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 "compat.h"
  28 #include "hash.h"
  29 #include "ctree.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "transaction.h"
  33 #include "volumes.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36
  37 /* control flags for do_chunk_alloc's force field
  38  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  39  * if we really need one.
  40  *
  41  * CHUNK_ALLOC_FORCE means it must try to allocate one
  42  *
  43  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  44  * if we have very few chunks already allocated.  This is
  45  * used as part of the clustering code to help make sure
  46  * we have a good pool of storage to cluster in, without
  47  * filling the FS with empty chunks
  48  *
  49  */
  50 enum {
  51         CHUNK_ALLOC_NO_FORCE = 0,
  52         CHUNK_ALLOC_FORCE = 1,
  53         CHUNK_ALLOC_LIMITED = 2,
  54 };
  55
  56 /*
  57  * Control how reservations are dealt with.
  58  *
  59  * RESERVE_FREE - freeing a reservation.
  60  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  61  *   ENOSPC accounting
  62  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  63  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  64  */
  65 enum {
  66         RESERVE_FREE = 0,
  67         RESERVE_ALLOC = 1,
  68         RESERVE_ALLOC_NO_ACCOUNT = 2,
  69 };
  70
  71 static int update_block_group(struct btrfs_trans_handle *trans,
  72                               struct btrfs_root *root,
  73                               u64 bytenr, u64 num_bytes, int alloc);
  74 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  75                                 struct btrfs_root *root,
  76                                 u64 bytenr, u64 num_bytes, u64 parent,
  77                                 u64 root_objectid, u64 owner_objectid,
  78                                 u64 owner_offset, int refs_to_drop,
  79                                 struct btrfs_delayed_extent_op *extra_op);
  80 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  81                                     struct extent_buffer *leaf,
  82                                     struct btrfs_extent_item *ei);
  83 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  84                                       struct btrfs_root *root,
  85                                       u64 parent, u64 root_objectid,
  86                                       u64 flags, u64 owner, u64 offset,
  87                                       struct btrfs_key *ins, int ref_mod);
  88 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  89                                      struct btrfs_root *root,
  90                                      u64 parent, u64 root_objectid,
  91                                      u64 flags, struct btrfs_disk_key *key,
  92                                      int level, struct btrfs_key *ins);
  93 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  94                           struct btrfs_root *extent_root, u64 alloc_bytes,
  95                           u64 flags, int force);
  96 static int find_next_key(struct btrfs_path *path, int level,
  97                          struct btrfs_key *key);
  98 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
  99                             int dump_block_groups);
 100 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 101                                        u64 num_bytes, int reserve);
 102
 103 static noinline int
 104 block_group_cache_done(struct btrfs_block_group_cache *cache)
 105 {
 106         smp_mb();
 107         return cache->cached == BTRFS_CACHE_FINISHED;
 108 }
 109
 110 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 111 {
 112         return (cache->flags & bits) == bits;
 113 }
 114
 115 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 116 {
 117         atomic_inc(&cache->count);
 118 }
 119
 120 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 121 {
 122         if (atomic_dec_and_test(&cache->count)) {
 123                 WARN_ON(cache->pinned > 0);
 124                 WARN_ON(cache->reserved > 0);
 125                 kfree(cache->free_space_ctl);
 126                 kfree(cache);
 127         }
 128 }
 129
 130 /*
 131  * this adds the block group to the fs_info rb tree for the block group
 132  * cache
 133  */
 134 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 135                                 struct btrfs_block_group_cache *block_group)
 136 {
 137         struct rb_node **p;
 138         struct rb_node *parent = NULL;
 139         struct btrfs_block_group_cache *cache;
 140
 141         spin_lock(&info->block_group_cache_lock);
 142         p = &info->block_group_cache_tree.rb_node;
 143
 144         while (*p) {
 145                 parent = *p;
 146                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 147                                  cache_node);
 148                 if (block_group->key.objectid < cache->key.objectid) {
 149                         p = &(*p)->rb_left;
 150                 } else if (block_group->key.objectid > cache->key.objectid) {
 151                         p = &(*p)->rb_right;
 152                 } else {
 153                         spin_unlock(&info->block_group_cache_lock);
 154                         return -EEXIST;
 155                 }
 156         }
 157
 158         rb_link_node(&block_group->cache_node, parent, p);
 159         rb_insert_color(&block_group->cache_node,
 160                         &info->block_group_cache_tree);
 161         spin_unlock(&info->block_group_cache_lock);
 162
 163         return 0;
 164 }
 165
 166 /*
 167  * This will return the block group at or after bytenr if contains is 0, else
 168  * it will return the block group that contains the bytenr
 169  */
 170 static struct btrfs_block_group_cache *
 171 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 172                               int contains)
 173 {
 174         struct btrfs_block_group_cache *cache, *ret = NULL;
 175         struct rb_node *n;
 176         u64 end, start;
 177
 178         spin_lock(&info->block_group_cache_lock);
 179         n = info->block_group_cache_tree.rb_node;
 180
 181         while (n) {
 182                 cache = rb_entry(n, struct btrfs_block_group_cache,
 183                                  cache_node);
 184                 end = cache->key.objectid + cache->key.offset - 1;
 185                 start = cache->key.objectid;
 186
 187                 if (bytenr < start) {
 188                         if (!contains && (!ret || start < ret->key.objectid))
 189                                 ret = cache;
 190                         n = n->rb_left;
 191                 } else if (bytenr > start) {
 192                         if (contains && bytenr <= end) {
 193                                 ret = cache;
 194                                 break;
 195                         }
 196                         n = n->rb_right;
 197                 } else {
 198                         ret = cache;
 199                         break;
 200                 }
 201         }
 202         if (ret)
 203                 btrfs_get_block_group(ret);
 204         spin_unlock(&info->block_group_cache_lock);
 205
 206         return ret;
 207 }
 208
 209 static int add_excluded_extent(struct btrfs_root *root,
 210                                u64 start, u64 num_bytes)
 211 {
 212         u64 end = start + num_bytes - 1;
 213         set_extent_bits(&root->fs_info->freed_extents[0],
 214                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 215         set_extent_bits(&root->fs_info->freed_extents[1],
 216                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 217         return 0;
 218 }
 219
 220 static void free_excluded_extents(struct btrfs_root *root,
 221                                   struct btrfs_block_group_cache *cache)
 222 {
 223         u64 start, end;
 224
 225         start = cache->key.objectid;
 226         end = start + cache->key.offset - 1;
 227
 228         clear_extent_bits(&root->fs_info->freed_extents[0],
 229                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 230         clear_extent_bits(&root->fs_info->freed_extents[1],
 231                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 232 }
 233
 234 static int exclude_super_stripes(struct btrfs_root *root,
 235                                  struct btrfs_block_group_cache *cache)
 236 {
 237         u64 bytenr;
 238         u64 *logical;
 239         int stripe_len;
 240         int i, nr, ret;
 241
 242         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 243                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 244                 cache->bytes_super += stripe_len;
 245                 ret = add_excluded_extent(root, cache->key.objectid,
 246                                           stripe_len);
 247                 BUG_ON(ret);
 248         }
 249
 250         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 251                 bytenr = btrfs_sb_offset(i);
 252                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 253                                        cache->key.objectid, bytenr,
 254                                        0, &logical, &nr, &stripe_len);
 255                 BUG_ON(ret);
 256
 257                 while (nr--) {
 258                         cache->bytes_super += stripe_len;
 259                         ret = add_excluded_extent(root, logical[nr],
 260                                                   stripe_len);
 261                         BUG_ON(ret);
 262                 }
 263
 264                 kfree(logical);
 265         }
 266         return 0;
 267 }
 268
 269 static struct btrfs_caching_control *
 270 get_caching_control(struct btrfs_block_group_cache *cache)
 271 {
 272         struct btrfs_caching_control *ctl;
 273
 274         spin_lock(&cache->lock);
 275         if (cache->cached != BTRFS_CACHE_STARTED) {
 276                 spin_unlock(&cache->lock);
 277                 return NULL;
 278         }
 279
 280         /* We're loading it the fast way, so we don't have a caching_ctl. */
 281         if (!cache->caching_ctl) {
 282                 spin_unlock(&cache->lock);
 283                 return NULL;
 284         }
 285
 286         ctl = cache->caching_ctl;
 287         atomic_inc(&ctl->count);
 288         spin_unlock(&cache->lock);
 289         return ctl;
 290 }
 291
 292 static void put_caching_control(struct btrfs_caching_control *ctl)
 293 {
 294         if (atomic_dec_and_test(&ctl->count))
 295                 kfree(ctl);
 296 }
 297
 298 /*
 299  * this is only called by cache_block_group, since we could have freed extents
 300  * we need to check the pinned_extents for any extents that can't be used yet
 301  * since their free space will be released as soon as the transaction commits.
 302  */
 303 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 304                               struct btrfs_fs_info *info, u64 start, u64 end)
 305 {
 306         u64 extent_start, extent_end, size, total_added = 0;
 307         int ret;
 308
 309         while (start < end) {
 310                 ret = find_first_extent_bit(info->pinned_extents, start,
 311                                             &extent_start, &extent_end,
 312                                             EXTENT_DIRTY | EXTENT_UPTODATE);
 313                 if (ret)
 314                         break;
 315
 316                 if (extent_start <= start) {
 317                         start = extent_end + 1;
 318                 } else if (extent_start > start && extent_start < end) {
 319                         size = extent_start - start;
 320                         total_added += size;
 321                         ret = btrfs_add_free_space(block_group, start,
 322                                                    size);
 323                         BUG_ON(ret);
 324                         start = extent_end + 1;
 325                 } else {
 326                         break;
 327                 }
 328         }
 329
 330         if (start < end) {
 331                 size = end - start;
 332                 total_added += size;
 333                 ret = btrfs_add_free_space(block_group, start, size);
 334                 BUG_ON(ret);
 335         }
 336
 337         return total_added;
 338 }
 339
 340 static noinline void caching_thread(struct btrfs_work *work)
 341 {
 342         struct btrfs_block_group_cache *block_group;
 343         struct btrfs_fs_info *fs_info;
 344         struct btrfs_caching_control *caching_ctl;
 345         struct btrfs_root *extent_root;
 346         struct btrfs_path *path;
 347         struct extent_buffer *leaf;
 348         struct btrfs_key key;
 349         u64 total_found = 0;
 350         u64 last = 0;
 351         u32 nritems;
 352         int ret = 0;
 353
 354         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 355         block_group = caching_ctl->block_group;
 356         fs_info = block_group->fs_info;
 357         extent_root = fs_info->extent_root;
 358
 359         path = btrfs_alloc_path();
 360         if (!path)
 361                 goto out;
 362
 363         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 364
 365         /*
 366          * We don't want to deadlock with somebody trying to allocate a new
 367          * extent for the extent root while also trying to search the extent
 368          * root to add free space.  So we skip locking and search the commit
 369          * root, since its read-only
 370          */
 371         path->skip_locking = 1;
 372         path->search_commit_root = 1;
 373         path->reada = 1;
 374
 375         key.objectid = last;
 376         key.offset = 0;
 377         key.type = BTRFS_EXTENT_ITEM_KEY;
 378 again:
 379         mutex_lock(&caching_ctl->mutex);
 380         /* need to make sure the commit_root doesn't disappear */
 381         down_read(&fs_info->extent_commit_sem);
 382
 383         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 384         if (ret < 0)
 385                 goto err;
 386
 387         leaf = path->nodes[0];
 388         nritems = btrfs_header_nritems(leaf);
 389
 390         while (1) {
 391                 if (btrfs_fs_closing(fs_info) > 1) {
 392                         last = (u64)-1;
 393                         break;
 394                 }
 395
 396                 if (path->slots[0] < nritems) {
 397                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 398                 } else {
 399                         ret = find_next_key(path, 0, &key);
 400                         if (ret)
 401                                 break;
 402
 403                         if (need_resched() ||
 404                             btrfs_next_leaf(extent_root, path)) {
 405                                 caching_ctl->progress = last;
 406                                 btrfs_release_path(path);
 407                                 up_read(&fs_info->extent_commit_sem);
 408                                 mutex_unlock(&caching_ctl->mutex);
 409                                 cond_resched();
 410                                 goto again;
 411                         }
 412                         leaf = path->nodes[0];
 413                         nritems = btrfs_header_nritems(leaf);
 414                         continue;
 415                 }
 416
 417                 if (key.objectid < block_group->key.objectid) {
 418                         path->slots[0]++;
 419                         continue;
 420                 }
 421
 422                 if (key.objectid >= block_group->key.objectid +
 423                     block_group->key.offset)
 424                         break;
 425
 426                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 427                         total_found += add_new_free_space(block_group,
 428                                                           fs_info, last,
 429                                                           key.objectid);
 430                         last = key.objectid + key.offset;
 431
 432                         if (total_found > (1024 * 1024 * 2)) {
 433                                 total_found = 0;
 434                                 wake_up(&caching_ctl->wait);
 435                         }
 436                 }
 437                 path->slots[0]++;
 438         }
 439         ret = 0;
 440
 441         total_found += add_new_free_space(block_group, fs_info, last,
 442                                           block_group->key.objectid +
 443                                           block_group->key.offset);
 444         caching_ctl->progress = (u64)-1;
 445
 446         spin_lock(&block_group->lock);
 447         block_group->caching_ctl = NULL;
 448         block_group->cached = BTRFS_CACHE_FINISHED;
 449         spin_unlock(&block_group->lock);
 450
 451 err:
 452         btrfs_free_path(path);
 453         up_read(&fs_info->extent_commit_sem);
 454
 455         free_excluded_extents(extent_root, block_group);
 456
 457         mutex_unlock(&caching_ctl->mutex);
 458 out:
 459         wake_up(&caching_ctl->wait);
 460
 461         put_caching_control(caching_ctl);
 462         btrfs_put_block_group(block_group);
 463 }
 464
 465 static int cache_block_group(struct btrfs_block_group_cache *cache,
 466                              struct btrfs_trans_handle *trans,
 467                              struct btrfs_root *root,
 468                              int load_cache_only)
 469 {
 470         DEFINE_WAIT(wait);
 471         struct btrfs_fs_info *fs_info = cache->fs_info;
 472         struct btrfs_caching_control *caching_ctl;
 473         int ret = 0;
 474
 475         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 476         BUG_ON(!caching_ctl);
 477
 478         INIT_LIST_HEAD(&caching_ctl->list);
 479         mutex_init(&caching_ctl->mutex);
 480         init_waitqueue_head(&caching_ctl->wait);
 481         caching_ctl->block_group = cache;
 482         caching_ctl->progress = cache->key.objectid;
 483         atomic_set(&caching_ctl->count, 1);
 484         caching_ctl->work.func = caching_thread;
 485
 486         spin_lock(&cache->lock);
 487         /*
 488          * This should be a rare occasion, but this could happen I think in the
 489          * case where one thread starts to load the space cache info, and then
 490          * some other thread starts a transaction commit which tries to do an
 491          * allocation while the other thread is still loading the space cache
 492          * info.  The previous loop should have kept us from choosing this block
 493          * group, but if we've moved to the state where we will wait on caching
 494          * block groups we need to first check if we're doing a fast load here,
 495          * so we can wait for it to finish, otherwise we could end up allocating
 496          * from a block group who's cache gets evicted for one reason or
 497          * another.
 498          */
 499         while (cache->cached == BTRFS_CACHE_FAST) {
 500                 struct btrfs_caching_control *ctl;
 501
 502                 ctl = cache->caching_ctl;
 503                 atomic_inc(&ctl->count);
 504                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 505                 spin_unlock(&cache->lock);
 506
 507                 schedule();
 508
 509                 finish_wait(&ctl->wait, &wait);
 510                 put_caching_control(ctl);
 511                 spin_lock(&cache->lock);
 512         }
 513
 514         if (cache->cached != BTRFS_CACHE_NO) {
 515                 spin_unlock(&cache->lock);
 516                 kfree(caching_ctl);
 517                 return 0;
 518         }
 519         WARN_ON(cache->caching_ctl);
 520         cache->caching_ctl = caching_ctl;
 521         cache->cached = BTRFS_CACHE_FAST;
 522         spin_unlock(&cache->lock);
 523
 524         /*
 525          * We can't do the read from on-disk cache during a commit since we need
 526          * to have the normal tree locking.  Also if we are currently trying to
 527          * allocate blocks for the tree root we can't do the fast caching since
 528          * we likely hold important locks.
 529          */
 530         if (trans && (!trans->transaction->in_commit) &&
 531             (root && root != root->fs_info->tree_root) &&
 532             btrfs_test_opt(root, SPACE_CACHE)) {
 533                 ret = load_free_space_cache(fs_info, cache);
 534
 535                 spin_lock(&cache->lock);
 536                 if (ret == 1) {
 537                         cache->caching_ctl = NULL;
 538                         cache->cached = BTRFS_CACHE_FINISHED;
 539                         cache->last_byte_to_unpin = (u64)-1;
 540                 } else {
 541                         if (load_cache_only) {
 542                                 cache->caching_ctl = NULL;
 543                                 cache->cached = BTRFS_CACHE_NO;
 544                         } else {
 545                                 cache->cached = BTRFS_CACHE_STARTED;
 546                         }
 547                 }
 548                 spin_unlock(&cache->lock);
 549                 wake_up(&caching_ctl->wait);
 550                 if (ret == 1) {
 551                         put_caching_control(caching_ctl);
 552                         free_excluded_extents(fs_info->extent_root, cache);
 553                         return 0;
 554                 }
 555         } else {
 556                 /*
 557                  * We are not going to do the fast caching, set cached to the
 558                  * appropriate value and wakeup any waiters.
 559                  */
 560                 spin_lock(&cache->lock);
 561                 if (load_cache_only) {
 562                         cache->caching_ctl = NULL;
 563                         cache->cached = BTRFS_CACHE_NO;
 564                 } else {
 565                         cache->cached = BTRFS_CACHE_STARTED;
 566                 }
 567                 spin_unlock(&cache->lock);
 568                 wake_up(&caching_ctl->wait);
 569         }
 570
 571         if (load_cache_only) {
 572                 put_caching_control(caching_ctl);
 573                 return 0;
 574         }
 575
 576         down_write(&fs_info->extent_commit_sem);
 577         atomic_inc(&caching_ctl->count);
 578         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 579         up_write(&fs_info->extent_commit_sem);
 580
 581         btrfs_get_block_group(cache);
 582
 583         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 584
 585         return ret;
 586 }
 587
 588 /*
 589  * return the block group that starts at or after bytenr
 590  */
 591 static struct btrfs_block_group_cache *
 592 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 593 {
 594         struct btrfs_block_group_cache *cache;
 595
 596         cache = block_group_cache_tree_search(info, bytenr, 0);
 597
 598         return cache;
 599 }
 600
 601 /*
 602  * return the block group that contains the given bytenr
 603  */
 604 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 605                                                  struct btrfs_fs_info *info,
 606                                                  u64 bytenr)
 607 {
 608         struct btrfs_block_group_cache *cache;
 609
 610         cache = block_group_cache_tree_search(info, bytenr, 1);
 611
 612         return cache;
 613 }
 614
 615 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 616                                                   u64 flags)
 617 {
 618         struct list_head *head = &info->space_info;
 619         struct btrfs_space_info *found;
 620
 621         flags &= BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_SYSTEM |
 622                  BTRFS_BLOCK_GROUP_METADATA;
 623
 624         rcu_read_lock();
 625         list_for_each_entry_rcu(found, head, list) {
 626                 if (found->flags & flags) {
 627                         rcu_read_unlock();
 628                         return found;
 629                 }
 630         }
 631         rcu_read_unlock();
 632         return NULL;
 633 }
 634
 635 /*
 636  * after adding space to the filesystem, we need to clear the full flags
 637  * on all the space infos.
 638  */
 639 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 640 {
 641         struct list_head *head = &info->space_info;
 642         struct btrfs_space_info *found;
 643
 644         rcu_read_lock();
 645         list_for_each_entry_rcu(found, head, list)
 646                 found->full = 0;
 647         rcu_read_unlock();
 648 }
 649
 650 static u64 div_factor(u64 num, int factor)
 651 {
 652         if (factor == 10)
 653                 return num;
 654         num *= factor;
 655         do_div(num, 10);
 656         return num;
 657 }
 658
 659 static u64 div_factor_fine(u64 num, int factor)
 660 {
 661         if (factor == 100)
 662                 return num;
 663         num *= factor;
 664         do_div(num, 100);
 665         return num;
 666 }
 667
 668 u64 btrfs_find_block_group(struct btrfs_root *root,
 669                            u64 search_start, u64 search_hint, int owner)
 670 {
 671         struct btrfs_block_group_cache *cache;
 672         u64 used;
 673         u64 last = max(search_hint, search_start);
 674         u64 group_start = 0;
 675         int full_search = 0;
 676         int factor = 9;
 677         int wrapped = 0;
 678 again:
 679         while (1) {
 680                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 681                 if (!cache)
 682                         break;
 683
 684                 spin_lock(&cache->lock);
 685                 last = cache->key.objectid + cache->key.offset;
 686                 used = btrfs_block_group_used(&cache->item);
 687
 688                 if ((full_search || !cache->ro) &&
 689                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 690                         if (used + cache->pinned + cache->reserved <
 691                             div_factor(cache->key.offset, factor)) {
 692                                 group_start = cache->key.objectid;
 693                                 spin_unlock(&cache->lock);
 694                                 btrfs_put_block_group(cache);
 695                                 goto found;
 696                         }
 697                 }
 698                 spin_unlock(&cache->lock);
 699                 btrfs_put_block_group(cache);
 700                 cond_resched();
 701         }
 702         if (!wrapped) {
 703                 last = search_start;
 704                 wrapped = 1;
 705                 goto again;
 706         }
 707         if (!full_search && factor < 10) {
 708                 last = search_start;
 709                 full_search = 1;
 710                 factor = 10;
 711                 goto again;
 712         }
 713 found:
 714         return group_start;
 715 }
 716
 717 /* simple helper to search for an existing extent at a given offset */
 718 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 719 {
 720         int ret;
 721         struct btrfs_key key;
 722         struct btrfs_path *path;
 723
 724         path = btrfs_alloc_path();
 725         if (!path)
 726                 return -ENOMEM;
 727
 728         key.objectid = start;
 729         key.offset = len;
 730         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 731         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 732                                 0, 0);
 733         btrfs_free_path(path);
 734         return ret;
 735 }
 736
 737 /*
 738  * helper function to lookup reference count and flags of extent.
 739  *
 740  * the head node for delayed ref is used to store the sum of all the
 741  * reference count modifications queued up in the rbtree. the head
 742  * node may also store the extent flags to set. This way you can check
 743  * to see what the reference count and extent flags would be if all of
 744  * the delayed refs are not processed.
 745  */
 746 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 747                              struct btrfs_root *root, u64 bytenr,
 748                              u64 num_bytes, u64 *refs, u64 *flags)
 749 {
 750         struct btrfs_delayed_ref_head *head;
 751         struct btrfs_delayed_ref_root *delayed_refs;
 752         struct btrfs_path *path;
 753         struct btrfs_extent_item *ei;
 754         struct extent_buffer *leaf;
 755         struct btrfs_key key;
 756         u32 item_size;
 757         u64 num_refs;
 758         u64 extent_flags;
 759         int ret;
 760
 761         path = btrfs_alloc_path();
 762         if (!path)
 763                 return -ENOMEM;
 764
 765         key.objectid = bytenr;
 766         key.type = BTRFS_EXTENT_ITEM_KEY;
 767         key.offset = num_bytes;
 768         if (!trans) {
 769                 path->skip_locking = 1;
 770                 path->search_commit_root = 1;
 771         }
 772 again:
 773         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 774                                 &key, path, 0, 0);
 775         if (ret < 0)
 776                 goto out_free;
 777
 778         if (ret == 0) {
 779                 leaf = path->nodes[0];
 780                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 781                 if (item_size >= sizeof(*ei)) {
 782                         ei = btrfs_item_ptr(leaf, path->slots[0],
 783                                             struct btrfs_extent_item);
 784                         num_refs = btrfs_extent_refs(leaf, ei);
 785                         extent_flags = btrfs_extent_flags(leaf, ei);
 786                 } else {
 787 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 788                         struct btrfs_extent_item_v0 *ei0;
 789                         BUG_ON(item_size != sizeof(*ei0));
 790                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 791                                              struct btrfs_extent_item_v0);
 792                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 793                         /* FIXME: this isn't correct for data */
 794                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 795 #else
 796                         BUG();
 797 #endif
 798                 }
 799                 BUG_ON(num_refs == 0);
 800         } else {
 801                 num_refs = 0;
 802                 extent_flags = 0;
 803                 ret = 0;
 804         }
 805
 806         if (!trans)
 807                 goto out;
 808
 809         delayed_refs = &trans->transaction->delayed_refs;
 810         spin_lock(&delayed_refs->lock);
 811         head = btrfs_find_delayed_ref_head(trans, bytenr);
 812         if (head) {
 813                 if (!mutex_trylock(&head->mutex)) {
 814                         atomic_inc(&head->node.refs);
 815                         spin_unlock(&delayed_refs->lock);
 816
 817                         btrfs_release_path(path);
 818
 819                         /*
 820                          * Mutex was contended, block until it's released and try
 821                          * again
 822                          */
 823                         mutex_lock(&head->mutex);
 824                         mutex_unlock(&head->mutex);
 825                         btrfs_put_delayed_ref(&head->node);
 826                         goto again;
 827                 }
 828                 if (head->extent_op && head->extent_op->update_flags)
 829                         extent_flags |= head->extent_op->flags_to_set;
 830                 else
 831                         BUG_ON(num_refs == 0);
 832
 833                 num_refs += head->node.ref_mod;
 834                 mutex_unlock(&head->mutex);
 835         }
 836         spin_unlock(&delayed_refs->lock);
 837 out:
 838         WARN_ON(num_refs == 0);
 839         if (refs)
 840                 *refs = num_refs;
 841         if (flags)
 842                 *flags = extent_flags;
 843 out_free:
 844         btrfs_free_path(path);
 845         return ret;
 846 }
 847
 848 /*
 849  * Back reference rules.  Back refs have three main goals:
 850  *
 851  * 1) differentiate between all holders of references to an extent so that
 852  *    when a reference is dropped we can make sure it was a valid reference
 853  *    before freeing the extent.
 854  *
 855  * 2) Provide enough information to quickly find the holders of an extent
 856  *    if we notice a given block is corrupted or bad.
 857  *
 858  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 859  *    maintenance.  This is actually the same as #2, but with a slightly
 860  *    different use case.
 861  *
 862  * There are two kinds of back refs. The implicit back refs is optimized
 863  * for pointers in non-shared tree blocks. For a given pointer in a block,
 864  * back refs of this kind provide information about the block's owner tree
 865  * and the pointer's key. These information allow us to find the block by
 866  * b-tree searching. The full back refs is for pointers in tree blocks not
 867  * referenced by their owner trees. The location of tree block is recorded
 868  * in the back refs. Actually the full back refs is generic, and can be
 869  * used in all cases the implicit back refs is used. The major shortcoming
 870  * of the full back refs is its overhead. Every time a tree block gets
 871  * COWed, we have to update back refs entry for all pointers in it.
 872  *
 873  * For a newly allocated tree block, we use implicit back refs for
 874  * pointers in it. This means most tree related operations only involve
 875  * implicit back refs. For a tree block created in old transaction, the
 876  * only way to drop a reference to it is COW it. So we can detect the
 877  * event that tree block loses its owner tree's reference and do the
 878  * back refs conversion.
 879  *
 880  * When a tree block is COW'd through a tree, there are four cases:
 881  *
 882  * The reference count of the block is one and the tree is the block's
 883  * owner tree. Nothing to do in this case.
 884  *
 885  * The reference count of the block is one and the tree is not the
 886  * block's owner tree. In this case, full back refs is used for pointers
 887  * in the block. Remove these full back refs, add implicit back refs for
 888  * every pointers in the new block.
 889  *
 890  * The reference count of the block is greater than one and the tree is
 891  * the block's owner tree. In this case, implicit back refs is used for
 892  * pointers in the block. Add full back refs for every pointers in the
 893  * block, increase lower level extents' reference counts. The original
 894  * implicit back refs are entailed to the new block.
 895  *
 896  * The reference count of the block is greater than one and the tree is
 897  * not the block's owner tree. Add implicit back refs for every pointer in
 898  * the new block, increase lower level extents' reference count.
 899  *
 900  * Back Reference Key composing:
 901  *
 902  * The key objectid corresponds to the first byte in the extent,
 903  * The key type is used to differentiate between types of back refs.
 904  * There are different meanings of the key offset for different types
 905  * of back refs.
 906  *
 907  * File extents can be referenced by:
 908  *
 909  * - multiple snapshots, subvolumes, or different generations in one subvol
 910  * - different files inside a single subvolume
 911  * - different offsets inside a file (bookend extents in file.c)
 912  *
 913  * The extent ref structure for the implicit back refs has fields for:
 914  *
 915  * - Objectid of the subvolume root
 916  * - objectid of the file holding the reference
 917  * - original offset in the file
 918  * - how many bookend extents
 919  *
 920  * The key offset for the implicit back refs is hash of the first
 921  * three fields.
 922  *
 923  * The extent ref structure for the full back refs has field for:
 924  *
 925  * - number of pointers in the tree leaf
 926  *
 927  * The key offset for the implicit back refs is the first byte of
 928  * the tree leaf
 929  *
 930  * When a file extent is allocated, The implicit back refs is used.
 931  * the fields are filled in:
 932  *
 933  *     (root_key.objectid, inode objectid, offset in file, 1)
 934  *
 935  * When a file extent is removed file truncation, we find the
 936  * corresponding implicit back refs and check the following fields:
 937  *
 938  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 939  *
 940  * Btree extents can be referenced by:
 941  *
 942  * - Different subvolumes
 943  *
 944  * Both the implicit back refs and the full back refs for tree blocks
 945  * only consist of key. The key offset for the implicit back refs is
 946  * objectid of block's owner tree. The key offset for the full back refs
 947  * is the first byte of parent block.
 948  *
 949  * When implicit back refs is used, information about the lowest key and
 950  * level of the tree block are required. These information are stored in
 951  * tree block info structure.
