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 "compat.h"
  26 #include "hash.h"
  27 #include "ctree.h"
  28 #include "disk-io.h"
  29 #include "print-tree.h"
  30 #include "transaction.h"
  31 #include "volumes.h"
  32 #include "locking.h"
  33 #include "free-space-cache.h"
  34
  35 static int update_block_group(struct btrfs_trans_handle *trans,
  36                               struct btrfs_root *root,
  37                               u64 bytenr, u64 num_bytes, int alloc,
  38                               int mark_free);
  39 static int update_reserved_extents(struct btrfs_block_group_cache *cache,
  40                                    u64 num_bytes, int reserve);
  41 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  42                                 struct btrfs_root *root,
  43                                 u64 bytenr, u64 num_bytes, u64 parent,
  44                                 u64 root_objectid, u64 owner_objectid,
  45                                 u64 owner_offset, int refs_to_drop,
  46                                 struct btrfs_delayed_extent_op *extra_op);
  47 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  48                                     struct extent_buffer *leaf,
  49                                     struct btrfs_extent_item *ei);
  50 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  51                                       struct btrfs_root *root,
  52                                       u64 parent, u64 root_objectid,
  53                                       u64 flags, u64 owner, u64 offset,
  54                                       struct btrfs_key *ins, int ref_mod);
  55 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  56                                      struct btrfs_root *root,
  57                                      u64 parent, u64 root_objectid,
  58                                      u64 flags, struct btrfs_disk_key *key,
  59                                      int level, struct btrfs_key *ins);
  60 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  61                           struct btrfs_root *extent_root, u64 alloc_bytes,
  62                           u64 flags, int force);
  63 static int pin_down_bytes(struct btrfs_trans_handle *trans,
  64                           struct btrfs_root *root,
  65                           struct btrfs_path *path,
  66                           u64 bytenr, u64 num_bytes,
  67                           int is_data, int reserved,
  68                           struct extent_buffer **must_clean);
  69 static int find_next_key(struct btrfs_path *path, int level,
  70                          struct btrfs_key *key);
  71 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
  72                             int dump_block_groups);
  73
  74 static noinline int
  75 block_group_cache_done(struct btrfs_block_group_cache *cache)
  76 {
  77         smp_mb();
  78         return cache->cached == BTRFS_CACHE_FINISHED;
  79 }
  80
  81 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  82 {
  83         return (cache->flags & bits) == bits;
  84 }
  85
  86 /*
  87  * this adds the block group to the fs_info rb tree for the block group
  88  * cache
  89  */
  90 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
  91                                 struct btrfs_block_group_cache *block_group)
  92 {
  93         struct rb_node **p;
  94         struct rb_node *parent = NULL;
  95         struct btrfs_block_group_cache *cache;
  96
  97         spin_lock(&info->block_group_cache_lock);
  98         p = &info->block_group_cache_tree.rb_node;
  99
 100         while (*p) {
 101                 parent = *p;
 102                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 103                                  cache_node);
 104                 if (block_group->key.objectid < cache->key.objectid) {
 105                         p = &(*p)->rb_left;
 106                 } else if (block_group->key.objectid > cache->key.objectid) {
 107                         p = &(*p)->rb_right;
 108                 } else {
 109                         spin_unlock(&info->block_group_cache_lock);
 110                         return -EEXIST;
 111                 }
 112         }
 113
 114         rb_link_node(&block_group->cache_node, parent, p);
 115         rb_insert_color(&block_group->cache_node,
 116                         &info->block_group_cache_tree);
 117         spin_unlock(&info->block_group_cache_lock);
 118
 119         return 0;
 120 }
 121
 122 /*
 123  * This will return the block group at or after bytenr if contains is 0, else
 124  * it will return the block group that contains the bytenr
 125  */
 126 static struct btrfs_block_group_cache *
 127 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 128                               int contains)
 129 {
 130         struct btrfs_block_group_cache *cache, *ret = NULL;
 131         struct rb_node *n;
 132         u64 end, start;
 133
 134         spin_lock(&info->block_group_cache_lock);
 135         n = info->block_group_cache_tree.rb_node;
 136
 137         while (n) {
 138                 cache = rb_entry(n, struct btrfs_block_group_cache,
 139                                  cache_node);
 140                 end = cache->key.objectid + cache->key.offset - 1;
 141                 start = cache->key.objectid;
 142
 143                 if (bytenr < start) {
 144                         if (!contains && (!ret || start < ret->key.objectid))
 145                                 ret = cache;
 146                         n = n->rb_left;
 147                 } else if (bytenr > start) {
 148                         if (contains && bytenr <= end) {
 149                                 ret = cache;
 150                                 break;
 151                         }
 152                         n = n->rb_right;
 153                 } else {
 154                         ret = cache;
 155                         break;
 156                 }
 157         }
 158         if (ret)
 159                 atomic_inc(&ret->count);
 160         spin_unlock(&info->block_group_cache_lock);
 161
 162         return ret;
 163 }
 164
 165 static int add_excluded_extent(struct btrfs_root *root,
 166                                u64 start, u64 num_bytes)
 167 {
 168         u64 end = start + num_bytes - 1;
 169         set_extent_bits(&root->fs_info->freed_extents[0],
 170                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 171         set_extent_bits(&root->fs_info->freed_extents[1],
 172                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 173         return 0;
 174 }
 175
 176 static void free_excluded_extents(struct btrfs_root *root,
 177                                   struct btrfs_block_group_cache *cache)
 178 {
 179         u64 start, end;
 180
 181         start = cache->key.objectid;
 182         end = start + cache->key.offset - 1;
 183
 184         clear_extent_bits(&root->fs_info->freed_extents[0],
 185                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 186         clear_extent_bits(&root->fs_info->freed_extents[1],
 187                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 188 }
 189
 190 static int exclude_super_stripes(struct btrfs_root *root,
 191                                  struct btrfs_block_group_cache *cache)
 192 {
 193         u64 bytenr;
 194         u64 *logical;
 195         int stripe_len;
 196         int i, nr, ret;
 197
 198         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 199                 bytenr = btrfs_sb_offset(i);
 200                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 201                                        cache->key.objectid, bytenr,
 202                                        0, &logical, &nr, &stripe_len);
 203                 BUG_ON(ret);
 204
 205                 while (nr--) {
 206                         cache->bytes_super += stripe_len;
 207                         ret = add_excluded_extent(root, logical[nr],
 208                                                   stripe_len);
 209                         BUG_ON(ret);
 210                 }
 211
 212                 kfree(logical);
 213         }
 214         return 0;
 215 }
 216
 217 static struct btrfs_caching_control *
 218 get_caching_control(struct btrfs_block_group_cache *cache)
 219 {
 220         struct btrfs_caching_control *ctl;
 221
 222         spin_lock(&cache->lock);
 223         if (cache->cached != BTRFS_CACHE_STARTED) {
 224                 spin_unlock(&cache->lock);
 225                 return NULL;
 226         }
 227
 228         ctl = cache->caching_ctl;
 229         atomic_inc(&ctl->count);
 230         spin_unlock(&cache->lock);
 231         return ctl;
 232 }
 233
 234 static void put_caching_control(struct btrfs_caching_control *ctl)
 235 {
 236         if (atomic_dec_and_test(&ctl->count))
 237                 kfree(ctl);
 238 }
 239
 240 /*
 241  * this is only called by cache_block_group, since we could have freed extents
 242  * we need to check the pinned_extents for any extents that can't be used yet
 243  * since their free space will be released as soon as the transaction commits.
 244  */
 245 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 246                               struct btrfs_fs_info *info, u64 start, u64 end)
 247 {
 248         u64 extent_start, extent_end, size, total_added = 0;
 249         int ret;
 250
 251         while (start < end) {
 252                 ret = find_first_extent_bit(info->pinned_extents, start,
 253                                             &extent_start, &extent_end,
 254                                             EXTENT_DIRTY | EXTENT_UPTODATE);
 255                 if (ret)
 256                         break;
 257
 258                 if (extent_start == start) {
 259                         start = extent_end + 1;
 260                 } else if (extent_start > start && extent_start < end) {
 261                         size = extent_start - start;
 262                         total_added += size;
 263                         ret = btrfs_add_free_space(block_group, start,
 264                                                    size);
 265                         BUG_ON(ret);
 266                         start = extent_end + 1;
 267                 } else {
 268                         break;
 269                 }
 270         }
 271
 272         if (start < end) {
 273                 size = end - start;
 274                 total_added += size;
 275                 ret = btrfs_add_free_space(block_group, start, size);
 276                 BUG_ON(ret);
 277         }
 278
 279         return total_added;
 280 }
 281
 282 static int caching_kthread(void *data)
 283 {
 284         struct btrfs_block_group_cache *block_group = data;
 285         struct btrfs_fs_info *fs_info = block_group->fs_info;
 286         struct btrfs_caching_control *caching_ctl = block_group->caching_ctl;
 287         struct btrfs_root *extent_root = fs_info->extent_root;
 288         struct btrfs_path *path;
 289         struct extent_buffer *leaf;
 290         struct btrfs_key key;
 291         u64 total_found = 0;
 292         u64 last = 0;
 293         u32 nritems;
 294         int ret = 0;
 295
 296         path = btrfs_alloc_path();
 297         if (!path)
 298                 return -ENOMEM;
 299
 300         exclude_super_stripes(extent_root, block_group);
 301         spin_lock(&block_group->space_info->lock);
 302         block_group->space_info->bytes_super += block_group->bytes_super;
 303         spin_unlock(&block_group->space_info->lock);
 304
 305         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 306
 307         /*
 308          * We don't want to deadlock with somebody trying to allocate a new
 309          * extent for the extent root while also trying to search the extent
 310          * root to add free space.  So we skip locking and search the commit
 311          * root, since its read-only
 312          */
 313         path->skip_locking = 1;
 314         path->search_commit_root = 1;
 315         path->reada = 2;
 316
 317         key.objectid = last;
 318         key.offset = 0;
 319         key.type = BTRFS_EXTENT_ITEM_KEY;
 320 again:
 321         mutex_lock(&caching_ctl->mutex);
 322         /* need to make sure the commit_root doesn't disappear */
 323         down_read(&fs_info->extent_commit_sem);
 324
 325         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 326         if (ret < 0)
 327                 goto err;
 328
 329         leaf = path->nodes[0];
 330         nritems = btrfs_header_nritems(leaf);
 331
 332         while (1) {
 333                 smp_mb();
 334                 if (fs_info->closing > 1) {
 335                         last = (u64)-1;
 336                         break;
 337                 }
 338
 339                 if (path->slots[0] < nritems) {
 340                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 341                 } else {
 342                         ret = find_next_key(path, 0, &key);
 343                         if (ret)
 344                                 break;
 345
 346                         caching_ctl->progress = last;
 347                         btrfs_release_path(extent_root, path);
 348                         up_read(&fs_info->extent_commit_sem);
 349                         mutex_unlock(&caching_ctl->mutex);
 350                         if (btrfs_transaction_in_commit(fs_info))
 351                                 schedule_timeout(1);
 352                         else
 353                                 cond_resched();
 354                         goto again;
 355                 }
 356
 357                 if (key.objectid < block_group->key.objectid) {
 358                         path->slots[0]++;
 359                         continue;
 360                 }
 361
 362                 if (key.objectid >= block_group->key.objectid +
 363                     block_group->key.offset)
 364                         break;
 365
 366                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 367                         total_found += add_new_free_space(block_group,
 368                                                           fs_info, last,
 369                                                           key.objectid);
 370                         last = key.objectid + key.offset;
 371
 372                         if (total_found > (1024 * 1024 * 2)) {
 373                                 total_found = 0;
 374                                 wake_up(&caching_ctl->wait);
 375                         }
 376                 }
 377                 path->slots[0]++;
 378         }
 379         ret = 0;
 380
 381         total_found += add_new_free_space(block_group, fs_info, last,
 382                                           block_group->key.objectid +
 383                                           block_group->key.offset);
 384         caching_ctl->progress = (u64)-1;
 385
 386         spin_lock(&block_group->lock);
 387         block_group->caching_ctl = NULL;
 388         block_group->cached = BTRFS_CACHE_FINISHED;
 389         spin_unlock(&block_group->lock);
 390
 391 err:
 392         btrfs_free_path(path);
 393         up_read(&fs_info->extent_commit_sem);
 394
 395         free_excluded_extents(extent_root, block_group);
 396
 397         mutex_unlock(&caching_ctl->mutex);
 398         wake_up(&caching_ctl->wait);
 399
 400         put_caching_control(caching_ctl);
 401         atomic_dec(&block_group->space_info->caching_threads);
 402         return 0;
 403 }
 404
 405 static int cache_block_group(struct btrfs_block_group_cache *cache)
 406 {
 407         struct btrfs_fs_info *fs_info = cache->fs_info;
 408         struct btrfs_caching_control *caching_ctl;
 409         struct task_struct *tsk;
 410         int ret = 0;
 411
 412         smp_mb();
 413         if (cache->cached != BTRFS_CACHE_NO)
 414                 return 0;
 415
 416         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_KERNEL);
 417         BUG_ON(!caching_ctl);
 418
 419         INIT_LIST_HEAD(&caching_ctl->list);
 420         mutex_init(&caching_ctl->mutex);
 421         init_waitqueue_head(&caching_ctl->wait);
 422         caching_ctl->block_group = cache;
 423         caching_ctl->progress = cache->key.objectid;
 424         /* one for caching kthread, one for caching block group list */
 425         atomic_set(&caching_ctl->count, 2);
 426
 427         spin_lock(&cache->lock);
 428         if (cache->cached != BTRFS_CACHE_NO) {
 429                 spin_unlock(&cache->lock);
 430                 kfree(caching_ctl);
 431                 return 0;
 432         }
 433         cache->caching_ctl = caching_ctl;
 434         cache->cached = BTRFS_CACHE_STARTED;
 435         spin_unlock(&cache->lock);
 436
 437         down_write(&fs_info->extent_commit_sem);
 438         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 439         up_write(&fs_info->extent_commit_sem);
 440
 441         atomic_inc(&cache->space_info->caching_threads);
 442
 443         tsk = kthread_run(caching_kthread, cache, "btrfs-cache-%llu\n",
 444                           cache->key.objectid);
 445         if (IS_ERR(tsk)) {
 446                 ret = PTR_ERR(tsk);
 447                 printk(KERN_ERR "error running thread %d\n", ret);
 448                 BUG();
 449         }
 450
 451         return ret;
 452 }
 453
 454 /*
 455  * return the block group that starts at or after bytenr
 456  */
 457 static struct btrfs_block_group_cache *
 458 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 459 {
 460         struct btrfs_block_group_cache *cache;
 461
 462         cache = block_group_cache_tree_search(info, bytenr, 0);
 463
 464         return cache;
 465 }
 466
 467 /*
 468  * return the block group that contains the given bytenr
 469  */
 470 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 471                                                  struct btrfs_fs_info *info,
 472                                                  u64 bytenr)
 473 {
 474         struct btrfs_block_group_cache *cache;
 475
 476         cache = block_group_cache_tree_search(info, bytenr, 1);
 477
 478         return cache;
 479 }
 480
 481 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 482 {
 483         if (atomic_dec_and_test(&cache->count))
 484                 kfree(cache);
 485 }
 486
 487 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 488                                                   u64 flags)
 489 {
 490         struct list_head *head = &info->space_info;
 491         struct btrfs_space_info *found;
 492
 493         rcu_read_lock();
 494         list_for_each_entry_rcu(found, head, list) {
 495                 if (found->flags == flags) {
 496                         rcu_read_unlock();
 497                         return found;
 498                 }
 499         }
 500         rcu_read_unlock();
 501         return NULL;
 502 }
 503
 504 /*
 505  * after adding space to the filesystem, we need to clear the full flags
 506  * on all the space infos.
 507  */
 508 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 509 {
 510         struct list_head *head = &info->space_info;
 511         struct btrfs_space_info *found;
 512
 513         rcu_read_lock();
 514         list_for_each_entry_rcu(found, head, list)
 515                 found->full = 0;
 516         rcu_read_unlock();
 517 }
 518
 519 static u64 div_factor(u64 num, int factor)
 520 {
 521         if (factor == 10)
 522                 return num;
 523         num *= factor;
 524         do_div(num, 10);
 525         return num;
 526 }
 527
 528 u64 btrfs_find_block_group(struct btrfs_root *root,
 529                            u64 search_start, u64 search_hint, int owner)
 530 {
 531         struct btrfs_block_group_cache *cache;
 532         u64 used;
 533         u64 last = max(search_hint, search_start);
 534         u64 group_start = 0;
 535         int full_search = 0;
 536         int factor = 9;
 537         int wrapped = 0;
 538 again:
 539         while (1) {
 540                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 541                 if (!cache)
 542                         break;
 543
 544                 spin_lock(&cache->lock);
 545                 last = cache->key.objectid + cache->key.offset;
 546                 used = btrfs_block_group_used(&cache->item);
 547
 548                 if ((full_search || !cache->ro) &&
 549                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 550                         if (used + cache->pinned + cache->reserved <
 551                             div_factor(cache->key.offset, factor)) {
 552                                 group_start = cache->key.objectid;
 553                                 spin_unlock(&cache->lock);
 554                                 btrfs_put_block_group(cache);
 555                                 goto found;
 556                         }
 557                 }
 558                 spin_unlock(&cache->lock);
 559                 btrfs_put_block_group(cache);
 560                 cond_resched();
 561         }
 562         if (!wrapped) {
 563                 last = search_start;
 564                 wrapped = 1;
 565                 goto again;
 566         }
 567         if (!full_search && factor < 10) {
 568                 last = search_start;
 569                 full_search = 1;
 570                 factor = 10;
 571                 goto again;
 572         }
 573 found:
 574         return group_start;
 575 }
 576
 577 /* simple helper to search for an existing extent at a given offset */
 578 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 579 {
 580         int ret;
 581         struct btrfs_key key;
 582         struct btrfs_path *path;
 583
 584         path = btrfs_alloc_path();
 585         BUG_ON(!path);
 586         key.objectid = start;
 587         key.offset = len;
 588         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 589         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 590                                 0, 0);
 591         btrfs_free_path(path);
 592         return ret;
 593 }
 594
 595 /*
 596  * Back reference rules.  Back refs have three main goals:
 597  *
 598  * 1) differentiate between all holders of references to an extent so that
 599  *    when a reference is dropped we can make sure it was a valid reference
 600  *    before freeing the extent.
 601  *
 602  * 2) Provide enough information to quickly find the holders of an extent
 603  *    if we notice a given block is corrupted or bad.
 604  *
 605  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 606  *    maintenance.  This is actually the same as #2, but with a slightly
 607  *    different use case.
 608  *
 609  * There are two kinds of back refs. The implicit back refs is optimized
 610  * for pointers in non-shared tree blocks. For a given pointer in a block,
 611  * back refs of this kind provide information about the block's owner tree
 612  * and the pointer's key. These information allow us to find the block by
 613  * b-tree searching. The full back refs is for pointers in tree blocks not
 614  * referenced by their owner trees. The location of tree block is recorded
 615  * in the back refs. Actually the full back refs is generic, and can be
 616  * used in all cases the implicit back refs is used. The major shortcoming
 617  * of the full back refs is its overhead. Every time a tree block gets
 618  * COWed, we have to update back refs entry for all pointers in it.
 619  *
 620  * For a newly allocated tree block, we use implicit back refs for
 621  * pointers in it. This means most tree related operations only involve
 622  * implicit back refs. For a tree block created in old transaction, the
 623  * only way to drop a reference to it is COW it. So we can detect the
 624  * event that tree block loses its owner tree's reference and do the
 625  * back refs conversion.
 626  *
 627  * When a tree block is COW'd through a tree, there are four cases:
 628  *
 629  * The reference count of the block is one and the tree is the block's
 630  * owner tree. Nothing to do in this case.
 631  *
 632  * The reference count of the block is one and the tree is not the
 633  * block's owner tree. In this case, full back refs is used for pointers
 634  * in the block. Remove these full back refs, add implicit back refs for
 635  * every pointers in the new block.
 636  *
 637  * The reference count of the block is greater than one and the tree is
 638  * the block's owner tree. In this case, implicit back refs is used for
 639  * pointers in the block. Add full back refs for every pointers in the
 640  * block, increase lower level extents' reference counts. The original
 641  * implicit back refs are entailed to the new block.
 642  *
 643  * The reference count of the block is greater than one and the tree is
 644  * not the block's owner tree. Add implicit back refs for every pointer in
 645  * the new block, increase lower level extents' reference count.
 646  *
 647  * Back Reference Key composing:
 648  *
 649  * The key objectid corresponds to the first byte in the extent,
 650  * The key type is used to differentiate between types of back refs.
 651  * There are different meanings of the key offset for different types
 652  * of back refs.
 653  *
 654  * File extents can be referenced by:
 655  *
 656  * - multiple snapshots, subvolumes, or different generations in one subvol
 657  * - different files inside a single subvolume
 658  * - different offsets inside a file (bookend extents in file.c)
 659  *
 660  * The extent ref structure for the implicit back refs has fields for:
 661  *
 662  * - Objectid of the subvolume root
 663  * - objectid of the file holding the reference
 664  * - original offset in the file
 665  * - how many bookend extents
 666  *
 667  * The key offset for the implicit back refs is hash of the first
 668  * three fields.
 669  *
 670  * The extent ref structure for the full back refs has field for:
 671  *
 672  * - number of pointers in the tree leaf
 673  *
 674  * The key offset for the implicit back refs is the first byte of
 675  * the tree leaf
 676  *
 677  * When a file extent is allocated, The implicit back refs is used.
 678  * the fields are filled in:
 679  *
 680  *     (root_key.objectid, inode objectid, offset in file, 1)
 681  *
 682  * When a file extent is removed file truncation, we find the
 683  * corresponding implicit back refs and check the following fields:
 684  *
 685  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 686  *
 687  * Btree extents can be referenced by:
 688  *
 689  * - Different subvolumes
 690  *
 691  * Both the implicit back refs and the full back refs for tree blocks
 692  * only consist of key. The key offset for the implicit back refs is
 693  * objectid of block's owner tree. The key offset for the full back refs
 694  * is the first byte of parent block.
 695  *
 696  * When implicit back refs is used, information about the lowest key and
 697  * level of the tree block are required. These information are stored in
 698  * tree block info structure.
 699  */
 700
 701 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 702 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 703                                   struct btrfs_root *root,
 704                                   struct btrfs_path *path,
 705                                   u64 owner, u32 extra_size)
 706 {
 707         struct btrfs_extent_item *item;
 708         struct btrfs_extent_item_v0 *ei0;
 709         struct btrfs_extent_ref_v0 *ref0;
 710         struct btrfs_tree_block_info *bi;
 711         struct extent_buffer *leaf;
 712         struct btrfs_key key;
 713         struct btrfs_key found_key;
 714         u32 new_size = sizeof(*item);
 715         u64 refs;
 716         int ret;
 717
 718         leaf = path->nodes[0];
 719         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 720
 721         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 722         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 723                              struct btrfs_extent_item_v0);
 724         refs = btrfs_extent_refs_v0(leaf, ei0);
 725
 726         if (owner == (u64)-1) {
 727                 while (1) {
 728                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 729                                 ret = btrfs_next_leaf(root, path);
 730                                 if (ret < 0)
 731                                         return ret;
 732                                 BUG_ON(ret > 0);
 733                                 leaf = path->nodes[0];
 734                         }
 735                         btrfs_item_key_to_cpu(leaf, &found_key,
 736                                               path->slots[0]);
 737                         BUG_ON(key.objectid != found_key.objectid);
 738                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 739                                 path->slots[0]++;
 740                                 continue;
 741                         }
 742                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 743                                               struct btrfs_extent_ref_v0);
 744                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 745                         break;
 746                 }
 747         }
 748         btrfs_release_path(root, path);
 749
 750         if (owner < BTRFS_FIRST_FREE_OBJECTID)
 751                 new_size += sizeof(*bi);
 752
 753         new_size -= sizeof(*ei0);
 754         ret = btrfs_search_slot(trans, root, &key, path,
 755                                 new_size + extra_size, 1);
 756         if (ret < 0)
 757                 return ret;
 758         BUG_ON(ret);
 759
 760         ret = btrfs_extend_item(trans, root, path, new_size);
 761         BUG_ON(ret);
 762
 763         leaf = path->nodes[0];
 764         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 765         btrfs_set_extent_refs(leaf, item, refs);
 766         /* FIXME: get real generation */
 767         btrfs_set_extent_generation(leaf, item, 0);
 768         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 769                 btrfs_set_extent_flags(leaf, item,
 770                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
 771                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
 772                 bi = (struct btrfs_tree_block_info *)(item + 1);
 773                 /* FIXME: get first key of the block */
 774                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
 775                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
 776         } else {
 777                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
 778         }
 779         btrfs_mark_buffer_dirty(leaf);
 780         return 0;
 781 }
 782 #endif
 783
 784 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 785 {
 786         u32 high_crc = ~(u32)0;
 787         u32 low_crc = ~(u32)0;
 788         __le64 lenum;
 789
 790         lenum = cpu_to_le64(root_objectid);
 791         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
 792         lenum = cpu_to_le64(owner);
 793         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 794         lenum = cpu_to_le64(offset);
 795         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 796
 797         return ((u64)high_crc << 31) ^ (u64)low_crc;
 798 }
 799
 800 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 801                                      struct btrfs_extent_data_ref *ref)
 802 {
 803         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 804                                     btrfs_extent_data_ref_objectid(leaf, ref),
 805                                     btrfs_extent_data_ref_offset(leaf, ref));
 806 }
 807
 808 static int match_extent_data_ref(struct extent_buffer *leaf,
 809                                  struct btrfs_extent_data_ref *ref,
 810                                  u64 root_objectid, u64 owner, u64 offset)
 811 {
 812         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
 813             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
 814             btrfs_extent_data_ref_offset(leaf, ref) != offset)
 815                 return 0;
 816         return 1;
 817 }
 818
 819 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 820                                            struct btrfs_root *root,
 821                                            struct btrfs_path *path,
 822                                            u64 bytenr, u64 parent,
 823                                            u64 root_objectid,
 824                                            u64 owner, u64 offset)
 825 {
 826         struct btrfs_key key;
 827         struct btrfs_extent_data_ref *ref;
 828         struct extent_buffer *leaf;
 829         u32 nritems;
 830         int ret;
 831         int recow;
 832         int err = -ENOENT;
 833
 834         key.objectid = bytenr;
 835         if (parent) {
 836                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 837                 key.offset = parent;
 838         } else {
 839                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 840                 key.offset = hash_extent_data_ref(root_objectid,
 841                                                   owner, offset);
 842         }
 843 again:
 844         recow = 0;
 845         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 846         if (ret < 0) {
 847                 err = ret;
 848                 goto fail;
 849         }
 850
 851         if (parent) {
 852                 if (!ret)
 853                         return 0;
 854 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 855                 key.type = BTRFS_EXTENT_REF_V0_KEY;
 856                 btrfs_release_path(root, path);
 857                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 858                 if (ret < 0) {
 859                         err = ret;
 860                         goto fail;
 861                 }
 862                 if (!ret)
 863                         return 0;
 864 #endif
 865                 goto fail;
 866         }
 867
 868         leaf = path->nodes[0];
 869         nritems = btrfs_header_nritems(leaf);
 870         while (1) {
 871                 if (path->slots[0] >= nritems) {
 872                         ret = btrfs_next_leaf(root, path);
 873                         if (ret < 0)
 874                                 err = ret;
 875                         if (ret)
 876                                 goto fail;
 877
 878                         leaf = path->nodes[0];
 879                         nritems = btrfs_header_nritems(leaf);
 880                         recow = 1;
 881                 }
 882
 883                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 884                 if (key.objectid != bytenr ||
 885                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
 886                         goto fail;
 887
 888                 ref = btrfs_item_ptr(leaf, path->slots[0],
 889                                      struct btrfs_extent_data_ref);
 890
 891                 if (match_extent_data_ref(leaf, ref, root_objectid,
 892                                           owner, offset)) {
 893                         if (recow) {
 894                                 btrfs_release_path(root, path);
 895                                 goto again;
 896                         }
 897                         err = 0;
 898                         break;
 899                 }
 900                 path->slots[0]++;
 901         }
 902 fail:
 903         return err;
 904 }
 905
 906 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
 907                                            struct btrfs_root *root,
 908                                            struct btrfs_path *path,
 909                                            u64 bytenr, u64 parent,
 910                                            u64 root_objectid, u64 owner,
 911                                            u64 offset, int refs_to_add)
 912 {
 913         struct btrfs_key key;
 914         struct extent_buffer *leaf;
 915         u32 size;
 916         u32 num_refs;
 917         int ret;
 918
 919         key.objectid = bytenr;
 920         if (parent) {
 921                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 922                 key.offset = parent;
 923                 size = sizeof(struct btrfs_shared_data_ref);
 924         } else {
 925                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 926                 key.offset = hash_extent_data_ref(root_objectid,
 927                                                   owner, offset);
 928                 size = sizeof(struct btrfs_extent_data_ref);
 929         }
 930
 931         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
 932         if (ret && ret != -EEXIST)
 933                 goto fail;
 934
 935         leaf = path->nodes[0];
 936         if (parent) {
 937                 struct btrfs_shared_data_ref *ref;
 938                 ref = btrfs_item_ptr(leaf, path->slots[0],
 939                                      struct btrfs_shared_data_ref);
 940                 if (ret == 0) {
 941                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
 942                 } else {
 943                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
 944                         num_refs += refs_to_add;
 945                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
 946                 }
 947         } else {
 948                 struct btrfs_extent_data_ref *ref;
 949                 while (ret == -EEXIST) {
 950                         ref = btrfs_item_ptr(leaf, path->slots[0],
 951                                              struct btrfs_extent_data_ref);
 952                         if (match_extent_data_ref(leaf, ref, root_objectid,
 953                                                   owner, offset))
 954                                 break;
 955                         btrfs_release_path(root, path);
 956                         key.offset++;
 957                         ret = btrfs_insert_empty_item(trans, root, path, &key,
 958                                                       size);
 959                         if (ret && ret != -EEXIST)
 960                                 goto fail;
 961
 962                         leaf = path->nodes[0];
 963                 }
 964                 ref = btrfs_item_ptr(leaf, path->slots[0],
 965                                      struct btrfs_extent_data_ref);
 966                 if (ret == 0) {
 967                         btrfs_set_extent_data_ref_root(leaf, ref,
 968                                                        root_objectid);
 969                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
 970                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
 971                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
 972                 } else {
 973                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
 974                         num_refs += refs_to_add;
 975                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
 976                 }
 977         }
 978         btrfs_mark_buffer_dirty(leaf);
 979         ret = 0;
 980 fail:
 981         btrfs_release_path(root, path);
 982         return ret;
 983 }
 984
 985 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
 986                                            struct btrfs_root *root,
 987                                            struct btrfs_path *path,
 988                                            int refs_to_drop)
 989 {
 990         struct btrfs_key key;
 991         struct btrfs_extent_data_ref *ref1 = NULL;
 992         struct btrfs_shared_data_ref *ref2 = NULL;
 993         struct extent_buffer *leaf;
 994         u32 num_refs = 0;
 995         int ret = 0;
 996
 997         leaf = path->nodes[0];
 998         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 999
1000         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1001                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1002                                       struct btrfs_extent_data_ref);
1003                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1004         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1005                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1006                                       struct btrfs_shared_data_ref);
1007                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1008 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1009         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1010                 struct btrfs_extent_ref_v0 *ref0;
1011                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1012                                       struct btrfs_extent_ref_v0);
1013                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1014 #endif
1015         } else {
1016                 BUG();
1017         }
1018
1019         BUG_ON(num_refs < refs_to_drop);
1020         num_refs -= refs_to_drop;
1021
1022         if (num_refs == 0) {
1023                 ret = btrfs_del_item(trans, root, path);
1024         } else {
1025                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1026                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1027                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1028                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1029 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1030                 else {
1031                         struct btrfs_extent_ref_v0 *ref0;
1032                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1033                                         struct btrfs_extent_ref_v0);
1034                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1035                 }
1036 #endif
1037                 btrfs_mark_buffer_dirty(leaf);
1038         }
1039         return ret;
1040 }
1041
1042 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1043                                           struct btrfs_path *path,
1044                                           struct btrfs_extent_inline_ref *iref)
1045 {
1046         struct btrfs_key key;
1047         struct extent_buffer *leaf;
1048         struct btrfs_extent_data_ref *ref1;
1049         struct btrfs_shared_data_ref *ref2;
1050         u32 num_refs = 0;
1051
1052         leaf = path->nodes[0];
1053         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1054         if (iref) {
1055                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1056                     BTRFS_EXTENT_DATA_REF_KEY) {
1057                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1058                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1059                 } else {
1060                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1061                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1062                 }
1063         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1064                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1065                                       struct btrfs_extent_data_ref);
1066                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1067         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1068                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1069                                       struct btrfs_shared_data_ref);
1070                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1071 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1072         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1073                 struct btrfs_extent_ref_v0 *ref0;
1074                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1075                                       struct btrfs_extent_ref_v0);
1076                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1077 #endif
1078         } else {
1079                 WARN_ON(1);
1080         }
1081         return num_refs;
1082 }
1083
1084 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1085                                           struct btrfs_root *root,
1086                                           struct btrfs_path *path,
1087                                           u64 bytenr, u64 parent,
1088                                           u64 root_objectid)
1089 {
1090         struct btrfs_key key;
1091         int ret;
1092
1093         key.objectid = bytenr;
1094         if (parent) {
1095                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1096                 key.offset = parent;
1097         } else {
1098                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1099                 key.offset = root_objectid;
1100         }
1101
1102         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1103         if (ret > 0)
1104                 ret = -ENOENT;
1105 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1106         if (ret == -ENOENT && parent) {
1107                 btrfs_release_path(root, path);
1108                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1109                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1110                 if (ret > 0)
1111                         ret = -ENOENT;
1112         }
1113 #endif
1114         return ret;
1115 }
1116
1117 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1118                                           struct btrfs_root *root,
1119                                           struct btrfs_path *path,
1120                                           u64 bytenr, u64 parent,
1121                                           u64 root_objectid)
1122 {
1123         struct btrfs_key key;
1124         int ret;
1125
1126         key.objectid = bytenr;
1127         if (parent) {
1128                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1129                 key.offset = parent;
1130         } else {
1131                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1132                 key.offset = root_objectid;
1133         }
1134
1135         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1136         btrfs_release_path(root, path);
1137         return ret;
1138 }
1139
1140 static inline int extent_ref_type(u64 parent, u64 owner)
1141 {
1142         int type;
1143         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1144                 if (parent > 0)
1145                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1146                 else
1147                         type = BTRFS_TREE_BLOCK_REF_KEY;
1148         } else {
1149                 if (parent > 0)
1150                         type = BTRFS_SHARED_DATA_REF_KEY;
1151                 else
1152                         type = BTRFS_EXTENT_DATA_REF_KEY;
1153         }
1154         return type;
1155 }
1156
1157 static int find_next_key(struct btrfs_path *path, int level,
1158                          struct btrfs_key *key)
1159
1160 {
1161         for (; level < BTRFS_MAX_LEVEL; level++) {
1162                 if (!path->nodes[level])
1163                         break;
1164                 if (path->slots[level] + 1 >=
1165                     btrfs_header_nritems(path->nodes[level]))
1166                         continue;
1167                 if (level == 0)
1168                         btrfs_item_key_to_cpu(path->nodes[level], key,
1169                                               path->slots[level] + 1);
1170                 else
1171                         btrfs_node_key_to_cpu(path->nodes[level], key,
1172                                               path->slots[level] + 1);
1173                 return 0;
1174         }
1175         return 1;
1176 }
1177
1178 /*
1179  * look for inline back ref. if back ref is found, *ref_ret is set
1180  * to the address of inline back ref, and 0 is returned.
