fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include "compat.h"
  28 #include "hash.h"
  29 #include "ctree.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "transaction.h"
  33 #include "volumes.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36
  37 /*
  38  * control flags for do_chunk_alloc's force field
  39  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  40  * if we really need 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  * CHUNK_ALLOC_FORCE means it must try to allocate one
  49  *
  50  */
  51 enum {
  52         CHUNK_ALLOC_NO_FORCE = 0,
  53         CHUNK_ALLOC_LIMITED = 1,
  54         CHUNK_ALLOC_FORCE = 2,
  55 };
  56
  57 /*
  58  * Control how reservations are dealt with.
  59  *
  60  * RESERVE_FREE - freeing a reservation.
  61  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  62  *   ENOSPC accounting
  63  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  64  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  65  */
  66 enum {
  67         RESERVE_FREE = 0,
  68         RESERVE_ALLOC = 1,
  69         RESERVE_ALLOC_NO_ACCOUNT = 2,
  70 };
  71
  72 static int update_block_group(struct btrfs_trans_handle *trans,
  73                               struct btrfs_root *root,
  74                               u64 bytenr, u64 num_bytes, int alloc);
  75 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  76                                 struct btrfs_root *root,
  77                                 u64 bytenr, u64 num_bytes, u64 parent,
  78                                 u64 root_objectid, u64 owner_objectid,
  79                                 u64 owner_offset, int refs_to_drop,
  80                                 struct btrfs_delayed_extent_op *extra_op);
  81 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  82                                     struct extent_buffer *leaf,
  83                                     struct btrfs_extent_item *ei);
  84 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  85                                       struct btrfs_root *root,
  86                                       u64 parent, u64 root_objectid,
  87                                       u64 flags, u64 owner, u64 offset,
  88                                       struct btrfs_key *ins, int ref_mod);
  89 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  90                                      struct btrfs_root *root,
  91                                      u64 parent, u64 root_objectid,
  92                                      u64 flags, struct btrfs_disk_key *key,
  93                                      int level, struct btrfs_key *ins);
  94 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  95                           struct btrfs_root *extent_root, u64 alloc_bytes,
  96                           u64 flags, int force);
  97 static int find_next_key(struct btrfs_path *path, int level,
  98                          struct btrfs_key *key);
  99 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 100                             int dump_block_groups);
 101 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 102                                        u64 num_bytes, int reserve);
 103
 104 static noinline int
 105 block_group_cache_done(struct btrfs_block_group_cache *cache)
 106 {
 107         smp_mb();
 108         return cache->cached == BTRFS_CACHE_FINISHED;
 109 }
 110
 111 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 112 {
 113         return (cache->flags & bits) == bits;
 114 }
 115
 116 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 117 {
 118         atomic_inc(&cache->count);
 119 }
 120
 121 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 122 {
 123         if (atomic_dec_and_test(&cache->count)) {
 124                 WARN_ON(cache->pinned > 0);
 125                 WARN_ON(cache->reserved > 0);
 126                 kfree(cache->free_space_ctl);
 127                 kfree(cache);
 128         }
 129 }
 130
 131 /*
 132  * this adds the block group to the fs_info rb tree for the block group
 133  * cache
 134  */
 135 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 136                                 struct btrfs_block_group_cache *block_group)
 137 {
 138         struct rb_node **p;
 139         struct rb_node *parent = NULL;
 140         struct btrfs_block_group_cache *cache;
 141
 142         spin_lock(&info->block_group_cache_lock);
 143         p = &info->block_group_cache_tree.rb_node;
 144
 145         while (*p) {
 146                 parent = *p;
 147                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 148                                  cache_node);
 149                 if (block_group->key.objectid < cache->key.objectid) {
 150                         p = &(*p)->rb_left;
 151                 } else if (block_group->key.objectid > cache->key.objectid) {
 152                         p = &(*p)->rb_right;
 153                 } else {
 154                         spin_unlock(&info->block_group_cache_lock);
 155                         return -EEXIST;
 156                 }
 157         }
 158
 159         rb_link_node(&block_group->cache_node, parent, p);
 160         rb_insert_color(&block_group->cache_node,
 161                         &info->block_group_cache_tree);
 162         spin_unlock(&info->block_group_cache_lock);
 163
 164         return 0;
 165 }
 166
 167 /*
 168  * This will return the block group at or after bytenr if contains is 0, else
 169  * it will return the block group that contains the bytenr
 170  */
 171 static struct btrfs_block_group_cache *
 172 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 173                               int contains)
 174 {
 175         struct btrfs_block_group_cache *cache, *ret = NULL;
 176         struct rb_node *n;
 177         u64 end, start;
 178
 179         spin_lock(&info->block_group_cache_lock);
 180         n = info->block_group_cache_tree.rb_node;
 181
 182         while (n) {
 183                 cache = rb_entry(n, struct btrfs_block_group_cache,
 184                                  cache_node);
 185                 end = cache->key.objectid + cache->key.offset - 1;
 186                 start = cache->key.objectid;
 187
 188                 if (bytenr < start) {
 189                         if (!contains && (!ret || start < ret->key.objectid))
 190                                 ret = cache;
 191                         n = n->rb_left;
 192                 } else if (bytenr > start) {
 193                         if (contains && bytenr <= end) {
 194                                 ret = cache;
 195                                 break;
 196                         }
 197                         n = n->rb_right;
 198                 } else {
 199                         ret = cache;
 200                         break;
 201                 }
 202         }
 203         if (ret)
 204                 btrfs_get_block_group(ret);
 205         spin_unlock(&info->block_group_cache_lock);
 206
 207         return ret;
 208 }
 209
 210 static int add_excluded_extent(struct btrfs_root *root,
 211                                u64 start, u64 num_bytes)
 212 {
 213         u64 end = start + num_bytes - 1;
 214         set_extent_bits(&root->fs_info->freed_extents[0],
 215                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 216         set_extent_bits(&root->fs_info->freed_extents[1],
 217                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 218         return 0;
 219 }
 220
 221 static void free_excluded_extents(struct btrfs_root *root,
 222                                   struct btrfs_block_group_cache *cache)
 223 {
 224         u64 start, end;
 225
 226         start = cache->key.objectid;
 227         end = start + cache->key.offset - 1;
 228
 229         clear_extent_bits(&root->fs_info->freed_extents[0],
 230                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 231         clear_extent_bits(&root->fs_info->freed_extents[1],
 232                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 233 }
 234
 235 static int exclude_super_stripes(struct btrfs_root *root,
 236                                  struct btrfs_block_group_cache *cache)
 237 {
 238         u64 bytenr;
 239         u64 *logical;
 240         int stripe_len;
 241         int i, nr, ret;
 242
 243         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 244                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 245                 cache->bytes_super += stripe_len;
 246                 ret = add_excluded_extent(root, cache->key.objectid,
 247                                           stripe_len);
 248                 BUG_ON(ret);
 249         }
 250
 251         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 252                 bytenr = btrfs_sb_offset(i);
 253                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 254                                        cache->key.objectid, bytenr,
 255                                        0, &logical, &nr, &stripe_len);
 256                 BUG_ON(ret);
 257
 258                 while (nr--) {
 259                         cache->bytes_super += stripe_len;
 260                         ret = add_excluded_extent(root, logical[nr],
 261                                                   stripe_len);
 262                         BUG_ON(ret);
 263                 }
 264
 265                 kfree(logical);
 266         }
 267         return 0;
 268 }
 269
 270 static struct btrfs_caching_control *
 271 get_caching_control(struct btrfs_block_group_cache *cache)
 272 {
 273         struct btrfs_caching_control *ctl;
 274
 275         spin_lock(&cache->lock);
 276         if (cache->cached != BTRFS_CACHE_STARTED) {
 277                 spin_unlock(&cache->lock);
 278                 return NULL;
 279         }
 280
 281         /* We're loading it the fast way, so we don't have a caching_ctl. */
 282         if (!cache->caching_ctl) {
 283                 spin_unlock(&cache->lock);
 284                 return NULL;
 285         }
 286
 287         ctl = cache->caching_ctl;
 288         atomic_inc(&ctl->count);
 289         spin_unlock(&cache->lock);
 290         return ctl;
 291 }
 292
 293 static void put_caching_control(struct btrfs_caching_control *ctl)
 294 {
 295         if (atomic_dec_and_test(&ctl->count))
 296                 kfree(ctl);
 297 }
 298
 299 /*
 300  * this is only called by cache_block_group, since we could have freed extents
 301  * we need to check the pinned_extents for any extents that can't be used yet
 302  * since their free space will be released as soon as the transaction commits.
 303  */
 304 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 305                               struct btrfs_fs_info *info, u64 start, u64 end)
 306 {
 307         u64 extent_start, extent_end, size, total_added = 0;
 308         int ret;
 309
 310         while (start < end) {
 311                 ret = find_first_extent_bit(info->pinned_extents, start,
 312                                             &extent_start, &extent_end,
 313                                             EXTENT_DIRTY | EXTENT_UPTODATE);
 314                 if (ret)
 315                         break;
 316
 317                 if (extent_start <= start) {
 318                         start = extent_end + 1;
 319                 } else if (extent_start > start && extent_start < end) {
 320                         size = extent_start - start;
 321                         total_added += size;
 322                         ret = btrfs_add_free_space(block_group, start,
 323                                                    size);
 324                         BUG_ON(ret);
 325                         start = extent_end + 1;
 326                 } else {
 327                         break;
 328                 }
 329         }
 330
 331         if (start < end) {
 332                 size = end - start;
 333                 total_added += size;
 334                 ret = btrfs_add_free_space(block_group, start, size);
 335                 BUG_ON(ret);
 336         }
 337
 338         return total_added;
 339 }
 340
 341 static noinline void caching_thread(struct btrfs_work *work)
 342 {
 343         struct btrfs_block_group_cache *block_group;
 344         struct btrfs_fs_info *fs_info;
 345         struct btrfs_caching_control *caching_ctl;
 346         struct btrfs_root *extent_root;
 347         struct btrfs_path *path;
 348         struct extent_buffer *leaf;
 349         struct btrfs_key key;
 350         u64 total_found = 0;
 351         u64 last = 0;
 352         u32 nritems;
 353         int ret = 0;
 354
 355         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 356         block_group = caching_ctl->block_group;
 357         fs_info = block_group->fs_info;
 358         extent_root = fs_info->extent_root;
 359
 360         path = btrfs_alloc_path();
 361         if (!path)
 362                 goto out;
 363
 364         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 365
 366         /*
 367          * We don't want to deadlock with somebody trying to allocate a new
 368          * extent for the extent root while also trying to search the extent
 369          * root to add free space.  So we skip locking and search the commit
 370          * root, since its read-only
 371          */
 372         path->skip_locking = 1;
 373         path->search_commit_root = 1;
 374         path->reada = 1;
 375
 376         key.objectid = last;
 377         key.offset = 0;
 378         key.type = BTRFS_EXTENT_ITEM_KEY;
 379 again:
 380         mutex_lock(&caching_ctl->mutex);
 381         /* need to make sure the commit_root doesn't disappear */
 382         down_read(&fs_info->extent_commit_sem);
 383
 384         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 385         if (ret < 0)
 386                 goto err;
 387
 388         leaf = path->nodes[0];
 389         nritems = btrfs_header_nritems(leaf);
 390
 391         while (1) {
 392                 if (btrfs_fs_closing(fs_info) > 1) {
 393                         last = (u64)-1;
 394                         break;
 395                 }
 396
 397                 if (path->slots[0] < nritems) {
 398                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 399                 } else {
 400                         ret = find_next_key(path, 0, &key);
 401                         if (ret)
 402                                 break;
 403
 404                         if (need_resched() ||
 405                             btrfs_next_leaf(extent_root, path)) {
 406                                 caching_ctl->progress = last;
 407                                 btrfs_release_path(path);
 408                                 up_read(&fs_info->extent_commit_sem);
 409                                 mutex_unlock(&caching_ctl->mutex);
 410                                 cond_resched();
 411                                 goto again;
 412                         }
 413                         leaf = path->nodes[0];
 414                         nritems = btrfs_header_nritems(leaf);
 415                         continue;
 416                 }
 417
 418                 if (key.objectid < block_group->key.objectid) {
 419                         path->slots[0]++;
 420                         continue;
 421                 }
 422
 423                 if (key.objectid >= block_group->key.objectid +
 424                     block_group->key.offset)
 425                         break;
 426
 427                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 428                         total_found += add_new_free_space(block_group,
 429                                                           fs_info, last,
 430                                                           key.objectid);
 431                         last = key.objectid + key.offset;
 432
 433                         if (total_found > (1024 * 1024 * 2)) {
 434                                 total_found = 0;
 435                                 wake_up(&caching_ctl->wait);
 436                         }
 437                 }
 438                 path->slots[0]++;
 439         }
 440         ret = 0;
 441
 442         total_found += add_new_free_space(block_group, fs_info, last,
 443                                           block_group->key.objectid +
 444                                           block_group->key.offset);
 445         caching_ctl->progress = (u64)-1;
 446
 447         spin_lock(&block_group->lock);
 448         block_group->caching_ctl = NULL;
 449         block_group->cached = BTRFS_CACHE_FINISHED;
 450         spin_unlock(&block_group->lock);
 451
 452 err:
 453         btrfs_free_path(path);
 454         up_read(&fs_info->extent_commit_sem);
 455
 456         free_excluded_extents(extent_root, block_group);
 457
 458         mutex_unlock(&caching_ctl->mutex);
 459 out:
 460         wake_up(&caching_ctl->wait);
 461
 462         put_caching_control(caching_ctl);
 463         btrfs_put_block_group(block_group);
 464 }
 465
 466 static int cache_block_group(struct btrfs_block_group_cache *cache,
 467                              struct btrfs_trans_handle *trans,
 468                              struct btrfs_root *root,
 469                              int load_cache_only)
 470 {
 471         DEFINE_WAIT(wait);
 472         struct btrfs_fs_info *fs_info = cache->fs_info;
 473         struct btrfs_caching_control *caching_ctl;
 474         int ret = 0;
 475
 476         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 477         BUG_ON(!caching_ctl);
 478
 479         INIT_LIST_HEAD(&caching_ctl->list);
 480         mutex_init(&caching_ctl->mutex);
 481         init_waitqueue_head(&caching_ctl->wait);
 482         caching_ctl->block_group = cache;
 483         caching_ctl->progress = cache->key.objectid;
 484         atomic_set(&caching_ctl->count, 1);
 485         caching_ctl->work.func = caching_thread;
 486
 487         spin_lock(&cache->lock);
 488         /*
 489          * This should be a rare occasion, but this could happen I think in the
 490          * case where one thread starts to load the space cache info, and then
 491          * some other thread starts a transaction commit which tries to do an
 492          * allocation while the other thread is still loading the space cache
 493          * info.  The previous loop should have kept us from choosing this block
 494          * group, but if we've moved to the state where we will wait on caching
 495          * block groups we need to first check if we're doing a fast load here,
 496          * so we can wait for it to finish, otherwise we could end up allocating
 497          * from a block group who's cache gets evicted for one reason or
 498          * another.
 499          */
 500         while (cache->cached == BTRFS_CACHE_FAST) {
 501                 struct btrfs_caching_control *ctl;
 502
 503                 ctl = cache->caching_ctl;
 504                 atomic_inc(&ctl->count);
 505                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 506                 spin_unlock(&cache->lock);
 507
 508                 schedule();
 509
 510                 finish_wait(&ctl->wait, &wait);
 511                 put_caching_control(ctl);
 512                 spin_lock(&cache->lock);
 513         }
 514
 515         if (cache->cached != BTRFS_CACHE_NO) {
 516                 spin_unlock(&cache->lock);
 517                 kfree(caching_ctl);
 518                 return 0;
 519         }
 520         WARN_ON(cache->caching_ctl);
 521         cache->caching_ctl = caching_ctl;
 522         cache->cached = BTRFS_CACHE_FAST;
 523         spin_unlock(&cache->lock);
 524
 525         /*
 526          * We can't do the read from on-disk cache during a commit since we need
 527          * to have the normal tree locking.  Also if we are currently trying to
 528          * allocate blocks for the tree root we can't do the fast caching since
 529          * we likely hold important locks.
 530          */
 531         if (trans && (!trans->transaction->in_commit) &&
 532             (root && root != root->fs_info->tree_root) &&
 533             btrfs_test_opt(root, SPACE_CACHE)) {
 534                 ret = load_free_space_cache(fs_info, cache);
 535
 536                 spin_lock(&cache->lock);
 537                 if (ret == 1) {
 538                         cache->caching_ctl = NULL;
 539                         cache->cached = BTRFS_CACHE_FINISHED;
 540                         cache->last_byte_to_unpin = (u64)-1;
 541                 } else {
 542                         if (load_cache_only) {
 543                                 cache->caching_ctl = NULL;
 544                                 cache->cached = BTRFS_CACHE_NO;
 545                         } else {
 546                                 cache->cached = BTRFS_CACHE_STARTED;
 547                         }
 548                 }
 549                 spin_unlock(&cache->lock);
 550                 wake_up(&caching_ctl->wait);
 551                 if (ret == 1) {
 552                         put_caching_control(caching_ctl);
 553                         free_excluded_extents(fs_info->extent_root, cache);
 554                         return 0;
 555                 }
 556         } else {
 557                 /*
 558                  * We are not going to do the fast caching, set cached to the
 559                  * appropriate value and wakeup any waiters.
 560                  */
 561                 spin_lock(&cache->lock);
 562                 if (load_cache_only) {
 563                         cache->caching_ctl = NULL;
 564                         cache->cached = BTRFS_CACHE_NO;
 565                 } else {
 566                         cache->cached = BTRFS_CACHE_STARTED;
 567                 }
 568                 spin_unlock(&cache->lock);
 569                 wake_up(&caching_ctl->wait);
 570         }
 571
 572         if (load_cache_only) {
 573                 put_caching_control(caching_ctl);
 574                 return 0;
 575         }
 576
 577         down_write(&fs_info->extent_commit_sem);
 578         atomic_inc(&caching_ctl->count);
 579         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 580         up_write(&fs_info->extent_commit_sem);
 581
 582         btrfs_get_block_group(cache);
 583
 584         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 585
 586         return ret;
 587 }
 588
 589 /*
 590  * return the block group that starts at or after bytenr
 591  */
 592 static struct btrfs_block_group_cache *
 593 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 594 {
 595         struct btrfs_block_group_cache *cache;
 596
 597         cache = block_group_cache_tree_search(info, bytenr, 0);
 598
 599         return cache;
 600 }
 601
 602 /*
 603  * return the block group that contains the given bytenr
 604  */
 605 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 606                                                  struct btrfs_fs_info *info,
 607                                                  u64 bytenr)
 608 {
 609         struct btrfs_block_group_cache *cache;
 610
 611         cache = block_group_cache_tree_search(info, bytenr, 1);
 612
 613         return cache;
 614 }
 615
 616 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 617                                                   u64 flags)
 618 {
 619         struct list_head *head = &info->space_info;
 620         struct btrfs_space_info *found;
 621
 622         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 623
 624         rcu_read_lock();
 625         list_for_each_entry_rcu(found, head, list) {
 626                 if (found->flags & flags) {
 627                         rcu_read_unlock();
 628                         return found;
 629                 }
 630         }
 631         rcu_read_unlock();
 632         return NULL;
 633 }
 634
 635 /*
 636  * after adding space to the filesystem, we need to clear the full flags
 637  * on all the space infos.
 638  */
 639 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 640 {
 641         struct list_head *head = &info->space_info;
 642         struct btrfs_space_info *found;
 643
 644         rcu_read_lock();
 645         list_for_each_entry_rcu(found, head, list)
 646                 found->full = 0;
 647         rcu_read_unlock();
 648 }
 649
 650 static u64 div_factor(u64 num, int factor)
 651 {
 652         if (factor == 10)
 653                 return num;
 654         num *= factor;
 655         do_div(num, 10);
 656         return num;
 657 }
 658
 659 static u64 div_factor_fine(u64 num, int factor)
 660 {
 661         if (factor == 100)
 662                 return num;
 663         num *= factor;
 664         do_div(num, 100);
 665         return num;
 666 }
 667
 668 u64 btrfs_find_block_group(struct btrfs_root *root,
 669                            u64 search_start, u64 search_hint, int owner)
 670 {
 671         struct btrfs_block_group_cache *cache;
 672         u64 used;
 673         u64 last = max(search_hint, search_start);
 674         u64 group_start = 0;
 675         int full_search = 0;
 676         int factor = 9;
 677         int wrapped = 0;
 678 again:
 679         while (1) {
 680                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 681                 if (!cache)
 682                         break;
 683
 684                 spin_lock(&cache->lock);
 685                 last = cache->key.objectid + cache->key.offset;
 686                 used = btrfs_block_group_used(&cache->item);
 687
 688                 if ((full_search || !cache->ro) &&
 689                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 690                         if (used + cache->pinned + cache->reserved <
 691                             div_factor(cache->key.offset, factor)) {
 692                                 group_start = cache->key.objectid;
 693                                 spin_unlock(&cache->lock);
 694                                 btrfs_put_block_group(cache);
 695                                 goto found;
 696                         }
 697                 }
 698                 spin_unlock(&cache->lock);
 699                 btrfs_put_block_group(cache);
 700                 cond_resched();
 701         }
 702         if (!wrapped) {
 703                 last = search_start;
 704                 wrapped = 1;
 705                 goto again;
 706         }
 707         if (!full_search && factor < 10) {
 708                 last = search_start;
 709                 full_search = 1;
 710                 factor = 10;
 711                 goto again;
 712         }
 713 found:
 714         return group_start;
 715 }
 716
 717 /* simple helper to search for an existing extent at a given offset */
 718 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 719 {
 720         int ret;
 721         struct btrfs_key key;
 722         struct btrfs_path *path;
 723
 724         path = btrfs_alloc_path();
 725         if (!path)
 726                 return -ENOMEM;
 727
 728         key.objectid = start;
 729         key.offset = len;
 730         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 731         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 732                                 0, 0);
 733         btrfs_free_path(path);
 734         return ret;
 735 }
 736
 737 /*
 738  * helper function to lookup reference count and flags of extent.
 739  *
 740  * the head node for delayed ref is used to store the sum of all the
 741  * reference count modifications queued up in the rbtree. the head
 742  * node may also store the extent flags to set. This way you can check
 743  * to see what the reference count and extent flags would be if all of
 744  * the delayed refs are not processed.
 745  */
 746 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 747                              struct btrfs_root *root, u64 bytenr,
 748                              u64 num_bytes, u64 *refs, u64 *flags)
 749 {
 750         struct btrfs_delayed_ref_head *head;
 751         struct btrfs_delayed_ref_root *delayed_refs;
 752         struct btrfs_path *path;
 753         struct btrfs_extent_item *ei;
 754         struct extent_buffer *leaf;
 755         struct btrfs_key key;
 756         u32 item_size;
 757         u64 num_refs;
 758         u64 extent_flags;
 759         int ret;
 760
 761         path = btrfs_alloc_path();
 762         if (!path)
 763                 return -ENOMEM;
 764
 765         key.objectid = bytenr;
 766         key.type = BTRFS_EXTENT_ITEM_KEY;
 767         key.offset = num_bytes;
 768         if (!trans) {
 769                 path->skip_locking = 1;
 770                 path->search_commit_root = 1;
 771         }
 772 again:
 773         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 774                                 &key, path, 0, 0);
 775         if (ret < 0)
 776                 goto out_free;
 777
 778         if (ret == 0) {
 779                 leaf = path->nodes[0];
 780                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 781                 if (item_size >= sizeof(*ei)) {
 782                         ei = btrfs_item_ptr(leaf, path->slots[0],
 783                                             struct btrfs_extent_item);
 784                         num_refs = btrfs_extent_refs(leaf, ei);
 785                         extent_flags = btrfs_extent_flags(leaf, ei);
 786                 } else {
 787 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 788                         struct btrfs_extent_item_v0 *ei0;
 789                         BUG_ON(item_size != sizeof(*ei0));
 790                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 791                                              struct btrfs_extent_item_v0);
 792                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 793                         /* FIXME: this isn't correct for data */
 794                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 795 #else
 796                         BUG();
 797 #endif
 798                 }
 799                 BUG_ON(num_refs == 0);
 800         } else {
 801                 num_refs = 0;
 802                 extent_flags = 0;
 803                 ret = 0;
 804         }
 805
 806         if (!trans)
 807                 goto out;
 808
 809         delayed_refs = &trans->transaction->delayed_refs;
 810         spin_lock(&delayed_refs->lock);
 811         head = btrfs_find_delayed_ref_head(trans, bytenr);
 812         if (head) {
 813                 if (!mutex_trylock(&head->mutex)) {
 814                         atomic_inc(&head->node.refs);
 815                         spin_unlock(&delayed_refs->lock);
 816
 817                         btrfs_release_path(path);
 818
 819                         /*
 820                          * Mutex was contended, block until it's released and try
 821                          * again
 822                          */
 823                         mutex_lock(&head->mutex);
 824                         mutex_unlock(&head->mutex);
 825                         btrfs_put_delayed_ref(&head->node);
 826                         goto again;
 827                 }
 828                 if (head->extent_op && head->extent_op->update_flags)
 829                         extent_flags |= head->extent_op->flags_to_set;
 830                 else
 831                         BUG_ON(num_refs == 0);
 832
 833                 num_refs += head->node.ref_mod;
 834                 mutex_unlock(&head->mutex);
 835         }
 836         spin_unlock(&delayed_refs->lock);
 837 out:
 838         WARN_ON(num_refs == 0);
 839         if (refs)
 840                 *refs = num_refs;
 841         if (flags)
 842                 *flags = extent_flags;
 843 out_free:
 844         btrfs_free_path(path);
 845         return ret;
 846 }
 847
 848 /*
 849  * Back reference rules.  Back refs have three main goals:
 850  *
 851  * 1) differentiate between all holders of references to an extent so that
 852  *    when a reference is dropped we can make sure it was a valid reference
 853  *    before freeing the extent.