 952  */
 953
 954 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 955 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 956                                   struct btrfs_root *root,
 957                                   struct btrfs_path *path,
 958                                   u64 owner, u32 extra_size)
 959 {
 960         struct btrfs_extent_item *item;
 961         struct btrfs_extent_item_v0 *ei0;
 962         struct btrfs_extent_ref_v0 *ref0;
 963         struct btrfs_tree_block_info *bi;
 964         struct extent_buffer *leaf;
 965         struct btrfs_key key;
 966         struct btrfs_key found_key;
 967         u32 new_size = sizeof(*item);
 968         u64 refs;
 969         int ret;
 970
 971         leaf = path->nodes[0];
 972         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 973
 974         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 975         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 976                              struct btrfs_extent_item_v0);
 977         refs = btrfs_extent_refs_v0(leaf, ei0);
 978
 979         if (owner == (u64)-1) {
 980                 while (1) {
 981                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 982                                 ret = btrfs_next_leaf(root, path);
 983                                 if (ret < 0)
 984                                         return ret;
 985                                 BUG_ON(ret > 0);
 986                                 leaf = path->nodes[0];
 987                         }
 988                         btrfs_item_key_to_cpu(leaf, &found_key,
 989                                               path->slots[0]);
 990                         BUG_ON(key.objectid != found_key.objectid);
 991                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 992                                 path->slots[0]++;
 993                                 continue;
 994                         }
 995                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 996                                               struct btrfs_extent_ref_v0);
 997                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 998                         break;
 999                 }
1000         }
1001         btrfs_release_path(path);
1002
1003         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1004                 new_size += sizeof(*bi);
1005
1006         new_size -= sizeof(*ei0);
1007         ret = btrfs_search_slot(trans, root, &key, path,
1008                                 new_size + extra_size, 1);
1009         if (ret < 0)
1010                 return ret;
1011         BUG_ON(ret);
1012
1013         ret = btrfs_extend_item(trans, root, path, new_size);
1014
1015         leaf = path->nodes[0];
1016         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1017         btrfs_set_extent_refs(leaf, item, refs);
1018         /* FIXME: get real generation */
1019         btrfs_set_extent_generation(leaf, item, 0);
1020         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1021                 btrfs_set_extent_flags(leaf, item,
1022                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1023                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1024                 bi = (struct btrfs_tree_block_info *)(item + 1);
1025                 /* FIXME: get first key of the block */
1026                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1027                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1028         } else {
1029                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1030         }
1031         btrfs_mark_buffer_dirty(leaf);
1032         return 0;
1033 }
1034 #endif
1035
1036 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1037 {
1038         u32 high_crc = ~(u32)0;
1039         u32 low_crc = ~(u32)0;
1040         __le64 lenum;
1041
1042         lenum = cpu_to_le64(root_objectid);
1043         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1044         lenum = cpu_to_le64(owner);
1045         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1046         lenum = cpu_to_le64(offset);
1047         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1048
1049         return ((u64)high_crc << 31) ^ (u64)low_crc;
1050 }
1051
1052 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1053                                      struct btrfs_extent_data_ref *ref)
1054 {
1055         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1056                                     btrfs_extent_data_ref_objectid(leaf, ref),
1057                                     btrfs_extent_data_ref_offset(leaf, ref));
1058 }
1059
1060 static int match_extent_data_ref(struct extent_buffer *leaf,
1061                                  struct btrfs_extent_data_ref *ref,
1062                                  u64 root_objectid, u64 owner, u64 offset)
1063 {
1064         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1065             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1066             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1067                 return 0;
1068         return 1;
1069 }
1070
1071 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1072                                            struct btrfs_root *root,
1073                                            struct btrfs_path *path,
1074                                            u64 bytenr, u64 parent,
1075                                            u64 root_objectid,
1076                                            u64 owner, u64 offset)
1077 {
1078         struct btrfs_key key;
1079         struct btrfs_extent_data_ref *ref;
1080         struct extent_buffer *leaf;
1081         u32 nritems;
1082         int ret;
1083         int recow;
1084         int err = -ENOENT;
1085
1086         key.objectid = bytenr;
1087         if (parent) {
1088                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1089                 key.offset = parent;
1090         } else {
1091                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1092                 key.offset = hash_extent_data_ref(root_objectid,
1093                                                   owner, offset);
1094         }
1095 again:
1096         recow = 0;
1097         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1098         if (ret < 0) {
1099                 err = ret;
1100                 goto fail;
1101         }
1102
1103         if (parent) {
1104                 if (!ret)
1105                         return 0;
1106 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1107                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1108                 btrfs_release_path(path);
1109                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1110                 if (ret < 0) {
1111                         err = ret;
1112                         goto fail;
1113                 }
1114                 if (!ret)
1115                         return 0;
1116 #endif
1117                 goto fail;
1118         }
1119
1120         leaf = path->nodes[0];
1121         nritems = btrfs_header_nritems(leaf);
1122         while (1) {
1123                 if (path->slots[0] >= nritems) {
1124                         ret = btrfs_next_leaf(root, path);
1125                         if (ret < 0)
1126                                 err = ret;
1127                         if (ret)
1128                                 goto fail;
1129
1130                         leaf = path->nodes[0];
1131                         nritems = btrfs_header_nritems(leaf);
1132                         recow = 1;
1133                 }
1134
1135                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1136                 if (key.objectid != bytenr ||
1137                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1138                         goto fail;
1139
1140                 ref = btrfs_item_ptr(leaf, path->slots[0],
1141                                      struct btrfs_extent_data_ref);
1142
1143                 if (match_extent_data_ref(leaf, ref, root_objectid,
1144                                           owner, offset)) {
1145                         if (recow) {
1146                                 btrfs_release_path(path);
1147                                 goto again;
1148                         }
1149                         err = 0;
1150                         break;
1151                 }
1152                 path->slots[0]++;
1153         }
1154 fail:
1155         return err;
1156 }
1157
1158 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1159                                            struct btrfs_root *root,
1160                                            struct btrfs_path *path,
1161                                            u64 bytenr, u64 parent,
1162                                            u64 root_objectid, u64 owner,
1163                                            u64 offset, int refs_to_add)
1164 {
1165         struct btrfs_key key;
1166         struct extent_buffer *leaf;
1167         u32 size;
1168         u32 num_refs;
1169         int ret;
1170
1171         key.objectid = bytenr;
1172         if (parent) {
1173                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1174                 key.offset = parent;
1175                 size = sizeof(struct btrfs_shared_data_ref);
1176         } else {
1177                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1178                 key.offset = hash_extent_data_ref(root_objectid,
1179                                                   owner, offset);
1180                 size = sizeof(struct btrfs_extent_data_ref);
1181         }
1182
1183         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1184         if (ret && ret != -EEXIST)
1185                 goto fail;
1186
1187         leaf = path->nodes[0];
1188         if (parent) {
1189                 struct btrfs_shared_data_ref *ref;
1190                 ref = btrfs_item_ptr(leaf, path->slots[0],
1191                                      struct btrfs_shared_data_ref);
1192                 if (ret == 0) {
1193                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1194                 } else {
1195                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1196                         num_refs += refs_to_add;
1197                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1198                 }
1199         } else {
1200                 struct btrfs_extent_data_ref *ref;
1201                 while (ret == -EEXIST) {
1202                         ref = btrfs_item_ptr(leaf, path->slots[0],
1203                                              struct btrfs_extent_data_ref);
1204                         if (match_extent_data_ref(leaf, ref, root_objectid,
1205                                                   owner, offset))
1206                                 break;
1207                         btrfs_release_path(path);
1208                         key.offset++;
1209                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1210                                                       size);
1211                         if (ret && ret != -EEXIST)
1212                                 goto fail;
1213
1214                         leaf = path->nodes[0];
1215                 }
1216                 ref = btrfs_item_ptr(leaf, path->slots[0],
1217                                      struct btrfs_extent_data_ref);
1218                 if (ret == 0) {
1219                         btrfs_set_extent_data_ref_root(leaf, ref,
1220                                                        root_objectid);
1221                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1222                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1223                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1224                 } else {
1225                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1226                         num_refs += refs_to_add;
1227                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1228                 }
1229         }
1230         btrfs_mark_buffer_dirty(leaf);
1231         ret = 0;
1232 fail:
1233         btrfs_release_path(path);
1234         return ret;
1235 }
1236
1237 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1238                                            struct btrfs_root *root,
1239                                            struct btrfs_path *path,
1240                                            int refs_to_drop)
1241 {
1242         struct btrfs_key key;
1243         struct btrfs_extent_data_ref *ref1 = NULL;
1244         struct btrfs_shared_data_ref *ref2 = NULL;
1245         struct extent_buffer *leaf;
1246         u32 num_refs = 0;
1247         int ret = 0;
1248
1249         leaf = path->nodes[0];
1250         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1251
1252         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1253                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1254                                       struct btrfs_extent_data_ref);
1255                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1256         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1257                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1258                                       struct btrfs_shared_data_ref);
1259                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1260 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1261         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1262                 struct btrfs_extent_ref_v0 *ref0;
1263                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1264                                       struct btrfs_extent_ref_v0);
1265                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1266 #endif
1267         } else {
1268                 BUG();
1269         }
1270
1271         BUG_ON(num_refs < refs_to_drop);
1272         num_refs -= refs_to_drop;
1273
1274         if (num_refs == 0) {
1275                 ret = btrfs_del_item(trans, root, path);
1276         } else {
1277                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1278                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1279                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1280                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1281 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1282                 else {
1283                         struct btrfs_extent_ref_v0 *ref0;
1284                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1285                                         struct btrfs_extent_ref_v0);
1286                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1287                 }
1288 #endif
1289                 btrfs_mark_buffer_dirty(leaf);
1290         }
1291         return ret;
1292 }
1293
1294 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1295                                           struct btrfs_path *path,
1296                                           struct btrfs_extent_inline_ref *iref)
1297 {
1298         struct btrfs_key key;
1299         struct extent_buffer *leaf;
1300         struct btrfs_extent_data_ref *ref1;
1301         struct btrfs_shared_data_ref *ref2;
1302         u32 num_refs = 0;
1303
1304         leaf = path->nodes[0];
1305         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1306         if (iref) {
1307                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1308                     BTRFS_EXTENT_DATA_REF_KEY) {
1309                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1310                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1311                 } else {
1312                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1313                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1314                 }
1315         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1316                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1317                                       struct btrfs_extent_data_ref);
1318                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1319         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1320                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1321                                       struct btrfs_shared_data_ref);
1322                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1323 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1324         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1325                 struct btrfs_extent_ref_v0 *ref0;
1326                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1327                                       struct btrfs_extent_ref_v0);
1328                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1329 #endif
1330         } else {
1331                 WARN_ON(1);
1332         }
1333         return num_refs;
1334 }
1335
1336 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1337                                           struct btrfs_root *root,
1338                                           struct btrfs_path *path,
1339                                           u64 bytenr, u64 parent,
1340                                           u64 root_objectid)
1341 {
1342         struct btrfs_key key;
1343         int ret;
1344
1345         key.objectid = bytenr;
1346         if (parent) {
1347                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1348                 key.offset = parent;
1349         } else {
1350                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1351                 key.offset = root_objectid;
1352         }
1353
1354         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1355         if (ret > 0)
1356                 ret = -ENOENT;
1357 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1358         if (ret == -ENOENT && parent) {
1359                 btrfs_release_path(path);
1360                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1361                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1362                 if (ret > 0)
1363                         ret = -ENOENT;
1364         }
1365 #endif
1366         return ret;
1367 }
1368
1369 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1370                                           struct btrfs_root *root,
1371                                           struct btrfs_path *path,
1372                                           u64 bytenr, u64 parent,
1373                                           u64 root_objectid)
1374 {
1375         struct btrfs_key key;
1376         int ret;
1377
1378         key.objectid = bytenr;
1379         if (parent) {
1380                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1381                 key.offset = parent;
1382         } else {
1383                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1384                 key.offset = root_objectid;
1385         }
1386
1387         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1388         btrfs_release_path(path);
1389         return ret;
1390 }
1391
1392 static inline int extent_ref_type(u64 parent, u64 owner)
1393 {
1394         int type;
1395         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1396                 if (parent > 0)
1397                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1398                 else
1399                         type = BTRFS_TREE_BLOCK_REF_KEY;
1400         } else {
1401                 if (parent > 0)
1402                         type = BTRFS_SHARED_DATA_REF_KEY;
1403                 else
1404                         type = BTRFS_EXTENT_DATA_REF_KEY;
1405         }
1406         return type;
1407 }
1408
1409 static int find_next_key(struct btrfs_path *path, int level,
1410                          struct btrfs_key *key)
1411
1412 {
1413         for (; level < BTRFS_MAX_LEVEL; level++) {
1414                 if (!path->nodes[level])
1415                         break;
1416                 if (path->slots[level] + 1 >=
1417                     btrfs_header_nritems(path->nodes[level]))
1418                         continue;
1419                 if (level == 0)
1420                         btrfs_item_key_to_cpu(path->nodes[level], key,
1421                                               path->slots[level] + 1);
1422                 else
1423                         btrfs_node_key_to_cpu(path->nodes[level], key,
1424                                               path->slots[level] + 1);
1425                 return 0;
1426         }
1427         return 1;
1428 }
1429
1430 /*
1431  * look for inline back ref. if back ref is found, *ref_ret is set
1432  * to the address of inline back ref, and 0 is returned.
1433  *
1434  * if back ref isn't found, *ref_ret is set to the address where it
1435  * should be inserted, and -ENOENT is returned.
1436  *
1437  * if insert is true and there are too many inline back refs, the path
1438  * points to the extent item, and -EAGAIN is returned.
1439  *
1440  * NOTE: inline back refs are ordered in the same way that back ref
1441  *       items in the tree are ordered.
1442  */
1443 static noinline_for_stack
1444 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1445                                  struct btrfs_root *root,
1446                                  struct btrfs_path *path,
1447                                  struct btrfs_extent_inline_ref **ref_ret,
1448                                  u64 bytenr, u64 num_bytes,
1449                                  u64 parent, u64 root_objectid,
1450                                  u64 owner, u64 offset, int insert)
1451 {
1452         struct btrfs_key key;
1453         struct extent_buffer *leaf;
1454         struct btrfs_extent_item *ei;
1455         struct btrfs_extent_inline_ref *iref;
1456         u64 flags;
1457         u64 item_size;
1458         unsigned long ptr;
1459         unsigned long end;
1460         int extra_size;
1461         int type;
1462         int want;
1463         int ret;
1464         int err = 0;
1465
1466         key.objectid = bytenr;
1467         key.type = BTRFS_EXTENT_ITEM_KEY;
1468         key.offset = num_bytes;
1469
1470         want = extent_ref_type(parent, owner);
1471         if (insert) {
1472                 extra_size = btrfs_extent_inline_ref_size(want);
1473                 path->keep_locks = 1;
1474         } else
1475                 extra_size = -1;
1476         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1477         if (ret < 0) {
1478                 err = ret;
1479                 goto out;
1480         }
1481         BUG_ON(ret);
1482
1483         leaf = path->nodes[0];
1484         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1485 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1486         if (item_size < sizeof(*ei)) {
1487                 if (!insert) {
1488                         err = -ENOENT;
1489                         goto out;
1490                 }
1491                 ret = convert_extent_item_v0(trans, root, path, owner,
1492                                              extra_size);
1493                 if (ret < 0) {
1494                         err = ret;
1495                         goto out;
1496                 }
1497                 leaf = path->nodes[0];
1498                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1499         }
1500 #endif
1501         BUG_ON(item_size < sizeof(*ei));
1502
1503         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1504         flags = btrfs_extent_flags(leaf, ei);
1505
1506         ptr = (unsigned long)(ei + 1);
1507         end = (unsigned long)ei + item_size;
1508
1509         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1510                 ptr += sizeof(struct btrfs_tree_block_info);
1511                 BUG_ON(ptr > end);
1512         } else {
1513                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1514         }
1515
1516         err = -ENOENT;
1517         while (1) {
1518                 if (ptr >= end) {
1519                         WARN_ON(ptr > end);
1520                         break;
1521                 }
1522                 iref = (struct btrfs_extent_inline_ref *)ptr;
1523                 type = btrfs_extent_inline_ref_type(leaf, iref);
1524                 if (want < type)
1525                         break;
1526                 if (want > type) {
1527                         ptr += btrfs_extent_inline_ref_size(type);
1528                         continue;
1529                 }
1530
1531                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1532                         struct btrfs_extent_data_ref *dref;
1533                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1534                         if (match_extent_data_ref(leaf, dref, root_objectid,
1535                                                   owner, offset)) {
1536                                 err = 0;
1537                                 break;
1538                         }
1539                         if (hash_extent_data_ref_item(leaf, dref) <
1540                             hash_extent_data_ref(root_objectid, owner, offset))
1541                                 break;
1542                 } else {
1543                         u64 ref_offset;
1544                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1545                         if (parent > 0) {
1546                                 if (parent == ref_offset) {
1547                                         err = 0;
1548                                         break;
1549                                 }
1550                                 if (ref_offset < parent)
1551                                         break;
1552                         } else {
1553                                 if (root_objectid == ref_offset) {
1554                                         err = 0;
1555                                         break;
1556                                 }
1557                                 if (ref_offset < root_objectid)
1558                                         break;
1559                         }
1560                 }
1561                 ptr += btrfs_extent_inline_ref_size(type);
1562         }
1563         if (err == -ENOENT && insert) {
1564                 if (item_size + extra_size >=
1565                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1566                         err = -EAGAIN;
1567                         goto out;
1568                 }
1569                 /*
1570                  * To add new inline back ref, we have to make sure
1571                  * there is no corresponding back ref item.
1572                  * For simplicity, we just do not add new inline back
1573                  * ref if there is any kind of item for this block
1574                  */
1575                 if (find_next_key(path, 0, &key) == 0 &&
1576                     key.objectid == bytenr &&
1577                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1578                         err = -EAGAIN;
1579                         goto out;
1580                 }
1581         }
1582         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1583 out:
1584         if (insert) {
1585                 path->keep_locks = 0;
1586                 btrfs_unlock_up_safe(path, 1);
1587         }
1588         return err;
1589 }
1590
1591 /*
1592  * helper to add new inline back ref
1593  */
1594 static noinline_for_stack
1595 int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1596                                 struct btrfs_root *root,
1597                                 struct btrfs_path *path,
1598                                 struct btrfs_extent_inline_ref *iref,
1599                                 u64 parent, u64 root_objectid,
1600                                 u64 owner, u64 offset, int refs_to_add,
1601                                 struct btrfs_delayed_extent_op *extent_op)
1602 {
1603         struct extent_buffer *leaf;
1604         struct btrfs_extent_item *ei;
1605         unsigned long ptr;
1606         unsigned long end;
1607         unsigned long item_offset;
1608         u64 refs;
1609         int size;
1610         int type;
1611         int ret;
1612
1613         leaf = path->nodes[0];
1614         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1615         item_offset = (unsigned long)iref - (unsigned long)ei;
1616
1617         type = extent_ref_type(parent, owner);
1618         size = btrfs_extent_inline_ref_size(type);
1619
1620         ret = btrfs_extend_item(trans, root, path, size);
1621
1622         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1623         refs = btrfs_extent_refs(leaf, ei);
1624         refs += refs_to_add;
1625         btrfs_set_extent_refs(leaf, ei, refs);
1626         if (extent_op)
1627                 __run_delayed_extent_op(extent_op, leaf, ei);
1628
1629         ptr = (unsigned long)ei + item_offset;
1630         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1631         if (ptr < end - size)
1632                 memmove_extent_buffer(leaf, ptr + size, ptr,
1633                                       end - size - ptr);
1634
1635         iref = (struct btrfs_extent_inline_ref *)ptr;
1636         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1637         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1638                 struct btrfs_extent_data_ref *dref;
1639                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1640                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1641                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1642                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1643                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1644         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1645                 struct btrfs_shared_data_ref *sref;
1646                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1647                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1648                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1649         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1650                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1651         } else {
1652                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1653         }
1654         btrfs_mark_buffer_dirty(leaf);
1655         return 0;
1656 }
1657
1658 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1659                                  struct btrfs_root *root,
1660                                  struct btrfs_path *path,
1661                                  struct btrfs_extent_inline_ref **ref_ret,
1662                                  u64 bytenr, u64 num_bytes, u64 parent,
1663                                  u64 root_objectid, u64 owner, u64 offset)
1664 {
1665         int ret;
1666
1667         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1668                                            bytenr, num_bytes, parent,
1669                                            root_objectid, owner, offset, 0);
1670         if (ret != -ENOENT)
1671                 return ret;
1672
1673         btrfs_release_path(path);
1674         *ref_ret = NULL;
1675
1676         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1677                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1678                                             root_objectid);
1679         } else {
1680                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1681                                              root_objectid, owner, offset);
1682         }
1683         return ret;
1684 }
1685
1686 /*
1687  * helper to update/remove inline back ref
1688  */
1689 static noinline_for_stack
1690 int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1691                                  struct btrfs_root *root,
1692                                  struct btrfs_path *path,
1693                                  struct btrfs_extent_inline_ref *iref,
1694                                  int refs_to_mod,
1695                                  struct btrfs_delayed_extent_op *extent_op)
1696 {
1697         struct extent_buffer *leaf;
1698         struct btrfs_extent_item *ei;
1699         struct btrfs_extent_data_ref *dref = NULL;
1700         struct btrfs_shared_data_ref *sref = NULL;
1701         unsigned long ptr;
1702         unsigned long end;
1703         u32 item_size;
1704         int size;
1705         int type;
1706         int ret;
1707         u64 refs;
1708
1709         leaf = path->nodes[0];
1710         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1711         refs = btrfs_extent_refs(leaf, ei);
1712         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1713         refs += refs_to_mod;
1714         btrfs_set_extent_refs(leaf, ei, refs);
1715         if (extent_op)
1716                 __run_delayed_extent_op(extent_op, leaf, ei);
1717
1718         type = btrfs_extent_inline_ref_type(leaf, iref);
1719
1720         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1721                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1722                 refs = btrfs_extent_data_ref_count(leaf, dref);
1723         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1724                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1725                 refs = btrfs_shared_data_ref_count(leaf, sref);
1726         } else {
1727                 refs = 1;
1728                 BUG_ON(refs_to_mod != -1);
1729         }
1730
1731         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1732         refs += refs_to_mod;
1733
1734         if (refs > 0) {
1735                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1736                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1737                 else
1738                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1739         } else {
1740                 size =  btrfs_extent_inline_ref_size(type);
1741                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1742                 ptr = (unsigned long)iref;
1743                 end = (unsigned long)ei + item_size;
1744                 if (ptr + size < end)
1745                         memmove_extent_buffer(leaf, ptr, ptr + size,
1746                                               end - ptr - size);
1747                 item_size -= size;
1748                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1749         }
1750         btrfs_mark_buffer_dirty(leaf);
1751         return 0;
1752 }
1753
1754 static noinline_for_stack
1755 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1756                                  struct btrfs_root *root,
1757                                  struct btrfs_path *path,
1758                                  u64 bytenr, u64 num_bytes, u64 parent,
1759                                  u64 root_objectid, u64 owner,
1760                                  u64 offset, int refs_to_add,
1761                                  struct btrfs_delayed_extent_op *extent_op)
1762 {
1763         struct btrfs_extent_inline_ref *iref;
1764         int ret;
1765
1766         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1767                                            bytenr, num_bytes, parent,
1768                                            root_objectid, owner, offset, 1);
1769         if (ret == 0) {
1770                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1771                 ret = update_inline_extent_backref(trans, root, path, iref,
1772                                                    refs_to_add, extent_op);
1773         } else if (ret == -ENOENT) {
1774                 ret = setup_inline_extent_backref(trans, root, path, iref,
1775                                                   parent, root_objectid,
1776                                                   owner, offset, refs_to_add,
1777                                                   extent_op);
1778         }
1779         return ret;
1780 }
1781
1782 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1783                                  struct btrfs_root *root,
1784                                  struct btrfs_path *path,
1785                                  u64 bytenr, u64 parent, u64 root_objectid,
1786                                  u64 owner, u64 offset, int refs_to_add)
1787 {
1788         int ret;
1789         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1790                 BUG_ON(refs_to_add != 1);
1791                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1792                                             parent, root_objectid);
1793         } else {
1794                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1795                                              parent, root_objectid,
1796                                              owner, offset, refs_to_add);
1797         }
1798         return ret;
1799 }
1800
1801 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1802                                  struct btrfs_root *root,
1803                                  struct btrfs_path *path,
1804                                  struct btrfs_extent_inline_ref *iref,
1805                                  int refs_to_drop, int is_data)
1806 {
1807         int ret;
1808
1809         BUG_ON(!is_data && refs_to_drop != 1);
1810         if (iref) {
1811                 ret = update_inline_extent_backref(trans, root, path, iref,
1812                                                    -refs_to_drop, NULL);
1813         } else if (is_data) {
1814                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1815         } else {
1816                 ret = btrfs_del_item(trans, root, path);
1817         }
1818         return ret;
1819 }
1820
1821 static int btrfs_issue_discard(struct block_device *bdev,
1822                                 u64 start, u64 len)
1823 {
1824         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1825 }
1826
1827 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1828                                 u64 num_bytes, u64 *actual_bytes)
1829 {
1830         int ret;
1831         u64 discarded_bytes = 0;
1832         struct btrfs_bio *bbio = NULL;
1833
1834
1835         /* Tell the block device(s) that the sectors can be discarded */
1836         ret = btrfs_map_block(&root->fs_info->mapping_tree, REQ_DISCARD,
1837                               bytenr, &num_bytes, &bbio, 0);
1838         if (!ret) {
1839                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1840                 int i;
1841
1842
1843                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1844                         if (!stripe->dev->can_discard)
1845                                 continue;
1846
1847                         ret = btrfs_issue_discard(stripe->dev->bdev,
1848                                                   stripe->physical,
1849                                                   stripe->length);
1850                         if (!ret)
1851                                 discarded_bytes += stripe->length;
1852                         else if (ret != -EOPNOTSUPP)
1853                                 break;
1854
1855                         /*
1856                          * Just in case we get back EOPNOTSUPP for some reason,
1857                          * just ignore the return value so we don't screw up
1858                          * people calling discard_extent.