1181  *
1182  * if back ref isn't found, *ref_ret is set to the address where it
1183  * should be inserted, and -ENOENT is returned.
1184  *
1185  * if insert is true and there are too many inline back refs, the path
1186  * points to the extent item, and -EAGAIN is returned.
1187  *
1188  * NOTE: inline back refs are ordered in the same way that back ref
1189  *       items in the tree are ordered.
1190  */
1191 static noinline_for_stack
1192 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1193                                  struct btrfs_root *root,
1194                                  struct btrfs_path *path,
1195                                  struct btrfs_extent_inline_ref **ref_ret,
1196                                  u64 bytenr, u64 num_bytes,
1197                                  u64 parent, u64 root_objectid,
1198                                  u64 owner, u64 offset, int insert)
1199 {
1200         struct btrfs_key key;
1201         struct extent_buffer *leaf;
1202         struct btrfs_extent_item *ei;
1203         struct btrfs_extent_inline_ref *iref;
1204         u64 flags;
1205         u64 item_size;
1206         unsigned long ptr;
1207         unsigned long end;
1208         int extra_size;
1209         int type;
1210         int want;
1211         int ret;
1212         int err = 0;
1213
1214         key.objectid = bytenr;
1215         key.type = BTRFS_EXTENT_ITEM_KEY;
1216         key.offset = num_bytes;
1217
1218         want = extent_ref_type(parent, owner);
1219         if (insert) {
1220                 extra_size = btrfs_extent_inline_ref_size(want);
1221                 path->keep_locks = 1;
1222         } else
1223                 extra_size = -1;
1224         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1225         if (ret < 0) {
1226                 err = ret;
1227                 goto out;
1228         }
1229         BUG_ON(ret);
1230
1231         leaf = path->nodes[0];
1232         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1233 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1234         if (item_size < sizeof(*ei)) {
1235                 if (!insert) {
1236                         err = -ENOENT;
1237                         goto out;
1238                 }
1239                 ret = convert_extent_item_v0(trans, root, path, owner,
1240                                              extra_size);
1241                 if (ret < 0) {
1242                         err = ret;
1243                         goto out;
1244                 }
1245                 leaf = path->nodes[0];
1246                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1247         }
1248 #endif
1249         BUG_ON(item_size < sizeof(*ei));
1250
1251         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1252         flags = btrfs_extent_flags(leaf, ei);
1253
1254         ptr = (unsigned long)(ei + 1);
1255         end = (unsigned long)ei + item_size;
1256
1257         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1258                 ptr += sizeof(struct btrfs_tree_block_info);
1259                 BUG_ON(ptr > end);
1260         } else {
1261                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1262         }
1263
1264         err = -ENOENT;
1265         while (1) {
1266                 if (ptr >= end) {
1267                         WARN_ON(ptr > end);
1268                         break;
1269                 }
1270                 iref = (struct btrfs_extent_inline_ref *)ptr;
1271                 type = btrfs_extent_inline_ref_type(leaf, iref);
1272                 if (want < type)
1273                         break;
1274                 if (want > type) {
1275                         ptr += btrfs_extent_inline_ref_size(type);
1276                         continue;
1277                 }
1278
1279                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1280                         struct btrfs_extent_data_ref *dref;
1281                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1282                         if (match_extent_data_ref(leaf, dref, root_objectid,
1283                                                   owner, offset)) {
1284                                 err = 0;
1285                                 break;
1286                         }
1287                         if (hash_extent_data_ref_item(leaf, dref) <
1288                             hash_extent_data_ref(root_objectid, owner, offset))
1289                                 break;
1290                 } else {
1291                         u64 ref_offset;
1292                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1293                         if (parent > 0) {
1294                                 if (parent == ref_offset) {
1295                                         err = 0;
1296                                         break;
1297                                 }
1298                                 if (ref_offset < parent)
1299                                         break;
1300                         } else {
1301                                 if (root_objectid == ref_offset) {
1302                                         err = 0;
1303                                         break;
1304                                 }
1305                                 if (ref_offset < root_objectid)
1306                                         break;
1307                         }
1308                 }
1309                 ptr += btrfs_extent_inline_ref_size(type);
1310         }
1311         if (err == -ENOENT && insert) {
1312                 if (item_size + extra_size >=
1313                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1314                         err = -EAGAIN;
1315                         goto out;
1316                 }
1317                 /*
1318                  * To add new inline back ref, we have to make sure
1319                  * there is no corresponding back ref item.
1320                  * For simplicity, we just do not add new inline back
1321                  * ref if there is any kind of item for this block
1322                  */
1323                 if (find_next_key(path, 0, &key) == 0 &&
1324                     key.objectid == bytenr &&
1325                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1326                         err = -EAGAIN;
1327                         goto out;
1328                 }
1329         }
1330         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1331 out:
1332         if (insert) {
1333                 path->keep_locks = 0;
1334                 btrfs_unlock_up_safe(path, 1);
1335         }
1336         return err;
1337 }
1338
1339 /*
1340  * helper to add new inline back ref
1341  */
1342 static noinline_for_stack
1343 int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1344                                 struct btrfs_root *root,
1345                                 struct btrfs_path *path,
1346                                 struct btrfs_extent_inline_ref *iref,
1347                                 u64 parent, u64 root_objectid,
1348                                 u64 owner, u64 offset, int refs_to_add,
1349                                 struct btrfs_delayed_extent_op *extent_op)
1350 {
1351         struct extent_buffer *leaf;
1352         struct btrfs_extent_item *ei;
1353         unsigned long ptr;
1354         unsigned long end;
1355         unsigned long item_offset;
1356         u64 refs;
1357         int size;
1358         int type;
1359         int ret;
1360
1361         leaf = path->nodes[0];
1362         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1363         item_offset = (unsigned long)iref - (unsigned long)ei;
1364
1365         type = extent_ref_type(parent, owner);
1366         size = btrfs_extent_inline_ref_size(type);
1367
1368         ret = btrfs_extend_item(trans, root, path, size);
1369         BUG_ON(ret);
1370
1371         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1372         refs = btrfs_extent_refs(leaf, ei);
1373         refs += refs_to_add;
1374         btrfs_set_extent_refs(leaf, ei, refs);
1375         if (extent_op)
1376                 __run_delayed_extent_op(extent_op, leaf, ei);
1377
1378         ptr = (unsigned long)ei + item_offset;
1379         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1380         if (ptr < end - size)
1381                 memmove_extent_buffer(leaf, ptr + size, ptr,
1382                                       end - size - ptr);
1383
1384         iref = (struct btrfs_extent_inline_ref *)ptr;
1385         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1386         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1387                 struct btrfs_extent_data_ref *dref;
1388                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1389                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1390                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1391                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1392                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1393         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1394                 struct btrfs_shared_data_ref *sref;
1395                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1396                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1397                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1398         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1399                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1400         } else {
1401                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1402         }
1403         btrfs_mark_buffer_dirty(leaf);
1404         return 0;
1405 }
1406
1407 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1408                                  struct btrfs_root *root,
1409                                  struct btrfs_path *path,
1410                                  struct btrfs_extent_inline_ref **ref_ret,
1411                                  u64 bytenr, u64 num_bytes, u64 parent,
1412                                  u64 root_objectid, u64 owner, u64 offset)
1413 {
1414         int ret;
1415
1416         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1417                                            bytenr, num_bytes, parent,
1418                                            root_objectid, owner, offset, 0);
1419         if (ret != -ENOENT)
1420                 return ret;
1421
1422         btrfs_release_path(root, path);
1423         *ref_ret = NULL;
1424
1425         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1426                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1427                                             root_objectid);
1428         } else {
1429                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1430                                              root_objectid, owner, offset);
1431         }
1432         return ret;
1433 }
1434
1435 /*
1436  * helper to update/remove inline back ref
1437  */
1438 static noinline_for_stack
1439 int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1440                                  struct btrfs_root *root,
1441                                  struct btrfs_path *path,
1442                                  struct btrfs_extent_inline_ref *iref,
1443                                  int refs_to_mod,
1444                                  struct btrfs_delayed_extent_op *extent_op)
1445 {
1446         struct extent_buffer *leaf;
1447         struct btrfs_extent_item *ei;
1448         struct btrfs_extent_data_ref *dref = NULL;
1449         struct btrfs_shared_data_ref *sref = NULL;
1450         unsigned long ptr;
1451         unsigned long end;
1452         u32 item_size;
1453         int size;
1454         int type;
1455         int ret;
1456         u64 refs;
1457
1458         leaf = path->nodes[0];
1459         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1460         refs = btrfs_extent_refs(leaf, ei);
1461         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1462         refs += refs_to_mod;
1463         btrfs_set_extent_refs(leaf, ei, refs);
1464         if (extent_op)
1465                 __run_delayed_extent_op(extent_op, leaf, ei);
1466
1467         type = btrfs_extent_inline_ref_type(leaf, iref);
1468
1469         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1470                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1471                 refs = btrfs_extent_data_ref_count(leaf, dref);
1472         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1473                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1474                 refs = btrfs_shared_data_ref_count(leaf, sref);
1475         } else {
1476                 refs = 1;
1477                 BUG_ON(refs_to_mod != -1);
1478         }
1479
1480         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1481         refs += refs_to_mod;
1482
1483         if (refs > 0) {
1484                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1485                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1486                 else
1487                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1488         } else {
1489                 size =  btrfs_extent_inline_ref_size(type);
1490                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1491                 ptr = (unsigned long)iref;
1492                 end = (unsigned long)ei + item_size;
1493                 if (ptr + size < end)
1494                         memmove_extent_buffer(leaf, ptr, ptr + size,
1495                                               end - ptr - size);
1496                 item_size -= size;
1497                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1498                 BUG_ON(ret);
1499         }
1500         btrfs_mark_buffer_dirty(leaf);
1501         return 0;
1502 }
1503
1504 static noinline_for_stack
1505 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1506                                  struct btrfs_root *root,
1507                                  struct btrfs_path *path,
1508                                  u64 bytenr, u64 num_bytes, u64 parent,
1509                                  u64 root_objectid, u64 owner,
1510                                  u64 offset, int refs_to_add,
1511                                  struct btrfs_delayed_extent_op *extent_op)
1512 {
1513         struct btrfs_extent_inline_ref *iref;
1514         int ret;
1515
1516         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1517                                            bytenr, num_bytes, parent,
1518                                            root_objectid, owner, offset, 1);
1519         if (ret == 0) {
1520                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1521                 ret = update_inline_extent_backref(trans, root, path, iref,
1522                                                    refs_to_add, extent_op);
1523         } else if (ret == -ENOENT) {
1524                 ret = setup_inline_extent_backref(trans, root, path, iref,
1525                                                   parent, root_objectid,
1526                                                   owner, offset, refs_to_add,
1527                                                   extent_op);
1528         }
1529         return ret;
1530 }
1531
1532 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1533                                  struct btrfs_root *root,
1534                                  struct btrfs_path *path,
1535                                  u64 bytenr, u64 parent, u64 root_objectid,
1536                                  u64 owner, u64 offset, int refs_to_add)
1537 {
1538         int ret;
1539         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1540                 BUG_ON(refs_to_add != 1);
1541                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1542                                             parent, root_objectid);
1543         } else {
1544                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1545                                              parent, root_objectid,
1546                                              owner, offset, refs_to_add);
1547         }
1548         return ret;
1549 }
1550
1551 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1552                                  struct btrfs_root *root,
1553                                  struct btrfs_path *path,
1554                                  struct btrfs_extent_inline_ref *iref,
1555                                  int refs_to_drop, int is_data)
1556 {
1557         int ret;
1558
1559         BUG_ON(!is_data && refs_to_drop != 1);
1560         if (iref) {
1561                 ret = update_inline_extent_backref(trans, root, path, iref,
1562                                                    -refs_to_drop, NULL);
1563         } else if (is_data) {
1564                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1565         } else {
1566                 ret = btrfs_del_item(trans, root, path);
1567         }
1568         return ret;
1569 }
1570
1571 static void btrfs_issue_discard(struct block_device *bdev,
1572                                 u64 start, u64 len)
1573 {
1574         blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL,
1575                              DISCARD_FL_BARRIER);
1576 }
1577
1578 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1579                                 u64 num_bytes)
1580 {
1581         int ret;
1582         u64 map_length = num_bytes;
1583         struct btrfs_multi_bio *multi = NULL;
1584
1585         if (!btrfs_test_opt(root, DISCARD))
1586                 return 0;
1587
1588         /* Tell the block device(s) that the sectors can be discarded */
1589         ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
1590                               bytenr, &map_length, &multi, 0);
1591         if (!ret) {
1592                 struct btrfs_bio_stripe *stripe = multi->stripes;
1593                 int i;
1594
1595                 if (map_length > num_bytes)
1596                         map_length = num_bytes;
1597
1598                 for (i = 0; i < multi->num_stripes; i++, stripe++) {
1599                         btrfs_issue_discard(stripe->dev->bdev,
1600                                             stripe->physical,
1601                                             map_length);
1602                 }
1603                 kfree(multi);
1604         }
1605
1606         return ret;
1607 }
1608
1609 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1610                          struct btrfs_root *root,
1611                          u64 bytenr, u64 num_bytes, u64 parent,
1612                          u64 root_objectid, u64 owner, u64 offset)
1613 {
1614         int ret;
1615         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1616                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1617
1618         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1619                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
1620                                         parent, root_objectid, (int)owner,
1621                                         BTRFS_ADD_DELAYED_REF, NULL);
1622         } else {
1623                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
1624                                         parent, root_objectid, owner, offset,
1625                                         BTRFS_ADD_DELAYED_REF, NULL);
1626         }
1627         return ret;
1628 }
1629
1630 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1631                                   struct btrfs_root *root,
1632                                   u64 bytenr, u64 num_bytes,
1633                                   u64 parent, u64 root_objectid,
1634                                   u64 owner, u64 offset, int refs_to_add,
1635                                   struct btrfs_delayed_extent_op *extent_op)
1636 {
1637         struct btrfs_path *path;
1638         struct extent_buffer *leaf;
1639         struct btrfs_extent_item *item;
1640         u64 refs;
1641         int ret;
1642         int err = 0;
1643
1644         path = btrfs_alloc_path();
1645         if (!path)
1646                 return -ENOMEM;
1647
1648         path->reada = 1;
1649         path->leave_spinning = 1;
1650         /* this will setup the path even if it fails to insert the back ref */
1651         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1652                                            path, bytenr, num_bytes, parent,
1653                                            root_objectid, owner, offset,
1654                                            refs_to_add, extent_op);
1655         if (ret == 0)
1656                 goto out;
1657
1658         if (ret != -EAGAIN) {
1659                 err = ret;
1660                 goto out;
1661         }
1662
1663         leaf = path->nodes[0];
1664         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1665         refs = btrfs_extent_refs(leaf, item);
1666         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1667         if (extent_op)
1668                 __run_delayed_extent_op(extent_op, leaf, item);
1669
1670         btrfs_mark_buffer_dirty(leaf);
1671         btrfs_release_path(root->fs_info->extent_root, path);
1672
1673         path->reada = 1;
1674         path->leave_spinning = 1;
1675
1676         /* now insert the actual backref */
1677         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1678                                     path, bytenr, parent, root_objectid,
1679                                     owner, offset, refs_to_add);
1680         BUG_ON(ret);
1681 out:
1682         btrfs_free_path(path);
1683         return err;
1684 }
1685
1686 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1687                                 struct btrfs_root *root,
1688                                 struct btrfs_delayed_ref_node *node,
1689                                 struct btrfs_delayed_extent_op *extent_op,
1690                                 int insert_reserved)
1691 {
1692         int ret = 0;
1693         struct btrfs_delayed_data_ref *ref;
1694         struct btrfs_key ins;
1695         u64 parent = 0;
1696         u64 ref_root = 0;
1697         u64 flags = 0;
1698
1699         ins.objectid = node->bytenr;
1700         ins.offset = node->num_bytes;
1701         ins.type = BTRFS_EXTENT_ITEM_KEY;
1702
1703         ref = btrfs_delayed_node_to_data_ref(node);
1704         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1705                 parent = ref->parent;
1706         else
1707                 ref_root = ref->root;
1708
1709         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1710                 if (extent_op) {
1711                         BUG_ON(extent_op->update_key);
1712                         flags |= extent_op->flags_to_set;
1713                 }
1714                 ret = alloc_reserved_file_extent(trans, root,
1715                                                  parent, ref_root, flags,
1716                                                  ref->objectid, ref->offset,
1717                                                  &ins, node->ref_mod);
1718         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1719                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1720                                              node->num_bytes, parent,
1721                                              ref_root, ref->objectid,
1722                                              ref->offset, node->ref_mod,
1723                                              extent_op);
1724         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1725                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1726                                           node->num_bytes, parent,
1727                                           ref_root, ref->objectid,
1728                                           ref->offset, node->ref_mod,
1729                                           extent_op);
1730         } else {
1731                 BUG();
1732         }
1733         return ret;
1734 }
1735
1736 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1737                                     struct extent_buffer *leaf,
1738                                     struct btrfs_extent_item *ei)
1739 {
1740         u64 flags = btrfs_extent_flags(leaf, ei);
1741         if (extent_op->update_flags) {
1742                 flags |= extent_op->flags_to_set;
1743                 btrfs_set_extent_flags(leaf, ei, flags);
1744         }
1745
1746         if (extent_op->update_key) {
1747                 struct btrfs_tree_block_info *bi;
1748                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1749                 bi = (struct btrfs_tree_block_info *)(ei + 1);
1750                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1751         }
1752 }
1753
1754 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1755                                  struct btrfs_root *root,
1756                                  struct btrfs_delayed_ref_node *node,
1757                                  struct btrfs_delayed_extent_op *extent_op)
1758 {
1759         struct btrfs_key key;
1760         struct btrfs_path *path;
1761         struct btrfs_extent_item *ei;
1762         struct extent_buffer *leaf;
1763         u32 item_size;
1764         int ret;
1765         int err = 0;
1766
1767         path = btrfs_alloc_path();
1768         if (!path)
1769                 return -ENOMEM;
1770
1771         key.objectid = node->bytenr;
1772         key.type = BTRFS_EXTENT_ITEM_KEY;
1773         key.offset = node->num_bytes;
1774
1775         path->reada = 1;
1776         path->leave_spinning = 1;
1777         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
1778                                 path, 0, 1);
1779         if (ret < 0) {
1780                 err = ret;
1781                 goto out;
1782         }
1783         if (ret > 0) {
1784                 err = -EIO;
1785                 goto out;
1786         }
1787
1788         leaf = path->nodes[0];
1789         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1790 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1791         if (item_size < sizeof(*ei)) {
1792                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
1793                                              path, (u64)-1, 0);
1794                 if (ret < 0) {
1795                         err = ret;
1796                         goto out;
1797                 }
1798                 leaf = path->nodes[0];
1799                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1800         }
1801 #endif
1802         BUG_ON(item_size < sizeof(*ei));
1803         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1804         __run_delayed_extent_op(extent_op, leaf, ei);
1805
1806         btrfs_mark_buffer_dirty(leaf);
1807 out:
1808         btrfs_free_path(path);
1809         return err;
1810 }
1811
1812 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
1813                                 struct btrfs_root *root,
1814                                 struct btrfs_delayed_ref_node *node,
1815                                 struct btrfs_delayed_extent_op *extent_op,
1816                                 int insert_reserved)
1817 {
1818         int ret = 0;
1819         struct btrfs_delayed_tree_ref *ref;
1820         struct btrfs_key ins;
1821         u64 parent = 0;
1822         u64 ref_root = 0;
1823
1824         ins.objectid = node->bytenr;
1825         ins.offset = node->num_bytes;
1826         ins.type = BTRFS_EXTENT_ITEM_KEY;
1827
1828         ref = btrfs_delayed_node_to_tree_ref(node);
1829         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1830                 parent = ref->parent;
1831         else
1832                 ref_root = ref->root;
1833
1834         BUG_ON(node->ref_mod != 1);
1835         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1836                 BUG_ON(!extent_op || !extent_op->update_flags ||
1837                        !extent_op->update_key);
1838                 ret = alloc_reserved_tree_block(trans, root,
1839                                                 parent, ref_root,
1840                                                 extent_op->flags_to_set,
1841                                                 &extent_op->key,
1842                                                 ref->level, &ins);
1843         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1844                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1845                                              node->num_bytes, parent, ref_root,
1846                                              ref->level, 0, 1, extent_op);
1847         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1848                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1849                                           node->num_bytes, parent, ref_root,
1850                                           ref->level, 0, 1, extent_op);
1851         } else {
1852                 BUG();
1853         }
1854         return ret;
1855 }
1856
1857
1858 /* helper function to actually process a single delayed ref entry */
1859 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
1860                                struct btrfs_root *root,
1861                                struct btrfs_delayed_ref_node *node,
1862                                struct btrfs_delayed_extent_op *extent_op,
1863                                int insert_reserved)
1864 {
1865         int ret;
1866         if (btrfs_delayed_ref_is_head(node)) {
1867                 struct btrfs_delayed_ref_head *head;
1868                 /*
1869                  * we've hit the end of the chain and we were supposed
1870                  * to insert this extent into the tree.  But, it got
1871                  * deleted before we ever needed to insert it, so all
1872                  * we have to do is clean up the accounting
1873                  */
1874                 BUG_ON(extent_op);
1875                 head = btrfs_delayed_node_to_head(node);
1876                 if (insert_reserved) {
1877                         int mark_free = 0;
1878                         struct extent_buffer *must_clean = NULL;
1879
1880                         ret = pin_down_bytes(trans, root, NULL,
1881                                              node->bytenr, node->num_bytes,
1882                                              head->is_data, 1, &must_clean);
1883                         if (ret > 0)
1884                                 mark_free = 1;
1885
1886                         if (must_clean) {
1887                                 clean_tree_block(NULL, root, must_clean);
1888                                 btrfs_tree_unlock(must_clean);
1889                                 free_extent_buffer(must_clean);
1890                         }
1891                         if (head->is_data) {
1892                                 ret = btrfs_del_csums(trans, root,
1893                                                       node->bytenr,
1894                                                       node->num_bytes);
1895                                 BUG_ON(ret);
1896                         }
1897                         if (mark_free) {
1898                                 ret = btrfs_free_reserved_extent(root,
1899                                                         node->bytenr,
1900                                                         node->num_bytes);
1901                                 BUG_ON(ret);
1902                         }
1903                 }
1904                 mutex_unlock(&head->mutex);
1905                 return 0;
1906         }
1907
1908         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
1909             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1910                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
1911                                            insert_reserved);
1912         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
1913                  node->type == BTRFS_SHARED_DATA_REF_KEY)
1914                 ret = run_delayed_data_ref(trans, root, node, extent_op,
1915                                            insert_reserved);
1916         else
1917                 BUG();
1918         return ret;
1919 }
1920
1921 static noinline struct btrfs_delayed_ref_node *
1922 select_delayed_ref(struct btrfs_delayed_ref_head *head)
1923 {
1924         struct rb_node *node;
1925         struct btrfs_delayed_ref_node *ref;
1926         int action = BTRFS_ADD_DELAYED_REF;
1927 again:
1928         /*
1929          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
1930          * this prevents ref count from going down to zero when
1931          * there still are pending delayed ref.
1932          */
1933         node = rb_prev(&head->node.rb_node);
1934         while (1) {
1935                 if (!node)
1936                         break;
1937                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
1938                                 rb_node);
1939                 if (ref->bytenr != head->node.bytenr)
1940                         break;
1941                 if (ref->action == action)
1942                         return ref;
1943                 node = rb_prev(node);
1944         }
1945         if (action == BTRFS_ADD_DELAYED_REF) {
1946                 action = BTRFS_DROP_DELAYED_REF;
1947                 goto again;
1948         }
1949         return NULL;
1950 }
1951
1952 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
1953                                        struct btrfs_root *root,
1954                                        struct list_head *cluster)
1955 {
1956         struct btrfs_delayed_ref_root *delayed_refs;
1957         struct btrfs_delayed_ref_node *ref;
1958         struct btrfs_delayed_ref_head *locked_ref = NULL;
1959         struct btrfs_delayed_extent_op *extent_op;
1960         int ret;
1961         int count = 0;
1962         int must_insert_reserved = 0;
1963
1964         delayed_refs = &trans->transaction->delayed_refs;
1965         while (1) {
1966                 if (!locked_ref) {
1967                         /* pick a new head ref from the cluster list */
1968                         if (list_empty(cluster))
1969                                 break;
1970
1971                         locked_ref = list_entry(cluster->next,
1972                                      struct btrfs_delayed_ref_head, cluster);
1973
1974                         /* grab the lock that says we are going to process
1975                          * all the refs for this head */
1976                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
1977
1978                         /*
1979                          * we may have dropped the spin lock to get the head
1980                          * mutex lock, and that might have given someone else
1981                          * time to free the head.  If that's true, it has been
1982                          * removed from our list and we can move on.
1983                          */
1984                         if (ret == -EAGAIN) {
1985                                 locked_ref = NULL;
1986                                 count++;
1987                                 continue;
1988                         }
1989                 }
1990
1991                 /*
1992                  * record the must insert reserved flag before we
1993                  * drop the spin lock.
1994                  */
1995                 must_insert_reserved = locked_ref->must_insert_reserved;
1996                 locked_ref->must_insert_reserved = 0;
1997
1998                 extent_op = locked_ref->extent_op;
1999                 locked_ref->extent_op = NULL;
2000
2001                 /*
2002                  * locked_ref is the head node, so we have to go one
2003                  * node back for any delayed ref updates
2004                  */
2005                 ref = select_delayed_ref(locked_ref);
2006                 if (!ref) {
2007                         /* All delayed refs have been processed, Go ahead
2008                          * and send the head node to run_one_delayed_ref,
2009                          * so that any accounting fixes can happen
2010                          */
2011                         ref = &locked_ref->node;
2012
2013                         if (extent_op && must_insert_reserved) {
2014                                 kfree(extent_op);
2015                                 extent_op = NULL;
2016                         }
2017
2018                         if (extent_op) {
2019                                 spin_unlock(&delayed_refs->lock);
2020
2021                                 ret = run_delayed_extent_op(trans, root,
2022                                                             ref, extent_op);
2023                                 BUG_ON(ret);
2024                                 kfree(extent_op);
2025
2026                                 cond_resched();
2027                                 spin_lock(&delayed_refs->lock);
2028                                 continue;
2029                         }
2030
2031                         list_del_init(&locked_ref->cluster);
2032                         locked_ref = NULL;
2033                 }
2034
2035                 ref->in_tree = 0;
2036                 rb_erase(&ref->rb_node, &delayed_refs->root);
2037                 delayed_refs->num_entries--;
2038
2039                 spin_unlock(&delayed_refs->lock);
2040
2041                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2042                                           must_insert_reserved);
2043                 BUG_ON(ret);
2044
2045                 btrfs_put_delayed_ref(ref);
2046                 kfree(extent_op);
2047                 count++;
2048
2049                 cond_resched();
2050                 spin_lock(&delayed_refs->lock);
2051         }
2052         return count;
2053 }
2054
2055 /*
2056  * this starts processing the delayed reference count updates and
2057  * extent insertions we have queued up so far.  count can be
2058  * 0, which means to process everything in the tree at the start
2059  * of the run (but not newly added entries), or it can be some target
2060  * number you'd like to process.
