrfs_space_reservation(root->fs_info, "space_info",
3721                                       data_sinfo->flags, bytes, 0);
3722         spin_unlock(&data_sinfo->lock);
3723 }
3724
3725 static void force_metadata_allocation(struct btrfs_fs_info *info)
3726 {
3727         struct list_head *head = &info->space_info;
3728         struct btrfs_space_info *found;
3729
3730         rcu_read_lock();
3731         list_for_each_entry_rcu(found, head, list) {
3732                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3733                         found->force_alloc = CHUNK_ALLOC_FORCE;
3734         }
3735         rcu_read_unlock();
3736 }
3737
3738 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3739 {
3740         return (global->size << 1);
3741 }
3742
3743 static int should_alloc_chunk(struct btrfs_root *root,
3744                               struct btrfs_space_info *sinfo, int force)
3745 {
3746         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3747         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3748         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3749         u64 thresh;
3750
3751         if (force == CHUNK_ALLOC_FORCE)
3752                 return 1;
3753
3754         /*
3755          * We need to take into account the global rsv because for all intents
3756          * and purposes it's used space.  Don't worry about locking the
3757          * global_rsv, it doesn't change except when the transaction commits.
3758          */
3759         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3760                 num_allocated += calc_global_rsv_need_space(global_rsv);
3761
3762         /*
3763          * in limited mode, we want to have some free space up to
3764          * about 1% of the FS size.
3765          */
3766         if (force == CHUNK_ALLOC_LIMITED) {
3767                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3768                 thresh = max_t(u64, 64 * 1024 * 1024,
3769                                div_factor_fine(thresh, 1));
3770
3771                 if (num_bytes - num_allocated < thresh)
3772                         return 1;
3773         }
3774
3775         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3776                 return 0;
3777         return 1;
3778 }
3779
3780 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3781 {
3782         u64 num_dev;
3783
3784         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3785                     BTRFS_BLOCK_GROUP_RAID0 |
3786                     BTRFS_BLOCK_GROUP_RAID5 |
3787                     BTRFS_BLOCK_GROUP_RAID6))
3788                 num_dev = root->fs_info->fs_devices->rw_devices;
3789         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3790                 num_dev = 2;
3791         else
3792                 num_dev = 1;    /* DUP or single */
3793
3794         /* metadata for updaing devices and chunk tree */
3795         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3796 }
3797
3798 static void check_system_chunk(struct btrfs_trans_handle *trans,
3799                                struct btrfs_root *root, u64 type)
3800 {
3801         struct btrfs_space_info *info;
3802         u64 left;
3803         u64 thresh;
3804
3805         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3806         spin_lock(&info->lock);
3807         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3808                 info->bytes_reserved - info->bytes_readonly;
3809         spin_unlock(&info->lock);
3810
3811         thresh = get_system_chunk_thresh(root, type);
3812         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3813                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
3814                         left, thresh, type);
3815                 dump_space_info(info, 0, 0);
3816         }
3817
3818         if (left < thresh) {
3819                 u64 flags;
3820
3821                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3822                 btrfs_alloc_chunk(trans, root, flags);
3823         }
3824 }
3825
3826 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3827                           struct btrfs_root *extent_root, u64 flags, int force)
3828 {
3829         struct btrfs_space_info *space_info;
3830         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3831         int wait_for_alloc = 0;
3832         int ret = 0;
3833
3834         /* Don't re-enter if we're already allocating a chunk */
3835         if (trans->allocating_chunk)
3836                 return -ENOSPC;
3837
3838         space_info = __find_space_info(extent_root->fs_info, flags);
3839         if (!space_info) {
3840                 ret = update_space_info(extent_root->fs_info, flags,
3841                                         0, 0, &space_info);
3842                 BUG_ON(ret); /* -ENOMEM */
3843         }
3844         BUG_ON(!space_info); /* Logic error */
3845
3846 again:
3847         spin_lock(&space_info->lock);
3848         if (force < space_info->force_alloc)
3849                 force = space_info->force_alloc;
3850         if (space_info->full) {
3851                 if (should_alloc_chunk(extent_root, space_info, force))
3852                         ret = -ENOSPC;
3853                 else
3854                         ret = 0;
3855                 spin_unlock(&space_info->lock);
3856                 return ret;
3857         }
3858
3859         if (!should_alloc_chunk(extent_root, space_info, force)) {
3860                 spin_unlock(&space_info->lock);
3861                 return 0;
3862         } else if (space_info->chunk_alloc) {
3863                 wait_for_alloc = 1;
3864         } else {
3865                 space_info->chunk_alloc = 1;
3866         }
3867
3868         spin_unlock(&space_info->lock);
3869
3870         mutex_lock(&fs_info->chunk_mutex);
3871
3872         /*
3873          * The chunk_mutex is held throughout the entirety of a chunk
3874          * allocation, so once we've acquired the chunk_mutex we know that the
3875          * other guy is done and we need to recheck and see if we should
3876          * allocate.
3877          */
3878         if (wait_for_alloc) {
3879                 mutex_unlock(&fs_info->chunk_mutex);
3880                 wait_for_alloc = 0;
3881                 goto again;
3882         }
3883
3884         trans->allocating_chunk = true;
3885
3886         /*
3887          * If we have mixed data/metadata chunks we want to make sure we keep
3888          * allocating mixed chunks instead of individual chunks.
3889          */
3890         if (btrfs_mixed_space_info(space_info))
3891                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3892
3893         /*
3894          * if we're doing a data chunk, go ahead and make sure that
3895          * we keep a reasonable number of metadata chunks allocated in the
3896          * FS as well.
3897          */
3898         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3899                 fs_info->data_chunk_allocations++;
3900                 if (!(fs_info->data_chunk_allocations %
3901                       fs_info->metadata_ratio))
3902                         force_metadata_allocation(fs_info);
3903         }
3904
3905         /*
3906          * Check if we have enough space in SYSTEM chunk because we may need
3907          * to update devices.
3908          */
3909         check_system_chunk(trans, extent_root, flags);
3910
3911         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3912         trans->allocating_chunk = false;
3913
3914         spin_lock(&space_info->lock);
3915         if (ret < 0 && ret != -ENOSPC)
3916                 goto out;
3917         if (ret)
3918                 space_info->full = 1;
3919         else
3920                 ret = 1;
3921
3922         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3923 out:
3924         space_info->chunk_alloc = 0;
3925         spin_unlock(&space_info->lock);
3926         mutex_unlock(&fs_info->chunk_mutex);
3927         return ret;
3928 }
3929
3930 static int can_overcommit(struct btrfs_root *root,
3931                           struct btrfs_space_info *space_info, u64 bytes,
3932                           enum btrfs_reserve_flush_enum flush)
3933 {
3934         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3935         u64 profile = btrfs_get_alloc_profile(root, 0);
3936         u64 space_size;
3937         u64 avail;
3938         u64 used;
3939
3940         used = space_info->bytes_used + space_info->bytes_reserved +
3941                 space_info->bytes_pinned + space_info->bytes_readonly;
3942
3943         /*
3944          * We only want to allow over committing if we have lots of actual space
3945          * free, but if we don't have enough space to handle the global reserve
3946          * space then we could end up having a real enospc problem when trying
3947          * to allocate a chunk or some other such important allocation.
3948          */
3949         spin_lock(&global_rsv->lock);
3950         space_size = calc_global_rsv_need_space(global_rsv);
3951         spin_unlock(&global_rsv->lock);
3952         if (used + space_size >= space_info->total_bytes)
3953                 return 0;
3954
3955         used += space_info->bytes_may_use;
3956
3957         spin_lock(&root->fs_info->free_chunk_lock);
3958         avail = root->fs_info->free_chunk_space;
3959         spin_unlock(&root->fs_info->free_chunk_lock);
3960
3961         /*
3962          * If we have dup, raid1 or raid10 then only half of the free
3963          * space is actually useable.  For raid56, the space info used
3964          * doesn't include the parity drive, so we don't have to
3965          * change the math
3966          */
3967         if (profile & (BTRFS_BLOCK_GROUP_DUP |
3968                        BTRFS_BLOCK_GROUP_RAID1 |
3969                        BTRFS_BLOCK_GROUP_RAID10))
3970                 avail >>= 1;
3971
3972         /*
3973          * If we aren't flushing all things, let us overcommit up to
3974          * 1/2th of the space. If we can flush, don't let us overcommit
3975          * too much, let it overcommit up to 1/8 of the space.
3976          */
3977         if (flush == BTRFS_RESERVE_FLUSH_ALL)
3978                 avail >>= 3;
3979         else
3980                 avail >>= 1;
3981
3982         if (used + bytes < space_info->total_bytes + avail)
3983                 return 1;
3984         return 0;
3985 }
3986
3987 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
3988                                          unsigned long nr_pages, int nr_items)
3989 {
3990         struct super_block *sb = root->fs_info->sb;
3991
3992         if (down_read_trylock(&sb->s_umount)) {
3993                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
3994                 up_read(&sb->s_umount);
3995         } else {
3996                 /*
3997                  * We needn't worry the filesystem going from r/w to r/o though
3998                  * we don't acquire ->s_umount mutex, because the filesystem
3999                  * should guarantee the delalloc inodes list be empty after
4000                  * the filesystem is readonly(all dirty pages are written to
4001                  * the disk).
4002                  */
4003                 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4004                 if (!current->journal_info)
4005                         btrfs_wait_ordered_roots(root->fs_info, nr_items);
4006         }
4007 }
4008
4009 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4010 {
4011         u64 bytes;
4012         int nr;
4013
4014         bytes = btrfs_calc_trans_metadata_size(root, 1);
4015         nr = (int)div64_u64(to_reclaim, bytes);
4016         if (!nr)
4017                 nr = 1;
4018         return nr;
4019 }
4020
4021 #define EXTENT_SIZE_PER_ITEM    (256 * 1024)
4022
4023 /*
4024  * shrink metadata reservation for delalloc
4025  */
4026 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4027                             bool wait_ordered)
4028 {
4029         struct btrfs_block_rsv *block_rsv;
4030         struct btrfs_space_info *space_info;
4031         struct btrfs_trans_handle *trans;
4032         u64 delalloc_bytes;
4033         u64 max_reclaim;
4034         long time_left;
4035         unsigned long nr_pages;
4036         int loops;
4037         int items;
4038         enum btrfs_reserve_flush_enum flush;
4039
4040         /* Calc the number of the pages we need flush for space reservation */
4041         items = calc_reclaim_items_nr(root, to_reclaim);
4042         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4043
4044         trans = (struct btrfs_trans_handle *)current->journal_info;
4045         block_rsv = &root->fs_info->delalloc_block_rsv;
4046         space_info = block_rsv->space_info;
4047
4048         delalloc_bytes = percpu_counter_sum_positive(
4049                                                 &root->fs_info->delalloc_bytes);
4050         if (delalloc_bytes == 0) {
4051                 if (trans)
4052                         return;
4053                 if (wait_ordered)
4054                         btrfs_wait_ordered_roots(root->fs_info, items);
4055                 return;
4056         }
4057
4058         loops = 0;
4059         while (delalloc_bytes && loops < 3) {
4060                 max_reclaim = min(delalloc_bytes, to_reclaim);
4061                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4062                 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4063                 /*
4064                  * We need to wait for the async pages to actually start before
4065                  * we do anything.
4066                  */
4067                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4068                 if (!max_reclaim)
4069                         goto skip_async;
4070
4071                 if (max_reclaim <= nr_pages)
4072                         max_reclaim = 0;
4073                 else
4074                         max_reclaim -= nr_pages;
4075
4076                 wait_event(root->fs_info->async_submit_wait,
4077                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4078                            (int)max_reclaim);
4079 skip_async:
4080                 if (!trans)
4081                         flush = BTRFS_RESERVE_FLUSH_ALL;
4082                 else
4083                         flush = BTRFS_RESERVE_NO_FLUSH;
4084                 spin_lock(&space_info->lock);
4085                 if (can_overcommit(root, space_info, orig, flush)) {
4086                         spin_unlock(&space_info->lock);
4087                         break;
4088                 }
4089                 spin_unlock(&space_info->lock);
4090
4091                 loops++;
4092                 if (wait_ordered && !trans) {
4093                         btrfs_wait_ordered_roots(root->fs_info, items);
4094                 } else {
4095                         time_left = schedule_timeout_killable(1);
4096                         if (time_left)
4097                                 break;
4098                 }
4099                 delalloc_bytes = percpu_counter_sum_positive(
4100                                                 &root->fs_info->delalloc_bytes);
4101         }
4102 }
4103
4104 /**
4105  * maybe_commit_transaction - possibly commit the transaction if its ok to
4106  * @root - the root we're allocating for
4107  * @bytes - the number of bytes we want to reserve
4108  * @force - force the commit
4109  *
4110  * This will check to make sure that committing the transaction will actually
4111  * get us somewhere and then commit the transaction if it does.  Otherwise it
4112  * will return -ENOSPC.
4113  */
4114 static int may_commit_transaction(struct btrfs_root *root,
4115                                   struct btrfs_space_info *space_info,
4116                                   u64 bytes, int force)
4117 {
4118         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4119         struct btrfs_trans_handle *trans;
4120
4121         trans = (struct btrfs_trans_handle *)current->journal_info;
4122         if (trans)
4123                 return -EAGAIN;
4124
4125         if (force)
4126                 goto commit;
4127
4128         /* See if there is enough pinned space to make this reservation */
4129         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4130                                    bytes) >= 0)
4131                 goto commit;
4132
4133         /*
4134          * See if there is some space in the delayed insertion reservation for
4135          * this reservation.
4136          */
4137         if (space_info != delayed_rsv->space_info)
4138                 return -ENOSPC;
4139
4140         spin_lock(&delayed_rsv->lock);
4141         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4142                                    bytes - delayed_rsv->size) >= 0) {
4143                 spin_unlock(&delayed_rsv->lock);
4144                 return -ENOSPC;
4145         }
4146         spin_unlock(&delayed_rsv->lock);
4147
4148 commit:
4149         trans = btrfs_join_transaction(root);
4150         if (IS_ERR(trans))
4151                 return -ENOSPC;
4152
4153         return btrfs_commit_transaction(trans, root);
4154 }
4155
4156 enum flush_state {
4157         FLUSH_DELAYED_ITEMS_NR  =       1,
4158         FLUSH_DELAYED_ITEMS     =       2,
4159         FLUSH_DELALLOC          =       3,
4160         FLUSH_DELALLOC_WAIT     =       4,
4161         ALLOC_CHUNK             =       5,
4162         COMMIT_TRANS            =       6,
4163 };
4164
4165 static int flush_space(struct btrfs_root *root,
4166                        struct btrfs_space_info *space_info, u64 num_bytes,
4167                        u64 orig_bytes, int state)
4168 {
4169         struct btrfs_trans_handle *trans;
4170         int nr;
4171         int ret = 0;
4172
4173         switch (state) {
4174         case FLUSH_DELAYED_ITEMS_NR:
4175         case FLUSH_DELAYED_ITEMS:
4176                 if (state == FLUSH_DELAYED_ITEMS_NR)
4177                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4178                 else
4179                         nr = -1;
4180
4181                 trans = btrfs_join_transaction(root);
4182                 if (IS_ERR(trans)) {
4183                         ret = PTR_ERR(trans);
4184                         break;
4185                 }
4186                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4187                 btrfs_end_transaction(trans, root);
4188                 break;
4189         case FLUSH_DELALLOC:
4190         case FLUSH_DELALLOC_WAIT:
4191                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4192                                 state == FLUSH_DELALLOC_WAIT);
4193                 break;
4194         case ALLOC_CHUNK:
4195                 trans = btrfs_join_transaction(root);
4196                 if (IS_ERR(trans)) {
4197                         ret = PTR_ERR(trans);
4198                         break;
4199                 }
4200                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4201                                      btrfs_get_alloc_profile(root, 0),
4202                                      CHUNK_ALLOC_NO_FORCE);
4203                 btrfs_end_transaction(trans, root);
4204                 if (ret == -ENOSPC)
4205                         ret = 0;
4206                 break;
4207         case COMMIT_TRANS:
4208                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4209                 break;
4210         default:
4211                 ret = -ENOSPC;
4212                 break;
4213         }
4214
4215         return ret;
4216 }
4217
4218 static inline u64
4219 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4220                                  struct btrfs_space_info *space_info)
4221 {
4222         u64 used;
4223         u64 expected;
4224         u64 to_reclaim;
4225
4226         to_reclaim = min_t(u64, num_online_cpus() * 1024 * 1024,
4227                                 16 * 1024 * 1024);
4228         spin_lock(&space_info->lock);
4229         if (can_overcommit(root, space_info, to_reclaim,
4230                            BTRFS_RESERVE_FLUSH_ALL)) {
4231                 to_reclaim = 0;
4232                 goto out;
4233         }
4234
4235         used = space_info->bytes_used + space_info->bytes_reserved +
4236                space_info->bytes_pinned + space_info->bytes_readonly +
4237                space_info->bytes_may_use;
4238         if (can_overcommit(root, space_info, 1024 * 1024,
4239                            BTRFS_RESERVE_FLUSH_ALL))
4240                 expected = div_factor_fine(space_info->total_bytes, 95);
4241         else
4242                 expected = div_factor_fine(space_info->total_bytes, 90);
4243
4244         if (used > expected)
4245                 to_reclaim = used - expected;
4246         else
4247                 to_reclaim = 0;
4248         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4249                                      space_info->bytes_reserved);
4250 out:
4251         spin_unlock(&space_info->lock);
4252
4253         return to_reclaim;
4254 }
4255
4256 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4257                                         struct btrfs_fs_info *fs_info, u64 used)
4258 {
4259         return (used >= div_factor_fine(space_info->total_bytes, 98) &&
4260                 !btrfs_fs_closing(fs_info) &&
4261                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4262 }
4263
4264 static int btrfs_need_do_async_reclaim(struct btrfs_space_info *space_info,
4265                                        struct btrfs_fs_info *fs_info,
4266                                        int flush_state)
4267 {
4268         u64 used;
4269
4270         spin_lock(&space_info->lock);
4271         /*
4272          * We run out of space and have not got any free space via flush_space,
4273          * so don't bother doing async reclaim.
4274          */
4275         if (flush_state > COMMIT_TRANS && space_info->full) {
4276                 spin_unlock(&space_info->lock);
4277                 return 0;
4278         }
4279
4280         used = space_info->bytes_used + space_info->bytes_reserved +
4281                space_info->bytes_pinned + space_info->bytes_readonly +
4282                space_info->bytes_may_use;
4283         if (need_do_async_reclaim(space_info, fs_info, used)) {
4284                 spin_unlock(&space_info->lock);
4285                 return 1;
4286         }
4287         spin_unlock(&space_info->lock);
4288
4289         return 0;
4290 }
4291
4292 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4293 {
4294         struct btrfs_fs_info *fs_info;
4295         struct btrfs_space_info *space_info;
4296         u64 to_reclaim;
4297         int flush_state;
4298
4299         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4300         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4301
4302         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4303                                                       space_info);
4304         if (!to_reclaim)
4305                 return;
4306
4307         flush_state = FLUSH_DELAYED_ITEMS_NR;
4308         do {
4309                 flush_space(fs_info->fs_root, space_info, to_reclaim,
4310                             to_reclaim, flush_state);
4311                 flush_state++;
4312                 if (!btrfs_need_do_async_reclaim(space_info, fs_info,
4313                                                  flush_state))
4314                         return;
4315         } while (flush_state <= COMMIT_TRANS);
4316
4317         if (btrfs_need_do_async_reclaim(space_info, fs_info, flush_state))
4318                 queue_work(system_unbound_wq, work);
4319 }
4320
4321 void btrfs_init_async_reclaim_work(struct work_struct *work)
4322 {
4323         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
4324 }
4325
4326 /**
4327  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4328  * @root - the root we're allocating for
4329  * @block_rsv - the block_rsv we're allocating for
4330  * @orig_bytes - the number of bytes we want
4331  * @flush - whether or not we can flush to make our reservation
4332  *
4333  * This will reserve orgi_bytes number of bytes from the space info associated
4334  * with the block_rsv.  If there is not enough space it will make an attempt to
4335  * flush out space to make room.  It will do this by flushing delalloc if
4336  * possible or committing the transaction.  If flush is 0 then no attempts to
4337  * regain reservations will be made and this will fail if there is not enough
4338  * space already.
4339  */
4340 static int reserve_metadata_bytes(struct btrfs_root *root,
4341                                   struct btrfs_block_rsv *block_rsv,
4342                                   u64 orig_bytes,
4343                                   enum btrfs_reserve_flush_enum flush)
4344 {
4345         struct btrfs_space_info *space_info = block_rsv->space_info;
4346         u64 used;
4347         u64 num_bytes = orig_bytes;
4348         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4349         int ret = 0;
4350         bool flushing = false;
4351
4352 again:
4353         ret = 0;
4354         spin_lock(&space_info->lock);
4355         /*
4356          * We only want to wait if somebody other than us is flushing and we
4357          * are actually allowed to flush all things.
4358          */
4359         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4360                space_info->flush) {
4361                 spin_unlock(&space_info->lock);
4362                 /*
4363                  * If we have a trans handle we can't wait because the flusher
4364                  * may have to commit the transaction, which would mean we would
4365                  * deadlock since we are waiting for the flusher to finish, but
4366                  * hold the current transaction open.
4367                  */
4368                 if (current->journal_info)
4369                         return -EAGAIN;
4370                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4371                 /* Must have been killed, return */
4372                 if (ret)
4373                         return -EINTR;
4374
4375                 spin_lock(&space_info->lock);
4376         }
4377
4378         ret = -ENOSPC;
4379         used = space_info->bytes_used + space_info->bytes_reserved +
4380                 space_info->bytes_pinned + space_info->bytes_readonly +
4381                 space_info->bytes_may_use;
4382
4383         /*
4384          * The idea here is that we've not already over-reserved the block group
4385          * then we can go ahead and save our reservation first and then start
4386          * flushing if we need to.  Otherwise if we've already overcommitted
4387          * lets start flushing stuff first and then come back and try to make
4388          * our reservation.
4389          */
4390         if (used <= space_info->total_bytes) {
4391                 if (used + orig_bytes <= space_info->total_bytes) {
4392                         space_info->bytes_may_use += orig_bytes;
4393                         trace_btrfs_space_reservation(root->fs_info,
4394                                 "space_info", space_info->flags, orig_bytes, 1);
4395                         ret = 0;
4396                 } else {
4397                         /*
4398                          * Ok set num_bytes to orig_bytes since we aren't
4399                          * overocmmitted, this way we only try and reclaim what
4400                          * we need.
4401                          */
4402                         num_bytes = orig_bytes;
4403                 }
4404         } else {
4405                 /*
4406                  * Ok we're over committed, set num_bytes to the overcommitted
4407                  * amount plus the amount of bytes that we need for this
4408                  * reservation.
4409                  */
4410                 num_bytes = used - space_info->total_bytes +
4411                         (orig_bytes * 2);
4412         }
4413
4414         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4415                 space_info->bytes_may_use += orig_bytes;
4416                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4417                                               space_info->flags, orig_bytes,
4418                                               1);
4419                 ret = 0;
4420         }
4421
4422         /*
4423          * Couldn't make our reservation, save our place so while we're trying
4424          * to reclaim space we can actually use it instead of somebody else
4425          * stealing it from us.
4426          *
4427          * We make the other tasks wait for the flush only when we can flush
4428          * all things.
4429          */
4430         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4431                 flushing = true;
4432                 space_info->flush = 1;
4433         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
4434                 used += orig_bytes;
4435                 /*
4436                  * We will do the space reservation dance during log replay,
4437                  * which means we won't have fs_info->fs_root set, so don't do
4438                  * the async reclaim as we will panic.
4439                  */
4440                 if (!root->fs_info->log_root_recovering &&
4441                     need_do_async_reclaim(space_info, root->fs_info, used) &&
4442                     !work_busy(&root->fs_info->async_reclaim_work))
4443                         queue_work(system_unbound_wq,
4444                                    &root->fs_info->async_reclaim_work);
4445         }
4446         spin_unlock(&space_info->lock);
4447
4448         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4449                 goto out;
4450
4451         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4452                           flush_state);
4453         flush_state++;
4454
4455         /*
4456          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4457          * would happen. So skip delalloc flush.