1859                          */
1860                         ret = 0;
1861                 }
1862                 kfree(bbio);
1863         }
1864
1865         if (actual_bytes)
1866                 *actual_bytes = discarded_bytes;
1867
1868
1869         return ret;
1870 }
1871
1872 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1873                          struct btrfs_root *root,
1874                          u64 bytenr, u64 num_bytes, u64 parent,
1875                          u64 root_objectid, u64 owner, u64 offset)
1876 {
1877         int ret;
1878         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1879                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1880
1881         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1882                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
1883                                         parent, root_objectid, (int)owner,
1884                                         BTRFS_ADD_DELAYED_REF, NULL);
1885         } else {
1886                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
1887                                         parent, root_objectid, owner, offset,
1888                                         BTRFS_ADD_DELAYED_REF, NULL);
1889         }
1890         return ret;
1891 }
1892
1893 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1894                                   struct btrfs_root *root,
1895                                   u64 bytenr, u64 num_bytes,
1896                                   u64 parent, u64 root_objectid,
1897                                   u64 owner, u64 offset, int refs_to_add,
1898                                   struct btrfs_delayed_extent_op *extent_op)
1899 {
1900         struct btrfs_path *path;
1901         struct extent_buffer *leaf;
1902         struct btrfs_extent_item *item;
1903         u64 refs;
1904         int ret;
1905         int err = 0;
1906
1907         path = btrfs_alloc_path();
1908         if (!path)
1909                 return -ENOMEM;
1910
1911         path->reada = 1;
1912         path->leave_spinning = 1;
1913         /* this will setup the path even if it fails to insert the back ref */
1914         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1915                                            path, bytenr, num_bytes, parent,
1916                                            root_objectid, owner, offset,
1917                                            refs_to_add, extent_op);
1918         if (ret == 0)
1919                 goto out;
1920
1921         if (ret != -EAGAIN) {
1922                 err = ret;
1923                 goto out;
1924         }
1925
1926         leaf = path->nodes[0];
1927         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1928         refs = btrfs_extent_refs(leaf, item);
1929         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1930         if (extent_op)
1931                 __run_delayed_extent_op(extent_op, leaf, item);
1932
1933         btrfs_mark_buffer_dirty(leaf);
1934         btrfs_release_path(path);
1935
1936         path->reada = 1;
1937         path->leave_spinning = 1;
1938
1939         /* now insert the actual backref */
1940         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1941                                     path, bytenr, parent, root_objectid,
1942                                     owner, offset, refs_to_add);
1943         BUG_ON(ret);
1944 out:
1945         btrfs_free_path(path);
1946         return err;
1947 }
1948
1949 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1950                                 struct btrfs_root *root,
1951                                 struct btrfs_delayed_ref_node *node,
1952                                 struct btrfs_delayed_extent_op *extent_op,
1953                                 int insert_reserved)
1954 {
1955         int ret = 0;
1956         struct btrfs_delayed_data_ref *ref;
1957         struct btrfs_key ins;
1958         u64 parent = 0;
1959         u64 ref_root = 0;
1960         u64 flags = 0;
1961
1962         ins.objectid = node->bytenr;
1963         ins.offset = node->num_bytes;
1964         ins.type = BTRFS_EXTENT_ITEM_KEY;
1965
1966         ref = btrfs_delayed_node_to_data_ref(node);
1967         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1968                 parent = ref->parent;
1969         else
1970                 ref_root = ref->root;
1971
1972         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1973                 if (extent_op) {
1974                         BUG_ON(extent_op->update_key);
1975                         flags |= extent_op->flags_to_set;
1976                 }
1977                 ret = alloc_reserved_file_extent(trans, root,
1978                                                  parent, ref_root, flags,
1979                                                  ref->objectid, ref->offset,
1980                                                  &ins, node->ref_mod);
1981         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1982                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1983                                              node->num_bytes, parent,
1984                                              ref_root, ref->objectid,
1985                                              ref->offset, node->ref_mod,
1986                                              extent_op);
1987         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1988                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1989                                           node->num_bytes, parent,
1990                                           ref_root, ref->objectid,
1991                                           ref->offset, node->ref_mod,
1992                                           extent_op);
1993         } else {
1994                 BUG();
1995         }
1996         return ret;
1997 }
1998
1999 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2000                                     struct extent_buffer *leaf,
2001                                     struct btrfs_extent_item *ei)
2002 {
2003         u64 flags = btrfs_extent_flags(leaf, ei);
2004         if (extent_op->update_flags) {
2005                 flags |= extent_op->flags_to_set;
2006                 btrfs_set_extent_flags(leaf, ei, flags);
2007         }
2008
2009         if (extent_op->update_key) {
2010                 struct btrfs_tree_block_info *bi;
2011                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2012                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2013                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2014         }
2015 }
2016
2017 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2018                                  struct btrfs_root *root,
2019                                  struct btrfs_delayed_ref_node *node,
2020                                  struct btrfs_delayed_extent_op *extent_op)
2021 {
2022         struct btrfs_key key;
2023         struct btrfs_path *path;
2024         struct btrfs_extent_item *ei;
2025         struct extent_buffer *leaf;
2026         u32 item_size;
2027         int ret;
2028         int err = 0;
2029
2030         path = btrfs_alloc_path();
2031         if (!path)
2032                 return -ENOMEM;
2033
2034         key.objectid = node->bytenr;
2035         key.type = BTRFS_EXTENT_ITEM_KEY;
2036         key.offset = node->num_bytes;
2037
2038         path->reada = 1;
2039         path->leave_spinning = 1;
2040         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2041                                 path, 0, 1);
2042         if (ret < 0) {
2043                 err = ret;
2044                 goto out;
2045         }
2046         if (ret > 0) {
2047                 err = -EIO;
2048                 goto out;
2049         }
2050
2051         leaf = path->nodes[0];
2052         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2053 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2054         if (item_size < sizeof(*ei)) {
2055                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2056                                              path, (u64)-1, 0);
2057                 if (ret < 0) {
2058                         err = ret;
2059                         goto out;
2060                 }
2061                 leaf = path->nodes[0];
2062                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2063         }
2064 #endif
2065         BUG_ON(item_size < sizeof(*ei));
2066         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2067         __run_delayed_extent_op(extent_op, leaf, ei);
2068
2069         btrfs_mark_buffer_dirty(leaf);
2070 out:
2071         btrfs_free_path(path);
2072         return err;
2073 }
2074
2075 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2076                                 struct btrfs_root *root,
2077                                 struct btrfs_delayed_ref_node *node,
2078                                 struct btrfs_delayed_extent_op *extent_op,
2079                                 int insert_reserved)
2080 {
2081         int ret = 0;
2082         struct btrfs_delayed_tree_ref *ref;
2083         struct btrfs_key ins;
2084         u64 parent = 0;
2085         u64 ref_root = 0;
2086
2087         ins.objectid = node->bytenr;
2088         ins.offset = node->num_bytes;
2089         ins.type = BTRFS_EXTENT_ITEM_KEY;
2090
2091         ref = btrfs_delayed_node_to_tree_ref(node);
2092         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2093                 parent = ref->parent;
2094         else
2095                 ref_root = ref->root;
2096
2097         BUG_ON(node->ref_mod != 1);
2098         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2099                 BUG_ON(!extent_op || !extent_op->update_flags ||
2100                        !extent_op->update_key);
2101                 ret = alloc_reserved_tree_block(trans, root,
2102                                                 parent, ref_root,
2103                                                 extent_op->flags_to_set,
2104                                                 &extent_op->key,
2105                                                 ref->level, &ins);
2106         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2107                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2108                                              node->num_bytes, parent, ref_root,
2109                                              ref->level, 0, 1, extent_op);
2110         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2111                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2112                                           node->num_bytes, parent, ref_root,
2113                                           ref->level, 0, 1, extent_op);
2114         } else {
2115                 BUG();
2116         }
2117         return ret;
2118 }
2119
2120 /* helper function to actually process a single delayed ref entry */
2121 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2122                                struct btrfs_root *root,
2123                                struct btrfs_delayed_ref_node *node,
2124                                struct btrfs_delayed_extent_op *extent_op,
2125                                int insert_reserved)
2126 {
2127         int ret;
2128         if (btrfs_delayed_ref_is_head(node)) {
2129                 struct btrfs_delayed_ref_head *head;
2130                 /*
2131                  * we've hit the end of the chain and we were supposed
2132                  * to insert this extent into the tree.  But, it got
2133                  * deleted before we ever needed to insert it, so all
2134                  * we have to do is clean up the accounting
2135                  */
2136                 BUG_ON(extent_op);
2137                 head = btrfs_delayed_node_to_head(node);
2138                 if (insert_reserved) {
2139                         btrfs_pin_extent(root, node->bytenr,
2140                                          node->num_bytes, 1);
2141                         if (head->is_data) {
2142                                 ret = btrfs_del_csums(trans, root,
2143                                                       node->bytenr,
2144                                                       node->num_bytes);
2145                                 BUG_ON(ret);
2146                         }
2147                 }
2148                 mutex_unlock(&head->mutex);
2149                 return 0;
2150         }
2151
2152         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2153             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2154                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2155                                            insert_reserved);
2156         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2157                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2158                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2159                                            insert_reserved);
2160         else
2161                 BUG();
2162         return ret;
2163 }
2164
2165 static noinline struct btrfs_delayed_ref_node *
2166 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2167 {
2168         struct rb_node *node;
2169         struct btrfs_delayed_ref_node *ref;
2170         int action = BTRFS_ADD_DELAYED_REF;
2171 again:
2172         /*
2173          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2174          * this prevents ref count from going down to zero when
2175          * there still are pending delayed ref.
2176          */
2177         node = rb_prev(&head->node.rb_node);
2178         while (1) {
2179                 if (!node)
2180                         break;
2181                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2182                                 rb_node);
2183                 if (ref->bytenr != head->node.bytenr)
2184                         break;
2185                 if (ref->action == action)
2186                         return ref;
2187                 node = rb_prev(node);
2188         }
2189         if (action == BTRFS_ADD_DELAYED_REF) {
2190                 action = BTRFS_DROP_DELAYED_REF;
2191                 goto again;
2192         }
2193         return NULL;
2194 }
2195
2196 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2197                                        struct btrfs_root *root,
2198                                        struct list_head *cluster)
2199 {
2200         struct btrfs_delayed_ref_root *delayed_refs;
2201         struct btrfs_delayed_ref_node *ref;
2202         struct btrfs_delayed_ref_head *locked_ref = NULL;
2203         struct btrfs_delayed_extent_op *extent_op;
2204         int ret;
2205         int count = 0;
2206         int must_insert_reserved = 0;
2207
2208         delayed_refs = &trans->transaction->delayed_refs;
2209         while (1) {
2210                 if (!locked_ref) {
2211                         /* pick a new head ref from the cluster list */
2212                         if (list_empty(cluster))
2213                                 break;
2214
2215                         locked_ref = list_entry(cluster->next,
2216                                      struct btrfs_delayed_ref_head, cluster);
2217
2218                         /* grab the lock that says we are going to process
2219                          * all the refs for this head */
2220                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2221
2222                         /*
2223                          * we may have dropped the spin lock to get the head
2224                          * mutex lock, and that might have given someone else
2225                          * time to free the head.  If that's true, it has been
2226                          * removed from our list and we can move on.
2227                          */
2228                         if (ret == -EAGAIN) {
2229                                 locked_ref = NULL;
2230                                 count++;
2231                                 continue;
2232                         }
2233                 }
2234
2235                 /*
2236                  * record the must insert reserved flag before we
2237                  * drop the spin lock.
2238                  */
2239                 must_insert_reserved = locked_ref->must_insert_reserved;
2240                 locked_ref->must_insert_reserved = 0;
2241
2242                 extent_op = locked_ref->extent_op;
2243                 locked_ref->extent_op = NULL;
2244
2245                 /*
2246                  * locked_ref is the head node, so we have to go one
2247                  * node back for any delayed ref updates
2248                  */
2249                 ref = select_delayed_ref(locked_ref);
2250                 if (!ref) {
2251                         /* All delayed refs have been processed, Go ahead
2252                          * and send the head node to run_one_delayed_ref,
2253                          * so that any accounting fixes can happen
2254                          */
2255                         ref = &locked_ref->node;
2256
2257                         if (extent_op && must_insert_reserved) {
2258                                 kfree(extent_op);
2259                                 extent_op = NULL;
2260                         }
2261
2262                         if (extent_op) {
2263                                 spin_unlock(&delayed_refs->lock);
2264
2265                                 ret = run_delayed_extent_op(trans, root,
2266                                                             ref, extent_op);
2267                                 BUG_ON(ret);
2268                                 kfree(extent_op);
2269
2270                                 cond_resched();
2271                                 spin_lock(&delayed_refs->lock);
2272                                 continue;
2273                         }
2274
2275                         list_del_init(&locked_ref->cluster);
2276                         locked_ref = NULL;
2277                 }
2278
2279                 ref->in_tree = 0;
2280                 rb_erase(&ref->rb_node, &delayed_refs->root);
2281                 delayed_refs->num_entries--;
2282
2283                 spin_unlock(&delayed_refs->lock);
2284
2285                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2286                                           must_insert_reserved);
2287                 BUG_ON(ret);
2288
2289                 btrfs_put_delayed_ref(ref);
2290                 kfree(extent_op);
2291                 count++;
2292
2293                 cond_resched();
2294                 spin_lock(&delayed_refs->lock);
2295         }
2296         return count;
2297 }
2298
2299 /*
2300  * this starts processing the delayed reference count updates and
2301  * extent insertions we have queued up so far.  count can be
2302  * 0, which means to process everything in the tree at the start
2303  * of the run (but not newly added entries), or it can be some target
2304  * number you'd like to process.
2305  */
2306 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2307                            struct btrfs_root *root, unsigned long count)
2308 {
2309         struct rb_node *node;
2310         struct btrfs_delayed_ref_root *delayed_refs;
2311         struct btrfs_delayed_ref_node *ref;
2312         struct list_head cluster;
2313         int ret;
2314         int run_all = count == (unsigned long)-1;
2315         int run_most = 0;
2316
2317         if (root == root->fs_info->extent_root)
2318                 root = root->fs_info->tree_root;
2319
2320         delayed_refs = &trans->transaction->delayed_refs;
2321         INIT_LIST_HEAD(&cluster);
2322 again:
2323         spin_lock(&delayed_refs->lock);
2324         if (count == 0) {
2325                 count = delayed_refs->num_entries * 2;
2326                 run_most = 1;
2327         }
2328         while (1) {
2329                 if (!(run_all || run_most) &&
2330                     delayed_refs->num_heads_ready < 64)
2331                         break;
2332
2333                 /*
2334                  * go find something we can process in the rbtree.  We start at
2335                  * the beginning of the tree, and then build a cluster
2336                  * of refs to process starting at the first one we are able to
2337                  * lock
2338                  */
2339                 ret = btrfs_find_ref_cluster(trans, &cluster,
2340                                              delayed_refs->run_delayed_start);
2341                 if (ret)
2342                         break;
2343
2344                 ret = run_clustered_refs(trans, root, &cluster);
2345                 BUG_ON(ret < 0);
2346
2347                 count -= min_t(unsigned long, ret, count);
2348
2349                 if (count == 0)
2350                         break;
2351         }
2352
2353         if (run_all) {
2354                 node = rb_first(&delayed_refs->root);
2355                 if (!node)
2356                         goto out;
2357                 count = (unsigned long)-1;
2358
2359                 while (node) {
2360                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2361                                        rb_node);
2362                         if (btrfs_delayed_ref_is_head(ref)) {
2363                                 struct btrfs_delayed_ref_head *head;
2364
2365                                 head = btrfs_delayed_node_to_head(ref);
2366                                 atomic_inc(&ref->refs);
2367
2368                                 spin_unlock(&delayed_refs->lock);
2369                                 /*
2370                                  * Mutex was contended, block until it's
2371                                  * released and try again
2372                                  */
2373                                 mutex_lock(&head->mutex);
2374                                 mutex_unlock(&head->mutex);
2375
2376                                 btrfs_put_delayed_ref(ref);
2377                                 cond_resched();
2378                                 goto again;
2379                         }
2380                         node = rb_next(node);
2381                 }
2382                 spin_unlock(&delayed_refs->lock);
2383                 schedule_timeout(1);
2384                 goto again;
2385         }
2386 out:
2387         spin_unlock(&delayed_refs->lock);
2388         return 0;
2389 }
2390
2391 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2392                                 struct btrfs_root *root,
2393                                 u64 bytenr, u64 num_bytes, u64 flags,
2394                                 int is_data)
2395 {
2396         struct btrfs_delayed_extent_op *extent_op;
2397         int ret;
2398
2399         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2400         if (!extent_op)
2401                 return -ENOMEM;
2402
2403         extent_op->flags_to_set = flags;
2404         extent_op->update_flags = 1;
2405         extent_op->update_key = 0;
2406         extent_op->is_data = is_data ? 1 : 0;
2407
2408         ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
2409         if (ret)
2410                 kfree(extent_op);
2411         return ret;
2412 }
2413
2414 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2415                                       struct btrfs_root *root,
2416                                       struct btrfs_path *path,
2417                                       u64 objectid, u64 offset, u64 bytenr)
2418 {
2419         struct btrfs_delayed_ref_head *head;
2420         struct btrfs_delayed_ref_node *ref;
2421         struct btrfs_delayed_data_ref *data_ref;
2422         struct btrfs_delayed_ref_root *delayed_refs;
2423         struct rb_node *node;
2424         int ret = 0;
2425
2426         ret = -ENOENT;
2427         delayed_refs = &trans->transaction->delayed_refs;
2428         spin_lock(&delayed_refs->lock);
2429         head = btrfs_find_delayed_ref_head(trans, bytenr);
2430         if (!head)
2431                 goto out;
2432
2433         if (!mutex_trylock(&head->mutex)) {
2434                 atomic_inc(&head->node.refs);
2435                 spin_unlock(&delayed_refs->lock);
2436
2437                 btrfs_release_path(path);
2438
2439                 /*
2440                  * Mutex was contended, block until it's released and let
2441                  * caller try again
2442                  */
2443                 mutex_lock(&head->mutex);
2444                 mutex_unlock(&head->mutex);
2445                 btrfs_put_delayed_ref(&head->node);
2446                 return -EAGAIN;
2447         }
2448
2449         node = rb_prev(&head->node.rb_node);
2450         if (!node)
2451                 goto out_unlock;
2452
2453         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2454
2455         if (ref->bytenr != bytenr)
2456                 goto out_unlock;
2457
2458         ret = 1;
2459         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2460                 goto out_unlock;
2461
2462         data_ref = btrfs_delayed_node_to_data_ref(ref);
2463
2464         node = rb_prev(node);
2465         if (node) {
2466                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2467                 if (ref->bytenr == bytenr)
2468                         goto out_unlock;
2469         }
2470
2471         if (data_ref->root != root->root_key.objectid ||
2472             data_ref->objectid != objectid || data_ref->offset != offset)
2473                 goto out_unlock;
2474
2475         ret = 0;
2476 out_unlock:
2477         mutex_unlock(&head->mutex);
2478 out:
2479         spin_unlock(&delayed_refs->lock);
2480         return ret;
2481 }
2482
2483 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2484                                         struct btrfs_root *root,
2485                                         struct btrfs_path *path,
2486                                         u64 objectid, u64 offset, u64 bytenr)
2487 {
2488         struct btrfs_root *extent_root = root->fs_info->extent_root;
2489         struct extent_buffer *leaf;
2490         struct btrfs_extent_data_ref *ref;
2491         struct btrfs_extent_inline_ref *iref;
2492         struct btrfs_extent_item *ei;
2493         struct btrfs_key key;
2494         u32 item_size;
2495         int ret;
2496
2497         key.objectid = bytenr;
2498         key.offset = (u64)-1;
2499         key.type = BTRFS_EXTENT_ITEM_KEY;
2500
2501         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2502         if (ret < 0)
2503                 goto out;
2504         BUG_ON(ret == 0);
2505
2506         ret = -ENOENT;
2507         if (path->slots[0] == 0)
2508                 goto out;
2509
2510         path->slots[0]--;
2511         leaf = path->nodes[0];
2512         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2513
2514         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2515                 goto out;
2516
2517         ret = 1;
2518         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2519 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2520         if (item_size < sizeof(*ei)) {
2521                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2522                 goto out;
2523         }
2524 #endif
2525         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2526
2527         if (item_size != sizeof(*ei) +
2528             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2529                 goto out;
2530
2531         if (btrfs_extent_generation(leaf, ei) <=
2532             btrfs_root_last_snapshot(&root->root_item))
2533                 goto out;
2534
2535         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2536         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2537             BTRFS_EXTENT_DATA_REF_KEY)
2538                 goto out;
2539
2540         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2541         if (btrfs_extent_refs(leaf, ei) !=
2542             btrfs_extent_data_ref_count(leaf, ref) ||
2543             btrfs_extent_data_ref_root(leaf, ref) !=
2544             root->root_key.objectid ||
2545             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2546             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2547                 goto out;
2548
2549         ret = 0;
2550 out:
2551         return ret;
2552 }
2553
2554 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2555                           struct btrfs_root *root,
2556                           u64 objectid, u64 offset, u64 bytenr)
2557 {
2558         struct btrfs_path *path;
2559         int ret;
2560         int ret2;
2561
2562         path = btrfs_alloc_path();
2563         if (!path)
2564                 return -ENOENT;
2565
2566         do {
2567                 ret = check_committed_ref(trans, root, path, objectid,
2568                                           offset, bytenr);
2569                 if (ret && ret != -ENOENT)
2570                         goto out;
2571
2572                 ret2 = check_delayed_ref(trans, root, path, objectid,
2573                                          offset, bytenr);
2574         } while (ret2 == -EAGAIN);
2575
2576         if (ret2 && ret2 != -ENOENT) {
2577                 ret = ret2;
2578                 goto out;
2579         }
2580
2581         if (ret != -ENOENT || ret2 != -ENOENT)
2582                 ret = 0;
2583 out:
2584         btrfs_free_path(path);
2585         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2586                 WARN_ON(ret > 0);
2587         return ret;
2588 }
2589
2590 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2591                            struct btrfs_root *root,
2592                            struct extent_buffer *buf,
2593                            int full_backref, int inc)
2594 {
2595         u64 bytenr;
2596         u64 num_bytes;
2597         u64 parent;
2598         u64 ref_root;
2599         u32 nritems;
2600         struct btrfs_key key;
2601         struct btrfs_file_extent_item *fi;
2602         int i;
2603         int level;
2604         int ret = 0;
2605         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2606                             u64, u64, u64, u64, u64, u64);
2607
2608         ref_root = btrfs_header_owner(buf);
2609         nritems = btrfs_header_nritems(buf);
2610         level = btrfs_header_level(buf);
2611
2612         if (!root->ref_cows && level == 0)
2613                 return 0;
2614
2615         if (inc)
2616                 process_func = btrfs_inc_extent_ref;
2617         else
2618                 process_func = btrfs_free_extent;
2619
2620         if (full_backref)
2621                 parent = buf->start;
2622         else
2623                 parent = 0;
2624
2625         for (i = 0; i < nritems; i++) {
2626                 if (level == 0) {
2627                         btrfs_item_key_to_cpu(buf, &key, i);
2628                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2629                                 continue;
2630                         fi = btrfs_item_ptr(buf, i,
2631                                             struct btrfs_file_extent_item);
2632                         if (btrfs_file_extent_type(buf, fi) ==
2633                             BTRFS_FILE_EXTENT_INLINE)
2634                                 continue;
2635                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2636                         if (bytenr == 0)
2637                                 continue;
2638
2639                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2640                         key.offset -= btrfs_file_extent_offset(buf, fi);
2641                         ret = process_func(trans, root, bytenr, num_bytes,
2642                                            parent, ref_root, key.objectid,
2643                                            key.offset);
2644                         if (ret)
2645                                 goto fail;
2646                 } else {
2647                         bytenr = btrfs_node_blockptr(buf, i);
2648                         num_bytes = btrfs_level_size(root, level - 1);
2649                         ret = process_func(trans, root, bytenr, num_bytes,
2650                                            parent, ref_root, level - 1, 0);
2651                         if (ret)
2652                                 goto fail;
2653                 }
2654         }
2655         return 0;
2656 fail:
2657         BUG();
2658         return ret;
2659 }
2660
2661 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2662                   struct extent_buffer *buf, int full_backref)
2663 {
2664         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2665 }
2666
2667 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2668                   struct extent_buffer *buf, int full_backref)
2669 {
2670         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2671 }
2672
2673 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2674                                  struct btrfs_root *root,
2675                                  struct btrfs_path *path,
2676                                  struct btrfs_block_group_cache *cache)
2677 {
2678         int ret;
2679         struct btrfs_root *extent_root = root->fs_info->extent_root;
2680         unsigned long bi;
2681         struct extent_buffer *leaf;
2682
2683         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2684         if (ret < 0)
2685                 goto fail;
2686         BUG_ON(ret);
2687
2688         leaf = path->nodes[0];
2689         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2690         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2691         btrfs_mark_buffer_dirty(leaf);
2692         btrfs_release_path(path);
2693 fail:
2694         if (ret)
2695                 return ret;
2696         return 0;
2697
2698 }
2699
2700 static struct btrfs_block_group_cache *
2701 next_block_group(struct btrfs_root *root,
2702                  struct btrfs_block_group_cache *cache)
2703 {
2704         struct rb_node *node;
2705         spin_lock(&root->fs_info->block_group_cache_lock);
2706         node = rb_next(&cache->cache_node);
2707         btrfs_put_block_group(cache);
2708         if (node) {
2709                 cache = rb_entry(node, struct btrfs_block_group_cache,
2710                                  cache_node);
2711                 btrfs_get_block_group(cache);
2712         } else
2713                 cache = NULL;
2714         spin_unlock(&root->fs_info->block_group_cache_lock);
2715         return cache;
2716 }
2717
2718 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2719                             struct btrfs_trans_handle *trans,
2720                             struct btrfs_path *path)
2721 {
2722         struct btrfs_root *root = block_group->fs_info->tree_root;
2723         struct inode *inode = NULL;
2724         u64 alloc_hint = 0;
2725         int dcs = BTRFS_DC_ERROR;
2726         int num_pages = 0;
2727         int retries = 0;
2728         int ret = 0;
2729
2730         /*
2731          * If this block group is smaller than 100 megs don't bother caching the
2732          * block group.
2733          */
2734         if (block_group->key.offset < (100 * 1024 * 1024)) {
2735                 spin_lock(&block_group->lock);
2736                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2737                 spin_unlock(&block_group->lock);
2738                 return 0;
2739         }
2740
2741 again:
2742         inode = lookup_free_space_inode(root, block_group, path);
2743         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2744                 ret = PTR_ERR(inode);
2745                 btrfs_release_path(path);
2746                 goto out;
2747         }
2748
2749         if (IS_ERR(inode)) {
2750                 BUG_ON(retries);
2751                 retries++;
2752
2753                 if (block_group->ro)
2754                         goto out_free;
2755
2756                 ret = create_free_space_inode(root, trans, block_group, path);
2757                 if (ret)
2758                         goto out_free;
2759                 goto again;
2760         }
2761
2762         /* We've already setup this transaction, go ahead and exit */
2763         if (block_group->cache_generation == trans->transid &&
2764             i_size_read(inode)) {
2765                 dcs = BTRFS_DC_SETUP;
2766                 goto out_put;
2767         }
2768
2769         /*
2770          * We want to set the generation to 0, that way if anything goes wrong
2771          * from here on out we know not to trust this cache when we load up next
2772          * time.
2773          */
2774         BTRFS_I(inode)->generation = 0;
2775         ret = btrfs_update_inode(trans, root, inode);
2776         WARN_ON(ret);
2777
2778         if (i_size_read(inode) > 0) {
2779                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2780                                                       inode);
2781                 if (ret)
2782                         goto out_put;
2783         }
2784
2785         spin_lock(&block_group->lock);
2786         if (block_group->cached != BTRFS_CACHE_FINISHED) {
2787                 /* We're not cached, don't bother trying to write stuff out */
2788                 dcs = BTRFS_DC_WRITTEN;
2789                 spin_unlock(&block_group->lock);
2790                 goto out_put;
2791         }
2792         spin_unlock(&block_group->lock);
2793
2794         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2795         if (!num_pages)
2796                 num_pages = 1;
2797
2798         /*
2799          * Just to make absolutely sure we have enough space, we're going to
2800          * preallocate 12 pages worth of space for each block group.  In
2801          * practice we ought to use at most 8, but we need extra space so we can
2802          * add our header and have a terminator between the extents and the
2803          * bitmaps.
2804          */
2805         num_pages *= 16;
2806         num_pages *= PAGE_CACHE_SIZE;
2807
2808         ret = btrfs_check_data_free_space(inode, num_pages);
2809         if (ret)
2810                 goto out_put;
2811
2812         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2813                                               num_pages, num_pages,
2814                                               &alloc_hint);
2815         if (!ret)
2816                 dcs = BTRFS_DC_SETUP;
2817         btrfs_free_reserved_data_space(inode, num_pages);
2818
2819 out_put:
2820         iput(inode);
2821 out_free:
2822         btrfs_release_path(path);
2823 out:
2824         spin_lock(&block_group->lock);
2825         if (!ret)
2826                 block_group->cache_generation = trans->transid;
2827         block_group->disk_cache_state = dcs;
2828         spin_unlock(&block_group->lock);
2829
2830         return ret;
2831 }
2832
2833 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2834                                    struct btrfs_root *root)
2835 {
2836         struct btrfs_block_group_cache *cache;
2837         int err = 0;
2838         struct btrfs_path *path;
2839         u64 last = 0;
2840
2841         path = btrfs_alloc_path();
2842         if (!path)
2843                 return -ENOMEM;
2844
2845 again:
2846         while (1) {
2847                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2848                 while (cache) {
2849                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2850                                 break;
2851                         cache = next_block_group(root, cache);
2852                 }
2853                 if (!cache) {
2854                         if (last == 0)
2855                                 break;
2856                         last = 0;
2857                         continue;
2858                 }
2859                 err = cache_save_setup(cache, trans, path);
2860                 last = cache->key.objectid + cache->key.offset;
2861                 btrfs_put_block_group(cache);
2862         }
2863
2864         while (1) {
2865                 if (last == 0) {
2866                         err = btrfs_run_delayed_refs(trans, root,
2867                                                      (unsigned long)-1);
2868                         BUG_ON(err);
2869                 }
2870
2871                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2872                 while (cache) {
2873                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
2874                                 btrfs_put_block_group(cache);
2875                                 goto again;
2876                         }
2877
2878                         if (cache->dirty)
2879                                 break;
2880                         cache = next_block_group(root, cache);
2881                 }
2882                 if (!cache) {
2883                         if (last == 0)
2884                                 break;
2885                         last = 0;
2886                         continue;
2887                 }
2888
2889                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
2890                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
2891                 cache->dirty = 0;
2892                 last = cache->key.objectid + cache->key.offset;
2893
2894                 err = write_one_cache_group(trans, root, path, cache);
2895                 BUG_ON(err);
2896                 btrfs_put_block_group(cache);
2897         }
2898
2899         while (1) {
2900                 /*
2901                  * I don't think this is needed since we're just marking our
2902                  * preallocated extent as written, but just in case it can't
2903                  * hurt.
2904                  */
2905                 if (last == 0) {
2906                         err = btrfs_run_delayed_refs(trans, root,
2907                                                      (unsigned long)-1);
2908                         BUG_ON(err);
2909                 }
2910
2911                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2912                 while (cache) {
2913                         /*
2914                          * Really this shouldn't happen, but it could if we
2915                          * couldn't write the entire preallocated extent and
2916                          * splitting the extent resulted in a new block.
2917                          */
2918                         if (cache->dirty) {
2919                                 btrfs_put_block_group(cache);
2920                                 goto again;
2921                         }
2922                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2923                                 break;
2924                         cache = next_block_group(root, cache);
2925                 }
2926                 if (!cache) {
2927                         if (last == 0)
2928                                 break;
2929                         last = 0;
2930                         continue;
2931                 }
2932
2933                 btrfs_write_out_cache(root, trans, cache, path);
2934
2935                 /*
2936                  * If we didn't have an error then the cache state is still
2937                  * NEED_WRITE, so we can set it to WRITTEN.
2938                  */
2939                 if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2940                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
2941                 last = cache->key.objectid + cache->key.offset;
2942                 btrfs_put_block_group(cache);
2943         }
2944
2945         btrfs_free_path(path);
2946         return 0;
2947 }
2948
2949 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
2950 {
2951         struct btrfs_block_group_cache *block_group;
2952         int readonly = 0;
2953
2954         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
2955         if (!block_group || block_group->ro)
2956                 readonly = 1;
2957         if (block_group)
2958                 btrfs_put_block_group(block_group);
2959         return readonly;
2960 }
2961
2962 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
2963                              u64 total_bytes, u64 bytes_used,
2964                              struct btrfs_space_info **space_info)
2965 {
2966         struct btrfs_space_info *found;
2967         int i;
2968         int factor;
2969
2970         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
2971                      BTRFS_BLOCK_GROUP_RAID10))
2972                 factor = 2;
2973         else
2974                 factor = 1;
2975
2976         found = __find_space_info(info, flags);
2977         if (found) {
2978                 spin_lock(&found->lock);
2979                 found->total_bytes += total_bytes;
2980                 found->disk_total += total_bytes * factor;
2981                 found->bytes_used += bytes_used;
2982                 found->disk_used += bytes_used * factor;
2983                 found->full = 0;
2984                 spin_unlock(&found->lock);
2985                 *space_info = found;
2986                 return 0;
2987         }
2988         found = kzalloc(sizeof(*found), GFP_NOFS);
2989         if (!found)
2990                 return -ENOMEM;
2991
2992         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
2993                 INIT_LIST_HEAD(&found->block_groups[i]);
2994         init_rwsem(&found->groups_sem);
2995         spin_lock_init(&found->lock);
2996         found->flags = flags & (BTRFS_BLOCK_GROUP_DATA |
2997                                 BTRFS_BLOCK_GROUP_SYSTEM |
2998                                 BTRFS_BLOCK_GROUP_METADATA);
2999         found->total_bytes = total_bytes;
3000         found->disk_total = total_bytes * factor;
3001         found->bytes_used = bytes_used;
3002         found->disk_used = bytes_used * factor;
3003         found->bytes_pinned = 0;
3004         found->bytes_reserved = 0;
3005         found->bytes_readonly = 0;
3006         found->bytes_may_use = 0;
3007         found->full = 0;
3008         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3009         found->chunk_alloc = 0;
3010         found->flush = 0;
3011         init_waitqueue_head(&found->wait);
3012         *space_info = found;
3013         list_add_rcu(&found->list, &info->space_info);
3014         return 0;
3015 }
3016
3017 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3018 {
3019         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
3020                                    BTRFS_BLOCK_GROUP_RAID1 |
3021                                    BTRFS_BLOCK_GROUP_RAID10 |
3022                                    BTRFS_BLOCK_GROUP_DUP);
3023         if (extra_flags) {
3024                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3025                         fs_info->avail_data_alloc_bits |= extra_flags;
3026                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
3027                         fs_info->avail_metadata_alloc_bits |= extra_flags;
3028                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3029                         fs_info->avail_system_alloc_bits |= extra_flags;
3030         }
3031 }
3032
3033 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3034 {
3035         /*
3036          * we add in the count of missing devices because we want
3037          * to make sure that any RAID levels on a degraded FS
3038          * continue to be honored.