 854  *
 855  * 2) Provide enough information to quickly find the holders of an extent
 856  *    if we notice a given block is corrupted or bad.
 857  *
 858  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 859  *    maintenance.  This is actually the same as #2, but with a slightly
 860  *    different use case.
 861  *
 862  * There are two kinds of back refs. The implicit back refs is optimized
 863  * for pointers in non-shared tree blocks. For a given pointer in a block,
 864  * back refs of this kind provide information about the block's owner tree
 865  * and the pointer's key. These information allow us to find the block by
 866  * b-tree searching. The full back refs is for pointers in tree blocks not
 867  * referenced by their owner trees. The location of tree block is recorded
 868  * in the back refs. Actually the full back refs is generic, and can be
 869  * used in all cases the implicit back refs is used. The major shortcoming
 870  * of the full back refs is its overhead. Every time a tree block gets
 871  * COWed, we have to update back refs entry for all pointers in it.
 872  *
 873  * For a newly allocated tree block, we use implicit back refs for
 874  * pointers in it. This means most tree related operations only involve
 875  * implicit back refs. For a tree block created in old transaction, the
 876  * only way to drop a reference to it is COW it. So we can detect the
 877  * event that tree block loses its owner tree's reference and do the
 878  * back refs conversion.
 879  *
 880  * When a tree block is COW'd through a tree, there are four cases:
 881  *
 882  * The reference count of the block is one and the tree is the block's
 883  * owner tree. Nothing to do in this case.
 884  *
 885  * The reference count of the block is one and the tree is not the
 886  * block's owner tree. In this case, full back refs is used for pointers
 887  * in the block. Remove these full back refs, add implicit back refs for
 888  * every pointers in the new block.
 889  *
 890  * The reference count of the block is greater than one and the tree is
 891  * the block's owner tree. In this case, implicit back refs is used for
 892  * pointers in the block. Add full back refs for every pointers in the
 893  * block, increase lower level extents' reference counts. The original
 894  * implicit back refs are entailed to the new block.
 895  *
 896  * The reference count of the block is greater than one and the tree is
 897  * not the block's owner tree. Add implicit back refs for every pointer in
 898  * the new block, increase lower level extents' reference count.
 899  *
 900  * Back Reference Key composing:
 901  *
 902  * The key objectid corresponds to the first byte in the extent,
 903  * The key type is used to differentiate between types of back refs.
 904  * There are different meanings of the key offset for different types
 905  * of back refs.
 906  *
 907  * File extents can be referenced by:
 908  *
 909  * - multiple snapshots, subvolumes, or different generations in one subvol
 910  * - different files inside a single subvolume
 911  * - different offsets inside a file (bookend extents in file.c)
 912  *
 913  * The extent ref structure for the implicit back refs has fields for:
 914  *
 915  * - Objectid of the subvolume root
 916  * - objectid of the file holding the reference
 917  * - original offset in the file
 918  * - how many bookend extents
 919  *
 920  * The key offset for the implicit back refs is hash of the first
 921  * three fields.
 922  *
 923  * The extent ref structure for the full back refs has field for:
 924  *
 925  * - number of pointers in the tree leaf
 926  *
 927  * The key offset for the implicit back refs is the first byte of
 928  * the tree leaf
 929  *
 930  * When a file extent is allocated, The implicit back refs is used.
 931  * the fields are filled in:
 932  *
 933  *     (root_key.objectid, inode objectid, offset in file, 1)
 934  *
 935  * When a file extent is removed file truncation, we find the
 936  * corresponding implicit back refs and check the following fields:
 937  *
 938  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 939  *
 940  * Btree extents can be referenced by:
 941  *
 942  * - Different subvolumes
 943  *
 944  * Both the implicit back refs and the full back refs for tree blocks
 945  * only consist of key. The key offset for the implicit back refs is
 946  * objectid of block's owner tree. The key offset for the full back refs
 947  * is the first byte of parent block.
 948  *
 949  * When implicit back refs is used, information about the lowest key and
 950  * level of the tree block are required. These information are stored in
 951  * tree block info structure.
 952  */
 953
 954 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 955 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 956                                   struct btrfs_root *root,
 957                                   struct btrfs_path *path,
 958                                   u64 owner, u32 extra_size)
 959 {
 960         struct btrfs_extent_item *item;
 961         struct btrfs_extent_item_v0 *ei0;
 962         struct btrfs_extent_ref_v0 *ref0;
 963         struct btrfs_tree_block_info *bi;
 964         struct extent_buffer *leaf;
 965         struct btrfs_key key;
 966         struct btrfs_key found_key;
 967         u32 new_size = sizeof(*item);
 968         u64 refs;
 969         int ret;
 970
 971         leaf = path->nodes[0];
 972         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 973
 974         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 975         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 976                              struct btrfs_extent_item_v0);
 977         refs = btrfs_extent_refs_v0(leaf, ei0);
 978
 979         if (owner == (u64)-1) {
 980                 while (1) {
 981                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 982                                 ret = btrfs_next_leaf(root, path);
 983                                 if (ret < 0)
 984                                         return ret;
 985                                 BUG_ON(ret > 0);
 986                                 leaf = path->nodes[0];
 987                         }
 988                         btrfs_item_key_to_cpu(leaf, &found_key,
 989                                               path->slots[0]);
 990                         BUG_ON(key.objectid != found_key.objectid);
 991                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 992                                 path->slots[0]++;
 993                                 continue;
 994                         }
 995                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 996                                               struct btrfs_extent_ref_v0);
 997                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 998                         break;
 999                 }
1000         }
1001         btrfs_release_path(path);
1002
1003         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1004                 new_size += sizeof(*bi);
1005
1006         new_size -= sizeof(*ei0);
1007         ret = btrfs_search_slot(trans, root, &key, path,
1008                                 new_size + extra_size, 1);
1009         if (ret < 0)
1010                 return ret;
1011         BUG_ON(ret);
1012
1013         ret = btrfs_extend_item(trans, root, path, new_size);
1014
1015         leaf = path->nodes[0];
1016         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1017         btrfs_set_extent_refs(leaf, item, refs);
1018         /* FIXME: get real generation */
1019         btrfs_set_extent_generation(leaf, item, 0);
1020         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1021                 btrfs_set_extent_flags(leaf, item,
1022                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1023                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1024                 bi = (struct btrfs_tree_block_info *)(item + 1);
1025                 /* FIXME: get first key of the block */
1026                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1027                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1028         } else {
1029                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1030         }
1031         btrfs_mark_buffer_dirty(leaf);
1032         return 0;
1033 }
1034 #endif
1035
1036 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1037 {
1038         u32 high_crc = ~(u32)0;
1039         u32 low_crc = ~(u32)0;
1040         __le64 lenum;
1041
1042         lenum = cpu_to_le64(root_objectid);
1043         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1044         lenum = cpu_to_le64(owner);
1045         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1046         lenum = cpu_to_le64(offset);
1047         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1048
1049         return ((u64)high_crc << 31) ^ (u64)low_crc;
1050 }
1051
1052 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1053                                      struct btrfs_extent_data_ref *ref)
1054 {
1055         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1056                                     btrfs_extent_data_ref_objectid(leaf, ref),
1057                                     btrfs_extent_data_ref_offset(leaf, ref));
1058 }
1059
1060 static int match_extent_data_ref(struct extent_buffer *leaf,
1061                                  struct btrfs_extent_data_ref *ref,
1062                                  u64 root_objectid, u64 owner, u64 offset)
1063 {
1064         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1065             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1066             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1067                 return 0;
1068         return 1;
1069 }
1070
1071 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1072                                            struct btrfs_root *root,
1073                                            struct btrfs_path *path,
1074                                            u64 bytenr, u64 parent,
1075                                            u64 root_objectid,
1076                                            u64 owner, u64 offset)
1077 {
1078         struct btrfs_key key;
1079         struct btrfs_extent_data_ref *ref;
1080         struct extent_buffer *leaf;
1081         u32 nritems;
1082         int ret;
1083         int recow;
1084         int err = -ENOENT;
1085
1086         key.objectid = bytenr;
1087         if (parent) {
1088                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1089                 key.offset = parent;
1090         } else {
1091                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1092                 key.offset = hash_extent_data_ref(root_objectid,
1093                                                   owner, offset);
1094         }
1095 again:
1096         recow = 0;
1097         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1098         if (ret < 0) {
1099                 err = ret;
1100                 goto fail;
1101         }
1102
1103         if (parent) {
1104                 if (!ret)
1105                         return 0;
1106 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1107                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1108                 btrfs_release_path(path);
1109                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1110                 if (ret < 0) {
1111                         err = ret;
1112                         goto fail;
1113                 }
1114                 if (!ret)
1115                         return 0;
1116 #endif
1117                 goto fail;
1118         }
1119
1120         leaf = path->nodes[0];
1121         nritems = btrfs_header_nritems(leaf);
1122         while (1) {
1123                 if (path->slots[0] >= nritems) {
1124                         ret = btrfs_next_leaf(root, path);
1125                         if (ret < 0)
1126                                 err = ret;
1127                         if (ret)
1128                                 goto fail;
1129
1130                         leaf = path->nodes[0];
1131                         nritems = btrfs_header_nritems(leaf);
1132                         recow = 1;
1133                 }
1134
1135                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1136                 if (key.objectid != bytenr ||
1137                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1138                         goto fail;
1139
1140                 ref = btrfs_item_ptr(leaf, path->slots[0],
1141                                      struct btrfs_extent_data_ref);
1142
1143                 if (match_extent_data_ref(leaf, ref, root_objectid,
1144                                           owner, offset)) {
1145                         if (recow) {
1146                                 btrfs_release_path(path);
1147                                 goto again;
1148                         }
1149                         err = 0;
1150                         break;
1151                 }
1152                 path->slots[0]++;
1153         }
1154 fail:
1155         return err;
1156 }
1157
1158 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1159                                            struct btrfs_root *root,
1160                                            struct btrfs_path *path,
1161                                            u64 bytenr, u64 parent,
1162                                            u64 root_objectid, u64 owner,
1163                                            u64 offset, int refs_to_add)
1164 {
1165         struct btrfs_key key;
1166         struct extent_buffer *leaf;
1167         u32 size;
1168         u32 num_refs;
1169         int ret;
1170
1171         key.objectid = bytenr;
1172         if (parent) {
1173                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1174                 key.offset = parent;
1175                 size = sizeof(struct btrfs_shared_data_ref);
1176         } else {
1177                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1178                 key.offset = hash_extent_data_ref(root_objectid,
1179                                                   owner, offset);
1180                 size = sizeof(struct btrfs_extent_data_ref);
1181         }
1182
1183         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1184         if (ret && ret != -EEXIST)
1185                 goto fail;
1186
1187         leaf = path->nodes[0];
1188         if (parent) {
1189                 struct btrfs_shared_data_ref *ref;
1190                 ref = btrfs_item_ptr(leaf, path->slots[0],
1191                                      struct btrfs_shared_data_ref);
1192                 if (ret == 0) {
1193                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1194                 } else {
1195                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1196                         num_refs += refs_to_add;
1197                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1198                 }
1199         } else {
1200                 struct btrfs_extent_data_ref *ref;
1201                 while (ret == -EEXIST) {
1202                         ref = btrfs_item_ptr(leaf, path->slots[0],
1203                                              struct btrfs_extent_data_ref);
1204                         if (match_extent_data_ref(leaf, ref, root_objectid,
1205                                                   owner, offset))
1206                                 break;
1207                         btrfs_release_path(path);
1208                         key.offset++;
1209                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1210                                                       size);
1211                         if (ret && ret != -EEXIST)
1212                                 goto fail;
1213
1214                         leaf = path->nodes[0];
1215                 }
1216                 ref = btrfs_item_ptr(leaf, path->slots[0],
1217                                      struct btrfs_extent_data_ref);
1218                 if (ret == 0) {
1219                         btrfs_set_extent_data_ref_root(leaf, ref,
1220                                                        root_objectid);
1221                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1222                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1223                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1224                 } else {
1225                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1226                         num_refs += refs_to_add;
1227                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1228                 }
1229         }
1230         btrfs_mark_buffer_dirty(leaf);
1231         ret = 0;
1232 fail:
1233         btrfs_release_path(path);
1234         return ret;
1235 }
1236
1237 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1238                                            struct btrfs_root *root,
1239                                            struct btrfs_path *path,
1240                                            int refs_to_drop)
1241 {
1242         struct btrfs_key key;
1243         struct btrfs_extent_data_ref *ref1 = NULL;
1244         struct btrfs_shared_data_ref *ref2 = NULL;
1245         struct extent_buffer *leaf;
1246         u32 num_refs = 0;
1247         int ret = 0;
1248
1249         leaf = path->nodes[0];
1250         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1251
1252         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1253                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1254                                       struct btrfs_extent_data_ref);
1255                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1256         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1257                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1258                                       struct btrfs_shared_data_ref);
1259                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1260 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1261         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1262                 struct btrfs_extent_ref_v0 *ref0;
1263                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1264                                       struct btrfs_extent_ref_v0);
1265                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1266 #endif
1267         } else {
1268                 BUG();
1269         }
1270
1271         BUG_ON(num_refs < refs_to_drop);
1272         num_refs -= refs_to_drop;
1273
1274         if (num_refs == 0) {
1275                 ret = btrfs_del_item(trans, root, path);
1276         } else {
1277                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1278                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1279                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1280                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1281 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1282                 else {
1283                         struct btrfs_extent_ref_v0 *ref0;
1284                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1285                                         struct btrfs_extent_ref_v0);
1286                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1287                 }
1288 #endif
1289                 btrfs_mark_buffer_dirty(leaf);
1290         }
1291         return ret;
1292 }
1293
1294 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1295                                           struct btrfs_path *path,
1296                                           struct btrfs_extent_inline_ref *iref)
1297 {
1298         struct btrfs_key key;
1299         struct extent_buffer *leaf;
1300         struct btrfs_extent_data_ref *ref1;
1301         struct btrfs_shared_data_ref *ref2;
1302         u32 num_refs = 0;
1303
1304         leaf = path->nodes[0];
1305         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1306         if (iref) {
1307                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1308                     BTRFS_EXTENT_DATA_REF_KEY) {
1309                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1310                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1311                 } else {
1312                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1313                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1314                 }
1315         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1316                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1317                                       struct btrfs_extent_data_ref);
1318                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1319         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1320                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1321                                       struct btrfs_shared_data_ref);
1322                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1323 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1324         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1325                 struct btrfs_extent_ref_v0 *ref0;
1326                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1327                                       struct btrfs_extent_ref_v0);
1328                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1329 #endif
1330         } else {
1331                 WARN_ON(1);
1332         }
1333         return num_refs;
1334 }
1335
1336 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1337                                           struct btrfs_root *root,
1338                                           struct btrfs_path *path,
1339                                           u64 bytenr, u64 parent,
1340                                           u64 root_objectid)
1341 {
1342         struct btrfs_key key;
1343         int ret;
1344
1345         key.objectid = bytenr;
1346         if (parent) {
1347                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1348                 key.offset = parent;
1349         } else {
1350                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1351                 key.offset = root_objectid;
1352         }
1353
1354         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1355         if (ret > 0)
1356                 ret = -ENOENT;
1357 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1358         if (ret == -ENOENT && parent) {
1359                 btrfs_release_path(path);
1360                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1361                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1362                 if (ret > 0)
1363                         ret = -ENOENT;
1364         }
1365 #endif
1366         return ret;
1367 }
1368
1369 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1370                                           struct btrfs_root *root,
1371                                           struct btrfs_path *path,
1372                                           u64 bytenr, u64 parent,
1373                                           u64 root_objectid)
1374 {
1375         struct btrfs_key key;
1376         int ret;
1377
1378         key.objectid = bytenr;
1379         if (parent) {
1380                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1381                 key.offset = parent;
1382         } else {
1383                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1384                 key.offset = root_objectid;
1385         }
1386
1387         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1388         btrfs_release_path(path);
1389         return ret;
1390 }
1391
1392 static inline int extent_ref_type(u64 parent, u64 owner)
1393 {
1394         int type;
1395         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1396                 if (parent > 0)
1397                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1398                 else
1399                         type = BTRFS_TREE_BLOCK_REF_KEY;
1400         } else {
1401                 if (parent > 0)
1402                         type = BTRFS_SHARED_DATA_REF_KEY;
1403                 else
1404                         type = BTRFS_EXTENT_DATA_REF_KEY;
1405         }
1406         return type;
1407 }
1408
1409 static int find_next_key(struct btrfs_path *path, int level,
1410                          struct btrfs_key *key)
1411
1412 {
1413         for (; level < BTRFS_MAX_LEVEL; level++) {
1414                 if (!path->nodes[level])
1415                         break;
1416                 if (path->slots[level] + 1 >=
1417                     btrfs_header_nritems(path->nodes[level]))
1418                         continue;
1419                 if (level == 0)
1420                         btrfs_item_key_to_cpu(path->nodes[level], key,
1421                                               path->slots[level] + 1);
1422                 else
1423                         btrfs_node_key_to_cpu(path->nodes[level], key,
1424                                               path->slots[level] + 1);
1425                 return 0;
1426         }
1427         return 1;
1428 }
1429
1430 /*
1431  * look for inline back ref. if back ref is found, *ref_ret is set
1432  * to the address of inline back ref, and 0 is returned.
1433  *
1434  * if back ref isn't found, *ref_ret is set to the address where it
1435  * should be inserted, and -ENOENT is returned.
1436  *
1437  * if insert is true and there are too many inline back refs, the path
1438  * points to the extent item, and -EAGAIN is returned.
1439  *
1440  * NOTE: inline back refs are ordered in the same way that back ref
1441  *       items in the tree are ordered.
1442  */
1443 static noinline_for_stack
1444 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1445                                  struct btrfs_root *root,
1446                                  struct btrfs_path *path,
1447                                  struct btrfs_extent_inline_ref **ref_ret,
1448                                  u64 bytenr, u64 num_bytes,
1449                                  u64 parent, u64 root_objectid,
1450                                  u64 owner, u64 offset, int insert)
1451 {
1452         struct btrfs_key key;
1453         struct extent_buffer *leaf;
1454         struct btrfs_extent_item *ei;
1455         struct btrfs_extent_inline_ref *iref;
1456         u64 flags;
1457         u64 item_size;
1458         unsigned long ptr;
1459         unsigned long end;
1460         int extra_size;
1461         int type;
1462         int want;
1463         int ret;
1464         int err = 0;
1465
1466         key.objectid = bytenr;
1467         key.type = BTRFS_EXTENT_ITEM_KEY;
1468         key.offset = num_bytes;
1469
1470         want = extent_ref_type(parent, owner);
1471         if (insert) {
1472                 extra_size = btrfs_extent_inline_ref_size(want);
1473                 path->keep_locks = 1;
1474         } else
1475                 extra_size = -1;
1476         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1477         if (ret < 0) {
1478                 err = ret;
1479                 goto out;
1480         }
1481         BUG_ON(ret);
1482
1483         leaf = path->nodes[0];
1484         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1485 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1486         if (item_size < sizeof(*ei)) {
1487                 if (!insert) {
1488                         err = -ENOENT;
1489                         goto out;
1490                 }
1491                 ret = convert_extent_item_v0(trans, root, path, owner,
1492                                              extra_size);
1493                 if (ret < 0) {
1494                         err = ret;
1495                         goto out;
1496                 }
1497                 leaf = path->nodes[0];
1498                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1499         }
1500 #endif
1501         BUG_ON(item_size < sizeof(*ei));
1502
1503         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1504         flags = btrfs_extent_flags(leaf, ei);
1505
1506         ptr = (unsigned long)(ei + 1);
1507         end = (unsigned long)ei + item_size;
1508
1509         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1510                 ptr += sizeof(struct btrfs_tree_block_info);
1511                 BUG_ON(ptr > end);
1512         } else {
1513                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1514         }
1515
1516         err = -ENOENT;
1517         while (1) {
1518                 if (ptr >= end) {
1519                         WARN_ON(ptr > end);
1520                         break;
1521                 }
1522                 iref = (struct btrfs_extent_inline_ref *)ptr;
1523                 type = btrfs_extent_inline_ref_type(leaf, iref);
1524                 if (want < type)
1525                         break;
1526                 if (want > type) {
1527                         ptr += btrfs_extent_inline_ref_size(type);
1528                         continue;
1529                 }
1530
1531                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1532                         struct btrfs_extent_data_ref *dref;
1533                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1534                         if (match_extent_data_ref(leaf, dref, root_objectid,
1535                                                   owner, offset)) {
1536                                 err = 0;
1537                                 break;
1538                         }
1539                         if (hash_extent_data_ref_item(leaf, dref) <
1540                             hash_extent_data_ref(root_objectid, owner, offset))
1541                                 break;
1542                 } else {
1543                         u64 ref_offset;
1544                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1545                         if (parent > 0) {
1546                                 if (parent == ref_offset) {
1547                                         err = 0;
1548                                         break;
1549                                 }
1550                                 if (ref_offset < parent)
1551                                         break;
1552                         } else {
1553                                 if (root_objectid == ref_offset) {
1554                                         err = 0;
1555                                         break;
1556                                 }
1557                                 if (ref_offset < root_objectid)
1558                                         break;
1559                         }
1560                 }
1561                 ptr += btrfs_extent_inline_ref_size(type);
1562         }
1563         if (err == -ENOENT && insert) {
1564                 if (item_size + extra_size >=
1565                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1566                         err = -EAGAIN;
1567                         goto out;
1568                 }
1569                 /*
1570                  * To add new inline back ref, we have to make sure
1571                  * there is no corresponding back ref item.