4458          */
4459         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4460             (flush_state == FLUSH_DELALLOC ||
4461              flush_state == FLUSH_DELALLOC_WAIT))
4462                 flush_state = ALLOC_CHUNK;
4463
4464         if (!ret)
4465                 goto again;
4466         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4467                  flush_state < COMMIT_TRANS)
4468                 goto again;
4469         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4470                  flush_state <= COMMIT_TRANS)
4471                 goto again;
4472
4473 out:
4474         if (ret == -ENOSPC &&
4475             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4476                 struct btrfs_block_rsv *global_rsv =
4477                         &root->fs_info->global_block_rsv;
4478
4479                 if (block_rsv != global_rsv &&
4480                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4481                         ret = 0;
4482         }
4483         if (ret == -ENOSPC)
4484                 trace_btrfs_space_reservation(root->fs_info,
4485                                               "space_info:enospc",
4486                                               space_info->flags, orig_bytes, 1);
4487         if (flushing) {
4488                 spin_lock(&space_info->lock);
4489                 space_info->flush = 0;
4490                 wake_up_all(&space_info->wait);
4491                 spin_unlock(&space_info->lock);
4492         }
4493         return ret;
4494 }
4495
4496 static struct btrfs_block_rsv *get_block_rsv(
4497                                         const struct btrfs_trans_handle *trans,
4498                                         const struct btrfs_root *root)
4499 {
4500         struct btrfs_block_rsv *block_rsv = NULL;
4501
4502         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
4503                 block_rsv = trans->block_rsv;
4504
4505         if (root == root->fs_info->csum_root && trans->adding_csums)
4506                 block_rsv = trans->block_rsv;
4507
4508         if (root == root->fs_info->uuid_root)
4509                 block_rsv = trans->block_rsv;
4510
4511         if (!block_rsv)
4512                 block_rsv = root->block_rsv;
4513
4514         if (!block_rsv)
4515                 block_rsv = &root->fs_info->empty_block_rsv;
4516
4517         return block_rsv;
4518 }
4519
4520 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4521                                u64 num_bytes)
4522 {
4523         int ret = -ENOSPC;
4524         spin_lock(&block_rsv->lock);
4525         if (block_rsv->reserved >= num_bytes) {
4526                 block_rsv->reserved -= num_bytes;
4527                 if (block_rsv->reserved < block_rsv->size)
4528                         block_rsv->full = 0;
4529                 ret = 0;
4530         }
4531         spin_unlock(&block_rsv->lock);
4532         return ret;
4533 }
4534
4535 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4536                                 u64 num_bytes, int update_size)
4537 {
4538         spin_lock(&block_rsv->lock);
4539         block_rsv->reserved += num_bytes;
4540         if (update_size)
4541                 block_rsv->size += num_bytes;
4542         else if (block_rsv->reserved >= block_rsv->size)
4543                 block_rsv->full = 1;
4544         spin_unlock(&block_rsv->lock);
4545 }
4546
4547 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4548                              struct btrfs_block_rsv *dest, u64 num_bytes,
4549                              int min_factor)
4550 {
4551         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4552         u64 min_bytes;
4553
4554         if (global_rsv->space_info != dest->space_info)
4555                 return -ENOSPC;
4556
4557         spin_lock(&global_rsv->lock);
4558         min_bytes = div_factor(global_rsv->size, min_factor);
4559         if (global_rsv->reserved < min_bytes + num_bytes) {
4560                 spin_unlock(&global_rsv->lock);
4561                 return -ENOSPC;
4562         }
4563         global_rsv->reserved -= num_bytes;
4564         if (global_rsv->reserved < global_rsv->size)
4565                 global_rsv->full = 0;
4566         spin_unlock(&global_rsv->lock);
4567
4568         block_rsv_add_bytes(dest, num_bytes, 1);
4569         return 0;
4570 }
4571
4572 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4573                                     struct btrfs_block_rsv *block_rsv,
4574                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4575 {
4576         struct btrfs_space_info *space_info = block_rsv->space_info;
4577
4578         spin_lock(&block_rsv->lock);
4579         if (num_bytes == (u64)-1)
4580                 num_bytes = block_rsv->size;
4581         block_rsv->size -= num_bytes;
4582         if (block_rsv->reserved >= block_rsv->size) {
4583                 num_bytes = block_rsv->reserved - block_rsv->size;
4584                 block_rsv->reserved = block_rsv->size;
4585                 block_rsv->full = 1;
4586         } else {
4587                 num_bytes = 0;
4588         }
4589         spin_unlock(&block_rsv->lock);
4590
4591         if (num_bytes > 0) {
4592                 if (dest) {
4593                         spin_lock(&dest->lock);
4594                         if (!dest->full) {
4595                                 u64 bytes_to_add;
4596
4597                                 bytes_to_add = dest->size - dest->reserved;
4598                                 bytes_to_add = min(num_bytes, bytes_to_add);
4599                                 dest->reserved += bytes_to_add;
4600                                 if (dest->reserved >= dest->size)
4601                                         dest->full = 1;
4602                                 num_bytes -= bytes_to_add;
4603                         }
4604                         spin_unlock(&dest->lock);
4605                 }
4606                 if (num_bytes) {
4607                         spin_lock(&space_info->lock);
4608                         space_info->bytes_may_use -= num_bytes;
4609                         trace_btrfs_space_reservation(fs_info, "space_info",
4610                                         space_info->flags, num_bytes, 0);
4611                         spin_unlock(&space_info->lock);
4612                 }
4613         }
4614 }
4615
4616 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4617                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4618 {
4619         int ret;
4620
4621         ret = block_rsv_use_bytes(src, num_bytes);
4622         if (ret)
4623                 return ret;
4624
4625         block_rsv_add_bytes(dst, num_bytes, 1);
4626         return 0;
4627 }
4628
4629 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4630 {
4631         memset(rsv, 0, sizeof(*rsv));
4632         spin_lock_init(&rsv->lock);
4633         rsv->type = type;
4634 }
4635
4636 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4637                                               unsigned short type)
4638 {
4639         struct btrfs_block_rsv *block_rsv;
4640         struct btrfs_fs_info *fs_info = root->fs_info;
4641
4642         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4643         if (!block_rsv)
4644                 return NULL;
4645
4646         btrfs_init_block_rsv(block_rsv, type);
4647         block_rsv->space_info = __find_space_info(fs_info,
4648                                                   BTRFS_BLOCK_GROUP_METADATA);
4649         return block_rsv;
4650 }
4651
4652 void btrfs_free_block_rsv(struct btrfs_root *root,
4653                           struct btrfs_block_rsv *rsv)
4654 {
4655         if (!rsv)
4656                 return;
4657         btrfs_block_rsv_release(root, rsv, (u64)-1);
4658         kfree(rsv);
4659 }
4660
4661 int btrfs_block_rsv_add(struct btrfs_root *root,
4662                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4663                         enum btrfs_reserve_flush_enum flush)
4664 {
4665         int ret;
4666
4667         if (num_bytes == 0)
4668                 return 0;
4669
4670         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4671         if (!ret) {
4672                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4673                 return 0;
4674         }
4675
4676         return ret;
4677 }
4678
4679 int btrfs_block_rsv_check(struct btrfs_root *root,
4680                           struct btrfs_block_rsv *block_rsv, int min_factor)
4681 {
4682         u64 num_bytes = 0;
4683         int ret = -ENOSPC;
4684
4685         if (!block_rsv)
4686                 return 0;
4687
4688         spin_lock(&block_rsv->lock);
4689         num_bytes = div_factor(block_rsv->size, min_factor);
4690         if (block_rsv->reserved >= num_bytes)
4691                 ret = 0;
4692         spin_unlock(&block_rsv->lock);
4693
4694         return ret;
4695 }
4696
4697 int btrfs_block_rsv_refill(struct btrfs_root *root,
4698                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4699                            enum btrfs_reserve_flush_enum flush)
4700 {
4701         u64 num_bytes = 0;
4702         int ret = -ENOSPC;
4703
4704         if (!block_rsv)
4705                 return 0;
4706
4707         spin_lock(&block_rsv->lock);
4708         num_bytes = min_reserved;
4709         if (block_rsv->reserved >= num_bytes)
4710                 ret = 0;
4711         else
4712                 num_bytes -= block_rsv->reserved;
4713         spin_unlock(&block_rsv->lock);
4714
4715         if (!ret)
4716                 return 0;
4717
4718         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4719         if (!ret) {
4720                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4721                 return 0;
4722         }
4723
4724         return ret;
4725 }
4726
4727 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4728                             struct btrfs_block_rsv *dst_rsv,
4729                             u64 num_bytes)
4730 {
4731         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4732 }
4733
4734 void btrfs_block_rsv_release(struct btrfs_root *root,
4735                              struct btrfs_block_rsv *block_rsv,
4736                              u64 num_bytes)
4737 {
4738         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4739         if (global_rsv == block_rsv ||
4740             block_rsv->space_info != global_rsv->space_info)
4741                 global_rsv = NULL;
4742         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4743                                 num_bytes);
4744 }
4745
4746 /*
4747  * helper to calculate size of global block reservation.
4748  * the desired value is sum of space used by extent tree,
4749  * checksum tree and root tree
4750  */
4751 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4752 {
4753         struct btrfs_space_info *sinfo;
4754         u64 num_bytes;
4755         u64 meta_used;
4756         u64 data_used;
4757         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4758
4759         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4760         spin_lock(&sinfo->lock);
4761         data_used = sinfo->bytes_used;
4762         spin_unlock(&sinfo->lock);
4763
4764         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4765         spin_lock(&sinfo->lock);
4766         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4767                 data_used = 0;
4768         meta_used = sinfo->bytes_used;
4769         spin_unlock(&sinfo->lock);
4770
4771         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4772                     csum_size * 2;
4773         num_bytes += div64_u64(data_used + meta_used, 50);
4774
4775         if (num_bytes * 3 > meta_used)
4776                 num_bytes = div64_u64(meta_used, 3);
4777
4778         return ALIGN(num_bytes, fs_info->extent_root->nodesize << 10);
4779 }
4780
4781 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4782 {
4783         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4784         struct btrfs_space_info *sinfo = block_rsv->space_info;
4785         u64 num_bytes;
4786
4787         num_bytes = calc_global_metadata_size(fs_info);
4788
4789         spin_lock(&sinfo->lock);
4790         spin_lock(&block_rsv->lock);
4791
4792         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
4793
4794         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4795                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4796                     sinfo->bytes_may_use;
4797
4798         if (sinfo->total_bytes > num_bytes) {
4799                 num_bytes = sinfo->total_bytes - num_bytes;
4800                 block_rsv->reserved += num_bytes;
4801                 sinfo->bytes_may_use += num_bytes;
4802                 trace_btrfs_space_reservation(fs_info, "space_info",
4803                                       sinfo->flags, num_bytes, 1);
4804         }
4805
4806         if (block_rsv->reserved >= block_rsv->size) {
4807                 num_bytes = block_rsv->reserved - block_rsv->size;
4808                 sinfo->bytes_may_use -= num_bytes;
4809                 trace_btrfs_space_reservation(fs_info, "space_info",
4810                                       sinfo->flags, num_bytes, 0);
4811                 block_rsv->reserved = block_rsv->size;
4812                 block_rsv->full = 1;
4813         }
4814
4815         spin_unlock(&block_rsv->lock);
4816         spin_unlock(&sinfo->lock);
4817 }
4818
4819 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4820 {
4821         struct btrfs_space_info *space_info;
4822
4823         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4824         fs_info->chunk_block_rsv.space_info = space_info;
4825
4826         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4827         fs_info->global_block_rsv.space_info = space_info;
4828         fs_info->delalloc_block_rsv.space_info = space_info;
4829         fs_info->trans_block_rsv.space_info = space_info;
4830         fs_info->empty_block_rsv.space_info = space_info;
4831         fs_info->delayed_block_rsv.space_info = space_info;
4832
4833         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4834         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4835         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4836         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4837         if (fs_info->quota_root)
4838                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
4839         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4840
4841         update_global_block_rsv(fs_info);
4842 }
4843
4844 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4845 {
4846         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4847                                 (u64)-1);
4848         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4849         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4850         WARN_ON(fs_info->trans_block_rsv.size > 0);
4851         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4852         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4853         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4854         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4855         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4856 }
4857
4858 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4859                                   struct btrfs_root *root)
4860 {
4861         if (!trans->block_rsv)
4862                 return;
4863
4864         if (!trans->bytes_reserved)
4865                 return;
4866
4867         trace_btrfs_space_reservation(root->fs_info, "transaction",
4868                                       trans->transid, trans->bytes_reserved, 0);
4869         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4870         trans->bytes_reserved = 0;
4871 }
4872
4873 /* Can only return 0 or -ENOSPC */
4874 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4875                                   struct inode *inode)
4876 {
4877         struct btrfs_root *root = BTRFS_I(inode)->root;
4878         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4879         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4880
4881         /*
4882          * We need to hold space in order to delete our orphan item once we've
4883          * added it, so this takes the reservation so we can release it later
4884          * when we are truly done with the orphan item.
4885          */
4886         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4887         trace_btrfs_space_reservation(root->fs_info, "orphan",
4888                                       btrfs_ino(inode), num_bytes, 1);
4889         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4890 }
4891
4892 void btrfs_orphan_release_metadata(struct inode *inode)
4893 {
4894         struct btrfs_root *root = BTRFS_I(inode)->root;
4895         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4896         trace_btrfs_space_reservation(root->fs_info, "orphan",
4897                                       btrfs_ino(inode), num_bytes, 0);
4898         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4899 }
4900
4901 /*
4902  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4903  * root: the root of the parent directory
4904  * rsv: block reservation
4905  * items: the number of items that we need do reservation
4906  * qgroup_reserved: used to return the reserved size in qgroup
4907  *
4908  * This function is used to reserve the space for snapshot/subvolume
4909  * creation and deletion. Those operations are different with the
4910  * common file/directory operations, they change two fs/file trees
4911  * and root tree, the number of items that the qgroup reserves is
4912  * different with the free space reservation. So we can not use
4913  * the space reseravtion mechanism in start_transaction().
4914  */
4915 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4916                                      struct btrfs_block_rsv *rsv,
4917                                      int items,
4918                                      u64 *qgroup_reserved,
4919                                      bool use_global_rsv)
4920 {
4921         u64 num_bytes;
4922         int ret;
4923         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4924
4925         if (root->fs_info->quota_enabled) {
4926                 /* One for parent inode, two for dir entries */
4927                 num_bytes = 3 * root->nodesize;
4928                 ret = btrfs_qgroup_reserve(root, num_bytes);
4929                 if (ret)
4930                         return ret;
4931         } else {
4932                 num_bytes = 0;
4933         }
4934
4935         *qgroup_reserved = num_bytes;
4936
4937         num_bytes = btrfs_calc_trans_metadata_size(root, items);
4938         rsv->space_info = __find_space_info(root->fs_info,
4939                                             BTRFS_BLOCK_GROUP_METADATA);
4940         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
4941                                   BTRFS_RESERVE_FLUSH_ALL);
4942
4943         if (ret == -ENOSPC && use_global_rsv)
4944                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
4945
4946         if (ret) {
4947                 if (*qgroup_reserved)
4948                         btrfs_qgroup_free(root, *qgroup_reserved);
4949         }
4950
4951         return ret;
4952 }
4953
4954 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
4955                                       struct btrfs_block_rsv *rsv,
4956                                       u64 qgroup_reserved)
4957 {
4958         btrfs_block_rsv_release(root, rsv, (u64)-1);
4959         if (qgroup_reserved)
4960                 btrfs_qgroup_free(root, qgroup_reserved);
4961 }
4962
4963 /**
4964  * drop_outstanding_extent - drop an outstanding extent
4965  * @inode: the inode we're dropping the extent for
4966  * @num_bytes: the number of bytes we're relaseing.
4967  *
4968  * This is called when we are freeing up an outstanding extent, either called
4969  * after an error or after an extent is written.  This will return the number of
4970  * reserved extents that need to be freed.  This must be called with
4971  * BTRFS_I(inode)->lock held.
4972  */
4973 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
4974 {
4975         unsigned drop_inode_space = 0;
4976         unsigned dropped_extents = 0;
4977         unsigned num_extents = 0;
4978
4979         num_extents = (unsigned)div64_u64(num_bytes +
4980                                           BTRFS_MAX_EXTENT_SIZE - 1,
4981                                           BTRFS_MAX_EXTENT_SIZE);
4982         ASSERT(num_extents);
4983         ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
4984         BTRFS_I(inode)->outstanding_extents -= num_extents;
4985
4986         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4987             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4988                                &BTRFS_I(inode)->runtime_flags))
4989                 drop_inode_space = 1;
4990
4991         /*
4992          * If we have more or the same amount of outsanding extents than we have
4993          * reserved then we need to leave the reserved extents count alone.
4994          */
4995         if (BTRFS_I(inode)->outstanding_extents >=
4996             BTRFS_I(inode)->reserved_extents)
4997                 return drop_inode_space;
4998
4999         dropped_extents = BTRFS_I(inode)->reserved_extents -
5000                 BTRFS_I(inode)->outstanding_extents;
5001         BTRFS_I(inode)->reserved_extents -= dropped_extents;
5002         return dropped_extents + drop_inode_space;
5003 }
5004
5005 /**
5006  * calc_csum_metadata_size - return the amount of metada space that must be
5007  *      reserved/free'd for the given bytes.
5008  * @inode: the inode we're manipulating
5009  * @num_bytes: the number of bytes in question
5010  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5011  *
5012  * This adjusts the number of csum_bytes in the inode and then returns the
5013  * correct amount of metadata that must either be reserved or freed.  We
5014  * calculate how many checksums we can fit into one leaf and then divide the
5015  * number of bytes that will need to be checksumed by this value to figure out
5016  * how many checksums will be required.  If we are adding bytes then the number
5017  * may go up and we will return the number of additional bytes that must be
5018  * reserved.  If it is going down we will return the number of bytes that must
5019  * be freed.
5020  *
5021  * This must be called with BTRFS_I(inode)->lock held.
5022  */
5023 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5024                                    int reserve)
5025 {
5026         struct btrfs_root *root = BTRFS_I(inode)->root;
5027         u64 csum_size;
5028         int num_csums_per_leaf;
5029         int num_csums;
5030         int old_csums;
5031
5032         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5033             BTRFS_I(inode)->csum_bytes == 0)
5034                 return 0;
5035
5036         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
5037         if (reserve)
5038                 BTRFS_I(inode)->csum_bytes += num_bytes;
5039         else
5040                 BTRFS_I(inode)->csum_bytes -= num_bytes;
5041         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
5042         num_csums_per_leaf = (int)div64_u64(csum_size,
5043                                             sizeof(struct btrfs_csum_item) +
5044                                             sizeof(struct btrfs_disk_key));
5045         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
5046         num_csums = num_csums + num_csums_per_leaf - 1;
5047         num_csums = num_csums / num_csums_per_leaf;
5048
5049         old_csums = old_csums + num_csums_per_leaf - 1;
5050         old_csums = old_csums / num_csums_per_leaf;
5051
5052         /* No change, no need to reserve more */
5053         if (old_csums == num_csums)
5054                 return 0;
5055
5056         if (reserve)
5057                 return btrfs_calc_trans_metadata_size(root,
5058                                                       num_csums - old_csums);
5059
5060         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5061 }
5062
5063 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5064 {
5065         struct btrfs_root *root = BTRFS_I(inode)->root;
5066         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5067         u64 to_reserve = 0;
5068         u64 csum_bytes;
5069         unsigned nr_extents = 0;
5070         int extra_reserve = 0;
5071         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5072         int ret = 0;
5073         bool delalloc_lock = true;
5074         u64 to_free = 0;
5075         unsigned dropped;
5076
5077         /* If we are a free space inode we need to not flush since we will be in
5078          * the middle of a transaction commit.  We also don't need the delalloc
5079          * mutex since we won't race with anybody.  We need this mostly to make
5080          * lockdep shut its filthy mouth.
5081          */
5082         if (btrfs_is_free_space_inode(inode)) {
5083                 flush = BTRFS_RESERVE_NO_FLUSH;
5084                 delalloc_lock = false;
5085         }
5086
5087         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5088             btrfs_transaction_in_commit(root->fs_info))
5089                 schedule_timeout(1);
5090
5091         if (delalloc_lock)
5092                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5093
5094         num_bytes = ALIGN(num_bytes, root->sectorsize);
5095
5096         spin_lock(&BTRFS_I(inode)->lock);
5097         BTRFS_I(inode)->outstanding_extents++;
5098
5099         if (BTRFS_I(inode)->outstanding_extents >
5100             BTRFS_I(inode)->reserved_extents)
5101                 nr_extents = BTRFS_I(inode)->outstanding_extents -
5102                         BTRFS_I(inode)->reserved_extents;
5103
5104         /*
5105          * Add an item to reserve for updating the inode when we complete the
5106          * delalloc io.
5107          */
5108         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5109                       &BTRFS_I(inode)->runtime_flags)) {
5110                 nr_extents++;
5111                 extra_reserve = 1;
5112         }
5113
5114         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5115         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5116         csum_bytes = BTRFS_I(inode)->csum_bytes;
5117         spin_unlock(&BTRFS_I(inode)->lock);
5118
5119         if (root->fs_info->quota_enabled) {
5120                 ret = btrfs_qgroup_reserve(root, num_bytes +
5121                                            nr_extents * root->nodesize);
5122                 if (ret)
5123                         goto out_fail;
5124         }
5125
5126         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5127         if (unlikely(ret)) {
5128                 if (root->fs_info->quota_enabled)
5129                         btrfs_qgroup_free(root, num_bytes +
5130                                                 nr_extents * root->nodesize);
5131                 goto out_fail;
5132         }
5133
5134         spin_lock(&BTRFS_I(inode)->lock);
5135         if (extra_reserve) {
5136                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5137                         &BTRFS_I(inode)->runtime_flags);
5138                 nr_extents--;
5139         }
5140         BTRFS_I(inode)->reserved_extents += nr_extents;
5141         spin_unlock(&BTRFS_I(inode)->lock);
5142
5143         if (delalloc_lock)
5144                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5145
5146         if (to_reserve)
5147                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5148                                               btrfs_ino(inode), to_reserve, 1);
5149         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5150
5151         return 0;
5152
5153 out_fail:
5154         spin_lock(&BTRFS_I(inode)->lock);
5155         dropped = drop_outstanding_extent(inode, num_bytes);
5156         /*
5157          * If the inodes csum_bytes is the same as the original
5158          * csum_bytes then we know we haven't raced with any free()ers
5159          * so we can just reduce our inodes csum bytes and carry on.
5160          */
5161         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5162                 calc_csum_metadata_size(inode, num_bytes, 0);
5163         } else {
5164                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5165                 u64 bytes;
5166
5167                 /*
5168                  * This is tricky, but first we need to figure out how much we
5169                  * free'd from any free-ers that occured during this
5170                  * reservation, so we reset ->csum_bytes to the csum_bytes
5171                  * before we dropped our lock, and then call the free for the
5172                  * number of bytes that were freed while we were trying our
5173                  * reservation.
5174                  */
5175                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5176                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5177                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5178
5179
5180                 /*
5181                  * Now we need to see how much we would have freed had we not
5182                  * been making this reservation and our ->csum_bytes were not
5183                  * artificially inflated.
5184                  */
5185                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5186                 bytes = csum_bytes - orig_csum_bytes;
5187                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5188
5189                 /*
5190                  * Now reset ->csum_bytes to what it should be.  If bytes is
5191                  * more than to_free then we would have free'd more space had we
5192                  * not had an artificially high ->csum_bytes, so we need to free
5193                  * the remainder.  If bytes is the same or less then we don't
5194                  * need to do anything, the other free-ers did the correct
5195                  * thing.
5196                  */
5197                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5198                 if (bytes > to_free)
5199                         to_free = bytes - to_free;
5200                 else
5201                         to_free = 0;
5202         }
5203         spin_unlock(&BTRFS_I(inode)->lock);
5204         if (dropped)
5205                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5206
5207         if (to_free) {
5208                 btrfs_block_rsv_release(root, block_rsv, to_free);
5209                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5210                                               btrfs_ino(inode), to_free, 0);
5211         }
5212         if (delalloc_lock)
5213                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5214         return ret;
5215 }
5216
5217 /**
5218  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5219  * @inode: the inode to release the reservation for
5220  * @num_bytes: the number of bytes we're releasing
5221  *
5222  * This will release the metadata reservation for an inode.  This can be called
5223  * once we complete IO for a given set of bytes to release their metadata
5224  * reservations.
