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 /* control flags for do_chunk_alloc's force field
  37  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  38  * if we really need one.
  39  *
  40  * CHUNK_ALLOC_FORCE means it must try to allocate one
  41  *
  42  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  43  * if we have very few chunks already allocated.  This is
  44  * used as part of the clustering code to help make sure
  45  * we have a good pool of storage to cluster in, without
  46  * filling the FS with empty chunks
  47  *
  48  */
  49 enum {
  50         CHUNK_ALLOC_NO_FORCE = 0,
  51         CHUNK_ALLOC_FORCE = 1,
  52         CHUNK_ALLOC_LIMITED = 2,
  53 };
  54
  55 static int update_block_group(struct btrfs_trans_handle *trans,
  56                               struct btrfs_root *root,
  57                               u64 bytenr, u64 num_bytes, int alloc);
  58 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  59                                 struct btrfs_root *root,
  60                                 u64 bytenr, u64 num_bytes, u64 parent,
  61                                 u64 root_objectid, u64 owner_objectid,
  62                                 u64 owner_offset, int refs_to_drop,
  63                                 struct btrfs_delayed_extent_op *extra_op);
  64 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  65                                     struct extent_buffer *leaf,
  66                                     struct btrfs_extent_item *ei);
  67 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  68                                       struct btrfs_root *root,
  69                                       u64 parent, u64 root_objectid,
  70                                       u64 flags, u64 owner, u64 offset,
  71                                       struct btrfs_key *ins, int ref_mod);
  72 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  73                                      struct btrfs_root *root,
  74                                      u64 parent, u64 root_objectid,
  75                                      u64 flags, struct btrfs_disk_key *key,
  76                                      int level, struct btrfs_key *ins);
  77 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  78                           struct btrfs_root *extent_root, u64 alloc_bytes,
  79                           u64 flags, int force);
  80 static int find_next_key(struct btrfs_path *path, int level,
  81                          struct btrfs_key *key);
  82 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
  83                             int dump_block_groups);
  84
  85 static noinline int
  86 block_group_cache_done(struct btrfs_block_group_cache *cache)
  87 {
  88         smp_mb();
  89         return cache->cached == BTRFS_CACHE_FINISHED;
  90 }
  91
  92 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  93 {
  94         return (cache->flags & bits) == bits;
  95 }
  96
  97 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
  98 {
  99         atomic_inc(&cache->count);
 100 }
 101
 102 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 103 {
 104         if (atomic_dec_and_test(&cache->count)) {
 105                 WARN_ON(cache->pinned > 0);
 106                 WARN_ON(cache->reserved > 0);
 107                 WARN_ON(cache->reserved_pinned > 0);
 108                 kfree(cache->free_space_ctl);
 109                 kfree(cache);
 110         }
 111 }
 112
 113 /*
 114  * this adds the block group to the fs_info rb tree for the block group
 115  * cache
 116  */
 117 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 118                                 struct btrfs_block_group_cache *block_group)
 119 {
 120         struct rb_node **p;
 121         struct rb_node *parent = NULL;
 122         struct btrfs_block_group_cache *cache;
 123
 124         spin_lock(&info->block_group_cache_lock);
 125         p = &info->block_group_cache_tree.rb_node;
 126
 127         while (*p) {
 128                 parent = *p;
 129                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 130                                  cache_node);
 131                 if (block_group->key.objectid < cache->key.objectid) {
 132                         p = &(*p)->rb_left;
 133                 } else if (block_group->key.objectid > cache->key.objectid) {
 134                         p = &(*p)->rb_right;
 135                 } else {
 136                         spin_unlock(&info->block_group_cache_lock);
 137                         return -EEXIST;
 138                 }
 139         }
 140
 141         rb_link_node(&block_group->cache_node, parent, p);
 142         rb_insert_color(&block_group->cache_node,
 143                         &info->block_group_cache_tree);
 144         spin_unlock(&info->block_group_cache_lock);
 145
 146         return 0;
 147 }
 148
 149 /*
 150  * This will return the block group at or after bytenr if contains is 0, else
 151  * it will return the block group that contains the bytenr
 152  */
 153 static struct btrfs_block_group_cache *
 154 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 155                               int contains)
 156 {
 157         struct btrfs_block_group_cache *cache, *ret = NULL;
 158         struct rb_node *n;
 159         u64 end, start;
 160
 161         spin_lock(&info->block_group_cache_lock);
 162         n = info->block_group_cache_tree.rb_node;
 163
 164         while (n) {
 165                 cache = rb_entry(n, struct btrfs_block_group_cache,
 166                                  cache_node);
 167                 end = cache->key.objectid + cache->key.offset - 1;
 168                 start = cache->key.objectid;
 169
 170                 if (bytenr < start) {
 171                         if (!contains && (!ret || start < ret->key.objectid))
 172                                 ret = cache;
 173                         n = n->rb_left;
 174                 } else if (bytenr > start) {
 175                         if (contains && bytenr <= end) {
 176                                 ret = cache;
 177                                 break;
 178                         }
 179                         n = n->rb_right;
 180                 } else {
 181                         ret = cache;
 182                         break;
 183                 }
 184         }
 185         if (ret)
 186                 btrfs_get_block_group(ret);
 187         spin_unlock(&info->block_group_cache_lock);
 188
 189         return ret;
 190 }
 191
 192 static int add_excluded_extent(struct btrfs_root *root,
 193                                u64 start, u64 num_bytes)
 194 {
 195         u64 end = start + num_bytes - 1;
 196         set_extent_bits(&root->fs_info->freed_extents[0],
 197                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 198         set_extent_bits(&root->fs_info->freed_extents[1],
 199                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 200         return 0;
 201 }
 202
 203 static void free_excluded_extents(struct btrfs_root *root,
 204                                   struct btrfs_block_group_cache *cache)
 205 {
 206         u64 start, end;
 207
 208         start = cache->key.objectid;
 209         end = start + cache->key.offset - 1;
 210
 211         clear_extent_bits(&root->fs_info->freed_extents[0],
 212                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 213         clear_extent_bits(&root->fs_info->freed_extents[1],
 214                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 215 }
 216
 217 static int exclude_super_stripes(struct btrfs_root *root,
 218                                  struct btrfs_block_group_cache *cache)
 219 {
 220         u64 bytenr;
 221         u64 *logical;
 222         int stripe_len;
 223         int i, nr, ret;
 224
 225         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 226                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 227                 cache->bytes_super += stripe_len;
 228                 ret = add_excluded_extent(root, cache->key.objectid,
 229                                           stripe_len);
 230                 BUG_ON(ret);
 231         }
 232
 233         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 234                 bytenr = btrfs_sb_offset(i);
 235                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 236                                        cache->key.objectid, bytenr,
 237                                        0, &logical, &nr, &stripe_len);
 238                 BUG_ON(ret);
 239
 240                 while (nr--) {
 241                         cache->bytes_super += stripe_len;
 242                         ret = add_excluded_extent(root, logical[nr],
 243                                                   stripe_len);
 244                         BUG_ON(ret);
 245                 }
 246
 247                 kfree(logical);
 248         }
 249         return 0;
 250 }
 251
 252 static struct btrfs_caching_control *
 253 get_caching_control(struct btrfs_block_group_cache *cache)
 254 {
 255         struct btrfs_caching_control *ctl;
 256
 257         spin_lock(&cache->lock);
 258         if (cache->cached != BTRFS_CACHE_STARTED) {
 259                 spin_unlock(&cache->lock);
 260                 return NULL;
 261         }
 262
 263         /* We're loading it the fast way, so we don't have a caching_ctl. */
 264         if (!cache->caching_ctl) {
 265                 spin_unlock(&cache->lock);
 266                 return NULL;
 267         }
 268
 269         ctl = cache->caching_ctl;
 270         atomic_inc(&ctl->count);
 271         spin_unlock(&cache->lock);
 272         return ctl;
 273 }
 274
 275 static void put_caching_control(struct btrfs_caching_control *ctl)
 276 {
 277         if (atomic_dec_and_test(&ctl->count))
 278                 kfree(ctl);
 279 }
 280
 281 /*
 282  * this is only called by cache_block_group, since we could have freed extents
 283  * we need to check the pinned_extents for any extents that can't be used yet
 284  * since their free space will be released as soon as the transaction commits.
 285  */
 286 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 287                               struct btrfs_fs_info *info, u64 start, u64 end)
 288 {
 289         u64 extent_start, extent_end, size, total_added = 0;
 290         int ret;
 291
 292         while (start < end) {
 293                 ret = find_first_extent_bit(info->pinned_extents, start,
 294                                             &extent_start, &extent_end,
 295                                             EXTENT_DIRTY | EXTENT_UPTODATE);
 296                 if (ret)
 297                         break;
 298
 299                 if (extent_start <= start) {
 300                         start = extent_end + 1;
 301                 } else if (extent_start > start && extent_start < end) {
 302                         size = extent_start - start;
 303                         total_added += size;
 304                         ret = btrfs_add_free_space(block_group, start,
 305                                                    size);
 306                         BUG_ON(ret);
 307                         start = extent_end + 1;
 308                 } else {
 309                         break;
 310                 }
 311         }
 312
 313         if (start < end) {
 314                 size = end - start;
 315                 total_added += size;
 316                 ret = btrfs_add_free_space(block_group, start, size);
 317                 BUG_ON(ret);
 318         }
 319
 320         return total_added;
 321 }
 322
 323 static int caching_kthread(void *data)
 324 {
 325         struct btrfs_block_group_cache *block_group = data;
 326         struct btrfs_fs_info *fs_info = block_group->fs_info;
 327         struct btrfs_caching_control *caching_ctl = block_group->caching_ctl;
 328         struct btrfs_root *extent_root = fs_info->extent_root;
 329         struct btrfs_path *path;
 330         struct extent_buffer *leaf;
 331         struct btrfs_key key;
 332         u64 total_found = 0;
 333         u64 last = 0;
 334         u32 nritems;
 335         int ret = 0;
 336
 337         path = btrfs_alloc_path();
 338         if (!path)
 339                 return -ENOMEM;
 340
 341         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 342
 343         /*
 344          * We don't want to deadlock with somebody trying to allocate a new
 345          * extent for the extent root while also trying to search the extent
 346          * root to add free space.  So we skip locking and search the commit
 347          * root, since its read-only
 348          */
 349         path->skip_locking = 1;
 350         path->search_commit_root = 1;
 351         path->reada = 1;
 352
 353         key.objectid = last;
 354         key.offset = 0;
 355         key.type = BTRFS_EXTENT_ITEM_KEY;
 356 again:
 357         mutex_lock(&caching_ctl->mutex);
 358         /* need to make sure the commit_root doesn't disappear */
 359         down_read(&fs_info->extent_commit_sem);
 360
 361         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 362         if (ret < 0)
 363                 goto err;
 364
 365         leaf = path->nodes[0];
 366         nritems = btrfs_header_nritems(leaf);
 367
 368         while (1) {
 369                 if (btrfs_fs_closing(fs_info) > 1) {
 370                         last = (u64)-1;
 371                         break;
 372                 }
 373
 374                 if (path->slots[0] < nritems) {
 375                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 376                 } else {
 377                         ret = find_next_key(path, 0, &key);
 378                         if (ret)
 379                                 break;
 380
 381                         if (need_resched() ||
 382                             btrfs_next_leaf(extent_root, path)) {
 383                                 caching_ctl->progress = last;
 384                                 btrfs_release_path(path);
 385                                 up_read(&fs_info->extent_commit_sem);
 386                                 mutex_unlock(&caching_ctl->mutex);
 387                                 cond_resched();
 388                                 goto again;
 389                         }
 390                         leaf = path->nodes[0];
 391                         nritems = btrfs_header_nritems(leaf);
 392                         continue;
 393                 }
 394
 395                 if (key.objectid < block_group->key.objectid) {
 396                         path->slots[0]++;
 397                         continue;
 398                 }
 399
 400                 if (key.objectid >= block_group->key.objectid +
 401                     block_group->key.offset)
 402                         break;
 403
 404                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 405                         total_found += add_new_free_space(block_group,
 406                                                           fs_info, last,
 407                                                           key.objectid);
 408                         last = key.objectid + key.offset;
 409
 410                         if (total_found > (1024 * 1024 * 2)) {
 411                                 total_found = 0;
 412                                 wake_up(&caching_ctl->wait);
 413                         }
 414                 }
 415                 path->slots[0]++;
 416         }
 417         ret = 0;
 418
 419         total_found += add_new_free_space(block_group, fs_info, last,
 420                                           block_group->key.objectid +
 421                                           block_group->key.offset);
 422         caching_ctl->progress = (u64)-1;
 423
 424         spin_lock(&block_group->lock);
 425         block_group->caching_ctl = NULL;
 426         block_group->cached = BTRFS_CACHE_FINISHED;
 427         spin_unlock(&block_group->lock);
 428
 429 err:
 430         btrfs_free_path(path);
 431         up_read(&fs_info->extent_commit_sem);
 432
 433         free_excluded_extents(extent_root, block_group);
 434
 435         mutex_unlock(&caching_ctl->mutex);
 436         wake_up(&caching_ctl->wait);
 437
 438         put_caching_control(caching_ctl);
 439         atomic_dec(&block_group->space_info->caching_threads);
 440         btrfs_put_block_group(block_group);
 441
 442         return 0;
 443 }
 444
 445 static int cache_block_group(struct btrfs_block_group_cache *cache,
 446                              struct btrfs_trans_handle *trans,
 447                              struct btrfs_root *root,
 448                              int load_cache_only)
 449 {
 450         struct btrfs_fs_info *fs_info = cache->fs_info;
 451         struct btrfs_caching_control *caching_ctl;
 452         struct task_struct *tsk;
 453         int ret = 0;
 454
 455         smp_mb();
 456         if (cache->cached != BTRFS_CACHE_NO)
 457                 return 0;
 458
 459         /*
 460          * We can't do the read from on-disk cache during a commit since we need
 461          * to have the normal tree locking.  Also if we are currently trying to
 462          * allocate blocks for the tree root we can't do the fast caching since
 463          * we likely hold important locks.
 464          */
 465         if (trans && (!trans->transaction->in_commit) &&
 466             (root && root != root->fs_info->tree_root)) {
 467                 spin_lock(&cache->lock);
 468                 if (cache->cached != BTRFS_CACHE_NO) {
 469                         spin_unlock(&cache->lock);
 470                         return 0;
 471                 }
 472                 cache->cached = BTRFS_CACHE_STARTED;
 473                 spin_unlock(&cache->lock);
 474
 475                 ret = load_free_space_cache(fs_info, cache);
 476
 477                 spin_lock(&cache->lock);
 478                 if (ret == 1) {
 479                         cache->cached = BTRFS_CACHE_FINISHED;
 480                         cache->last_byte_to_unpin = (u64)-1;
 481                 } else {
 482                         cache->cached = BTRFS_CACHE_NO;
 483                 }
 484                 spin_unlock(&cache->lock);
 485                 if (ret == 1) {
 486                         free_excluded_extents(fs_info->extent_root, cache);
 487                         return 0;
 488                 }
 489         }
 490
 491         if (load_cache_only)
 492                 return 0;
 493
 494         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 495         BUG_ON(!caching_ctl);
 496
 497         INIT_LIST_HEAD(&caching_ctl->list);
 498         mutex_init(&caching_ctl->mutex);
 499         init_waitqueue_head(&caching_ctl->wait);
 500         caching_ctl->block_group = cache;
 501         caching_ctl->progress = cache->key.objectid;
 502         /* one for caching kthread, one for caching block group list */
 503         atomic_set(&caching_ctl->count, 2);
 504
 505         spin_lock(&cache->lock);
 506         if (cache->cached != BTRFS_CACHE_NO) {
 507                 spin_unlock(&cache->lock);
 508                 kfree(caching_ctl);
 509                 return 0;
 510         }
 511         cache->caching_ctl = caching_ctl;
 512         cache->cached = BTRFS_CACHE_STARTED;
 513         spin_unlock(&cache->lock);
 514
 515         down_write(&fs_info->extent_commit_sem);
 516         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 517         up_write(&fs_info->extent_commit_sem);
 518
 519         atomic_inc(&cache->space_info->caching_threads);
 520         btrfs_get_block_group(cache);
 521
 522         tsk = kthread_run(caching_kthread, cache, "btrfs-cache-%llu\n",
 523                           cache->key.objectid);
 524         if (IS_ERR(tsk)) {
 525                 ret = PTR_ERR(tsk);
 526                 printk(KERN_ERR "error running thread %d\n", ret);
 527                 BUG();
 528         }
 529
 530         return ret;
 531 }
 532
 533 /*
 534  * return the block group that starts at or after bytenr
 535  */
 536 static struct btrfs_block_group_cache *
 537 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 538 {
 539         struct btrfs_block_group_cache *cache;
 540
 541         cache = block_group_cache_tree_search(info, bytenr, 0);
 542
 543         return cache;
 544 }
 545
 546 /*
 547  * return the block group that contains the given bytenr
 548  */
 549 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 550                                                  struct btrfs_fs_info *info,
 551                                                  u64 bytenr)
 552 {
 553         struct btrfs_block_group_cache *cache;
 554
 555         cache = block_group_cache_tree_search(info, bytenr, 1);
 556
 557         return cache;
 558 }
 559
 560 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 561                                                   u64 flags)
 562 {
 563         struct list_head *head = &info->space_info;
 564         struct btrfs_space_info *found;
 565
 566         flags &= BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_SYSTEM |
 567                  BTRFS_BLOCK_GROUP_METADATA;
 568
 569         rcu_read_lock();
 570         list_for_each_entry_rcu(found, head, list) {
 571                 if (found->flags & flags) {
 572                         rcu_read_unlock();
 573                         return found;
 574                 }
 575         }
 576         rcu_read_unlock();
 577         return NULL;
 578 }
 579
 580 /*
 581  * after adding space to the filesystem, we need to clear the full flags
 582  * on all the space infos.
 583  */
 584 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 585 {
 586         struct list_head *head = &info->space_info;
 587         struct btrfs_space_info *found;
 588
 589         rcu_read_lock();
 590         list_for_each_entry_rcu(found, head, list)
 591                 found->full = 0;
 592         rcu_read_unlock();
 593 }
 594
 595 static u64 div_factor(u64 num, int factor)
 596 {
 597         if (factor == 10)
 598                 return num;
 599         num *= factor;
 600         do_div(num, 10);
 601         return num;
 602 }
 603
 604 static u64 div_factor_fine(u64 num, int factor)
 605 {
 606         if (factor == 100)
 607                 return num;
 608         num *= factor;
 609         do_div(num, 100);
 610         return num;
 611 }
 612
 613 u64 btrfs_find_block_group(struct btrfs_root *root,
 614                            u64 search_start, u64 search_hint, int owner)
 615 {
 616         struct btrfs_block_group_cache *cache;
 617         u64 used;
 618         u64 last = max(search_hint, search_start);
 619         u64 group_start = 0;
 620         int full_search = 0;
 621         int factor = 9;
 622         int wrapped = 0;
 623 again:
 624         while (1) {
 625                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 626                 if (!cache)
 627                         break;
 628
 629                 spin_lock(&cache->lock);
 630                 last = cache->key.objectid + cache->key.offset;
 631                 used = btrfs_block_group_used(&cache->item);
 632
 633                 if ((full_search || !cache->ro) &&
 634                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 635                         if (used + cache->pinned + cache->reserved <
 636                             div_factor(cache->key.offset, factor)) {
 637                                 group_start = cache->key.objectid;
 638                                 spin_unlock(&cache->lock);
 639                                 btrfs_put_block_group(cache);
 640                                 goto found;
 641                         }
 642                 }
 643                 spin_unlock(&cache->lock);
 644                 btrfs_put_block_group(cache);
 645                 cond_resched();
 646         }
 647         if (!wrapped) {
 648                 last = search_start;
 649                 wrapped = 1;
 650                 goto again;
 651         }
 652         if (!full_search && factor < 10) {
 653                 last = search_start;
 654                 full_search = 1;
 655                 factor = 10;
 656                 goto again;
 657         }
 658 found:
 659         return group_start;
 660 }
 661
 662 /* simple helper to search for an existing extent at a given offset */
 663 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 664 {
 665         int ret;
 666         struct btrfs_key key;
 667         struct btrfs_path *path;
 668
 669         path = btrfs_alloc_path();
 670         BUG_ON(!path);
 671         key.objectid = start;
 672         key.offset = len;
 673         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 674         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 675                                 0, 0);
 676         btrfs_free_path(path);
 677         return ret;
 678 }
 679
 680 /*
 681  * helper function to lookup reference count and flags of extent.
 682  *
 683  * the head node for delayed ref is used to store the sum of all the
 684  * reference count modifications queued up in the rbtree. the head
 685  * node may also store the extent flags to set. This way you can check
 686  * to see what the reference count and extent flags would be if all of
 687  * the delayed refs are not processed.
 688  */
 689 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 690                              struct btrfs_root *root, u64 bytenr,
 691                              u64 num_bytes, u64 *refs, u64 *flags)
 692 {
 693         struct btrfs_delayed_ref_head *head;
 694         struct btrfs_delayed_ref_root *delayed_refs;
 695         struct btrfs_path *path;
 696         struct btrfs_extent_item *ei;
 697         struct extent_buffer *leaf;
 698         struct btrfs_key key;
 699         u32 item_size;
 700         u64 num_refs;
 701         u64 extent_flags;
 702         int ret;
 703
 704         path = btrfs_alloc_path();
 705         if (!path)
 706                 return -ENOMEM;
 707
 708         key.objectid = bytenr;
 709         key.type = BTRFS_EXTENT_ITEM_KEY;
 710         key.offset = num_bytes;
 711         if (!trans) {
 712                 path->skip_locking = 1;
 713                 path->search_commit_root = 1;
 714         }
 715 again:
 716         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 717                                 &key, path, 0, 0);
 718         if (ret < 0)
 719                 goto out_free;
 720
 721         if (ret == 0) {
 722                 leaf = path->nodes[0];
 723                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 724                 if (item_size >= sizeof(*ei)) {
 725                         ei = btrfs_item_ptr(leaf, path->slots[0],
 726                                             struct btrfs_extent_item);
 727                         num_refs = btrfs_extent_refs(leaf, ei);
 728                         extent_flags = btrfs_extent_flags(leaf, ei);
 729                 } else {
 730 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 731                         struct btrfs_extent_item_v0 *ei0;
 732                         BUG_ON(item_size != sizeof(*ei0));
 733                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 734                                              struct btrfs_extent_item_v0);
 735                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 736                         /* FIXME: this isn't correct for data */
 737                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 738 #else
 739                         BUG();
 740 #endif
 741                 }
 742                 BUG_ON(num_refs == 0);
 743         } else {
 744                 num_refs = 0;
 745                 extent_flags = 0;
 746                 ret = 0;
 747         }
 748
 749         if (!trans)
 750                 goto out;
 751
 752         delayed_refs = &trans->transaction->delayed_refs;
 753         spin_lock(&delayed_refs->lock);
 754         head = btrfs_find_delayed_ref_head(trans, bytenr);
 755         if (head) {
 756                 if (!mutex_trylock(&head->mutex)) {
 757                         atomic_inc(&head->node.refs);
 758                         spin_unlock(&delayed_refs->lock);
 759
 760                         btrfs_release_path(path);
 761
 762                         /*
 763                          * Mutex was contended, block until it's released and try
 764                          * again
 765                          */
 766                         mutex_lock(&head->mutex);
 767                         mutex_unlock(&head->mutex);
 768                         btrfs_put_delayed_ref(&head->node);
 769                         goto again;
 770                 }
 771                 if (head->extent_op && head->extent_op->update_flags)
 772                         extent_flags |= head->extent_op->flags_to_set;
 773                 else
 774                         BUG_ON(num_refs == 0);
 775
 776                 num_refs += head->node.ref_mod;
 777                 mutex_unlock(&head->mutex);
 778         }
 779         spin_unlock(&delayed_refs->lock);
 780 out:
 781         WARN_ON(num_refs == 0);
 782         if (refs)
 783                 *refs = num_refs;
 784         if (flags)
 785                 *flags = extent_flags;
 786 out_free:
 787         btrfs_free_path(path);
 788         return ret;
 789 }
 790
 791 /*
 792  * Back reference rules.  Back refs have three main goals:
 793  *
 794  * 1) differentiate between all holders of references to an extent so that
 795  *    when a reference is dropped we can make sure it was a valid reference
 796  *    before freeing the extent.
 797  *
 798  * 2) Provide enough information to quickly find the holders of an extent
 799  *    if we notice a given block is corrupted or bad.
 800  *
 801  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 802  *    maintenance.  This is actually the same as #2, but with a slightly
 803  *    different use case.
 804  *
 805  * There are two kinds of back refs. The implicit back refs is optimized
 806  * for pointers in non-shared tree blocks. For a given pointer in a block,
 807  * back refs of this kind provide information about the block's owner tree
 808  * and the pointer's key. These information allow us to find the block by
 809  * b-tree searching. The full back refs is for pointers in tree blocks not
 810  * referenced by their owner trees. The location of tree block is recorded
 811  * in the back refs. Actually the full back refs is generic, and can be
 812  * used in all cases the implicit back refs is used. The major shortcoming
 813  * of the full back refs is its overhead. Every time a tree block gets
 814  * COWed, we have to update back refs entry for all pointers in it.
 815  *
 816  * For a newly allocated tree block, we use implicit back refs for
 817  * pointers in it. This means most tree related operations only involve
 818  * implicit back refs. For a tree block created in old transaction, the
 819  * only way to drop a reference to it is COW it. So we can detect the
 820  * event that tree block loses its owner tree's reference and do the
 821  * back refs conversion.
 822  *
 823  * When a tree block is COW'd through a tree, there are four cases:
 824  *
 825  * The reference count of the block is one and the tree is the block's
 826  * owner tree. Nothing to do in this case.
 827  *
 828  * The reference count of the block is one and the tree is not the
 829  * block's owner tree. In this case, full back refs is used for pointers
 830  * in the block. Remove these full back refs, add implicit back refs for
 831  * every pointers in the new block.
 832  *
 833  * The reference count of the block is greater than one and the tree is
 834  * the block's owner tree. In this case, implicit back refs is used for
 835  * pointers in the block. Add full back refs for every pointers in the
 836  * block, increase lower level extents' reference counts. The original
 837  * implicit back refs are entailed to the new block.
 838  *
 839  * The reference count of the block is greater than one and the tree is
 840  * not the block's owner tree. Add implicit back refs for every pointer in
 841  * the new block, increase lower level extents' reference count.
 842  *
 843  * Back Reference Key composing:
 844  *
 845  * The key objectid corresponds to the first byte in the extent,
 846  * The key type is used to differentiate between types of back refs.
 847  * There are different meanings of the key offset for different types
 848  * of back refs.
 849  *
 850  * File extents can be referenced by:
 851  *
 852  * - multiple snapshots, subvolumes, or different generations in one subvol
 853  * - different files inside a single subvolume
 854  * - different offsets inside a file (bookend extents in file.c)
 855  *
 856  * The extent ref structure for the implicit back refs has fields for:
 857  *
 858  * - Objectid of the subvolume root
 859  * - objectid of the file holding the reference
 860  * - original offset in the file
 861  * - how many bookend extents
 862  *
 863  * The key offset for the implicit back refs is hash of the first
 864  * three fields.
 865  *
 866  * The extent ref structure for the full back refs has field for:
 867  *
 868  * - number of pointers in the tree leaf
 869  *
 870  * The key offset for the implicit back refs is the first byte of
 871  * the tree leaf
 872  *
 873  * When a file extent is allocated, The implicit back refs is used.
 874  * the fields are filled in:
 875  *
 876  *     (root_key.objectid, inode objectid, offset in file, 1)
 877  *
 878  * When a file extent is removed file truncation, we find the
 879  * corresponding implicit back refs and check the following fields:
 880  *
 881  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 882  *
 883  * Btree extents can be referenced by:
 884  *
 885  * - Different subvolumes
 886  *
 887  * Both the implicit back refs and the full back refs for tree blocks
 888  * only consist of key. The key offset for the implicit back refs is
 889  * objectid of block's owner tree. The key offset for the full back refs
 890  * is the first byte of parent block.
 891  *
 892  * When implicit back refs is used, information about the lowest key and
 893  * level of the tree block are required. These information are stored in
 894  * tree block info structure.