3039          */
3040         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3041                 root->fs_info->fs_devices->missing_devices;
3042
3043         if (num_devices == 1)
3044                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
3045         if (num_devices < 4)
3046                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3047
3048         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
3049             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3050                       BTRFS_BLOCK_GROUP_RAID10))) {
3051                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
3052         }
3053
3054         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
3055             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
3056                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
3057         }
3058
3059         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
3060             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
3061              (flags & BTRFS_BLOCK_GROUP_RAID10) |
3062              (flags & BTRFS_BLOCK_GROUP_DUP)))
3063                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
3064         return flags;
3065 }
3066
3067 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3068 {
3069         if (flags & BTRFS_BLOCK_GROUP_DATA)
3070                 flags |= root->fs_info->avail_data_alloc_bits &
3071                          root->fs_info->data_alloc_profile;
3072         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3073                 flags |= root->fs_info->avail_system_alloc_bits &
3074                          root->fs_info->system_alloc_profile;
3075         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3076                 flags |= root->fs_info->avail_metadata_alloc_bits &
3077                          root->fs_info->metadata_alloc_profile;
3078         return btrfs_reduce_alloc_profile(root, flags);
3079 }
3080
3081 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3082 {
3083         u64 flags;
3084
3085         if (data)
3086                 flags = BTRFS_BLOCK_GROUP_DATA;
3087         else if (root == root->fs_info->chunk_root)
3088                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3089         else
3090                 flags = BTRFS_BLOCK_GROUP_METADATA;
3091
3092         return get_alloc_profile(root, flags);
3093 }
3094
3095 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
3096 {
3097         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
3098                                                        BTRFS_BLOCK_GROUP_DATA);
3099 }
3100
3101 /*
3102  * This will check the space that the inode allocates from to make sure we have
3103  * enough space for bytes.
3104  */
3105 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3106 {
3107         struct btrfs_space_info *data_sinfo;
3108         struct btrfs_root *root = BTRFS_I(inode)->root;
3109         u64 used;
3110         int ret = 0, committed = 0, alloc_chunk = 1;
3111
3112         /* make sure bytes are sectorsize aligned */
3113         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3114
3115         if (root == root->fs_info->tree_root ||
3116             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3117                 alloc_chunk = 0;
3118                 committed = 1;
3119         }
3120
3121         data_sinfo = BTRFS_I(inode)->space_info;
3122         if (!data_sinfo)
3123                 goto alloc;
3124
3125 again:
3126         /* make sure we have enough space to handle the data first */
3127         spin_lock(&data_sinfo->lock);
3128         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3129                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3130                 data_sinfo->bytes_may_use;
3131
3132         if (used + bytes > data_sinfo->total_bytes) {
3133                 struct btrfs_trans_handle *trans;
3134
3135                 /*
3136                  * if we don't have enough free bytes in this space then we need
3137                  * to alloc a new chunk.
3138                  */
3139                 if (!data_sinfo->full && alloc_chunk) {
3140                         u64 alloc_target;
3141
3142                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3143                         spin_unlock(&data_sinfo->lock);
3144 alloc:
3145                         alloc_target = btrfs_get_alloc_profile(root, 1);
3146                         trans = btrfs_join_transaction(root);
3147                         if (IS_ERR(trans))
3148                                 return PTR_ERR(trans);
3149
3150                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3151                                              bytes + 2 * 1024 * 1024,
3152                                              alloc_target,
3153                                              CHUNK_ALLOC_NO_FORCE);
3154                         btrfs_end_transaction(trans, root);
3155                         if (ret < 0) {
3156                                 if (ret != -ENOSPC)
3157                                         return ret;
3158                                 else
3159                                         goto commit_trans;
3160                         }
3161
3162                         if (!data_sinfo) {
3163                                 btrfs_set_inode_space_info(root, inode);
3164                                 data_sinfo = BTRFS_I(inode)->space_info;
3165                         }
3166                         goto again;
3167                 }
3168
3169                 /*
3170                  * If we have less pinned bytes than we want to allocate then
3171                  * don't bother committing the transaction, it won't help us.
3172                  */
3173                 if (data_sinfo->bytes_pinned < bytes)
3174                         committed = 1;
3175                 spin_unlock(&data_sinfo->lock);
3176
3177                 /* commit the current transaction and try again */
3178 commit_trans:
3179                 if (!committed &&
3180                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3181                         committed = 1;
3182                         trans = btrfs_join_transaction(root);
3183                         if (IS_ERR(trans))
3184                                 return PTR_ERR(trans);
3185                         ret = btrfs_commit_transaction(trans, root);
3186                         if (ret)
3187                                 return ret;
3188                         goto again;
3189                 }
3190
3191                 return -ENOSPC;
3192         }
3193         data_sinfo->bytes_may_use += bytes;
3194         spin_unlock(&data_sinfo->lock);
3195
3196         return 0;
3197 }
3198
3199 /*
3200  * Called if we need to clear a data reservation for this inode.
3201  */
3202 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3203 {
3204         struct btrfs_root *root = BTRFS_I(inode)->root;
3205         struct btrfs_space_info *data_sinfo;
3206
3207         /* make sure bytes are sectorsize aligned */
3208         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3209
3210         data_sinfo = BTRFS_I(inode)->space_info;
3211         spin_lock(&data_sinfo->lock);
3212         data_sinfo->bytes_may_use -= bytes;
3213         spin_unlock(&data_sinfo->lock);
3214 }
3215
3216 static void force_metadata_allocation(struct btrfs_fs_info *info)
3217 {
3218         struct list_head *head = &info->space_info;
3219         struct btrfs_space_info *found;
3220
3221         rcu_read_lock();
3222         list_for_each_entry_rcu(found, head, list) {
3223                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3224                         found->force_alloc = CHUNK_ALLOC_FORCE;
3225         }
3226         rcu_read_unlock();
3227 }
3228
3229 static int should_alloc_chunk(struct btrfs_root *root,
3230                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3231                               int force)
3232 {
3233         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3234         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3235         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3236         u64 thresh;
3237
3238         if (force == CHUNK_ALLOC_FORCE)
3239                 return 1;
3240
3241         /*
3242          * We need to take into account the global rsv because for all intents
3243          * and purposes it's used space.  Don't worry about locking the
3244          * global_rsv, it doesn't change except when the transaction commits.
3245          */
3246         num_allocated += global_rsv->size;
3247
3248         /*
3249          * in limited mode, we want to have some free space up to
3250          * about 1% of the FS size.
3251          */
3252         if (force == CHUNK_ALLOC_LIMITED) {
3253                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3254                 thresh = max_t(u64, 64 * 1024 * 1024,
3255                                div_factor_fine(thresh, 1));
3256
3257                 if (num_bytes - num_allocated < thresh)
3258                         return 1;
3259         }
3260
3261         /*
3262          * we have two similar checks here, one based on percentage
3263          * and once based on a hard number of 256MB.  The idea
3264          * is that if we have a good amount of free
3265          * room, don't allocate a chunk.  A good mount is
3266          * less than 80% utilized of the chunks we have allocated,
3267          * or more than 256MB free
3268          */
3269         if (num_allocated + alloc_bytes + 256 * 1024 * 1024 < num_bytes)
3270                 return 0;
3271
3272         if (num_allocated + alloc_bytes < div_factor(num_bytes, 8))
3273                 return 0;
3274
3275         thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3276
3277         /* 256MB or 5% of the FS */
3278         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 5));
3279
3280         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 3))
3281                 return 0;
3282         return 1;
3283 }
3284
3285 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3286                           struct btrfs_root *extent_root, u64 alloc_bytes,
3287                           u64 flags, int force)
3288 {
3289         struct btrfs_space_info *space_info;
3290         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3291         int wait_for_alloc = 0;
3292         int ret = 0;
3293
3294         flags = btrfs_reduce_alloc_profile(extent_root, flags);
3295
3296         space_info = __find_space_info(extent_root->fs_info, flags);
3297         if (!space_info) {
3298                 ret = update_space_info(extent_root->fs_info, flags,
3299                                         0, 0, &space_info);
3300                 BUG_ON(ret);
3301         }
3302         BUG_ON(!space_info);
3303
3304 again:
3305         spin_lock(&space_info->lock);
3306         if (space_info->force_alloc)
3307                 force = space_info->force_alloc;
3308         if (space_info->full) {
3309                 spin_unlock(&space_info->lock);
3310                 return 0;
3311         }
3312
3313         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3314                 spin_unlock(&space_info->lock);
3315                 return 0;
3316         } else if (space_info->chunk_alloc) {
3317                 wait_for_alloc = 1;
3318         } else {
3319                 space_info->chunk_alloc = 1;
3320         }
3321
3322         spin_unlock(&space_info->lock);
3323
3324         mutex_lock(&fs_info->chunk_mutex);
3325
3326         /*
3327          * The chunk_mutex is held throughout the entirety of a chunk
3328          * allocation, so once we've acquired the chunk_mutex we know that the
3329          * other guy is done and we need to recheck and see if we should
3330          * allocate.
3331          */
3332         if (wait_for_alloc) {
3333                 mutex_unlock(&fs_info->chunk_mutex);
3334                 wait_for_alloc = 0;
3335                 goto again;
3336         }
3337
3338         /*
3339          * If we have mixed data/metadata chunks we want to make sure we keep
3340          * allocating mixed chunks instead of individual chunks.
3341          */
3342         if (btrfs_mixed_space_info(space_info))
3343                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3344
3345         /*
3346          * if we're doing a data chunk, go ahead and make sure that
3347          * we keep a reasonable number of metadata chunks allocated in the
3348          * FS as well.
3349          */
3350         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3351                 fs_info->data_chunk_allocations++;
3352                 if (!(fs_info->data_chunk_allocations %
3353                       fs_info->metadata_ratio))
3354                         force_metadata_allocation(fs_info);
3355         }
3356
3357         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3358         if (ret < 0 && ret != -ENOSPC)
3359                 goto out;
3360
3361         spin_lock(&space_info->lock);
3362         if (ret)
3363                 space_info->full = 1;
3364         else
3365                 ret = 1;
3366
3367         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3368         space_info->chunk_alloc = 0;
3369         spin_unlock(&space_info->lock);
3370 out:
3371         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3372         return ret;
3373 }
3374
3375 /*
3376  * shrink metadata reservation for delalloc
3377  */
3378 static int shrink_delalloc(struct btrfs_root *root, u64 to_reclaim,
3379                            bool wait_ordered)
3380 {
3381         struct btrfs_block_rsv *block_rsv;
3382         struct btrfs_space_info *space_info;
3383         struct btrfs_trans_handle *trans;
3384         u64 reserved;
3385         u64 max_reclaim;
3386         u64 reclaimed = 0;
3387         long time_left;
3388         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3389         int loops = 0;
3390         unsigned long progress;
3391
3392         trans = (struct btrfs_trans_handle *)current->journal_info;
3393         block_rsv = &root->fs_info->delalloc_block_rsv;
3394         space_info = block_rsv->space_info;
3395
3396         smp_mb();
3397         reserved = space_info->bytes_may_use;
3398         progress = space_info->reservation_progress;
3399
3400         if (reserved == 0)
3401                 return 0;
3402
3403         smp_mb();
3404         if (root->fs_info->delalloc_bytes == 0) {
3405                 if (trans)
3406                         return 0;
3407                 btrfs_wait_ordered_extents(root, 0, 0);
3408                 return 0;
3409         }
3410
3411         max_reclaim = min(reserved, to_reclaim);
3412         nr_pages = max_t(unsigned long, nr_pages,
3413                          max_reclaim >> PAGE_CACHE_SHIFT);
3414         while (loops < 1024) {
3415                 /* have the flusher threads jump in and do some IO */
3416                 smp_mb();
3417                 nr_pages = min_t(unsigned long, nr_pages,
3418                        root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
3419                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages);
3420
3421                 spin_lock(&space_info->lock);
3422                 if (reserved > space_info->bytes_may_use)
3423                         reclaimed += reserved - space_info->bytes_may_use;
3424                 reserved = space_info->bytes_may_use;
3425                 spin_unlock(&space_info->lock);
3426
3427                 loops++;
3428
3429                 if (reserved == 0 || reclaimed >= max_reclaim)
3430                         break;
3431
3432                 if (trans && trans->transaction->blocked)
3433                         return -EAGAIN;
3434
3435                 if (wait_ordered && !trans) {
3436                         btrfs_wait_ordered_extents(root, 0, 0);
3437                 } else {
3438                         time_left = schedule_timeout_interruptible(1);
3439
3440                         /* We were interrupted, exit */
3441                         if (time_left)
3442                                 break;
3443                 }
3444
3445                 /* we've kicked the IO a few times, if anything has been freed,
3446                  * exit.  There is no sense in looping here for a long time
3447                  * when we really need to commit the transaction, or there are
3448                  * just too many writers without enough free space
3449                  */
3450
3451                 if (loops > 3) {
3452                         smp_mb();
3453                         if (progress != space_info->reservation_progress)
3454                                 break;
3455                 }
3456
3457         }
3458
3459         return reclaimed >= to_reclaim;
3460 }
3461
3462 /**
3463  * maybe_commit_transaction - possibly commit the transaction if its ok to
3464  * @root - the root we're allocating for
3465  * @bytes - the number of bytes we want to reserve
3466  * @force - force the commit
3467  *
3468  * This will check to make sure that committing the transaction will actually
3469  * get us somewhere and then commit the transaction if it does.  Otherwise it
3470  * will return -ENOSPC.
3471  */
3472 static int may_commit_transaction(struct btrfs_root *root,
3473                                   struct btrfs_space_info *space_info,
3474                                   u64 bytes, int force)
3475 {
3476         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
3477         struct btrfs_trans_handle *trans;
3478
3479         trans = (struct btrfs_trans_handle *)current->journal_info;
3480         if (trans)
3481                 return -EAGAIN;
3482
3483         if (force)
3484                 goto commit;
3485
3486         /* See if there is enough pinned space to make this reservation */
3487         spin_lock(&space_info->lock);
3488         if (space_info->bytes_pinned >= bytes) {
3489                 spin_unlock(&space_info->lock);
3490                 goto commit;
3491         }
3492         spin_unlock(&space_info->lock);
3493
3494         /*
3495          * See if there is some space in the delayed insertion reservation for
3496          * this reservation.
3497          */
3498         if (space_info != delayed_rsv->space_info)
3499                 return -ENOSPC;
3500
3501         spin_lock(&delayed_rsv->lock);
3502         if (delayed_rsv->size < bytes) {
3503                 spin_unlock(&delayed_rsv->lock);
3504                 return -ENOSPC;
3505         }
3506         spin_unlock(&delayed_rsv->lock);
3507
3508 commit:
3509         trans = btrfs_join_transaction(root);
3510         if (IS_ERR(trans))
3511                 return -ENOSPC;
3512
3513         return btrfs_commit_transaction(trans, root);
3514 }
3515
3516 /**
3517  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
3518  * @root - the root we're allocating for
3519  * @block_rsv - the block_rsv we're allocating for
3520  * @orig_bytes - the number of bytes we want
3521  * @flush - wether or not we can flush to make our reservation
3522  *
3523  * This will reserve orgi_bytes number of bytes from the space info associated
3524  * with the block_rsv.  If there is not enough space it will make an attempt to
3525  * flush out space to make room.  It will do this by flushing delalloc if
3526  * possible or committing the transaction.  If flush is 0 then no attempts to
3527  * regain reservations will be made and this will fail if there is not enough
3528  * space already.
3529  */
3530 static int reserve_metadata_bytes(struct btrfs_root *root,
3531                                   struct btrfs_block_rsv *block_rsv,
3532                                   u64 orig_bytes, int flush)
3533 {
3534         struct btrfs_space_info *space_info = block_rsv->space_info;
3535         u64 used;
3536         u64 num_bytes = orig_bytes;
3537         int retries = 0;
3538         int ret = 0;
3539         bool committed = false;
3540         bool flushing = false;
3541         bool wait_ordered = false;
3542
3543 again:
3544         ret = 0;
3545         spin_lock(&space_info->lock);
3546         /*
3547          * We only want to wait if somebody other than us is flushing and we are
3548          * actually alloed to flush.
3549          */
3550         while (flush && !flushing && space_info->flush) {
3551                 spin_unlock(&space_info->lock);
3552                 /*
3553                  * If we have a trans handle we can't wait because the flusher
3554                  * may have to commit the transaction, which would mean we would
3555                  * deadlock since we are waiting for the flusher to finish, but
3556                  * hold the current transaction open.
3557                  */
3558                 if (current->journal_info)
3559                         return -EAGAIN;
3560                 ret = wait_event_interruptible(space_info->wait,
3561                                                !space_info->flush);
3562                 /* Must have been interrupted, return */
3563                 if (ret)
3564                         return -EINTR;
3565
3566                 spin_lock(&space_info->lock);
3567         }
3568
3569         ret = -ENOSPC;
3570         used = space_info->bytes_used + space_info->bytes_reserved +
3571                 space_info->bytes_pinned + space_info->bytes_readonly +
3572                 space_info->bytes_may_use;
3573
3574         /*
3575          * The idea here is that we've not already over-reserved the block group
3576          * then we can go ahead and save our reservation first and then start
3577          * flushing if we need to.  Otherwise if we've already overcommitted
3578          * lets start flushing stuff first and then come back and try to make
3579          * our reservation.
3580          */
3581         if (used <= space_info->total_bytes) {
3582                 if (used + orig_bytes <= space_info->total_bytes) {
3583                         space_info->bytes_may_use += orig_bytes;
3584                         ret = 0;
3585                 } else {
3586                         /*
3587                          * Ok set num_bytes to orig_bytes since we aren't
3588                          * overocmmitted, this way we only try and reclaim what
3589                          * we need.
3590                          */
3591                         num_bytes = orig_bytes;
3592                 }
3593         } else {
3594                 /*
3595                  * Ok we're over committed, set num_bytes to the overcommitted
3596                  * amount plus the amount of bytes that we need for this
3597                  * reservation.
3598                  */
3599                 wait_ordered = true;
3600                 num_bytes = used - space_info->total_bytes +
3601                         (orig_bytes * (retries + 1));
3602         }
3603
3604         if (ret) {
3605                 u64 profile = btrfs_get_alloc_profile(root, 0);
3606                 u64 avail;
3607
3608                 /*
3609                  * If we have a lot of space that's pinned, don't bother doing
3610                  * the overcommit dance yet and just commit the transaction.
3611                  */
3612                 avail = (space_info->total_bytes - space_info->bytes_used) * 8;
3613                 do_div(avail, 10);
3614                 if (space_info->bytes_pinned >= avail && flush && !committed) {
3615                         space_info->flush = 1;
3616                         flushing = true;
3617                         spin_unlock(&space_info->lock);
3618                         ret = may_commit_transaction(root, space_info,
3619                                                      orig_bytes, 1);
3620                         if (ret)
3621                                 goto out;
3622                         committed = true;
3623                         goto again;
3624                 }
3625
3626                 spin_lock(&root->fs_info->free_chunk_lock);
3627                 avail = root->fs_info->free_chunk_space;
3628
3629                 /*
3630                  * If we have dup, raid1 or raid10 then only half of the free
3631                  * space is actually useable.
3632                  */
3633                 if (profile & (BTRFS_BLOCK_GROUP_DUP |
3634                                BTRFS_BLOCK_GROUP_RAID1 |
3635                                BTRFS_BLOCK_GROUP_RAID10))
3636                         avail >>= 1;
3637
3638                 /*
3639                  * If we aren't flushing don't let us overcommit too much, say
3640                  * 1/8th of the space.  If we can flush, let it overcommit up to
3641                  * 1/2 of the space.
3642                  */
3643                 if (flush)
3644                         avail >>= 3;
3645                 else
3646                         avail >>= 1;
3647                  spin_unlock(&root->fs_info->free_chunk_lock);
3648
3649                 if (used + num_bytes < space_info->total_bytes + avail) {
3650                         space_info->bytes_may_use += orig_bytes;
3651                         ret = 0;
3652                 } else {
3653                         wait_ordered = true;
3654                 }
3655         }
3656
3657         /*
3658          * Couldn't make our reservation, save our place so while we're trying
3659          * to reclaim space we can actually use it instead of somebody else
3660          * stealing it from us.
3661          */
3662         if (ret && flush) {
3663                 flushing = true;
3664                 space_info->flush = 1;
3665         }
3666
3667         spin_unlock(&space_info->lock);
3668
3669         if (!ret || !flush)
3670                 goto out;
3671
3672         /*
3673          * We do synchronous shrinking since we don't actually unreserve
3674          * metadata until after the IO is completed.
3675          */
3676         ret = shrink_delalloc(root, num_bytes, wait_ordered);
3677         if (ret < 0)
3678                 goto out;
3679
3680         ret = 0;
3681
3682         /*
3683          * So if we were overcommitted it's possible that somebody else flushed
3684          * out enough space and we simply didn't have enough space to reclaim,
3685          * so go back around and try again.
3686          */
3687         if (retries < 2) {
3688                 wait_ordered = true;
3689                 retries++;
3690                 goto again;
3691         }
3692
3693         ret = -ENOSPC;
3694         if (committed)
3695                 goto out;
3696
3697         ret = may_commit_transaction(root, space_info, orig_bytes, 0);
3698         if (!ret) {
3699                 committed = true;
3700                 goto again;
3701         }
3702
3703 out:
3704         if (flushing) {
3705                 spin_lock(&space_info->lock);
3706                 space_info->flush = 0;
3707                 wake_up_all(&space_info->wait);
3708                 spin_unlock(&space_info->lock);
3709         }
3710         return ret;
3711 }
3712
3713 static struct btrfs_block_rsv *get_block_rsv(struct btrfs_trans_handle *trans,
3714                                              struct btrfs_root *root)
3715 {
3716         struct btrfs_block_rsv *block_rsv = NULL;
3717
3718         if (root->ref_cows || root == root->fs_info->csum_root)
3719                 block_rsv = trans->block_rsv;
3720
3721         if (!block_rsv)
3722                 block_rsv = root->block_rsv;
3723
3724         if (!block_rsv)
3725                 block_rsv = &root->fs_info->empty_block_rsv;
3726
3727         return block_rsv;
3728 }
3729
3730 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
3731                                u64 num_bytes)
3732 {
3733         int ret = -ENOSPC;
3734         spin_lock(&block_rsv->lock);
3735         if (block_rsv->reserved >= num_bytes) {
3736                 block_rsv->reserved -= num_bytes;
3737                 if (block_rsv->reserved < block_rsv->size)
3738                         block_rsv->full = 0;
3739                 ret = 0;
3740         }
3741         spin_unlock(&block_rsv->lock);
3742         return ret;
3743 }
3744
3745 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
3746                                 u64 num_bytes, int update_size)
3747 {
3748         spin_lock(&block_rsv->lock);
3749         block_rsv->reserved += num_bytes;
3750         if (update_size)
3751                 block_rsv->size += num_bytes;
3752         else if (block_rsv->reserved >= block_rsv->size)
3753                 block_rsv->full = 1;
3754         spin_unlock(&block_rsv->lock);
3755 }
3756
3757 static void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv,
3758                                     struct btrfs_block_rsv *dest, u64 num_bytes)
3759 {
3760         struct btrfs_space_info *space_info = block_rsv->space_info;
3761
3762         spin_lock(&block_rsv->lock);
3763         if (num_bytes == (u64)-1)
3764                 num_bytes = block_rsv->size;
3765         block_rsv->size -= num_bytes;
3766         if (block_rsv->reserved >= block_rsv->size) {
3767                 num_bytes = block_rsv->reserved - block_rsv->size;
3768                 block_rsv->reserved = block_rsv->size;
3769                 block_rsv->full = 1;
3770         } else {
3771                 num_bytes = 0;
3772         }
3773         spin_unlock(&block_rsv->lock);
3774
3775         if (num_bytes > 0) {
3776                 if (dest) {
3777                         spin_lock(&dest->lock);
3778                         if (!dest->full) {
3779                                 u64 bytes_to_add;
3780
3781                                 bytes_to_add = dest->size - dest->reserved;
3782                                 bytes_to_add = min(num_bytes, bytes_to_add);
3783                                 dest->reserved += bytes_to_add;
3784                                 if (dest->reserved >= dest->size)
3785                                         dest->full = 1;
3786                                 num_bytes -= bytes_to_add;
3787                         }
3788                         spin_unlock(&dest->lock);
3789                 }
3790                 if (num_bytes) {
3791                         spin_lock(&space_info->lock);
3792                         space_info->bytes_may_use -= num_bytes;
3793                         space_info->reservation_progress++;
3794                         spin_unlock(&space_info->lock);
3795                 }
3796         }
3797 }
3798
3799 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
3800                                    struct btrfs_block_rsv *dst, u64 num_bytes)
3801 {
3802         int ret;
3803
3804         ret = block_rsv_use_bytes(src, num_bytes);
3805         if (ret)
3806                 return ret;
3807
3808         block_rsv_add_bytes(dst, num_bytes, 1);
3809         return 0;
3810 }
3811
3812 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
3813 {
3814         memset(rsv, 0, sizeof(*rsv));
3815         spin_lock_init(&rsv->lock);
3816 }
3817
3818 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
3819 {
3820         struct btrfs_block_rsv *block_rsv;
3821         struct btrfs_fs_info *fs_info = root->fs_info;
3822
3823         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
3824         if (!block_rsv)
3825                 return NULL;
3826
3827         btrfs_init_block_rsv(block_rsv);
3828         block_rsv->space_info = __find_space_info(fs_info,
3829                                                   BTRFS_BLOCK_GROUP_METADATA);
3830         return block_rsv;
3831 }
3832
3833 void btrfs_free_block_rsv(struct btrfs_root *root,
3834                           struct btrfs_block_rsv *rsv)
3835 {
3836         btrfs_block_rsv_release(root, rsv, (u64)-1);
3837         kfree(rsv);
3838 }
3839
3840 static inline int __block_rsv_add(struct btrfs_root *root,
3841                                   struct btrfs_block_rsv *block_rsv,
3842                                   u64 num_bytes, int flush)
3843 {
3844         int ret;
3845
3846         if (num_bytes == 0)
3847                 return 0;
3848
3849         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
3850         if (!ret) {
3851                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
3852                 return 0;
3853         }
3854
3855         return ret;
3856 }
3857
3858 int btrfs_block_rsv_add(struct btrfs_root *root,
3859                         struct btrfs_block_rsv *block_rsv,
3860                         u64 num_bytes)
3861 {
3862         return __block_rsv_add(root, block_rsv, num_bytes, 1);
3863 }
3864
3865 int btrfs_block_rsv_add_noflush(struct btrfs_root *root,
3866                                 struct btrfs_block_rsv *block_rsv,
3867                                 u64 num_bytes)
3868 {
3869         return __block_rsv_add(root, block_rsv, num_bytes, 0);
3870 }
3871
3872 int btrfs_block_rsv_check(struct btrfs_root *root,
3873                           struct btrfs_block_rsv *block_rsv, int min_factor)
3874 {
3875         u64 num_bytes = 0;
3876         int ret = -ENOSPC;
3877
3878         if (!block_rsv)
3879                 return 0;
3880
3881         spin_lock(&block_rsv->lock);
3882         num_bytes = div_factor(block_rsv->size, min_factor);
3883         if (block_rsv->reserved >= num_bytes)
3884                 ret = 0;
3885         spin_unlock(&block_rsv->lock);
3886
3887         return ret;
3888 }
3889
3890 static inline int __btrfs_block_rsv_refill(struct btrfs_root *root,
3891                                            struct btrfs_block_rsv *block_rsv,
3892                                            u64 min_reserved, int flush)
3893 {
3894         u64 num_bytes = 0;
3895         int ret = -ENOSPC;
3896
3897         if (!block_rsv)
3898                 return 0;
3899
3900         spin_lock(&block_rsv->lock);
3901         num_bytes = min_reserved;
3902         if (block_rsv->reserved >= num_bytes)
3903                 ret = 0;
3904         else
3905                 num_bytes -= block_rsv->reserved;
3906         spin_unlock(&block_rsv->lock);
3907
3908         if (!ret)
3909                 return 0;
3910
3911         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
3912         if (!ret) {
3913                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
3914                 return 0;
3915         }
3916
3917         return ret;
3918 }
3919
3920 int btrfs_block_rsv_refill(struct btrfs_root *root,
3921                            struct btrfs_block_rsv *block_rsv,
3922                            u64 min_reserved)
3923 {
3924         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 1);
3925 }
3926
3927 int btrfs_block_rsv_refill_noflush(struct btrfs_root *root,
3928                                    struct btrfs_block_rsv *block_rsv,
3929                                    u64 min_reserved)
3930 {
3931         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 0);
3932 }
3933
3934 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
3935                             struct btrfs_block_rsv *dst_rsv,
3936                             u64 num_bytes)
3937 {
3938         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3939 }
3940
3941 void btrfs_block_rsv_release(struct btrfs_root *root,
3942                              struct btrfs_block_rsv *block_rsv,
3943                              u64 num_bytes)
3944 {
3945         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3946         if (global_rsv->full || global_rsv == block_rsv ||
3947             block_rsv->space_info != global_rsv->space_info)
3948                 global_rsv = NULL;
3949         block_rsv_release_bytes(block_rsv, global_rsv, num_bytes);
3950 }
3951
3952 /*
3953  * helper to calculate size of global block reservation.