5225  */
5226 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5227 {
5228         struct btrfs_root *root = BTRFS_I(inode)->root;
5229         u64 to_free = 0;
5230         unsigned dropped;
5231
5232         num_bytes = ALIGN(num_bytes, root->sectorsize);
5233         spin_lock(&BTRFS_I(inode)->lock);
5234         dropped = drop_outstanding_extent(inode, num_bytes);
5235
5236         if (num_bytes)
5237                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5238         spin_unlock(&BTRFS_I(inode)->lock);
5239         if (dropped > 0)
5240                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5241
5242         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5243                                       btrfs_ino(inode), to_free, 0);
5244         if (root->fs_info->quota_enabled) {
5245                 btrfs_qgroup_free(root, num_bytes +
5246                                         dropped * root->nodesize);
5247         }
5248
5249         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5250                                 to_free);
5251 }
5252
5253 /**
5254  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5255  * @inode: inode we're writing to
5256  * @num_bytes: the number of bytes we want to allocate
5257  *
5258  * This will do the following things
5259  *
5260  * o reserve space in the data space info for num_bytes
5261  * o reserve space in the metadata space info based on number of outstanding
5262  *   extents and how much csums will be needed
5263  * o add to the inodes ->delalloc_bytes
5264  * o add it to the fs_info's delalloc inodes list.
5265  *
5266  * This will return 0 for success and -ENOSPC if there is no space left.
5267  */
5268 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5269 {
5270         int ret;
5271
5272         ret = btrfs_check_data_free_space(inode, num_bytes);
5273         if (ret)
5274                 return ret;
5275
5276         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5277         if (ret) {
5278                 btrfs_free_reserved_data_space(inode, num_bytes);
5279                 return ret;
5280         }
5281
5282         return 0;
5283 }
5284
5285 /**
5286  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5287  * @inode: inode we're releasing space for
5288  * @num_bytes: the number of bytes we want to free up
5289  *
5290  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5291  * called in the case that we don't need the metadata AND data reservations
5292  * anymore.  So if there is an error or we insert an inline extent.
5293  *
5294  * This function will release the metadata space that was not used and will
5295  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5296  * list if there are no delalloc bytes left.
5297  */
5298 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5299 {
5300         btrfs_delalloc_release_metadata(inode, num_bytes);
5301         btrfs_free_reserved_data_space(inode, num_bytes);
5302 }
5303
5304 static int update_block_group(struct btrfs_trans_handle *trans,
5305                               struct btrfs_root *root, u64 bytenr,
5306                               u64 num_bytes, int alloc)
5307 {
5308         struct btrfs_block_group_cache *cache = NULL;
5309         struct btrfs_fs_info *info = root->fs_info;
5310         u64 total = num_bytes;
5311         u64 old_val;
5312         u64 byte_in_group;
5313         int factor;
5314
5315         /* block accounting for super block */
5316         spin_lock(&info->delalloc_root_lock);
5317         old_val = btrfs_super_bytes_used(info->super_copy);
5318         if (alloc)
5319                 old_val += num_bytes;
5320         else
5321                 old_val -= num_bytes;
5322         btrfs_set_super_bytes_used(info->super_copy, old_val);
5323         spin_unlock(&info->delalloc_root_lock);
5324
5325         while (total) {
5326                 cache = btrfs_lookup_block_group(info, bytenr);
5327                 if (!cache)
5328                         return -ENOENT;
5329                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5330                                     BTRFS_BLOCK_GROUP_RAID1 |
5331                                     BTRFS_BLOCK_GROUP_RAID10))
5332                         factor = 2;
5333                 else
5334                         factor = 1;
5335                 /*
5336                  * If this block group has free space cache written out, we
5337                  * need to make sure to load it if we are removing space.  This
5338                  * is because we need the unpinning stage to actually add the
5339                  * space back to the block group, otherwise we will leak space.
5340                  */
5341                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5342                         cache_block_group(cache, 1);
5343
5344                 spin_lock(&trans->transaction->dirty_bgs_lock);
5345                 if (list_empty(&cache->dirty_list)) {
5346                         list_add_tail(&cache->dirty_list,
5347                                       &trans->transaction->dirty_bgs);
5348                         btrfs_get_block_group(cache);
5349                 }
5350                 spin_unlock(&trans->transaction->dirty_bgs_lock);
5351
5352                 byte_in_group = bytenr - cache->key.objectid;
5353                 WARN_ON(byte_in_group > cache->key.offset);
5354
5355                 spin_lock(&cache->space_info->lock);
5356                 spin_lock(&cache->lock);
5357
5358                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5359                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5360                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5361
5362                 old_val = btrfs_block_group_used(&cache->item);
5363                 num_bytes = min(total, cache->key.offset - byte_in_group);
5364                 if (alloc) {
5365                         old_val += num_bytes;
5366                         btrfs_set_block_group_used(&cache->item, old_val);
5367                         cache->reserved -= num_bytes;
5368                         cache->space_info->bytes_reserved -= num_bytes;
5369                         cache->space_info->bytes_used += num_bytes;
5370                         cache->space_info->disk_used += num_bytes * factor;
5371                         spin_unlock(&cache->lock);
5372                         spin_unlock(&cache->space_info->lock);
5373                 } else {
5374                         old_val -= num_bytes;
5375                         btrfs_set_block_group_used(&cache->item, old_val);
5376                         cache->pinned += num_bytes;
5377                         cache->space_info->bytes_pinned += num_bytes;
5378                         cache->space_info->bytes_used -= num_bytes;
5379                         cache->space_info->disk_used -= num_bytes * factor;
5380                         spin_unlock(&cache->lock);
5381                         spin_unlock(&cache->space_info->lock);
5382
5383                         set_extent_dirty(info->pinned_extents,
5384                                          bytenr, bytenr + num_bytes - 1,
5385                                          GFP_NOFS | __GFP_NOFAIL);
5386                         /*
5387                          * No longer have used bytes in this block group, queue
5388                          * it for deletion.
5389                          */
5390                         if (old_val == 0) {
5391                                 spin_lock(&info->unused_bgs_lock);
5392                                 if (list_empty(&cache->bg_list)) {
5393                                         btrfs_get_block_group(cache);
5394                                         list_add_tail(&cache->bg_list,
5395                                                       &info->unused_bgs);
5396                                 }
5397                                 spin_unlock(&info->unused_bgs_lock);
5398                         }
5399                 }
5400                 btrfs_put_block_group(cache);
5401                 total -= num_bytes;
5402                 bytenr += num_bytes;
5403         }
5404         return 0;
5405 }
5406
5407 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5408 {
5409         struct btrfs_block_group_cache *cache;
5410         u64 bytenr;
5411
5412         spin_lock(&root->fs_info->block_group_cache_lock);
5413         bytenr = root->fs_info->first_logical_byte;
5414         spin_unlock(&root->fs_info->block_group_cache_lock);
5415
5416         if (bytenr < (u64)-1)
5417                 return bytenr;
5418
5419         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5420         if (!cache)
5421                 return 0;
5422
5423         bytenr = cache->key.objectid;
5424         btrfs_put_block_group(cache);
5425
5426         return bytenr;
5427 }
5428
5429 static int pin_down_extent(struct btrfs_root *root,
5430                            struct btrfs_block_group_cache *cache,
5431                            u64 bytenr, u64 num_bytes, int reserved)
5432 {
5433         spin_lock(&cache->space_info->lock);
5434         spin_lock(&cache->lock);
5435         cache->pinned += num_bytes;
5436         cache->space_info->bytes_pinned += num_bytes;
5437         if (reserved) {
5438                 cache->reserved -= num_bytes;
5439                 cache->space_info->bytes_reserved -= num_bytes;
5440         }
5441         spin_unlock(&cache->lock);
5442         spin_unlock(&cache->space_info->lock);
5443
5444         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5445                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5446         if (reserved)
5447                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
5448         return 0;
5449 }
5450
5451 /*
5452  * this function must be called within transaction
5453  */
5454 int btrfs_pin_extent(struct btrfs_root *root,
5455                      u64 bytenr, u64 num_bytes, int reserved)
5456 {
5457         struct btrfs_block_group_cache *cache;
5458
5459         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5460         BUG_ON(!cache); /* Logic error */
5461
5462         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5463
5464         btrfs_put_block_group(cache);
5465         return 0;
5466 }
5467
5468 /*
5469  * this function must be called within transaction
5470  */
5471 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5472                                     u64 bytenr, u64 num_bytes)
5473 {
5474         struct btrfs_block_group_cache *cache;
5475         int ret;
5476
5477         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5478         if (!cache)
5479                 return -EINVAL;
5480
5481         /*
5482          * pull in the free space cache (if any) so that our pin
5483          * removes the free space from the cache.  We have load_only set
5484          * to one because the slow code to read in the free extents does check
5485          * the pinned extents.
5486          */
5487         cache_block_group(cache, 1);
5488
5489         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5490
5491         /* remove us from the free space cache (if we're there at all) */
5492         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5493         btrfs_put_block_group(cache);
5494         return ret;
5495 }
5496
5497 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5498 {
5499         int ret;
5500         struct btrfs_block_group_cache *block_group;
5501         struct btrfs_caching_control *caching_ctl;
5502
5503         block_group = btrfs_lookup_block_group(root->fs_info, start);
5504         if (!block_group)
5505                 return -EINVAL;
5506
5507         cache_block_group(block_group, 0);
5508         caching_ctl = get_caching_control(block_group);
5509
5510         if (!caching_ctl) {
5511                 /* Logic error */
5512                 BUG_ON(!block_group_cache_done(block_group));
5513                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5514         } else {
5515                 mutex_lock(&caching_ctl->mutex);
5516
5517                 if (start >= caching_ctl->progress) {
5518                         ret = add_excluded_extent(root, start, num_bytes);
5519                 } else if (start + num_bytes <= caching_ctl->progress) {
5520                         ret = btrfs_remove_free_space(block_group,
5521                                                       start, num_bytes);
5522                 } else {
5523                         num_bytes = caching_ctl->progress - start;
5524                         ret = btrfs_remove_free_space(block_group,
5525                                                       start, num_bytes);
5526                         if (ret)
5527                                 goto out_lock;
5528
5529                         num_bytes = (start + num_bytes) -
5530                                 caching_ctl->progress;
5531                         start = caching_ctl->progress;
5532                         ret = add_excluded_extent(root, start, num_bytes);
5533                 }
5534 out_lock:
5535                 mutex_unlock(&caching_ctl->mutex);
5536                 put_caching_control(caching_ctl);
5537         }
5538         btrfs_put_block_group(block_group);
5539         return ret;
5540 }
5541
5542 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5543                                  struct extent_buffer *eb)
5544 {
5545         struct btrfs_file_extent_item *item;
5546         struct btrfs_key key;
5547         int found_type;
5548         int i;
5549
5550         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5551                 return 0;
5552
5553         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5554                 btrfs_item_key_to_cpu(eb, &key, i);
5555                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5556                         continue;
5557                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5558                 found_type = btrfs_file_extent_type(eb, item);
5559                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5560                         continue;
5561                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5562                         continue;
5563                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5564                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5565                 __exclude_logged_extent(log, key.objectid, key.offset);
5566         }
5567
5568         return 0;
5569 }
5570
5571 /**
5572  * btrfs_update_reserved_bytes - update the block_group and space info counters
5573  * @cache:      The cache we are manipulating
5574  * @num_bytes:  The number of bytes in question
5575  * @reserve:    One of the reservation enums
5576  * @delalloc:   The blocks are allocated for the delalloc write
5577  *
5578  * This is called by the allocator when it reserves space, or by somebody who is
5579  * freeing space that was never actually used on disk.  For example if you
5580  * reserve some space for a new leaf in transaction A and before transaction A
5581  * commits you free that leaf, you call this with reserve set to 0 in order to
5582  * clear the reservation.
5583  *
5584  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5585  * ENOSPC accounting.  For data we handle the reservation through clearing the
5586  * delalloc bits in the io_tree.  We have to do this since we could end up
5587  * allocating less disk space for the amount of data we have reserved in the
5588  * case of compression.
5589  *
5590  * If this is a reservation and the block group has become read only we cannot
5591  * make the reservation and return -EAGAIN, otherwise this function always
5592  * succeeds.
5593  */
5594 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5595                                        u64 num_bytes, int reserve, int delalloc)
5596 {
5597         struct btrfs_space_info *space_info = cache->space_info;
5598         int ret = 0;
5599
5600         spin_lock(&space_info->lock);
5601         spin_lock(&cache->lock);
5602         if (reserve != RESERVE_FREE) {
5603                 if (cache->ro) {
5604                         ret = -EAGAIN;
5605                 } else {
5606                         cache->reserved += num_bytes;
5607                         space_info->bytes_reserved += num_bytes;
5608                         if (reserve == RESERVE_ALLOC) {
5609                                 trace_btrfs_space_reservation(cache->fs_info,
5610                                                 "space_info", space_info->flags,
5611                                                 num_bytes, 0);
5612                                 space_info->bytes_may_use -= num_bytes;
5613                         }
5614
5615                         if (delalloc)
5616                                 cache->delalloc_bytes += num_bytes;
5617                 }
5618         } else {
5619                 if (cache->ro)
5620                         space_info->bytes_readonly += num_bytes;
5621                 cache->reserved -= num_bytes;
5622                 space_info->bytes_reserved -= num_bytes;
5623
5624                 if (delalloc)
5625                         cache->delalloc_bytes -= num_bytes;
5626         }
5627         spin_unlock(&cache->lock);
5628         spin_unlock(&space_info->lock);
5629         return ret;
5630 }
5631
5632 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5633                                 struct btrfs_root *root)
5634 {
5635         struct btrfs_fs_info *fs_info = root->fs_info;
5636         struct btrfs_caching_control *next;
5637         struct btrfs_caching_control *caching_ctl;
5638         struct btrfs_block_group_cache *cache;
5639
5640         down_write(&fs_info->commit_root_sem);
5641
5642         list_for_each_entry_safe(caching_ctl, next,
5643                                  &fs_info->caching_block_groups, list) {
5644                 cache = caching_ctl->block_group;
5645                 if (block_group_cache_done(cache)) {
5646                         cache->last_byte_to_unpin = (u64)-1;
5647                         list_del_init(&caching_ctl->list);
5648                         put_caching_control(caching_ctl);
5649                 } else {
5650                         cache->last_byte_to_unpin = caching_ctl->progress;
5651                 }
5652         }
5653
5654         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5655                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5656         else
5657                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5658
5659         up_write(&fs_info->commit_root_sem);
5660
5661         update_global_block_rsv(fs_info);
5662 }
5663
5664 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
5665                               const bool return_free_space)
5666 {
5667         struct btrfs_fs_info *fs_info = root->fs_info;
5668         struct btrfs_block_group_cache *cache = NULL;
5669         struct btrfs_space_info *space_info;
5670         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5671         u64 len;
5672         bool readonly;
5673
5674         while (start <= end) {
5675                 readonly = false;
5676                 if (!cache ||
5677                     start >= cache->key.objectid + cache->key.offset) {
5678                         if (cache)
5679                                 btrfs_put_block_group(cache);
5680                         cache = btrfs_lookup_block_group(fs_info, start);
5681                         BUG_ON(!cache); /* Logic error */
5682                 }
5683
5684                 len = cache->key.objectid + cache->key.offset - start;
5685                 len = min(len, end + 1 - start);
5686
5687                 if (start < cache->last_byte_to_unpin) {
5688                         len = min(len, cache->last_byte_to_unpin - start);
5689                         if (return_free_space)
5690                                 btrfs_add_free_space(cache, start, len);
5691                 }
5692
5693                 start += len;
5694                 space_info = cache->space_info;
5695
5696                 spin_lock(&space_info->lock);
5697                 spin_lock(&cache->lock);
5698                 cache->pinned -= len;
5699                 space_info->bytes_pinned -= len;
5700                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
5701                 if (cache->ro) {
5702                         space_info->bytes_readonly += len;
5703                         readonly = true;
5704                 }
5705                 spin_unlock(&cache->lock);
5706                 if (!readonly && global_rsv->space_info == space_info) {
5707                         spin_lock(&global_rsv->lock);
5708                         if (!global_rsv->full) {
5709                                 len = min(len, global_rsv->size -
5710                                           global_rsv->reserved);
5711                                 global_rsv->reserved += len;
5712                                 space_info->bytes_may_use += len;
5713                                 if (global_rsv->reserved >= global_rsv->size)
5714                                         global_rsv->full = 1;
5715                         }
5716                         spin_unlock(&global_rsv->lock);
5717                 }
5718                 spin_unlock(&space_info->lock);
5719         }
5720
5721         if (cache)
5722                 btrfs_put_block_group(cache);
5723         return 0;
5724 }
5725
5726 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5727                                struct btrfs_root *root)
5728 {
5729         struct btrfs_fs_info *fs_info = root->fs_info;
5730         struct extent_io_tree *unpin;
5731         u64 start;
5732         u64 end;
5733         int ret;
5734
5735         if (trans->aborted)
5736                 return 0;
5737
5738         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5739                 unpin = &fs_info->freed_extents[1];
5740         else
5741                 unpin = &fs_info->freed_extents[0];
5742
5743         while (1) {
5744                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
5745                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5746                                             EXTENT_DIRTY, NULL);
5747                 if (ret) {
5748                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
5749                         break;
5750                 }
5751
5752                 if (btrfs_test_opt(root, DISCARD))
5753                         ret = btrfs_discard_extent(root, start,
5754                                                    end + 1 - start, NULL);
5755
5756                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5757                 unpin_extent_range(root, start, end, true);
5758                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
5759                 cond_resched();
5760         }
5761
5762         return 0;
5763 }
5764
5765 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
5766                              u64 owner, u64 root_objectid)
5767 {
5768         struct btrfs_space_info *space_info;
5769         u64 flags;
5770
5771         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5772                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
5773                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
5774                 else
5775                         flags = BTRFS_BLOCK_GROUP_METADATA;
5776         } else {
5777                 flags = BTRFS_BLOCK_GROUP_DATA;
5778         }
5779
5780         space_info = __find_space_info(fs_info, flags);
5781         BUG_ON(!space_info); /* Logic bug */
5782         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
5783 }
5784
5785
5786 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5787                                 struct btrfs_root *root,
5788                                 u64 bytenr, u64 num_bytes, u64 parent,
5789                                 u64 root_objectid, u64 owner_objectid,
5790                                 u64 owner_offset, int refs_to_drop,
5791                                 struct btrfs_delayed_extent_op *extent_op,
5792                                 int no_quota)
5793 {
5794         struct btrfs_key key;
5795         struct btrfs_path *path;
5796         struct btrfs_fs_info *info = root->fs_info;
5797         struct btrfs_root *extent_root = info->extent_root;
5798         struct extent_buffer *leaf;
5799         struct btrfs_extent_item *ei;
5800         struct btrfs_extent_inline_ref *iref;
5801         int ret;
5802         int is_data;
5803         int extent_slot = 0;
5804         int found_extent = 0;
5805         int num_to_del = 1;
5806         u32 item_size;
5807         u64 refs;
5808         int last_ref = 0;
5809         enum btrfs_qgroup_operation_type type = BTRFS_QGROUP_OPER_SUB_EXCL;
5810         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
5811                                                  SKINNY_METADATA);
5812
5813         if (!info->quota_enabled || !is_fstree(root_objectid))
5814                 no_quota = 1;
5815
5816         path = btrfs_alloc_path();
5817         if (!path)
5818                 return -ENOMEM;
5819
5820         path->reada = 1;
5821         path->leave_spinning = 1;
5822
5823         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5824         BUG_ON(!is_data && refs_to_drop != 1);
5825
5826         if (is_data)
5827                 skinny_metadata = 0;
5828
5829         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5830                                     bytenr, num_bytes, parent,
5831                                     root_objectid, owner_objectid,
5832                                     owner_offset);
5833         if (ret == 0) {
5834                 extent_slot = path->slots[0];
5835                 while (extent_slot >= 0) {
5836                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5837                                               extent_slot);
5838                         if (key.objectid != bytenr)
5839                                 break;
5840                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5841                             key.offset == num_bytes) {
5842                                 found_extent = 1;
5843                                 break;
5844                         }
5845                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
5846                             key.offset == owner_objectid) {
5847                                 found_extent = 1;
5848                                 break;
5849                         }
5850                         if (path->slots[0] - extent_slot > 5)
5851                                 break;
5852                         extent_slot--;
5853                 }
5854 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5855                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5856                 if (found_extent && item_size < sizeof(*ei))
5857                         found_extent = 0;
5858 #endif
5859                 if (!found_extent) {
5860                         BUG_ON(iref);
5861                         ret = remove_extent_backref(trans, extent_root, path,
5862                                                     NULL, refs_to_drop,
5863                                                     is_data, &last_ref);
5864                         if (ret) {
5865                                 btrfs_abort_transaction(trans, extent_root, ret);
5866                                 goto out;
5867                         }
5868                         btrfs_release_path(path);
5869                         path->leave_spinning = 1;
5870
5871                         key.objectid = bytenr;
5872                         key.type = BTRFS_EXTENT_ITEM_KEY;
5873                         key.offset = num_bytes;
5874
5875                         if (!is_data && skinny_metadata) {
5876                                 key.type = BTRFS_METADATA_ITEM_KEY;
5877                                 key.offset = owner_objectid;
5878                         }
5879
5880                         ret = btrfs_search_slot(trans, extent_root,
5881                                                 &key, path, -1, 1);
5882                         if (ret > 0 && skinny_metadata && path->slots[0]) {
5883                                 /*
5884                                  * Couldn't find our skinny metadata item,
5885                                  * see if we have ye olde extent item.