1572                  * For simplicity, we just do not add new inline back
1573                  * ref if there is any kind of item for this block
1574                  */
1575                 if (find_next_key(path, 0, &key) == 0 &&
1576                     key.objectid == bytenr &&
1577                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1578                         err = -EAGAIN;
1579                         goto out;
1580                 }
1581         }
1582         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1583 out:
1584         if (insert) {
1585                 path->keep_locks = 0;
1586                 btrfs_unlock_up_safe(path, 1);
1587         }
1588         return err;
1589 }
1590
1591 /*
1592  * helper to add new inline back ref
1593  */
1594 static noinline_for_stack
1595 int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1596                                 struct btrfs_root *root,
1597                                 struct btrfs_path *path,
1598                                 struct btrfs_extent_inline_ref *iref,
1599                                 u64 parent, u64 root_objectid,
1600                                 u64 owner, u64 offset, int refs_to_add,
1601                                 struct btrfs_delayed_extent_op *extent_op)
1602 {
1603         struct extent_buffer *leaf;
1604         struct btrfs_extent_item *ei;
1605         unsigned long ptr;
1606         unsigned long end;
1607         unsigned long item_offset;
1608         u64 refs;
1609         int size;
1610         int type;
1611         int ret;
1612
1613         leaf = path->nodes[0];
1614         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1615         item_offset = (unsigned long)iref - (unsigned long)ei;
1616
1617         type = extent_ref_type(parent, owner);
1618         size = btrfs_extent_inline_ref_size(type);
1619
1620         ret = btrfs_extend_item(trans, root, path, size);
1621
1622         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1623         refs = btrfs_extent_refs(leaf, ei);
1624         refs += refs_to_add;
1625         btrfs_set_extent_refs(leaf, ei, refs);
1626         if (extent_op)
1627                 __run_delayed_extent_op(extent_op, leaf, ei);
1628
1629         ptr = (unsigned long)ei + item_offset;
1630         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1631         if (ptr < end - size)
1632                 memmove_extent_buffer(leaf, ptr + size, ptr,
1633                                       end - size - ptr);
1634
1635         iref = (struct btrfs_extent_inline_ref *)ptr;
1636         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1637         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1638                 struct btrfs_extent_data_ref *dref;
1639                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1640                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1641                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1642                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1643                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1644         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1645                 struct btrfs_shared_data_ref *sref;
1646                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1647                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1648                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1649         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1650                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1651         } else {
1652                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1653         }
1654         btrfs_mark_buffer_dirty(leaf);
1655         return 0;
1656 }
1657
1658 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1659                                  struct btrfs_root *root,
1660                                  struct btrfs_path *path,
1661                                  struct btrfs_extent_inline_ref **ref_ret,
1662                                  u64 bytenr, u64 num_bytes, u64 parent,
1663                                  u64 root_objectid, u64 owner, u64 offset)
1664 {
1665         int ret;
1666
1667         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1668                                            bytenr, num_bytes, parent,
1669                                            root_objectid, owner, offset, 0);
1670         if (ret != -ENOENT)
1671                 return ret;
1672
1673         btrfs_release_path(path);
1674         *ref_ret = NULL;
1675
1676         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1677                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1678                                             root_objectid);
1679         } else {
1680                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1681                                              root_objectid, owner, offset);
1682         }
1683         return ret;
1684 }
1685
1686 /*
1687  * helper to update/remove inline back ref
1688  */
1689 static noinline_for_stack
1690 int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1691                                  struct btrfs_root *root,
1692                                  struct btrfs_path *path,
1693                                  struct btrfs_extent_inline_ref *iref,
1694                                  int refs_to_mod,
1695                                  struct btrfs_delayed_extent_op *extent_op)
1696 {
1697         struct extent_buffer *leaf;
1698         struct btrfs_extent_item *ei;
1699         struct btrfs_extent_data_ref *dref = NULL;
1700         struct btrfs_shared_data_ref *sref = NULL;
1701         unsigned long ptr;
1702         unsigned long end;
1703         u32 item_size;
1704         int size;
1705         int type;
1706         int ret;
1707         u64 refs;
1708
1709         leaf = path->nodes[0];
1710         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1711         refs = btrfs_extent_refs(leaf, ei);
1712         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1713         refs += refs_to_mod;
1714         btrfs_set_extent_refs(leaf, ei, refs);
1715         if (extent_op)
1716                 __run_delayed_extent_op(extent_op, leaf, ei);
1717
1718         type = btrfs_extent_inline_ref_type(leaf, iref);
1719
1720         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1721                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1722                 refs = btrfs_extent_data_ref_count(leaf, dref);
1723         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1724                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1725                 refs = btrfs_shared_data_ref_count(leaf, sref);
1726         } else {
1727                 refs = 1;
1728                 BUG_ON(refs_to_mod != -1);
1729         }
1730
1731         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1732         refs += refs_to_mod;
1733
1734         if (refs > 0) {
1735                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1736                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1737                 else
1738                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1739         } else {
1740                 size =  btrfs_extent_inline_ref_size(type);
1741                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1742                 ptr = (unsigned long)iref;
1743                 end = (unsigned long)ei + item_size;
1744                 if (ptr + size < end)
1745                         memmove_extent_buffer(leaf, ptr, ptr + size,
1746                                               end - ptr - size);
1747                 item_size -= size;
1748                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1749         }
1750         btrfs_mark_buffer_dirty(leaf);
1751         return 0;
1752 }
1753
1754 static noinline_for_stack
1755 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1756                                  struct btrfs_root *root,
1757                                  struct btrfs_path *path,
1758                                  u64 bytenr, u64 num_bytes, u64 parent,
1759                                  u64 root_objectid, u64 owner,
1760                                  u64 offset, int refs_to_add,
1761                                  struct btrfs_delayed_extent_op *extent_op)
1762 {
1763         struct btrfs_extent_inline_ref *iref;
1764         int ret;
1765
1766         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1767                                            bytenr, num_bytes, parent,
1768                                            root_objectid, owner, offset, 1);
1769         if (ret == 0) {
1770                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1771                 ret = update_inline_extent_backref(trans, root, path, iref,
1772                                                    refs_to_add, extent_op);
1773         } else if (ret == -ENOENT) {
1774                 ret = setup_inline_extent_backref(trans, root, path, iref,
1775                                                   parent, root_objectid,
1776                                                   owner, offset, refs_to_add,
1777                                                   extent_op);
1778         }
1779         return ret;
1780 }
1781
1782 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1783                                  struct btrfs_root *root,
1784                                  struct btrfs_path *path,
1785                                  u64 bytenr, u64 parent, u64 root_objectid,
1786                                  u64 owner, u64 offset, int refs_to_add)
1787 {
1788         int ret;
1789         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1790                 BUG_ON(refs_to_add != 1);
1791                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1792                                             parent, root_objectid);
1793         } else {
1794                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1795                                              parent, root_objectid,
1796                                              owner, offset, refs_to_add);
1797         }
1798         return ret;
1799 }
1800
1801 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1802                                  struct btrfs_root *root,
1803                                  struct btrfs_path *path,
1804                                  struct btrfs_extent_inline_ref *iref,
1805                                  int refs_to_drop, int is_data)
1806 {
1807         int ret;
1808
1809         BUG_ON(!is_data && refs_to_drop != 1);
1810         if (iref) {
1811                 ret = update_inline_extent_backref(trans, root, path, iref,
1812                                                    -refs_to_drop, NULL);
1813         } else if (is_data) {
1814                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1815         } else {
1816                 ret = btrfs_del_item(trans, root, path);
1817         }
1818         return ret;
1819 }
1820
1821 static int btrfs_issue_discard(struct block_device *bdev,
1822                                 u64 start, u64 len)
1823 {
1824         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1825 }
1826
1827 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1828                                 u64 num_bytes, u64 *actual_bytes)
1829 {
1830         int ret;
1831         u64 discarded_bytes = 0;
1832         struct btrfs_bio *bbio = NULL;
1833
1834
1835         /* Tell the block device(s) that the sectors can be discarded */
1836         ret = btrfs_map_block(&root->fs_info->mapping_tree, REQ_DISCARD,
1837                               bytenr, &num_bytes, &bbio, 0);
1838         if (!ret) {
1839                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1840                 int i;
1841
1842
1843                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1844                         if (!stripe->dev->can_discard)
1845                                 continue;
1846
1847                         ret = btrfs_issue_discard(stripe->dev->bdev,
1848                                                   stripe->physical,
1849                                                   stripe->length);
1850                         if (!ret)
1851                                 discarded_bytes += stripe->length;
1852                         else if (ret != -EOPNOTSUPP)
1853                                 break;
1854
1855                         /*
1856                          * Just in case we get back EOPNOTSUPP for some reason,
1857                          * just ignore the return value so we don't screw up
1858                          * people calling discard_extent.
1859                          */
1860                         ret = 0;
1861                 }
1862                 kfree(bbio);
1863         }
1864
1865         if (actual_bytes)
1866                 *actual_bytes = discarded_bytes;
1867
1868
1869         return ret;
1870 }
1871
1872 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1873                          struct btrfs_root *root,
1874                          u64 bytenr, u64 num_bytes, u64 parent,
1875                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1876 {
1877         int ret;
1878         struct btrfs_fs_info *fs_info = root->fs_info;
1879
1880         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1881                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1882
1883         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1884                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1885                                         num_bytes,
1886                                         parent, root_objectid, (int)owner,
1887                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1888         } else {
1889                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1890                                         num_bytes,
1891                                         parent, root_objectid, owner, offset,
1892                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1893         }
1894         return ret;
1895 }
1896
1897 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1898                                   struct btrfs_root *root,
1899                                   u64 bytenr, u64 num_bytes,
1900                                   u64 parent, u64 root_objectid,
1901                                   u64 owner, u64 offset, int refs_to_add,
1902                                   struct btrfs_delayed_extent_op *extent_op)
1903 {
1904         struct btrfs_path *path;
1905         struct extent_buffer *leaf;
1906         struct btrfs_extent_item *item;
1907         u64 refs;
1908         int ret;
1909         int err = 0;
1910
1911         path = btrfs_alloc_path();
1912         if (!path)
1913                 return -ENOMEM;
1914
1915         path->reada = 1;
1916         path->leave_spinning = 1;
1917         /* this will setup the path even if it fails to insert the back ref */
1918         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1919                                            path, bytenr, num_bytes, parent,
1920                                            root_objectid, owner, offset,
1921                                            refs_to_add, extent_op);
1922         if (ret == 0)
1923                 goto out;
1924
1925         if (ret != -EAGAIN) {
1926                 err = ret;
1927                 goto out;
1928         }
1929
1930         leaf = path->nodes[0];
1931         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1932         refs = btrfs_extent_refs(leaf, item);
1933         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1934         if (extent_op)
1935                 __run_delayed_extent_op(extent_op, leaf, item);
1936
1937         btrfs_mark_buffer_dirty(leaf);
1938         btrfs_release_path(path);
1939
1940         path->reada = 1;
1941         path->leave_spinning = 1;
1942
1943         /* now insert the actual backref */
1944         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1945                                     path, bytenr, parent, root_objectid,
1946                                     owner, offset, refs_to_add);
1947         BUG_ON(ret);
1948 out:
1949         btrfs_free_path(path);
1950         return err;
1951 }
1952
1953 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1954                                 struct btrfs_root *root,
1955                                 struct btrfs_delayed_ref_node *node,
1956                                 struct btrfs_delayed_extent_op *extent_op,
1957                                 int insert_reserved)
1958 {
1959         int ret = 0;
1960         struct btrfs_delayed_data_ref *ref;
1961         struct btrfs_key ins;
1962         u64 parent = 0;
1963         u64 ref_root = 0;
1964         u64 flags = 0;
1965
1966         ins.objectid = node->bytenr;
1967         ins.offset = node->num_bytes;
1968         ins.type = BTRFS_EXTENT_ITEM_KEY;
1969
1970         ref = btrfs_delayed_node_to_data_ref(node);
1971         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1972                 parent = ref->parent;
1973         else
1974                 ref_root = ref->root;
1975
1976         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1977                 if (extent_op) {
1978                         BUG_ON(extent_op->update_key);
1979                         flags |= extent_op->flags_to_set;
1980                 }
1981                 ret = alloc_reserved_file_extent(trans, root,
1982                                                  parent, ref_root, flags,
1983                                                  ref->objectid, ref->offset,
1984                                                  &ins, node->ref_mod);
1985         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1986                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1987                                              node->num_bytes, parent,
1988                                              ref_root, ref->objectid,
1989                                              ref->offset, node->ref_mod,
1990                                              extent_op);
1991         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1992                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1993                                           node->num_bytes, parent,
1994                                           ref_root, ref->objectid,
1995                                           ref->offset, node->ref_mod,
1996                                           extent_op);
1997         } else {
1998                 BUG();
1999         }
2000         return ret;
2001 }
2002
2003 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2004                                     struct extent_buffer *leaf,
2005                                     struct btrfs_extent_item *ei)
2006 {
2007         u64 flags = btrfs_extent_flags(leaf, ei);
2008         if (extent_op->update_flags) {
2009                 flags |= extent_op->flags_to_set;
2010                 btrfs_set_extent_flags(leaf, ei, flags);
2011         }
2012
2013         if (extent_op->update_key) {
2014                 struct btrfs_tree_block_info *bi;
2015                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2016                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2017                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2018         }
2019 }
2020
2021 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2022                                  struct btrfs_root *root,
2023                                  struct btrfs_delayed_ref_node *node,
2024                                  struct btrfs_delayed_extent_op *extent_op)
2025 {
2026         struct btrfs_key key;
2027         struct btrfs_path *path;
2028         struct btrfs_extent_item *ei;
2029         struct extent_buffer *leaf;
2030         u32 item_size;
2031         int ret;
2032         int err = 0;
2033
2034         path = btrfs_alloc_path();
2035         if (!path)
2036                 return -ENOMEM;
2037
2038         key.objectid = node->bytenr;
2039         key.type = BTRFS_EXTENT_ITEM_KEY;
2040         key.offset = node->num_bytes;
2041
2042         path->reada = 1;
2043         path->leave_spinning = 1;
2044         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2045                                 path, 0, 1);
2046         if (ret < 0) {
2047                 err = ret;
2048                 goto out;
2049         }
2050         if (ret > 0) {
2051                 err = -EIO;
2052                 goto out;
2053         }
2054
2055         leaf = path->nodes[0];
2056         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2057 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2058         if (item_size < sizeof(*ei)) {
2059                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2060                                              path, (u64)-1, 0);
2061                 if (ret < 0) {
2062                         err = ret;
2063                         goto out;
2064                 }
2065                 leaf = path->nodes[0];
2066                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2067         }
2068 #endif
2069         BUG_ON(item_size < sizeof(*ei));
2070         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2071         __run_delayed_extent_op(extent_op, leaf, ei);
2072
2073         btrfs_mark_buffer_dirty(leaf);
2074 out:
2075         btrfs_free_path(path);
2076         return err;
2077 }
2078
2079 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2080                                 struct btrfs_root *root,
2081                                 struct btrfs_delayed_ref_node *node,
2082                                 struct btrfs_delayed_extent_op *extent_op,
2083                                 int insert_reserved)
2084 {
2085         int ret = 0;
2086         struct btrfs_delayed_tree_ref *ref;
2087         struct btrfs_key ins;
2088         u64 parent = 0;
2089         u64 ref_root = 0;
2090
2091         ins.objectid = node->bytenr;
2092         ins.offset = node->num_bytes;
2093         ins.type = BTRFS_EXTENT_ITEM_KEY;
2094
2095         ref = btrfs_delayed_node_to_tree_ref(node);
2096         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2097                 parent = ref->parent;
2098         else
2099                 ref_root = ref->root;
2100
2101         BUG_ON(node->ref_mod != 1);
2102         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2103                 BUG_ON(!extent_op || !extent_op->update_flags ||
2104                        !extent_op->update_key);
2105                 ret = alloc_reserved_tree_block(trans, root,
2106                                                 parent, ref_root,
2107                                                 extent_op->flags_to_set,
2108                                                 &extent_op->key,
2109                                                 ref->level, &ins);
2110         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2111                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2112                                              node->num_bytes, parent, ref_root,
2113                                              ref->level, 0, 1, extent_op);
2114         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2115                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2116                                           node->num_bytes, parent, ref_root,
2117                                           ref->level, 0, 1, extent_op);
2118         } else {
2119                 BUG();
2120         }
2121         return ret;
2122 }
2123
2124 /* helper function to actually process a single delayed ref entry */
2125 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2126                                struct btrfs_root *root,
2127                                struct btrfs_delayed_ref_node *node,
2128                                struct btrfs_delayed_extent_op *extent_op,
2129                                int insert_reserved)
2130 {
2131         int ret;
2132         if (btrfs_delayed_ref_is_head(node)) {
2133                 struct btrfs_delayed_ref_head *head;
2134                 /*
2135                  * we've hit the end of the chain and we were supposed
2136                  * to insert this extent into the tree.  But, it got
2137                  * deleted before we ever needed to insert it, so all
2138                  * we have to do is clean up the accounting
2139                  */
2140                 BUG_ON(extent_op);
2141                 head = btrfs_delayed_node_to_head(node);
2142                 if (insert_reserved) {
2143                         btrfs_pin_extent(root, node->bytenr,
2144                                          node->num_bytes, 1);
2145                         if (head->is_data) {
2146                                 ret = btrfs_del_csums(trans, root,
2147                                                       node->bytenr,
2148                                                       node->num_bytes);
2149                                 BUG_ON(ret);
2150                         }
2151                 }
2152                 mutex_unlock(&head->mutex);
2153                 return 0;
2154         }
2155
2156         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2157             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2158                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2159                                            insert_reserved);
2160         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2161                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2162                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2163                                            insert_reserved);
2164         else
2165                 BUG();
2166         return ret;
2167 }
2168
2169 static noinline struct btrfs_delayed_ref_node *
2170 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2171 {
2172         struct rb_node *node;
2173         struct btrfs_delayed_ref_node *ref;
2174         int action = BTRFS_ADD_DELAYED_REF;
2175 again:
2176         /*
2177          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2178          * this prevents ref count from going down to zero when
2179          * there still are pending delayed ref.
2180          */
2181         node = rb_prev(&head->node.rb_node);
2182         while (1) {
2183                 if (!node)
2184                         break;
2185                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2186                                 rb_node);
2187                 if (ref->bytenr != head->node.bytenr)
2188                         break;
2189                 if (ref->action == action)
2190                         return ref;
2191                 node = rb_prev(node);
2192         }
2193         if (action == BTRFS_ADD_DELAYED_REF) {
2194                 action = BTRFS_DROP_DELAYED_REF;
2195                 goto again;
2196         }
2197         return NULL;
2198 }
2199
2200 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2201                                        struct btrfs_root *root,
2202                                        struct list_head *cluster)
2203 {
2204         struct btrfs_delayed_ref_root *delayed_refs;
2205         struct btrfs_delayed_ref_node *ref;
2206         struct btrfs_delayed_ref_head *locked_ref = NULL;
2207         struct btrfs_delayed_extent_op *extent_op;
2208         int ret;
2209         int count = 0;
2210         int must_insert_reserved = 0;
2211
2212         delayed_refs = &trans->transaction->delayed_refs;
2213         while (1) {
2214                 if (!locked_ref) {
2215                         /* pick a new head ref from the cluster list */
2216                         if (list_empty(cluster))
2217                                 break;
2218
2219                         locked_ref = list_entry(cluster->next,
2220                                      struct btrfs_delayed_ref_head, cluster);
2221
2222                         /* grab the lock that says we are going to process
2223                          * all the refs for this head */
2224                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2225
2226                         /*
2227                          * we may have dropped the spin lock to get the head
2228                          * mutex lock, and that might have given someone else
2229                          * time to free the head.  If that's true, it has been
2230                          * removed from our list and we can move on.
2231                          */
2232                         if (ret == -EAGAIN) {
2233                                 locked_ref = NULL;
2234                                 count++;
2235                                 continue;
2236                         }
2237                 }
2238
2239                 /*
2240                  * locked_ref is the head node, so we have to go one
2241                  * node back for any delayed ref updates
2242                  */
2243                 ref = select_delayed_ref(locked_ref);
2244
2245                 if (ref && ref->seq &&
2246                     btrfs_check_delayed_seq(delayed_refs, ref->seq)) {
2247                         /*
2248                          * there are still refs with lower seq numbers in the
2249                          * process of being added. Don't run this ref yet.
2250                          */
2251                         list_del_init(&locked_ref->cluster);
2252                         mutex_unlock(&locked_ref->mutex);
2253                         locked_ref = NULL;
2254                         delayed_refs->num_heads_ready++;
2255                         spin_unlock(&delayed_refs->lock);
2256                         cond_resched();
2257                         spin_lock(&delayed_refs->lock);
2258                         continue;
2259                 }
2260
2261                 /*
2262                  * record the must insert reserved flag before we
2263                  * drop the spin lock.
2264                  */
2265                 must_insert_reserved = locked_ref->must_insert_reserved;
2266                 locked_ref->must_insert_reserved = 0;
2267
2268                 extent_op = locked_ref->extent_op;
2269                 locked_ref->extent_op = NULL;
2270
2271                 if (!ref) {
2272                         /* All delayed refs have been processed, Go ahead
2273                          * and send the head node to run_one_delayed_ref,
2274                          * so that any accounting fixes can happen
2275                          */
2276                         ref = &locked_ref->node;
2277
2278                         if (extent_op && must_insert_reserved) {
2279                                 kfree(extent_op);
2280                                 extent_op = NULL;
2281                         }
2282
2283                         if (extent_op) {
2284                                 spin_unlock(&delayed_refs->lock);
2285
2286                                 ret = run_delayed_extent_op(trans, root,
2287                                                             ref, extent_op);
2288                                 BUG_ON(ret);
2289                                 kfree(extent_op);
2290
2291                                 goto next;
2292                         }
2293
2294                         list_del_init(&locked_ref->cluster);
2295                         locked_ref = NULL;
2296                 }
2297
2298                 ref->in_tree = 0;
2299                 rb_erase(&ref->rb_node, &delayed_refs->root);
2300                 delayed_refs->num_entries--;
2301                 /*
2302                  * we modified num_entries, but as we're currently running
2303                  * delayed refs, skip
2304                  *     wake_up(&delayed_refs->seq_wait);
2305                  * here.
2306                  */
2307                 spin_unlock(&delayed_refs->lock);
2308
2309                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2310                                           must_insert_reserved);
2311                 BUG_ON(ret);
2312
2313                 btrfs_put_delayed_ref(ref);
2314                 kfree(extent_op);
2315                 count++;
2316 next:
2317                 do_chunk_alloc(trans, root->fs_info->extent_root,
2318                                2 * 1024 * 1024,
2319                                btrfs_get_alloc_profile(root, 0),
2320                                CHUNK_ALLOC_NO_FORCE);
2321                 cond_resched();
2322                 spin_lock(&delayed_refs->lock);
2323         }
2324         return count;
2325 }
2326
2327
2328 static void wait_for_more_refs(struct btrfs_delayed_ref_root *delayed_refs,
2329                         unsigned long num_refs)
2330 {
2331         struct list_head *first_seq = delayed_refs->seq_head.next;
2332
2333         spin_unlock(&delayed_refs->lock);
2334         pr_debug("waiting for more refs (num %ld, first %p)\n",
2335                  num_refs, first_seq);
2336         wait_event(delayed_refs->seq_wait,
2337                    num_refs != delayed_refs->num_entries ||
2338                    delayed_refs->seq_head.next != first_seq);
2339         pr_debug("done waiting for more refs (num %ld, first %p)\n",
2340                  delayed_refs->num_entries, delayed_refs->seq_head.next);
2341         spin_lock(&delayed_refs->lock);
2342 }
2343
2344 /*
2345  * this starts processing the delayed reference count updates and
2346  * extent insertions we have queued up so far.  count can be
2347  * 0, which means to process everything in the tree at the start
2348  * of the run (but not newly added entries), or it can be some target
2349  * number you'd like to process.
2350  */
2351 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2352                            struct btrfs_root *root, unsigned long count)
2353 {
2354         struct rb_node *node;
2355         struct btrfs_delayed_ref_root *delayed_refs;
2356         struct btrfs_delayed_ref_node *ref;
2357         struct list_head cluster;
2358         int ret;
2359         u64 delayed_start;
2360         int run_all = count == (unsigned long)-1;
2361         int run_most = 0;
2362         unsigned long num_refs = 0;
2363         int consider_waiting;
2364
2365         if (root == root->fs_info->extent_root)
2366                 root = root->fs_info->tree_root;
2367
2368         do_chunk_alloc(trans, root->fs_info->extent_root,
2369                        2 * 1024 * 1024, btrfs_get_alloc_profile(root, 0),
2370                        CHUNK_ALLOC_NO_FORCE);
2371
2372         delayed_refs = &trans->transaction->delayed_refs;
2373         INIT_LIST_HEAD(&cluster);
2374 again:
2375         consider_waiting = 0;
2376         spin_lock(&delayed_refs->lock);
2377         if (count == 0) {
2378                 count = delayed_refs->num_entries * 2;
2379                 run_most = 1;
2380         }
2381         while (1) {
2382                 if (!(run_all || run_most) &&
2383                     delayed_refs->num_heads_ready < 64)
2384                         break;
2385
2386                 /*
2387                  * go find something we can process in the rbtree.  We start at
2388                  * the beginning of the tree, and then build a cluster
2389                  * of refs to process starting at the first one we are able to
2390                  * lock
2391                  */
2392                 delayed_start = delayed_refs->run_delayed_start;
2393                 ret = btrfs_find_ref_cluster(trans, &cluster,
2394                                              delayed_refs->run_delayed_start);
2395                 if (ret)
2396                         break;
2397
2398                 if (delayed_start >= delayed_refs->run_delayed_start) {
2399                         if (consider_waiting == 0) {
2400                                 /*
2401                                  * btrfs_find_ref_cluster looped. let's do one
2402                                  * more cycle. if we don't run any delayed ref
2403                                  * during that cycle (because we can't because
2404                                  * all of them are blocked) and if the number of
2405                                  * refs doesn't change, we avoid busy waiting.
2406                                  */
2407                                 consider_waiting = 1;
2408                                 num_refs = delayed_refs->num_entries;
2409                         } else {
2410                                 wait_for_more_refs(delayed_refs, num_refs);
2411                                 /*
2412                                  * after waiting, things have changed. we
2413                                  * dropped the lock and someone else might have
2414                                  * run some refs, built new clusters and so on.
2415                                  * therefore, we restart staleness detection.