3954  * the desired value is sum of space used by extent tree,
3955  * checksum tree and root tree
3956  */
3957 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
3958 {
3959         struct btrfs_space_info *sinfo;
3960         u64 num_bytes;
3961         u64 meta_used;
3962         u64 data_used;
3963         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
3964
3965         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
3966         spin_lock(&sinfo->lock);
3967         data_used = sinfo->bytes_used;
3968         spin_unlock(&sinfo->lock);
3969
3970         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3971         spin_lock(&sinfo->lock);
3972         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
3973                 data_used = 0;
3974         meta_used = sinfo->bytes_used;
3975         spin_unlock(&sinfo->lock);
3976
3977         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
3978                     csum_size * 2;
3979         num_bytes += div64_u64(data_used + meta_used, 50);
3980
3981         if (num_bytes * 3 > meta_used)
3982                 num_bytes = div64_u64(meta_used, 3);
3983
3984         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
3985 }
3986
3987 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
3988 {
3989         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
3990         struct btrfs_space_info *sinfo = block_rsv->space_info;
3991         u64 num_bytes;
3992
3993         num_bytes = calc_global_metadata_size(fs_info);
3994
3995         spin_lock(&block_rsv->lock);
3996         spin_lock(&sinfo->lock);
3997
3998         block_rsv->size = num_bytes;
3999
4000         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4001                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4002                     sinfo->bytes_may_use;
4003
4004         if (sinfo->total_bytes > num_bytes) {
4005                 num_bytes = sinfo->total_bytes - num_bytes;
4006                 block_rsv->reserved += num_bytes;
4007                 sinfo->bytes_may_use += num_bytes;
4008         }
4009
4010         if (block_rsv->reserved >= block_rsv->size) {
4011                 num_bytes = block_rsv->reserved - block_rsv->size;
4012                 sinfo->bytes_may_use -= num_bytes;
4013                 sinfo->reservation_progress++;
4014                 block_rsv->reserved = block_rsv->size;
4015                 block_rsv->full = 1;
4016         }
4017
4018         spin_unlock(&sinfo->lock);
4019         spin_unlock(&block_rsv->lock);
4020 }
4021
4022 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4023 {
4024         struct btrfs_space_info *space_info;
4025
4026         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4027         fs_info->chunk_block_rsv.space_info = space_info;
4028
4029         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4030         fs_info->global_block_rsv.space_info = space_info;
4031         fs_info->delalloc_block_rsv.space_info = space_info;
4032         fs_info->trans_block_rsv.space_info = space_info;
4033         fs_info->empty_block_rsv.space_info = space_info;
4034         fs_info->delayed_block_rsv.space_info = space_info;
4035
4036         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4037         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4038         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4039         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4040         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4041
4042         update_global_block_rsv(fs_info);
4043 }
4044
4045 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4046 {
4047         block_rsv_release_bytes(&fs_info->global_block_rsv, NULL, (u64)-1);
4048         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4049         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4050         WARN_ON(fs_info->trans_block_rsv.size > 0);
4051         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4052         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4053         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4054         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4055         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4056 }
4057
4058 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4059                                   struct btrfs_root *root)
4060 {
4061         if (!trans->bytes_reserved)
4062                 return;
4063
4064         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4065         trans->bytes_reserved = 0;
4066 }
4067
4068 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4069                                   struct inode *inode)
4070 {
4071         struct btrfs_root *root = BTRFS_I(inode)->root;
4072         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4073         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4074
4075         /*
4076          * We need to hold space in order to delete our orphan item once we've
4077          * added it, so this takes the reservation so we can release it later
4078          * when we are truly done with the orphan item.
4079          */
4080         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4081         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4082 }
4083
4084 void btrfs_orphan_release_metadata(struct inode *inode)
4085 {
4086         struct btrfs_root *root = BTRFS_I(inode)->root;
4087         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4088         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4089 }
4090
4091 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
4092                                 struct btrfs_pending_snapshot *pending)
4093 {
4094         struct btrfs_root *root = pending->root;
4095         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4096         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
4097         /*
4098          * two for root back/forward refs, two for directory entries
4099          * and one for root of the snapshot.
4100          */
4101         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
4102         dst_rsv->space_info = src_rsv->space_info;
4103         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4104 }
4105
4106 /**
4107  * drop_outstanding_extent - drop an outstanding extent
4108  * @inode: the inode we're dropping the extent for
4109  *
4110  * This is called when we are freeing up an outstanding extent, either called
4111  * after an error or after an extent is written.  This will return the number of
4112  * reserved extents that need to be freed.  This must be called with
4113  * BTRFS_I(inode)->lock held.
4114  */
4115 static unsigned drop_outstanding_extent(struct inode *inode)
4116 {
4117         unsigned drop_inode_space = 0;
4118         unsigned dropped_extents = 0;
4119
4120         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4121         BTRFS_I(inode)->outstanding_extents--;
4122
4123         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4124             BTRFS_I(inode)->delalloc_meta_reserved) {
4125                 drop_inode_space = 1;
4126                 BTRFS_I(inode)->delalloc_meta_reserved = 0;
4127         }
4128
4129         /*
4130          * If we have more or the same amount of outsanding extents than we have
4131          * reserved then we need to leave the reserved extents count alone.
4132          */
4133         if (BTRFS_I(inode)->outstanding_extents >=
4134             BTRFS_I(inode)->reserved_extents)
4135                 return drop_inode_space;
4136
4137         dropped_extents = BTRFS_I(inode)->reserved_extents -
4138                 BTRFS_I(inode)->outstanding_extents;
4139         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4140         return dropped_extents + drop_inode_space;
4141 }
4142
4143 /**
4144  * calc_csum_metadata_size - return the amount of metada space that must be
4145  *      reserved/free'd for the given bytes.
4146  * @inode: the inode we're manipulating
4147  * @num_bytes: the number of bytes in question
4148  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4149  *
4150  * This adjusts the number of csum_bytes in the inode and then returns the
4151  * correct amount of metadata that must either be reserved or freed.  We
4152  * calculate how many checksums we can fit into one leaf and then divide the
4153  * number of bytes that will need to be checksumed by this value to figure out
4154  * how many checksums will be required.  If we are adding bytes then the number
4155  * may go up and we will return the number of additional bytes that must be
4156  * reserved.  If it is going down we will return the number of bytes that must
4157  * be freed.
4158  *
4159  * This must be called with BTRFS_I(inode)->lock held.
4160  */
4161 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4162                                    int reserve)
4163 {
4164         struct btrfs_root *root = BTRFS_I(inode)->root;
4165         u64 csum_size;
4166         int num_csums_per_leaf;
4167         int num_csums;
4168         int old_csums;
4169
4170         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4171             BTRFS_I(inode)->csum_bytes == 0)
4172                 return 0;
4173
4174         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4175         if (reserve)
4176                 BTRFS_I(inode)->csum_bytes += num_bytes;
4177         else
4178                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4179         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4180         num_csums_per_leaf = (int)div64_u64(csum_size,
4181                                             sizeof(struct btrfs_csum_item) +
4182                                             sizeof(struct btrfs_disk_key));
4183         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4184         num_csums = num_csums + num_csums_per_leaf - 1;
4185         num_csums = num_csums / num_csums_per_leaf;
4186
4187         old_csums = old_csums + num_csums_per_leaf - 1;
4188         old_csums = old_csums / num_csums_per_leaf;
4189
4190         /* No change, no need to reserve more */
4191         if (old_csums == num_csums)
4192                 return 0;
4193
4194         if (reserve)
4195                 return btrfs_calc_trans_metadata_size(root,
4196                                                       num_csums - old_csums);
4197
4198         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4199 }
4200
4201 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4202 {
4203         struct btrfs_root *root = BTRFS_I(inode)->root;
4204         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4205         u64 to_reserve = 0;
4206         unsigned nr_extents = 0;
4207         int flush = 1;
4208         int ret;
4209
4210         if (btrfs_is_free_space_inode(root, inode))
4211                 flush = 0;
4212
4213         if (flush && btrfs_transaction_in_commit(root->fs_info))
4214                 schedule_timeout(1);
4215
4216         num_bytes = ALIGN(num_bytes, root->sectorsize);
4217
4218         spin_lock(&BTRFS_I(inode)->lock);
4219         BTRFS_I(inode)->outstanding_extents++;
4220
4221         if (BTRFS_I(inode)->outstanding_extents >
4222             BTRFS_I(inode)->reserved_extents) {
4223                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4224                         BTRFS_I(inode)->reserved_extents;
4225                 BTRFS_I(inode)->reserved_extents += nr_extents;
4226         }
4227
4228         /*
4229          * Add an item to reserve for updating the inode when we complete the
4230          * delalloc io.
4231          */
4232         if (!BTRFS_I(inode)->delalloc_meta_reserved) {
4233                 nr_extents++;
4234                 BTRFS_I(inode)->delalloc_meta_reserved = 1;
4235         }
4236
4237         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4238         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4239         spin_unlock(&BTRFS_I(inode)->lock);
4240
4241         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4242         if (ret) {
4243                 u64 to_free = 0;
4244                 unsigned dropped;
4245
4246                 spin_lock(&BTRFS_I(inode)->lock);
4247                 dropped = drop_outstanding_extent(inode);
4248                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4249                 spin_unlock(&BTRFS_I(inode)->lock);
4250                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4251
4252                 /*
4253                  * Somebody could have come in and twiddled with the
4254                  * reservation, so if we have to free more than we would have
4255                  * reserved from this reservation go ahead and release those
4256                  * bytes.
4257                  */
4258                 to_free -= to_reserve;
4259                 if (to_free)
4260                         btrfs_block_rsv_release(root, block_rsv, to_free);
4261                 return ret;
4262         }
4263
4264         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4265
4266         return 0;
4267 }
4268
4269 /**
4270  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
4271  * @inode: the inode to release the reservation for
4272  * @num_bytes: the number of bytes we're releasing
4273  *
4274  * This will release the metadata reservation for an inode.  This can be called
4275  * once we complete IO for a given set of bytes to release their metadata
4276  * reservations.
4277  */
4278 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4279 {
4280         struct btrfs_root *root = BTRFS_I(inode)->root;
4281         u64 to_free = 0;
4282         unsigned dropped;
4283
4284         num_bytes = ALIGN(num_bytes, root->sectorsize);
4285         spin_lock(&BTRFS_I(inode)->lock);
4286         dropped = drop_outstanding_extent(inode);
4287
4288         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4289         spin_unlock(&BTRFS_I(inode)->lock);
4290         if (dropped > 0)
4291                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4292
4293         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4294                                 to_free);
4295 }
4296
4297 /**
4298  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
4299  * @inode: inode we're writing to
4300  * @num_bytes: the number of bytes we want to allocate
4301  *
4302  * This will do the following things
4303  *
4304  * o reserve space in the data space info for num_bytes
4305  * o reserve space in the metadata space info based on number of outstanding
4306  *   extents and how much csums will be needed
4307  * o add to the inodes ->delalloc_bytes
4308  * o add it to the fs_info's delalloc inodes list.
4309  *
4310  * This will return 0 for success and -ENOSPC if there is no space left.
4311  */
4312 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4313 {
4314         int ret;
4315
4316         ret = btrfs_check_data_free_space(inode, num_bytes);
4317         if (ret)
4318                 return ret;
4319
4320         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4321         if (ret) {
4322                 btrfs_free_reserved_data_space(inode, num_bytes);
4323                 return ret;
4324         }
4325
4326         return 0;
4327 }
4328
4329 /**
4330  * btrfs_delalloc_release_space - release data and metadata space for delalloc
4331  * @inode: inode we're releasing space for
4332  * @num_bytes: the number of bytes we want to free up
4333  *
4334  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
4335  * called in the case that we don't need the metadata AND data reservations
4336  * anymore.  So if there is an error or we insert an inline extent.
4337  *
4338  * This function will release the metadata space that was not used and will
4339  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
4340  * list if there are no delalloc bytes left.
4341  */
4342 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4343 {
4344         btrfs_delalloc_release_metadata(inode, num_bytes);
4345         btrfs_free_reserved_data_space(inode, num_bytes);
4346 }
4347
4348 static int update_block_group(struct btrfs_trans_handle *trans,
4349                               struct btrfs_root *root,
4350                               u64 bytenr, u64 num_bytes, int alloc)
4351 {
4352         struct btrfs_block_group_cache *cache = NULL;
4353         struct btrfs_fs_info *info = root->fs_info;
4354         u64 total = num_bytes;
4355         u64 old_val;
4356         u64 byte_in_group;
4357         int factor;
4358
4359         /* block accounting for super block */
4360         spin_lock(&info->delalloc_lock);
4361         old_val = btrfs_super_bytes_used(info->super_copy);
4362         if (alloc)
4363                 old_val += num_bytes;
4364         else
4365                 old_val -= num_bytes;
4366         btrfs_set_super_bytes_used(info->super_copy, old_val);
4367         spin_unlock(&info->delalloc_lock);
4368
4369         while (total) {
4370                 cache = btrfs_lookup_block_group(info, bytenr);
4371                 if (!cache)
4372                         return -1;
4373                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4374                                     BTRFS_BLOCK_GROUP_RAID1 |
4375                                     BTRFS_BLOCK_GROUP_RAID10))
4376                         factor = 2;
4377                 else
4378                         factor = 1;
4379                 /*
4380                  * If this block group has free space cache written out, we
4381                  * need to make sure to load it if we are removing space.  This
4382                  * is because we need the unpinning stage to actually add the
4383                  * space back to the block group, otherwise we will leak space.
4384                  */
4385                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4386                         cache_block_group(cache, trans, NULL, 1);
4387
4388                 byte_in_group = bytenr - cache->key.objectid;
4389                 WARN_ON(byte_in_group > cache->key.offset);
4390
4391                 spin_lock(&cache->space_info->lock);
4392                 spin_lock(&cache->lock);
4393
4394                 if (btrfs_test_opt(root, SPACE_CACHE) &&
4395                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4396                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4397
4398                 cache->dirty = 1;
4399                 old_val = btrfs_block_group_used(&cache->item);
4400                 num_bytes = min(total, cache->key.offset - byte_in_group);
4401                 if (alloc) {
4402                         old_val += num_bytes;
4403                         btrfs_set_block_group_used(&cache->item, old_val);
4404                         cache->reserved -= num_bytes;
4405                         cache->space_info->bytes_reserved -= num_bytes;
4406                         cache->space_info->bytes_used += num_bytes;
4407                         cache->space_info->disk_used += num_bytes * factor;
4408                         spin_unlock(&cache->lock);
4409                         spin_unlock(&cache->space_info->lock);
4410                 } else {
4411                         old_val -= num_bytes;
4412                         btrfs_set_block_group_used(&cache->item, old_val);
4413                         cache->pinned += num_bytes;
4414                         cache->space_info->bytes_pinned += num_bytes;
4415                         cache->space_info->bytes_used -= num_bytes;
4416                         cache->space_info->disk_used -= num_bytes * factor;
4417                         spin_unlock(&cache->lock);
4418                         spin_unlock(&cache->space_info->lock);
4419
4420                         set_extent_dirty(info->pinned_extents,
4421                                          bytenr, bytenr + num_bytes - 1,
4422                                          GFP_NOFS | __GFP_NOFAIL);
4423                 }
4424                 btrfs_put_block_group(cache);
4425                 total -= num_bytes;
4426                 bytenr += num_bytes;
4427         }
4428         return 0;
4429 }
4430
4431 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4432 {
4433         struct btrfs_block_group_cache *cache;
4434         u64 bytenr;
4435
4436         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4437         if (!cache)
4438                 return 0;
4439
4440         bytenr = cache->key.objectid;
4441         btrfs_put_block_group(cache);
4442
4443         return bytenr;
4444 }
4445
4446 static int pin_down_extent(struct btrfs_root *root,
4447                            struct btrfs_block_group_cache *cache,
4448                            u64 bytenr, u64 num_bytes, int reserved)
4449 {
4450         spin_lock(&cache->space_info->lock);
4451         spin_lock(&cache->lock);
4452         cache->pinned += num_bytes;
4453         cache->space_info->bytes_pinned += num_bytes;
4454         if (reserved) {
4455                 cache->reserved -= num_bytes;
4456                 cache->space_info->bytes_reserved -= num_bytes;
4457         }
4458         spin_unlock(&cache->lock);
4459         spin_unlock(&cache->space_info->lock);
4460
4461         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4462                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4463         return 0;
4464 }
4465
4466 /*
4467  * this function must be called within transaction
4468  */
4469 int btrfs_pin_extent(struct btrfs_root *root,
4470                      u64 bytenr, u64 num_bytes, int reserved)
4471 {
4472         struct btrfs_block_group_cache *cache;
4473
4474         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4475         BUG_ON(!cache);
4476
4477         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4478
4479         btrfs_put_block_group(cache);
4480         return 0;
4481 }
4482
4483 /*
4484  * this function must be called within transaction
4485  */
4486 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
4487                                     struct btrfs_root *root,
4488                                     u64 bytenr, u64 num_bytes)
4489 {
4490         struct btrfs_block_group_cache *cache;
4491
4492         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4493         BUG_ON(!cache);
4494
4495         /*
4496          * pull in the free space cache (if any) so that our pin
4497          * removes the free space from the cache.  We have load_only set
4498          * to one because the slow code to read in the free extents does check
4499          * the pinned extents.
4500          */
4501         cache_block_group(cache, trans, root, 1);
4502
4503         pin_down_extent(root, cache, bytenr, num_bytes, 0);
4504
4505         /* remove us from the free space cache (if we're there at all) */
4506         btrfs_remove_free_space(cache, bytenr, num_bytes);
4507         btrfs_put_block_group(cache);
4508         return 0;
4509 }
4510
4511 /**
4512  * btrfs_update_reserved_bytes - update the block_group and space info counters
4513  * @cache:      The cache we are manipulating
4514  * @num_bytes:  The number of bytes in question
4515  * @reserve:    One of the reservation enums
4516  *
4517  * This is called by the allocator when it reserves space, or by somebody who is
4518  * freeing space that was never actually used on disk.  For example if you
4519  * reserve some space for a new leaf in transaction A and before transaction A
4520  * commits you free that leaf, you call this with reserve set to 0 in order to
4521  * clear the reservation.
4522  *
4523  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
4524  * ENOSPC accounting.  For data we handle the reservation through clearing the
4525  * delalloc bits in the io_tree.  We have to do this since we could end up
4526  * allocating less disk space for the amount of data we have reserved in the
4527  * case of compression.
4528  *
4529  * If this is a reservation and the block group has become read only we cannot
4530  * make the reservation and return -EAGAIN, otherwise this function always
4531  * succeeds.
4532  */
4533 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4534                                        u64 num_bytes, int reserve)
4535 {
4536         struct btrfs_space_info *space_info = cache->space_info;
4537         int ret = 0;
4538         spin_lock(&space_info->lock);
4539         spin_lock(&cache->lock);
4540         if (reserve != RESERVE_FREE) {
4541                 if (cache->ro) {
4542                         ret = -EAGAIN;
4543                 } else {
4544                         cache->reserved += num_bytes;
4545                         space_info->bytes_reserved += num_bytes;
4546                         if (reserve == RESERVE_ALLOC) {
4547                                 BUG_ON(space_info->bytes_may_use < num_bytes);
4548                                 space_info->bytes_may_use -= num_bytes;
4549                         }
4550                 }
4551         } else {
4552                 if (cache->ro)
4553                         space_info->bytes_readonly += num_bytes;
4554                 cache->reserved -= num_bytes;
4555                 space_info->bytes_reserved -= num_bytes;
4556                 space_info->reservation_progress++;
4557         }
4558         spin_unlock(&cache->lock);
4559         spin_unlock(&space_info->lock);
4560         return ret;
4561 }
4562
4563 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4564                                 struct btrfs_root *root)
4565 {
4566         struct btrfs_fs_info *fs_info = root->fs_info;
4567         struct btrfs_caching_control *next;
4568         struct btrfs_caching_control *caching_ctl;
4569         struct btrfs_block_group_cache *cache;
4570
4571         down_write(&fs_info->extent_commit_sem);
4572
4573         list_for_each_entry_safe(caching_ctl, next,
4574                                  &fs_info->caching_block_groups, list) {
4575                 cache = caching_ctl->block_group;
4576                 if (block_group_cache_done(cache)) {
4577                         cache->last_byte_to_unpin = (u64)-1;
4578                         list_del_init(&caching_ctl->list);
4579                         put_caching_control(caching_ctl);
4580                 } else {
4581                         cache->last_byte_to_unpin = caching_ctl->progress;
4582                 }
4583         }
4584
4585         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4586                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4587         else
4588                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4589
4590         up_write(&fs_info->extent_commit_sem);
4591
4592         update_global_block_rsv(fs_info);
4593         return 0;
4594 }
4595
4596 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4597 {
4598         struct btrfs_fs_info *fs_info = root->fs_info;
4599         struct btrfs_block_group_cache *cache = NULL;
4600         u64 len;
4601
4602         while (start <= end) {
4603                 if (!cache ||
4604                     start >= cache->key.objectid + cache->key.offset) {
4605                         if (cache)
4606                                 btrfs_put_block_group(cache);
4607                         cache = btrfs_lookup_block_group(fs_info, start);
4608                         BUG_ON(!cache);
4609                 }
4610
4611                 len = cache->key.objectid + cache->key.offset - start;
4612                 len = min(len, end + 1 - start);
4613
4614                 if (start < cache->last_byte_to_unpin) {
4615                         len = min(len, cache->last_byte_to_unpin - start);
4616                         btrfs_add_free_space(cache, start, len);
4617                 }
4618
4619                 start += len;
4620
4621                 spin_lock(&cache->space_info->lock);
4622                 spin_lock(&cache->lock);
4623                 cache->pinned -= len;
4624                 cache->space_info->bytes_pinned -= len;
4625                 if (cache->ro)
4626                         cache->space_info->bytes_readonly += len;
4627                 spin_unlock(&cache->lock);
4628                 spin_unlock(&cache->space_info->lock);
4629         }
4630
4631         if (cache)
4632                 btrfs_put_block_group(cache);
4633         return 0;
4634 }
4635
4636 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4637                                struct btrfs_root *root)
4638 {
4639         struct btrfs_fs_info *fs_info = root->fs_info;
4640         struct extent_io_tree *unpin;
4641         u64 start;
4642         u64 end;
4643         int ret;
4644
4645         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4646                 unpin = &fs_info->freed_extents[1];
4647         else
4648                 unpin = &fs_info->freed_extents[0];
4649
4650         while (1) {
4651                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4652                                             EXTENT_DIRTY);
4653                 if (ret)
4654                         break;
4655
4656                 if (btrfs_test_opt(root, DISCARD))
4657                         ret = btrfs_discard_extent(root, start,
4658                                                    end + 1 - start, NULL);
4659
4660                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4661                 unpin_extent_range(root, start, end);
4662                 cond_resched();
4663         }
4664
4665         return 0;
4666 }
4667
4668 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
4669                                 struct btrfs_root *root,
4670                                 u64 bytenr, u64 num_bytes, u64 parent,
4671                                 u64 root_objectid, u64 owner_objectid,
4672                                 u64 owner_offset, int refs_to_drop,
4673                                 struct btrfs_delayed_extent_op *extent_op)
4674 {
4675         struct btrfs_key key;
4676         struct btrfs_path *path;
4677         struct btrfs_fs_info *info = root->fs_info;
4678         struct btrfs_root *extent_root = info->extent_root;
4679         struct extent_buffer *leaf;
4680         struct btrfs_extent_item *ei;
4681         struct btrfs_extent_inline_ref *iref;
4682         int ret;
4683         int is_data;
4684         int extent_slot = 0;
4685         int found_extent = 0;
4686         int num_to_del = 1;
4687         u32 item_size;
4688         u64 refs;
4689
4690         path = btrfs_alloc_path();
4691         if (!path)
4692                 return -ENOMEM;
4693
4694         path->reada = 1;
4695         path->leave_spinning = 1;
4696
4697         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
4698         BUG_ON(!is_data && refs_to_drop != 1);
4699
4700         ret = lookup_extent_backref(trans, extent_root, path, &iref,
4701                                     bytenr, num_bytes, parent,
4702                                     root_objectid, owner_objectid,
4703                                     owner_offset);
4704         if (ret == 0) {
4705                 extent_slot = path->slots[0];
4706                 while (extent_slot >= 0) {
4707                         btrfs_item_key_to_cpu(path->nodes[0], &key,
4708                                               extent_slot);
4709                         if (key.objectid != bytenr)
4710                                 break;
4711                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
4712                             key.offset == num_bytes) {
4713                                 found_extent = 1;
4714                                 break;
4715                         }
4716                         if (path->slots[0] - extent_slot > 5)
4717                                 break;
4718                         extent_slot--;
4719                 }
4720 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4721                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
4722                 if (found_extent && item_size < sizeof(*ei))
4723                         found_extent = 0;
4724 #endif
4725                 if (!found_extent) {
4726                         BUG_ON(iref);
4727                         ret = remove_extent_backref(trans, extent_root, path,
4728                                                     NULL, refs_to_drop,
4729                                                     is_data);
4730                         BUG_ON(ret);
4731                         btrfs_release_path(path);
4732                         path->leave_spinning = 1;
4733
4734                         key.objectid = bytenr;
4735                         key.type = BTRFS_EXTENT_ITEM_KEY;
4736                         key.offset = num_bytes;
4737
4738                         ret = btrfs_search_slot(trans, extent_root,
4739                                                 &key, path, -1, 1);
4740                         if (ret) {
4741                                 printk(KERN_ERR "umm, got %d back from search"
4742                                        ", was looking for %llu\n", ret,
4743                                        (unsigned long long)bytenr);
4744                                 if (ret > 0)
4745                                         btrfs_print_leaf(extent_root,
4746                                                          path->nodes[0]);
4747                         }
4748                         BUG_ON(ret);
4749                         extent_slot = path->slots[0];
4750                 }
4751         } else {
4752                 btrfs_print_leaf(extent_root, path->nodes[0]);
4753                 WARN_ON(1);
4754                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
4755                        "parent %llu root %llu  owner %llu offset %llu\n",
4756                        (unsigned long long)bytenr,
4757                        (unsigned long long)parent,
4758                        (unsigned long long)root_objectid,
4759                        (unsigned long long)owner_objectid,
4760                        (unsigned long long)owner_offset);
4761         }
4762
4763         leaf = path->nodes[0];
4764         item_size = btrfs_item_size_nr(leaf, extent_slot);
4765 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4766         if (item_size < sizeof(*ei)) {
4767                 BUG_ON(found_extent || extent_slot != path->slots[0]);
4768                 ret = convert_extent_item_v0(trans, extent_root, path,
4769                                              owner_objectid, 0);
4770                 BUG_ON(ret < 0);
4771
4772                 btrfs_release_path(path);
4773                 path->leave_spinning = 1;
4774
4775                 key.objectid = bytenr;
4776                 key.type = BTRFS_EXTENT_ITEM_KEY;
4777                 key.offset = num_bytes;
4778
4779                 ret = btrfs_search_slot(trans, extent_root, &key, path,
4780                                         -1, 1);
4781                 if (ret) {
4782                         printk(KERN_ERR "umm, got %d back from search"
4783                                ", was looking for %llu\n", ret,
4784                                (unsigned long long)bytenr);
4785                         btrfs_print_leaf(extent_root, path->nodes[0]);
4786                 }
4787                 BUG_ON(ret);
4788                 extent_slot = path->slots[0];
4789                 leaf = path->nodes[0];
4790                 item_size = btrfs_item_size_nr(leaf, extent_slot);
4791         }
4792 #endif
4793         BUG_ON(item_size < sizeof(*ei));
4794         ei = btrfs_item_ptr(leaf, extent_slot,
4795                             struct btrfs_extent_item);
4796         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4797                 struct btrfs_tree_block_info *bi;
4798                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
4799                 bi = (struct btrfs_tree_block_info *)(ei + 1);
4800                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
4801         }
4802
4803         refs = btrfs_extent_refs(leaf, ei);
4804         BUG_ON(refs < refs_to_drop);
4805         refs -= refs_to_drop;
4806
4807         if (refs > 0) {
4808                 if (extent_op)
4809                         __run_delayed_extent_op(extent_op, leaf, ei);
4810                 /*
4811                  * In the case of inline back ref, reference count will
4812                  * be updated by remove_extent_backref
4813                  */
4814                 if (iref) {
4815                         BUG_ON(!found_extent);
4816                 } else {
4817                         btrfs_set_extent_refs(leaf, ei, refs);
4818                         btrfs_mark_buffer_dirty(leaf);
4819                 }
4820                 if (found_extent) {
4821                         ret = remove_extent_backref(trans, extent_root, path,
4822                                                     iref, refs_to_drop,
4823                                                     is_data);
4824                         BUG_ON(ret);
4825                 }
4826         } else {
4827                 if (found_extent) {
4828                         BUG_ON(is_data && refs_to_drop !=
4829                                extent_data_ref_count(root, path, iref));
4830                         if (iref) {
4831                                 BUG_ON(path->slots[0] != extent_slot);
4832                         } else {
4833                                 BUG_ON(path->slots[0] != extent_slot + 1);
4834                                 path->slots[0] = extent_slot;
4835                                 num_to_del = 2;
4836                         }
4837                 }
4838
4839                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
4840                                       num_to_del);
4841                 BUG_ON(ret);
4842                 btrfs_release_path(path);
4843
4844                 if (is_data) {
4845                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
4846                         BUG_ON(ret);
4847                 } else {
4848                         invalidate_mapping_pages(info->btree_inode->i_mapping,
4849                              bytenr >> PAGE_CACHE_SHIFT,
4850                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
4851                 }
4852
4853                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
4854                 BUG_ON(ret);
4855         }
4856         btrfs_free_path(path);
4857         return ret;
4858 }
4859
4860 /*
4861  * when we free an block, it is possible (and likely) that we free the last
4862  * delayed ref for that extent as well.  This searches the delayed ref tree for
4863  * a given extent, and if there are no other delayed refs to be processed, it
4864  * removes it from the tree.