2061  */
2062 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2063                            struct btrfs_root *root, unsigned long count)
2064 {
2065         struct rb_node *node;
2066         struct btrfs_delayed_ref_root *delayed_refs;
2067         struct btrfs_delayed_ref_node *ref;
2068         struct list_head cluster;
2069         int ret;
2070         int run_all = count == (unsigned long)-1;
2071         int run_most = 0;
2072
2073         if (root == root->fs_info->extent_root)
2074                 root = root->fs_info->tree_root;
2075
2076         delayed_refs = &trans->transaction->delayed_refs;
2077         INIT_LIST_HEAD(&cluster);
2078 again:
2079         spin_lock(&delayed_refs->lock);
2080         if (count == 0) {
2081                 count = delayed_refs->num_entries * 2;
2082                 run_most = 1;
2083         }
2084         while (1) {
2085                 if (!(run_all || run_most) &&
2086                     delayed_refs->num_heads_ready < 64)
2087                         break;
2088
2089                 /*
2090                  * go find something we can process in the rbtree.  We start at
2091                  * the beginning of the tree, and then build a cluster
2092                  * of refs to process starting at the first one we are able to
2093                  * lock
2094                  */
2095                 ret = btrfs_find_ref_cluster(trans, &cluster,
2096                                              delayed_refs->run_delayed_start);
2097                 if (ret)
2098                         break;
2099
2100                 ret = run_clustered_refs(trans, root, &cluster);
2101                 BUG_ON(ret < 0);
2102
2103                 count -= min_t(unsigned long, ret, count);
2104
2105                 if (count == 0)
2106                         break;
2107         }
2108
2109         if (run_all) {
2110                 node = rb_first(&delayed_refs->root);
2111                 if (!node)
2112                         goto out;
2113                 count = (unsigned long)-1;
2114
2115                 while (node) {
2116                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2117                                        rb_node);
2118                         if (btrfs_delayed_ref_is_head(ref)) {
2119                                 struct btrfs_delayed_ref_head *head;
2120
2121                                 head = btrfs_delayed_node_to_head(ref);
2122                                 atomic_inc(&ref->refs);
2123
2124                                 spin_unlock(&delayed_refs->lock);
2125                                 mutex_lock(&head->mutex);
2126                                 mutex_unlock(&head->mutex);
2127
2128                                 btrfs_put_delayed_ref(ref);
2129                                 cond_resched();
2130                                 goto again;
2131                         }
2132                         node = rb_next(node);
2133                 }
2134                 spin_unlock(&delayed_refs->lock);
2135                 schedule_timeout(1);
2136                 goto again;
2137         }
2138 out:
2139         spin_unlock(&delayed_refs->lock);
2140         return 0;
2141 }
2142
2143 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2144                                 struct btrfs_root *root,
2145                                 u64 bytenr, u64 num_bytes, u64 flags,
2146                                 int is_data)
2147 {
2148         struct btrfs_delayed_extent_op *extent_op;
2149         int ret;
2150
2151         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2152         if (!extent_op)
2153                 return -ENOMEM;
2154
2155         extent_op->flags_to_set = flags;
2156         extent_op->update_flags = 1;
2157         extent_op->update_key = 0;
2158         extent_op->is_data = is_data ? 1 : 0;
2159
2160         ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
2161         if (ret)
2162                 kfree(extent_op);
2163         return ret;
2164 }
2165
2166 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2167                                       struct btrfs_root *root,
2168                                       struct btrfs_path *path,
2169                                       u64 objectid, u64 offset, u64 bytenr)
2170 {
2171         struct btrfs_delayed_ref_head *head;
2172         struct btrfs_delayed_ref_node *ref;
2173         struct btrfs_delayed_data_ref *data_ref;
2174         struct btrfs_delayed_ref_root *delayed_refs;
2175         struct rb_node *node;
2176         int ret = 0;
2177
2178         ret = -ENOENT;
2179         delayed_refs = &trans->transaction->delayed_refs;
2180         spin_lock(&delayed_refs->lock);
2181         head = btrfs_find_delayed_ref_head(trans, bytenr);
2182         if (!head)
2183                 goto out;
2184
2185         if (!mutex_trylock(&head->mutex)) {
2186                 atomic_inc(&head->node.refs);
2187                 spin_unlock(&delayed_refs->lock);
2188
2189                 btrfs_release_path(root->fs_info->extent_root, path);
2190
2191                 mutex_lock(&head->mutex);
2192                 mutex_unlock(&head->mutex);
2193                 btrfs_put_delayed_ref(&head->node);
2194                 return -EAGAIN;
2195         }
2196
2197         node = rb_prev(&head->node.rb_node);
2198         if (!node)
2199                 goto out_unlock;
2200
2201         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2202
2203         if (ref->bytenr != bytenr)
2204                 goto out_unlock;
2205
2206         ret = 1;
2207         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2208                 goto out_unlock;
2209
2210         data_ref = btrfs_delayed_node_to_data_ref(ref);
2211
2212         node = rb_prev(node);
2213         if (node) {
2214                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2215                 if (ref->bytenr == bytenr)
2216                         goto out_unlock;
2217         }
2218
2219         if (data_ref->root != root->root_key.objectid ||
2220             data_ref->objectid != objectid || data_ref->offset != offset)
2221                 goto out_unlock;
2222
2223         ret = 0;
2224 out_unlock:
2225         mutex_unlock(&head->mutex);
2226 out:
2227         spin_unlock(&delayed_refs->lock);
2228         return ret;
2229 }
2230
2231 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2232                                         struct btrfs_root *root,
2233                                         struct btrfs_path *path,
2234                                         u64 objectid, u64 offset, u64 bytenr)
2235 {
2236         struct btrfs_root *extent_root = root->fs_info->extent_root;
2237         struct extent_buffer *leaf;
2238         struct btrfs_extent_data_ref *ref;
2239         struct btrfs_extent_inline_ref *iref;
2240         struct btrfs_extent_item *ei;
2241         struct btrfs_key key;
2242         u32 item_size;
2243         int ret;
2244
2245         key.objectid = bytenr;
2246         key.offset = (u64)-1;
2247         key.type = BTRFS_EXTENT_ITEM_KEY;
2248
2249         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2250         if (ret < 0)
2251                 goto out;
2252         BUG_ON(ret == 0);
2253
2254         ret = -ENOENT;
2255         if (path->slots[0] == 0)
2256                 goto out;
2257
2258         path->slots[0]--;
2259         leaf = path->nodes[0];
2260         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2261
2262         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2263                 goto out;
2264
2265         ret = 1;
2266         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2267 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2268         if (item_size < sizeof(*ei)) {
2269                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2270                 goto out;
2271         }
2272 #endif
2273         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2274
2275         if (item_size != sizeof(*ei) +
2276             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2277                 goto out;
2278
2279         if (btrfs_extent_generation(leaf, ei) <=
2280             btrfs_root_last_snapshot(&root->root_item))
2281                 goto out;
2282
2283         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2284         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2285             BTRFS_EXTENT_DATA_REF_KEY)
2286                 goto out;
2287
2288         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2289         if (btrfs_extent_refs(leaf, ei) !=
2290             btrfs_extent_data_ref_count(leaf, ref) ||
2291             btrfs_extent_data_ref_root(leaf, ref) !=
2292             root->root_key.objectid ||
2293             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2294             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2295                 goto out;
2296
2297         ret = 0;
2298 out:
2299         return ret;
2300 }
2301
2302 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2303                           struct btrfs_root *root,
2304                           u64 objectid, u64 offset, u64 bytenr)
2305 {
2306         struct btrfs_path *path;
2307         int ret;
2308         int ret2;
2309
2310         path = btrfs_alloc_path();
2311         if (!path)
2312                 return -ENOENT;
2313
2314         do {
2315                 ret = check_committed_ref(trans, root, path, objectid,
2316                                           offset, bytenr);
2317                 if (ret && ret != -ENOENT)
2318                         goto out;
2319
2320                 ret2 = check_delayed_ref(trans, root, path, objectid,
2321                                          offset, bytenr);
2322         } while (ret2 == -EAGAIN);
2323
2324         if (ret2 && ret2 != -ENOENT) {
2325                 ret = ret2;
2326                 goto out;
2327         }
2328
2329         if (ret != -ENOENT || ret2 != -ENOENT)
2330                 ret = 0;
2331 out:
2332         btrfs_free_path(path);
2333         return ret;
2334 }
2335
2336 #if 0
2337 int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2338                     struct extent_buffer *buf, u32 nr_extents)
2339 {
2340         struct btrfs_key key;
2341         struct btrfs_file_extent_item *fi;
2342         u64 root_gen;
2343         u32 nritems;
2344         int i;
2345         int level;
2346         int ret = 0;
2347         int shared = 0;
2348
2349         if (!root->ref_cows)
2350                 return 0;
2351
2352         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2353                 shared = 0;
2354                 root_gen = root->root_key.offset;
2355         } else {
2356                 shared = 1;
2357                 root_gen = trans->transid - 1;
2358         }
2359
2360         level = btrfs_header_level(buf);
2361         nritems = btrfs_header_nritems(buf);
2362
2363         if (level == 0) {
2364                 struct btrfs_leaf_ref *ref;
2365                 struct btrfs_extent_info *info;
2366
2367                 ref = btrfs_alloc_leaf_ref(root, nr_extents);
2368                 if (!ref) {
2369                         ret = -ENOMEM;
2370                         goto out;
2371                 }
2372
2373                 ref->root_gen = root_gen;
2374                 ref->bytenr = buf->start;
2375                 ref->owner = btrfs_header_owner(buf);
2376                 ref->generation = btrfs_header_generation(buf);
2377                 ref->nritems = nr_extents;
2378                 info = ref->extents;
2379
2380                 for (i = 0; nr_extents > 0 && i < nritems; i++) {
2381                         u64 disk_bytenr;
2382                         btrfs_item_key_to_cpu(buf, &key, i);
2383                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2384                                 continue;
2385                         fi = btrfs_item_ptr(buf, i,
2386                                             struct btrfs_file_extent_item);
2387                         if (btrfs_file_extent_type(buf, fi) ==
2388                             BTRFS_FILE_EXTENT_INLINE)
2389                                 continue;
2390                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2391                         if (disk_bytenr == 0)
2392                                 continue;
2393
2394                         info->bytenr = disk_bytenr;
2395                         info->num_bytes =
2396                                 btrfs_file_extent_disk_num_bytes(buf, fi);
2397                         info->objectid = key.objectid;
2398                         info->offset = key.offset;
2399                         info++;
2400                 }
2401
2402                 ret = btrfs_add_leaf_ref(root, ref, shared);
2403                 if (ret == -EEXIST && shared) {
2404                         struct btrfs_leaf_ref *old;
2405                         old = btrfs_lookup_leaf_ref(root, ref->bytenr);
2406                         BUG_ON(!old);
2407                         btrfs_remove_leaf_ref(root, old);
2408                         btrfs_free_leaf_ref(root, old);
2409                         ret = btrfs_add_leaf_ref(root, ref, shared);
2410                 }
2411                 WARN_ON(ret);
2412                 btrfs_free_leaf_ref(root, ref);
2413         }
2414 out:
2415         return ret;
2416 }
2417
2418 /* when a block goes through cow, we update the reference counts of
2419  * everything that block points to.  The internal pointers of the block
2420  * can be in just about any order, and it is likely to have clusters of
2421  * things that are close together and clusters of things that are not.
2422  *
2423  * To help reduce the seeks that come with updating all of these reference
2424  * counts, sort them by byte number before actual updates are done.
2425  *
2426  * struct refsort is used to match byte number to slot in the btree block.
2427  * we sort based on the byte number and then use the slot to actually
2428  * find the item.
2429  *
2430  * struct refsort is smaller than strcut btrfs_item and smaller than
2431  * struct btrfs_key_ptr.  Since we're currently limited to the page size
2432  * for a btree block, there's no way for a kmalloc of refsorts for a
2433  * single node to be bigger than a page.
2434  */
2435 struct refsort {
2436         u64 bytenr;
2437         u32 slot;
2438 };
2439
2440 /*
2441  * for passing into sort()
2442  */
2443 static int refsort_cmp(const void *a_void, const void *b_void)
2444 {
2445         const struct refsort *a = a_void;
2446         const struct refsort *b = b_void;
2447
2448         if (a->bytenr < b->bytenr)
2449                 return -1;
2450         if (a->bytenr > b->bytenr)
2451                 return 1;
2452         return 0;
2453 }
2454 #endif
2455
2456 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2457                            struct btrfs_root *root,
2458                            struct extent_buffer *buf,
2459                            int full_backref, int inc)
2460 {
2461         u64 bytenr;
2462         u64 num_bytes;
2463         u64 parent;
2464         u64 ref_root;
2465         u32 nritems;
2466         struct btrfs_key key;
2467         struct btrfs_file_extent_item *fi;
2468         int i;
2469         int level;
2470         int ret = 0;
2471         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2472                             u64, u64, u64, u64, u64, u64);
2473
2474         ref_root = btrfs_header_owner(buf);
2475         nritems = btrfs_header_nritems(buf);
2476         level = btrfs_header_level(buf);
2477
2478         if (!root->ref_cows && level == 0)
2479                 return 0;
2480
2481         if (inc)
2482                 process_func = btrfs_inc_extent_ref;
2483         else
2484                 process_func = btrfs_free_extent;
2485
2486         if (full_backref)
2487                 parent = buf->start;
2488         else
2489                 parent = 0;
2490
2491         for (i = 0; i < nritems; i++) {
2492                 if (level == 0) {
2493                         btrfs_item_key_to_cpu(buf, &key, i);
2494                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2495                                 continue;
2496                         fi = btrfs_item_ptr(buf, i,
2497                                             struct btrfs_file_extent_item);
2498                         if (btrfs_file_extent_type(buf, fi) ==
2499                             BTRFS_FILE_EXTENT_INLINE)
2500                                 continue;
2501                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2502                         if (bytenr == 0)
2503                                 continue;
2504
2505                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2506                         key.offset -= btrfs_file_extent_offset(buf, fi);
2507                         ret = process_func(trans, root, bytenr, num_bytes,
2508                                            parent, ref_root, key.objectid,
2509                                            key.offset);
2510                         if (ret)
2511                                 goto fail;
2512                 } else {
2513                         bytenr = btrfs_node_blockptr(buf, i);
2514                         num_bytes = btrfs_level_size(root, level - 1);
2515                         ret = process_func(trans, root, bytenr, num_bytes,
2516                                            parent, ref_root, level - 1, 0);
2517                         if (ret)
2518                                 goto fail;
2519                 }
2520         }
2521         return 0;
2522 fail:
2523         BUG();
2524         return ret;
2525 }
2526
2527 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2528                   struct extent_buffer *buf, int full_backref)
2529 {
2530         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2531 }
2532
2533 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2534                   struct extent_buffer *buf, int full_backref)
2535 {
2536         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2537 }
2538
2539 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2540                                  struct btrfs_root *root,
2541                                  struct btrfs_path *path,
2542                                  struct btrfs_block_group_cache *cache)
2543 {
2544         int ret;
2545         struct btrfs_root *extent_root = root->fs_info->extent_root;
2546         unsigned long bi;
2547         struct extent_buffer *leaf;
2548
2549         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2550         if (ret < 0)
2551                 goto fail;
2552         BUG_ON(ret);
2553
2554         leaf = path->nodes[0];
2555         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2556         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2557         btrfs_mark_buffer_dirty(leaf);
2558         btrfs_release_path(extent_root, path);
2559 fail:
2560         if (ret)
2561                 return ret;
2562         return 0;
2563
2564 }
2565
2566 static struct btrfs_block_group_cache *
2567 next_block_group(struct btrfs_root *root,
2568                  struct btrfs_block_group_cache *cache)
2569 {
2570         struct rb_node *node;
2571         spin_lock(&root->fs_info->block_group_cache_lock);
2572         node = rb_next(&cache->cache_node);
2573         btrfs_put_block_group(cache);
2574         if (node) {
2575                 cache = rb_entry(node, struct btrfs_block_group_cache,
2576                                  cache_node);
2577                 atomic_inc(&cache->count);
2578         } else
2579                 cache = NULL;
2580         spin_unlock(&root->fs_info->block_group_cache_lock);
2581         return cache;
2582 }
2583
2584 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2585                                    struct btrfs_root *root)
2586 {
2587         struct btrfs_block_group_cache *cache;
2588         int err = 0;
2589         struct btrfs_path *path;
2590         u64 last = 0;
2591
2592         path = btrfs_alloc_path();
2593         if (!path)
2594                 return -ENOMEM;
2595
2596         while (1) {
2597                 if (last == 0) {
2598                         err = btrfs_run_delayed_refs(trans, root,
2599                                                      (unsigned long)-1);
2600                         BUG_ON(err);
2601                 }
2602
2603                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2604                 while (cache) {
2605                         if (cache->dirty)
2606                                 break;
2607                         cache = next_block_group(root, cache);
2608                 }
2609                 if (!cache) {
2610                         if (last == 0)
2611                                 break;
2612                         last = 0;
2613                         continue;
2614                 }
2615
2616                 cache->dirty = 0;
2617                 last = cache->key.objectid + cache->key.offset;
2618
2619                 err = write_one_cache_group(trans, root, path, cache);
2620                 BUG_ON(err);
2621                 btrfs_put_block_group(cache);
2622         }
2623
2624         btrfs_free_path(path);
2625         return 0;
2626 }
2627
2628 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
2629 {
2630         struct btrfs_block_group_cache *block_group;
2631         int readonly = 0;
2632
2633         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
2634         if (!block_group || block_group->ro)
2635                 readonly = 1;
2636         if (block_group)
2637                 btrfs_put_block_group(block_group);
2638         return readonly;
2639 }
2640
2641 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
2642                              u64 total_bytes, u64 bytes_used,
2643                              struct btrfs_space_info **space_info)
2644 {
2645         struct btrfs_space_info *found;
2646
2647         found = __find_space_info(info, flags);
2648         if (found) {
2649                 spin_lock(&found->lock);
2650                 found->total_bytes += total_bytes;
2651                 found->bytes_used += bytes_used;
2652                 found->full = 0;
2653                 spin_unlock(&found->lock);
2654                 *space_info = found;
2655                 return 0;
2656         }
2657         found = kzalloc(sizeof(*found), GFP_NOFS);
2658         if (!found)
2659                 return -ENOMEM;
2660
2661         INIT_LIST_HEAD(&found->block_groups);
2662         init_rwsem(&found->groups_sem);
2663         spin_lock_init(&found->lock);
2664         found->flags = flags;
2665         found->total_bytes = total_bytes;
2666         found->bytes_used = bytes_used;
2667         found->bytes_pinned = 0;
2668         found->bytes_reserved = 0;
2669         found->bytes_readonly = 0;
2670         found->bytes_delalloc = 0;
2671         found->full = 0;
2672         found->force_alloc = 0;
2673         *space_info = found;
2674         list_add_rcu(&found->list, &info->space_info);
2675         atomic_set(&found->caching_threads, 0);
2676         return 0;
2677 }
2678
2679 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
2680 {
2681         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
2682                                    BTRFS_BLOCK_GROUP_RAID1 |
2683                                    BTRFS_BLOCK_GROUP_RAID10 |
2684                                    BTRFS_BLOCK_GROUP_DUP);
2685         if (extra_flags) {
2686                 if (flags & BTRFS_BLOCK_GROUP_DATA)
2687                         fs_info->avail_data_alloc_bits |= extra_flags;
2688                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
2689                         fs_info->avail_metadata_alloc_bits |= extra_flags;
2690                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2691                         fs_info->avail_system_alloc_bits |= extra_flags;
2692         }
2693 }
2694
2695 static void set_block_group_readonly(struct btrfs_block_group_cache *cache)
2696 {
2697         spin_lock(&cache->space_info->lock);
2698         spin_lock(&cache->lock);
2699         if (!cache->ro) {
2700                 cache->space_info->bytes_readonly += cache->key.offset -
2701                                         btrfs_block_group_used(&cache->item);
2702                 cache->ro = 1;
2703         }
2704         spin_unlock(&cache->lock);
2705         spin_unlock(&cache->space_info->lock);
2706 }
2707
2708 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
2709 {
2710         u64 num_devices = root->fs_info->fs_devices->rw_devices;
2711
2712         if (num_devices == 1)
2713                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
2714         if (num_devices < 4)
2715                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
2716
2717         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
2718             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
2719                       BTRFS_BLOCK_GROUP_RAID10))) {
2720                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
2721         }
2722
2723         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
2724             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
2725                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
2726         }
2727
2728         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
2729             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
2730              (flags & BTRFS_BLOCK_GROUP_RAID10) |
2731              (flags & BTRFS_BLOCK_GROUP_DUP)))
2732                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
2733         return flags;
2734 }
2735
2736 static u64 btrfs_get_alloc_profile(struct btrfs_root *root, u64 data)
2737 {
2738         struct btrfs_fs_info *info = root->fs_info;
2739         u64 alloc_profile;
2740
2741         if (data) {
2742                 alloc_profile = info->avail_data_alloc_bits &
2743                         info->data_alloc_profile;
2744                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
2745         } else if (root == root->fs_info->chunk_root) {
2746                 alloc_profile = info->avail_system_alloc_bits &
2747                         info->system_alloc_profile;
2748                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
2749         } else {
2750                 alloc_profile = info->avail_metadata_alloc_bits &
2751                         info->metadata_alloc_profile;
2752                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
2753         }
2754
2755         return btrfs_reduce_alloc_profile(root, data);
2756 }
2757
2758 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
2759 {
2760         u64 alloc_target;
2761
2762         alloc_target = btrfs_get_alloc_profile(root, 1);
2763         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
2764                                                        alloc_target);
2765 }
2766
2767 static u64 calculate_bytes_needed(struct btrfs_root *root, int num_items)
2768 {
2769         u64 num_bytes;
2770         int level;
2771
2772         level = BTRFS_MAX_LEVEL - 2;
2773         /*
2774          * NOTE: these calculations are absolutely the worst possible case.
2775          * This assumes that _every_ item we insert will require a new leaf, and
2776          * that the tree has grown to its maximum level size.
2777          */
2778
2779         /*
2780          * for every item we insert we could insert both an extent item and a
2781          * extent ref item.  Then for ever item we insert, we will need to cow
2782          * both the original leaf, plus the leaf to the left and right of it.
2783          *
2784          * Unless we are talking about the extent root, then we just want the
2785          * number of items * 2, since we just need the extent item plus its ref.
2786          */
2787         if (root == root->fs_info->extent_root)
2788                 num_bytes = num_items * 2;
2789         else
2790                 num_bytes = (num_items + (2 * num_items)) * 3;
2791
2792         /*
2793          * num_bytes is total number of leaves we could need times the leaf
2794          * size, and then for every leaf we could end up cow'ing 2 nodes per
2795          * level, down to the leaf level.
2796          */
2797         num_bytes = (num_bytes * root->leafsize) +
2798                 (num_bytes * (level * 2)) * root->nodesize;
2799
2800         return num_bytes;
2801 }
2802
2803 /*
2804  * Unreserve metadata space for delalloc.  If we have less reserved credits than
2805  * we have extents, this function does nothing.
2806  */
2807 int btrfs_unreserve_metadata_for_delalloc(struct btrfs_root *root,
2808                                           struct inode *inode, int num_items)
2809 {
2810         struct btrfs_fs_info *info = root->fs_info;
2811         struct btrfs_space_info *meta_sinfo;
2812         u64 num_bytes;
2813         u64 alloc_target;
2814         bool bug = false;
2815
2816         /* get the space info for where the metadata will live */
2817         alloc_target = btrfs_get_alloc_profile(root, 0);
2818         meta_sinfo = __find_space_info(info, alloc_target);
2819
2820         num_bytes = calculate_bytes_needed(root->fs_info->extent_root,
2821                                            num_items);
2822
2823         spin_lock(&meta_sinfo->lock);
2824         spin_lock(&BTRFS_I(inode)->accounting_lock);
2825         if (BTRFS_I(inode)->reserved_extents <=
2826             BTRFS_I(inode)->outstanding_extents) {
2827                 spin_unlock(&BTRFS_I(inode)->accounting_lock);
2828                 spin_unlock(&meta_sinfo->lock);
2829                 return 0;
2830         }
2831         spin_unlock(&BTRFS_I(inode)->accounting_lock);
2832
2833         BTRFS_I(inode)->reserved_extents--;
2834         BUG_ON(BTRFS_I(inode)->reserved_extents < 0);
2835
2836         if (meta_sinfo->bytes_delalloc < num_bytes) {
2837                 bug = true;
2838                 meta_sinfo->bytes_delalloc = 0;
2839         } else {
2840                 meta_sinfo->bytes_delalloc -= num_bytes;
2841         }
2842         spin_unlock(&meta_sinfo->lock);
2843
2844         BUG_ON(bug);
2845
2846         return 0;
2847 }
2848
2849 static void check_force_delalloc(struct btrfs_space_info *meta_sinfo)
2850 {
2851         u64 thresh;
2852
2853         thresh = meta_sinfo->bytes_used + meta_sinfo->bytes_reserved +
2854                 meta_sinfo->bytes_pinned + meta_sinfo->bytes_readonly +
2855                 meta_sinfo->bytes_super + meta_sinfo->bytes_root +
2856                 meta_sinfo->bytes_may_use;
2857
2858         thresh = meta_sinfo->total_bytes - thresh;
2859         thresh *= 80;
2860         do_div(thresh, 100);
2861         if (thresh <= meta_sinfo->bytes_delalloc)
2862                 meta_sinfo->force_delalloc = 1;
2863         else
2864                 meta_sinfo->force_delalloc = 0;
2865 }
2866
2867 struct async_flush {
2868         struct btrfs_root *root;
2869         struct btrfs_space_info *info;
2870         struct btrfs_work work;
2871 };
2872
2873 static noinline void flush_delalloc_async(struct btrfs_work *work)
2874 {
2875         struct async_flush *async;
2876         struct btrfs_root *root;
2877         struct btrfs_space_info *info;
2878
2879         async = container_of(work, struct async_flush, work);
2880         root = async->root;
2881         info = async->info;
2882
2883         btrfs_start_delalloc_inodes(root, 0);
2884         wake_up(&info->flush_wait);
2885         btrfs_wait_ordered_extents(root, 0, 0);
2886
2887         spin_lock(&info->lock);
2888         info->flushing = 0;
2889         spin_unlock(&info->lock);
2890         wake_up(&info->flush_wait);
2891
2892         kfree(async);
2893 }
2894
2895 static void wait_on_flush(struct btrfs_space_info *info)
2896 {
2897         DEFINE_WAIT(wait);
2898         u64 used;
2899
2900         while (1) {
2901                 prepare_to_wait(&info->flush_wait, &wait,
2902                                 TASK_UNINTERRUPTIBLE);
2903                 spin_lock(&info->lock);
2904                 if (!info->flushing) {
2905                         spin_unlock(&info->lock);
2906                         break;
2907                 }
2908
2909                 used = info->bytes_used + info->bytes_reserved +
2910                         info->bytes_pinned + info->bytes_readonly +
2911                         info->bytes_super + info->bytes_root +
2912                         info->bytes_may_use + info->bytes_delalloc;
2913                 if (used < info->total_bytes) {
2914                         spin_unlock(&info->lock);
2915                         break;
2916                 }
2917                 spin_unlock(&info->lock);
2918                 schedule();
2919         }
2920         finish_wait(&info->flush_wait, &wait);
2921 }
2922
2923 static void flush_delalloc(struct btrfs_root *root,
2924                                  struct btrfs_space_info *info)
2925 {
2926         struct async_flush *async;
2927         bool wait = false;
2928
2929         spin_lock(&info->lock);
2930
2931         if (!info->flushing) {
2932                 info->flushing = 1;
2933                 init_waitqueue_head(&info->flush_wait);
2934         } else {
2935                 wait = true;
2936         }
2937
2938         spin_unlock(&info->lock);
2939
2940         if (wait) {
2941                 wait_on_flush(info);
2942                 return;
2943         }
2944
2945         async = kzalloc(sizeof(*async), GFP_NOFS);
2946         if (!async)
2947                 goto flush;
2948
2949         async->root = root;
2950         async->info = info;
2951         async->work.func = flush_delalloc_async;
2952
2953         btrfs_queue_worker(&root->fs_info->enospc_workers,
2954                            &async->work);
2955         wait_on_flush(info);
2956         return;
2957
2958 flush:
2959         btrfs_start_delalloc_inodes(root, 0);
2960         btrfs_wait_ordered_extents(root, 0, 0);
2961
2962         spin_lock(&info->lock);
2963         info->flushing = 0;
2964         spin_unlock(&info->lock);
2965         wake_up(&info->flush_wait);
2966 }
2967
2968 static int maybe_allocate_chunk(struct btrfs_root *root,
2969                                  struct btrfs_space_info *info)
2970 {
2971         struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
2972         struct btrfs_trans_handle *trans;
2973         bool wait = false;
2974         int ret = 0;
2975         u64 min_metadata;
2976         u64 free_space;
2977
2978         free_space = btrfs_super_total_bytes(disk_super);
2979         /*
2980          * we allow the metadata to grow to a max of either 10gb or 5% of the
2981          * space in the volume.
2982          */
2983         min_metadata = min((u64)10 * 1024 * 1024 * 1024,
2984                              div64_u64(free_space * 5, 100));
2985         if (info->total_bytes >= min_metadata) {
2986                 spin_unlock(&info->lock);
2987                 return 0;
2988         }
2989
2990         if (info->full) {
2991                 spin_unlock(&info->lock);
2992                 return 0;
2993         }
2994
2995         if (!info->allocating_chunk) {
2996                 info->force_alloc = 1;
2997                 info->allocating_chunk = 1;
2998                 init_waitqueue_head(&info->allocate_wait);
2999         } else {
3000                 wait = true;
3001         }
3002
3003         spin_unlock(&info->lock);
3004
3005         if (wait) {
3006                 wait_event(info->allocate_wait,
3007                            !info->allocating_chunk);
3008                 return 1;
3009         }
3010
3011         trans = btrfs_start_transaction(root, 1);
3012         if (!trans) {
3013                 ret = -ENOMEM;
3014                 goto out;
3015         }
3016
3017         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3018                              4096 + 2 * 1024 * 1024,
3019                              info->flags, 0);
3020         btrfs_end_transaction(trans, root);
3021         if (ret)
3022                 goto out;
3023 out:
3024         spin_lock(&info->lock);
3025         info->allocating_chunk = 0;
3026         spin_unlock(&info->lock);
3027         wake_up(&info->allocate_wait);
3028
3029         if (ret)
3030                 return 0;
3031         return 1;
3032 }
3033
3034 /*
3035  * Reserve metadata space for delalloc.
3036  */
3037 int btrfs_reserve_metadata_for_delalloc(struct btrfs_root *root,
3038                                         struct inode *inode, int num_items)
3039 {
3040         struct btrfs_fs_info *info = root->fs_info;
3041         struct btrfs_space_info *meta_sinfo;
3042         u64 num_bytes;
3043         u64 used;
3044         u64 alloc_target;
3045         int flushed = 0;
3046         int force_delalloc;
3047
3048         /* get the space info for where the metadata will live */
3049         alloc_target = btrfs_get_alloc_profile(root, 0);
3050         meta_sinfo = __find_space_info(info, alloc_target);
3051
3052         num_bytes = calculate_bytes_needed(root->fs_info->extent_root,
3053                                            num_items);
3054 again:
3055         spin_lock(&meta_sinfo->lock);
3056
3057         force_delalloc = meta_sinfo->force_delalloc;
3058
3059         if (unlikely(!meta_sinfo->bytes_root))
3060                 meta_sinfo->bytes_root = calculate_bytes_needed(root, 6);
3061
3062         if (!flushed)
3063                 meta_sinfo->bytes_delalloc += num_bytes;
3064
3065         used = meta_sinfo->bytes_used + meta_sinfo->bytes_reserved +
3066                 meta_sinfo->bytes_pinned + meta_sinfo->bytes_readonly +
3067                 meta_sinfo->bytes_super + meta_sinfo->bytes_root +
3068                 meta_sinfo->bytes_may_use + meta_sinfo->bytes_delalloc;
3069
3070         if (used > meta_sinfo->total_bytes) {
3071                 flushed++;
3072
3073                 if (flushed == 1) {
3074                         if (maybe_allocate_chunk(root, meta_sinfo))
3075                                 goto again;
3076                         flushed++;
3077                 } else {
3078                         spin_unlock(&meta_sinfo->lock);
3079                 }
3080
3081                 if (flushed == 2) {
3082                         filemap_flush(inode->i_mapping);
3083                         goto again;
3084                 } else if (flushed == 3) {
3085                         flush_delalloc(root, meta_sinfo);
3086                         goto again;
3087                 }
3088                 spin_lock(&meta_sinfo->lock);
3089                 meta_sinfo->bytes_delalloc -= num_bytes;
3090                 spin_unlock(&meta_sinfo->lock);
3091                 printk(KERN_ERR "enospc, has %d, reserved %d\n",
3092                        BTRFS_I(inode)->outstanding_extents,
3093                        BTRFS_I(inode)->reserved_extents);
3094                 dump_space_info(meta_sinfo, 0, 0);
3095                 return -ENOSPC;
3096         }
3097
3098         BTRFS_I(inode)->reserved_extents++;
3099         check_force_delalloc(meta_sinfo);
3100         spin_unlock(&meta_sinfo->lock);
3101
3102         if (!flushed && force_delalloc)
3103                 filemap_flush(inode->i_mapping);
3104
3105         return 0;
3106 }
3107
3108 /*
3109  * unreserve num_items number of items worth of metadata space.  This needs to
3110  * be paired with btrfs_reserve_metadata_space.