 895  */
 896
 897 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 898 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 899                                   struct btrfs_root *root,
 900                                   struct btrfs_path *path,
 901                                   u64 owner, u32 extra_size)
 902 {
 903         struct btrfs_extent_item *item;
 904         struct btrfs_extent_item_v0 *ei0;
 905         struct btrfs_extent_ref_v0 *ref0;
 906         struct btrfs_tree_block_info *bi;
 907         struct extent_buffer *leaf;
 908         struct btrfs_key key;
 909         struct btrfs_key found_key;
 910         u32 new_size = sizeof(*item);
 911         u64 refs;
 912         int ret;
 913
 914         leaf = path->nodes[0];
 915         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 916
 917         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 918         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 919                              struct btrfs_extent_item_v0);
 920         refs = btrfs_extent_refs_v0(leaf, ei0);
 921
 922         if (owner == (u64)-1) {
 923                 while (1) {
 924                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 925                                 ret = btrfs_next_leaf(root, path);
 926                                 if (ret < 0)
 927                                         return ret;
 928                                 BUG_ON(ret > 0);
 929                                 leaf = path->nodes[0];
 930                         }
 931                         btrfs_item_key_to_cpu(leaf, &found_key,
 932                                               path->slots[0]);
 933                         BUG_ON(key.objectid != found_key.objectid);
 934                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 935                                 path->slots[0]++;
 936                                 continue;
 937                         }
 938                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 939                                               struct btrfs_extent_ref_v0);
 940                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 941                         break;
 942                 }
 943         }
 944         btrfs_release_path(path);
 945
 946         if (owner < BTRFS_FIRST_FREE_OBJECTID)
 947                 new_size += sizeof(*bi);
 948
 949         new_size -= sizeof(*ei0);
 950         ret = btrfs_search_slot(trans, root, &key, path,
 951                                 new_size + extra_size, 1);
 952         if (ret < 0)
 953                 return ret;
 954         BUG_ON(ret);
 955
 956         ret = btrfs_extend_item(trans, root, path, new_size);
 957
 958         leaf = path->nodes[0];
 959         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 960         btrfs_set_extent_refs(leaf, item, refs);
 961         /* FIXME: get real generation */
 962         btrfs_set_extent_generation(leaf, item, 0);
 963         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 964                 btrfs_set_extent_flags(leaf, item,
 965                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
 966                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
 967                 bi = (struct btrfs_tree_block_info *)(item + 1);
 968                 /* FIXME: get first key of the block */
 969                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
 970                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
 971         } else {
 972                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
 973         }
 974         btrfs_mark_buffer_dirty(leaf);
 975         return 0;
 976 }
 977 #endif
 978
 979 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 980 {
 981         u32 high_crc = ~(u32)0;
 982         u32 low_crc = ~(u32)0;
 983         __le64 lenum;
 984
 985         lenum = cpu_to_le64(root_objectid);
 986         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
 987         lenum = cpu_to_le64(owner);
 988         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 989         lenum = cpu_to_le64(offset);
 990         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
 991
 992         return ((u64)high_crc << 31) ^ (u64)low_crc;
 993 }
 994
 995 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 996                                      struct btrfs_extent_data_ref *ref)
 997 {
 998         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 999                                     btrfs_extent_data_ref_objectid(leaf, ref),
1000                                     btrfs_extent_data_ref_offset(leaf, ref));
1001 }
1002
1003 static int match_extent_data_ref(struct extent_buffer *leaf,
1004                                  struct btrfs_extent_data_ref *ref,
1005                                  u64 root_objectid, u64 owner, u64 offset)
1006 {
1007         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1008             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1009             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1010                 return 0;
1011         return 1;
1012 }
1013
1014 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1015                                            struct btrfs_root *root,
1016                                            struct btrfs_path *path,
1017                                            u64 bytenr, u64 parent,
1018                                            u64 root_objectid,
1019                                            u64 owner, u64 offset)
1020 {
1021         struct btrfs_key key;
1022         struct btrfs_extent_data_ref *ref;
1023         struct extent_buffer *leaf;
1024         u32 nritems;
1025         int ret;
1026         int recow;
1027         int err = -ENOENT;
1028
1029         key.objectid = bytenr;
1030         if (parent) {
1031                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1032                 key.offset = parent;
1033         } else {
1034                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1035                 key.offset = hash_extent_data_ref(root_objectid,
1036                                                   owner, offset);
1037         }
1038 again:
1039         recow = 0;
1040         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1041         if (ret < 0) {
1042                 err = ret;
1043                 goto fail;
1044         }
1045
1046         if (parent) {
1047                 if (!ret)
1048                         return 0;
1049 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1050                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1051                 btrfs_release_path(path);
1052                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1053                 if (ret < 0) {
1054                         err = ret;
1055                         goto fail;
1056                 }
1057                 if (!ret)
1058                         return 0;
1059 #endif
1060                 goto fail;
1061         }
1062
1063         leaf = path->nodes[0];
1064         nritems = btrfs_header_nritems(leaf);
1065         while (1) {
1066                 if (path->slots[0] >= nritems) {
1067                         ret = btrfs_next_leaf(root, path);
1068                         if (ret < 0)
1069                                 err = ret;
1070                         if (ret)
1071                                 goto fail;
1072
1073                         leaf = path->nodes[0];
1074                         nritems = btrfs_header_nritems(leaf);
1075                         recow = 1;
1076                 }
1077
1078                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1079                 if (key.objectid != bytenr ||
1080                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1081                         goto fail;
1082
1083                 ref = btrfs_item_ptr(leaf, path->slots[0],
1084                                      struct btrfs_extent_data_ref);
1085
1086                 if (match_extent_data_ref(leaf, ref, root_objectid,
1087                                           owner, offset)) {
1088                         if (recow) {
1089                                 btrfs_release_path(path);
1090                                 goto again;
1091                         }
1092                         err = 0;
1093                         break;
1094                 }
1095                 path->slots[0]++;
1096         }
1097 fail:
1098         return err;
1099 }
1100
1101 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1102                                            struct btrfs_root *root,
1103                                            struct btrfs_path *path,
1104                                            u64 bytenr, u64 parent,
1105                                            u64 root_objectid, u64 owner,
1106                                            u64 offset, int refs_to_add)
1107 {
1108         struct btrfs_key key;
1109         struct extent_buffer *leaf;
1110         u32 size;
1111         u32 num_refs;
1112         int ret;
1113
1114         key.objectid = bytenr;
1115         if (parent) {
1116                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1117                 key.offset = parent;
1118                 size = sizeof(struct btrfs_shared_data_ref);
1119         } else {
1120                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1121                 key.offset = hash_extent_data_ref(root_objectid,
1122                                                   owner, offset);
1123                 size = sizeof(struct btrfs_extent_data_ref);
1124         }
1125
1126         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1127         if (ret && ret != -EEXIST)
1128                 goto fail;
1129
1130         leaf = path->nodes[0];
1131         if (parent) {
1132                 struct btrfs_shared_data_ref *ref;
1133                 ref = btrfs_item_ptr(leaf, path->slots[0],
1134                                      struct btrfs_shared_data_ref);
1135                 if (ret == 0) {
1136                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1137                 } else {
1138                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1139                         num_refs += refs_to_add;
1140                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1141                 }
1142         } else {
1143                 struct btrfs_extent_data_ref *ref;
1144                 while (ret == -EEXIST) {
1145                         ref = btrfs_item_ptr(leaf, path->slots[0],
1146                                              struct btrfs_extent_data_ref);
1147                         if (match_extent_data_ref(leaf, ref, root_objectid,
1148                                                   owner, offset))
1149                                 break;
1150                         btrfs_release_path(path);
1151                         key.offset++;
1152                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1153                                                       size);
1154                         if (ret && ret != -EEXIST)
1155                                 goto fail;
1156
1157                         leaf = path->nodes[0];
1158                 }
1159                 ref = btrfs_item_ptr(leaf, path->slots[0],
1160                                      struct btrfs_extent_data_ref);
1161                 if (ret == 0) {
1162                         btrfs_set_extent_data_ref_root(leaf, ref,
1163                                                        root_objectid);
1164                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1165                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1166                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1167                 } else {
1168                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1169                         num_refs += refs_to_add;
1170                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1171                 }
1172         }
1173         btrfs_mark_buffer_dirty(leaf);
1174         ret = 0;
1175 fail:
1176         btrfs_release_path(path);
1177         return ret;
1178 }
1179
1180 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1181                                            struct btrfs_root *root,
1182                                            struct btrfs_path *path,
1183                                            int refs_to_drop)
1184 {
1185         struct btrfs_key key;
1186         struct btrfs_extent_data_ref *ref1 = NULL;
1187         struct btrfs_shared_data_ref *ref2 = NULL;
1188         struct extent_buffer *leaf;
1189         u32 num_refs = 0;
1190         int ret = 0;
1191
1192         leaf = path->nodes[0];
1193         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1194
1195         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1196                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1197                                       struct btrfs_extent_data_ref);
1198                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1199         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1200                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1201                                       struct btrfs_shared_data_ref);
1202                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1203 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1204         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1205                 struct btrfs_extent_ref_v0 *ref0;
1206                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1207                                       struct btrfs_extent_ref_v0);
1208                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1209 #endif
1210         } else {
1211                 BUG();
1212         }
1213
1214         BUG_ON(num_refs < refs_to_drop);
1215         num_refs -= refs_to_drop;
1216
1217         if (num_refs == 0) {
1218                 ret = btrfs_del_item(trans, root, path);
1219         } else {
1220                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1221                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1222                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1223                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1224 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1225                 else {
1226                         struct btrfs_extent_ref_v0 *ref0;
1227                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1228                                         struct btrfs_extent_ref_v0);
1229                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1230                 }
1231 #endif
1232                 btrfs_mark_buffer_dirty(leaf);
1233         }
1234         return ret;
1235 }
1236
1237 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1238                                           struct btrfs_path *path,
1239                                           struct btrfs_extent_inline_ref *iref)
1240 {
1241         struct btrfs_key key;
1242         struct extent_buffer *leaf;
1243         struct btrfs_extent_data_ref *ref1;
1244         struct btrfs_shared_data_ref *ref2;
1245         u32 num_refs = 0;
1246
1247         leaf = path->nodes[0];
1248         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1249         if (iref) {
1250                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1251                     BTRFS_EXTENT_DATA_REF_KEY) {
1252                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1253                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1254                 } else {
1255                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1256                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1257                 }
1258         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1259                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1260                                       struct btrfs_extent_data_ref);
1261                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1262         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1263                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1264                                       struct btrfs_shared_data_ref);
1265                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1266 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1267         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1268                 struct btrfs_extent_ref_v0 *ref0;
1269                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1270                                       struct btrfs_extent_ref_v0);
1271                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1272 #endif
1273         } else {
1274                 WARN_ON(1);
1275         }
1276         return num_refs;
1277 }
1278
1279 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1280                                           struct btrfs_root *root,
1281                                           struct btrfs_path *path,
1282                                           u64 bytenr, u64 parent,
1283                                           u64 root_objectid)
1284 {
1285         struct btrfs_key key;
1286         int ret;
1287
1288         key.objectid = bytenr;
1289         if (parent) {
1290                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1291                 key.offset = parent;
1292         } else {
1293                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1294                 key.offset = root_objectid;
1295         }
1296
1297         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1298         if (ret > 0)
1299                 ret = -ENOENT;
1300 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1301         if (ret == -ENOENT && parent) {
1302                 btrfs_release_path(path);
1303                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1304                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1305                 if (ret > 0)
1306                         ret = -ENOENT;
1307         }
1308 #endif
1309         return ret;
1310 }
1311
1312 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1313                                           struct btrfs_root *root,
1314                                           struct btrfs_path *path,
1315                                           u64 bytenr, u64 parent,
1316                                           u64 root_objectid)
1317 {
1318         struct btrfs_key key;
1319         int ret;
1320
1321         key.objectid = bytenr;
1322         if (parent) {
1323                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1324                 key.offset = parent;
1325         } else {
1326                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1327                 key.offset = root_objectid;
1328         }
1329
1330         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1331         btrfs_release_path(path);
1332         return ret;
1333 }
1334
1335 static inline int extent_ref_type(u64 parent, u64 owner)
1336 {
1337         int type;
1338         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1339                 if (parent > 0)
1340                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1341                 else
1342                         type = BTRFS_TREE_BLOCK_REF_KEY;
1343         } else {
1344                 if (parent > 0)
1345                         type = BTRFS_SHARED_DATA_REF_KEY;
1346                 else
1347                         type = BTRFS_EXTENT_DATA_REF_KEY;
1348         }
1349         return type;
1350 }
1351
1352 static int find_next_key(struct btrfs_path *path, int level,
1353                          struct btrfs_key *key)
1354
1355 {
1356         for (; level < BTRFS_MAX_LEVEL; level++) {
1357                 if (!path->nodes[level])
1358                         break;
1359                 if (path->slots[level] + 1 >=
1360                     btrfs_header_nritems(path->nodes[level]))
1361                         continue;
1362                 if (level == 0)
1363                         btrfs_item_key_to_cpu(path->nodes[level], key,
1364                                               path->slots[level] + 1);
1365                 else
1366                         btrfs_node_key_to_cpu(path->nodes[level], key,
1367                                               path->slots[level] + 1);
1368                 return 0;
1369         }
1370         return 1;
1371 }
1372
1373 /*
1374  * look for inline back ref. if back ref is found, *ref_ret is set
1375  * to the address of inline back ref, and 0 is returned.
1376  *
1377  * if back ref isn't found, *ref_ret is set to the address where it
1378  * should be inserted, and -ENOENT is returned.
1379  *
1380  * if insert is true and there are too many inline back refs, the path
1381  * points to the extent item, and -EAGAIN is returned.
1382  *
1383  * NOTE: inline back refs are ordered in the same way that back ref
1384  *       items in the tree are ordered.
1385  */
1386 static noinline_for_stack
1387 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1388                                  struct btrfs_root *root,
1389                                  struct btrfs_path *path,
1390                                  struct btrfs_extent_inline_ref **ref_ret,
1391                                  u64 bytenr, u64 num_bytes,
1392                                  u64 parent, u64 root_objectid,
1393                                  u64 owner, u64 offset, int insert)
1394 {
1395         struct btrfs_key key;
1396         struct extent_buffer *leaf;
1397         struct btrfs_extent_item *ei;
1398         struct btrfs_extent_inline_ref *iref;
1399         u64 flags;
1400         u64 item_size;
1401         unsigned long ptr;
1402         unsigned long end;
1403         int extra_size;
1404         int type;
1405         int want;
1406         int ret;
1407         int err = 0;
1408
1409         key.objectid = bytenr;
1410         key.type = BTRFS_EXTENT_ITEM_KEY;
1411         key.offset = num_bytes;
1412
1413         want = extent_ref_type(parent, owner);
1414         if (insert) {
1415                 extra_size = btrfs_extent_inline_ref_size(want);
1416                 path->keep_locks = 1;
1417         } else
1418                 extra_size = -1;
1419         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1420         if (ret < 0) {
1421                 err = ret;
1422                 goto out;
1423         }
1424         BUG_ON(ret);
1425
1426         leaf = path->nodes[0];
1427         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1428 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1429         if (item_size < sizeof(*ei)) {
1430                 if (!insert) {
1431                         err = -ENOENT;
1432                         goto out;
1433                 }
1434                 ret = convert_extent_item_v0(trans, root, path, owner,
1435                                              extra_size);
1436                 if (ret < 0) {
1437                         err = ret;
1438                         goto out;
1439                 }
1440                 leaf = path->nodes[0];
1441                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1442         }
1443 #endif
1444         BUG_ON(item_size < sizeof(*ei));
1445
1446         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1447         flags = btrfs_extent_flags(leaf, ei);
1448
1449         ptr = (unsigned long)(ei + 1);
1450         end = (unsigned long)ei + item_size;
1451
1452         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1453                 ptr += sizeof(struct btrfs_tree_block_info);
1454                 BUG_ON(ptr > end);
1455         } else {
1456                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1457         }
1458
1459         err = -ENOENT;
1460         while (1) {
1461                 if (ptr >= end) {
1462                         WARN_ON(ptr > end);
1463                         break;
1464                 }
1465                 iref = (struct btrfs_extent_inline_ref *)ptr;
1466                 type = btrfs_extent_inline_ref_type(leaf, iref);
1467                 if (want < type)
1468                         break;
1469                 if (want > type) {
1470                         ptr += btrfs_extent_inline_ref_size(type);
1471                         continue;
1472                 }
1473
1474                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1475                         struct btrfs_extent_data_ref *dref;
1476                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1477                         if (match_extent_data_ref(leaf, dref, root_objectid,
1478                                                   owner, offset)) {
1479                                 err = 0;
1480                                 break;
1481                         }
1482                         if (hash_extent_data_ref_item(leaf, dref) <
1483                             hash_extent_data_ref(root_objectid, owner, offset))
1484                                 break;
1485                 } else {
1486                         u64 ref_offset;
1487                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1488                         if (parent > 0) {
1489                                 if (parent == ref_offset) {
1490                                         err = 0;
1491                                         break;
1492                                 }
1493                                 if (ref_offset < parent)
1494                                         break;
1495                         } else {
1496                                 if (root_objectid == ref_offset) {
1497                                         err = 0;
1498                                         break;
1499                                 }
1500                                 if (ref_offset < root_objectid)
1501                                         break;
1502                         }
1503                 }
1504                 ptr += btrfs_extent_inline_ref_size(type);
1505         }
1506         if (err == -ENOENT && insert) {
1507                 if (item_size + extra_size >=
1508                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1509                         err = -EAGAIN;
1510                         goto out;
1511                 }
1512                 /*
1513                  * To add new inline back ref, we have to make sure
1514                  * there is no corresponding back ref item.
1515                  * For simplicity, we just do not add new inline back
1516                  * ref if there is any kind of item for this block
1517                  */
1518                 if (find_next_key(path, 0, &key) == 0 &&
1519                     key.objectid == bytenr &&
1520                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1521                         err = -EAGAIN;
1522                         goto out;
1523                 }
1524         }
1525         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1526 out:
1527         if (insert) {
1528                 path->keep_locks = 0;
1529                 btrfs_unlock_up_safe(path, 1);
1530         }
1531         return err;
1532 }
1533
1534 /*
1535  * helper to add new inline back ref
1536  */
1537 static noinline_for_stack
1538 int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1539                                 struct btrfs_root *root,
1540                                 struct btrfs_path *path,
1541                                 struct btrfs_extent_inline_ref *iref,
1542                                 u64 parent, u64 root_objectid,
1543                                 u64 owner, u64 offset, int refs_to_add,
1544                                 struct btrfs_delayed_extent_op *extent_op)
1545 {
1546         struct extent_buffer *leaf;
1547         struct btrfs_extent_item *ei;
1548         unsigned long ptr;
1549         unsigned long end;
1550         unsigned long item_offset;
1551         u64 refs;
1552         int size;
1553         int type;
1554         int ret;
1555
1556         leaf = path->nodes[0];
1557         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1558         item_offset = (unsigned long)iref - (unsigned long)ei;
1559
1560         type = extent_ref_type(parent, owner);
1561         size = btrfs_extent_inline_ref_size(type);
1562
1563         ret = btrfs_extend_item(trans, root, path, size);
1564
1565         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1566         refs = btrfs_extent_refs(leaf, ei);
1567         refs += refs_to_add;
1568         btrfs_set_extent_refs(leaf, ei, refs);
1569         if (extent_op)
1570                 __run_delayed_extent_op(extent_op, leaf, ei);
1571
1572         ptr = (unsigned long)ei + item_offset;
1573         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1574         if (ptr < end - size)
1575                 memmove_extent_buffer(leaf, ptr + size, ptr,
1576                                       end - size - ptr);
1577
1578         iref = (struct btrfs_extent_inline_ref *)ptr;
1579         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1580         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1581                 struct btrfs_extent_data_ref *dref;
1582                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1583                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1584                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1585                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1586                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1587         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1588                 struct btrfs_shared_data_ref *sref;
1589                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1590                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1591                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1592         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1593                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1594         } else {
1595                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1596         }
1597         btrfs_mark_buffer_dirty(leaf);
1598         return 0;
1599 }
1600
1601 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1602                                  struct btrfs_root *root,
1603                                  struct btrfs_path *path,
1604                                  struct btrfs_extent_inline_ref **ref_ret,
1605                                  u64 bytenr, u64 num_bytes, u64 parent,
1606                                  u64 root_objectid, u64 owner, u64 offset)
1607 {
1608         int ret;
1609
1610         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1611                                            bytenr, num_bytes, parent,
1612                                            root_objectid, owner, offset, 0);
1613         if (ret != -ENOENT)
1614                 return ret;
1615
1616         btrfs_release_path(path);
1617         *ref_ret = NULL;
1618
1619         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1620                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1621                                             root_objectid);
1622         } else {
1623                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1624                                              root_objectid, owner, offset);
1625         }
1626         return ret;
1627 }
1628
1629 /*
1630  * helper to update/remove inline back ref
1631  */
1632 static noinline_for_stack
1633 int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1634                                  struct btrfs_root *root,
1635                                  struct btrfs_path *path,
1636                                  struct btrfs_extent_inline_ref *iref,
1637                                  int refs_to_mod,
1638                                  struct btrfs_delayed_extent_op *extent_op)
1639 {
1640         struct extent_buffer *leaf;
1641         struct btrfs_extent_item *ei;
1642         struct btrfs_extent_data_ref *dref = NULL;
1643         struct btrfs_shared_data_ref *sref = NULL;
1644         unsigned long ptr;
1645         unsigned long end;
1646         u32 item_size;
1647         int size;
1648         int type;
1649         int ret;
1650         u64 refs;
1651
1652         leaf = path->nodes[0];
1653         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1654         refs = btrfs_extent_refs(leaf, ei);
1655         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1656         refs += refs_to_mod;
1657         btrfs_set_extent_refs(leaf, ei, refs);
1658         if (extent_op)
1659                 __run_delayed_extent_op(extent_op, leaf, ei);
1660
1661         type = btrfs_extent_inline_ref_type(leaf, iref);
1662
1663         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1664                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1665                 refs = btrfs_extent_data_ref_count(leaf, dref);
1666         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1667                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1668                 refs = btrfs_shared_data_ref_count(leaf, sref);
1669         } else {
1670                 refs = 1;
1671                 BUG_ON(refs_to_mod != -1);
1672         }
1673
1674         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1675         refs += refs_to_mod;
1676
1677         if (refs > 0) {
1678                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1679                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1680                 else
1681                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1682         } else {
1683                 size =  btrfs_extent_inline_ref_size(type);
1684                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1685                 ptr = (unsigned long)iref;
1686                 end = (unsigned long)ei + item_size;
1687                 if (ptr + size < end)
1688                         memmove_extent_buffer(leaf, ptr, ptr + size,
1689                                               end - ptr - size);
1690                 item_size -= size;
1691                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1692         }
1693         btrfs_mark_buffer_dirty(leaf);
1694         return 0;
1695 }
1696
1697 static noinline_for_stack
1698 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1699                                  struct btrfs_root *root,
1700                                  struct btrfs_path *path,
1701                                  u64 bytenr, u64 num_bytes, u64 parent,
1702                                  u64 root_objectid, u64 owner,
1703                                  u64 offset, int refs_to_add,
1704                                  struct btrfs_delayed_extent_op *extent_op)
1705 {
1706         struct btrfs_extent_inline_ref *iref;
1707         int ret;
1708
1709         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1710                                            bytenr, num_bytes, parent,
1711                                            root_objectid, owner, offset, 1);
1712         if (ret == 0) {
1713                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1714                 ret = update_inline_extent_backref(trans, root, path, iref,
1715                                                    refs_to_add, extent_op);
1716         } else if (ret == -ENOENT) {
1717                 ret = setup_inline_extent_backref(trans, root, path, iref,
1718                                                   parent, root_objectid,
1719                                                   owner, offset, refs_to_add,
1720                                                   extent_op);
1721         }
1722         return ret;
1723 }
1724
1725 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1726                                  struct btrfs_root *root,
1727                                  struct btrfs_path *path,
1728                                  u64 bytenr, u64 parent, u64 root_objectid,
1729                                  u64 owner, u64 offset, int refs_to_add)
1730 {
1731         int ret;
1732         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1733                 BUG_ON(refs_to_add != 1);
1734                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1735                                             parent, root_objectid);
1736         } else {
1737                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1738                                              parent, root_objectid,
1739                                              owner, offset, refs_to_add);
1740         }
1741         return ret;
1742 }
1743
1744 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1745                                  struct btrfs_root *root,
1746                                  struct btrfs_path *path,
1747                                  struct btrfs_extent_inline_ref *iref,
1748                                  int refs_to_drop, int is_data)
1749 {
1750         int ret;
1751
1752         BUG_ON(!is_data && refs_to_drop != 1);
1753         if (iref) {
1754                 ret = update_inline_extent_backref(trans, root, path, iref,
1755                                                    -refs_to_drop, NULL);
1756         } else if (is_data) {
1757                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1758         } else {
1759                 ret = btrfs_del_item(trans, root, path);
1760         }
1761         return ret;
1762 }
1763
1764 static int btrfs_issue_discard(struct block_device *bdev,
1765                                 u64 start, u64 len)
1766 {
1767         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1768 }
1769
1770 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1771                                 u64 num_bytes, u64 *actual_bytes)
1772 {
1773         int ret;
1774         u64 discarded_bytes = 0;
1775         struct btrfs_multi_bio *multi = NULL;
1776
1777
1778         /* Tell the block device(s) that the sectors can be discarded */
1779         ret = btrfs_map_block(&root->fs_info->mapping_tree, REQ_DISCARD,
1780                               bytenr, &num_bytes, &multi, 0);
1781         if (!ret) {
1782                 struct btrfs_bio_stripe *stripe = multi->stripes;
1783                 int i;
1784
1785
1786                 for (i = 0; i < multi->num_stripes; i++, stripe++) {
1787                         ret = btrfs_issue_discard(stripe->dev->bdev,
1788                                                   stripe->physical,
1789                                                   stripe->length);
1790                         if (!ret)
1791                                 discarded_bytes += stripe->length;
1792                         else if (ret != -EOPNOTSUPP)
1793                                 break;
1794                 }
1795                 kfree(multi);
1796         }
1797         if (discarded_bytes && ret == -EOPNOTSUPP)
1798                 ret = 0;
1799
1800         if (actual_bytes)
1801                 *actual_bytes = discarded_bytes;
1802
1803
1804         return ret;
1805 }
1806
1807 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1808                          struct btrfs_root *root,
1809                          u64 bytenr, u64 num_bytes, u64 parent,
1810                          u64 root_objectid, u64 owner, u64 offset)
1811 {
1812         int ret;
1813         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1814                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1815
1816         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1817                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
1818                                         parent, root_objectid, (int)owner,
1819                                         BTRFS_ADD_DELAYED_REF, NULL);
1820         } else {
1821                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
1822                                         parent, root_objectid, owner, offset,
1823                                         BTRFS_ADD_DELAYED_REF, NULL);
1824         }
1825         return ret;
1826 }
1827
1828 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1829                                   struct btrfs_root *root,
1830                                   u64 bytenr, u64 num_bytes,
1831                                   u64 parent, u64 root_objectid,
1832                                   u64 owner, u64 offset, int refs_to_add,
1833                                   struct btrfs_delayed_extent_op *extent_op)
1834 {
1835         struct btrfs_path *path;
1836         struct extent_buffer *leaf;
1837         struct btrfs_extent_item *item;
1838         u64 refs;
1839         int ret;
1840         int err = 0;
1841
1842         path = btrfs_alloc_path();
1843         if (!path)
1844                 return -ENOMEM;
1845
1846         path->reada = 1;
1847         path->leave_spinning = 1;
1848         /* this will setup the path even if it fails to insert the back ref */
1849         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1850                                            path, bytenr, num_bytes, parent,
1851                                            root_objectid, owner, offset,
1852                                            refs_to_add, extent_op);
1853         if (ret == 0)
1854                 goto out;
1855
1856         if (ret != -EAGAIN) {
1857                 err = ret;
1858                 goto out;
1859         }
1860
1861         leaf = path->nodes[0];
1862         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1863         refs = btrfs_extent_refs(leaf, item);
1864         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1865         if (extent_op)
1866                 __run_delayed_extent_op(extent_op, leaf, item);
1867
1868         btrfs_mark_buffer_dirty(leaf);
1869         btrfs_release_path(path);
1870
1871         path->reada = 1;
1872         path->leave_spinning = 1;
1873
1874         /* now insert the actual backref */
1875         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1876                                     path, bytenr, parent, root_objectid,
1877                                     owner, offset, refs_to_add);
1878         BUG_ON(ret);
1879 out:
1880         btrfs_free_path(path);
1881         return err;
1882 }
1883
1884 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1885                                 struct btrfs_root *root,
1886                                 struct btrfs_delayed_ref_node *node,
1887                                 struct btrfs_delayed_extent_op *extent_op,
1888                                 int insert_reserved)
1889 {
1890         int ret = 0;
1891         struct btrfs_delayed_data_ref *ref;
1892         struct btrfs_key ins;
1893         u64 parent = 0;
1894         u64 ref_root = 0;
1895         u64 flags = 0;
1896
1897         ins.objectid = node->bytenr;
1898         ins.offset = node->num_bytes;
1899         ins.type = BTRFS_EXTENT_ITEM_KEY;
1900
1901         ref = btrfs_delayed_node_to_data_ref(node);
1902         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1903                 parent = ref->parent;
1904         else
1905                 ref_root = ref->root;
1906
1907         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1908                 if (extent_op) {
1909                         BUG_ON(extent_op->update_key);
1910                         flags |= extent_op->flags_to_set;
1911                 }
1912                 ret = alloc_reserved_file_extent(trans, root,
1913                                                  parent, ref_root, flags,
1914                                                  ref->objectid, ref->offset,
1915                                                  &ins, node->ref_mod);
1916         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1917                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1918                                              node->num_bytes, parent,
1919                                              ref_root, ref->objectid,
1920                                              ref->offset, node->ref_mod,
1921                                              extent_op);
1922         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1923                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1924                                           node->num_bytes, parent,
1925                                           ref_root, ref->objectid,
1926                                           ref->offset, node->ref_mod,
1927                                           extent_op);
1928         } else {
1929                 BUG();
1930         }
1931         return ret;
1932 }
1933
1934 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1935                                     struct extent_buffer *leaf,
1936                                     struct btrfs_extent_item *ei)
1937 {
1938         u64 flags = btrfs_extent_flags(leaf, ei);
1939         if (extent_op->update_flags) {
1940                 flags |= extent_op->flags_to_set;
1941                 btrfs_set_extent_flags(leaf, ei, flags);
1942         }
1943
1944         if (extent_op->update_key) {
1945                 struct btrfs_tree_block_info *bi;
1946                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1947                 bi = (struct btrfs_tree_block_info *)(ei + 1);
1948                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1949         }
1950 }
1951
1952 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1953                                  struct btrfs_root *root,
1954                                  struct btrfs_delayed_ref_node *node,
1955                                  struct btrfs_delayed_extent_op *extent_op)
1956 {
1957         struct btrfs_key key;
1958         struct btrfs_path *path;
1959         struct btrfs_extent_item *ei;
1960         struct extent_buffer *leaf;
1961         u32 item_size;
1962         int ret;
1963         int err = 0;
1964
1965         path = btrfs_alloc_path();
1966         if (!path)
1967                 return -ENOMEM;
1968
1969         key.objectid = node->bytenr;
1970         key.type = BTRFS_EXTENT_ITEM_KEY;
1971         key.offset = node->num_bytes;
1972
1973         path->reada = 1;
1974         path->leave_spinning = 1;
1975         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
1976                                 path, 0, 1);
1977         if (ret < 0) {
1978                 err = ret;
1979                 goto out;
1980         }
1981         if (ret > 0) {
1982                 err = -EIO;
1983                 goto out;
1984         }
1985
1986         leaf = path->nodes[0];
1987         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1988 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1989         if (item_size < sizeof(*ei)) {
1990                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
1991                                              path, (u64)-1, 0);
1992                 if (ret < 0) {
1993                         err = ret;
1994                         goto out;
1995                 }
1996                 leaf = path->nodes[0];
1997                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1998         }
1999 #endif
2000         BUG_ON(item_size < sizeof(*ei));
2001         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2002         __run_delayed_extent_op(extent_op, leaf, ei);
2003
2004         btrfs_mark_buffer_dirty(leaf);
2005 out:
2006         btrfs_free_path(path);
2007         return err;
2008 }
2009
2010 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2011                                 struct btrfs_root *root,
2012                                 struct btrfs_delayed_ref_node *node,
2013                                 struct btrfs_delayed_extent_op *extent_op,
2014                                 int insert_reserved)
2015 {
2016         int ret = 0;
2017         struct btrfs_delayed_tree_ref *ref;
2018         struct btrfs_key ins;
2019         u64 parent = 0;
2020         u64 ref_root = 0;
2021
2022         ins.objectid = node->bytenr;
2023         ins.offset = node->num_bytes;
2024         ins.type = BTRFS_EXTENT_ITEM_KEY;
2025
2026         ref = btrfs_delayed_node_to_tree_ref(node);
2027         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2028                 parent = ref->parent;
2029         else
2030                 ref_root = ref->root;
2031
2032         BUG_ON(node->ref_mod != 1);
2033         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2034                 BUG_ON(!extent_op || !extent_op->update_flags ||
2035                        !extent_op->update_key);
2036                 ret = alloc_reserved_tree_block(trans, root,
2037                                                 parent, ref_root,
2038                                                 extent_op->flags_to_set,
2039                                                 &extent_op->key,
2040                                                 ref->level, &ins);
2041         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2042                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2043                                              node->num_bytes, parent, ref_root,
2044                                              ref->level, 0, 1, extent_op);
2045         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2046                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2047                                           node->num_bytes, parent, ref_root,
2048                                           ref->level, 0, 1, extent_op);
2049         } else {
2050                 BUG();
2051         }
2052         return ret;
2053 }
2054
2055 /* helper function to actually process a single delayed ref entry */
2056 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2057                                struct btrfs_root *root,
2058                                struct btrfs_delayed_ref_node *node,
2059                                struct btrfs_delayed_extent_op *extent_op,
2060                                int insert_reserved)
2061 {
2062         int ret;
2063         if (btrfs_delayed_ref_is_head(node)) {
2064                 struct btrfs_delayed_ref_head *head;
2065                 /*
2066                  * we've hit the end of the chain and we were supposed
2067                  * to insert this extent into the tree.  But, it got
2068                  * deleted before we ever needed to insert it, so all
2069                  * we have to do is clean up the accounting
2070                  */
2071                 BUG_ON(extent_op);
2072                 head = btrfs_delayed_node_to_head(node);
2073                 if (insert_reserved) {
2074                         btrfs_pin_extent(root, node->bytenr,
2075                                          node->num_bytes, 1);
2076                         if (head->is_data) {
2077                                 ret = btrfs_del_csums(trans, root,
2078                                                       node->bytenr,
2079                                                       node->num_bytes);
2080                                 BUG_ON(ret);
2081                         }
2082                 }
2083                 mutex_unlock(&head->mutex);
2084                 return 0;
2085         }
2086
2087         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2088             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2089                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2090                                            insert_reserved);
2091         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2092                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2093                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2094                                            insert_reserved);
2095         else
2096                 BUG();
2097         return ret;
2098 }
2099
2100 static noinline struct btrfs_delayed_ref_node *
2101 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2102 {
2103         struct rb_node *node;
2104         struct btrfs_delayed_ref_node *ref;
2105         int action = BTRFS_ADD_DELAYED_REF;
2106 again:
2107         /*
2108          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2109          * this prevents ref count from going down to zero when
2110          * there still are pending delayed ref.
