fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include "compat.h"
  27 #include "hash.h"
  28 #include "ctree.h"
  29 #include "disk-io.h"
  30 #include "print-tree.h"
  31 #include "transaction.h"
  32 #include "volumes.h"
  33 #include "locking.h"
  34 #include "free-space-cache.h"
  35
  36 static int update_block_group(struct btrfs_trans_handle *trans,
  37                               struct btrfs_root *root,
  38                               u64 bytenr, u64 num_bytes, int alloc);
  39 static int update_reserved_bytes(struct btrfs_block_group_cache *cache,
  40                                  u64 num_bytes, int reserve, int sinfo);
  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 find_next_key(struct btrfs_path *path, int level,
  64                          struct btrfs_key *key);
  65 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
  66                             int dump_block_groups);
  67
  68 static noinline int
  69 block_group_cache_done(struct btrfs_block_group_cache *cache)
  70 {
  71         smp_mb();
  72         return cache->cached == BTRFS_CACHE_FINISHED;
  73 }
  74
  75 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  76 {
  77         return (cache->flags & bits) == bits;
  78 }
  79
  80 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
  81 {
  82         atomic_inc(&cache->count);
  83 }
  84
  85 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
  86 {
  87         if (atomic_dec_and_test(&cache->count)) {
  88                 WARN_ON(cache->pinned > 0);
  89                 WARN_ON(cache->reserved > 0);
  90                 WARN_ON(cache->reserved_pinned > 0);
  91                 kfree(cache);
  92         }
  93 }
  94
  95 /*
  96  * this adds the block group to the fs_info rb tree for the block group
  97  * cache
  98  */
  99 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 100                                 struct btrfs_block_group_cache *block_group)
 101 {
 102         struct rb_node **p;
 103         struct rb_node *parent = NULL;
 104         struct btrfs_block_group_cache *cache;
 105
 106         spin_lock(&info->block_group_cache_lock);
 107         p = &info->block_group_cache_tree.rb_node;
 108
 109         while (*p) {
 110                 parent = *p;
 111                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 112                                  cache_node);
 113                 if (block_group->key.objectid < cache->key.objectid) {
 114                         p = &(*p)->rb_left;
 115                 } else if (block_group->key.objectid > cache->key.objectid) {
 116                         p = &(*p)->rb_right;
 117                 } else {
 118                         spin_unlock(&info->block_group_cache_lock);
 119                         return -EEXIST;
 120                 }
 121         }
 122
 123         rb_link_node(&block_group->cache_node, parent, p);
 124         rb_insert_color(&block_group->cache_node,
 125                         &info->block_group_cache_tree);
 126         spin_unlock(&info->block_group_cache_lock);
 127
 128         return 0;
 129 }
 130
 131 /*
 132  * This will return the block group at or after bytenr if contains is 0, else
 133  * it will return the block group that contains the bytenr
 134  */
 135 static struct btrfs_block_group_cache *
 136 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 137                               int contains)
 138 {
 139         struct btrfs_block_group_cache *cache, *ret = NULL;
 140         struct rb_node *n;
 141         u64 end, start;
 142
 143         spin_lock(&info->block_group_cache_lock);
 144         n = info->block_group_cache_tree.rb_node;
 145
 146         while (n) {
 147                 cache = rb_entry(n, struct btrfs_block_group_cache,
 148                                  cache_node);
 149                 end = cache->key.objectid + cache->key.offset - 1;
 150                 start = cache->key.objectid;
 151
 152                 if (bytenr < start) {
 153                         if (!contains && (!ret || start < ret->key.objectid))
 154                                 ret = cache;
 155                         n = n->rb_left;
 156                 } else if (bytenr > start) {
 157                         if (contains && bytenr <= end) {
 158                                 ret = cache;
 159                                 break;
 160                         }
 161                         n = n->rb_right;
 162                 } else {
 163                         ret = cache;
 164                         break;
 165                 }
 166         }
 167         if (ret)
 168                 btrfs_get_block_group(ret);
 169         spin_unlock(&info->block_group_cache_lock);
 170
 171         return ret;
 172 }
 173
 174 static int add_excluded_extent(struct btrfs_root *root,
 175                                u64 start, u64 num_bytes)
 176 {
 177         u64 end = start + num_bytes - 1;
 178         set_extent_bits(&root->fs_info->freed_extents[0],
 179                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 180         set_extent_bits(&root->fs_info->freed_extents[1],
 181                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 182         return 0;
 183 }
 184
 185 static void free_excluded_extents(struct btrfs_root *root,
 186                                   struct btrfs_block_group_cache *cache)
 187 {
 188         u64 start, end;
 189
 190         start = cache->key.objectid;
 191         end = start + cache->key.offset - 1;
 192
 193         clear_extent_bits(&root->fs_info->freed_extents[0],
 194                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 195         clear_extent_bits(&root->fs_info->freed_extents[1],
 196                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 197 }
 198
 199 static int exclude_super_stripes(struct btrfs_root *root,
 200                                  struct btrfs_block_group_cache *cache)
 201 {
 202         u64 bytenr;
 203         u64 *logical;
 204         int stripe_len;
 205         int i, nr, ret;
 206
 207         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 208                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 209                 cache->bytes_super += stripe_len;
 210                 ret = add_excluded_extent(root, cache->key.objectid,
 211                                           stripe_len);
 212                 BUG_ON(ret);
 213         }
 214
 215         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 216                 bytenr = btrfs_sb_offset(i);
 217                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 218                                        cache->key.objectid, bytenr,
 219                                        0, &logical, &nr, &stripe_len);
 220                 BUG_ON(ret);
 221
 222                 while (nr--) {
 223                         cache->bytes_super += stripe_len;
 224                         ret = add_excluded_extent(root, logical[nr],
 225                                                   stripe_len);
 226                         BUG_ON(ret);
 227                 }
 228
 229                 kfree(logical);
 230         }
 231         return 0;
 232 }
 233
 234 static struct btrfs_caching_control *
 235 get_caching_control(struct btrfs_block_group_cache *cache)
 236 {
 237         struct btrfs_caching_control *ctl;
 238
 239         spin_lock(&cache->lock);
 240         if (cache->cached != BTRFS_CACHE_STARTED) {
 241                 spin_unlock(&cache->lock);
 242                 return NULL;
 243         }
 244
 245         ctl = cache->caching_ctl;
 246         atomic_inc(&ctl->count);
 247         spin_unlock(&cache->lock);
 248         return ctl;
 249 }
 250
 251 static void put_caching_control(struct btrfs_caching_control *ctl)
 252 {
 253         if (atomic_dec_and_test(&ctl->count))
 254                 kfree(ctl);
 255 }
 256
 257 /*
 258  * this is only called by cache_block_group, since we could have freed extents
 259  * we need to check the pinned_extents for any extents that can't be used yet
 260  * since their free space will be released as soon as the transaction commits.
 261  */
 262 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 263                               struct btrfs_fs_info *info, u64 start, u64 end)
 264 {
 265         u64 extent_start, extent_end, size, total_added = 0;
 266         int ret;
 267
 268         while (start < end) {
 269                 ret = find_first_extent_bit(info->pinned_extents, start,
 270                                             &extent_start, &extent_end,
 271                                             EXTENT_DIRTY | EXTENT_UPTODATE);
 272                 if (ret)
 273                         break;
 274
 275                 if (extent_start <= start) {
 276                         start = extent_end + 1;
 277                 } else if (extent_start > start && extent_start < end) {
 278                         size = extent_start - start;
 279                         total_added += size;
 280                         ret = btrfs_add_free_space(block_group, start,
 281                                                    size);
 282                         BUG_ON(ret);
 283                         start = extent_end + 1;
 284                 } else {
 285                         break;
 286                 }
 287         }
 288
 289         if (start < end) {
 290                 size = end - start;
 291                 total_added += size;
 292                 ret = btrfs_add_free_space(block_group, start, size);
 293                 BUG_ON(ret);
 294         }
 295
 296         return total_added;
 297 }
 298
 299 static int caching_kthread(void *data)
 300 {
 301         struct btrfs_block_group_cache *block_group = data;
 302         struct btrfs_fs_info *fs_info = block_group->fs_info;
 303         struct btrfs_caching_control *caching_ctl = block_group->caching_ctl;
 304         struct btrfs_root *extent_root = fs_info->extent_root;
 305         struct btrfs_path *path;
 306         struct extent_buffer *leaf;
 307         struct btrfs_key key;
 308         u64 total_found = 0;
 309         u64 last = 0;
 310         u32 nritems;
 311         int ret = 0;
 312
 313         path = btrfs_alloc_path();
 314         if (!path)
 315                 return -ENOMEM;
 316
 317         exclude_super_stripes(extent_root, block_group);
 318         spin_lock(&block_group->space_info->lock);
 319         block_group->space_info->bytes_readonly += block_group->bytes_super;
 320         spin_unlock(&block_group->space_info->lock);
 321
 322         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 323
 324         /*
 325          * We don't want to deadlock with somebody trying to allocate a new
 326          * extent for the extent root while also trying to search the extent
 327          * root to add free space.  So we skip locking and search the commit
 328          * root, since its read-only
 329          */
 330         path->skip_locking = 1;
 331         path->search_commit_root = 1;
 332         path->reada = 2;
 333
 334         key.objectid = last;
 335         key.offset = 0;
 336         key.type = BTRFS_EXTENT_ITEM_KEY;
 337 again:
 338         mutex_lock(&caching_ctl->mutex);
 339         /* need to make sure the commit_root doesn't disappear */
 340         down_read(&fs_info->extent_commit_sem);
 341
 342         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 343         if (ret < 0)
 344                 goto err;
 345
 346         leaf = path->nodes[0];
 347         nritems = btrfs_header_nritems(leaf);
 348
 349         while (1) {
 350                 smp_mb();
 351                 if (fs_info->closing > 1) {
 352                         last = (u64)-1;
 353                         break;
 354                 }
 355
 356                 if (path->slots[0] < nritems) {
 357                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 358                 } else {
 359                         ret = find_next_key(path, 0, &key);
 360                         if (ret)
 361                                 break;
 362
 363                         caching_ctl->progress = last;
 364                         btrfs_release_path(extent_root, path);
 365                         up_read(&fs_info->extent_commit_sem);
 366                         mutex_unlock(&caching_ctl->mutex);
 367                         if (btrfs_transaction_in_commit(fs_info))
 368                                 schedule_timeout(1);
 369                         else
 370                                 cond_resched();
 371                         goto again;
 372                 }
 373
 374                 if (key.objectid < block_group->key.objectid) {
 375                         path->slots[0]++;
 376                         continue;
 377                 }
 378
 379                 if (key.objectid >= block_group->key.objectid +
 380                     block_group->key.offset)
 381                         break;
 382
 383                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 384                         total_found += add_new_free_space(block_group,
 385                                                           fs_info, last,
 386                                                           key.objectid);
 387                         last = key.objectid + key.offset;
 388
 389                         if (total_found > (1024 * 1024 * 2)) {
 390                                 total_found = 0;
 391                                 wake_up(&caching_ctl->wait);
 392                         }
 393                 }
 394                 path->slots[0]++;
 395         }
 396         ret = 0;
 397
 398         total_found += add_new_free_space(block_group, fs_info, last,
 399                                           block_group->key.objectid +
 400                                           block_group->key.offset);
 401         caching_ctl->progress = (u64)-1;
 402
 403         spin_lock(&block_group->lock);
 404         block_group->caching_ctl = NULL;
 405         block_group->cached = BTRFS_CACHE_FINISHED;
 406         spin_unlock(&block_group->lock);
 407
 408 err:
 409         btrfs_free_path(path);
 410         up_read(&fs_info->extent_commit_sem);
 411
 412         free_excluded_extents(extent_root, block_group);
 413
 414         mutex_unlock(&caching_ctl->mutex);
 415         wake_up(&caching_ctl->wait);
 416
 417         put_caching_control(caching_ctl);
 418         atomic_dec(&block_group->space_info->caching_threads);
 419         btrfs_put_block_group(block_group);
 420
 421         return 0;
 422 }
 423
 424 static int cache_block_group(struct btrfs_block_group_cache *cache)
 425 {
 426         struct btrfs_fs_info *fs_info = cache->fs_info;
 427         struct btrfs_caching_control *caching_ctl;
 428         struct task_struct *tsk;
 429         int ret = 0;
 430
 431         smp_mb();
 432         if (cache->cached != BTRFS_CACHE_NO)
 433                 return 0;
 434
 435         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_KERNEL);
 436         BUG_ON(!caching_ctl);
 437
 438         INIT_LIST_HEAD(&caching_ctl->list);
 439         mutex_init(&caching_ctl->mutex);
 440         init_waitqueue_head(&caching_ctl->wait);
 441         caching_ctl->block_group = cache;
 442         caching_ctl->progress = cache->key.objectid;
 443         /* one for caching kthread, one for caching block group list */
 444         atomic_set(&caching_ctl->count, 2);
 445
 446         spin_lock(&cache->lock);
 447         if (cache->cached != BTRFS_CACHE_NO) {
 448                 spin_unlock(&cache->lock);
 449                 kfree(caching_ctl);
 450                 return 0;
 451         }
 452         cache->caching_ctl = caching_ctl;
 453         cache->cached = BTRFS_CACHE_STARTED;
 454         spin_unlock(&cache->lock);
 455
 456         down_write(&fs_info->extent_commit_sem);
 457         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 458         up_write(&fs_info->extent_commit_sem);
 459
 460         atomic_inc(&cache->space_info->caching_threads);
 461         btrfs_get_block_group(cache);
 462
 463         tsk = kthread_run(caching_kthread, cache, "btrfs-cache-%llu\n",
 464                           cache->key.objectid);
 465         if (IS_ERR(tsk)) {
 466                 ret = PTR_ERR(tsk);
 467                 printk(KERN_ERR "error running thread %d\n", ret);
 468                 BUG();
 469         }
 470
 471         return ret;
 472 }
 473
 474 /*
 475  * return the block group that starts at or after bytenr
 476  */
 477 static struct btrfs_block_group_cache *
 478 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 479 {
 480         struct btrfs_block_group_cache *cache;
 481
 482         cache = block_group_cache_tree_search(info, bytenr, 0);
 483
 484         return cache;
 485 }
 486
 487 /*
 488  * return the block group that contains the given bytenr
 489  */
 490 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 491                                                  struct btrfs_fs_info *info,
 492                                                  u64 bytenr)
 493 {
 494         struct btrfs_block_group_cache *cache;
 495
 496         cache = block_group_cache_tree_search(info, bytenr, 1);
 497
 498         return cache;
 499 }
 500
 501 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 502                                                   u64 flags)
 503 {
 504         struct list_head *head = &info->space_info;
 505         struct btrfs_space_info *found;
 506
 507         flags &= BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_SYSTEM |
 508                  BTRFS_BLOCK_GROUP_METADATA;
 509
 510         rcu_read_lock();
 511         list_for_each_entry_rcu(found, head, list) {
 512                 if (found->flags == flags) {
 513                         rcu_read_unlock();
 514                         return found;
 515                 }
 516         }
 517         rcu_read_unlock();
 518         return NULL;
 519 }
 520
 521 /*
 522  * after adding space to the filesystem, we need to clear the full flags
 523  * on all the space infos.
 524  */
 525 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 526 {
 527         struct list_head *head = &info->space_info;
 528         struct btrfs_space_info *found;
 529
 530         rcu_read_lock();
 531         list_for_each_entry_rcu(found, head, list)
 532                 found->full = 0;
 533         rcu_read_unlock();
 534 }
 535
 536 static u64 div_factor(u64 num, int factor)
 537 {
 538         if (factor == 10)
 539                 return num;
 540         num *= factor;
 541         do_div(num, 10);
 542         return num;
 543 }
 544
 545 u64 btrfs_find_block_group(struct btrfs_root *root,
 546                            u64 search_start, u64 search_hint, int owner)
 547 {
 548         struct btrfs_block_group_cache *cache;
 549         u64 used;
 550         u64 last = max(search_hint, search_start);
 551         u64 group_start = 0;
 552         int full_search = 0;
 553         int factor = 9;
 554         int wrapped = 0;
 555 again:
 556         while (1) {
 557                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 558                 if (!cache)
 559                         break;
 560
 561                 spin_lock(&cache->lock);
 562                 last = cache->key.objectid + cache->key.offset;
 563                 used = btrfs_block_group_used(&cache->item);
 564
 565                 if ((full_search || !cache->ro) &&
 566                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 567                         if (used + cache->pinned + cache->reserved <
 568                             div_factor(cache->key.offset, factor)) {
 569                                 group_start = cache->key.objectid;
 570                                 spin_unlock(&cache->lock);
 571                                 btrfs_put_block_group(cache);
 572                                 goto found;
 573                         }
 574                 }
 575                 spin_unlock(&cache->lock);
 576                 btrfs_put_block_group(cache);
 577                 cond_resched();
 578         }
 579         if (!wrapped) {
 580                 last = search_start;
 581                 wrapped = 1;
 582                 goto again;
 583         }
 584         if (!full_search && factor < 10) {
 585                 last = search_start;
 586                 full_search = 1;
 587                 factor = 10;
 588                 goto again;
 589         }
 590 found:
 591         return group_start;
 592 }
 593
 594 /* simple helper to search for an existing extent at a given offset */
 595 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 596 {
 597         int ret;
 598         struct btrfs_key key;
 599         struct btrfs_path *path;
 600
 601         path = btrfs_alloc_path();
 602         BUG_ON(!path);
 603         key.objectid = start;
 604         key.offset = len;
 605         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 606         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 607                                 0, 0);
 608         btrfs_free_path(path);
 609         return ret;
 610 }
 611
 612 /*
 613  * helper function to lookup reference count and flags of extent.
 614  *
 615  * the head node for delayed ref is used to store the sum of all the
 616  * reference count modifications queued up in the rbtree. the head
 617  * node may also store the extent flags to set. This way you can check
 618  * to see what the reference count and extent flags would be if all of
 619  * the delayed refs are not processed.
 620  */
 621 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 622                              struct btrfs_root *root, u64 bytenr,
 623                              u64 num_bytes, u64 *refs, u64 *flags)
 624 {
 625         struct btrfs_delayed_ref_head *head;
 626         struct btrfs_delayed_ref_root *delayed_refs;
 627         struct btrfs_path *path;
 628         struct btrfs_extent_item *ei;
 629         struct extent_buffer *leaf;
 630         struct btrfs_key key;
 631         u32 item_size;
 632         u64 num_refs;
 633         u64 extent_flags;
 634         int ret;
 635
 636         path = btrfs_alloc_path();
 637         if (!path)
 638                 return -ENOMEM;
 639
 640         key.objectid = bytenr;
 641         key.type = BTRFS_EXTENT_ITEM_KEY;
 642         key.offset = num_bytes;
 643         if (!trans) {
 644                 path->skip_locking = 1;
 645                 path->search_commit_root = 1;
 646         }
 647 again:
 648         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 649                                 &key, path, 0, 0);
 650         if (ret < 0)
 651                 goto out_free;
 652
 653         if (ret == 0) {
 654                 leaf = path->nodes[0];
 655                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 656                 if (item_size >= sizeof(*ei)) {
 657                         ei = btrfs_item_ptr(leaf, path->slots[0],
 658                                             struct btrfs_extent_item);
 659                         num_refs = btrfs_extent_refs(leaf, ei);
 660                         extent_flags = btrfs_extent_flags(leaf, ei);
 661                 } else {
 662 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 663                         struct btrfs_extent_item_v0 *ei0;
 664                         BUG_ON(item_size != sizeof(*ei0));
 665                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 666                                              struct btrfs_extent_item_v0);
 667                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 668                         /* FIXME: this isn't correct for data */
 669                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 670 #else
 671                         BUG();
 672 #endif
 673                 }
 674                 BUG_ON(num_refs == 0);
 675         } else {
 676                 num_refs = 0;
 677                 extent_flags = 0;
 678                 ret = 0;
 679         }
 680
 681         if (!trans)
 682                 goto out;
 683
 684         delayed_refs = &trans->transaction->delayed_refs;
 685         spin_lock(&delayed_refs->lock);
 686         head = btrfs_find_delayed_ref_head(trans, bytenr);
 687         if (head) {
 688                 if (!mutex_trylock(&head->mutex)) {
 689                         atomic_inc(&head->node.refs);
 690                         spin_unlock(&delayed_refs->lock);
 691
 692                         btrfs_release_path(root->fs_info->extent_root, path);
 693
 694                         mutex_lock(&head->mutex);
 695                         mutex_unlock(&head->mutex);
 696                         btrfs_put_delayed_ref(&head->node);
 697                         goto again;
 698                 }
 699                 if (head->extent_op && head->extent_op->update_flags)
 700                         extent_flags |= head->extent_op->flags_to_set;
 701                 else
 702                         BUG_ON(num_refs == 0);
 703
 704                 num_refs += head->node.ref_mod;
 705                 mutex_unlock(&head->mutex);
 706         }
 707         spin_unlock(&delayed_refs->lock);
 708 out:
 709         WARN_ON(num_refs == 0);
 710         if (refs)
 711                 *refs = num_refs;
 712         if (flags)
 713                 *flags = extent_flags;
 714 out_free:
 715         btrfs_free_path(path);
 716         return ret;
 717 }
 718
 719 /*
 720  * Back reference rules.  Back refs have three main goals:
 721  *
 722  * 1) differentiate between all holders of references to an extent so that
 723  *    when a reference is dropped we can make sure it was a valid reference
 724  *    before freeing the extent.
 725  *
 726  * 2) Provide enough information to quickly find the holders of an extent
 727  *    if we notice a given block is corrupted or bad.
 728  *
 729  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 730  *    maintenance.  This is actually the same as #2, but with a slightly
 731  *    different use case.
 732  *
 733  * There are two kinds of back refs. The implicit back refs is optimized
 734  * for pointers in non-shared tree blocks. For a given pointer in a block,
 735  * back refs of this kind provide information about the block's owner tree
 736  * and the pointer's key. These information allow us to find the block by
 737  * b-tree searching. The full back refs is for pointers in tree blocks not
 738  * referenced by their owner trees. The location of tree block is recorded
 739  * in the back refs. Actually the full back refs is generic, and can be
 740  * used in all cases the implicit back refs is used. The major shortcoming
 741  * of the full back refs is its overhead. Every time a tree block gets
 742  * COWed, we have to update back refs entry for all pointers in it.
 743  *
 744  * For a newly allocated tree block, we use implicit back refs for
 745  * pointers in it. This means most tree related operations only involve
 746  * implicit back refs. For a tree block created in old transaction, the
 747  * only way to drop a reference to it is COW it. So we can detect the
 748  * event that tree block loses its owner tree's reference and do the
 749  * back refs conversion.
 750  *
 751  * When a tree block is COW'd through a tree, there are four cases:
 752  *
 753  * The reference count of the block is one and the tree is the block's
 754  * owner tree. Nothing to do in this case.
 755  *
 756  * The reference count of the block is one and the tree is not the
 757  * block's owner tree. In this case, full back refs is used for pointers
 758  * in the block. Remove these full back refs, add implicit back refs for
 759  * every pointers in the new block.
 760  *
 761  * The reference count of the block is greater than one and the tree is
 762  * the block's owner tree. In this case, implicit back refs is used for
 763  * pointers in the block. Add full back refs for every pointers in the
 764  * block, increase lower level extents' reference counts. The original
 765  * implicit back refs are entailed to the new block.
 766  *
 767  * The reference count of the block is greater than one and the tree is
 768  * not the block's owner tree. Add implicit back refs for every pointer in
 769  * the new block, increase lower level extents' reference count.
 770  *
 771  * Back Reference Key composing:
 772  *
 773  * The key objectid corresponds to the first byte in the extent,
 774  * The key type is used to differentiate between types of back refs.
 775  * There are different meanings of the key offset for different types
 776  * of back refs.
 777  *
 778  * File extents can be referenced by:
 779  *
 780  * - multiple snapshots, subvolumes, or different generations in one subvol
 781  * - different files inside a single subvolume
 782  * - different offsets inside a file (bookend extents in file.c)
 783  *
 784  * The extent ref structure for the implicit back refs has fields for:
 785  *
 786  * - Objectid of the subvolume root
 787  * - objectid of the file holding the reference
 788  * - original offset in the file
 789  * - how many bookend extents
 790  *
 791  * The key offset for the implicit back refs is hash of the first
 792  * three fields.
 793  *
 794  * The extent ref structure for the full back refs has field for:
 795  *
 796  * - number of pointers in the tree leaf
 797  *
 798  * The key offset for the implicit back refs is the first byte of
 799  * the tree leaf
 800  *
 801  * When a file extent is allocated, The implicit back refs is used.
 802  * the fields are filled in:
 803  *
 804  *     (root_key.objectid, inode objectid, offset in file, 1)
 805  *
 806  * When a file extent is removed file truncation, we find the
 807  * corresponding implicit back refs and check the following fields:
 808  *
 809  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 810  *
 811  * Btree extents can be referenced by:
 812  *
 813  * - Different subvolumes
 814  *
 815  * Both the implicit back refs and the full back refs for tree blocks
 816  * only consist of key. The key offset for the implicit back refs is
 817  * objectid of block's owner tree. The key offset for the full back refs
 818  * is the first byte of parent block.
 819  *
 820  * When implicit back refs is used, information about the lowest key and
 821  * level of the tree block are required. These information are stored in
 822  * tree block info structure.
 823  */
 824
 825 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 826 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 827                                   struct btrfs_root *root,
 828                                   struct btrfs_path *path,
 829                                   u64 owner, u32 extra_size)
 830 {
 831         struct btrfs_extent_item *item;
 832         struct btrfs_extent_item_v0 *ei0;
 833         struct btrfs_extent_ref_v0 *ref0;
 834         struct btrfs_tree_block_info *bi;
 835         struct extent_buffer *leaf;
 836         struct btrfs_key key;
 837         struct btrfs_key found_key;
 838         u32 new_size = sizeof(*item);
 839         u64 refs;
 840         int ret;
 841
 842         leaf = path->nodes[0];
 843         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 844
 845         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 846         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 847                              struct btrfs_extent_item_v0);
 848         refs = btrfs_extent_refs_v0(leaf, ei0);
 849
 850         if (owner == (u64)-1) {
 851                 while (1) {
 852                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 853                                 ret = btrfs_next_leaf(root, path);
 854                                 if (ret < 0)
 855                                         return ret;
 856                                 BUG_ON(ret > 0);
 857                                 leaf = path->nodes[0];
 858                         }
 859                         btrfs_item_key_to_cpu(leaf, &found_key,
 860                                               path->slots[0]);
 861                         BUG_ON(key.objectid != found_key.objectid);
 862                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 863                                 path->slots[0]++;
 864                                 continue;
 865                         }
 866                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 867                                               struct btrfs_extent_ref_v0);
 868                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 869                         break;
 870                 }
 871         }
 872         btrfs_release_path(root, path);
 873
 874         if (owner < BTRFS_FIRST_FREE_OBJECTID)
 875                 new_size += sizeof(*bi);
 876
 877         new_size -= sizeof(*ei0);
 878         ret = btrfs_search_slot(trans, root, &key, path,
 879                                 new_size + extra_size, 1);
 880         if (ret < 0)
 881                 return ret;
 882         BUG_ON(ret);
 883
 884         ret = btrfs_extend_item(trans, root, path, new_size);
 885         BUG_ON(ret);
 886
 887         leaf = path->nodes[0];
 888         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 889         btrfs_set_extent_refs(leaf, item, refs);
 890         /* FIXME: get real generation */
 891         btrfs_set_extent_generation(leaf, item, 0);
 892         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 893                 btrfs_set_extent_flags(leaf, item,
 894                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
 895                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
 896                 bi = (struct btrfs_tree_block_info *)(item + 1);
 897                 /* FIXME: get first key of the block */
 898                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
 899                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
 900         } else {
 901                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
 902         }
 903         btrfs_mark_buffer_dirty(leaf);
 904         return 0;
 905 }
 906 #endif
 907
 908 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 909 {
 910         u32 high_crc = ~(u32)0;
 911         u32 low_crc = ~(u32)0;
 912         __le64 lenum;
 913
 914         lenum = cpu_to_le64(root_objectid);
 915         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
 916         lenum = cpu_to_le64(owner);
 917         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 918         lenum = cpu_to_le64(offset);
 919         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 920
 921         return ((u64)high_crc << 31) ^ (u64)low_crc;
 922 }
 923
 924 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 925                                      struct btrfs_extent_data_ref *ref)
 926 {
 927         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 928                                     btrfs_extent_data_ref_objectid(leaf, ref),
 929                                     btrfs_extent_data_ref_offset(leaf, ref));
 930 }
 931
 932 static int match_extent_data_ref(struct extent_buffer *leaf,
 933                                  struct btrfs_extent_data_ref *ref,
 934                                  u64 root_objectid, u64 owner, u64 offset)
 935 {
 936         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
 937             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
 938             btrfs_extent_data_ref_offset(leaf, ref) != offset)
 939                 return 0;
 940         return 1;
 941 }
 942
 943 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 944                                            struct btrfs_root *root,
 945                                            struct btrfs_path *path,
 946                                            u64 bytenr, u64 parent,
 947                                            u64 root_objectid,
 948                                            u64 owner, u64 offset)
 949 {
 950         struct btrfs_key key;
 951         struct btrfs_extent_data_ref *ref;
 952         struct extent_buffer *leaf;
 953         u32 nritems;
 954         int ret;
 955         int recow;
 956         int err = -ENOENT;
 957
 958         key.objectid = bytenr;
 959         if (parent) {
 960                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 961                 key.offset = parent;
 962         } else {
 963                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 964                 key.offset = hash_extent_data_ref(root_objectid,
 965                                                   owner, offset);
 966         }
 967 again:
 968         recow = 0;
 969         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 970         if (ret < 0) {
 971                 err = ret;
 972                 goto fail;
 973         }
 974
 975         if (parent) {
 976                 if (!ret)
 977                         return 0;
 978 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 979                 key.type = BTRFS_EXTENT_REF_V0_KEY;
 980                 btrfs_release_path(root, path);
 981                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 982                 if (ret < 0) {
 983                         err = ret;
 984                         goto fail;
 985                 }
 986                 if (!ret)
 987                         return 0;
 988 #endif
 989                 goto fail;
 990         }
 991
 992         leaf = path->nodes[0];
 993         nritems = btrfs_header_nritems(leaf);
 994         while (1) {
 995                 if (path->slots[0] >= nritems) {
 996                         ret = btrfs_next_leaf(root, path);
 997                         if (ret < 0)
 998                                 err = ret;
 999                         if (ret)
1000                                 goto fail;
1001
1002                         leaf = path->nodes[0];
1003                         nritems = btrfs_header_nritems(leaf);
1004                         recow = 1;
1005                 }
1006
1007                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1008                 if (key.objectid != bytenr ||
1009                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1010                         goto fail;
1011
1012                 ref = btrfs_item_ptr(leaf, path->slots[0],
1013                                      struct btrfs_extent_data_ref);
1014
1015                 if (match_extent_data_ref(leaf, ref, root_objectid,
1016                                           owner, offset)) {
1017                         if (recow) {
1018                                 btrfs_release_path(root, path);
1019                                 goto again;
1020                         }
1021                         err = 0;
1022                         break;
1023                 }
1024                 path->slots[0]++;
1025         }
1026 fail:
1027         return err;
1028 }
1029
1030 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1031                                            struct btrfs_root *root,
1032                                            struct btrfs_path *path,
1033                                            u64 bytenr, u64 parent,
1034                                            u64 root_objectid, u64 owner,
1035                                            u64 offset, int refs_to_add)
1036 {
1037         struct btrfs_key key;
1038         struct extent_buffer *leaf;
1039         u32 size;
1040         u32 num_refs;
1041         int ret;
1042
1043         key.objectid = bytenr;
1044         if (parent) {
1045                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1046                 key.offset = parent;
1047                 size = sizeof(struct btrfs_shared_data_ref);
1048         } else {
1049                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1050                 key.offset = hash_extent_data_ref(root_objectid,
1051                                                   owner, offset);
1052                 size = sizeof(struct btrfs_extent_data_ref);
1053         }
1054
1055         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1056         if (ret && ret != -EEXIST)
1057                 goto fail;
1058
1059         leaf = path->nodes[0];
1060         if (parent) {
1061                 struct btrfs_shared_data_ref *ref;
1062                 ref = btrfs_item_ptr(leaf, path->slots[0],
1063                                      struct btrfs_shared_data_ref);
1064                 if (ret == 0) {
1065                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1066                 } else {
1067                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1068                         num_refs += refs_to_add;
1069                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1070                 }
1071         } else {
1072                 struct btrfs_extent_data_ref *ref;
1073                 while (ret == -EEXIST) {
1074                         ref = btrfs_item_ptr(leaf, path->slots[0],
1075                                              struct btrfs_extent_data_ref);
1076                         if (match_extent_data_ref(leaf, ref, root_objectid,
1077                                                   owner, offset))
1078                                 break;
1079                         btrfs_release_path(root, path);
1080                         key.offset++;
1081                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1082                                                       size);
1083                         if (ret && ret != -EEXIST)
1084                                 goto fail;
1085
1086                         leaf = path->nodes[0];
1087                 }
1088                 ref = btrfs_item_ptr(leaf, path->slots[0],
1089                                      struct btrfs_extent_data_ref);
1090                 if (ret == 0) {
1091                         btrfs_set_extent_data_ref_root(leaf, ref,
1092                                                        root_objectid);
1093                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1094                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1095                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1096                 } else {
1097                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1098                         num_refs += refs_to_add;
1099                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1100                 }
1101         }
1102         btrfs_mark_buffer_dirty(leaf);
1103         ret = 0;
1104 fail:
1105         btrfs_release_path(root, path);
1106         return ret;
1107 }
1108
1109 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1110                                            struct btrfs_root *root,
1111                                            struct btrfs_path *path,
1112                                            int refs_to_drop)
1113 {
1114         struct btrfs_key key;
1115         struct btrfs_extent_data_ref *ref1 = NULL;
1116         struct btrfs_shared_data_ref *ref2 = NULL;
1117         struct extent_buffer *leaf;
1118         u32 num_refs = 0;
1119         int ret = 0;
1120
1121         leaf = path->nodes[0];
1122         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1123
1124         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1125                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1126                                       struct btrfs_extent_data_ref);
1127                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1128         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1129                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1130                                       struct btrfs_shared_data_ref);
1131                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1132 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1133         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1134                 struct btrfs_extent_ref_v0 *ref0;
1135                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1136                                       struct btrfs_extent_ref_v0);
1137                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1138 #endif
1139         } else {
1140                 BUG();
1141         }
1142
1143         BUG_ON(num_refs < refs_to_drop);
1144         num_refs -= refs_to_drop;
1145
1146         if (num_refs == 0) {
1147                 ret = btrfs_del_item(trans, root, path);
1148         } else {
1149                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1150                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1151                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1152                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1153 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1154                 else {
1155                         struct btrfs_extent_ref_v0 *ref0;
1156                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1157                                         struct btrfs_extent_ref_v0);
1158                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1159                 }
1160 #endif
1161                 btrfs_mark_buffer_dirty(leaf);
1162         }
1163         return ret;
1164 }
1165
1166 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1167                                           struct btrfs_path *path,
1168                                           struct btrfs_extent_inline_ref *iref)
1169 {
1170         struct btrfs_key key;
1171         struct extent_buffer *leaf;
1172         struct btrfs_extent_data_ref *ref1;
1173         struct btrfs_shared_data_ref *ref2;
1174         u32 num_refs = 0;
1175
1176         leaf = path->nodes[0];
1177         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1178         if (iref) {
1179                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1180                     BTRFS_EXTENT_DATA_REF_KEY) {
1181                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1182                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1183                 } else {
1184                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1185                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1186                 }
1187         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1188                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1189                                       struct btrfs_extent_data_ref);
1190                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1191         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1192                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1193                                       struct btrfs_shared_data_ref);
1194                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1195 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1196         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1197                 struct btrfs_extent_ref_v0 *ref0;
1198                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1199                                       struct btrfs_extent_ref_v0);
1200                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1201 #endif
1202         } else {
1203                 WARN_ON(1);
1204         }
1205         return num_refs;
1206 }
1207
1208 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1209                                           struct btrfs_root *root,
1210                                           struct btrfs_path *path,
1211                                           u64 bytenr, u64 parent,
1212                                           u64 root_objectid)
1213 {
1214         struct btrfs_key key;
1215         int ret;
1216
1217         key.objectid = bytenr;
1218         if (parent) {
1219                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1220                 key.offset = parent;
1221         } else {
1222                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1223                 key.offset = root_objectid;
1224         }
1225
1226         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1227         if (ret > 0)
1228                 ret = -ENOENT;
1229 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1230         if (ret == -ENOENT && parent) {
1231                 btrfs_release_path(root, path);
1232                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1233                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1234                 if (ret > 0)
1235                         ret = -ENOENT;
1236         }
1237 #endif
1238         return ret;
1239 }
1240
1241 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1242                                           struct btrfs_root *root,
1243                                           struct btrfs_path *path,
1244                                           u64 bytenr, u64 parent,
1245                                           u64 root_objectid)
1246 {
1247         struct btrfs_key key;
1248         int ret;
1249
1250         key.objectid = bytenr;
1251         if (parent) {
1252                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1253                 key.offset = parent;
1254         } else {
1255                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1256                 key.offset = root_objectid;
1257         }
1258
1259         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1260         btrfs_release_path(root, path);
1261         return ret;
1262 }
1263
1264 static inline int extent_ref_type(u64 parent, u64 owner)
1265 {
1266         int type;
1267         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1268                 if (parent > 0)
1269                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1270                 else
1271                         type = BTRFS_TREE_BLOCK_REF_KEY;
1272         } else {
1273                 if (parent > 0)
1274                         type = BTRFS_SHARED_DATA_REF_KEY;
1275                 else
1276                         type = BTRFS_EXTENT_DATA_REF_KEY;
1277         }
1278         return type;
1279 }
1280
1281 static int find_next_key(struct btrfs_path *path, int level,
1282                          struct btrfs_key *key)
1283
1284 {
1285         for (; level < BTRFS_MAX_LEVEL; level++) {
1286                 if (!path->nodes[level])
1287                         break;
1288                 if (path->slots[level] + 1 >=
1289                     btrfs_header_nritems(path->nodes[level]))
1290                         continue;
1291                 if (level == 0)
1292                         btrfs_item_key_to_cpu(path->nodes[level], key,
1293                                               path->slots[level] + 1);
1294                 else
1295                         btrfs_node_key_to_cpu(path->nodes[level], key,
1296                                               path->slots[level] + 1);
1297                 return 0;
1298         }
1299         return 1;
1300 }
1301
1302 /*
1303  * look for inline back ref. if back ref is found, *ref_ret is set
1304  * to the address of inline back ref, and 0 is returned.