4865  */
4866 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
4867                                       struct btrfs_root *root, u64 bytenr)
4868 {
4869         struct btrfs_delayed_ref_head *head;
4870         struct btrfs_delayed_ref_root *delayed_refs;
4871         struct btrfs_delayed_ref_node *ref;
4872         struct rb_node *node;
4873         int ret = 0;
4874
4875         delayed_refs = &trans->transaction->delayed_refs;
4876         spin_lock(&delayed_refs->lock);
4877         head = btrfs_find_delayed_ref_head(trans, bytenr);
4878         if (!head)
4879                 goto out;
4880
4881         node = rb_prev(&head->node.rb_node);
4882         if (!node)
4883                 goto out;
4884
4885         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
4886
4887         /* there are still entries for this ref, we can't drop it */
4888         if (ref->bytenr == bytenr)
4889                 goto out;
4890
4891         if (head->extent_op) {
4892                 if (!head->must_insert_reserved)
4893                         goto out;
4894                 kfree(head->extent_op);
4895                 head->extent_op = NULL;
4896         }
4897
4898         /*
4899          * waiting for the lock here would deadlock.  If someone else has it
4900          * locked they are already in the process of dropping it anyway
4901          */
4902         if (!mutex_trylock(&head->mutex))
4903                 goto out;
4904
4905         /*
4906          * at this point we have a head with no other entries.  Go
4907          * ahead and process it.
4908          */
4909         head->node.in_tree = 0;
4910         rb_erase(&head->node.rb_node, &delayed_refs->root);
4911
4912         delayed_refs->num_entries--;
4913
4914         /*
4915          * we don't take a ref on the node because we're removing it from the
4916          * tree, so we just steal the ref the tree was holding.
4917          */
4918         delayed_refs->num_heads--;
4919         if (list_empty(&head->cluster))
4920                 delayed_refs->num_heads_ready--;
4921
4922         list_del_init(&head->cluster);
4923         spin_unlock(&delayed_refs->lock);
4924
4925         BUG_ON(head->extent_op);
4926         if (head->must_insert_reserved)
4927                 ret = 1;
4928
4929         mutex_unlock(&head->mutex);
4930         btrfs_put_delayed_ref(&head->node);
4931         return ret;
4932 out:
4933         spin_unlock(&delayed_refs->lock);
4934         return 0;
4935 }
4936
4937 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
4938                            struct btrfs_root *root,
4939                            struct extent_buffer *buf,
4940                            u64 parent, int last_ref)
4941 {
4942         struct btrfs_block_group_cache *cache = NULL;
4943         int ret;
4944
4945         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4946                 ret = btrfs_add_delayed_tree_ref(trans, buf->start, buf->len,
4947                                                 parent, root->root_key.objectid,
4948                                                 btrfs_header_level(buf),
4949                                                 BTRFS_DROP_DELAYED_REF, NULL);
4950                 BUG_ON(ret);
4951         }
4952
4953         if (!last_ref)
4954                 return;
4955
4956         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
4957
4958         if (btrfs_header_generation(buf) == trans->transid) {
4959                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4960                         ret = check_ref_cleanup(trans, root, buf->start);
4961                         if (!ret)
4962                                 goto out;
4963                 }
4964
4965                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
4966                         pin_down_extent(root, cache, buf->start, buf->len, 1);
4967                         goto out;
4968                 }
4969
4970                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
4971
4972                 btrfs_add_free_space(cache, buf->start, buf->len);
4973                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
4974         }
4975 out:
4976         /*
4977          * Deleting the buffer, clear the corrupt flag since it doesn't matter
4978          * anymore.
4979          */
4980         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
4981         btrfs_put_block_group(cache);
4982 }
4983
4984 int btrfs_free_extent(struct btrfs_trans_handle *trans,
4985                       struct btrfs_root *root,
4986                       u64 bytenr, u64 num_bytes, u64 parent,
4987                       u64 root_objectid, u64 owner, u64 offset)
4988 {
4989         int ret;
4990
4991         /*
4992          * tree log blocks never actually go into the extent allocation
4993          * tree, just update pinning info and exit early.
4994          */
4995         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
4996                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
4997                 /* unlocks the pinned mutex */
4998                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
4999                 ret = 0;
5000         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5001                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
5002                                         parent, root_objectid, (int)owner,
5003                                         BTRFS_DROP_DELAYED_REF, NULL);
5004                 BUG_ON(ret);
5005         } else {
5006                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
5007                                         parent, root_objectid, owner,
5008                                         offset, BTRFS_DROP_DELAYED_REF, NULL);
5009                 BUG_ON(ret);
5010         }
5011         return ret;
5012 }
5013
5014 static u64 stripe_align(struct btrfs_root *root, u64 val)
5015 {
5016         u64 mask = ((u64)root->stripesize - 1);
5017         u64 ret = (val + mask) & ~mask;
5018         return ret;
5019 }
5020
5021 /*
5022  * when we wait for progress in the block group caching, its because
5023  * our allocation attempt failed at least once.  So, we must sleep
5024  * and let some progress happen before we try again.
5025  *
5026  * This function will sleep at least once waiting for new free space to
5027  * show up, and then it will check the block group free space numbers
5028  * for our min num_bytes.  Another option is to have it go ahead
5029  * and look in the rbtree for a free extent of a given size, but this
5030  * is a good start.
5031  */
5032 static noinline int
5033 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
5034                                 u64 num_bytes)
5035 {
5036         struct btrfs_caching_control *caching_ctl;
5037         DEFINE_WAIT(wait);
5038
5039         caching_ctl = get_caching_control(cache);
5040         if (!caching_ctl)
5041                 return 0;
5042
5043         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
5044                    (cache->free_space_ctl->free_space >= num_bytes));
5045
5046         put_caching_control(caching_ctl);
5047         return 0;
5048 }
5049
5050 static noinline int
5051 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
5052 {
5053         struct btrfs_caching_control *caching_ctl;
5054         DEFINE_WAIT(wait);
5055
5056         caching_ctl = get_caching_control(cache);
5057         if (!caching_ctl)
5058                 return 0;
5059
5060         wait_event(caching_ctl->wait, block_group_cache_done(cache));
5061
5062         put_caching_control(caching_ctl);
5063         return 0;
5064 }
5065
5066 static int get_block_group_index(struct btrfs_block_group_cache *cache)
5067 {
5068         int index;
5069         if (cache->flags & BTRFS_BLOCK_GROUP_RAID10)
5070                 index = 0;
5071         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID1)
5072                 index = 1;
5073         else if (cache->flags & BTRFS_BLOCK_GROUP_DUP)
5074                 index = 2;
5075         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID0)
5076                 index = 3;
5077         else
5078                 index = 4;
5079         return index;
5080 }
5081
5082 enum btrfs_loop_type {
5083         LOOP_FIND_IDEAL = 0,
5084         LOOP_CACHING_NOWAIT = 1,
5085         LOOP_CACHING_WAIT = 2,
5086         LOOP_ALLOC_CHUNK = 3,
5087         LOOP_NO_EMPTY_SIZE = 4,
5088 };
5089
5090 /*
5091  * walks the btree of allocated extents and find a hole of a given size.
5092  * The key ins is changed to record the hole:
5093  * ins->objectid == block start
5094  * ins->flags = BTRFS_EXTENT_ITEM_KEY
5095  * ins->offset == number of blocks
5096  * Any available blocks before search_start are skipped.
5097  */
5098 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
5099                                      struct btrfs_root *orig_root,
5100                                      u64 num_bytes, u64 empty_size,
5101                                      u64 search_start, u64 search_end,
5102                                      u64 hint_byte, struct btrfs_key *ins,
5103                                      u64 data)
5104 {
5105         int ret = 0;
5106         struct btrfs_root *root = orig_root->fs_info->extent_root;
5107         struct btrfs_free_cluster *last_ptr = NULL;
5108         struct btrfs_block_group_cache *block_group = NULL;
5109         int empty_cluster = 2 * 1024 * 1024;
5110         int allowed_chunk_alloc = 0;
5111         int done_chunk_alloc = 0;
5112         struct btrfs_space_info *space_info;
5113         int last_ptr_loop = 0;
5114         int loop = 0;
5115         int index = 0;
5116         int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ?
5117                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
5118         bool found_uncached_bg = false;
5119         bool failed_cluster_refill = false;
5120         bool failed_alloc = false;
5121         bool use_cluster = true;
5122         bool have_caching_bg = false;
5123         u64 ideal_cache_percent = 0;
5124         u64 ideal_cache_offset = 0;
5125
5126         WARN_ON(num_bytes < root->sectorsize);
5127         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
5128         ins->objectid = 0;
5129         ins->offset = 0;
5130
5131         space_info = __find_space_info(root->fs_info, data);
5132         if (!space_info) {
5133                 printk(KERN_ERR "No space info for %llu\n", data);
5134                 return -ENOSPC;
5135         }
5136
5137         /*
5138          * If the space info is for both data and metadata it means we have a
5139          * small filesystem and we can't use the clustering stuff.
5140          */
5141         if (btrfs_mixed_space_info(space_info))
5142                 use_cluster = false;
5143
5144         if (orig_root->ref_cows || empty_size)
5145                 allowed_chunk_alloc = 1;
5146
5147         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
5148                 last_ptr = &root->fs_info->meta_alloc_cluster;
5149                 if (!btrfs_test_opt(root, SSD))
5150                         empty_cluster = 64 * 1024;
5151         }
5152
5153         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
5154             btrfs_test_opt(root, SSD)) {
5155                 last_ptr = &root->fs_info->data_alloc_cluster;
5156         }
5157
5158         if (last_ptr) {
5159                 spin_lock(&last_ptr->lock);
5160                 if (last_ptr->block_group)
5161                         hint_byte = last_ptr->window_start;
5162                 spin_unlock(&last_ptr->lock);
5163         }
5164
5165         search_start = max(search_start, first_logical_byte(root, 0));
5166         search_start = max(search_start, hint_byte);
5167
5168         if (!last_ptr)
5169                 empty_cluster = 0;
5170
5171         if (search_start == hint_byte) {
5172 ideal_cache:
5173                 block_group = btrfs_lookup_block_group(root->fs_info,
5174                                                        search_start);
5175                 /*
5176                  * we don't want to use the block group if it doesn't match our
5177                  * allocation bits, or if its not cached.
5178                  *
5179                  * However if we are re-searching with an ideal block group
5180                  * picked out then we don't care that the block group is cached.
5181                  */
5182                 if (block_group && block_group_bits(block_group, data) &&
5183                     (block_group->cached != BTRFS_CACHE_NO ||
5184                      search_start == ideal_cache_offset)) {
5185                         down_read(&space_info->groups_sem);
5186                         if (list_empty(&block_group->list) ||
5187                             block_group->ro) {
5188                                 /*
5189                                  * someone is removing this block group,
5190                                  * we can't jump into the have_block_group
5191                                  * target because our list pointers are not
5192                                  * valid
5193                                  */
5194                                 btrfs_put_block_group(block_group);
5195                                 up_read(&space_info->groups_sem);
5196                         } else {
5197                                 index = get_block_group_index(block_group);
5198                                 goto have_block_group;
5199                         }
5200                 } else if (block_group) {
5201                         btrfs_put_block_group(block_group);
5202                 }
5203         }
5204 search:
5205         have_caching_bg = false;
5206         down_read(&space_info->groups_sem);
5207         list_for_each_entry(block_group, &space_info->block_groups[index],
5208                             list) {
5209                 u64 offset;
5210                 int cached;
5211
5212                 btrfs_get_block_group(block_group);
5213                 search_start = block_group->key.objectid;
5214
5215                 /*
5216                  * this can happen if we end up cycling through all the
5217                  * raid types, but we want to make sure we only allocate
5218                  * for the proper type.
5219                  */
5220                 if (!block_group_bits(block_group, data)) {
5221                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
5222                                 BTRFS_BLOCK_GROUP_RAID1 |
5223                                 BTRFS_BLOCK_GROUP_RAID10;
5224
5225                         /*
5226                          * if they asked for extra copies and this block group
5227                          * doesn't provide them, bail.  This does allow us to
5228                          * fill raid0 from raid1.
5229                          */
5230                         if ((data & extra) && !(block_group->flags & extra))
5231                                 goto loop;
5232                 }
5233
5234 have_block_group:
5235                 cached = block_group_cache_done(block_group);
5236                 if (unlikely(!cached)) {
5237                         u64 free_percent;
5238
5239                         found_uncached_bg = true;
5240                         ret = cache_block_group(block_group, trans,
5241                                                 orig_root, 1);
5242                         if (block_group->cached == BTRFS_CACHE_FINISHED)
5243                                 goto alloc;
5244
5245                         free_percent = btrfs_block_group_used(&block_group->item);
5246                         free_percent *= 100;
5247                         free_percent = div64_u64(free_percent,
5248                                                  block_group->key.offset);
5249                         free_percent = 100 - free_percent;
5250                         if (free_percent > ideal_cache_percent &&
5251                             likely(!block_group->ro)) {
5252                                 ideal_cache_offset = block_group->key.objectid;
5253                                 ideal_cache_percent = free_percent;
5254                         }
5255
5256                         /*
5257                          * The caching workers are limited to 2 threads, so we
5258                          * can queue as much work as we care to.
5259                          */
5260                         if (loop > LOOP_FIND_IDEAL) {
5261                                 ret = cache_block_group(block_group, trans,
5262                                                         orig_root, 0);
5263                                 BUG_ON(ret);
5264                         }
5265
5266                         /*
5267                          * If loop is set for cached only, try the next block
5268                          * group.
5269                          */
5270                         if (loop == LOOP_FIND_IDEAL)
5271                                 goto loop;
5272                 }
5273
5274 alloc:
5275                 if (unlikely(block_group->ro))
5276                         goto loop;
5277
5278                 spin_lock(&block_group->free_space_ctl->tree_lock);
5279                 if (cached &&
5280                     block_group->free_space_ctl->free_space <
5281                     num_bytes + empty_cluster + empty_size) {
5282                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5283                         goto loop;
5284                 }
5285                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5286
5287                 /*
5288                  * Ok we want to try and use the cluster allocator, so
5289                  * lets look there
5290                  */
5291                 if (last_ptr) {
5292                         /*
5293                          * the refill lock keeps out other
5294                          * people trying to start a new cluster
5295                          */
5296                         spin_lock(&last_ptr->refill_lock);
5297                         if (!last_ptr->block_group ||
5298                             last_ptr->block_group->ro ||
5299                             !block_group_bits(last_ptr->block_group, data))
5300                                 goto refill_cluster;
5301
5302                         offset = btrfs_alloc_from_cluster(block_group, last_ptr,
5303                                                  num_bytes, search_start);
5304                         if (offset) {
5305                                 /* we have a block, we're done */
5306                                 spin_unlock(&last_ptr->refill_lock);
5307                                 goto checks;
5308                         }
5309
5310                         spin_lock(&last_ptr->lock);
5311                         /*
5312                          * whoops, this cluster doesn't actually point to
5313                          * this block group.  Get a ref on the block
5314                          * group is does point to and try again
5315                          */
5316                         if (!last_ptr_loop && last_ptr->block_group &&
5317                             last_ptr->block_group != block_group &&
5318                             index <=
5319                                  get_block_group_index(last_ptr->block_group)) {
5320
5321                                 btrfs_put_block_group(block_group);
5322                                 block_group = last_ptr->block_group;
5323                                 btrfs_get_block_group(block_group);
5324                                 spin_unlock(&last_ptr->lock);
5325                                 spin_unlock(&last_ptr->refill_lock);
5326
5327                                 last_ptr_loop = 1;
5328                                 search_start = block_group->key.objectid;
5329                                 /*
5330                                  * we know this block group is properly
5331                                  * in the list because
5332                                  * btrfs_remove_block_group, drops the
5333                                  * cluster before it removes the block
5334                                  * group from the list
5335                                  */
5336                                 goto have_block_group;
5337                         }
5338                         spin_unlock(&last_ptr->lock);
5339 refill_cluster:
5340                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
5341                          * set up a new clusters, so lets just skip it
5342                          * and let the allocator find whatever block
5343                          * it can find.  If we reach this point, we
5344                          * will have tried the cluster allocator
5345                          * plenty of times and not have found
5346                          * anything, so we are likely way too
5347                          * fragmented for the clustering stuff to find
5348                          * anything.  */
5349                         if (loop >= LOOP_NO_EMPTY_SIZE) {
5350                                 spin_unlock(&last_ptr->refill_lock);
5351                                 goto unclustered_alloc;
5352                         }
5353
5354                         /*
5355                          * this cluster didn't work out, free it and
5356                          * start over
5357                          */
5358                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5359
5360                         last_ptr_loop = 0;
5361
5362                         /* allocate a cluster in this block group */
5363                         ret = btrfs_find_space_cluster(trans, root,
5364                                                block_group, last_ptr,
5365                                                search_start, num_bytes,
5366                                                empty_cluster + empty_size);
5367                         if (ret == 0) {
5368                                 /*
5369                                  * now pull our allocation out of this
5370                                  * cluster
5371                                  */
5372                                 offset = btrfs_alloc_from_cluster(block_group,
5373                                                   last_ptr, num_bytes,
5374                                                   search_start);
5375                                 if (offset) {
5376                                         /* we found one, proceed */
5377                                         spin_unlock(&last_ptr->refill_lock);
5378                                         goto checks;
5379                                 }
5380                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5381                                    && !failed_cluster_refill) {
5382                                 spin_unlock(&last_ptr->refill_lock);
5383
5384                                 failed_cluster_refill = true;
5385                                 wait_block_group_cache_progress(block_group,
5386                                        num_bytes + empty_cluster + empty_size);
5387                                 goto have_block_group;
5388                         }
5389
5390                         /*
5391                          * at this point we either didn't find a cluster
5392                          * or we weren't able to allocate a block from our
5393                          * cluster.  Free the cluster we've been trying
5394                          * to use, and go to the next block group
5395                          */
5396                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5397                         spin_unlock(&last_ptr->refill_lock);
5398                         goto loop;
5399                 }
5400
5401 unclustered_alloc:
5402                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5403                                                     num_bytes, empty_size);
5404                 /*
5405                  * If we didn't find a chunk, and we haven't failed on this
5406                  * block group before, and this block group is in the middle of
5407                  * caching and we are ok with waiting, then go ahead and wait
5408                  * for progress to be made, and set failed_alloc to true.
5409                  *
5410                  * If failed_alloc is true then we've already waited on this
5411                  * block group once and should move on to the next block group.
5412                  */
5413                 if (!offset && !failed_alloc && !cached &&
5414                     loop > LOOP_CACHING_NOWAIT) {
5415                         wait_block_group_cache_progress(block_group,
5416                                                 num_bytes + empty_size);
5417                         failed_alloc = true;
5418                         goto have_block_group;
5419                 } else if (!offset) {
5420                         if (!cached)
5421                                 have_caching_bg = true;
5422                         goto loop;
5423                 }
5424 checks:
5425                 search_start = stripe_align(root, offset);
5426                 /* move on to the next group */
5427                 if (search_start + num_bytes >= search_end) {
5428                         btrfs_add_free_space(block_group, offset, num_bytes);
5429                         goto loop;
5430                 }
5431
5432                 /* move on to the next group */
5433                 if (search_start + num_bytes >
5434                     block_group->key.objectid + block_group->key.offset) {
5435                         btrfs_add_free_space(block_group, offset, num_bytes);
5436                         goto loop;
5437                 }
5438
5439                 ins->objectid = search_start;
5440                 ins->offset = num_bytes;
5441
5442                 if (offset < search_start)
5443                         btrfs_add_free_space(block_group, offset,
5444                                              search_start - offset);
5445                 BUG_ON(offset > search_start);
5446
5447                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
5448                                                   alloc_type);
5449                 if (ret == -EAGAIN) {
5450                         btrfs_add_free_space(block_group, offset, num_bytes);
5451                         goto loop;
5452                 }
5453
5454                 /* we are all good, lets return */
5455                 ins->objectid = search_start;
5456                 ins->offset = num_bytes;
5457
5458                 if (offset < search_start)
5459                         btrfs_add_free_space(block_group, offset,
5460                                              search_start - offset);
5461                 BUG_ON(offset > search_start);
5462                 btrfs_put_block_group(block_group);
5463                 break;
5464 loop:
5465                 failed_cluster_refill = false;
5466                 failed_alloc = false;
5467                 BUG_ON(index != get_block_group_index(block_group));
5468                 btrfs_put_block_group(block_group);
5469         }
5470         up_read(&space_info->groups_sem);
5471
5472         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
5473                 goto search;
5474
5475         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5476                 goto search;
5477
5478         /* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
5479          *                      for them to make caching progress.  Also
5480          *                      determine the best possible bg to cache
5481          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5482          *                      caching kthreads as we move along
5483          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5484          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5485          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5486          *                      again
5487          */
5488         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5489                 index = 0;
5490                 if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
5491                         found_uncached_bg = false;
5492                         loop++;
5493                         if (!ideal_cache_percent)
5494                                 goto search;
5495
5496                         /*
5497                          * 1 of the following 2 things have happened so far
5498                          *
5499                          * 1) We found an ideal block group for caching that
5500                          * is mostly full and will cache quickly, so we might
5501                          * as well wait for it.
5502                          *
5503                          * 2) We searched for cached only and we didn't find
5504                          * anything, and we didn't start any caching kthreads
5505                          * either, so chances are we will loop through and
5506                          * start a couple caching kthreads, and then come back
5507                          * around and just wait for them.  This will be slower
5508                          * because we will have 2 caching kthreads reading at
5509                          * the same time when we could have just started one
5510                          * and waited for it to get far enough to give us an
5511                          * allocation, so go ahead and go to the wait caching
5512                          * loop.
5513                          */
5514                         loop = LOOP_CACHING_WAIT;
5515                         search_start = ideal_cache_offset;
5516                         ideal_cache_percent = 0;
5517                         goto ideal_cache;
5518                 } else if (loop == LOOP_FIND_IDEAL) {
5519                         /*
5520                          * Didn't find a uncached bg, wait on anything we find
5521                          * next.
5522                          */
5523                         loop = LOOP_CACHING_WAIT;
5524                         goto search;
5525                 }
5526
5527                 loop++;
5528
5529                 if (loop == LOOP_ALLOC_CHUNK) {
5530                        if (allowed_chunk_alloc) {
5531                                 ret = do_chunk_alloc(trans, root, num_bytes +
5532                                                      2 * 1024 * 1024, data,
5533                                                      CHUNK_ALLOC_LIMITED);
5534                                 allowed_chunk_alloc = 0;
5535                                 if (ret == 1)
5536                                         done_chunk_alloc = 1;
5537                         } else if (!done_chunk_alloc &&
5538                                    space_info->force_alloc ==
5539                                    CHUNK_ALLOC_NO_FORCE) {
5540                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5541                         }
5542
5543                        /*
5544                         * We didn't allocate a chunk, go ahead and drop the
5545                         * empty size and loop again.
5546                         */
5547                        if (!done_chunk_alloc)
5548                                loop = LOOP_NO_EMPTY_SIZE;
5549                 }
5550
5551                 if (loop == LOOP_NO_EMPTY_SIZE) {
5552                         empty_size = 0;
5553                         empty_cluster = 0;
5554                 }
5555
5556                 goto search;
5557         } else if (!ins->objectid) {
5558                 ret = -ENOSPC;
5559         } else if (ins->objectid) {
5560                 ret = 0;
5561         }
5562
5563         return ret;
5564 }
5565
5566 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5567                             int dump_block_groups)
5568 {
5569         struct btrfs_block_group_cache *cache;
5570         int index = 0;
5571
5572         spin_lock(&info->lock);
5573         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
5574                (unsigned long long)info->flags,
5575                (unsigned long long)(info->total_bytes - info->bytes_used -
5576                                     info->bytes_pinned - info->bytes_reserved -
5577                                     info->bytes_readonly),
5578                (info->full) ? "" : "not ");
5579         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5580                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5581                (unsigned long long)info->total_bytes,
5582                (unsigned long long)info->bytes_used,
5583                (unsigned long long)info->bytes_pinned,
5584                (unsigned long long)info->bytes_reserved,
5585                (unsigned long long)info->bytes_may_use,
5586                (unsigned long long)info->bytes_readonly);
5587         spin_unlock(&info->lock);
5588
5589         if (!dump_block_groups)
5590                 return;
5591
5592         down_read(&info->groups_sem);
5593 again:
5594         list_for_each_entry(cache, &info->block_groups[index], list) {
5595                 spin_lock(&cache->lock);
5596                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
5597                        "%llu pinned %llu reserved\n",
5598                        (unsigned long long)cache->key.objectid,
5599                        (unsigned long long)cache->key.offset,
5600                        (unsigned long long)btrfs_block_group_used(&cache->item),
5601                        (unsigned long long)cache->pinned,
5602                        (unsigned long long)cache->reserved);
5603                 btrfs_dump_free_space(cache, bytes);
5604                 spin_unlock(&cache->lock);
5605         }
5606         if (++index < BTRFS_NR_RAID_TYPES)
5607                 goto again;
5608         up_read(&info->groups_sem);
5609 }
5610
5611 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5612                          struct btrfs_root *root,
5613                          u64 num_bytes, u64 min_alloc_size,
5614                          u64 empty_size, u64 hint_byte,
5615                          u64 search_end, struct btrfs_key *ins,
5616                          u64 data)
5617 {
5618         int ret;
5619         u64 search_start = 0;
5620
5621         data = btrfs_get_alloc_profile(root, data);
5622 again:
5623         /*
5624          * the only place that sets empty_size is btrfs_realloc_node, which
5625          * is not called recursively on allocations
5626          */
5627         if (empty_size || root->ref_cows)
5628                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5629                                      num_bytes + 2 * 1024 * 1024, data,
5630                                      CHUNK_ALLOC_NO_FORCE);
5631
5632         WARN_ON(num_bytes < root->sectorsize);
5633         ret = find_free_extent(trans, root, num_bytes, empty_size,
5634                                search_start, search_end, hint_byte,
5635                                ins, data);
5636
5637         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
5638                 num_bytes = num_bytes >> 1;
5639                 num_bytes = num_bytes & ~(root->sectorsize - 1);
5640                 num_bytes = max(num_bytes, min_alloc_size);
5641                 do_chunk_alloc(trans, root->fs_info->extent_root,
5642                                num_bytes, data, CHUNK_ALLOC_FORCE);
5643                 goto again;
5644         }
5645         if (ret == -ENOSPC && btrfs_test_opt(root, ENOSPC_DEBUG)) {
5646                 struct btrfs_space_info *sinfo;
5647
5648                 sinfo = __find_space_info(root->fs_info, data);
5649                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
5650                        "wanted %llu\n", (unsigned long long)data,
5651                        (unsigned long long)num_bytes);
5652                 dump_space_info(sinfo, num_bytes, 1);
5653         }
5654
5655         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5656
5657         return ret;
5658 }
5659
5660 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
5661                                         u64 start, u64 len, int pin)
5662 {
5663         struct btrfs_block_group_cache *cache;
5664         int ret = 0;
5665
5666         cache = btrfs_lookup_block_group(root->fs_info, start);
5667         if (!cache) {
5668                 printk(KERN_ERR "Unable to find block group for %llu\n",
5669                        (unsigned long long)start);
5670                 return -ENOSPC;
5671         }
5672
5673         if (btrfs_test_opt(root, DISCARD))
5674                 ret = btrfs_discard_extent(root, start, len, NULL);
5675
5676         if (pin)
5677                 pin_down_extent(root, cache, start, len, 1);
5678         else {
5679                 btrfs_add_free_space(cache, start, len);
5680                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
5681         }
5682         btrfs_put_block_group(cache);
5683
5684         trace_btrfs_reserved_extent_free(root, start, len);
5685
5686         return ret;
5687 }
5688
5689 int btrfs_free_reserved_extent(struct btrfs_root *root,
5690                                         u64 start, u64 len)
5691 {
5692         return __btrfs_free_reserved_extent(root, start, len, 0);
5693 }
5694
5695 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
5696                                        u64 start, u64 len)
5697 {
5698         return __btrfs_free_reserved_extent(root, start, len, 1);
5699 }
5700
5701 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5702                                       struct btrfs_root *root,
5703                                       u64 parent, u64 root_objectid,
5704                                       u64 flags, u64 owner, u64 offset,
5705                                       struct btrfs_key *ins, int ref_mod)
5706 {
5707         int ret;
5708         struct btrfs_fs_info *fs_info = root->fs_info;
5709         struct btrfs_extent_item *extent_item;
5710         struct btrfs_extent_inline_ref *iref;
5711         struct btrfs_path *path;
5712         struct extent_buffer *leaf;
5713         int type;
5714         u32 size;
5715
5716         if (parent > 0)
5717                 type = BTRFS_SHARED_DATA_REF_KEY;
5718         else
5719                 type = BTRFS_EXTENT_DATA_REF_KEY;
5720
5721         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
5722
5723         path = btrfs_alloc_path();
5724         if (!path)
5725                 return -ENOMEM;
5726
5727         path->leave_spinning = 1;
5728         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5729                                       ins, size);
5730         BUG_ON(ret);
5731
5732         leaf = path->nodes[0];
5733         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5734                                      struct btrfs_extent_item);
5735         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
5736         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5737         btrfs_set_extent_flags(leaf, extent_item,
5738                                flags | BTRFS_EXTENT_FLAG_DATA);
5739
5740         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
5741         btrfs_set_extent_inline_ref_type(leaf, iref, type);
5742         if (parent > 0) {
5743                 struct btrfs_shared_data_ref *ref;
5744                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
5745                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5746                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
5747         } else {
5748                 struct btrfs_extent_data_ref *ref;
5749                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
5750                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
5751                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
5752                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
5753                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
5754         }
5755
5756         btrfs_mark_buffer_dirty(path->nodes[0]);
5757         btrfs_free_path(path);
5758
5759         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5760         if (ret) {
5761                 printk(KERN_ERR "btrfs update block group failed for %llu "
5762                        "%llu\n", (unsigned long long)ins->objectid,
5763                        (unsigned long long)ins->offset);
5764                 BUG();
5765         }
5766         return ret;
5767 }
5768
5769 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
5770                                      struct btrfs_root *root,
5771                                      u64 parent, u64 root_objectid,
5772                                      u64 flags, struct btrfs_disk_key *key,
5773                                      int level, struct btrfs_key *ins)
5774 {
5775         int ret;
5776         struct btrfs_fs_info *fs_info = root->fs_info;
5777         struct btrfs_extent_item *extent_item;
5778         struct btrfs_tree_block_info *block_info;
5779         struct btrfs_extent_inline_ref *iref;
5780         struct btrfs_path *path;
5781         struct extent_buffer *leaf;
5782         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
5783
5784         path = btrfs_alloc_path();
5785         if (!path)
5786                 return -ENOMEM;
5787
5788         path->leave_spinning = 1;
5789         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5790                                       ins, size);
5791         BUG_ON(ret);
5792
5793         leaf = path->nodes[0];
5794         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5795                                      struct btrfs_extent_item);
5796         btrfs_set_extent_refs(leaf, extent_item, 1);
5797         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5798         btrfs_set_extent_flags(leaf, extent_item,
5799                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
5800         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
5801
5802         btrfs_set_tree_block_key(leaf, block_info, key);
5803         btrfs_set_tree_block_level(leaf, block_info, level);
5804
5805         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
5806         if (parent > 0) {
5807                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
5808                 btrfs_set_extent_inline_ref_type(leaf, iref,
5809                                                  BTRFS_SHARED_BLOCK_REF_KEY);
5810                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5811         } else {
5812                 btrfs_set_extent_inline_ref_type(leaf, iref,
5813                                                  BTRFS_TREE_BLOCK_REF_KEY);
5814                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
5815         }
5816
5817         btrfs_mark_buffer_dirty(leaf);
5818         btrfs_free_path(path);
5819
5820         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5821         if (ret) {
5822                 printk(KERN_ERR "btrfs update block group failed for %llu "
5823                        "%llu\n", (unsigned long long)ins->objectid,
5824                        (unsigned long long)ins->offset);
5825                 BUG();
5826         }
5827         return ret;
5828 }
5829
5830 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5831                                      struct btrfs_root *root,
5832                                      u64 root_objectid, u64 owner,
5833                                      u64 offset, struct btrfs_key *ins)
5834 {
5835         int ret;
5836
5837         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
5838
5839         ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
5840                                          0, root_objectid, owner, offset,
5841                                          BTRFS_ADD_DELAYED_EXTENT, NULL);
5842         return ret;
5843 }
5844
5845 /*
5846  * this is used by the tree logging recovery code.  It records that
5847  * an extent has been allocated and makes sure to clear the free
5848  * space cache bits as well
5849  */
5850 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
5851                                    struct btrfs_root *root,
5852                                    u64 root_objectid, u64 owner, u64 offset,
5853                                    struct btrfs_key *ins)
5854 {
5855         int ret;
5856         struct btrfs_block_group_cache *block_group;
5857         struct btrfs_caching_control *caching_ctl;
5858         u64 start = ins->objectid;
5859         u64 num_bytes = ins->offset;
5860
5861         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
5862         cache_block_group(block_group, trans, NULL, 0);
5863         caching_ctl = get_caching_control(block_group);
5864
5865         if (!caching_ctl) {
5866                 BUG_ON(!block_group_cache_done(block_group));
5867                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5868                 BUG_ON(ret);
5869         } else {
5870                 mutex_lock(&caching_ctl->mutex);
5871
5872                 if (start >= caching_ctl->progress) {
5873                         ret = add_excluded_extent(root, start, num_bytes);
5874                         BUG_ON(ret);
5875                 } else if (start + num_bytes <= caching_ctl->progress) {
5876                         ret = btrfs_remove_free_space(block_group,
5877                                                       start, num_bytes);
5878                         BUG_ON(ret);
5879                 } else {
5880                         num_bytes = caching_ctl->progress - start;
5881                         ret = btrfs_remove_free_space(block_group,
5882                                                       start, num_bytes);
5883                         BUG_ON(ret);
5884
5885                         start = caching_ctl->progress;
5886                         num_bytes = ins->objectid + ins->offset -
5887                                     caching_ctl->progress;
5888                         ret = add_excluded_extent(root, start, num_bytes);
5889                         BUG_ON(ret);
5890                 }
5891
5892                 mutex_unlock(&caching_ctl->mutex);
5893                 put_caching_control(caching_ctl);
5894         }
5895
5896         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
5897                                           RESERVE_ALLOC_NO_ACCOUNT);
5898         BUG_ON(ret);
5899         btrfs_put_block_group(block_group);
5900         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
5901                                          0, owner, offset, ins, 1);
5902         return ret;
5903 }
5904
5905 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
5906                                             struct btrfs_root *root,
5907                                             u64 bytenr, u32 blocksize,
5908                                             int level)
5909 {
5910         struct extent_buffer *buf;
5911
5912         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
5913         if (!buf)
5914                 return ERR_PTR(-ENOMEM);
5915         btrfs_set_header_generation(buf, trans->transid);
5916         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
5917         btrfs_tree_lock(buf);
5918         clean_tree_block(trans, root, buf);
5919
5920         btrfs_set_lock_blocking(buf);
5921         btrfs_set_buffer_uptodate(buf);
5922
5923         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
5924                 /*
5925                  * we allow two log transactions at a time, use different
5926                  * EXENT bit to differentiate dirty pages.