2111          */
2112         node = rb_prev(&head->node.rb_node);
2113         while (1) {
2114                 if (!node)
2115                         break;
2116                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2117                                 rb_node);
2118                 if (ref->bytenr != head->node.bytenr)
2119                         break;
2120                 if (ref->action == action)
2121                         return ref;
2122                 node = rb_prev(node);
2123         }
2124         if (action == BTRFS_ADD_DELAYED_REF) {
2125                 action = BTRFS_DROP_DELAYED_REF;
2126                 goto again;
2127         }
2128         return NULL;
2129 }
2130
2131 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2132                                        struct btrfs_root *root,
2133                                        struct list_head *cluster)
2134 {
2135         struct btrfs_delayed_ref_root *delayed_refs;
2136         struct btrfs_delayed_ref_node *ref;
2137         struct btrfs_delayed_ref_head *locked_ref = NULL;
2138         struct btrfs_delayed_extent_op *extent_op;
2139         int ret;
2140         int count = 0;
2141         int must_insert_reserved = 0;
2142
2143         delayed_refs = &trans->transaction->delayed_refs;
2144         while (1) {
2145                 if (!locked_ref) {
2146                         /* pick a new head ref from the cluster list */
2147                         if (list_empty(cluster))
2148                                 break;
2149
2150                         locked_ref = list_entry(cluster->next,
2151                                      struct btrfs_delayed_ref_head, cluster);
2152
2153                         /* grab the lock that says we are going to process
2154                          * all the refs for this head */
2155                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2156
2157                         /*
2158                          * we may have dropped the spin lock to get the head
2159                          * mutex lock, and that might have given someone else
2160                          * time to free the head.  If that's true, it has been
2161                          * removed from our list and we can move on.
2162                          */
2163                         if (ret == -EAGAIN) {
2164                                 locked_ref = NULL;
2165                                 count++;
2166                                 continue;
2167                         }
2168                 }
2169
2170                 /*
2171                  * record the must insert reserved flag before we
2172                  * drop the spin lock.
2173                  */
2174                 must_insert_reserved = locked_ref->must_insert_reserved;
2175                 locked_ref->must_insert_reserved = 0;
2176
2177                 extent_op = locked_ref->extent_op;
2178                 locked_ref->extent_op = NULL;
2179
2180                 /*
2181                  * locked_ref is the head node, so we have to go one
2182                  * node back for any delayed ref updates
2183                  */
2184                 ref = select_delayed_ref(locked_ref);
2185                 if (!ref) {
2186                         /* All delayed refs have been processed, Go ahead
2187                          * and send the head node to run_one_delayed_ref,
2188                          * so that any accounting fixes can happen
2189                          */
2190                         ref = &locked_ref->node;
2191
2192                         if (extent_op && must_insert_reserved) {
2193                                 kfree(extent_op);
2194                                 extent_op = NULL;
2195                         }
2196
2197                         if (extent_op) {
2198                                 spin_unlock(&delayed_refs->lock);
2199
2200                                 ret = run_delayed_extent_op(trans, root,
2201                                                             ref, extent_op);
2202                                 BUG_ON(ret);
2203                                 kfree(extent_op);
2204
2205                                 cond_resched();
2206                                 spin_lock(&delayed_refs->lock);
2207                                 continue;
2208                         }
2209
2210                         list_del_init(&locked_ref->cluster);
2211                         locked_ref = NULL;
2212                 }
2213
2214                 ref->in_tree = 0;
2215                 rb_erase(&ref->rb_node, &delayed_refs->root);
2216                 delayed_refs->num_entries--;
2217
2218                 spin_unlock(&delayed_refs->lock);
2219
2220                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2221                                           must_insert_reserved);
2222                 BUG_ON(ret);
2223
2224                 btrfs_put_delayed_ref(ref);
2225                 kfree(extent_op);
2226                 count++;
2227
2228                 cond_resched();
2229                 spin_lock(&delayed_refs->lock);
2230         }
2231         return count;
2232 }
2233
2234 /*
2235  * this starts processing the delayed reference count updates and
2236  * extent insertions we have queued up so far.  count can be
2237  * 0, which means to process everything in the tree at the start
2238  * of the run (but not newly added entries), or it can be some target
2239  * number you'd like to process.
2240  */
2241 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2242                            struct btrfs_root *root, unsigned long count)
2243 {
2244         struct rb_node *node;
2245         struct btrfs_delayed_ref_root *delayed_refs;
2246         struct btrfs_delayed_ref_node *ref;
2247         struct list_head cluster;
2248         int ret;
2249         int run_all = count == (unsigned long)-1;
2250         int run_most = 0;
2251
2252         if (root == root->fs_info->extent_root)
2253                 root = root->fs_info->tree_root;
2254
2255         delayed_refs = &trans->transaction->delayed_refs;
2256         INIT_LIST_HEAD(&cluster);
2257 again:
2258         spin_lock(&delayed_refs->lock);
2259         if (count == 0) {
2260                 count = delayed_refs->num_entries * 2;
2261                 run_most = 1;
2262         }
2263         while (1) {
2264                 if (!(run_all || run_most) &&
2265                     delayed_refs->num_heads_ready < 64)
2266                         break;
2267
2268                 /*
2269                  * go find something we can process in the rbtree.  We start at
2270                  * the beginning of the tree, and then build a cluster
2271                  * of refs to process starting at the first one we are able to
2272                  * lock
2273                  */
2274                 ret = btrfs_find_ref_cluster(trans, &cluster,
2275                                              delayed_refs->run_delayed_start);
2276                 if (ret)
2277                         break;
2278
2279                 ret = run_clustered_refs(trans, root, &cluster);
2280                 BUG_ON(ret < 0);
2281
2282                 count -= min_t(unsigned long, ret, count);
2283
2284                 if (count == 0)
2285                         break;
2286         }
2287
2288         if (run_all) {
2289                 node = rb_first(&delayed_refs->root);
2290                 if (!node)
2291                         goto out;
2292                 count = (unsigned long)-1;
2293
2294                 while (node) {
2295                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2296                                        rb_node);
2297                         if (btrfs_delayed_ref_is_head(ref)) {
2298                                 struct btrfs_delayed_ref_head *head;
2299
2300                                 head = btrfs_delayed_node_to_head(ref);
2301                                 atomic_inc(&ref->refs);
2302
2303                                 spin_unlock(&delayed_refs->lock);
2304                                 /*
2305                                  * Mutex was contended, block until it's
2306                                  * released and try again
2307                                  */
2308                                 mutex_lock(&head->mutex);
2309                                 mutex_unlock(&head->mutex);
2310
2311                                 btrfs_put_delayed_ref(ref);
2312                                 cond_resched();
2313                                 goto again;
2314                         }
2315                         node = rb_next(node);
2316                 }
2317                 spin_unlock(&delayed_refs->lock);
2318                 schedule_timeout(1);
2319                 goto again;
2320         }
2321 out:
2322         spin_unlock(&delayed_refs->lock);
2323         return 0;
2324 }
2325
2326 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2327                                 struct btrfs_root *root,
2328                                 u64 bytenr, u64 num_bytes, u64 flags,
2329                                 int is_data)
2330 {
2331         struct btrfs_delayed_extent_op *extent_op;
2332         int ret;
2333
2334         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2335         if (!extent_op)
2336                 return -ENOMEM;
2337
2338         extent_op->flags_to_set = flags;
2339         extent_op->update_flags = 1;
2340         extent_op->update_key = 0;
2341         extent_op->is_data = is_data ? 1 : 0;
2342
2343         ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
2344         if (ret)
2345                 kfree(extent_op);
2346         return ret;
2347 }
2348
2349 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2350                                       struct btrfs_root *root,
2351                                       struct btrfs_path *path,
2352                                       u64 objectid, u64 offset, u64 bytenr)
2353 {
2354         struct btrfs_delayed_ref_head *head;
2355         struct btrfs_delayed_ref_node *ref;
2356         struct btrfs_delayed_data_ref *data_ref;
2357         struct btrfs_delayed_ref_root *delayed_refs;
2358         struct rb_node *node;
2359         int ret = 0;
2360
2361         ret = -ENOENT;
2362         delayed_refs = &trans->transaction->delayed_refs;
2363         spin_lock(&delayed_refs->lock);
2364         head = btrfs_find_delayed_ref_head(trans, bytenr);
2365         if (!head)
2366                 goto out;
2367
2368         if (!mutex_trylock(&head->mutex)) {
2369                 atomic_inc(&head->node.refs);
2370                 spin_unlock(&delayed_refs->lock);
2371
2372                 btrfs_release_path(path);
2373
2374                 /*
2375                  * Mutex was contended, block until it's released and let
2376                  * caller try again
2377                  */
2378                 mutex_lock(&head->mutex);
2379                 mutex_unlock(&head->mutex);
2380                 btrfs_put_delayed_ref(&head->node);
2381                 return -EAGAIN;
2382         }
2383
2384         node = rb_prev(&head->node.rb_node);
2385         if (!node)
2386                 goto out_unlock;
2387
2388         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2389
2390         if (ref->bytenr != bytenr)
2391                 goto out_unlock;
2392
2393         ret = 1;
2394         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2395                 goto out_unlock;
2396
2397         data_ref = btrfs_delayed_node_to_data_ref(ref);
2398
2399         node = rb_prev(node);
2400         if (node) {
2401                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2402                 if (ref->bytenr == bytenr)
2403                         goto out_unlock;
2404         }
2405
2406         if (data_ref->root != root->root_key.objectid ||
2407             data_ref->objectid != objectid || data_ref->offset != offset)
2408                 goto out_unlock;
2409
2410         ret = 0;
2411 out_unlock:
2412         mutex_unlock(&head->mutex);
2413 out:
2414         spin_unlock(&delayed_refs->lock);
2415         return ret;
2416 }
2417
2418 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2419                                         struct btrfs_root *root,
2420                                         struct btrfs_path *path,
2421                                         u64 objectid, u64 offset, u64 bytenr)
2422 {
2423         struct btrfs_root *extent_root = root->fs_info->extent_root;
2424         struct extent_buffer *leaf;
2425         struct btrfs_extent_data_ref *ref;
2426         struct btrfs_extent_inline_ref *iref;
2427         struct btrfs_extent_item *ei;
2428         struct btrfs_key key;
2429         u32 item_size;
2430         int ret;
2431
2432         key.objectid = bytenr;
2433         key.offset = (u64)-1;
2434         key.type = BTRFS_EXTENT_ITEM_KEY;
2435
2436         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2437         if (ret < 0)
2438                 goto out;
2439         BUG_ON(ret == 0);
2440
2441         ret = -ENOENT;
2442         if (path->slots[0] == 0)
2443                 goto out;
2444
2445         path->slots[0]--;
2446         leaf = path->nodes[0];
2447         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2448
2449         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2450                 goto out;
2451
2452         ret = 1;
2453         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2454 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2455         if (item_size < sizeof(*ei)) {
2456                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2457                 goto out;
2458         }
2459 #endif
2460         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2461
2462         if (item_size != sizeof(*ei) +
2463             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2464                 goto out;
2465
2466         if (btrfs_extent_generation(leaf, ei) <=
2467             btrfs_root_last_snapshot(&root->root_item))
2468                 goto out;
2469
2470         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2471         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2472             BTRFS_EXTENT_DATA_REF_KEY)
2473                 goto out;
2474
2475         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2476         if (btrfs_extent_refs(leaf, ei) !=
2477             btrfs_extent_data_ref_count(leaf, ref) ||
2478             btrfs_extent_data_ref_root(leaf, ref) !=
2479             root->root_key.objectid ||
2480             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2481             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2482                 goto out;
2483
2484         ret = 0;
2485 out:
2486         return ret;
2487 }
2488
2489 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2490                           struct btrfs_root *root,
2491                           u64 objectid, u64 offset, u64 bytenr)
2492 {
2493         struct btrfs_path *path;
2494         int ret;
2495         int ret2;
2496
2497         path = btrfs_alloc_path();
2498         if (!path)
2499                 return -ENOENT;
2500
2501         do {
2502                 ret = check_committed_ref(trans, root, path, objectid,
2503                                           offset, bytenr);
2504                 if (ret && ret != -ENOENT)
2505                         goto out;
2506
2507                 ret2 = check_delayed_ref(trans, root, path, objectid,
2508                                          offset, bytenr);
2509         } while (ret2 == -EAGAIN);
2510
2511         if (ret2 && ret2 != -ENOENT) {
2512                 ret = ret2;
2513                 goto out;
2514         }
2515
2516         if (ret != -ENOENT || ret2 != -ENOENT)
2517                 ret = 0;
2518 out:
2519         btrfs_free_path(path);
2520         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2521                 WARN_ON(ret > 0);
2522         return ret;
2523 }
2524
2525 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2526                            struct btrfs_root *root,
2527                            struct extent_buffer *buf,
2528                            int full_backref, int inc)
2529 {
2530         u64 bytenr;
2531         u64 num_bytes;
2532         u64 parent;
2533         u64 ref_root;
2534         u32 nritems;
2535         struct btrfs_key key;
2536         struct btrfs_file_extent_item *fi;
2537         int i;
2538         int level;
2539         int ret = 0;
2540         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2541                             u64, u64, u64, u64, u64, u64);
2542
2543         ref_root = btrfs_header_owner(buf);
2544         nritems = btrfs_header_nritems(buf);
2545         level = btrfs_header_level(buf);
2546
2547         if (!root->ref_cows && level == 0)
2548                 return 0;
2549
2550         if (inc)
2551                 process_func = btrfs_inc_extent_ref;
2552         else
2553                 process_func = btrfs_free_extent;
2554
2555         if (full_backref)
2556                 parent = buf->start;
2557         else
2558                 parent = 0;
2559
2560         for (i = 0; i < nritems; i++) {
2561                 if (level == 0) {
2562                         btrfs_item_key_to_cpu(buf, &key, i);
2563                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2564                                 continue;
2565                         fi = btrfs_item_ptr(buf, i,
2566                                             struct btrfs_file_extent_item);
2567                         if (btrfs_file_extent_type(buf, fi) ==
2568                             BTRFS_FILE_EXTENT_INLINE)
2569                                 continue;
2570                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2571                         if (bytenr == 0)
2572                                 continue;
2573
2574                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2575                         key.offset -= btrfs_file_extent_offset(buf, fi);
2576                         ret = process_func(trans, root, bytenr, num_bytes,
2577                                            parent, ref_root, key.objectid,
2578                                            key.offset);
2579                         if (ret)
2580                                 goto fail;
2581                 } else {
2582                         bytenr = btrfs_node_blockptr(buf, i);
2583                         num_bytes = btrfs_level_size(root, level - 1);
2584                         ret = process_func(trans, root, bytenr, num_bytes,
2585                                            parent, ref_root, level - 1, 0);
2586                         if (ret)
2587                                 goto fail;
2588                 }
2589         }
2590         return 0;
2591 fail:
2592         BUG();
2593         return ret;
2594 }
2595
2596 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2597                   struct extent_buffer *buf, int full_backref)
2598 {
2599         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2600 }
2601
2602 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2603                   struct extent_buffer *buf, int full_backref)
2604 {
2605         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2606 }
2607
2608 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2609                                  struct btrfs_root *root,
2610                                  struct btrfs_path *path,
2611                                  struct btrfs_block_group_cache *cache)
2612 {
2613         int ret;
2614         struct btrfs_root *extent_root = root->fs_info->extent_root;
2615         unsigned long bi;
2616         struct extent_buffer *leaf;
2617
2618         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2619         if (ret < 0)
2620                 goto fail;
2621         BUG_ON(ret);
2622
2623         leaf = path->nodes[0];
2624         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2625         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2626         btrfs_mark_buffer_dirty(leaf);
2627         btrfs_release_path(path);
2628 fail:
2629         if (ret)
2630                 return ret;
2631         return 0;
2632
2633 }
2634
2635 static struct btrfs_block_group_cache *
2636 next_block_group(struct btrfs_root *root,
2637                  struct btrfs_block_group_cache *cache)
2638 {
2639         struct rb_node *node;
2640         spin_lock(&root->fs_info->block_group_cache_lock);
2641         node = rb_next(&cache->cache_node);
2642         btrfs_put_block_group(cache);
2643         if (node) {
2644                 cache = rb_entry(node, struct btrfs_block_group_cache,
2645                                  cache_node);
2646                 btrfs_get_block_group(cache);
2647         } else
2648                 cache = NULL;
2649         spin_unlock(&root->fs_info->block_group_cache_lock);
2650         return cache;
2651 }
2652
2653 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2654                             struct btrfs_trans_handle *trans,
2655                             struct btrfs_path *path)
2656 {
2657         struct btrfs_root *root = block_group->fs_info->tree_root;
2658         struct inode *inode = NULL;
2659         u64 alloc_hint = 0;
2660         int dcs = BTRFS_DC_ERROR;
2661         int num_pages = 0;
2662         int retries = 0;
2663         int ret = 0;
2664
2665         /*
2666          * If this block group is smaller than 100 megs don't bother caching the
2667          * block group.
2668          */
2669         if (block_group->key.offset < (100 * 1024 * 1024)) {
2670                 spin_lock(&block_group->lock);
2671                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2672                 spin_unlock(&block_group->lock);
2673                 return 0;
2674         }
2675
2676 again:
2677         inode = lookup_free_space_inode(root, block_group, path);
2678         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2679                 ret = PTR_ERR(inode);
2680                 btrfs_release_path(path);
2681                 goto out;
2682         }
2683
2684         if (IS_ERR(inode)) {
2685                 BUG_ON(retries);
2686                 retries++;
2687
2688                 if (block_group->ro)
2689                         goto out_free;
2690
2691                 ret = create_free_space_inode(root, trans, block_group, path);
2692                 if (ret)
2693                         goto out_free;
2694                 goto again;
2695         }
2696
2697         /*
2698          * We want to set the generation to 0, that way if anything goes wrong
2699          * from here on out we know not to trust this cache when we load up next
2700          * time.
2701          */
2702         BTRFS_I(inode)->generation = 0;
2703         ret = btrfs_update_inode(trans, root, inode);
2704         WARN_ON(ret);
2705
2706         if (i_size_read(inode) > 0) {
2707                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2708                                                       inode);
2709                 if (ret)
2710                         goto out_put;
2711         }
2712
2713         spin_lock(&block_group->lock);
2714         if (block_group->cached != BTRFS_CACHE_FINISHED) {
2715                 /* We're not cached, don't bother trying to write stuff out */
2716                 dcs = BTRFS_DC_WRITTEN;
2717                 spin_unlock(&block_group->lock);
2718                 goto out_put;
2719         }
2720         spin_unlock(&block_group->lock);
2721
2722         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2723         if (!num_pages)
2724                 num_pages = 1;
2725
2726         /*
2727          * Just to make absolutely sure we have enough space, we're going to
2728          * preallocate 12 pages worth of space for each block group.  In
2729          * practice we ought to use at most 8, but we need extra space so we can
2730          * add our header and have a terminator between the extents and the
2731          * bitmaps.
2732          */
2733         num_pages *= 16;
2734         num_pages *= PAGE_CACHE_SIZE;
2735
2736         ret = btrfs_check_data_free_space(inode, num_pages);
2737         if (ret)
2738                 goto out_put;
2739
2740         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2741                                               num_pages, num_pages,
2742                                               &alloc_hint);
2743         if (!ret)
2744                 dcs = BTRFS_DC_SETUP;
2745         btrfs_free_reserved_data_space(inode, num_pages);
2746 out_put:
2747         iput(inode);
2748 out_free:
2749         btrfs_release_path(path);
2750 out:
2751         spin_lock(&block_group->lock);
2752         block_group->disk_cache_state = dcs;
2753         spin_unlock(&block_group->lock);
2754
2755         return ret;
2756 }
2757
2758 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2759                                    struct btrfs_root *root)
2760 {
2761         struct btrfs_block_group_cache *cache;
2762         int err = 0;
2763         struct btrfs_path *path;
2764         u64 last = 0;
2765
2766         path = btrfs_alloc_path();
2767         if (!path)
2768                 return -ENOMEM;
2769
2770 again:
2771         while (1) {
2772                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2773                 while (cache) {
2774                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2775                                 break;
2776                         cache = next_block_group(root, cache);
2777                 }
2778                 if (!cache) {
2779                         if (last == 0)
2780                                 break;
2781                         last = 0;
2782                         continue;
2783                 }
2784                 err = cache_save_setup(cache, trans, path);
2785                 last = cache->key.objectid + cache->key.offset;
2786                 btrfs_put_block_group(cache);
2787         }
2788
2789         while (1) {
2790                 if (last == 0) {
2791                         err = btrfs_run_delayed_refs(trans, root,
2792                                                      (unsigned long)-1);
2793                         BUG_ON(err);
2794                 }
2795
2796                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2797                 while (cache) {
2798                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
2799                                 btrfs_put_block_group(cache);
2800                                 goto again;
2801                         }
2802
2803                         if (cache->dirty)
2804                                 break;
2805                         cache = next_block_group(root, cache);
2806                 }
2807                 if (!cache) {
2808                         if (last == 0)
2809                                 break;
2810                         last = 0;
2811                         continue;
2812                 }
2813
2814                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
2815                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
2816                 cache->dirty = 0;
2817                 last = cache->key.objectid + cache->key.offset;
2818
2819                 err = write_one_cache_group(trans, root, path, cache);
2820                 BUG_ON(err);
2821                 btrfs_put_block_group(cache);
2822         }
2823
2824         while (1) {
2825                 /*
2826                  * I don't think this is needed since we're just marking our
2827                  * preallocated extent as written, but just in case it can't
2828                  * hurt.
2829                  */
2830                 if (last == 0) {
2831                         err = btrfs_run_delayed_refs(trans, root,
2832                                                      (unsigned long)-1);
2833                         BUG_ON(err);
2834                 }
2835
2836                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2837                 while (cache) {
2838                         /*
2839                          * Really this shouldn't happen, but it could if we
2840                          * couldn't write the entire preallocated extent and
2841                          * splitting the extent resulted in a new block.
2842                          */
2843                         if (cache->dirty) {
2844                                 btrfs_put_block_group(cache);
2845                                 goto again;
2846                         }
2847                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2848                                 break;
2849                         cache = next_block_group(root, cache);
2850                 }
2851                 if (!cache) {
2852                         if (last == 0)
2853                                 break;
2854                         last = 0;
2855                         continue;
2856                 }
2857
2858                 btrfs_write_out_cache(root, trans, cache, path);
2859
2860                 /*
2861                  * If we didn't have an error then the cache state is still
2862                  * NEED_WRITE, so we can set it to WRITTEN.