2416                                  */
2417                                 consider_waiting = 0;
2418                         }
2419                 }
2420
2421                 ret = run_clustered_refs(trans, root, &cluster);
2422                 BUG_ON(ret < 0);
2423
2424                 count -= min_t(unsigned long, ret, count);
2425
2426                 if (count == 0)
2427                         break;
2428
2429                 if (ret || delayed_refs->run_delayed_start == 0) {
2430                         /* refs were run, let's reset staleness detection */
2431                         consider_waiting = 0;
2432                 }
2433         }
2434
2435         if (run_all) {
2436                 node = rb_first(&delayed_refs->root);
2437                 if (!node)
2438                         goto out;
2439                 count = (unsigned long)-1;
2440
2441                 while (node) {
2442                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2443                                        rb_node);
2444                         if (btrfs_delayed_ref_is_head(ref)) {
2445                                 struct btrfs_delayed_ref_head *head;
2446
2447                                 head = btrfs_delayed_node_to_head(ref);
2448                                 atomic_inc(&ref->refs);
2449
2450                                 spin_unlock(&delayed_refs->lock);
2451                                 /*
2452                                  * Mutex was contended, block until it's
2453                                  * released and try again
2454                                  */
2455                                 mutex_lock(&head->mutex);
2456                                 mutex_unlock(&head->mutex);
2457
2458                                 btrfs_put_delayed_ref(ref);
2459                                 cond_resched();
2460                                 goto again;
2461                         }
2462                         node = rb_next(node);
2463                 }
2464                 spin_unlock(&delayed_refs->lock);
2465                 schedule_timeout(1);
2466                 goto again;
2467         }
2468 out:
2469         spin_unlock(&delayed_refs->lock);
2470         return 0;
2471 }
2472
2473 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2474                                 struct btrfs_root *root,
2475                                 u64 bytenr, u64 num_bytes, u64 flags,
2476                                 int is_data)
2477 {
2478         struct btrfs_delayed_extent_op *extent_op;
2479         int ret;
2480
2481         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2482         if (!extent_op)
2483                 return -ENOMEM;
2484
2485         extent_op->flags_to_set = flags;
2486         extent_op->update_flags = 1;
2487         extent_op->update_key = 0;
2488         extent_op->is_data = is_data ? 1 : 0;
2489
2490         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2491                                           num_bytes, extent_op);
2492         if (ret)
2493                 kfree(extent_op);
2494         return ret;
2495 }
2496
2497 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2498                                       struct btrfs_root *root,
2499                                       struct btrfs_path *path,
2500                                       u64 objectid, u64 offset, u64 bytenr)
2501 {
2502         struct btrfs_delayed_ref_head *head;
2503         struct btrfs_delayed_ref_node *ref;
2504         struct btrfs_delayed_data_ref *data_ref;
2505         struct btrfs_delayed_ref_root *delayed_refs;
2506         struct rb_node *node;
2507         int ret = 0;
2508
2509         ret = -ENOENT;
2510         delayed_refs = &trans->transaction->delayed_refs;
2511         spin_lock(&delayed_refs->lock);
2512         head = btrfs_find_delayed_ref_head(trans, bytenr);
2513         if (!head)
2514                 goto out;
2515
2516         if (!mutex_trylock(&head->mutex)) {
2517                 atomic_inc(&head->node.refs);
2518                 spin_unlock(&delayed_refs->lock);
2519
2520                 btrfs_release_path(path);
2521
2522                 /*
2523                  * Mutex was contended, block until it's released and let
2524                  * caller try again
2525                  */
2526                 mutex_lock(&head->mutex);
2527                 mutex_unlock(&head->mutex);
2528                 btrfs_put_delayed_ref(&head->node);
2529                 return -EAGAIN;
2530         }
2531
2532         node = rb_prev(&head->node.rb_node);
2533         if (!node)
2534                 goto out_unlock;
2535
2536         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2537
2538         if (ref->bytenr != bytenr)
2539                 goto out_unlock;
2540
2541         ret = 1;
2542         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2543                 goto out_unlock;
2544
2545         data_ref = btrfs_delayed_node_to_data_ref(ref);
2546
2547         node = rb_prev(node);
2548         if (node) {
2549                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2550                 if (ref->bytenr == bytenr)
2551                         goto out_unlock;
2552         }
2553
2554         if (data_ref->root != root->root_key.objectid ||
2555             data_ref->objectid != objectid || data_ref->offset != offset)
2556                 goto out_unlock;
2557
2558         ret = 0;
2559 out_unlock:
2560         mutex_unlock(&head->mutex);
2561 out:
2562         spin_unlock(&delayed_refs->lock);
2563         return ret;
2564 }
2565
2566 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2567                                         struct btrfs_root *root,
2568                                         struct btrfs_path *path,
2569                                         u64 objectid, u64 offset, u64 bytenr)
2570 {
2571         struct btrfs_root *extent_root = root->fs_info->extent_root;
2572         struct extent_buffer *leaf;
2573         struct btrfs_extent_data_ref *ref;
2574         struct btrfs_extent_inline_ref *iref;
2575         struct btrfs_extent_item *ei;
2576         struct btrfs_key key;
2577         u32 item_size;
2578         int ret;
2579
2580         key.objectid = bytenr;
2581         key.offset = (u64)-1;
2582         key.type = BTRFS_EXTENT_ITEM_KEY;
2583
2584         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2585         if (ret < 0)
2586                 goto out;
2587         BUG_ON(ret == 0);
2588
2589         ret = -ENOENT;
2590         if (path->slots[0] == 0)
2591                 goto out;
2592
2593         path->slots[0]--;
2594         leaf = path->nodes[0];
2595         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2596
2597         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2598                 goto out;
2599
2600         ret = 1;
2601         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2602 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2603         if (item_size < sizeof(*ei)) {
2604                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2605                 goto out;
2606         }
2607 #endif
2608         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2609
2610         if (item_size != sizeof(*ei) +
2611             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2612                 goto out;
2613
2614         if (btrfs_extent_generation(leaf, ei) <=
2615             btrfs_root_last_snapshot(&root->root_item))
2616                 goto out;
2617
2618         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2619         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2620             BTRFS_EXTENT_DATA_REF_KEY)
2621                 goto out;
2622
2623         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2624         if (btrfs_extent_refs(leaf, ei) !=
2625             btrfs_extent_data_ref_count(leaf, ref) ||
2626             btrfs_extent_data_ref_root(leaf, ref) !=
2627             root->root_key.objectid ||
2628             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2629             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2630                 goto out;
2631
2632         ret = 0;
2633 out:
2634         return ret;
2635 }
2636
2637 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2638                           struct btrfs_root *root,
2639                           u64 objectid, u64 offset, u64 bytenr)
2640 {
2641         struct btrfs_path *path;
2642         int ret;
2643         int ret2;
2644
2645         path = btrfs_alloc_path();
2646         if (!path)
2647                 return -ENOENT;
2648
2649         do {
2650                 ret = check_committed_ref(trans, root, path, objectid,
2651                                           offset, bytenr);
2652                 if (ret && ret != -ENOENT)
2653                         goto out;
2654
2655                 ret2 = check_delayed_ref(trans, root, path, objectid,
2656                                          offset, bytenr);
2657         } while (ret2 == -EAGAIN);
2658
2659         if (ret2 && ret2 != -ENOENT) {
2660                 ret = ret2;
2661                 goto out;
2662         }
2663
2664         if (ret != -ENOENT || ret2 != -ENOENT)
2665                 ret = 0;
2666 out:
2667         btrfs_free_path(path);
2668         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2669                 WARN_ON(ret > 0);
2670         return ret;
2671 }
2672
2673 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2674                            struct btrfs_root *root,
2675                            struct extent_buffer *buf,
2676                            int full_backref, int inc, int for_cow)
2677 {
2678         u64 bytenr;
2679         u64 num_bytes;
2680         u64 parent;
2681         u64 ref_root;
2682         u32 nritems;
2683         struct btrfs_key key;
2684         struct btrfs_file_extent_item *fi;
2685         int i;
2686         int level;
2687         int ret = 0;
2688         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2689                             u64, u64, u64, u64, u64, u64, int);
2690
2691         ref_root = btrfs_header_owner(buf);
2692         nritems = btrfs_header_nritems(buf);
2693         level = btrfs_header_level(buf);
2694
2695         if (!root->ref_cows && level == 0)
2696                 return 0;
2697
2698         if (inc)
2699                 process_func = btrfs_inc_extent_ref;
2700         else
2701                 process_func = btrfs_free_extent;
2702
2703         if (full_backref)
2704                 parent = buf->start;
2705         else
2706                 parent = 0;
2707
2708         for (i = 0; i < nritems; i++) {
2709                 if (level == 0) {
2710                         btrfs_item_key_to_cpu(buf, &key, i);
2711                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2712                                 continue;
2713                         fi = btrfs_item_ptr(buf, i,
2714                                             struct btrfs_file_extent_item);
2715                         if (btrfs_file_extent_type(buf, fi) ==
2716                             BTRFS_FILE_EXTENT_INLINE)
2717                                 continue;
2718                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2719                         if (bytenr == 0)
2720                                 continue;
2721
2722                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2723                         key.offset -= btrfs_file_extent_offset(buf, fi);
2724                         ret = process_func(trans, root, bytenr, num_bytes,
2725                                            parent, ref_root, key.objectid,
2726                                            key.offset, for_cow);
2727                         if (ret)
2728                                 goto fail;
2729                 } else {
2730                         bytenr = btrfs_node_blockptr(buf, i);
2731                         num_bytes = btrfs_level_size(root, level - 1);
2732                         ret = process_func(trans, root, bytenr, num_bytes,
2733                                            parent, ref_root, level - 1, 0,
2734                                            for_cow);
2735                         if (ret)
2736                                 goto fail;
2737                 }
2738         }
2739         return 0;
2740 fail:
2741         BUG();
2742         return ret;
2743 }
2744
2745 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2746                   struct extent_buffer *buf, int full_backref, int for_cow)
2747 {
2748         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
2749 }
2750
2751 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2752                   struct extent_buffer *buf, int full_backref, int for_cow)
2753 {
2754         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
2755 }
2756
2757 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2758                                  struct btrfs_root *root,
2759                                  struct btrfs_path *path,
2760                                  struct btrfs_block_group_cache *cache)
2761 {
2762         int ret;
2763         struct btrfs_root *extent_root = root->fs_info->extent_root;
2764         unsigned long bi;
2765         struct extent_buffer *leaf;
2766
2767         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2768         if (ret < 0)
2769                 goto fail;
2770         BUG_ON(ret);
2771
2772         leaf = path->nodes[0];
2773         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2774         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2775         btrfs_mark_buffer_dirty(leaf);
2776         btrfs_release_path(path);
2777 fail:
2778         if (ret)
2779                 return ret;
2780         return 0;
2781
2782 }
2783
2784 static struct btrfs_block_group_cache *
2785 next_block_group(struct btrfs_root *root,
2786                  struct btrfs_block_group_cache *cache)
2787 {
2788         struct rb_node *node;
2789         spin_lock(&root->fs_info->block_group_cache_lock);
2790         node = rb_next(&cache->cache_node);
2791         btrfs_put_block_group(cache);
2792         if (node) {
2793                 cache = rb_entry(node, struct btrfs_block_group_cache,
2794                                  cache_node);
2795                 btrfs_get_block_group(cache);
2796         } else
2797                 cache = NULL;
2798         spin_unlock(&root->fs_info->block_group_cache_lock);
2799         return cache;
2800 }
2801
2802 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2803                             struct btrfs_trans_handle *trans,
2804                             struct btrfs_path *path)
2805 {
2806         struct btrfs_root *root = block_group->fs_info->tree_root;
2807         struct inode *inode = NULL;
2808         u64 alloc_hint = 0;
2809         int dcs = BTRFS_DC_ERROR;
2810         int num_pages = 0;
2811         int retries = 0;
2812         int ret = 0;
2813
2814         /*
2815          * If this block group is smaller than 100 megs don't bother caching the
2816          * block group.
2817          */
2818         if (block_group->key.offset < (100 * 1024 * 1024)) {
2819                 spin_lock(&block_group->lock);
2820                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2821                 spin_unlock(&block_group->lock);
2822                 return 0;
2823         }
2824
2825 again:
2826         inode = lookup_free_space_inode(root, block_group, path);
2827         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2828                 ret = PTR_ERR(inode);
2829                 btrfs_release_path(path);
2830                 goto out;
2831         }
2832
2833         if (IS_ERR(inode)) {
2834                 BUG_ON(retries);
2835                 retries++;
2836
2837                 if (block_group->ro)
2838                         goto out_free;
2839
2840                 ret = create_free_space_inode(root, trans, block_group, path);
2841                 if (ret)
2842                         goto out_free;
2843                 goto again;
2844         }
2845
2846         /* We've already setup this transaction, go ahead and exit */
2847         if (block_group->cache_generation == trans->transid &&
2848             i_size_read(inode)) {
2849                 dcs = BTRFS_DC_SETUP;
2850                 goto out_put;
2851         }
2852
2853         /*
2854          * We want to set the generation to 0, that way if anything goes wrong
2855          * from here on out we know not to trust this cache when we load up next
2856          * time.
2857          */
2858         BTRFS_I(inode)->generation = 0;
2859         ret = btrfs_update_inode(trans, root, inode);
2860         WARN_ON(ret);
2861
2862         if (i_size_read(inode) > 0) {
2863                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2864                                                       inode);
2865                 if (ret)
2866                         goto out_put;
2867         }
2868
2869         spin_lock(&block_group->lock);
2870         if (block_group->cached != BTRFS_CACHE_FINISHED) {
2871                 /* We're not cached, don't bother trying to write stuff out */
2872                 dcs = BTRFS_DC_WRITTEN;
2873                 spin_unlock(&block_group->lock);
2874                 goto out_put;
2875         }
2876         spin_unlock(&block_group->lock);
2877
2878         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2879         if (!num_pages)
2880                 num_pages = 1;
2881
2882         /*
2883          * Just to make absolutely sure we have enough space, we're going to
2884          * preallocate 12 pages worth of space for each block group.  In
2885          * practice we ought to use at most 8, but we need extra space so we can
2886          * add our header and have a terminator between the extents and the
2887          * bitmaps.
2888          */
2889         num_pages *= 16;
2890         num_pages *= PAGE_CACHE_SIZE;
2891
2892         ret = btrfs_check_data_free_space(inode, num_pages);
2893         if (ret)
2894                 goto out_put;
2895
2896         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2897                                               num_pages, num_pages,
2898                                               &alloc_hint);
2899         if (!ret)
2900                 dcs = BTRFS_DC_SETUP;
2901         btrfs_free_reserved_data_space(inode, num_pages);
2902
2903 out_put:
2904         iput(inode);
2905 out_free:
2906         btrfs_release_path(path);
2907 out:
2908         spin_lock(&block_group->lock);
2909         if (!ret && dcs == BTRFS_DC_SETUP)
2910                 block_group->cache_generation = trans->transid;
2911         block_group->disk_cache_state = dcs;
2912         spin_unlock(&block_group->lock);
2913
2914         return ret;
2915 }
2916
2917 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2918                                    struct btrfs_root *root)
2919 {
2920         struct btrfs_block_group_cache *cache;
2921         int err = 0;
2922         struct btrfs_path *path;
2923         u64 last = 0;
2924
2925         path = btrfs_alloc_path();
2926         if (!path)
2927                 return -ENOMEM;
2928
2929 again:
2930         while (1) {
2931                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2932                 while (cache) {
2933                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2934                                 break;
2935                         cache = next_block_group(root, cache);
2936                 }
2937                 if (!cache) {
2938                         if (last == 0)
2939                                 break;
2940                         last = 0;
2941                         continue;
2942                 }
2943                 err = cache_save_setup(cache, trans, path);
2944                 last = cache->key.objectid + cache->key.offset;
2945                 btrfs_put_block_group(cache);
2946         }
2947
2948         while (1) {
2949                 if (last == 0) {
2950                         err = btrfs_run_delayed_refs(trans, root,
2951                                                      (unsigned long)-1);
2952                         BUG_ON(err);
2953                 }
2954
2955                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2956                 while (cache) {
2957                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
2958                                 btrfs_put_block_group(cache);
2959                                 goto again;
2960                         }
2961
2962                         if (cache->dirty)
2963                                 break;
2964                         cache = next_block_group(root, cache);
2965                 }
2966                 if (!cache) {
2967                         if (last == 0)
2968                                 break;
2969                         last = 0;
2970                         continue;
2971                 }
2972
2973                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
2974                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
2975                 cache->dirty = 0;
2976                 last = cache->key.objectid + cache->key.offset;
2977
2978                 err = write_one_cache_group(trans, root, path, cache);
2979                 BUG_ON(err);
2980                 btrfs_put_block_group(cache);
2981         }
2982
2983         while (1) {
2984                 /*
2985                  * I don't think this is needed since we're just marking our
2986                  * preallocated extent as written, but just in case it can't
2987                  * hurt.
2988                  */
2989                 if (last == 0) {
2990                         err = btrfs_run_delayed_refs(trans, root,
2991                                                      (unsigned long)-1);
2992                         BUG_ON(err);
2993                 }
2994
2995                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2996                 while (cache) {
2997                         /*
2998                          * Really this shouldn't happen, but it could if we
2999                          * couldn't write the entire preallocated extent and
3000                          * splitting the extent resulted in a new block.
3001                          */
3002                         if (cache->dirty) {
3003                                 btrfs_put_block_group(cache);
3004                                 goto again;
3005                         }
3006                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3007                                 break;
3008                         cache = next_block_group(root, cache);
3009                 }
3010                 if (!cache) {
3011                         if (last == 0)
3012                                 break;
3013                         last = 0;
3014                         continue;
3015                 }
3016
3017                 btrfs_write_out_cache(root, trans, cache, path);
3018
3019                 /*
3020                  * If we didn't have an error then the cache state is still
3021                  * NEED_WRITE, so we can set it to WRITTEN.
3022                  */
3023                 if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3024                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3025                 last = cache->key.objectid + cache->key.offset;
3026                 btrfs_put_block_group(cache);
3027         }
3028
3029         btrfs_free_path(path);
3030         return 0;
3031 }
3032
3033 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3034 {
3035         struct btrfs_block_group_cache *block_group;
3036         int readonly = 0;
3037
3038         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3039         if (!block_group || block_group->ro)
3040                 readonly = 1;
3041         if (block_group)
3042                 btrfs_put_block_group(block_group);
3043         return readonly;
3044 }
3045
3046 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3047                              u64 total_bytes, u64 bytes_used,
3048                              struct btrfs_space_info **space_info)
3049 {
3050         struct btrfs_space_info *found;
3051         int i;
3052         int factor;
3053
3054         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3055                      BTRFS_BLOCK_GROUP_RAID10))
3056                 factor = 2;
3057         else
3058                 factor = 1;
3059
3060         found = __find_space_info(info, flags);
3061         if (found) {
3062                 spin_lock(&found->lock);
3063                 found->total_bytes += total_bytes;
3064                 found->disk_total += total_bytes * factor;
3065                 found->bytes_used += bytes_used;
3066                 found->disk_used += bytes_used * factor;
3067                 found->full = 0;
3068                 spin_unlock(&found->lock);
3069                 *space_info = found;
3070                 return 0;
3071         }
3072         found = kzalloc(sizeof(*found), GFP_NOFS);
3073         if (!found)
3074                 return -ENOMEM;
3075
3076         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3077                 INIT_LIST_HEAD(&found->block_groups[i]);
3078         init_rwsem(&found->groups_sem);
3079         spin_lock_init(&found->lock);
3080         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3081         found->total_bytes = total_bytes;
3082         found->disk_total = total_bytes * factor;
3083         found->bytes_used = bytes_used;
3084         found->disk_used = bytes_used * factor;
3085         found->bytes_pinned = 0;
3086         found->bytes_reserved = 0;
3087         found->bytes_readonly = 0;
3088         found->bytes_may_use = 0;
3089         found->full = 0;
3090         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3091         found->chunk_alloc = 0;
3092         found->flush = 0;
3093         init_waitqueue_head(&found->wait);
3094         *space_info = found;
3095         list_add_rcu(&found->list, &info->space_info);
3096         return 0;
3097 }
3098
3099 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3100 {
3101         u64 extra_flags = flags & BTRFS_BLOCK_GROUP_PROFILE_MASK;
3102
3103         /* chunk -> extended profile */
3104         if (extra_flags == 0)
3105                 extra_flags = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3106
3107         if (flags & BTRFS_BLOCK_GROUP_DATA)
3108                 fs_info->avail_data_alloc_bits |= extra_flags;
3109         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3110                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3111         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3112                 fs_info->avail_system_alloc_bits |= extra_flags;
3113 }
3114
3115 /*
3116  * @flags: available profiles in extended format (see ctree.h)
3117  *
3118  * Returns reduced profile in chunk format.  If profile changing is in
3119  * progress (either running or paused) picks the target profile (if it's
3120  * already available), otherwise falls back to plain reducing.
3121  */
3122 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3123 {
3124         /*
3125          * we add in the count of missing devices because we want
3126          * to make sure that any RAID levels on a degraded FS
3127          * continue to be honored.
3128          */
3129         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3130                 root->fs_info->fs_devices->missing_devices;
3131
3132         /* pick restriper's target profile if it's available */
3133         spin_lock(&root->fs_info->balance_lock);
3134         if (root->fs_info->balance_ctl) {
3135                 struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
3136                 u64 tgt = 0;
3137
3138                 if ((flags & BTRFS_BLOCK_GROUP_DATA) &&
3139                     (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3140                     (flags & bctl->data.target)) {
3141                         tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3142                 } else if ((flags & BTRFS_BLOCK_GROUP_SYSTEM) &&
3143                            (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3144                            (flags & bctl->sys.target)) {
3145                         tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3146                 } else if ((flags & BTRFS_BLOCK_GROUP_METADATA) &&
3147                            (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3148                            (flags & bctl->meta.target)) {
3149                         tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3150                 }
3151
3152                 if (tgt) {
3153                         spin_unlock(&root->fs_info->balance_lock);
3154                         flags = tgt;
3155                         goto out;
3156                 }
3157         }
3158         spin_unlock(&root->fs_info->balance_lock);
3159
3160         if (num_devices == 1)
3161                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
3162         if (num_devices < 4)
3163                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3164
3165         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
3166             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3167                       BTRFS_BLOCK_GROUP_RAID10))) {
3168                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
3169         }
3170
3171         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
3172             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
3173                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
3174         }
3175
3176         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
3177             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
3178              (flags & BTRFS_BLOCK_GROUP_RAID10) |
3179              (flags & BTRFS_BLOCK_GROUP_DUP))) {
3180                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
3181         }
3182
3183 out:
3184         /* extended -> chunk profile */
3185         flags &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3186         return flags;
3187 }
3188
3189 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3190 {
3191         if (flags & BTRFS_BLOCK_GROUP_DATA)
3192                 flags |= root->fs_info->avail_data_alloc_bits;
3193         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3194                 flags |= root->fs_info->avail_system_alloc_bits;
3195         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3196                 flags |= root->fs_info->avail_metadata_alloc_bits;
3197
3198         return btrfs_reduce_alloc_profile(root, flags);
3199 }
3200
3201 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3202 {
3203         u64 flags;
3204
3205         if (data)
3206                 flags = BTRFS_BLOCK_GROUP_DATA;
3207         else if (root == root->fs_info->chunk_root)
3208                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3209         else
3210                 flags = BTRFS_BLOCK_GROUP_METADATA;
3211
3212         return get_alloc_profile(root, flags);
3213 }
3214
3215 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
3216 {
3217         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
3218                                                        BTRFS_BLOCK_GROUP_DATA);
3219 }
3220
3221 /*
3222  * This will check the space that the inode allocates from to make sure we have
3223  * enough space for bytes.
3224  */
3225 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3226 {
3227         struct btrfs_space_info *data_sinfo;
3228         struct btrfs_root *root = BTRFS_I(inode)->root;
3229         u64 used;
3230         int ret = 0, committed = 0, alloc_chunk = 1;
3231
3232         /* make sure bytes are sectorsize aligned */
3233         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3234
3235         if (root == root->fs_info->tree_root ||
3236             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3237                 alloc_chunk = 0;
3238                 committed = 1;
3239         }
3240
3241         data_sinfo = BTRFS_I(inode)->space_info;
3242         if (!data_sinfo)
3243                 goto alloc;
3244
3245 again:
3246         /* make sure we have enough space to handle the data first */
3247         spin_lock(&data_sinfo->lock);
3248         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3249                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3250                 data_sinfo->bytes_may_use;
3251
3252         if (used + bytes > data_sinfo->total_bytes) {
3253                 struct btrfs_trans_handle *trans;
3254
3255                 /*
3256                  * if we don't have enough free bytes in this space then we need
3257                  * to alloc a new chunk.
3258                  */
3259                 if (!data_sinfo->full && alloc_chunk) {
3260                         u64 alloc_target;
3261
3262                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3263                         spin_unlock(&data_sinfo->lock);
3264 alloc:
3265                         alloc_target = btrfs_get_alloc_profile(root, 1);
3266                         trans = btrfs_join_transaction(root);
3267                         if (IS_ERR(trans))
3268                                 return PTR_ERR(trans);
3269
3270                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3271                                              bytes + 2 * 1024 * 1024,
3272                                              alloc_target,
3273                                              CHUNK_ALLOC_NO_FORCE);
3274                         btrfs_end_transaction(trans, root);
3275                         if (ret < 0) {
3276                                 if (ret != -ENOSPC)
3277                                         return ret;
3278                                 else
3279                                         goto commit_trans;
3280                         }
3281
3282                         if (!data_sinfo) {
3283                                 btrfs_set_inode_space_info(root, inode);
3284                                 data_sinfo = BTRFS_I(inode)->space_info;
3285                         }
3286                         goto again;
3287                 }
3288
3289                 /*
3290                  * If we have less pinned bytes than we want to allocate then
3291                  * don't bother committing the transaction, it won't help us.
3292                  */
3293                 if (data_sinfo->bytes_pinned < bytes)
3294                         committed = 1;
3295                 spin_unlock(&data_sinfo->lock);
3296
3297                 /* commit the current transaction and try again */
3298 commit_trans:
3299                 if (!committed &&
3300                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3301                         committed = 1;
3302                         trans = btrfs_join_transaction(root);
3303                         if (IS_ERR(trans))
3304                                 return PTR_ERR(trans);
3305                         ret = btrfs_commit_transaction(trans, root);
3306                         if (ret)
3307                                 return ret;
3308                         goto again;
3309                 }
3310
3311                 return -ENOSPC;
3312         }
3313         data_sinfo->bytes_may_use += bytes;
3314         trace_btrfs_space_reservation(root->fs_info, "space_info",
3315                                       (u64)(unsigned long)data_sinfo,
3316                                       bytes, 1);
3317         spin_unlock(&data_sinfo->lock);
3318
3319         return 0;
3320 }
3321
3322 /*
3323  * Called if we need to clear a data reservation for this inode.