1305  *
1306  * if back ref isn't found, *ref_ret is set to the address where it
1307  * should be inserted, and -ENOENT is returned.
1308  *
1309  * if insert is true and there are too many inline back refs, the path
1310  * points to the extent item, and -EAGAIN is returned.
1311  *
1312  * NOTE: inline back refs are ordered in the same way that back ref
1313  *       items in the tree are ordered.
1314  */
1315 static noinline_for_stack
1316 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1317                                  struct btrfs_root *root,
1318                                  struct btrfs_path *path,
1319                                  struct btrfs_extent_inline_ref **ref_ret,
1320                                  u64 bytenr, u64 num_bytes,
1321                                  u64 parent, u64 root_objectid,
1322                                  u64 owner, u64 offset, int insert)
1323 {
1324         struct btrfs_key key;
1325         struct extent_buffer *leaf;
1326         struct btrfs_extent_item *ei;
1327         struct btrfs_extent_inline_ref *iref;
1328         u64 flags;
1329         u64 item_size;
1330         unsigned long ptr;
1331         unsigned long end;
1332         int extra_size;
1333         int type;
1334         int want;
1335         int ret;
1336         int err = 0;
1337
1338         key.objectid = bytenr;
1339         key.type = BTRFS_EXTENT_ITEM_KEY;
1340         key.offset = num_bytes;
1341
1342         want = extent_ref_type(parent, owner);
1343         if (insert) {
1344                 extra_size = btrfs_extent_inline_ref_size(want);
1345                 path->keep_locks = 1;
1346         } else
1347                 extra_size = -1;
1348         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1349         if (ret < 0) {
1350                 err = ret;
1351                 goto out;
1352         }
1353         BUG_ON(ret);
1354
1355         leaf = path->nodes[0];
1356         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1357 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1358         if (item_size < sizeof(*ei)) {
1359                 if (!insert) {
1360                         err = -ENOENT;
1361                         goto out;
1362                 }
1363                 ret = convert_extent_item_v0(trans, root, path, owner,
1364                                              extra_size);
1365                 if (ret < 0) {
1366                         err = ret;
1367                         goto out;
1368                 }
1369                 leaf = path->nodes[0];
1370                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1371         }
1372 #endif
1373         BUG_ON(item_size < sizeof(*ei));
1374
1375         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1376         flags = btrfs_extent_flags(leaf, ei);
1377
1378         ptr = (unsigned long)(ei + 1);
1379         end = (unsigned long)ei + item_size;
1380
1381         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1382                 ptr += sizeof(struct btrfs_tree_block_info);
1383                 BUG_ON(ptr > end);
1384         } else {
1385                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1386         }
1387
1388         err = -ENOENT;
1389         while (1) {
1390                 if (ptr >= end) {
1391                         WARN_ON(ptr > end);
1392                         break;
1393                 }
1394                 iref = (struct btrfs_extent_inline_ref *)ptr;
1395                 type = btrfs_extent_inline_ref_type(leaf, iref);
1396                 if (want < type)
1397                         break;
1398                 if (want > type) {
1399                         ptr += btrfs_extent_inline_ref_size(type);
1400                         continue;
1401                 }
1402
1403                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1404                         struct btrfs_extent_data_ref *dref;
1405                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1406                         if (match_extent_data_ref(leaf, dref, root_objectid,
1407                                                   owner, offset)) {
1408                                 err = 0;
1409                                 break;
1410                         }
1411                         if (hash_extent_data_ref_item(leaf, dref) <
1412                             hash_extent_data_ref(root_objectid, owner, offset))
1413                                 break;
1414                 } else {
1415                         u64 ref_offset;
1416                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1417                         if (parent > 0) {
1418                                 if (parent == ref_offset) {
1419                                         err = 0;
1420                                         break;
1421                                 }
1422                                 if (ref_offset < parent)
1423                                         break;
1424                         } else {
1425                                 if (root_objectid == ref_offset) {
1426                                         err = 0;
1427                                         break;
1428                                 }
1429                                 if (ref_offset < root_objectid)
1430                                         break;
1431                         }
1432                 }
1433                 ptr += btrfs_extent_inline_ref_size(type);
1434         }
1435         if (err == -ENOENT && insert) {
1436                 if (item_size + extra_size >=
1437                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1438                         err = -EAGAIN;
1439                         goto out;
1440                 }
1441                 /*
1442                  * To add new inline back ref, we have to make sure
1443                  * there is no corresponding back ref item.
1444                  * For simplicity, we just do not add new inline back
1445                  * ref if there is any kind of item for this block
1446                  */
1447                 if (find_next_key(path, 0, &key) == 0 &&
1448                     key.objectid == bytenr &&
1449                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1450                         err = -EAGAIN;
1451                         goto out;
1452                 }
1453         }
1454         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1455 out:
1456         if (insert) {
1457                 path->keep_locks = 0;
1458                 btrfs_unlock_up_safe(path, 1);
1459         }
1460         return err;
1461 }
1462
1463 /*
1464  * helper to add new inline back ref
1465  */
1466 static noinline_for_stack
1467 int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1468                                 struct btrfs_root *root,
1469                                 struct btrfs_path *path,
1470                                 struct btrfs_extent_inline_ref *iref,
1471                                 u64 parent, u64 root_objectid,
1472                                 u64 owner, u64 offset, int refs_to_add,
1473                                 struct btrfs_delayed_extent_op *extent_op)
1474 {
1475         struct extent_buffer *leaf;
1476         struct btrfs_extent_item *ei;
1477         unsigned long ptr;
1478         unsigned long end;
1479         unsigned long item_offset;
1480         u64 refs;
1481         int size;
1482         int type;
1483         int ret;
1484
1485         leaf = path->nodes[0];
1486         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1487         item_offset = (unsigned long)iref - (unsigned long)ei;
1488
1489         type = extent_ref_type(parent, owner);
1490         size = btrfs_extent_inline_ref_size(type);
1491
1492         ret = btrfs_extend_item(trans, root, path, size);
1493         BUG_ON(ret);
1494
1495         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1496         refs = btrfs_extent_refs(leaf, ei);
1497         refs += refs_to_add;
1498         btrfs_set_extent_refs(leaf, ei, refs);
1499         if (extent_op)
1500                 __run_delayed_extent_op(extent_op, leaf, ei);
1501
1502         ptr = (unsigned long)ei + item_offset;
1503         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1504         if (ptr < end - size)
1505                 memmove_extent_buffer(leaf, ptr + size, ptr,
1506                                       end - size - ptr);
1507
1508         iref = (struct btrfs_extent_inline_ref *)ptr;
1509         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1510         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1511                 struct btrfs_extent_data_ref *dref;
1512                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1513                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1514                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1515                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1516                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1517         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1518                 struct btrfs_shared_data_ref *sref;
1519                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1520                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1521                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1522         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1523                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1524         } else {
1525                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1526         }
1527         btrfs_mark_buffer_dirty(leaf);
1528         return 0;
1529 }
1530
1531 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1532                                  struct btrfs_root *root,
1533                                  struct btrfs_path *path,
1534                                  struct btrfs_extent_inline_ref **ref_ret,
1535                                  u64 bytenr, u64 num_bytes, u64 parent,
1536                                  u64 root_objectid, u64 owner, u64 offset)
1537 {
1538         int ret;
1539
1540         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1541                                            bytenr, num_bytes, parent,
1542                                            root_objectid, owner, offset, 0);
1543         if (ret != -ENOENT)
1544                 return ret;
1545
1546         btrfs_release_path(root, path);
1547         *ref_ret = NULL;
1548
1549         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1550                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1551                                             root_objectid);
1552         } else {
1553                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1554                                              root_objectid, owner, offset);
1555         }
1556         return ret;
1557 }
1558
1559 /*
1560  * helper to update/remove inline back ref
1561  */
1562 static noinline_for_stack
1563 int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1564                                  struct btrfs_root *root,
1565                                  struct btrfs_path *path,
1566                                  struct btrfs_extent_inline_ref *iref,
1567                                  int refs_to_mod,
1568                                  struct btrfs_delayed_extent_op *extent_op)
1569 {
1570         struct extent_buffer *leaf;
1571         struct btrfs_extent_item *ei;
1572         struct btrfs_extent_data_ref *dref = NULL;
1573         struct btrfs_shared_data_ref *sref = NULL;
1574         unsigned long ptr;
1575         unsigned long end;
1576         u32 item_size;
1577         int size;
1578         int type;
1579         int ret;
1580         u64 refs;
1581
1582         leaf = path->nodes[0];
1583         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1584         refs = btrfs_extent_refs(leaf, ei);
1585         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1586         refs += refs_to_mod;
1587         btrfs_set_extent_refs(leaf, ei, refs);
1588         if (extent_op)
1589                 __run_delayed_extent_op(extent_op, leaf, ei);
1590
1591         type = btrfs_extent_inline_ref_type(leaf, iref);
1592
1593         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1594                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1595                 refs = btrfs_extent_data_ref_count(leaf, dref);
1596         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1597                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1598                 refs = btrfs_shared_data_ref_count(leaf, sref);
1599         } else {
1600                 refs = 1;
1601                 BUG_ON(refs_to_mod != -1);
1602         }
1603
1604         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1605         refs += refs_to_mod;
1606
1607         if (refs > 0) {
1608                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1609                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1610                 else
1611                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1612         } else {
1613                 size =  btrfs_extent_inline_ref_size(type);
1614                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1615                 ptr = (unsigned long)iref;
1616                 end = (unsigned long)ei + item_size;
1617                 if (ptr + size < end)
1618                         memmove_extent_buffer(leaf, ptr, ptr + size,
1619                                               end - ptr - size);
1620                 item_size -= size;
1621                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1622                 BUG_ON(ret);
1623         }
1624         btrfs_mark_buffer_dirty(leaf);
1625         return 0;
1626 }
1627
1628 static noinline_for_stack
1629 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1630                                  struct btrfs_root *root,
1631                                  struct btrfs_path *path,
1632                                  u64 bytenr, u64 num_bytes, u64 parent,
1633                                  u64 root_objectid, u64 owner,
1634                                  u64 offset, int refs_to_add,
1635                                  struct btrfs_delayed_extent_op *extent_op)
1636 {
1637         struct btrfs_extent_inline_ref *iref;
1638         int ret;
1639
1640         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1641                                            bytenr, num_bytes, parent,
1642                                            root_objectid, owner, offset, 1);
1643         if (ret == 0) {
1644                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1645                 ret = update_inline_extent_backref(trans, root, path, iref,
1646                                                    refs_to_add, extent_op);
1647         } else if (ret == -ENOENT) {
1648                 ret = setup_inline_extent_backref(trans, root, path, iref,
1649                                                   parent, root_objectid,
1650                                                   owner, offset, refs_to_add,
1651                                                   extent_op);
1652         }
1653         return ret;
1654 }
1655
1656 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1657                                  struct btrfs_root *root,
1658                                  struct btrfs_path *path,
1659                                  u64 bytenr, u64 parent, u64 root_objectid,
1660                                  u64 owner, u64 offset, int refs_to_add)
1661 {
1662         int ret;
1663         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1664                 BUG_ON(refs_to_add != 1);
1665                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1666                                             parent, root_objectid);
1667         } else {
1668                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1669                                              parent, root_objectid,
1670                                              owner, offset, refs_to_add);
1671         }
1672         return ret;
1673 }
1674
1675 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1676                                  struct btrfs_root *root,
1677                                  struct btrfs_path *path,
1678                                  struct btrfs_extent_inline_ref *iref,
1679                                  int refs_to_drop, int is_data)
1680 {
1681         int ret;
1682
1683         BUG_ON(!is_data && refs_to_drop != 1);
1684         if (iref) {
1685                 ret = update_inline_extent_backref(trans, root, path, iref,
1686                                                    -refs_to_drop, NULL);
1687         } else if (is_data) {
1688                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1689         } else {
1690                 ret = btrfs_del_item(trans, root, path);
1691         }
1692         return ret;
1693 }
1694
1695 static void btrfs_issue_discard(struct block_device *bdev,
1696                                 u64 start, u64 len)
1697 {
1698         blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL,
1699                         BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);
1700 }
1701
1702 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1703                                 u64 num_bytes)
1704 {
1705         int ret;
1706         u64 map_length = num_bytes;
1707         struct btrfs_multi_bio *multi = NULL;
1708
1709         if (!btrfs_test_opt(root, DISCARD))
1710                 return 0;
1711
1712         /* Tell the block device(s) that the sectors can be discarded */
1713         ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
1714                               bytenr, &map_length, &multi, 0);
1715         if (!ret) {
1716                 struct btrfs_bio_stripe *stripe = multi->stripes;
1717                 int i;
1718
1719                 if (map_length > num_bytes)
1720                         map_length = num_bytes;
1721
1722                 for (i = 0; i < multi->num_stripes; i++, stripe++) {
1723                         btrfs_issue_discard(stripe->dev->bdev,
1724                                             stripe->physical,
1725                                             map_length);
1726                 }
1727                 kfree(multi);
1728         }
1729
1730         return ret;
1731 }
1732
1733 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1734                          struct btrfs_root *root,
1735                          u64 bytenr, u64 num_bytes, u64 parent,
1736                          u64 root_objectid, u64 owner, u64 offset)
1737 {
1738         int ret;
1739         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1740                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1741
1742         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1743                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
1744                                         parent, root_objectid, (int)owner,
1745                                         BTRFS_ADD_DELAYED_REF, NULL);
1746         } else {
1747                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
1748                                         parent, root_objectid, owner, offset,
1749                                         BTRFS_ADD_DELAYED_REF, NULL);
1750         }
1751         return ret;
1752 }
1753
1754 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1755                                   struct btrfs_root *root,
1756                                   u64 bytenr, u64 num_bytes,
1757                                   u64 parent, u64 root_objectid,
1758                                   u64 owner, u64 offset, int refs_to_add,
1759                                   struct btrfs_delayed_extent_op *extent_op)
1760 {
1761         struct btrfs_path *path;
1762         struct extent_buffer *leaf;
1763         struct btrfs_extent_item *item;
1764         u64 refs;
1765         int ret;
1766         int err = 0;
1767
1768         path = btrfs_alloc_path();
1769         if (!path)
1770                 return -ENOMEM;
1771
1772         path->reada = 1;
1773         path->leave_spinning = 1;
1774         /* this will setup the path even if it fails to insert the back ref */
1775         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1776                                            path, bytenr, num_bytes, parent,
1777                                            root_objectid, owner, offset,
1778                                            refs_to_add, extent_op);
1779         if (ret == 0)
1780                 goto out;
1781
1782         if (ret != -EAGAIN) {
1783                 err = ret;
1784                 goto out;
1785         }
1786
1787         leaf = path->nodes[0];
1788         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1789         refs = btrfs_extent_refs(leaf, item);
1790         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1791         if (extent_op)
1792                 __run_delayed_extent_op(extent_op, leaf, item);
1793
1794         btrfs_mark_buffer_dirty(leaf);
1795         btrfs_release_path(root->fs_info->extent_root, path);
1796
1797         path->reada = 1;
1798         path->leave_spinning = 1;
1799
1800         /* now insert the actual backref */
1801         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1802                                     path, bytenr, parent, root_objectid,
1803                                     owner, offset, refs_to_add);
1804         BUG_ON(ret);
1805 out:
1806         btrfs_free_path(path);
1807         return err;
1808 }
1809
1810 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1811                                 struct btrfs_root *root,
1812                                 struct btrfs_delayed_ref_node *node,
1813                                 struct btrfs_delayed_extent_op *extent_op,
1814                                 int insert_reserved)
1815 {
1816         int ret = 0;
1817         struct btrfs_delayed_data_ref *ref;
1818         struct btrfs_key ins;
1819         u64 parent = 0;
1820         u64 ref_root = 0;
1821         u64 flags = 0;
1822
1823         ins.objectid = node->bytenr;
1824         ins.offset = node->num_bytes;
1825         ins.type = BTRFS_EXTENT_ITEM_KEY;
1826
1827         ref = btrfs_delayed_node_to_data_ref(node);
1828         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1829                 parent = ref->parent;
1830         else
1831                 ref_root = ref->root;
1832
1833         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1834                 if (extent_op) {
1835                         BUG_ON(extent_op->update_key);
1836                         flags |= extent_op->flags_to_set;
1837                 }
1838                 ret = alloc_reserved_file_extent(trans, root,
1839                                                  parent, ref_root, flags,
1840                                                  ref->objectid, ref->offset,
1841                                                  &ins, node->ref_mod);
1842         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1843                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1844                                              node->num_bytes, parent,
1845                                              ref_root, ref->objectid,
1846                                              ref->offset, node->ref_mod,
1847                                              extent_op);
1848         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1849                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1850                                           node->num_bytes, parent,
1851                                           ref_root, ref->objectid,
1852                                           ref->offset, node->ref_mod,
1853                                           extent_op);
1854         } else {
1855                 BUG();
1856         }
1857         return ret;
1858 }
1859
1860 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1861                                     struct extent_buffer *leaf,
1862                                     struct btrfs_extent_item *ei)
1863 {
1864         u64 flags = btrfs_extent_flags(leaf, ei);
1865         if (extent_op->update_flags) {
1866                 flags |= extent_op->flags_to_set;
1867                 btrfs_set_extent_flags(leaf, ei, flags);
1868         }
1869
1870         if (extent_op->update_key) {
1871                 struct btrfs_tree_block_info *bi;
1872                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1873                 bi = (struct btrfs_tree_block_info *)(ei + 1);
1874                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1875         }
1876 }
1877
1878 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1879                                  struct btrfs_root *root,
1880                                  struct btrfs_delayed_ref_node *node,
1881                                  struct btrfs_delayed_extent_op *extent_op)
1882 {
1883         struct btrfs_key key;
1884         struct btrfs_path *path;
1885         struct btrfs_extent_item *ei;
1886         struct extent_buffer *leaf;
1887         u32 item_size;
1888         int ret;
1889         int err = 0;
1890
1891         path = btrfs_alloc_path();
1892         if (!path)
1893                 return -ENOMEM;
1894
1895         key.objectid = node->bytenr;
1896         key.type = BTRFS_EXTENT_ITEM_KEY;
1897         key.offset = node->num_bytes;
1898
1899         path->reada = 1;
1900         path->leave_spinning = 1;
1901         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
1902                                 path, 0, 1);
1903         if (ret < 0) {
1904                 err = ret;
1905                 goto out;
1906         }
1907         if (ret > 0) {
1908                 err = -EIO;
1909                 goto out;
1910         }
1911
1912         leaf = path->nodes[0];
1913         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1914 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1915         if (item_size < sizeof(*ei)) {
1916                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
1917                                              path, (u64)-1, 0);
1918                 if (ret < 0) {
1919                         err = ret;
1920                         goto out;
1921                 }
1922                 leaf = path->nodes[0];
1923                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1924         }
1925 #endif
1926         BUG_ON(item_size < sizeof(*ei));
1927         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1928         __run_delayed_extent_op(extent_op, leaf, ei);
1929
1930         btrfs_mark_buffer_dirty(leaf);
1931 out:
1932         btrfs_free_path(path);
1933         return err;
1934 }
1935
1936 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
1937                                 struct btrfs_root *root,
1938                                 struct btrfs_delayed_ref_node *node,
1939                                 struct btrfs_delayed_extent_op *extent_op,
1940                                 int insert_reserved)
1941 {
1942         int ret = 0;
1943         struct btrfs_delayed_tree_ref *ref;
1944         struct btrfs_key ins;
1945         u64 parent = 0;
1946         u64 ref_root = 0;
1947
1948         ins.objectid = node->bytenr;
1949         ins.offset = node->num_bytes;
1950         ins.type = BTRFS_EXTENT_ITEM_KEY;
1951
1952         ref = btrfs_delayed_node_to_tree_ref(node);
1953         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1954                 parent = ref->parent;
1955         else
1956                 ref_root = ref->root;
1957
1958         BUG_ON(node->ref_mod != 1);
1959         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1960                 BUG_ON(!extent_op || !extent_op->update_flags ||
1961                        !extent_op->update_key);
1962                 ret = alloc_reserved_tree_block(trans, root,
1963                                                 parent, ref_root,
1964                                                 extent_op->flags_to_set,
1965                                                 &extent_op->key,
1966                                                 ref->level, &ins);
1967         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1968                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1969                                              node->num_bytes, parent, ref_root,
1970                                              ref->level, 0, 1, extent_op);
1971         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1972                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1973                                           node->num_bytes, parent, ref_root,
1974                                           ref->level, 0, 1, extent_op);
1975         } else {
1976                 BUG();
1977         }
1978         return ret;
1979 }
1980
1981 /* helper function to actually process a single delayed ref entry */
1982 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
1983                                struct btrfs_root *root,
1984                                struct btrfs_delayed_ref_node *node,
1985                                struct btrfs_delayed_extent_op *extent_op,
1986                                int insert_reserved)
1987 {
1988         int ret;
1989         if (btrfs_delayed_ref_is_head(node)) {
1990                 struct btrfs_delayed_ref_head *head;
1991                 /*
1992                  * we've hit the end of the chain and we were supposed
1993                  * to insert this extent into the tree.  But, it got
1994                  * deleted before we ever needed to insert it, so all
1995                  * we have to do is clean up the accounting
1996                  */
1997                 BUG_ON(extent_op);
1998                 head = btrfs_delayed_node_to_head(node);
1999                 if (insert_reserved) {
2000                         btrfs_pin_extent(root, node->bytenr,
2001                                          node->num_bytes, 1);
2002                         if (head->is_data) {
2003                                 ret = btrfs_del_csums(trans, root,
2004                                                       node->bytenr,
2005                                                       node->num_bytes);
2006                                 BUG_ON(ret);
2007                         }
2008                 }
2009                 mutex_unlock(&head->mutex);
2010                 return 0;
2011         }
2012
2013         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2014             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2015                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2016                                            insert_reserved);
2017         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2018                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2019                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2020                                            insert_reserved);
2021         else
2022                 BUG();
2023         return ret;
2024 }
2025
2026 static noinline struct btrfs_delayed_ref_node *
2027 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2028 {
2029         struct rb_node *node;
2030         struct btrfs_delayed_ref_node *ref;
2031         int action = BTRFS_ADD_DELAYED_REF;
2032 again:
2033         /*
2034          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2035          * this prevents ref count from going down to zero when
2036          * there still are pending delayed ref.
2037          */
2038         node = rb_prev(&head->node.rb_node);
2039         while (1) {
2040                 if (!node)
2041                         break;
2042                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2043                                 rb_node);
2044                 if (ref->bytenr != head->node.bytenr)
2045                         break;
2046                 if (ref->action == action)
2047                         return ref;
2048                 node = rb_prev(node);
2049         }
2050         if (action == BTRFS_ADD_DELAYED_REF) {
2051                 action = BTRFS_DROP_DELAYED_REF;
2052                 goto again;
2053         }
2054         return NULL;
2055 }
2056
2057 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2058                                        struct btrfs_root *root,
2059                                        struct list_head *cluster)
2060 {
2061         struct btrfs_delayed_ref_root *delayed_refs;
2062         struct btrfs_delayed_ref_node *ref;
2063         struct btrfs_delayed_ref_head *locked_ref = NULL;
2064         struct btrfs_delayed_extent_op *extent_op;
2065         int ret;
2066         int count = 0;
2067         int must_insert_reserved = 0;
2068
2069         delayed_refs = &trans->transaction->delayed_refs;
2070         while (1) {
2071                 if (!locked_ref) {
2072                         /* pick a new head ref from the cluster list */
2073                         if (list_empty(cluster))
2074                                 break;
2075
2076                         locked_ref = list_entry(cluster->next,
2077                                      struct btrfs_delayed_ref_head, cluster);
2078
2079                         /* grab the lock that says we are going to process
2080                          * all the refs for this head */
2081                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2082
2083                         /*
2084                          * we may have dropped the spin lock to get the head
2085                          * mutex lock, and that might have given someone else
2086                          * time to free the head.  If that's true, it has been
2087                          * removed from our list and we can move on.
2088                          */
2089                         if (ret == -EAGAIN) {
2090                                 locked_ref = NULL;
2091                                 count++;
2092                                 continue;
2093                         }
2094                 }
2095
2096                 /*
2097                  * record the must insert reserved flag before we
2098                  * drop the spin lock.
2099                  */
2100                 must_insert_reserved = locked_ref->must_insert_reserved;
2101                 locked_ref->must_insert_reserved = 0;
2102
2103                 extent_op = locked_ref->extent_op;
2104                 locked_ref->extent_op = NULL;
2105
2106                 /*
2107                  * locked_ref is the head node, so we have to go one
2108                  * node back for any delayed ref updates
2109                  */
2110                 ref = select_delayed_ref(locked_ref);
2111                 if (!ref) {
2112                         /* All delayed refs have been processed, Go ahead
2113                          * and send the head node to run_one_delayed_ref,
2114                          * so that any accounting fixes can happen
2115                          */
2116                         ref = &locked_ref->node;
2117
2118                         if (extent_op && must_insert_reserved) {
2119                                 kfree(extent_op);
2120                                 extent_op = NULL;
2121                         }
2122
2123                         if (extent_op) {
2124                                 spin_unlock(&delayed_refs->lock);
2125
2126                                 ret = run_delayed_extent_op(trans, root,
2127                                                             ref, extent_op);
2128                                 BUG_ON(ret);
2129                                 kfree(extent_op);
2130
2131                                 cond_resched();
2132                                 spin_lock(&delayed_refs->lock);
2133                                 continue;
2134                         }
2135
2136                         list_del_init(&locked_ref->cluster);
2137                         locked_ref = NULL;
2138                 }
2139
2140                 ref->in_tree = 0;
2141                 rb_erase(&ref->rb_node, &delayed_refs->root);
2142                 delayed_refs->num_entries--;
2143
2144                 spin_unlock(&delayed_refs->lock);
2145
2146                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2147                                           must_insert_reserved);
2148                 BUG_ON(ret);
2149
2150                 btrfs_put_delayed_ref(ref);
2151                 kfree(extent_op);
2152                 count++;
2153
2154                 cond_resched();
2155                 spin_lock(&delayed_refs->lock);
2156         }
2157         return count;
2158 }
2159
2160 /*
2161  * this starts processing the delayed reference count updates and
2162  * extent insertions we have queued up so far.  count can be
2163  * 0, which means to process everything in the tree at the start
2164  * of the run (but not newly added entries), or it can be some target
2165  * number you'd like to process.