5886                                  */
5887                                 path->slots[0]--;
5888                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
5889                                                       path->slots[0]);
5890                                 if (key.objectid == bytenr &&
5891                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
5892                                     key.offset == num_bytes)
5893                                         ret = 0;
5894                         }
5895
5896                         if (ret > 0 && skinny_metadata) {
5897                                 skinny_metadata = false;
5898                                 key.objectid = bytenr;
5899                                 key.type = BTRFS_EXTENT_ITEM_KEY;
5900                                 key.offset = num_bytes;
5901                                 btrfs_release_path(path);
5902                                 ret = btrfs_search_slot(trans, extent_root,
5903                                                         &key, path, -1, 1);
5904                         }
5905
5906                         if (ret) {
5907                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5908                                         ret, bytenr);
5909                                 if (ret > 0)
5910                                         btrfs_print_leaf(extent_root,
5911                                                          path->nodes[0]);
5912                         }
5913                         if (ret < 0) {
5914                                 btrfs_abort_transaction(trans, extent_root, ret);
5915                                 goto out;
5916                         }
5917                         extent_slot = path->slots[0];
5918                 }
5919         } else if (WARN_ON(ret == -ENOENT)) {
5920                 btrfs_print_leaf(extent_root, path->nodes[0]);
5921                 btrfs_err(info,
5922                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
5923                         bytenr, parent, root_objectid, owner_objectid,
5924                         owner_offset);
5925                 btrfs_abort_transaction(trans, extent_root, ret);
5926                 goto out;
5927         } else {
5928                 btrfs_abort_transaction(trans, extent_root, ret);
5929                 goto out;
5930         }
5931
5932         leaf = path->nodes[0];
5933         item_size = btrfs_item_size_nr(leaf, extent_slot);
5934 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5935         if (item_size < sizeof(*ei)) {
5936                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5937                 ret = convert_extent_item_v0(trans, extent_root, path,
5938                                              owner_objectid, 0);
5939                 if (ret < 0) {
5940                         btrfs_abort_transaction(trans, extent_root, ret);
5941                         goto out;
5942                 }
5943
5944                 btrfs_release_path(path);
5945                 path->leave_spinning = 1;
5946
5947                 key.objectid = bytenr;
5948                 key.type = BTRFS_EXTENT_ITEM_KEY;
5949                 key.offset = num_bytes;
5950
5951                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5952                                         -1, 1);
5953                 if (ret) {
5954                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5955                                 ret, bytenr);
5956                         btrfs_print_leaf(extent_root, path->nodes[0]);
5957                 }
5958                 if (ret < 0) {
5959                         btrfs_abort_transaction(trans, extent_root, ret);
5960                         goto out;
5961                 }
5962
5963                 extent_slot = path->slots[0];
5964                 leaf = path->nodes[0];
5965                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5966         }
5967 #endif
5968         BUG_ON(item_size < sizeof(*ei));
5969         ei = btrfs_item_ptr(leaf, extent_slot,
5970                             struct btrfs_extent_item);
5971         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
5972             key.type == BTRFS_EXTENT_ITEM_KEY) {
5973                 struct btrfs_tree_block_info *bi;
5974                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5975                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5976                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5977         }
5978
5979         refs = btrfs_extent_refs(leaf, ei);
5980         if (refs < refs_to_drop) {
5981                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
5982                           "for bytenr %Lu", refs_to_drop, refs, bytenr);
5983                 ret = -EINVAL;
5984                 btrfs_abort_transaction(trans, extent_root, ret);
5985                 goto out;
5986         }
5987         refs -= refs_to_drop;
5988
5989         if (refs > 0) {
5990                 type = BTRFS_QGROUP_OPER_SUB_SHARED;
5991                 if (extent_op)
5992                         __run_delayed_extent_op(extent_op, leaf, ei);
5993                 /*
5994                  * In the case of inline back ref, reference count will
5995                  * be updated by remove_extent_backref
5996                  */
5997                 if (iref) {
5998                         BUG_ON(!found_extent);
5999                 } else {
6000                         btrfs_set_extent_refs(leaf, ei, refs);
6001                         btrfs_mark_buffer_dirty(leaf);
6002                 }
6003                 if (found_extent) {
6004                         ret = remove_extent_backref(trans, extent_root, path,
6005                                                     iref, refs_to_drop,
6006                                                     is_data, &last_ref);
6007                         if (ret) {
6008                                 btrfs_abort_transaction(trans, extent_root, ret);
6009                                 goto out;
6010                         }
6011                 }
6012                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
6013                                  root_objectid);
6014         } else {
6015                 if (found_extent) {
6016                         BUG_ON(is_data && refs_to_drop !=
6017                                extent_data_ref_count(root, path, iref));
6018                         if (iref) {
6019                                 BUG_ON(path->slots[0] != extent_slot);
6020                         } else {
6021                                 BUG_ON(path->slots[0] != extent_slot + 1);
6022                                 path->slots[0] = extent_slot;
6023                                 num_to_del = 2;
6024                         }
6025                 }
6026
6027                 last_ref = 1;
6028                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6029                                       num_to_del);
6030                 if (ret) {
6031                         btrfs_abort_transaction(trans, extent_root, ret);
6032                         goto out;
6033                 }
6034                 btrfs_release_path(path);
6035
6036                 if (is_data) {
6037                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
6038                         if (ret) {
6039                                 btrfs_abort_transaction(trans, extent_root, ret);
6040                                 goto out;
6041                         }
6042                 }
6043
6044                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
6045                 if (ret) {
6046                         btrfs_abort_transaction(trans, extent_root, ret);
6047                         goto out;
6048                 }
6049         }
6050         btrfs_release_path(path);
6051
6052         /* Deal with the quota accounting */
6053         if (!ret && last_ref && !no_quota) {
6054                 int mod_seq = 0;
6055
6056                 if (owner_objectid >= BTRFS_FIRST_FREE_OBJECTID &&
6057                     type == BTRFS_QGROUP_OPER_SUB_SHARED)
6058                         mod_seq = 1;
6059
6060                 ret = btrfs_qgroup_record_ref(trans, info, root_objectid,
6061                                               bytenr, num_bytes, type,
6062                                               mod_seq);
6063         }
6064 out:
6065         btrfs_free_path(path);
6066         return ret;
6067 }
6068
6069 /*
6070  * when we free an block, it is possible (and likely) that we free the last
6071  * delayed ref for that extent as well.  This searches the delayed ref tree for
6072  * a given extent, and if there are no other delayed refs to be processed, it
6073  * removes it from the tree.
6074  */
6075 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6076                                       struct btrfs_root *root, u64 bytenr)
6077 {
6078         struct btrfs_delayed_ref_head *head;
6079         struct btrfs_delayed_ref_root *delayed_refs;
6080         int ret = 0;
6081
6082         delayed_refs = &trans->transaction->delayed_refs;
6083         spin_lock(&delayed_refs->lock);
6084         head = btrfs_find_delayed_ref_head(trans, bytenr);
6085         if (!head)
6086                 goto out_delayed_unlock;
6087
6088         spin_lock(&head->lock);
6089         if (rb_first(&head->ref_root))
6090                 goto out;
6091
6092         if (head->extent_op) {
6093                 if (!head->must_insert_reserved)
6094                         goto out;
6095                 btrfs_free_delayed_extent_op(head->extent_op);
6096                 head->extent_op = NULL;
6097         }
6098
6099         /*
6100          * waiting for the lock here would deadlock.  If someone else has it
6101          * locked they are already in the process of dropping it anyway
6102          */
6103         if (!mutex_trylock(&head->mutex))
6104                 goto out;
6105
6106         /*
6107          * at this point we have a head with no other entries.  Go
6108          * ahead and process it.
6109          */
6110         head->node.in_tree = 0;
6111         rb_erase(&head->href_node, &delayed_refs->href_root);
6112
6113         atomic_dec(&delayed_refs->num_entries);
6114
6115         /*
6116          * we don't take a ref on the node because we're removing it from the
6117          * tree, so we just steal the ref the tree was holding.
6118          */
6119         delayed_refs->num_heads--;
6120         if (head->processing == 0)
6121                 delayed_refs->num_heads_ready--;
6122         head->processing = 0;
6123         spin_unlock(&head->lock);
6124         spin_unlock(&delayed_refs->lock);
6125
6126         BUG_ON(head->extent_op);
6127         if (head->must_insert_reserved)
6128                 ret = 1;
6129
6130         mutex_unlock(&head->mutex);
6131         btrfs_put_delayed_ref(&head->node);
6132         return ret;
6133 out:
6134         spin_unlock(&head->lock);
6135
6136 out_delayed_unlock:
6137         spin_unlock(&delayed_refs->lock);
6138         return 0;
6139 }
6140
6141 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6142                            struct btrfs_root *root,
6143                            struct extent_buffer *buf,
6144                            u64 parent, int last_ref)
6145 {
6146         int pin = 1;
6147         int ret;
6148
6149         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6150                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6151                                         buf->start, buf->len,
6152                                         parent, root->root_key.objectid,
6153                                         btrfs_header_level(buf),
6154                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
6155                 BUG_ON(ret); /* -ENOMEM */
6156         }
6157
6158         if (!last_ref)
6159                 return;
6160
6161         if (btrfs_header_generation(buf) == trans->transid) {
6162                 struct btrfs_block_group_cache *cache;
6163
6164                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6165                         ret = check_ref_cleanup(trans, root, buf->start);
6166                         if (!ret)
6167                                 goto out;
6168                 }
6169
6170                 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6171
6172                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6173                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6174                         btrfs_put_block_group(cache);
6175                         goto out;
6176                 }
6177
6178                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6179
6180                 btrfs_add_free_space(cache, buf->start, buf->len);
6181                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
6182                 btrfs_put_block_group(cache);
6183                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6184                 pin = 0;
6185         }
6186 out:
6187         if (pin)
6188                 add_pinned_bytes(root->fs_info, buf->len,
6189                                  btrfs_header_level(buf),
6190                                  root->root_key.objectid);
6191
6192         /*
6193          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6194          * anymore.
6195          */
6196         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6197 }
6198
6199 /* Can return -ENOMEM */
6200 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6201                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6202                       u64 owner, u64 offset, int no_quota)
6203 {
6204         int ret;
6205         struct btrfs_fs_info *fs_info = root->fs_info;
6206
6207         if (btrfs_test_is_dummy_root(root))
6208                 return 0;
6209
6210         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6211
6212         /*
6213          * tree log blocks never actually go into the extent allocation
6214          * tree, just update pinning info and exit early.
6215          */
6216         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6217                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6218                 /* unlocks the pinned mutex */
6219                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6220                 ret = 0;
6221         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6222                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6223                                         num_bytes,
6224                                         parent, root_objectid, (int)owner,
6225                                         BTRFS_DROP_DELAYED_REF, NULL, no_quota);
6226         } else {
6227                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6228                                                 num_bytes,
6229                                                 parent, root_objectid, owner,
6230                                                 offset, BTRFS_DROP_DELAYED_REF,
6231                                                 NULL, no_quota);
6232         }
6233         return ret;
6234 }
6235
6236 /*
6237  * when we wait for progress in the block group caching, its because
6238  * our allocation attempt failed at least once.  So, we must sleep
6239  * and let some progress happen before we try again.
6240  *
6241  * This function will sleep at least once waiting for new free space to
6242  * show up, and then it will check the block group free space numbers
6243  * for our min num_bytes.  Another option is to have it go ahead
6244  * and look in the rbtree for a free extent of a given size, but this
6245  * is a good start.
6246  *
6247  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6248  * any of the information in this block group.
6249  */
6250 static noinline void
6251 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6252                                 u64 num_bytes)
6253 {
6254         struct btrfs_caching_control *caching_ctl;
6255
6256         caching_ctl = get_caching_control(cache);
6257         if (!caching_ctl)
6258                 return;
6259
6260         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6261                    (cache->free_space_ctl->free_space >= num_bytes));
6262
6263         put_caching_control(caching_ctl);
6264 }
6265
6266 static noinline int
6267 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6268 {
6269         struct btrfs_caching_control *caching_ctl;
6270         int ret = 0;
6271
6272         caching_ctl = get_caching_control(cache);
6273         if (!caching_ctl)
6274                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6275
6276         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6277         if (cache->cached == BTRFS_CACHE_ERROR)
6278                 ret = -EIO;
6279         put_caching_control(caching_ctl);
6280         return ret;
6281 }
6282
6283 int __get_raid_index(u64 flags)
6284 {
6285         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6286                 return BTRFS_RAID_RAID10;
6287         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6288                 return BTRFS_RAID_RAID1;
6289         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6290                 return BTRFS_RAID_DUP;
6291         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6292                 return BTRFS_RAID_RAID0;
6293         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6294                 return BTRFS_RAID_RAID5;
6295         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6296                 return BTRFS_RAID_RAID6;
6297
6298         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6299 }
6300
6301 int get_block_group_index(struct btrfs_block_group_cache *cache)
6302 {
6303         return __get_raid_index(cache->flags);
6304 }
6305
6306 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
6307         [BTRFS_RAID_RAID10]     = "raid10",
6308         [BTRFS_RAID_RAID1]      = "raid1",
6309         [BTRFS_RAID_DUP]        = "dup",
6310         [BTRFS_RAID_RAID0]      = "raid0",
6311         [BTRFS_RAID_SINGLE]     = "single",
6312         [BTRFS_RAID_RAID5]      = "raid5",
6313         [BTRFS_RAID_RAID6]      = "raid6",
6314 };
6315
6316 static const char *get_raid_name(enum btrfs_raid_types type)
6317 {
6318         if (type >= BTRFS_NR_RAID_TYPES)
6319                 return NULL;
6320
6321         return btrfs_raid_type_names[type];
6322 }
6323
6324 enum btrfs_loop_type {
6325         LOOP_CACHING_NOWAIT = 0,
6326         LOOP_CACHING_WAIT = 1,
6327         LOOP_ALLOC_CHUNK = 2,
6328         LOOP_NO_EMPTY_SIZE = 3,
6329 };
6330
6331 static inline void
6332 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
6333                        int delalloc)
6334 {
6335         if (delalloc)
6336                 down_read(&cache->data_rwsem);
6337 }
6338
6339 static inline void
6340 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
6341                        int delalloc)
6342 {
6343         btrfs_get_block_group(cache);
6344         if (delalloc)
6345                 down_read(&cache->data_rwsem);
6346 }
6347
6348 static struct btrfs_block_group_cache *
6349 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
6350                    struct btrfs_free_cluster *cluster,
6351                    int delalloc)
6352 {
6353         struct btrfs_block_group_cache *used_bg;
6354         bool locked = false;
6355 again:
6356         spin_lock(&cluster->refill_lock);
6357         if (locked) {
6358                 if (used_bg == cluster->block_group)
6359                         return used_bg;
6360
6361                 up_read(&used_bg->data_rwsem);
6362                 btrfs_put_block_group(used_bg);
6363         }
6364
6365         used_bg = cluster->block_group;
6366         if (!used_bg)
6367                 return NULL;
6368
6369         if (used_bg == block_group)
6370                 return used_bg;
6371
6372         btrfs_get_block_group(used_bg);
6373
6374         if (!delalloc)
6375                 return used_bg;
6376
6377         if (down_read_trylock(&used_bg->data_rwsem))
6378                 return used_bg;
6379
6380         spin_unlock(&cluster->refill_lock);
6381         down_read(&used_bg->data_rwsem);
6382         locked = true;
6383         goto again;
6384 }
6385
6386 static inline void
6387 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
6388                          int delalloc)
6389 {
6390         if (delalloc)
6391                 up_read(&cache->data_rwsem);
6392         btrfs_put_block_group(cache);
6393 }
6394
6395 /*
6396  * walks the btree of allocated extents and find a hole of a given size.
6397  * The key ins is changed to record the hole:
6398  * ins->objectid == start position
6399  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6400  * ins->offset == the size of the hole.
6401  * Any available blocks before search_start are skipped.
6402  *
6403  * If there is no suitable free space, we will record the max size of
6404  * the free space extent currently.
6405  */
6406 static noinline int find_free_extent(struct btrfs_root *orig_root,
6407                                      u64 num_bytes, u64 empty_size,
6408                                      u64 hint_byte, struct btrfs_key *ins,
6409                                      u64 flags, int delalloc)
6410 {
6411         int ret = 0;
6412         struct btrfs_root *root = orig_root->fs_info->extent_root;
6413         struct btrfs_free_cluster *last_ptr = NULL;
6414         struct btrfs_block_group_cache *block_group = NULL;
6415         u64 search_start = 0;
6416         u64 max_extent_size = 0;
6417         int empty_cluster = 2 * 1024 * 1024;
6418         struct btrfs_space_info *space_info;
6419         int loop = 0;
6420         int index = __get_raid_index(flags);
6421         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6422                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6423         bool failed_cluster_refill = false;
6424         bool failed_alloc = false;
6425         bool use_cluster = true;
6426         bool have_caching_bg = false;
6427
6428         WARN_ON(num_bytes < root->sectorsize);
6429         ins->type = BTRFS_EXTENT_ITEM_KEY;
6430         ins->objectid = 0;
6431         ins->offset = 0;
6432
6433         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6434
6435         space_info = __find_space_info(root->fs_info, flags);
6436         if (!space_info) {
6437                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6438                 return -ENOSPC;
6439         }
6440
6441         /*
6442          * If the space info is for both data and metadata it means we have a
6443          * small filesystem and we can't use the clustering stuff.
6444          */
6445         if (btrfs_mixed_space_info(space_info))
6446                 use_cluster = false;
6447
6448         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6449                 last_ptr = &root->fs_info->meta_alloc_cluster;
6450                 if (!btrfs_test_opt(root, SSD))
6451                         empty_cluster = 64 * 1024;
6452         }
6453
6454         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6455             btrfs_test_opt(root, SSD)) {
6456                 last_ptr = &root->fs_info->data_alloc_cluster;
6457         }
6458
6459         if (last_ptr) {
6460                 spin_lock(&last_ptr->lock);
6461                 if (last_ptr->block_group)
6462                         hint_byte = last_ptr->window_start;
6463                 spin_unlock(&last_ptr->lock);
6464         }
6465
6466         search_start = max(search_start, first_logical_byte(root, 0));
6467         search_start = max(search_start, hint_byte);
6468
6469         if (!last_ptr)
6470                 empty_cluster = 0;
6471
6472         if (search_start == hint_byte) {
6473                 block_group = btrfs_lookup_block_group(root->fs_info,
6474                                                        search_start);
6475                 /*
6476                  * we don't want to use the block group if it doesn't match our
6477                  * allocation bits, or if its not cached.
6478                  *
6479                  * However if we are re-searching with an ideal block group
6480                  * picked out then we don't care that the block group is cached.
6481                  */
6482                 if (block_group && block_group_bits(block_group, flags) &&
6483                     block_group->cached != BTRFS_CACHE_NO) {
6484                         down_read(&space_info->groups_sem);
6485                         if (list_empty(&block_group->list) ||
6486                             block_group->ro) {
6487                                 /*
6488                                  * someone is removing this block group,
6489                                  * we can't jump into the have_block_group
6490                                  * target because our list pointers are not
6491                                  * valid
6492                                  */
6493                                 btrfs_put_block_group(block_group);
6494                                 up_read(&space_info->groups_sem);
6495                         } else {
6496                                 index = get_block_group_index(block_group);
6497                                 btrfs_lock_block_group(block_group, delalloc);
6498                                 goto have_block_group;
6499                         }
6500                 } else if (block_group) {
6501                         btrfs_put_block_group(block_group);
6502                 }
6503         }
6504 search:
6505         have_caching_bg = false;
6506         down_read(&space_info->groups_sem);
6507         list_for_each_entry(block_group, &space_info->block_groups[index],
6508                             list) {
6509                 u64 offset;
6510                 int cached;
6511
6512                 btrfs_grab_block_group(block_group, delalloc);
6513                 search_start = block_group->key.objectid;
6514
6515                 /*
6516                  * this can happen if we end up cycling through all the
6517                  * raid types, but we want to make sure we only allocate
6518                  * for the proper type.
6519                  */
6520                 if (!block_group_bits(block_group, flags)) {
6521                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6522                                 BTRFS_BLOCK_GROUP_RAID1 |
6523                                 BTRFS_BLOCK_GROUP_RAID5 |
6524                                 BTRFS_BLOCK_GROUP_RAID6 |
6525                                 BTRFS_BLOCK_GROUP_RAID10;
6526
6527                         /*
6528                          * if they asked for extra copies and this block group
6529                          * doesn't provide them, bail.  This does allow us to
6530                          * fill raid0 from raid1.
6531                          */
6532                         if ((flags & extra) && !(block_group->flags & extra))
6533                                 goto loop;
6534                 }
6535
6536 have_block_group:
6537                 cached = block_group_cache_done(block_group);
6538                 if (unlikely(!cached)) {
6539                         ret = cache_block_group(block_group, 0);
6540                         BUG_ON(ret < 0);
6541                         ret = 0;
6542                 }
6543
6544                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
6545                         goto loop;
6546                 if (unlikely(block_group->ro))
6547                         goto loop;
6548
6549                 /*
6550                  * Ok we want to try and use the cluster allocator, so
6551                  * lets look there
6552                  */
6553                 if (last_ptr) {
6554                         struct btrfs_block_group_cache *used_block_group;
6555                         unsigned long aligned_cluster;
6556                         /*
6557                          * the refill lock keeps out other
6558                          * people trying to start a new cluster
6559                          */
6560                         used_block_group = btrfs_lock_cluster(block_group,
6561                                                               last_ptr,
6562                                                               delalloc);
6563                         if (!used_block_group)
6564                                 goto refill_cluster;
6565
6566                         if (used_block_group != block_group &&
6567                             (used_block_group->ro ||
6568                              !block_group_bits(used_block_group, flags)))
6569                                 goto release_cluster;
6570
6571                         offset = btrfs_alloc_from_cluster(used_block_group,
6572                                                 last_ptr,
6573                                                 num_bytes,
6574                                                 used_block_group->key.objectid,
6575                                                 &max_extent_size);
6576                         if (offset) {
6577                                 /* we have a block, we're done */
6578                                 spin_unlock(&last_ptr->refill_lock);
6579                                 trace_btrfs_reserve_extent_cluster(root,
6580                                                 used_block_group,
6581                                                 search_start, num_bytes);
6582                                 if (used_block_group != block_group) {
6583                                         btrfs_release_block_group(block_group,
6584                                                                   delalloc);
6585                                         block_group = used_block_group;
6586                                 }
6587                                 goto checks;
6588                         }
6589
6590                         WARN_ON(last_ptr->block_group != used_block_group);
6591 release_cluster:
6592                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6593                          * set up a new clusters, so lets just skip it
6594                          * and let the allocator find whatever block
6595                          * it can find.  If we reach this point, we
6596                          * will have tried the cluster allocator
6597                          * plenty of times and not have found
6598                          * anything, so we are likely way too
6599                          * fragmented for the clustering stuff to find
6600                          * anything.
6601                          *
6602                          * However, if the cluster is taken from the
6603                          * current block group, release the cluster
6604                          * first, so that we stand a better chance of
6605                          * succeeding in the unclustered
6606                          * allocation.  */
6607                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6608                             used_block_group != block_group) {
6609                                 spin_unlock(&last_ptr->refill_lock);
6610                                 btrfs_release_block_group(used_block_group,
6611                                                           delalloc);
6612                                 goto unclustered_alloc;
6613                         }
6614
6615                         /*
6616                          * this cluster didn't work out, free it and
6617                          * start over
6618                          */
6619                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6620
6621                         if (used_block_group != block_group)
6622                                 btrfs_release_block_group(used_block_group,
6623                                                           delalloc);
6624 refill_cluster:
6625                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6626                                 spin_unlock(&last_ptr->refill_lock);
6627                                 goto unclustered_alloc;
6628                         }
6629
6630                         aligned_cluster = max_t(unsigned long,
6631                                                 empty_cluster + empty_size,
6632                                               block_group->full_stripe_len);
6633
6634                         /* allocate a cluster in this block group */
6635                         ret = btrfs_find_space_cluster(root, block_group,
6636                                                        last_ptr, search_start,
6637                                                        num_bytes,
6638                                                        aligned_cluster);
6639                         if (ret == 0) {
6640                                 /*
6641                                  * now pull our allocation out of this
6642                                  * cluster
6643                                  */
6644                                 offset = btrfs_alloc_from_cluster(block_group,
6645                                                         last_ptr,
6646                                                         num_bytes,
6647                                                         search_start,
6648                                                         &max_extent_size);
6649                                 if (offset) {
6650                                         /* we found one, proceed */
6651                                         spin_unlock(&last_ptr->refill_lock);
6652                                         trace_btrfs_reserve_extent_cluster(root,
6653                                                 block_group, search_start,
6654                                                 num_bytes);
6655                                         goto checks;
6656                                 }
6657                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6658                                    && !failed_cluster_refill) {
6659                                 spin_unlock(&last_ptr->refill_lock);
6660
6661                                 failed_cluster_refill = true;
6662                                 wait_block_group_cache_progress(block_group,
6663                                        num_bytes + empty_cluster + empty_size);
6664                                 goto have_block_group;
6665                         }
6666
6667                         /*
6668                          * at this point we either didn't find a cluster
6669                          * or we weren't able to allocate a block from our
6670                          * cluster.  Free the cluster we've been trying
6671                          * to use, and go to the next block group
6672                          */
6673                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6674                         spin_unlock(&last_ptr->refill_lock);
6675                         goto loop;
6676                 }
6677
6678 unclustered_alloc:
6679                 spin_lock(&block_group->free_space_ctl->tree_lock);
6680                 if (cached &&
6681                     block_group->free_space_ctl->free_space <
6682                     num_bytes + empty_cluster + empty_size) {
6683                         if (block_group->free_space_ctl->free_space >
6684                             max_extent_size)
6685                                 max_extent_size =
6686                                         block_group->free_space_ctl->free_space;
6687                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6688                         goto loop;
6689                 }
6690                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6691
6692                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6693                                                     num_bytes, empty_size,
6694                                                     &max_extent_size);
6695                 /*
6696                  * If we didn't find a chunk, and we haven't failed on this
6697                  * block group before, and this block group is in the middle of
6698                  * caching and we are ok with waiting, then go ahead and wait
6699                  * for progress to be made, and set failed_alloc to true.
6700                  *
6701                  * If failed_alloc is true then we've already waited on this
6702                  * block group once and should move on to the next block group.