3324  */
3325 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3326 {
3327         struct btrfs_root *root = BTRFS_I(inode)->root;
3328         struct btrfs_space_info *data_sinfo;
3329
3330         /* make sure bytes are sectorsize aligned */
3331         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3332
3333         data_sinfo = BTRFS_I(inode)->space_info;
3334         spin_lock(&data_sinfo->lock);
3335         data_sinfo->bytes_may_use -= bytes;
3336         trace_btrfs_space_reservation(root->fs_info, "space_info",
3337                                       (u64)(unsigned long)data_sinfo,
3338                                       bytes, 0);
3339         spin_unlock(&data_sinfo->lock);
3340 }
3341
3342 static void force_metadata_allocation(struct btrfs_fs_info *info)
3343 {
3344         struct list_head *head = &info->space_info;
3345         struct btrfs_space_info *found;
3346
3347         rcu_read_lock();
3348         list_for_each_entry_rcu(found, head, list) {
3349                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3350                         found->force_alloc = CHUNK_ALLOC_FORCE;
3351         }
3352         rcu_read_unlock();
3353 }
3354
3355 static int should_alloc_chunk(struct btrfs_root *root,
3356                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3357                               int force)
3358 {
3359         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3360         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3361         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3362         u64 thresh;
3363
3364         if (force == CHUNK_ALLOC_FORCE)
3365                 return 1;
3366
3367         /*
3368          * We need to take into account the global rsv because for all intents
3369          * and purposes it's used space.  Don't worry about locking the
3370          * global_rsv, it doesn't change except when the transaction commits.
3371          */
3372         num_allocated += global_rsv->size;
3373
3374         /*
3375          * in limited mode, we want to have some free space up to
3376          * about 1% of the FS size.
3377          */
3378         if (force == CHUNK_ALLOC_LIMITED) {
3379                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3380                 thresh = max_t(u64, 64 * 1024 * 1024,
3381                                div_factor_fine(thresh, 1));
3382
3383                 if (num_bytes - num_allocated < thresh)
3384                         return 1;
3385         }
3386         thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3387
3388         /* 256MB or 2% of the FS */
3389         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 2));
3390         /* system chunks need a much small threshold */
3391         if (sinfo->flags & BTRFS_BLOCK_GROUP_SYSTEM)
3392                 thresh = 32 * 1024 * 1024;
3393
3394         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 8))
3395                 return 0;
3396         return 1;
3397 }
3398
3399 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3400                           struct btrfs_root *extent_root, u64 alloc_bytes,
3401                           u64 flags, int force)
3402 {
3403         struct btrfs_space_info *space_info;
3404         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3405         int wait_for_alloc = 0;
3406         int ret = 0;
3407
3408         BUG_ON(!profile_is_valid(flags, 0));
3409
3410         space_info = __find_space_info(extent_root->fs_info, flags);
3411         if (!space_info) {
3412                 ret = update_space_info(extent_root->fs_info, flags,
3413                                         0, 0, &space_info);
3414                 BUG_ON(ret);
3415         }
3416         BUG_ON(!space_info);
3417
3418 again:
3419         spin_lock(&space_info->lock);
3420         if (force < space_info->force_alloc)
3421                 force = space_info->force_alloc;
3422         if (space_info->full) {
3423                 spin_unlock(&space_info->lock);
3424                 return 0;
3425         }
3426
3427         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3428                 spin_unlock(&space_info->lock);
3429                 return 0;
3430         } else if (space_info->chunk_alloc) {
3431                 wait_for_alloc = 1;
3432         } else {
3433                 space_info->chunk_alloc = 1;
3434         }
3435
3436         spin_unlock(&space_info->lock);
3437
3438         mutex_lock(&fs_info->chunk_mutex);
3439
3440         /*
3441          * The chunk_mutex is held throughout the entirety of a chunk
3442          * allocation, so once we've acquired the chunk_mutex we know that the
3443          * other guy is done and we need to recheck and see if we should
3444          * allocate.
3445          */
3446         if (wait_for_alloc) {
3447                 mutex_unlock(&fs_info->chunk_mutex);
3448                 wait_for_alloc = 0;
3449                 goto again;
3450         }
3451
3452         /*
3453          * If we have mixed data/metadata chunks we want to make sure we keep
3454          * allocating mixed chunks instead of individual chunks.
3455          */
3456         if (btrfs_mixed_space_info(space_info))
3457                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3458
3459         /*
3460          * if we're doing a data chunk, go ahead and make sure that
3461          * we keep a reasonable number of metadata chunks allocated in the
3462          * FS as well.
3463          */
3464         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3465                 fs_info->data_chunk_allocations++;
3466                 if (!(fs_info->data_chunk_allocations %
3467                       fs_info->metadata_ratio))
3468                         force_metadata_allocation(fs_info);
3469         }
3470
3471         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3472         if (ret < 0 && ret != -ENOSPC)
3473                 goto out;
3474
3475         spin_lock(&space_info->lock);
3476         if (ret)
3477                 space_info->full = 1;
3478         else
3479                 ret = 1;
3480
3481         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3482         space_info->chunk_alloc = 0;
3483         spin_unlock(&space_info->lock);
3484 out:
3485         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3486         return ret;
3487 }
3488
3489 /*
3490  * shrink metadata reservation for delalloc
3491  */
3492 static int shrink_delalloc(struct btrfs_root *root, u64 to_reclaim,
3493                            bool wait_ordered)
3494 {
3495         struct btrfs_block_rsv *block_rsv;
3496         struct btrfs_space_info *space_info;
3497         struct btrfs_trans_handle *trans;
3498         u64 reserved;
3499         u64 max_reclaim;
3500         u64 reclaimed = 0;
3501         long time_left;
3502         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3503         int loops = 0;
3504         unsigned long progress;
3505
3506         trans = (struct btrfs_trans_handle *)current->journal_info;
3507         block_rsv = &root->fs_info->delalloc_block_rsv;
3508         space_info = block_rsv->space_info;
3509
3510         smp_mb();
3511         reserved = space_info->bytes_may_use;
3512         progress = space_info->reservation_progress;
3513
3514         if (reserved == 0)
3515                 return 0;
3516
3517         smp_mb();
3518         if (root->fs_info->delalloc_bytes == 0) {
3519                 if (trans)
3520                         return 0;
3521                 btrfs_wait_ordered_extents(root, 0, 0);
3522                 return 0;
3523         }
3524
3525         max_reclaim = min(reserved, to_reclaim);
3526         nr_pages = max_t(unsigned long, nr_pages,
3527                          max_reclaim >> PAGE_CACHE_SHIFT);
3528         while (loops < 1024) {
3529                 /* have the flusher threads jump in and do some IO */
3530                 smp_mb();
3531                 nr_pages = min_t(unsigned long, nr_pages,
3532                        root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
3533                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages,
3534                                                 WB_REASON_FS_FREE_SPACE);
3535
3536                 spin_lock(&space_info->lock);
3537                 if (reserved > space_info->bytes_may_use)
3538                         reclaimed += reserved - space_info->bytes_may_use;
3539                 reserved = space_info->bytes_may_use;
3540                 spin_unlock(&space_info->lock);
3541
3542                 loops++;
3543
3544                 if (reserved == 0 || reclaimed >= max_reclaim)
3545                         break;
3546
3547                 if (trans && trans->transaction->blocked)
3548                         return -EAGAIN;
3549
3550                 if (wait_ordered && !trans) {
3551                         btrfs_wait_ordered_extents(root, 0, 0);
3552                 } else {
3553                         time_left = schedule_timeout_interruptible(1);
3554
3555                         /* We were interrupted, exit */
3556                         if (time_left)
3557                                 break;
3558                 }
3559
3560                 /* we've kicked the IO a few times, if anything has been freed,
3561                  * exit.  There is no sense in looping here for a long time
3562                  * when we really need to commit the transaction, or there are
3563                  * just too many writers without enough free space
3564                  */
3565
3566                 if (loops > 3) {
3567                         smp_mb();
3568                         if (progress != space_info->reservation_progress)
3569                                 break;
3570                 }
3571
3572         }
3573
3574         return reclaimed >= to_reclaim;
3575 }
3576
3577 /**
3578  * maybe_commit_transaction - possibly commit the transaction if its ok to
3579  * @root - the root we're allocating for
3580  * @bytes - the number of bytes we want to reserve
3581  * @force - force the commit
3582  *
3583  * This will check to make sure that committing the transaction will actually
3584  * get us somewhere and then commit the transaction if it does.  Otherwise it
3585  * will return -ENOSPC.
3586  */
3587 static int may_commit_transaction(struct btrfs_root *root,
3588                                   struct btrfs_space_info *space_info,
3589                                   u64 bytes, int force)
3590 {
3591         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
3592         struct btrfs_trans_handle *trans;
3593
3594         trans = (struct btrfs_trans_handle *)current->journal_info;
3595         if (trans)
3596                 return -EAGAIN;
3597
3598         if (force)
3599                 goto commit;
3600
3601         /* See if there is enough pinned space to make this reservation */
3602         spin_lock(&space_info->lock);
3603         if (space_info->bytes_pinned >= bytes) {
3604                 spin_unlock(&space_info->lock);
3605                 goto commit;
3606         }
3607         spin_unlock(&space_info->lock);
3608
3609         /*
3610          * See if there is some space in the delayed insertion reservation for
3611          * this reservation.
3612          */
3613         if (space_info != delayed_rsv->space_info)
3614                 return -ENOSPC;
3615
3616         spin_lock(&space_info->lock);
3617         spin_lock(&delayed_rsv->lock);
3618         if (space_info->bytes_pinned + delayed_rsv->size < bytes) {
3619                 spin_unlock(&delayed_rsv->lock);
3620                 spin_unlock(&space_info->lock);
3621                 return -ENOSPC;
3622         }
3623         spin_unlock(&delayed_rsv->lock);
3624         spin_unlock(&space_info->lock);
3625
3626 commit:
3627         trans = btrfs_join_transaction(root);
3628         if (IS_ERR(trans))
3629                 return -ENOSPC;
3630
3631         return btrfs_commit_transaction(trans, root);
3632 }
3633
3634 /**
3635  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
3636  * @root - the root we're allocating for
3637  * @block_rsv - the block_rsv we're allocating for
3638  * @orig_bytes - the number of bytes we want
3639  * @flush - wether or not we can flush to make our reservation
3640  *
3641  * This will reserve orgi_bytes number of bytes from the space info associated
3642  * with the block_rsv.  If there is not enough space it will make an attempt to
3643  * flush out space to make room.  It will do this by flushing delalloc if
3644  * possible or committing the transaction.  If flush is 0 then no attempts to
3645  * regain reservations will be made and this will fail if there is not enough
3646  * space already.
3647  */
3648 static int reserve_metadata_bytes(struct btrfs_root *root,
3649                                   struct btrfs_block_rsv *block_rsv,
3650                                   u64 orig_bytes, int flush)
3651 {
3652         struct btrfs_space_info *space_info = block_rsv->space_info;
3653         u64 used;
3654         u64 num_bytes = orig_bytes;
3655         int retries = 0;
3656         int ret = 0;
3657         bool committed = false;
3658         bool flushing = false;
3659         bool wait_ordered = false;
3660
3661 again:
3662         ret = 0;
3663         spin_lock(&space_info->lock);
3664         /*
3665          * We only want to wait if somebody other than us is flushing and we are
3666          * actually alloed to flush.
3667          */
3668         while (flush && !flushing && space_info->flush) {
3669                 spin_unlock(&space_info->lock);
3670                 /*
3671                  * If we have a trans handle we can't wait because the flusher
3672                  * may have to commit the transaction, which would mean we would
3673                  * deadlock since we are waiting for the flusher to finish, but
3674                  * hold the current transaction open.
3675                  */
3676                 if (current->journal_info)
3677                         return -EAGAIN;
3678                 ret = wait_event_interruptible(space_info->wait,
3679                                                !space_info->flush);
3680                 /* Must have been interrupted, return */
3681                 if (ret)
3682                         return -EINTR;
3683
3684                 spin_lock(&space_info->lock);
3685         }
3686
3687         ret = -ENOSPC;
3688         used = space_info->bytes_used + space_info->bytes_reserved +
3689                 space_info->bytes_pinned + space_info->bytes_readonly +
3690                 space_info->bytes_may_use;
3691
3692         /*
3693          * The idea here is that we've not already over-reserved the block group
3694          * then we can go ahead and save our reservation first and then start
3695          * flushing if we need to.  Otherwise if we've already overcommitted
3696          * lets start flushing stuff first and then come back and try to make
3697          * our reservation.
3698          */
3699         if (used <= space_info->total_bytes) {
3700                 if (used + orig_bytes <= space_info->total_bytes) {
3701                         space_info->bytes_may_use += orig_bytes;
3702                         trace_btrfs_space_reservation(root->fs_info,
3703                                               "space_info",
3704                                               (u64)(unsigned long)space_info,
3705                                               orig_bytes, 1);
3706                         ret = 0;
3707                 } else {
3708                         /*
3709                          * Ok set num_bytes to orig_bytes since we aren't
3710                          * overocmmitted, this way we only try and reclaim what
3711                          * we need.
3712                          */
3713                         num_bytes = orig_bytes;
3714                 }
3715         } else {
3716                 /*
3717                  * Ok we're over committed, set num_bytes to the overcommitted
3718                  * amount plus the amount of bytes that we need for this
3719                  * reservation.
3720                  */
3721                 wait_ordered = true;
3722                 num_bytes = used - space_info->total_bytes +
3723                         (orig_bytes * (retries + 1));
3724         }
3725
3726         if (ret) {
3727                 u64 profile = btrfs_get_alloc_profile(root, 0);
3728                 u64 avail;
3729
3730                 /*
3731                  * If we have a lot of space that's pinned, don't bother doing
3732                  * the overcommit dance yet and just commit the transaction.
3733                  */
3734                 avail = (space_info->total_bytes - space_info->bytes_used) * 8;
3735                 do_div(avail, 10);
3736                 if (space_info->bytes_pinned >= avail && flush && !committed) {
3737                         space_info->flush = 1;
3738                         flushing = true;
3739                         spin_unlock(&space_info->lock);
3740                         ret = may_commit_transaction(root, space_info,
3741                                                      orig_bytes, 1);
3742                         if (ret)
3743                                 goto out;
3744                         committed = true;
3745                         goto again;
3746                 }
3747
3748                 spin_lock(&root->fs_info->free_chunk_lock);
3749                 avail = root->fs_info->free_chunk_space;
3750
3751                 /*
3752                  * If we have dup, raid1 or raid10 then only half of the free
3753                  * space is actually useable.
3754                  */
3755                 if (profile & (BTRFS_BLOCK_GROUP_DUP |
3756                                BTRFS_BLOCK_GROUP_RAID1 |
3757                                BTRFS_BLOCK_GROUP_RAID10))
3758                         avail >>= 1;
3759
3760                 /*
3761                  * If we aren't flushing don't let us overcommit too much, say
3762                  * 1/8th of the space.  If we can flush, let it overcommit up to
3763                  * 1/2 of the space.
3764                  */
3765                 if (flush)
3766                         avail >>= 3;
3767                 else
3768                         avail >>= 1;
3769                  spin_unlock(&root->fs_info->free_chunk_lock);
3770
3771                 if (used + num_bytes < space_info->total_bytes + avail) {
3772                         space_info->bytes_may_use += orig_bytes;
3773                         trace_btrfs_space_reservation(root->fs_info,
3774                                               "space_info",
3775                                               (u64)(unsigned long)space_info,
3776                                               orig_bytes, 1);
3777                         ret = 0;
3778                 } else {
3779                         wait_ordered = true;
3780                 }
3781         }
3782
3783         /*
3784          * Couldn't make our reservation, save our place so while we're trying
3785          * to reclaim space we can actually use it instead of somebody else
3786          * stealing it from us.
3787          */
3788         if (ret && flush) {
3789                 flushing = true;
3790                 space_info->flush = 1;
3791         }
3792
3793         spin_unlock(&space_info->lock);
3794
3795         if (!ret || !flush)
3796                 goto out;
3797
3798         /*
3799          * We do synchronous shrinking since we don't actually unreserve
3800          * metadata until after the IO is completed.
3801          */
3802         ret = shrink_delalloc(root, num_bytes, wait_ordered);
3803         if (ret < 0)
3804                 goto out;
3805
3806         ret = 0;
3807
3808         /*
3809          * So if we were overcommitted it's possible that somebody else flushed
3810          * out enough space and we simply didn't have enough space to reclaim,
3811          * so go back around and try again.
3812          */
3813         if (retries < 2) {
3814                 wait_ordered = true;
3815                 retries++;
3816                 goto again;
3817         }
3818
3819         ret = -ENOSPC;
3820         if (committed)
3821                 goto out;
3822
3823         ret = may_commit_transaction(root, space_info, orig_bytes, 0);
3824         if (!ret) {
3825                 committed = true;
3826                 goto again;
3827         }
3828
3829 out:
3830         if (flushing) {
3831                 spin_lock(&space_info->lock);
3832                 space_info->flush = 0;
3833                 wake_up_all(&space_info->wait);
3834                 spin_unlock(&space_info->lock);
3835         }
3836         return ret;
3837 }
3838
3839 static struct btrfs_block_rsv *get_block_rsv(struct btrfs_trans_handle *trans,
3840                                              struct btrfs_root *root)
3841 {
3842         struct btrfs_block_rsv *block_rsv = NULL;
3843
3844         if (root->ref_cows || root == root->fs_info->csum_root)
3845                 block_rsv = trans->block_rsv;
3846
3847         if (!block_rsv)
3848                 block_rsv = root->block_rsv;
3849
3850         if (!block_rsv)
3851                 block_rsv = &root->fs_info->empty_block_rsv;
3852
3853         return block_rsv;
3854 }
3855
3856 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
3857                                u64 num_bytes)
3858 {
3859         int ret = -ENOSPC;
3860         spin_lock(&block_rsv->lock);
3861         if (block_rsv->reserved >= num_bytes) {
3862                 block_rsv->reserved -= num_bytes;
3863                 if (block_rsv->reserved < block_rsv->size)
3864                         block_rsv->full = 0;
3865                 ret = 0;
3866         }
3867         spin_unlock(&block_rsv->lock);
3868         return ret;
3869 }
3870
3871 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
3872                                 u64 num_bytes, int update_size)
3873 {
3874         spin_lock(&block_rsv->lock);
3875         block_rsv->reserved += num_bytes;
3876         if (update_size)
3877                 block_rsv->size += num_bytes;
3878         else if (block_rsv->reserved >= block_rsv->size)
3879                 block_rsv->full = 1;
3880         spin_unlock(&block_rsv->lock);
3881 }
3882
3883 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
3884                                     struct btrfs_block_rsv *block_rsv,
3885                                     struct btrfs_block_rsv *dest, u64 num_bytes)
3886 {
3887         struct btrfs_space_info *space_info = block_rsv->space_info;
3888
3889         spin_lock(&block_rsv->lock);
3890         if (num_bytes == (u64)-1)
3891                 num_bytes = block_rsv->size;
3892         block_rsv->size -= num_bytes;
3893         if (block_rsv->reserved >= block_rsv->size) {
3894                 num_bytes = block_rsv->reserved - block_rsv->size;
3895                 block_rsv->reserved = block_rsv->size;
3896                 block_rsv->full = 1;
3897         } else {
3898                 num_bytes = 0;
3899         }
3900         spin_unlock(&block_rsv->lock);
3901
3902         if (num_bytes > 0) {
3903                 if (dest) {
3904                         spin_lock(&dest->lock);
3905                         if (!dest->full) {
3906                                 u64 bytes_to_add;
3907
3908                                 bytes_to_add = dest->size - dest->reserved;
3909                                 bytes_to_add = min(num_bytes, bytes_to_add);
3910                                 dest->reserved += bytes_to_add;
3911                                 if (dest->reserved >= dest->size)
3912                                         dest->full = 1;
3913                                 num_bytes -= bytes_to_add;
3914                         }
3915                         spin_unlock(&dest->lock);
3916                 }
3917                 if (num_bytes) {
3918                         spin_lock(&space_info->lock);
3919                         space_info->bytes_may_use -= num_bytes;
3920                         trace_btrfs_space_reservation(fs_info, "space_info",
3921                                               (u64)(unsigned long)space_info,
3922                                               num_bytes, 0);
3923                         space_info->reservation_progress++;
3924                         spin_unlock(&space_info->lock);
3925                 }
3926         }
3927 }
3928
3929 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
3930                                    struct btrfs_block_rsv *dst, u64 num_bytes)
3931 {
3932         int ret;
3933
3934         ret = block_rsv_use_bytes(src, num_bytes);
3935         if (ret)
3936                 return ret;
3937
3938         block_rsv_add_bytes(dst, num_bytes, 1);
3939         return 0;
3940 }
3941
3942 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
3943 {
3944         memset(rsv, 0, sizeof(*rsv));
3945         spin_lock_init(&rsv->lock);
3946 }
3947
3948 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
3949 {
3950         struct btrfs_block_rsv *block_rsv;
3951         struct btrfs_fs_info *fs_info = root->fs_info;
3952
3953         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
3954         if (!block_rsv)
3955                 return NULL;
3956
3957         btrfs_init_block_rsv(block_rsv);
3958         block_rsv->space_info = __find_space_info(fs_info,
3959                                                   BTRFS_BLOCK_GROUP_METADATA);
3960         return block_rsv;
3961 }
3962
3963 void btrfs_free_block_rsv(struct btrfs_root *root,
3964                           struct btrfs_block_rsv *rsv)
3965 {
3966         btrfs_block_rsv_release(root, rsv, (u64)-1);
3967         kfree(rsv);
3968 }
3969
3970 static inline int __block_rsv_add(struct btrfs_root *root,
3971                                   struct btrfs_block_rsv *block_rsv,
3972                                   u64 num_bytes, int flush)
3973 {
3974         int ret;
3975
3976         if (num_bytes == 0)
3977                 return 0;
3978
3979         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
3980         if (!ret) {
3981                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
3982                 return 0;
3983         }
3984
3985         return ret;
3986 }
3987
3988 int btrfs_block_rsv_add(struct btrfs_root *root,
3989                         struct btrfs_block_rsv *block_rsv,
3990                         u64 num_bytes)
3991 {
3992         return __block_rsv_add(root, block_rsv, num_bytes, 1);
3993 }
3994
3995 int btrfs_block_rsv_add_noflush(struct btrfs_root *root,
3996                                 struct btrfs_block_rsv *block_rsv,
3997                                 u64 num_bytes)
3998 {
3999         return __block_rsv_add(root, block_rsv, num_bytes, 0);
4000 }
4001
4002 int btrfs_block_rsv_check(struct btrfs_root *root,
4003                           struct btrfs_block_rsv *block_rsv, int min_factor)
4004 {
4005         u64 num_bytes = 0;
4006         int ret = -ENOSPC;
4007
4008         if (!block_rsv)
4009                 return 0;
4010
4011         spin_lock(&block_rsv->lock);
4012         num_bytes = div_factor(block_rsv->size, min_factor);
4013         if (block_rsv->reserved >= num_bytes)
4014                 ret = 0;
4015         spin_unlock(&block_rsv->lock);
4016
4017         return ret;
4018 }
4019
4020 static inline int __btrfs_block_rsv_refill(struct btrfs_root *root,
4021                                            struct btrfs_block_rsv *block_rsv,
4022                                            u64 min_reserved, int flush)
4023 {
4024         u64 num_bytes = 0;
4025         int ret = -ENOSPC;
4026
4027         if (!block_rsv)
4028                 return 0;
4029
4030         spin_lock(&block_rsv->lock);
4031         num_bytes = min_reserved;
4032         if (block_rsv->reserved >= num_bytes)
4033                 ret = 0;
4034         else
4035                 num_bytes -= block_rsv->reserved;
4036         spin_unlock(&block_rsv->lock);
4037
4038         if (!ret)
4039                 return 0;
4040
4041         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4042         if (!ret) {
4043                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4044                 return 0;
4045         }
4046
4047         return ret;
4048 }
4049
4050 int btrfs_block_rsv_refill(struct btrfs_root *root,
4051                            struct btrfs_block_rsv *block_rsv,
4052                            u64 min_reserved)
4053 {
4054         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 1);
4055 }
4056
4057 int btrfs_block_rsv_refill_noflush(struct btrfs_root *root,
4058                                    struct btrfs_block_rsv *block_rsv,
4059                                    u64 min_reserved)
4060 {
4061         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 0);
4062 }
4063
4064 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4065                             struct btrfs_block_rsv *dst_rsv,
4066                             u64 num_bytes)
4067 {
4068         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4069 }
4070
4071 void btrfs_block_rsv_release(struct btrfs_root *root,
4072                              struct btrfs_block_rsv *block_rsv,
4073                              u64 num_bytes)
4074 {
4075         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4076         if (global_rsv->full || global_rsv == block_rsv ||
4077             block_rsv->space_info != global_rsv->space_info)
4078                 global_rsv = NULL;
4079         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4080                                 num_bytes);
4081 }
4082
4083 /*
4084  * helper to calculate size of global block reservation.