2166  */
2167 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2168                            struct btrfs_root *root, unsigned long count)
2169 {
2170         struct rb_node *node;
2171         struct btrfs_delayed_ref_root *delayed_refs;
2172         struct btrfs_delayed_ref_node *ref;
2173         struct list_head cluster;
2174         int ret;
2175         int run_all = count == (unsigned long)-1;
2176         int run_most = 0;
2177
2178         if (root == root->fs_info->extent_root)
2179                 root = root->fs_info->tree_root;
2180
2181         delayed_refs = &trans->transaction->delayed_refs;
2182         INIT_LIST_HEAD(&cluster);
2183 again:
2184         spin_lock(&delayed_refs->lock);
2185         if (count == 0) {
2186                 count = delayed_refs->num_entries * 2;
2187                 run_most = 1;
2188         }
2189         while (1) {
2190                 if (!(run_all || run_most) &&
2191                     delayed_refs->num_heads_ready < 64)
2192                         break;
2193
2194                 /*
2195                  * go find something we can process in the rbtree.  We start at
2196                  * the beginning of the tree, and then build a cluster
2197                  * of refs to process starting at the first one we are able to
2198                  * lock
2199                  */
2200                 ret = btrfs_find_ref_cluster(trans, &cluster,
2201                                              delayed_refs->run_delayed_start);
2202                 if (ret)
2203                         break;
2204
2205                 ret = run_clustered_refs(trans, root, &cluster);
2206                 BUG_ON(ret < 0);
2207
2208                 count -= min_t(unsigned long, ret, count);
2209
2210                 if (count == 0)
2211                         break;
2212         }
2213
2214         if (run_all) {
2215                 node = rb_first(&delayed_refs->root);
2216                 if (!node)
2217                         goto out;
2218                 count = (unsigned long)-1;
2219
2220                 while (node) {
2221                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2222                                        rb_node);
2223                         if (btrfs_delayed_ref_is_head(ref)) {
2224                                 struct btrfs_delayed_ref_head *head;
2225
2226                                 head = btrfs_delayed_node_to_head(ref);
2227                                 atomic_inc(&ref->refs);
2228
2229                                 spin_unlock(&delayed_refs->lock);
2230                                 mutex_lock(&head->mutex);
2231                                 mutex_unlock(&head->mutex);
2232
2233                                 btrfs_put_delayed_ref(ref);
2234                                 cond_resched();
2235                                 goto again;
2236                         }
2237                         node = rb_next(node);
2238                 }
2239                 spin_unlock(&delayed_refs->lock);
2240                 schedule_timeout(1);
2241                 goto again;
2242         }
2243 out:
2244         spin_unlock(&delayed_refs->lock);
2245         return 0;
2246 }
2247
2248 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2249                                 struct btrfs_root *root,
2250                                 u64 bytenr, u64 num_bytes, u64 flags,
2251                                 int is_data)
2252 {
2253         struct btrfs_delayed_extent_op *extent_op;
2254         int ret;
2255
2256         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2257         if (!extent_op)
2258                 return -ENOMEM;
2259
2260         extent_op->flags_to_set = flags;
2261         extent_op->update_flags = 1;
2262         extent_op->update_key = 0;
2263         extent_op->is_data = is_data ? 1 : 0;
2264
2265         ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
2266         if (ret)
2267                 kfree(extent_op);
2268         return ret;
2269 }
2270
2271 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2272                                       struct btrfs_root *root,
2273                                       struct btrfs_path *path,
2274                                       u64 objectid, u64 offset, u64 bytenr)
2275 {
2276         struct btrfs_delayed_ref_head *head;
2277         struct btrfs_delayed_ref_node *ref;
2278         struct btrfs_delayed_data_ref *data_ref;
2279         struct btrfs_delayed_ref_root *delayed_refs;
2280         struct rb_node *node;
2281         int ret = 0;
2282
2283         ret = -ENOENT;
2284         delayed_refs = &trans->transaction->delayed_refs;
2285         spin_lock(&delayed_refs->lock);
2286         head = btrfs_find_delayed_ref_head(trans, bytenr);
2287         if (!head)
2288                 goto out;
2289
2290         if (!mutex_trylock(&head->mutex)) {
2291                 atomic_inc(&head->node.refs);
2292                 spin_unlock(&delayed_refs->lock);
2293
2294                 btrfs_release_path(root->fs_info->extent_root, path);
2295
2296                 mutex_lock(&head->mutex);
2297                 mutex_unlock(&head->mutex);
2298                 btrfs_put_delayed_ref(&head->node);
2299                 return -EAGAIN;
2300         }
2301
2302         node = rb_prev(&head->node.rb_node);
2303         if (!node)
2304                 goto out_unlock;
2305
2306         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2307
2308         if (ref->bytenr != bytenr)
2309                 goto out_unlock;
2310
2311         ret = 1;
2312         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2313                 goto out_unlock;
2314
2315         data_ref = btrfs_delayed_node_to_data_ref(ref);
2316
2317         node = rb_prev(node);
2318         if (node) {
2319                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2320                 if (ref->bytenr == bytenr)
2321                         goto out_unlock;
2322         }
2323
2324         if (data_ref->root != root->root_key.objectid ||
2325             data_ref->objectid != objectid || data_ref->offset != offset)
2326                 goto out_unlock;
2327
2328         ret = 0;
2329 out_unlock:
2330         mutex_unlock(&head->mutex);
2331 out:
2332         spin_unlock(&delayed_refs->lock);
2333         return ret;
2334 }
2335
2336 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2337                                         struct btrfs_root *root,
2338                                         struct btrfs_path *path,
2339                                         u64 objectid, u64 offset, u64 bytenr)
2340 {
2341         struct btrfs_root *extent_root = root->fs_info->extent_root;
2342         struct extent_buffer *leaf;
2343         struct btrfs_extent_data_ref *ref;
2344         struct btrfs_extent_inline_ref *iref;
2345         struct btrfs_extent_item *ei;
2346         struct btrfs_key key;
2347         u32 item_size;
2348         int ret;
2349
2350         key.objectid = bytenr;
2351         key.offset = (u64)-1;
2352         key.type = BTRFS_EXTENT_ITEM_KEY;
2353
2354         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2355         if (ret < 0)
2356                 goto out;
2357         BUG_ON(ret == 0);
2358
2359         ret = -ENOENT;
2360         if (path->slots[0] == 0)
2361                 goto out;
2362
2363         path->slots[0]--;
2364         leaf = path->nodes[0];
2365         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2366
2367         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2368                 goto out;
2369
2370         ret = 1;
2371         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2372 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2373         if (item_size < sizeof(*ei)) {
2374                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2375                 goto out;
2376         }
2377 #endif
2378         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2379
2380         if (item_size != sizeof(*ei) +
2381             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2382                 goto out;
2383
2384         if (btrfs_extent_generation(leaf, ei) <=
2385             btrfs_root_last_snapshot(&root->root_item))
2386                 goto out;
2387
2388         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2389         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2390             BTRFS_EXTENT_DATA_REF_KEY)
2391                 goto out;
2392
2393         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2394         if (btrfs_extent_refs(leaf, ei) !=
2395             btrfs_extent_data_ref_count(leaf, ref) ||
2396             btrfs_extent_data_ref_root(leaf, ref) !=
2397             root->root_key.objectid ||
2398             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2399             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2400                 goto out;
2401
2402         ret = 0;
2403 out:
2404         return ret;
2405 }
2406
2407 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2408                           struct btrfs_root *root,
2409                           u64 objectid, u64 offset, u64 bytenr)
2410 {
2411         struct btrfs_path *path;
2412         int ret;
2413         int ret2;
2414
2415         path = btrfs_alloc_path();
2416         if (!path)
2417                 return -ENOENT;
2418
2419         do {
2420                 ret = check_committed_ref(trans, root, path, objectid,
2421                                           offset, bytenr);
2422                 if (ret && ret != -ENOENT)
2423                         goto out;
2424
2425                 ret2 = check_delayed_ref(trans, root, path, objectid,
2426                                          offset, bytenr);
2427         } while (ret2 == -EAGAIN);
2428
2429         if (ret2 && ret2 != -ENOENT) {
2430                 ret = ret2;
2431                 goto out;
2432         }
2433
2434         if (ret != -ENOENT || ret2 != -ENOENT)
2435                 ret = 0;
2436 out:
2437         btrfs_free_path(path);
2438         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2439                 WARN_ON(ret > 0);
2440         return ret;
2441 }
2442
2443 #if 0
2444 int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2445                     struct extent_buffer *buf, u32 nr_extents)
2446 {
2447         struct btrfs_key key;
2448         struct btrfs_file_extent_item *fi;
2449         u64 root_gen;
2450         u32 nritems;
2451         int i;
2452         int level;
2453         int ret = 0;
2454         int shared = 0;
2455
2456         if (!root->ref_cows)
2457                 return 0;
2458
2459         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2460                 shared = 0;
2461                 root_gen = root->root_key.offset;
2462         } else {
2463                 shared = 1;
2464                 root_gen = trans->transid - 1;
2465         }
2466
2467         level = btrfs_header_level(buf);
2468         nritems = btrfs_header_nritems(buf);
2469
2470         if (level == 0) {
2471                 struct btrfs_leaf_ref *ref;
2472                 struct btrfs_extent_info *info;
2473
2474                 ref = btrfs_alloc_leaf_ref(root, nr_extents);
2475                 if (!ref) {
2476                         ret = -ENOMEM;
2477                         goto out;
2478                 }
2479
2480                 ref->root_gen = root_gen;
2481                 ref->bytenr = buf->start;
2482                 ref->owner = btrfs_header_owner(buf);
2483                 ref->generation = btrfs_header_generation(buf);
2484                 ref->nritems = nr_extents;
2485                 info = ref->extents;
2486
2487                 for (i = 0; nr_extents > 0 && i < nritems; i++) {
2488                         u64 disk_bytenr;
2489                         btrfs_item_key_to_cpu(buf, &key, i);
2490                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2491                                 continue;
2492                         fi = btrfs_item_ptr(buf, i,
2493                                             struct btrfs_file_extent_item);
2494                         if (btrfs_file_extent_type(buf, fi) ==
2495                             BTRFS_FILE_EXTENT_INLINE)
2496                                 continue;
2497                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2498                         if (disk_bytenr == 0)
2499                                 continue;
2500
2501                         info->bytenr = disk_bytenr;
2502                         info->num_bytes =
2503                                 btrfs_file_extent_disk_num_bytes(buf, fi);
2504                         info->objectid = key.objectid;
2505                         info->offset = key.offset;
2506                         info++;
2507                 }
2508
2509                 ret = btrfs_add_leaf_ref(root, ref, shared);
2510                 if (ret == -EEXIST && shared) {
2511                         struct btrfs_leaf_ref *old;
2512                         old = btrfs_lookup_leaf_ref(root, ref->bytenr);
2513                         BUG_ON(!old);
2514                         btrfs_remove_leaf_ref(root, old);
2515                         btrfs_free_leaf_ref(root, old);
2516                         ret = btrfs_add_leaf_ref(root, ref, shared);
2517                 }
2518                 WARN_ON(ret);
2519                 btrfs_free_leaf_ref(root, ref);
2520         }
2521 out:
2522         return ret;
2523 }
2524
2525 /* when a block goes through cow, we update the reference counts of
2526  * everything that block points to.  The internal pointers of the block
2527  * can be in just about any order, and it is likely to have clusters of
2528  * things that are close together and clusters of things that are not.
2529  *
2530  * To help reduce the seeks that come with updating all of these reference
2531  * counts, sort them by byte number before actual updates are done.
2532  *
2533  * struct refsort is used to match byte number to slot in the btree block.
2534  * we sort based on the byte number and then use the slot to actually
2535  * find the item.
2536  *
2537  * struct refsort is smaller than strcut btrfs_item and smaller than
2538  * struct btrfs_key_ptr.  Since we're currently limited to the page size
2539  * for a btree block, there's no way for a kmalloc of refsorts for a
2540  * single node to be bigger than a page.
2541  */
2542 struct refsort {
2543         u64 bytenr;
2544         u32 slot;
2545 };
2546
2547 /*
2548  * for passing into sort()
2549  */
2550 static int refsort_cmp(const void *a_void, const void *b_void)
2551 {
2552         const struct refsort *a = a_void;
2553         const struct refsort *b = b_void;
2554
2555         if (a->bytenr < b->bytenr)
2556                 return -1;
2557         if (a->bytenr > b->bytenr)
2558                 return 1;
2559         return 0;
2560 }
2561 #endif
2562
2563 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2564                            struct btrfs_root *root,
2565                            struct extent_buffer *buf,
2566                            int full_backref, int inc)
2567 {
2568         u64 bytenr;
2569         u64 num_bytes;
2570         u64 parent;
2571         u64 ref_root;
2572         u32 nritems;
2573         struct btrfs_key key;
2574         struct btrfs_file_extent_item *fi;
2575         int i;
2576         int level;
2577         int ret = 0;
2578         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2579                             u64, u64, u64, u64, u64, u64);
2580
2581         ref_root = btrfs_header_owner(buf);
2582         nritems = btrfs_header_nritems(buf);
2583         level = btrfs_header_level(buf);
2584
2585         if (!root->ref_cows && level == 0)
2586                 return 0;
2587
2588         if (inc)
2589                 process_func = btrfs_inc_extent_ref;
2590         else
2591                 process_func = btrfs_free_extent;
2592
2593         if (full_backref)
2594                 parent = buf->start;
2595         else
2596                 parent = 0;
2597
2598         for (i = 0; i < nritems; i++) {
2599                 if (level == 0) {
2600                         btrfs_item_key_to_cpu(buf, &key, i);
2601                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2602                                 continue;
2603                         fi = btrfs_item_ptr(buf, i,
2604                                             struct btrfs_file_extent_item);
2605                         if (btrfs_file_extent_type(buf, fi) ==
2606                             BTRFS_FILE_EXTENT_INLINE)
2607                                 continue;
2608                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2609                         if (bytenr == 0)
2610                                 continue;
2611
2612                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2613                         key.offset -= btrfs_file_extent_offset(buf, fi);
2614                         ret = process_func(trans, root, bytenr, num_bytes,
2615                                            parent, ref_root, key.objectid,
2616                                            key.offset);
2617                         if (ret)
2618                                 goto fail;
2619                 } else {
2620                         bytenr = btrfs_node_blockptr(buf, i);
2621                         num_bytes = btrfs_level_size(root, level - 1);
2622                         ret = process_func(trans, root, bytenr, num_bytes,
2623                                            parent, ref_root, level - 1, 0);
2624                         if (ret)
2625                                 goto fail;
2626                 }
2627         }
2628         return 0;
2629 fail:
2630         BUG();
2631         return ret;
2632 }
2633
2634 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2635                   struct extent_buffer *buf, int full_backref)
2636 {
2637         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2638 }
2639
2640 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2641                   struct extent_buffer *buf, int full_backref)
2642 {
2643         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2644 }
2645
2646 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2647                                  struct btrfs_root *root,
2648                                  struct btrfs_path *path,
2649                                  struct btrfs_block_group_cache *cache)
2650 {
2651         int ret;
2652         struct btrfs_root *extent_root = root->fs_info->extent_root;
2653         unsigned long bi;
2654         struct extent_buffer *leaf;
2655
2656         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2657         if (ret < 0)
2658                 goto fail;
2659         BUG_ON(ret);
2660
2661         leaf = path->nodes[0];
2662         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2663         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2664         btrfs_mark_buffer_dirty(leaf);
2665         btrfs_release_path(extent_root, path);
2666 fail:
2667         if (ret)
2668                 return ret;
2669         return 0;
2670
2671 }
2672
2673 static struct btrfs_block_group_cache *
2674 next_block_group(struct btrfs_root *root,
2675                  struct btrfs_block_group_cache *cache)
2676 {
2677         struct rb_node *node;
2678         spin_lock(&root->fs_info->block_group_cache_lock);
2679         node = rb_next(&cache->cache_node);
2680         btrfs_put_block_group(cache);
2681         if (node) {
2682                 cache = rb_entry(node, struct btrfs_block_group_cache,
2683                                  cache_node);
2684                 btrfs_get_block_group(cache);
2685         } else
2686                 cache = NULL;
2687         spin_unlock(&root->fs_info->block_group_cache_lock);
2688         return cache;
2689 }
2690
2691 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2692                             struct btrfs_trans_handle *trans,
2693                             struct btrfs_path *path)
2694 {
2695         struct btrfs_root *root = block_group->fs_info->tree_root;
2696         struct inode *inode = NULL;
2697         u64 alloc_hint = 0;
2698         int num_pages = 0;
2699         int retries = 0;
2700         int ret = 0;
2701
2702         /*
2703          * If this block group is smaller than 100 megs don't bother caching the
2704          * block group.
2705          */
2706         if (block_group->key.offset < (100 * 1024 * 1024)) {
2707                 spin_lock(&block_group->lock);
2708                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2709                 spin_unlock(&block_group->lock);
2710                 return 0;
2711         }
2712
2713 again:
2714         inode = lookup_free_space_inode(root, block_group, path);
2715         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2716                 ret = PTR_ERR(inode);
2717                 btrfs_release_path(root, path);
2718                 goto out;
2719         }
2720
2721         if (IS_ERR(inode)) {
2722                 BUG_ON(retries);
2723                 retries++;
2724
2725                 if (block_group->ro)
2726                         goto out_free;
2727
2728                 ret = create_free_space_inode(root, trans, block_group, path);
2729                 if (ret)
2730                         goto out_free;
2731                 goto again;
2732         }
2733
2734         /*
2735          * We want to set the generation to 0, that way if anything goes wrong
2736          * from here on out we know not to trust this cache when we load up next
2737          * time.
2738          */
2739         BTRFS_I(inode)->generation = 0;
2740         ret = btrfs_update_inode(trans, root, inode);
2741         WARN_ON(ret);
2742
2743         if (i_size_read(inode) > 0) {
2744                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2745                                                       inode);
2746                 if (ret)
2747                         goto out_put;
2748         }
2749
2750         spin_lock(&block_group->lock);
2751         if (block_group->cached != BTRFS_CACHE_FINISHED) {
2752                 spin_unlock(&block_group->lock);
2753                 goto out_put;
2754         }
2755         spin_unlock(&block_group->lock);
2756
2757         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2758         if (!num_pages)
2759                 num_pages = 1;
2760
2761         /*
2762          * Just to make absolutely sure we have enough space, we're going to
2763          * preallocate 12 pages worth of space for each block group.  In
2764          * practice we ought to use at most 8, but we need extra space so we can
2765          * add our header and have a terminator between the extents and the
2766          * bitmaps.
2767          */
2768         num_pages *= 16;
2769         num_pages *= PAGE_CACHE_SIZE;
2770
2771         ret = btrfs_check_data_free_space(inode, num_pages);
2772         if (ret)
2773                 goto out_put;
2774
2775         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2776                                               num_pages, num_pages,
2777                                               &alloc_hint);
2778         btrfs_free_reserved_data_space(inode, num_pages);
2779 out_put:
2780         iput(inode);
2781 out_free:
2782         btrfs_release_path(root, path);
2783 out:
2784         spin_lock(&block_group->lock);
2785         if (ret)
2786                 block_group->disk_cache_state = BTRFS_DC_ERROR;
2787         else
2788                 block_group->disk_cache_state = BTRFS_DC_SETUP;
2789         spin_unlock(&block_group->lock);
2790
2791         return ret;
2792 }
2793
2794 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2795                                    struct btrfs_root *root)
2796 {
2797         struct btrfs_block_group_cache *cache;
2798         int err = 0;
2799         struct btrfs_path *path;
2800         u64 last = 0;
2801
2802         path = btrfs_alloc_path();
2803         if (!path)
2804                 return -ENOMEM;
2805
2806 again:
2807         while (1) {
2808                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2809                 while (cache) {
2810                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2811                                 break;
2812                         cache = next_block_group(root, cache);
2813                 }
2814                 if (!cache) {
2815                         if (last == 0)
2816                                 break;
2817                         last = 0;
2818                         continue;
2819                 }
2820                 err = cache_save_setup(cache, trans, path);
2821                 last = cache->key.objectid + cache->key.offset;
2822                 btrfs_put_block_group(cache);
2823         }
2824
2825         while (1) {
2826                 if (last == 0) {
2827                         err = btrfs_run_delayed_refs(trans, root,
2828                                                      (unsigned long)-1);
2829                         BUG_ON(err);
2830                 }
2831
2832                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2833                 while (cache) {
2834                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
2835                                 btrfs_put_block_group(cache);
2836                                 goto again;
2837                         }
2838
2839                         if (cache->dirty)
2840                                 break;
2841                         cache = next_block_group(root, cache);
2842                 }
2843                 if (!cache) {
2844                         if (last == 0)
2845                                 break;
2846                         last = 0;
2847                         continue;
2848                 }
2849
2850                 cache->dirty = 0;
2851                 last = cache->key.objectid + cache->key.offset;
2852
2853                 err = write_one_cache_group(trans, root, path, cache);
2854                 BUG_ON(err);
2855                 btrfs_put_block_group(cache);
2856         }
2857
2858         btrfs_free_path(path);
2859         return 0;
2860 }
2861
2862 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
2863 {
2864         struct btrfs_block_group_cache *block_group;
2865         int readonly = 0;
2866
2867         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
2868         if (!block_group || block_group->ro)
2869                 readonly = 1;
2870         if (block_group)
2871                 btrfs_put_block_group(block_group);
2872         return readonly;
2873 }
2874
2875 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
2876                              u64 total_bytes, u64 bytes_used,
2877                              struct btrfs_space_info **space_info)
2878 {
2879         struct btrfs_space_info *found;
2880         int i;
2881         int factor;
2882
2883         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
2884                      BTRFS_BLOCK_GROUP_RAID10))
2885                 factor = 2;
2886         else
2887                 factor = 1;
2888
2889         found = __find_space_info(info, flags);
2890         if (found) {
2891                 spin_lock(&found->lock);
2892                 found->total_bytes += total_bytes;
2893                 found->bytes_used += bytes_used;
2894                 found->disk_used += bytes_used * factor;
2895                 found->full = 0;
2896                 spin_unlock(&found->lock);
2897                 *space_info = found;
2898                 return 0;
2899         }
2900         found = kzalloc(sizeof(*found), GFP_NOFS);
2901         if (!found)
2902                 return -ENOMEM;
2903
2904         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
2905                 INIT_LIST_HEAD(&found->block_groups[i]);
2906         init_rwsem(&found->groups_sem);
2907         spin_lock_init(&found->lock);
2908         found->flags = flags & (BTRFS_BLOCK_GROUP_DATA |
2909                                 BTRFS_BLOCK_GROUP_SYSTEM |
2910                                 BTRFS_BLOCK_GROUP_METADATA);
2911         found->total_bytes = total_bytes;
2912         found->bytes_used = bytes_used;
2913         found->disk_used = bytes_used * factor;
2914         found->bytes_pinned = 0;
2915         found->bytes_reserved = 0;
2916         found->bytes_readonly = 0;
2917         found->bytes_may_use = 0;
2918         found->full = 0;
2919         found->force_alloc = 0;
2920         *space_info = found;
2921         list_add_rcu(&found->list, &info->space_info);
2922         atomic_set(&found->caching_threads, 0);
2923         return 0;
2924 }
2925
2926 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
2927 {
2928         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
2929                                    BTRFS_BLOCK_GROUP_RAID1 |
2930                                    BTRFS_BLOCK_GROUP_RAID10 |
2931                                    BTRFS_BLOCK_GROUP_DUP);
2932         if (extra_flags) {
2933                 if (flags & BTRFS_BLOCK_GROUP_DATA)
2934                         fs_info->avail_data_alloc_bits |= extra_flags;
2935                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
2936                         fs_info->avail_metadata_alloc_bits |= extra_flags;
2937                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2938                         fs_info->avail_system_alloc_bits |= extra_flags;
2939         }
2940 }
2941
2942 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
2943 {
2944         u64 num_devices = root->fs_info->fs_devices->rw_devices;
2945
2946         if (num_devices == 1)
2947                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
2948         if (num_devices < 4)
2949                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
2950
2951         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
2952             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
2953                       BTRFS_BLOCK_GROUP_RAID10))) {
2954                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
2955         }
2956
2957         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
2958             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
2959                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
2960         }
2961
2962         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
2963             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
2964              (flags & BTRFS_BLOCK_GROUP_RAID10) |
2965              (flags & BTRFS_BLOCK_GROUP_DUP)))
2966                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
2967         return flags;
2968 }
2969
2970 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
2971 {
2972         if (flags & BTRFS_BLOCK_GROUP_DATA)
2973                 flags |= root->fs_info->avail_data_alloc_bits &
2974                          root->fs_info->data_alloc_profile;
2975         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2976                 flags |= root->fs_info->avail_system_alloc_bits &
2977                          root->fs_info->system_alloc_profile;
2978         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
2979                 flags |= root->fs_info->avail_metadata_alloc_bits &
2980                          root->fs_info->metadata_alloc_profile;
2981         return btrfs_reduce_alloc_profile(root, flags);
2982 }
2983
2984 static u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
2985 {
2986         u64 flags;
2987
2988         if (data)
2989                 flags = BTRFS_BLOCK_GROUP_DATA;
2990         else if (root == root->fs_info->chunk_root)
2991                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
2992         else
2993                 flags = BTRFS_BLOCK_GROUP_METADATA;
2994
2995         return get_alloc_profile(root, flags);
2996 }
2997
2998 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
2999 {
3000         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
3001                                                        BTRFS_BLOCK_GROUP_DATA);
3002 }
3003
3004 /*
3005  * This will check the space that the inode allocates from to make sure we have
3006  * enough space for bytes.
3007  */
3008 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3009 {
3010         struct btrfs_space_info *data_sinfo;
3011         struct btrfs_root *root = BTRFS_I(inode)->root;
3012         u64 used;
3013         int ret = 0, committed = 0, alloc_chunk = 1;
3014
3015         /* make sure bytes are sectorsize aligned */
3016         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3017
3018         if (root == root->fs_info->tree_root) {
3019                 alloc_chunk = 0;
3020                 committed = 1;
3021         }
3022
3023         data_sinfo = BTRFS_I(inode)->space_info;
3024         if (!data_sinfo)
3025                 goto alloc;
3026
3027 again:
3028         /* make sure we have enough space to handle the data first */
3029         spin_lock(&data_sinfo->lock);
3030         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3031                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3032                 data_sinfo->bytes_may_use;
3033
3034         if (used + bytes > data_sinfo->total_bytes) {
3035                 struct btrfs_trans_handle *trans;
3036
3037                 /*
3038                  * if we don't have enough free bytes in this space then we need
3039                  * to alloc a new chunk.
3040                  */
3041                 if (!data_sinfo->full && alloc_chunk) {
3042                         u64 alloc_target;
3043
3044                         data_sinfo->force_alloc = 1;
3045                         spin_unlock(&data_sinfo->lock);
3046 alloc:
3047                         alloc_target = btrfs_get_alloc_profile(root, 1);
3048                         trans = btrfs_join_transaction(root, 1);
3049                         if (IS_ERR(trans))
3050                                 return PTR_ERR(trans);
3051
3052                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3053                                              bytes + 2 * 1024 * 1024,
3054                                              alloc_target, 0);
3055                         btrfs_end_transaction(trans, root);
3056                         if (ret < 0)
3057                                 return ret;
3058
3059                         if (!data_sinfo) {
3060                                 btrfs_set_inode_space_info(root, inode);
3061                                 data_sinfo = BTRFS_I(inode)->space_info;
3062                         }
3063                         goto again;
3064                 }
3065                 spin_unlock(&data_sinfo->lock);
3066
3067                 /* commit the current transaction and try again */
3068                 if (!committed && !root->fs_info->open_ioctl_trans) {
3069                         committed = 1;
3070                         trans = btrfs_join_transaction(root, 1);
3071                         if (IS_ERR(trans))
3072                                 return PTR_ERR(trans);
3073                         ret = btrfs_commit_transaction(trans, root);
3074                         if (ret)
3075                                 return ret;
3076                         goto again;
3077                 }
3078
3079 #if 0 /* I hope we never need this code again, just in case */
3080                 printk(KERN_ERR "no space left, need %llu, %llu bytes_used, "
3081                        "%llu bytes_reserved, " "%llu bytes_pinned, "
3082                        "%llu bytes_readonly, %llu may use %llu total\n",
3083                        (unsigned long long)bytes,
3084                        (unsigned long long)data_sinfo->bytes_used,
3085                        (unsigned long long)data_sinfo->bytes_reserved,
3086                        (unsigned long long)data_sinfo->bytes_pinned,
3087                        (unsigned long long)data_sinfo->bytes_readonly,
3088                        (unsigned long long)data_sinfo->bytes_may_use,
3089                        (unsigned long long)data_sinfo->total_bytes);
3090 #endif
3091                 return -ENOSPC;
3092         }
3093         data_sinfo->bytes_may_use += bytes;
3094         BTRFS_I(inode)->reserved_bytes += bytes;
3095         spin_unlock(&data_sinfo->lock);
3096
3097         return 0;
3098 }
3099
3100 /*
3101  * called when we are clearing an delalloc extent from the
3102  * inode's io_tree or there was an error for whatever reason
3103  * after calling btrfs_check_data_free_space
3104  */
3105 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3106 {
3107         struct btrfs_root *root = BTRFS_I(inode)->root;
3108         struct btrfs_space_info *data_sinfo;
3109
3110         /* make sure bytes are sectorsize aligned */
3111         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3112
3113         data_sinfo = BTRFS_I(inode)->space_info;
3114         spin_lock(&data_sinfo->lock);
3115         data_sinfo->bytes_may_use -= bytes;
3116         BTRFS_I(inode)->reserved_bytes -= bytes;
3117         spin_unlock(&data_sinfo->lock);
3118 }
3119
3120 static void force_metadata_allocation(struct btrfs_fs_info *info)
3121 {
3122         struct list_head *head = &info->space_info;
3123         struct btrfs_space_info *found;
3124
3125         rcu_read_lock();
3126         list_for_each_entry_rcu(found, head, list) {
3127                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3128                         found->force_alloc = 1;
3129         }
3130         rcu_read_unlock();
3131 }
3132
3133 static int should_alloc_chunk(struct btrfs_space_info *sinfo,
3134                               u64 alloc_bytes)
3135 {
3136         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3137
3138         if (sinfo->bytes_used + sinfo->bytes_reserved +
3139             alloc_bytes + 256 * 1024 * 1024 < num_bytes)
3140                 return 0;
3141
3142         if (sinfo->bytes_used + sinfo->bytes_reserved +
3143             alloc_bytes < div_factor(num_bytes, 8))
3144                 return 0;
3145
3146         return 1;
3147 }
3148
3149 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3150                           struct btrfs_root *extent_root, u64 alloc_bytes,
3151                           u64 flags, int force)
3152 {
3153         struct btrfs_space_info *space_info;
3154         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3155         int ret = 0;
3156
3157         mutex_lock(&fs_info->chunk_mutex);
3158
3159         flags = btrfs_reduce_alloc_profile(extent_root, flags);
3160
3161         space_info = __find_space_info(extent_root->fs_info, flags);
3162         if (!space_info) {
3163                 ret = update_space_info(extent_root->fs_info, flags,
3164                                         0, 0, &space_info);
3165                 BUG_ON(ret);
3166         }
3167         BUG_ON(!space_info);
3168
3169         spin_lock(&space_info->lock);
3170         if (space_info->force_alloc)
3171                 force = 1;
3172         if (space_info->full) {
3173                 spin_unlock(&space_info->lock);
3174                 goto out;
3175         }
3176
3177         if (!force && !should_alloc_chunk(space_info, alloc_bytes)) {
3178                 spin_unlock(&space_info->lock);
3179                 goto out;
3180         }
3181         spin_unlock(&space_info->lock);
3182
3183         /*
3184          * if we're doing a data chunk, go ahead and make sure that
3185          * we keep a reasonable number of metadata chunks allocated in the
3186          * FS as well.
3187          */
3188         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3189                 fs_info->data_chunk_allocations++;
3190                 if (!(fs_info->data_chunk_allocations %
3191                       fs_info->metadata_ratio))
3192                         force_metadata_allocation(fs_info);
3193         }
3194
3195         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3196         spin_lock(&space_info->lock);
3197         if (ret)
3198                 space_info->full = 1;
3199         else
3200                 ret = 1;
3201         space_info->force_alloc = 0;
3202         spin_unlock(&space_info->lock);
3203 out:
3204         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3205         return ret;
3206 }
3207
3208 static int maybe_allocate_chunk(struct btrfs_trans_handle *trans,
3209                                 struct btrfs_root *root,
3210                                 struct btrfs_space_info *sinfo, u64 num_bytes)
3211 {
3212         int ret;
3213         int end_trans = 0;
3214
3215         if (sinfo->full)
3216                 return 0;
3217
3218         spin_lock(&sinfo->lock);
3219         ret = should_alloc_chunk(sinfo, num_bytes + 2 * 1024 * 1024);
3220         spin_unlock(&sinfo->lock);
3221         if (!ret)
3222                 return 0;
3223
3224         if (!trans) {
3225                 trans = btrfs_join_transaction(root, 1);
3226                 BUG_ON(IS_ERR(trans));
3227                 end_trans = 1;
3228         }
3229
3230         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3231                              num_bytes + 2 * 1024 * 1024,
3232                              get_alloc_profile(root, sinfo->flags), 0);
3233
3234         if (end_trans)
3235                 btrfs_end_transaction(trans, root);
3236
3237         return ret == 1 ? 1 : 0;
3238 }
3239
3240 /*
3241  * shrink metadata reservation for delalloc
3242  */
3243 static int shrink_delalloc(struct btrfs_trans_handle *trans,
3244                            struct btrfs_root *root, u64 to_reclaim)
3245 {
3246         struct btrfs_block_rsv *block_rsv;
3247         u64 reserved;
3248         u64 max_reclaim;
3249         u64 reclaimed = 0;
3250         int pause = 1;
3251         int ret;
3252
3253         block_rsv = &root->fs_info->delalloc_block_rsv;
3254         spin_lock(&block_rsv->lock);
3255         reserved = block_rsv->reserved;
3256         spin_unlock(&block_rsv->lock);
3257
3258         if (reserved == 0)
3259                 return 0;
3260
3261         max_reclaim = min(reserved, to_reclaim);
3262
3263         while (1) {
3264                 ret = btrfs_start_one_delalloc_inode(root, trans ? 1 : 0);
3265                 if (!ret) {
3266                         __set_current_state(TASK_INTERRUPTIBLE);
3267                         schedule_timeout(pause);
3268                         pause <<= 1;
3269                         if (pause > HZ / 10)
3270                                 pause = HZ / 10;
3271                 } else {
3272                         pause = 1;
3273                 }
3274
3275                 spin_lock(&block_rsv->lock);
3276                 if (reserved > block_rsv->reserved)
3277                         reclaimed = reserved - block_rsv->reserved;
3278                 reserved = block_rsv->reserved;
3279                 spin_unlock(&block_rsv->lock);
3280
3281                 if (reserved == 0 || reclaimed >= max_reclaim)
3282                         break;
3283
3284                 if (trans && trans->transaction->blocked)
3285                         return -EAGAIN;
3286         }
3287         return reclaimed >= to_reclaim;
3288 }
3289
3290 static int should_retry_reserve(struct btrfs_trans_handle *trans,
3291                                 struct btrfs_root *root,
3292                                 struct btrfs_block_rsv *block_rsv,
3293                                 u64 num_bytes, int *retries)
3294 {
3295         struct btrfs_space_info *space_info = block_rsv->space_info;
3296         int ret;
3297
3298         if ((*retries) > 2)
3299                 return -ENOSPC;
3300
3301         ret = maybe_allocate_chunk(trans, root, space_info, num_bytes);
3302         if (ret)
3303                 return 1;
3304
3305         if (trans && trans->transaction->in_commit)
3306                 return -ENOSPC;
3307
3308         ret = shrink_delalloc(trans, root, num_bytes);
3309         if (ret)
3310                 return ret;
3311
3312         spin_lock(&space_info->lock);
3313         if (space_info->bytes_pinned < num_bytes)
3314                 ret = 1;
3315         spin_unlock(&space_info->lock);
3316         if (ret)
3317                 return -ENOSPC;
3318
3319         (*retries)++;
3320
3321         if (trans)
3322                 return -EAGAIN;
3323
3324         trans = btrfs_join_transaction(root, 1);
3325         BUG_ON(IS_ERR(trans));
3326         ret = btrfs_commit_transaction(trans, root);
3327         BUG_ON(ret);
3328
3329         return 1;
3330 }
3331
3332 static int reserve_metadata_bytes(struct btrfs_block_rsv *block_rsv,
3333                                   u64 num_bytes)
3334 {
3335         struct btrfs_space_info *space_info = block_rsv->space_info;
3336         u64 unused;
3337         int ret = -ENOSPC;
3338
3339         spin_lock(&space_info->lock);
3340         unused = space_info->bytes_used + space_info->bytes_reserved +
3341                  space_info->bytes_pinned + space_info->bytes_readonly;
3342
3343         if (unused < space_info->total_bytes)
3344                 unused = space_info->total_bytes - unused;
3345         else
3346                 unused = 0;
3347
3348         if (unused >= num_bytes) {
3349                 if (block_rsv->priority >= 10) {
3350                         space_info->bytes_reserved += num_bytes;
3351                         ret = 0;
3352                 } else {
3353                         if ((unused + block_rsv->reserved) *
3354                             block_rsv->priority >=
3355                             (num_bytes + block_rsv->reserved) * 10) {
3356                                 space_info->bytes_reserved += num_bytes;
3357                                 ret = 0;
3358                         }
3359                 }
3360         }
3361         spin_unlock(&space_info->lock);
3362
3363         return ret;
3364 }
3365
3366 static struct btrfs_block_rsv *get_block_rsv(struct btrfs_trans_handle *trans,
3367                                              struct btrfs_root *root)
3368 {
3369         struct btrfs_block_rsv *block_rsv;
3370         if (root->ref_cows)
3371                 block_rsv = trans->block_rsv;
3372         else
3373                 block_rsv = root->block_rsv;
3374
3375         if (!block_rsv)
3376                 block_rsv = &root->fs_info->empty_block_rsv;
3377
3378         return block_rsv;
3379 }
3380
3381 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
3382                                u64 num_bytes)
3383 {
3384         int ret = -ENOSPC;
3385         spin_lock(&block_rsv->lock);
3386         if (block_rsv->reserved >= num_bytes) {
3387                 block_rsv->reserved -= num_bytes;
3388                 if (block_rsv->reserved < block_rsv->size)
3389                         block_rsv->full = 0;
3390                 ret = 0;
3391         }
3392         spin_unlock(&block_rsv->lock);
3393         return ret;
3394 }
3395
3396 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
3397                                 u64 num_bytes, int update_size)
3398 {
3399         spin_lock(&block_rsv->lock);
3400         block_rsv->reserved += num_bytes;
3401         if (update_size)
3402                 block_rsv->size += num_bytes;
3403         else if (block_rsv->reserved >= block_rsv->size)
3404                 block_rsv->full = 1;
3405         spin_unlock(&block_rsv->lock);
3406 }
3407
3408 void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv,
3409                              struct btrfs_block_rsv *dest, u64 num_bytes)
3410 {
3411         struct btrfs_space_info *space_info = block_rsv->space_info;
3412
3413         spin_lock(&block_rsv->lock);
3414         if (num_bytes == (u64)-1)
3415                 num_bytes = block_rsv->size;
3416         block_rsv->size -= num_bytes;
3417         if (block_rsv->reserved >= block_rsv->size) {
3418                 num_bytes = block_rsv->reserved - block_rsv->size;
3419                 block_rsv->reserved = block_rsv->size;
3420                 block_rsv->full = 1;
3421         } else {
3422                 num_bytes = 0;
3423         }
3424         spin_unlock(&block_rsv->lock);
3425
3426         if (num_bytes > 0) {
3427                 if (dest) {
3428                         block_rsv_add_bytes(dest, num_bytes, 0);
3429                 } else {
3430                         spin_lock(&space_info->lock);
3431                         space_info->bytes_reserved -= num_bytes;
3432                         spin_unlock(&space_info->lock);
3433                 }
3434         }
3435 }
3436
3437 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
3438                                    struct btrfs_block_rsv *dst, u64 num_bytes)
3439 {
3440         int ret;
3441
3442         ret = block_rsv_use_bytes(src, num_bytes);
3443         if (ret)
3444                 return ret;
3445
3446         block_rsv_add_bytes(dst, num_bytes, 1);
3447         return 0;
3448 }
3449
3450 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
3451 {
3452         memset(rsv, 0, sizeof(*rsv));
3453         spin_lock_init(&rsv->lock);
3454         atomic_set(&rsv->usage, 1);
3455         rsv->priority = 6;
3456         INIT_LIST_HEAD(&rsv->list);
3457 }
3458
3459 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
3460 {
3461         struct btrfs_block_rsv *block_rsv;
3462         struct btrfs_fs_info *fs_info = root->fs_info;
3463         u64 alloc_target;
3464
3465         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
3466         if (!block_rsv)
3467                 return NULL;
3468
3469         btrfs_init_block_rsv(block_rsv);
3470
3471         alloc_target = btrfs_get_alloc_profile(root, 0);
3472         block_rsv->space_info = __find_space_info(fs_info,
3473                                                   BTRFS_BLOCK_GROUP_METADATA);
3474
3475         return block_rsv;
3476 }
3477
3478 void btrfs_free_block_rsv(struct btrfs_root *root,
3479                           struct btrfs_block_rsv *rsv)
3480 {
3481         if (rsv && atomic_dec_and_test(&rsv->usage)) {
3482                 btrfs_block_rsv_release(root, rsv, (u64)-1);
3483                 if (!rsv->durable)
3484                         kfree(rsv);
3485         }
3486 }
3487
3488 /*
3489  * make the block_rsv struct be able to capture freed space.