6703                  */
6704                 if (!offset && !failed_alloc && !cached &&
6705                     loop > LOOP_CACHING_NOWAIT) {
6706                         wait_block_group_cache_progress(block_group,
6707                                                 num_bytes + empty_size);
6708                         failed_alloc = true;
6709                         goto have_block_group;
6710                 } else if (!offset) {
6711                         if (!cached)
6712                                 have_caching_bg = true;
6713                         goto loop;
6714                 }
6715 checks:
6716                 search_start = ALIGN(offset, root->stripesize);
6717
6718                 /* move on to the next group */
6719                 if (search_start + num_bytes >
6720                     block_group->key.objectid + block_group->key.offset) {
6721                         btrfs_add_free_space(block_group, offset, num_bytes);
6722                         goto loop;
6723                 }
6724
6725                 if (offset < search_start)
6726                         btrfs_add_free_space(block_group, offset,
6727                                              search_start - offset);
6728                 BUG_ON(offset > search_start);
6729
6730                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
6731                                                   alloc_type, delalloc);
6732                 if (ret == -EAGAIN) {
6733                         btrfs_add_free_space(block_group, offset, num_bytes);
6734                         goto loop;
6735                 }
6736
6737                 /* we are all good, lets return */
6738                 ins->objectid = search_start;
6739                 ins->offset = num_bytes;
6740
6741                 trace_btrfs_reserve_extent(orig_root, block_group,
6742                                            search_start, num_bytes);
6743                 btrfs_release_block_group(block_group, delalloc);
6744                 break;
6745 loop:
6746                 failed_cluster_refill = false;
6747                 failed_alloc = false;
6748                 BUG_ON(index != get_block_group_index(block_group));
6749                 btrfs_release_block_group(block_group, delalloc);
6750         }
6751         up_read(&space_info->groups_sem);
6752
6753         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6754                 goto search;
6755
6756         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6757                 goto search;
6758
6759         /*
6760          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6761          *                      caching kthreads as we move along
6762          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6763          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6764          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6765          *                      again
6766          */
6767         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6768                 index = 0;
6769                 loop++;
6770                 if (loop == LOOP_ALLOC_CHUNK) {
6771                         struct btrfs_trans_handle *trans;
6772                         int exist = 0;
6773
6774                         trans = current->journal_info;
6775                         if (trans)
6776                                 exist = 1;
6777                         else
6778                                 trans = btrfs_join_transaction(root);
6779
6780                         if (IS_ERR(trans)) {
6781                                 ret = PTR_ERR(trans);
6782                                 goto out;
6783                         }
6784
6785                         ret = do_chunk_alloc(trans, root, flags,
6786                                              CHUNK_ALLOC_FORCE);
6787                         /*
6788                          * Do not bail out on ENOSPC since we
6789                          * can do more things.
6790                          */
6791                         if (ret < 0 && ret != -ENOSPC)
6792                                 btrfs_abort_transaction(trans,
6793                                                         root, ret);
6794                         else
6795                                 ret = 0;
6796                         if (!exist)
6797                                 btrfs_end_transaction(trans, root);
6798                         if (ret)
6799                                 goto out;
6800                 }
6801
6802                 if (loop == LOOP_NO_EMPTY_SIZE) {
6803                         empty_size = 0;
6804                         empty_cluster = 0;
6805                 }
6806
6807                 goto search;
6808         } else if (!ins->objectid) {
6809                 ret = -ENOSPC;
6810         } else if (ins->objectid) {
6811                 ret = 0;
6812         }
6813 out:
6814         if (ret == -ENOSPC)
6815                 ins->offset = max_extent_size;
6816         return ret;
6817 }
6818
6819 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6820                             int dump_block_groups)
6821 {
6822         struct btrfs_block_group_cache *cache;
6823         int index = 0;
6824
6825         spin_lock(&info->lock);
6826         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
6827                info->flags,
6828                info->total_bytes - info->bytes_used - info->bytes_pinned -
6829                info->bytes_reserved - info->bytes_readonly,
6830                (info->full) ? "" : "not ");
6831         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
6832                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6833                info->total_bytes, info->bytes_used, info->bytes_pinned,
6834                info->bytes_reserved, info->bytes_may_use,
6835                info->bytes_readonly);
6836         spin_unlock(&info->lock);
6837
6838         if (!dump_block_groups)
6839                 return;
6840
6841         down_read(&info->groups_sem);
6842 again:
6843         list_for_each_entry(cache, &info->block_groups[index], list) {
6844                 spin_lock(&cache->lock);
6845                 printk(KERN_INFO "BTRFS: "
6846                            "block group %llu has %llu bytes, "
6847                            "%llu used %llu pinned %llu reserved %s\n",
6848                        cache->key.objectid, cache->key.offset,
6849                        btrfs_block_group_used(&cache->item), cache->pinned,
6850                        cache->reserved, cache->ro ? "[readonly]" : "");
6851                 btrfs_dump_free_space(cache, bytes);
6852                 spin_unlock(&cache->lock);
6853         }
6854         if (++index < BTRFS_NR_RAID_TYPES)
6855                 goto again;
6856         up_read(&info->groups_sem);
6857 }
6858
6859 int btrfs_reserve_extent(struct btrfs_root *root,
6860                          u64 num_bytes, u64 min_alloc_size,
6861                          u64 empty_size, u64 hint_byte,
6862                          struct btrfs_key *ins, int is_data, int delalloc)
6863 {
6864         bool final_tried = false;
6865         u64 flags;
6866         int ret;
6867
6868         flags = btrfs_get_alloc_profile(root, is_data);
6869 again:
6870         WARN_ON(num_bytes < root->sectorsize);
6871         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
6872                                flags, delalloc);
6873
6874         if (ret == -ENOSPC) {
6875                 if (!final_tried && ins->offset) {
6876                         num_bytes = min(num_bytes >> 1, ins->offset);
6877                         num_bytes = round_down(num_bytes, root->sectorsize);
6878                         num_bytes = max(num_bytes, min_alloc_size);
6879                         if (num_bytes == min_alloc_size)
6880                                 final_tried = true;
6881                         goto again;
6882                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6883                         struct btrfs_space_info *sinfo;
6884
6885                         sinfo = __find_space_info(root->fs_info, flags);
6886                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
6887                                 flags, num_bytes);
6888                         if (sinfo)
6889                                 dump_space_info(sinfo, num_bytes, 1);
6890                 }
6891         }
6892
6893         return ret;
6894 }
6895
6896 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6897                                         u64 start, u64 len,
6898                                         int pin, int delalloc)
6899 {
6900         struct btrfs_block_group_cache *cache;
6901         int ret = 0;
6902
6903         cache = btrfs_lookup_block_group(root->fs_info, start);
6904         if (!cache) {
6905                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
6906                         start);
6907                 return -ENOSPC;
6908         }
6909
6910         if (btrfs_test_opt(root, DISCARD))
6911                 ret = btrfs_discard_extent(root, start, len, NULL);
6912
6913         if (pin)
6914                 pin_down_extent(root, cache, start, len, 1);
6915         else {
6916                 btrfs_add_free_space(cache, start, len);
6917                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
6918         }
6919         btrfs_put_block_group(cache);
6920
6921         trace_btrfs_reserved_extent_free(root, start, len);
6922
6923         return ret;
6924 }
6925
6926 int btrfs_free_reserved_extent(struct btrfs_root *root,
6927                                u64 start, u64 len, int delalloc)
6928 {
6929         return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
6930 }
6931
6932 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6933                                        u64 start, u64 len)
6934 {
6935         return __btrfs_free_reserved_extent(root, start, len, 1, 0);
6936 }
6937
6938 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6939                                       struct btrfs_root *root,
6940                                       u64 parent, u64 root_objectid,
6941                                       u64 flags, u64 owner, u64 offset,
6942                                       struct btrfs_key *ins, int ref_mod)
6943 {
6944         int ret;
6945         struct btrfs_fs_info *fs_info = root->fs_info;
6946         struct btrfs_extent_item *extent_item;
6947         struct btrfs_extent_inline_ref *iref;
6948         struct btrfs_path *path;
6949         struct extent_buffer *leaf;
6950         int type;
6951         u32 size;
6952
6953         if (parent > 0)
6954                 type = BTRFS_SHARED_DATA_REF_KEY;
6955         else
6956                 type = BTRFS_EXTENT_DATA_REF_KEY;
6957
6958         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6959
6960         path = btrfs_alloc_path();
6961         if (!path)
6962                 return -ENOMEM;
6963
6964         path->leave_spinning = 1;
6965         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6966                                       ins, size);
6967         if (ret) {
6968                 btrfs_free_path(path);
6969                 return ret;
6970         }
6971
6972         leaf = path->nodes[0];
6973         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6974                                      struct btrfs_extent_item);
6975         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6976         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6977         btrfs_set_extent_flags(leaf, extent_item,
6978                                flags | BTRFS_EXTENT_FLAG_DATA);
6979
6980         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6981         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6982         if (parent > 0) {
6983                 struct btrfs_shared_data_ref *ref;
6984                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6985                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6986                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6987         } else {
6988                 struct btrfs_extent_data_ref *ref;
6989                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6990                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6991                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6992                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6993                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6994         }
6995
6996         btrfs_mark_buffer_dirty(path->nodes[0]);
6997         btrfs_free_path(path);
6998
6999         /* Always set parent to 0 here since its exclusive anyway. */
7000         ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
7001                                       ins->objectid, ins->offset,
7002                                       BTRFS_QGROUP_OPER_ADD_EXCL, 0);
7003         if (ret)
7004                 return ret;
7005
7006         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
7007         if (ret) { /* -ENOENT, logic error */
7008                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7009                         ins->objectid, ins->offset);
7010                 BUG();
7011         }
7012         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
7013         return ret;
7014 }
7015
7016 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7017                                      struct btrfs_root *root,
7018                                      u64 parent, u64 root_objectid,
7019                                      u64 flags, struct btrfs_disk_key *key,
7020                                      int level, struct btrfs_key *ins,
7021                                      int no_quota)
7022 {
7023         int ret;
7024         struct btrfs_fs_info *fs_info = root->fs_info;
7025         struct btrfs_extent_item *extent_item;
7026         struct btrfs_tree_block_info *block_info;
7027         struct btrfs_extent_inline_ref *iref;
7028         struct btrfs_path *path;
7029         struct extent_buffer *leaf;
7030         u32 size = sizeof(*extent_item) + sizeof(*iref);
7031         u64 num_bytes = ins->offset;
7032         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7033                                                  SKINNY_METADATA);
7034
7035         if (!skinny_metadata)
7036                 size += sizeof(*block_info);
7037
7038         path = btrfs_alloc_path();
7039         if (!path) {
7040                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7041                                                    root->nodesize);
7042                 return -ENOMEM;
7043         }
7044
7045         path->leave_spinning = 1;
7046         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7047                                       ins, size);
7048         if (ret) {
7049                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7050                                                    root->nodesize);
7051                 btrfs_free_path(path);
7052                 return ret;
7053         }
7054
7055         leaf = path->nodes[0];
7056         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7057                                      struct btrfs_extent_item);
7058         btrfs_set_extent_refs(leaf, extent_item, 1);
7059         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7060         btrfs_set_extent_flags(leaf, extent_item,
7061                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
7062
7063         if (skinny_metadata) {
7064                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7065                 num_bytes = root->nodesize;
7066         } else {
7067                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
7068                 btrfs_set_tree_block_key(leaf, block_info, key);
7069                 btrfs_set_tree_block_level(leaf, block_info, level);
7070                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
7071         }
7072
7073         if (parent > 0) {
7074                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
7075                 btrfs_set_extent_inline_ref_type(leaf, iref,
7076                                                  BTRFS_SHARED_BLOCK_REF_KEY);
7077                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7078         } else {
7079                 btrfs_set_extent_inline_ref_type(leaf, iref,
7080                                                  BTRFS_TREE_BLOCK_REF_KEY);
7081                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
7082         }
7083
7084         btrfs_mark_buffer_dirty(leaf);
7085         btrfs_free_path(path);
7086
7087         if (!no_quota) {
7088                 ret = btrfs_qgroup_record_ref(trans, fs_info, root_objectid,
7089                                               ins->objectid, num_bytes,
7090                                               BTRFS_QGROUP_OPER_ADD_EXCL, 0);
7091                 if (ret)
7092                         return ret;
7093         }
7094
7095         ret = update_block_group(trans, root, ins->objectid, root->nodesize,
7096                                  1);
7097         if (ret) { /* -ENOENT, logic error */
7098                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7099                         ins->objectid, ins->offset);
7100                 BUG();
7101         }
7102
7103         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
7104         return ret;
7105 }
7106
7107 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7108                                      struct btrfs_root *root,
7109                                      u64 root_objectid, u64 owner,
7110                                      u64 offset, struct btrfs_key *ins)
7111 {
7112         int ret;
7113
7114         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
7115
7116         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
7117                                          ins->offset, 0,
7118                                          root_objectid, owner, offset,
7119                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
7120         return ret;
7121 }
7122
7123 /*
7124  * this is used by the tree logging recovery code.  It records that
7125  * an extent has been allocated and makes sure to clear the free
7126  * space cache bits as well
7127  */
7128 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
7129                                    struct btrfs_root *root,
7130                                    u64 root_objectid, u64 owner, u64 offset,
7131                                    struct btrfs_key *ins)
7132 {
7133         int ret;
7134         struct btrfs_block_group_cache *block_group;
7135
7136         /*
7137          * Mixed block groups will exclude before processing the log so we only
7138          * need to do the exlude dance if this fs isn't mixed.
7139          */
7140         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
7141                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
7142                 if (ret)
7143                         return ret;
7144         }
7145
7146         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
7147         if (!block_group)
7148                 return -EINVAL;
7149
7150         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
7151                                           RESERVE_ALLOC_NO_ACCOUNT, 0);
7152         BUG_ON(ret); /* logic error */
7153         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
7154                                          0, owner, offset, ins, 1);
7155         btrfs_put_block_group(block_group);
7156         return ret;
7157 }
7158
7159 static struct extent_buffer *
7160 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7161                       u64 bytenr, int level)
7162 {
7163         struct extent_buffer *buf;
7164
7165         buf = btrfs_find_create_tree_block(root, bytenr);
7166         if (!buf)
7167                 return ERR_PTR(-ENOMEM);
7168         btrfs_set_header_generation(buf, trans->transid);
7169         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
7170         btrfs_tree_lock(buf);
7171         clean_tree_block(trans, root, buf);
7172         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
7173
7174         btrfs_set_lock_blocking(buf);
7175         btrfs_set_buffer_uptodate(buf);
7176
7177         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
7178                 buf->log_index = root->log_transid % 2;
7179                 /*
7180                  * we allow two log transactions at a time, use different
7181                  * EXENT bit to differentiate dirty pages.
7182                  */
7183                 if (buf->log_index == 0)
7184                         set_extent_dirty(&root->dirty_log_pages, buf->start,
7185                                         buf->start + buf->len - 1, GFP_NOFS);
7186                 else
7187                         set_extent_new(&root->dirty_log_pages, buf->start,
7188                                         buf->start + buf->len - 1, GFP_NOFS);
7189         } else {
7190                 buf->log_index = -1;
7191                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
7192                          buf->start + buf->len - 1, GFP_NOFS);
7193         }
7194         trans->blocks_used++;
7195         /* this returns a buffer locked for blocking */
7196         return buf;
7197 }
7198
7199 static struct btrfs_block_rsv *
7200 use_block_rsv(struct btrfs_trans_handle *trans,
7201               struct btrfs_root *root, u32 blocksize)
7202 {
7203         struct btrfs_block_rsv *block_rsv;
7204         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
7205         int ret;
7206         bool global_updated = false;
7207
7208         block_rsv = get_block_rsv(trans, root);
7209
7210         if (unlikely(block_rsv->size == 0))
7211                 goto try_reserve;
7212 again:
7213         ret = block_rsv_use_bytes(block_rsv, blocksize);
7214         if (!ret)
7215                 return block_rsv;
7216
7217         if (block_rsv->failfast)
7218                 return ERR_PTR(ret);
7219
7220         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
7221                 global_updated = true;
7222                 update_global_block_rsv(root->fs_info);
7223                 goto again;
7224         }
7225
7226         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7227                 static DEFINE_RATELIMIT_STATE(_rs,
7228                                 DEFAULT_RATELIMIT_INTERVAL * 10,
7229                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
7230                 if (__ratelimit(&_rs))
7231                         WARN(1, KERN_DEBUG
7232                                 "BTRFS: block rsv returned %d\n", ret);
7233         }
7234 try_reserve:
7235         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
7236                                      BTRFS_RESERVE_NO_FLUSH);
7237         if (!ret)
7238                 return block_rsv;
7239         /*
7240          * If we couldn't reserve metadata bytes try and use some from
7241          * the global reserve if its space type is the same as the global
7242          * reservation.
7243          */
7244         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
7245             block_rsv->space_info == global_rsv->space_info) {
7246                 ret = block_rsv_use_bytes(global_rsv, blocksize);
7247                 if (!ret)
7248                         return global_rsv;
7249         }
7250         return ERR_PTR(ret);
7251 }
7252
7253 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
7254                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
7255 {
7256         block_rsv_add_bytes(block_rsv, blocksize, 0);
7257         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
7258 }
7259
7260 /*
7261  * finds a free extent and does all the dirty work required for allocation
7262  * returns the key for the extent through ins, and a tree buffer for
7263  * the first block of the extent through buf.
7264  *
7265  * returns the tree buffer or NULL.
7266  */
7267 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
7268                                         struct btrfs_root *root,
7269                                         u64 parent, u64 root_objectid,
7270                                         struct btrfs_disk_key *key, int level,
7271                                         u64 hint, u64 empty_size)
7272 {
7273         struct btrfs_key ins;
7274         struct btrfs_block_rsv *block_rsv;
7275         struct extent_buffer *buf;
7276         u64 flags = 0;
7277         int ret;
7278         u32 blocksize = root->nodesize;
7279         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7280                                                  SKINNY_METADATA);
7281
7282         if (btrfs_test_is_dummy_root(root)) {
7283                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
7284                                             level);
7285                 if (!IS_ERR(buf))
7286                         root->alloc_bytenr += blocksize;
7287                 return buf;
7288         }
7289
7290         block_rsv = use_block_rsv(trans, root, blocksize);
7291         if (IS_ERR(block_rsv))
7292                 return ERR_CAST(block_rsv);
7293
7294         ret = btrfs_reserve_extent(root, blocksize, blocksize,
7295                                    empty_size, hint, &ins, 0, 0);
7296         if (ret) {
7297                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
7298                 return ERR_PTR(ret);
7299         }
7300
7301         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
7302         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
7303
7304         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
7305                 if (parent == 0)
7306                         parent = ins.objectid;
7307                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
7308         } else
7309                 BUG_ON(parent > 0);
7310
7311         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
7312                 struct btrfs_delayed_extent_op *extent_op;
7313                 extent_op = btrfs_alloc_delayed_extent_op();
7314                 BUG_ON(!extent_op); /* -ENOMEM */
7315                 if (key)
7316                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
7317                 else
7318                         memset(&extent_op->key, 0, sizeof(extent_op->key));
7319                 extent_op->flags_to_set = flags;
7320                 if (skinny_metadata)
7321                         extent_op->update_key = 0;
7322                 else
7323                         extent_op->update_key = 1;
7324                 extent_op->update_flags = 1;
7325                 extent_op->is_data = 0;
7326                 extent_op->level = level;
7327
7328                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7329                                         ins.objectid,
7330                                         ins.offset, parent, root_objectid,
7331                                         level, BTRFS_ADD_DELAYED_EXTENT,
7332                                         extent_op, 0);
7333                 BUG_ON(ret); /* -ENOMEM */
7334         }
7335         return buf;
7336 }
7337
7338 struct walk_control {
7339         u64 refs[BTRFS_MAX_LEVEL];
7340         u64 flags[BTRFS_MAX_LEVEL];
7341         struct btrfs_key update_progress;
7342         int stage;
7343         int level;
7344         int shared_level;
7345         int update_ref;
7346         int keep_locks;
7347         int reada_slot;
7348         int reada_count;
7349         int for_reloc;
7350 };
7351
7352 #define DROP_REFERENCE  1
7353 #define UPDATE_BACKREF  2
7354
7355 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7356                                      struct btrfs_root *root,
7357                                      struct walk_control *wc,
7358                                      struct btrfs_path *path)
7359 {
7360         u64 bytenr;
7361         u64 generation;
7362         u64 refs;
7363         u64 flags;
7364         u32 nritems;
7365         u32 blocksize;
7366         struct btrfs_key key;
7367         struct extent_buffer *eb;
7368         int ret;
7369         int slot;
7370         int nread = 0;
7371
7372         if (path->slots[wc->level] < wc->reada_slot) {
7373                 wc->reada_count = wc->reada_count * 2 / 3;
7374                 wc->reada_count = max(wc->reada_count, 2);
7375         } else {
7376                 wc->reada_count = wc->reada_count * 3 / 2;
7377                 wc->reada_count = min_t(int, wc->reada_count,
7378                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7379         }
7380
7381         eb = path->nodes[wc->level];
7382         nritems = btrfs_header_nritems(eb);
7383         blocksize = root->nodesize;
7384
7385         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7386                 if (nread >= wc->reada_count)
7387                         break;
7388
7389                 cond_resched();
7390                 bytenr = btrfs_node_blockptr(eb, slot);
7391                 generation = btrfs_node_ptr_generation(eb, slot);
7392
7393                 if (slot == path->slots[wc->level])
7394                         goto reada;
7395
7396                 if (wc->stage == UPDATE_BACKREF &&
7397                     generation <= root->root_key.offset)
7398                         continue;
7399
7400                 /* We don't lock the tree block, it's OK to be racy here */
7401                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7402                                                wc->level - 1, 1, &refs,
7403                                                &flags);
7404                 /* We don't care about errors in readahead. */
7405                 if (ret < 0)
7406                         continue;
7407                 BUG_ON(refs == 0);
7408
7409                 if (wc->stage == DROP_REFERENCE) {
7410                         if (refs == 1)
7411                                 goto reada;
7412
7413                         if (wc->level == 1 &&
7414                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7415                                 continue;
7416                         if (!wc->update_ref ||
7417                             generation <= root->root_key.offset)
7418                                 continue;
7419                         btrfs_node_key_to_cpu(eb, &key, slot);
7420                         ret = btrfs_comp_cpu_keys(&key,
7421                                                   &wc->update_progress);
7422                         if (ret < 0)
7423                                 continue;
7424                 } else {
7425                         if (wc->level == 1 &&
7426                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7427                                 continue;
7428                 }
7429 reada:
7430                 readahead_tree_block(root, bytenr);
7431                 nread++;
7432         }
7433         wc->reada_slot = slot;
7434 }
7435
7436 static int account_leaf_items(struct btrfs_trans_handle *trans,
7437                               struct btrfs_root *root,
7438                               struct extent_buffer *eb)
7439 {
7440         int nr = btrfs_header_nritems(eb);
7441         int i, extent_type, ret;
7442         struct btrfs_key key;
7443         struct btrfs_file_extent_item *fi;
7444         u64 bytenr, num_bytes;
7445
7446         for (i = 0; i < nr; i++) {
7447                 btrfs_item_key_to_cpu(eb, &key, i);
7448
7449                 if (key.type != BTRFS_EXTENT_DATA_KEY)
7450                         continue;
7451
7452                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
7453                 /* filter out non qgroup-accountable extents  */
7454                 extent_type = btrfs_file_extent_type(eb, fi);
7455
7456                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
7457                         continue;
7458
7459                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
7460                 if (!bytenr)
7461                         continue;
7462
7463                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
7464
7465                 ret = btrfs_qgroup_record_ref(trans, root->fs_info,
7466                                               root->objectid,
7467                                               bytenr, num_bytes,
7468                                               BTRFS_QGROUP_OPER_SUB_SUBTREE, 0);
7469                 if (ret)
7470                         return ret;
7471         }
7472         return 0;
7473 }
7474
7475 /*
7476  * Walk up the tree from the bottom, freeing leaves and any interior
7477  * nodes which have had all slots visited. If a node (leaf or
7478  * interior) is freed, the node above it will have it's slot
7479  * incremented. The root node will never be freed.
7480  *
7481  * At the end of this function, we should have a path which has all
7482  * slots incremented to the next position for a search. If we need to
7483  * read a new node it will be NULL and the node above it will have the
7484  * correct slot selected for a later read.
7485  *
7486  * If we increment the root nodes slot counter past the number of
7487  * elements, 1 is returned to signal completion of the search.
7488  */
7489 static int adjust_slots_upwards(struct btrfs_root *root,
7490                                 struct btrfs_path *path, int root_level)
7491 {
7492         int level = 0;
7493         int nr, slot;
7494         struct extent_buffer *eb;
7495
7496         if (root_level == 0)
7497                 return 1;
7498
7499         while (level <= root_level) {
7500                 eb = path->nodes[level];
7501                 nr = btrfs_header_nritems(eb);
7502                 path->slots[level]++;
7503                 slot = path->slots[level];
7504                 if (slot >= nr || level == 0) {
7505                         /*
7506                          * Don't free the root -  we will detect this
7507                          * condition after our loop and return a
7508                          * positive value for caller to stop walking the tree.
7509                          */
7510                         if (level != root_level) {
7511                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7512                                 path->locks[level] = 0;
7513
7514                                 free_extent_buffer(eb);
7515                                 path->nodes[level] = NULL;
7516                                 path->slots[level] = 0;
7517                         }
7518                 } else {
7519                         /*
7520                          * We have a valid slot to walk back down
7521                          * from. Stop here so caller can process these
7522                          * new nodes.