2863                  */
2864                 if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2865                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
2866                 last = cache->key.objectid + cache->key.offset;
2867                 btrfs_put_block_group(cache);
2868         }
2869
2870         btrfs_free_path(path);
2871         return 0;
2872 }
2873
2874 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
2875 {
2876         struct btrfs_block_group_cache *block_group;
2877         int readonly = 0;
2878
2879         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
2880         if (!block_group || block_group->ro)
2881                 readonly = 1;
2882         if (block_group)
2883                 btrfs_put_block_group(block_group);
2884         return readonly;
2885 }
2886
2887 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
2888                              u64 total_bytes, u64 bytes_used,
2889                              struct btrfs_space_info **space_info)
2890 {
2891         struct btrfs_space_info *found;
2892         int i;
2893         int factor;
2894
2895         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
2896                      BTRFS_BLOCK_GROUP_RAID10))
2897                 factor = 2;
2898         else
2899                 factor = 1;
2900
2901         found = __find_space_info(info, flags);
2902         if (found) {
2903                 spin_lock(&found->lock);
2904                 found->total_bytes += total_bytes;
2905                 found->disk_total += total_bytes * factor;
2906                 found->bytes_used += bytes_used;
2907                 found->disk_used += bytes_used * factor;
2908                 found->full = 0;
2909                 spin_unlock(&found->lock);
2910                 *space_info = found;
2911                 return 0;
2912         }
2913         found = kzalloc(sizeof(*found), GFP_NOFS);
2914         if (!found)
2915                 return -ENOMEM;
2916
2917         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
2918                 INIT_LIST_HEAD(&found->block_groups[i]);
2919         init_rwsem(&found->groups_sem);
2920         spin_lock_init(&found->lock);
2921         found->flags = flags & (BTRFS_BLOCK_GROUP_DATA |
2922                                 BTRFS_BLOCK_GROUP_SYSTEM |
2923                                 BTRFS_BLOCK_GROUP_METADATA);
2924         found->total_bytes = total_bytes;
2925         found->disk_total = total_bytes * factor;
2926         found->bytes_used = bytes_used;
2927         found->disk_used = bytes_used * factor;
2928         found->bytes_pinned = 0;
2929         found->bytes_reserved = 0;
2930         found->bytes_readonly = 0;
2931         found->bytes_may_use = 0;
2932         found->full = 0;
2933         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
2934         found->chunk_alloc = 0;
2935         *space_info = found;
2936         list_add_rcu(&found->list, &info->space_info);
2937         atomic_set(&found->caching_threads, 0);
2938         return 0;
2939 }
2940
2941 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
2942 {
2943         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
2944                                    BTRFS_BLOCK_GROUP_RAID1 |
2945                                    BTRFS_BLOCK_GROUP_RAID10 |
2946                                    BTRFS_BLOCK_GROUP_DUP);
2947         if (extra_flags) {
2948                 if (flags & BTRFS_BLOCK_GROUP_DATA)
2949                         fs_info->avail_data_alloc_bits |= extra_flags;
2950                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
2951                         fs_info->avail_metadata_alloc_bits |= extra_flags;
2952                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2953                         fs_info->avail_system_alloc_bits |= extra_flags;
2954         }
2955 }
2956
2957 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
2958 {
2959         /*
2960          * we add in the count of missing devices because we want
2961          * to make sure that any RAID levels on a degraded FS
2962          * continue to be honored.
2963          */
2964         u64 num_devices = root->fs_info->fs_devices->rw_devices +
2965                 root->fs_info->fs_devices->missing_devices;
2966
2967         if (num_devices == 1)
2968                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
2969         if (num_devices < 4)
2970                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
2971
2972         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
2973             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
2974                       BTRFS_BLOCK_GROUP_RAID10))) {
2975                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
2976         }
2977
2978         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
2979             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
2980                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
2981         }
2982
2983         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
2984             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
2985              (flags & BTRFS_BLOCK_GROUP_RAID10) |
2986              (flags & BTRFS_BLOCK_GROUP_DUP)))
2987                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
2988         return flags;
2989 }
2990
2991 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
2992 {
2993         if (flags & BTRFS_BLOCK_GROUP_DATA)
2994                 flags |= root->fs_info->avail_data_alloc_bits &
2995                          root->fs_info->data_alloc_profile;
2996         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
2997                 flags |= root->fs_info->avail_system_alloc_bits &
2998                          root->fs_info->system_alloc_profile;
2999         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3000                 flags |= root->fs_info->avail_metadata_alloc_bits &
3001                          root->fs_info->metadata_alloc_profile;
3002         return btrfs_reduce_alloc_profile(root, flags);
3003 }
3004
3005 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3006 {
3007         u64 flags;
3008
3009         if (data)
3010                 flags = BTRFS_BLOCK_GROUP_DATA;
3011         else if (root == root->fs_info->chunk_root)
3012                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3013         else
3014                 flags = BTRFS_BLOCK_GROUP_METADATA;
3015
3016         return get_alloc_profile(root, flags);
3017 }
3018
3019 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
3020 {
3021         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
3022                                                        BTRFS_BLOCK_GROUP_DATA);
3023 }
3024
3025 /*
3026  * This will check the space that the inode allocates from to make sure we have
3027  * enough space for bytes.
3028  */
3029 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3030 {
3031         struct btrfs_space_info *data_sinfo;
3032         struct btrfs_root *root = BTRFS_I(inode)->root;
3033         u64 used;
3034         int ret = 0, committed = 0, alloc_chunk = 1;
3035
3036         /* make sure bytes are sectorsize aligned */
3037         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3038
3039         if (root == root->fs_info->tree_root ||
3040             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3041                 alloc_chunk = 0;
3042                 committed = 1;
3043         }
3044
3045         data_sinfo = BTRFS_I(inode)->space_info;
3046         if (!data_sinfo)
3047                 goto alloc;
3048
3049 again:
3050         /* make sure we have enough space to handle the data first */
3051         spin_lock(&data_sinfo->lock);
3052         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3053                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3054                 data_sinfo->bytes_may_use;
3055
3056         if (used + bytes > data_sinfo->total_bytes) {
3057                 struct btrfs_trans_handle *trans;
3058
3059                 /*
3060                  * if we don't have enough free bytes in this space then we need
3061                  * to alloc a new chunk.
3062                  */
3063                 if (!data_sinfo->full && alloc_chunk) {
3064                         u64 alloc_target;
3065
3066                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3067                         spin_unlock(&data_sinfo->lock);
3068 alloc:
3069                         alloc_target = btrfs_get_alloc_profile(root, 1);
3070                         trans = btrfs_join_transaction(root);
3071                         if (IS_ERR(trans))
3072                                 return PTR_ERR(trans);
3073
3074                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3075                                              bytes + 2 * 1024 * 1024,
3076                                              alloc_target,
3077                                              CHUNK_ALLOC_NO_FORCE);
3078                         btrfs_end_transaction(trans, root);
3079                         if (ret < 0) {
3080                                 if (ret != -ENOSPC)
3081                                         return ret;
3082                                 else
3083                                         goto commit_trans;
3084                         }
3085
3086                         if (!data_sinfo) {
3087                                 btrfs_set_inode_space_info(root, inode);
3088                                 data_sinfo = BTRFS_I(inode)->space_info;
3089                         }
3090                         goto again;
3091                 }
3092
3093                 /*
3094                  * If we have less pinned bytes than we want to allocate then
3095                  * don't bother committing the transaction, it won't help us.
3096                  */
3097                 if (data_sinfo->bytes_pinned < bytes)
3098                         committed = 1;
3099                 spin_unlock(&data_sinfo->lock);
3100
3101                 /* commit the current transaction and try again */
3102 commit_trans:
3103                 if (!committed &&
3104                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3105                         committed = 1;
3106                         trans = btrfs_join_transaction(root);
3107                         if (IS_ERR(trans))
3108                                 return PTR_ERR(trans);
3109                         ret = btrfs_commit_transaction(trans, root);
3110                         if (ret)
3111                                 return ret;
3112                         goto again;
3113                 }
3114
3115                 return -ENOSPC;
3116         }
3117         data_sinfo->bytes_may_use += bytes;
3118         BTRFS_I(inode)->reserved_bytes += bytes;
3119         spin_unlock(&data_sinfo->lock);
3120
3121         return 0;
3122 }
3123
3124 /*
3125  * called when we are clearing an delalloc extent from the
3126  * inode's io_tree or there was an error for whatever reason
3127  * after calling btrfs_check_data_free_space
3128  */
3129 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3130 {
3131         struct btrfs_root *root = BTRFS_I(inode)->root;
3132         struct btrfs_space_info *data_sinfo;
3133
3134         /* make sure bytes are sectorsize aligned */
3135         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3136
3137         data_sinfo = BTRFS_I(inode)->space_info;
3138         spin_lock(&data_sinfo->lock);
3139         data_sinfo->bytes_may_use -= bytes;
3140         BTRFS_I(inode)->reserved_bytes -= bytes;
3141         spin_unlock(&data_sinfo->lock);
3142 }
3143
3144 static void force_metadata_allocation(struct btrfs_fs_info *info)
3145 {
3146         struct list_head *head = &info->space_info;
3147         struct btrfs_space_info *found;
3148
3149         rcu_read_lock();
3150         list_for_each_entry_rcu(found, head, list) {
3151                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3152                         found->force_alloc = CHUNK_ALLOC_FORCE;
3153         }
3154         rcu_read_unlock();
3155 }
3156
3157 static int should_alloc_chunk(struct btrfs_root *root,
3158                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3159                               int force)
3160 {
3161         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3162         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3163         u64 thresh;
3164
3165         if (force == CHUNK_ALLOC_FORCE)
3166                 return 1;
3167
3168         /*
3169          * in limited mode, we want to have some free space up to
3170          * about 1% of the FS size.
3171          */
3172         if (force == CHUNK_ALLOC_LIMITED) {
3173                 thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
3174                 thresh = max_t(u64, 64 * 1024 * 1024,
3175                                div_factor_fine(thresh, 1));
3176
3177                 if (num_bytes - num_allocated < thresh)
3178                         return 1;
3179         }
3180
3181         /*
3182          * we have two similar checks here, one based on percentage
3183          * and once based on a hard number of 256MB.  The idea
3184          * is that if we have a good amount of free
3185          * room, don't allocate a chunk.  A good mount is
3186          * less than 80% utilized of the chunks we have allocated,
3187          * or more than 256MB free
3188          */
3189         if (num_allocated + alloc_bytes + 256 * 1024 * 1024 < num_bytes)
3190                 return 0;
3191
3192         if (num_allocated + alloc_bytes < div_factor(num_bytes, 8))
3193                 return 0;
3194
3195         thresh = btrfs_super_total_bytes(&root->fs_info->super_copy);
3196
3197         /* 256MB or 5% of the FS */
3198         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 5));
3199
3200         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 3))
3201                 return 0;
3202         return 1;
3203 }
3204
3205 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3206                           struct btrfs_root *extent_root, u64 alloc_bytes,
3207                           u64 flags, int force)
3208 {
3209         struct btrfs_space_info *space_info;
3210         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3211         int wait_for_alloc = 0;
3212         int ret = 0;
3213
3214         flags = btrfs_reduce_alloc_profile(extent_root, flags);
3215
3216         space_info = __find_space_info(extent_root->fs_info, flags);
3217         if (!space_info) {
3218                 ret = update_space_info(extent_root->fs_info, flags,
3219                                         0, 0, &space_info);
3220                 BUG_ON(ret);
3221         }
3222         BUG_ON(!space_info);
3223
3224 again:
3225         spin_lock(&space_info->lock);
3226         if (space_info->force_alloc)
3227                 force = space_info->force_alloc;
3228         if (space_info->full) {
3229                 spin_unlock(&space_info->lock);
3230                 return 0;
3231         }
3232
3233         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3234                 spin_unlock(&space_info->lock);
3235                 return 0;
3236         } else if (space_info->chunk_alloc) {
3237                 wait_for_alloc = 1;
3238         } else {
3239                 space_info->chunk_alloc = 1;
3240         }
3241
3242         spin_unlock(&space_info->lock);
3243
3244         mutex_lock(&fs_info->chunk_mutex);
3245
3246         /*
3247          * The chunk_mutex is held throughout the entirety of a chunk
3248          * allocation, so once we've acquired the chunk_mutex we know that the
3249          * other guy is done and we need to recheck and see if we should
3250          * allocate.
3251          */
3252         if (wait_for_alloc) {
3253                 mutex_unlock(&fs_info->chunk_mutex);
3254                 wait_for_alloc = 0;
3255                 goto again;
3256         }
3257
3258         /*
3259          * If we have mixed data/metadata chunks we want to make sure we keep
3260          * allocating mixed chunks instead of individual chunks.
3261          */
3262         if (btrfs_mixed_space_info(space_info))
3263                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3264
3265         /*
3266          * if we're doing a data chunk, go ahead and make sure that
3267          * we keep a reasonable number of metadata chunks allocated in the
3268          * FS as well.
3269          */
3270         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3271                 fs_info->data_chunk_allocations++;
3272                 if (!(fs_info->data_chunk_allocations %
3273                       fs_info->metadata_ratio))
3274                         force_metadata_allocation(fs_info);
3275         }
3276
3277         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3278         spin_lock(&space_info->lock);
3279         if (ret)
3280                 space_info->full = 1;
3281         else
3282                 ret = 1;
3283
3284         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3285         space_info->chunk_alloc = 0;
3286         spin_unlock(&space_info->lock);
3287         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3288         return ret;
3289 }
3290
3291 /*
3292  * shrink metadata reservation for delalloc
3293  */
3294 static int shrink_delalloc(struct btrfs_trans_handle *trans,
3295                            struct btrfs_root *root, u64 to_reclaim, int sync)
3296 {
3297         struct btrfs_block_rsv *block_rsv;
3298         struct btrfs_space_info *space_info;
3299         u64 reserved;
3300         u64 max_reclaim;
3301         u64 reclaimed = 0;
3302         long time_left;
3303         int nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3304         int loops = 0;
3305         unsigned long progress;
3306
3307         block_rsv = &root->fs_info->delalloc_block_rsv;
3308         space_info = block_rsv->space_info;
3309
3310         smp_mb();
3311         reserved = space_info->bytes_reserved;
3312         progress = space_info->reservation_progress;
3313
3314         if (reserved == 0)
3315                 return 0;
3316
3317         /* nothing to shrink - nothing to reclaim */
3318         if (root->fs_info->delalloc_bytes == 0)
3319                 return 0;
3320
3321         max_reclaim = min(reserved, to_reclaim);
3322
3323         while (loops < 1024) {
3324                 /* have the flusher threads jump in and do some IO */
3325                 smp_mb();
3326                 nr_pages = min_t(unsigned long, nr_pages,
3327                        root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
3328                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages);
3329
3330                 spin_lock(&space_info->lock);
3331                 if (reserved > space_info->bytes_reserved)
3332                         reclaimed += reserved - space_info->bytes_reserved;
3333                 reserved = space_info->bytes_reserved;
3334                 spin_unlock(&space_info->lock);
3335
3336                 loops++;
3337
3338                 if (reserved == 0 || reclaimed >= max_reclaim)
3339                         break;
3340
3341                 if (trans && trans->transaction->blocked)
3342                         return -EAGAIN;
3343
3344                 time_left = schedule_timeout_interruptible(1);
3345
3346                 /* We were interrupted, exit */
3347                 if (time_left)
3348                         break;
3349
3350                 /* we've kicked the IO a few times, if anything has been freed,
3351                  * exit.  There is no sense in looping here for a long time
3352                  * when we really need to commit the transaction, or there are
3353                  * just too many writers without enough free space
3354                  */
3355
3356                 if (loops > 3) {
3357                         smp_mb();
3358                         if (progress != space_info->reservation_progress)
3359                                 break;
3360                 }
3361
3362         }
3363         return reclaimed >= to_reclaim;
3364 }
3365
3366 /*
3367  * Retries tells us how many times we've called reserve_metadata_bytes.  The
3368  * idea is if this is the first call (retries == 0) then we will add to our
3369  * reserved count if we can't make the allocation in order to hold our place
3370  * while we go and try and free up space.  That way for retries > 1 we don't try
3371  * and add space, we just check to see if the amount of unused space is >= the
3372  * total space, meaning that our reservation is valid.
3373  *
3374  * However if we don't intend to retry this reservation, pass -1 as retries so
3375  * that it short circuits this logic.
3376  */
3377 static int reserve_metadata_bytes(struct btrfs_trans_handle *trans,
3378                                   struct btrfs_root *root,
3379                                   struct btrfs_block_rsv *block_rsv,
3380                                   u64 orig_bytes, int flush)
3381 {
3382         struct btrfs_space_info *space_info = block_rsv->space_info;
3383         u64 unused;
3384         u64 num_bytes = orig_bytes;
3385         int retries = 0;
3386         int ret = 0;
3387         bool reserved = false;
3388         bool committed = false;
3389
3390 again:
3391         ret = -ENOSPC;
3392         if (reserved)
3393                 num_bytes = 0;
3394
3395         spin_lock(&space_info->lock);
3396         unused = space_info->bytes_used + space_info->bytes_reserved +
3397                  space_info->bytes_pinned + space_info->bytes_readonly +
3398                  space_info->bytes_may_use;
3399
3400         /*
3401          * The idea here is that we've not already over-reserved the block group
3402          * then we can go ahead and save our reservation first and then start
3403          * flushing if we need to.  Otherwise if we've already overcommitted
3404          * lets start flushing stuff first and then come back and try to make
3405          * our reservation.
3406          */
3407         if (unused <= space_info->total_bytes) {
3408                 unused = space_info->total_bytes - unused;
3409                 if (unused >= num_bytes) {
3410                         if (!reserved)
3411                                 space_info->bytes_reserved += orig_bytes;
3412                         ret = 0;
3413                 } else {
3414                         /*
3415                          * Ok set num_bytes to orig_bytes since we aren't
3416                          * overocmmitted, this way we only try and reclaim what
3417                          * we need.
3418                          */
3419                         num_bytes = orig_bytes;
3420                 }
3421         } else {
3422                 /*
3423                  * Ok we're over committed, set num_bytes to the overcommitted
3424                  * amount plus the amount of bytes that we need for this
3425                  * reservation.
3426                  */
3427                 num_bytes = unused - space_info->total_bytes +
3428                         (orig_bytes * (retries + 1));
3429         }
3430
3431         /*
3432          * Couldn't make our reservation, save our place so while we're trying
3433          * to reclaim space we can actually use it instead of somebody else
3434          * stealing it from us.
3435          */
3436         if (ret && !reserved) {
3437                 space_info->bytes_reserved += orig_bytes;
3438                 reserved = true;
3439         }
3440
3441         spin_unlock(&space_info->lock);
3442
3443         if (!ret)
3444                 return 0;
3445
3446         if (!flush)
3447                 goto out;
3448
3449         /*
3450          * We do synchronous shrinking since we don't actually unreserve
3451          * metadata until after the IO is completed.
3452          */
3453         ret = shrink_delalloc(trans, root, num_bytes, 1);
3454         if (ret > 0)
3455                 return 0;
3456         else if (ret < 0)
3457                 goto out;
3458
3459         /*
3460          * So if we were overcommitted it's possible that somebody else flushed
3461          * out enough space and we simply didn't have enough space to reclaim,
3462          * so go back around and try again.
3463          */
3464         if (retries < 2) {
3465                 retries++;
3466                 goto again;
3467         }
3468
3469         spin_lock(&space_info->lock);
3470         /*
3471          * Not enough space to be reclaimed, don't bother committing the
3472          * transaction.
3473          */
3474         if (space_info->bytes_pinned < orig_bytes)
3475                 ret = -ENOSPC;
3476         spin_unlock(&space_info->lock);
3477         if (ret)
3478                 goto out;
3479
3480         ret = -EAGAIN;
3481         if (trans || committed)
3482                 goto out;
3483
3484         ret = -ENOSPC;
3485         trans = btrfs_join_transaction(root);
3486         if (IS_ERR(trans))
3487                 goto out;
3488         ret = btrfs_commit_transaction(trans, root);
3489         if (!ret) {
3490                 trans = NULL;
3491                 committed = true;
3492                 goto again;
3493         }
3494
3495 out:
3496         if (reserved) {
3497                 spin_lock(&space_info->lock);
3498                 space_info->bytes_reserved -= orig_bytes;
3499                 spin_unlock(&space_info->lock);
3500         }
3501
3502         return ret;
3503 }
3504
3505 static struct btrfs_block_rsv *get_block_rsv(struct btrfs_trans_handle *trans,
3506                                              struct btrfs_root *root)
3507 {
3508         struct btrfs_block_rsv *block_rsv;
3509         if (root->ref_cows)
3510                 block_rsv = trans->block_rsv;
3511         else
3512                 block_rsv = root->block_rsv;
3513
3514         if (!block_rsv)
3515                 block_rsv = &root->fs_info->empty_block_rsv;
3516
3517         return block_rsv;
3518 }
3519
3520 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
3521                                u64 num_bytes)
3522 {
3523         int ret = -ENOSPC;
3524         spin_lock(&block_rsv->lock);
3525         if (block_rsv->reserved >= num_bytes) {
3526                 block_rsv->reserved -= num_bytes;
3527                 if (block_rsv->reserved < block_rsv->size)
3528                         block_rsv->full = 0;
3529                 ret = 0;
3530         }
3531         spin_unlock(&block_rsv->lock);
3532         return ret;
3533 }
3534
3535 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
3536                                 u64 num_bytes, int update_size)
3537 {
3538         spin_lock(&block_rsv->lock);
3539         block_rsv->reserved += num_bytes;
3540         if (update_size)
3541                 block_rsv->size += num_bytes;
3542         else if (block_rsv->reserved >= block_rsv->size)
3543                 block_rsv->full = 1;
3544         spin_unlock(&block_rsv->lock);
3545 }
3546
3547 static void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv,
3548                                     struct btrfs_block_rsv *dest, u64 num_bytes)
3549 {
3550         struct btrfs_space_info *space_info = block_rsv->space_info;
3551
3552         spin_lock(&block_rsv->lock);
3553         if (num_bytes == (u64)-1)
3554                 num_bytes = block_rsv->size;
3555         block_rsv->size -= num_bytes;
3556         if (block_rsv->reserved >= block_rsv->size) {
3557                 num_bytes = block_rsv->reserved - block_rsv->size;
3558                 block_rsv->reserved = block_rsv->size;
3559                 block_rsv->full = 1;
3560         } else {
3561                 num_bytes = 0;
3562         }
3563         spin_unlock(&block_rsv->lock);
3564
3565         if (num_bytes > 0) {
3566                 if (dest) {
3567                         spin_lock(&dest->lock);
3568                         if (!dest->full) {
3569                                 u64 bytes_to_add;
3570
3571                                 bytes_to_add = dest->size - dest->reserved;
3572                                 bytes_to_add = min(num_bytes, bytes_to_add);
3573                                 dest->reserved += bytes_to_add;
3574                                 if (dest->reserved >= dest->size)
3575                                         dest->full = 1;
3576                                 num_bytes -= bytes_to_add;
3577                         }
3578                         spin_unlock(&dest->lock);
3579                 }
3580                 if (num_bytes) {
3581                         spin_lock(&space_info->lock);
3582                         space_info->bytes_reserved -= num_bytes;
3583                         space_info->reservation_progress++;
3584                         spin_unlock(&space_info->lock);
3585                 }
3586         }
3587 }
3588
3589 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
3590                                    struct btrfs_block_rsv *dst, u64 num_bytes)
3591 {
3592         int ret;
3593
3594         ret = block_rsv_use_bytes(src, num_bytes);
3595         if (ret)
3596                 return ret;
3597
3598         block_rsv_add_bytes(dst, num_bytes, 1);
3599         return 0;
3600 }
3601
3602 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
3603 {
3604         memset(rsv, 0, sizeof(*rsv));
3605         spin_lock_init(&rsv->lock);
3606         atomic_set(&rsv->usage, 1);
3607         rsv->priority = 6;
3608         INIT_LIST_HEAD(&rsv->list);
3609 }
3610
3611 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
3612 {
3613         struct btrfs_block_rsv *block_rsv;
3614         struct btrfs_fs_info *fs_info = root->fs_info;
3615
3616         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
3617         if (!block_rsv)
3618                 return NULL;
3619
3620         btrfs_init_block_rsv(block_rsv);
3621         block_rsv->space_info = __find_space_info(fs_info,
3622                                                   BTRFS_BLOCK_GROUP_METADATA);
3623         return block_rsv;
3624 }
3625
3626 void btrfs_free_block_rsv(struct btrfs_root *root,
3627                           struct btrfs_block_rsv *rsv)
3628 {
3629         if (rsv && atomic_dec_and_test(&rsv->usage)) {
3630                 btrfs_block_rsv_release(root, rsv, (u64)-1);
3631                 if (!rsv->durable)
3632                         kfree(rsv);
3633         }
3634 }
3635
3636 /*
3637  * make the block_rsv struct be able to capture freed space.
3638  * the captured space will re-add to the the block_rsv struct
3639  * after transaction commit
3640  */
3641 void btrfs_add_durable_block_rsv(struct btrfs_fs_info *fs_info,
3642                                  struct btrfs_block_rsv *block_rsv)
3643 {
3644         block_rsv->durable = 1;
3645         mutex_lock(&fs_info->durable_block_rsv_mutex);
3646         list_add_tail(&block_rsv->list, &fs_info->durable_block_rsv_list);
3647         mutex_unlock(&fs_info->durable_block_rsv_mutex);
3648 }
3649
3650 int btrfs_block_rsv_add(struct btrfs_trans_handle *trans,
3651                         struct btrfs_root *root,
3652                         struct btrfs_block_rsv *block_rsv,
3653                         u64 num_bytes)
3654 {
3655         int ret;
3656
3657         if (num_bytes == 0)
3658                 return 0;
3659
3660         ret = reserve_metadata_bytes(trans, root, block_rsv, num_bytes, 1);
3661         if (!ret) {
3662                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
3663                 return 0;
3664         }
3665
3666         return ret;
3667 }
3668
3669 int btrfs_block_rsv_check(struct btrfs_trans_handle *trans,
3670                           struct btrfs_root *root,
3671                           struct btrfs_block_rsv *block_rsv,
3672                           u64 min_reserved, int min_factor)
3673 {
3674         u64 num_bytes = 0;
3675         int commit_trans = 0;
3676         int ret = -ENOSPC;
3677
3678         if (!block_rsv)
3679                 return 0;
3680
3681         spin_lock(&block_rsv->lock);
3682         if (min_factor > 0)
3683                 num_bytes = div_factor(block_rsv->size, min_factor);
3684         if (min_reserved > num_bytes)
3685                 num_bytes = min_reserved;
3686
3687         if (block_rsv->reserved >= num_bytes) {
3688                 ret = 0;
3689         } else {
3690                 num_bytes -= block_rsv->reserved;
3691                 if (block_rsv->durable &&
3692                     block_rsv->freed[0] + block_rsv->freed[1] >= num_bytes)
3693                         commit_trans = 1;
3694         }
3695         spin_unlock(&block_rsv->lock);
3696         if (!ret)
3697                 return 0;
3698
3699         if (block_rsv->refill_used) {
3700                 ret = reserve_metadata_bytes(trans, root, block_rsv,
3701                                              num_bytes, 0);
3702                 if (!ret) {
3703                         block_rsv_add_bytes(block_rsv, num_bytes, 0);
3704                         return 0;
3705                 }
3706         }
3707
3708         if (commit_trans) {
3709                 if (trans)
3710                         return -EAGAIN;
3711
3712                 trans = btrfs_join_transaction(root);
3713                 BUG_ON(IS_ERR(trans));
3714                 ret = btrfs_commit_transaction(trans, root);
3715                 return 0;
3716         }
3717
3718         return -ENOSPC;
3719 }
3720
3721 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
3722                             struct btrfs_block_rsv *dst_rsv,
3723                             u64 num_bytes)
3724 {
3725         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3726 }
3727
3728 void btrfs_block_rsv_release(struct btrfs_root *root,
3729                              struct btrfs_block_rsv *block_rsv,
3730                              u64 num_bytes)
3731 {
3732         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3733         if (global_rsv->full || global_rsv == block_rsv ||
3734             block_rsv->space_info != global_rsv->space_info)
3735                 global_rsv = NULL;
3736         block_rsv_release_bytes(block_rsv, global_rsv, num_bytes);
3737 }
3738
3739 /*
3740  * helper to calculate size of global block reservation.
3741  * the desired value is sum of space used by extent tree,
3742  * checksum tree and root tree
3743  */
3744 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
3745 {
3746         struct btrfs_space_info *sinfo;
3747         u64 num_bytes;
3748         u64 meta_used;
3749         u64 data_used;
3750         int csum_size = btrfs_super_csum_size(&fs_info->super_copy);
3751
3752         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
3753         spin_lock(&sinfo->lock);
3754         data_used = sinfo->bytes_used;
3755         spin_unlock(&sinfo->lock);
3756
3757         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3758         spin_lock(&sinfo->lock);
3759         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
3760                 data_used = 0;
3761         meta_used = sinfo->bytes_used;
3762         spin_unlock(&sinfo->lock);
3763
3764         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
3765                     csum_size * 2;
3766         num_bytes += div64_u64(data_used + meta_used, 50);
3767
3768         if (num_bytes * 3 > meta_used)
3769                 num_bytes = div64_u64(meta_used, 3);
3770
3771         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
3772 }
3773
3774 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
3775 {
3776         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
3777         struct btrfs_space_info *sinfo = block_rsv->space_info;
3778         u64 num_bytes;
3779
3780         num_bytes = calc_global_metadata_size(fs_info);
3781
3782         spin_lock(&block_rsv->lock);
3783         spin_lock(&sinfo->lock);
3784
3785         block_rsv->size = num_bytes;
3786
3787         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
3788                     sinfo->bytes_reserved + sinfo->bytes_readonly +
3789                     sinfo->bytes_may_use;
3790
3791         if (sinfo->total_bytes > num_bytes) {
3792                 num_bytes = sinfo->total_bytes - num_bytes;
3793                 block_rsv->reserved += num_bytes;
3794                 sinfo->bytes_reserved += num_bytes;
3795         }
3796
3797         if (block_rsv->reserved >= block_rsv->size) {
3798                 num_bytes = block_rsv->reserved - block_rsv->size;
3799                 sinfo->bytes_reserved -= num_bytes;
3800                 sinfo->reservation_progress++;
3801                 block_rsv->reserved = block_rsv->size;
3802                 block_rsv->full = 1;
3803         }
3804
3805         spin_unlock(&sinfo->lock);
3806         spin_unlock(&block_rsv->lock);
3807 }
3808
3809 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
3810 {
3811         struct btrfs_space_info *space_info;
3812
3813         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3814         fs_info->chunk_block_rsv.space_info = space_info;
3815         fs_info->chunk_block_rsv.priority = 10;
3816
3817         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3818         fs_info->global_block_rsv.space_info = space_info;
3819         fs_info->global_block_rsv.priority = 10;
3820         fs_info->global_block_rsv.refill_used = 1;
3821         fs_info->delalloc_block_rsv.space_info = space_info;
3822         fs_info->trans_block_rsv.space_info = space_info;
3823         fs_info->empty_block_rsv.space_info = space_info;
3824         fs_info->empty_block_rsv.priority = 10;
3825
3826         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
3827         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
3828         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
3829         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
3830         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
3831
3832         btrfs_add_durable_block_rsv(fs_info, &fs_info->global_block_rsv);
3833
3834         btrfs_add_durable_block_rsv(fs_info, &fs_info->delalloc_block_rsv);
3835
3836         update_global_block_rsv(fs_info);
3837 }
3838
3839 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
3840 {
3841         block_rsv_release_bytes(&fs_info->global_block_rsv, NULL, (u64)-1);
3842         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
3843         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
3844         WARN_ON(fs_info->trans_block_rsv.size > 0);
3845         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
3846         WARN_ON(fs_info->chunk_block_rsv.size > 0);
3847         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
3848 }
3849
3850 int btrfs_truncate_reserve_metadata(struct btrfs_trans_handle *trans,
3851                                     struct btrfs_root *root,
3852                                     struct btrfs_block_rsv *rsv)
3853 {
3854         struct btrfs_block_rsv *trans_rsv = &root->fs_info->trans_block_rsv;
3855         u64 num_bytes;
3856         int ret;
3857
3858         /*
3859          * Truncate should be freeing data, but give us 2 items just in case it
3860          * needs to use some space.  We may want to be smarter about this in the
3861          * future.