3111  *
3112  * NOTE: if you have the option, run this _AFTER_ you do a
3113  * btrfs_end_transaction, since btrfs_end_transaction will run delayed ref
3114  * oprations which will result in more used metadata, so we want to make sure we
3115  * can do that without issue.
3116  */
3117 int btrfs_unreserve_metadata_space(struct btrfs_root *root, int num_items)
3118 {
3119         struct btrfs_fs_info *info = root->fs_info;
3120         struct btrfs_space_info *meta_sinfo;
3121         u64 num_bytes;
3122         u64 alloc_target;
3123         bool bug = false;
3124
3125         /* get the space info for where the metadata will live */
3126         alloc_target = btrfs_get_alloc_profile(root, 0);
3127         meta_sinfo = __find_space_info(info, alloc_target);
3128
3129         num_bytes = calculate_bytes_needed(root, num_items);
3130
3131         spin_lock(&meta_sinfo->lock);
3132         if (meta_sinfo->bytes_may_use < num_bytes) {
3133                 bug = true;
3134                 meta_sinfo->bytes_may_use = 0;
3135         } else {
3136                 meta_sinfo->bytes_may_use -= num_bytes;
3137         }
3138         spin_unlock(&meta_sinfo->lock);
3139
3140         BUG_ON(bug);
3141
3142         return 0;
3143 }
3144
3145 /*
3146  * Reserve some metadata space for use.  We'll calculate the worste case number
3147  * of bytes that would be needed to modify num_items number of items.  If we
3148  * have space, fantastic, if not, you get -ENOSPC.  Please call
3149  * btrfs_unreserve_metadata_space when you are done for the _SAME_ number of
3150  * items you reserved, since whatever metadata you needed should have already
3151  * been allocated.
3152  *
3153  * This will commit the transaction to make more space if we don't have enough
3154  * metadata space.  THe only time we don't do this is if we're reserving space
3155  * inside of a transaction, then we will just return -ENOSPC and it is the
3156  * callers responsibility to handle it properly.
3157  */
3158 int btrfs_reserve_metadata_space(struct btrfs_root *root, int num_items)
3159 {
3160         struct btrfs_fs_info *info = root->fs_info;
3161         struct btrfs_space_info *meta_sinfo;
3162         u64 num_bytes;
3163         u64 used;
3164         u64 alloc_target;
3165         int retries = 0;
3166
3167         /* get the space info for where the metadata will live */
3168         alloc_target = btrfs_get_alloc_profile(root, 0);
3169         meta_sinfo = __find_space_info(info, alloc_target);
3170
3171         num_bytes = calculate_bytes_needed(root, num_items);
3172 again:
3173         spin_lock(&meta_sinfo->lock);
3174
3175         if (unlikely(!meta_sinfo->bytes_root))
3176                 meta_sinfo->bytes_root = calculate_bytes_needed(root, 6);
3177
3178         if (!retries)
3179                 meta_sinfo->bytes_may_use += num_bytes;
3180
3181         used = meta_sinfo->bytes_used + meta_sinfo->bytes_reserved +
3182                 meta_sinfo->bytes_pinned + meta_sinfo->bytes_readonly +
3183                 meta_sinfo->bytes_super + meta_sinfo->bytes_root +
3184                 meta_sinfo->bytes_may_use + meta_sinfo->bytes_delalloc;
3185
3186         if (used > meta_sinfo->total_bytes) {
3187                 retries++;
3188                 if (retries == 1) {
3189                         if (maybe_allocate_chunk(root, meta_sinfo))
3190                                 goto again;
3191                         retries++;
3192                 } else {
3193                         spin_unlock(&meta_sinfo->lock);
3194                 }
3195
3196                 if (retries == 2) {
3197                         flush_delalloc(root, meta_sinfo);
3198                         goto again;
3199                 }
3200                 spin_lock(&meta_sinfo->lock);
3201                 meta_sinfo->bytes_may_use -= num_bytes;
3202                 spin_unlock(&meta_sinfo->lock);
3203
3204                 dump_space_info(meta_sinfo, 0, 0);
3205                 return -ENOSPC;
3206         }
3207
3208         check_force_delalloc(meta_sinfo);
3209         spin_unlock(&meta_sinfo->lock);
3210
3211         return 0;
3212 }
3213
3214 /*
3215  * This will check the space that the inode allocates from to make sure we have
3216  * enough space for bytes.
3217  */
3218 int btrfs_check_data_free_space(struct btrfs_root *root, struct inode *inode,
3219                                 u64 bytes)
3220 {
3221         struct btrfs_space_info *data_sinfo;
3222         int ret = 0, committed = 0;
3223
3224         /* make sure bytes are sectorsize aligned */
3225         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3226
3227         data_sinfo = BTRFS_I(inode)->space_info;
3228         if (!data_sinfo)
3229                 goto alloc;
3230
3231 again:
3232         /* make sure we have enough space to handle the data first */
3233         spin_lock(&data_sinfo->lock);
3234         if (data_sinfo->total_bytes - data_sinfo->bytes_used -
3235             data_sinfo->bytes_delalloc - data_sinfo->bytes_reserved -
3236             data_sinfo->bytes_pinned - data_sinfo->bytes_readonly -
3237             data_sinfo->bytes_may_use - data_sinfo->bytes_super < bytes) {
3238                 struct btrfs_trans_handle *trans;
3239
3240                 /*
3241                  * if we don't have enough free bytes in this space then we need
3242                  * to alloc a new chunk.
3243                  */
3244                 if (!data_sinfo->full) {
3245                         u64 alloc_target;
3246
3247                         data_sinfo->force_alloc = 1;
3248                         spin_unlock(&data_sinfo->lock);
3249 alloc:
3250                         alloc_target = btrfs_get_alloc_profile(root, 1);
3251                         trans = btrfs_start_transaction(root, 1);
3252                         if (!trans)
3253                                 return -ENOMEM;
3254
3255                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3256                                              bytes + 2 * 1024 * 1024,
3257                                              alloc_target, 0);
3258                         btrfs_end_transaction(trans, root);
3259                         if (ret)
3260                                 return ret;
3261
3262                         if (!data_sinfo) {
3263                                 btrfs_set_inode_space_info(root, inode);
3264                                 data_sinfo = BTRFS_I(inode)->space_info;
3265                         }
3266                         goto again;
3267                 }
3268                 spin_unlock(&data_sinfo->lock);
3269
3270                 /* commit the current transaction and try again */
3271                 if (!committed && !root->fs_info->open_ioctl_trans) {
3272                         committed = 1;
3273                         trans = btrfs_join_transaction(root, 1);
3274                         if (!trans)
3275                                 return -ENOMEM;
3276                         ret = btrfs_commit_transaction(trans, root);
3277                         if (ret)
3278                                 return ret;
3279                         goto again;
3280                 }
3281
3282                 printk(KERN_ERR "no space left, need %llu, %llu delalloc bytes"
3283                        ", %llu bytes_used, %llu bytes_reserved, "
3284                        "%llu bytes_pinned, %llu bytes_readonly, %llu may use "
3285                        "%llu total\n", (unsigned long long)bytes,
3286                        (unsigned long long)data_sinfo->bytes_delalloc,
3287                        (unsigned long long)data_sinfo->bytes_used,
3288                        (unsigned long long)data_sinfo->bytes_reserved,
3289                        (unsigned long long)data_sinfo->bytes_pinned,
3290                        (unsigned long long)data_sinfo->bytes_readonly,
3291                        (unsigned long long)data_sinfo->bytes_may_use,
3292                        (unsigned long long)data_sinfo->total_bytes);
3293                 return -ENOSPC;
3294         }
3295         data_sinfo->bytes_may_use += bytes;
3296         BTRFS_I(inode)->reserved_bytes += bytes;
3297         spin_unlock(&data_sinfo->lock);
3298
3299         return 0;
3300 }
3301
3302 /*
3303  * if there was an error for whatever reason after calling
3304  * btrfs_check_data_free_space, call this so we can cleanup the counters.
3305  */
3306 void btrfs_free_reserved_data_space(struct btrfs_root *root,
3307                                     struct inode *inode, u64 bytes)
3308 {
3309         struct btrfs_space_info *data_sinfo;
3310
3311         /* make sure bytes are sectorsize aligned */
3312         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3313
3314         data_sinfo = BTRFS_I(inode)->space_info;
3315         spin_lock(&data_sinfo->lock);
3316         data_sinfo->bytes_may_use -= bytes;
3317         BTRFS_I(inode)->reserved_bytes -= bytes;
3318         spin_unlock(&data_sinfo->lock);
3319 }
3320
3321 /* called when we are adding a delalloc extent to the inode's io_tree */
3322 void btrfs_delalloc_reserve_space(struct btrfs_root *root, struct inode *inode,
3323                                   u64 bytes)
3324 {
3325         struct btrfs_space_info *data_sinfo;
3326
3327         /* get the space info for where this inode will be storing its data */
3328         data_sinfo = BTRFS_I(inode)->space_info;
3329
3330         /* make sure we have enough space to handle the data first */
3331         spin_lock(&data_sinfo->lock);
3332         data_sinfo->bytes_delalloc += bytes;
3333
3334         /*
3335          * we are adding a delalloc extent without calling
3336          * btrfs_check_data_free_space first.  This happens on a weird
3337          * writepage condition, but shouldn't hurt our accounting
3338          */
3339         if (unlikely(bytes > BTRFS_I(inode)->reserved_bytes)) {
3340                 data_sinfo->bytes_may_use -= BTRFS_I(inode)->reserved_bytes;
3341                 BTRFS_I(inode)->reserved_bytes = 0;
3342         } else {
3343                 data_sinfo->bytes_may_use -= bytes;
3344                 BTRFS_I(inode)->reserved_bytes -= bytes;
3345         }
3346
3347         spin_unlock(&data_sinfo->lock);
3348 }
3349
3350 /* called when we are clearing an delalloc extent from the inode's io_tree */
3351 void btrfs_delalloc_free_space(struct btrfs_root *root, struct inode *inode,
3352                               u64 bytes)
3353 {
3354         struct btrfs_space_info *info;
3355
3356         info = BTRFS_I(inode)->space_info;
3357
3358         spin_lock(&info->lock);
3359         info->bytes_delalloc -= bytes;
3360         spin_unlock(&info->lock);
3361 }
3362
3363 static void force_metadata_allocation(struct btrfs_fs_info *info)
3364 {
3365         struct list_head *head = &info->space_info;
3366         struct btrfs_space_info *found;
3367
3368         rcu_read_lock();
3369         list_for_each_entry_rcu(found, head, list) {
3370                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3371                         found->force_alloc = 1;
3372         }
3373         rcu_read_unlock();
3374 }
3375
3376 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3377                           struct btrfs_root *extent_root, u64 alloc_bytes,
3378                           u64 flags, int force)
3379 {
3380         struct btrfs_space_info *space_info;
3381         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3382         u64 thresh;
3383         int ret = 0;
3384
3385         mutex_lock(&fs_info->chunk_mutex);
3386
3387         flags = btrfs_reduce_alloc_profile(extent_root, flags);
3388
3389         space_info = __find_space_info(extent_root->fs_info, flags);
3390         if (!space_info) {
3391                 ret = update_space_info(extent_root->fs_info, flags,
3392                                         0, 0, &space_info);
3393                 BUG_ON(ret);
3394         }
3395         BUG_ON(!space_info);
3396
3397         spin_lock(&space_info->lock);
3398         if (space_info->force_alloc)
3399                 force = 1;
3400         if (space_info->full) {
3401                 spin_unlock(&space_info->lock);
3402                 goto out;
3403         }
3404
3405         thresh = space_info->total_bytes - space_info->bytes_readonly;
3406         thresh = div_factor(thresh, 8);
3407         if (!force &&
3408            (space_info->bytes_used + space_info->bytes_pinned +
3409             space_info->bytes_reserved + alloc_bytes) < thresh) {
3410                 spin_unlock(&space_info->lock);
3411                 goto out;
3412         }
3413         spin_unlock(&space_info->lock);
3414
3415         /*
3416          * if we're doing a data chunk, go ahead and make sure that
3417          * we keep a reasonable number of metadata chunks allocated in the
3418          * FS as well.
3419          */
3420         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3421                 fs_info->data_chunk_allocations++;
3422                 if (!(fs_info->data_chunk_allocations %
3423                       fs_info->metadata_ratio))
3424                         force_metadata_allocation(fs_info);
3425         }
3426
3427         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3428         spin_lock(&space_info->lock);
3429         if (ret)
3430                 space_info->full = 1;
3431         space_info->force_alloc = 0;
3432         spin_unlock(&space_info->lock);
3433 out:
3434         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3435         return ret;
3436 }
3437
3438 static int update_block_group(struct btrfs_trans_handle *trans,
3439                               struct btrfs_root *root,
3440                               u64 bytenr, u64 num_bytes, int alloc,
3441                               int mark_free)
3442 {
3443         struct btrfs_block_group_cache *cache;
3444         struct btrfs_fs_info *info = root->fs_info;
3445         u64 total = num_bytes;
3446         u64 old_val;
3447         u64 byte_in_group;
3448
3449         /* block accounting for super block */
3450         spin_lock(&info->delalloc_lock);
3451         old_val = btrfs_super_bytes_used(&info->super_copy);
3452         if (alloc)
3453                 old_val += num_bytes;
3454         else
3455                 old_val -= num_bytes;
3456         btrfs_set_super_bytes_used(&info->super_copy, old_val);
3457
3458         /* block accounting for root item */
3459         old_val = btrfs_root_used(&root->root_item);
3460         if (alloc)
3461                 old_val += num_bytes;
3462         else
3463                 old_val -= num_bytes;
3464         btrfs_set_root_used(&root->root_item, old_val);
3465         spin_unlock(&info->delalloc_lock);
3466
3467         while (total) {
3468                 cache = btrfs_lookup_block_group(info, bytenr);
3469                 if (!cache)
3470                         return -1;
3471                 byte_in_group = bytenr - cache->key.objectid;
3472                 WARN_ON(byte_in_group > cache->key.offset);
3473
3474                 spin_lock(&cache->space_info->lock);
3475                 spin_lock(&cache->lock);
3476                 cache->dirty = 1;
3477                 old_val = btrfs_block_group_used(&cache->item);
3478                 num_bytes = min(total, cache->key.offset - byte_in_group);
3479                 if (alloc) {
3480                         old_val += num_bytes;
3481                         btrfs_set_block_group_used(&cache->item, old_val);
3482                         cache->reserved -= num_bytes;
3483                         cache->space_info->bytes_used += num_bytes;
3484                         cache->space_info->bytes_reserved -= num_bytes;
3485                         if (cache->ro)
3486                                 cache->space_info->bytes_readonly -= num_bytes;
3487                         spin_unlock(&cache->lock);
3488                         spin_unlock(&cache->space_info->lock);
3489                 } else {
3490                         old_val -= num_bytes;
3491                         cache->space_info->bytes_used -= num_bytes;
3492                         if (cache->ro)
3493                                 cache->space_info->bytes_readonly += num_bytes;
3494                         btrfs_set_block_group_used(&cache->item, old_val);
3495                         spin_unlock(&cache->lock);
3496                         spin_unlock(&cache->space_info->lock);
3497                         if (mark_free) {
3498                                 int ret;
3499
3500                                 ret = btrfs_discard_extent(root, bytenr,
3501                                                            num_bytes);
3502                                 WARN_ON(ret);
3503
3504                                 ret = btrfs_add_free_space(cache, bytenr,
3505                                                            num_bytes);
3506                                 WARN_ON(ret);
3507                         }
3508                 }
3509                 btrfs_put_block_group(cache);
3510                 total -= num_bytes;
3511                 bytenr += num_bytes;
3512         }
3513         return 0;
3514 }
3515
3516 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
3517 {
3518         struct btrfs_block_group_cache *cache;
3519         u64 bytenr;
3520
3521         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
3522         if (!cache)
3523                 return 0;
3524
3525         bytenr = cache->key.objectid;
3526         btrfs_put_block_group(cache);
3527
3528         return bytenr;
3529 }
3530
3531 /*
3532  * this function must be called within transaction
3533  */
3534 int btrfs_pin_extent(struct btrfs_root *root,
3535                      u64 bytenr, u64 num_bytes, int reserved)
3536 {
3537         struct btrfs_fs_info *fs_info = root->fs_info;
3538         struct btrfs_block_group_cache *cache;
3539
3540         cache = btrfs_lookup_block_group(fs_info, bytenr);
3541         BUG_ON(!cache);
3542
3543         spin_lock(&cache->space_info->lock);
3544         spin_lock(&cache->lock);
3545         cache->pinned += num_bytes;
3546         cache->space_info->bytes_pinned += num_bytes;
3547         if (reserved) {
3548                 cache->reserved -= num_bytes;
3549                 cache->space_info->bytes_reserved -= num_bytes;
3550         }
3551         spin_unlock(&cache->lock);
3552         spin_unlock(&cache->space_info->lock);
3553
3554         btrfs_put_block_group(cache);
3555
3556         set_extent_dirty(fs_info->pinned_extents,
3557                          bytenr, bytenr + num_bytes - 1, GFP_NOFS);
3558         return 0;
3559 }
3560
3561 static int update_reserved_extents(struct btrfs_block_group_cache *cache,
3562                                    u64 num_bytes, int reserve)
3563 {
3564         spin_lock(&cache->space_info->lock);
3565         spin_lock(&cache->lock);
3566         if (reserve) {
3567                 cache->reserved += num_bytes;
3568                 cache->space_info->bytes_reserved += num_bytes;
3569         } else {
3570                 cache->reserved -= num_bytes;
3571                 cache->space_info->bytes_reserved -= num_bytes;
3572         }
3573         spin_unlock(&cache->lock);
3574         spin_unlock(&cache->space_info->lock);
3575         return 0;
3576 }
3577
3578 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
3579                                 struct btrfs_root *root)
3580 {
3581         struct btrfs_fs_info *fs_info = root->fs_info;
3582         struct btrfs_caching_control *next;
3583         struct btrfs_caching_control *caching_ctl;
3584         struct btrfs_block_group_cache *cache;
3585
3586         down_write(&fs_info->extent_commit_sem);
3587
3588         list_for_each_entry_safe(caching_ctl, next,
3589                                  &fs_info->caching_block_groups, list) {
3590                 cache = caching_ctl->block_group;
3591                 if (block_group_cache_done(cache)) {
3592                         cache->last_byte_to_unpin = (u64)-1;
3593                         list_del_init(&caching_ctl->list);
3594                         put_caching_control(caching_ctl);
3595                 } else {
3596                         cache->last_byte_to_unpin = caching_ctl->progress;
3597                 }
3598         }
3599
3600         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
3601                 fs_info->pinned_extents = &fs_info->freed_extents[1];
3602         else
3603                 fs_info->pinned_extents = &fs_info->freed_extents[0];
3604
3605         up_write(&fs_info->extent_commit_sem);
3606         return 0;
3607 }
3608
3609 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
3610 {
3611         struct btrfs_fs_info *fs_info = root->fs_info;
3612         struct btrfs_block_group_cache *cache = NULL;
3613         u64 len;
3614
3615         while (start <= end) {
3616                 if (!cache ||
3617                     start >= cache->key.objectid + cache->key.offset) {
3618                         if (cache)
3619                                 btrfs_put_block_group(cache);
3620                         cache = btrfs_lookup_block_group(fs_info, start);
3621                         BUG_ON(!cache);
3622                 }
3623
3624                 len = cache->key.objectid + cache->key.offset - start;
3625                 len = min(len, end + 1 - start);
3626
3627                 if (start < cache->last_byte_to_unpin) {
3628                         len = min(len, cache->last_byte_to_unpin - start);
3629                         btrfs_add_free_space(cache, start, len);
3630                 }
3631
3632                 spin_lock(&cache->space_info->lock);
3633                 spin_lock(&cache->lock);
3634                 cache->pinned -= len;
3635                 cache->space_info->bytes_pinned -= len;
3636                 spin_unlock(&cache->lock);
3637                 spin_unlock(&cache->space_info->lock);
3638
3639                 start += len;
3640         }
3641
3642         if (cache)
3643                 btrfs_put_block_group(cache);
3644         return 0;
3645 }
3646
3647 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
3648                                struct btrfs_root *root)
3649 {
3650         struct btrfs_fs_info *fs_info = root->fs_info;
3651         struct extent_io_tree *unpin;
3652         u64 start;
3653         u64 end;
3654         int ret;
3655
3656         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
3657                 unpin = &fs_info->freed_extents[1];
3658         else
3659                 unpin = &fs_info->freed_extents[0];
3660
3661         while (1) {
3662                 ret = find_first_extent_bit(unpin, 0, &start, &end,
3663                                             EXTENT_DIRTY);
3664                 if (ret)
3665                         break;
3666
3667                 ret = btrfs_discard_extent(root, start, end + 1 - start);
3668
3669                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
3670                 unpin_extent_range(root, start, end);
3671                 cond_resched();
3672         }
3673
3674         return ret;
3675 }
3676
3677 static int pin_down_bytes(struct btrfs_trans_handle *trans,
3678                           struct btrfs_root *root,
3679                           struct btrfs_path *path,
3680                           u64 bytenr, u64 num_bytes,
3681                           int is_data, int reserved,
3682                           struct extent_buffer **must_clean)
3683 {
3684         int err = 0;
3685         struct extent_buffer *buf;
3686
3687         if (is_data)
3688                 goto pinit;
3689
3690         /*
3691          * discard is sloooow, and so triggering discards on
3692          * individual btree blocks isn't a good plan.  Just
3693          * pin everything in discard mode.
3694          */
3695         if (btrfs_test_opt(root, DISCARD))
3696                 goto pinit;
3697
3698         buf = btrfs_find_tree_block(root, bytenr, num_bytes);
3699         if (!buf)
3700                 goto pinit;
3701
3702         /* we can reuse a block if it hasn't been written
3703          * and it is from this transaction.  We can't
3704          * reuse anything from the tree log root because
3705          * it has tiny sub-transactions.
3706          */
3707         if (btrfs_buffer_uptodate(buf, 0) &&
3708             btrfs_try_tree_lock(buf)) {
3709                 u64 header_owner = btrfs_header_owner(buf);
3710                 u64 header_transid = btrfs_header_generation(buf);
3711                 if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
3712                     header_transid == trans->transid &&
3713                     !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
3714                         *must_clean = buf;
3715                         return 1;
3716                 }
3717                 btrfs_tree_unlock(buf);
3718         }
3719         free_extent_buffer(buf);
3720 pinit:
3721         if (path)
3722                 btrfs_set_path_blocking(path);
3723         /* unlocks the pinned mutex */
3724         btrfs_pin_extent(root, bytenr, num_bytes, reserved);
3725
3726         BUG_ON(err < 0);
3727         return 0;
3728 }
3729
3730 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
3731                                 struct btrfs_root *root,
3732                                 u64 bytenr, u64 num_bytes, u64 parent,
3733                                 u64 root_objectid, u64 owner_objectid,
3734                                 u64 owner_offset, int refs_to_drop,
3735                                 struct btrfs_delayed_extent_op *extent_op)
3736 {
3737         struct btrfs_key key;
3738         struct btrfs_path *path;
3739         struct btrfs_fs_info *info = root->fs_info;
3740         struct btrfs_root *extent_root = info->extent_root;
3741         struct extent_buffer *leaf;
3742         struct btrfs_extent_item *ei;
3743         struct btrfs_extent_inline_ref *iref;
3744         int ret;
3745         int is_data;
3746         int extent_slot = 0;
3747         int found_extent = 0;
3748         int num_to_del = 1;
3749         u32 item_size;
3750         u64 refs;
3751
3752         path = btrfs_alloc_path();
3753         if (!path)
3754                 return -ENOMEM;
3755
3756         path->reada = 1;
3757         path->leave_spinning = 1;
3758
3759         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
3760         BUG_ON(!is_data && refs_to_drop != 1);
3761
3762         ret = lookup_extent_backref(trans, extent_root, path, &iref,
3763                                     bytenr, num_bytes, parent,
3764                                     root_objectid, owner_objectid,
3765                                     owner_offset);
3766         if (ret == 0) {
3767                 extent_slot = path->slots[0];
3768                 while (extent_slot >= 0) {
3769                         btrfs_item_key_to_cpu(path->nodes[0], &key,
3770                                               extent_slot);
3771                         if (key.objectid != bytenr)
3772                                 break;
3773                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3774                             key.offset == num_bytes) {
3775                                 found_extent = 1;
3776                                 break;
3777                         }
3778                         if (path->slots[0] - extent_slot > 5)
3779                                 break;
3780                         extent_slot--;
3781                 }
3782 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3783                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
3784                 if (found_extent && item_size < sizeof(*ei))
3785                         found_extent = 0;
3786 #endif
3787                 if (!found_extent) {
3788                         BUG_ON(iref);
3789                         ret = remove_extent_backref(trans, extent_root, path,
3790                                                     NULL, refs_to_drop,
3791                                                     is_data);
3792                         BUG_ON(ret);
3793                         btrfs_release_path(extent_root, path);
3794                         path->leave_spinning = 1;
3795
3796                         key.objectid = bytenr;
3797                         key.type = BTRFS_EXTENT_ITEM_KEY;
3798                         key.offset = num_bytes;
3799
3800                         ret = btrfs_search_slot(trans, extent_root,
3801                                                 &key, path, -1, 1);
3802                         if (ret) {
3803                                 printk(KERN_ERR "umm, got %d back from search"
3804                                        ", was looking for %llu\n", ret,
3805                                        (unsigned long long)bytenr);
3806                                 btrfs_print_leaf(extent_root, path->nodes[0]);
3807                         }
3808                         BUG_ON(ret);
3809                         extent_slot = path->slots[0];
3810                 }
3811         } else {
3812                 btrfs_print_leaf(extent_root, path->nodes[0]);
3813                 WARN_ON(1);
3814                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
3815                        "parent %llu root %llu  owner %llu offset %llu\n",
3816                        (unsigned long long)bytenr,
3817                        (unsigned long long)parent,
3818                        (unsigned long long)root_objectid,
3819                        (unsigned long long)owner_objectid,
3820                        (unsigned long long)owner_offset);
3821         }
3822
3823         leaf = path->nodes[0];
3824         item_size = btrfs_item_size_nr(leaf, extent_slot);
3825 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3826         if (item_size < sizeof(*ei)) {
3827                 BUG_ON(found_extent || extent_slot != path->slots[0]);
3828                 ret = convert_extent_item_v0(trans, extent_root, path,
3829                                              owner_objectid, 0);
3830                 BUG_ON(ret < 0);
3831
3832                 btrfs_release_path(extent_root, path);
3833                 path->leave_spinning = 1;
3834
3835                 key.objectid = bytenr;
3836                 key.type = BTRFS_EXTENT_ITEM_KEY;
3837                 key.offset = num_bytes;
3838
3839                 ret = btrfs_search_slot(trans, extent_root, &key, path,
3840                                         -1, 1);
3841                 if (ret) {
3842                         printk(KERN_ERR "umm, got %d back from search"
3843                                ", was looking for %llu\n", ret,
3844                                (unsigned long long)bytenr);
3845                         btrfs_print_leaf(extent_root, path->nodes[0]);
3846                 }
3847                 BUG_ON(ret);
3848                 extent_slot = path->slots[0];
3849                 leaf = path->nodes[0];
3850                 item_size = btrfs_item_size_nr(leaf, extent_slot);
3851         }
3852 #endif
3853         BUG_ON(item_size < sizeof(*ei));
3854         ei = btrfs_item_ptr(leaf, extent_slot,
3855                             struct btrfs_extent_item);
3856         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
3857                 struct btrfs_tree_block_info *bi;
3858                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
3859                 bi = (struct btrfs_tree_block_info *)(ei + 1);
3860                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
3861         }
3862
3863         refs = btrfs_extent_refs(leaf, ei);
3864         BUG_ON(refs < refs_to_drop);
3865         refs -= refs_to_drop;
3866
3867         if (refs > 0) {
3868                 if (extent_op)
3869                         __run_delayed_extent_op(extent_op, leaf, ei);
3870                 /*
3871                  * In the case of inline back ref, reference count will
3872                  * be updated by remove_extent_backref
3873                  */
3874                 if (iref) {
3875                         BUG_ON(!found_extent);
3876                 } else {
3877                         btrfs_set_extent_refs(leaf, ei, refs);
3878                         btrfs_mark_buffer_dirty(leaf);
3879                 }
3880                 if (found_extent) {
3881                         ret = remove_extent_backref(trans, extent_root, path,
3882                                                     iref, refs_to_drop,
3883                                                     is_data);
3884                         BUG_ON(ret);
3885                 }
3886         } else {
3887                 int mark_free = 0;
3888                 struct extent_buffer *must_clean = NULL;
3889
3890                 if (found_extent) {
3891                         BUG_ON(is_data && refs_to_drop !=
3892                                extent_data_ref_count(root, path, iref));
3893                         if (iref) {
3894                                 BUG_ON(path->slots[0] != extent_slot);
3895                         } else {
3896                                 BUG_ON(path->slots[0] != extent_slot + 1);
3897                                 path->slots[0] = extent_slot;
3898                                 num_to_del = 2;
3899                         }
3900                 }
3901
3902                 ret = pin_down_bytes(trans, root, path, bytenr,
3903                                      num_bytes, is_data, 0, &must_clean);
3904                 if (ret > 0)
3905                         mark_free = 1;
3906                 BUG_ON(ret < 0);
3907                 /*
3908                  * it is going to be very rare for someone to be waiting
3909                  * on the block we're freeing.  del_items might need to
3910                  * schedule, so rather than get fancy, just force it
3911                  * to blocking here
3912                  */
3913                 if (must_clean)
3914                         btrfs_set_lock_blocking(must_clean);
3915
3916                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
3917                                       num_to_del);
3918                 BUG_ON(ret);
3919                 btrfs_release_path(extent_root, path);
3920
3921                 if (must_clean) {
3922                         clean_tree_block(NULL, root, must_clean);
3923                         btrfs_tree_unlock(must_clean);
3924                         free_extent_buffer(must_clean);
3925                 }
3926
3927                 if (is_data) {
3928                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
3929                         BUG_ON(ret);
3930                 } else {
3931                         invalidate_mapping_pages(info->btree_inode->i_mapping,
3932                              bytenr >> PAGE_CACHE_SHIFT,
3933                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
3934                 }
3935
3936                 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
3937                                          mark_free);
3938                 BUG_ON(ret);
3939         }
3940         btrfs_free_path(path);
3941         return ret;
3942 }
3943
3944 /*
3945  * when we free an extent, it is possible (and likely) that we free the last
3946  * delayed ref for that extent as well.  This searches the delayed ref tree for
3947  * a given extent, and if there are no other delayed refs to be processed, it
3948  * removes it from the tree.