7523                          */
7524                         break;
7525                 }
7526
7527                 level++;
7528         }
7529
7530         eb = path->nodes[root_level];
7531         if (path->slots[root_level] >= btrfs_header_nritems(eb))
7532                 return 1;
7533
7534         return 0;
7535 }
7536
7537 /*
7538  * root_eb is the subtree root and is locked before this function is called.
7539  */
7540 static int account_shared_subtree(struct btrfs_trans_handle *trans,
7541                                   struct btrfs_root *root,
7542                                   struct extent_buffer *root_eb,
7543                                   u64 root_gen,
7544                                   int root_level)
7545 {
7546         int ret = 0;
7547         int level;
7548         struct extent_buffer *eb = root_eb;
7549         struct btrfs_path *path = NULL;
7550
7551         BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
7552         BUG_ON(root_eb == NULL);
7553
7554         if (!root->fs_info->quota_enabled)
7555                 return 0;
7556
7557         if (!extent_buffer_uptodate(root_eb)) {
7558                 ret = btrfs_read_buffer(root_eb, root_gen);
7559                 if (ret)
7560                         goto out;
7561         }
7562
7563         if (root_level == 0) {
7564                 ret = account_leaf_items(trans, root, root_eb);
7565                 goto out;
7566         }
7567
7568         path = btrfs_alloc_path();
7569         if (!path)
7570                 return -ENOMEM;
7571
7572         /*
7573          * Walk down the tree.  Missing extent blocks are filled in as
7574          * we go. Metadata is accounted every time we read a new
7575          * extent block.
7576          *
7577          * When we reach a leaf, we account for file extent items in it,
7578          * walk back up the tree (adjusting slot pointers as we go)
7579          * and restart the search process.
7580          */
7581         extent_buffer_get(root_eb); /* For path */
7582         path->nodes[root_level] = root_eb;
7583         path->slots[root_level] = 0;
7584         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
7585 walk_down:
7586         level = root_level;
7587         while (level >= 0) {
7588                 if (path->nodes[level] == NULL) {
7589                         int parent_slot;
7590                         u64 child_gen;
7591                         u64 child_bytenr;
7592
7593                         /* We need to get child blockptr/gen from
7594                          * parent before we can read it. */
7595                         eb = path->nodes[level + 1];
7596                         parent_slot = path->slots[level + 1];
7597                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
7598                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
7599
7600                         eb = read_tree_block(root, child_bytenr, child_gen);
7601                         if (!eb || !extent_buffer_uptodate(eb)) {
7602                                 ret = -EIO;
7603                                 goto out;
7604                         }
7605
7606                         path->nodes[level] = eb;
7607                         path->slots[level] = 0;
7608
7609                         btrfs_tree_read_lock(eb);
7610                         btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
7611                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
7612
7613                         ret = btrfs_qgroup_record_ref(trans, root->fs_info,
7614                                                 root->objectid,
7615                                                 child_bytenr,
7616                                                 root->nodesize,
7617                                                 BTRFS_QGROUP_OPER_SUB_SUBTREE,
7618                                                 0);
7619                         if (ret)
7620                                 goto out;
7621
7622                 }
7623
7624                 if (level == 0) {
7625                         ret = account_leaf_items(trans, root, path->nodes[level]);
7626                         if (ret)
7627                                 goto out;
7628
7629                         /* Nonzero return here means we completed our search */
7630                         ret = adjust_slots_upwards(root, path, root_level);
7631                         if (ret)
7632                                 break;
7633
7634                         /* Restart search with new slots */
7635                         goto walk_down;
7636                 }
7637
7638                 level--;
7639         }
7640
7641         ret = 0;
7642 out:
7643         btrfs_free_path(path);
7644
7645         return ret;
7646 }
7647
7648 /*
7649  * helper to process tree block while walking down the tree.
7650  *
7651  * when wc->stage == UPDATE_BACKREF, this function updates
7652  * back refs for pointers in the block.
7653  *
7654  * NOTE: return value 1 means we should stop walking down.
7655  */
7656 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7657                                    struct btrfs_root *root,
7658                                    struct btrfs_path *path,
7659                                    struct walk_control *wc, int lookup_info)
7660 {
7661         int level = wc->level;
7662         struct extent_buffer *eb = path->nodes[level];
7663         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7664         int ret;
7665
7666         if (wc->stage == UPDATE_BACKREF &&
7667             btrfs_header_owner(eb) != root->root_key.objectid)
7668                 return 1;
7669
7670         /*
7671          * when reference count of tree block is 1, it won't increase
7672          * again. once full backref flag is set, we never clear it.
7673          */
7674         if (lookup_info &&
7675             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7676              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7677                 BUG_ON(!path->locks[level]);
7678                 ret = btrfs_lookup_extent_info(trans, root,
7679                                                eb->start, level, 1,
7680                                                &wc->refs[level],
7681                                                &wc->flags[level]);
7682                 BUG_ON(ret == -ENOMEM);
7683                 if (ret)
7684                         return ret;
7685                 BUG_ON(wc->refs[level] == 0);
7686         }
7687
7688         if (wc->stage == DROP_REFERENCE) {
7689                 if (wc->refs[level] > 1)
7690                         return 1;
7691
7692                 if (path->locks[level] && !wc->keep_locks) {
7693                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7694                         path->locks[level] = 0;
7695                 }
7696                 return 0;
7697         }
7698
7699         /* wc->stage == UPDATE_BACKREF */
7700         if (!(wc->flags[level] & flag)) {
7701                 BUG_ON(!path->locks[level]);
7702                 ret = btrfs_inc_ref(trans, root, eb, 1);
7703                 BUG_ON(ret); /* -ENOMEM */
7704                 ret = btrfs_dec_ref(trans, root, eb, 0);
7705                 BUG_ON(ret); /* -ENOMEM */
7706                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7707                                                   eb->len, flag,
7708                                                   btrfs_header_level(eb), 0);
7709                 BUG_ON(ret); /* -ENOMEM */
7710                 wc->flags[level] |= flag;
7711         }
7712
7713         /*
7714          * the block is shared by multiple trees, so it's not good to
7715          * keep the tree lock
7716          */
7717         if (path->locks[level] && level > 0) {
7718                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7719                 path->locks[level] = 0;
7720         }
7721         return 0;
7722 }
7723
7724 /*
7725  * helper to process tree block pointer.
7726  *
7727  * when wc->stage == DROP_REFERENCE, this function checks
7728  * reference count of the block pointed to. if the block
7729  * is shared and we need update back refs for the subtree
7730  * rooted at the block, this function changes wc->stage to
7731  * UPDATE_BACKREF. if the block is shared and there is no
7732  * need to update back, this function drops the reference
7733  * to the block.
7734  *
7735  * NOTE: return value 1 means we should stop walking down.
7736  */
7737 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
7738                                  struct btrfs_root *root,
7739                                  struct btrfs_path *path,
7740                                  struct walk_control *wc, int *lookup_info)
7741 {
7742         u64 bytenr;
7743         u64 generation;
7744         u64 parent;
7745         u32 blocksize;
7746         struct btrfs_key key;
7747         struct extent_buffer *next;
7748         int level = wc->level;
7749         int reada = 0;
7750         int ret = 0;
7751         bool need_account = false;
7752
7753         generation = btrfs_node_ptr_generation(path->nodes[level],
7754                                                path->slots[level]);
7755         /*
7756          * if the lower level block was created before the snapshot
7757          * was created, we know there is no need to update back refs
7758          * for the subtree
7759          */
7760         if (wc->stage == UPDATE_BACKREF &&
7761             generation <= root->root_key.offset) {
7762                 *lookup_info = 1;
7763                 return 1;
7764         }
7765
7766         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
7767         blocksize = root->nodesize;
7768
7769         next = btrfs_find_tree_block(root, bytenr);
7770         if (!next) {
7771                 next = btrfs_find_create_tree_block(root, bytenr);
7772                 if (!next)
7773                         return -ENOMEM;
7774                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
7775                                                level - 1);
7776                 reada = 1;
7777         }
7778         btrfs_tree_lock(next);
7779         btrfs_set_lock_blocking(next);
7780
7781         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
7782                                        &wc->refs[level - 1],
7783                                        &wc->flags[level - 1]);
7784         if (ret < 0) {
7785                 btrfs_tree_unlock(next);
7786                 return ret;
7787         }
7788
7789         if (unlikely(wc->refs[level - 1] == 0)) {
7790                 btrfs_err(root->fs_info, "Missing references.");
7791                 BUG();
7792         }
7793         *lookup_info = 0;
7794
7795         if (wc->stage == DROP_REFERENCE) {
7796                 if (wc->refs[level - 1] > 1) {
7797                         need_account = true;
7798                         if (level == 1 &&
7799                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7800                                 goto skip;
7801
7802                         if (!wc->update_ref ||
7803                             generation <= root->root_key.offset)
7804                                 goto skip;
7805
7806                         btrfs_node_key_to_cpu(path->nodes[level], &key,
7807                                               path->slots[level]);
7808                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
7809                         if (ret < 0)
7810                                 goto skip;
7811
7812                         wc->stage = UPDATE_BACKREF;
7813                         wc->shared_level = level - 1;
7814                 }
7815         } else {
7816                 if (level == 1 &&
7817                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7818                         goto skip;
7819         }
7820
7821         if (!btrfs_buffer_uptodate(next, generation, 0)) {
7822                 btrfs_tree_unlock(next);
7823                 free_extent_buffer(next);
7824                 next = NULL;
7825                 *lookup_info = 1;
7826         }
7827
7828         if (!next) {
7829                 if (reada && level == 1)
7830                         reada_walk_down(trans, root, wc, path);
7831                 next = read_tree_block(root, bytenr, generation);
7832                 if (!next || !extent_buffer_uptodate(next)) {
7833                         free_extent_buffer(next);
7834                         return -EIO;
7835                 }
7836                 btrfs_tree_lock(next);
7837                 btrfs_set_lock_blocking(next);
7838         }
7839
7840         level--;
7841         BUG_ON(level != btrfs_header_level(next));
7842         path->nodes[level] = next;
7843         path->slots[level] = 0;
7844         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7845         wc->level = level;
7846         if (wc->level == 1)
7847                 wc->reada_slot = 0;
7848         return 0;
7849 skip:
7850         wc->refs[level - 1] = 0;
7851         wc->flags[level - 1] = 0;
7852         if (wc->stage == DROP_REFERENCE) {
7853                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
7854                         parent = path->nodes[level]->start;
7855                 } else {
7856                         BUG_ON(root->root_key.objectid !=
7857                                btrfs_header_owner(path->nodes[level]));
7858                         parent = 0;
7859                 }
7860
7861                 if (need_account) {
7862                         ret = account_shared_subtree(trans, root, next,
7863                                                      generation, level - 1);
7864                         if (ret) {
7865                                 printk_ratelimited(KERN_ERR "BTRFS: %s Error "
7866                                         "%d accounting shared subtree. Quota "
7867                                         "is out of sync, rescan required.\n",
7868                                         root->fs_info->sb->s_id, ret);
7869                         }
7870                 }
7871                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
7872                                 root->root_key.objectid, level - 1, 0, 0);
7873                 BUG_ON(ret); /* -ENOMEM */
7874         }
7875         btrfs_tree_unlock(next);
7876         free_extent_buffer(next);
7877         *lookup_info = 1;
7878         return 1;
7879 }
7880
7881 /*
7882  * helper to process tree block while walking up the tree.
7883  *
7884  * when wc->stage == DROP_REFERENCE, this function drops
7885  * reference count on the block.
7886  *
7887  * when wc->stage == UPDATE_BACKREF, this function changes
7888  * wc->stage back to DROP_REFERENCE if we changed wc->stage
7889  * to UPDATE_BACKREF previously while processing the block.
7890  *
7891  * NOTE: return value 1 means we should stop walking up.
7892  */
7893 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
7894                                  struct btrfs_root *root,
7895                                  struct btrfs_path *path,
7896                                  struct walk_control *wc)
7897 {
7898         int ret;
7899         int level = wc->level;
7900         struct extent_buffer *eb = path->nodes[level];
7901         u64 parent = 0;
7902
7903         if (wc->stage == UPDATE_BACKREF) {
7904                 BUG_ON(wc->shared_level < level);
7905                 if (level < wc->shared_level)
7906                         goto out;
7907
7908                 ret = find_next_key(path, level + 1, &wc->update_progress);
7909                 if (ret > 0)
7910                         wc->update_ref = 0;
7911
7912                 wc->stage = DROP_REFERENCE;
7913                 wc->shared_level = -1;
7914                 path->slots[level] = 0;
7915
7916                 /*
7917                  * check reference count again if the block isn't locked.
7918                  * we should start walking down the tree again if reference
7919                  * count is one.
7920                  */
7921                 if (!path->locks[level]) {
7922                         BUG_ON(level == 0);
7923                         btrfs_tree_lock(eb);
7924                         btrfs_set_lock_blocking(eb);
7925                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7926
7927                         ret = btrfs_lookup_extent_info(trans, root,
7928                                                        eb->start, level, 1,
7929                                                        &wc->refs[level],
7930                                                        &wc->flags[level]);
7931                         if (ret < 0) {
7932                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7933                                 path->locks[level] = 0;
7934                                 return ret;
7935                         }
7936                         BUG_ON(wc->refs[level] == 0);
7937                         if (wc->refs[level] == 1) {
7938                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7939                                 path->locks[level] = 0;
7940                                 return 1;
7941                         }
7942                 }
7943         }
7944
7945         /* wc->stage == DROP_REFERENCE */
7946         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7947
7948         if (wc->refs[level] == 1) {
7949                 if (level == 0) {
7950                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7951                                 ret = btrfs_dec_ref(trans, root, eb, 1);
7952                         else
7953                                 ret = btrfs_dec_ref(trans, root, eb, 0);
7954                         BUG_ON(ret); /* -ENOMEM */
7955                         ret = account_leaf_items(trans, root, eb);
7956                         if (ret) {
7957                                 printk_ratelimited(KERN_ERR "BTRFS: %s Error "
7958                                         "%d accounting leaf items. Quota "
7959                                         "is out of sync, rescan required.\n",
7960                                         root->fs_info->sb->s_id, ret);
7961                         }
7962                 }
7963                 /* make block locked assertion in clean_tree_block happy */
7964                 if (!path->locks[level] &&
7965                     btrfs_header_generation(eb) == trans->transid) {
7966                         btrfs_tree_lock(eb);
7967                         btrfs_set_lock_blocking(eb);
7968                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7969                 }
7970                 clean_tree_block(trans, root, eb);
7971         }
7972
7973         if (eb == root->node) {
7974                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7975                         parent = eb->start;
7976                 else
7977                         BUG_ON(root->root_key.objectid !=
7978                                btrfs_header_owner(eb));
7979         } else {
7980                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7981                         parent = path->nodes[level + 1]->start;
7982                 else
7983                         BUG_ON(root->root_key.objectid !=
7984                                btrfs_header_owner(path->nodes[level + 1]));
7985         }
7986
7987         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
7988 out:
7989         wc->refs[level] = 0;
7990         wc->flags[level] = 0;
7991         return 0;
7992 }
7993
7994 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
7995                                    struct btrfs_root *root,
7996                                    struct btrfs_path *path,
7997                                    struct walk_control *wc)
7998 {
7999         int level = wc->level;
8000         int lookup_info = 1;
8001         int ret;
8002
8003         while (level >= 0) {
8004                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8005                 if (ret > 0)
8006                         break;
8007
8008                 if (level == 0)
8009                         break;
8010
8011                 if (path->slots[level] >=
8012                     btrfs_header_nritems(path->nodes[level]))
8013                         break;
8014
8015                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8016                 if (ret > 0) {
8017                         path->slots[level]++;
8018                         continue;
8019                 } else if (ret < 0)
8020                         return ret;
8021                 level = wc->level;
8022         }
8023         return 0;
8024 }
8025
8026 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8027                                  struct btrfs_root *root,
8028                                  struct btrfs_path *path,
8029                                  struct walk_control *wc, int max_level)
8030 {
8031         int level = wc->level;
8032         int ret;
8033
8034         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8035         while (level < max_level && path->nodes[level]) {
8036                 wc->level = level;
8037                 if (path->slots[level] + 1 <
8038                     btrfs_header_nritems(path->nodes[level])) {
8039                         path->slots[level]++;
8040                         return 0;
8041                 } else {
8042                         ret = walk_up_proc(trans, root, path, wc);
8043                         if (ret > 0)
8044                                 return 0;
8045
8046                         if (path->locks[level]) {
8047                                 btrfs_tree_unlock_rw(path->nodes[level],
8048                                                      path->locks[level]);
8049                                 path->locks[level] = 0;
8050                         }
8051                         free_extent_buffer(path->nodes[level]);
8052                         path->nodes[level] = NULL;
8053                         level++;
8054                 }
8055         }
8056         return 1;
8057 }
8058
8059 /*
8060  * drop a subvolume tree.
8061  *
8062  * this function traverses the tree freeing any blocks that only
8063  * referenced by the tree.
8064  *
8065  * when a shared tree block is found. this function decreases its
8066  * reference count by one. if update_ref is true, this function
8067  * also make sure backrefs for the shared block and all lower level
8068  * blocks are properly updated.
8069  *
8070  * If called with for_reloc == 0, may exit early with -EAGAIN
8071  */
8072 int btrfs_drop_snapshot(struct btrfs_root *root,
8073                          struct btrfs_block_rsv *block_rsv, int update_ref,
8074                          int for_reloc)
8075 {
8076         struct btrfs_path *path;
8077         struct btrfs_trans_handle *trans;
8078         struct btrfs_root *tree_root = root->fs_info->tree_root;
8079         struct btrfs_root_item *root_item = &root->root_item;
8080         struct walk_control *wc;
8081         struct btrfs_key key;
8082         int err = 0;
8083         int ret;
8084         int level;
8085         bool root_dropped = false;
8086
8087         btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
8088
8089         path = btrfs_alloc_path();
8090         if (!path) {
8091                 err = -ENOMEM;
8092                 goto out;
8093         }
8094
8095         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8096         if (!wc) {
8097                 btrfs_free_path(path);
8098                 err = -ENOMEM;
8099                 goto out;
8100         }
8101
8102         trans = btrfs_start_transaction(tree_root, 0);
8103         if (IS_ERR(trans)) {
8104                 err = PTR_ERR(trans);
8105                 goto out_free;
8106         }
8107
8108         if (block_rsv)
8109                 trans->block_rsv = block_rsv;
8110
8111         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8112                 level = btrfs_header_level(root->node);
8113                 path->nodes[level] = btrfs_lock_root_node(root);
8114                 btrfs_set_lock_blocking(path->nodes[level]);
8115                 path->slots[level] = 0;
8116                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8117                 memset(&wc->update_progress, 0,
8118                        sizeof(wc->update_progress));
8119         } else {
8120                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8121                 memcpy(&wc->update_progress, &key,
8122                        sizeof(wc->update_progress));
8123
8124                 level = root_item->drop_level;
8125                 BUG_ON(level == 0);
8126                 path->lowest_level = level;
8127                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8128                 path->lowest_level = 0;
8129                 if (ret < 0) {
8130                         err = ret;
8131                         goto out_end_trans;
8132                 }
8133                 WARN_ON(ret > 0);
8134
8135                 /*
8136                  * unlock our path, this is safe because only this
8137                  * function is allowed to delete this snapshot
8138                  */
8139                 btrfs_unlock_up_safe(path, 0);
8140
8141                 level = btrfs_header_level(root->node);
8142                 while (1) {
8143                         btrfs_tree_lock(path->nodes[level]);
8144                         btrfs_set_lock_blocking(path->nodes[level]);
8145                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8146
8147                         ret = btrfs_lookup_extent_info(trans, root,
8148                                                 path->nodes[level]->start,
8149                                                 level, 1, &wc->refs[level],
8150                                                 &wc->flags[level]);
8151                         if (ret < 0) {
8152                                 err = ret;
8153                                 goto out_end_trans;
8154                         }
8155                         BUG_ON(wc->refs[level] == 0);
8156
8157                         if (level == root_item->drop_level)
8158                                 break;
8159
8160                         btrfs_tree_unlock(path->nodes[level]);
8161                         path->locks[level] = 0;
8162                         WARN_ON(wc->refs[level] != 1);
8163                         level--;
8164                 }
8165         }
8166
8167         wc->level = level;
8168         wc->shared_level = -1;
8169         wc->stage = DROP_REFERENCE;
8170         wc->update_ref = update_ref;
8171         wc->keep_locks = 0;
8172         wc->for_reloc = for_reloc;
8173         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8174
8175         while (1) {
8176
8177                 ret = walk_down_tree(trans, root, path, wc);
8178                 if (ret < 0) {
8179                         err = ret;
8180                         break;
8181                 }
8182
8183                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
8184                 if (ret < 0) {
8185                         err = ret;
8186                         break;
8187                 }
8188
8189                 if (ret > 0) {
8190                         BUG_ON(wc->stage != DROP_REFERENCE);
8191                         break;
8192                 }
8193
8194                 if (wc->stage == DROP_REFERENCE) {
8195                         level = wc->level;
8196                         btrfs_node_key(path->nodes[level],
8197                                        &root_item->drop_progress,
8198                                        path->slots[level]);
8199                         root_item->drop_level = level;
8200                 }
8201
8202                 BUG_ON(wc->level == 0);
8203                 if (btrfs_should_end_transaction(trans, tree_root) ||
8204                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
8205                         ret = btrfs_update_root(trans, tree_root,
8206                                                 &root->root_key,
8207                                                 root_item);
8208                         if (ret) {
8209                                 btrfs_abort_transaction(trans, tree_root, ret);
8210                                 err = ret;
8211                                 goto out_end_trans;
8212                         }
8213
8214                         /*
8215                          * Qgroup update accounting is run from
8216                          * delayed ref handling. This usually works
8217                          * out because delayed refs are normally the
8218                          * only way qgroup updates are added. However,
8219                          * we may have added updates during our tree
8220                          * walk so run qgroups here to make sure we
8221                          * don't lose any updates.
8222                          */
8223                         ret = btrfs_delayed_qgroup_accounting(trans,
8224                                                               root->fs_info);
8225                         if (ret)
8226                                 printk_ratelimited(KERN_ERR "BTRFS: Failure %d "
8227                                                    "running qgroup updates "
8228                                                    "during snapshot delete. "
8229                                                    "Quota is out of sync, "
8230                                                    "rescan required.\n", ret);
8231
8232                         btrfs_end_transaction_throttle(trans, tree_root);
8233                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
8234                                 pr_debug("BTRFS: drop snapshot early exit\n");
8235                                 err = -EAGAIN;
8236                                 goto out_free;
8237                         }
8238
8239                         trans = btrfs_start_transaction(tree_root, 0);
8240                         if (IS_ERR(trans)) {
8241                                 err = PTR_ERR(trans);
8242                                 goto out_free;
8243                         }
8244                         if (block_rsv)
8245                                 trans->block_rsv = block_rsv;
8246                 }
8247         }
8248         btrfs_release_path(path);
8249         if (err)
8250                 goto out_end_trans;
8251
8252         ret = btrfs_del_root(trans, tree_root, &root->root_key);
8253         if (ret) {
8254                 btrfs_abort_transaction(trans, tree_root, ret);
8255                 goto out_end_trans;
8256         }
8257
8258         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
8259                 ret = btrfs_find_root(tree_root, &root->root_key, path,
8260                                       NULL, NULL);
8261                 if (ret < 0) {
8262                         btrfs_abort_transaction(trans, tree_root, ret);
8263                         err = ret;
8264                         goto out_end_trans;
8265                 } else if (ret > 0) {
8266                         /* if we fail to delete the orphan item this time
8267                          * around, it'll get picked up the next time.
8268                          *
8269                          * The most common failure here is just -ENOENT.