3862          */
3863         num_bytes = btrfs_calc_trans_metadata_size(root, 2);
3864
3865         /* We already have enough bytes, just return */
3866         if (rsv->reserved >= num_bytes)
3867                 return 0;
3868
3869         num_bytes -= rsv->reserved;
3870
3871         /*
3872          * You should have reserved enough space before hand to do this, so this
3873          * should not fail.
3874          */
3875         ret = block_rsv_migrate_bytes(trans_rsv, rsv, num_bytes);
3876         BUG_ON(ret);
3877
3878         return 0;
3879 }
3880
3881 int btrfs_trans_reserve_metadata(struct btrfs_trans_handle *trans,
3882                                  struct btrfs_root *root,
3883                                  int num_items)
3884 {
3885         u64 num_bytes;
3886         int ret;
3887
3888         if (num_items == 0 || root->fs_info->chunk_root == root)
3889                 return 0;
3890
3891         num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
3892         ret = btrfs_block_rsv_add(trans, root, &root->fs_info->trans_block_rsv,
3893                                   num_bytes);
3894         if (!ret) {
3895                 trans->bytes_reserved += num_bytes;
3896                 trans->block_rsv = &root->fs_info->trans_block_rsv;
3897         }
3898         return ret;
3899 }
3900
3901 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
3902                                   struct btrfs_root *root)
3903 {
3904         if (!trans->bytes_reserved)
3905                 return;
3906
3907         BUG_ON(trans->block_rsv != &root->fs_info->trans_block_rsv);
3908         btrfs_block_rsv_release(root, trans->block_rsv,
3909                                 trans->bytes_reserved);
3910         trans->bytes_reserved = 0;
3911 }
3912
3913 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
3914                                   struct inode *inode)
3915 {
3916         struct btrfs_root *root = BTRFS_I(inode)->root;
3917         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
3918         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
3919
3920         /*
3921          * We need to hold space in order to delete our orphan item once we've
3922          * added it, so this takes the reservation so we can release it later
3923          * when we are truly done with the orphan item.
3924          */
3925         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
3926         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3927 }
3928
3929 void btrfs_orphan_release_metadata(struct inode *inode)
3930 {
3931         struct btrfs_root *root = BTRFS_I(inode)->root;
3932         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
3933         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
3934 }
3935
3936 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
3937                                 struct btrfs_pending_snapshot *pending)
3938 {
3939         struct btrfs_root *root = pending->root;
3940         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
3941         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
3942         /*
3943          * two for root back/forward refs, two for directory entries
3944          * and one for root of the snapshot.
3945          */
3946         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
3947         dst_rsv->space_info = src_rsv->space_info;
3948         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3949 }
3950
3951 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes)
3952 {
3953         return num_bytes >>= 3;
3954 }
3955
3956 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
3957 {
3958         struct btrfs_root *root = BTRFS_I(inode)->root;
3959         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
3960         u64 to_reserve;
3961         int nr_extents;
3962         int reserved_extents;
3963         int ret;
3964
3965         if (btrfs_transaction_in_commit(root->fs_info))
3966                 schedule_timeout(1);
3967
3968         num_bytes = ALIGN(num_bytes, root->sectorsize);
3969
3970         nr_extents = atomic_read(&BTRFS_I(inode)->outstanding_extents) + 1;
3971         reserved_extents = atomic_read(&BTRFS_I(inode)->reserved_extents);
3972
3973         if (nr_extents > reserved_extents) {
3974                 nr_extents -= reserved_extents;
3975                 to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
3976         } else {
3977                 nr_extents = 0;
3978                 to_reserve = 0;
3979         }
3980
3981         to_reserve += calc_csum_metadata_size(inode, num_bytes);
3982         ret = reserve_metadata_bytes(NULL, root, block_rsv, to_reserve, 1);
3983         if (ret)
3984                 return ret;
3985
3986         atomic_add(nr_extents, &BTRFS_I(inode)->reserved_extents);
3987         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
3988
3989         block_rsv_add_bytes(block_rsv, to_reserve, 1);
3990
3991         if (block_rsv->size > 512 * 1024 * 1024)
3992                 shrink_delalloc(NULL, root, to_reserve, 0);
3993
3994         return 0;
3995 }
3996
3997 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
3998 {
3999         struct btrfs_root *root = BTRFS_I(inode)->root;
4000         u64 to_free;
4001         int nr_extents;
4002         int reserved_extents;
4003
4004         num_bytes = ALIGN(num_bytes, root->sectorsize);
4005         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
4006         WARN_ON(atomic_read(&BTRFS_I(inode)->outstanding_extents) < 0);
4007
4008         reserved_extents = atomic_read(&BTRFS_I(inode)->reserved_extents);
4009         do {
4010                 int old, new;
4011
4012                 nr_extents = atomic_read(&BTRFS_I(inode)->outstanding_extents);
4013                 if (nr_extents >= reserved_extents) {
4014                         nr_extents = 0;
4015                         break;
4016                 }
4017                 old = reserved_extents;
4018                 nr_extents = reserved_extents - nr_extents;
4019                 new = reserved_extents - nr_extents;
4020                 old = atomic_cmpxchg(&BTRFS_I(inode)->reserved_extents,
4021                                      reserved_extents, new);
4022                 if (likely(old == reserved_extents))
4023                         break;
4024                 reserved_extents = old;
4025         } while (1);
4026
4027         to_free = calc_csum_metadata_size(inode, num_bytes);
4028         if (nr_extents > 0)
4029                 to_free += btrfs_calc_trans_metadata_size(root, nr_extents);
4030
4031         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4032                                 to_free);
4033 }
4034
4035 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4036 {
4037         int ret;
4038
4039         ret = btrfs_check_data_free_space(inode, num_bytes);
4040         if (ret)
4041                 return ret;
4042
4043         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4044         if (ret) {
4045                 btrfs_free_reserved_data_space(inode, num_bytes);
4046                 return ret;
4047         }
4048
4049         return 0;
4050 }
4051
4052 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4053 {
4054         btrfs_delalloc_release_metadata(inode, num_bytes);
4055         btrfs_free_reserved_data_space(inode, num_bytes);
4056 }
4057
4058 static int update_block_group(struct btrfs_trans_handle *trans,
4059                               struct btrfs_root *root,
4060                               u64 bytenr, u64 num_bytes, int alloc)
4061 {
4062         struct btrfs_block_group_cache *cache = NULL;
4063         struct btrfs_fs_info *info = root->fs_info;
4064         u64 total = num_bytes;
4065         u64 old_val;
4066         u64 byte_in_group;
4067         int factor;
4068
4069         /* block accounting for super block */
4070         spin_lock(&info->delalloc_lock);
4071         old_val = btrfs_super_bytes_used(&info->super_copy);
4072         if (alloc)
4073                 old_val += num_bytes;
4074         else
4075                 old_val -= num_bytes;
4076         btrfs_set_super_bytes_used(&info->super_copy, old_val);
4077         spin_unlock(&info->delalloc_lock);
4078
4079         while (total) {
4080                 cache = btrfs_lookup_block_group(info, bytenr);
4081                 if (!cache)
4082                         return -1;
4083                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4084                                     BTRFS_BLOCK_GROUP_RAID1 |
4085                                     BTRFS_BLOCK_GROUP_RAID10))
4086                         factor = 2;
4087                 else
4088                         factor = 1;
4089                 /*
4090                  * If this block group has free space cache written out, we
4091                  * need to make sure to load it if we are removing space.  This
4092                  * is because we need the unpinning stage to actually add the
4093                  * space back to the block group, otherwise we will leak space.
4094                  */
4095                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4096                         cache_block_group(cache, trans, NULL, 1);
4097
4098                 byte_in_group = bytenr - cache->key.objectid;
4099                 WARN_ON(byte_in_group > cache->key.offset);
4100
4101                 spin_lock(&cache->space_info->lock);
4102                 spin_lock(&cache->lock);
4103
4104                 if (btrfs_super_cache_generation(&info->super_copy) != 0 &&
4105                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4106                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4107
4108                 cache->dirty = 1;
4109                 old_val = btrfs_block_group_used(&cache->item);
4110                 num_bytes = min(total, cache->key.offset - byte_in_group);
4111                 if (alloc) {
4112                         old_val += num_bytes;
4113                         btrfs_set_block_group_used(&cache->item, old_val);
4114                         cache->reserved -= num_bytes;
4115                         cache->space_info->bytes_reserved -= num_bytes;
4116                         cache->space_info->reservation_progress++;
4117                         cache->space_info->bytes_used += num_bytes;
4118                         cache->space_info->disk_used += num_bytes * factor;
4119                         spin_unlock(&cache->lock);
4120                         spin_unlock(&cache->space_info->lock);
4121                 } else {
4122                         old_val -= num_bytes;
4123                         btrfs_set_block_group_used(&cache->item, old_val);
4124                         cache->pinned += num_bytes;
4125                         cache->space_info->bytes_pinned += num_bytes;
4126                         cache->space_info->bytes_used -= num_bytes;
4127                         cache->space_info->disk_used -= num_bytes * factor;
4128                         spin_unlock(&cache->lock);
4129                         spin_unlock(&cache->space_info->lock);
4130
4131                         set_extent_dirty(info->pinned_extents,
4132                                          bytenr, bytenr + num_bytes - 1,
4133                                          GFP_NOFS | __GFP_NOFAIL);
4134                 }
4135                 btrfs_put_block_group(cache);
4136                 total -= num_bytes;
4137                 bytenr += num_bytes;
4138         }
4139         return 0;
4140 }
4141
4142 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4143 {
4144         struct btrfs_block_group_cache *cache;
4145         u64 bytenr;
4146
4147         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4148         if (!cache)
4149                 return 0;
4150
4151         bytenr = cache->key.objectid;
4152         btrfs_put_block_group(cache);
4153
4154         return bytenr;
4155 }
4156
4157 static int pin_down_extent(struct btrfs_root *root,
4158                            struct btrfs_block_group_cache *cache,
4159                            u64 bytenr, u64 num_bytes, int reserved)
4160 {
4161         spin_lock(&cache->space_info->lock);
4162         spin_lock(&cache->lock);
4163         cache->pinned += num_bytes;
4164         cache->space_info->bytes_pinned += num_bytes;
4165         if (reserved) {
4166                 cache->reserved -= num_bytes;
4167                 cache->space_info->bytes_reserved -= num_bytes;
4168                 cache->space_info->reservation_progress++;
4169         }
4170         spin_unlock(&cache->lock);
4171         spin_unlock(&cache->space_info->lock);
4172
4173         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4174                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4175         return 0;
4176 }
4177
4178 /*
4179  * this function must be called within transaction
4180  */
4181 int btrfs_pin_extent(struct btrfs_root *root,
4182                      u64 bytenr, u64 num_bytes, int reserved)
4183 {
4184         struct btrfs_block_group_cache *cache;
4185
4186         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4187         BUG_ON(!cache);
4188
4189         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4190
4191         btrfs_put_block_group(cache);
4192         return 0;
4193 }
4194
4195 /*
4196  * update size of reserved extents. this function may return -EAGAIN
4197  * if 'reserve' is true or 'sinfo' is false.
4198  */
4199 int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4200                                 u64 num_bytes, int reserve, int sinfo)
4201 {
4202         int ret = 0;
4203         if (sinfo) {
4204                 struct btrfs_space_info *space_info = cache->space_info;
4205                 spin_lock(&space_info->lock);
4206                 spin_lock(&cache->lock);
4207                 if (reserve) {
4208                         if (cache->ro) {
4209                                 ret = -EAGAIN;
4210                         } else {
4211                                 cache->reserved += num_bytes;
4212                                 space_info->bytes_reserved += num_bytes;
4213                         }
4214                 } else {
4215                         if (cache->ro)
4216                                 space_info->bytes_readonly += num_bytes;
4217                         cache->reserved -= num_bytes;
4218                         space_info->bytes_reserved -= num_bytes;
4219                         space_info->reservation_progress++;
4220                 }
4221                 spin_unlock(&cache->lock);
4222                 spin_unlock(&space_info->lock);
4223         } else {
4224                 spin_lock(&cache->lock);
4225                 if (cache->ro) {
4226                         ret = -EAGAIN;
4227                 } else {
4228                         if (reserve)
4229                                 cache->reserved += num_bytes;
4230                         else
4231                                 cache->reserved -= num_bytes;
4232                 }
4233                 spin_unlock(&cache->lock);
4234         }
4235         return ret;
4236 }
4237
4238 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4239                                 struct btrfs_root *root)
4240 {
4241         struct btrfs_fs_info *fs_info = root->fs_info;
4242         struct btrfs_caching_control *next;
4243         struct btrfs_caching_control *caching_ctl;
4244         struct btrfs_block_group_cache *cache;
4245
4246         down_write(&fs_info->extent_commit_sem);
4247
4248         list_for_each_entry_safe(caching_ctl, next,
4249                                  &fs_info->caching_block_groups, list) {
4250                 cache = caching_ctl->block_group;
4251                 if (block_group_cache_done(cache)) {
4252                         cache->last_byte_to_unpin = (u64)-1;
4253                         list_del_init(&caching_ctl->list);
4254                         put_caching_control(caching_ctl);
4255                 } else {
4256                         cache->last_byte_to_unpin = caching_ctl->progress;
4257                 }
4258         }
4259
4260         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4261                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4262         else
4263                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4264
4265         up_write(&fs_info->extent_commit_sem);
4266
4267         update_global_block_rsv(fs_info);
4268         return 0;
4269 }
4270
4271 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4272 {
4273         struct btrfs_fs_info *fs_info = root->fs_info;
4274         struct btrfs_block_group_cache *cache = NULL;
4275         u64 len;
4276
4277         while (start <= end) {
4278                 if (!cache ||
4279                     start >= cache->key.objectid + cache->key.offset) {
4280                         if (cache)
4281                                 btrfs_put_block_group(cache);
4282                         cache = btrfs_lookup_block_group(fs_info, start);
4283                         BUG_ON(!cache);
4284                 }
4285
4286                 len = cache->key.objectid + cache->key.offset - start;
4287                 len = min(len, end + 1 - start);
4288
4289                 if (start < cache->last_byte_to_unpin) {
4290                         len = min(len, cache->last_byte_to_unpin - start);
4291                         btrfs_add_free_space(cache, start, len);
4292                 }
4293
4294                 start += len;
4295
4296                 spin_lock(&cache->space_info->lock);
4297                 spin_lock(&cache->lock);
4298                 cache->pinned -= len;
4299                 cache->space_info->bytes_pinned -= len;
4300                 if (cache->ro) {
4301                         cache->space_info->bytes_readonly += len;
4302                 } else if (cache->reserved_pinned > 0) {
4303                         len = min(len, cache->reserved_pinned);
4304                         cache->reserved_pinned -= len;
4305                         cache->space_info->bytes_reserved += len;
4306                 }
4307                 spin_unlock(&cache->lock);
4308                 spin_unlock(&cache->space_info->lock);
4309         }
4310
4311         if (cache)
4312                 btrfs_put_block_group(cache);
4313         return 0;
4314 }
4315
4316 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4317                                struct btrfs_root *root)
4318 {
4319         struct btrfs_fs_info *fs_info = root->fs_info;
4320         struct extent_io_tree *unpin;
4321         struct btrfs_block_rsv *block_rsv;
4322         struct btrfs_block_rsv *next_rsv;
4323         u64 start;
4324         u64 end;
4325         int idx;
4326         int ret;
4327
4328         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4329                 unpin = &fs_info->freed_extents[1];
4330         else
4331                 unpin = &fs_info->freed_extents[0];
4332
4333         while (1) {
4334                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4335                                             EXTENT_DIRTY);
4336                 if (ret)
4337                         break;
4338
4339                 if (btrfs_test_opt(root, DISCARD))
4340                         ret = btrfs_discard_extent(root, start,
4341                                                    end + 1 - start, NULL);
4342
4343                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4344                 unpin_extent_range(root, start, end);
4345                 cond_resched();
4346         }
4347
4348         mutex_lock(&fs_info->durable_block_rsv_mutex);
4349         list_for_each_entry_safe(block_rsv, next_rsv,
4350                                  &fs_info->durable_block_rsv_list, list) {
4351
4352                 idx = trans->transid & 0x1;
4353                 if (block_rsv->freed[idx] > 0) {
4354                         block_rsv_add_bytes(block_rsv,
4355                                             block_rsv->freed[idx], 0);
4356                         block_rsv->freed[idx] = 0;
4357                 }
4358                 if (atomic_read(&block_rsv->usage) == 0) {
4359                         btrfs_block_rsv_release(root, block_rsv, (u64)-1);
4360
4361                         if (block_rsv->freed[0] == 0 &&
4362                             block_rsv->freed[1] == 0) {
4363                                 list_del_init(&block_rsv->list);
4364                                 kfree(block_rsv);
4365                         }
4366                 } else {
4367                         btrfs_block_rsv_release(root, block_rsv, 0);
4368                 }
4369         }
4370         mutex_unlock(&fs_info->durable_block_rsv_mutex);
4371
4372         return 0;
4373 }
4374
4375 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
4376                                 struct btrfs_root *root,
4377                                 u64 bytenr, u64 num_bytes, u64 parent,
4378                                 u64 root_objectid, u64 owner_objectid,
4379                                 u64 owner_offset, int refs_to_drop,
4380                                 struct btrfs_delayed_extent_op *extent_op)
4381 {
4382         struct btrfs_key key;
4383         struct btrfs_path *path;
4384         struct btrfs_fs_info *info = root->fs_info;
4385         struct btrfs_root *extent_root = info->extent_root;
4386         struct extent_buffer *leaf;
4387         struct btrfs_extent_item *ei;
4388         struct btrfs_extent_inline_ref *iref;
4389         int ret;
4390         int is_data;
4391         int extent_slot = 0;
4392         int found_extent = 0;
4393         int num_to_del = 1;
4394         u32 item_size;
4395         u64 refs;
4396
4397         path = btrfs_alloc_path();
4398         if (!path)
4399                 return -ENOMEM;
4400
4401         path->reada = 1;
4402         path->leave_spinning = 1;
4403
4404         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
4405         BUG_ON(!is_data && refs_to_drop != 1);
4406
4407         ret = lookup_extent_backref(trans, extent_root, path, &iref,
4408                                     bytenr, num_bytes, parent,
4409                                     root_objectid, owner_objectid,
4410                                     owner_offset);
4411         if (ret == 0) {
4412                 extent_slot = path->slots[0];
4413                 while (extent_slot >= 0) {
4414                         btrfs_item_key_to_cpu(path->nodes[0], &key,
4415                                               extent_slot);
4416                         if (key.objectid != bytenr)
4417                                 break;
4418                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
4419                             key.offset == num_bytes) {
4420                                 found_extent = 1;
4421                                 break;
4422                         }
4423                         if (path->slots[0] - extent_slot > 5)
4424                                 break;
4425                         extent_slot--;
4426                 }
4427 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4428                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
4429                 if (found_extent && item_size < sizeof(*ei))
4430                         found_extent = 0;
4431 #endif
4432                 if (!found_extent) {
4433                         BUG_ON(iref);
4434                         ret = remove_extent_backref(trans, extent_root, path,
4435                                                     NULL, refs_to_drop,
4436                                                     is_data);
4437                         BUG_ON(ret);
4438                         btrfs_release_path(path);
4439                         path->leave_spinning = 1;
4440
4441                         key.objectid = bytenr;
4442                         key.type = BTRFS_EXTENT_ITEM_KEY;
4443                         key.offset = num_bytes;
4444
4445                         ret = btrfs_search_slot(trans, extent_root,
4446                                                 &key, path, -1, 1);
4447                         if (ret) {
4448                                 printk(KERN_ERR "umm, got %d back from search"
4449                                        ", was looking for %llu\n", ret,
4450                                        (unsigned long long)bytenr);
4451                                 btrfs_print_leaf(extent_root, path->nodes[0]);
4452                         }
4453                         BUG_ON(ret);
4454                         extent_slot = path->slots[0];
4455                 }
4456         } else {
4457                 btrfs_print_leaf(extent_root, path->nodes[0]);
4458                 WARN_ON(1);
4459                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
4460                        "parent %llu root %llu  owner %llu offset %llu\n",
4461                        (unsigned long long)bytenr,
4462                        (unsigned long long)parent,
4463                        (unsigned long long)root_objectid,
4464                        (unsigned long long)owner_objectid,
4465                        (unsigned long long)owner_offset);
4466         }
4467
4468         leaf = path->nodes[0];
4469         item_size = btrfs_item_size_nr(leaf, extent_slot);
4470 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4471         if (item_size < sizeof(*ei)) {
4472                 BUG_ON(found_extent || extent_slot != path->slots[0]);
4473                 ret = convert_extent_item_v0(trans, extent_root, path,
4474                                              owner_objectid, 0);
4475                 BUG_ON(ret < 0);
4476
4477                 btrfs_release_path(path);
4478                 path->leave_spinning = 1;
4479
4480                 key.objectid = bytenr;
4481                 key.type = BTRFS_EXTENT_ITEM_KEY;
4482                 key.offset = num_bytes;
4483
4484                 ret = btrfs_search_slot(trans, extent_root, &key, path,
4485                                         -1, 1);
4486                 if (ret) {
4487                         printk(KERN_ERR "umm, got %d back from search"
4488                                ", was looking for %llu\n", ret,
4489                                (unsigned long long)bytenr);
4490                         btrfs_print_leaf(extent_root, path->nodes[0]);
4491                 }
4492                 BUG_ON(ret);
4493                 extent_slot = path->slots[0];
4494                 leaf = path->nodes[0];
4495                 item_size = btrfs_item_size_nr(leaf, extent_slot);
4496         }
4497 #endif
4498         BUG_ON(item_size < sizeof(*ei));
4499         ei = btrfs_item_ptr(leaf, extent_slot,
4500                             struct btrfs_extent_item);
4501         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4502                 struct btrfs_tree_block_info *bi;
4503                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
4504                 bi = (struct btrfs_tree_block_info *)(ei + 1);
4505                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
4506         }
4507
4508         refs = btrfs_extent_refs(leaf, ei);
4509         BUG_ON(refs < refs_to_drop);
4510         refs -= refs_to_drop;
4511
4512         if (refs > 0) {
4513                 if (extent_op)
4514                         __run_delayed_extent_op(extent_op, leaf, ei);
4515                 /*
4516                  * In the case of inline back ref, reference count will
4517                  * be updated by remove_extent_backref
4518                  */
4519                 if (iref) {
4520                         BUG_ON(!found_extent);
4521                 } else {
4522                         btrfs_set_extent_refs(leaf, ei, refs);
4523                         btrfs_mark_buffer_dirty(leaf);
4524                 }
4525                 if (found_extent) {
4526                         ret = remove_extent_backref(trans, extent_root, path,
4527                                                     iref, refs_to_drop,
4528                                                     is_data);
4529                         BUG_ON(ret);
4530                 }
4531         } else {
4532                 if (found_extent) {
4533                         BUG_ON(is_data && refs_to_drop !=
4534                                extent_data_ref_count(root, path, iref));
4535                         if (iref) {
4536                                 BUG_ON(path->slots[0] != extent_slot);
4537                         } else {
4538                                 BUG_ON(path->slots[0] != extent_slot + 1);
4539                                 path->slots[0] = extent_slot;
4540                                 num_to_del = 2;
4541                         }
4542                 }
4543
4544                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
4545                                       num_to_del);
4546                 BUG_ON(ret);
4547                 btrfs_release_path(path);
4548
4549                 if (is_data) {
4550                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
4551                         BUG_ON(ret);
4552                 } else {
4553                         invalidate_mapping_pages(info->btree_inode->i_mapping,
4554                              bytenr >> PAGE_CACHE_SHIFT,
4555                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
4556                 }
4557
4558                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
4559                 BUG_ON(ret);
4560         }
4561         btrfs_free_path(path);
4562         return ret;
4563 }
4564
4565 /*
4566  * when we free an block, it is possible (and likely) that we free the last
4567  * delayed ref for that extent as well.  This searches the delayed ref tree for
4568  * a given extent, and if there are no other delayed refs to be processed, it
4569  * removes it from the tree.
4570  */
4571 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
4572                                       struct btrfs_root *root, u64 bytenr)
4573 {
4574         struct btrfs_delayed_ref_head *head;
4575         struct btrfs_delayed_ref_root *delayed_refs;
4576         struct btrfs_delayed_ref_node *ref;
4577         struct rb_node *node;
4578         int ret = 0;
4579
4580         delayed_refs = &trans->transaction->delayed_refs;
4581         spin_lock(&delayed_refs->lock);
4582         head = btrfs_find_delayed_ref_head(trans, bytenr);
4583         if (!head)
4584                 goto out;
4585
4586         node = rb_prev(&head->node.rb_node);
4587         if (!node)
4588                 goto out;
4589
4590         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
4591
4592         /* there are still entries for this ref, we can't drop it */
4593         if (ref->bytenr == bytenr)
4594                 goto out;
4595
4596         if (head->extent_op) {
4597                 if (!head->must_insert_reserved)
4598                         goto out;
4599                 kfree(head->extent_op);
4600                 head->extent_op = NULL;
4601         }
4602
4603         /*
4604          * waiting for the lock here would deadlock.  If someone else has it
4605          * locked they are already in the process of dropping it anyway
4606          */
4607         if (!mutex_trylock(&head->mutex))
4608                 goto out;
4609
4610         /*
4611          * at this point we have a head with no other entries.  Go
4612          * ahead and process it.
4613          */
4614         head->node.in_tree = 0;
4615         rb_erase(&head->node.rb_node, &delayed_refs->root);
4616
4617         delayed_refs->num_entries--;
4618
4619         /*
4620          * we don't take a ref on the node because we're removing it from the
4621          * tree, so we just steal the ref the tree was holding.