3490  * the captured space will re-add to the the block_rsv struct
3491  * after transaction commit
3492  */
3493 void btrfs_add_durable_block_rsv(struct btrfs_fs_info *fs_info,
3494                                  struct btrfs_block_rsv *block_rsv)
3495 {
3496         block_rsv->durable = 1;
3497         mutex_lock(&fs_info->durable_block_rsv_mutex);
3498         list_add_tail(&block_rsv->list, &fs_info->durable_block_rsv_list);
3499         mutex_unlock(&fs_info->durable_block_rsv_mutex);
3500 }
3501
3502 int btrfs_block_rsv_add(struct btrfs_trans_handle *trans,
3503                         struct btrfs_root *root,
3504                         struct btrfs_block_rsv *block_rsv,
3505                         u64 num_bytes, int *retries)
3506 {
3507         int ret;
3508
3509         if (num_bytes == 0)
3510                 return 0;
3511 again:
3512         ret = reserve_metadata_bytes(block_rsv, num_bytes);
3513         if (!ret) {
3514                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
3515                 return 0;
3516         }
3517
3518         ret = should_retry_reserve(trans, root, block_rsv, num_bytes, retries);
3519         if (ret > 0)
3520                 goto again;
3521
3522         return ret;
3523 }
3524
3525 int btrfs_block_rsv_check(struct btrfs_trans_handle *trans,
3526                           struct btrfs_root *root,
3527                           struct btrfs_block_rsv *block_rsv,
3528                           u64 min_reserved, int min_factor)
3529 {
3530         u64 num_bytes = 0;
3531         int commit_trans = 0;
3532         int ret = -ENOSPC;
3533
3534         if (!block_rsv)
3535                 return 0;
3536
3537         spin_lock(&block_rsv->lock);
3538         if (min_factor > 0)
3539                 num_bytes = div_factor(block_rsv->size, min_factor);
3540         if (min_reserved > num_bytes)
3541                 num_bytes = min_reserved;
3542
3543         if (block_rsv->reserved >= num_bytes) {
3544                 ret = 0;
3545         } else {
3546                 num_bytes -= block_rsv->reserved;
3547                 if (block_rsv->durable &&
3548                     block_rsv->freed[0] + block_rsv->freed[1] >= num_bytes)
3549                         commit_trans = 1;
3550         }
3551         spin_unlock(&block_rsv->lock);
3552         if (!ret)
3553                 return 0;
3554
3555         if (block_rsv->refill_used) {
3556                 ret = reserve_metadata_bytes(block_rsv, num_bytes);
3557                 if (!ret) {
3558                         block_rsv_add_bytes(block_rsv, num_bytes, 0);
3559                         return 0;
3560                 }
3561         }
3562
3563         if (commit_trans) {
3564                 if (trans)
3565                         return -EAGAIN;
3566
3567                 trans = btrfs_join_transaction(root, 1);
3568                 BUG_ON(IS_ERR(trans));
3569                 ret = btrfs_commit_transaction(trans, root);
3570                 return 0;
3571         }
3572
3573         WARN_ON(1);
3574         printk(KERN_INFO"block_rsv size %llu reserved %llu freed %llu %llu\n",
3575                 block_rsv->size, block_rsv->reserved,
3576                 block_rsv->freed[0], block_rsv->freed[1]);
3577
3578         return -ENOSPC;
3579 }
3580
3581 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
3582                             struct btrfs_block_rsv *dst_rsv,
3583                             u64 num_bytes)
3584 {
3585         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3586 }
3587
3588 void btrfs_block_rsv_release(struct btrfs_root *root,
3589                              struct btrfs_block_rsv *block_rsv,
3590                              u64 num_bytes)
3591 {
3592         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3593         if (global_rsv->full || global_rsv == block_rsv ||
3594             block_rsv->space_info != global_rsv->space_info)
3595                 global_rsv = NULL;
3596         block_rsv_release_bytes(block_rsv, global_rsv, num_bytes);
3597 }
3598
3599 /*
3600  * helper to calculate size of global block reservation.
3601  * the desired value is sum of space used by extent tree,
3602  * checksum tree and root tree
3603  */
3604 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
3605 {
3606         struct btrfs_space_info *sinfo;
3607         u64 num_bytes;
3608         u64 meta_used;
3609         u64 data_used;
3610         int csum_size = btrfs_super_csum_size(&fs_info->super_copy);
3611 #if 0
3612         /*
3613          * per tree used space accounting can be inaccuracy, so we
3614          * can't rely on it.
3615          */
3616         spin_lock(&fs_info->extent_root->accounting_lock);
3617         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item);
3618         spin_unlock(&fs_info->extent_root->accounting_lock);
3619
3620         spin_lock(&fs_info->csum_root->accounting_lock);
3621         num_bytes += btrfs_root_used(&fs_info->csum_root->root_item);
3622         spin_unlock(&fs_info->csum_root->accounting_lock);
3623
3624         spin_lock(&fs_info->tree_root->accounting_lock);
3625         num_bytes += btrfs_root_used(&fs_info->tree_root->root_item);
3626         spin_unlock(&fs_info->tree_root->accounting_lock);
3627 #endif
3628         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
3629         spin_lock(&sinfo->lock);
3630         data_used = sinfo->bytes_used;
3631         spin_unlock(&sinfo->lock);
3632
3633         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3634         spin_lock(&sinfo->lock);
3635         meta_used = sinfo->bytes_used;
3636         spin_unlock(&sinfo->lock);
3637
3638         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
3639                     csum_size * 2;
3640         num_bytes += div64_u64(data_used + meta_used, 50);
3641
3642         if (num_bytes * 3 > meta_used)
3643                 num_bytes = div64_u64(meta_used, 3);
3644
3645         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
3646 }
3647
3648 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
3649 {
3650         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
3651         struct btrfs_space_info *sinfo = block_rsv->space_info;
3652         u64 num_bytes;
3653
3654         num_bytes = calc_global_metadata_size(fs_info);
3655
3656         spin_lock(&block_rsv->lock);
3657         spin_lock(&sinfo->lock);
3658
3659         block_rsv->size = num_bytes;
3660
3661         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
3662                     sinfo->bytes_reserved + sinfo->bytes_readonly;
3663
3664         if (sinfo->total_bytes > num_bytes) {
3665                 num_bytes = sinfo->total_bytes - num_bytes;
3666                 block_rsv->reserved += num_bytes;
3667                 sinfo->bytes_reserved += num_bytes;
3668         }
3669
3670         if (block_rsv->reserved >= block_rsv->size) {
3671                 num_bytes = block_rsv->reserved - block_rsv->size;
3672                 sinfo->bytes_reserved -= num_bytes;
3673                 block_rsv->reserved = block_rsv->size;
3674                 block_rsv->full = 1;
3675         }
3676 #if 0
3677         printk(KERN_INFO"global block rsv size %llu reserved %llu\n",
3678                 block_rsv->size, block_rsv->reserved);
3679 #endif
3680         spin_unlock(&sinfo->lock);
3681         spin_unlock(&block_rsv->lock);
3682 }
3683
3684 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
3685 {
3686         struct btrfs_space_info *space_info;
3687
3688         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3689         fs_info->chunk_block_rsv.space_info = space_info;
3690         fs_info->chunk_block_rsv.priority = 10;
3691
3692         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3693         fs_info->global_block_rsv.space_info = space_info;
3694         fs_info->global_block_rsv.priority = 10;
3695         fs_info->global_block_rsv.refill_used = 1;
3696         fs_info->delalloc_block_rsv.space_info = space_info;
3697         fs_info->trans_block_rsv.space_info = space_info;
3698         fs_info->empty_block_rsv.space_info = space_info;
3699         fs_info->empty_block_rsv.priority = 10;
3700
3701         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
3702         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
3703         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
3704         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
3705         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
3706
3707         btrfs_add_durable_block_rsv(fs_info, &fs_info->global_block_rsv);
3708
3709         btrfs_add_durable_block_rsv(fs_info, &fs_info->delalloc_block_rsv);
3710
3711         update_global_block_rsv(fs_info);
3712 }
3713
3714 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
3715 {
3716         block_rsv_release_bytes(&fs_info->global_block_rsv, NULL, (u64)-1);
3717         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
3718         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
3719         WARN_ON(fs_info->trans_block_rsv.size > 0);
3720         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
3721         WARN_ON(fs_info->chunk_block_rsv.size > 0);
3722         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
3723 }
3724
3725 static u64 calc_trans_metadata_size(struct btrfs_root *root, int num_items)
3726 {
3727         return (root->leafsize + root->nodesize * (BTRFS_MAX_LEVEL - 1)) *
3728                 3 * num_items;
3729 }
3730
3731 int btrfs_trans_reserve_metadata(struct btrfs_trans_handle *trans,
3732                                  struct btrfs_root *root,
3733                                  int num_items, int *retries)
3734 {
3735         u64 num_bytes;
3736         int ret;
3737
3738         if (num_items == 0 || root->fs_info->chunk_root == root)
3739                 return 0;
3740
3741         num_bytes = calc_trans_metadata_size(root, num_items);
3742         ret = btrfs_block_rsv_add(trans, root, &root->fs_info->trans_block_rsv,
3743                                   num_bytes, retries);
3744         if (!ret) {
3745                 trans->bytes_reserved += num_bytes;
3746                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3747         }
3748         return ret;
3749 }
3750
3751 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
3752                                   struct btrfs_root *root)
3753 {
3754         if (!trans->bytes_reserved)
3755                 return;
3756
3757         BUG_ON(trans->block_rsv != &root->fs_info->trans_block_rsv);
3758         btrfs_block_rsv_release(root, trans->block_rsv,
3759                                 trans->bytes_reserved);
3760         trans->bytes_reserved = 0;
3761 }
3762
3763 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
3764                                   struct inode *inode)
3765 {
3766         struct btrfs_root *root = BTRFS_I(inode)->root;
3767         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
3768         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
3769
3770         /*
3771          * one for deleting orphan item, one for updating inode and
3772          * two for calling btrfs_truncate_inode_items.
3773          *
3774          * btrfs_truncate_inode_items is a delete operation, it frees
3775          * more space than it uses in most cases. So two units of
3776          * metadata space should be enough for calling it many times.
3777          * If all of the metadata space is used, we can commit
3778          * transaction and use space it freed.
3779          */
3780         u64 num_bytes = calc_trans_metadata_size(root, 4);
3781         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3782 }
3783
3784 void btrfs_orphan_release_metadata(struct inode *inode)
3785 {
3786         struct btrfs_root *root = BTRFS_I(inode)->root;
3787         u64 num_bytes = calc_trans_metadata_size(root, 4);
3788         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
3789 }
3790
3791 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
3792                                 struct btrfs_pending_snapshot *pending)
3793 {
3794         struct btrfs_root *root = pending->root;
3795         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
3796         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
3797         /*
3798          * two for root back/forward refs, two for directory entries
3799          * and one for root of the snapshot.
3800          */
3801         u64 num_bytes = calc_trans_metadata_size(root, 5);
3802         dst_rsv->space_info = src_rsv->space_info;
3803         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3804 }
3805
3806 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes)
3807 {
3808         return num_bytes >>= 3;
3809 }
3810
3811 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
3812 {
3813         struct btrfs_root *root = BTRFS_I(inode)->root;
3814         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
3815         u64 to_reserve;
3816         int nr_extents;
3817         int retries = 0;
3818         int ret;
3819
3820         if (btrfs_transaction_in_commit(root->fs_info))
3821                 schedule_timeout(1);
3822
3823         num_bytes = ALIGN(num_bytes, root->sectorsize);
3824 again:
3825         spin_lock(&BTRFS_I(inode)->accounting_lock);
3826         nr_extents = atomic_read(&BTRFS_I(inode)->outstanding_extents) + 1;
3827         if (nr_extents > BTRFS_I(inode)->reserved_extents) {
3828                 nr_extents -= BTRFS_I(inode)->reserved_extents;
3829                 to_reserve = calc_trans_metadata_size(root, nr_extents);
3830         } else {
3831                 nr_extents = 0;
3832                 to_reserve = 0;
3833         }
3834
3835         to_reserve += calc_csum_metadata_size(inode, num_bytes);
3836         ret = reserve_metadata_bytes(block_rsv, to_reserve);
3837         if (ret) {
3838                 spin_unlock(&BTRFS_I(inode)->accounting_lock);
3839                 ret = should_retry_reserve(NULL, root, block_rsv, to_reserve,
3840                                            &retries);
3841                 if (ret > 0)
3842                         goto again;
3843                 return ret;
3844         }
3845
3846         BTRFS_I(inode)->reserved_extents += nr_extents;
3847         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
3848         spin_unlock(&BTRFS_I(inode)->accounting_lock);
3849
3850         block_rsv_add_bytes(block_rsv, to_reserve, 1);
3851
3852         if (block_rsv->size > 512 * 1024 * 1024)
3853                 shrink_delalloc(NULL, root, to_reserve);
3854
3855         return 0;
3856 }
3857
3858 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
3859 {
3860         struct btrfs_root *root = BTRFS_I(inode)->root;
3861         u64 to_free;
3862         int nr_extents;
3863
3864         num_bytes = ALIGN(num_bytes, root->sectorsize);
3865         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
3866
3867         spin_lock(&BTRFS_I(inode)->accounting_lock);
3868         nr_extents = atomic_read(&BTRFS_I(inode)->outstanding_extents);
3869         if (nr_extents < BTRFS_I(inode)->reserved_extents) {
3870                 nr_extents = BTRFS_I(inode)->reserved_extents - nr_extents;
3871                 BTRFS_I(inode)->reserved_extents -= nr_extents;
3872         } else {
3873                 nr_extents = 0;
3874         }
3875         spin_unlock(&BTRFS_I(inode)->accounting_lock);
3876
3877         to_free = calc_csum_metadata_size(inode, num_bytes);
3878         if (nr_extents > 0)
3879                 to_free += calc_trans_metadata_size(root, nr_extents);
3880
3881         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
3882                                 to_free);
3883 }
3884
3885 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
3886 {
3887         int ret;
3888
3889         ret = btrfs_check_data_free_space(inode, num_bytes);
3890         if (ret)
3891                 return ret;
3892
3893         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
3894         if (ret) {
3895                 btrfs_free_reserved_data_space(inode, num_bytes);
3896                 return ret;
3897         }
3898
3899         return 0;
3900 }
3901
3902 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
3903 {
3904         btrfs_delalloc_release_metadata(inode, num_bytes);
3905         btrfs_free_reserved_data_space(inode, num_bytes);
3906 }
3907
3908 static int update_block_group(struct btrfs_trans_handle *trans,
3909                               struct btrfs_root *root,
3910                               u64 bytenr, u64 num_bytes, int alloc)
3911 {
3912         struct btrfs_block_group_cache *cache = NULL;
3913         struct btrfs_fs_info *info = root->fs_info;
3914         u64 total = num_bytes;
3915         u64 old_val;
3916         u64 byte_in_group;
3917         int factor;
3918
3919         /* block accounting for super block */
3920         spin_lock(&info->delalloc_lock);
3921         old_val = btrfs_super_bytes_used(&info->super_copy);
3922         if (alloc)
3923                 old_val += num_bytes;
3924         else
3925                 old_val -= num_bytes;
3926         btrfs_set_super_bytes_used(&info->super_copy, old_val);
3927         spin_unlock(&info->delalloc_lock);
3928
3929         while (total) {
3930                 cache = btrfs_lookup_block_group(info, bytenr);
3931                 if (!cache)
3932                         return -1;
3933                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
3934                                     BTRFS_BLOCK_GROUP_RAID1 |
3935                                     BTRFS_BLOCK_GROUP_RAID10))
3936                         factor = 2;
3937                 else
3938                         factor = 1;
3939
3940                 byte_in_group = bytenr - cache->key.objectid;
3941                 WARN_ON(byte_in_group > cache->key.offset);
3942
3943                 spin_lock(&cache->space_info->lock);
3944                 spin_lock(&cache->lock);
3945
3946                 if (btrfs_super_cache_generation(&info->super_copy) != 0 &&
3947                     cache->disk_cache_state < BTRFS_DC_CLEAR)
3948                         cache->disk_cache_state = BTRFS_DC_CLEAR;
3949
3950                 cache->dirty = 1;
3951                 old_val = btrfs_block_group_used(&cache->item);
3952                 num_bytes = min(total, cache->key.offset - byte_in_group);
3953                 if (alloc) {
3954                         old_val += num_bytes;
3955                         btrfs_set_block_group_used(&cache->item, old_val);
3956                         cache->reserved -= num_bytes;
3957                         cache->space_info->bytes_reserved -= num_bytes;
3958                         cache->space_info->bytes_used += num_bytes;
3959                         cache->space_info->disk_used += num_bytes * factor;
3960                         spin_unlock(&cache->lock);
3961                         spin_unlock(&cache->space_info->lock);
3962                 } else {
3963                         old_val -= num_bytes;
3964                         btrfs_set_block_group_used(&cache->item, old_val);
3965                         cache->pinned += num_bytes;
3966                         cache->space_info->bytes_pinned += num_bytes;
3967                         cache->space_info->bytes_used -= num_bytes;
3968                         cache->space_info->disk_used -= num_bytes * factor;
3969                         spin_unlock(&cache->lock);
3970                         spin_unlock(&cache->space_info->lock);
3971
3972                         set_extent_dirty(info->pinned_extents,
3973                                          bytenr, bytenr + num_bytes - 1,
3974                                          GFP_NOFS | __GFP_NOFAIL);
3975                 }
3976                 btrfs_put_block_group(cache);
3977                 total -= num_bytes;
3978                 bytenr += num_bytes;
3979         }
3980         return 0;
3981 }
3982
3983 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
3984 {
3985         struct btrfs_block_group_cache *cache;
3986         u64 bytenr;
3987
3988         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
3989         if (!cache)
3990                 return 0;
3991
3992         bytenr = cache->key.objectid;
3993         btrfs_put_block_group(cache);
3994
3995         return bytenr;
3996 }
3997
3998 static int pin_down_extent(struct btrfs_root *root,
3999                            struct btrfs_block_group_cache *cache,
4000                            u64 bytenr, u64 num_bytes, int reserved)
4001 {
4002         spin_lock(&cache->space_info->lock);
4003         spin_lock(&cache->lock);
4004         cache->pinned += num_bytes;
4005         cache->space_info->bytes_pinned += num_bytes;
4006         if (reserved) {
4007                 cache->reserved -= num_bytes;
4008                 cache->space_info->bytes_reserved -= num_bytes;
4009         }
4010         spin_unlock(&cache->lock);
4011         spin_unlock(&cache->space_info->lock);
4012
4013         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4014                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4015         return 0;
4016 }
4017
4018 /*
4019  * this function must be called within transaction
4020  */
4021 int btrfs_pin_extent(struct btrfs_root *root,
4022                      u64 bytenr, u64 num_bytes, int reserved)
4023 {
4024         struct btrfs_block_group_cache *cache;
4025
4026         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4027         BUG_ON(!cache);
4028
4029         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4030
4031         btrfs_put_block_group(cache);
4032         return 0;
4033 }
4034
4035 /*
4036  * update size of reserved extents. this function may return -EAGAIN
4037  * if 'reserve' is true or 'sinfo' is false.
4038  */
4039 static int update_reserved_bytes(struct btrfs_block_group_cache *cache,
4040                                  u64 num_bytes, int reserve, int sinfo)
4041 {
4042         int ret = 0;
4043         if (sinfo) {
4044                 struct btrfs_space_info *space_info = cache->space_info;
4045                 spin_lock(&space_info->lock);
4046                 spin_lock(&cache->lock);
4047                 if (reserve) {
4048                         if (cache->ro) {
4049                                 ret = -EAGAIN;
4050                         } else {
4051                                 cache->reserved += num_bytes;
4052                                 space_info->bytes_reserved += num_bytes;
4053                         }
4054                 } else {
4055                         if (cache->ro)
4056                                 space_info->bytes_readonly += num_bytes;
4057                         cache->reserved -= num_bytes;
4058                         space_info->bytes_reserved -= num_bytes;
4059                 }
4060                 spin_unlock(&cache->lock);
4061                 spin_unlock(&space_info->lock);
4062         } else {
4063                 spin_lock(&cache->lock);
4064                 if (cache->ro) {
4065                         ret = -EAGAIN;
4066                 } else {
4067                         if (reserve)
4068                                 cache->reserved += num_bytes;
4069                         else
4070                                 cache->reserved -= num_bytes;
4071                 }
4072                 spin_unlock(&cache->lock);
4073         }
4074         return ret;
4075 }
4076
4077 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4078                                 struct btrfs_root *root)
4079 {
4080         struct btrfs_fs_info *fs_info = root->fs_info;
4081         struct btrfs_caching_control *next;
4082         struct btrfs_caching_control *caching_ctl;
4083         struct btrfs_block_group_cache *cache;
4084
4085         down_write(&fs_info->extent_commit_sem);
4086
4087         list_for_each_entry_safe(caching_ctl, next,
4088                                  &fs_info->caching_block_groups, list) {
4089                 cache = caching_ctl->block_group;
4090                 if (block_group_cache_done(cache)) {
4091                         cache->last_byte_to_unpin = (u64)-1;
4092                         list_del_init(&caching_ctl->list);
4093                         put_caching_control(caching_ctl);
4094                 } else {
4095                         cache->last_byte_to_unpin = caching_ctl->progress;
4096                 }
4097         }
4098
4099         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4100                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4101         else
4102                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4103
4104         up_write(&fs_info->extent_commit_sem);
4105
4106         update_global_block_rsv(fs_info);
4107         return 0;
4108 }
4109
4110 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4111 {
4112         struct btrfs_fs_info *fs_info = root->fs_info;
4113         struct btrfs_block_group_cache *cache = NULL;
4114         u64 len;
4115
4116         while (start <= end) {
4117                 if (!cache ||
4118                     start >= cache->key.objectid + cache->key.offset) {
4119                         if (cache)
4120                                 btrfs_put_block_group(cache);
4121                         cache = btrfs_lookup_block_group(fs_info, start);
4122                         BUG_ON(!cache);
4123                 }
4124
4125                 len = cache->key.objectid + cache->key.offset - start;
4126                 len = min(len, end + 1 - start);
4127
4128                 if (start < cache->last_byte_to_unpin) {
4129                         len = min(len, cache->last_byte_to_unpin - start);
4130                         btrfs_add_free_space(cache, start, len);
4131                 }
4132
4133                 start += len;
4134
4135                 spin_lock(&cache->space_info->lock);
4136                 spin_lock(&cache->lock);
4137                 cache->pinned -= len;
4138                 cache->space_info->bytes_pinned -= len;
4139                 if (cache->ro) {
4140                         cache->space_info->bytes_readonly += len;
4141                 } else if (cache->reserved_pinned > 0) {
4142                         len = min(len, cache->reserved_pinned);
4143                         cache->reserved_pinned -= len;
4144                         cache->space_info->bytes_reserved += len;
4145                 }
4146                 spin_unlock(&cache->lock);
4147                 spin_unlock(&cache->space_info->lock);
4148         }
4149
4150         if (cache)
4151                 btrfs_put_block_group(cache);
4152         return 0;
4153 }
4154
4155 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4156                                struct btrfs_root *root)
4157 {
4158         struct btrfs_fs_info *fs_info = root->fs_info;
4159         struct extent_io_tree *unpin;
4160         struct btrfs_block_rsv *block_rsv;
4161         struct btrfs_block_rsv *next_rsv;
4162         u64 start;
4163         u64 end;
4164         int idx;
4165         int ret;
4166
4167         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4168                 unpin = &fs_info->freed_extents[1];
4169         else
4170                 unpin = &fs_info->freed_extents[0];
4171
4172         while (1) {
4173                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4174                                             EXTENT_DIRTY);
4175                 if (ret)
4176                         break;
4177
4178                 ret = btrfs_discard_extent(root, start, end + 1 - start);
4179
4180                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4181                 unpin_extent_range(root, start, end);
4182                 cond_resched();
4183         }
4184
4185         mutex_lock(&fs_info->durable_block_rsv_mutex);
4186         list_for_each_entry_safe(block_rsv, next_rsv,
4187                                  &fs_info->durable_block_rsv_list, list) {
4188
4189                 idx = trans->transid & 0x1;
4190                 if (block_rsv->freed[idx] > 0) {
4191                         block_rsv_add_bytes(block_rsv,
4192                                             block_rsv->freed[idx], 0);
4193                         block_rsv->freed[idx] = 0;
4194                 }
4195                 if (atomic_read(&block_rsv->usage) == 0) {
4196                         btrfs_block_rsv_release(root, block_rsv, (u64)-1);
4197
4198                         if (block_rsv->freed[0] == 0 &&
4199                             block_rsv->freed[1] == 0) {
4200                                 list_del_init(&block_rsv->list);
4201                                 kfree(block_rsv);
4202                         }
4203                 } else {
4204                         btrfs_block_rsv_release(root, block_rsv, 0);
4205                 }
4206         }
4207         mutex_unlock(&fs_info->durable_block_rsv_mutex);
4208
4209         return 0;
4210 }
4211
4212 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
4213                                 struct btrfs_root *root,
4214                                 u64 bytenr, u64 num_bytes, u64 parent,
4215                                 u64 root_objectid, u64 owner_objectid,
4216                                 u64 owner_offset, int refs_to_drop,
4217                                 struct btrfs_delayed_extent_op *extent_op)
4218 {
4219         struct btrfs_key key;
4220         struct btrfs_path *path;
4221         struct btrfs_fs_info *info = root->fs_info;
4222         struct btrfs_root *extent_root = info->extent_root;
4223         struct extent_buffer *leaf;
4224         struct btrfs_extent_item *ei;
4225         struct btrfs_extent_inline_ref *iref;
4226         int ret;
4227         int is_data;
4228         int extent_slot = 0;
4229         int found_extent = 0;
4230         int num_to_del = 1;
4231         u32 item_size;
4232         u64 refs;
4233
4234         path = btrfs_alloc_path();
4235         if (!path)
4236                 return -ENOMEM;
4237
4238         path->reada = 1;
4239         path->leave_spinning = 1;
4240
4241         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
4242         BUG_ON(!is_data && refs_to_drop != 1);
4243
4244         ret = lookup_extent_backref(trans, extent_root, path, &iref,
4245                                     bytenr, num_bytes, parent,
4246                                     root_objectid, owner_objectid,
4247                                     owner_offset);
4248         if (ret == 0) {
4249                 extent_slot = path->slots[0];
4250                 while (extent_slot >= 0) {
4251                         btrfs_item_key_to_cpu(path->nodes[0], &key,
4252                                               extent_slot);
4253                         if (key.objectid != bytenr)
4254                                 break;
4255                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
4256                             key.offset == num_bytes) {
4257                                 found_extent = 1;
4258                                 break;
4259                         }
4260                         if (path->slots[0] - extent_slot > 5)
4261                                 break;
4262                         extent_slot--;
4263                 }
4264 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4265                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
4266                 if (found_extent && item_size < sizeof(*ei))
4267                         found_extent = 0;
4268 #endif
4269                 if (!found_extent) {
4270                         BUG_ON(iref);
4271                         ret = remove_extent_backref(trans, extent_root, path,
4272                                                     NULL, refs_to_drop,
4273                                                     is_data);
4274                         BUG_ON(ret);
4275                         btrfs_release_path(extent_root, path);
4276                         path->leave_spinning = 1;
4277
4278                         key.objectid = bytenr;
4279                         key.type = BTRFS_EXTENT_ITEM_KEY;
4280                         key.offset = num_bytes;
4281
4282                         ret = btrfs_search_slot(trans, extent_root,
4283                                                 &key, path, -1, 1);
4284                         if (ret) {
4285                                 printk(KERN_ERR "umm, got %d back from search"
4286                                        ", was looking for %llu\n", ret,
4287                                        (unsigned long long)bytenr);
4288                                 btrfs_print_leaf(extent_root, path->nodes[0]);
4289                         }
4290                         BUG_ON(ret);
4291                         extent_slot = path->slots[0];
4292                 }
4293         } else {
4294                 btrfs_print_leaf(extent_root, path->nodes[0]);
4295                 WARN_ON(1);
4296                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
4297                        "parent %llu root %llu  owner %llu offset %llu\n",
4298                        (unsigned long long)bytenr,
4299                        (unsigned long long)parent,
4300                        (unsigned long long)root_objectid,
4301                        (unsigned long long)owner_objectid,
4302                        (unsigned long long)owner_offset);
4303         }
4304
4305         leaf = path->nodes[0];
4306         item_size = btrfs_item_size_nr(leaf, extent_slot);
4307 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4308         if (item_size < sizeof(*ei)) {
4309                 BUG_ON(found_extent || extent_slot != path->slots[0]);
4310                 ret = convert_extent_item_v0(trans, extent_root, path,
4311                                              owner_objectid, 0);
4312                 BUG_ON(ret < 0);
4313
4314                 btrfs_release_path(extent_root, path);
4315                 path->leave_spinning = 1;
4316
4317                 key.objectid = bytenr;
4318                 key.type = BTRFS_EXTENT_ITEM_KEY;
4319                 key.offset = num_bytes;
4320
4321                 ret = btrfs_search_slot(trans, extent_root, &key, path,
4322                                         -1, 1);
4323                 if (ret) {
4324                         printk(KERN_ERR "umm, got %d back from search"
4325                                ", was looking for %llu\n", ret,
4326                                (unsigned long long)bytenr);
4327                         btrfs_print_leaf(extent_root, path->nodes[0]);
4328                 }
4329                 BUG_ON(ret);
4330                 extent_slot = path->slots[0];
4331                 leaf = path->nodes[0];
4332                 item_size = btrfs_item_size_nr(leaf, extent_slot);
4333         }
4334 #endif
4335         BUG_ON(item_size < sizeof(*ei));
4336         ei = btrfs_item_ptr(leaf, extent_slot,
4337                             struct btrfs_extent_item);
4338         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4339                 struct btrfs_tree_block_info *bi;
4340                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
4341                 bi = (struct btrfs_tree_block_info *)(ei + 1);
4342                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
4343         }
4344
4345         refs = btrfs_extent_refs(leaf, ei);
4346         BUG_ON(refs < refs_to_drop);
4347         refs -= refs_to_drop;
4348
4349         if (refs > 0) {
4350                 if (extent_op)
4351                         __run_delayed_extent_op(extent_op, leaf, ei);
4352                 /*
4353                  * In the case of inline back ref, reference count will
4354                  * be updated by remove_extent_backref
4355                  */
4356                 if (iref) {
4357                         BUG_ON(!found_extent);
4358                 } else {
4359                         btrfs_set_extent_refs(leaf, ei, refs);
4360                         btrfs_mark_buffer_dirty(leaf);
4361                 }
4362                 if (found_extent) {
4363                         ret = remove_extent_backref(trans, extent_root, path,
4364                                                     iref, refs_to_drop,
4365                                                     is_data);
4366                         BUG_ON(ret);
4367                 }
4368         } else {
4369                 if (found_extent) {
4370                         BUG_ON(is_data && refs_to_drop !=
4371                                extent_data_ref_count(root, path, iref));
4372                         if (iref) {
4373                                 BUG_ON(path->slots[0] != extent_slot);
4374                         } else {
4375                                 BUG_ON(path->slots[0] != extent_slot + 1);
4376                                 path->slots[0] = extent_slot;
4377                                 num_to_del = 2;
4378                         }
4379                 }
4380
4381                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
4382                                       num_to_del);
4383                 BUG_ON(ret);
4384                 btrfs_release_path(extent_root, path);
4385
4386                 if (is_data) {
4387                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
4388                         BUG_ON(ret);
4389                 } else {
4390                         invalidate_mapping_pages(info->btree_inode->i_mapping,
4391                              bytenr >> PAGE_CACHE_SHIFT,
4392                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
4393                 }
4394
4395                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
4396                 BUG_ON(ret);
4397         }
4398         btrfs_free_path(path);
4399         return ret;
4400 }
4401
4402 /*
4403  * when we free an block, it is possible (and likely) that we free the last
4404  * delayed ref for that extent as well.  This searches the delayed ref tree for
4405  * a given extent, and if there are no other delayed refs to be processed, it
4406  * removes it from the tree.