8270                          */
8271                         btrfs_del_orphan_item(trans, tree_root,
8272                                               root->root_key.objectid);
8273                 }
8274         }
8275
8276         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
8277                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
8278         } else {
8279                 free_extent_buffer(root->node);
8280                 free_extent_buffer(root->commit_root);
8281                 btrfs_put_fs_root(root);
8282         }
8283         root_dropped = true;
8284 out_end_trans:
8285         ret = btrfs_delayed_qgroup_accounting(trans, tree_root->fs_info);
8286         if (ret)
8287                 printk_ratelimited(KERN_ERR "BTRFS: Failure %d "
8288                                    "running qgroup updates "
8289                                    "during snapshot delete. "
8290                                    "Quota is out of sync, "
8291                                    "rescan required.\n", ret);
8292
8293         btrfs_end_transaction_throttle(trans, tree_root);
8294 out_free:
8295         kfree(wc);
8296         btrfs_free_path(path);
8297 out:
8298         /*
8299          * So if we need to stop dropping the snapshot for whatever reason we
8300          * need to make sure to add it back to the dead root list so that we
8301          * keep trying to do the work later.  This also cleans up roots if we
8302          * don't have it in the radix (like when we recover after a power fail
8303          * or unmount) so we don't leak memory.
8304          */
8305         if (!for_reloc && root_dropped == false)
8306                 btrfs_add_dead_root(root);
8307         if (err && err != -EAGAIN)
8308                 btrfs_std_error(root->fs_info, err);
8309         return err;
8310 }
8311
8312 /*
8313  * drop subtree rooted at tree block 'node'.
8314  *
8315  * NOTE: this function will unlock and release tree block 'node'
8316  * only used by relocation code
8317  */
8318 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
8319                         struct btrfs_root *root,
8320                         struct extent_buffer *node,
8321                         struct extent_buffer *parent)
8322 {
8323         struct btrfs_path *path;
8324         struct walk_control *wc;
8325         int level;
8326         int parent_level;
8327         int ret = 0;
8328         int wret;
8329
8330         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
8331
8332         path = btrfs_alloc_path();
8333         if (!path)
8334                 return -ENOMEM;
8335
8336         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8337         if (!wc) {
8338                 btrfs_free_path(path);
8339                 return -ENOMEM;
8340         }
8341
8342         btrfs_assert_tree_locked(parent);
8343         parent_level = btrfs_header_level(parent);
8344         extent_buffer_get(parent);
8345         path->nodes[parent_level] = parent;
8346         path->slots[parent_level] = btrfs_header_nritems(parent);
8347
8348         btrfs_assert_tree_locked(node);
8349         level = btrfs_header_level(node);
8350         path->nodes[level] = node;
8351         path->slots[level] = 0;
8352         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8353
8354         wc->refs[parent_level] = 1;
8355         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8356         wc->level = level;
8357         wc->shared_level = -1;
8358         wc->stage = DROP_REFERENCE;
8359         wc->update_ref = 0;
8360         wc->keep_locks = 1;
8361         wc->for_reloc = 1;
8362         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8363
8364         while (1) {
8365                 wret = walk_down_tree(trans, root, path, wc);
8366                 if (wret < 0) {
8367                         ret = wret;
8368                         break;
8369                 }
8370
8371                 wret = walk_up_tree(trans, root, path, wc, parent_level);
8372                 if (wret < 0)
8373                         ret = wret;
8374                 if (wret != 0)
8375                         break;
8376         }
8377
8378         kfree(wc);
8379         btrfs_free_path(path);
8380         return ret;
8381 }
8382
8383 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
8384 {
8385         u64 num_devices;
8386         u64 stripped;
8387
8388         /*
8389          * if restripe for this chunk_type is on pick target profile and
8390          * return, otherwise do the usual balance
8391          */
8392         stripped = get_restripe_target(root->fs_info, flags);
8393         if (stripped)
8394                 return extended_to_chunk(stripped);
8395
8396         num_devices = root->fs_info->fs_devices->rw_devices;
8397
8398         stripped = BTRFS_BLOCK_GROUP_RAID0 |
8399                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
8400                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
8401
8402         if (num_devices == 1) {
8403                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8404                 stripped = flags & ~stripped;
8405
8406                 /* turn raid0 into single device chunks */
8407                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
8408                         return stripped;
8409
8410                 /* turn mirroring into duplication */
8411                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
8412                              BTRFS_BLOCK_GROUP_RAID10))
8413                         return stripped | BTRFS_BLOCK_GROUP_DUP;
8414         } else {
8415                 /* they already had raid on here, just return */
8416                 if (flags & stripped)
8417                         return flags;
8418
8419                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8420                 stripped = flags & ~stripped;
8421
8422                 /* switch duplicated blocks with raid1 */
8423                 if (flags & BTRFS_BLOCK_GROUP_DUP)
8424                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
8425
8426                 /* this is drive concat, leave it alone */
8427         }
8428
8429         return flags;
8430 }
8431
8432 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
8433 {
8434         struct btrfs_space_info *sinfo = cache->space_info;
8435         u64 num_bytes;
8436         u64 min_allocable_bytes;
8437         int ret = -ENOSPC;
8438
8439
8440         /*
8441          * We need some metadata space and system metadata space for
8442          * allocating chunks in some corner cases until we force to set
8443          * it to be readonly.
8444          */
8445         if ((sinfo->flags &
8446              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
8447             !force)
8448                 min_allocable_bytes = 1 * 1024 * 1024;
8449         else
8450                 min_allocable_bytes = 0;
8451
8452         spin_lock(&sinfo->lock);
8453         spin_lock(&cache->lock);
8454
8455         if (cache->ro) {
8456                 ret = 0;
8457                 goto out;
8458         }
8459
8460         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8461                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8462
8463         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
8464             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
8465             min_allocable_bytes <= sinfo->total_bytes) {
8466                 sinfo->bytes_readonly += num_bytes;
8467                 cache->ro = 1;
8468                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
8469                 ret = 0;
8470         }
8471 out:
8472         spin_unlock(&cache->lock);
8473         spin_unlock(&sinfo->lock);
8474         return ret;
8475 }
8476
8477 int btrfs_set_block_group_ro(struct btrfs_root *root,
8478                              struct btrfs_block_group_cache *cache)
8479
8480 {
8481         struct btrfs_trans_handle *trans;
8482         u64 alloc_flags;
8483         int ret;
8484
8485         BUG_ON(cache->ro);
8486
8487         trans = btrfs_join_transaction(root);
8488         if (IS_ERR(trans))
8489                 return PTR_ERR(trans);
8490
8491         ret = set_block_group_ro(cache, 0);
8492         if (!ret)
8493                 goto out;
8494         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
8495         ret = do_chunk_alloc(trans, root, alloc_flags,
8496                              CHUNK_ALLOC_FORCE);
8497         if (ret < 0)
8498                 goto out;
8499         ret = set_block_group_ro(cache, 0);
8500 out:
8501         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
8502                 alloc_flags = update_block_group_flags(root, cache->flags);
8503                 check_system_chunk(trans, root, alloc_flags);
8504         }
8505
8506         btrfs_end_transaction(trans, root);
8507         return ret;
8508 }
8509
8510 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
8511                             struct btrfs_root *root, u64 type)
8512 {
8513         u64 alloc_flags = get_alloc_profile(root, type);
8514         return do_chunk_alloc(trans, root, alloc_flags,
8515                               CHUNK_ALLOC_FORCE);
8516 }
8517
8518 /*
8519  * helper to account the unused space of all the readonly block group in the
8520  * space_info. takes mirrors into account.
8521  */
8522 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
8523 {
8524         struct btrfs_block_group_cache *block_group;
8525         u64 free_bytes = 0;
8526         int factor;
8527
8528         /* It's df, we don't care if it's racey */
8529         if (list_empty(&sinfo->ro_bgs))
8530                 return 0;
8531
8532         spin_lock(&sinfo->lock);
8533         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
8534                 spin_lock(&block_group->lock);
8535
8536                 if (!block_group->ro) {
8537                         spin_unlock(&block_group->lock);
8538                         continue;
8539                 }
8540
8541                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
8542                                           BTRFS_BLOCK_GROUP_RAID10 |
8543                                           BTRFS_BLOCK_GROUP_DUP))
8544                         factor = 2;
8545                 else
8546                         factor = 1;
8547
8548                 free_bytes += (block_group->key.offset -
8549                                btrfs_block_group_used(&block_group->item)) *
8550                                factor;
8551
8552                 spin_unlock(&block_group->lock);
8553         }
8554         spin_unlock(&sinfo->lock);
8555
8556         return free_bytes;
8557 }
8558
8559 void btrfs_set_block_group_rw(struct btrfs_root *root,
8560                               struct btrfs_block_group_cache *cache)
8561 {
8562         struct btrfs_space_info *sinfo = cache->space_info;
8563         u64 num_bytes;
8564
8565         BUG_ON(!cache->ro);
8566
8567         spin_lock(&sinfo->lock);
8568         spin_lock(&cache->lock);
8569         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8570                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8571         sinfo->bytes_readonly -= num_bytes;
8572         cache->ro = 0;
8573         list_del_init(&cache->ro_list);
8574         spin_unlock(&cache->lock);
8575         spin_unlock(&sinfo->lock);
8576 }
8577
8578 /*
8579  * checks to see if its even possible to relocate this block group.
8580  *
8581  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
8582  * ok to go ahead and try.
8583  */
8584 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
8585 {
8586         struct btrfs_block_group_cache *block_group;
8587         struct btrfs_space_info *space_info;
8588         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
8589         struct btrfs_device *device;
8590         struct btrfs_trans_handle *trans;
8591         u64 min_free;
8592         u64 dev_min = 1;
8593         u64 dev_nr = 0;
8594         u64 target;
8595         int index;
8596         int full = 0;
8597         int ret = 0;
8598
8599         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
8600
8601         /* odd, couldn't find the block group, leave it alone */
8602         if (!block_group)
8603                 return -1;
8604
8605         min_free = btrfs_block_group_used(&block_group->item);
8606
8607         /* no bytes used, we're good */
8608         if (!min_free)
8609                 goto out;
8610
8611         space_info = block_group->space_info;
8612         spin_lock(&space_info->lock);
8613
8614         full = space_info->full;
8615
8616         /*
8617          * if this is the last block group we have in this space, we can't
8618          * relocate it unless we're able to allocate a new chunk below.
8619          *
8620          * Otherwise, we need to make sure we have room in the space to handle
8621          * all of the extents from this block group.  If we can, we're good
8622          */
8623         if ((space_info->total_bytes != block_group->key.offset) &&
8624             (space_info->bytes_used + space_info->bytes_reserved +
8625              space_info->bytes_pinned + space_info->bytes_readonly +
8626              min_free < space_info->total_bytes)) {
8627                 spin_unlock(&space_info->lock);
8628                 goto out;
8629         }
8630         spin_unlock(&space_info->lock);
8631
8632         /*
8633          * ok we don't have enough space, but maybe we have free space on our
8634          * devices to allocate new chunks for relocation, so loop through our
8635          * alloc devices and guess if we have enough space.  if this block
8636          * group is going to be restriped, run checks against the target
8637          * profile instead of the current one.
8638          */
8639         ret = -1;
8640
8641         /*
8642          * index:
8643          *      0: raid10
8644          *      1: raid1
8645          *      2: dup
8646          *      3: raid0
8647          *      4: single
8648          */
8649         target = get_restripe_target(root->fs_info, block_group->flags);
8650         if (target) {
8651                 index = __get_raid_index(extended_to_chunk(target));
8652         } else {
8653                 /*
8654                  * this is just a balance, so if we were marked as full
8655                  * we know there is no space for a new chunk
8656                  */
8657                 if (full)
8658                         goto out;
8659
8660                 index = get_block_group_index(block_group);
8661         }
8662
8663         if (index == BTRFS_RAID_RAID10) {
8664                 dev_min = 4;
8665                 /* Divide by 2 */
8666                 min_free >>= 1;
8667         } else if (index == BTRFS_RAID_RAID1) {
8668                 dev_min = 2;
8669         } else if (index == BTRFS_RAID_DUP) {
8670                 /* Multiply by 2 */
8671                 min_free <<= 1;
8672         } else if (index == BTRFS_RAID_RAID0) {
8673                 dev_min = fs_devices->rw_devices;
8674                 do_div(min_free, dev_min);
8675         }
8676
8677         /* We need to do this so that we can look at pending chunks */
8678         trans = btrfs_join_transaction(root);
8679         if (IS_ERR(trans)) {
8680                 ret = PTR_ERR(trans);
8681                 goto out;
8682         }
8683
8684         mutex_lock(&root->fs_info->chunk_mutex);
8685         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8686                 u64 dev_offset;
8687
8688                 /*
8689                  * check to make sure we can actually find a chunk with enough
8690                  * space to fit our block group in.
8691                  */
8692                 if (device->total_bytes > device->bytes_used + min_free &&
8693                     !device->is_tgtdev_for_dev_replace) {
8694                         ret = find_free_dev_extent(trans, device, min_free,
8695                                                    &dev_offset, NULL);
8696                         if (!ret)
8697                                 dev_nr++;
8698
8699                         if (dev_nr >= dev_min)
8700                                 break;
8701
8702                         ret = -1;
8703                 }
8704         }
8705         mutex_unlock(&root->fs_info->chunk_mutex);
8706         btrfs_end_transaction(trans, root);
8707 out:
8708         btrfs_put_block_group(block_group);
8709         return ret;
8710 }
8711
8712 static int find_first_block_group(struct btrfs_root *root,
8713                 struct btrfs_path *path, struct btrfs_key *key)
8714 {
8715         int ret = 0;
8716         struct btrfs_key found_key;
8717         struct extent_buffer *leaf;
8718         int slot;
8719
8720         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
8721         if (ret < 0)
8722                 goto out;
8723
8724         while (1) {
8725                 slot = path->slots[0];
8726                 leaf = path->nodes[0];
8727                 if (slot >= btrfs_header_nritems(leaf)) {
8728                         ret = btrfs_next_leaf(root, path);
8729                         if (ret == 0)
8730                                 continue;
8731                         if (ret < 0)
8732                                 goto out;
8733                         break;
8734                 }
8735                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
8736
8737                 if (found_key.objectid >= key->objectid &&
8738                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
8739                         ret = 0;
8740                         goto out;
8741                 }
8742                 path->slots[0]++;
8743         }
8744 out:
8745         return ret;
8746 }
8747
8748 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
8749 {
8750         struct btrfs_block_group_cache *block_group;
8751         u64 last = 0;
8752
8753         while (1) {
8754                 struct inode *inode;
8755
8756                 block_group = btrfs_lookup_first_block_group(info, last);
8757                 while (block_group) {
8758                         spin_lock(&block_group->lock);
8759                         if (block_group->iref)
8760                                 break;
8761                         spin_unlock(&block_group->lock);
8762                         block_group = next_block_group(info->tree_root,
8763                                                        block_group);
8764                 }
8765                 if (!block_group) {
8766                         if (last == 0)
8767                                 break;
8768                         last = 0;
8769                         continue;
8770                 }
8771
8772                 inode = block_group->inode;
8773                 block_group->iref = 0;
8774                 block_group->inode = NULL;
8775                 spin_unlock(&block_group->lock);
8776                 iput(inode);
8777                 last = block_group->key.objectid + block_group->key.offset;
8778                 btrfs_put_block_group(block_group);
8779         }
8780 }
8781
8782 int btrfs_free_block_groups(struct btrfs_fs_info *info)
8783 {
8784         struct btrfs_block_group_cache *block_group;
8785         struct btrfs_space_info *space_info;
8786         struct btrfs_caching_control *caching_ctl;
8787         struct rb_node *n;
8788
8789         down_write(&info->commit_root_sem);
8790         while (!list_empty(&info->caching_block_groups)) {
8791                 caching_ctl = list_entry(info->caching_block_groups.next,
8792                                          struct btrfs_caching_control, list);
8793                 list_del(&caching_ctl->list);
8794                 put_caching_control(caching_ctl);
8795         }
8796         up_write(&info->commit_root_sem);
8797
8798         spin_lock(&info->unused_bgs_lock);
8799         while (!list_empty(&info->unused_bgs)) {
8800                 block_group = list_first_entry(&info->unused_bgs,
8801                                                struct btrfs_block_group_cache,
8802                                                bg_list);
8803                 list_del_init(&block_group->bg_list);
8804                 btrfs_put_block_group(block_group);
8805         }
8806         spin_unlock(&info->unused_bgs_lock);
8807
8808         spin_lock(&info->block_group_cache_lock);
8809         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
8810                 block_group = rb_entry(n, struct btrfs_block_group_cache,
8811                                        cache_node);
8812                 rb_erase(&block_group->cache_node,
8813                          &info->block_group_cache_tree);
8814                 RB_CLEAR_NODE(&block_group->cache_node);
8815                 spin_unlock(&info->block_group_cache_lock);
8816
8817                 down_write(&block_group->space_info->groups_sem);
8818                 list_del(&block_group->list);
8819                 up_write(&block_group->space_info->groups_sem);
8820
8821                 if (block_group->cached == BTRFS_CACHE_STARTED)
8822                         wait_block_group_cache_done(block_group);
8823
8824                 /*
8825                  * We haven't cached this block group, which means we could
8826                  * possibly have excluded extents on this block group.
8827                  */
8828                 if (block_group->cached == BTRFS_CACHE_NO ||
8829                     block_group->cached == BTRFS_CACHE_ERROR)
8830                         free_excluded_extents(info->extent_root, block_group);
8831
8832                 btrfs_remove_free_space_cache(block_group);
8833                 btrfs_put_block_group(block_group);
8834
8835                 spin_lock(&info->block_group_cache_lock);
8836         }
8837         spin_unlock(&info->block_group_cache_lock);
8838
8839         /* now that all the block groups are freed, go through and
8840          * free all the space_info structs.  This is only called during
8841          * the final stages of unmount, and so we know nobody is
8842          * using them.  We call synchronize_rcu() once before we start,
8843          * just to be on the safe side.
8844          */
8845         synchronize_rcu();
8846
8847         release_global_block_rsv(info);
8848
8849         while (!list_empty(&info->space_info)) {
8850                 int i;
8851
8852                 space_info = list_entry(info->space_info.next,
8853                                         struct btrfs_space_info,
8854                                         list);
8855                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
8856                         if (WARN_ON(space_info->bytes_pinned > 0 ||
8857                             space_info->bytes_reserved > 0 ||
8858                             space_info->bytes_may_use > 0)) {
8859                                 dump_space_info(space_info, 0, 0);
8860                         }
8861                 }
8862                 list_del(&space_info->list);
8863                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
8864                         struct kobject *kobj;
8865                         kobj = space_info->block_group_kobjs[i];
8866                         space_info->block_group_kobjs[i] = NULL;
8867                         if (kobj) {
8868                                 kobject_del(kobj);
8869                                 kobject_put(kobj);
8870                         }
8871                 }
8872                 kobject_del(&space_info->kobj);
8873                 kobject_put(&space_info->kobj);
8874         }
8875         return 0;
8876 }
8877
8878 static void __link_block_group(struct btrfs_space_info *space_info,
8879                                struct btrfs_block_group_cache *cache)
8880 {
8881         int index = get_block_group_index(cache);
8882         bool first = false;
8883
8884         down_write(&space_info->groups_sem);
8885         if (list_empty(&space_info->block_groups[index]))
8886                 first = true;
8887         list_add_tail(&cache->list, &space_info->block_groups[index]);
8888         up_write(&space_info->groups_sem);
8889
8890         if (first) {
8891                 struct raid_kobject *rkobj;
8892                 int ret;
8893
8894                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
8895                 if (!rkobj)
8896                         goto out_err;
8897                 rkobj->raid_type = index;
8898                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
8899                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
8900                                   "%s", get_raid_name(index));
8901                 if (ret) {
8902                         kobject_put(&rkobj->kobj);
8903                         goto out_err;
8904                 }
8905                 space_info->block_group_kobjs[index] = &rkobj->kobj;
8906         }
8907
8908         return;
8909 out_err:
8910         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
8911 }
8912
8913 static struct btrfs_block_group_cache *
8914 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
8915 {
8916         struct btrfs_block_group_cache *cache;
8917
8918         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8919         if (!cache)
8920                 return NULL;
8921
8922         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8923                                         GFP_NOFS);
8924         if (!cache->free_space_ctl) {
8925                 kfree(cache);
8926                 return NULL;
8927         }
8928
8929         cache->key.objectid = start;
8930         cache->key.offset = size;
8931         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8932
8933         cache->sectorsize = root->sectorsize;
8934         cache->fs_info = root->fs_info;
8935         cache->full_stripe_len = btrfs_full_stripe_len(root,
8936                                                &root->fs_info->mapping_tree,
8937                                                start);
8938         atomic_set(&cache->count, 1);
8939         spin_lock_init(&cache->lock);
8940         init_rwsem(&cache->data_rwsem);
8941         INIT_LIST_HEAD(&cache->list);
8942         INIT_LIST_HEAD(&cache->cluster_list);
8943         INIT_LIST_HEAD(&cache->bg_list);
8944         INIT_LIST_HEAD(&cache->ro_list);
8945         INIT_LIST_HEAD(&cache->dirty_list);
8946         btrfs_init_free_space_ctl(cache);
8947         atomic_set(&cache->trimming, 0);
8948
8949         return cache;
8950 }
8951
8952 int btrfs_read_block_groups(struct btrfs_root *root)
8953 {
8954         struct btrfs_path *path;
8955         int ret;
8956         struct btrfs_block_group_cache *cache;
8957         struct btrfs_fs_info *info = root->fs_info;
8958         struct btrfs_space_info *space_info;
8959         struct btrfs_key key;
8960         struct btrfs_key found_key;
8961         struct extent_buffer *leaf;
8962         int need_clear = 0;
8963         u64 cache_gen;
8964
8965         root = info->extent_root;
8966         key.objectid = 0;
8967         key.offset = 0;
8968         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8969         path = btrfs_alloc_path();
8970         if (!path)
8971                 return -ENOMEM;
8972         path->reada = 1;
8973
8974         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
8975         if (btrfs_test_opt(root, SPACE_CACHE) &&
8976             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
8977                 need_clear = 1;
8978         if (btrfs_test_opt(root, CLEAR_CACHE))
8979                 need_clear = 1;
8980
8981         while (1) {
8982                 ret = find_first_block_group(root, path, &key);
8983                 if (ret > 0)
8984                         break;
8985                 if (ret != 0)
8986                         goto error;
8987
8988                 leaf = path->nodes[0];
8989                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
8990
8991                 cache = btrfs_create_block_group_cache(root, found_key.objectid,
8992                                                        found_key.offset);
8993                 if (!cache) {
8994                         ret = -ENOMEM;
8995                         goto error;
8996                 }
8997
8998                 if (need_clear) {
8999                         /*
9000                          * When we mount with old space cache, we need to
9001                          * set BTRFS_DC_CLEAR and set dirty flag.
9002                          *
9003                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9004                          *    truncate the old free space cache inode and
9005                          *    setup a new one.
9006                          * b) Setting 'dirty flag' makes sure that we flush
9007                          *    the new space cache info onto disk.
9008                          */
9009                         if (btrfs_test_opt(root, SPACE_CACHE))
9010                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9011                 }
9012
9013                 read_extent_buffer(leaf, &cache->item,
9014                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9015                                    sizeof(cache->item));
9016                 cache->flags = btrfs_block_group_flags(&cache->item);
9017
9018                 key.objectid = found_key.objectid + found_key.offset;
9019                 btrfs_release_path(path);
9020
9021                 /*
9022                  * We need to exclude the super stripes now so that the space
9023                  * info has super bytes accounted for, otherwise we'll think
9024                  * we have more space than we actually do.
9025                  */
9026                 ret = exclude_super_stripes(root, cache);
9027                 if (ret) {
9028                         /*
9029                          * We may have excluded something, so call this just in
9030                          * case.
9031                          */
9032                         free_excluded_extents(root, cache);
9033                         btrfs_put_block_group(cache);
9034                         goto error;
9035                 }
9036
9037                 /*
9038                  * check for two cases, either we are full, and therefore
9039                  * don't need to bother with the caching work since we won't
9040                  * find any space, or we are empty, and we can just add all
9041                  * the space in and be done with it.  This saves us _alot_ of
9042                  * time, particularly in the full case.