4622          */
4623         delayed_refs->num_heads--;
4624         if (list_empty(&head->cluster))
4625                 delayed_refs->num_heads_ready--;
4626
4627         list_del_init(&head->cluster);
4628         spin_unlock(&delayed_refs->lock);
4629
4630         BUG_ON(head->extent_op);
4631         if (head->must_insert_reserved)
4632                 ret = 1;
4633
4634         mutex_unlock(&head->mutex);
4635         btrfs_put_delayed_ref(&head->node);
4636         return ret;
4637 out:
4638         spin_unlock(&delayed_refs->lock);
4639         return 0;
4640 }
4641
4642 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
4643                            struct btrfs_root *root,
4644                            struct extent_buffer *buf,
4645                            u64 parent, int last_ref)
4646 {
4647         struct btrfs_block_rsv *block_rsv;
4648         struct btrfs_block_group_cache *cache = NULL;
4649         int ret;
4650
4651         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4652                 ret = btrfs_add_delayed_tree_ref(trans, buf->start, buf->len,
4653                                                 parent, root->root_key.objectid,
4654                                                 btrfs_header_level(buf),
4655                                                 BTRFS_DROP_DELAYED_REF, NULL);
4656                 BUG_ON(ret);
4657         }
4658
4659         if (!last_ref)
4660                 return;
4661
4662         block_rsv = get_block_rsv(trans, root);
4663         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
4664         if (block_rsv->space_info != cache->space_info)
4665                 goto out;
4666
4667         if (btrfs_header_generation(buf) == trans->transid) {
4668                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4669                         ret = check_ref_cleanup(trans, root, buf->start);
4670                         if (!ret)
4671                                 goto pin;
4672                 }
4673
4674                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
4675                         pin_down_extent(root, cache, buf->start, buf->len, 1);
4676                         goto pin;
4677                 }
4678
4679                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
4680
4681                 btrfs_add_free_space(cache, buf->start, buf->len);
4682                 ret = btrfs_update_reserved_bytes(cache, buf->len, 0, 0);
4683                 if (ret == -EAGAIN) {
4684                         /* block group became read-only */
4685                         btrfs_update_reserved_bytes(cache, buf->len, 0, 1);
4686                         goto out;
4687                 }
4688
4689                 ret = 1;
4690                 spin_lock(&block_rsv->lock);
4691                 if (block_rsv->reserved < block_rsv->size) {
4692                         block_rsv->reserved += buf->len;
4693                         ret = 0;
4694                 }
4695                 spin_unlock(&block_rsv->lock);
4696
4697                 if (ret) {
4698                         spin_lock(&cache->space_info->lock);
4699                         cache->space_info->bytes_reserved -= buf->len;
4700                         cache->space_info->reservation_progress++;
4701                         spin_unlock(&cache->space_info->lock);
4702                 }
4703                 goto out;
4704         }
4705 pin:
4706         if (block_rsv->durable && !cache->ro) {
4707                 ret = 0;
4708                 spin_lock(&cache->lock);
4709                 if (!cache->ro) {
4710                         cache->reserved_pinned += buf->len;
4711                         ret = 1;
4712                 }
4713                 spin_unlock(&cache->lock);
4714
4715                 if (ret) {
4716                         spin_lock(&block_rsv->lock);
4717                         block_rsv->freed[trans->transid & 0x1] += buf->len;
4718                         spin_unlock(&block_rsv->lock);
4719                 }
4720         }
4721 out:
4722         /*
4723          * Deleting the buffer, clear the corrupt flag since it doesn't matter
4724          * anymore.
4725          */
4726         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
4727         btrfs_put_block_group(cache);
4728 }
4729
4730 int btrfs_free_extent(struct btrfs_trans_handle *trans,
4731                       struct btrfs_root *root,
4732                       u64 bytenr, u64 num_bytes, u64 parent,
4733                       u64 root_objectid, u64 owner, u64 offset)
4734 {
4735         int ret;
4736
4737         /*
4738          * tree log blocks never actually go into the extent allocation
4739          * tree, just update pinning info and exit early.
4740          */
4741         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
4742                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
4743                 /* unlocks the pinned mutex */
4744                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
4745                 ret = 0;
4746         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
4747                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
4748                                         parent, root_objectid, (int)owner,
4749                                         BTRFS_DROP_DELAYED_REF, NULL);
4750                 BUG_ON(ret);
4751         } else {
4752                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
4753                                         parent, root_objectid, owner,
4754                                         offset, BTRFS_DROP_DELAYED_REF, NULL);
4755                 BUG_ON(ret);
4756         }
4757         return ret;
4758 }
4759
4760 static u64 stripe_align(struct btrfs_root *root, u64 val)
4761 {
4762         u64 mask = ((u64)root->stripesize - 1);
4763         u64 ret = (val + mask) & ~mask;
4764         return ret;
4765 }
4766
4767 /*
4768  * when we wait for progress in the block group caching, its because
4769  * our allocation attempt failed at least once.  So, we must sleep
4770  * and let some progress happen before we try again.
4771  *
4772  * This function will sleep at least once waiting for new free space to
4773  * show up, and then it will check the block group free space numbers
4774  * for our min num_bytes.  Another option is to have it go ahead
4775  * and look in the rbtree for a free extent of a given size, but this
4776  * is a good start.
4777  */
4778 static noinline int
4779 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
4780                                 u64 num_bytes)
4781 {
4782         struct btrfs_caching_control *caching_ctl;
4783         DEFINE_WAIT(wait);
4784
4785         caching_ctl = get_caching_control(cache);
4786         if (!caching_ctl)
4787                 return 0;
4788
4789         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
4790                    (cache->free_space_ctl->free_space >= num_bytes));
4791
4792         put_caching_control(caching_ctl);
4793         return 0;
4794 }
4795
4796 static noinline int
4797 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
4798 {
4799         struct btrfs_caching_control *caching_ctl;
4800         DEFINE_WAIT(wait);
4801
4802         caching_ctl = get_caching_control(cache);
4803         if (!caching_ctl)
4804                 return 0;
4805
4806         wait_event(caching_ctl->wait, block_group_cache_done(cache));
4807
4808         put_caching_control(caching_ctl);
4809         return 0;
4810 }
4811
4812 static int get_block_group_index(struct btrfs_block_group_cache *cache)
4813 {
4814         int index;
4815         if (cache->flags & BTRFS_BLOCK_GROUP_RAID10)
4816                 index = 0;
4817         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID1)
4818                 index = 1;
4819         else if (cache->flags & BTRFS_BLOCK_GROUP_DUP)
4820                 index = 2;
4821         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID0)
4822                 index = 3;
4823         else
4824                 index = 4;
4825         return index;
4826 }
4827
4828 enum btrfs_loop_type {
4829         LOOP_FIND_IDEAL = 0,
4830         LOOP_CACHING_NOWAIT = 1,
4831         LOOP_CACHING_WAIT = 2,
4832         LOOP_ALLOC_CHUNK = 3,
4833         LOOP_NO_EMPTY_SIZE = 4,
4834 };
4835
4836 /*
4837  * walks the btree of allocated extents and find a hole of a given size.
4838  * The key ins is changed to record the hole:
4839  * ins->objectid == block start
4840  * ins->flags = BTRFS_EXTENT_ITEM_KEY
4841  * ins->offset == number of blocks
4842  * Any available blocks before search_start are skipped.
4843  */
4844 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
4845                                      struct btrfs_root *orig_root,
4846                                      u64 num_bytes, u64 empty_size,
4847                                      u64 search_start, u64 search_end,
4848                                      u64 hint_byte, struct btrfs_key *ins,
4849                                      int data)
4850 {
4851         int ret = 0;
4852         struct btrfs_root *root = orig_root->fs_info->extent_root;
4853         struct btrfs_free_cluster *last_ptr = NULL;
4854         struct btrfs_block_group_cache *block_group = NULL;
4855         int empty_cluster = 2 * 1024 * 1024;
4856         int allowed_chunk_alloc = 0;
4857         int done_chunk_alloc = 0;
4858         struct btrfs_space_info *space_info;
4859         int last_ptr_loop = 0;
4860         int loop = 0;
4861         int index = 0;
4862         bool found_uncached_bg = false;
4863         bool failed_cluster_refill = false;
4864         bool failed_alloc = false;
4865         bool use_cluster = true;
4866         u64 ideal_cache_percent = 0;
4867         u64 ideal_cache_offset = 0;
4868
4869         WARN_ON(num_bytes < root->sectorsize);
4870         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
4871         ins->objectid = 0;
4872         ins->offset = 0;
4873
4874         space_info = __find_space_info(root->fs_info, data);
4875         if (!space_info) {
4876                 printk(KERN_ERR "No space info for %d\n", data);
4877                 return -ENOSPC;
4878         }
4879
4880         /*
4881          * If the space info is for both data and metadata it means we have a
4882          * small filesystem and we can't use the clustering stuff.
4883          */
4884         if (btrfs_mixed_space_info(space_info))
4885                 use_cluster = false;
4886
4887         if (orig_root->ref_cows || empty_size)
4888                 allowed_chunk_alloc = 1;
4889
4890         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
4891                 last_ptr = &root->fs_info->meta_alloc_cluster;
4892                 if (!btrfs_test_opt(root, SSD))
4893                         empty_cluster = 64 * 1024;
4894         }
4895
4896         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
4897             btrfs_test_opt(root, SSD)) {
4898                 last_ptr = &root->fs_info->data_alloc_cluster;
4899         }
4900
4901         if (last_ptr) {
4902                 spin_lock(&last_ptr->lock);
4903                 if (last_ptr->block_group)
4904                         hint_byte = last_ptr->window_start;
4905                 spin_unlock(&last_ptr->lock);
4906         }
4907
4908         search_start = max(search_start, first_logical_byte(root, 0));
4909         search_start = max(search_start, hint_byte);
4910
4911         if (!last_ptr)
4912                 empty_cluster = 0;
4913
4914         if (search_start == hint_byte) {
4915 ideal_cache:
4916                 block_group = btrfs_lookup_block_group(root->fs_info,
4917                                                        search_start);
4918                 /*
4919                  * we don't want to use the block group if it doesn't match our
4920                  * allocation bits, or if its not cached.
4921                  *
4922                  * However if we are re-searching with an ideal block group
4923                  * picked out then we don't care that the block group is cached.
4924                  */
4925                 if (block_group && block_group_bits(block_group, data) &&
4926                     (block_group->cached != BTRFS_CACHE_NO ||
4927                      search_start == ideal_cache_offset)) {
4928                         down_read(&space_info->groups_sem);
4929                         if (list_empty(&block_group->list) ||
4930                             block_group->ro) {
4931                                 /*
4932                                  * someone is removing this block group,
4933                                  * we can't jump into the have_block_group
4934                                  * target because our list pointers are not
4935                                  * valid
4936                                  */
4937                                 btrfs_put_block_group(block_group);
4938                                 up_read(&space_info->groups_sem);
4939                         } else {
4940                                 index = get_block_group_index(block_group);
4941                                 goto have_block_group;
4942                         }
4943                 } else if (block_group) {
4944                         btrfs_put_block_group(block_group);
4945                 }
4946         }
4947 search:
4948         down_read(&space_info->groups_sem);
4949         list_for_each_entry(block_group, &space_info->block_groups[index],
4950                             list) {
4951                 u64 offset;
4952                 int cached;
4953
4954                 btrfs_get_block_group(block_group);
4955                 search_start = block_group->key.objectid;
4956
4957                 /*
4958                  * this can happen if we end up cycling through all the
4959                  * raid types, but we want to make sure we only allocate
4960                  * for the proper type.
4961                  */
4962                 if (!block_group_bits(block_group, data)) {
4963                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
4964                                 BTRFS_BLOCK_GROUP_RAID1 |
4965                                 BTRFS_BLOCK_GROUP_RAID10;
4966
4967                         /*
4968                          * if they asked for extra copies and this block group
4969                          * doesn't provide them, bail.  This does allow us to
4970                          * fill raid0 from raid1.
4971                          */
4972                         if ((data & extra) && !(block_group->flags & extra))
4973                                 goto loop;
4974                 }
4975
4976 have_block_group:
4977                 if (unlikely(block_group->cached == BTRFS_CACHE_NO)) {
4978                         u64 free_percent;
4979
4980                         ret = cache_block_group(block_group, trans,
4981                                                 orig_root, 1);
4982                         if (block_group->cached == BTRFS_CACHE_FINISHED)
4983                                 goto have_block_group;
4984
4985                         free_percent = btrfs_block_group_used(&block_group->item);
4986                         free_percent *= 100;
4987                         free_percent = div64_u64(free_percent,
4988                                                  block_group->key.offset);
4989                         free_percent = 100 - free_percent;
4990                         if (free_percent > ideal_cache_percent &&
4991                             likely(!block_group->ro)) {
4992                                 ideal_cache_offset = block_group->key.objectid;
4993                                 ideal_cache_percent = free_percent;
4994                         }
4995
4996                         /*
4997                          * We only want to start kthread caching if we are at
4998                          * the point where we will wait for caching to make
4999                          * progress, or if our ideal search is over and we've
5000                          * found somebody to start caching.
5001                          */
5002                         if (loop > LOOP_CACHING_NOWAIT ||
5003                             (loop > LOOP_FIND_IDEAL &&
5004                              atomic_read(&space_info->caching_threads) < 2)) {
5005                                 ret = cache_block_group(block_group, trans,
5006                                                         orig_root, 0);
5007                                 BUG_ON(ret);
5008                         }
5009                         found_uncached_bg = true;
5010
5011                         /*
5012                          * If loop is set for cached only, try the next block
5013                          * group.
5014                          */
5015                         if (loop == LOOP_FIND_IDEAL)
5016                                 goto loop;
5017                 }
5018
5019                 cached = block_group_cache_done(block_group);
5020                 if (unlikely(!cached))
5021                         found_uncached_bg = true;
5022
5023                 if (unlikely(block_group->ro))
5024                         goto loop;
5025
5026                 spin_lock(&block_group->free_space_ctl->tree_lock);
5027                 if (cached &&
5028                     block_group->free_space_ctl->free_space <
5029                     num_bytes + empty_size) {
5030                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5031                         goto loop;
5032                 }
5033                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5034
5035                 /*
5036                  * Ok we want to try and use the cluster allocator, so lets look
5037                  * there, unless we are on LOOP_NO_EMPTY_SIZE, since we will
5038                  * have tried the cluster allocator plenty of times at this
5039                  * point and not have found anything, so we are likely way too
5040                  * fragmented for the clustering stuff to find anything, so lets
5041                  * just skip it and let the allocator find whatever block it can
5042                  * find
5043                  */
5044                 if (last_ptr && loop < LOOP_NO_EMPTY_SIZE) {
5045                         /*
5046                          * the refill lock keeps out other
5047                          * people trying to start a new cluster
5048                          */
5049                         spin_lock(&last_ptr->refill_lock);
5050                         if (last_ptr->block_group &&
5051                             (last_ptr->block_group->ro ||
5052                             !block_group_bits(last_ptr->block_group, data))) {
5053                                 offset = 0;
5054                                 goto refill_cluster;
5055                         }
5056
5057                         offset = btrfs_alloc_from_cluster(block_group, last_ptr,
5058                                                  num_bytes, search_start);
5059                         if (offset) {
5060                                 /* we have a block, we're done */
5061                                 spin_unlock(&last_ptr->refill_lock);
5062                                 goto checks;
5063                         }
5064
5065                         spin_lock(&last_ptr->lock);
5066                         /*
5067                          * whoops, this cluster doesn't actually point to
5068                          * this block group.  Get a ref on the block
5069                          * group is does point to and try again
5070                          */
5071                         if (!last_ptr_loop && last_ptr->block_group &&
5072                             last_ptr->block_group != block_group) {
5073
5074                                 btrfs_put_block_group(block_group);
5075                                 block_group = last_ptr->block_group;
5076                                 btrfs_get_block_group(block_group);
5077                                 spin_unlock(&last_ptr->lock);
5078                                 spin_unlock(&last_ptr->refill_lock);
5079
5080                                 last_ptr_loop = 1;
5081                                 search_start = block_group->key.objectid;
5082                                 /*
5083                                  * we know this block group is properly
5084                                  * in the list because
5085                                  * btrfs_remove_block_group, drops the
5086                                  * cluster before it removes the block
5087                                  * group from the list
5088                                  */
5089                                 goto have_block_group;
5090                         }
5091                         spin_unlock(&last_ptr->lock);
5092 refill_cluster:
5093                         /*
5094                          * this cluster didn't work out, free it and
5095                          * start over
5096                          */
5097                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5098
5099                         last_ptr_loop = 0;
5100
5101                         /* allocate a cluster in this block group */
5102                         ret = btrfs_find_space_cluster(trans, root,
5103                                                block_group, last_ptr,
5104                                                offset, num_bytes,
5105                                                empty_cluster + empty_size);
5106                         if (ret == 0) {
5107                                 /*
5108                                  * now pull our allocation out of this
5109                                  * cluster
5110                                  */
5111                                 offset = btrfs_alloc_from_cluster(block_group,
5112                                                   last_ptr, num_bytes,
5113                                                   search_start);
5114                                 if (offset) {
5115                                         /* we found one, proceed */
5116                                         spin_unlock(&last_ptr->refill_lock);
5117                                         goto checks;
5118                                 }
5119                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5120                                    && !failed_cluster_refill) {
5121                                 spin_unlock(&last_ptr->refill_lock);
5122
5123                                 failed_cluster_refill = true;
5124                                 wait_block_group_cache_progress(block_group,
5125                                        num_bytes + empty_cluster + empty_size);
5126                                 goto have_block_group;
5127                         }
5128
5129                         /*
5130                          * at this point we either didn't find a cluster
5131                          * or we weren't able to allocate a block from our
5132                          * cluster.  Free the cluster we've been trying
5133                          * to use, and go to the next block group
5134                          */
5135                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5136                         spin_unlock(&last_ptr->refill_lock);
5137                         goto loop;
5138                 }
5139
5140                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5141                                                     num_bytes, empty_size);
5142                 /*
5143                  * If we didn't find a chunk, and we haven't failed on this
5144                  * block group before, and this block group is in the middle of
5145                  * caching and we are ok with waiting, then go ahead and wait
5146                  * for progress to be made, and set failed_alloc to true.
5147                  *
5148                  * If failed_alloc is true then we've already waited on this
5149                  * block group once and should move on to the next block group.
5150                  */
5151                 if (!offset && !failed_alloc && !cached &&
5152                     loop > LOOP_CACHING_NOWAIT) {
5153                         wait_block_group_cache_progress(block_group,
5154                                                 num_bytes + empty_size);
5155                         failed_alloc = true;
5156                         goto have_block_group;
5157                 } else if (!offset) {
5158                         goto loop;
5159                 }
5160 checks:
5161                 search_start = stripe_align(root, offset);
5162                 /* move on to the next group */
5163                 if (search_start + num_bytes >= search_end) {
5164                         btrfs_add_free_space(block_group, offset, num_bytes);
5165                         goto loop;
5166                 }
5167
5168                 /* move on to the next group */
5169                 if (search_start + num_bytes >
5170                     block_group->key.objectid + block_group->key.offset) {
5171                         btrfs_add_free_space(block_group, offset, num_bytes);
5172                         goto loop;
5173                 }
5174
5175                 ins->objectid = search_start;
5176                 ins->offset = num_bytes;
5177
5178                 if (offset < search_start)
5179                         btrfs_add_free_space(block_group, offset,
5180                                              search_start - offset);
5181                 BUG_ON(offset > search_start);
5182
5183                 ret = btrfs_update_reserved_bytes(block_group, num_bytes, 1,
5184                                             (data & BTRFS_BLOCK_GROUP_DATA));
5185                 if (ret == -EAGAIN) {
5186                         btrfs_add_free_space(block_group, offset, num_bytes);
5187                         goto loop;
5188                 }
5189
5190                 /* we are all good, lets return */
5191                 ins->objectid = search_start;
5192                 ins->offset = num_bytes;
5193
5194                 if (offset < search_start)
5195                         btrfs_add_free_space(block_group, offset,
5196                                              search_start - offset);
5197                 BUG_ON(offset > search_start);
5198                 btrfs_put_block_group(block_group);
5199                 break;
5200 loop:
5201                 failed_cluster_refill = false;
5202                 failed_alloc = false;
5203                 BUG_ON(index != get_block_group_index(block_group));
5204                 btrfs_put_block_group(block_group);
5205         }
5206         up_read(&space_info->groups_sem);
5207
5208         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5209                 goto search;
5210
5211         /* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
5212          *                      for them to make caching progress.  Also
5213          *                      determine the best possible bg to cache
5214          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5215          *                      caching kthreads as we move along
5216          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5217          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5218          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5219          *                      again
5220          */
5221         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5222                 index = 0;
5223                 if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
5224                         found_uncached_bg = false;
5225                         loop++;
5226                         if (!ideal_cache_percent &&
5227                             atomic_read(&space_info->caching_threads))
5228                                 goto search;
5229
5230                         /*
5231                          * 1 of the following 2 things have happened so far
5232                          *
5233                          * 1) We found an ideal block group for caching that
5234                          * is mostly full and will cache quickly, so we might
5235                          * as well wait for it.
5236                          *
5237                          * 2) We searched for cached only and we didn't find
5238                          * anything, and we didn't start any caching kthreads
5239                          * either, so chances are we will loop through and
5240                          * start a couple caching kthreads, and then come back
5241                          * around and just wait for them.  This will be slower
5242                          * because we will have 2 caching kthreads reading at
5243                          * the same time when we could have just started one
5244                          * and waited for it to get far enough to give us an
5245                          * allocation, so go ahead and go to the wait caching
5246                          * loop.
5247                          */
5248                         loop = LOOP_CACHING_WAIT;
5249                         search_start = ideal_cache_offset;
5250                         ideal_cache_percent = 0;
5251                         goto ideal_cache;
5252                 } else if (loop == LOOP_FIND_IDEAL) {
5253                         /*
5254                          * Didn't find a uncached bg, wait on anything we find
5255                          * next.
5256                          */
5257                         loop = LOOP_CACHING_WAIT;
5258                         goto search;
5259                 }
5260
5261                 loop++;
5262
5263                 if (loop == LOOP_ALLOC_CHUNK) {
5264                        if (allowed_chunk_alloc) {
5265                                 ret = do_chunk_alloc(trans, root, num_bytes +
5266                                                      2 * 1024 * 1024, data,
5267                                                      CHUNK_ALLOC_LIMITED);
5268                                 allowed_chunk_alloc = 0;
5269                                 if (ret == 1)
5270                                         done_chunk_alloc = 1;
5271                         } else if (!done_chunk_alloc &&
5272                                    space_info->force_alloc ==
5273                                    CHUNK_ALLOC_NO_FORCE) {
5274                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5275                         }
5276
5277                        /*
5278                         * We didn't allocate a chunk, go ahead and drop the
5279                         * empty size and loop again.
5280                         */
5281                        if (!done_chunk_alloc)
5282                                loop = LOOP_NO_EMPTY_SIZE;
5283                 }
5284
5285                 if (loop == LOOP_NO_EMPTY_SIZE) {
5286                         empty_size = 0;
5287                         empty_cluster = 0;
5288                 }
5289
5290                 goto search;
5291         } else if (!ins->objectid) {
5292                 ret = -ENOSPC;
5293         } else if (ins->objectid) {
5294                 ret = 0;
5295         }
5296
5297         return ret;
5298 }
5299
5300 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5301                             int dump_block_groups)
5302 {
5303         struct btrfs_block_group_cache *cache;
5304         int index = 0;
5305
5306         spin_lock(&info->lock);
5307         printk(KERN_INFO "space_info has %llu free, is %sfull\n",
5308                (unsigned long long)(info->total_bytes - info->bytes_used -
5309                                     info->bytes_pinned - info->bytes_reserved -
5310                                     info->bytes_readonly),
5311                (info->full) ? "" : "not ");
5312         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5313                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5314                (unsigned long long)info->total_bytes,
5315                (unsigned long long)info->bytes_used,
5316                (unsigned long long)info->bytes_pinned,
5317                (unsigned long long)info->bytes_reserved,
5318                (unsigned long long)info->bytes_may_use,
5319                (unsigned long long)info->bytes_readonly);
5320         spin_unlock(&info->lock);
5321
5322         if (!dump_block_groups)
5323                 return;
5324
5325         down_read(&info->groups_sem);
5326 again:
5327         list_for_each_entry(cache, &info->block_groups[index], list) {
5328                 spin_lock(&cache->lock);
5329                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
5330                        "%llu pinned %llu reserved\n",
5331                        (unsigned long long)cache->key.objectid,
5332                        (unsigned long long)cache->key.offset,
5333                        (unsigned long long)btrfs_block_group_used(&cache->item),
5334                        (unsigned long long)cache->pinned,
5335                        (unsigned long long)cache->reserved);
5336                 btrfs_dump_free_space(cache, bytes);
5337                 spin_unlock(&cache->lock);
5338         }
5339         if (++index < BTRFS_NR_RAID_TYPES)
5340                 goto again;
5341         up_read(&info->groups_sem);
5342 }
5343
5344 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5345                          struct btrfs_root *root,
5346                          u64 num_bytes, u64 min_alloc_size,
5347                          u64 empty_size, u64 hint_byte,
5348                          u64 search_end, struct btrfs_key *ins,
5349                          u64 data)
5350 {
5351         int ret;
5352         u64 search_start = 0;
5353
5354         data = btrfs_get_alloc_profile(root, data);
5355 again:
5356         /*
5357          * the only place that sets empty_size is btrfs_realloc_node, which
5358          * is not called recursively on allocations
5359          */
5360         if (empty_size || root->ref_cows)
5361                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5362                                      num_bytes + 2 * 1024 * 1024, data,
5363                                      CHUNK_ALLOC_NO_FORCE);
5364
5365         WARN_ON(num_bytes < root->sectorsize);
5366         ret = find_free_extent(trans, root, num_bytes, empty_size,
5367                                search_start, search_end, hint_byte,
5368                                ins, data);
5369
5370         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
5371                 num_bytes = num_bytes >> 1;
5372                 num_bytes = num_bytes & ~(root->sectorsize - 1);
5373                 num_bytes = max(num_bytes, min_alloc_size);
5374                 do_chunk_alloc(trans, root->fs_info->extent_root,
5375                                num_bytes, data, CHUNK_ALLOC_FORCE);
5376                 goto again;
5377         }
5378         if (ret == -ENOSPC && btrfs_test_opt(root, ENOSPC_DEBUG)) {
5379                 struct btrfs_space_info *sinfo;
5380
5381                 sinfo = __find_space_info(root->fs_info, data);
5382                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
5383                        "wanted %llu\n", (unsigned long long)data,
5384                        (unsigned long long)num_bytes);
5385                 dump_space_info(sinfo, num_bytes, 1);
5386         }
5387
5388         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5389
5390         return ret;
5391 }
5392
5393 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
5394 {
5395         struct btrfs_block_group_cache *cache;
5396         int ret = 0;
5397
5398         cache = btrfs_lookup_block_group(root->fs_info, start);
5399         if (!cache) {
5400                 printk(KERN_ERR "Unable to find block group for %llu\n",
5401                        (unsigned long long)start);
5402                 return -ENOSPC;
5403         }
5404
5405         if (btrfs_test_opt(root, DISCARD))
5406                 ret = btrfs_discard_extent(root, start, len, NULL);
5407
5408         btrfs_add_free_space(cache, start, len);
5409         btrfs_update_reserved_bytes(cache, len, 0, 1);
5410         btrfs_put_block_group(cache);
5411
5412         trace_btrfs_reserved_extent_free(root, start, len);
5413
5414         return ret;
5415 }
5416
5417 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5418                                       struct btrfs_root *root,
5419                                       u64 parent, u64 root_objectid,
5420                                       u64 flags, u64 owner, u64 offset,
5421                                       struct btrfs_key *ins, int ref_mod)
5422 {
5423         int ret;
5424         struct btrfs_fs_info *fs_info = root->fs_info;
5425         struct btrfs_extent_item *extent_item;
5426         struct btrfs_extent_inline_ref *iref;
5427         struct btrfs_path *path;
5428         struct extent_buffer *leaf;
5429         int type;
5430         u32 size;
5431
5432         if (parent > 0)
5433                 type = BTRFS_SHARED_DATA_REF_KEY;
5434         else
5435                 type = BTRFS_EXTENT_DATA_REF_KEY;
5436
5437         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
5438
5439         path = btrfs_alloc_path();
5440         if (!path)
5441                 return -ENOMEM;
5442
5443         path->leave_spinning = 1;
5444         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5445                                       ins, size);
5446         BUG_ON(ret);
5447
5448         leaf = path->nodes[0];
5449         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5450                                      struct btrfs_extent_item);
5451         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
5452         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5453         btrfs_set_extent_flags(leaf, extent_item,
5454                                flags | BTRFS_EXTENT_FLAG_DATA);
5455
5456         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
5457         btrfs_set_extent_inline_ref_type(leaf, iref, type);
5458         if (parent > 0) {
5459                 struct btrfs_shared_data_ref *ref;
5460                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
5461                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5462                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
5463         } else {
5464                 struct btrfs_extent_data_ref *ref;
5465                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
5466                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
5467                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
5468                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
5469                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
5470         }
5471
5472         btrfs_mark_buffer_dirty(path->nodes[0]);
5473         btrfs_free_path(path);
5474
5475         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5476         if (ret) {
5477                 printk(KERN_ERR "btrfs update block group failed for %llu "
5478                        "%llu\n", (unsigned long long)ins->objectid,
5479                        (unsigned long long)ins->offset);
5480                 BUG();
5481         }
5482         return ret;
5483 }
5484
5485 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
5486                                      struct btrfs_root *root,
5487                                      u64 parent, u64 root_objectid,
5488                                      u64 flags, struct btrfs_disk_key *key,
5489                                      int level, struct btrfs_key *ins)
5490 {
5491         int ret;
5492         struct btrfs_fs_info *fs_info = root->fs_info;
5493         struct btrfs_extent_item *extent_item;
5494         struct btrfs_tree_block_info *block_info;
5495         struct btrfs_extent_inline_ref *iref;
5496         struct btrfs_path *path;
5497         struct extent_buffer *leaf;
5498         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
5499
5500         path = btrfs_alloc_path();
5501         BUG_ON(!path);
5502
5503         path->leave_spinning = 1;
5504         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5505                                       ins, size);
5506         BUG_ON(ret);
5507
5508         leaf = path->nodes[0];
5509         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5510                                      struct btrfs_extent_item);
5511         btrfs_set_extent_refs(leaf, extent_item, 1);
5512         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5513         btrfs_set_extent_flags(leaf, extent_item,
5514                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
5515         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
5516
5517         btrfs_set_tree_block_key(leaf, block_info, key);
5518         btrfs_set_tree_block_level(leaf, block_info, level);
5519
5520         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
5521         if (parent > 0) {
5522                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
5523                 btrfs_set_extent_inline_ref_type(leaf, iref,
5524                                                  BTRFS_SHARED_BLOCK_REF_KEY);
5525                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5526         } else {
5527                 btrfs_set_extent_inline_ref_type(leaf, iref,
5528                                                  BTRFS_TREE_BLOCK_REF_KEY);
5529                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
5530         }
5531
5532         btrfs_mark_buffer_dirty(leaf);
5533         btrfs_free_path(path);
5534
5535         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5536         if (ret) {
5537                 printk(KERN_ERR "btrfs update block group failed for %llu "
5538                        "%llu\n", (unsigned long long)ins->objectid,
5539                        (unsigned long long)ins->offset);
5540                 BUG();
5541         }
5542         return ret;
5543 }
5544
5545 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5546                                      struct btrfs_root *root,
5547                                      u64 root_objectid, u64 owner,
5548                                      u64 offset, struct btrfs_key *ins)
5549 {
5550         int ret;
5551
5552         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
5553
5554         ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
5555                                          0, root_objectid, owner, offset,
5556                                          BTRFS_ADD_DELAYED_EXTENT, NULL);
5557         return ret;
5558 }
5559
5560 /*
5561  * this is used by the tree logging recovery code.  It records that
5562  * an extent has been allocated and makes sure to clear the free
5563  * space cache bits as well
5564  */
5565 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
5566                                    struct btrfs_root *root,
5567                                    u64 root_objectid, u64 owner, u64 offset,
5568                                    struct btrfs_key *ins)
5569 {
5570         int ret;
5571         struct btrfs_block_group_cache *block_group;
5572         struct btrfs_caching_control *caching_ctl;
5573         u64 start = ins->objectid;
5574         u64 num_bytes = ins->offset;
5575
5576         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
5577         cache_block_group(block_group, trans, NULL, 0);
5578         caching_ctl = get_caching_control(block_group);
5579
5580         if (!caching_ctl) {
5581                 BUG_ON(!block_group_cache_done(block_group));
5582                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5583                 BUG_ON(ret);
5584         } else {
5585                 mutex_lock(&caching_ctl->mutex);
5586
5587                 if (start >= caching_ctl->progress) {
5588                         ret = add_excluded_extent(root, start, num_bytes);
5589                         BUG_ON(ret);
5590                 } else if (start + num_bytes <= caching_ctl->progress) {
5591                         ret = btrfs_remove_free_space(block_group,
5592                                                       start, num_bytes);
5593                         BUG_ON(ret);
5594                 } else {
5595                         num_bytes = caching_ctl->progress - start;
5596                         ret = btrfs_remove_free_space(block_group,
5597                                                       start, num_bytes);
5598                         BUG_ON(ret);
5599
5600                         start = caching_ctl->progress;
5601                         num_bytes = ins->objectid + ins->offset -
5602                                     caching_ctl->progress;
5603                         ret = add_excluded_extent(root, start, num_bytes);
5604                         BUG_ON(ret);
5605                 }
5606
5607                 mutex_unlock(&caching_ctl->mutex);
5608                 put_caching_control(caching_ctl);
5609         }
5610
5611         ret = btrfs_update_reserved_bytes(block_group, ins->offset, 1, 1);
5612         BUG_ON(ret);
5613         btrfs_put_block_group(block_group);
5614         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
5615                                          0, owner, offset, ins, 1);
5616         return ret;
5617 }
5618
5619 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
5620                                             struct btrfs_root *root,
5621                                             u64 bytenr, u32 blocksize,
5622                                             int level)
5623 {
5624         struct extent_buffer *buf;
5625
5626         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
5627         if (!buf)
5628                 return ERR_PTR(-ENOMEM);
5629         btrfs_set_header_generation(buf, trans->transid);
5630         btrfs_set_buffer_lockdep_class(buf, level);
5631         btrfs_tree_lock(buf);
5632         clean_tree_block(trans, root, buf);
5633
5634         btrfs_set_lock_blocking(buf);
5635         btrfs_set_buffer_uptodate(buf);
5636
5637         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
5638                 /*
5639                  * we allow two log transactions at a time, use different
5640                  * EXENT bit to differentiate dirty pages.