3949  */
3950 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
3951                                       struct btrfs_root *root, u64 bytenr)
3952 {
3953         struct btrfs_delayed_ref_head *head;
3954         struct btrfs_delayed_ref_root *delayed_refs;
3955         struct btrfs_delayed_ref_node *ref;
3956         struct rb_node *node;
3957         int ret;
3958
3959         delayed_refs = &trans->transaction->delayed_refs;
3960         spin_lock(&delayed_refs->lock);
3961         head = btrfs_find_delayed_ref_head(trans, bytenr);
3962         if (!head)
3963                 goto out;
3964
3965         node = rb_prev(&head->node.rb_node);
3966         if (!node)
3967                 goto out;
3968
3969         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
3970
3971         /* there are still entries for this ref, we can't drop it */
3972         if (ref->bytenr == bytenr)
3973                 goto out;
3974
3975         if (head->extent_op) {
3976                 if (!head->must_insert_reserved)
3977                         goto out;
3978                 kfree(head->extent_op);
3979                 head->extent_op = NULL;
3980         }
3981
3982         /*
3983          * waiting for the lock here would deadlock.  If someone else has it
3984          * locked they are already in the process of dropping it anyway
3985          */
3986         if (!mutex_trylock(&head->mutex))
3987                 goto out;
3988
3989         /*
3990          * at this point we have a head with no other entries.  Go
3991          * ahead and process it.
3992          */
3993         head->node.in_tree = 0;
3994         rb_erase(&head->node.rb_node, &delayed_refs->root);
3995
3996         delayed_refs->num_entries--;
3997
3998         /*
3999          * we don't take a ref on the node because we're removing it from the
4000          * tree, so we just steal the ref the tree was holding.
4001          */
4002         delayed_refs->num_heads--;
4003         if (list_empty(&head->cluster))
4004                 delayed_refs->num_heads_ready--;
4005
4006         list_del_init(&head->cluster);
4007         spin_unlock(&delayed_refs->lock);
4008
4009         ret = run_one_delayed_ref(trans, root->fs_info->tree_root,
4010                                   &head->node, head->extent_op,
4011                                   head->must_insert_reserved);
4012         BUG_ON(ret);
4013         btrfs_put_delayed_ref(&head->node);
4014         return 0;
4015 out:
4016         spin_unlock(&delayed_refs->lock);
4017         return 0;
4018 }
4019
4020 int btrfs_free_extent(struct btrfs_trans_handle *trans,
4021                       struct btrfs_root *root,
4022                       u64 bytenr, u64 num_bytes, u64 parent,
4023                       u64 root_objectid, u64 owner, u64 offset)
4024 {
4025         int ret;
4026
4027         /*
4028          * tree log blocks never actually go into the extent allocation
4029          * tree, just update pinning info and exit early.
4030          */
4031         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
4032                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
4033                 /* unlocks the pinned mutex */
4034                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
4035                 ret = 0;
4036         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
4037                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
4038                                         parent, root_objectid, (int)owner,
4039                                         BTRFS_DROP_DELAYED_REF, NULL);
4040                 BUG_ON(ret);
4041                 ret = check_ref_cleanup(trans, root, bytenr);
4042                 BUG_ON(ret);
4043         } else {
4044                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
4045                                         parent, root_objectid, owner,
4046                                         offset, BTRFS_DROP_DELAYED_REF, NULL);
4047                 BUG_ON(ret);
4048         }
4049         return ret;
4050 }
4051
4052 static u64 stripe_align(struct btrfs_root *root, u64 val)
4053 {
4054         u64 mask = ((u64)root->stripesize - 1);
4055         u64 ret = (val + mask) & ~mask;
4056         return ret;
4057 }
4058
4059 /*
4060  * when we wait for progress in the block group caching, its because
4061  * our allocation attempt failed at least once.  So, we must sleep
4062  * and let some progress happen before we try again.
4063  *
4064  * This function will sleep at least once waiting for new free space to
4065  * show up, and then it will check the block group free space numbers
4066  * for our min num_bytes.  Another option is to have it go ahead
4067  * and look in the rbtree for a free extent of a given size, but this
4068  * is a good start.
4069  */
4070 static noinline int
4071 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
4072                                 u64 num_bytes)
4073 {
4074         struct btrfs_caching_control *caching_ctl;
4075         DEFINE_WAIT(wait);
4076
4077         caching_ctl = get_caching_control(cache);
4078         if (!caching_ctl)
4079                 return 0;
4080
4081         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
4082                    (cache->free_space >= num_bytes));
4083
4084         put_caching_control(caching_ctl);
4085         return 0;
4086 }
4087
4088 static noinline int
4089 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
4090 {
4091         struct btrfs_caching_control *caching_ctl;
4092         DEFINE_WAIT(wait);
4093
4094         caching_ctl = get_caching_control(cache);
4095         if (!caching_ctl)
4096                 return 0;
4097
4098         wait_event(caching_ctl->wait, block_group_cache_done(cache));
4099
4100         put_caching_control(caching_ctl);
4101         return 0;
4102 }
4103
4104 enum btrfs_loop_type {
4105         LOOP_FIND_IDEAL = 0,
4106         LOOP_CACHING_NOWAIT = 1,
4107         LOOP_CACHING_WAIT = 2,
4108         LOOP_ALLOC_CHUNK = 3,
4109         LOOP_NO_EMPTY_SIZE = 4,
4110 };
4111
4112 /*
4113  * walks the btree of allocated extents and find a hole of a given size.
4114  * The key ins is changed to record the hole:
4115  * ins->objectid == block start
4116  * ins->flags = BTRFS_EXTENT_ITEM_KEY
4117  * ins->offset == number of blocks
4118  * Any available blocks before search_start are skipped.
4119  */
4120 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
4121                                      struct btrfs_root *orig_root,
4122                                      u64 num_bytes, u64 empty_size,
4123                                      u64 search_start, u64 search_end,
4124                                      u64 hint_byte, struct btrfs_key *ins,
4125                                      u64 exclude_start, u64 exclude_nr,
4126                                      int data)
4127 {
4128         int ret = 0;
4129         struct btrfs_root *root = orig_root->fs_info->extent_root;
4130         struct btrfs_free_cluster *last_ptr = NULL;
4131         struct btrfs_block_group_cache *block_group = NULL;
4132         int empty_cluster = 2 * 1024 * 1024;
4133         int allowed_chunk_alloc = 0;
4134         int done_chunk_alloc = 0;
4135         struct btrfs_space_info *space_info;
4136         int last_ptr_loop = 0;
4137         int loop = 0;
4138         bool found_uncached_bg = false;
4139         bool failed_cluster_refill = false;
4140         bool failed_alloc = false;
4141         u64 ideal_cache_percent = 0;
4142         u64 ideal_cache_offset = 0;
4143
4144         WARN_ON(num_bytes < root->sectorsize);
4145         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
4146         ins->objectid = 0;
4147         ins->offset = 0;
4148
4149         space_info = __find_space_info(root->fs_info, data);
4150
4151         if (orig_root->ref_cows || empty_size)
4152                 allowed_chunk_alloc = 1;
4153
4154         if (data & BTRFS_BLOCK_GROUP_METADATA) {
4155                 last_ptr = &root->fs_info->meta_alloc_cluster;
4156                 if (!btrfs_test_opt(root, SSD))
4157                         empty_cluster = 64 * 1024;
4158         }
4159
4160         if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD)) {
4161                 last_ptr = &root->fs_info->data_alloc_cluster;
4162         }
4163
4164         if (last_ptr) {
4165                 spin_lock(&last_ptr->lock);
4166                 if (last_ptr->block_group)
4167                         hint_byte = last_ptr->window_start;
4168                 spin_unlock(&last_ptr->lock);
4169         }
4170
4171         search_start = max(search_start, first_logical_byte(root, 0));
4172         search_start = max(search_start, hint_byte);
4173
4174         if (!last_ptr)
4175                 empty_cluster = 0;
4176
4177         if (search_start == hint_byte) {
4178 ideal_cache:
4179                 block_group = btrfs_lookup_block_group(root->fs_info,
4180                                                        search_start);
4181                 /*
4182                  * we don't want to use the block group if it doesn't match our
4183                  * allocation bits, or if its not cached.
4184                  *
4185                  * However if we are re-searching with an ideal block group
4186                  * picked out then we don't care that the block group is cached.
4187                  */
4188                 if (block_group && block_group_bits(block_group, data) &&
4189                     (block_group->cached != BTRFS_CACHE_NO ||
4190                      search_start == ideal_cache_offset)) {
4191                         down_read(&space_info->groups_sem);
4192                         if (list_empty(&block_group->list) ||
4193                             block_group->ro) {
4194                                 /*
4195                                  * someone is removing this block group,
4196                                  * we can't jump into the have_block_group
4197                                  * target because our list pointers are not
4198                                  * valid
4199                                  */
4200                                 btrfs_put_block_group(block_group);
4201                                 up_read(&space_info->groups_sem);
4202                         } else {
4203                                 goto have_block_group;
4204                         }
4205                 } else if (block_group) {
4206                         btrfs_put_block_group(block_group);
4207                 }
4208         }
4209 search:
4210         down_read(&space_info->groups_sem);
4211         list_for_each_entry(block_group, &space_info->block_groups, list) {
4212                 u64 offset;
4213                 int cached;
4214
4215                 atomic_inc(&block_group->count);
4216                 search_start = block_group->key.objectid;
4217
4218 have_block_group:
4219                 if (unlikely(block_group->cached == BTRFS_CACHE_NO)) {
4220                         u64 free_percent;
4221
4222                         free_percent = btrfs_block_group_used(&block_group->item);
4223                         free_percent *= 100;
4224                         free_percent = div64_u64(free_percent,
4225                                                  block_group->key.offset);
4226                         free_percent = 100 - free_percent;
4227                         if (free_percent > ideal_cache_percent &&
4228                             likely(!block_group->ro)) {
4229                                 ideal_cache_offset = block_group->key.objectid;
4230                                 ideal_cache_percent = free_percent;
4231                         }
4232
4233                         /*
4234                          * We only want to start kthread caching if we are at
4235                          * the point where we will wait for caching to make
4236                          * progress, or if our ideal search is over and we've
4237                          * found somebody to start caching.
4238                          */
4239                         if (loop > LOOP_CACHING_NOWAIT ||
4240                             (loop > LOOP_FIND_IDEAL &&
4241                              atomic_read(&space_info->caching_threads) < 2)) {
4242                                 ret = cache_block_group(block_group);
4243                                 BUG_ON(ret);
4244                         }
4245                         found_uncached_bg = true;
4246
4247                         /*
4248                          * If loop is set for cached only, try the next block
4249                          * group.
4250                          */
4251                         if (loop == LOOP_FIND_IDEAL)
4252                                 goto loop;
4253                 }
4254
4255                 cached = block_group_cache_done(block_group);
4256                 if (unlikely(!cached))
4257                         found_uncached_bg = true;
4258
4259                 if (unlikely(block_group->ro))
4260                         goto loop;
4261
4262                 /*
4263                  * Ok we want to try and use the cluster allocator, so lets look
4264                  * there, unless we are on LOOP_NO_EMPTY_SIZE, since we will
4265                  * have tried the cluster allocator plenty of times at this
4266                  * point and not have found anything, so we are likely way too
4267                  * fragmented for the clustering stuff to find anything, so lets
4268                  * just skip it and let the allocator find whatever block it can
4269                  * find
4270                  */
4271                 if (last_ptr && loop < LOOP_NO_EMPTY_SIZE) {
4272                         /*
4273                          * the refill lock keeps out other
4274                          * people trying to start a new cluster
4275                          */
4276                         spin_lock(&last_ptr->refill_lock);
4277                         if (last_ptr->block_group &&
4278                             (last_ptr->block_group->ro ||
4279                             !block_group_bits(last_ptr->block_group, data))) {
4280                                 offset = 0;
4281                                 goto refill_cluster;
4282                         }
4283
4284                         offset = btrfs_alloc_from_cluster(block_group, last_ptr,
4285                                                  num_bytes, search_start);
4286                         if (offset) {
4287                                 /* we have a block, we're done */
4288                                 spin_unlock(&last_ptr->refill_lock);
4289                                 goto checks;
4290                         }
4291
4292                         spin_lock(&last_ptr->lock);
4293                         /*
4294                          * whoops, this cluster doesn't actually point to
4295                          * this block group.  Get a ref on the block
4296                          * group is does point to and try again
4297                          */
4298                         if (!last_ptr_loop && last_ptr->block_group &&
4299                             last_ptr->block_group != block_group) {
4300
4301                                 btrfs_put_block_group(block_group);
4302                                 block_group = last_ptr->block_group;
4303                                 atomic_inc(&block_group->count);
4304                                 spin_unlock(&last_ptr->lock);
4305                                 spin_unlock(&last_ptr->refill_lock);
4306
4307                                 last_ptr_loop = 1;
4308                                 search_start = block_group->key.objectid;
4309                                 /*
4310                                  * we know this block group is properly
4311                                  * in the list because
4312                                  * btrfs_remove_block_group, drops the
4313                                  * cluster before it removes the block
4314                                  * group from the list
4315                                  */
4316                                 goto have_block_group;
4317                         }
4318                         spin_unlock(&last_ptr->lock);
4319 refill_cluster:
4320                         /*
4321                          * this cluster didn't work out, free it and
4322                          * start over
4323                          */
4324                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
4325
4326                         last_ptr_loop = 0;
4327
4328                         /* allocate a cluster in this block group */
4329                         ret = btrfs_find_space_cluster(trans, root,
4330                                                block_group, last_ptr,
4331                                                offset, num_bytes,
4332                                                empty_cluster + empty_size);
4333                         if (ret == 0) {
4334                                 /*
4335                                  * now pull our allocation out of this
4336                                  * cluster
4337                                  */
4338                                 offset = btrfs_alloc_from_cluster(block_group,
4339                                                   last_ptr, num_bytes,
4340                                                   search_start);
4341                                 if (offset) {
4342                                         /* we found one, proceed */
4343                                         spin_unlock(&last_ptr->refill_lock);
4344                                         goto checks;
4345                                 }
4346                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
4347                                    && !failed_cluster_refill) {
4348                                 spin_unlock(&last_ptr->refill_lock);
4349
4350                                 failed_cluster_refill = true;
4351                                 wait_block_group_cache_progress(block_group,
4352                                        num_bytes + empty_cluster + empty_size);
4353                                 goto have_block_group;
4354                         }
4355
4356                         /*
4357                          * at this point we either didn't find a cluster
4358                          * or we weren't able to allocate a block from our
4359                          * cluster.  Free the cluster we've been trying
4360                          * to use, and go to the next block group
4361                          */
4362                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
4363                         spin_unlock(&last_ptr->refill_lock);
4364                         goto loop;
4365                 }
4366
4367                 offset = btrfs_find_space_for_alloc(block_group, search_start,
4368                                                     num_bytes, empty_size);
4369                 /*
4370                  * If we didn't find a chunk, and we haven't failed on this
4371                  * block group before, and this block group is in the middle of
4372                  * caching and we are ok with waiting, then go ahead and wait
4373                  * for progress to be made, and set failed_alloc to true.
4374                  *
4375                  * If failed_alloc is true then we've already waited on this
4376                  * block group once and should move on to the next block group.
4377                  */
4378                 if (!offset && !failed_alloc && !cached &&
4379                     loop > LOOP_CACHING_NOWAIT) {
4380                         wait_block_group_cache_progress(block_group,
4381                                                 num_bytes + empty_size);
4382                         failed_alloc = true;
4383                         goto have_block_group;
4384                 } else if (!offset) {
4385                         goto loop;
4386                 }
4387 checks:
4388                 search_start = stripe_align(root, offset);
4389                 /* move on to the next group */
4390                 if (search_start + num_bytes >= search_end) {
4391                         btrfs_add_free_space(block_group, offset, num_bytes);
4392                         goto loop;
4393                 }
4394
4395                 /* move on to the next group */
4396                 if (search_start + num_bytes >
4397                     block_group->key.objectid + block_group->key.offset) {
4398                         btrfs_add_free_space(block_group, offset, num_bytes);
4399                         goto loop;
4400                 }
4401
4402                 if (exclude_nr > 0 &&
4403                     (search_start + num_bytes > exclude_start &&
4404                      search_start < exclude_start + exclude_nr)) {
4405                         search_start = exclude_start + exclude_nr;
4406
4407                         btrfs_add_free_space(block_group, offset, num_bytes);
4408                         /*
4409                          * if search_start is still in this block group
4410                          * then we just re-search this block group
4411                          */
4412                         if (search_start >= block_group->key.objectid &&
4413                             search_start < (block_group->key.objectid +
4414                                             block_group->key.offset))
4415                                 goto have_block_group;
4416                         goto loop;
4417                 }
4418
4419                 ins->objectid = search_start;
4420                 ins->offset = num_bytes;
4421
4422                 if (offset < search_start)
4423                         btrfs_add_free_space(block_group, offset,
4424                                              search_start - offset);
4425                 BUG_ON(offset > search_start);
4426
4427                 update_reserved_extents(block_group, num_bytes, 1);
4428
4429                 /* we are all good, lets return */
4430                 break;
4431 loop:
4432                 failed_cluster_refill = false;
4433                 failed_alloc = false;
4434                 btrfs_put_block_group(block_group);
4435         }
4436         up_read(&space_info->groups_sem);
4437
4438         /* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
4439          *                      for them to make caching progress.  Also
4440          *                      determine the best possible bg to cache
4441          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
4442          *                      caching kthreads as we move along
4443          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
4444          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
4445          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
4446          *                      again
4447          */
4448         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE &&
4449             (found_uncached_bg || empty_size || empty_cluster ||
4450              allowed_chunk_alloc)) {
4451                 if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
4452                         found_uncached_bg = false;
4453                         loop++;
4454                         if (!ideal_cache_percent &&
4455                             atomic_read(&space_info->caching_threads))
4456                                 goto search;
4457
4458                         /*
4459                          * 1 of the following 2 things have happened so far
4460                          *
4461                          * 1) We found an ideal block group for caching that
4462                          * is mostly full and will cache quickly, so we might
4463                          * as well wait for it.
4464                          *
4465                          * 2) We searched for cached only and we didn't find
4466                          * anything, and we didn't start any caching kthreads
4467                          * either, so chances are we will loop through and
4468                          * start a couple caching kthreads, and then come back
4469                          * around and just wait for them.  This will be slower
4470                          * because we will have 2 caching kthreads reading at
4471                          * the same time when we could have just started one
4472                          * and waited for it to get far enough to give us an
4473                          * allocation, so go ahead and go to the wait caching
4474                          * loop.
4475                          */
4476                         loop = LOOP_CACHING_WAIT;
4477                         search_start = ideal_cache_offset;
4478                         ideal_cache_percent = 0;
4479                         goto ideal_cache;
4480                 } else if (loop == LOOP_FIND_IDEAL) {
4481                         /*
4482                          * Didn't find a uncached bg, wait on anything we find
4483                          * next.
4484                          */
4485                         loop = LOOP_CACHING_WAIT;
4486                         goto search;
4487                 }
4488
4489                 if (loop < LOOP_CACHING_WAIT) {
4490                         loop++;
4491                         goto search;
4492                 }
4493
4494                 if (loop == LOOP_ALLOC_CHUNK) {
4495                         empty_size = 0;
4496                         empty_cluster = 0;
4497                 }
4498
4499                 if (allowed_chunk_alloc) {
4500                         ret = do_chunk_alloc(trans, root, num_bytes +
4501                                              2 * 1024 * 1024, data, 1);
4502                         allowed_chunk_alloc = 0;
4503                         done_chunk_alloc = 1;
4504                 } else if (!done_chunk_alloc) {
4505                         space_info->force_alloc = 1;
4506                 }
4507
4508                 if (loop < LOOP_NO_EMPTY_SIZE) {
4509                         loop++;
4510                         goto search;
4511                 }
4512                 ret = -ENOSPC;
4513         } else if (!ins->objectid) {
4514                 ret = -ENOSPC;
4515         }
4516
4517         /* we found what we needed */
4518         if (ins->objectid) {
4519                 if (!(data & BTRFS_BLOCK_GROUP_DATA))
4520                         trans->block_group = block_group->key.objectid;
4521
4522                 btrfs_put_block_group(block_group);
4523                 ret = 0;
4524         }
4525
4526         return ret;
4527 }
4528
4529 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
4530                             int dump_block_groups)
4531 {
4532         struct btrfs_block_group_cache *cache;
4533
4534         spin_lock(&info->lock);
4535         printk(KERN_INFO "space_info has %llu free, is %sfull\n",
4536                (unsigned long long)(info->total_bytes - info->bytes_used -
4537                                     info->bytes_pinned - info->bytes_reserved -
4538                                     info->bytes_super),
4539                (info->full) ? "" : "not ");
4540         printk(KERN_INFO "space_info total=%llu, pinned=%llu, delalloc=%llu,"
4541                " may_use=%llu, used=%llu, root=%llu, super=%llu, reserved=%llu"
4542                "\n",
4543                (unsigned long long)info->total_bytes,
4544                (unsigned long long)info->bytes_pinned,
4545                (unsigned long long)info->bytes_delalloc,
4546                (unsigned long long)info->bytes_may_use,
4547                (unsigned long long)info->bytes_used,
4548                (unsigned long long)info->bytes_root,
4549                (unsigned long long)info->bytes_super,
4550                (unsigned long long)info->bytes_reserved);
4551         spin_unlock(&info->lock);
4552
4553         if (!dump_block_groups)
4554                 return;
4555
4556         down_read(&info->groups_sem);
4557         list_for_each_entry(cache, &info->block_groups, list) {
4558                 spin_lock(&cache->lock);
4559                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
4560                        "%llu pinned %llu reserved\n",
4561                        (unsigned long long)cache->key.objectid,
4562                        (unsigned long long)cache->key.offset,
4563                        (unsigned long long)btrfs_block_group_used(&cache->item),
4564                        (unsigned long long)cache->pinned,
4565                        (unsigned long long)cache->reserved);
4566                 btrfs_dump_free_space(cache, bytes);
4567                 spin_unlock(&cache->lock);
4568         }
4569         up_read(&info->groups_sem);
4570 }
4571
4572 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
4573                          struct btrfs_root *root,
4574                          u64 num_bytes, u64 min_alloc_size,
4575                          u64 empty_size, u64 hint_byte,
4576                          u64 search_end, struct btrfs_key *ins,
4577                          u64 data)
4578 {
4579         int ret;
4580         u64 search_start = 0;
4581         struct btrfs_fs_info *info = root->fs_info;
4582
4583         data = btrfs_get_alloc_profile(root, data);
4584 again:
4585         /*
4586          * the only place that sets empty_size is btrfs_realloc_node, which
4587          * is not called recursively on allocations
4588          */
4589         if (empty_size || root->ref_cows) {
4590                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
4591                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4592                                      2 * 1024 * 1024,
4593                                      BTRFS_BLOCK_GROUP_METADATA |
4594                                      (info->metadata_alloc_profile &
4595                                       info->avail_metadata_alloc_bits), 0);
4596                 }
4597                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4598                                      num_bytes + 2 * 1024 * 1024, data, 0);
4599         }
4600
4601         WARN_ON(num_bytes < root->sectorsize);
4602         ret = find_free_extent(trans, root, num_bytes, empty_size,
4603                                search_start, search_end, hint_byte, ins,
4604                                trans->alloc_exclude_start,
4605                                trans->alloc_exclude_nr, data);
4606
4607         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
4608                 num_bytes = num_bytes >> 1;
4609                 num_bytes = num_bytes & ~(root->sectorsize - 1);
4610                 num_bytes = max(num_bytes, min_alloc_size);
4611                 do_chunk_alloc(trans, root->fs_info->extent_root,
4612                                num_bytes, data, 1);
4613                 goto again;
4614         }
4615         if (ret == -ENOSPC) {
4616                 struct btrfs_space_info *sinfo;
4617
4618                 sinfo = __find_space_info(root->fs_info, data);
4619                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
4620                        "wanted %llu\n", (unsigned long long)data,
4621                        (unsigned long long)num_bytes);
4622                 dump_space_info(sinfo, num_bytes, 1);
4623         }
4624
4625         return ret;
4626 }
4627
4628 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
4629 {
4630         struct btrfs_block_group_cache *cache;
4631         int ret = 0;
4632
4633         cache = btrfs_lookup_block_group(root->fs_info, start);
4634         if (!cache) {
4635                 printk(KERN_ERR "Unable to find block group for %llu\n",
4636                        (unsigned long long)start);
4637                 return -ENOSPC;
4638         }
4639
4640         ret = btrfs_discard_extent(root, start, len);
4641
4642         btrfs_add_free_space(cache, start, len);
4643         update_reserved_extents(cache, len, 0);
4644         btrfs_put_block_group(cache);
4645
4646         return ret;
4647 }
4648
4649 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4650                                       struct btrfs_root *root,
4651                                       u64 parent, u64 root_objectid,
4652                                       u64 flags, u64 owner, u64 offset,
4653                                       struct btrfs_key *ins, int ref_mod)
4654 {
4655         int ret;
4656         struct btrfs_fs_info *fs_info = root->fs_info;
4657         struct btrfs_extent_item *extent_item;
4658         struct btrfs_extent_inline_ref *iref;
4659         struct btrfs_path *path;
4660         struct extent_buffer *leaf;
4661         int type;
4662         u32 size;
4663
4664         if (parent > 0)
4665                 type = BTRFS_SHARED_DATA_REF_KEY;
4666         else
4667                 type = BTRFS_EXTENT_DATA_REF_KEY;
4668
4669         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
4670
4671         path = btrfs_alloc_path();
4672         BUG_ON(!path);
4673
4674         path->leave_spinning = 1;
4675         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
4676                                       ins, size);
4677         BUG_ON(ret);
4678
4679         leaf = path->nodes[0];
4680         extent_item = btrfs_item_ptr(leaf, path->slots[0],
4681                                      struct btrfs_extent_item);
4682         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
4683         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
4684         btrfs_set_extent_flags(leaf, extent_item,
4685                                flags | BTRFS_EXTENT_FLAG_DATA);
4686
4687         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4688         btrfs_set_extent_inline_ref_type(leaf, iref, type);
4689         if (parent > 0) {
4690                 struct btrfs_shared_data_ref *ref;
4691                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
4692                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
4693                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
4694         } else {
4695                 struct btrfs_extent_data_ref *ref;
4696                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
4697                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
4698                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
4699                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
4700                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
4701         }
4702
4703         btrfs_mark_buffer_dirty(path->nodes[0]);
4704         btrfs_free_path(path);
4705
4706         ret = update_block_group(trans, root, ins->objectid, ins->offset,
4707                                  1, 0);
4708         if (ret) {
4709                 printk(KERN_ERR "btrfs update block group failed for %llu "
4710                        "%llu\n", (unsigned long long)ins->objectid,
4711                        (unsigned long long)ins->offset);
4712                 BUG();
4713         }
4714         return ret;
4715 }
4716
4717 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
4718                                      struct btrfs_root *root,
4719                                      u64 parent, u64 root_objectid,
4720                                      u64 flags, struct btrfs_disk_key *key,
4721                                      int level, struct btrfs_key *ins)
4722 {
4723         int ret;
4724         struct btrfs_fs_info *fs_info = root->fs_info;
4725         struct btrfs_extent_item *extent_item;
4726         struct btrfs_tree_block_info *block_info;
4727         struct btrfs_extent_inline_ref *iref;
4728         struct btrfs_path *path;
4729         struct extent_buffer *leaf;
4730         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
4731
4732         path = btrfs_alloc_path();
4733         BUG_ON(!path);
4734
4735         path->leave_spinning = 1;
4736         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
4737                                       ins, size);
4738         BUG_ON(ret);
4739
4740         leaf = path->nodes[0];
4741         extent_item = btrfs_item_ptr(leaf, path->slots[0],
4742                                      struct btrfs_extent_item);
4743         btrfs_set_extent_refs(leaf, extent_item, 1);
4744         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
4745         btrfs_set_extent_flags(leaf, extent_item,
4746                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
4747         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
4748
4749         btrfs_set_tree_block_key(leaf, block_info, key);
4750         btrfs_set_tree_block_level(leaf, block_info, level);
4751
4752         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
4753         if (parent > 0) {
4754                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
4755                 btrfs_set_extent_inline_ref_type(leaf, iref,
4756                                                  BTRFS_SHARED_BLOCK_REF_KEY);
4757                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
4758         } else {
4759                 btrfs_set_extent_inline_ref_type(leaf, iref,
4760                                                  BTRFS_TREE_BLOCK_REF_KEY);
4761                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
4762         }
4763
4764         btrfs_mark_buffer_dirty(leaf);
4765         btrfs_free_path(path);
4766
4767         ret = update_block_group(trans, root, ins->objectid, ins->offset,
4768                                  1, 0);
4769         if (ret) {
4770                 printk(KERN_ERR "btrfs update block group failed for %llu "
4771                        "%llu\n", (unsigned long long)ins->objectid,
4772                        (unsigned long long)ins->offset);
4773                 BUG();
4774         }
4775         return ret;
4776 }
4777
4778 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4779                                      struct btrfs_root *root,
4780                                      u64 root_objectid, u64 owner,
4781                                      u64 offset, struct btrfs_key *ins)
4782 {
4783         int ret;
4784
4785         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
4786
4787         ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
4788                                          0, root_objectid, owner, offset,
4789                                          BTRFS_ADD_DELAYED_EXTENT, NULL);
4790         return ret;
4791 }
4792
4793 /*
4794  * this is used by the tree logging recovery code.  It records that
4795  * an extent has been allocated and makes sure to clear the free
4796  * space cache bits as well
4797  */
4798 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
4799                                    struct btrfs_root *root,
4800                                    u64 root_objectid, u64 owner, u64 offset,
4801                                    struct btrfs_key *ins)
4802 {
4803         int ret;
4804         struct btrfs_block_group_cache *block_group;
4805         struct btrfs_caching_control *caching_ctl;
4806         u64 start = ins->objectid;
4807         u64 num_bytes = ins->offset;
4808
4809         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
4810         cache_block_group(block_group);
4811         caching_ctl = get_caching_control(block_group);
4812
4813         if (!caching_ctl) {
4814                 BUG_ON(!block_group_cache_done(block_group));
4815                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
4816                 BUG_ON(ret);
4817         } else {
4818                 mutex_lock(&caching_ctl->mutex);
4819
4820                 if (start >= caching_ctl->progress) {
4821                         ret = add_excluded_extent(root, start, num_bytes);
4822                         BUG_ON(ret);
4823                 } else if (start + num_bytes <= caching_ctl->progress) {
4824                         ret = btrfs_remove_free_space(block_group,
4825                                                       start, num_bytes);
4826                         BUG_ON(ret);
4827                 } else {
4828                         num_bytes = caching_ctl->progress - start;
4829                         ret = btrfs_remove_free_space(block_group,
4830                                                       start, num_bytes);
4831                         BUG_ON(ret);
4832
4833                         start = caching_ctl->progress;
4834                         num_bytes = ins->objectid + ins->offset -
4835                                     caching_ctl->progress;
4836                         ret = add_excluded_extent(root, start, num_bytes);
4837                         BUG_ON(ret);
4838                 }
4839
4840                 mutex_unlock(&caching_ctl->mutex);
4841                 put_caching_control(caching_ctl);
4842         }
4843
4844         update_reserved_extents(block_group, ins->offset, 1);
4845         btrfs_put_block_group(block_group);
4846         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
4847                                          0, owner, offset, ins, 1);
4848         return ret;
4849 }
4850
4851 /*
4852  * finds a free extent and does all the dirty work required for allocation
4853  * returns the key for the extent through ins, and a tree buffer for
4854  * the first block of the extent through buf.
4855  *
4856  * returns 0 if everything worked, non-zero otherwise.