9043                  */
9044                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
9045                         cache->last_byte_to_unpin = (u64)-1;
9046                         cache->cached = BTRFS_CACHE_FINISHED;
9047                         free_excluded_extents(root, cache);
9048                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9049                         cache->last_byte_to_unpin = (u64)-1;
9050                         cache->cached = BTRFS_CACHE_FINISHED;
9051                         add_new_free_space(cache, root->fs_info,
9052                                            found_key.objectid,
9053                                            found_key.objectid +
9054                                            found_key.offset);
9055                         free_excluded_extents(root, cache);
9056                 }
9057
9058                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
9059                 if (ret) {
9060                         btrfs_remove_free_space_cache(cache);
9061                         btrfs_put_block_group(cache);
9062                         goto error;
9063                 }
9064
9065                 ret = update_space_info(info, cache->flags, found_key.offset,
9066                                         btrfs_block_group_used(&cache->item),
9067                                         &space_info);
9068                 if (ret) {
9069                         btrfs_remove_free_space_cache(cache);
9070                         spin_lock(&info->block_group_cache_lock);
9071                         rb_erase(&cache->cache_node,
9072                                  &info->block_group_cache_tree);
9073                         RB_CLEAR_NODE(&cache->cache_node);
9074                         spin_unlock(&info->block_group_cache_lock);
9075                         btrfs_put_block_group(cache);
9076                         goto error;
9077                 }
9078
9079                 cache->space_info = space_info;
9080                 spin_lock(&cache->space_info->lock);
9081                 cache->space_info->bytes_readonly += cache->bytes_super;
9082                 spin_unlock(&cache->space_info->lock);
9083
9084                 __link_block_group(space_info, cache);
9085
9086                 set_avail_alloc_bits(root->fs_info, cache->flags);
9087                 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
9088                         set_block_group_ro(cache, 1);
9089                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9090                         spin_lock(&info->unused_bgs_lock);
9091                         /* Should always be true but just in case. */
9092                         if (list_empty(&cache->bg_list)) {
9093                                 btrfs_get_block_group(cache);
9094                                 list_add_tail(&cache->bg_list,
9095                                               &info->unused_bgs);
9096                         }
9097                         spin_unlock(&info->unused_bgs_lock);
9098                 }
9099         }
9100
9101         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
9102                 if (!(get_alloc_profile(root, space_info->flags) &
9103                       (BTRFS_BLOCK_GROUP_RAID10 |
9104                        BTRFS_BLOCK_GROUP_RAID1 |
9105                        BTRFS_BLOCK_GROUP_RAID5 |
9106                        BTRFS_BLOCK_GROUP_RAID6 |
9107                        BTRFS_BLOCK_GROUP_DUP)))
9108                         continue;
9109                 /*
9110                  * avoid allocating from un-mirrored block group if there are
9111                  * mirrored block groups.
9112                  */
9113                 list_for_each_entry(cache,
9114                                 &space_info->block_groups[BTRFS_RAID_RAID0],
9115                                 list)
9116                         set_block_group_ro(cache, 1);
9117                 list_for_each_entry(cache,
9118                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
9119                                 list)
9120                         set_block_group_ro(cache, 1);
9121         }
9122
9123         init_global_block_rsv(info);
9124         ret = 0;
9125 error:
9126         btrfs_free_path(path);
9127         return ret;
9128 }
9129
9130 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
9131                                        struct btrfs_root *root)
9132 {
9133         struct btrfs_block_group_cache *block_group, *tmp;
9134         struct btrfs_root *extent_root = root->fs_info->extent_root;
9135         struct btrfs_block_group_item item;
9136         struct btrfs_key key;
9137         int ret = 0;
9138
9139         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
9140                 if (ret)
9141                         goto next;
9142
9143                 spin_lock(&block_group->lock);
9144                 memcpy(&item, &block_group->item, sizeof(item));
9145                 memcpy(&key, &block_group->key, sizeof(key));
9146                 spin_unlock(&block_group->lock);
9147
9148                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
9149                                         sizeof(item));
9150                 if (ret)
9151                         btrfs_abort_transaction(trans, extent_root, ret);
9152                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
9153                                                key.objectid, key.offset);
9154                 if (ret)
9155                         btrfs_abort_transaction(trans, extent_root, ret);
9156 next:
9157                 list_del_init(&block_group->bg_list);
9158         }
9159 }
9160
9161 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
9162                            struct btrfs_root *root, u64 bytes_used,
9163                            u64 type, u64 chunk_objectid, u64 chunk_offset,
9164                            u64 size)
9165 {
9166         int ret;
9167         struct btrfs_root *extent_root;
9168         struct btrfs_block_group_cache *cache;
9169
9170         extent_root = root->fs_info->extent_root;
9171
9172         btrfs_set_log_full_commit(root->fs_info, trans);
9173
9174         cache = btrfs_create_block_group_cache(root, chunk_offset, size);
9175         if (!cache)
9176                 return -ENOMEM;
9177
9178         btrfs_set_block_group_used(&cache->item, bytes_used);
9179         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
9180         btrfs_set_block_group_flags(&cache->item, type);
9181
9182         cache->flags = type;
9183         cache->last_byte_to_unpin = (u64)-1;
9184         cache->cached = BTRFS_CACHE_FINISHED;
9185         ret = exclude_super_stripes(root, cache);
9186         if (ret) {
9187                 /*
9188                  * We may have excluded something, so call this just in
9189                  * case.
9190                  */
9191                 free_excluded_extents(root, cache);
9192                 btrfs_put_block_group(cache);
9193                 return ret;
9194         }
9195
9196         add_new_free_space(cache, root->fs_info, chunk_offset,
9197                            chunk_offset + size);
9198
9199         free_excluded_extents(root, cache);
9200
9201         ret = btrfs_add_block_group_cache(root->fs_info, cache);
9202         if (ret) {
9203                 btrfs_remove_free_space_cache(cache);
9204                 btrfs_put_block_group(cache);
9205                 return ret;
9206         }
9207
9208         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
9209                                 &cache->space_info);
9210         if (ret) {
9211                 btrfs_remove_free_space_cache(cache);
9212                 spin_lock(&root->fs_info->block_group_cache_lock);
9213                 rb_erase(&cache->cache_node,
9214                          &root->fs_info->block_group_cache_tree);
9215                 RB_CLEAR_NODE(&cache->cache_node);
9216                 spin_unlock(&root->fs_info->block_group_cache_lock);
9217                 btrfs_put_block_group(cache);
9218                 return ret;
9219         }
9220         update_global_block_rsv(root->fs_info);
9221
9222         spin_lock(&cache->space_info->lock);
9223         cache->space_info->bytes_readonly += cache->bytes_super;
9224         spin_unlock(&cache->space_info->lock);
9225
9226         __link_block_group(cache->space_info, cache);
9227
9228         list_add_tail(&cache->bg_list, &trans->new_bgs);
9229
9230         set_avail_alloc_bits(extent_root->fs_info, type);
9231
9232         return 0;
9233 }
9234
9235 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
9236 {
9237         u64 extra_flags = chunk_to_extended(flags) &
9238                                 BTRFS_EXTENDED_PROFILE_MASK;
9239
9240         write_seqlock(&fs_info->profiles_lock);
9241         if (flags & BTRFS_BLOCK_GROUP_DATA)
9242                 fs_info->avail_data_alloc_bits &= ~extra_flags;
9243         if (flags & BTRFS_BLOCK_GROUP_METADATA)
9244                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
9245         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
9246                 fs_info->avail_system_alloc_bits &= ~extra_flags;
9247         write_sequnlock(&fs_info->profiles_lock);
9248 }
9249
9250 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
9251                              struct btrfs_root *root, u64 group_start,
9252                              struct extent_map *em)
9253 {
9254         struct btrfs_path *path;
9255         struct btrfs_block_group_cache *block_group;
9256         struct btrfs_free_cluster *cluster;
9257         struct btrfs_root *tree_root = root->fs_info->tree_root;
9258         struct btrfs_key key;
9259         struct inode *inode;
9260         struct kobject *kobj = NULL;
9261         int ret;
9262         int index;
9263         int factor;
9264         struct btrfs_caching_control *caching_ctl = NULL;
9265         bool remove_em;
9266
9267         root = root->fs_info->extent_root;
9268
9269         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
9270         BUG_ON(!block_group);
9271         BUG_ON(!block_group->ro);
9272
9273         /*
9274          * Free the reserved super bytes from this block group before
9275          * remove it.
9276          */
9277         free_excluded_extents(root, block_group);
9278
9279         memcpy(&key, &block_group->key, sizeof(key));
9280         index = get_block_group_index(block_group);
9281         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
9282                                   BTRFS_BLOCK_GROUP_RAID1 |
9283                                   BTRFS_BLOCK_GROUP_RAID10))
9284                 factor = 2;
9285         else
9286                 factor = 1;
9287
9288         /* make sure this block group isn't part of an allocation cluster */
9289         cluster = &root->fs_info->data_alloc_cluster;
9290         spin_lock(&cluster->refill_lock);
9291         btrfs_return_cluster_to_free_space(block_group, cluster);
9292         spin_unlock(&cluster->refill_lock);
9293
9294         /*
9295          * make sure this block group isn't part of a metadata
9296          * allocation cluster
9297          */
9298         cluster = &root->fs_info->meta_alloc_cluster;
9299         spin_lock(&cluster->refill_lock);
9300         btrfs_return_cluster_to_free_space(block_group, cluster);
9301         spin_unlock(&cluster->refill_lock);
9302
9303         path = btrfs_alloc_path();
9304         if (!path) {
9305                 ret = -ENOMEM;
9306                 goto out;
9307         }
9308
9309         inode = lookup_free_space_inode(tree_root, block_group, path);
9310         if (!IS_ERR(inode)) {
9311                 ret = btrfs_orphan_add(trans, inode);
9312                 if (ret) {
9313                         btrfs_add_delayed_iput(inode);
9314                         goto out;
9315                 }
9316                 clear_nlink(inode);
9317                 /* One for the block groups ref */
9318                 spin_lock(&block_group->lock);
9319                 if (block_group->iref) {
9320                         block_group->iref = 0;
9321                         block_group->inode = NULL;
9322                         spin_unlock(&block_group->lock);
9323                         iput(inode);
9324                 } else {
9325                         spin_unlock(&block_group->lock);
9326                 }
9327                 /* One for our lookup ref */
9328                 btrfs_add_delayed_iput(inode);
9329         }
9330
9331         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
9332         key.offset = block_group->key.objectid;
9333         key.type = 0;
9334
9335         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
9336         if (ret < 0)
9337                 goto out;
9338         if (ret > 0)
9339                 btrfs_release_path(path);
9340         if (ret == 0) {
9341                 ret = btrfs_del_item(trans, tree_root, path);
9342                 if (ret)
9343                         goto out;
9344                 btrfs_release_path(path);
9345         }
9346
9347         spin_lock(&root->fs_info->block_group_cache_lock);
9348         rb_erase(&block_group->cache_node,
9349                  &root->fs_info->block_group_cache_tree);
9350         RB_CLEAR_NODE(&block_group->cache_node);
9351
9352         if (root->fs_info->first_logical_byte == block_group->key.objectid)
9353                 root->fs_info->first_logical_byte = (u64)-1;
9354         spin_unlock(&root->fs_info->block_group_cache_lock);
9355
9356         down_write(&block_group->space_info->groups_sem);
9357         /*
9358          * we must use list_del_init so people can check to see if they
9359          * are still on the list after taking the semaphore
9360          */
9361         list_del_init(&block_group->list);
9362         if (list_empty(&block_group->space_info->block_groups[index])) {
9363                 kobj = block_group->space_info->block_group_kobjs[index];
9364                 block_group->space_info->block_group_kobjs[index] = NULL;
9365                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
9366         }
9367         up_write(&block_group->space_info->groups_sem);
9368         if (kobj) {
9369                 kobject_del(kobj);
9370                 kobject_put(kobj);
9371         }
9372
9373         if (block_group->has_caching_ctl)
9374                 caching_ctl = get_caching_control(block_group);
9375         if (block_group->cached == BTRFS_CACHE_STARTED)
9376                 wait_block_group_cache_done(block_group);
9377         if (block_group->has_caching_ctl) {
9378                 down_write(&root->fs_info->commit_root_sem);
9379                 if (!caching_ctl) {
9380                         struct btrfs_caching_control *ctl;
9381
9382                         list_for_each_entry(ctl,
9383                                     &root->fs_info->caching_block_groups, list)
9384                                 if (ctl->block_group == block_group) {
9385                                         caching_ctl = ctl;
9386                                         atomic_inc(&caching_ctl->count);
9387                                         break;
9388                                 }
9389                 }
9390                 if (caching_ctl)
9391                         list_del_init(&caching_ctl->list);
9392                 up_write(&root->fs_info->commit_root_sem);
9393                 if (caching_ctl) {
9394                         /* Once for the caching bgs list and once for us. */
9395                         put_caching_control(caching_ctl);
9396                         put_caching_control(caching_ctl);
9397                 }
9398         }
9399
9400         spin_lock(&trans->transaction->dirty_bgs_lock);
9401         if (!list_empty(&block_group->dirty_list)) {
9402                 list_del_init(&block_group->dirty_list);
9403                 btrfs_put_block_group(block_group);
9404         }
9405         spin_unlock(&trans->transaction->dirty_bgs_lock);
9406
9407         btrfs_remove_free_space_cache(block_group);
9408
9409         spin_lock(&block_group->space_info->lock);
9410         list_del_init(&block_group->ro_list);
9411         block_group->space_info->total_bytes -= block_group->key.offset;
9412         block_group->space_info->bytes_readonly -= block_group->key.offset;
9413         block_group->space_info->disk_total -= block_group->key.offset * factor;
9414         spin_unlock(&block_group->space_info->lock);
9415
9416         memcpy(&key, &block_group->key, sizeof(key));
9417
9418         lock_chunks(root);
9419         if (!list_empty(&em->list)) {
9420                 /* We're in the transaction->pending_chunks list. */
9421                 free_extent_map(em);
9422         }
9423         spin_lock(&block_group->lock);
9424         block_group->removed = 1;
9425         /*
9426          * At this point trimming can't start on this block group, because we
9427          * removed the block group from the tree fs_info->block_group_cache_tree
9428          * so no one can't find it anymore and even if someone already got this
9429          * block group before we removed it from the rbtree, they have already
9430          * incremented block_group->trimming - if they didn't, they won't find
9431          * any free space entries because we already removed them all when we
9432          * called btrfs_remove_free_space_cache().
9433          *
9434          * And we must not remove the extent map from the fs_info->mapping_tree
9435          * to prevent the same logical address range and physical device space
9436          * ranges from being reused for a new block group. This is because our
9437          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
9438          * completely transactionless, so while it is trimming a range the
9439          * currently running transaction might finish and a new one start,
9440          * allowing for new block groups to be created that can reuse the same
9441          * physical device locations unless we take this special care.
9442          */
9443         remove_em = (atomic_read(&block_group->trimming) == 0);
9444         /*
9445          * Make sure a trimmer task always sees the em in the pinned_chunks list
9446          * if it sees block_group->removed == 1 (needs to lock block_group->lock
9447          * before checking block_group->removed).
9448          */
9449         if (!remove_em) {
9450                 /*
9451                  * Our em might be in trans->transaction->pending_chunks which
9452                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
9453                  * and so is the fs_info->pinned_chunks list.
9454                  *
9455                  * So at this point we must be holding the chunk_mutex to avoid
9456                  * any races with chunk allocation (more specifically at
9457                  * volumes.c:contains_pending_extent()), to ensure it always
9458                  * sees the em, either in the pending_chunks list or in the
9459                  * pinned_chunks list.
9460                  */
9461                 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
9462         }
9463         spin_unlock(&block_group->lock);
9464
9465         if (remove_em) {
9466                 struct extent_map_tree *em_tree;
9467
9468                 em_tree = &root->fs_info->mapping_tree.map_tree;
9469                 write_lock(&em_tree->lock);
9470                 /*
9471                  * The em might be in the pending_chunks list, so make sure the
9472                  * chunk mutex is locked, since remove_extent_mapping() will
9473                  * delete us from that list.
9474                  */
9475                 remove_extent_mapping(em_tree, em);
9476                 write_unlock(&em_tree->lock);
9477                 /* once for the tree */
9478                 free_extent_map(em);
9479         }
9480
9481         unlock_chunks(root);
9482
9483         btrfs_put_block_group(block_group);
9484         btrfs_put_block_group(block_group);
9485
9486         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
9487         if (ret > 0)
9488                 ret = -EIO;
9489         if (ret < 0)
9490                 goto out;
9491
9492         ret = btrfs_del_item(trans, root, path);
9493 out:
9494         btrfs_free_path(path);
9495         return ret;
9496 }
9497
9498 /*
9499  * Process the unused_bgs list and remove any that don't have any allocated
9500  * space inside of them.
9501  */
9502 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
9503 {
9504         struct btrfs_block_group_cache *block_group;
9505         struct btrfs_space_info *space_info;
9506         struct btrfs_root *root = fs_info->extent_root;
9507         struct btrfs_trans_handle *trans;
9508         int ret = 0;
9509
9510         if (!fs_info->open)
9511                 return;
9512
9513         spin_lock(&fs_info->unused_bgs_lock);
9514         while (!list_empty(&fs_info->unused_bgs)) {
9515                 u64 start, end;
9516
9517                 block_group = list_first_entry(&fs_info->unused_bgs,
9518                                                struct btrfs_block_group_cache,
9519                                                bg_list);
9520                 space_info = block_group->space_info;
9521                 list_del_init(&block_group->bg_list);
9522                 if (ret || btrfs_mixed_space_info(space_info)) {
9523                         btrfs_put_block_group(block_group);
9524                         continue;
9525                 }
9526                 spin_unlock(&fs_info->unused_bgs_lock);
9527
9528                 /* Don't want to race with allocators so take the groups_sem */
9529                 down_write(&space_info->groups_sem);
9530                 spin_lock(&block_group->lock);
9531                 if (block_group->reserved ||
9532                     btrfs_block_group_used(&block_group->item) ||
9533                     block_group->ro) {
9534                         /*
9535                          * We want to bail if we made new allocations or have
9536                          * outstanding allocations in this block group.  We do
9537                          * the ro check in case balance is currently acting on
9538                          * this block group.
9539                          */
9540                         spin_unlock(&block_group->lock);
9541                         up_write(&space_info->groups_sem);
9542                         goto next;
9543                 }
9544                 spin_unlock(&block_group->lock);
9545
9546                 /* We don't want to force the issue, only flip if it's ok. */
9547                 ret = set_block_group_ro(block_group, 0);
9548                 up_write(&space_info->groups_sem);
9549                 if (ret < 0) {
9550                         ret = 0;
9551                         goto next;
9552                 }
9553
9554                 /*
9555                  * Want to do this before we do anything else so we can recover
9556                  * properly if we fail to join the transaction.
9557                  */
9558                 /* 1 for btrfs_orphan_reserve_metadata() */
9559                 trans = btrfs_start_transaction(root, 1);
9560                 if (IS_ERR(trans)) {
9561                         btrfs_set_block_group_rw(root, block_group);
9562                         ret = PTR_ERR(trans);
9563                         goto next;
9564                 }
9565
9566                 /*
9567                  * We could have pending pinned extents for this block group,
9568                  * just delete them, we don't care about them anymore.
9569                  */
9570                 start = block_group->key.objectid;
9571                 end = start + block_group->key.offset - 1;
9572                 /*
9573                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
9574                  * btrfs_finish_extent_commit(). If we are at transaction N,
9575                  * another task might be running finish_extent_commit() for the
9576                  * previous transaction N - 1, and have seen a range belonging
9577                  * to the block group in freed_extents[] before we were able to
9578                  * clear the whole block group range from freed_extents[]. This
9579                  * means that task can lookup for the block group after we
9580                  * unpinned it from freed_extents[] and removed it, leading to
9581                  * a BUG_ON() at btrfs_unpin_extent_range().
9582                  */
9583                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
9584                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
9585                                   EXTENT_DIRTY, GFP_NOFS);
9586                 if (ret) {
9587                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
9588                         btrfs_set_block_group_rw(root, block_group);
9589                         goto end_trans;
9590                 }
9591                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
9592                                   EXTENT_DIRTY, GFP_NOFS);
9593                 if (ret) {
9594                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
9595                         btrfs_set_block_group_rw(root, block_group);
9596                         goto end_trans;
9597                 }
9598                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
9599
9600                 /* Reset pinned so btrfs_put_block_group doesn't complain */
9601                 block_group->pinned = 0;
9602
9603                 /*
9604                  * Btrfs_remove_chunk will abort the transaction if things go
9605                  * horribly wrong.
9606                  */
9607                 ret = btrfs_remove_chunk(trans, root,
9608                                          block_group->key.objectid);
9609 end_trans:
9610                 btrfs_end_transaction(trans, root);
9611 next:
9612                 btrfs_put_block_group(block_group);
9613                 spin_lock(&fs_info->unused_bgs_lock);
9614         }
9615         spin_unlock(&fs_info->unused_bgs_lock);
9616 }
9617
9618 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
9619 {
9620         struct btrfs_space_info *space_info;
9621         struct btrfs_super_block *disk_super;
9622         u64 features;
9623         u64 flags;
9624         int mixed = 0;
9625         int ret;
9626
9627         disk_super = fs_info->super_copy;
9628         if (!btrfs_super_root(disk_super))
9629                 return 1;
9630
9631         features = btrfs_super_incompat_flags(disk_super);
9632         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
9633                 mixed = 1;
9634
9635         flags = BTRFS_BLOCK_GROUP_SYSTEM;
9636         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
9637         if (ret)
9638                 goto out;
9639
9640         if (mixed) {
9641                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
9642                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
9643         } else {
9644                 flags = BTRFS_BLOCK_GROUP_METADATA;
9645                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
9646                 if (ret)
9647                         goto out;
9648
9649                 flags = BTRFS_BLOCK_GROUP_DATA;
9650                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
9651         }
9652 out:
9653         return ret;
9654 }
9655
9656 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
9657 {
9658         return unpin_extent_range(root, start, end, false);
9659 }
9660
9661 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
9662 {
9663         struct btrfs_fs_info *fs_info = root->fs_info;
9664         struct btrfs_block_group_cache *cache = NULL;
9665         u64 group_trimmed;
9666         u64 start;
9667         u64 end;
9668         u64 trimmed = 0;
9669         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
9670         int ret = 0;
9671
9672         /*
9673          * try to trim all FS space, our block group may start from non-zero.
9674          */
9675         if (range->len == total_bytes)
9676                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
9677         else
9678                 cache = btrfs_lookup_block_group(fs_info, range->start);
9679
9680         while (cache) {
9681                 if (cache->key.objectid >= (range->start + range->len)) {
9682                         btrfs_put_block_group(cache);
9683                         break;
9684                 }
9685
9686                 start = max(range->start, cache->key.objectid);
9687                 end = min(range->start + range->len,
9688                                 cache->key.objectid + cache->key.offset);
9689
9690                 if (end - start >= range->minlen) {
9691                         if (!block_group_cache_done(cache)) {
9692                                 ret = cache_block_group(cache, 0);
9693                                 if (ret) {
9694                                         btrfs_put_block_group(cache);
9695                                         break;
9696                                 }
9697                                 ret = wait_block_group_cache_done(cache);
9698                                 if (ret) {
9699                                         btrfs_put_block_group(cache);
9700                                         break;
9701                                 }
9702                         }
9703                         ret = btrfs_trim_block_group(cache,
9704                                                      &group_trimmed,
9705                                                      start,
9706                                                      end,
9707                                                      range->minlen);
9708
9709                         trimmed += group_trimmed;
9710                         if (ret) {
9711                                 btrfs_put_block_group(cache);
9712                                 break;
9713                         }
9714                 }
9715
9716                 cache = next_block_group(fs_info->tree_root, cache);
9717         }
9718
9719         range->len = trimmed;
9720         return ret;
9721 }
9722
9723 /*
9724  * btrfs_{start,end}_write_no_snapshoting() are similar to
9725  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
9726  * data into the page cache through nocow before the subvolume is snapshoted,
9727  * but flush the data into disk after the snapshot creation, or to prevent
9728  * operations while snapshoting is ongoing and that cause the snapshot to be
9729  * inconsistent (writes followed by expanding truncates for example).
9730  */
9731 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
9732 {
9733         percpu_counter_dec(&root->subv_writers->counter);
9734         /*
9735          * Make sure counter is updated before we wake up
9736          * waiters.
9737          */
9738         smp_mb();
9739         if (waitqueue_active(&root->subv_writers->wait))
9740                 wake_up(&root->subv_writers->wait);
9741 }
9742
9743 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
9744 {
9745         if (atomic_read(&root->will_be_snapshoted))
9746                 return 0;
9747
9748         percpu_counter_inc(&root->subv_writers->counter);
9749         /*
9750          * Make sure counter is updated before we check for snapshot creation.
9751          */
9752         smp_mb();
9753         if (atomic_read(&root->will_be_snapshoted)) {
9754                 btrfs_end_write_no_snapshoting(root);
9755                 return 0;
9756         }
9757         return 1;
9758 }