5641                  */
5642                 if (root->log_transid % 2 == 0)
5643                         set_extent_dirty(&root->dirty_log_pages, buf->start,
5644                                         buf->start + buf->len - 1, GFP_NOFS);
5645                 else
5646                         set_extent_new(&root->dirty_log_pages, buf->start,
5647                                         buf->start + buf->len - 1, GFP_NOFS);
5648         } else {
5649                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
5650                          buf->start + buf->len - 1, GFP_NOFS);
5651         }
5652         trans->blocks_used++;
5653         /* this returns a buffer locked for blocking */
5654         return buf;
5655 }
5656
5657 static struct btrfs_block_rsv *
5658 use_block_rsv(struct btrfs_trans_handle *trans,
5659               struct btrfs_root *root, u32 blocksize)
5660 {
5661         struct btrfs_block_rsv *block_rsv;
5662         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5663         int ret;
5664
5665         block_rsv = get_block_rsv(trans, root);
5666
5667         if (block_rsv->size == 0) {
5668                 ret = reserve_metadata_bytes(trans, root, block_rsv,
5669                                              blocksize, 0);
5670                 /*
5671                  * If we couldn't reserve metadata bytes try and use some from
5672                  * the global reserve.
5673                  */
5674                 if (ret && block_rsv != global_rsv) {
5675                         ret = block_rsv_use_bytes(global_rsv, blocksize);
5676                         if (!ret)
5677                                 return global_rsv;
5678                         return ERR_PTR(ret);
5679                 } else if (ret) {
5680                         return ERR_PTR(ret);
5681                 }
5682                 return block_rsv;
5683         }
5684
5685         ret = block_rsv_use_bytes(block_rsv, blocksize);
5686         if (!ret)
5687                 return block_rsv;
5688         if (ret) {
5689                 WARN_ON(1);
5690                 ret = reserve_metadata_bytes(trans, root, block_rsv, blocksize,
5691                                              0);
5692                 if (!ret) {
5693                         spin_lock(&block_rsv->lock);
5694                         block_rsv->size += blocksize;
5695                         spin_unlock(&block_rsv->lock);
5696                         return block_rsv;
5697                 } else if (ret && block_rsv != global_rsv) {
5698                         ret = block_rsv_use_bytes(global_rsv, blocksize);
5699                         if (!ret)
5700                                 return global_rsv;
5701                 }
5702         }
5703
5704         return ERR_PTR(-ENOSPC);
5705 }
5706
5707 static void unuse_block_rsv(struct btrfs_block_rsv *block_rsv, u32 blocksize)
5708 {
5709         block_rsv_add_bytes(block_rsv, blocksize, 0);
5710         block_rsv_release_bytes(block_rsv, NULL, 0);
5711 }
5712
5713 /*
5714  * finds a free extent and does all the dirty work required for allocation
5715  * returns the key for the extent through ins, and a tree buffer for
5716  * the first block of the extent through buf.
5717  *
5718  * returns the tree buffer or NULL.
5719  */
5720 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
5721                                         struct btrfs_root *root, u32 blocksize,
5722                                         u64 parent, u64 root_objectid,
5723                                         struct btrfs_disk_key *key, int level,
5724                                         u64 hint, u64 empty_size)
5725 {
5726         struct btrfs_key ins;
5727         struct btrfs_block_rsv *block_rsv;
5728         struct extent_buffer *buf;
5729         u64 flags = 0;
5730         int ret;
5731
5732
5733         block_rsv = use_block_rsv(trans, root, blocksize);
5734         if (IS_ERR(block_rsv))
5735                 return ERR_CAST(block_rsv);
5736
5737         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
5738                                    empty_size, hint, (u64)-1, &ins, 0);
5739         if (ret) {
5740                 unuse_block_rsv(block_rsv, blocksize);
5741                 return ERR_PTR(ret);
5742         }
5743
5744         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
5745                                     blocksize, level);
5746         BUG_ON(IS_ERR(buf));
5747
5748         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
5749                 if (parent == 0)
5750                         parent = ins.objectid;
5751                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
5752         } else
5753                 BUG_ON(parent > 0);
5754
5755         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
5756                 struct btrfs_delayed_extent_op *extent_op;
5757                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
5758                 BUG_ON(!extent_op);
5759                 if (key)
5760                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
5761                 else
5762                         memset(&extent_op->key, 0, sizeof(extent_op->key));
5763                 extent_op->flags_to_set = flags;
5764                 extent_op->update_key = 1;
5765                 extent_op->update_flags = 1;
5766                 extent_op->is_data = 0;
5767
5768                 ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
5769                                         ins.offset, parent, root_objectid,
5770                                         level, BTRFS_ADD_DELAYED_EXTENT,
5771                                         extent_op);
5772                 BUG_ON(ret);
5773         }
5774         return buf;
5775 }
5776
5777 struct walk_control {
5778         u64 refs[BTRFS_MAX_LEVEL];
5779         u64 flags[BTRFS_MAX_LEVEL];
5780         struct btrfs_key update_progress;
5781         int stage;
5782         int level;
5783         int shared_level;
5784         int update_ref;
5785         int keep_locks;
5786         int reada_slot;
5787         int reada_count;
5788 };
5789
5790 #define DROP_REFERENCE  1
5791 #define UPDATE_BACKREF  2
5792
5793 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
5794                                      struct btrfs_root *root,
5795                                      struct walk_control *wc,
5796                                      struct btrfs_path *path)
5797 {
5798         u64 bytenr;
5799         u64 generation;
5800         u64 refs;
5801         u64 flags;
5802         u32 nritems;
5803         u32 blocksize;
5804         struct btrfs_key key;
5805         struct extent_buffer *eb;
5806         int ret;
5807         int slot;
5808         int nread = 0;
5809
5810         if (path->slots[wc->level] < wc->reada_slot) {
5811                 wc->reada_count = wc->reada_count * 2 / 3;
5812                 wc->reada_count = max(wc->reada_count, 2);
5813         } else {
5814                 wc->reada_count = wc->reada_count * 3 / 2;
5815                 wc->reada_count = min_t(int, wc->reada_count,
5816                                         BTRFS_NODEPTRS_PER_BLOCK(root));
5817         }
5818
5819         eb = path->nodes[wc->level];
5820         nritems = btrfs_header_nritems(eb);
5821         blocksize = btrfs_level_size(root, wc->level - 1);
5822
5823         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
5824                 if (nread >= wc->reada_count)
5825                         break;
5826
5827                 cond_resched();
5828                 bytenr = btrfs_node_blockptr(eb, slot);
5829                 generation = btrfs_node_ptr_generation(eb, slot);
5830
5831                 if (slot == path->slots[wc->level])
5832                         goto reada;
5833
5834                 if (wc->stage == UPDATE_BACKREF &&
5835                     generation <= root->root_key.offset)
5836                         continue;
5837
5838                 /* We don't lock the tree block, it's OK to be racy here */
5839                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
5840                                                &refs, &flags);
5841                 BUG_ON(ret);
5842                 BUG_ON(refs == 0);
5843
5844                 if (wc->stage == DROP_REFERENCE) {
5845                         if (refs == 1)
5846                                 goto reada;
5847
5848                         if (wc->level == 1 &&
5849                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5850                                 continue;
5851                         if (!wc->update_ref ||
5852                             generation <= root->root_key.offset)
5853                                 continue;
5854                         btrfs_node_key_to_cpu(eb, &key, slot);
5855                         ret = btrfs_comp_cpu_keys(&key,
5856                                                   &wc->update_progress);
5857                         if (ret < 0)
5858                                 continue;
5859                 } else {
5860                         if (wc->level == 1 &&
5861                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5862                                 continue;
5863                 }
5864 reada:
5865                 ret = readahead_tree_block(root, bytenr, blocksize,
5866                                            generation);
5867                 if (ret)
5868                         break;
5869                 nread++;
5870         }
5871         wc->reada_slot = slot;
5872 }
5873
5874 /*
5875  * hepler to process tree block while walking down the tree.
5876  *
5877  * when wc->stage == UPDATE_BACKREF, this function updates
5878  * back refs for pointers in the block.
5879  *
5880  * NOTE: return value 1 means we should stop walking down.
5881  */
5882 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
5883                                    struct btrfs_root *root,
5884                                    struct btrfs_path *path,
5885                                    struct walk_control *wc, int lookup_info)
5886 {
5887         int level = wc->level;
5888         struct extent_buffer *eb = path->nodes[level];
5889         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5890         int ret;
5891
5892         if (wc->stage == UPDATE_BACKREF &&
5893             btrfs_header_owner(eb) != root->root_key.objectid)
5894                 return 1;
5895
5896         /*
5897          * when reference count of tree block is 1, it won't increase
5898          * again. once full backref flag is set, we never clear it.
5899          */
5900         if (lookup_info &&
5901             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
5902              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
5903                 BUG_ON(!path->locks[level]);
5904                 ret = btrfs_lookup_extent_info(trans, root,
5905                                                eb->start, eb->len,
5906                                                &wc->refs[level],
5907                                                &wc->flags[level]);
5908                 BUG_ON(ret);
5909                 BUG_ON(wc->refs[level] == 0);
5910         }
5911
5912         if (wc->stage == DROP_REFERENCE) {
5913                 if (wc->refs[level] > 1)
5914                         return 1;
5915
5916                 if (path->locks[level] && !wc->keep_locks) {
5917                         btrfs_tree_unlock(eb);
5918                         path->locks[level] = 0;
5919                 }
5920                 return 0;
5921         }
5922
5923         /* wc->stage == UPDATE_BACKREF */
5924         if (!(wc->flags[level] & flag)) {
5925                 BUG_ON(!path->locks[level]);
5926                 ret = btrfs_inc_ref(trans, root, eb, 1);
5927                 BUG_ON(ret);
5928                 ret = btrfs_dec_ref(trans, root, eb, 0);
5929                 BUG_ON(ret);
5930                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
5931                                                   eb->len, flag, 0);
5932                 BUG_ON(ret);
5933                 wc->flags[level] |= flag;
5934         }
5935
5936         /*
5937          * the block is shared by multiple trees, so it's not good to
5938          * keep the tree lock
5939          */
5940         if (path->locks[level] && level > 0) {
5941                 btrfs_tree_unlock(eb);
5942                 path->locks[level] = 0;
5943         }
5944         return 0;
5945 }
5946
5947 /*
5948  * hepler to process tree block pointer.
5949  *
5950  * when wc->stage == DROP_REFERENCE, this function checks
5951  * reference count of the block pointed to. if the block
5952  * is shared and we need update back refs for the subtree
5953  * rooted at the block, this function changes wc->stage to
5954  * UPDATE_BACKREF. if the block is shared and there is no
5955  * need to update back, this function drops the reference
5956  * to the block.
5957  *
5958  * NOTE: return value 1 means we should stop walking down.
5959  */
5960 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
5961                                  struct btrfs_root *root,
5962                                  struct btrfs_path *path,
5963                                  struct walk_control *wc, int *lookup_info)
5964 {
5965         u64 bytenr;
5966         u64 generation;
5967         u64 parent;
5968         u32 blocksize;
5969         struct btrfs_key key;
5970         struct extent_buffer *next;
5971         int level = wc->level;
5972         int reada = 0;
5973         int ret = 0;
5974
5975         generation = btrfs_node_ptr_generation(path->nodes[level],
5976                                                path->slots[level]);
5977         /*
5978          * if the lower level block was created before the snapshot
5979          * was created, we know there is no need to update back refs
5980          * for the subtree
5981          */
5982         if (wc->stage == UPDATE_BACKREF &&
5983             generation <= root->root_key.offset) {
5984                 *lookup_info = 1;
5985                 return 1;
5986         }
5987
5988         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
5989         blocksize = btrfs_level_size(root, level - 1);
5990
5991         next = btrfs_find_tree_block(root, bytenr, blocksize);
5992         if (!next) {
5993                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
5994                 if (!next)
5995                         return -ENOMEM;
5996                 reada = 1;
5997         }
5998         btrfs_tree_lock(next);
5999         btrfs_set_lock_blocking(next);
6000
6001         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6002                                        &wc->refs[level - 1],
6003                                        &wc->flags[level - 1]);
6004         BUG_ON(ret);
6005         BUG_ON(wc->refs[level - 1] == 0);
6006         *lookup_info = 0;
6007
6008         if (wc->stage == DROP_REFERENCE) {
6009                 if (wc->refs[level - 1] > 1) {
6010                         if (level == 1 &&
6011                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6012                                 goto skip;
6013
6014                         if (!wc->update_ref ||
6015                             generation <= root->root_key.offset)
6016                                 goto skip;
6017
6018                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6019                                               path->slots[level]);
6020                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6021                         if (ret < 0)
6022                                 goto skip;
6023
6024                         wc->stage = UPDATE_BACKREF;
6025                         wc->shared_level = level - 1;
6026                 }
6027         } else {
6028                 if (level == 1 &&
6029                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6030                         goto skip;
6031         }
6032
6033         if (!btrfs_buffer_uptodate(next, generation)) {
6034                 btrfs_tree_unlock(next);
6035                 free_extent_buffer(next);
6036                 next = NULL;
6037                 *lookup_info = 1;
6038         }
6039
6040         if (!next) {
6041                 if (reada && level == 1)
6042                         reada_walk_down(trans, root, wc, path);
6043                 next = read_tree_block(root, bytenr, blocksize, generation);
6044                 if (!next)
6045                         return -EIO;
6046                 btrfs_tree_lock(next);
6047                 btrfs_set_lock_blocking(next);
6048         }
6049
6050         level--;
6051         BUG_ON(level != btrfs_header_level(next));
6052         path->nodes[level] = next;
6053         path->slots[level] = 0;
6054         path->locks[level] = 1;
6055         wc->level = level;
6056         if (wc->level == 1)
6057                 wc->reada_slot = 0;
6058         return 0;
6059 skip:
6060         wc->refs[level - 1] = 0;
6061         wc->flags[level - 1] = 0;
6062         if (wc->stage == DROP_REFERENCE) {
6063                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6064                         parent = path->nodes[level]->start;
6065                 } else {
6066                         BUG_ON(root->root_key.objectid !=
6067                                btrfs_header_owner(path->nodes[level]));
6068                         parent = 0;
6069                 }
6070
6071                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6072                                         root->root_key.objectid, level - 1, 0);
6073                 BUG_ON(ret);
6074         }
6075         btrfs_tree_unlock(next);
6076         free_extent_buffer(next);
6077         *lookup_info = 1;
6078         return 1;
6079 }
6080
6081 /*
6082  * hepler to process tree block while walking up the tree.
6083  *
6084  * when wc->stage == DROP_REFERENCE, this function drops
6085  * reference count on the block.
6086  *
6087  * when wc->stage == UPDATE_BACKREF, this function changes
6088  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6089  * to UPDATE_BACKREF previously while processing the block.
6090  *
6091  * NOTE: return value 1 means we should stop walking up.
6092  */
6093 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6094                                  struct btrfs_root *root,
6095                                  struct btrfs_path *path,
6096                                  struct walk_control *wc)
6097 {
6098         int ret;
6099         int level = wc->level;
6100         struct extent_buffer *eb = path->nodes[level];
6101         u64 parent = 0;
6102
6103         if (wc->stage == UPDATE_BACKREF) {
6104                 BUG_ON(wc->shared_level < level);
6105                 if (level < wc->shared_level)
6106                         goto out;
6107
6108                 ret = find_next_key(path, level + 1, &wc->update_progress);
6109                 if (ret > 0)
6110                         wc->update_ref = 0;
6111
6112                 wc->stage = DROP_REFERENCE;
6113                 wc->shared_level = -1;
6114                 path->slots[level] = 0;
6115
6116                 /*
6117                  * check reference count again if the block isn't locked.
6118                  * we should start walking down the tree again if reference
6119                  * count is one.
6120                  */
6121                 if (!path->locks[level]) {
6122                         BUG_ON(level == 0);
6123                         btrfs_tree_lock(eb);
6124                         btrfs_set_lock_blocking(eb);
6125                         path->locks[level] = 1;
6126
6127                         ret = btrfs_lookup_extent_info(trans, root,
6128                                                        eb->start, eb->len,
6129                                                        &wc->refs[level],
6130                                                        &wc->flags[level]);
6131                         BUG_ON(ret);
6132                         BUG_ON(wc->refs[level] == 0);
6133                         if (wc->refs[level] == 1) {
6134                                 btrfs_tree_unlock(eb);
6135                                 path->locks[level] = 0;
6136                                 return 1;
6137                         }
6138                 }
6139         }
6140
6141         /* wc->stage == DROP_REFERENCE */
6142         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6143
6144         if (wc->refs[level] == 1) {
6145                 if (level == 0) {
6146                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6147                                 ret = btrfs_dec_ref(trans, root, eb, 1);
6148                         else
6149                                 ret = btrfs_dec_ref(trans, root, eb, 0);
6150                         BUG_ON(ret);
6151                 }
6152                 /* make block locked assertion in clean_tree_block happy */
6153                 if (!path->locks[level] &&
6154                     btrfs_header_generation(eb) == trans->transid) {
6155                         btrfs_tree_lock(eb);
6156                         btrfs_set_lock_blocking(eb);
6157                         path->locks[level] = 1;
6158                 }
6159                 clean_tree_block(trans, root, eb);
6160         }
6161
6162         if (eb == root->node) {
6163                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6164                         parent = eb->start;
6165                 else
6166                         BUG_ON(root->root_key.objectid !=
6167                                btrfs_header_owner(eb));
6168         } else {
6169                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6170                         parent = path->nodes[level + 1]->start;
6171                 else
6172                         BUG_ON(root->root_key.objectid !=
6173                                btrfs_header_owner(path->nodes[level + 1]));
6174         }
6175
6176         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
6177 out:
6178         wc->refs[level] = 0;
6179         wc->flags[level] = 0;
6180         return 0;
6181 }
6182
6183 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6184                                    struct btrfs_root *root,
6185                                    struct btrfs_path *path,
6186                                    struct walk_control *wc)
6187 {
6188         int level = wc->level;
6189         int lookup_info = 1;
6190         int ret;
6191
6192         while (level >= 0) {
6193                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6194                 if (ret > 0)
6195                         break;
6196
6197                 if (level == 0)
6198                         break;
6199
6200                 if (path->slots[level] >=
6201                     btrfs_header_nritems(path->nodes[level]))
6202                         break;
6203
6204                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6205                 if (ret > 0) {
6206                         path->slots[level]++;
6207                         continue;
6208                 } else if (ret < 0)
6209                         return ret;
6210                 level = wc->level;
6211         }
6212         return 0;
6213 }
6214
6215 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6216                                  struct btrfs_root *root,
6217                                  struct btrfs_path *path,
6218                                  struct walk_control *wc, int max_level)
6219 {
6220         int level = wc->level;
6221         int ret;
6222
6223         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6224         while (level < max_level && path->nodes[level]) {
6225                 wc->level = level;
6226                 if (path->slots[level] + 1 <
6227                     btrfs_header_nritems(path->nodes[level])) {
6228                         path->slots[level]++;
6229                         return 0;
6230                 } else {
6231                         ret = walk_up_proc(trans, root, path, wc);
6232                         if (ret > 0)
6233                                 return 0;
6234
6235                         if (path->locks[level]) {
6236                                 btrfs_tree_unlock(path->nodes[level]);
6237                                 path->locks[level] = 0;
6238                         }
6239                         free_extent_buffer(path->nodes[level]);
6240                         path->nodes[level] = NULL;
6241                         level++;
6242                 }
6243         }
6244         return 1;
6245 }
6246
6247 /*
6248  * drop a subvolume tree.
6249  *
6250  * this function traverses the tree freeing any blocks that only
6251  * referenced by the tree.
6252  *
6253  * when a shared tree block is found. this function decreases its
6254  * reference count by one. if update_ref is true, this function
6255  * also make sure backrefs for the shared block and all lower level
6256  * blocks are properly updated.
6257  */
6258 int btrfs_drop_snapshot(struct btrfs_root *root,
6259                         struct btrfs_block_rsv *block_rsv, int update_ref)
6260 {
6261         struct btrfs_path *path;
6262         struct btrfs_trans_handle *trans;
6263         struct btrfs_root *tree_root = root->fs_info->tree_root;
6264         struct btrfs_root_item *root_item = &root->root_item;
6265         struct walk_control *wc;
6266         struct btrfs_key key;
6267         int err = 0;
6268         int ret;
6269         int level;
6270
6271         path = btrfs_alloc_path();
6272         BUG_ON(!path);
6273
6274         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6275         BUG_ON(!wc);
6276
6277         trans = btrfs_start_transaction(tree_root, 0);
6278         BUG_ON(IS_ERR(trans));
6279
6280         if (block_rsv)
6281                 trans->block_rsv = block_rsv;
6282
6283         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6284                 level = btrfs_header_level(root->node);
6285                 path->nodes[level] = btrfs_lock_root_node(root);
6286                 btrfs_set_lock_blocking(path->nodes[level]);
6287                 path->slots[level] = 0;
6288                 path->locks[level] = 1;
6289                 memset(&wc->update_progress, 0,
6290                        sizeof(wc->update_progress));
6291         } else {
6292                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6293                 memcpy(&wc->update_progress, &key,
6294                        sizeof(wc->update_progress));
6295
6296                 level = root_item->drop_level;
6297                 BUG_ON(level == 0);
6298                 path->lowest_level = level;
6299                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6300                 path->lowest_level = 0;
6301                 if (ret < 0) {
6302                         err = ret;
6303                         goto out;
6304                 }
6305                 WARN_ON(ret > 0);
6306
6307                 /*
6308                  * unlock our path, this is safe because only this
6309                  * function is allowed to delete this snapshot
6310                  */
6311                 btrfs_unlock_up_safe(path, 0);
6312
6313                 level = btrfs_header_level(root->node);
6314                 while (1) {
6315                         btrfs_tree_lock(path->nodes[level]);
6316                         btrfs_set_lock_blocking(path->nodes[level]);
6317
6318                         ret = btrfs_lookup_extent_info(trans, root,
6319                                                 path->nodes[level]->start,
6320                                                 path->nodes[level]->len,
6321                                                 &wc->refs[level],
6322                                                 &wc->flags[level]);
6323                         BUG_ON(ret);
6324                         BUG_ON(wc->refs[level] == 0);
6325
6326                         if (level == root_item->drop_level)
6327                                 break;
6328
6329                         btrfs_tree_unlock(path->nodes[level]);
6330                         WARN_ON(wc->refs[level] != 1);
6331                         level--;
6332                 }
6333         }
6334
6335         wc->level = level;
6336         wc->shared_level = -1;
6337         wc->stage = DROP_REFERENCE;
6338         wc->update_ref = update_ref;
6339         wc->keep_locks = 0;
6340         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6341
6342         while (1) {
6343                 ret = walk_down_tree(trans, root, path, wc);
6344                 if (ret < 0) {
6345                         err = ret;
6346                         break;
6347                 }
6348
6349                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
6350                 if (ret < 0) {
6351                         err = ret;
6352                         break;
6353                 }
6354
6355                 if (ret > 0) {
6356                         BUG_ON(wc->stage != DROP_REFERENCE);
6357                         break;
6358                 }
6359
6360                 if (wc->stage == DROP_REFERENCE) {
6361                         level = wc->level;
6362                         btrfs_node_key(path->nodes[level],
6363                                        &root_item->drop_progress,
6364                                        path->slots[level]);
6365                         root_item->drop_level = level;
6366                 }
6367
6368                 BUG_ON(wc->level == 0);
6369                 if (btrfs_should_end_transaction(trans, tree_root)) {
6370                         ret = btrfs_update_root(trans, tree_root,
6371                                                 &root->root_key,
6372                                                 root_item);
6373                         BUG_ON(ret);
6374
6375                         btrfs_end_transaction_throttle(trans, tree_root);
6376                         trans = btrfs_start_transaction(tree_root, 0);
6377                         BUG_ON(IS_ERR(trans));
6378                         if (block_rsv)
6379                                 trans->block_rsv = block_rsv;
6380                 }
6381         }
6382         btrfs_release_path(path);
6383         BUG_ON(err);
6384
6385         ret = btrfs_del_root(trans, tree_root, &root->root_key);
6386         BUG_ON(ret);
6387
6388         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
6389                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
6390                                            NULL, NULL);
6391                 BUG_ON(ret < 0);
6392                 if (ret > 0) {
6393                         /* if we fail to delete the orphan item this time
6394                          * around, it'll get picked up the next time.
6395                          *
6396                          * The most common failure here is just -ENOENT.
6397                          */
6398                         btrfs_del_orphan_item(trans, tree_root,
6399                                               root->root_key.objectid);
6400                 }
6401         }
6402
6403         if (root->in_radix) {
6404                 btrfs_free_fs_root(tree_root->fs_info, root);
6405         } else {
6406                 free_extent_buffer(root->node);
6407                 free_extent_buffer(root->commit_root);
6408                 kfree(root);
6409         }
6410 out:
6411         btrfs_end_transaction_throttle(trans, tree_root);
6412         kfree(wc);
6413         btrfs_free_path(path);
6414         return err;
6415 }
6416
6417 /*
6418  * drop subtree rooted at tree block 'node'.