4857  */
4858 static int alloc_tree_block(struct btrfs_trans_handle *trans,
4859                             struct btrfs_root *root,
4860                             u64 num_bytes, u64 parent, u64 root_objectid,
4861                             struct btrfs_disk_key *key, int level,
4862                             u64 empty_size, u64 hint_byte, u64 search_end,
4863                             struct btrfs_key *ins)
4864 {
4865         int ret;
4866         u64 flags = 0;
4867
4868         ret = btrfs_reserve_extent(trans, root, num_bytes, num_bytes,
4869                                    empty_size, hint_byte, search_end,
4870                                    ins, 0);
4871         if (ret)
4872                 return ret;
4873
4874         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
4875                 if (parent == 0)
4876                         parent = ins->objectid;
4877                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
4878         } else
4879                 BUG_ON(parent > 0);
4880
4881         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
4882                 struct btrfs_delayed_extent_op *extent_op;
4883                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
4884                 BUG_ON(!extent_op);
4885                 if (key)
4886                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
4887                 else
4888                         memset(&extent_op->key, 0, sizeof(extent_op->key));
4889                 extent_op->flags_to_set = flags;
4890                 extent_op->update_key = 1;
4891                 extent_op->update_flags = 1;
4892                 extent_op->is_data = 0;
4893
4894                 ret = btrfs_add_delayed_tree_ref(trans, ins->objectid,
4895                                         ins->offset, parent, root_objectid,
4896                                         level, BTRFS_ADD_DELAYED_EXTENT,
4897                                         extent_op);
4898                 BUG_ON(ret);
4899         }
4900         return ret;
4901 }
4902
4903 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
4904                                             struct btrfs_root *root,
4905                                             u64 bytenr, u32 blocksize,
4906                                             int level)
4907 {
4908         struct extent_buffer *buf;
4909
4910         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
4911         if (!buf)
4912                 return ERR_PTR(-ENOMEM);
4913         btrfs_set_header_generation(buf, trans->transid);
4914         btrfs_set_buffer_lockdep_class(buf, level);
4915         btrfs_tree_lock(buf);
4916         clean_tree_block(trans, root, buf);
4917
4918         btrfs_set_lock_blocking(buf);
4919         btrfs_set_buffer_uptodate(buf);
4920
4921         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
4922                 /*
4923                  * we allow two log transactions at a time, use different
4924                  * EXENT bit to differentiate dirty pages.
4925                  */
4926                 if (root->log_transid % 2 == 0)
4927                         set_extent_dirty(&root->dirty_log_pages, buf->start,
4928                                         buf->start + buf->len - 1, GFP_NOFS);
4929                 else
4930                         set_extent_new(&root->dirty_log_pages, buf->start,
4931                                         buf->start + buf->len - 1, GFP_NOFS);
4932         } else {
4933                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
4934                          buf->start + buf->len - 1, GFP_NOFS);
4935         }
4936         trans->blocks_used++;
4937         /* this returns a buffer locked for blocking */
4938         return buf;
4939 }
4940
4941 /*
4942  * helper function to allocate a block for a given tree
4943  * returns the tree buffer or NULL.
4944  */
4945 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
4946                                         struct btrfs_root *root, u32 blocksize,
4947                                         u64 parent, u64 root_objectid,
4948                                         struct btrfs_disk_key *key, int level,
4949                                         u64 hint, u64 empty_size)
4950 {
4951         struct btrfs_key ins;
4952         int ret;
4953         struct extent_buffer *buf;
4954
4955         ret = alloc_tree_block(trans, root, blocksize, parent, root_objectid,
4956                                key, level, empty_size, hint, (u64)-1, &ins);
4957         if (ret) {
4958                 BUG_ON(ret > 0);
4959                 return ERR_PTR(ret);
4960         }
4961
4962         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
4963                                     blocksize, level);
4964         return buf;
4965 }
4966
4967 struct walk_control {
4968         u64 refs[BTRFS_MAX_LEVEL];
4969         u64 flags[BTRFS_MAX_LEVEL];
4970         struct btrfs_key update_progress;
4971         int stage;
4972         int level;
4973         int shared_level;
4974         int update_ref;
4975         int keep_locks;
4976         int reada_slot;
4977         int reada_count;
4978 };
4979
4980 #define DROP_REFERENCE  1
4981 #define UPDATE_BACKREF  2
4982
4983 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
4984                                      struct btrfs_root *root,
4985                                      struct walk_control *wc,
4986                                      struct btrfs_path *path)
4987 {
4988         u64 bytenr;
4989         u64 generation;
4990         u64 refs;
4991         u64 flags;
4992         u64 last = 0;
4993         u32 nritems;
4994         u32 blocksize;
4995         struct btrfs_key key;
4996         struct extent_buffer *eb;
4997         int ret;
4998         int slot;
4999         int nread = 0;
5000
5001         if (path->slots[wc->level] < wc->reada_slot) {
5002                 wc->reada_count = wc->reada_count * 2 / 3;
5003                 wc->reada_count = max(wc->reada_count, 2);
5004         } else {
5005                 wc->reada_count = wc->reada_count * 3 / 2;
5006                 wc->reada_count = min_t(int, wc->reada_count,
5007                                         BTRFS_NODEPTRS_PER_BLOCK(root));
5008         }
5009
5010         eb = path->nodes[wc->level];
5011         nritems = btrfs_header_nritems(eb);
5012         blocksize = btrfs_level_size(root, wc->level - 1);
5013
5014         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
5015                 if (nread >= wc->reada_count)
5016                         break;
5017
5018                 cond_resched();
5019                 bytenr = btrfs_node_blockptr(eb, slot);
5020                 generation = btrfs_node_ptr_generation(eb, slot);
5021
5022                 if (slot == path->slots[wc->level])
5023                         goto reada;
5024
5025                 if (wc->stage == UPDATE_BACKREF &&
5026                     generation <= root->root_key.offset)
5027                         continue;
5028
5029                 /* We don't lock the tree block, it's OK to be racy here */
5030                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
5031                                                &refs, &flags);
5032                 BUG_ON(ret);
5033                 BUG_ON(refs == 0);
5034
5035                 if (wc->stage == DROP_REFERENCE) {
5036                         if (refs == 1)
5037                                 goto reada;
5038
5039                         if (wc->level == 1 &&
5040                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5041                                 continue;
5042                         if (!wc->update_ref ||
5043                             generation <= root->root_key.offset)
5044                                 continue;
5045                         btrfs_node_key_to_cpu(eb, &key, slot);
5046                         ret = btrfs_comp_cpu_keys(&key,
5047                                                   &wc->update_progress);
5048                         if (ret < 0)
5049                                 continue;
5050                 } else {
5051                         if (wc->level == 1 &&
5052                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5053                                 continue;
5054                 }
5055 reada:
5056                 ret = readahead_tree_block(root, bytenr, blocksize,
5057                                            generation);
5058                 if (ret)
5059                         break;
5060                 last = bytenr + blocksize;
5061                 nread++;
5062         }
5063         wc->reada_slot = slot;
5064 }
5065
5066 /*
5067  * hepler to process tree block while walking down the tree.
5068  *
5069  * when wc->stage == UPDATE_BACKREF, this function updates
5070  * back refs for pointers in the block.
5071  *
5072  * NOTE: return value 1 means we should stop walking down.
5073  */
5074 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
5075                                    struct btrfs_root *root,
5076                                    struct btrfs_path *path,
5077                                    struct walk_control *wc, int lookup_info)
5078 {
5079         int level = wc->level;
5080         struct extent_buffer *eb = path->nodes[level];
5081         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5082         int ret;
5083
5084         if (wc->stage == UPDATE_BACKREF &&
5085             btrfs_header_owner(eb) != root->root_key.objectid)
5086                 return 1;
5087
5088         /*
5089          * when reference count of tree block is 1, it won't increase
5090          * again. once full backref flag is set, we never clear it.
5091          */
5092         if (lookup_info &&
5093             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
5094              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
5095                 BUG_ON(!path->locks[level]);
5096                 ret = btrfs_lookup_extent_info(trans, root,
5097                                                eb->start, eb->len,
5098                                                &wc->refs[level],
5099                                                &wc->flags[level]);
5100                 BUG_ON(ret);
5101                 BUG_ON(wc->refs[level] == 0);
5102         }
5103
5104         if (wc->stage == DROP_REFERENCE) {
5105                 if (wc->refs[level] > 1)
5106                         return 1;
5107
5108                 if (path->locks[level] && !wc->keep_locks) {
5109                         btrfs_tree_unlock(eb);
5110                         path->locks[level] = 0;
5111                 }
5112                 return 0;
5113         }
5114
5115         /* wc->stage == UPDATE_BACKREF */
5116         if (!(wc->flags[level] & flag)) {
5117                 BUG_ON(!path->locks[level]);
5118                 ret = btrfs_inc_ref(trans, root, eb, 1);
5119                 BUG_ON(ret);
5120                 ret = btrfs_dec_ref(trans, root, eb, 0);
5121                 BUG_ON(ret);
5122                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
5123                                                   eb->len, flag, 0);
5124                 BUG_ON(ret);
5125                 wc->flags[level] |= flag;
5126         }
5127
5128         /*
5129          * the block is shared by multiple trees, so it's not good to
5130          * keep the tree lock
5131          */
5132         if (path->locks[level] && level > 0) {
5133                 btrfs_tree_unlock(eb);
5134                 path->locks[level] = 0;
5135         }
5136         return 0;
5137 }
5138
5139 /*
5140  * hepler to process tree block pointer.
5141  *
5142  * when wc->stage == DROP_REFERENCE, this function checks
5143  * reference count of the block pointed to. if the block
5144  * is shared and we need update back refs for the subtree
5145  * rooted at the block, this function changes wc->stage to
5146  * UPDATE_BACKREF. if the block is shared and there is no
5147  * need to update back, this function drops the reference
5148  * to the block.
5149  *
5150  * NOTE: return value 1 means we should stop walking down.
5151  */
5152 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
5153                                  struct btrfs_root *root,
5154                                  struct btrfs_path *path,
5155                                  struct walk_control *wc, int *lookup_info)
5156 {
5157         u64 bytenr;
5158         u64 generation;
5159         u64 parent;
5160         u32 blocksize;
5161         struct btrfs_key key;
5162         struct extent_buffer *next;
5163         int level = wc->level;
5164         int reada = 0;
5165         int ret = 0;
5166
5167         generation = btrfs_node_ptr_generation(path->nodes[level],
5168                                                path->slots[level]);
5169         /*
5170          * if the lower level block was created before the snapshot
5171          * was created, we know there is no need to update back refs
5172          * for the subtree
5173          */
5174         if (wc->stage == UPDATE_BACKREF &&
5175             generation <= root->root_key.offset) {
5176                 *lookup_info = 1;
5177                 return 1;
5178         }
5179
5180         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
5181         blocksize = btrfs_level_size(root, level - 1);
5182
5183         next = btrfs_find_tree_block(root, bytenr, blocksize);
5184         if (!next) {
5185                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
5186                 reada = 1;
5187         }
5188         btrfs_tree_lock(next);
5189         btrfs_set_lock_blocking(next);
5190
5191         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
5192                                        &wc->refs[level - 1],
5193                                        &wc->flags[level - 1]);
5194         BUG_ON(ret);
5195         BUG_ON(wc->refs[level - 1] == 0);
5196         *lookup_info = 0;
5197
5198         if (wc->stage == DROP_REFERENCE) {
5199                 if (wc->refs[level - 1] > 1) {
5200                         if (level == 1 &&
5201                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5202                                 goto skip;
5203
5204                         if (!wc->update_ref ||
5205                             generation <= root->root_key.offset)
5206                                 goto skip;
5207
5208                         btrfs_node_key_to_cpu(path->nodes[level], &key,
5209                                               path->slots[level]);
5210                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
5211                         if (ret < 0)
5212                                 goto skip;
5213
5214                         wc->stage = UPDATE_BACKREF;
5215                         wc->shared_level = level - 1;
5216                 }
5217         } else {
5218                 if (level == 1 &&
5219                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5220                         goto skip;
5221         }
5222
5223         if (!btrfs_buffer_uptodate(next, generation)) {
5224                 btrfs_tree_unlock(next);
5225                 free_extent_buffer(next);
5226                 next = NULL;
5227                 *lookup_info = 1;
5228         }
5229
5230         if (!next) {
5231                 if (reada && level == 1)
5232                         reada_walk_down(trans, root, wc, path);
5233                 next = read_tree_block(root, bytenr, blocksize, generation);
5234                 btrfs_tree_lock(next);
5235                 btrfs_set_lock_blocking(next);
5236         }
5237
5238         level--;
5239         BUG_ON(level != btrfs_header_level(next));
5240         path->nodes[level] = next;
5241         path->slots[level] = 0;
5242         path->locks[level] = 1;
5243         wc->level = level;
5244         if (wc->level == 1)
5245                 wc->reada_slot = 0;
5246         return 0;
5247 skip:
5248         wc->refs[level - 1] = 0;
5249         wc->flags[level - 1] = 0;
5250         if (wc->stage == DROP_REFERENCE) {
5251                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
5252                         parent = path->nodes[level]->start;
5253                 } else {
5254                         BUG_ON(root->root_key.objectid !=
5255                                btrfs_header_owner(path->nodes[level]));
5256                         parent = 0;
5257                 }
5258
5259                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
5260                                         root->root_key.objectid, level - 1, 0);
5261                 BUG_ON(ret);
5262         }
5263         btrfs_tree_unlock(next);
5264         free_extent_buffer(next);
5265         *lookup_info = 1;
5266         return 1;
5267 }
5268
5269 /*
5270  * hepler to process tree block while walking up the tree.
5271  *
5272  * when wc->stage == DROP_REFERENCE, this function drops
5273  * reference count on the block.
5274  *
5275  * when wc->stage == UPDATE_BACKREF, this function changes
5276  * wc->stage back to DROP_REFERENCE if we changed wc->stage
5277  * to UPDATE_BACKREF previously while processing the block.
5278  *
5279  * NOTE: return value 1 means we should stop walking up.
5280  */
5281 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
5282                                  struct btrfs_root *root,
5283                                  struct btrfs_path *path,
5284                                  struct walk_control *wc)
5285 {
5286         int ret = 0;
5287         int level = wc->level;
5288         struct extent_buffer *eb = path->nodes[level];
5289         u64 parent = 0;
5290
5291         if (wc->stage == UPDATE_BACKREF) {
5292                 BUG_ON(wc->shared_level < level);
5293                 if (level < wc->shared_level)
5294                         goto out;
5295
5296                 ret = find_next_key(path, level + 1, &wc->update_progress);
5297                 if (ret > 0)
5298                         wc->update_ref = 0;
5299
5300                 wc->stage = DROP_REFERENCE;
5301                 wc->shared_level = -1;
5302                 path->slots[level] = 0;
5303
5304                 /*
5305                  * check reference count again if the block isn't locked.
5306                  * we should start walking down the tree again if reference
5307                  * count is one.
5308                  */
5309                 if (!path->locks[level]) {
5310                         BUG_ON(level == 0);
5311                         btrfs_tree_lock(eb);
5312                         btrfs_set_lock_blocking(eb);
5313                         path->locks[level] = 1;
5314
5315                         ret = btrfs_lookup_extent_info(trans, root,
5316                                                        eb->start, eb->len,
5317                                                        &wc->refs[level],
5318                                                        &wc->flags[level]);
5319                         BUG_ON(ret);
5320                         BUG_ON(wc->refs[level] == 0);
5321                         if (wc->refs[level] == 1) {
5322                                 btrfs_tree_unlock(eb);
5323                                 path->locks[level] = 0;
5324                                 return 1;
5325                         }
5326                 }
5327         }
5328
5329         /* wc->stage == DROP_REFERENCE */
5330         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
5331
5332         if (wc->refs[level] == 1) {
5333                 if (level == 0) {
5334                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5335                                 ret = btrfs_dec_ref(trans, root, eb, 1);
5336                         else
5337                                 ret = btrfs_dec_ref(trans, root, eb, 0);
5338                         BUG_ON(ret);
5339                 }
5340                 /* make block locked assertion in clean_tree_block happy */
5341                 if (!path->locks[level] &&
5342                     btrfs_header_generation(eb) == trans->transid) {
5343                         btrfs_tree_lock(eb);
5344                         btrfs_set_lock_blocking(eb);
5345                         path->locks[level] = 1;
5346                 }
5347                 clean_tree_block(trans, root, eb);
5348         }
5349
5350         if (eb == root->node) {
5351                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5352                         parent = eb->start;
5353                 else
5354                         BUG_ON(root->root_key.objectid !=
5355                                btrfs_header_owner(eb));
5356         } else {
5357                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5358                         parent = path->nodes[level + 1]->start;
5359                 else
5360                         BUG_ON(root->root_key.objectid !=
5361                                btrfs_header_owner(path->nodes[level + 1]));
5362         }
5363
5364         ret = btrfs_free_extent(trans, root, eb->start, eb->len, parent,
5365                                 root->root_key.objectid, level, 0);
5366         BUG_ON(ret);
5367 out:
5368         wc->refs[level] = 0;
5369         wc->flags[level] = 0;
5370         return ret;
5371 }
5372
5373 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
5374                                    struct btrfs_root *root,
5375                                    struct btrfs_path *path,
5376                                    struct walk_control *wc)
5377 {
5378         int level = wc->level;
5379         int lookup_info = 1;
5380         int ret;
5381
5382         while (level >= 0) {
5383                 if (path->slots[level] >=
5384                     btrfs_header_nritems(path->nodes[level]))
5385                         break;
5386
5387                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
5388                 if (ret > 0)
5389                         break;
5390
5391                 if (level == 0)
5392                         break;
5393
5394                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
5395                 if (ret > 0) {
5396                         path->slots[level]++;
5397                         continue;
5398                 }
5399                 level = wc->level;
5400         }
5401         return 0;
5402 }
5403
5404 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
5405                                  struct btrfs_root *root,
5406                                  struct btrfs_path *path,
5407                                  struct walk_control *wc, int max_level)
5408 {
5409         int level = wc->level;
5410         int ret;
5411
5412         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
5413         while (level < max_level && path->nodes[level]) {
5414                 wc->level = level;
5415                 if (path->slots[level] + 1 <
5416                     btrfs_header_nritems(path->nodes[level])) {
5417                         path->slots[level]++;
5418                         return 0;
5419                 } else {
5420                         ret = walk_up_proc(trans, root, path, wc);
5421                         if (ret > 0)
5422                                 return 0;
5423
5424                         if (path->locks[level]) {
5425                                 btrfs_tree_unlock(path->nodes[level]);
5426                                 path->locks[level] = 0;
5427                         }
5428                         free_extent_buffer(path->nodes[level]);
5429                         path->nodes[level] = NULL;
5430                         level++;
5431                 }
5432         }
5433         return 1;
5434 }
5435
5436 /*
5437  * drop a subvolume tree.
5438  *
5439  * this function traverses the tree freeing any blocks that only
5440  * referenced by the tree.
5441  *
5442  * when a shared tree block is found. this function decreases its
5443  * reference count by one. if update_ref is true, this function
5444  * also make sure backrefs for the shared block and all lower level
5445  * blocks are properly updated.
5446  */
5447 int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref)
5448 {
5449         struct btrfs_path *path;
5450         struct btrfs_trans_handle *trans;
5451         struct btrfs_root *tree_root = root->fs_info->tree_root;
5452         struct btrfs_root_item *root_item = &root->root_item;
5453         struct walk_control *wc;
5454         struct btrfs_key key;
5455         int err = 0;
5456         int ret;
5457         int level;
5458
5459         path = btrfs_alloc_path();
5460         BUG_ON(!path);
5461
5462         wc = kzalloc(sizeof(*wc), GFP_NOFS);
5463         BUG_ON(!wc);
5464
5465         trans = btrfs_start_transaction(tree_root, 1);
5466
5467         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
5468                 level = btrfs_header_level(root->node);
5469                 path->nodes[level] = btrfs_lock_root_node(root);
5470                 btrfs_set_lock_blocking(path->nodes[level]);
5471                 path->slots[level] = 0;
5472                 path->locks[level] = 1;
5473                 memset(&wc->update_progress, 0,
5474                        sizeof(wc->update_progress));
5475         } else {
5476                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
5477                 memcpy(&wc->update_progress, &key,
5478                        sizeof(wc->update_progress));
5479
5480                 level = root_item->drop_level;
5481                 BUG_ON(level == 0);
5482                 path->lowest_level = level;
5483                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5484                 path->lowest_level = 0;
5485                 if (ret < 0) {
5486                         err = ret;
5487                         goto out;
5488                 }
5489                 WARN_ON(ret > 0);
5490
5491                 /*
5492                  * unlock our path, this is safe because only this
5493                  * function is allowed to delete this snapshot
5494                  */
5495                 btrfs_unlock_up_safe(path, 0);
5496
5497                 level = btrfs_header_level(root->node);
5498                 while (1) {
5499                         btrfs_tree_lock(path->nodes[level]);
5500                         btrfs_set_lock_blocking(path->nodes[level]);
5501
5502                         ret = btrfs_lookup_extent_info(trans, root,
5503                                                 path->nodes[level]->start,
5504                                                 path->nodes[level]->len,
5505                                                 &wc->refs[level],
5506                                                 &wc->flags[level]);
5507                         BUG_ON(ret);
5508                         BUG_ON(wc->refs[level] == 0);
5509
5510                         if (level == root_item->drop_level)
5511                                 break;
5512
5513                         btrfs_tree_unlock(path->nodes[level]);
5514                         WARN_ON(wc->refs[level] != 1);
5515                         level--;
5516                 }
5517         }
5518
5519         wc->level = level;
5520         wc->shared_level = -1;
5521         wc->stage = DROP_REFERENCE;
5522         wc->update_ref = update_ref;
5523         wc->keep_locks = 0;
5524         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
5525
5526         while (1) {
5527                 ret = walk_down_tree(trans, root, path, wc);
5528                 if (ret < 0) {
5529                         err = ret;
5530                         break;
5531                 }
5532
5533                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
5534                 if (ret < 0) {
5535                         err = ret;
5536                         break;
5537                 }
5538
5539                 if (ret > 0) {
5540                         BUG_ON(wc->stage != DROP_REFERENCE);
5541                         break;
5542                 }
5543
5544                 if (wc->stage == DROP_REFERENCE) {
5545                         level = wc->level;
5546                         btrfs_node_key(path->nodes[level],
5547                                        &root_item->drop_progress,
5548                                        path->slots[level]);
5549                         root_item->drop_level = level;
5550                 }
5551
5552                 BUG_ON(wc->level == 0);
5553                 if (trans->transaction->in_commit ||
5554                     trans->transaction->delayed_refs.flushing) {
5555                         ret = btrfs_update_root(trans, tree_root,
5556                                                 &root->root_key,
5557                                                 root_item);
5558                         BUG_ON(ret);
5559
5560                         btrfs_end_transaction(trans, tree_root);
5561                         trans = btrfs_start_transaction(tree_root, 1);
5562                 } else {
5563                         unsigned long update;
5564                         update = trans->delayed_ref_updates;
5565                         trans->delayed_ref_updates = 0;
5566                         if (update)
5567                                 btrfs_run_delayed_refs(trans, tree_root,
5568                                                        update);
5569                 }
5570         }
5571         btrfs_release_path(root, path);
5572         BUG_ON(err);
5573
5574         ret = btrfs_del_root(trans, tree_root, &root->root_key);
5575         BUG_ON(ret);
5576
5577         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
5578                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
5579                                            NULL, NULL);
5580                 BUG_ON(ret < 0);
5581                 if (ret > 0) {
5582                         ret = btrfs_del_orphan_item(trans, tree_root,
5583                                                     root->root_key.objectid);
5584                         BUG_ON(ret);
5585                 }
5586         }
5587
5588         if (root->in_radix) {
5589                 btrfs_free_fs_root(tree_root->fs_info, root);
5590         } else {
5591                 free_extent_buffer(root->node);
5592                 free_extent_buffer(root->commit_root);
5593                 kfree(root);
5594         }
5595 out:
5596         btrfs_end_transaction(trans, tree_root);
5597         kfree(wc);
5598         btrfs_free_path(path);
5599         return err;
5600 }
5601
5602 /*
5603  * drop subtree rooted at tree block 'node'.
5604  *
5605  * NOTE: this function will unlock and release tree block 'node'
5606  */
5607 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
5608                         struct btrfs_root *root,
5609                         struct extent_buffer *node,
5610                         struct extent_buffer *parent)
5611 {
5612         struct btrfs_path *path;
5613         struct walk_control *wc;
5614         int level;
5615         int parent_level;
5616         int ret = 0;
5617         int wret;
5618
5619         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
5620
5621         path = btrfs_alloc_path();
5622         BUG_ON(!path);
5623
5624         wc = kzalloc(sizeof(*wc), GFP_NOFS);
5625         BUG_ON(!wc);
5626
5627         btrfs_assert_tree_locked(parent);
5628         parent_level = btrfs_header_level(parent);
5629         extent_buffer_get(parent);
5630         path->nodes[parent_level] = parent;
5631         path->slots[parent_level] = btrfs_header_nritems(parent);
5632
5633         btrfs_assert_tree_locked(node);
5634         level = btrfs_header_level(node);
5635         path->nodes[level] = node;
5636         path->slots[level] = 0;
5637         path->locks[level] = 1;
5638
5639         wc->refs[parent_level] = 1;
5640         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5641         wc->level = level;
5642         wc->shared_level = -1;
5643         wc->stage = DROP_REFERENCE;
5644         wc->update_ref = 0;
5645         wc->keep_locks = 1;
5646         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
5647
5648         while (1) {
5649                 wret = walk_down_tree(trans, root, path, wc);
5650                 if (wret < 0) {
5651                         ret = wret;
5652                         break;
5653                 }
5654
5655                 wret = walk_up_tree(trans, root, path, wc, parent_level);
5656                 if (wret < 0)
5657                         ret = wret;
5658                 if (wret != 0)
5659                         break;
5660         }
5661
5662         kfree(wc);
5663         btrfs_free_path(path);
5664         return ret;
5665 }
5666
5667 #if 0
5668 static unsigned long calc_ra(unsigned long start, unsigned long last,
5669                              unsigned long nr)
5670 {
5671         return min(last, start + nr - 1);
5672 }
5673
5674 static noinline int relocate_inode_pages(struct inode *inode, u64 start,
5675                                          u64 len)
5676 {
5677         u64 page_start;
5678         u64 page_end;
5679         unsigned long first_index;
5680         unsigned long last_index;
5681         unsigned long i;
5682         struct page *page;
5683         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
5684         struct file_ra_state *ra;
5685         struct btrfs_ordered_extent *ordered;
5686         unsigned int total_read = 0;
5687         unsigned int total_dirty = 0;
5688         int ret = 0;
5689
5690         ra = kzalloc(sizeof(*ra), GFP_NOFS);
5691
5692         mutex_lock(&inode->i_mutex);
5693         first_index = start >> PAGE_CACHE_SHIFT;
5694         last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
5695
5696         /* make sure the dirty trick played by the caller work */
5697         ret = invalidate_inode_pages2_range(inode->i_mapping,
5698                                             first_index, last_index);
5699         if (ret)
5700                 goto out_unlock;
5701
5702         file_ra_state_init(ra, inode->i_mapping);
5703
5704         for (i = first_index ; i <= last_index; i++) {
5705                 if (total_read % ra->ra_pages == 0) {
5706                         btrfs_force_ra(inode->i_mapping, ra, NULL, i,
5707                                        calc_ra(i, last_index, ra->ra_pages));
5708                 }
5709                 total_read++;
5710 again:
5711                 if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
5712                         BUG_ON(1);
5713                 page = grab_cache_page(inode->i_mapping, i);
5714                 if (!page) {
5715                         ret = -ENOMEM;
5716                         goto out_unlock;
5717                 }
5718                 if (!PageUptodate(page)) {
5719                         btrfs_readpage(NULL, page);
5720                         lock_page(page);
5721                         if (!PageUptodate(page)) {
5722                                 unlock_page(page);
5723                                 page_cache_release(page);
5724                                 ret = -EIO;
5725                                 goto out_unlock;
5726                         }
5727                 }
5728                 wait_on_page_writeback(page);
5729
5730                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
5731                 page_end = page_start + PAGE_CACHE_SIZE - 1;
5732                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
5733
5734                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
5735                 if (ordered) {
5736                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
5737                         unlock_page(page);
5738                         page_cache_release(page);
5739                         btrfs_start_ordered_extent(inode, ordered, 1);
5740                         btrfs_put_ordered_extent(ordered);
5741                         goto again;
5742                 }
5743                 set_page_extent_mapped(page);
5744
5745                 if (i == first_index)
5746                         set_extent_bits(io_tree, page_start, page_end,
5747                                         EXTENT_BOUNDARY, GFP_NOFS);
5748                 btrfs_set_extent_delalloc(inode, page_start, page_end);
5749
5750                 set_page_dirty(page);
5751                 total_dirty++;
5752
5753                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
5754                 unlock_page(page);
5755                 page_cache_release(page);
5756         }
5757
5758 out_unlock:
5759         kfree(ra);
5760         mutex_unlock(&inode->i_mutex);
5761         balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
5762         return ret;
5763 }
5764
5765 static noinline int relocate_data_extent(struct inode *reloc_inode,
5766                                          struct btrfs_key *extent_key,
5767                                          u64 offset)
5768 {
5769         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
5770         struct extent_map_tree *em_tree = &BTRFS_I(reloc_inode)->extent_tree;
5771         struct extent_map *em;
5772         u64 start = extent_key->objectid - offset;
5773         u64 end = start + extent_key->offset - 1;
5774
5775         em = alloc_extent_map(GFP_NOFS);
5776         BUG_ON(!em || IS_ERR(em));
5777
5778         em->start = start;
5779         em->len = extent_key->offset;
5780         em->block_len = extent_key->offset;
5781         em->block_start = extent_key->objectid;
5782         em->bdev = root->fs_info->fs_devices->latest_bdev;
5783         set_bit(EXTENT_FLAG_PINNED, &em->flags);
5784
5785         /* setup extent map to cheat btrfs_readpage */
5786         lock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
5787         while (1) {
5788                 int ret;
5789                 write_lock(&em_tree->lock);
5790                 ret = add_extent_mapping(em_tree, em);
5791                 write_unlock(&em_tree->lock);
5792                 if (ret != -EEXIST) {
5793                         free_extent_map(em);
5794                         break;
5795                 }
5796                 btrfs_drop_extent_cache(reloc_inode, start, end, 0);
5797         }
5798         unlock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
5799
5800         return relocate_inode_pages(reloc_inode, start, extent_key->offset);
5801 }
5802
5803 struct btrfs_ref_path {
5804         u64 extent_start;
5805         u64 nodes[BTRFS_MAX_LEVEL];
5806         u64 root_objectid;
5807         u64 root_generation;
5808         u64 owner_objectid;
5809         u32 num_refs;
5810         int lowest_level;
5811         int current_level;
5812         int shared_level;
5813
5814         struct btrfs_key node_keys[BTRFS_MAX_LEVEL];
5815         u64 new_nodes[BTRFS_MAX_LEVEL];
5816 };
5817
5818 struct disk_extent {
5819         u64 ram_bytes;
5820         u64 disk_bytenr;
5821         u64 disk_num_bytes;
5822         u64 offset;
5823         u64 num_bytes;
5824         u8 compression;
5825         u8 encryption;
5826         u16 other_encoding;
5827 };
5828
5829 static int is_cowonly_root(u64 root_objectid)
5830 {
5831         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
5832             root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
5833             root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
5834             root_objectid == BTRFS_DEV_TREE_OBJECTID ||
5835             root_objectid == BTRFS_TREE_LOG_OBJECTID ||
5836             root_objectid == BTRFS_CSUM_TREE_OBJECTID)
5837                 return 1;
5838         return 0;
5839 }
5840
5841 static noinline int __next_ref_path(struct btrfs_trans_handle *trans,
5842                                     struct btrfs_root *extent_root,
5843                                     struct btrfs_ref_path *ref_path,
5844                                     int first_time)
5845 {
5846         struct extent_buffer *leaf;
5847         struct btrfs_path *path;
5848         struct btrfs_extent_ref *ref;
5849         struct btrfs_key key;
5850         struct btrfs_key found_key;
5851         u64 bytenr;
5852         u32 nritems;
5853         int level;
5854         int ret = 1;
5855
5856         path = btrfs_alloc_path();
5857         if (!path)
5858                 return -ENOMEM;
5859
5860         if (first_time) {
5861                 ref_path->lowest_level = -1;
5862                 ref_path->current_level = -1;
5863                 ref_path->shared_level = -1;
5864                 goto walk_up;
5865         }
5866 walk_down:
5867         level = ref_path->current_level - 1;
5868         while (level >= -1) {
5869                 u64 parent;
5870                 if (level < ref_path->lowest_level)
5871                         break;
5872
5873                 if (level >= 0)
5874                         bytenr = ref_path->nodes[level];
5875                 else
5876                         bytenr = ref_path->extent_start;
5877                 BUG_ON(bytenr == 0);
5878
5879                 parent = ref_path->nodes[level + 1];
5880                 ref_path->nodes[level + 1] = 0;
5881                 ref_path->current_level = level;
5882                 BUG_ON(parent == 0);
5883
5884                 key.objectid = bytenr;
5885                 key.offset = parent + 1;
5886                 key.type = BTRFS_EXTENT_REF_KEY;
5887
5888                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
5889                 if (ret < 0)
5890                         goto out;
5891                 BUG_ON(ret == 0);
5892
5893                 leaf = path->nodes[0];
5894                 nritems = btrfs_header_nritems(leaf);
5895                 if (path->slots[0] >= nritems) {
5896                         ret = btrfs_next_leaf(extent_root, path);
5897                         if (ret < 0)
5898                                 goto out;
5899                         if (ret > 0)
5900                                 goto next;
5901                         leaf = path->nodes[0];
5902                 }
5903
5904                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5905                 if (found_key.objectid == bytenr &&
5906                     found_key.type == BTRFS_EXTENT_REF_KEY) {
5907                         if (level < ref_path->shared_level)
5908                                 ref_path->shared_level = level;
5909                         goto found;
5910                 }
5911 next:
5912                 level--;
5913                 btrfs_release_path(extent_root, path);
5914                 cond_resched();
5915         }
5916         /* reached lowest level */
5917         ret = 1;
5918         goto out;
5919 walk_up:
5920         level = ref_path->current_level;
5921         while (level < BTRFS_MAX_LEVEL - 1) {
5922                 u64 ref_objectid;
5923
5924                 if (level >= 0)
5925                         bytenr = ref_path->nodes[level];
5926                 else
5927                         bytenr = ref_path->extent_start;
5928
5929                 BUG_ON(bytenr == 0);
5930
5931                 key.objectid = bytenr;
5932                 key.offset = 0;
5933                 key.type = BTRFS_EXTENT_REF_KEY;
5934
5935                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
5936                 if (ret < 0)
5937                         goto out;
5938
5939                 leaf = path->nodes[0];
5940                 nritems = btrfs_header_nritems(leaf);
5941                 if (path->slots[0] >= nritems) {
5942                         ret = btrfs_next_leaf(extent_root, path);
5943                         if (ret < 0)
5944                                 goto out;
5945                         if (ret > 0) {
5946                                 /* the extent was freed by someone */
5947                                 if (ref_path->lowest_level == level)
5948                                         goto out;
5949                                 btrfs_release_path(extent_root, path);
5950                                 goto walk_down;
5951                         }
5952                         leaf = path->nodes[0];
5953                 }
5954
5955                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5956                 if (found_key.objectid != bytenr ||
5957                                 found_key.type != BTRFS_EXTENT_REF_KEY) {
5958                         /* the extent was freed by someone */
5959                         if (ref_path->lowest_level == level) {
5960                                 ret = 1;
5961                                 goto out;
5962                         }
5963                         btrfs_release_path(extent_root, path);
5964                         goto walk_down;
5965                 }
5966 found:
5967                 ref = btrfs_item_ptr(leaf, path->slots[0],
5968                                 struct btrfs_extent_ref);
5969                 ref_objectid = btrfs_ref_objectid(leaf, ref);
5970                 if (ref_objectid < BTRFS_FIRST_FREE_OBJECTID) {
5971                         if (first_time) {
5972                                 level = (int)ref_objectid;
5973                                 BUG_ON(level >= BTRFS_MAX_LEVEL);
5974                                 ref_path->lowest_level = level;
5975                                 ref_path->current_level = level;
5976                                 ref_path->nodes[level] = bytenr;
5977                         } else {
5978                                 WARN_ON(ref_objectid != level);
5979                         }
5980                 } else {
5981                         WARN_ON(level != -1);
5982                 }
5983                 first_time = 0;
5984
5985                 if (ref_path->lowest_level == level) {
5986                         ref_path->owner_objectid = ref_objectid;
5987                         ref_path->num_refs = btrfs_ref_num_refs(leaf, ref);
5988                 }
5989
5990                 /*
5991                  * the block is tree root or the block isn't in reference
5992                  * counted tree.