4407  */
4408 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
4409                                       struct btrfs_root *root, u64 bytenr)
4410 {
4411         struct btrfs_delayed_ref_head *head;
4412         struct btrfs_delayed_ref_root *delayed_refs;
4413         struct btrfs_delayed_ref_node *ref;
4414         struct rb_node *node;
4415         int ret = 0;
4416
4417         delayed_refs = &trans->transaction->delayed_refs;
4418         spin_lock(&delayed_refs->lock);
4419         head = btrfs_find_delayed_ref_head(trans, bytenr);
4420         if (!head)
4421                 goto out;
4422
4423         node = rb_prev(&head->node.rb_node);
4424         if (!node)
4425                 goto out;
4426
4427         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
4428
4429         /* there are still entries for this ref, we can't drop it */
4430         if (ref->bytenr == bytenr)
4431                 goto out;
4432
4433         if (head->extent_op) {
4434                 if (!head->must_insert_reserved)
4435                         goto out;
4436                 kfree(head->extent_op);
4437                 head->extent_op = NULL;
4438         }
4439
4440         /*
4441          * waiting for the lock here would deadlock.  If someone else has it
4442          * locked they are already in the process of dropping it anyway
4443          */
4444         if (!mutex_trylock(&head->mutex))
4445                 goto out;
4446
4447         /*
4448          * at this point we have a head with no other entries.  Go
4449          * ahead and process it.
4450          */
4451         head->node.in_tree = 0;
4452         rb_erase(&head->node.rb_node, &delayed_refs->root);
4453
4454         delayed_refs->num_entries--;
4455
4456         /*
4457          * we don't take a ref on the node because we're removing it from the
4458          * tree, so we just steal the ref the tree was holding.
4459          */
4460         delayed_refs->num_heads--;
4461         if (list_empty(&head->cluster))
4462                 delayed_refs->num_heads_ready--;
4463
4464         list_del_init(&head->cluster);
4465         spin_unlock(&delayed_refs->lock);
4466
4467         BUG_ON(head->extent_op);
4468         if (head->must_insert_reserved)
4469                 ret = 1;
4470
4471         mutex_unlock(&head->mutex);
4472         btrfs_put_delayed_ref(&head->node);
4473         return ret;
4474 out:
4475         spin_unlock(&delayed_refs->lock);
4476         return 0;
4477 }
4478
4479 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
4480                            struct btrfs_root *root,
4481                            struct extent_buffer *buf,
4482                            u64 parent, int last_ref)
4483 {
4484         struct btrfs_block_rsv *block_rsv;
4485         struct btrfs_block_group_cache *cache = NULL;
4486         int ret;
4487
4488         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4489                 ret = btrfs_add_delayed_tree_ref(trans, buf->start, buf->len,
4490                                                 parent, root->root_key.objectid,
4491                                                 btrfs_header_level(buf),
4492                                                 BTRFS_DROP_DELAYED_REF, NULL);
4493                 BUG_ON(ret);
4494         }
4495
4496         if (!last_ref)
4497                 return;
4498
4499         block_rsv = get_block_rsv(trans, root);
4500         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
4501         if (block_rsv->space_info != cache->space_info)
4502                 goto out;
4503
4504         if (btrfs_header_generation(buf) == trans->transid) {
4505                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4506                         ret = check_ref_cleanup(trans, root, buf->start);
4507                         if (!ret)
4508                                 goto pin;
4509                 }
4510
4511                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
4512                         pin_down_extent(root, cache, buf->start, buf->len, 1);
4513                         goto pin;
4514                 }
4515
4516                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
4517
4518                 btrfs_add_free_space(cache, buf->start, buf->len);
4519                 ret = update_reserved_bytes(cache, buf->len, 0, 0);
4520                 if (ret == -EAGAIN) {
4521                         /* block group became read-only */
4522                         update_reserved_bytes(cache, buf->len, 0, 1);
4523                         goto out;
4524                 }
4525
4526                 ret = 1;
4527                 spin_lock(&block_rsv->lock);
4528                 if (block_rsv->reserved < block_rsv->size) {
4529                         block_rsv->reserved += buf->len;
4530                         ret = 0;
4531                 }
4532                 spin_unlock(&block_rsv->lock);
4533
4534                 if (ret) {
4535                         spin_lock(&cache->space_info->lock);
4536                         cache->space_info->bytes_reserved -= buf->len;
4537                         spin_unlock(&cache->space_info->lock);
4538                 }
4539                 goto out;
4540         }
4541 pin:
4542         if (block_rsv->durable && !cache->ro) {
4543                 ret = 0;
4544                 spin_lock(&cache->lock);
4545                 if (!cache->ro) {
4546                         cache->reserved_pinned += buf->len;
4547                         ret = 1;
4548                 }
4549                 spin_unlock(&cache->lock);
4550
4551                 if (ret) {
4552                         spin_lock(&block_rsv->lock);
4553                         block_rsv->freed[trans->transid & 0x1] += buf->len;
4554                         spin_unlock(&block_rsv->lock);
4555                 }
4556         }
4557 out:
4558         btrfs_put_block_group(cache);
4559 }
4560
4561 int btrfs_free_extent(struct btrfs_trans_handle *trans,
4562                       struct btrfs_root *root,
4563                       u64 bytenr, u64 num_bytes, u64 parent,
4564                       u64 root_objectid, u64 owner, u64 offset)
4565 {
4566         int ret;
4567
4568         /*
4569          * tree log blocks never actually go into the extent allocation
4570          * tree, just update pinning info and exit early.
4571          */
4572         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
4573                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
4574                 /* unlocks the pinned mutex */
4575                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
4576                 ret = 0;
4577         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
4578                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
4579                                         parent, root_objectid, (int)owner,
4580                                         BTRFS_DROP_DELAYED_REF, NULL);
4581                 BUG_ON(ret);
4582         } else {
4583                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
4584                                         parent, root_objectid, owner,
4585                                         offset, BTRFS_DROP_DELAYED_REF, NULL);
4586                 BUG_ON(ret);
4587         }
4588         return ret;
4589 }
4590
4591 static u64 stripe_align(struct btrfs_root *root, u64 val)
4592 {
4593         u64 mask = ((u64)root->stripesize - 1);
4594         u64 ret = (val + mask) & ~mask;
4595         return ret;
4596 }
4597
4598 /*
4599  * when we wait for progress in the block group caching, its because
4600  * our allocation attempt failed at least once.  So, we must sleep
4601  * and let some progress happen before we try again.
4602  *
4603  * This function will sleep at least once waiting for new free space to
4604  * show up, and then it will check the block group free space numbers
4605  * for our min num_bytes.  Another option is to have it go ahead
4606  * and look in the rbtree for a free extent of a given size, but this
4607  * is a good start.
4608  */
4609 static noinline int
4610 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
4611                                 u64 num_bytes)
4612 {
4613         struct btrfs_caching_control *caching_ctl;
4614         DEFINE_WAIT(wait);
4615
4616         caching_ctl = get_caching_control(cache);
4617         if (!caching_ctl)
4618                 return 0;
4619
4620         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
4621                    (cache->free_space >= num_bytes));
4622
4623         put_caching_control(caching_ctl);
4624         return 0;
4625 }
4626
4627 static noinline int
4628 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
4629 {
4630         struct btrfs_caching_control *caching_ctl;
4631         DEFINE_WAIT(wait);
4632
4633         caching_ctl = get_caching_control(cache);
4634         if (!caching_ctl)
4635                 return 0;
4636
4637         wait_event(caching_ctl->wait, block_group_cache_done(cache));
4638
4639         put_caching_control(caching_ctl);
4640         return 0;
4641 }
4642
4643 static int get_block_group_index(struct btrfs_block_group_cache *cache)
4644 {
4645         int index;
4646         if (cache->flags & BTRFS_BLOCK_GROUP_RAID10)
4647                 index = 0;
4648         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID1)
4649                 index = 1;
4650         else if (cache->flags & BTRFS_BLOCK_GROUP_DUP)
4651                 index = 2;
4652         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID0)
4653                 index = 3;
4654         else
4655                 index = 4;
4656         return index;
4657 }
4658
4659 enum btrfs_loop_type {
4660         LOOP_FIND_IDEAL = 0,
4661         LOOP_CACHING_NOWAIT = 1,
4662         LOOP_CACHING_WAIT = 2,
4663         LOOP_ALLOC_CHUNK = 3,
4664         LOOP_NO_EMPTY_SIZE = 4,
4665 };
4666
4667 /*
4668  * walks the btree of allocated extents and find a hole of a given size.
4669  * The key ins is changed to record the hole:
4670  * ins->objectid == block start
4671  * ins->flags = BTRFS_EXTENT_ITEM_KEY
4672  * ins->offset == number of blocks
4673  * Any available blocks before search_start are skipped.
4674  */
4675 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
4676                                      struct btrfs_root *orig_root,
4677                                      u64 num_bytes, u64 empty_size,
4678                                      u64 search_start, u64 search_end,
4679                                      u64 hint_byte, struct btrfs_key *ins,
4680                                      int data)
4681 {
4682         int ret = 0;
4683         struct btrfs_root *root = orig_root->fs_info->extent_root;
4684         struct btrfs_free_cluster *last_ptr = NULL;
4685         struct btrfs_block_group_cache *block_group = NULL;
4686         int empty_cluster = 2 * 1024 * 1024;
4687         int allowed_chunk_alloc = 0;
4688         int done_chunk_alloc = 0;
4689         struct btrfs_space_info *space_info;
4690         int last_ptr_loop = 0;
4691         int loop = 0;
4692         int index = 0;
4693         bool found_uncached_bg = false;
4694         bool failed_cluster_refill = false;
4695         bool failed_alloc = false;
4696         u64 ideal_cache_percent = 0;
4697         u64 ideal_cache_offset = 0;
4698
4699         WARN_ON(num_bytes < root->sectorsize);
4700         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
4701         ins->objectid = 0;
4702         ins->offset = 0;
4703
4704         space_info = __find_space_info(root->fs_info, data);
4705         if (!space_info) {
4706                 printk(KERN_ERR "No space info for %d\n", data);
4707                 return -ENOSPC;
4708         }
4709
4710         if (orig_root->ref_cows || empty_size)
4711                 allowed_chunk_alloc = 1;
4712
4713         if (data & BTRFS_BLOCK_GROUP_METADATA) {
4714                 last_ptr = &root->fs_info->meta_alloc_cluster;
4715                 if (!btrfs_test_opt(root, SSD))
4716                         empty_cluster = 64 * 1024;
4717         }
4718
4719         if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD)) {
4720                 last_ptr = &root->fs_info->data_alloc_cluster;
4721         }
4722
4723         if (last_ptr) {
4724                 spin_lock(&last_ptr->lock);
4725                 if (last_ptr->block_group)
4726                         hint_byte = last_ptr->window_start;
4727                 spin_unlock(&last_ptr->lock);
4728         }
4729
4730         search_start = max(search_start, first_logical_byte(root, 0));
4731         search_start = max(search_start, hint_byte);
4732
4733         if (!last_ptr)
4734                 empty_cluster = 0;
4735
4736         if (search_start == hint_byte) {
4737 ideal_cache:
4738                 block_group = btrfs_lookup_block_group(root->fs_info,
4739                                                        search_start);
4740                 /*
4741                  * we don't want to use the block group if it doesn't match our
4742                  * allocation bits, or if its not cached.
4743                  *
4744                  * However if we are re-searching with an ideal block group
4745                  * picked out then we don't care that the block group is cached.
4746                  */
4747                 if (block_group && block_group_bits(block_group, data) &&
4748                     (block_group->cached != BTRFS_CACHE_NO ||
4749                      search_start == ideal_cache_offset)) {
4750                         down_read(&space_info->groups_sem);
4751                         if (list_empty(&block_group->list) ||
4752                             block_group->ro) {
4753                                 /*
4754                                  * someone is removing this block group,
4755                                  * we can't jump into the have_block_group
4756                                  * target because our list pointers are not
4757                                  * valid
4758                                  */
4759                                 btrfs_put_block_group(block_group);
4760                                 up_read(&space_info->groups_sem);
4761                         } else {
4762                                 index = get_block_group_index(block_group);
4763                                 goto have_block_group;
4764                         }
4765                 } else if (block_group) {
4766                         btrfs_put_block_group(block_group);
4767                 }
4768         }
4769 search:
4770         down_read(&space_info->groups_sem);
4771         list_for_each_entry(block_group, &space_info->block_groups[index],
4772                             list) {
4773                 u64 offset;
4774                 int cached;
4775
4776                 btrfs_get_block_group(block_group);
4777                 search_start = block_group->key.objectid;
4778
4779 have_block_group:
4780                 if (unlikely(block_group->cached == BTRFS_CACHE_NO)) {
4781                         u64 free_percent;
4782
4783                         free_percent = btrfs_block_group_used(&block_group->item);
4784                         free_percent *= 100;
4785                         free_percent = div64_u64(free_percent,
4786                                                  block_group->key.offset);
4787                         free_percent = 100 - free_percent;
4788                         if (free_percent > ideal_cache_percent &&
4789                             likely(!block_group->ro)) {
4790                                 ideal_cache_offset = block_group->key.objectid;
4791                                 ideal_cache_percent = free_percent;
4792                         }
4793
4794                         /*
4795                          * We only want to start kthread caching if we are at
4796                          * the point where we will wait for caching to make
4797                          * progress, or if our ideal search is over and we've
4798                          * found somebody to start caching.
4799                          */
4800                         if (loop > LOOP_CACHING_NOWAIT ||
4801                             (loop > LOOP_FIND_IDEAL &&
4802                              atomic_read(&space_info->caching_threads) < 2)) {
4803                                 ret = cache_block_group(block_group);
4804                                 BUG_ON(ret);
4805                         }
4806                         found_uncached_bg = true;
4807
4808                         /*
4809                          * If loop is set for cached only, try the next block
4810                          * group.
4811                          */
4812                         if (loop == LOOP_FIND_IDEAL)
4813                                 goto loop;
4814                 }
4815
4816                 cached = block_group_cache_done(block_group);
4817                 if (unlikely(!cached))
4818                         found_uncached_bg = true;
4819
4820                 if (unlikely(block_group->ro))
4821                         goto loop;
4822
4823                 /*
4824                  * Ok we want to try and use the cluster allocator, so lets look
4825                  * there, unless we are on LOOP_NO_EMPTY_SIZE, since we will
4826                  * have tried the cluster allocator plenty of times at this
4827                  * point and not have found anything, so we are likely way too
4828                  * fragmented for the clustering stuff to find anything, so lets
4829                  * just skip it and let the allocator find whatever block it can
4830                  * find
4831                  */
4832                 if (last_ptr && loop < LOOP_NO_EMPTY_SIZE) {
4833                         /*
4834                          * the refill lock keeps out other
4835                          * people trying to start a new cluster
4836                          */
4837                         spin_lock(&last_ptr->refill_lock);
4838                         if (last_ptr->block_group &&
4839                             (last_ptr->block_group->ro ||
4840                             !block_group_bits(last_ptr->block_group, data))) {
4841                                 offset = 0;
4842                                 goto refill_cluster;
4843                         }
4844
4845                         offset = btrfs_alloc_from_cluster(block_group, last_ptr,
4846                                                  num_bytes, search_start);
4847                         if (offset) {
4848                                 /* we have a block, we're done */
4849                                 spin_unlock(&last_ptr->refill_lock);
4850                                 goto checks;
4851                         }
4852
4853                         spin_lock(&last_ptr->lock);
4854                         /*
4855                          * whoops, this cluster doesn't actually point to
4856                          * this block group.  Get a ref on the block
4857                          * group is does point to and try again
4858                          */
4859                         if (!last_ptr_loop && last_ptr->block_group &&
4860                             last_ptr->block_group != block_group) {
4861
4862                                 btrfs_put_block_group(block_group);
4863                                 block_group = last_ptr->block_group;
4864                                 btrfs_get_block_group(block_group);
4865                                 spin_unlock(&last_ptr->lock);
4866                                 spin_unlock(&last_ptr->refill_lock);
4867
4868                                 last_ptr_loop = 1;
4869                                 search_start = block_group->key.objectid;
4870                                 /*
4871                                  * we know this block group is properly
4872                                  * in the list because
4873                                  * btrfs_remove_block_group, drops the
4874                                  * cluster before it removes the block
4875                                  * group from the list
4876                                  */
4877                                 goto have_block_group;
4878                         }
4879                         spin_unlock(&last_ptr->lock);
4880 refill_cluster:
4881                         /*
4882                          * this cluster didn't work out, free it and
4883                          * start over
4884                          */
4885                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
4886
4887                         last_ptr_loop = 0;
4888
4889                         /* allocate a cluster in this block group */
4890                         ret = btrfs_find_space_cluster(trans, root,
4891                                                block_group, last_ptr,
4892                                                offset, num_bytes,
4893                                                empty_cluster + empty_size);
4894                         if (ret == 0) {
4895                                 /*
4896                                  * now pull our allocation out of this
4897                                  * cluster
4898                                  */
4899                                 offset = btrfs_alloc_from_cluster(block_group,
4900                                                   last_ptr, num_bytes,
4901                                                   search_start);
4902                                 if (offset) {
4903                                         /* we found one, proceed */
4904                                         spin_unlock(&last_ptr->refill_lock);
4905                                         goto checks;
4906                                 }
4907                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
4908                                    && !failed_cluster_refill) {
4909                                 spin_unlock(&last_ptr->refill_lock);
4910
4911                                 failed_cluster_refill = true;
4912                                 wait_block_group_cache_progress(block_group,
4913                                        num_bytes + empty_cluster + empty_size);
4914                                 goto have_block_group;
4915                         }
4916
4917                         /*
4918                          * at this point we either didn't find a cluster
4919                          * or we weren't able to allocate a block from our
4920                          * cluster.  Free the cluster we've been trying
4921                          * to use, and go to the next block group
4922                          */
4923                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
4924                         spin_unlock(&last_ptr->refill_lock);
4925                         goto loop;
4926                 }
4927
4928                 offset = btrfs_find_space_for_alloc(block_group, search_start,
4929                                                     num_bytes, empty_size);
4930                 /*
4931                  * If we didn't find a chunk, and we haven't failed on this
4932                  * block group before, and this block group is in the middle of
4933                  * caching and we are ok with waiting, then go ahead and wait
4934                  * for progress to be made, and set failed_alloc to true.
4935                  *
4936                  * If failed_alloc is true then we've already waited on this
4937                  * block group once and should move on to the next block group.
4938                  */
4939                 if (!offset && !failed_alloc && !cached &&
4940                     loop > LOOP_CACHING_NOWAIT) {
4941                         wait_block_group_cache_progress(block_group,
4942                                                 num_bytes + empty_size);
4943                         failed_alloc = true;
4944                         goto have_block_group;
4945                 } else if (!offset) {
4946                         goto loop;
4947                 }
4948 checks:
4949                 search_start = stripe_align(root, offset);
4950                 /* move on to the next group */
4951                 if (search_start + num_bytes >= search_end) {
4952                         btrfs_add_free_space(block_group, offset, num_bytes);
4953                         goto loop;
4954                 }
4955
4956                 /* move on to the next group */
4957                 if (search_start + num_bytes >
4958                     block_group->key.objectid + block_group->key.offset) {
4959                         btrfs_add_free_space(block_group, offset, num_bytes);
4960                         goto loop;
4961                 }
4962
4963                 ins->objectid = search_start;
4964                 ins->offset = num_bytes;
4965
4966                 if (offset < search_start)
4967                         btrfs_add_free_space(block_group, offset,
4968                                              search_start - offset);
4969                 BUG_ON(offset > search_start);
4970
4971                 ret = update_reserved_bytes(block_group, num_bytes, 1,
4972                                             (data & BTRFS_BLOCK_GROUP_DATA));
4973                 if (ret == -EAGAIN) {
4974                         btrfs_add_free_space(block_group, offset, num_bytes);
4975                         goto loop;
4976                 }
4977
4978                 /* we are all good, lets return */
4979                 ins->objectid = search_start;
4980                 ins->offset = num_bytes;
4981
4982                 if (offset < search_start)
4983                         btrfs_add_free_space(block_group, offset,
4984                                              search_start - offset);
4985                 BUG_ON(offset > search_start);
4986                 break;
4987 loop:
4988                 failed_cluster_refill = false;
4989                 failed_alloc = false;
4990                 BUG_ON(index != get_block_group_index(block_group));
4991                 btrfs_put_block_group(block_group);
4992         }
4993         up_read(&space_info->groups_sem);
4994
4995         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
4996                 goto search;
4997
4998         /* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
4999          *                      for them to make caching progress.  Also
5000          *                      determine the best possible bg to cache
5001          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5002          *                      caching kthreads as we move along
5003          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5004          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5005          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5006          *                      again
5007          */
5008         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE &&
5009             (found_uncached_bg || empty_size || empty_cluster ||
5010              allowed_chunk_alloc)) {
5011                 index = 0;
5012                 if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
5013                         found_uncached_bg = false;
5014                         loop++;
5015                         if (!ideal_cache_percent &&
5016                             atomic_read(&space_info->caching_threads))
5017                                 goto search;
5018
5019                         /*
5020                          * 1 of the following 2 things have happened so far
5021                          *
5022                          * 1) We found an ideal block group for caching that
5023                          * is mostly full and will cache quickly, so we might
5024                          * as well wait for it.
5025                          *
5026                          * 2) We searched for cached only and we didn't find
5027                          * anything, and we didn't start any caching kthreads
5028                          * either, so chances are we will loop through and
5029                          * start a couple caching kthreads, and then come back
5030                          * around and just wait for them.  This will be slower
5031                          * because we will have 2 caching kthreads reading at
5032                          * the same time when we could have just started one
5033                          * and waited for it to get far enough to give us an
5034                          * allocation, so go ahead and go to the wait caching
5035                          * loop.
5036                          */
5037                         loop = LOOP_CACHING_WAIT;
5038                         search_start = ideal_cache_offset;
5039                         ideal_cache_percent = 0;
5040                         goto ideal_cache;
5041                 } else if (loop == LOOP_FIND_IDEAL) {
5042                         /*
5043                          * Didn't find a uncached bg, wait on anything we find
5044                          * next.
5045                          */
5046                         loop = LOOP_CACHING_WAIT;
5047                         goto search;
5048                 }
5049
5050                 if (loop < LOOP_CACHING_WAIT) {
5051                         loop++;
5052                         goto search;
5053                 }
5054
5055                 if (loop == LOOP_ALLOC_CHUNK) {
5056                         empty_size = 0;
5057                         empty_cluster = 0;
5058                 }
5059
5060                 if (allowed_chunk_alloc) {
5061                         ret = do_chunk_alloc(trans, root, num_bytes +
5062                                              2 * 1024 * 1024, data, 1);
5063                         allowed_chunk_alloc = 0;
5064                         done_chunk_alloc = 1;
5065                 } else if (!done_chunk_alloc) {
5066                         space_info->force_alloc = 1;
5067                 }
5068
5069                 if (loop < LOOP_NO_EMPTY_SIZE) {
5070                         loop++;
5071                         goto search;
5072                 }
5073                 ret = -ENOSPC;
5074         } else if (!ins->objectid) {
5075                 ret = -ENOSPC;
5076         }
5077
5078         /* we found what we needed */
5079         if (ins->objectid) {
5080                 if (!(data & BTRFS_BLOCK_GROUP_DATA))
5081                         trans->block_group = block_group->key.objectid;
5082
5083                 btrfs_put_block_group(block_group);
5084                 ret = 0;
5085         }
5086
5087         return ret;
5088 }
5089
5090 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5091                             int dump_block_groups)
5092 {
5093         struct btrfs_block_group_cache *cache;
5094         int index = 0;
5095
5096         spin_lock(&info->lock);
5097         printk(KERN_INFO "space_info has %llu free, is %sfull\n",
5098                (unsigned long long)(info->total_bytes - info->bytes_used -
5099                                     info->bytes_pinned - info->bytes_reserved -
5100                                     info->bytes_readonly),
5101                (info->full) ? "" : "not ");
5102         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5103                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5104                (unsigned long long)info->total_bytes,
5105                (unsigned long long)info->bytes_used,
5106                (unsigned long long)info->bytes_pinned,
5107                (unsigned long long)info->bytes_reserved,
5108                (unsigned long long)info->bytes_may_use,
5109                (unsigned long long)info->bytes_readonly);
5110         spin_unlock(&info->lock);
5111
5112         if (!dump_block_groups)
5113                 return;
5114
5115         down_read(&info->groups_sem);
5116 again:
5117         list_for_each_entry(cache, &info->block_groups[index], list) {
5118                 spin_lock(&cache->lock);
5119                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
5120                        "%llu pinned %llu reserved\n",
5121                        (unsigned long long)cache->key.objectid,
5122                        (unsigned long long)cache->key.offset,
5123                        (unsigned long long)btrfs_block_group_used(&cache->item),
5124                        (unsigned long long)cache->pinned,
5125                        (unsigned long long)cache->reserved);
5126                 btrfs_dump_free_space(cache, bytes);
5127                 spin_unlock(&cache->lock);
5128         }
5129         if (++index < BTRFS_NR_RAID_TYPES)
5130                 goto again;
5131         up_read(&info->groups_sem);
5132 }
5133
5134 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5135                          struct btrfs_root *root,
5136                          u64 num_bytes, u64 min_alloc_size,
5137                          u64 empty_size, u64 hint_byte,
5138                          u64 search_end, struct btrfs_key *ins,
5139                          u64 data)
5140 {
5141         int ret;
5142         u64 search_start = 0;
5143
5144         data = btrfs_get_alloc_profile(root, data);
5145 again:
5146         /*
5147          * the only place that sets empty_size is btrfs_realloc_node, which
5148          * is not called recursively on allocations
5149          */
5150         if (empty_size || root->ref_cows)
5151                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5152                                      num_bytes + 2 * 1024 * 1024, data, 0);
5153
5154         WARN_ON(num_bytes < root->sectorsize);
5155         ret = find_free_extent(trans, root, num_bytes, empty_size,
5156                                search_start, search_end, hint_byte,
5157                                ins, data);
5158
5159         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
5160                 num_bytes = num_bytes >> 1;
5161                 num_bytes = num_bytes & ~(root->sectorsize - 1);
5162                 num_bytes = max(num_bytes, min_alloc_size);
5163                 do_chunk_alloc(trans, root->fs_info->extent_root,
5164                                num_bytes, data, 1);
5165                 goto again;
5166         }
5167         if (ret == -ENOSPC) {
5168                 struct btrfs_space_info *sinfo;
5169
5170                 sinfo = __find_space_info(root->fs_info, data);
5171                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
5172                        "wanted %llu\n", (unsigned long long)data,
5173                        (unsigned long long)num_bytes);
5174                 dump_space_info(sinfo, num_bytes, 1);
5175         }
5176
5177         return ret;
5178 }
5179
5180 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
5181 {
5182         struct btrfs_block_group_cache *cache;
5183         int ret = 0;
5184
5185         cache = btrfs_lookup_block_group(root->fs_info, start);
5186         if (!cache) {
5187                 printk(KERN_ERR "Unable to find block group for %llu\n",
5188                        (unsigned long long)start);
5189                 return -ENOSPC;
5190         }
5191
5192         ret = btrfs_discard_extent(root, start, len);
5193
5194         btrfs_add_free_space(cache, start, len);
5195         update_reserved_bytes(cache, len, 0, 1);
5196         btrfs_put_block_group(cache);
5197
5198         return ret;
5199 }
5200
5201 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5202                                       struct btrfs_root *root,
5203                                       u64 parent, u64 root_objectid,
5204                                       u64 flags, u64 owner, u64 offset,
5205                                       struct btrfs_key *ins, int ref_mod)
5206 {
5207         int ret;
5208         struct btrfs_fs_info *fs_info = root->fs_info;
5209         struct btrfs_extent_item *extent_item;
5210         struct btrfs_extent_inline_ref *iref;
5211         struct btrfs_path *path;
5212         struct extent_buffer *leaf;
5213         int type;
5214         u32 size;
5215
5216         if (parent > 0)
5217                 type = BTRFS_SHARED_DATA_REF_KEY;
5218         else
5219                 type = BTRFS_EXTENT_DATA_REF_KEY;
5220
5221         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
5222
5223         path = btrfs_alloc_path();
5224         BUG_ON(!path);
5225
5226         path->leave_spinning = 1;
5227         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5228                                       ins, size);
5229         BUG_ON(ret);
5230
5231         leaf = path->nodes[0];
5232         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5233                                      struct btrfs_extent_item);
5234         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
5235         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5236         btrfs_set_extent_flags(leaf, extent_item,
5237                                flags | BTRFS_EXTENT_FLAG_DATA);
5238
5239         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
5240         btrfs_set_extent_inline_ref_type(leaf, iref, type);
5241         if (parent > 0) {
5242                 struct btrfs_shared_data_ref *ref;
5243                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
5244                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5245                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
5246         } else {
5247                 struct btrfs_extent_data_ref *ref;
5248                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
5249                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
5250                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
5251                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
5252                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
5253         }
5254
5255         btrfs_mark_buffer_dirty(path->nodes[0]);
5256         btrfs_free_path(path);
5257
5258         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5259         if (ret) {
5260                 printk(KERN_ERR "btrfs update block group failed for %llu "
5261                        "%llu\n", (unsigned long long)ins->objectid,
5262                        (unsigned long long)ins->offset);
5263                 BUG();
5264         }
5265         return ret;
5266 }
5267
5268 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
5269                                      struct btrfs_root *root,
5270                                      u64 parent, u64 root_objectid,
5271                                      u64 flags, struct btrfs_disk_key *key,
5272                                      int level, struct btrfs_key *ins)
5273 {
5274         int ret;
5275         struct btrfs_fs_info *fs_info = root->fs_info;
5276         struct btrfs_extent_item *extent_item;
5277         struct btrfs_tree_block_info *block_info;
5278         struct btrfs_extent_inline_ref *iref;
5279         struct btrfs_path *path;
5280         struct extent_buffer *leaf;
5281         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
5282
5283         path = btrfs_alloc_path();
5284         BUG_ON(!path);
5285
5286         path->leave_spinning = 1;
5287         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5288                                       ins, size);
5289         BUG_ON(ret);
5290
5291         leaf = path->nodes[0];
5292         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5293                                      struct btrfs_extent_item);
5294         btrfs_set_extent_refs(leaf, extent_item, 1);
5295         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5296         btrfs_set_extent_flags(leaf, extent_item,
5297                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
5298         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
5299
5300         btrfs_set_tree_block_key(leaf, block_info, key);
5301         btrfs_set_tree_block_level(leaf, block_info, level);
5302
5303         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
5304         if (parent > 0) {
5305                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
5306                 btrfs_set_extent_inline_ref_type(leaf, iref,
5307                                                  BTRFS_SHARED_BLOCK_REF_KEY);
5308                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5309         } else {
5310                 btrfs_set_extent_inline_ref_type(leaf, iref,
5311                                                  BTRFS_TREE_BLOCK_REF_KEY);
5312                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
5313         }
5314
5315         btrfs_mark_buffer_dirty(leaf);
5316         btrfs_free_path(path);
5317
5318         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5319         if (ret) {
5320                 printk(KERN_ERR "btrfs update block group failed for %llu "
5321                        "%llu\n", (unsigned long long)ins->objectid,
5322                        (unsigned long long)ins->offset);
5323                 BUG();
5324         }
5325         return ret;
5326 }
5327
5328 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5329                                      struct btrfs_root *root,
5330                                      u64 root_objectid, u64 owner,
5331                                      u64 offset, struct btrfs_key *ins)
5332 {
5333         int ret;
5334
5335         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
5336
5337         ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
5338                                          0, root_objectid, owner, offset,
5339                                          BTRFS_ADD_DELAYED_EXTENT, NULL);
5340         return ret;
5341 }
5342
5343 /*
5344  * this is used by the tree logging recovery code.  It records that
5345  * an extent has been allocated and makes sure to clear the free
5346  * space cache bits as well
5347  */
5348 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
5349                                    struct btrfs_root *root,
5350                                    u64 root_objectid, u64 owner, u64 offset,
5351                                    struct btrfs_key *ins)
5352 {
5353         int ret;
5354         struct btrfs_block_group_cache *block_group;
5355         struct btrfs_caching_control *caching_ctl;
5356         u64 start = ins->objectid;
5357         u64 num_bytes = ins->offset;
5358
5359         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
5360         cache_block_group(block_group);
5361         caching_ctl = get_caching_control(block_group);
5362
5363         if (!caching_ctl) {
5364                 BUG_ON(!block_group_cache_done(block_group));
5365                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5366                 BUG_ON(ret);
5367         } else {
5368                 mutex_lock(&caching_ctl->mutex);
5369
5370                 if (start >= caching_ctl->progress) {
5371                         ret = add_excluded_extent(root, start, num_bytes);
5372                         BUG_ON(ret);
5373                 } else if (start + num_bytes <= caching_ctl->progress) {
5374                         ret = btrfs_remove_free_space(block_group,
5375                                                       start, num_bytes);
5376                         BUG_ON(ret);
5377                 } else {
5378                         num_bytes = caching_ctl->progress - start;
5379                         ret = btrfs_remove_free_space(block_group,
5380                                                       start, num_bytes);
5381                         BUG_ON(ret);
5382
5383                         start = caching_ctl->progress;
5384                         num_bytes = ins->objectid + ins->offset -
5385                                     caching_ctl->progress;
5386                         ret = add_excluded_extent(root, start, num_bytes);
5387                         BUG_ON(ret);
5388                 }
5389
5390                 mutex_unlock(&caching_ctl->mutex);
5391                 put_caching_control(caching_ctl);
5392         }
5393
5394         ret = update_reserved_bytes(block_group, ins->offset, 1, 1);
5395         BUG_ON(ret);
5396         btrfs_put_block_group(block_group);
5397         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
5398                                          0, owner, offset, ins, 1);
5399         return ret;
5400 }
5401
5402 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
5403                                             struct btrfs_root *root,
5404                                             u64 bytenr, u32 blocksize,
5405                                             int level)
5406 {
5407         struct extent_buffer *buf;
5408
5409         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
5410         if (!buf)
5411                 return ERR_PTR(-ENOMEM);
5412         btrfs_set_header_generation(buf, trans->transid);
5413         btrfs_set_buffer_lockdep_class(buf, level);
5414         btrfs_tree_lock(buf);
5415         clean_tree_block(trans, root, buf);
5416
5417         btrfs_set_lock_blocking(buf);
5418         btrfs_set_buffer_uptodate(buf);
5419
5420         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
5421                 /*
5422                  * we allow two log transactions at a time, use different
5423                  * EXENT bit to differentiate dirty pages.