4085  * the desired value is sum of space used by extent tree,
4086  * checksum tree and root tree
4087  */
4088 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4089 {
4090         struct btrfs_space_info *sinfo;
4091         u64 num_bytes;
4092         u64 meta_used;
4093         u64 data_used;
4094         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4095
4096         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4097         spin_lock(&sinfo->lock);
4098         data_used = sinfo->bytes_used;
4099         spin_unlock(&sinfo->lock);
4100
4101         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4102         spin_lock(&sinfo->lock);
4103         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4104                 data_used = 0;
4105         meta_used = sinfo->bytes_used;
4106         spin_unlock(&sinfo->lock);
4107
4108         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4109                     csum_size * 2;
4110         num_bytes += div64_u64(data_used + meta_used, 50);
4111
4112         if (num_bytes * 3 > meta_used)
4113                 num_bytes = div64_u64(meta_used, 3) * 2;
4114
4115         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4116 }
4117
4118 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4119 {
4120         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4121         struct btrfs_space_info *sinfo = block_rsv->space_info;
4122         u64 num_bytes;
4123
4124         num_bytes = calc_global_metadata_size(fs_info);
4125
4126         spin_lock(&block_rsv->lock);
4127         spin_lock(&sinfo->lock);
4128
4129         block_rsv->size = num_bytes;
4130
4131         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4132                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4133                     sinfo->bytes_may_use;
4134
4135         if (sinfo->total_bytes > num_bytes) {
4136                 num_bytes = sinfo->total_bytes - num_bytes;
4137                 block_rsv->reserved += num_bytes;
4138                 sinfo->bytes_may_use += num_bytes;
4139                 trace_btrfs_space_reservation(fs_info, "space_info",
4140                                       (u64)(unsigned long)sinfo, num_bytes, 1);
4141         }
4142
4143         if (block_rsv->reserved >= block_rsv->size) {
4144                 num_bytes = block_rsv->reserved - block_rsv->size;
4145                 sinfo->bytes_may_use -= num_bytes;
4146                 trace_btrfs_space_reservation(fs_info, "space_info",
4147                                       (u64)(unsigned long)sinfo, num_bytes, 0);
4148                 sinfo->reservation_progress++;
4149                 block_rsv->reserved = block_rsv->size;
4150                 block_rsv->full = 1;
4151         }
4152
4153         spin_unlock(&sinfo->lock);
4154         spin_unlock(&block_rsv->lock);
4155 }
4156
4157 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4158 {
4159         struct btrfs_space_info *space_info;
4160
4161         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4162         fs_info->chunk_block_rsv.space_info = space_info;
4163
4164         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4165         fs_info->global_block_rsv.space_info = space_info;
4166         fs_info->delalloc_block_rsv.space_info = space_info;
4167         fs_info->trans_block_rsv.space_info = space_info;
4168         fs_info->empty_block_rsv.space_info = space_info;
4169         fs_info->delayed_block_rsv.space_info = space_info;
4170
4171         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4172         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4173         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4174         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4175         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4176
4177         update_global_block_rsv(fs_info);
4178 }
4179
4180 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4181 {
4182         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4183                                 (u64)-1);
4184         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4185         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4186         WARN_ON(fs_info->trans_block_rsv.size > 0);
4187         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4188         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4189         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4190         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4191         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4192 }
4193
4194 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4195                                   struct btrfs_root *root)
4196 {
4197         if (!trans->bytes_reserved)
4198                 return;
4199
4200         trace_btrfs_space_reservation(root->fs_info, "transaction",
4201                                       (u64)(unsigned long)trans,
4202                                       trans->bytes_reserved, 0);
4203         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4204         trans->bytes_reserved = 0;
4205 }
4206
4207 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4208                                   struct inode *inode)
4209 {
4210         struct btrfs_root *root = BTRFS_I(inode)->root;
4211         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4212         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4213
4214         /*
4215          * We need to hold space in order to delete our orphan item once we've
4216          * added it, so this takes the reservation so we can release it later
4217          * when we are truly done with the orphan item.
4218          */
4219         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4220         trace_btrfs_space_reservation(root->fs_info, "orphan",
4221                                       btrfs_ino(inode), num_bytes, 1);
4222         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4223 }
4224
4225 void btrfs_orphan_release_metadata(struct inode *inode)
4226 {
4227         struct btrfs_root *root = BTRFS_I(inode)->root;
4228         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4229         trace_btrfs_space_reservation(root->fs_info, "orphan",
4230                                       btrfs_ino(inode), num_bytes, 0);
4231         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4232 }
4233
4234 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
4235                                 struct btrfs_pending_snapshot *pending)
4236 {
4237         struct btrfs_root *root = pending->root;
4238         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4239         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
4240         /*
4241          * two for root back/forward refs, two for directory entries
4242          * and one for root of the snapshot.
4243          */
4244         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
4245         dst_rsv->space_info = src_rsv->space_info;
4246         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4247 }
4248
4249 /**
4250  * drop_outstanding_extent - drop an outstanding extent
4251  * @inode: the inode we're dropping the extent for
4252  *
4253  * This is called when we are freeing up an outstanding extent, either called
4254  * after an error or after an extent is written.  This will return the number of
4255  * reserved extents that need to be freed.  This must be called with
4256  * BTRFS_I(inode)->lock held.
4257  */
4258 static unsigned drop_outstanding_extent(struct inode *inode)
4259 {
4260         unsigned drop_inode_space = 0;
4261         unsigned dropped_extents = 0;
4262
4263         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4264         BTRFS_I(inode)->outstanding_extents--;
4265
4266         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4267             BTRFS_I(inode)->delalloc_meta_reserved) {
4268                 drop_inode_space = 1;
4269                 BTRFS_I(inode)->delalloc_meta_reserved = 0;
4270         }
4271
4272         /*
4273          * If we have more or the same amount of outsanding extents than we have
4274          * reserved then we need to leave the reserved extents count alone.
4275          */
4276         if (BTRFS_I(inode)->outstanding_extents >=
4277             BTRFS_I(inode)->reserved_extents)
4278                 return drop_inode_space;
4279
4280         dropped_extents = BTRFS_I(inode)->reserved_extents -
4281                 BTRFS_I(inode)->outstanding_extents;
4282         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4283         return dropped_extents + drop_inode_space;
4284 }
4285
4286 /**
4287  * calc_csum_metadata_size - return the amount of metada space that must be
4288  *      reserved/free'd for the given bytes.
4289  * @inode: the inode we're manipulating
4290  * @num_bytes: the number of bytes in question
4291  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4292  *
4293  * This adjusts the number of csum_bytes in the inode and then returns the
4294  * correct amount of metadata that must either be reserved or freed.  We
4295  * calculate how many checksums we can fit into one leaf and then divide the
4296  * number of bytes that will need to be checksumed by this value to figure out
4297  * how many checksums will be required.  If we are adding bytes then the number
4298  * may go up and we will return the number of additional bytes that must be
4299  * reserved.  If it is going down we will return the number of bytes that must
4300  * be freed.
4301  *
4302  * This must be called with BTRFS_I(inode)->lock held.
4303  */
4304 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4305                                    int reserve)
4306 {
4307         struct btrfs_root *root = BTRFS_I(inode)->root;
4308         u64 csum_size;
4309         int num_csums_per_leaf;
4310         int num_csums;
4311         int old_csums;
4312
4313         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4314             BTRFS_I(inode)->csum_bytes == 0)
4315                 return 0;
4316
4317         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4318         if (reserve)
4319                 BTRFS_I(inode)->csum_bytes += num_bytes;
4320         else
4321                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4322         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4323         num_csums_per_leaf = (int)div64_u64(csum_size,
4324                                             sizeof(struct btrfs_csum_item) +
4325                                             sizeof(struct btrfs_disk_key));
4326         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4327         num_csums = num_csums + num_csums_per_leaf - 1;
4328         num_csums = num_csums / num_csums_per_leaf;
4329
4330         old_csums = old_csums + num_csums_per_leaf - 1;
4331         old_csums = old_csums / num_csums_per_leaf;
4332
4333         /* No change, no need to reserve more */
4334         if (old_csums == num_csums)
4335                 return 0;
4336
4337         if (reserve)
4338                 return btrfs_calc_trans_metadata_size(root,
4339                                                       num_csums - old_csums);
4340
4341         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4342 }
4343
4344 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4345 {
4346         struct btrfs_root *root = BTRFS_I(inode)->root;
4347         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4348         u64 to_reserve = 0;
4349         u64 csum_bytes;
4350         unsigned nr_extents = 0;
4351         int extra_reserve = 0;
4352         int flush = 1;
4353         int ret;
4354
4355         /* Need to be holding the i_mutex here if we aren't free space cache */
4356         if (btrfs_is_free_space_inode(root, inode))
4357                 flush = 0;
4358
4359         if (flush && btrfs_transaction_in_commit(root->fs_info))
4360                 schedule_timeout(1);
4361
4362         mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4363         num_bytes = ALIGN(num_bytes, root->sectorsize);
4364
4365         spin_lock(&BTRFS_I(inode)->lock);
4366         BTRFS_I(inode)->outstanding_extents++;
4367
4368         if (BTRFS_I(inode)->outstanding_extents >
4369             BTRFS_I(inode)->reserved_extents)
4370                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4371                         BTRFS_I(inode)->reserved_extents;
4372
4373         /*
4374          * Add an item to reserve for updating the inode when we complete the
4375          * delalloc io.
4376          */
4377         if (!BTRFS_I(inode)->delalloc_meta_reserved) {
4378                 nr_extents++;
4379                 extra_reserve = 1;
4380         }
4381
4382         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4383         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4384         csum_bytes = BTRFS_I(inode)->csum_bytes;
4385         spin_unlock(&BTRFS_I(inode)->lock);
4386
4387         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4388         if (ret) {
4389                 u64 to_free = 0;
4390                 unsigned dropped;
4391
4392                 spin_lock(&BTRFS_I(inode)->lock);
4393                 dropped = drop_outstanding_extent(inode);
4394                 /*
4395                  * If the inodes csum_bytes is the same as the original
4396                  * csum_bytes then we know we haven't raced with any free()ers
4397                  * so we can just reduce our inodes csum bytes and carry on.
4398                  * Otherwise we have to do the normal free thing to account for
4399                  * the case that the free side didn't free up its reserve
4400                  * because of this outstanding reservation.
4401                  */
4402                 if (BTRFS_I(inode)->csum_bytes == csum_bytes)
4403                         calc_csum_metadata_size(inode, num_bytes, 0);
4404                 else
4405                         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4406                 spin_unlock(&BTRFS_I(inode)->lock);
4407                 if (dropped)
4408                         to_free += btrfs_calc_trans_metadata_size(root, dropped);
4409
4410                 if (to_free) {
4411                         btrfs_block_rsv_release(root, block_rsv, to_free);
4412                         trace_btrfs_space_reservation(root->fs_info,
4413                                                       "delalloc",
4414                                                       btrfs_ino(inode),
4415                                                       to_free, 0);
4416                 }
4417                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4418                 return ret;
4419         }
4420
4421         spin_lock(&BTRFS_I(inode)->lock);
4422         if (extra_reserve) {
4423                 BTRFS_I(inode)->delalloc_meta_reserved = 1;
4424                 nr_extents--;
4425         }
4426         BTRFS_I(inode)->reserved_extents += nr_extents;
4427         spin_unlock(&BTRFS_I(inode)->lock);
4428         mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4429
4430         if (to_reserve)
4431                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
4432                                               btrfs_ino(inode), to_reserve, 1);
4433         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4434
4435         return 0;
4436 }
4437
4438 /**
4439  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
4440  * @inode: the inode to release the reservation for
4441  * @num_bytes: the number of bytes we're releasing
4442  *
4443  * This will release the metadata reservation for an inode.  This can be called
4444  * once we complete IO for a given set of bytes to release their metadata
4445  * reservations.
4446  */
4447 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4448 {
4449         struct btrfs_root *root = BTRFS_I(inode)->root;
4450         u64 to_free = 0;
4451         unsigned dropped;
4452
4453         num_bytes = ALIGN(num_bytes, root->sectorsize);
4454         spin_lock(&BTRFS_I(inode)->lock);
4455         dropped = drop_outstanding_extent(inode);
4456
4457         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4458         spin_unlock(&BTRFS_I(inode)->lock);
4459         if (dropped > 0)
4460                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4461
4462         trace_btrfs_space_reservation(root->fs_info, "delalloc",
4463                                       btrfs_ino(inode), to_free, 0);
4464         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4465                                 to_free);
4466 }
4467
4468 /**
4469  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
4470  * @inode: inode we're writing to
4471  * @num_bytes: the number of bytes we want to allocate
4472  *
4473  * This will do the following things
4474  *
4475  * o reserve space in the data space info for num_bytes
4476  * o reserve space in the metadata space info based on number of outstanding
4477  *   extents and how much csums will be needed
4478  * o add to the inodes ->delalloc_bytes
4479  * o add it to the fs_info's delalloc inodes list.
4480  *
4481  * This will return 0 for success and -ENOSPC if there is no space left.
4482  */
4483 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4484 {
4485         int ret;
4486
4487         ret = btrfs_check_data_free_space(inode, num_bytes);
4488         if (ret)
4489                 return ret;
4490
4491         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4492         if (ret) {
4493                 btrfs_free_reserved_data_space(inode, num_bytes);
4494                 return ret;
4495         }
4496
4497         return 0;
4498 }
4499
4500 /**
4501  * btrfs_delalloc_release_space - release data and metadata space for delalloc
4502  * @inode: inode we're releasing space for
4503  * @num_bytes: the number of bytes we want to free up
4504  *
4505  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
4506  * called in the case that we don't need the metadata AND data reservations
4507  * anymore.  So if there is an error or we insert an inline extent.
4508  *
4509  * This function will release the metadata space that was not used and will
4510  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
4511  * list if there are no delalloc bytes left.
4512  */
4513 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4514 {
4515         btrfs_delalloc_release_metadata(inode, num_bytes);
4516         btrfs_free_reserved_data_space(inode, num_bytes);
4517 }
4518
4519 static int update_block_group(struct btrfs_trans_handle *trans,
4520                               struct btrfs_root *root,
4521                               u64 bytenr, u64 num_bytes, int alloc)
4522 {
4523         struct btrfs_block_group_cache *cache = NULL;
4524         struct btrfs_fs_info *info = root->fs_info;
4525         u64 total = num_bytes;
4526         u64 old_val;
4527         u64 byte_in_group;
4528         int factor;
4529
4530         /* block accounting for super block */
4531         spin_lock(&info->delalloc_lock);
4532         old_val = btrfs_super_bytes_used(info->super_copy);
4533         if (alloc)
4534                 old_val += num_bytes;
4535         else
4536                 old_val -= num_bytes;
4537         btrfs_set_super_bytes_used(info->super_copy, old_val);
4538         spin_unlock(&info->delalloc_lock);
4539
4540         while (total) {
4541                 cache = btrfs_lookup_block_group(info, bytenr);
4542                 if (!cache)
4543                         return -1;
4544                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4545                                     BTRFS_BLOCK_GROUP_RAID1 |
4546                                     BTRFS_BLOCK_GROUP_RAID10))
4547                         factor = 2;
4548                 else
4549                         factor = 1;
4550                 /*
4551                  * If this block group has free space cache written out, we
4552                  * need to make sure to load it if we are removing space.  This
4553                  * is because we need the unpinning stage to actually add the
4554                  * space back to the block group, otherwise we will leak space.
4555                  */
4556                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4557                         cache_block_group(cache, trans, NULL, 1);
4558
4559                 byte_in_group = bytenr - cache->key.objectid;
4560                 WARN_ON(byte_in_group > cache->key.offset);
4561
4562                 spin_lock(&cache->space_info->lock);
4563                 spin_lock(&cache->lock);
4564
4565                 if (btrfs_test_opt(root, SPACE_CACHE) &&
4566                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4567                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4568
4569                 cache->dirty = 1;
4570                 old_val = btrfs_block_group_used(&cache->item);
4571                 num_bytes = min(total, cache->key.offset - byte_in_group);
4572                 if (alloc) {
4573                         old_val += num_bytes;
4574                         btrfs_set_block_group_used(&cache->item, old_val);
4575                         cache->reserved -= num_bytes;
4576                         cache->space_info->bytes_reserved -= num_bytes;
4577                         cache->space_info->bytes_used += num_bytes;
4578                         cache->space_info->disk_used += num_bytes * factor;
4579                         spin_unlock(&cache->lock);
4580                         spin_unlock(&cache->space_info->lock);
4581                 } else {
4582                         old_val -= num_bytes;
4583                         btrfs_set_block_group_used(&cache->item, old_val);
4584                         cache->pinned += num_bytes;
4585                         cache->space_info->bytes_pinned += num_bytes;
4586                         cache->space_info->bytes_used -= num_bytes;
4587                         cache->space_info->disk_used -= num_bytes * factor;
4588                         spin_unlock(&cache->lock);
4589                         spin_unlock(&cache->space_info->lock);
4590
4591                         set_extent_dirty(info->pinned_extents,
4592                                          bytenr, bytenr + num_bytes - 1,
4593                                          GFP_NOFS | __GFP_NOFAIL);
4594                 }
4595                 btrfs_put_block_group(cache);
4596                 total -= num_bytes;
4597                 bytenr += num_bytes;
4598         }
4599         return 0;
4600 }
4601
4602 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4603 {
4604         struct btrfs_block_group_cache *cache;
4605         u64 bytenr;
4606
4607         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4608         if (!cache)
4609                 return 0;
4610
4611         bytenr = cache->key.objectid;
4612         btrfs_put_block_group(cache);
4613
4614         return bytenr;
4615 }
4616
4617 static int pin_down_extent(struct btrfs_root *root,
4618                            struct btrfs_block_group_cache *cache,
4619                            u64 bytenr, u64 num_bytes, int reserved)
4620 {
4621         spin_lock(&cache->space_info->lock);
4622         spin_lock(&cache->lock);
4623         cache->pinned += num_bytes;
4624         cache->space_info->bytes_pinned += num_bytes;
4625         if (reserved) {
4626                 cache->reserved -= num_bytes;
4627                 cache->space_info->bytes_reserved -= num_bytes;
4628         }
4629         spin_unlock(&cache->lock);
4630         spin_unlock(&cache->space_info->lock);
4631
4632         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4633                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4634         return 0;
4635 }
4636
4637 /*
4638  * this function must be called within transaction
4639  */
4640 int btrfs_pin_extent(struct btrfs_root *root,
4641                      u64 bytenr, u64 num_bytes, int reserved)
4642 {
4643         struct btrfs_block_group_cache *cache;
4644
4645         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4646         BUG_ON(!cache);
4647
4648         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4649
4650         btrfs_put_block_group(cache);
4651         return 0;
4652 }
4653
4654 /*
4655  * this function must be called within transaction
4656  */
4657 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
4658                                     struct btrfs_root *root,
4659                                     u64 bytenr, u64 num_bytes)
4660 {
4661         struct btrfs_block_group_cache *cache;
4662
4663         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4664         BUG_ON(!cache);
4665
4666         /*
4667          * pull in the free space cache (if any) so that our pin
4668          * removes the free space from the cache.  We have load_only set
4669          * to one because the slow code to read in the free extents does check
4670          * the pinned extents.
4671          */
4672         cache_block_group(cache, trans, root, 1);
4673
4674         pin_down_extent(root, cache, bytenr, num_bytes, 0);
4675
4676         /* remove us from the free space cache (if we're there at all) */
4677         btrfs_remove_free_space(cache, bytenr, num_bytes);
4678         btrfs_put_block_group(cache);
4679         return 0;
4680 }
4681
4682 /**
4683  * btrfs_update_reserved_bytes - update the block_group and space info counters
4684  * @cache:      The cache we are manipulating
4685  * @num_bytes:  The number of bytes in question
4686  * @reserve:    One of the reservation enums
4687  *
4688  * This is called by the allocator when it reserves space, or by somebody who is
4689  * freeing space that was never actually used on disk.  For example if you
4690  * reserve some space for a new leaf in transaction A and before transaction A
4691  * commits you free that leaf, you call this with reserve set to 0 in order to
4692  * clear the reservation.
4693  *
4694  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
4695  * ENOSPC accounting.  For data we handle the reservation through clearing the
4696  * delalloc bits in the io_tree.  We have to do this since we could end up
4697  * allocating less disk space for the amount of data we have reserved in the
4698  * case of compression.
4699  *
4700  * If this is a reservation and the block group has become read only we cannot
4701  * make the reservation and return -EAGAIN, otherwise this function always
4702  * succeeds.