5993                  */
5994                 if (found_key.objectid == found_key.offset ||
5995                     is_cowonly_root(btrfs_ref_root(leaf, ref))) {
5996                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
5997                         ref_path->root_generation =
5998                                 btrfs_ref_generation(leaf, ref);
5999                         if (level < 0) {
6000                                 /* special reference from the tree log */
6001                                 ref_path->nodes[0] = found_key.offset;
6002                                 ref_path->current_level = 0;
6003                         }
6004                         ret = 0;
6005                         goto out;
6006                 }
6007
6008                 level++;
6009                 BUG_ON(ref_path->nodes[level] != 0);
6010                 ref_path->nodes[level] = found_key.offset;
6011                 ref_path->current_level = level;
6012
6013                 /*
6014                  * the reference was created in the running transaction,
6015                  * no need to continue walking up.
6016                  */
6017                 if (btrfs_ref_generation(leaf, ref) == trans->transid) {
6018                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
6019                         ref_path->root_generation =
6020                                 btrfs_ref_generation(leaf, ref);
6021                         ret = 0;
6022                         goto out;
6023                 }
6024
6025                 btrfs_release_path(extent_root, path);
6026                 cond_resched();
6027         }
6028         /* reached max tree level, but no tree root found. */
6029         BUG();
6030 out:
6031         btrfs_free_path(path);
6032         return ret;
6033 }
6034
6035 static int btrfs_first_ref_path(struct btrfs_trans_handle *trans,
6036                                 struct btrfs_root *extent_root,
6037                                 struct btrfs_ref_path *ref_path,
6038                                 u64 extent_start)
6039 {
6040         memset(ref_path, 0, sizeof(*ref_path));
6041         ref_path->extent_start = extent_start;
6042
6043         return __next_ref_path(trans, extent_root, ref_path, 1);
6044 }
6045
6046 static int btrfs_next_ref_path(struct btrfs_trans_handle *trans,
6047                                struct btrfs_root *extent_root,
6048                                struct btrfs_ref_path *ref_path)
6049 {
6050         return __next_ref_path(trans, extent_root, ref_path, 0);
6051 }
6052
6053 static noinline int get_new_locations(struct inode *reloc_inode,
6054                                       struct btrfs_key *extent_key,
6055                                       u64 offset, int no_fragment,
6056                                       struct disk_extent **extents,
6057                                       int *nr_extents)
6058 {
6059         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
6060         struct btrfs_path *path;
6061         struct btrfs_file_extent_item *fi;
6062         struct extent_buffer *leaf;
6063         struct disk_extent *exts = *extents;
6064         struct btrfs_key found_key;
6065         u64 cur_pos;
6066         u64 last_byte;
6067         u32 nritems;
6068         int nr = 0;
6069         int max = *nr_extents;
6070         int ret;
6071
6072         WARN_ON(!no_fragment && *extents);
6073         if (!exts) {
6074                 max = 1;
6075                 exts = kmalloc(sizeof(*exts) * max, GFP_NOFS);
6076                 if (!exts)
6077                         return -ENOMEM;
6078         }
6079
6080         path = btrfs_alloc_path();
6081         BUG_ON(!path);
6082
6083         cur_pos = extent_key->objectid - offset;
6084         last_byte = extent_key->objectid + extent_key->offset;
6085         ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
6086                                        cur_pos, 0);
6087         if (ret < 0)
6088                 goto out;
6089         if (ret > 0) {
6090                 ret = -ENOENT;
6091                 goto out;
6092         }
6093
6094         while (1) {
6095                 leaf = path->nodes[0];
6096                 nritems = btrfs_header_nritems(leaf);
6097                 if (path->slots[0] >= nritems) {
6098                         ret = btrfs_next_leaf(root, path);
6099                         if (ret < 0)
6100                                 goto out;
6101                         if (ret > 0)
6102                                 break;
6103                         leaf = path->nodes[0];
6104                 }
6105
6106                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6107                 if (found_key.offset != cur_pos ||
6108                     found_key.type != BTRFS_EXTENT_DATA_KEY ||
6109                     found_key.objectid != reloc_inode->i_ino)
6110                         break;
6111
6112                 fi = btrfs_item_ptr(leaf, path->slots[0],
6113                                     struct btrfs_file_extent_item);
6114                 if (btrfs_file_extent_type(leaf, fi) !=
6115                     BTRFS_FILE_EXTENT_REG ||
6116                     btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
6117                         break;
6118
6119                 if (nr == max) {
6120                         struct disk_extent *old = exts;
6121                         max *= 2;
6122                         exts = kzalloc(sizeof(*exts) * max, GFP_NOFS);
6123                         memcpy(exts, old, sizeof(*exts) * nr);
6124                         if (old != *extents)
6125                                 kfree(old);
6126                 }
6127
6128                 exts[nr].disk_bytenr =
6129                         btrfs_file_extent_disk_bytenr(leaf, fi);
6130                 exts[nr].disk_num_bytes =
6131                         btrfs_file_extent_disk_num_bytes(leaf, fi);
6132                 exts[nr].offset = btrfs_file_extent_offset(leaf, fi);
6133                 exts[nr].num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
6134                 exts[nr].ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6135                 exts[nr].compression = btrfs_file_extent_compression(leaf, fi);
6136                 exts[nr].encryption = btrfs_file_extent_encryption(leaf, fi);
6137                 exts[nr].other_encoding = btrfs_file_extent_other_encoding(leaf,
6138                                                                            fi);
6139                 BUG_ON(exts[nr].offset > 0);
6140                 BUG_ON(exts[nr].compression || exts[nr].encryption);
6141                 BUG_ON(exts[nr].num_bytes != exts[nr].disk_num_bytes);
6142
6143                 cur_pos += exts[nr].num_bytes;
6144                 nr++;
6145
6146                 if (cur_pos + offset >= last_byte)
6147                         break;
6148
6149                 if (no_fragment) {
6150                         ret = 1;
6151                         goto out;
6152                 }
6153                 path->slots[0]++;
6154         }
6155
6156         BUG_ON(cur_pos + offset > last_byte);
6157         if (cur_pos + offset < last_byte) {
6158                 ret = -ENOENT;
6159                 goto out;
6160         }
6161         ret = 0;
6162 out:
6163         btrfs_free_path(path);
6164         if (ret) {
6165                 if (exts != *extents)
6166                         kfree(exts);
6167         } else {
6168                 *extents = exts;
6169                 *nr_extents = nr;
6170         }
6171         return ret;
6172 }
6173
6174 static noinline int replace_one_extent(struct btrfs_trans_handle *trans,
6175                                         struct btrfs_root *root,
6176                                         struct btrfs_path *path,
6177                                         struct btrfs_key *extent_key,
6178                                         struct btrfs_key *leaf_key,
6179                                         struct btrfs_ref_path *ref_path,
6180                                         struct disk_extent *new_extents,
6181                                         int nr_extents)
6182 {
6183         struct extent_buffer *leaf;
6184         struct btrfs_file_extent_item *fi;
6185         struct inode *inode = NULL;
6186         struct btrfs_key key;
6187         u64 lock_start = 0;
6188         u64 lock_end = 0;
6189         u64 num_bytes;
6190         u64 ext_offset;
6191         u64 search_end = (u64)-1;
6192         u32 nritems;
6193         int nr_scaned = 0;
6194         int extent_locked = 0;
6195         int extent_type;
6196         int ret;
6197
6198         memcpy(&key, leaf_key, sizeof(key));
6199         if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
6200                 if (key.objectid < ref_path->owner_objectid ||
6201                     (key.objectid == ref_path->owner_objectid &&
6202                      key.type < BTRFS_EXTENT_DATA_KEY)) {
6203                         key.objectid = ref_path->owner_objectid;
6204                         key.type = BTRFS_EXTENT_DATA_KEY;
6205                         key.offset = 0;
6206                 }
6207         }
6208
6209         while (1) {
6210                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
6211                 if (ret < 0)
6212                         goto out;
6213
6214                 leaf = path->nodes[0];
6215                 nritems = btrfs_header_nritems(leaf);
6216 next:
6217                 if (extent_locked && ret > 0) {
6218                         /*
6219                          * the file extent item was modified by someone
6220                          * before the extent got locked.
6221                          */
6222                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
6223                                       lock_end, GFP_NOFS);
6224                         extent_locked = 0;
6225                 }
6226
6227                 if (path->slots[0] >= nritems) {
6228                         if (++nr_scaned > 2)
6229                                 break;
6230
6231                         BUG_ON(extent_locked);
6232                         ret = btrfs_next_leaf(root, path);
6233                         if (ret < 0)
6234                                 goto out;
6235                         if (ret > 0)
6236                                 break;
6237                         leaf = path->nodes[0];
6238                         nritems = btrfs_header_nritems(leaf);
6239                 }
6240
6241                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
6242
6243                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
6244                         if ((key.objectid > ref_path->owner_objectid) ||
6245                             (key.objectid == ref_path->owner_objectid &&
6246                              key.type > BTRFS_EXTENT_DATA_KEY) ||
6247                             key.offset >= search_end)
6248                                 break;
6249                 }
6250
6251                 if (inode && key.objectid != inode->i_ino) {
6252                         BUG_ON(extent_locked);
6253                         btrfs_release_path(root, path);
6254                         mutex_unlock(&inode->i_mutex);
6255                         iput(inode);
6256                         inode = NULL;
6257                         continue;
6258                 }
6259
6260                 if (key.type != BTRFS_EXTENT_DATA_KEY) {
6261                         path->slots[0]++;
6262                         ret = 1;
6263                         goto next;
6264                 }
6265                 fi = btrfs_item_ptr(leaf, path->slots[0],
6266                                     struct btrfs_file_extent_item);
6267                 extent_type = btrfs_file_extent_type(leaf, fi);
6268                 if ((extent_type != BTRFS_FILE_EXTENT_REG &&
6269                      extent_type != BTRFS_FILE_EXTENT_PREALLOC) ||
6270                     (btrfs_file_extent_disk_bytenr(leaf, fi) !=
6271                      extent_key->objectid)) {
6272                         path->slots[0]++;
6273                         ret = 1;
6274                         goto next;
6275                 }
6276
6277                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
6278                 ext_offset = btrfs_file_extent_offset(leaf, fi);
6279
6280                 if (search_end == (u64)-1) {
6281                         search_end = key.offset - ext_offset +
6282                                 btrfs_file_extent_ram_bytes(leaf, fi);
6283                 }
6284
6285                 if (!extent_locked) {
6286                         lock_start = key.offset;
6287                         lock_end = lock_start + num_bytes - 1;
6288                 } else {
6289                         if (lock_start > key.offset ||
6290                             lock_end + 1 < key.offset + num_bytes) {
6291                                 unlock_extent(&BTRFS_I(inode)->io_tree,
6292                                               lock_start, lock_end, GFP_NOFS);
6293                                 extent_locked = 0;
6294                         }
6295                 }
6296
6297                 if (!inode) {
6298                         btrfs_release_path(root, path);
6299
6300                         inode = btrfs_iget_locked(root->fs_info->sb,
6301                                                   key.objectid, root);
6302                         if (inode->i_state & I_NEW) {
6303                                 BTRFS_I(inode)->root = root;
6304                                 BTRFS_I(inode)->location.objectid =
6305                                         key.objectid;
6306                                 BTRFS_I(inode)->location.type =
6307                                         BTRFS_INODE_ITEM_KEY;
6308                                 BTRFS_I(inode)->location.offset = 0;
6309                                 btrfs_read_locked_inode(inode);
6310                                 unlock_new_inode(inode);
6311                         }
6312                         /*
6313                          * some code call btrfs_commit_transaction while
6314                          * holding the i_mutex, so we can't use mutex_lock
6315                          * here.
6316                          */
6317                         if (is_bad_inode(inode) ||
6318                             !mutex_trylock(&inode->i_mutex)) {
6319                                 iput(inode);
6320                                 inode = NULL;
6321                                 key.offset = (u64)-1;
6322                                 goto skip;
6323                         }
6324                 }
6325
6326                 if (!extent_locked) {
6327                         struct btrfs_ordered_extent *ordered;
6328
6329                         btrfs_release_path(root, path);
6330
6331                         lock_extent(&BTRFS_I(inode)->io_tree, lock_start,
6332                                     lock_end, GFP_NOFS);
6333                         ordered = btrfs_lookup_first_ordered_extent(inode,
6334                                                                     lock_end);
6335                         if (ordered &&
6336                             ordered->file_offset <= lock_end &&
6337                             ordered->file_offset + ordered->len > lock_start) {
6338                                 unlock_extent(&BTRFS_I(inode)->io_tree,
6339                                               lock_start, lock_end, GFP_NOFS);
6340                                 btrfs_start_ordered_extent(inode, ordered, 1);
6341                                 btrfs_put_ordered_extent(ordered);
6342                                 key.offset += num_bytes;
6343                                 goto skip;
6344                         }
6345                         if (ordered)
6346                                 btrfs_put_ordered_extent(ordered);
6347
6348                         extent_locked = 1;
6349                         continue;
6350                 }
6351
6352                 if (nr_extents == 1) {
6353                         /* update extent pointer in place */
6354                         btrfs_set_file_extent_disk_bytenr(leaf, fi,
6355                                                 new_extents[0].disk_bytenr);
6356                         btrfs_set_file_extent_disk_num_bytes(leaf, fi,
6357                                                 new_extents[0].disk_num_bytes);
6358                         btrfs_mark_buffer_dirty(leaf);
6359
6360                         btrfs_drop_extent_cache(inode, key.offset,
6361                                                 key.offset + num_bytes - 1, 0);
6362
6363                         ret = btrfs_inc_extent_ref(trans, root,
6364                                                 new_extents[0].disk_bytenr,
6365                                                 new_extents[0].disk_num_bytes,
6366                                                 leaf->start,
6367                                                 root->root_key.objectid,
6368                                                 trans->transid,
6369                                                 key.objectid);
6370                         BUG_ON(ret);
6371
6372                         ret = btrfs_free_extent(trans, root,
6373                                                 extent_key->objectid,
6374                                                 extent_key->offset,
6375                                                 leaf->start,
6376                                                 btrfs_header_owner(leaf),
6377                                                 btrfs_header_generation(leaf),
6378                                                 key.objectid, 0);
6379                         BUG_ON(ret);
6380
6381                         btrfs_release_path(root, path);
6382                         key.offset += num_bytes;
6383                 } else {
6384                         BUG_ON(1);
6385 #if 0
6386                         u64 alloc_hint;
6387                         u64 extent_len;
6388                         int i;
6389                         /*
6390                          * drop old extent pointer at first, then insert the
6391                          * new pointers one bye one
6392                          */
6393                         btrfs_release_path(root, path);
6394                         ret = btrfs_drop_extents(trans, root, inode, key.offset,
6395                                                  key.offset + num_bytes,
6396                                                  key.offset, &alloc_hint);
6397                         BUG_ON(ret);
6398
6399                         for (i = 0; i < nr_extents; i++) {
6400                                 if (ext_offset >= new_extents[i].num_bytes) {
6401                                         ext_offset -= new_extents[i].num_bytes;
6402                                         continue;
6403                                 }
6404                                 extent_len = min(new_extents[i].num_bytes -
6405                                                  ext_offset, num_bytes);
6406
6407                                 ret = btrfs_insert_empty_item(trans, root,
6408                                                               path, &key,
6409                                                               sizeof(*fi));
6410                                 BUG_ON(ret);
6411
6412                                 leaf = path->nodes[0];
6413                                 fi = btrfs_item_ptr(leaf, path->slots[0],
6414                                                 struct btrfs_file_extent_item);
6415                                 btrfs_set_file_extent_generation(leaf, fi,
6416                                                         trans->transid);
6417                                 btrfs_set_file_extent_type(leaf, fi,
6418                                                         BTRFS_FILE_EXTENT_REG);
6419                                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
6420                                                 new_extents[i].disk_bytenr);
6421                                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
6422                                                 new_extents[i].disk_num_bytes);
6423                                 btrfs_set_file_extent_ram_bytes(leaf, fi,
6424                                                 new_extents[i].ram_bytes);
6425
6426                                 btrfs_set_file_extent_compression(leaf, fi,
6427                                                 new_extents[i].compression);
6428                                 btrfs_set_file_extent_encryption(leaf, fi,
6429                                                 new_extents[i].encryption);
6430                                 btrfs_set_file_extent_other_encoding(leaf, fi,
6431                                                 new_extents[i].other_encoding);
6432
6433                                 btrfs_set_file_extent_num_bytes(leaf, fi,
6434                                                         extent_len);
6435                                 ext_offset += new_extents[i].offset;
6436                                 btrfs_set_file_extent_offset(leaf, fi,
6437                                                         ext_offset);
6438                                 btrfs_mark_buffer_dirty(leaf);
6439
6440                                 btrfs_drop_extent_cache(inode, key.offset,
6441                                                 key.offset + extent_len - 1, 0);
6442
6443                                 ret = btrfs_inc_extent_ref(trans, root,
6444                                                 new_extents[i].disk_bytenr,
6445                                                 new_extents[i].disk_num_bytes,
6446                                                 leaf->start,
6447                                                 root->root_key.objectid,
6448                                                 trans->transid, key.objectid);
6449                                 BUG_ON(ret);
6450                                 btrfs_release_path(root, path);
6451
6452                                 inode_add_bytes(inode, extent_len);
6453
6454                                 ext_offset = 0;
6455                                 num_bytes -= extent_len;
6456                                 key.offset += extent_len;
6457
6458                                 if (num_bytes == 0)
6459                                         break;
6460                         }
6461                         BUG_ON(i >= nr_extents);
6462 #endif
6463                 }
6464
6465                 if (extent_locked) {
6466                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
6467                                       lock_end, GFP_NOFS);
6468                         extent_locked = 0;
6469                 }
6470 skip:
6471                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS &&
6472                     key.offset >= search_end)
6473                         break;
6474
6475                 cond_resched();
6476         }
6477         ret = 0;
6478 out:
6479         btrfs_release_path(root, path);
6480         if (inode) {
6481                 mutex_unlock(&inode->i_mutex);
6482                 if (extent_locked) {
6483                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
6484                                       lock_end, GFP_NOFS);
6485                 }
6486                 iput(inode);
6487         }
6488         return ret;
6489 }
6490
6491 int btrfs_reloc_tree_cache_ref(struct btrfs_trans_handle *trans,
6492                                struct btrfs_root *root,
6493                                struct extent_buffer *buf, u64 orig_start)
6494 {
6495         int level;
6496         int ret;
6497
6498         BUG_ON(btrfs_header_generation(buf) != trans->transid);
6499         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6500
6501         level = btrfs_header_level(buf);
6502         if (level == 0) {
6503                 struct btrfs_leaf_ref *ref;
6504                 struct btrfs_leaf_ref *orig_ref;
6505
6506                 orig_ref = btrfs_lookup_leaf_ref(root, orig_start);
6507                 if (!orig_ref)
6508                         return -ENOENT;
6509
6510                 ref = btrfs_alloc_leaf_ref(root, orig_ref->nritems);
6511                 if (!ref) {
6512                         btrfs_free_leaf_ref(root, orig_ref);
6513                         return -ENOMEM;
6514                 }
6515
6516                 ref->nritems = orig_ref->nritems;
6517                 memcpy(ref->extents, orig_ref->extents,
6518                         sizeof(ref->extents[0]) * ref->nritems);
6519
6520                 btrfs_free_leaf_ref(root, orig_ref);
6521
6522                 ref->root_gen = trans->transid;
6523                 ref->bytenr = buf->start;
6524                 ref->owner = btrfs_header_owner(buf);
6525                 ref->generation = btrfs_header_generation(buf);
6526
6527                 ret = btrfs_add_leaf_ref(root, ref, 0);
6528                 WARN_ON(ret);
6529                 btrfs_free_leaf_ref(root, ref);
6530         }
6531         return 0;
6532 }
6533
6534 static noinline int invalidate_extent_cache(struct btrfs_root *root,
6535                                         struct extent_buffer *leaf,
6536                                         struct btrfs_block_group_cache *group,
6537                                         struct btrfs_root *target_root)
6538 {
6539         struct btrfs_key key;
6540         struct inode *inode = NULL;
6541         struct btrfs_file_extent_item *fi;
6542         u64 num_bytes;
6543         u64 skip_objectid = 0;
6544         u32 nritems;
6545         u32 i;
6546
6547         nritems = btrfs_header_nritems(leaf);
6548         for (i = 0; i < nritems; i++) {
6549                 btrfs_item_key_to_cpu(leaf, &key, i);
6550                 if (key.objectid == skip_objectid ||
6551                     key.type != BTRFS_EXTENT_DATA_KEY)
6552                         continue;
6553                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
6554                 if (btrfs_file_extent_type(leaf, fi) ==
6555                     BTRFS_FILE_EXTENT_INLINE)
6556                         continue;
6557                 if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
6558                         continue;
6559                 if (!inode || inode->i_ino != key.objectid) {
6560                         iput(inode);
6561                         inode = btrfs_ilookup(target_root->fs_info->sb,
6562                                               key.objectid, target_root, 1);
6563                 }
6564                 if (!inode) {
6565                         skip_objectid = key.objectid;
6566                         continue;
6567                 }
6568                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
6569
6570                 lock_extent(&BTRFS_I(inode)->io_tree, key.offset,
6571                             key.offset + num_bytes - 1, GFP_NOFS);
6572                 btrfs_drop_extent_cache(inode, key.offset,
6573                                         key.offset + num_bytes - 1, 1);
6574                 unlock_extent(&BTRFS_I(inode)->io_tree, key.offset,
6575                               key.offset + num_bytes - 1, GFP_NOFS);
6576                 cond_resched();
6577         }
6578         iput(inode);
6579         return 0;
6580 }
6581
6582 static noinline int replace_extents_in_leaf(struct btrfs_trans_handle *trans,
6583                                         struct btrfs_root *root,
6584                                         struct extent_buffer *leaf,
6585                                         struct btrfs_block_group_cache *group,
6586                                         struct inode *reloc_inode)
6587 {
6588         struct btrfs_key key;
6589         struct btrfs_key extent_key;
6590         struct btrfs_file_extent_item *fi;
6591         struct btrfs_leaf_ref *ref;
6592         struct disk_extent *new_extent;
6593         u64 bytenr;
6594         u64 num_bytes;
6595         u32 nritems;
6596         u32 i;
6597         int ext_index;
6598         int nr_extent;
6599         int ret;
6600
6601         new_extent = kmalloc(sizeof(*new_extent), GFP_NOFS);
6602         BUG_ON(!new_extent);
6603
6604         ref = btrfs_lookup_leaf_ref(root, leaf->start);
6605         BUG_ON(!ref);
6606
6607         ext_index = -1;
6608         nritems = btrfs_header_nritems(leaf);
6609         for (i = 0; i < nritems; i++) {
6610                 btrfs_item_key_to_cpu(leaf, &key, i);
6611                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
6612                         continue;
6613                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
6614                 if (btrfs_file_extent_type(leaf, fi) ==
6615                     BTRFS_FILE_EXTENT_INLINE)
6616                         continue;
6617                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
6618                 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
6619                 if (bytenr == 0)
6620                         continue;
6621
6622                 ext_index++;
6623                 if (bytenr >= group->key.objectid + group->key.offset ||
6624                     bytenr + num_bytes <= group->key.objectid)
6625                         continue;
6626
6627                 extent_key.objectid = bytenr;
6628                 extent_key.offset = num_bytes;
6629                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
6630                 nr_extent = 1;
6631                 ret = get_new_locations(reloc_inode, &extent_key,
6632                                         group->key.objectid, 1,
6633                                         &new_extent, &nr_extent);
6634                 if (ret > 0)
6635                         continue;
6636                 BUG_ON(ret < 0);
6637
6638                 BUG_ON(ref->extents[ext_index].bytenr != bytenr);
6639                 BUG_ON(ref->extents[ext_index].num_bytes != num_bytes);
6640                 ref->extents[ext_index].bytenr = new_extent->disk_bytenr;
6641                 ref->extents[ext_index].num_bytes = new_extent->disk_num_bytes;
6642
6643                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
6644                                                 new_extent->disk_bytenr);
6645                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
6646                                                 new_extent->disk_num_bytes);
6647                 btrfs_mark_buffer_dirty(leaf);
6648
6649                 ret = btrfs_inc_extent_ref(trans, root,
6650                                         new_extent->disk_bytenr,
6651                                         new_extent->disk_num_bytes,
6652                                         leaf->start,
6653                                         root->root_key.objectid,
6654                                         trans->transid, key.objectid);
6655                 BUG_ON(ret);
6656
6657                 ret = btrfs_free_extent(trans, root,
6658                                         bytenr, num_bytes, leaf->start,
6659                                         btrfs_header_owner(leaf),
6660                                         btrfs_header_generation(leaf),
6661                                         key.objectid, 0);
6662                 BUG_ON(ret);
6663                 cond_resched();
6664         }
6665         kfree(new_extent);
6666         BUG_ON(ext_index + 1 != ref->nritems);
6667         btrfs_free_leaf_ref(root, ref);
6668         return 0;
6669 }
6670
6671 int btrfs_free_reloc_root(struct btrfs_trans_handle *trans,
6672                           struct btrfs_root *root)
6673 {
6674         struct btrfs_root *reloc_root;
6675         int ret;
6676
6677         if (root->reloc_root) {
6678                 reloc_root = root->reloc_root;
6679                 root->reloc_root = NULL;
6680                 list_add(&reloc_root->dead_list,
6681                          &root->fs_info->dead_reloc_roots);
6682
6683                 btrfs_set_root_bytenr(&reloc_root->root_item,
6684                                       reloc_root->node->start);
6685                 btrfs_set_root_level(&root->root_item,
6686                                      btrfs_header_level(reloc_root->node));
6687                 memset(&reloc_root->root_item.drop_progress, 0,
6688                         sizeof(struct btrfs_disk_key));
6689                 reloc_root->root_item.drop_level = 0;
6690
6691                 ret = btrfs_update_root(trans, root->fs_info->tree_root,
6692                                         &reloc_root->root_key,
6693                                         &reloc_root->root_item);
6694                 BUG_ON(ret);
6695         }
6696         return 0;
6697 }
6698
6699 int btrfs_drop_dead_reloc_roots(struct btrfs_root *root)
6700 {
6701         struct btrfs_trans_handle *trans;
6702         struct btrfs_root *reloc_root;
6703         struct btrfs_root *prev_root = NULL;
6704         struct list_head dead_roots;
6705         int ret;
6706         unsigned long nr;
6707
6708         INIT_LIST_HEAD(&dead_roots);
6709         list_splice_init(&root->fs_info->dead_reloc_roots, &dead_roots);
6710
6711         while (!list_empty(&dead_roots)) {
6712                 reloc_root = list_entry(dead_roots.prev,
6713                                         struct btrfs_root, dead_list);
6714                 list_del_init(&reloc_root->dead_list);
6715
6716                 BUG_ON(reloc_root->commit_root != NULL);
6717                 while (1) {
6718                         trans = btrfs_join_transaction(root, 1);
6719                         BUG_ON(!trans);
6720
6721                         mutex_lock(&root->fs_info->drop_mutex);
6722                         ret = btrfs_drop_snapshot(trans, reloc_root);
6723                         if (ret != -EAGAIN)
6724                                 break;
6725                         mutex_unlock(&root->fs_info->drop_mutex);
6726
6727                         nr = trans->blocks_used;
6728                         ret = btrfs_end_transaction(trans, root);
6729                         BUG_ON(ret);
6730                         btrfs_btree_balance_dirty(root, nr);
6731                 }
6732
6733                 free_extent_buffer(reloc_root->node);
6734
6735                 ret = btrfs_del_root(trans, root->fs_info->tree_root,
6736                                      &reloc_root->root_key);
6737                 BUG_ON(ret);
6738                 mutex_unlock(&root->fs_info->drop_mutex);
6739
6740                 nr = trans->blocks_used;
6741                 ret = btrfs_end_transaction(trans, root);
6742                 BUG_ON(ret);
6743                 btrfs_btree_balance_dirty(root, nr);
6744
6745                 kfree(prev_root);
6746                 prev_root = reloc_root;
6747         }
6748         if (prev_root) {
6749                 btrfs_remove_leaf_refs(prev_root, (u64)-1, 0);
6750                 kfree(prev_root);
6751         }
6752         return 0;
6753 }
6754
6755 int btrfs_add_dead_reloc_root(struct btrfs_root *root)
6756 {
6757         list_add(&root->dead_list, &root->fs_info->dead_reloc_roots);
6758         return 0;
6759 }
6760
6761 int btrfs_cleanup_reloc_trees(struct btrfs_root *root)
6762 {
6763         struct btrfs_root *reloc_root;
6764         struct btrfs_trans_handle *trans;
6765         struct btrfs_key location;
6766         int found;
6767         int ret;
6768
6769         mutex_lock(&root->fs_info->tree_reloc_mutex);
6770         ret = btrfs_find_dead_roots(root, BTRFS_TREE_RELOC_OBJECTID, NULL);
6771         BUG_ON(ret);
6772         found = !list_empty(&root->fs_info->dead_reloc_roots);
6773         mutex_unlock(&root->fs_info->tree_reloc_mutex);
6774
6775         if (found) {
6776                 trans = btrfs_start_transaction(root, 1);
6777                 BUG_ON(!trans);
6778                 ret = btrfs_commit_transaction(trans, root);
6779                 BUG_ON(ret);
6780         }
6781
6782         location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
6783         location.offset = (u64)-1;
6784         location.type = BTRFS_ROOT_ITEM_KEY;
6785
6786         reloc_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
6787         BUG_ON(!reloc_root);
6788         btrfs_orphan_cleanup(reloc_root);
6789         return 0;
6790 }
6791
6792 static noinline int init_reloc_tree(struct btrfs_trans_handle *trans,
6793                                     struct btrfs_root *root)
6794 {
6795         struct btrfs_root *reloc_root;
6796         struct extent_buffer *eb;
6797         struct btrfs_root_item *root_item;
6798         struct btrfs_key root_key;
6799         int ret;
6800
6801         BUG_ON(!root->ref_cows);
6802         if (root->reloc_root)
6803                 return 0;
6804
6805         root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
6806         BUG_ON(!root_item);
6807
6808         ret = btrfs_copy_root(trans, root, root->commit_root,
6809                               &eb, BTRFS_TREE_RELOC_OBJECTID);
6810         BUG_ON(ret);
6811
6812         root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
6813         root_key.offset = root->root_key.objectid;
6814         root_key.type = BTRFS_ROOT_ITEM_KEY;
6815
6816         memcpy(root_item, &root->root_item, sizeof(root_item));
6817         btrfs_set_root_refs(root_item, 0);
6818         btrfs_set_root_bytenr(root_item, eb->start);
6819         btrfs_set_root_level(root_item, btrfs_header_level(eb));
6820         btrfs_set_root_generation(root_item, trans->transid);
6821
6822         btrfs_tree_unlock(eb);
6823         free_extent_buffer(eb);
6824
6825         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
6826                                 &root_key, root_item);
6827         BUG_ON(ret);
6828         kfree(root_item);
6829
6830         reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
6831                                                  &root_key);
6832         BUG_ON(!reloc_root);
6833         reloc_root->last_trans = trans->transid;
6834         reloc_root->commit_root = NULL;
6835         reloc_root->ref_tree = &root->fs_info->reloc_ref_tree;
6836
6837         root->reloc_root = reloc_root;
6838         return 0;
6839 }
6840
6841 /*
6842  * Core function of space balance.