5927                  */
5928                 if (root->log_transid % 2 == 0)
5929                         set_extent_dirty(&root->dirty_log_pages, buf->start,
5930                                         buf->start + buf->len - 1, GFP_NOFS);
5931                 else
5932                         set_extent_new(&root->dirty_log_pages, buf->start,
5933                                         buf->start + buf->len - 1, GFP_NOFS);
5934         } else {
5935                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
5936                          buf->start + buf->len - 1, GFP_NOFS);
5937         }
5938         trans->blocks_used++;
5939         /* this returns a buffer locked for blocking */
5940         return buf;
5941 }
5942
5943 static struct btrfs_block_rsv *
5944 use_block_rsv(struct btrfs_trans_handle *trans,
5945               struct btrfs_root *root, u32 blocksize)
5946 {
5947         struct btrfs_block_rsv *block_rsv;
5948         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5949         int ret;
5950
5951         block_rsv = get_block_rsv(trans, root);
5952
5953         if (block_rsv->size == 0) {
5954                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
5955                 /*
5956                  * If we couldn't reserve metadata bytes try and use some from
5957                  * the global reserve.
5958                  */
5959                 if (ret && block_rsv != global_rsv) {
5960                         ret = block_rsv_use_bytes(global_rsv, blocksize);
5961                         if (!ret)
5962                                 return global_rsv;
5963                         return ERR_PTR(ret);
5964                 } else if (ret) {
5965                         return ERR_PTR(ret);
5966                 }
5967                 return block_rsv;
5968         }
5969
5970         ret = block_rsv_use_bytes(block_rsv, blocksize);
5971         if (!ret)
5972                 return block_rsv;
5973         if (ret) {
5974                 static DEFINE_RATELIMIT_STATE(_rs,
5975                                 DEFAULT_RATELIMIT_INTERVAL,
5976                                 /*DEFAULT_RATELIMIT_BURST*/ 2);
5977                 if (__ratelimit(&_rs)) {
5978                         printk(KERN_DEBUG "btrfs: block rsv returned %d\n", ret);
5979                         WARN_ON(1);
5980                 }
5981                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
5982                 if (!ret) {
5983                         return block_rsv;
5984                 } else if (ret && block_rsv != global_rsv) {
5985                         ret = block_rsv_use_bytes(global_rsv, blocksize);
5986                         if (!ret)
5987                                 return global_rsv;
5988                 }
5989         }
5990
5991         return ERR_PTR(-ENOSPC);
5992 }
5993
5994 static void unuse_block_rsv(struct btrfs_block_rsv *block_rsv, u32 blocksize)
5995 {
5996         block_rsv_add_bytes(block_rsv, blocksize, 0);
5997         block_rsv_release_bytes(block_rsv, NULL, 0);
5998 }
5999
6000 /*
6001  * finds a free extent and does all the dirty work required for allocation
6002  * returns the key for the extent through ins, and a tree buffer for
6003  * the first block of the extent through buf.
6004  *
6005  * returns the tree buffer or NULL.
6006  */
6007 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6008                                         struct btrfs_root *root, u32 blocksize,
6009                                         u64 parent, u64 root_objectid,
6010                                         struct btrfs_disk_key *key, int level,
6011                                         u64 hint, u64 empty_size)
6012 {
6013         struct btrfs_key ins;
6014         struct btrfs_block_rsv *block_rsv;
6015         struct extent_buffer *buf;
6016         u64 flags = 0;
6017         int ret;
6018
6019
6020         block_rsv = use_block_rsv(trans, root, blocksize);
6021         if (IS_ERR(block_rsv))
6022                 return ERR_CAST(block_rsv);
6023
6024         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6025                                    empty_size, hint, (u64)-1, &ins, 0);
6026         if (ret) {
6027                 unuse_block_rsv(block_rsv, blocksize);
6028                 return ERR_PTR(ret);
6029         }
6030
6031         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6032                                     blocksize, level);
6033         BUG_ON(IS_ERR(buf));
6034
6035         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6036                 if (parent == 0)
6037                         parent = ins.objectid;
6038                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6039         } else
6040                 BUG_ON(parent > 0);
6041
6042         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6043                 struct btrfs_delayed_extent_op *extent_op;
6044                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
6045                 BUG_ON(!extent_op);
6046                 if (key)
6047                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6048                 else
6049                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6050                 extent_op->flags_to_set = flags;
6051                 extent_op->update_key = 1;
6052                 extent_op->update_flags = 1;
6053                 extent_op->is_data = 0;
6054
6055                 ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
6056                                         ins.offset, parent, root_objectid,
6057                                         level, BTRFS_ADD_DELAYED_EXTENT,
6058                                         extent_op);
6059                 BUG_ON(ret);
6060         }
6061         return buf;
6062 }
6063
6064 struct walk_control {
6065         u64 refs[BTRFS_MAX_LEVEL];
6066         u64 flags[BTRFS_MAX_LEVEL];
6067         struct btrfs_key update_progress;
6068         int stage;
6069         int level;
6070         int shared_level;
6071         int update_ref;
6072         int keep_locks;
6073         int reada_slot;
6074         int reada_count;
6075 };
6076
6077 #define DROP_REFERENCE  1
6078 #define UPDATE_BACKREF  2
6079
6080 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6081                                      struct btrfs_root *root,
6082                                      struct walk_control *wc,
6083                                      struct btrfs_path *path)
6084 {
6085         u64 bytenr;
6086         u64 generation;
6087         u64 refs;
6088         u64 flags;
6089         u32 nritems;
6090         u32 blocksize;
6091         struct btrfs_key key;
6092         struct extent_buffer *eb;
6093         int ret;
6094         int slot;
6095         int nread = 0;
6096
6097         if (path->slots[wc->level] < wc->reada_slot) {
6098                 wc->reada_count = wc->reada_count * 2 / 3;
6099                 wc->reada_count = max(wc->reada_count, 2);
6100         } else {
6101                 wc->reada_count = wc->reada_count * 3 / 2;
6102                 wc->reada_count = min_t(int, wc->reada_count,
6103                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6104         }
6105
6106         eb = path->nodes[wc->level];
6107         nritems = btrfs_header_nritems(eb);
6108         blocksize = btrfs_level_size(root, wc->level - 1);
6109
6110         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6111                 if (nread >= wc->reada_count)
6112                         break;
6113
6114                 cond_resched();
6115                 bytenr = btrfs_node_blockptr(eb, slot);
6116                 generation = btrfs_node_ptr_generation(eb, slot);
6117
6118                 if (slot == path->slots[wc->level])
6119                         goto reada;
6120
6121                 if (wc->stage == UPDATE_BACKREF &&
6122                     generation <= root->root_key.offset)
6123                         continue;
6124
6125                 /* We don't lock the tree block, it's OK to be racy here */
6126                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6127                                                &refs, &flags);
6128                 BUG_ON(ret);
6129                 BUG_ON(refs == 0);
6130
6131                 if (wc->stage == DROP_REFERENCE) {
6132                         if (refs == 1)
6133                                 goto reada;
6134
6135                         if (wc->level == 1 &&
6136                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6137                                 continue;
6138                         if (!wc->update_ref ||
6139                             generation <= root->root_key.offset)
6140                                 continue;
6141                         btrfs_node_key_to_cpu(eb, &key, slot);
6142                         ret = btrfs_comp_cpu_keys(&key,
6143                                                   &wc->update_progress);
6144                         if (ret < 0)
6145                                 continue;
6146                 } else {
6147                         if (wc->level == 1 &&
6148                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6149                                 continue;
6150                 }
6151 reada:
6152                 ret = readahead_tree_block(root, bytenr, blocksize,
6153                                            generation);
6154                 if (ret)
6155                         break;
6156                 nread++;
6157         }
6158         wc->reada_slot = slot;
6159 }
6160
6161 /*
6162  * hepler to process tree block while walking down the tree.
6163  *
6164  * when wc->stage == UPDATE_BACKREF, this function updates
6165  * back refs for pointers in the block.
6166  *
6167  * NOTE: return value 1 means we should stop walking down.
6168  */
6169 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
6170                                    struct btrfs_root *root,
6171                                    struct btrfs_path *path,
6172                                    struct walk_control *wc, int lookup_info)
6173 {
6174         int level = wc->level;
6175         struct extent_buffer *eb = path->nodes[level];
6176         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6177         int ret;
6178
6179         if (wc->stage == UPDATE_BACKREF &&
6180             btrfs_header_owner(eb) != root->root_key.objectid)
6181                 return 1;
6182
6183         /*
6184          * when reference count of tree block is 1, it won't increase
6185          * again. once full backref flag is set, we never clear it.
6186          */
6187         if (lookup_info &&
6188             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
6189              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
6190                 BUG_ON(!path->locks[level]);
6191                 ret = btrfs_lookup_extent_info(trans, root,
6192                                                eb->start, eb->len,
6193                                                &wc->refs[level],
6194                                                &wc->flags[level]);
6195                 BUG_ON(ret);
6196                 BUG_ON(wc->refs[level] == 0);
6197         }
6198
6199         if (wc->stage == DROP_REFERENCE) {
6200                 if (wc->refs[level] > 1)
6201                         return 1;
6202
6203                 if (path->locks[level] && !wc->keep_locks) {
6204                         btrfs_tree_unlock_rw(eb, path->locks[level]);
6205                         path->locks[level] = 0;
6206                 }
6207                 return 0;
6208         }
6209
6210         /* wc->stage == UPDATE_BACKREF */
6211         if (!(wc->flags[level] & flag)) {
6212                 BUG_ON(!path->locks[level]);
6213                 ret = btrfs_inc_ref(trans, root, eb, 1);
6214                 BUG_ON(ret);
6215                 ret = btrfs_dec_ref(trans, root, eb, 0);
6216                 BUG_ON(ret);
6217                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
6218                                                   eb->len, flag, 0);
6219                 BUG_ON(ret);
6220                 wc->flags[level] |= flag;
6221         }
6222
6223         /*
6224          * the block is shared by multiple trees, so it's not good to
6225          * keep the tree lock
6226          */
6227         if (path->locks[level] && level > 0) {
6228                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6229                 path->locks[level] = 0;
6230         }
6231         return 0;
6232 }
6233
6234 /*
6235  * hepler to process tree block pointer.
6236  *
6237  * when wc->stage == DROP_REFERENCE, this function checks
6238  * reference count of the block pointed to. if the block
6239  * is shared and we need update back refs for the subtree
6240  * rooted at the block, this function changes wc->stage to
6241  * UPDATE_BACKREF. if the block is shared and there is no
6242  * need to update back, this function drops the reference
6243  * to the block.
6244  *
6245  * NOTE: return value 1 means we should stop walking down.
6246  */
6247 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
6248                                  struct btrfs_root *root,
6249                                  struct btrfs_path *path,
6250                                  struct walk_control *wc, int *lookup_info)
6251 {
6252         u64 bytenr;
6253         u64 generation;
6254         u64 parent;
6255         u32 blocksize;
6256         struct btrfs_key key;
6257         struct extent_buffer *next;
6258         int level = wc->level;
6259         int reada = 0;
6260         int ret = 0;
6261
6262         generation = btrfs_node_ptr_generation(path->nodes[level],
6263                                                path->slots[level]);
6264         /*
6265          * if the lower level block was created before the snapshot
6266          * was created, we know there is no need to update back refs
6267          * for the subtree
6268          */
6269         if (wc->stage == UPDATE_BACKREF &&
6270             generation <= root->root_key.offset) {
6271                 *lookup_info = 1;
6272                 return 1;
6273         }
6274
6275         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6276         blocksize = btrfs_level_size(root, level - 1);
6277
6278         next = btrfs_find_tree_block(root, bytenr, blocksize);
6279         if (!next) {
6280                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6281                 if (!next)
6282                         return -ENOMEM;
6283                 reada = 1;
6284         }
6285         btrfs_tree_lock(next);
6286         btrfs_set_lock_blocking(next);
6287
6288         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6289                                        &wc->refs[level - 1],
6290                                        &wc->flags[level - 1]);
6291         BUG_ON(ret);
6292         BUG_ON(wc->refs[level - 1] == 0);
6293         *lookup_info = 0;
6294
6295         if (wc->stage == DROP_REFERENCE) {
6296                 if (wc->refs[level - 1] > 1) {
6297                         if (level == 1 &&
6298                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6299                                 goto skip;
6300
6301                         if (!wc->update_ref ||
6302                             generation <= root->root_key.offset)
6303                                 goto skip;
6304
6305                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6306                                               path->slots[level]);
6307                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6308                         if (ret < 0)
6309                                 goto skip;
6310
6311                         wc->stage = UPDATE_BACKREF;
6312                         wc->shared_level = level - 1;
6313                 }
6314         } else {
6315                 if (level == 1 &&
6316                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6317                         goto skip;
6318         }
6319
6320         if (!btrfs_buffer_uptodate(next, generation)) {
6321                 btrfs_tree_unlock(next);
6322                 free_extent_buffer(next);
6323                 next = NULL;
6324                 *lookup_info = 1;
6325         }
6326
6327         if (!next) {
6328                 if (reada && level == 1)
6329                         reada_walk_down(trans, root, wc, path);
6330                 next = read_tree_block(root, bytenr, blocksize, generation);
6331                 if (!next)
6332                         return -EIO;
6333                 btrfs_tree_lock(next);
6334                 btrfs_set_lock_blocking(next);
6335         }
6336
6337         level--;
6338         BUG_ON(level != btrfs_header_level(next));
6339         path->nodes[level] = next;
6340         path->slots[level] = 0;
6341         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6342         wc->level = level;
6343         if (wc->level == 1)
6344                 wc->reada_slot = 0;
6345         return 0;
6346 skip:
6347         wc->refs[level - 1] = 0;
6348         wc->flags[level - 1] = 0;
6349         if (wc->stage == DROP_REFERENCE) {
6350                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6351                         parent = path->nodes[level]->start;
6352                 } else {
6353                         BUG_ON(root->root_key.objectid !=
6354                                btrfs_header_owner(path->nodes[level]));
6355                         parent = 0;
6356                 }
6357
6358                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6359                                         root->root_key.objectid, level - 1, 0);
6360                 BUG_ON(ret);
6361         }
6362         btrfs_tree_unlock(next);
6363         free_extent_buffer(next);
6364         *lookup_info = 1;
6365         return 1;
6366 }
6367
6368 /*
6369  * hepler to process tree block while walking up the tree.
6370  *
6371  * when wc->stage == DROP_REFERENCE, this function drops
6372  * reference count on the block.
6373  *
6374  * when wc->stage == UPDATE_BACKREF, this function changes
6375  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6376  * to UPDATE_BACKREF previously while processing the block.
6377  *
6378  * NOTE: return value 1 means we should stop walking up.
6379  */
6380 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6381                                  struct btrfs_root *root,
6382                                  struct btrfs_path *path,
6383                                  struct walk_control *wc)
6384 {
6385         int ret;
6386         int level = wc->level;
6387         struct extent_buffer *eb = path->nodes[level];
6388         u64 parent = 0;
6389
6390         if (wc->stage == UPDATE_BACKREF) {
6391                 BUG_ON(wc->shared_level < level);
6392                 if (level < wc->shared_level)
6393                         goto out;
6394
6395                 ret = find_next_key(path, level + 1, &wc->update_progress);
6396                 if (ret > 0)
6397                         wc->update_ref = 0;
6398
6399                 wc->stage = DROP_REFERENCE;
6400                 wc->shared_level = -1;
6401                 path->slots[level] = 0;
6402
6403                 /*
6404                  * check reference count again if the block isn't locked.
6405                  * we should start walking down the tree again if reference
6406                  * count is one.
6407                  */
6408                 if (!path->locks[level]) {
6409                         BUG_ON(level == 0);
6410                         btrfs_tree_lock(eb);
6411                         btrfs_set_lock_blocking(eb);
6412                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6413
6414                         ret = btrfs_lookup_extent_info(trans, root,
6415                                                        eb->start, eb->len,
6416                                                        &wc->refs[level],
6417                                                        &wc->flags[level]);
6418                         BUG_ON(ret);
6419                         BUG_ON(wc->refs[level] == 0);
6420                         if (wc->refs[level] == 1) {
6421                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6422                                 return 1;
6423                         }
6424                 }
6425         }
6426
6427         /* wc->stage == DROP_REFERENCE */
6428         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6429
6430         if (wc->refs[level] == 1) {
6431                 if (level == 0) {
6432                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6433                                 ret = btrfs_dec_ref(trans, root, eb, 1);
6434                         else
6435                                 ret = btrfs_dec_ref(trans, root, eb, 0);
6436                         BUG_ON(ret);
6437                 }
6438                 /* make block locked assertion in clean_tree_block happy */
6439                 if (!path->locks[level] &&
6440                     btrfs_header_generation(eb) == trans->transid) {
6441                         btrfs_tree_lock(eb);
6442                         btrfs_set_lock_blocking(eb);
6443                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6444                 }
6445                 clean_tree_block(trans, root, eb);
6446         }
6447
6448         if (eb == root->node) {
6449                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6450                         parent = eb->start;
6451                 else
6452                         BUG_ON(root->root_key.objectid !=
6453                                btrfs_header_owner(eb));
6454         } else {
6455                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6456                         parent = path->nodes[level + 1]->start;
6457                 else
6458                         BUG_ON(root->root_key.objectid !=
6459                                btrfs_header_owner(path->nodes[level + 1]));
6460         }
6461
6462         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
6463 out:
6464         wc->refs[level] = 0;
6465         wc->flags[level] = 0;
6466         return 0;
6467 }
6468
6469 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6470                                    struct btrfs_root *root,
6471                                    struct btrfs_path *path,
6472                                    struct walk_control *wc)
6473 {
6474         int level = wc->level;
6475         int lookup_info = 1;
6476         int ret;
6477
6478         while (level >= 0) {
6479                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6480                 if (ret > 0)
6481                         break;
6482
6483                 if (level == 0)
6484                         break;
6485
6486                 if (path->slots[level] >=
6487                     btrfs_header_nritems(path->nodes[level]))
6488                         break;
6489
6490                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6491                 if (ret > 0) {
6492                         path->slots[level]++;
6493                         continue;
6494                 } else if (ret < 0)
6495                         return ret;
6496                 level = wc->level;
6497         }
6498         return 0;
6499 }
6500
6501 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6502                                  struct btrfs_root *root,
6503                                  struct btrfs_path *path,
6504                                  struct walk_control *wc, int max_level)
6505 {
6506         int level = wc->level;
6507         int ret;
6508
6509         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6510         while (level < max_level && path->nodes[level]) {
6511                 wc->level = level;
6512                 if (path->slots[level] + 1 <
6513                     btrfs_header_nritems(path->nodes[level])) {
6514                         path->slots[level]++;
6515                         return 0;
6516                 } else {
6517                         ret = walk_up_proc(trans, root, path, wc);
6518                         if (ret > 0)
6519                                 return 0;
6520
6521                         if (path->locks[level]) {
6522                                 btrfs_tree_unlock_rw(path->nodes[level],
6523                                                      path->locks[level]);
6524                                 path->locks[level] = 0;
6525                         }
6526                         free_extent_buffer(path->nodes[level]);
6527                         path->nodes[level] = NULL;
6528                         level++;
6529                 }
6530         }
6531         return 1;
6532 }
6533
6534 /*
6535  * drop a subvolume tree.
6536  *
6537  * this function traverses the tree freeing any blocks that only
6538  * referenced by the tree.
6539  *
6540  * when a shared tree block is found. this function decreases its
6541  * reference count by one. if update_ref is true, this function
6542  * also make sure backrefs for the shared block and all lower level
6543  * blocks are properly updated.
6544  */
6545 void btrfs_drop_snapshot(struct btrfs_root *root,
6546                          struct btrfs_block_rsv *block_rsv, int update_ref)
6547 {
6548         struct btrfs_path *path;
6549         struct btrfs_trans_handle *trans;
6550         struct btrfs_root *tree_root = root->fs_info->tree_root;
6551         struct btrfs_root_item *root_item = &root->root_item;
6552         struct walk_control *wc;
6553         struct btrfs_key key;
6554         int err = 0;
6555         int ret;
6556         int level;
6557
6558         path = btrfs_alloc_path();
6559         if (!path) {
6560                 err = -ENOMEM;
6561                 goto out;
6562         }
6563
6564         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6565         if (!wc) {
6566                 btrfs_free_path(path);
6567                 err = -ENOMEM;
6568                 goto out;
6569         }
6570
6571         trans = btrfs_start_transaction(tree_root, 0);
6572         BUG_ON(IS_ERR(trans));
6573
6574         if (block_rsv)
6575                 trans->block_rsv = block_rsv;
6576
6577         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6578                 level = btrfs_header_level(root->node);
6579                 path->nodes[level] = btrfs_lock_root_node(root);
6580                 btrfs_set_lock_blocking(path->nodes[level]);
6581                 path->slots[level] = 0;
6582                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6583                 memset(&wc->update_progress, 0,
6584                        sizeof(wc->update_progress));
6585         } else {
6586                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6587                 memcpy(&wc->update_progress, &key,
6588                        sizeof(wc->update_progress));
6589
6590                 level = root_item->drop_level;
6591                 BUG_ON(level == 0);
6592                 path->lowest_level = level;
6593                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6594                 path->lowest_level = 0;
6595                 if (ret < 0) {
6596                         err = ret;
6597                         goto out_free;
6598                 }
6599                 WARN_ON(ret > 0);
6600
6601                 /*
6602                  * unlock our path, this is safe because only this
6603                  * function is allowed to delete this snapshot
6604                  */
6605                 btrfs_unlock_up_safe(path, 0);
6606
6607                 level = btrfs_header_level(root->node);
6608                 while (1) {
6609                         btrfs_tree_lock(path->nodes[level]);
6610                         btrfs_set_lock_blocking(path->nodes[level]);
6611
6612                         ret = btrfs_lookup_extent_info(trans, root,
6613                                                 path->nodes[level]->start,
6614                                                 path->nodes[level]->len,
6615                                                 &wc->refs[level],
6616                                                 &wc->flags[level]);
6617                         BUG_ON(ret);
6618                         BUG_ON(wc->refs[level] == 0);
6619
6620                         if (level == root_item->drop_level)
6621                                 break;
6622
6623                         btrfs_tree_unlock(path->nodes[level]);
6624                         WARN_ON(wc->refs[level] != 1);
6625                         level--;
6626                 }
6627         }
6628
6629         wc->level = level;
6630         wc->shared_level = -1;
6631         wc->stage = DROP_REFERENCE;
6632         wc->update_ref = update_ref;
6633         wc->keep_locks = 0;
6634         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6635
6636         while (1) {
6637                 ret = walk_down_tree(trans, root, path, wc);
6638                 if (ret < 0) {
6639                         err = ret;
6640                         break;
6641                 }
6642
6643                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
6644                 if (ret < 0) {
6645                         err = ret;
6646                         break;
6647                 }
6648
6649                 if (ret > 0) {
6650                         BUG_ON(wc->stage != DROP_REFERENCE);
6651                         break;
6652                 }
6653
6654                 if (wc->stage == DROP_REFERENCE) {
6655                         level = wc->level;
6656                         btrfs_node_key(path->nodes[level],
6657                                        &root_item->drop_progress,
6658                                        path->slots[level]);
6659                         root_item->drop_level = level;
6660                 }
6661
6662                 BUG_ON(wc->level == 0);
6663                 if (btrfs_should_end_transaction(trans, tree_root)) {
6664                         ret = btrfs_update_root(trans, tree_root,
6665                                                 &root->root_key,
6666                                                 root_item);
6667                         BUG_ON(ret);
6668
6669                         btrfs_end_transaction_throttle(trans, tree_root);
6670                         trans = btrfs_start_transaction(tree_root, 0);
6671                         BUG_ON(IS_ERR(trans));
6672                         if (block_rsv)
6673                                 trans->block_rsv = block_rsv;
6674                 }
6675         }
6676         btrfs_release_path(path);
6677         BUG_ON(err);
6678
6679         ret = btrfs_del_root(trans, tree_root, &root->root_key);
6680         BUG_ON(ret);
6681
6682         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
6683                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
6684                                            NULL, NULL);
6685                 BUG_ON(ret < 0);
6686                 if (ret > 0) {
6687                         /* if we fail to delete the orphan item this time
6688                          * around, it'll get picked up the next time.
6689                          *
6690                          * The most common failure here is just -ENOENT.
6691                          */
6692                         btrfs_del_orphan_item(trans, tree_root,
6693                                               root->root_key.objectid);
6694                 }
6695         }
6696
6697         if (root->in_radix) {
6698                 btrfs_free_fs_root(tree_root->fs_info, root);
6699         } else {
6700                 free_extent_buffer(root->node);
6701                 free_extent_buffer(root->commit_root);
6702                 kfree(root);
6703         }
6704 out_free:
6705         btrfs_end_transaction_throttle(trans, tree_root);
6706         kfree(wc);
6707         btrfs_free_path(path);
6708 out:
6709         if (err)
6710                 btrfs_std_error(root->fs_info, err);
6711         return;
6712 }
6713
6714 /*
6715  * drop subtree rooted at tree block 'node'.