5424                  */
5425                 if (root->log_transid % 2 == 0)
5426                         set_extent_dirty(&root->dirty_log_pages, buf->start,
5427                                         buf->start + buf->len - 1, GFP_NOFS);
5428                 else
5429                         set_extent_new(&root->dirty_log_pages, buf->start,
5430                                         buf->start + buf->len - 1, GFP_NOFS);
5431         } else {
5432                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
5433                          buf->start + buf->len - 1, GFP_NOFS);
5434         }
5435         trans->blocks_used++;
5436         /* this returns a buffer locked for blocking */
5437         return buf;
5438 }
5439
5440 static struct btrfs_block_rsv *
5441 use_block_rsv(struct btrfs_trans_handle *trans,
5442               struct btrfs_root *root, u32 blocksize)
5443 {
5444         struct btrfs_block_rsv *block_rsv;
5445         int ret;
5446
5447         block_rsv = get_block_rsv(trans, root);
5448
5449         if (block_rsv->size == 0) {
5450                 ret = reserve_metadata_bytes(block_rsv, blocksize);
5451                 if (ret)
5452                         return ERR_PTR(ret);
5453                 return block_rsv;
5454         }
5455
5456         ret = block_rsv_use_bytes(block_rsv, blocksize);
5457         if (!ret)
5458                 return block_rsv;
5459
5460         WARN_ON(1);
5461         printk(KERN_INFO"block_rsv size %llu reserved %llu freed %llu %llu\n",
5462                 block_rsv->size, block_rsv->reserved,
5463                 block_rsv->freed[0], block_rsv->freed[1]);
5464
5465         return ERR_PTR(-ENOSPC);
5466 }
5467
5468 static void unuse_block_rsv(struct btrfs_block_rsv *block_rsv, u32 blocksize)
5469 {
5470         block_rsv_add_bytes(block_rsv, blocksize, 0);
5471         block_rsv_release_bytes(block_rsv, NULL, 0);
5472 }
5473
5474 /*
5475  * finds a free extent and does all the dirty work required for allocation
5476  * returns the key for the extent through ins, and a tree buffer for
5477  * the first block of the extent through buf.
5478  *
5479  * returns the tree buffer or NULL.
5480  */
5481 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
5482                                         struct btrfs_root *root, u32 blocksize,
5483                                         u64 parent, u64 root_objectid,
5484                                         struct btrfs_disk_key *key, int level,
5485                                         u64 hint, u64 empty_size)
5486 {
5487         struct btrfs_key ins;
5488         struct btrfs_block_rsv *block_rsv;
5489         struct extent_buffer *buf;
5490         u64 flags = 0;
5491         int ret;
5492
5493
5494         block_rsv = use_block_rsv(trans, root, blocksize);
5495         if (IS_ERR(block_rsv))
5496                 return ERR_CAST(block_rsv);
5497
5498         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
5499                                    empty_size, hint, (u64)-1, &ins, 0);
5500         if (ret) {
5501                 unuse_block_rsv(block_rsv, blocksize);
5502                 return ERR_PTR(ret);
5503         }
5504
5505         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
5506                                     blocksize, level);
5507         BUG_ON(IS_ERR(buf));
5508
5509         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
5510                 if (parent == 0)
5511                         parent = ins.objectid;
5512                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
5513         } else
5514                 BUG_ON(parent > 0);
5515
5516         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
5517                 struct btrfs_delayed_extent_op *extent_op;
5518                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
5519                 BUG_ON(!extent_op);
5520                 if (key)
5521                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
5522                 else
5523                         memset(&extent_op->key, 0, sizeof(extent_op->key));
5524                 extent_op->flags_to_set = flags;
5525                 extent_op->update_key = 1;
5526                 extent_op->update_flags = 1;
5527                 extent_op->is_data = 0;
5528
5529                 ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
5530                                         ins.offset, parent, root_objectid,
5531                                         level, BTRFS_ADD_DELAYED_EXTENT,
5532                                         extent_op);
5533                 BUG_ON(ret);
5534         }
5535         return buf;
5536 }
5537
5538 struct walk_control {
5539         u64 refs[BTRFS_MAX_LEVEL];
5540         u64 flags[BTRFS_MAX_LEVEL];
5541         struct btrfs_key update_progress;
5542         int stage;
5543         int level;
5544         int shared_level;
5545         int update_ref;
5546         int keep_locks;
5547         int reada_slot;
5548         int reada_count;
5549 };
5550
5551 #define DROP_REFERENCE  1
5552 #define UPDATE_BACKREF  2
5553
5554 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
5555                                      struct btrfs_root *root,
5556                                      struct walk_control *wc,
5557                                      struct btrfs_path *path)
5558 {
5559         u64 bytenr;
5560         u64 generation;
5561         u64 refs;
5562         u64 flags;
5563         u64 last = 0;
5564         u32 nritems;
5565         u32 blocksize;
5566         struct btrfs_key key;
5567         struct extent_buffer *eb;
5568         int ret;
5569         int slot;
5570         int nread = 0;
5571
5572         if (path->slots[wc->level] < wc->reada_slot) {
5573                 wc->reada_count = wc->reada_count * 2 / 3;
5574                 wc->reada_count = max(wc->reada_count, 2);
5575         } else {
5576                 wc->reada_count = wc->reada_count * 3 / 2;
5577                 wc->reada_count = min_t(int, wc->reada_count,
5578                                         BTRFS_NODEPTRS_PER_BLOCK(root));
5579         }
5580
5581         eb = path->nodes[wc->level];
5582         nritems = btrfs_header_nritems(eb);
5583         blocksize = btrfs_level_size(root, wc->level - 1);
5584
5585         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
5586                 if (nread >= wc->reada_count)
5587                         break;
5588
5589                 cond_resched();
5590                 bytenr = btrfs_node_blockptr(eb, slot);
5591                 generation = btrfs_node_ptr_generation(eb, slot);
5592
5593                 if (slot == path->slots[wc->level])
5594                         goto reada;
5595
5596                 if (wc->stage == UPDATE_BACKREF &&
5597                     generation <= root->root_key.offset)
5598                         continue;
5599
5600                 /* We don't lock the tree block, it's OK to be racy here */
5601                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
5602                                                &refs, &flags);
5603                 BUG_ON(ret);
5604                 BUG_ON(refs == 0);
5605
5606                 if (wc->stage == DROP_REFERENCE) {
5607                         if (refs == 1)
5608                                 goto reada;
5609
5610                         if (wc->level == 1 &&
5611                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5612                                 continue;
5613                         if (!wc->update_ref ||
5614                             generation <= root->root_key.offset)
5615                                 continue;
5616                         btrfs_node_key_to_cpu(eb, &key, slot);
5617                         ret = btrfs_comp_cpu_keys(&key,
5618                                                   &wc->update_progress);
5619                         if (ret < 0)
5620                                 continue;
5621                 } else {
5622                         if (wc->level == 1 &&
5623                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5624                                 continue;
5625                 }
5626 reada:
5627                 ret = readahead_tree_block(root, bytenr, blocksize,
5628                                            generation);
5629                 if (ret)
5630                         break;
5631                 last = bytenr + blocksize;
5632                 nread++;
5633         }
5634         wc->reada_slot = slot;
5635 }
5636
5637 /*
5638  * hepler to process tree block while walking down the tree.
5639  *
5640  * when wc->stage == UPDATE_BACKREF, this function updates
5641  * back refs for pointers in the block.
5642  *
5643  * NOTE: return value 1 means we should stop walking down.
5644  */
5645 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
5646                                    struct btrfs_root *root,
5647                                    struct btrfs_path *path,
5648                                    struct walk_control *wc, int lookup_info)
5649 {
5650         int level = wc->level;
5651         struct extent_buffer *eb = path->nodes[level];
5652         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5653         int ret;
5654
5655         if (wc->stage == UPDATE_BACKREF &&
5656             btrfs_header_owner(eb) != root->root_key.objectid)
5657                 return 1;
5658
5659         /*
5660          * when reference count of tree block is 1, it won't increase
5661          * again. once full backref flag is set, we never clear it.
5662          */
5663         if (lookup_info &&
5664             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
5665              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
5666                 BUG_ON(!path->locks[level]);
5667                 ret = btrfs_lookup_extent_info(trans, root,
5668                                                eb->start, eb->len,
5669                                                &wc->refs[level],
5670                                                &wc->flags[level]);
5671                 BUG_ON(ret);
5672                 BUG_ON(wc->refs[level] == 0);
5673         }
5674
5675         if (wc->stage == DROP_REFERENCE) {
5676                 if (wc->refs[level] > 1)
5677                         return 1;
5678
5679                 if (path->locks[level] && !wc->keep_locks) {
5680                         btrfs_tree_unlock(eb);
5681                         path->locks[level] = 0;
5682                 }
5683                 return 0;
5684         }
5685
5686         /* wc->stage == UPDATE_BACKREF */
5687         if (!(wc->flags[level] & flag)) {
5688                 BUG_ON(!path->locks[level]);
5689                 ret = btrfs_inc_ref(trans, root, eb, 1);
5690                 BUG_ON(ret);
5691                 ret = btrfs_dec_ref(trans, root, eb, 0);
5692                 BUG_ON(ret);
5693                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
5694                                                   eb->len, flag, 0);
5695                 BUG_ON(ret);
5696                 wc->flags[level] |= flag;
5697         }
5698
5699         /*
5700          * the block is shared by multiple trees, so it's not good to
5701          * keep the tree lock
5702          */
5703         if (path->locks[level] && level > 0) {
5704                 btrfs_tree_unlock(eb);
5705                 path->locks[level] = 0;
5706         }
5707         return 0;
5708 }
5709
5710 /*
5711  * hepler to process tree block pointer.
5712  *
5713  * when wc->stage == DROP_REFERENCE, this function checks
5714  * reference count of the block pointed to. if the block
5715  * is shared and we need update back refs for the subtree
5716  * rooted at the block, this function changes wc->stage to
5717  * UPDATE_BACKREF. if the block is shared and there is no
5718  * need to update back, this function drops the reference
5719  * to the block.
5720  *
5721  * NOTE: return value 1 means we should stop walking down.
5722  */
5723 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
5724                                  struct btrfs_root *root,
5725                                  struct btrfs_path *path,
5726                                  struct walk_control *wc, int *lookup_info)
5727 {
5728         u64 bytenr;
5729         u64 generation;
5730         u64 parent;
5731         u32 blocksize;
5732         struct btrfs_key key;
5733         struct extent_buffer *next;
5734         int level = wc->level;
5735         int reada = 0;
5736         int ret = 0;
5737
5738         generation = btrfs_node_ptr_generation(path->nodes[level],
5739                                                path->slots[level]);
5740         /*
5741          * if the lower level block was created before the snapshot
5742          * was created, we know there is no need to update back refs
5743          * for the subtree
5744          */
5745         if (wc->stage == UPDATE_BACKREF &&
5746             generation <= root->root_key.offset) {
5747                 *lookup_info = 1;
5748                 return 1;
5749         }
5750
5751         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
5752         blocksize = btrfs_level_size(root, level - 1);
5753
5754         next = btrfs_find_tree_block(root, bytenr, blocksize);
5755         if (!next) {
5756                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
5757                 if (!next)
5758                         return -ENOMEM;
5759                 reada = 1;
5760         }
5761         btrfs_tree_lock(next);
5762         btrfs_set_lock_blocking(next);
5763
5764         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
5765                                        &wc->refs[level - 1],
5766                                        &wc->flags[level - 1]);
5767         BUG_ON(ret);
5768         BUG_ON(wc->refs[level - 1] == 0);
5769         *lookup_info = 0;
5770
5771         if (wc->stage == DROP_REFERENCE) {
5772                 if (wc->refs[level - 1] > 1) {
5773                         if (level == 1 &&
5774                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5775                                 goto skip;
5776
5777                         if (!wc->update_ref ||
5778                             generation <= root->root_key.offset)
5779                                 goto skip;
5780
5781                         btrfs_node_key_to_cpu(path->nodes[level], &key,
5782                                               path->slots[level]);
5783                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
5784                         if (ret < 0)
5785                                 goto skip;
5786
5787                         wc->stage = UPDATE_BACKREF;
5788                         wc->shared_level = level - 1;
5789                 }
5790         } else {
5791                 if (level == 1 &&
5792                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5793                         goto skip;
5794         }
5795
5796         if (!btrfs_buffer_uptodate(next, generation)) {
5797                 btrfs_tree_unlock(next);
5798                 free_extent_buffer(next);
5799                 next = NULL;
5800                 *lookup_info = 1;
5801         }
5802
5803         if (!next) {
5804                 if (reada && level == 1)
5805                         reada_walk_down(trans, root, wc, path);
5806                 next = read_tree_block(root, bytenr, blocksize, generation);
5807                 btrfs_tree_lock(next);
5808                 btrfs_set_lock_blocking(next);
5809         }
5810
5811         level--;
5812         BUG_ON(level != btrfs_header_level(next));
5813         path->nodes[level] = next;
5814         path->slots[level] = 0;
5815         path->locks[level] = 1;
5816         wc->level = level;
5817         if (wc->level == 1)
5818                 wc->reada_slot = 0;
5819         return 0;
5820 skip:
5821         wc->refs[level - 1] = 0;
5822         wc->flags[level - 1] = 0;
5823         if (wc->stage == DROP_REFERENCE) {
5824                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
5825                         parent = path->nodes[level]->start;
5826                 } else {
5827                         BUG_ON(root->root_key.objectid !=
5828                                btrfs_header_owner(path->nodes[level]));
5829                         parent = 0;
5830                 }
5831
5832                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
5833                                         root->root_key.objectid, level - 1, 0);
5834                 BUG_ON(ret);
5835         }
5836         btrfs_tree_unlock(next);
5837         free_extent_buffer(next);
5838         *lookup_info = 1;
5839         return 1;
5840 }
5841
5842 /*
5843  * hepler to process tree block while walking up the tree.
5844  *
5845  * when wc->stage == DROP_REFERENCE, this function drops
5846  * reference count on the block.
5847  *
5848  * when wc->stage == UPDATE_BACKREF, this function changes
5849  * wc->stage back to DROP_REFERENCE if we changed wc->stage
5850  * to UPDATE_BACKREF previously while processing the block.
5851  *
5852  * NOTE: return value 1 means we should stop walking up.
5853  */
5854 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
5855                                  struct btrfs_root *root,
5856                                  struct btrfs_path *path,
5857                                  struct walk_control *wc)
5858 {
5859         int ret;
5860         int level = wc->level;
5861         struct extent_buffer *eb = path->nodes[level];
5862         u64 parent = 0;
5863
5864         if (wc->stage == UPDATE_BACKREF) {
5865                 BUG_ON(wc->shared_level < level);
5866                 if (level < wc->shared_level)
5867                         goto out;
5868
5869                 ret = find_next_key(path, level + 1, &wc->update_progress);
5870                 if (ret > 0)
5871                         wc->update_ref = 0;
5872
5873                 wc->stage = DROP_REFERENCE;
5874                 wc->shared_level = -1;
5875                 path->slots[level] = 0;
5876
5877                 /*
5878                  * check reference count again if the block isn't locked.
5879                  * we should start walking down the tree again if reference
5880                  * count is one.
5881                  */
5882                 if (!path->locks[level]) {
5883                         BUG_ON(level == 0);
5884                         btrfs_tree_lock(eb);
5885                         btrfs_set_lock_blocking(eb);
5886                         path->locks[level] = 1;
5887
5888                         ret = btrfs_lookup_extent_info(trans, root,
5889                                                        eb->start, eb->len,
5890                                                        &wc->refs[level],
5891                                                        &wc->flags[level]);
5892                         BUG_ON(ret);
5893                         BUG_ON(wc->refs[level] == 0);
5894                         if (wc->refs[level] == 1) {
5895                                 btrfs_tree_unlock(eb);
5896                                 path->locks[level] = 0;
5897                                 return 1;
5898                         }
5899                 }
5900         }
5901
5902         /* wc->stage == DROP_REFERENCE */
5903         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
5904
5905         if (wc->refs[level] == 1) {
5906                 if (level == 0) {
5907                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5908                                 ret = btrfs_dec_ref(trans, root, eb, 1);
5909                         else
5910                                 ret = btrfs_dec_ref(trans, root, eb, 0);
5911                         BUG_ON(ret);
5912                 }
5913                 /* make block locked assertion in clean_tree_block happy */
5914                 if (!path->locks[level] &&
5915                     btrfs_header_generation(eb) == trans->transid) {
5916                         btrfs_tree_lock(eb);
5917                         btrfs_set_lock_blocking(eb);
5918                         path->locks[level] = 1;
5919                 }
5920                 clean_tree_block(trans, root, eb);
5921         }
5922
5923         if (eb == root->node) {
5924                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5925                         parent = eb->start;
5926                 else
5927                         BUG_ON(root->root_key.objectid !=
5928                                btrfs_header_owner(eb));
5929         } else {
5930                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5931                         parent = path->nodes[level + 1]->start;
5932                 else
5933                         BUG_ON(root->root_key.objectid !=
5934                                btrfs_header_owner(path->nodes[level + 1]));
5935         }
5936
5937         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
5938 out:
5939         wc->refs[level] = 0;
5940         wc->flags[level] = 0;
5941         return 0;
5942 }
5943
5944 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
5945                                    struct btrfs_root *root,
5946                                    struct btrfs_path *path,
5947                                    struct walk_control *wc)
5948 {
5949         int level = wc->level;
5950         int lookup_info = 1;
5951         int ret;
5952
5953         while (level >= 0) {
5954                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
5955                 if (ret > 0)
5956                         break;
5957
5958                 if (level == 0)
5959                         break;
5960
5961                 if (path->slots[level] >=
5962                     btrfs_header_nritems(path->nodes[level]))
5963                         break;
5964
5965                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
5966                 if (ret > 0) {
5967                         path->slots[level]++;
5968                         continue;
5969                 } else if (ret < 0)
5970                         return ret;
5971                 level = wc->level;
5972         }
5973         return 0;
5974 }
5975
5976 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
5977                                  struct btrfs_root *root,
5978                                  struct btrfs_path *path,
5979                                  struct walk_control *wc, int max_level)
5980 {
5981         int level = wc->level;
5982         int ret;
5983
5984         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
5985         while (level < max_level && path->nodes[level]) {
5986                 wc->level = level;
5987                 if (path->slots[level] + 1 <
5988                     btrfs_header_nritems(path->nodes[level])) {
5989                         path->slots[level]++;
5990                         return 0;
5991                 } else {
5992                         ret = walk_up_proc(trans, root, path, wc);
5993                         if (ret > 0)
5994                                 return 0;
5995
5996                         if (path->locks[level]) {
5997                                 btrfs_tree_unlock(path->nodes[level]);
5998                                 path->locks[level] = 0;
5999                         }
6000                         free_extent_buffer(path->nodes[level]);
6001                         path->nodes[level] = NULL;
6002                         level++;
6003                 }
6004         }
6005         return 1;
6006 }
6007
6008 /*
6009  * drop a subvolume tree.
6010  *
6011  * this function traverses the tree freeing any blocks that only
6012  * referenced by the tree.
6013  *
6014  * when a shared tree block is found. this function decreases its
6015  * reference count by one. if update_ref is true, this function
6016  * also make sure backrefs for the shared block and all lower level
6017  * blocks are properly updated.
6018  */
6019 int btrfs_drop_snapshot(struct btrfs_root *root,
6020                         struct btrfs_block_rsv *block_rsv, int update_ref)
6021 {
6022         struct btrfs_path *path;
6023         struct btrfs_trans_handle *trans;
6024         struct btrfs_root *tree_root = root->fs_info->tree_root;
6025         struct btrfs_root_item *root_item = &root->root_item;
6026         struct walk_control *wc;
6027         struct btrfs_key key;
6028         int err = 0;
6029         int ret;
6030         int level;
6031
6032         path = btrfs_alloc_path();
6033         BUG_ON(!path);
6034
6035         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6036         BUG_ON(!wc);
6037
6038         trans = btrfs_start_transaction(tree_root, 0);
6039         if (block_rsv)
6040                 trans->block_rsv = block_rsv;
6041
6042         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6043                 level = btrfs_header_level(root->node);
6044                 path->nodes[level] = btrfs_lock_root_node(root);
6045                 btrfs_set_lock_blocking(path->nodes[level]);
6046                 path->slots[level] = 0;
6047                 path->locks[level] = 1;
6048                 memset(&wc->update_progress, 0,
6049                        sizeof(wc->update_progress));
6050         } else {
6051                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6052                 memcpy(&wc->update_progress, &key,
6053                        sizeof(wc->update_progress));
6054
6055                 level = root_item->drop_level;
6056                 BUG_ON(level == 0);
6057                 path->lowest_level = level;
6058                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6059                 path->lowest_level = 0;
6060                 if (ret < 0) {
6061                         err = ret;
6062                         goto out;
6063                 }
6064                 WARN_ON(ret > 0);
6065
6066                 /*
6067                  * unlock our path, this is safe because only this
6068                  * function is allowed to delete this snapshot
6069                  */
6070                 btrfs_unlock_up_safe(path, 0);
6071
6072                 level = btrfs_header_level(root->node);
6073                 while (1) {
6074                         btrfs_tree_lock(path->nodes[level]);
6075                         btrfs_set_lock_blocking(path->nodes[level]);
6076
6077                         ret = btrfs_lookup_extent_info(trans, root,
6078                                                 path->nodes[level]->start,
6079                                                 path->nodes[level]->len,
6080                                                 &wc->refs[level],
6081                                                 &wc->flags[level]);
6082                         BUG_ON(ret);
6083                         BUG_ON(wc->refs[level] == 0);
6084
6085                         if (level == root_item->drop_level)
6086                                 break;
6087
6088                         btrfs_tree_unlock(path->nodes[level]);
6089                         WARN_ON(wc->refs[level] != 1);
6090                         level--;
6091                 }
6092         }
6093
6094         wc->level = level;
6095         wc->shared_level = -1;
6096         wc->stage = DROP_REFERENCE;
6097         wc->update_ref = update_ref;
6098         wc->keep_locks = 0;
6099         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6100
6101         while (1) {
6102                 ret = walk_down_tree(trans, root, path, wc);
6103                 if (ret < 0) {
6104                         err = ret;
6105                         break;
6106                 }
6107
6108                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
6109                 if (ret < 0) {
6110                         err = ret;
6111                         break;
6112                 }
6113
6114                 if (ret > 0) {
6115                         BUG_ON(wc->stage != DROP_REFERENCE);
6116                         break;
6117                 }
6118
6119                 if (wc->stage == DROP_REFERENCE) {
6120                         level = wc->level;
6121                         btrfs_node_key(path->nodes[level],
6122                                        &root_item->drop_progress,
6123                                        path->slots[level]);
6124                         root_item->drop_level = level;
6125                 }
6126
6127                 BUG_ON(wc->level == 0);
6128                 if (btrfs_should_end_transaction(trans, tree_root)) {
6129                         ret = btrfs_update_root(trans, tree_root,
6130                                                 &root->root_key,
6131                                                 root_item);
6132                         BUG_ON(ret);
6133
6134                         btrfs_end_transaction_throttle(trans, tree_root);
6135                         trans = btrfs_start_transaction(tree_root, 0);
6136                         if (block_rsv)
6137                                 trans->block_rsv = block_rsv;
6138                 }
6139         }
6140         btrfs_release_path(root, path);
6141         BUG_ON(err);
6142
6143         ret = btrfs_del_root(trans, tree_root, &root->root_key);
6144         BUG_ON(ret);
6145
6146         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
6147                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
6148                                            NULL, NULL);
6149                 BUG_ON(ret < 0);
6150                 if (ret > 0) {
6151                         ret = btrfs_del_orphan_item(trans, tree_root,
6152                                                     root->root_key.objectid);
6153                         BUG_ON(ret);
6154                 }
6155         }
6156
6157         if (root->in_radix) {
6158                 btrfs_free_fs_root(tree_root->fs_info, root);
6159         } else {
6160                 free_extent_buffer(root->node);
6161                 free_extent_buffer(root->commit_root);
6162                 kfree(root);
6163         }
6164 out:
6165         btrfs_end_transaction_throttle(trans, tree_root);
6166         kfree(wc);
6167         btrfs_free_path(path);
6168         return err;
6169 }
6170
6171 /*
6172  * drop subtree rooted at tree block 'node'.
6173  *
6174  * NOTE: this function will unlock and release tree block 'node'
6175  */
6176 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6177                         struct btrfs_root *root,
6178                         struct extent_buffer *node,
6179                         struct extent_buffer *parent)
6180 {
6181         struct btrfs_path *path;
6182         struct walk_control *wc;
6183         int level;
6184         int parent_level;
6185         int ret = 0;
6186         int wret;
6187
6188         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6189
6190         path = btrfs_alloc_path();
6191         BUG_ON(!path);
6192
6193         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6194         BUG_ON(!wc);
6195
6196         btrfs_assert_tree_locked(parent);
6197         parent_level = btrfs_header_level(parent);
6198         extent_buffer_get(parent);
6199         path->nodes[parent_level] = parent;
6200         path->slots[parent_level] = btrfs_header_nritems(parent);
6201
6202         btrfs_assert_tree_locked(node);
6203         level = btrfs_header_level(node);
6204         path->nodes[level] = node;
6205         path->slots[level] = 0;
6206         path->locks[level] = 1;
6207
6208         wc->refs[parent_level] = 1;
6209         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6210         wc->level = level;
6211         wc->shared_level = -1;
6212         wc->stage = DROP_REFERENCE;
6213         wc->update_ref = 0;
6214         wc->keep_locks = 1;
6215         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6216
6217         while (1) {
6218                 wret = walk_down_tree(trans, root, path, wc);
6219                 if (wret < 0) {
6220                         ret = wret;
6221                         break;
6222                 }
6223
6224                 wret = walk_up_tree(trans, root, path, wc, parent_level);
6225                 if (wret < 0)
6226                         ret = wret;
6227                 if (wret != 0)
6228                         break;
6229         }
6230
6231         kfree(wc);
6232         btrfs_free_path(path);
6233         return ret;
6234 }
6235
6236 #if 0
6237 static unsigned long calc_ra(unsigned long start, unsigned long last,
6238                              unsigned long nr)
6239 {
6240         return min(last, start + nr - 1);
6241 }
6242
6243 static noinline int relocate_inode_pages(struct inode *inode, u64 start,
6244                                          u64 len)
6245 {
6246         u64 page_start;
6247         u64 page_end;
6248         unsigned long first_index;
6249         unsigned long last_index;
6250         unsigned long i;
6251         struct page *page;
6252         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
6253         struct file_ra_state *ra;
6254         struct btrfs_ordered_extent *ordered;
6255         unsigned int total_read = 0;
6256         unsigned int total_dirty = 0;
6257         int ret = 0;
6258
6259         ra = kzalloc(sizeof(*ra), GFP_NOFS);
6260
6261         mutex_lock(&inode->i_mutex);
6262         first_index = start >> PAGE_CACHE_SHIFT;
6263         last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
6264
6265         /* make sure the dirty trick played by the caller work */
6266         ret = invalidate_inode_pages2_range(inode->i_mapping,
6267                                             first_index, last_index);
6268         if (ret)
6269                 goto out_unlock;
6270
6271         file_ra_state_init(ra, inode->i_mapping);
6272
6273         for (i = first_index ; i <= last_index; i++) {
6274                 if (total_read % ra->ra_pages == 0) {
6275                         btrfs_force_ra(inode->i_mapping, ra, NULL, i,
6276                                        calc_ra(i, last_index, ra->ra_pages));
6277                 }
6278                 total_read++;
6279 again:
6280                 if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
6281                         BUG_ON(1);
6282                 page = grab_cache_page(inode->i_mapping, i);
6283                 if (!page) {
6284                         ret = -ENOMEM;
6285                         goto out_unlock;
6286                 }
6287                 if (!PageUptodate(page)) {
6288                         btrfs_readpage(NULL, page);
6289                         lock_page(page);
6290                         if (!PageUptodate(page)) {
6291                                 unlock_page(page);
6292                                 page_cache_release(page);
6293                                 ret = -EIO;
6294                                 goto out_unlock;
6295                         }
6296                 }
6297                 wait_on_page_writeback(page);
6298
6299                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
6300                 page_end = page_start + PAGE_CACHE_SIZE - 1;
6301                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
6302
6303                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
6304                 if (ordered) {
6305                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
6306                         unlock_page(page);
6307                         page_cache_release(page);
6308                         btrfs_start_ordered_extent(inode, ordered, 1);
6309                         btrfs_put_ordered_extent(ordered);
6310                         goto again;
6311                 }
6312                 set_page_extent_mapped(page);
6313
6314                 if (i == first_index)
6315                         set_extent_bits(io_tree, page_start, page_end,
6316                                         EXTENT_BOUNDARY, GFP_NOFS);
6317                 btrfs_set_extent_delalloc(inode, page_start, page_end);
6318
6319                 set_page_dirty(page);
6320                 total_dirty++;
6321
6322                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
6323                 unlock_page(page);
6324                 page_cache_release(page);
6325         }
6326
6327 out_unlock:
6328         kfree(ra);
6329         mutex_unlock(&inode->i_mutex);
6330         balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
6331         return ret;
6332 }
6333
6334 static noinline int relocate_data_extent(struct inode *reloc_inode,
6335                                          struct btrfs_key *extent_key,
6336                                          u64 offset)
6337 {
6338         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
6339         struct extent_map_tree *em_tree = &BTRFS_I(reloc_inode)->extent_tree;
6340         struct extent_map *em;
6341         u64 start = extent_key->objectid - offset;
6342         u64 end = start + extent_key->offset - 1;
6343
6344         em = alloc_extent_map(GFP_NOFS);
6345         BUG_ON(!em || IS_ERR(em));
6346
6347         em->start = start;
6348         em->len = extent_key->offset;
6349         em->block_len = extent_key->offset;
6350         em->block_start = extent_key->objectid;
6351         em->bdev = root->fs_info->fs_devices->latest_bdev;
6352         set_bit(EXTENT_FLAG_PINNED, &em->flags);
6353
6354         /* setup extent map to cheat btrfs_readpage */
6355         lock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
6356         while (1) {
6357                 int ret;
6358                 write_lock(&em_tree->lock);
6359                 ret = add_extent_mapping(em_tree, em);
6360                 write_unlock(&em_tree->lock);
6361                 if (ret != -EEXIST) {
6362                         free_extent_map(em);
6363                         break;
6364                 }
6365                 btrfs_drop_extent_cache(reloc_inode, start, end, 0);
6366         }
6367         unlock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
6368
6369         return relocate_inode_pages(reloc_inode, start, extent_key->offset);
6370 }
6371
6372 struct btrfs_ref_path {
6373         u64 extent_start;
6374         u64 nodes[BTRFS_MAX_LEVEL];
6375         u64 root_objectid;
6376         u64 root_generation;
6377         u64 owner_objectid;
6378         u32 num_refs;
6379         int lowest_level;
6380         int current_level;
6381         int shared_level;
6382
6383         struct btrfs_key node_keys[BTRFS_MAX_LEVEL];
6384         u64 new_nodes[BTRFS_MAX_LEVEL];
6385 };
6386
6387 struct disk_extent {
6388         u64 ram_bytes;
6389         u64 disk_bytenr;
6390         u64 disk_num_bytes;
6391         u64 offset;
6392         u64 num_bytes;
6393         u8 compression;
6394         u8 encryption;
6395         u16 other_encoding;
6396 };
6397
6398 static int is_cowonly_root(u64 root_objectid)
6399 {
6400         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
6401             root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
6402             root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
6403             root_objectid == BTRFS_DEV_TREE_OBJECTID ||
6404             root_objectid == BTRFS_TREE_LOG_OBJECTID ||
6405             root_objectid == BTRFS_CSUM_TREE_OBJECTID)
6406                 return 1;
6407         return 0;
6408 }
6409
6410 static noinline int __next_ref_path(struct btrfs_trans_handle *trans,
6411                                     struct btrfs_root *extent_root,
6412                                     struct btrfs_ref_path *ref_path,
6413                                     int first_time)
6414 {
6415         struct extent_buffer *leaf;
6416         struct btrfs_path *path;
6417         struct btrfs_extent_ref *ref;
6418         struct btrfs_key key;
6419         struct btrfs_key found_key;
6420         u64 bytenr;
6421         u32 nritems;
6422         int level;
6423         int ret = 1;
6424
6425         path = btrfs_alloc_path();
6426         if (!path)
6427                 return -ENOMEM;
6428
6429         if (first_time) {
6430                 ref_path->lowest_level = -1;
6431                 ref_path->current_level = -1;
6432                 ref_path->shared_level = -1;
6433                 goto walk_up;
6434         }
6435 walk_down:
6436         level = ref_path->current_level - 1;
6437         while (level >= -1) {
6438                 u64 parent;
6439                 if (level < ref_path->lowest_level)
6440                         break;
6441
6442                 if (level >= 0)
6443                         bytenr = ref_path->nodes[level];
6444                 else
6445                         bytenr = ref_path->extent_start;
6446                 BUG_ON(bytenr == 0);
6447
6448                 parent = ref_path->nodes[level + 1];
6449                 ref_path->nodes[level + 1] = 0;
6450                 ref_path->current_level = level;
6451                 BUG_ON(parent == 0);
6452
6453                 key.objectid = bytenr;
6454                 key.offset = parent + 1;
6455                 key.type = BTRFS_EXTENT_REF_KEY;
6456
6457                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
6458                 if (ret < 0)
6459                         goto out;
6460                 BUG_ON(ret == 0);
6461
6462                 leaf = path->nodes[0];
6463                 nritems = btrfs_header_nritems(leaf);
6464                 if (path->slots[0] >= nritems) {
6465                         ret = btrfs_next_leaf(extent_root, path);
6466                         if (ret < 0)
6467                                 goto out;
6468                         if (ret > 0)
6469                                 goto next;
6470                         leaf = path->nodes[0];
6471                 }
6472
6473                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6474                 if (found_key.objectid == bytenr &&
6475                     found_key.type == BTRFS_EXTENT_REF_KEY) {
6476                         if (level < ref_path->shared_level)
6477                                 ref_path->shared_level = level;
6478                         goto found;
6479                 }
6480 next:
6481                 level--;
6482                 btrfs_release_path(extent_root, path);
6483                 cond_resched();
6484         }
6485         /* reached lowest level */
6486         ret = 1;
6487         goto out;
6488 walk_up:
6489         level = ref_path->current_level;
6490         while (level < BTRFS_MAX_LEVEL - 1) {
6491                 u64 ref_objectid;
6492
6493                 if (level >= 0)
6494                         bytenr = ref_path->nodes[level];
6495                 else
6496                         bytenr = ref_path->extent_start;
6497
6498                 BUG_ON(bytenr == 0);
6499
6500                 key.objectid = bytenr;
6501                 key.offset = 0;
6502                 key.type = BTRFS_EXTENT_REF_KEY;
6503
6504                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
6505                 if (ret < 0)
6506                         goto out;
6507
6508                 leaf = path->nodes[0];
6509                 nritems = btrfs_header_nritems(leaf);
6510                 if (path->slots[0] >= nritems) {
6511                         ret = btrfs_next_leaf(extent_root, path);
6512                         if (ret < 0)
6513                                 goto out;
6514                         if (ret > 0) {
6515                                 /* the extent was freed by someone */
6516                                 if (ref_path->lowest_level == level)
6517                                         goto out;
6518                                 btrfs_release_path(extent_root, path);
6519                                 goto walk_down;
6520                         }
6521                         leaf = path->nodes[0];
6522                 }
6523
6524                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6525                 if (found_key.objectid != bytenr ||
6526                                 found_key.type != BTRFS_EXTENT_REF_KEY) {
6527                         /* the extent was freed by someone */
6528                         if (ref_path->lowest_level == level) {
6529                                 ret = 1;
6530                                 goto out;
6531                         }
6532                         btrfs_release_path(extent_root, path);
6533                         goto walk_down;
6534                 }
6535 found:
6536                 ref = btrfs_item_ptr(leaf, path->slots[0],
6537                                 struct btrfs_extent_ref);
6538                 ref_objectid = btrfs_ref_objectid(leaf, ref);
6539                 if (ref_objectid < BTRFS_FIRST_FREE_OBJECTID) {
6540                         if (first_time) {
6541                                 level = (int)ref_objectid;
6542                                 BUG_ON(level >= BTRFS_MAX_LEVEL);
6543                                 ref_path->lowest_level = level;
6544                                 ref_path->current_level = level;
6545                                 ref_path->nodes[level] = bytenr;
6546                         } else {
6547                                 WARN_ON(ref_objectid != level);
6548                         }
6549                 } else {
6550                         WARN_ON(level != -1);
6551                 }
6552                 first_time = 0;
6553
6554                 if (ref_path->lowest_level == level) {
6555                         ref_path->owner_objectid = ref_objectid;
6556                         ref_path->num_refs = btrfs_ref_num_refs(leaf, ref);
6557                 }
6558
6559                 /*
6560                  * the block is tree root or the block isn't in reference
6561                  * counted tree.