6419  *
6420  * NOTE: this function will unlock and release tree block 'node'
6421  */
6422 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6423                         struct btrfs_root *root,
6424                         struct extent_buffer *node,
6425                         struct extent_buffer *parent)
6426 {
6427         struct btrfs_path *path;
6428         struct walk_control *wc;
6429         int level;
6430         int parent_level;
6431         int ret = 0;
6432         int wret;
6433
6434         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6435
6436         path = btrfs_alloc_path();
6437         if (!path)
6438                 return -ENOMEM;
6439
6440         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6441         if (!wc) {
6442                 btrfs_free_path(path);
6443                 return -ENOMEM;
6444         }
6445
6446         btrfs_assert_tree_locked(parent);
6447         parent_level = btrfs_header_level(parent);
6448         extent_buffer_get(parent);
6449         path->nodes[parent_level] = parent;
6450         path->slots[parent_level] = btrfs_header_nritems(parent);
6451
6452         btrfs_assert_tree_locked(node);
6453         level = btrfs_header_level(node);
6454         path->nodes[level] = node;
6455         path->slots[level] = 0;
6456         path->locks[level] = 1;
6457
6458         wc->refs[parent_level] = 1;
6459         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6460         wc->level = level;
6461         wc->shared_level = -1;
6462         wc->stage = DROP_REFERENCE;
6463         wc->update_ref = 0;
6464         wc->keep_locks = 1;
6465         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6466
6467         while (1) {
6468                 wret = walk_down_tree(trans, root, path, wc);
6469                 if (wret < 0) {
6470                         ret = wret;
6471                         break;
6472                 }
6473
6474                 wret = walk_up_tree(trans, root, path, wc, parent_level);
6475                 if (wret < 0)
6476                         ret = wret;
6477                 if (wret != 0)
6478                         break;
6479         }
6480
6481         kfree(wc);
6482         btrfs_free_path(path);
6483         return ret;
6484 }
6485
6486 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
6487 {
6488         u64 num_devices;
6489         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
6490                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
6491
6492         /*
6493          * we add in the count of missing devices because we want
6494          * to make sure that any RAID levels on a degraded FS
6495          * continue to be honored.
6496          */
6497         num_devices = root->fs_info->fs_devices->rw_devices +
6498                 root->fs_info->fs_devices->missing_devices;
6499
6500         if (num_devices == 1) {
6501                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6502                 stripped = flags & ~stripped;
6503
6504                 /* turn raid0 into single device chunks */
6505                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
6506                         return stripped;
6507
6508                 /* turn mirroring into duplication */
6509                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
6510                              BTRFS_BLOCK_GROUP_RAID10))
6511                         return stripped | BTRFS_BLOCK_GROUP_DUP;
6512                 return flags;
6513         } else {
6514                 /* they already had raid on here, just return */
6515                 if (flags & stripped)
6516                         return flags;
6517
6518                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6519                 stripped = flags & ~stripped;
6520
6521                 /* switch duplicated blocks with raid1 */
6522                 if (flags & BTRFS_BLOCK_GROUP_DUP)
6523                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
6524
6525                 /* turn single device chunks into raid0 */
6526                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
6527         }
6528         return flags;
6529 }
6530
6531 static int set_block_group_ro(struct btrfs_block_group_cache *cache)
6532 {
6533         struct btrfs_space_info *sinfo = cache->space_info;
6534         u64 num_bytes;
6535         int ret = -ENOSPC;
6536
6537         if (cache->ro)
6538                 return 0;
6539
6540         spin_lock(&sinfo->lock);
6541         spin_lock(&cache->lock);
6542         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
6543                     cache->bytes_super - btrfs_block_group_used(&cache->item);
6544
6545         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
6546             sinfo->bytes_may_use + sinfo->bytes_readonly +
6547             cache->reserved_pinned + num_bytes <= sinfo->total_bytes) {
6548                 sinfo->bytes_readonly += num_bytes;
6549                 sinfo->bytes_reserved += cache->reserved_pinned;
6550                 cache->reserved_pinned = 0;
6551                 cache->ro = 1;
6552                 ret = 0;
6553         }
6554
6555         spin_unlock(&cache->lock);
6556         spin_unlock(&sinfo->lock);
6557         return ret;
6558 }
6559
6560 int btrfs_set_block_group_ro(struct btrfs_root *root,
6561                              struct btrfs_block_group_cache *cache)
6562
6563 {
6564         struct btrfs_trans_handle *trans;
6565         u64 alloc_flags;
6566         int ret;
6567
6568         BUG_ON(cache->ro);
6569
6570         trans = btrfs_join_transaction(root);
6571         BUG_ON(IS_ERR(trans));
6572
6573         alloc_flags = update_block_group_flags(root, cache->flags);
6574         if (alloc_flags != cache->flags)
6575                 do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6576                                CHUNK_ALLOC_FORCE);
6577
6578         ret = set_block_group_ro(cache);
6579         if (!ret)
6580                 goto out;
6581         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
6582         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6583                              CHUNK_ALLOC_FORCE);
6584         if (ret < 0)
6585                 goto out;
6586         ret = set_block_group_ro(cache);
6587 out:
6588         btrfs_end_transaction(trans, root);
6589         return ret;
6590 }
6591
6592 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
6593                             struct btrfs_root *root, u64 type)
6594 {
6595         u64 alloc_flags = get_alloc_profile(root, type);
6596         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6597                               CHUNK_ALLOC_FORCE);
6598 }
6599
6600 /*
6601  * helper to account the unused space of all the readonly block group in the
6602  * list. takes mirrors into account.
6603  */
6604 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
6605 {
6606         struct btrfs_block_group_cache *block_group;
6607         u64 free_bytes = 0;
6608         int factor;
6609
6610         list_for_each_entry(block_group, groups_list, list) {
6611                 spin_lock(&block_group->lock);
6612
6613                 if (!block_group->ro) {
6614                         spin_unlock(&block_group->lock);
6615                         continue;
6616                 }
6617
6618                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
6619                                           BTRFS_BLOCK_GROUP_RAID10 |
6620                                           BTRFS_BLOCK_GROUP_DUP))
6621                         factor = 2;
6622                 else
6623                         factor = 1;
6624
6625                 free_bytes += (block_group->key.offset -
6626                                btrfs_block_group_used(&block_group->item)) *
6627                                factor;
6628
6629                 spin_unlock(&block_group->lock);
6630         }
6631
6632         return free_bytes;
6633 }
6634
6635 /*
6636  * helper to account the unused space of all the readonly block group in the
6637  * space_info. takes mirrors into account.
6638  */
6639 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
6640 {
6641         int i;
6642         u64 free_bytes = 0;
6643
6644         spin_lock(&sinfo->lock);
6645
6646         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
6647                 if (!list_empty(&sinfo->block_groups[i]))
6648                         free_bytes += __btrfs_get_ro_block_group_free_space(
6649                                                 &sinfo->block_groups[i]);
6650
6651         spin_unlock(&sinfo->lock);
6652
6653         return free_bytes;
6654 }
6655
6656 int btrfs_set_block_group_rw(struct btrfs_root *root,
6657                               struct btrfs_block_group_cache *cache)
6658 {
6659         struct btrfs_space_info *sinfo = cache->space_info;
6660         u64 num_bytes;
6661
6662         BUG_ON(!cache->ro);
6663
6664         spin_lock(&sinfo->lock);
6665         spin_lock(&cache->lock);
6666         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
6667                     cache->bytes_super - btrfs_block_group_used(&cache->item);
6668         sinfo->bytes_readonly -= num_bytes;
6669         cache->ro = 0;
6670         spin_unlock(&cache->lock);
6671         spin_unlock(&sinfo->lock);
6672         return 0;
6673 }
6674
6675 /*
6676  * checks to see if its even possible to relocate this block group.
6677  *
6678  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
6679  * ok to go ahead and try.
6680  */
6681 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
6682 {
6683         struct btrfs_block_group_cache *block_group;
6684         struct btrfs_space_info *space_info;
6685         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6686         struct btrfs_device *device;
6687         int full = 0;
6688         int ret = 0;
6689
6690         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
6691
6692         /* odd, couldn't find the block group, leave it alone */
6693         if (!block_group)
6694                 return -1;
6695
6696         /* no bytes used, we're good */
6697         if (!btrfs_block_group_used(&block_group->item))
6698                 goto out;
6699
6700         space_info = block_group->space_info;
6701         spin_lock(&space_info->lock);
6702
6703         full = space_info->full;
6704
6705         /*
6706          * if this is the last block group we have in this space, we can't
6707          * relocate it unless we're able to allocate a new chunk below.
6708          *
6709          * Otherwise, we need to make sure we have room in the space to handle
6710          * all of the extents from this block group.  If we can, we're good
6711          */
6712         if ((space_info->total_bytes != block_group->key.offset) &&
6713            (space_info->bytes_used + space_info->bytes_reserved +
6714             space_info->bytes_pinned + space_info->bytes_readonly +
6715             btrfs_block_group_used(&block_group->item) <
6716             space_info->total_bytes)) {
6717                 spin_unlock(&space_info->lock);
6718                 goto out;
6719         }
6720         spin_unlock(&space_info->lock);
6721
6722         /*
6723          * ok we don't have enough space, but maybe we have free space on our
6724          * devices to allocate new chunks for relocation, so loop through our
6725          * alloc devices and guess if we have enough space.  However, if we
6726          * were marked as full, then we know there aren't enough chunks, and we
6727          * can just return.
6728          */
6729         ret = -1;
6730         if (full)
6731                 goto out;
6732
6733         mutex_lock(&root->fs_info->chunk_mutex);
6734         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
6735                 u64 min_free = btrfs_block_group_used(&block_group->item);
6736                 u64 dev_offset;
6737
6738                 /*
6739                  * check to make sure we can actually find a chunk with enough
6740                  * space to fit our block group in.
6741                  */
6742                 if (device->total_bytes > device->bytes_used + min_free) {
6743                         ret = find_free_dev_extent(NULL, device, min_free,
6744                                                    &dev_offset, NULL);
6745                         if (!ret)
6746                                 break;
6747                         ret = -1;
6748                 }
6749         }
6750         mutex_unlock(&root->fs_info->chunk_mutex);
6751 out:
6752         btrfs_put_block_group(block_group);
6753         return ret;
6754 }
6755
6756 static int find_first_block_group(struct btrfs_root *root,
6757                 struct btrfs_path *path, struct btrfs_key *key)
6758 {
6759         int ret = 0;
6760         struct btrfs_key found_key;
6761         struct extent_buffer *leaf;
6762         int slot;
6763
6764         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
6765         if (ret < 0)
6766                 goto out;
6767
6768         while (1) {
6769                 slot = path->slots[0];
6770                 leaf = path->nodes[0];
6771                 if (slot >= btrfs_header_nritems(leaf)) {
6772                         ret = btrfs_next_leaf(root, path);
6773                         if (ret == 0)
6774                                 continue;
6775                         if (ret < 0)
6776                                 goto out;
6777                         break;
6778                 }
6779                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6780
6781                 if (found_key.objectid >= key->objectid &&
6782                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
6783                         ret = 0;
6784                         goto out;
6785                 }
6786                 path->slots[0]++;
6787         }
6788 out:
6789         return ret;
6790 }
6791
6792 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
6793 {
6794         struct btrfs_block_group_cache *block_group;
6795         u64 last = 0;
6796
6797         while (1) {
6798                 struct inode *inode;
6799
6800                 block_group = btrfs_lookup_first_block_group(info, last);
6801                 while (block_group) {
6802                         spin_lock(&block_group->lock);
6803                         if (block_group->iref)
6804                                 break;
6805                         spin_unlock(&block_group->lock);
6806                         block_group = next_block_group(info->tree_root,
6807                                                        block_group);
6808                 }
6809                 if (!block_group) {
6810                         if (last == 0)
6811                                 break;
6812                         last = 0;
6813                         continue;
6814                 }
6815
6816                 inode = block_group->inode;
6817                 block_group->iref = 0;
6818                 block_group->inode = NULL;
6819                 spin_unlock(&block_group->lock);
6820                 iput(inode);
6821                 last = block_group->key.objectid + block_group->key.offset;
6822                 btrfs_put_block_group(block_group);
6823         }
6824 }
6825
6826 int btrfs_free_block_groups(struct btrfs_fs_info *info)
6827 {
6828         struct btrfs_block_group_cache *block_group;
6829         struct btrfs_space_info *space_info;
6830         struct btrfs_caching_control *caching_ctl;
6831         struct rb_node *n;
6832
6833         down_write(&info->extent_commit_sem);
6834         while (!list_empty(&info->caching_block_groups)) {
6835                 caching_ctl = list_entry(info->caching_block_groups.next,
6836                                          struct btrfs_caching_control, list);
6837                 list_del(&caching_ctl->list);
6838                 put_caching_control(caching_ctl);
6839         }
6840         up_write(&info->extent_commit_sem);
6841
6842         spin_lock(&info->block_group_cache_lock);
6843         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
6844                 block_group = rb_entry(n, struct btrfs_block_group_cache,
6845                                        cache_node);
6846                 rb_erase(&block_group->cache_node,
6847                          &info->block_group_cache_tree);
6848                 spin_unlock(&info->block_group_cache_lock);
6849
6850                 down_write(&block_group->space_info->groups_sem);
6851                 list_del(&block_group->list);
6852                 up_write(&block_group->space_info->groups_sem);
6853
6854                 if (block_group->cached == BTRFS_CACHE_STARTED)
6855                         wait_block_group_cache_done(block_group);
6856
6857                 /*
6858                  * We haven't cached this block group, which means we could
6859                  * possibly have excluded extents on this block group.
6860                  */
6861                 if (block_group->cached == BTRFS_CACHE_NO)
6862                         free_excluded_extents(info->extent_root, block_group);
6863
6864                 btrfs_remove_free_space_cache(block_group);
6865                 btrfs_put_block_group(block_group);
6866
6867                 spin_lock(&info->block_group_cache_lock);
6868         }
6869         spin_unlock(&info->block_group_cache_lock);
6870
6871         /* now that all the block groups are freed, go through and
6872          * free all the space_info structs.  This is only called during
6873          * the final stages of unmount, and so we know nobody is
6874          * using them.  We call synchronize_rcu() once before we start,
6875          * just to be on the safe side.
6876          */
6877         synchronize_rcu();
6878
6879         release_global_block_rsv(info);
6880
6881         while(!list_empty(&info->space_info)) {
6882                 space_info = list_entry(info->space_info.next,
6883                                         struct btrfs_space_info,
6884                                         list);
6885                 if (space_info->bytes_pinned > 0 ||
6886                     space_info->bytes_reserved > 0) {
6887                         WARN_ON(1);
6888                         dump_space_info(space_info, 0, 0);
6889                 }
6890                 list_del(&space_info->list);
6891                 kfree(space_info);
6892         }
6893         return 0;
6894 }
6895
6896 static void __link_block_group(struct btrfs_space_info *space_info,
6897                                struct btrfs_block_group_cache *cache)
6898 {
6899         int index = get_block_group_index(cache);
6900
6901         down_write(&space_info->groups_sem);
6902         list_add_tail(&cache->list, &space_info->block_groups[index]);
6903         up_write(&space_info->groups_sem);
6904 }
6905
6906 int btrfs_read_block_groups(struct btrfs_root *root)
6907 {
6908         struct btrfs_path *path;
6909         int ret;
6910         struct btrfs_block_group_cache *cache;
6911         struct btrfs_fs_info *info = root->fs_info;
6912         struct btrfs_space_info *space_info;
6913         struct btrfs_key key;
6914         struct btrfs_key found_key;
6915         struct extent_buffer *leaf;
6916         int need_clear = 0;
6917         u64 cache_gen;
6918
6919         root = info->extent_root;
6920         key.objectid = 0;
6921         key.offset = 0;
6922         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
6923         path = btrfs_alloc_path();
6924         if (!path)
6925                 return -ENOMEM;
6926         path->reada = 1;
6927
6928         cache_gen = btrfs_super_cache_generation(&root->fs_info->super_copy);
6929         if (cache_gen != 0 &&
6930             btrfs_super_generation(&root->fs_info->super_copy) != cache_gen)
6931                 need_clear = 1;
6932         if (btrfs_test_opt(root, CLEAR_CACHE))
6933                 need_clear = 1;
6934         if (!btrfs_test_opt(root, SPACE_CACHE) && cache_gen)
6935                 printk(KERN_INFO "btrfs: disk space caching is enabled\n");
6936
6937         while (1) {
6938                 ret = find_first_block_group(root, path, &key);
6939                 if (ret > 0)
6940                         break;
6941                 if (ret != 0)
6942                         goto error;
6943                 leaf = path->nodes[0];
6944                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6945                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
6946                 if (!cache) {
6947                         ret = -ENOMEM;
6948                         goto error;
6949                 }
6950                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
6951                                                 GFP_NOFS);
6952                 if (!cache->free_space_ctl) {
6953                         kfree(cache);
6954                         ret = -ENOMEM;
6955                         goto error;
6956                 }
6957
6958                 atomic_set(&cache->count, 1);
6959                 spin_lock_init(&cache->lock);
6960                 cache->fs_info = info;
6961                 INIT_LIST_HEAD(&cache->list);
6962                 INIT_LIST_HEAD(&cache->cluster_list);
6963
6964                 if (need_clear)
6965                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6966
6967                 read_extent_buffer(leaf, &cache->item,
6968                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
6969                                    sizeof(cache->item));
6970                 memcpy(&cache->key, &found_key, sizeof(found_key));
6971
6972                 key.objectid = found_key.objectid + found_key.offset;
6973                 btrfs_release_path(path);
6974                 cache->flags = btrfs_block_group_flags(&cache->item);
6975                 cache->sectorsize = root->sectorsize;
6976
6977                 btrfs_init_free_space_ctl(cache);
6978
6979                 /*
6980                  * We need to exclude the super stripes now so that the space
6981                  * info has super bytes accounted for, otherwise we'll think
6982                  * we have more space than we actually do.
6983                  */
6984                 exclude_super_stripes(root, cache);
6985
6986                 /*
6987                  * check for two cases, either we are full, and therefore
6988                  * don't need to bother with the caching work since we won't
6989                  * find any space, or we are empty, and we can just add all
6990                  * the space in and be done with it.  This saves us _alot_ of
6991                  * time, particularly in the full case.
6992                  */
6993                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
6994                         cache->last_byte_to_unpin = (u64)-1;
6995                         cache->cached = BTRFS_CACHE_FINISHED;
6996                         free_excluded_extents(root, cache);
6997                 } else if (btrfs_block_group_used(&cache->item) == 0) {
6998                         cache->last_byte_to_unpin = (u64)-1;
6999                         cache->cached = BTRFS_CACHE_FINISHED;
7000                         add_new_free_space(cache, root->fs_info,
7001                                            found_key.objectid,
7002                                            found_key.objectid +
7003                                            found_key.offset);
7004                         free_excluded_extents(root, cache);
7005                 }
7006
7007                 ret = update_space_info(info, cache->flags, found_key.offset,
7008                                         btrfs_block_group_used(&cache->item),
7009                                         &space_info);
7010                 BUG_ON(ret);
7011                 cache->space_info = space_info;
7012                 spin_lock(&cache->space_info->lock);
7013                 cache->space_info->bytes_readonly += cache->bytes_super;
7014                 spin_unlock(&cache->space_info->lock);
7015
7016                 __link_block_group(space_info, cache);
7017
7018                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7019                 BUG_ON(ret);
7020
7021                 set_avail_alloc_bits(root->fs_info, cache->flags);
7022                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7023                         set_block_group_ro(cache);
7024         }
7025
7026         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7027                 if (!(get_alloc_profile(root, space_info->flags) &
7028                       (BTRFS_BLOCK_GROUP_RAID10 |
7029                        BTRFS_BLOCK_GROUP_RAID1 |
7030                        BTRFS_BLOCK_GROUP_DUP)))
7031                         continue;
7032                 /*
7033                  * avoid allocating from un-mirrored block group if there are
7034                  * mirrored block groups.
7035                  */
7036                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7037                         set_block_group_ro(cache);
7038                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7039                         set_block_group_ro(cache);
7040         }
7041
7042         init_global_block_rsv(info);
7043         ret = 0;
7044 error:
7045         btrfs_free_path(path);
7046         return ret;
7047 }
7048
7049 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7050                            struct btrfs_root *root, u64 bytes_used,
7051                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7052                            u64 size)
7053 {
7054         int ret;
7055         struct btrfs_root *extent_root;
7056         struct btrfs_block_group_cache *cache;
7057
7058         extent_root = root->fs_info->extent_root;
7059
7060         root->fs_info->last_trans_log_full_commit = trans->transid;
7061
7062         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7063         if (!cache)
7064                 return -ENOMEM;
7065         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7066                                         GFP_NOFS);
7067         if (!cache->free_space_ctl) {
7068                 kfree(cache);
7069                 return -ENOMEM;
7070         }
7071
7072         cache->key.objectid = chunk_offset;
7073         cache->key.offset = size;
7074         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7075         cache->sectorsize = root->sectorsize;
7076         cache->fs_info = root->fs_info;
7077
7078         atomic_set(&cache->count, 1);
7079         spin_lock_init(&cache->lock);
7080         INIT_LIST_HEAD(&cache->list);
7081         INIT_LIST_HEAD(&cache->cluster_list);
7082
7083         btrfs_init_free_space_ctl(cache);
7084
7085         btrfs_set_block_group_used(&cache->item, bytes_used);
7086         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7087         cache->flags = type;
7088         btrfs_set_block_group_flags(&cache->item, type);
7089
7090         cache->last_byte_to_unpin = (u64)-1;
7091         cache->cached = BTRFS_CACHE_FINISHED;
7092         exclude_super_stripes(root, cache);
7093
7094         add_new_free_space(cache, root->fs_info, chunk_offset,
7095                            chunk_offset + size);
7096
7097         free_excluded_extents(root, cache);
7098
7099         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7100                                 &cache->space_info);
7101         BUG_ON(ret);
7102
7103         spin_lock(&cache->space_info->lock);
7104         cache->space_info->bytes_readonly += cache->bytes_super;
7105         spin_unlock(&cache->space_info->lock);
7106
7107         __link_block_group(cache->space_info, cache);
7108
7109         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7110         BUG_ON(ret);
7111
7112         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7113                                 sizeof(cache->item));
7114         BUG_ON(ret);
7115
7116         set_avail_alloc_bits(extent_root->fs_info, type);
7117
7118         return 0;
7119 }
7120
7121 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7122                              struct btrfs_root *root, u64 group_start)
7123 {
7124         struct btrfs_path *path;
7125         struct btrfs_block_group_cache *block_group;
7126         struct btrfs_free_cluster *cluster;
7127         struct btrfs_root *tree_root = root->fs_info->tree_root;
7128         struct btrfs_key key;
7129         struct inode *inode;
7130         int ret;
7131         int factor;
7132
7133         root = root->fs_info->extent_root;
7134
7135         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7136         BUG_ON(!block_group);
7137         BUG_ON(!block_group->ro);
7138
7139         /*
7140          * Free the reserved super bytes from this block group before
7141          * remove it.
7142          */
7143         free_excluded_extents(root, block_group);
7144
7145         memcpy(&key, &block_group->key, sizeof(key));
7146         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7147                                   BTRFS_BLOCK_GROUP_RAID1 |
7148                                   BTRFS_BLOCK_GROUP_RAID10))
7149                 factor = 2;
7150         else
7151                 factor = 1;
7152
7153         /* make sure this block group isn't part of an allocation cluster */
7154         cluster = &root->fs_info->data_alloc_cluster;
7155         spin_lock(&cluster->refill_lock);
7156         btrfs_return_cluster_to_free_space(block_group, cluster);
7157         spin_unlock(&cluster->refill_lock);
7158
7159         /*
7160          * make sure this block group isn't part of a metadata
7161          * allocation cluster
7162          */
7163         cluster = &root->fs_info->meta_alloc_cluster;
7164         spin_lock(&cluster->refill_lock);
7165         btrfs_return_cluster_to_free_space(block_group, cluster);
7166         spin_unlock(&cluster->refill_lock);
7167
7168         path = btrfs_alloc_path();
7169         BUG_ON(!path);
7170
7171         inode = lookup_free_space_inode(root, block_group, path);
7172         if (!IS_ERR(inode)) {
7173                 btrfs_orphan_add(trans, inode);
7174                 clear_nlink(inode);
7175                 /* One for the block groups ref */
7176                 spin_lock(&block_group->lock);
7177                 if (block_group->iref) {
7178                         block_group->iref = 0;
7179                         block_group->inode = NULL;
7180                         spin_unlock(&block_group->lock);
7181                         iput(inode);
7182                 } else {
7183                         spin_unlock(&block_group->lock);
7184                 }
7185                 /* One for our lookup ref */
7186                 iput(inode);
7187         }
7188
7189         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7190         key.offset = block_group->key.objectid;
7191         key.type = 0;
7192
7193         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7194         if (ret < 0)
7195                 goto out;
7196         if (ret > 0)
7197                 btrfs_release_path(path);
7198         if (ret == 0) {
7199                 ret = btrfs_del_item(trans, tree_root, path);
7200                 if (ret)
7201                         goto out;
7202                 btrfs_release_path(path);
7203         }
7204
7205         spin_lock(&root->fs_info->block_group_cache_lock);
7206         rb_erase(&block_group->cache_node,
7207                  &root->fs_info->block_group_cache_tree);
7208         spin_unlock(&root->fs_info->block_group_cache_lock);
7209
7210         down_write(&block_group->space_info->groups_sem);
7211         /*
7212          * we must use list_del_init so people can check to see if they
7213          * are still on the list after taking the semaphore
7214          */
7215         list_del_init(&block_group->list);
7216         up_write(&block_group->space_info->groups_sem);
7217
7218         if (block_group->cached == BTRFS_CACHE_STARTED)
7219                 wait_block_group_cache_done(block_group);
7220
7221         btrfs_remove_free_space_cache(block_group);
7222
7223         spin_lock(&block_group->space_info->lock);
7224         block_group->space_info->total_bytes -= block_group->key.offset;
7225         block_group->space_info->bytes_readonly -= block_group->key.offset;
7226         block_group->space_info->disk_total -= block_group->key.offset * factor;
7227         spin_unlock(&block_group->space_info->lock);
7228
7229         memcpy(&key, &block_group->key, sizeof(key));
7230
7231         btrfs_clear_space_info_full(root->fs_info);
7232
7233         btrfs_put_block_group(block_group);
7234         btrfs_put_block_group(block_group);
7235
7236         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
7237         if (ret > 0)
7238                 ret = -EIO;
7239         if (ret < 0)
7240                 goto out;
7241
7242         ret = btrfs_del_item(trans, root, path);
7243 out:
7244         btrfs_free_path(path);
7245         return ret;
7246 }
7247
7248 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
7249 {
7250         struct btrfs_space_info *space_info;
7251         struct btrfs_super_block *disk_super;
7252         u64 features;
7253         u64 flags;
7254         int mixed = 0;
7255         int ret;
7256
7257         disk_super = &fs_info->super_copy;
7258         if (!btrfs_super_root(disk_super))
7259                 return 1;
7260
7261         features = btrfs_super_incompat_flags(disk_super);
7262         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
7263                 mixed = 1;
7264
7265         flags = BTRFS_BLOCK_GROUP_SYSTEM;
7266         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7267         if (ret)
7268                 goto out;
7269
7270         if (mixed) {
7271                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
7272                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7273         } else {
7274                 flags = BTRFS_BLOCK_GROUP_METADATA;
7275                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7276                 if (ret)
7277                         goto out;
7278
7279                 flags = BTRFS_BLOCK_GROUP_DATA;
7280                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7281         }
7282 out:
7283         return ret;
7284 }
7285
7286 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
7287 {
7288         return unpin_extent_range(root, start, end);
7289 }
7290
7291 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
7292                                u64 num_bytes, u64 *actual_bytes)
7293 {
7294         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
7295 }
7296
7297 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
7298 {
7299         struct btrfs_fs_info *fs_info = root->fs_info;
7300         struct btrfs_block_group_cache *cache = NULL;
7301         u64 group_trimmed;
7302         u64 start;
7303         u64 end;
7304         u64 trimmed = 0;
7305         int ret = 0;
7306
7307         cache = btrfs_lookup_block_group(fs_info, range->start);
7308
7309         while (cache) {
7310                 if (cache->key.objectid >= (range->start + range->len)) {
7311                         btrfs_put_block_group(cache);
7312                         break;
7313                 }
7314
7315                 start = max(range->start, cache->key.objectid);
7316                 end = min(range->start + range->len,
7317                                 cache->key.objectid + cache->key.offset);
7318
7319                 if (end - start >= range->minlen) {
7320                         if (!block_group_cache_done(cache)) {
7321                                 ret = cache_block_group(cache, NULL, root, 0);
7322                                 if (!ret)
7323                                         wait_block_group_cache_done(cache);
7324                         }
7325                         ret = btrfs_trim_block_group(cache,
7326                                                      &group_trimmed,
7327                                                      start,
7328                                                      end,
7329                                                      range->minlen);
7330
7331                         trimmed += group_trimmed;
7332                         if (ret) {
7333                                 btrfs_put_block_group(cache);
7334                                 break;
7335                         }
7336                 }
7337
7338                 cache = next_block_group(fs_info->tree_root, cache);
7339         }
7340
7341         range->len = trimmed;
7342         return ret;
7343 }