6716  *
6717  * NOTE: this function will unlock and release tree block 'node'
6718  */
6719 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6720                         struct btrfs_root *root,
6721                         struct extent_buffer *node,
6722                         struct extent_buffer *parent)
6723 {
6724         struct btrfs_path *path;
6725         struct walk_control *wc;
6726         int level;
6727         int parent_level;
6728         int ret = 0;
6729         int wret;
6730
6731         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6732
6733         path = btrfs_alloc_path();
6734         if (!path)
6735                 return -ENOMEM;
6736
6737         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6738         if (!wc) {
6739                 btrfs_free_path(path);
6740                 return -ENOMEM;
6741         }
6742
6743         btrfs_assert_tree_locked(parent);
6744         parent_level = btrfs_header_level(parent);
6745         extent_buffer_get(parent);
6746         path->nodes[parent_level] = parent;
6747         path->slots[parent_level] = btrfs_header_nritems(parent);
6748
6749         btrfs_assert_tree_locked(node);
6750         level = btrfs_header_level(node);
6751         path->nodes[level] = node;
6752         path->slots[level] = 0;
6753         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6754
6755         wc->refs[parent_level] = 1;
6756         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6757         wc->level = level;
6758         wc->shared_level = -1;
6759         wc->stage = DROP_REFERENCE;
6760         wc->update_ref = 0;
6761         wc->keep_locks = 1;
6762         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6763
6764         while (1) {
6765                 wret = walk_down_tree(trans, root, path, wc);
6766                 if (wret < 0) {
6767                         ret = wret;
6768                         break;
6769                 }
6770
6771                 wret = walk_up_tree(trans, root, path, wc, parent_level);
6772                 if (wret < 0)
6773                         ret = wret;
6774                 if (wret != 0)
6775                         break;
6776         }
6777
6778         kfree(wc);
6779         btrfs_free_path(path);
6780         return ret;
6781 }
6782
6783 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
6784 {
6785         u64 num_devices;
6786         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
6787                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
6788
6789         /*
6790          * we add in the count of missing devices because we want
6791          * to make sure that any RAID levels on a degraded FS
6792          * continue to be honored.
6793          */
6794         num_devices = root->fs_info->fs_devices->rw_devices +
6795                 root->fs_info->fs_devices->missing_devices;
6796
6797         if (num_devices == 1) {
6798                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6799                 stripped = flags & ~stripped;
6800
6801                 /* turn raid0 into single device chunks */
6802                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
6803                         return stripped;
6804
6805                 /* turn mirroring into duplication */
6806                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
6807                              BTRFS_BLOCK_GROUP_RAID10))
6808                         return stripped | BTRFS_BLOCK_GROUP_DUP;
6809                 return flags;
6810         } else {
6811                 /* they already had raid on here, just return */
6812                 if (flags & stripped)
6813                         return flags;
6814
6815                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6816                 stripped = flags & ~stripped;
6817
6818                 /* switch duplicated blocks with raid1 */
6819                 if (flags & BTRFS_BLOCK_GROUP_DUP)
6820                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
6821
6822                 /* turn single device chunks into raid0 */
6823                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
6824         }
6825         return flags;
6826 }
6827
6828 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
6829 {
6830         struct btrfs_space_info *sinfo = cache->space_info;
6831         u64 num_bytes;
6832         u64 min_allocable_bytes;
6833         int ret = -ENOSPC;
6834
6835
6836         /*
6837          * We need some metadata space and system metadata space for
6838          * allocating chunks in some corner cases until we force to set
6839          * it to be readonly.
6840          */
6841         if ((sinfo->flags &
6842              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
6843             !force)
6844                 min_allocable_bytes = 1 * 1024 * 1024;
6845         else
6846                 min_allocable_bytes = 0;
6847
6848         spin_lock(&sinfo->lock);
6849         spin_lock(&cache->lock);
6850
6851         if (cache->ro) {
6852                 ret = 0;
6853                 goto out;
6854         }
6855
6856         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
6857                     cache->bytes_super - btrfs_block_group_used(&cache->item);
6858
6859         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
6860             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
6861             min_allocable_bytes <= sinfo->total_bytes) {
6862                 sinfo->bytes_readonly += num_bytes;
6863                 cache->ro = 1;
6864                 ret = 0;
6865         }
6866 out:
6867         spin_unlock(&cache->lock);
6868         spin_unlock(&sinfo->lock);
6869         return ret;
6870 }
6871
6872 int btrfs_set_block_group_ro(struct btrfs_root *root,
6873                              struct btrfs_block_group_cache *cache)
6874
6875 {
6876         struct btrfs_trans_handle *trans;
6877         u64 alloc_flags;
6878         int ret;
6879
6880         BUG_ON(cache->ro);
6881
6882         trans = btrfs_join_transaction(root);
6883         BUG_ON(IS_ERR(trans));
6884
6885         alloc_flags = update_block_group_flags(root, cache->flags);
6886         if (alloc_flags != cache->flags)
6887                 do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6888                                CHUNK_ALLOC_FORCE);
6889
6890         ret = set_block_group_ro(cache, 0);
6891         if (!ret)
6892                 goto out;
6893         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
6894         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6895                              CHUNK_ALLOC_FORCE);
6896         if (ret < 0)
6897                 goto out;
6898         ret = set_block_group_ro(cache, 0);
6899 out:
6900         btrfs_end_transaction(trans, root);
6901         return ret;
6902 }
6903
6904 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
6905                             struct btrfs_root *root, u64 type)
6906 {
6907         u64 alloc_flags = get_alloc_profile(root, type);
6908         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6909                               CHUNK_ALLOC_FORCE);
6910 }
6911
6912 /*
6913  * helper to account the unused space of all the readonly block group in the
6914  * list. takes mirrors into account.
6915  */
6916 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
6917 {
6918         struct btrfs_block_group_cache *block_group;
6919         u64 free_bytes = 0;
6920         int factor;
6921
6922         list_for_each_entry(block_group, groups_list, list) {
6923                 spin_lock(&block_group->lock);
6924
6925                 if (!block_group->ro) {
6926                         spin_unlock(&block_group->lock);
6927                         continue;
6928                 }
6929
6930                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
6931                                           BTRFS_BLOCK_GROUP_RAID10 |
6932                                           BTRFS_BLOCK_GROUP_DUP))
6933                         factor = 2;
6934                 else
6935                         factor = 1;
6936
6937                 free_bytes += (block_group->key.offset -
6938                                btrfs_block_group_used(&block_group->item)) *
6939                                factor;
6940
6941                 spin_unlock(&block_group->lock);
6942         }
6943
6944         return free_bytes;
6945 }
6946
6947 /*
6948  * helper to account the unused space of all the readonly block group in the
6949  * space_info. takes mirrors into account.
6950  */
6951 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
6952 {
6953         int i;
6954         u64 free_bytes = 0;
6955
6956         spin_lock(&sinfo->lock);
6957
6958         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
6959                 if (!list_empty(&sinfo->block_groups[i]))
6960                         free_bytes += __btrfs_get_ro_block_group_free_space(
6961                                                 &sinfo->block_groups[i]);
6962
6963         spin_unlock(&sinfo->lock);
6964
6965         return free_bytes;
6966 }
6967
6968 int btrfs_set_block_group_rw(struct btrfs_root *root,
6969                               struct btrfs_block_group_cache *cache)
6970 {
6971         struct btrfs_space_info *sinfo = cache->space_info;
6972         u64 num_bytes;
6973
6974         BUG_ON(!cache->ro);
6975
6976         spin_lock(&sinfo->lock);
6977         spin_lock(&cache->lock);
6978         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
6979                     cache->bytes_super - btrfs_block_group_used(&cache->item);
6980         sinfo->bytes_readonly -= num_bytes;
6981         cache->ro = 0;
6982         spin_unlock(&cache->lock);
6983         spin_unlock(&sinfo->lock);
6984         return 0;
6985 }
6986
6987 /*
6988  * checks to see if its even possible to relocate this block group.
6989  *
6990  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
6991  * ok to go ahead and try.
6992  */
6993 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
6994 {
6995         struct btrfs_block_group_cache *block_group;
6996         struct btrfs_space_info *space_info;
6997         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6998         struct btrfs_device *device;
6999         u64 min_free;
7000         u64 dev_min = 1;
7001         u64 dev_nr = 0;
7002         int index;
7003         int full = 0;
7004         int ret = 0;
7005
7006         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7007
7008         /* odd, couldn't find the block group, leave it alone */
7009         if (!block_group)
7010                 return -1;
7011
7012         min_free = btrfs_block_group_used(&block_group->item);
7013
7014         /* no bytes used, we're good */
7015         if (!min_free)
7016                 goto out;
7017
7018         space_info = block_group->space_info;
7019         spin_lock(&space_info->lock);
7020
7021         full = space_info->full;
7022
7023         /*
7024          * if this is the last block group we have in this space, we can't
7025          * relocate it unless we're able to allocate a new chunk below.
7026          *
7027          * Otherwise, we need to make sure we have room in the space to handle
7028          * all of the extents from this block group.  If we can, we're good
7029          */
7030         if ((space_info->total_bytes != block_group->key.offset) &&
7031             (space_info->bytes_used + space_info->bytes_reserved +
7032              space_info->bytes_pinned + space_info->bytes_readonly +
7033              min_free < space_info->total_bytes)) {
7034                 spin_unlock(&space_info->lock);
7035                 goto out;
7036         }
7037         spin_unlock(&space_info->lock);
7038
7039         /*
7040          * ok we don't have enough space, but maybe we have free space on our
7041          * devices to allocate new chunks for relocation, so loop through our
7042          * alloc devices and guess if we have enough space.  However, if we
7043          * were marked as full, then we know there aren't enough chunks, and we
7044          * can just return.
7045          */
7046         ret = -1;
7047         if (full)
7048                 goto out;
7049
7050         /*
7051          * index:
7052          *      0: raid10
7053          *      1: raid1
7054          *      2: dup
7055          *      3: raid0
7056          *      4: single
7057          */
7058         index = get_block_group_index(block_group);
7059         if (index == 0) {
7060                 dev_min = 4;
7061                 /* Divide by 2 */
7062                 min_free >>= 1;
7063         } else if (index == 1) {
7064                 dev_min = 2;
7065         } else if (index == 2) {
7066                 /* Multiply by 2 */
7067                 min_free <<= 1;
7068         } else if (index == 3) {
7069                 dev_min = fs_devices->rw_devices;
7070                 do_div(min_free, dev_min);
7071         }
7072
7073         mutex_lock(&root->fs_info->chunk_mutex);
7074         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7075                 u64 dev_offset;
7076
7077                 /*
7078                  * check to make sure we can actually find a chunk with enough
7079                  * space to fit our block group in.
7080                  */
7081                 if (device->total_bytes > device->bytes_used + min_free) {
7082                         ret = find_free_dev_extent(NULL, device, min_free,
7083                                                    &dev_offset, NULL);
7084                         if (!ret)
7085                                 dev_nr++;
7086
7087                         if (dev_nr >= dev_min)
7088                                 break;
7089
7090                         ret = -1;
7091                 }
7092         }
7093         mutex_unlock(&root->fs_info->chunk_mutex);
7094 out:
7095         btrfs_put_block_group(block_group);
7096         return ret;
7097 }
7098
7099 static int find_first_block_group(struct btrfs_root *root,
7100                 struct btrfs_path *path, struct btrfs_key *key)
7101 {
7102         int ret = 0;
7103         struct btrfs_key found_key;
7104         struct extent_buffer *leaf;
7105         int slot;
7106
7107         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7108         if (ret < 0)
7109                 goto out;
7110
7111         while (1) {
7112                 slot = path->slots[0];
7113                 leaf = path->nodes[0];
7114                 if (slot >= btrfs_header_nritems(leaf)) {
7115                         ret = btrfs_next_leaf(root, path);
7116                         if (ret == 0)
7117                                 continue;
7118                         if (ret < 0)
7119                                 goto out;
7120                         break;
7121                 }
7122                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7123
7124                 if (found_key.objectid >= key->objectid &&
7125                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7126                         ret = 0;
7127                         goto out;
7128                 }
7129                 path->slots[0]++;
7130         }
7131 out:
7132         return ret;
7133 }
7134
7135 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7136 {
7137         struct btrfs_block_group_cache *block_group;
7138         u64 last = 0;
7139
7140         while (1) {
7141                 struct inode *inode;
7142
7143                 block_group = btrfs_lookup_first_block_group(info, last);
7144                 while (block_group) {
7145                         spin_lock(&block_group->lock);
7146                         if (block_group->iref)
7147                                 break;
7148                         spin_unlock(&block_group->lock);
7149                         block_group = next_block_group(info->tree_root,
7150                                                        block_group);
7151                 }
7152                 if (!block_group) {
7153                         if (last == 0)
7154                                 break;
7155                         last = 0;
7156                         continue;
7157                 }
7158
7159                 inode = block_group->inode;
7160                 block_group->iref = 0;
7161                 block_group->inode = NULL;
7162                 spin_unlock(&block_group->lock);
7163                 iput(inode);
7164                 last = block_group->key.objectid + block_group->key.offset;
7165                 btrfs_put_block_group(block_group);
7166         }
7167 }
7168
7169 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7170 {
7171         struct btrfs_block_group_cache *block_group;
7172         struct btrfs_space_info *space_info;
7173         struct btrfs_caching_control *caching_ctl;
7174         struct rb_node *n;
7175
7176         down_write(&info->extent_commit_sem);
7177         while (!list_empty(&info->caching_block_groups)) {
7178                 caching_ctl = list_entry(info->caching_block_groups.next,
7179                                          struct btrfs_caching_control, list);
7180                 list_del(&caching_ctl->list);
7181                 put_caching_control(caching_ctl);
7182         }
7183         up_write(&info->extent_commit_sem);
7184
7185         spin_lock(&info->block_group_cache_lock);
7186         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7187                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7188                                        cache_node);
7189                 rb_erase(&block_group->cache_node,
7190                          &info->block_group_cache_tree);
7191                 spin_unlock(&info->block_group_cache_lock);
7192
7193                 down_write(&block_group->space_info->groups_sem);
7194                 list_del(&block_group->list);
7195                 up_write(&block_group->space_info->groups_sem);
7196
7197                 if (block_group->cached == BTRFS_CACHE_STARTED)
7198                         wait_block_group_cache_done(block_group);
7199
7200                 /*
7201                  * We haven't cached this block group, which means we could
7202                  * possibly have excluded extents on this block group.
7203                  */
7204                 if (block_group->cached == BTRFS_CACHE_NO)
7205                         free_excluded_extents(info->extent_root, block_group);
7206
7207                 btrfs_remove_free_space_cache(block_group);
7208                 btrfs_put_block_group(block_group);
7209
7210                 spin_lock(&info->block_group_cache_lock);
7211         }
7212         spin_unlock(&info->block_group_cache_lock);
7213
7214         /* now that all the block groups are freed, go through and
7215          * free all the space_info structs.  This is only called during
7216          * the final stages of unmount, and so we know nobody is
7217          * using them.  We call synchronize_rcu() once before we start,
7218          * just to be on the safe side.
7219          */
7220         synchronize_rcu();
7221
7222         release_global_block_rsv(info);
7223
7224         while(!list_empty(&info->space_info)) {
7225                 space_info = list_entry(info->space_info.next,
7226                                         struct btrfs_space_info,
7227                                         list);
7228                 if (space_info->bytes_pinned > 0 ||
7229                     space_info->bytes_reserved > 0 ||
7230                     space_info->bytes_may_use > 0) {
7231                         WARN_ON(1);
7232                         dump_space_info(space_info, 0, 0);
7233                 }
7234                 list_del(&space_info->list);
7235                 kfree(space_info);
7236         }
7237         return 0;
7238 }
7239
7240 static void __link_block_group(struct btrfs_space_info *space_info,
7241                                struct btrfs_block_group_cache *cache)
7242 {
7243         int index = get_block_group_index(cache);
7244
7245         down_write(&space_info->groups_sem);
7246         list_add_tail(&cache->list, &space_info->block_groups[index]);
7247         up_write(&space_info->groups_sem);
7248 }
7249
7250 int btrfs_read_block_groups(struct btrfs_root *root)
7251 {
7252         struct btrfs_path *path;
7253         int ret;
7254         struct btrfs_block_group_cache *cache;
7255         struct btrfs_fs_info *info = root->fs_info;
7256         struct btrfs_space_info *space_info;
7257         struct btrfs_key key;
7258         struct btrfs_key found_key;
7259         struct extent_buffer *leaf;
7260         int need_clear = 0;
7261         u64 cache_gen;
7262
7263         root = info->extent_root;
7264         key.objectid = 0;
7265         key.offset = 0;
7266         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
7267         path = btrfs_alloc_path();
7268         if (!path)
7269                 return -ENOMEM;
7270         path->reada = 1;
7271
7272         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
7273         if (btrfs_test_opt(root, SPACE_CACHE) &&
7274             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
7275                 need_clear = 1;
7276         if (btrfs_test_opt(root, CLEAR_CACHE))
7277                 need_clear = 1;
7278
7279         while (1) {
7280                 ret = find_first_block_group(root, path, &key);
7281                 if (ret > 0)
7282                         break;
7283                 if (ret != 0)
7284                         goto error;
7285                 leaf = path->nodes[0];
7286                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
7287                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
7288                 if (!cache) {
7289                         ret = -ENOMEM;
7290                         goto error;
7291                 }
7292                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7293                                                 GFP_NOFS);
7294                 if (!cache->free_space_ctl) {
7295                         kfree(cache);
7296                         ret = -ENOMEM;
7297                         goto error;
7298                 }
7299
7300                 atomic_set(&cache->count, 1);
7301                 spin_lock_init(&cache->lock);
7302                 cache->fs_info = info;
7303                 INIT_LIST_HEAD(&cache->list);
7304                 INIT_LIST_HEAD(&cache->cluster_list);
7305
7306                 if (need_clear)
7307                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7308
7309                 read_extent_buffer(leaf, &cache->item,
7310                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7311                                    sizeof(cache->item));
7312                 memcpy(&cache->key, &found_key, sizeof(found_key));
7313
7314                 key.objectid = found_key.objectid + found_key.offset;
7315                 btrfs_release_path(path);
7316                 cache->flags = btrfs_block_group_flags(&cache->item);
7317                 cache->sectorsize = root->sectorsize;
7318
7319                 btrfs_init_free_space_ctl(cache);
7320
7321                 /*
7322                  * We need to exclude the super stripes now so that the space
7323                  * info has super bytes accounted for, otherwise we'll think
7324                  * we have more space than we actually do.
7325                  */
7326                 exclude_super_stripes(root, cache);
7327
7328                 /*
7329                  * check for two cases, either we are full, and therefore
7330                  * don't need to bother with the caching work since we won't
7331                  * find any space, or we are empty, and we can just add all
7332                  * the space in and be done with it.  This saves us _alot_ of
7333                  * time, particularly in the full case.
7334                  */
7335                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7336                         cache->last_byte_to_unpin = (u64)-1;
7337                         cache->cached = BTRFS_CACHE_FINISHED;
7338                         free_excluded_extents(root, cache);
7339                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7340                         cache->last_byte_to_unpin = (u64)-1;
7341                         cache->cached = BTRFS_CACHE_FINISHED;
7342                         add_new_free_space(cache, root->fs_info,
7343                                            found_key.objectid,
7344                                            found_key.objectid +
7345                                            found_key.offset);
7346                         free_excluded_extents(root, cache);
7347                 }
7348
7349                 ret = update_space_info(info, cache->flags, found_key.offset,
7350                                         btrfs_block_group_used(&cache->item),
7351                                         &space_info);
7352                 BUG_ON(ret);
7353                 cache->space_info = space_info;
7354                 spin_lock(&cache->space_info->lock);
7355                 cache->space_info->bytes_readonly += cache->bytes_super;
7356                 spin_unlock(&cache->space_info->lock);
7357
7358                 __link_block_group(space_info, cache);
7359
7360                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7361                 BUG_ON(ret);
7362
7363                 set_avail_alloc_bits(root->fs_info, cache->flags);
7364                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7365                         set_block_group_ro(cache, 1);
7366         }
7367
7368         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7369                 if (!(get_alloc_profile(root, space_info->flags) &
7370                       (BTRFS_BLOCK_GROUP_RAID10 |
7371                        BTRFS_BLOCK_GROUP_RAID1 |
7372                        BTRFS_BLOCK_GROUP_DUP)))
7373                         continue;
7374                 /*
7375                  * avoid allocating from un-mirrored block group if there are
7376                  * mirrored block groups.
7377                  */
7378                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7379                         set_block_group_ro(cache, 1);
7380                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7381                         set_block_group_ro(cache, 1);
7382         }
7383
7384         init_global_block_rsv(info);
7385         ret = 0;
7386 error:
7387         btrfs_free_path(path);
7388         return ret;
7389 }
7390
7391 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7392                            struct btrfs_root *root, u64 bytes_used,
7393                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7394                            u64 size)
7395 {
7396         int ret;
7397         struct btrfs_root *extent_root;
7398         struct btrfs_block_group_cache *cache;
7399
7400         extent_root = root->fs_info->extent_root;
7401
7402         root->fs_info->last_trans_log_full_commit = trans->transid;
7403
7404         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7405         if (!cache)
7406                 return -ENOMEM;
7407         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7408                                         GFP_NOFS);
7409         if (!cache->free_space_ctl) {
7410                 kfree(cache);
7411                 return -ENOMEM;
7412         }
7413
7414         cache->key.objectid = chunk_offset;
7415         cache->key.offset = size;
7416         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7417         cache->sectorsize = root->sectorsize;
7418         cache->fs_info = root->fs_info;
7419
7420         atomic_set(&cache->count, 1);
7421         spin_lock_init(&cache->lock);
7422         INIT_LIST_HEAD(&cache->list);
7423         INIT_LIST_HEAD(&cache->cluster_list);
7424
7425         btrfs_init_free_space_ctl(cache);
7426
7427         btrfs_set_block_group_used(&cache->item, bytes_used);
7428         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7429         cache->flags = type;
7430         btrfs_set_block_group_flags(&cache->item, type);
7431
7432         cache->last_byte_to_unpin = (u64)-1;
7433         cache->cached = BTRFS_CACHE_FINISHED;
7434         exclude_super_stripes(root, cache);
7435
7436         add_new_free_space(cache, root->fs_info, chunk_offset,
7437                            chunk_offset + size);
7438
7439         free_excluded_extents(root, cache);
7440
7441         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7442                                 &cache->space_info);
7443         BUG_ON(ret);
7444
7445         spin_lock(&cache->space_info->lock);
7446         cache->space_info->bytes_readonly += cache->bytes_super;
7447         spin_unlock(&cache->space_info->lock);
7448
7449         __link_block_group(cache->space_info, cache);
7450
7451         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7452         BUG_ON(ret);
7453
7454         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7455                                 sizeof(cache->item));
7456         BUG_ON(ret);
7457
7458         set_avail_alloc_bits(extent_root->fs_info, type);
7459
7460         return 0;
7461 }
7462
7463 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7464                              struct btrfs_root *root, u64 group_start)
7465 {
7466         struct btrfs_path *path;
7467         struct btrfs_block_group_cache *block_group;
7468         struct btrfs_free_cluster *cluster;
7469         struct btrfs_root *tree_root = root->fs_info->tree_root;
7470         struct btrfs_key key;
7471         struct inode *inode;
7472         int ret;
7473         int factor;
7474
7475         root = root->fs_info->extent_root;
7476
7477         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7478         BUG_ON(!block_group);
7479         BUG_ON(!block_group->ro);
7480
7481         /*
7482          * Free the reserved super bytes from this block group before
7483          * remove it.
7484          */
7485         free_excluded_extents(root, block_group);
7486
7487         memcpy(&key, &block_group->key, sizeof(key));
7488         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7489                                   BTRFS_BLOCK_GROUP_RAID1 |
7490                                   BTRFS_BLOCK_GROUP_RAID10))
7491                 factor = 2;
7492         else
7493                 factor = 1;
7494
7495         /* make sure this block group isn't part of an allocation cluster */
7496         cluster = &root->fs_info->data_alloc_cluster;
7497         spin_lock(&cluster->refill_lock);
7498         btrfs_return_cluster_to_free_space(block_group, cluster);
7499         spin_unlock(&cluster->refill_lock);
7500
7501         /*
7502          * make sure this block group isn't part of a metadata
7503          * allocation cluster
7504          */
7505         cluster = &root->fs_info->meta_alloc_cluster;
7506         spin_lock(&cluster->refill_lock);
7507         btrfs_return_cluster_to_free_space(block_group, cluster);
7508         spin_unlock(&cluster->refill_lock);
7509
7510         path = btrfs_alloc_path();
7511         if (!path) {
7512                 ret = -ENOMEM;
7513                 goto out;
7514         }
7515
7516         inode = lookup_free_space_inode(tree_root, block_group, path);
7517         if (!IS_ERR(inode)) {
7518                 ret = btrfs_orphan_add(trans, inode);
7519                 BUG_ON(ret);
7520                 clear_nlink(inode);
7521                 /* One for the block groups ref */
7522                 spin_lock(&block_group->lock);
7523                 if (block_group->iref) {
7524                         block_group->iref = 0;
7525                         block_group->inode = NULL;
7526                         spin_unlock(&block_group->lock);
7527                         iput(inode);
7528                 } else {
7529                         spin_unlock(&block_group->lock);
7530                 }
7531                 /* One for our lookup ref */
7532                 btrfs_add_delayed_iput(inode);
7533         }
7534
7535         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7536         key.offset = block_group->key.objectid;
7537         key.type = 0;
7538
7539         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7540         if (ret < 0)
7541                 goto out;
7542         if (ret > 0)
7543                 btrfs_release_path(path);
7544         if (ret == 0) {
7545                 ret = btrfs_del_item(trans, tree_root, path);
7546                 if (ret)
7547                         goto out;
7548                 btrfs_release_path(path);
7549         }
7550
7551         spin_lock(&root->fs_info->block_group_cache_lock);
7552         rb_erase(&block_group->cache_node,
7553                  &root->fs_info->block_group_cache_tree);
7554         spin_unlock(&root->fs_info->block_group_cache_lock);
7555
7556         down_write(&block_group->space_info->groups_sem);
7557         /*
7558          * we must use list_del_init so people can check to see if they
7559          * are still on the list after taking the semaphore
7560          */
7561         list_del_init(&block_group->list);
7562         up_write(&block_group->space_info->groups_sem);
7563
7564         if (block_group->cached == BTRFS_CACHE_STARTED)
7565                 wait_block_group_cache_done(block_group);
7566
7567         btrfs_remove_free_space_cache(block_group);
7568
7569         spin_lock(&block_group->space_info->lock);
7570         block_group->space_info->total_bytes -= block_group->key.offset;
7571         block_group->space_info->bytes_readonly -= block_group->key.offset;
7572         block_group->space_info->disk_total -= block_group->key.offset * factor;
7573         spin_unlock(&block_group->space_info->lock);
7574
7575         memcpy(&key, &block_group->key, sizeof(key));
7576
7577         btrfs_clear_space_info_full(root->fs_info);
7578
7579         btrfs_put_block_group(block_group);
7580         btrfs_put_block_group(block_group);
7581
7582         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
7583         if (ret > 0)
7584                 ret = -EIO;
7585         if (ret < 0)
7586                 goto out;
7587
7588         ret = btrfs_del_item(trans, root, path);
7589 out:
7590         btrfs_free_path(path);
7591         return ret;
7592 }
7593
7594 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
7595 {
7596         struct btrfs_space_info *space_info;
7597         struct btrfs_super_block *disk_super;
7598         u64 features;
7599         u64 flags;
7600         int mixed = 0;
7601         int ret;
7602
7603         disk_super = fs_info->super_copy;
7604         if (!btrfs_super_root(disk_super))
7605                 return 1;
7606
7607         features = btrfs_super_incompat_flags(disk_super);
7608         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
7609                 mixed = 1;
7610
7611         flags = BTRFS_BLOCK_GROUP_SYSTEM;
7612         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7613         if (ret)
7614                 goto out;
7615
7616         if (mixed) {
7617                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
7618                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7619         } else {
7620                 flags = BTRFS_BLOCK_GROUP_METADATA;
7621                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7622                 if (ret)
7623                         goto out;
7624
7625                 flags = BTRFS_BLOCK_GROUP_DATA;
7626                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7627         }
7628 out:
7629         return ret;
7630 }
7631
7632 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
7633 {
7634         return unpin_extent_range(root, start, end);
7635 }
7636
7637 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
7638                                u64 num_bytes, u64 *actual_bytes)
7639 {
7640         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
7641 }
7642
7643 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
7644 {
7645         struct btrfs_fs_info *fs_info = root->fs_info;
7646         struct btrfs_block_group_cache *cache = NULL;
7647         u64 group_trimmed;
7648         u64 start;
7649         u64 end;
7650         u64 trimmed = 0;
7651         int ret = 0;
7652
7653         cache = btrfs_lookup_block_group(fs_info, range->start);
7654
7655         while (cache) {
7656                 if (cache->key.objectid >= (range->start + range->len)) {
7657                         btrfs_put_block_group(cache);
7658                         break;
7659                 }
7660
7661                 start = max(range->start, cache->key.objectid);
7662                 end = min(range->start + range->len,
7663                                 cache->key.objectid + cache->key.offset);
7664
7665                 if (end - start >= range->minlen) {
7666                         if (!block_group_cache_done(cache)) {
7667                                 ret = cache_block_group(cache, NULL, root, 0);
7668                                 if (!ret)
7669                                         wait_block_group_cache_done(cache);
7670                         }
7671                         ret = btrfs_trim_block_group(cache,
7672                                                      &group_trimmed,
7673                                                      start,
7674                                                      end,
7675                                                      range->minlen);
7676
7677                         trimmed += group_trimmed;
7678                         if (ret) {
7679                                 btrfs_put_block_group(cache);
7680                                 break;
7681                         }
7682                 }
7683
7684                 cache = next_block_group(fs_info->tree_root, cache);
7685         }
7686
7687         range->len = trimmed;
7688         return ret;
7689 }