6562                  */
6563                 if (found_key.objectid == found_key.offset ||
6564                     is_cowonly_root(btrfs_ref_root(leaf, ref))) {
6565                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
6566                         ref_path->root_generation =
6567                                 btrfs_ref_generation(leaf, ref);
6568                         if (level < 0) {
6569                                 /* special reference from the tree log */
6570                                 ref_path->nodes[0] = found_key.offset;
6571                                 ref_path->current_level = 0;
6572                         }
6573                         ret = 0;
6574                         goto out;
6575                 }
6576
6577                 level++;
6578                 BUG_ON(ref_path->nodes[level] != 0);
6579                 ref_path->nodes[level] = found_key.offset;
6580                 ref_path->current_level = level;
6581
6582                 /*
6583                  * the reference was created in the running transaction,
6584                  * no need to continue walking up.
6585                  */
6586                 if (btrfs_ref_generation(leaf, ref) == trans->transid) {
6587                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
6588                         ref_path->root_generation =
6589                                 btrfs_ref_generation(leaf, ref);
6590                         ret = 0;
6591                         goto out;
6592                 }
6593
6594                 btrfs_release_path(extent_root, path);
6595                 cond_resched();
6596         }
6597         /* reached max tree level, but no tree root found. */
6598         BUG();
6599 out:
6600         btrfs_free_path(path);
6601         return ret;
6602 }
6603
6604 static int btrfs_first_ref_path(struct btrfs_trans_handle *trans,
6605                                 struct btrfs_root *extent_root,
6606                                 struct btrfs_ref_path *ref_path,
6607                                 u64 extent_start)
6608 {
6609         memset(ref_path, 0, sizeof(*ref_path));
6610         ref_path->extent_start = extent_start;
6611
6612         return __next_ref_path(trans, extent_root, ref_path, 1);
6613 }
6614
6615 static int btrfs_next_ref_path(struct btrfs_trans_handle *trans,
6616                                struct btrfs_root *extent_root,
6617                                struct btrfs_ref_path *ref_path)
6618 {
6619         return __next_ref_path(trans, extent_root, ref_path, 0);
6620 }
6621
6622 static noinline int get_new_locations(struct inode *reloc_inode,
6623                                       struct btrfs_key *extent_key,
6624                                       u64 offset, int no_fragment,
6625                                       struct disk_extent **extents,
6626                                       int *nr_extents)
6627 {
6628         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
6629         struct btrfs_path *path;
6630         struct btrfs_file_extent_item *fi;
6631         struct extent_buffer *leaf;
6632         struct disk_extent *exts = *extents;
6633         struct btrfs_key found_key;
6634         u64 cur_pos;
6635         u64 last_byte;
6636         u32 nritems;
6637         int nr = 0;
6638         int max = *nr_extents;
6639         int ret;
6640
6641         WARN_ON(!no_fragment && *extents);
6642         if (!exts) {
6643                 max = 1;
6644                 exts = kmalloc(sizeof(*exts) * max, GFP_NOFS);
6645                 if (!exts)
6646                         return -ENOMEM;
6647         }
6648
6649         path = btrfs_alloc_path();
6650         BUG_ON(!path);
6651
6652         cur_pos = extent_key->objectid - offset;
6653         last_byte = extent_key->objectid + extent_key->offset;
6654         ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
6655                                        cur_pos, 0);
6656         if (ret < 0)
6657                 goto out;
6658         if (ret > 0) {
6659                 ret = -ENOENT;
6660                 goto out;
6661         }
6662
6663         while (1) {
6664                 leaf = path->nodes[0];
6665                 nritems = btrfs_header_nritems(leaf);
6666                 if (path->slots[0] >= nritems) {
6667                         ret = btrfs_next_leaf(root, path);
6668                         if (ret < 0)
6669                                 goto out;
6670                         if (ret > 0)
6671                                 break;
6672                         leaf = path->nodes[0];
6673                 }
6674
6675                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6676                 if (found_key.offset != cur_pos ||
6677                     found_key.type != BTRFS_EXTENT_DATA_KEY ||
6678                     found_key.objectid != reloc_inode->i_ino)
6679                         break;
6680
6681                 fi = btrfs_item_ptr(leaf, path->slots[0],
6682                                     struct btrfs_file_extent_item);
6683                 if (btrfs_file_extent_type(leaf, fi) !=
6684                     BTRFS_FILE_EXTENT_REG ||
6685                     btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
6686                         break;
6687
6688                 if (nr == max) {
6689                         struct disk_extent *old = exts;
6690                         max *= 2;
6691                         exts = kzalloc(sizeof(*exts) * max, GFP_NOFS);
6692                         memcpy(exts, old, sizeof(*exts) * nr);
6693                         if (old != *extents)
6694                                 kfree(old);
6695                 }
6696
6697                 exts[nr].disk_bytenr =
6698                         btrfs_file_extent_disk_bytenr(leaf, fi);
6699                 exts[nr].disk_num_bytes =
6700                         btrfs_file_extent_disk_num_bytes(leaf, fi);
6701                 exts[nr].offset = btrfs_file_extent_offset(leaf, fi);
6702                 exts[nr].num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
6703                 exts[nr].ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
6704                 exts[nr].compression = btrfs_file_extent_compression(leaf, fi);
6705                 exts[nr].encryption = btrfs_file_extent_encryption(leaf, fi);
6706                 exts[nr].other_encoding = btrfs_file_extent_other_encoding(leaf,
6707                                                                            fi);
6708                 BUG_ON(exts[nr].offset > 0);
6709                 BUG_ON(exts[nr].compression || exts[nr].encryption);
6710                 BUG_ON(exts[nr].num_bytes != exts[nr].disk_num_bytes);
6711
6712                 cur_pos += exts[nr].num_bytes;
6713                 nr++;
6714
6715                 if (cur_pos + offset >= last_byte)
6716                         break;
6717
6718                 if (no_fragment) {
6719                         ret = 1;
6720                         goto out;
6721                 }
6722                 path->slots[0]++;
6723         }
6724
6725         BUG_ON(cur_pos + offset > last_byte);
6726         if (cur_pos + offset < last_byte) {
6727                 ret = -ENOENT;
6728                 goto out;
6729         }
6730         ret = 0;
6731 out:
6732         btrfs_free_path(path);
6733         if (ret) {
6734                 if (exts != *extents)
6735                         kfree(exts);
6736         } else {
6737                 *extents = exts;
6738                 *nr_extents = nr;
6739         }
6740         return ret;
6741 }
6742
6743 static noinline int replace_one_extent(struct btrfs_trans_handle *trans,
6744                                         struct btrfs_root *root,
6745                                         struct btrfs_path *path,
6746                                         struct btrfs_key *extent_key,
6747                                         struct btrfs_key *leaf_key,
6748                                         struct btrfs_ref_path *ref_path,
6749                                         struct disk_extent *new_extents,
6750                                         int nr_extents)
6751 {
6752         struct extent_buffer *leaf;
6753         struct btrfs_file_extent_item *fi;
6754         struct inode *inode = NULL;
6755         struct btrfs_key key;
6756         u64 lock_start = 0;
6757         u64 lock_end = 0;
6758         u64 num_bytes;
6759         u64 ext_offset;
6760         u64 search_end = (u64)-1;
6761         u32 nritems;
6762         int nr_scaned = 0;
6763         int extent_locked = 0;
6764         int extent_type;
6765         int ret;
6766
6767         memcpy(&key, leaf_key, sizeof(key));
6768         if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
6769                 if (key.objectid < ref_path->owner_objectid ||
6770                     (key.objectid == ref_path->owner_objectid &&
6771                      key.type < BTRFS_EXTENT_DATA_KEY)) {
6772                         key.objectid = ref_path->owner_objectid;
6773                         key.type = BTRFS_EXTENT_DATA_KEY;
6774                         key.offset = 0;
6775                 }
6776         }
6777
6778         while (1) {
6779                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
6780                 if (ret < 0)
6781                         goto out;
6782
6783                 leaf = path->nodes[0];
6784                 nritems = btrfs_header_nritems(leaf);
6785 next:
6786                 if (extent_locked && ret > 0) {
6787                         /*
6788                          * the file extent item was modified by someone
6789                          * before the extent got locked.
6790                          */
6791                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
6792                                       lock_end, GFP_NOFS);
6793                         extent_locked = 0;
6794                 }
6795
6796                 if (path->slots[0] >= nritems) {
6797                         if (++nr_scaned > 2)
6798                                 break;
6799
6800                         BUG_ON(extent_locked);
6801                         ret = btrfs_next_leaf(root, path);
6802                         if (ret < 0)
6803                                 goto out;
6804                         if (ret > 0)
6805                                 break;
6806                         leaf = path->nodes[0];
6807                         nritems = btrfs_header_nritems(leaf);
6808                 }
6809
6810                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
6811
6812                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
6813                         if ((key.objectid > ref_path->owner_objectid) ||
6814                             (key.objectid == ref_path->owner_objectid &&
6815                              key.type > BTRFS_EXTENT_DATA_KEY) ||
6816                             key.offset >= search_end)
6817                                 break;
6818                 }
6819
6820                 if (inode && key.objectid != inode->i_ino) {
6821                         BUG_ON(extent_locked);
6822                         btrfs_release_path(root, path);
6823                         mutex_unlock(&inode->i_mutex);
6824                         iput(inode);
6825                         inode = NULL;
6826                         continue;
6827                 }
6828
6829                 if (key.type != BTRFS_EXTENT_DATA_KEY) {
6830                         path->slots[0]++;
6831                         ret = 1;
6832                         goto next;
6833                 }
6834                 fi = btrfs_item_ptr(leaf, path->slots[0],
6835                                     struct btrfs_file_extent_item);
6836                 extent_type = btrfs_file_extent_type(leaf, fi);
6837                 if ((extent_type != BTRFS_FILE_EXTENT_REG &&
6838                      extent_type != BTRFS_FILE_EXTENT_PREALLOC) ||
6839                     (btrfs_file_extent_disk_bytenr(leaf, fi) !=
6840                      extent_key->objectid)) {
6841                         path->slots[0]++;
6842                         ret = 1;
6843                         goto next;
6844                 }
6845
6846                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
6847                 ext_offset = btrfs_file_extent_offset(leaf, fi);
6848
6849                 if (search_end == (u64)-1) {
6850                         search_end = key.offset - ext_offset +
6851                                 btrfs_file_extent_ram_bytes(leaf, fi);
6852                 }
6853
6854                 if (!extent_locked) {
6855                         lock_start = key.offset;
6856                         lock_end = lock_start + num_bytes - 1;
6857                 } else {
6858                         if (lock_start > key.offset ||
6859                             lock_end + 1 < key.offset + num_bytes) {
6860                                 unlock_extent(&BTRFS_I(inode)->io_tree,
6861                                               lock_start, lock_end, GFP_NOFS);
6862                                 extent_locked = 0;
6863                         }
6864                 }
6865
6866                 if (!inode) {
6867                         btrfs_release_path(root, path);
6868
6869                         inode = btrfs_iget_locked(root->fs_info->sb,
6870                                                   key.objectid, root);
6871                         if (inode->i_state & I_NEW) {
6872                                 BTRFS_I(inode)->root = root;
6873                                 BTRFS_I(inode)->location.objectid =
6874                                         key.objectid;
6875                                 BTRFS_I(inode)->location.type =
6876                                         BTRFS_INODE_ITEM_KEY;
6877                                 BTRFS_I(inode)->location.offset = 0;
6878                                 btrfs_read_locked_inode(inode);
6879                                 unlock_new_inode(inode);
6880                         }
6881                         /*
6882                          * some code call btrfs_commit_transaction while
6883                          * holding the i_mutex, so we can't use mutex_lock
6884                          * here.
6885                          */
6886                         if (is_bad_inode(inode) ||
6887                             !mutex_trylock(&inode->i_mutex)) {
6888                                 iput(inode);
6889                                 inode = NULL;
6890                                 key.offset = (u64)-1;
6891                                 goto skip;
6892                         }
6893                 }
6894
6895                 if (!extent_locked) {
6896                         struct btrfs_ordered_extent *ordered;
6897
6898                         btrfs_release_path(root, path);
6899
6900                         lock_extent(&BTRFS_I(inode)->io_tree, lock_start,
6901                                     lock_end, GFP_NOFS);
6902                         ordered = btrfs_lookup_first_ordered_extent(inode,
6903                                                                     lock_end);
6904                         if (ordered &&
6905                             ordered->file_offset <= lock_end &&
6906                             ordered->file_offset + ordered->len > lock_start) {
6907                                 unlock_extent(&BTRFS_I(inode)->io_tree,
6908                                               lock_start, lock_end, GFP_NOFS);
6909                                 btrfs_start_ordered_extent(inode, ordered, 1);
6910                                 btrfs_put_ordered_extent(ordered);
6911                                 key.offset += num_bytes;
6912                                 goto skip;
6913                         }
6914                         if (ordered)
6915                                 btrfs_put_ordered_extent(ordered);
6916
6917                         extent_locked = 1;
6918                         continue;
6919                 }
6920
6921                 if (nr_extents == 1) {
6922                         /* update extent pointer in place */
6923                         btrfs_set_file_extent_disk_bytenr(leaf, fi,
6924                                                 new_extents[0].disk_bytenr);
6925                         btrfs_set_file_extent_disk_num_bytes(leaf, fi,
6926                                                 new_extents[0].disk_num_bytes);
6927                         btrfs_mark_buffer_dirty(leaf);
6928
6929                         btrfs_drop_extent_cache(inode, key.offset,
6930                                                 key.offset + num_bytes - 1, 0);
6931
6932                         ret = btrfs_inc_extent_ref(trans, root,
6933                                                 new_extents[0].disk_bytenr,
6934                                                 new_extents[0].disk_num_bytes,
6935                                                 leaf->start,
6936                                                 root->root_key.objectid,
6937                                                 trans->transid,
6938                                                 key.objectid);
6939                         BUG_ON(ret);
6940
6941                         ret = btrfs_free_extent(trans, root,
6942                                                 extent_key->objectid,
6943                                                 extent_key->offset,
6944                                                 leaf->start,
6945                                                 btrfs_header_owner(leaf),
6946                                                 btrfs_header_generation(leaf),
6947                                                 key.objectid, 0);
6948                         BUG_ON(ret);
6949
6950                         btrfs_release_path(root, path);
6951                         key.offset += num_bytes;
6952                 } else {
6953                         BUG_ON(1);
6954 #if 0
6955                         u64 alloc_hint;
6956                         u64 extent_len;
6957                         int i;
6958                         /*
6959                          * drop old extent pointer at first, then insert the
6960                          * new pointers one bye one
6961                          */
6962                         btrfs_release_path(root, path);
6963                         ret = btrfs_drop_extents(trans, root, inode, key.offset,
6964                                                  key.offset + num_bytes,
6965                                                  key.offset, &alloc_hint);
6966                         BUG_ON(ret);
6967
6968                         for (i = 0; i < nr_extents; i++) {
6969                                 if (ext_offset >= new_extents[i].num_bytes) {
6970                                         ext_offset -= new_extents[i].num_bytes;
6971                                         continue;
6972                                 }
6973                                 extent_len = min(new_extents[i].num_bytes -
6974                                                  ext_offset, num_bytes);
6975
6976                                 ret = btrfs_insert_empty_item(trans, root,
6977                                                               path, &key,
6978                                                               sizeof(*fi));
6979                                 BUG_ON(ret);
6980
6981                                 leaf = path->nodes[0];
6982                                 fi = btrfs_item_ptr(leaf, path->slots[0],
6983                                                 struct btrfs_file_extent_item);
6984                                 btrfs_set_file_extent_generation(leaf, fi,
6985                                                         trans->transid);
6986                                 btrfs_set_file_extent_type(leaf, fi,
6987                                                         BTRFS_FILE_EXTENT_REG);
6988                                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
6989                                                 new_extents[i].disk_bytenr);
6990                                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
6991                                                 new_extents[i].disk_num_bytes);
6992                                 btrfs_set_file_extent_ram_bytes(leaf, fi,
6993                                                 new_extents[i].ram_bytes);
6994
6995                                 btrfs_set_file_extent_compression(leaf, fi,
6996                                                 new_extents[i].compression);
6997                                 btrfs_set_file_extent_encryption(leaf, fi,
6998                                                 new_extents[i].encryption);
6999                                 btrfs_set_file_extent_other_encoding(leaf, fi,
7000                                                 new_extents[i].other_encoding);
7001
7002                                 btrfs_set_file_extent_num_bytes(leaf, fi,
7003                                                         extent_len);
7004                                 ext_offset += new_extents[i].offset;
7005                                 btrfs_set_file_extent_offset(leaf, fi,
7006                                                         ext_offset);
7007                                 btrfs_mark_buffer_dirty(leaf);
7008
7009                                 btrfs_drop_extent_cache(inode, key.offset,
7010                                                 key.offset + extent_len - 1, 0);
7011
7012                                 ret = btrfs_inc_extent_ref(trans, root,
7013                                                 new_extents[i].disk_bytenr,
7014                                                 new_extents[i].disk_num_bytes,
7015                                                 leaf->start,
7016                                                 root->root_key.objectid,
7017                                                 trans->transid, key.objectid);
7018                                 BUG_ON(ret);
7019                                 btrfs_release_path(root, path);
7020
7021                                 inode_add_bytes(inode, extent_len);
7022
7023                                 ext_offset = 0;
7024                                 num_bytes -= extent_len;
7025                                 key.offset += extent_len;
7026
7027                                 if (num_bytes == 0)
7028                                         break;
7029                         }
7030                         BUG_ON(i >= nr_extents);
7031 #endif
7032                 }
7033
7034                 if (extent_locked) {
7035                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
7036                                       lock_end, GFP_NOFS);
7037                         extent_locked = 0;
7038                 }
7039 skip:
7040                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS &&
7041                     key.offset >= search_end)
7042                         break;
7043
7044                 cond_resched();
7045         }
7046         ret = 0;
7047 out:
7048         btrfs_release_path(root, path);
7049         if (inode) {
7050                 mutex_unlock(&inode->i_mutex);
7051                 if (extent_locked) {
7052                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
7053                                       lock_end, GFP_NOFS);
7054                 }
7055                 iput(inode);
7056         }
7057         return ret;
7058 }
7059
7060 int btrfs_reloc_tree_cache_ref(struct btrfs_trans_handle *trans,
7061                                struct btrfs_root *root,
7062                                struct extent_buffer *buf, u64 orig_start)
7063 {
7064         int level;
7065         int ret;
7066
7067         BUG_ON(btrfs_header_generation(buf) != trans->transid);
7068         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7069
7070         level = btrfs_header_level(buf);
7071         if (level == 0) {
7072                 struct btrfs_leaf_ref *ref;
7073                 struct btrfs_leaf_ref *orig_ref;
7074
7075                 orig_ref = btrfs_lookup_leaf_ref(root, orig_start);
7076                 if (!orig_ref)
7077                         return -ENOENT;
7078
7079                 ref = btrfs_alloc_leaf_ref(root, orig_ref->nritems);
7080                 if (!ref) {
7081                         btrfs_free_leaf_ref(root, orig_ref);
7082                         return -ENOMEM;
7083                 }
7084
7085                 ref->nritems = orig_ref->nritems;
7086                 memcpy(ref->extents, orig_ref->extents,
7087                         sizeof(ref->extents[0]) * ref->nritems);
7088
7089                 btrfs_free_leaf_ref(root, orig_ref);
7090
7091                 ref->root_gen = trans->transid;
7092                 ref->bytenr = buf->start;
7093                 ref->owner = btrfs_header_owner(buf);
7094                 ref->generation = btrfs_header_generation(buf);
7095
7096                 ret = btrfs_add_leaf_ref(root, ref, 0);
7097                 WARN_ON(ret);
7098                 btrfs_free_leaf_ref(root, ref);
7099         }
7100         return 0;
7101 }
7102
7103 static noinline int invalidate_extent_cache(struct btrfs_root *root,
7104                                         struct extent_buffer *leaf,
7105                                         struct btrfs_block_group_cache *group,
7106                                         struct btrfs_root *target_root)
7107 {
7108         struct btrfs_key key;
7109         struct inode *inode = NULL;
7110         struct btrfs_file_extent_item *fi;
7111         struct extent_state *cached_state = NULL;
7112         u64 num_bytes;
7113         u64 skip_objectid = 0;
7114         u32 nritems;
7115         u32 i;
7116
7117         nritems = btrfs_header_nritems(leaf);
7118         for (i = 0; i < nritems; i++) {
7119                 btrfs_item_key_to_cpu(leaf, &key, i);
7120                 if (key.objectid == skip_objectid ||
7121                     key.type != BTRFS_EXTENT_DATA_KEY)
7122                         continue;
7123                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
7124                 if (btrfs_file_extent_type(leaf, fi) ==
7125                     BTRFS_FILE_EXTENT_INLINE)
7126                         continue;
7127                 if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
7128                         continue;
7129                 if (!inode || inode->i_ino != key.objectid) {
7130                         iput(inode);
7131                         inode = btrfs_ilookup(target_root->fs_info->sb,
7132                                               key.objectid, target_root, 1);
7133                 }
7134                 if (!inode) {
7135                         skip_objectid = key.objectid;
7136                         continue;
7137                 }
7138                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
7139
7140                 lock_extent_bits(&BTRFS_I(inode)->io_tree, key.offset,
7141                                  key.offset + num_bytes - 1, 0, &cached_state,
7142                                  GFP_NOFS);
7143                 btrfs_drop_extent_cache(inode, key.offset,
7144                                         key.offset + num_bytes - 1, 1);
7145                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, key.offset,
7146                                      key.offset + num_bytes - 1, &cached_state,
7147                                      GFP_NOFS);
7148                 cond_resched();
7149         }
7150         iput(inode);
7151         return 0;
7152 }
7153
7154 static noinline int replace_extents_in_leaf(struct btrfs_trans_handle *trans,
7155                                         struct btrfs_root *root,
7156                                         struct extent_buffer *leaf,
7157                                         struct btrfs_block_group_cache *group,
7158                                         struct inode *reloc_inode)
7159 {
7160         struct btrfs_key key;
7161         struct btrfs_key extent_key;
7162         struct btrfs_file_extent_item *fi;
7163         struct btrfs_leaf_ref *ref;
7164         struct disk_extent *new_extent;
7165         u64 bytenr;
7166         u64 num_bytes;
7167         u32 nritems;
7168         u32 i;
7169         int ext_index;
7170         int nr_extent;
7171         int ret;
7172
7173         new_extent = kmalloc(sizeof(*new_extent), GFP_NOFS);
7174         BUG_ON(!new_extent);
7175
7176         ref = btrfs_lookup_leaf_ref(root, leaf->start);
7177         BUG_ON(!ref);
7178
7179         ext_index = -1;
7180         nritems = btrfs_header_nritems(leaf);
7181         for (i = 0; i < nritems; i++) {
7182                 btrfs_item_key_to_cpu(leaf, &key, i);
7183                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
7184                         continue;
7185                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
7186                 if (btrfs_file_extent_type(leaf, fi) ==
7187                     BTRFS_FILE_EXTENT_INLINE)
7188                         continue;
7189                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
7190                 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
7191                 if (bytenr == 0)
7192                         continue;
7193
7194                 ext_index++;
7195                 if (bytenr >= group->key.objectid + group->key.offset ||
7196                     bytenr + num_bytes <= group->key.objectid)
7197                         continue;
7198
7199                 extent_key.objectid = bytenr;
7200                 extent_key.offset = num_bytes;
7201                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
7202                 nr_extent = 1;
7203                 ret = get_new_locations(reloc_inode, &extent_key,
7204                                         group->key.objectid, 1,
7205                                         &new_extent, &nr_extent);
7206                 if (ret > 0)
7207                         continue;
7208                 BUG_ON(ret < 0);
7209
7210                 BUG_ON(ref->extents[ext_index].bytenr != bytenr);
7211                 BUG_ON(ref->extents[ext_index].num_bytes != num_bytes);
7212                 ref->extents[ext_index].bytenr = new_extent->disk_bytenr;
7213                 ref->extents[ext_index].num_bytes = new_extent->disk_num_bytes;
7214
7215                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
7216                                                 new_extent->disk_bytenr);
7217                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
7218                                                 new_extent->disk_num_bytes);
7219                 btrfs_mark_buffer_dirty(leaf);
7220
7221                 ret = btrfs_inc_extent_ref(trans, root,
7222                                         new_extent->disk_bytenr,
7223                                         new_extent->disk_num_bytes,
7224                                         leaf->start,
7225                                         root->root_key.objectid,
7226                                         trans->transid, key.objectid);
7227                 BUG_ON(ret);
7228
7229                 ret = btrfs_free_extent(trans, root,
7230                                         bytenr, num_bytes, leaf->start,
7231                                         btrfs_header_owner(leaf),
7232                                         btrfs_header_generation(leaf),
7233                                         key.objectid, 0);
7234                 BUG_ON(ret);
7235                 cond_resched();
7236         }
7237         kfree(new_extent);
7238         BUG_ON(ext_index + 1 != ref->nritems);
7239         btrfs_free_leaf_ref(root, ref);
7240         return 0;
7241 }
7242
7243 int btrfs_free_reloc_root(struct btrfs_trans_handle *trans,
7244                           struct btrfs_root *root)
7245 {
7246         struct btrfs_root *reloc_root;
7247         int ret;
7248
7249         if (root->reloc_root) {
7250                 reloc_root = root->reloc_root;
7251                 root->reloc_root = NULL;
7252                 list_add(&reloc_root->dead_list,
7253                          &root->fs_info->dead_reloc_roots);
7254
7255                 btrfs_set_root_bytenr(&reloc_root->root_item,
7256                                       reloc_root->node->start);
7257                 btrfs_set_root_level(&root->root_item,
7258                                      btrfs_header_level(reloc_root->node));
7259                 memset(&reloc_root->root_item.drop_progress, 0,
7260                         sizeof(struct btrfs_disk_key));
7261                 reloc_root->root_item.drop_level = 0;
7262
7263                 ret = btrfs_update_root(trans, root->fs_info->tree_root,
7264                                         &reloc_root->root_key,
7265                                         &reloc_root->root_item);
7266                 BUG_ON(ret);
7267         }
7268         return 0;
7269 }
7270
7271 int btrfs_drop_dead_reloc_roots(struct btrfs_root *root)
7272 {
7273         struct btrfs_trans_handle *trans;
7274         struct btrfs_root *reloc_root;
7275         struct btrfs_root *prev_root = NULL;
7276         struct list_head dead_roots;
7277         int ret;
7278         unsigned long nr;
7279
7280         INIT_LIST_HEAD(&dead_roots);
7281         list_splice_init(&root->fs_info->dead_reloc_roots, &dead_roots);
7282
7283         while (!list_empty(&dead_roots)) {
7284                 reloc_root = list_entry(dead_roots.prev,
7285                                         struct btrfs_root, dead_list);
7286                 list_del_init(&reloc_root->dead_list);
7287
7288                 BUG_ON(reloc_root->commit_root != NULL);
7289                 while (1) {
7290                         trans = btrfs_join_transaction(root, 1);
7291                         BUG_ON(!trans);
7292
7293                         mutex_lock(&root->fs_info->drop_mutex);
7294                         ret = btrfs_drop_snapshot(trans, reloc_root);
7295                         if (ret != -EAGAIN)
7296                                 break;
7297                         mutex_unlock(&root->fs_info->drop_mutex);
7298
7299                         nr = trans->blocks_used;
7300                         ret = btrfs_end_transaction(trans, root);
7301                         BUG_ON(ret);
7302                         btrfs_btree_balance_dirty(root, nr);
7303                 }
7304
7305                 free_extent_buffer(reloc_root->node);
7306
7307                 ret = btrfs_del_root(trans, root->fs_info->tree_root,
7308                                      &reloc_root->root_key);
7309                 BUG_ON(ret);
7310                 mutex_unlock(&root->fs_info->drop_mutex);
7311
7312                 nr = trans->blocks_used;
7313                 ret = btrfs_end_transaction(trans, root);
7314                 BUG_ON(ret);
7315                 btrfs_btree_balance_dirty(root, nr);
7316
7317                 kfree(prev_root);
7318                 prev_root = reloc_root;
7319         }
7320         if (prev_root) {
7321                 btrfs_remove_leaf_refs(prev_root, (u64)-1, 0);
7322                 kfree(prev_root);
7323         }
7324         return 0;
7325 }
7326
7327 int btrfs_add_dead_reloc_root(struct btrfs_root *root)
7328 {
7329         list_add(&root->dead_list, &root->fs_info->dead_reloc_roots);
7330         return 0;
7331 }
7332
7333 int btrfs_cleanup_reloc_trees(struct btrfs_root *root)
7334 {
7335         struct btrfs_root *reloc_root;
7336         struct btrfs_trans_handle *trans;
7337         struct btrfs_key location;
7338         int found;
7339         int ret;
7340
7341         mutex_lock(&root->fs_info->tree_reloc_mutex);
7342         ret = btrfs_find_dead_roots(root, BTRFS_TREE_RELOC_OBJECTID, NULL);
7343         BUG_ON(ret);
7344         found = !list_empty(&root->fs_info->dead_reloc_roots);
7345         mutex_unlock(&root->fs_info->tree_reloc_mutex);
7346
7347         if (found) {
7348                 trans = btrfs_start_transaction(root, 1);
7349                 BUG_ON(!trans);
7350                 ret = btrfs_commit_transaction(trans, root);
7351                 BUG_ON(ret);
7352         }
7353
7354         location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
7355         location.offset = (u64)-1;
7356         location.type = BTRFS_ROOT_ITEM_KEY;
7357
7358         reloc_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
7359         BUG_ON(!reloc_root);
7360         btrfs_orphan_cleanup(reloc_root);
7361         return 0;
7362 }
7363
7364 static noinline int init_reloc_tree(struct btrfs_trans_handle *trans,
7365                                     struct btrfs_root *root)
7366 {
7367         struct btrfs_root *reloc_root;
7368         struct extent_buffer *eb;
7369         struct btrfs_root_item *root_item;
7370         struct btrfs_key root_key;
7371         int ret;
7372
7373         BUG_ON(!root->ref_cows);
7374         if (root->reloc_root)
7375                 return 0;
7376
7377         root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
7378         BUG_ON(!root_item);
7379
7380         ret = btrfs_copy_root(trans, root, root->commit_root,
7381                               &eb, BTRFS_TREE_RELOC_OBJECTID);
7382         BUG_ON(ret);
7383
7384         root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
7385         root_key.offset = root->root_key.objectid;
7386         root_key.type = BTRFS_ROOT_ITEM_KEY;
7387
7388         memcpy(root_item, &root->root_item, sizeof(root_item));
7389         btrfs_set_root_refs(root_item, 0);
7390         btrfs_set_root_bytenr(root_item, eb->start);
7391         btrfs_set_root_level(root_item, btrfs_header_level(eb));
7392         btrfs_set_root_generation(root_item, trans->transid);
7393
7394         btrfs_tree_unlock(eb);
7395         free_extent_buffer(eb);
7396
7397         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
7398                                 &root_key, root_item);
7399         BUG_ON(ret);
7400         kfree(root_item);
7401
7402         reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
7403                                                  &root_key);
7404         BUG_ON(!reloc_root);
7405         reloc_root->last_trans = trans->transid;
7406         reloc_root->commit_root = NULL;
7407         reloc_root->ref_tree = &root->fs_info->reloc_ref_tree;
7408
7409         root->reloc_root = reloc_root;
7410         return 0;
7411 }
7412
7413 /*
7414  * Core function of space balance.