4703  */
4704 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4705                                        u64 num_bytes, int reserve)
4706 {
4707         struct btrfs_space_info *space_info = cache->space_info;
4708         int ret = 0;
4709         spin_lock(&space_info->lock);
4710         spin_lock(&cache->lock);
4711         if (reserve != RESERVE_FREE) {
4712                 if (cache->ro) {
4713                         ret = -EAGAIN;
4714                 } else {
4715                         cache->reserved += num_bytes;
4716                         space_info->bytes_reserved += num_bytes;
4717                         if (reserve == RESERVE_ALLOC) {
4718                                 trace_btrfs_space_reservation(cache->fs_info,
4719                                               "space_info",
4720                                               (u64)(unsigned long)space_info,
4721                                               num_bytes, 0);
4722                                 space_info->bytes_may_use -= num_bytes;
4723                         }
4724                 }
4725         } else {
4726                 if (cache->ro)
4727                         space_info->bytes_readonly += num_bytes;
4728                 cache->reserved -= num_bytes;
4729                 space_info->bytes_reserved -= num_bytes;
4730                 space_info->reservation_progress++;
4731         }
4732         spin_unlock(&cache->lock);
4733         spin_unlock(&space_info->lock);
4734         return ret;
4735 }
4736
4737 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4738                                 struct btrfs_root *root)
4739 {
4740         struct btrfs_fs_info *fs_info = root->fs_info;
4741         struct btrfs_caching_control *next;
4742         struct btrfs_caching_control *caching_ctl;
4743         struct btrfs_block_group_cache *cache;
4744
4745         down_write(&fs_info->extent_commit_sem);
4746
4747         list_for_each_entry_safe(caching_ctl, next,
4748                                  &fs_info->caching_block_groups, list) {
4749                 cache = caching_ctl->block_group;
4750                 if (block_group_cache_done(cache)) {
4751                         cache->last_byte_to_unpin = (u64)-1;
4752                         list_del_init(&caching_ctl->list);
4753                         put_caching_control(caching_ctl);
4754                 } else {
4755                         cache->last_byte_to_unpin = caching_ctl->progress;
4756                 }
4757         }
4758
4759         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4760                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4761         else
4762                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4763
4764         up_write(&fs_info->extent_commit_sem);
4765
4766         update_global_block_rsv(fs_info);
4767         return 0;
4768 }
4769
4770 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4771 {
4772         struct btrfs_fs_info *fs_info = root->fs_info;
4773         struct btrfs_block_group_cache *cache = NULL;
4774         u64 len;
4775
4776         while (start <= end) {
4777                 if (!cache ||
4778                     start >= cache->key.objectid + cache->key.offset) {
4779                         if (cache)
4780                                 btrfs_put_block_group(cache);
4781                         cache = btrfs_lookup_block_group(fs_info, start);
4782                         BUG_ON(!cache);
4783                 }
4784
4785                 len = cache->key.objectid + cache->key.offset - start;
4786                 len = min(len, end + 1 - start);
4787
4788                 if (start < cache->last_byte_to_unpin) {
4789                         len = min(len, cache->last_byte_to_unpin - start);
4790                         btrfs_add_free_space(cache, start, len);
4791                 }
4792
4793                 start += len;
4794
4795                 spin_lock(&cache->space_info->lock);
4796                 spin_lock(&cache->lock);
4797                 cache->pinned -= len;
4798                 cache->space_info->bytes_pinned -= len;
4799                 if (cache->ro)
4800                         cache->space_info->bytes_readonly += len;
4801                 spin_unlock(&cache->lock);
4802                 spin_unlock(&cache->space_info->lock);
4803         }
4804
4805         if (cache)
4806                 btrfs_put_block_group(cache);
4807         return 0;
4808 }
4809
4810 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4811                                struct btrfs_root *root)
4812 {
4813         struct btrfs_fs_info *fs_info = root->fs_info;
4814         struct extent_io_tree *unpin;
4815         u64 start;
4816         u64 end;
4817         int ret;
4818
4819         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4820                 unpin = &fs_info->freed_extents[1];
4821         else
4822                 unpin = &fs_info->freed_extents[0];
4823
4824         while (1) {
4825                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4826                                             EXTENT_DIRTY);
4827                 if (ret)
4828                         break;
4829
4830                 if (btrfs_test_opt(root, DISCARD))
4831                         ret = btrfs_discard_extent(root, start,
4832                                                    end + 1 - start, NULL);
4833
4834                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4835                 unpin_extent_range(root, start, end);
4836                 cond_resched();
4837         }
4838
4839         return 0;
4840 }
4841
4842 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
4843                                 struct btrfs_root *root,
4844                                 u64 bytenr, u64 num_bytes, u64 parent,
4845                                 u64 root_objectid, u64 owner_objectid,
4846                                 u64 owner_offset, int refs_to_drop,
4847                                 struct btrfs_delayed_extent_op *extent_op)
4848 {
4849         struct btrfs_key key;
4850         struct btrfs_path *path;
4851         struct btrfs_fs_info *info = root->fs_info;
4852         struct btrfs_root *extent_root = info->extent_root;
4853         struct extent_buffer *leaf;
4854         struct btrfs_extent_item *ei;
4855         struct btrfs_extent_inline_ref *iref;
4856         int ret;
4857         int is_data;
4858         int extent_slot = 0;
4859         int found_extent = 0;
4860         int num_to_del = 1;
4861         u32 item_size;
4862         u64 refs;
4863
4864         path = btrfs_alloc_path();
4865         if (!path)
4866                 return -ENOMEM;
4867
4868         path->reada = 1;
4869         path->leave_spinning = 1;
4870
4871         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
4872         BUG_ON(!is_data && refs_to_drop != 1);
4873
4874         ret = lookup_extent_backref(trans, extent_root, path, &iref,
4875                                     bytenr, num_bytes, parent,
4876                                     root_objectid, owner_objectid,
4877                                     owner_offset);
4878         if (ret == 0) {
4879                 extent_slot = path->slots[0];
4880                 while (extent_slot >= 0) {
4881                         btrfs_item_key_to_cpu(path->nodes[0], &key,
4882                                               extent_slot);
4883                         if (key.objectid != bytenr)
4884                                 break;
4885                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
4886                             key.offset == num_bytes) {
4887                                 found_extent = 1;
4888                                 break;
4889                         }
4890                         if (path->slots[0] - extent_slot > 5)
4891                                 break;
4892                         extent_slot--;
4893                 }
4894 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4895                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
4896                 if (found_extent && item_size < sizeof(*ei))
4897                         found_extent = 0;
4898 #endif
4899                 if (!found_extent) {
4900                         BUG_ON(iref);
4901                         ret = remove_extent_backref(trans, extent_root, path,
4902                                                     NULL, refs_to_drop,
4903                                                     is_data);
4904                         BUG_ON(ret);
4905                         btrfs_release_path(path);
4906                         path->leave_spinning = 1;
4907
4908                         key.objectid = bytenr;
4909                         key.type = BTRFS_EXTENT_ITEM_KEY;
4910                         key.offset = num_bytes;
4911
4912                         ret = btrfs_search_slot(trans, extent_root,
4913                                                 &key, path, -1, 1);
4914                         if (ret) {
4915                                 printk(KERN_ERR "umm, got %d back from search"
4916                                        ", was looking for %llu\n", ret,
4917                                        (unsigned long long)bytenr);
4918                                 if (ret > 0)
4919                                         btrfs_print_leaf(extent_root,
4920                                                          path->nodes[0]);
4921                         }
4922                         BUG_ON(ret);
4923                         extent_slot = path->slots[0];
4924                 }
4925         } else {
4926                 btrfs_print_leaf(extent_root, path->nodes[0]);
4927                 WARN_ON(1);
4928                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
4929                        "parent %llu root %llu  owner %llu offset %llu\n",
4930                        (unsigned long long)bytenr,
4931                        (unsigned long long)parent,
4932                        (unsigned long long)root_objectid,
4933                        (unsigned long long)owner_objectid,
4934                        (unsigned long long)owner_offset);
4935         }
4936
4937         leaf = path->nodes[0];
4938         item_size = btrfs_item_size_nr(leaf, extent_slot);
4939 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4940         if (item_size < sizeof(*ei)) {
4941                 BUG_ON(found_extent || extent_slot != path->slots[0]);
4942                 ret = convert_extent_item_v0(trans, extent_root, path,
4943                                              owner_objectid, 0);
4944                 BUG_ON(ret < 0);
4945
4946                 btrfs_release_path(path);
4947                 path->leave_spinning = 1;
4948
4949                 key.objectid = bytenr;
4950                 key.type = BTRFS_EXTENT_ITEM_KEY;
4951                 key.offset = num_bytes;
4952
4953                 ret = btrfs_search_slot(trans, extent_root, &key, path,
4954                                         -1, 1);
4955                 if (ret) {
4956                         printk(KERN_ERR "umm, got %d back from search"
4957                                ", was looking for %llu\n", ret,
4958                                (unsigned long long)bytenr);
4959                         btrfs_print_leaf(extent_root, path->nodes[0]);
4960                 }
4961                 BUG_ON(ret);
4962                 extent_slot = path->slots[0];
4963                 leaf = path->nodes[0];
4964                 item_size = btrfs_item_size_nr(leaf, extent_slot);
4965         }
4966 #endif
4967         BUG_ON(item_size < sizeof(*ei));
4968         ei = btrfs_item_ptr(leaf, extent_slot,
4969                             struct btrfs_extent_item);
4970         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4971                 struct btrfs_tree_block_info *bi;
4972                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
4973                 bi = (struct btrfs_tree_block_info *)(ei + 1);
4974                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
4975         }
4976
4977         refs = btrfs_extent_refs(leaf, ei);
4978         BUG_ON(refs < refs_to_drop);
4979         refs -= refs_to_drop;
4980
4981         if (refs > 0) {
4982                 if (extent_op)
4983                         __run_delayed_extent_op(extent_op, leaf, ei);
4984                 /*
4985                  * In the case of inline back ref, reference count will
4986                  * be updated by remove_extent_backref
4987                  */
4988                 if (iref) {
4989                         BUG_ON(!found_extent);
4990                 } else {
4991                         btrfs_set_extent_refs(leaf, ei, refs);
4992                         btrfs_mark_buffer_dirty(leaf);
4993                 }
4994                 if (found_extent) {
4995                         ret = remove_extent_backref(trans, extent_root, path,
4996                                                     iref, refs_to_drop,
4997                                                     is_data);
4998                         BUG_ON(ret);
4999                 }
5000         } else {
5001                 if (found_extent) {
5002                         BUG_ON(is_data && refs_to_drop !=
5003                                extent_data_ref_count(root, path, iref));
5004                         if (iref) {
5005                                 BUG_ON(path->slots[0] != extent_slot);
5006                         } else {
5007                                 BUG_ON(path->slots[0] != extent_slot + 1);
5008                                 path->slots[0] = extent_slot;
5009                                 num_to_del = 2;
5010                         }
5011                 }
5012
5013                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5014                                       num_to_del);
5015                 BUG_ON(ret);
5016                 btrfs_release_path(path);
5017
5018                 if (is_data) {
5019                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5020                         BUG_ON(ret);
5021                 } else {
5022                         invalidate_mapping_pages(info->btree_inode->i_mapping,
5023                              bytenr >> PAGE_CACHE_SHIFT,
5024                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
5025                 }
5026
5027                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
5028                 BUG_ON(ret);
5029         }
5030         btrfs_free_path(path);
5031         return ret;
5032 }
5033
5034 /*
5035  * when we free an block, it is possible (and likely) that we free the last
5036  * delayed ref for that extent as well.  This searches the delayed ref tree for
5037  * a given extent, and if there are no other delayed refs to be processed, it
5038  * removes it from the tree.
5039  */
5040 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5041                                       struct btrfs_root *root, u64 bytenr)
5042 {
5043         struct btrfs_delayed_ref_head *head;
5044         struct btrfs_delayed_ref_root *delayed_refs;
5045         struct btrfs_delayed_ref_node *ref;
5046         struct rb_node *node;
5047         int ret = 0;
5048
5049         delayed_refs = &trans->transaction->delayed_refs;
5050         spin_lock(&delayed_refs->lock);
5051         head = btrfs_find_delayed_ref_head(trans, bytenr);
5052         if (!head)
5053                 goto out;
5054
5055         node = rb_prev(&head->node.rb_node);
5056         if (!node)
5057                 goto out;
5058
5059         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5060
5061         /* there are still entries for this ref, we can't drop it */
5062         if (ref->bytenr == bytenr)
5063                 goto out;
5064
5065         if (head->extent_op) {
5066                 if (!head->must_insert_reserved)
5067                         goto out;
5068                 kfree(head->extent_op);
5069                 head->extent_op = NULL;
5070         }
5071
5072         /*
5073          * waiting for the lock here would deadlock.  If someone else has it
5074          * locked they are already in the process of dropping it anyway
5075          */
5076         if (!mutex_trylock(&head->mutex))
5077                 goto out;
5078
5079         /*
5080          * at this point we have a head with no other entries.  Go
5081          * ahead and process it.
5082          */
5083         head->node.in_tree = 0;
5084         rb_erase(&head->node.rb_node, &delayed_refs->root);
5085
5086         delayed_refs->num_entries--;
5087         if (waitqueue_active(&delayed_refs->seq_wait))
5088                 wake_up(&delayed_refs->seq_wait);
5089
5090         /*
5091          * we don't take a ref on the node because we're removing it from the
5092          * tree, so we just steal the ref the tree was holding.
5093          */
5094         delayed_refs->num_heads--;
5095         if (list_empty(&head->cluster))
5096                 delayed_refs->num_heads_ready--;
5097
5098         list_del_init(&head->cluster);
5099         spin_unlock(&delayed_refs->lock);
5100
5101         BUG_ON(head->extent_op);
5102         if (head->must_insert_reserved)
5103                 ret = 1;
5104
5105         mutex_unlock(&head->mutex);
5106         btrfs_put_delayed_ref(&head->node);
5107         return ret;
5108 out:
5109         spin_unlock(&delayed_refs->lock);
5110         return 0;
5111 }
5112
5113 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5114                            struct btrfs_root *root,
5115                            struct extent_buffer *buf,
5116                            u64 parent, int last_ref, int for_cow)
5117 {
5118         struct btrfs_block_group_cache *cache = NULL;
5119         int ret;
5120
5121         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5122                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5123                                         buf->start, buf->len,
5124                                         parent, root->root_key.objectid,
5125                                         btrfs_header_level(buf),
5126                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5127                 BUG_ON(ret);
5128         }
5129
5130         if (!last_ref)
5131                 return;
5132
5133         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5134
5135         if (btrfs_header_generation(buf) == trans->transid) {
5136                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5137                         ret = check_ref_cleanup(trans, root, buf->start);
5138                         if (!ret)
5139                                 goto out;
5140                 }
5141
5142                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5143                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5144                         goto out;
5145                 }
5146
5147                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5148
5149                 btrfs_add_free_space(cache, buf->start, buf->len);
5150                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5151         }
5152 out:
5153         /*
5154          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5155          * anymore.
5156          */
5157         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5158         btrfs_put_block_group(cache);
5159 }
5160
5161 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5162                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
5163                       u64 owner, u64 offset, int for_cow)
5164 {
5165         int ret;
5166         struct btrfs_fs_info *fs_info = root->fs_info;
5167
5168         /*
5169          * tree log blocks never actually go into the extent allocation
5170          * tree, just update pinning info and exit early.
5171          */
5172         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5173                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5174                 /* unlocks the pinned mutex */
5175                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5176                 ret = 0;
5177         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5178                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
5179                                         num_bytes,
5180                                         parent, root_objectid, (int)owner,
5181                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5182                 BUG_ON(ret);
5183         } else {
5184                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
5185                                                 num_bytes,
5186                                                 parent, root_objectid, owner,
5187                                                 offset, BTRFS_DROP_DELAYED_REF,
5188                                                 NULL, for_cow);
5189                 BUG_ON(ret);
5190         }
5191         return ret;
5192 }
5193
5194 static u64 stripe_align(struct btrfs_root *root, u64 val)
5195 {
5196         u64 mask = ((u64)root->stripesize - 1);
5197         u64 ret = (val + mask) & ~mask;
5198         return ret;
5199 }
5200
5201 /*
5202  * when we wait for progress in the block group caching, its because
5203  * our allocation attempt failed at least once.  So, we must sleep
5204  * and let some progress happen before we try again.
5205  *
5206  * This function will sleep at least once waiting for new free space to
5207  * show up, and then it will check the block group free space numbers
5208  * for our min num_bytes.  Another option is to have it go ahead
5209  * and look in the rbtree for a free extent of a given size, but this
5210  * is a good start.
5211  */
5212 static noinline int
5213 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
5214                                 u64 num_bytes)
5215 {
5216         struct btrfs_caching_control *caching_ctl;
5217         DEFINE_WAIT(wait);
5218
5219         caching_ctl = get_caching_control(cache);
5220         if (!caching_ctl)
5221                 return 0;
5222
5223         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
5224                    (cache->free_space_ctl->free_space >= num_bytes));
5225
5226         put_caching_control(caching_ctl);
5227         return 0;
5228 }
5229
5230 static noinline int
5231 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
5232 {
5233         struct btrfs_caching_control *caching_ctl;
5234         DEFINE_WAIT(wait);
5235
5236         caching_ctl = get_caching_control(cache);
5237         if (!caching_ctl)
5238                 return 0;
5239
5240         wait_event(caching_ctl->wait, block_group_cache_done(cache));
5241
5242         put_caching_control(caching_ctl);
5243         return 0;
5244 }
5245
5246 static int get_block_group_index(struct btrfs_block_group_cache *cache)
5247 {
5248         int index;
5249         if (cache->flags & BTRFS_BLOCK_GROUP_RAID10)
5250                 index = 0;
5251         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID1)
5252                 index = 1;
5253         else if (cache->flags & BTRFS_BLOCK_GROUP_DUP)
5254                 index = 2;
5255         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID0)
5256                 index = 3;
5257         else
5258                 index = 4;
5259         return index;
5260 }
5261
5262 enum btrfs_loop_type {
5263         LOOP_CACHING_NOWAIT = 0,
5264         LOOP_CACHING_WAIT = 1,
5265         LOOP_ALLOC_CHUNK = 2,
5266         LOOP_NO_EMPTY_SIZE = 3,
5267 };
5268
5269 /*
5270  * walks the btree of allocated extents and find a hole of a given size.
5271  * The key ins is changed to record the hole:
5272  * ins->objectid == block start
5273  * ins->flags = BTRFS_EXTENT_ITEM_KEY
5274  * ins->offset == number of blocks
5275  * Any available blocks before search_start are skipped.
5276  */
5277 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
5278                                      struct btrfs_root *orig_root,
5279                                      u64 num_bytes, u64 empty_size,
5280                                      u64 search_start, u64 search_end,
5281                                      u64 hint_byte, struct btrfs_key *ins,
5282                                      u64 data)
5283 {
5284         int ret = 0;
5285         struct btrfs_root *root = orig_root->fs_info->extent_root;
5286         struct btrfs_free_cluster *last_ptr = NULL;
5287         struct btrfs_block_group_cache *block_group = NULL;
5288         struct btrfs_block_group_cache *used_block_group;
5289         int empty_cluster = 2 * 1024 * 1024;
5290         int allowed_chunk_alloc = 0;
5291         int done_chunk_alloc = 0;
5292         struct btrfs_space_info *space_info;
5293         int loop = 0;
5294         int index = 0;
5295         int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ?
5296                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
5297         bool found_uncached_bg = false;
5298         bool failed_cluster_refill = false;
5299         bool failed_alloc = false;
5300         bool use_cluster = true;
5301         bool have_caching_bg = false;
5302
5303         WARN_ON(num_bytes < root->sectorsize);
5304         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
5305         ins->objectid = 0;
5306         ins->offset = 0;
5307
5308         trace_find_free_extent(orig_root, num_bytes, empty_size, data);
5309
5310         space_info = __find_space_info(root->fs_info, data);
5311         if (!space_info) {
5312                 printk(KERN_ERR "No space info for %llu\n", data);
5313                 return -ENOSPC;
5314         }
5315
5316         /*
5317          * If the space info is for both data and metadata it means we have a
5318          * small filesystem and we can't use the clustering stuff.
5319          */
5320         if (btrfs_mixed_space_info(space_info))
5321                 use_cluster = false;
5322
5323         if (orig_root->ref_cows || empty_size)
5324                 allowed_chunk_alloc = 1;
5325
5326         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
5327                 last_ptr = &root->fs_info->meta_alloc_cluster;
5328                 if (!btrfs_test_opt(root, SSD))
5329                         empty_cluster = 64 * 1024;
5330         }
5331
5332         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
5333             btrfs_test_opt(root, SSD)) {
5334                 last_ptr = &root->fs_info->data_alloc_cluster;
5335         }
5336
5337         if (last_ptr) {
5338                 spin_lock(&last_ptr->lock);
5339                 if (last_ptr->block_group)
5340                         hint_byte = last_ptr->window_start;
5341                 spin_unlock(&last_ptr->lock);
5342         }
5343
5344         search_start = max(search_start, first_logical_byte(root, 0));
5345         search_start = max(search_start, hint_byte);
5346
5347         if (!last_ptr)
5348                 empty_cluster = 0;
5349
5350         if (search_start == hint_byte) {
5351                 block_group = btrfs_lookup_block_group(root->fs_info,
5352                                                        search_start);
5353                 used_block_group = block_group;
5354                 /*
5355                  * we don't want to use the block group if it doesn't match our
5356                  * allocation bits, or if its not cached.
5357                  *
5358                  * However if we are re-searching with an ideal block group
5359                  * picked out then we don't care that the block group is cached.
5360                  */
5361                 if (block_group && block_group_bits(block_group, data) &&
5362                     block_group->cached != BTRFS_CACHE_NO) {
5363                         down_read(&space_info->groups_sem);
5364                         if (list_empty(&block_group->list) ||
5365                             block_group->ro) {
5366                                 /*
5367                                  * someone is removing this block group,
5368                                  * we can't jump into the have_block_group
5369                                  * target because our list pointers are not
5370                                  * valid
5371                                  */
5372                                 btrfs_put_block_group(block_group);
5373                                 up_read(&space_info->groups_sem);
5374                         } else {
5375                                 index = get_block_group_index(block_group);
5376                                 goto have_block_group;
5377                         }
5378                 } else if (block_group) {
5379                         btrfs_put_block_group(block_group);
5380                 }
5381         }
5382 search:
5383         have_caching_bg = false;
5384         down_read(&space_info->groups_sem);
5385         list_for_each_entry(block_group, &space_info->block_groups[index],
5386                             list) {
5387                 u64 offset;
5388                 int cached;
5389
5390                 used_block_group = block_group;
5391                 btrfs_get_block_group(block_group);
5392                 search_start = block_group->key.objectid;
5393
5394                 /*
5395                  * this can happen if we end up cycling through all the
5396                  * raid types, but we want to make sure we only allocate
5397                  * for the proper type.
5398                  */
5399                 if (!block_group_bits(block_group, data)) {
5400                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
5401                                 BTRFS_BLOCK_GROUP_RAID1 |
5402                                 BTRFS_BLOCK_GROUP_RAID10;
5403
5404                         /*
5405                          * if they asked for extra copies and this block group
5406                          * doesn't provide them, bail.  This does allow us to
5407                          * fill raid0 from raid1.
5408                          */
5409                         if ((data & extra) && !(block_group->flags & extra))
5410                                 goto loop;
5411                 }
5412
5413 have_block_group:
5414                 cached = block_group_cache_done(block_group);
5415                 if (unlikely(!cached)) {
5416                         found_uncached_bg = true;
5417                         ret = cache_block_group(block_group, trans,
5418                                                 orig_root, 0);
5419                         BUG_ON(ret);
5420                 }
5421
5422                 if (unlikely(block_group->ro))
5423                         goto loop;
5424
5425                 /*
5426                  * Ok we want to try and use the cluster allocator, so
5427                  * lets look there
5428                  */
5429                 if (last_ptr) {
5430                         /*
5431                          * the refill lock keeps out other
5432                          * people trying to start a new cluster
5433                          */
5434                         spin_lock(&last_ptr->refill_lock);
5435                         used_block_group = last_ptr->block_group;
5436                         if (used_block_group != block_group &&
5437                             (!used_block_group ||
5438                              used_block_group->ro ||
5439                              !block_group_bits(used_block_group, data))) {
5440                                 used_block_group = block_group;
5441                                 goto refill_cluster;
5442                         }
5443
5444                         if (used_block_group != block_group)
5445                                 btrfs_get_block_group(used_block_group);
5446
5447                         offset = btrfs_alloc_from_cluster(used_block_group,
5448                           last_ptr, num_bytes, used_block_group->key.objectid);
5449                         if (offset) {
5450                                 /* we have a block, we're done */
5451                                 spin_unlock(&last_ptr->refill_lock);
5452                                 trace_btrfs_reserve_extent_cluster(root,
5453                                         block_group, search_start, num_bytes);
5454                                 goto checks;
5455                         }
5456
5457                         WARN_ON(last_ptr->block_group != used_block_group);
5458                         if (used_block_group != block_group) {
5459                                 btrfs_put_block_group(used_block_group);
5460                                 used_block_group = block_group;
5461                         }
5462 refill_cluster:
5463                         BUG_ON(used_block_group != block_group);
5464                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
5465                          * set up a new clusters, so lets just skip it
5466                          * and let the allocator find whatever block
5467                          * it can find.  If we reach this point, we
5468                          * will have tried the cluster allocator
5469                          * plenty of times and not have found
5470                          * anything, so we are likely way too
5471                          * fragmented for the clustering stuff to find
5472                          * anything.
5473                          *
5474                          * However, if the cluster is taken from the
5475                          * current block group, release the cluster
5476                          * first, so that we stand a better chance of
5477                          * succeeding in the unclustered
5478                          * allocation.  */
5479                         if (loop >= LOOP_NO_EMPTY_SIZE &&
5480                             last_ptr->block_group != block_group) {
5481                                 spin_unlock(&last_ptr->refill_lock);
5482                                 goto unclustered_alloc;
5483                         }
5484
5485                         /*
5486                          * this cluster didn't work out, free it and
5487                          * start over
5488                          */
5489                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5490
5491                         if (loop >= LOOP_NO_EMPTY_SIZE) {
5492                                 spin_unlock(&last_ptr->refill_lock);
5493                                 goto unclustered_alloc;
5494                         }
5495
5496                         /* allocate a cluster in this block group */
5497                         ret = btrfs_find_space_cluster(trans, root,
5498                                                block_group, last_ptr,
5499                                                search_start, num_bytes,
5500                                                empty_cluster + empty_size);
5501                         if (ret == 0) {
5502                                 /*
5503                                  * now pull our allocation out of this
5504                                  * cluster
5505                                  */
5506                                 offset = btrfs_alloc_from_cluster(block_group,
5507                                                   last_ptr, num_bytes,
5508                                                   search_start);
5509                                 if (offset) {
5510                                         /* we found one, proceed */
5511                                         spin_unlock(&last_ptr->refill_lock);
5512                                         trace_btrfs_reserve_extent_cluster(root,
5513                                                 block_group, search_start,
5514                                                 num_bytes);
5515                                         goto checks;
5516                                 }
5517                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5518                                    && !failed_cluster_refill) {
5519                                 spin_unlock(&last_ptr->refill_lock);
5520
5521                                 failed_cluster_refill = true;
5522                                 wait_block_group_cache_progress(block_group,
5523                                        num_bytes + empty_cluster + empty_size);
5524                                 goto have_block_group;
5525                         }
5526
5527                         /*
5528                          * at this point we either didn't find a cluster
5529                          * or we weren't able to allocate a block from our
5530                          * cluster.  Free the cluster we've been trying
5531                          * to use, and go to the next block group
5532                          */
5533                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5534                         spin_unlock(&last_ptr->refill_lock);
5535                         goto loop;
5536                 }
5537
5538 unclustered_alloc:
5539                 spin_lock(&block_group->free_space_ctl->tree_lock);
5540                 if (cached &&
5541                     block_group->free_space_ctl->free_space <
5542                     num_bytes + empty_cluster + empty_size) {
5543                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5544                         goto loop;
5545                 }
5546                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5547
5548                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5549                                                     num_bytes, empty_size);
5550                 /*
5551                  * If we didn't find a chunk, and we haven't failed on this
5552                  * block group before, and this block group is in the middle of
5553                  * caching and we are ok with waiting, then go ahead and wait
5554                  * for progress to be made, and set failed_alloc to true.
5555                  *
5556                  * If failed_alloc is true then we've already waited on this
5557                  * block group once and should move on to the next block group.