6843  *
6844  * The idea is using reloc trees to relocate tree blocks in reference
6845  * counted roots. There is one reloc tree for each subvol, and all
6846  * reloc trees share same root key objectid. Reloc trees are snapshots
6847  * of the latest committed roots of subvols (root->commit_root).
6848  *
6849  * To relocate a tree block referenced by a subvol, there are two steps.
6850  * COW the block through subvol's reloc tree, then update block pointer
6851  * in the subvol to point to the new block. Since all reloc trees share
6852  * same root key objectid, doing special handing for tree blocks owned
6853  * by them is easy. Once a tree block has been COWed in one reloc tree,
6854  * we can use the resulting new block directly when the same block is
6855  * required to COW again through other reloc trees. By this way, relocated
6856  * tree blocks are shared between reloc trees, so they are also shared
6857  * between subvols.
6858  */
6859 static noinline int relocate_one_path(struct btrfs_trans_handle *trans,
6860                                       struct btrfs_root *root,
6861                                       struct btrfs_path *path,
6862                                       struct btrfs_key *first_key,
6863                                       struct btrfs_ref_path *ref_path,
6864                                       struct btrfs_block_group_cache *group,
6865                                       struct inode *reloc_inode)
6866 {
6867         struct btrfs_root *reloc_root;
6868         struct extent_buffer *eb = NULL;
6869         struct btrfs_key *keys;
6870         u64 *nodes;
6871         int level;
6872         int shared_level;
6873         int lowest_level = 0;
6874         int ret;
6875
6876         if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
6877                 lowest_level = ref_path->owner_objectid;
6878
6879         if (!root->ref_cows) {
6880                 path->lowest_level = lowest_level;
6881                 ret = btrfs_search_slot(trans, root, first_key, path, 0, 1);
6882                 BUG_ON(ret < 0);
6883                 path->lowest_level = 0;
6884                 btrfs_release_path(root, path);
6885                 return 0;
6886         }
6887
6888         mutex_lock(&root->fs_info->tree_reloc_mutex);
6889         ret = init_reloc_tree(trans, root);
6890         BUG_ON(ret);
6891         reloc_root = root->reloc_root;
6892
6893         shared_level = ref_path->shared_level;
6894         ref_path->shared_level = BTRFS_MAX_LEVEL - 1;
6895
6896         keys = ref_path->node_keys;
6897         nodes = ref_path->new_nodes;
6898         memset(&keys[shared_level + 1], 0,
6899                sizeof(*keys) * (BTRFS_MAX_LEVEL - shared_level - 1));
6900         memset(&nodes[shared_level + 1], 0,
6901                sizeof(*nodes) * (BTRFS_MAX_LEVEL - shared_level - 1));
6902
6903         if (nodes[lowest_level] == 0) {
6904                 path->lowest_level = lowest_level;
6905                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
6906                                         0, 1);
6907                 BUG_ON(ret);
6908                 for (level = lowest_level; level < BTRFS_MAX_LEVEL; level++) {
6909                         eb = path->nodes[level];
6910                         if (!eb || eb == reloc_root->node)
6911                                 break;
6912                         nodes[level] = eb->start;
6913                         if (level == 0)
6914                                 btrfs_item_key_to_cpu(eb, &keys[level], 0);
6915                         else
6916                                 btrfs_node_key_to_cpu(eb, &keys[level], 0);
6917                 }
6918                 if (nodes[0] &&
6919                     ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
6920                         eb = path->nodes[0];
6921                         ret = replace_extents_in_leaf(trans, reloc_root, eb,
6922                                                       group, reloc_inode);
6923                         BUG_ON(ret);
6924                 }
6925                 btrfs_release_path(reloc_root, path);
6926         } else {
6927                 ret = btrfs_merge_path(trans, reloc_root, keys, nodes,
6928                                        lowest_level);
6929                 BUG_ON(ret);
6930         }
6931
6932         /*
6933          * replace tree blocks in the fs tree with tree blocks in
6934          * the reloc tree.
6935          */
6936         ret = btrfs_merge_path(trans, root, keys, nodes, lowest_level);
6937         BUG_ON(ret < 0);
6938
6939         if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
6940                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
6941                                         0, 0);
6942                 BUG_ON(ret);
6943                 extent_buffer_get(path->nodes[0]);
6944                 eb = path->nodes[0];
6945                 btrfs_release_path(reloc_root, path);
6946                 ret = invalidate_extent_cache(reloc_root, eb, group, root);
6947                 BUG_ON(ret);
6948                 free_extent_buffer(eb);
6949         }
6950
6951         mutex_unlock(&root->fs_info->tree_reloc_mutex);
6952         path->lowest_level = 0;
6953         return 0;
6954 }
6955
6956 static noinline int relocate_tree_block(struct btrfs_trans_handle *trans,
6957                                         struct btrfs_root *root,
6958                                         struct btrfs_path *path,
6959                                         struct btrfs_key *first_key,
6960                                         struct btrfs_ref_path *ref_path)
6961 {
6962         int ret;
6963
6964         ret = relocate_one_path(trans, root, path, first_key,
6965                                 ref_path, NULL, NULL);
6966         BUG_ON(ret);
6967
6968         return 0;
6969 }
6970
6971 static noinline int del_extent_zero(struct btrfs_trans_handle *trans,
6972                                     struct btrfs_root *extent_root,
6973                                     struct btrfs_path *path,
6974                                     struct btrfs_key *extent_key)
6975 {
6976         int ret;
6977
6978         ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
6979         if (ret)
6980                 goto out;
6981         ret = btrfs_del_item(trans, extent_root, path);
6982 out:
6983         btrfs_release_path(extent_root, path);
6984         return ret;
6985 }
6986
6987 static noinline struct btrfs_root *read_ref_root(struct btrfs_fs_info *fs_info,
6988                                                 struct btrfs_ref_path *ref_path)
6989 {
6990         struct btrfs_key root_key;
6991
6992         root_key.objectid = ref_path->root_objectid;
6993         root_key.type = BTRFS_ROOT_ITEM_KEY;
6994         if (is_cowonly_root(ref_path->root_objectid))
6995                 root_key.offset = 0;
6996         else
6997                 root_key.offset = (u64)-1;
6998
6999         return btrfs_read_fs_root_no_name(fs_info, &root_key);
7000 }
7001
7002 static noinline int relocate_one_extent(struct btrfs_root *extent_root,
7003                                         struct btrfs_path *path,
7004                                         struct btrfs_key *extent_key,
7005                                         struct btrfs_block_group_cache *group,
7006                                         struct inode *reloc_inode, int pass)
7007 {
7008         struct btrfs_trans_handle *trans;
7009         struct btrfs_root *found_root;
7010         struct btrfs_ref_path *ref_path = NULL;
7011         struct disk_extent *new_extents = NULL;
7012         int nr_extents = 0;
7013         int loops;
7014         int ret;
7015         int level;
7016         struct btrfs_key first_key;
7017         u64 prev_block = 0;
7018
7019
7020         trans = btrfs_start_transaction(extent_root, 1);
7021         BUG_ON(!trans);
7022
7023         if (extent_key->objectid == 0) {
7024                 ret = del_extent_zero(trans, extent_root, path, extent_key);
7025                 goto out;
7026         }
7027
7028         ref_path = kmalloc(sizeof(*ref_path), GFP_NOFS);
7029         if (!ref_path) {
7030                 ret = -ENOMEM;
7031                 goto out;
7032         }
7033
7034         for (loops = 0; ; loops++) {
7035                 if (loops == 0) {
7036                         ret = btrfs_first_ref_path(trans, extent_root, ref_path,
7037                                                    extent_key->objectid);
7038                 } else {
7039                         ret = btrfs_next_ref_path(trans, extent_root, ref_path);
7040                 }
7041                 if (ret < 0)
7042                         goto out;
7043                 if (ret > 0)
7044                         break;
7045
7046                 if (ref_path->root_objectid == BTRFS_TREE_LOG_OBJECTID ||
7047                     ref_path->root_objectid == BTRFS_TREE_RELOC_OBJECTID)
7048                         continue;
7049
7050                 found_root = read_ref_root(extent_root->fs_info, ref_path);
7051                 BUG_ON(!found_root);
7052                 /*
7053                  * for reference counted tree, only process reference paths
7054                  * rooted at the latest committed root.
7055                  */
7056                 if (found_root->ref_cows &&
7057                     ref_path->root_generation != found_root->root_key.offset)
7058                         continue;
7059
7060                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
7061                         if (pass == 0) {
7062                                 /*
7063                                  * copy data extents to new locations
7064                                  */
7065                                 u64 group_start = group->key.objectid;
7066                                 ret = relocate_data_extent(reloc_inode,
7067                                                            extent_key,
7068                                                            group_start);
7069                                 if (ret < 0)
7070                                         goto out;
7071                                 break;
7072                         }
7073                         level = 0;
7074                 } else {
7075                         level = ref_path->owner_objectid;
7076                 }
7077
7078                 if (prev_block != ref_path->nodes[level]) {
7079                         struct extent_buffer *eb;
7080                         u64 block_start = ref_path->nodes[level];
7081                         u64 block_size = btrfs_level_size(found_root, level);
7082
7083                         eb = read_tree_block(found_root, block_start,
7084                                              block_size, 0);
7085                         btrfs_tree_lock(eb);
7086                         BUG_ON(level != btrfs_header_level(eb));
7087
7088                         if (level == 0)
7089                                 btrfs_item_key_to_cpu(eb, &first_key, 0);
7090                         else
7091                                 btrfs_node_key_to_cpu(eb, &first_key, 0);
7092
7093                         btrfs_tree_unlock(eb);
7094                         free_extent_buffer(eb);
7095                         prev_block = block_start;
7096                 }
7097
7098                 mutex_lock(&extent_root->fs_info->trans_mutex);
7099                 btrfs_record_root_in_trans(found_root);
7100                 mutex_unlock(&extent_root->fs_info->trans_mutex);
7101                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
7102                         /*
7103                          * try to update data extent references while
7104                          * keeping metadata shared between snapshots.
7105                          */
7106                         if (pass == 1) {
7107                                 ret = relocate_one_path(trans, found_root,
7108                                                 path, &first_key, ref_path,
7109                                                 group, reloc_inode);
7110                                 if (ret < 0)
7111                                         goto out;
7112                                 continue;
7113                         }
7114                         /*
7115                          * use fallback method to process the remaining
7116                          * references.
7117                          */
7118                         if (!new_extents) {
7119                                 u64 group_start = group->key.objectid;
7120                                 new_extents = kmalloc(sizeof(*new_extents),
7121                                                       GFP_NOFS);
7122                                 nr_extents = 1;
7123                                 ret = get_new_locations(reloc_inode,
7124                                                         extent_key,
7125                                                         group_start, 1,
7126                                                         &new_extents,
7127                                                         &nr_extents);
7128                                 if (ret)
7129                                         goto out;
7130                         }
7131                         ret = replace_one_extent(trans, found_root,
7132                                                 path, extent_key,
7133                                                 &first_key, ref_path,
7134                                                 new_extents, nr_extents);
7135                 } else {
7136                         ret = relocate_tree_block(trans, found_root, path,
7137                                                   &first_key, ref_path);
7138                 }
7139                 if (ret < 0)
7140                         goto out;
7141         }
7142         ret = 0;
7143 out:
7144         btrfs_end_transaction(trans, extent_root);
7145         kfree(new_extents);
7146         kfree(ref_path);
7147         return ret;
7148 }
7149 #endif
7150
7151 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7152 {
7153         u64 num_devices;
7154         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
7155                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7156
7157         num_devices = root->fs_info->fs_devices->rw_devices;
7158         if (num_devices == 1) {
7159                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7160                 stripped = flags & ~stripped;
7161
7162                 /* turn raid0 into single device chunks */
7163                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7164                         return stripped;
7165
7166                 /* turn mirroring into duplication */
7167                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7168                              BTRFS_BLOCK_GROUP_RAID10))
7169                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7170                 return flags;
7171         } else {
7172                 /* they already had raid on here, just return */
7173                 if (flags & stripped)
7174                         return flags;
7175
7176                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7177                 stripped = flags & ~stripped;
7178
7179                 /* switch duplicated blocks with raid1 */
7180                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7181                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7182
7183                 /* turn single device chunks into raid0 */
7184                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
7185         }
7186         return flags;
7187 }
7188
7189 static int __alloc_chunk_for_shrink(struct btrfs_root *root,
7190                      struct btrfs_block_group_cache *shrink_block_group,
7191                      int force)
7192 {
7193         struct btrfs_trans_handle *trans;
7194         u64 new_alloc_flags;
7195         u64 calc;
7196
7197         spin_lock(&shrink_block_group->lock);
7198         if (btrfs_block_group_used(&shrink_block_group->item) +
7199             shrink_block_group->reserved > 0) {
7200                 spin_unlock(&shrink_block_group->lock);
7201
7202                 trans = btrfs_start_transaction(root, 1);
7203                 spin_lock(&shrink_block_group->lock);
7204
7205                 new_alloc_flags = update_block_group_flags(root,
7206                                                    shrink_block_group->flags);
7207                 if (new_alloc_flags != shrink_block_group->flags) {
7208                         calc =
7209                              btrfs_block_group_used(&shrink_block_group->item);
7210                 } else {
7211                         calc = shrink_block_group->key.offset;
7212                 }
7213                 spin_unlock(&shrink_block_group->lock);
7214
7215                 do_chunk_alloc(trans, root->fs_info->extent_root,
7216                                calc + 2 * 1024 * 1024, new_alloc_flags, force);
7217
7218                 btrfs_end_transaction(trans, root);
7219         } else
7220                 spin_unlock(&shrink_block_group->lock);
7221         return 0;
7222 }
7223
7224
7225 int btrfs_prepare_block_group_relocation(struct btrfs_root *root,
7226                                          struct btrfs_block_group_cache *group)
7227
7228 {
7229         __alloc_chunk_for_shrink(root, group, 1);
7230         set_block_group_readonly(group);
7231         return 0;
7232 }
7233
7234 /*
7235  * checks to see if its even possible to relocate this block group.
7236  *
7237  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7238  * ok to go ahead and try.
7239  */
7240 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7241 {
7242         struct btrfs_block_group_cache *block_group;
7243         struct btrfs_space_info *space_info;
7244         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7245         struct btrfs_device *device;
7246         int full = 0;
7247         int ret = 0;
7248
7249         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7250
7251         /* odd, couldn't find the block group, leave it alone */
7252         if (!block_group)
7253                 return -1;
7254
7255         /* no bytes used, we're good */
7256         if (!btrfs_block_group_used(&block_group->item))
7257                 goto out;
7258
7259         space_info = block_group->space_info;
7260         spin_lock(&space_info->lock);
7261
7262         full = space_info->full;
7263
7264         /*
7265          * if this is the last block group we have in this space, we can't
7266          * relocate it unless we're able to allocate a new chunk below.
7267          *
7268          * Otherwise, we need to make sure we have room in the space to handle
7269          * all of the extents from this block group.  If we can, we're good
7270          */
7271         if ((space_info->total_bytes != block_group->key.offset) &&
7272            (space_info->bytes_used + space_info->bytes_reserved +
7273             space_info->bytes_pinned + space_info->bytes_readonly +
7274             btrfs_block_group_used(&block_group->item) <
7275             space_info->total_bytes)) {
7276                 spin_unlock(&space_info->lock);
7277                 goto out;
7278         }
7279         spin_unlock(&space_info->lock);
7280
7281         /*
7282          * ok we don't have enough space, but maybe we have free space on our
7283          * devices to allocate new chunks for relocation, so loop through our
7284          * alloc devices and guess if we have enough space.  However, if we
7285          * were marked as full, then we know there aren't enough chunks, and we
7286          * can just return.
7287          */
7288         ret = -1;
7289         if (full)
7290                 goto out;
7291
7292         mutex_lock(&root->fs_info->chunk_mutex);
7293         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7294                 u64 min_free = btrfs_block_group_used(&block_group->item);
7295                 u64 dev_offset, max_avail;
7296
7297                 /*
7298                  * check to make sure we can actually find a chunk with enough
7299                  * space to fit our block group in.
7300                  */
7301                 if (device->total_bytes > device->bytes_used + min_free) {
7302                         ret = find_free_dev_extent(NULL, device, min_free,
7303                                                    &dev_offset, &max_avail);
7304                         if (!ret)
7305                                 break;
7306                         ret = -1;
7307                 }
7308         }
7309         mutex_unlock(&root->fs_info->chunk_mutex);
7310 out:
7311         btrfs_put_block_group(block_group);
7312         return ret;
7313 }
7314
7315 static int find_first_block_group(struct btrfs_root *root,
7316                 struct btrfs_path *path, struct btrfs_key *key)
7317 {
7318         int ret = 0;
7319         struct btrfs_key found_key;
7320         struct extent_buffer *leaf;
7321         int slot;
7322
7323         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7324         if (ret < 0)
7325                 goto out;
7326
7327         while (1) {
7328                 slot = path->slots[0];
7329                 leaf = path->nodes[0];
7330                 if (slot >= btrfs_header_nritems(leaf)) {
7331                         ret = btrfs_next_leaf(root, path);
7332                         if (ret == 0)
7333                                 continue;
7334                         if (ret < 0)
7335                                 goto out;
7336                         break;
7337                 }
7338                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7339
7340                 if (found_key.objectid >= key->objectid &&
7341                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7342                         ret = 0;
7343                         goto out;
7344                 }
7345                 path->slots[0]++;
7346         }
7347         ret = -ENOENT;
7348 out:
7349         return ret;
7350 }
7351
7352 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7353 {
7354         struct btrfs_block_group_cache *block_group;
7355         struct btrfs_space_info *space_info;
7356         struct btrfs_caching_control *caching_ctl;
7357         struct rb_node *n;
7358
7359         down_write(&info->extent_commit_sem);
7360         while (!list_empty(&info->caching_block_groups)) {
7361                 caching_ctl = list_entry(info->caching_block_groups.next,
7362                                          struct btrfs_caching_control, list);
7363                 list_del(&caching_ctl->list);
7364                 put_caching_control(caching_ctl);
7365         }
7366         up_write(&info->extent_commit_sem);
7367
7368         spin_lock(&info->block_group_cache_lock);
7369         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7370                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7371                                        cache_node);
7372                 rb_erase(&block_group->cache_node,
7373                          &info->block_group_cache_tree);
7374                 spin_unlock(&info->block_group_cache_lock);
7375
7376                 down_write(&block_group->space_info->groups_sem);
7377                 list_del(&block_group->list);
7378                 up_write(&block_group->space_info->groups_sem);
7379
7380                 if (block_group->cached == BTRFS_CACHE_STARTED)
7381                         wait_block_group_cache_done(block_group);
7382
7383                 btrfs_remove_free_space_cache(block_group);
7384
7385                 WARN_ON(atomic_read(&block_group->count) != 1);
7386                 kfree(block_group);
7387
7388                 spin_lock(&info->block_group_cache_lock);
7389         }
7390         spin_unlock(&info->block_group_cache_lock);
7391
7392         /* now that all the block groups are freed, go through and
7393          * free all the space_info structs.  This is only called during
7394          * the final stages of unmount, and so we know nobody is
7395          * using them.  We call synchronize_rcu() once before we start,
7396          * just to be on the safe side.
7397          */
7398         synchronize_rcu();
7399
7400         while(!list_empty(&info->space_info)) {
7401                 space_info = list_entry(info->space_info.next,
7402                                         struct btrfs_space_info,
7403                                         list);
7404
7405                 list_del(&space_info->list);
7406                 kfree(space_info);
7407         }
7408         return 0;
7409 }
7410
7411 int btrfs_read_block_groups(struct btrfs_root *root)
7412 {
7413         struct btrfs_path *path;
7414         int ret;
7415         struct btrfs_block_group_cache *cache;
7416         struct btrfs_fs_info *info = root->fs_info;
7417         struct btrfs_space_info *space_info;
7418         struct btrfs_key key;
7419         struct btrfs_key found_key;
7420         struct extent_buffer *leaf;
7421
7422         root = info->extent_root;
7423         key.objectid = 0;
7424         key.offset = 0;
7425         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
7426         path = btrfs_alloc_path();
7427         if (!path)
7428                 return -ENOMEM;
7429
7430         while (1) {
7431                 ret = find_first_block_group(root, path, &key);
7432                 if (ret > 0) {
7433                         ret = 0;
7434                         goto error;
7435                 }
7436                 if (ret != 0)
7437                         goto error;
7438
7439                 leaf = path->nodes[0];
7440                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
7441                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
7442                 if (!cache) {
7443                         ret = -ENOMEM;
7444                         break;
7445                 }
7446
7447                 atomic_set(&cache->count, 1);
7448                 spin_lock_init(&cache->lock);
7449                 spin_lock_init(&cache->tree_lock);
7450                 cache->fs_info = info;
7451                 INIT_LIST_HEAD(&cache->list);
7452                 INIT_LIST_HEAD(&cache->cluster_list);
7453
7454                 /*
7455                  * we only want to have 32k of ram per block group for keeping
7456                  * track of free space, and if we pass 1/2 of that we want to
7457                  * start converting things over to using bitmaps
7458                  */
7459                 cache->extents_thresh = ((1024 * 32) / 2) /
7460                         sizeof(struct btrfs_free_space);
7461
7462                 read_extent_buffer(leaf, &cache->item,
7463                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7464                                    sizeof(cache->item));
7465                 memcpy(&cache->key, &found_key, sizeof(found_key));
7466
7467                 key.objectid = found_key.objectid + found_key.offset;
7468                 btrfs_release_path(root, path);
7469                 cache->flags = btrfs_block_group_flags(&cache->item);
7470                 cache->sectorsize = root->sectorsize;
7471
7472                 /*
7473                  * check for two cases, either we are full, and therefore
7474                  * don't need to bother with the caching work since we won't
7475                  * find any space, or we are empty, and we can just add all
7476                  * the space in and be done with it.  This saves us _alot_ of
7477                  * time, particularly in the full case.
7478                  */
7479                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7480                         exclude_super_stripes(root, cache);
7481                         cache->last_byte_to_unpin = (u64)-1;
7482                         cache->cached = BTRFS_CACHE_FINISHED;
7483                         free_excluded_extents(root, cache);
7484                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7485                         exclude_super_stripes(root, cache);
7486                         cache->last_byte_to_unpin = (u64)-1;
7487                         cache->cached = BTRFS_CACHE_FINISHED;
7488                         add_new_free_space(cache, root->fs_info,
7489                                            found_key.objectid,
7490                                            found_key.objectid +
7491                                            found_key.offset);
7492                         free_excluded_extents(root, cache);
7493                 }
7494
7495                 ret = update_space_info(info, cache->flags, found_key.offset,
7496                                         btrfs_block_group_used(&cache->item),
7497                                         &space_info);
7498                 BUG_ON(ret);
7499                 cache->space_info = space_info;
7500                 spin_lock(&cache->space_info->lock);
7501                 cache->space_info->bytes_super += cache->bytes_super;
7502                 spin_unlock(&cache->space_info->lock);
7503
7504                 down_write(&space_info->groups_sem);
7505                 list_add_tail(&cache->list, &space_info->block_groups);
7506                 up_write(&space_info->groups_sem);
7507
7508                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7509                 BUG_ON(ret);
7510
7511                 set_avail_alloc_bits(root->fs_info, cache->flags);
7512                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7513                         set_block_group_readonly(cache);
7514         }
7515         ret = 0;
7516 error:
7517         btrfs_free_path(path);
7518         return ret;
7519 }
7520
7521 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7522                            struct btrfs_root *root, u64 bytes_used,
7523                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7524                            u64 size)
7525 {
7526         int ret;
7527         struct btrfs_root *extent_root;
7528         struct btrfs_block_group_cache *cache;
7529
7530         extent_root = root->fs_info->extent_root;
7531
7532         root->fs_info->last_trans_log_full_commit = trans->transid;
7533
7534         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7535         if (!cache)
7536                 return -ENOMEM;
7537
7538         cache->key.objectid = chunk_offset;
7539         cache->key.offset = size;
7540         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7541         cache->sectorsize = root->sectorsize;
7542
7543         /*
7544          * we only want to have 32k of ram per block group for keeping track
7545          * of free space, and if we pass 1/2 of that we want to start
7546          * converting things over to using bitmaps
7547          */
7548         cache->extents_thresh = ((1024 * 32) / 2) /
7549                 sizeof(struct btrfs_free_space);
7550         atomic_set(&cache->count, 1);
7551         spin_lock_init(&cache->lock);
7552         spin_lock_init(&cache->tree_lock);
7553         INIT_LIST_HEAD(&cache->list);
7554         INIT_LIST_HEAD(&cache->cluster_list);
7555
7556         btrfs_set_block_group_used(&cache->item, bytes_used);
7557         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7558         cache->flags = type;
7559         btrfs_set_block_group_flags(&cache->item, type);
7560
7561         cache->last_byte_to_unpin = (u64)-1;
7562         cache->cached = BTRFS_CACHE_FINISHED;
7563         exclude_super_stripes(root, cache);
7564
7565         add_new_free_space(cache, root->fs_info, chunk_offset,
7566                            chunk_offset + size);
7567
7568         free_excluded_extents(root, cache);
7569
7570         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7571                                 &cache->space_info);
7572         BUG_ON(ret);
7573
7574         spin_lock(&cache->space_info->lock);
7575         cache->space_info->bytes_super += cache->bytes_super;
7576         spin_unlock(&cache->space_info->lock);
7577
7578         down_write(&cache->space_info->groups_sem);
7579         list_add_tail(&cache->list, &cache->space_info->block_groups);
7580         up_write(&cache->space_info->groups_sem);
7581
7582         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7583         BUG_ON(ret);
7584
7585         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7586                                 sizeof(cache->item));
7587         BUG_ON(ret);
7588
7589         set_avail_alloc_bits(extent_root->fs_info, type);
7590
7591         return 0;
7592 }
7593
7594 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7595                              struct btrfs_root *root, u64 group_start)
7596 {
7597         struct btrfs_path *path;
7598         struct btrfs_block_group_cache *block_group;
7599         struct btrfs_free_cluster *cluster;
7600         struct btrfs_key key;
7601         int ret;
7602
7603         root = root->fs_info->extent_root;
7604
7605         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7606         BUG_ON(!block_group);
7607         BUG_ON(!block_group->ro);
7608
7609         memcpy(&key, &block_group->key, sizeof(key));
7610
7611         /* make sure this block group isn't part of an allocation cluster */
7612         cluster = &root->fs_info->data_alloc_cluster;
7613         spin_lock(&cluster->refill_lock);
7614         btrfs_return_cluster_to_free_space(block_group, cluster);
7615         spin_unlock(&cluster->refill_lock);
7616
7617         /*
7618          * make sure this block group isn't part of a metadata
7619          * allocation cluster
7620          */
7621         cluster = &root->fs_info->meta_alloc_cluster;
7622         spin_lock(&cluster->refill_lock);
7623         btrfs_return_cluster_to_free_space(block_group, cluster);
7624         spin_unlock(&cluster->refill_lock);
7625
7626         path = btrfs_alloc_path();
7627         BUG_ON(!path);
7628
7629         spin_lock(&root->fs_info->block_group_cache_lock);
7630         rb_erase(&block_group->cache_node,
7631                  &root->fs_info->block_group_cache_tree);
7632         spin_unlock(&root->fs_info->block_group_cache_lock);
7633
7634         down_write(&block_group->space_info->groups_sem);
7635         /*
7636          * we must use list_del_init so people can check to see if they
7637          * are still on the list after taking the semaphore
7638          */
7639         list_del_init(&block_group->list);
7640         up_write(&block_group->space_info->groups_sem);
7641
7642         if (block_group->cached == BTRFS_CACHE_STARTED)
7643                 wait_block_group_cache_done(block_group);
7644
7645         btrfs_remove_free_space_cache(block_group);
7646
7647         spin_lock(&block_group->space_info->lock);
7648         block_group->space_info->total_bytes -= block_group->key.offset;
7649         block_group->space_info->bytes_readonly -= block_group->key.offset;
7650         spin_unlock(&block_group->space_info->lock);
7651
7652         btrfs_clear_space_info_full(root->fs_info);
7653
7654         btrfs_put_block_group(block_group);
7655         btrfs_put_block_group(block_group);
7656
7657         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
7658         if (ret > 0)
7659                 ret = -EIO;
7660         if (ret < 0)
7661                 goto out;
7662
7663         ret = btrfs_del_item(trans, root, path);
7664 out:
7665         btrfs_free_path(path);
7666         return ret;
7667 }