7415  *
7416  * The idea is using reloc trees to relocate tree blocks in reference
7417  * counted roots. There is one reloc tree for each subvol, and all
7418  * reloc trees share same root key objectid. Reloc trees are snapshots
7419  * of the latest committed roots of subvols (root->commit_root).
7420  *
7421  * To relocate a tree block referenced by a subvol, there are two steps.
7422  * COW the block through subvol's reloc tree, then update block pointer
7423  * in the subvol to point to the new block. Since all reloc trees share
7424  * same root key objectid, doing special handing for tree blocks owned
7425  * by them is easy. Once a tree block has been COWed in one reloc tree,
7426  * we can use the resulting new block directly when the same block is
7427  * required to COW again through other reloc trees. By this way, relocated
7428  * tree blocks are shared between reloc trees, so they are also shared
7429  * between subvols.
7430  */
7431 static noinline int relocate_one_path(struct btrfs_trans_handle *trans,
7432                                       struct btrfs_root *root,
7433                                       struct btrfs_path *path,
7434                                       struct btrfs_key *first_key,
7435                                       struct btrfs_ref_path *ref_path,
7436                                       struct btrfs_block_group_cache *group,
7437                                       struct inode *reloc_inode)
7438 {
7439         struct btrfs_root *reloc_root;
7440         struct extent_buffer *eb = NULL;
7441         struct btrfs_key *keys;
7442         u64 *nodes;
7443         int level;
7444         int shared_level;
7445         int lowest_level = 0;
7446         int ret;
7447
7448         if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
7449                 lowest_level = ref_path->owner_objectid;
7450
7451         if (!root->ref_cows) {
7452                 path->lowest_level = lowest_level;
7453                 ret = btrfs_search_slot(trans, root, first_key, path, 0, 1);
7454                 BUG_ON(ret < 0);
7455                 path->lowest_level = 0;
7456                 btrfs_release_path(root, path);
7457                 return 0;
7458         }
7459
7460         mutex_lock(&root->fs_info->tree_reloc_mutex);
7461         ret = init_reloc_tree(trans, root);
7462         BUG_ON(ret);
7463         reloc_root = root->reloc_root;
7464
7465         shared_level = ref_path->shared_level;
7466         ref_path->shared_level = BTRFS_MAX_LEVEL - 1;
7467
7468         keys = ref_path->node_keys;
7469         nodes = ref_path->new_nodes;
7470         memset(&keys[shared_level + 1], 0,
7471                sizeof(*keys) * (BTRFS_MAX_LEVEL - shared_level - 1));
7472         memset(&nodes[shared_level + 1], 0,
7473                sizeof(*nodes) * (BTRFS_MAX_LEVEL - shared_level - 1));
7474
7475         if (nodes[lowest_level] == 0) {
7476                 path->lowest_level = lowest_level;
7477                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
7478                                         0, 1);
7479                 BUG_ON(ret);
7480                 for (level = lowest_level; level < BTRFS_MAX_LEVEL; level++) {
7481                         eb = path->nodes[level];
7482                         if (!eb || eb == reloc_root->node)
7483                                 break;
7484                         nodes[level] = eb->start;
7485                         if (level == 0)
7486                                 btrfs_item_key_to_cpu(eb, &keys[level], 0);
7487                         else
7488                                 btrfs_node_key_to_cpu(eb, &keys[level], 0);
7489                 }
7490                 if (nodes[0] &&
7491                     ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
7492                         eb = path->nodes[0];
7493                         ret = replace_extents_in_leaf(trans, reloc_root, eb,
7494                                                       group, reloc_inode);
7495                         BUG_ON(ret);
7496                 }
7497                 btrfs_release_path(reloc_root, path);
7498         } else {
7499                 ret = btrfs_merge_path(trans, reloc_root, keys, nodes,
7500                                        lowest_level);
7501                 BUG_ON(ret);
7502         }
7503
7504         /*
7505          * replace tree blocks in the fs tree with tree blocks in
7506          * the reloc tree.
7507          */
7508         ret = btrfs_merge_path(trans, root, keys, nodes, lowest_level);
7509         BUG_ON(ret < 0);
7510
7511         if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
7512                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
7513                                         0, 0);
7514                 BUG_ON(ret);
7515                 extent_buffer_get(path->nodes[0]);
7516                 eb = path->nodes[0];
7517                 btrfs_release_path(reloc_root, path);
7518                 ret = invalidate_extent_cache(reloc_root, eb, group, root);
7519                 BUG_ON(ret);
7520                 free_extent_buffer(eb);
7521         }
7522
7523         mutex_unlock(&root->fs_info->tree_reloc_mutex);
7524         path->lowest_level = 0;
7525         return 0;
7526 }
7527
7528 static noinline int relocate_tree_block(struct btrfs_trans_handle *trans,
7529                                         struct btrfs_root *root,
7530                                         struct btrfs_path *path,
7531                                         struct btrfs_key *first_key,
7532                                         struct btrfs_ref_path *ref_path)
7533 {
7534         int ret;
7535
7536         ret = relocate_one_path(trans, root, path, first_key,
7537                                 ref_path, NULL, NULL);
7538         BUG_ON(ret);
7539
7540         return 0;
7541 }
7542
7543 static noinline int del_extent_zero(struct btrfs_trans_handle *trans,
7544                                     struct btrfs_root *extent_root,
7545                                     struct btrfs_path *path,
7546                                     struct btrfs_key *extent_key)
7547 {
7548         int ret;
7549
7550         ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
7551         if (ret)
7552                 goto out;
7553         ret = btrfs_del_item(trans, extent_root, path);
7554 out:
7555         btrfs_release_path(extent_root, path);
7556         return ret;
7557 }
7558
7559 static noinline struct btrfs_root *read_ref_root(struct btrfs_fs_info *fs_info,
7560                                                 struct btrfs_ref_path *ref_path)
7561 {
7562         struct btrfs_key root_key;
7563
7564         root_key.objectid = ref_path->root_objectid;
7565         root_key.type = BTRFS_ROOT_ITEM_KEY;
7566         if (is_cowonly_root(ref_path->root_objectid))
7567                 root_key.offset = 0;
7568         else
7569                 root_key.offset = (u64)-1;
7570
7571         return btrfs_read_fs_root_no_name(fs_info, &root_key);
7572 }
7573
7574 static noinline int relocate_one_extent(struct btrfs_root *extent_root,
7575                                         struct btrfs_path *path,
7576                                         struct btrfs_key *extent_key,
7577                                         struct btrfs_block_group_cache *group,
7578                                         struct inode *reloc_inode, int pass)
7579 {
7580         struct btrfs_trans_handle *trans;
7581         struct btrfs_root *found_root;
7582         struct btrfs_ref_path *ref_path = NULL;
7583         struct disk_extent *new_extents = NULL;
7584         int nr_extents = 0;
7585         int loops;
7586         int ret;
7587         int level;
7588         struct btrfs_key first_key;
7589         u64 prev_block = 0;
7590
7591
7592         trans = btrfs_start_transaction(extent_root, 1);
7593         BUG_ON(!trans);
7594
7595         if (extent_key->objectid == 0) {
7596                 ret = del_extent_zero(trans, extent_root, path, extent_key);
7597                 goto out;
7598         }
7599
7600         ref_path = kmalloc(sizeof(*ref_path), GFP_NOFS);
7601         if (!ref_path) {
7602                 ret = -ENOMEM;
7603                 goto out;
7604         }
7605
7606         for (loops = 0; ; loops++) {
7607                 if (loops == 0) {
7608                         ret = btrfs_first_ref_path(trans, extent_root, ref_path,
7609                                                    extent_key->objectid);
7610                 } else {
7611                         ret = btrfs_next_ref_path(trans, extent_root, ref_path);
7612                 }
7613                 if (ret < 0)
7614                         goto out;
7615                 if (ret > 0)
7616                         break;
7617
7618                 if (ref_path->root_objectid == BTRFS_TREE_LOG_OBJECTID ||
7619                     ref_path->root_objectid == BTRFS_TREE_RELOC_OBJECTID)
7620                         continue;
7621
7622                 found_root = read_ref_root(extent_root->fs_info, ref_path);
7623                 BUG_ON(!found_root);
7624                 /*
7625                  * for reference counted tree, only process reference paths
7626                  * rooted at the latest committed root.
7627                  */
7628                 if (found_root->ref_cows &&
7629                     ref_path->root_generation != found_root->root_key.offset)
7630                         continue;
7631
7632                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
7633                         if (pass == 0) {
7634                                 /*
7635                                  * copy data extents to new locations
7636                                  */
7637                                 u64 group_start = group->key.objectid;
7638                                 ret = relocate_data_extent(reloc_inode,
7639                                                            extent_key,
7640                                                            group_start);
7641                                 if (ret < 0)
7642                                         goto out;
7643                                 break;
7644                         }
7645                         level = 0;
7646                 } else {
7647                         level = ref_path->owner_objectid;
7648                 }
7649
7650                 if (prev_block != ref_path->nodes[level]) {
7651                         struct extent_buffer *eb;
7652                         u64 block_start = ref_path->nodes[level];
7653                         u64 block_size = btrfs_level_size(found_root, level);
7654
7655                         eb = read_tree_block(found_root, block_start,
7656                                              block_size, 0);
7657                         btrfs_tree_lock(eb);
7658                         BUG_ON(level != btrfs_header_level(eb));
7659
7660                         if (level == 0)
7661                                 btrfs_item_key_to_cpu(eb, &first_key, 0);
7662                         else
7663                                 btrfs_node_key_to_cpu(eb, &first_key, 0);
7664
7665                         btrfs_tree_unlock(eb);
7666                         free_extent_buffer(eb);
7667                         prev_block = block_start;
7668                 }
7669
7670                 mutex_lock(&extent_root->fs_info->trans_mutex);
7671                 btrfs_record_root_in_trans(found_root);
7672                 mutex_unlock(&extent_root->fs_info->trans_mutex);
7673                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
7674                         /*
7675                          * try to update data extent references while
7676                          * keeping metadata shared between snapshots.
7677                          */
7678                         if (pass == 1) {
7679                                 ret = relocate_one_path(trans, found_root,
7680                                                 path, &first_key, ref_path,
7681                                                 group, reloc_inode);
7682                                 if (ret < 0)
7683                                         goto out;
7684                                 continue;
7685                         }
7686                         /*
7687                          * use fallback method to process the remaining
7688                          * references.
7689                          */
7690                         if (!new_extents) {
7691                                 u64 group_start = group->key.objectid;
7692                                 new_extents = kmalloc(sizeof(*new_extents),
7693                                                       GFP_NOFS);
7694                                 nr_extents = 1;
7695                                 ret = get_new_locations(reloc_inode,
7696                                                         extent_key,
7697                                                         group_start, 1,
7698                                                         &new_extents,
7699                                                         &nr_extents);
7700                                 if (ret)
7701                                         goto out;
7702                         }
7703                         ret = replace_one_extent(trans, found_root,
7704                                                 path, extent_key,
7705                                                 &first_key, ref_path,
7706                                                 new_extents, nr_extents);
7707                 } else {
7708                         ret = relocate_tree_block(trans, found_root, path,
7709                                                   &first_key, ref_path);
7710                 }
7711                 if (ret < 0)
7712                         goto out;
7713         }
7714         ret = 0;
7715 out:
7716         btrfs_end_transaction(trans, extent_root);
7717         kfree(new_extents);
7718         kfree(ref_path);
7719         return ret;
7720 }
7721 #endif
7722
7723 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7724 {
7725         u64 num_devices;
7726         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
7727                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7728
7729         num_devices = root->fs_info->fs_devices->rw_devices;
7730         if (num_devices == 1) {
7731                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7732                 stripped = flags & ~stripped;
7733
7734                 /* turn raid0 into single device chunks */
7735                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7736                         return stripped;
7737
7738                 /* turn mirroring into duplication */
7739                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7740                              BTRFS_BLOCK_GROUP_RAID10))
7741                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7742                 return flags;
7743         } else {
7744                 /* they already had raid on here, just return */
7745                 if (flags & stripped)
7746                         return flags;
7747
7748                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7749                 stripped = flags & ~stripped;
7750
7751                 /* switch duplicated blocks with raid1 */
7752                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7753                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7754
7755                 /* turn single device chunks into raid0 */
7756                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
7757         }
7758         return flags;
7759 }
7760
7761 static int set_block_group_ro(struct btrfs_block_group_cache *cache)
7762 {
7763         struct btrfs_space_info *sinfo = cache->space_info;
7764         u64 num_bytes;
7765         int ret = -ENOSPC;
7766
7767         if (cache->ro)
7768                 return 0;
7769
7770         spin_lock(&sinfo->lock);
7771         spin_lock(&cache->lock);
7772         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7773                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7774
7775         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7776             sinfo->bytes_may_use + sinfo->bytes_readonly +
7777             cache->reserved_pinned + num_bytes < sinfo->total_bytes) {
7778                 sinfo->bytes_readonly += num_bytes;
7779                 sinfo->bytes_reserved += cache->reserved_pinned;
7780                 cache->reserved_pinned = 0;
7781                 cache->ro = 1;
7782                 ret = 0;
7783         }
7784         spin_unlock(&cache->lock);
7785         spin_unlock(&sinfo->lock);
7786         return ret;
7787 }
7788
7789 int btrfs_set_block_group_ro(struct btrfs_root *root,
7790                              struct btrfs_block_group_cache *cache)
7791
7792 {
7793         struct btrfs_trans_handle *trans;
7794         u64 alloc_flags;
7795         int ret;
7796
7797         BUG_ON(cache->ro);
7798
7799         trans = btrfs_join_transaction(root, 1);
7800         BUG_ON(IS_ERR(trans));
7801
7802         alloc_flags = update_block_group_flags(root, cache->flags);
7803         if (alloc_flags != cache->flags)
7804                 do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags, 1);
7805
7806         ret = set_block_group_ro(cache);
7807         if (!ret)
7808                 goto out;
7809         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7810         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags, 1);
7811         if (ret < 0)
7812                 goto out;
7813         ret = set_block_group_ro(cache);
7814 out:
7815         btrfs_end_transaction(trans, root);
7816         return ret;
7817 }
7818
7819 int btrfs_set_block_group_rw(struct btrfs_root *root,
7820                               struct btrfs_block_group_cache *cache)
7821 {
7822         struct btrfs_space_info *sinfo = cache->space_info;
7823         u64 num_bytes;
7824
7825         BUG_ON(!cache->ro);
7826
7827         spin_lock(&sinfo->lock);
7828         spin_lock(&cache->lock);
7829         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7830                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7831         sinfo->bytes_readonly -= num_bytes;
7832         cache->ro = 0;
7833         spin_unlock(&cache->lock);
7834         spin_unlock(&sinfo->lock);
7835         return 0;
7836 }
7837
7838 /*
7839  * checks to see if its even possible to relocate this block group.
7840  *
7841  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7842  * ok to go ahead and try.
7843  */
7844 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7845 {
7846         struct btrfs_block_group_cache *block_group;
7847         struct btrfs_space_info *space_info;
7848         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7849         struct btrfs_device *device;
7850         int full = 0;
7851         int ret = 0;
7852
7853         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7854
7855         /* odd, couldn't find the block group, leave it alone */
7856         if (!block_group)
7857                 return -1;
7858
7859         /* no bytes used, we're good */
7860         if (!btrfs_block_group_used(&block_group->item))
7861                 goto out;
7862
7863         space_info = block_group->space_info;
7864         spin_lock(&space_info->lock);
7865
7866         full = space_info->full;
7867
7868         /*
7869          * if this is the last block group we have in this space, we can't
7870          * relocate it unless we're able to allocate a new chunk below.
7871          *
7872          * Otherwise, we need to make sure we have room in the space to handle
7873          * all of the extents from this block group.  If we can, we're good
7874          */
7875         if ((space_info->total_bytes != block_group->key.offset) &&
7876            (space_info->bytes_used + space_info->bytes_reserved +
7877             space_info->bytes_pinned + space_info->bytes_readonly +
7878             btrfs_block_group_used(&block_group->item) <
7879             space_info->total_bytes)) {
7880                 spin_unlock(&space_info->lock);
7881                 goto out;
7882         }
7883         spin_unlock(&space_info->lock);
7884
7885         /*
7886          * ok we don't have enough space, but maybe we have free space on our
7887          * devices to allocate new chunks for relocation, so loop through our
7888          * alloc devices and guess if we have enough space.  However, if we
7889          * were marked as full, then we know there aren't enough chunks, and we
7890          * can just return.
7891          */
7892         ret = -1;
7893         if (full)
7894                 goto out;
7895
7896         mutex_lock(&root->fs_info->chunk_mutex);
7897         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7898                 u64 min_free = btrfs_block_group_used(&block_group->item);
7899                 u64 dev_offset, max_avail;
7900
7901                 /*
7902                  * check to make sure we can actually find a chunk with enough
7903                  * space to fit our block group in.
7904                  */
7905                 if (device->total_bytes > device->bytes_used + min_free) {
7906                         ret = find_free_dev_extent(NULL, device, min_free,
7907                                                    &dev_offset, &max_avail);
7908                         if (!ret)
7909                                 break;
7910                         ret = -1;
7911                 }
7912         }
7913         mutex_unlock(&root->fs_info->chunk_mutex);
7914 out:
7915         btrfs_put_block_group(block_group);
7916         return ret;
7917 }
7918
7919 static int find_first_block_group(struct btrfs_root *root,
7920                 struct btrfs_path *path, struct btrfs_key *key)
7921 {
7922         int ret = 0;
7923         struct btrfs_key found_key;
7924         struct extent_buffer *leaf;
7925         int slot;
7926
7927         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7928         if (ret < 0)
7929                 goto out;
7930
7931         while (1) {
7932                 slot = path->slots[0];
7933                 leaf = path->nodes[0];
7934                 if (slot >= btrfs_header_nritems(leaf)) {
7935                         ret = btrfs_next_leaf(root, path);
7936                         if (ret == 0)
7937                                 continue;
7938                         if (ret < 0)
7939                                 goto out;
7940                         break;
7941                 }
7942                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7943
7944                 if (found_key.objectid >= key->objectid &&
7945                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7946                         ret = 0;
7947                         goto out;
7948                 }
7949                 path->slots[0]++;
7950         }
7951 out:
7952         return ret;
7953 }
7954
7955 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7956 {
7957         struct btrfs_block_group_cache *block_group;
7958         u64 last = 0;
7959
7960         while (1) {
7961                 struct inode *inode;
7962
7963                 block_group = btrfs_lookup_first_block_group(info, last);
7964                 while (block_group) {
7965                         spin_lock(&block_group->lock);
7966                         if (block_group->iref)
7967                                 break;
7968                         spin_unlock(&block_group->lock);
7969                         block_group = next_block_group(info->tree_root,
7970                                                        block_group);
7971                 }
7972                 if (!block_group) {
7973                         if (last == 0)
7974                                 break;
7975                         last = 0;
7976                         continue;
7977                 }
7978
7979                 inode = block_group->inode;
7980                 block_group->iref = 0;
7981                 block_group->inode = NULL;
7982                 spin_unlock(&block_group->lock);
7983                 iput(inode);
7984                 last = block_group->key.objectid + block_group->key.offset;
7985                 btrfs_put_block_group(block_group);
7986         }
7987 }
7988
7989 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7990 {
7991         struct btrfs_block_group_cache *block_group;
7992         struct btrfs_space_info *space_info;
7993         struct btrfs_caching_control *caching_ctl;
7994         struct rb_node *n;
7995
7996         down_write(&info->extent_commit_sem);
7997         while (!list_empty(&info->caching_block_groups)) {
7998                 caching_ctl = list_entry(info->caching_block_groups.next,
7999                                          struct btrfs_caching_control, list);
8000                 list_del(&caching_ctl->list);
8001                 put_caching_control(caching_ctl);
8002         }
8003         up_write(&info->extent_commit_sem);
8004
8005         spin_lock(&info->block_group_cache_lock);
8006         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
8007                 block_group = rb_entry(n, struct btrfs_block_group_cache,
8008                                        cache_node);
8009                 rb_erase(&block_group->cache_node,
8010                          &info->block_group_cache_tree);
8011                 spin_unlock(&info->block_group_cache_lock);
8012
8013                 down_write(&block_group->space_info->groups_sem);
8014                 list_del(&block_group->list);
8015                 up_write(&block_group->space_info->groups_sem);
8016
8017                 if (block_group->cached == BTRFS_CACHE_STARTED)
8018                         wait_block_group_cache_done(block_group);
8019
8020                 btrfs_remove_free_space_cache(block_group);
8021                 btrfs_put_block_group(block_group);
8022
8023                 spin_lock(&info->block_group_cache_lock);
8024         }
8025         spin_unlock(&info->block_group_cache_lock);
8026
8027         /* now that all the block groups are freed, go through and
8028          * free all the space_info structs.  This is only called during
8029          * the final stages of unmount, and so we know nobody is
8030          * using them.  We call synchronize_rcu() once before we start,
8031          * just to be on the safe side.
8032          */
8033         synchronize_rcu();
8034
8035         release_global_block_rsv(info);
8036
8037         while(!list_empty(&info->space_info)) {
8038                 space_info = list_entry(info->space_info.next,
8039                                         struct btrfs_space_info,
8040                                         list);
8041                 if (space_info->bytes_pinned > 0 ||
8042                     space_info->bytes_reserved > 0) {
8043                         WARN_ON(1);
8044                         dump_space_info(space_info, 0, 0);
8045                 }
8046                 list_del(&space_info->list);
8047                 kfree(space_info);
8048         }
8049         return 0;
8050 }
8051
8052 static void __link_block_group(struct btrfs_space_info *space_info,
8053                                struct btrfs_block_group_cache *cache)
8054 {
8055         int index = get_block_group_index(cache);
8056
8057         down_write(&space_info->groups_sem);
8058         list_add_tail(&cache->list, &space_info->block_groups[index]);
8059         up_write(&space_info->groups_sem);
8060 }
8061
8062 int btrfs_read_block_groups(struct btrfs_root *root)
8063 {
8064         struct btrfs_path *path;
8065         int ret;
8066         struct btrfs_block_group_cache *cache;
8067         struct btrfs_fs_info *info = root->fs_info;
8068         struct btrfs_space_info *space_info;
8069         struct btrfs_key key;
8070         struct btrfs_key found_key;
8071         struct extent_buffer *leaf;
8072         int need_clear = 0;
8073         u64 cache_gen;
8074
8075         root = info->extent_root;
8076         key.objectid = 0;
8077         key.offset = 0;
8078         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
8079         path = btrfs_alloc_path();
8080         if (!path)
8081                 return -ENOMEM;
8082
8083         cache_gen = btrfs_super_cache_generation(&root->fs_info->super_copy);
8084         if (cache_gen != 0 &&
8085             btrfs_super_generation(&root->fs_info->super_copy) != cache_gen)
8086                 need_clear = 1;
8087
8088         while (1) {
8089                 ret = find_first_block_group(root, path, &key);
8090                 if (ret > 0)
8091                         break;
8092                 if (ret != 0)
8093                         goto error;
8094
8095                 leaf = path->nodes[0];
8096                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
8097                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
8098                 if (!cache) {
8099                         ret = -ENOMEM;
8100                         goto error;
8101                 }
8102
8103                 atomic_set(&cache->count, 1);
8104                 spin_lock_init(&cache->lock);
8105                 spin_lock_init(&cache->tree_lock);
8106                 cache->fs_info = info;
8107                 INIT_LIST_HEAD(&cache->list);
8108                 INIT_LIST_HEAD(&cache->cluster_list);
8109
8110                 if (need_clear)
8111                         cache->disk_cache_state = BTRFS_DC_CLEAR;
8112
8113                 /*
8114                  * we only want to have 32k of ram per block group for keeping
8115                  * track of free space, and if we pass 1/2 of that we want to
8116                  * start converting things over to using bitmaps
8117                  */
8118                 cache->extents_thresh = ((1024 * 32) / 2) /
8119                         sizeof(struct btrfs_free_space);
8120
8121                 read_extent_buffer(leaf, &cache->item,
8122                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
8123                                    sizeof(cache->item));
8124                 memcpy(&cache->key, &found_key, sizeof(found_key));
8125
8126                 key.objectid = found_key.objectid + found_key.offset;
8127                 btrfs_release_path(root, path);
8128                 cache->flags = btrfs_block_group_flags(&cache->item);
8129                 cache->sectorsize = root->sectorsize;
8130
8131                 /*
8132                  * check for two cases, either we are full, and therefore
8133                  * don't need to bother with the caching work since we won't
8134                  * find any space, or we are empty, and we can just add all
8135                  * the space in and be done with it.  This saves us _alot_ of
8136                  * time, particularly in the full case.
8137                  */
8138                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
8139                         exclude_super_stripes(root, cache);
8140                         cache->last_byte_to_unpin = (u64)-1;
8141                         cache->cached = BTRFS_CACHE_FINISHED;
8142                         free_excluded_extents(root, cache);
8143                 } else if (btrfs_block_group_used(&cache->item) == 0) {
8144                         exclude_super_stripes(root, cache);
8145                         cache->last_byte_to_unpin = (u64)-1;
8146                         cache->cached = BTRFS_CACHE_FINISHED;
8147                         add_new_free_space(cache, root->fs_info,
8148                                            found_key.objectid,
8149                                            found_key.objectid +
8150                                            found_key.offset);
8151                         free_excluded_extents(root, cache);
8152                 }
8153
8154                 ret = update_space_info(info, cache->flags, found_key.offset,
8155                                         btrfs_block_group_used(&cache->item),
8156                                         &space_info);
8157                 BUG_ON(ret);
8158                 cache->space_info = space_info;
8159                 spin_lock(&cache->space_info->lock);
8160                 cache->space_info->bytes_readonly += cache->bytes_super;
8161                 spin_unlock(&cache->space_info->lock);
8162
8163                 __link_block_group(space_info, cache);
8164
8165                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
8166                 BUG_ON(ret);
8167
8168                 set_avail_alloc_bits(root->fs_info, cache->flags);
8169                 if (btrfs_chunk_readonly(root, cache->key.objectid))
8170                         set_block_group_ro(cache);
8171         }
8172
8173         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
8174                 if (!(get_alloc_profile(root, space_info->flags) &
8175                       (BTRFS_BLOCK_GROUP_RAID10 |
8176                        BTRFS_BLOCK_GROUP_RAID1 |
8177                        BTRFS_BLOCK_GROUP_DUP)))
8178                         continue;
8179                 /*
8180                  * avoid allocating from un-mirrored block group if there are
8181                  * mirrored block groups.
8182                  */
8183                 list_for_each_entry(cache, &space_info->block_groups[3], list)
8184                         set_block_group_ro(cache);
8185                 list_for_each_entry(cache, &space_info->block_groups[4], list)
8186                         set_block_group_ro(cache);
8187         }
8188
8189         init_global_block_rsv(info);
8190         ret = 0;
8191 error:
8192         btrfs_free_path(path);
8193         return ret;
8194 }
8195
8196 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
8197                            struct btrfs_root *root, u64 bytes_used,
8198                            u64 type, u64 chunk_objectid, u64 chunk_offset,
8199                            u64 size)
8200 {
8201         int ret;
8202         struct btrfs_root *extent_root;
8203         struct btrfs_block_group_cache *cache;
8204
8205         extent_root = root->fs_info->extent_root;
8206
8207         root->fs_info->last_trans_log_full_commit = trans->transid;
8208
8209         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8210         if (!cache)
8211                 return -ENOMEM;
8212
8213         cache->key.objectid = chunk_offset;
8214         cache->key.offset = size;
8215         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8216         cache->sectorsize = root->sectorsize;
8217         cache->fs_info = root->fs_info;
8218
8219         /*
8220          * we only want to have 32k of ram per block group for keeping track
8221          * of free space, and if we pass 1/2 of that we want to start
8222          * converting things over to using bitmaps
8223          */
8224         cache->extents_thresh = ((1024 * 32) / 2) /
8225                 sizeof(struct btrfs_free_space);
8226         atomic_set(&cache->count, 1);
8227         spin_lock_init(&cache->lock);
8228         spin_lock_init(&cache->tree_lock);
8229         INIT_LIST_HEAD(&cache->list);
8230         INIT_LIST_HEAD(&cache->cluster_list);
8231
8232         btrfs_set_block_group_used(&cache->item, bytes_used);
8233         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
8234         cache->flags = type;
8235         btrfs_set_block_group_flags(&cache->item, type);
8236
8237         cache->last_byte_to_unpin = (u64)-1;
8238         cache->cached = BTRFS_CACHE_FINISHED;
8239         exclude_super_stripes(root, cache);
8240
8241         add_new_free_space(cache, root->fs_info, chunk_offset,
8242                            chunk_offset + size);
8243
8244         free_excluded_extents(root, cache);
8245
8246         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
8247                                 &cache->space_info);
8248         BUG_ON(ret);
8249
8250         spin_lock(&cache->space_info->lock);
8251         cache->space_info->bytes_readonly += cache->bytes_super;
8252         spin_unlock(&cache->space_info->lock);
8253
8254         __link_block_group(cache->space_info, cache);
8255
8256         ret = btrfs_add_block_group_cache(root->fs_info, cache);
8257         BUG_ON(ret);
8258
8259         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
8260                                 sizeof(cache->item));
8261         BUG_ON(ret);
8262
8263         set_avail_alloc_bits(extent_root->fs_info, type);
8264
8265         return 0;
8266 }
8267
8268 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
8269                              struct btrfs_root *root, u64 group_start)
8270 {
8271         struct btrfs_path *path;
8272         struct btrfs_block_group_cache *block_group;
8273         struct btrfs_free_cluster *cluster;
8274         struct btrfs_root *tree_root = root->fs_info->tree_root;
8275         struct btrfs_key key;
8276         struct inode *inode;
8277         int ret;
8278
8279         root = root->fs_info->extent_root;
8280
8281         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
8282         BUG_ON(!block_group);
8283         BUG_ON(!block_group->ro);
8284
8285         /* make sure this block group isn't part of an allocation cluster */
8286         cluster = &root->fs_info->data_alloc_cluster;
8287         spin_lock(&cluster->refill_lock);
8288         btrfs_return_cluster_to_free_space(block_group, cluster);
8289         spin_unlock(&cluster->refill_lock);
8290
8291         /*
8292          * make sure this block group isn't part of a metadata
8293          * allocation cluster
8294          */
8295         cluster = &root->fs_info->meta_alloc_cluster;
8296         spin_lock(&cluster->refill_lock);
8297         btrfs_return_cluster_to_free_space(block_group, cluster);
8298         spin_unlock(&cluster->refill_lock);
8299
8300         path = btrfs_alloc_path();
8301         BUG_ON(!path);
8302
8303         inode = lookup_free_space_inode(root, block_group, path);
8304         if (!IS_ERR(inode)) {
8305                 btrfs_orphan_add(trans, inode);
8306                 clear_nlink(inode);
8307                 /* One for the block groups ref */
8308                 spin_lock(&block_group->lock);
8309                 if (block_group->iref) {
8310                         block_group->iref = 0;
8311                         block_group->inode = NULL;
8312                         spin_unlock(&block_group->lock);
8313                         iput(inode);
8314                 } else {
8315                         spin_unlock(&block_group->lock);
8316                 }
8317                 /* One for our lookup ref */
8318                 iput(inode);
8319         }
8320
8321         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
8322         key.offset = block_group->key.objectid;
8323         key.type = 0;
8324
8325         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
8326         if (ret < 0)
8327                 goto out;
8328         if (ret > 0)
8329                 btrfs_release_path(tree_root, path);
8330         if (ret == 0) {
8331                 ret = btrfs_del_item(trans, tree_root, path);
8332                 if (ret)
8333                         goto out;
8334                 btrfs_release_path(tree_root, path);
8335         }
8336
8337         spin_lock(&root->fs_info->block_group_cache_lock);
8338         rb_erase(&block_group->cache_node,
8339                  &root->fs_info->block_group_cache_tree);
8340         spin_unlock(&root->fs_info->block_group_cache_lock);
8341
8342         down_write(&block_group->space_info->groups_sem);
8343         /*
8344          * we must use list_del_init so people can check to see if they
8345          * are still on the list after taking the semaphore
8346          */
8347         list_del_init(&block_group->list);
8348         up_write(&block_group->space_info->groups_sem);
8349
8350         if (block_group->cached == BTRFS_CACHE_STARTED)
8351                 wait_block_group_cache_done(block_group);
8352
8353         btrfs_remove_free_space_cache(block_group);
8354
8355         spin_lock(&block_group->space_info->lock);
8356         block_group->space_info->total_bytes -= block_group->key.offset;
8357         block_group->space_info->bytes_readonly -= block_group->key.offset;
8358         spin_unlock(&block_group->space_info->lock);
8359
8360         memcpy(&key, &block_group->key, sizeof(key));
8361
8362         btrfs_clear_space_info_full(root->fs_info);
8363
8364         btrfs_put_block_group(block_group);
8365         btrfs_put_block_group(block_group);
8366
8367         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8368         if (ret > 0)
8369                 ret = -EIO;
8370         if (ret < 0)
8371                 goto out;
8372
8373         ret = btrfs_del_item(trans, root, path);
8374 out:
8375         btrfs_free_path(path);
8376         return ret;
8377 }