5558                  */
5559                 if (!offset && !failed_alloc && !cached &&
5560                     loop > LOOP_CACHING_NOWAIT) {
5561                         wait_block_group_cache_progress(block_group,
5562                                                 num_bytes + empty_size);
5563                         failed_alloc = true;
5564                         goto have_block_group;
5565                 } else if (!offset) {
5566                         if (!cached)
5567                                 have_caching_bg = true;
5568                         goto loop;
5569                 }
5570 checks:
5571                 search_start = stripe_align(root, offset);
5572                 /* move on to the next group */
5573                 if (search_start + num_bytes >= search_end) {
5574                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5575                         goto loop;
5576                 }
5577
5578                 /* move on to the next group */
5579                 if (search_start + num_bytes >
5580                     used_block_group->key.objectid + used_block_group->key.offset) {
5581                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5582                         goto loop;
5583                 }
5584
5585                 if (offset < search_start)
5586                         btrfs_add_free_space(used_block_group, offset,
5587                                              search_start - offset);
5588                 BUG_ON(offset > search_start);
5589
5590                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
5591                                                   alloc_type);
5592                 if (ret == -EAGAIN) {
5593                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5594                         goto loop;
5595                 }
5596
5597                 /* we are all good, lets return */
5598                 ins->objectid = search_start;
5599                 ins->offset = num_bytes;
5600
5601                 trace_btrfs_reserve_extent(orig_root, block_group,
5602                                            search_start, num_bytes);
5603                 if (offset < search_start)
5604                         btrfs_add_free_space(used_block_group, offset,
5605                                              search_start - offset);
5606                 BUG_ON(offset > search_start);
5607                 if (used_block_group != block_group)
5608                         btrfs_put_block_group(used_block_group);
5609                 btrfs_put_block_group(block_group);
5610                 break;
5611 loop:
5612                 failed_cluster_refill = false;
5613                 failed_alloc = false;
5614                 BUG_ON(index != get_block_group_index(block_group));
5615                 if (used_block_group != block_group)
5616                         btrfs_put_block_group(used_block_group);
5617                 btrfs_put_block_group(block_group);
5618         }
5619         up_read(&space_info->groups_sem);
5620
5621         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
5622                 goto search;
5623
5624         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5625                 goto search;
5626
5627         /*
5628          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5629          *                      caching kthreads as we move along
5630          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5631          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5632          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5633          *                      again
5634          */
5635         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5636                 index = 0;
5637                 loop++;
5638                 if (loop == LOOP_ALLOC_CHUNK) {
5639                        if (allowed_chunk_alloc) {
5640                                 ret = do_chunk_alloc(trans, root, num_bytes +
5641                                                      2 * 1024 * 1024, data,
5642                                                      CHUNK_ALLOC_LIMITED);
5643                                 allowed_chunk_alloc = 0;
5644                                 if (ret == 1)
5645                                         done_chunk_alloc = 1;
5646                         } else if (!done_chunk_alloc &&
5647                                    space_info->force_alloc ==
5648                                    CHUNK_ALLOC_NO_FORCE) {
5649                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5650                         }
5651
5652                        /*
5653                         * We didn't allocate a chunk, go ahead and drop the
5654                         * empty size and loop again.
5655                         */
5656                        if (!done_chunk_alloc)
5657                                loop = LOOP_NO_EMPTY_SIZE;
5658                 }
5659
5660                 if (loop == LOOP_NO_EMPTY_SIZE) {
5661                         empty_size = 0;
5662                         empty_cluster = 0;
5663                 }
5664
5665                 goto search;
5666         } else if (!ins->objectid) {
5667                 ret = -ENOSPC;
5668         } else if (ins->objectid) {
5669                 ret = 0;
5670         }
5671
5672         return ret;
5673 }
5674
5675 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5676                             int dump_block_groups)
5677 {
5678         struct btrfs_block_group_cache *cache;
5679         int index = 0;
5680
5681         spin_lock(&info->lock);
5682         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
5683                (unsigned long long)info->flags,
5684                (unsigned long long)(info->total_bytes - info->bytes_used -
5685                                     info->bytes_pinned - info->bytes_reserved -
5686                                     info->bytes_readonly),
5687                (info->full) ? "" : "not ");
5688         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5689                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5690                (unsigned long long)info->total_bytes,
5691                (unsigned long long)info->bytes_used,
5692                (unsigned long long)info->bytes_pinned,
5693                (unsigned long long)info->bytes_reserved,
5694                (unsigned long long)info->bytes_may_use,
5695                (unsigned long long)info->bytes_readonly);
5696         spin_unlock(&info->lock);
5697
5698         if (!dump_block_groups)
5699                 return;
5700
5701         down_read(&info->groups_sem);
5702 again:
5703         list_for_each_entry(cache, &info->block_groups[index], list) {
5704                 spin_lock(&cache->lock);
5705                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
5706                        "%llu pinned %llu reserved\n",
5707                        (unsigned long long)cache->key.objectid,
5708                        (unsigned long long)cache->key.offset,
5709                        (unsigned long long)btrfs_block_group_used(&cache->item),
5710                        (unsigned long long)cache->pinned,
5711                        (unsigned long long)cache->reserved);
5712                 btrfs_dump_free_space(cache, bytes);
5713                 spin_unlock(&cache->lock);
5714         }
5715         if (++index < BTRFS_NR_RAID_TYPES)
5716                 goto again;
5717         up_read(&info->groups_sem);
5718 }
5719
5720 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5721                          struct btrfs_root *root,
5722                          u64 num_bytes, u64 min_alloc_size,
5723                          u64 empty_size, u64 hint_byte,
5724                          u64 search_end, struct btrfs_key *ins,
5725                          u64 data)
5726 {
5727         bool final_tried = false;
5728         int ret;
5729         u64 search_start = 0;
5730
5731         data = btrfs_get_alloc_profile(root, data);
5732 again:
5733         /*
5734          * the only place that sets empty_size is btrfs_realloc_node, which
5735          * is not called recursively on allocations
5736          */
5737         if (empty_size || root->ref_cows)
5738                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5739                                      num_bytes + 2 * 1024 * 1024, data,
5740                                      CHUNK_ALLOC_NO_FORCE);
5741
5742         WARN_ON(num_bytes < root->sectorsize);
5743         ret = find_free_extent(trans, root, num_bytes, empty_size,
5744                                search_start, search_end, hint_byte,
5745                                ins, data);
5746
5747         if (ret == -ENOSPC) {
5748                 if (!final_tried) {
5749                         num_bytes = num_bytes >> 1;
5750                         num_bytes = num_bytes & ~(root->sectorsize - 1);
5751                         num_bytes = max(num_bytes, min_alloc_size);
5752                         do_chunk_alloc(trans, root->fs_info->extent_root,
5753                                        num_bytes, data, CHUNK_ALLOC_FORCE);
5754                         if (num_bytes == min_alloc_size)
5755                                 final_tried = true;
5756                         goto again;
5757                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
5758                         struct btrfs_space_info *sinfo;
5759
5760                         sinfo = __find_space_info(root->fs_info, data);
5761                         printk(KERN_ERR "btrfs allocation failed flags %llu, "
5762                                "wanted %llu\n", (unsigned long long)data,
5763                                (unsigned long long)num_bytes);
5764                         dump_space_info(sinfo, num_bytes, 1);
5765                 }
5766         }
5767
5768         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5769
5770         return ret;
5771 }
5772
5773 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
5774                                         u64 start, u64 len, int pin)
5775 {
5776         struct btrfs_block_group_cache *cache;
5777         int ret = 0;
5778
5779         cache = btrfs_lookup_block_group(root->fs_info, start);
5780         if (!cache) {
5781                 printk(KERN_ERR "Unable to find block group for %llu\n",
5782                        (unsigned long long)start);
5783                 return -ENOSPC;
5784         }
5785
5786         if (btrfs_test_opt(root, DISCARD))
5787                 ret = btrfs_discard_extent(root, start, len, NULL);
5788
5789         if (pin)
5790                 pin_down_extent(root, cache, start, len, 1);
5791         else {
5792                 btrfs_add_free_space(cache, start, len);
5793                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
5794         }
5795         btrfs_put_block_group(cache);
5796
5797         trace_btrfs_reserved_extent_free(root, start, len);
5798
5799         return ret;
5800 }
5801
5802 int btrfs_free_reserved_extent(struct btrfs_root *root,
5803                                         u64 start, u64 len)
5804 {
5805         return __btrfs_free_reserved_extent(root, start, len, 0);
5806 }
5807
5808 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
5809                                        u64 start, u64 len)
5810 {
5811         return __btrfs_free_reserved_extent(root, start, len, 1);
5812 }
5813
5814 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5815                                       struct btrfs_root *root,
5816                                       u64 parent, u64 root_objectid,
5817                                       u64 flags, u64 owner, u64 offset,
5818                                       struct btrfs_key *ins, int ref_mod)
5819 {
5820         int ret;
5821         struct btrfs_fs_info *fs_info = root->fs_info;
5822         struct btrfs_extent_item *extent_item;
5823         struct btrfs_extent_inline_ref *iref;
5824         struct btrfs_path *path;
5825         struct extent_buffer *leaf;
5826         int type;
5827         u32 size;
5828
5829         if (parent > 0)
5830                 type = BTRFS_SHARED_DATA_REF_KEY;
5831         else
5832                 type = BTRFS_EXTENT_DATA_REF_KEY;
5833
5834         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
5835
5836         path = btrfs_alloc_path();
5837         if (!path)
5838                 return -ENOMEM;
5839
5840         path->leave_spinning = 1;
5841         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5842                                       ins, size);
5843         BUG_ON(ret);
5844
5845         leaf = path->nodes[0];
5846         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5847                                      struct btrfs_extent_item);
5848         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
5849         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5850         btrfs_set_extent_flags(leaf, extent_item,
5851                                flags | BTRFS_EXTENT_FLAG_DATA);
5852
5853         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
5854         btrfs_set_extent_inline_ref_type(leaf, iref, type);
5855         if (parent > 0) {
5856                 struct btrfs_shared_data_ref *ref;
5857                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
5858                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5859                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
5860         } else {
5861                 struct btrfs_extent_data_ref *ref;
5862                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
5863                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
5864                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
5865                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
5866                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
5867         }
5868
5869         btrfs_mark_buffer_dirty(path->nodes[0]);
5870         btrfs_free_path(path);
5871
5872         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5873         if (ret) {
5874                 printk(KERN_ERR "btrfs update block group failed for %llu "
5875                        "%llu\n", (unsigned long long)ins->objectid,
5876                        (unsigned long long)ins->offset);
5877                 BUG();
5878         }
5879         return ret;
5880 }
5881
5882 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
5883                                      struct btrfs_root *root,
5884                                      u64 parent, u64 root_objectid,
5885                                      u64 flags, struct btrfs_disk_key *key,
5886                                      int level, struct btrfs_key *ins)
5887 {
5888         int ret;
5889         struct btrfs_fs_info *fs_info = root->fs_info;
5890         struct btrfs_extent_item *extent_item;
5891         struct btrfs_tree_block_info *block_info;
5892         struct btrfs_extent_inline_ref *iref;
5893         struct btrfs_path *path;
5894         struct extent_buffer *leaf;
5895         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
5896
5897         path = btrfs_alloc_path();
5898         if (!path)
5899                 return -ENOMEM;
5900
5901         path->leave_spinning = 1;
5902         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5903                                       ins, size);
5904         BUG_ON(ret);
5905
5906         leaf = path->nodes[0];
5907         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5908                                      struct btrfs_extent_item);
5909         btrfs_set_extent_refs(leaf, extent_item, 1);
5910         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5911         btrfs_set_extent_flags(leaf, extent_item,
5912                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
5913         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
5914
5915         btrfs_set_tree_block_key(leaf, block_info, key);
5916         btrfs_set_tree_block_level(leaf, block_info, level);
5917
5918         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
5919         if (parent > 0) {
5920                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
5921                 btrfs_set_extent_inline_ref_type(leaf, iref,
5922                                                  BTRFS_SHARED_BLOCK_REF_KEY);
5923                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5924         } else {
5925                 btrfs_set_extent_inline_ref_type(leaf, iref,
5926                                                  BTRFS_TREE_BLOCK_REF_KEY);
5927                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
5928         }
5929
5930         btrfs_mark_buffer_dirty(leaf);
5931         btrfs_free_path(path);
5932
5933         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5934         if (ret) {
5935                 printk(KERN_ERR "btrfs update block group failed for %llu "
5936                        "%llu\n", (unsigned long long)ins->objectid,
5937                        (unsigned long long)ins->offset);
5938                 BUG();
5939         }
5940         return ret;
5941 }
5942
5943 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5944                                      struct btrfs_root *root,
5945                                      u64 root_objectid, u64 owner,
5946                                      u64 offset, struct btrfs_key *ins)
5947 {
5948         int ret;
5949
5950         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
5951
5952         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
5953                                          ins->offset, 0,
5954                                          root_objectid, owner, offset,
5955                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
5956         return ret;
5957 }
5958
5959 /*
5960  * this is used by the tree logging recovery code.  It records that
5961  * an extent has been allocated and makes sure to clear the free
5962  * space cache bits as well
5963  */
5964 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
5965                                    struct btrfs_root *root,
5966                                    u64 root_objectid, u64 owner, u64 offset,
5967                                    struct btrfs_key *ins)
5968 {
5969         int ret;
5970         struct btrfs_block_group_cache *block_group;
5971         struct btrfs_caching_control *caching_ctl;
5972         u64 start = ins->objectid;
5973         u64 num_bytes = ins->offset;
5974
5975         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
5976         cache_block_group(block_group, trans, NULL, 0);
5977         caching_ctl = get_caching_control(block_group);
5978
5979         if (!caching_ctl) {
5980                 BUG_ON(!block_group_cache_done(block_group));
5981                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5982                 BUG_ON(ret);
5983         } else {
5984                 mutex_lock(&caching_ctl->mutex);
5985
5986                 if (start >= caching_ctl->progress) {
5987                         ret = add_excluded_extent(root, start, num_bytes);
5988                         BUG_ON(ret);
5989                 } else if (start + num_bytes <= caching_ctl->progress) {
5990                         ret = btrfs_remove_free_space(block_group,
5991                                                       start, num_bytes);
5992                         BUG_ON(ret);
5993                 } else {
5994                         num_bytes = caching_ctl->progress - start;
5995                         ret = btrfs_remove_free_space(block_group,
5996                                                       start, num_bytes);
5997                         BUG_ON(ret);
5998
5999                         start = caching_ctl->progress;
6000                         num_bytes = ins->objectid + ins->offset -
6001                                     caching_ctl->progress;
6002                         ret = add_excluded_extent(root, start, num_bytes);
6003                         BUG_ON(ret);
6004                 }
6005
6006                 mutex_unlock(&caching_ctl->mutex);
6007                 put_caching_control(caching_ctl);
6008         }
6009
6010         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6011                                           RESERVE_ALLOC_NO_ACCOUNT);
6012         BUG_ON(ret);
6013         btrfs_put_block_group(block_group);
6014         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6015                                          0, owner, offset, ins, 1);
6016         return ret;
6017 }
6018
6019 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
6020                                             struct btrfs_root *root,
6021                                             u64 bytenr, u32 blocksize,
6022                                             int level)
6023 {
6024         struct extent_buffer *buf;
6025
6026         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6027         if (!buf)
6028                 return ERR_PTR(-ENOMEM);
6029         btrfs_set_header_generation(buf, trans->transid);
6030         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6031         btrfs_tree_lock(buf);
6032         clean_tree_block(trans, root, buf);
6033
6034         btrfs_set_lock_blocking(buf);
6035         btrfs_set_buffer_uptodate(buf);
6036
6037         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6038                 /*
6039                  * we allow two log transactions at a time, use different
6040                  * EXENT bit to differentiate dirty pages.
6041                  */
6042                 if (root->log_transid % 2 == 0)
6043                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6044                                         buf->start + buf->len - 1, GFP_NOFS);
6045                 else
6046                         set_extent_new(&root->dirty_log_pages, buf->start,
6047                                         buf->start + buf->len - 1, GFP_NOFS);
6048         } else {
6049                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6050                          buf->start + buf->len - 1, GFP_NOFS);
6051         }
6052         trans->blocks_used++;
6053         /* this returns a buffer locked for blocking */
6054         return buf;
6055 }
6056
6057 static struct btrfs_block_rsv *
6058 use_block_rsv(struct btrfs_trans_handle *trans,
6059               struct btrfs_root *root, u32 blocksize)
6060 {
6061         struct btrfs_block_rsv *block_rsv;
6062         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6063         int ret;
6064
6065         block_rsv = get_block_rsv(trans, root);
6066
6067         if (block_rsv->size == 0) {
6068                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6069                 /*
6070                  * If we couldn't reserve metadata bytes try and use some from
6071                  * the global reserve.
6072                  */
6073                 if (ret && block_rsv != global_rsv) {
6074                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6075                         if (!ret)
6076                                 return global_rsv;
6077                         return ERR_PTR(ret);
6078                 } else if (ret) {
6079                         return ERR_PTR(ret);
6080                 }
6081                 return block_rsv;
6082         }
6083
6084         ret = block_rsv_use_bytes(block_rsv, blocksize);
6085         if (!ret)
6086                 return block_rsv;
6087         if (ret) {
6088                 static DEFINE_RATELIMIT_STATE(_rs,
6089                                 DEFAULT_RATELIMIT_INTERVAL,
6090                                 /*DEFAULT_RATELIMIT_BURST*/ 2);
6091                 if (__ratelimit(&_rs)) {
6092                         printk(KERN_DEBUG "btrfs: block rsv returned %d\n", ret);
6093                         WARN_ON(1);
6094                 }
6095                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6096                 if (!ret) {
6097                         return block_rsv;
6098                 } else if (ret && block_rsv != global_rsv) {
6099                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6100                         if (!ret)
6101                                 return global_rsv;
6102                 }
6103         }
6104
6105         return ERR_PTR(-ENOSPC);
6106 }
6107
6108 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6109                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6110 {
6111         block_rsv_add_bytes(block_rsv, blocksize, 0);
6112         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6113 }
6114
6115 /*
6116  * finds a free extent and does all the dirty work required for allocation
6117  * returns the key for the extent through ins, and a tree buffer for
6118  * the first block of the extent through buf.
6119  *
6120  * returns the tree buffer or NULL.
6121  */
6122 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6123                                         struct btrfs_root *root, u32 blocksize,
6124                                         u64 parent, u64 root_objectid,
6125                                         struct btrfs_disk_key *key, int level,
6126                                         u64 hint, u64 empty_size, int for_cow)
6127 {
6128         struct btrfs_key ins;
6129         struct btrfs_block_rsv *block_rsv;
6130         struct extent_buffer *buf;
6131         u64 flags = 0;
6132         int ret;
6133
6134
6135         block_rsv = use_block_rsv(trans, root, blocksize);
6136         if (IS_ERR(block_rsv))
6137                 return ERR_CAST(block_rsv);
6138
6139         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6140                                    empty_size, hint, (u64)-1, &ins, 0);
6141         if (ret) {
6142                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6143                 return ERR_PTR(ret);
6144         }
6145
6146         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6147                                     blocksize, level);
6148         BUG_ON(IS_ERR(buf));
6149
6150         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6151                 if (parent == 0)
6152                         parent = ins.objectid;
6153                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6154         } else
6155                 BUG_ON(parent > 0);
6156
6157         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6158                 struct btrfs_delayed_extent_op *extent_op;
6159                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
6160                 BUG_ON(!extent_op);
6161                 if (key)
6162                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6163                 else
6164                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6165                 extent_op->flags_to_set = flags;
6166                 extent_op->update_key = 1;
6167                 extent_op->update_flags = 1;
6168                 extent_op->is_data = 0;
6169
6170                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6171                                         ins.objectid,
6172                                         ins.offset, parent, root_objectid,
6173                                         level, BTRFS_ADD_DELAYED_EXTENT,
6174                                         extent_op, for_cow);
6175                 BUG_ON(ret);
6176         }
6177         return buf;
6178 }
6179
6180 struct walk_control {
6181         u64 refs[BTRFS_MAX_LEVEL];
6182         u64 flags[BTRFS_MAX_LEVEL];
6183         struct btrfs_key update_progress;
6184         int stage;
6185         int level;
6186         int shared_level;
6187         int update_ref;
6188         int keep_locks;
6189         int reada_slot;
6190         int reada_count;
6191         int for_reloc;
6192 };
6193
6194 #define DROP_REFERENCE  1
6195 #define UPDATE_BACKREF  2
6196
6197 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6198                                      struct btrfs_root *root,
6199                                      struct walk_control *wc,
6200                                      struct btrfs_path *path)
6201 {
6202         u64 bytenr;
6203         u64 generation;
6204         u64 refs;
6205         u64 flags;
6206         u32 nritems;
6207         u32 blocksize;
6208         struct btrfs_key key;
6209         struct extent_buffer *eb;
6210         int ret;
6211         int slot;
6212         int nread = 0;
6213
6214         if (path->slots[wc->level] < wc->reada_slot) {
6215                 wc->reada_count = wc->reada_count * 2 / 3;
6216                 wc->reada_count = max(wc->reada_count, 2);
6217         } else {
6218                 wc->reada_count = wc->reada_count * 3 / 2;
6219                 wc->reada_count = min_t(int, wc->reada_count,
6220                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6221         }
6222
6223         eb = path->nodes[wc->level];
6224         nritems = btrfs_header_nritems(eb);
6225         blocksize = btrfs_level_size(root, wc->level - 1);
6226
6227         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6228                 if (nread >= wc->reada_count)
6229                         break;
6230
6231                 cond_resched();
6232                 bytenr = btrfs_node_blockptr(eb, slot);
6233                 generation = btrfs_node_ptr_generation(eb, slot);
6234
6235                 if (slot == path->slots[wc->level])
6236                         goto reada;
6237
6238                 if (wc->stage == UPDATE_BACKREF &&
6239                     generation <= root->root_key.offset)
6240                         continue;
6241
6242                 /* We don't lock the tree block, it's OK to be racy here */
6243                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6244                                                &refs, &flags);
6245                 BUG_ON(ret);
6246                 BUG_ON(refs == 0);
6247
6248                 if (wc->stage == DROP_REFERENCE) {
6249                         if (refs == 1)
6250                                 goto reada;
6251
6252                         if (wc->level == 1 &&
6253                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6254                                 continue;
6255                         if (!wc->update_ref ||
6256                             generation <= root->root_key.offset)
6257                                 continue;
6258                         btrfs_node_key_to_cpu(eb, &key, slot);
6259                         ret = btrfs_comp_cpu_keys(&key,
6260                                                   &wc->update_progress);
6261                         if (ret < 0)
6262                                 continue;
6263                 } else {
6264                         if (wc->level == 1 &&
6265                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6266                                 continue;
6267                 }
6268 reada:
6269                 ret = readahead_tree_block(root, bytenr, blocksize,
6270                                            generation);
6271                 if (ret)
6272                         break;
6273                 nread++;
6274         }
6275         wc->reada_slot = slot;
6276 }
6277
6278 /*
6279  * hepler to process tree block while walking down the tree.
6280  *
6281  * when wc->stage == UPDATE_BACKREF, this function updates
6282  * back refs for pointers in the block.
6283  *
6284  * NOTE: return value 1 means we should stop walking down.
6285  */
6286 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
6287                                    struct btrfs_root *root,
6288                                    struct btrfs_path *path,
6289                                    struct walk_control *wc, int lookup_info)
6290 {
6291         int level = wc->level;
6292         struct extent_buffer *eb = path->nodes[level];
6293         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6294         int ret;
6295
6296         if (wc->stage == UPDATE_BACKREF &&
6297             btrfs_header_owner(eb) != root->root_key.objectid)
6298                 return 1;
6299
6300         /*
6301          * when reference count of tree block is 1, it won't increase
6302          * again. once full backref flag is set, we never clear it.
6303          */
6304         if (lookup_info &&
6305             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
6306              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
6307                 BUG_ON(!path->locks[level]);
6308                 ret = btrfs_lookup_extent_info(trans, root,
6309                                                eb->start, eb->len,
6310                                                &wc->refs[level],
6311                                                &wc->flags[level]);
6312                 BUG_ON(ret);
6313                 BUG_ON(wc->refs[level] == 0);
6314         }
6315
6316         if (wc->stage == DROP_REFERENCE) {
6317                 if (wc->refs[level] > 1)
6318                         return 1;
6319
6320                 if (path->locks[level] && !wc->keep_locks) {
6321                         btrfs_tree_unlock_rw(eb, path->locks[level]);
6322                         path->locks[level] = 0;
6323                 }
6324                 return 0;
6325         }
6326
6327         /* wc->stage == UPDATE_BACKREF */
6328         if (!(wc->flags[level] & flag)) {
6329                 BUG_ON(!path->locks[level]);
6330                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
6331                 BUG_ON(ret);
6332                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
6333                 BUG_ON(ret);
6334                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
6335                                                   eb->len, flag, 0);
6336                 BUG_ON(ret);
6337                 wc->flags[level] |= flag;
6338         }
6339
6340         /*
6341          * the block is shared by multiple trees, so it's not good to
6342          * keep the tree lock
6343          */
6344         if (path->locks[level] && level > 0) {
6345                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6346                 path->locks[level] = 0;
6347         }
6348         return 0;
6349 }
6350
6351 /*
6352  * hepler to process tree block pointer.
6353  *
6354  * when wc->stage == DROP_REFERENCE, this function checks
6355  * reference count of the block pointed to. if the block
6356  * is shared and we need update back refs for the subtree
6357  * rooted at the block, this function changes wc->stage to
6358  * UPDATE_BACKREF. if the block is shared and there is no
6359  * need to update back, this function drops the reference
6360  * to the block.
6361  *
6362  * NOTE: return value 1 means we should stop walking down.
6363  */
6364 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
6365                                  struct btrfs_root *root,
6366                                  struct btrfs_path *path,
6367                                  struct walk_control *wc, int *lookup_info)
6368 {
6369         u64 bytenr;
6370         u64 generation;
6371         u64 parent;
6372         u32 blocksize;
6373         struct btrfs_key key;
6374         struct extent_buffer *next;
6375         int level = wc->level;
6376         int reada = 0;
6377         int ret = 0;
6378
6379         generation = btrfs_node_ptr_generation(path->nodes[level],
6380                                                path->slots[level]);
6381         /*
6382          * if the lower level block was created before the snapshot
6383          * was created, we know there is no need to update back refs
6384          * for the subtree
6385          */
6386         if (wc->stage == UPDATE_BACKREF &&
6387             generation <= root->root_key.offset) {
6388                 *lookup_info = 1;
6389                 return 1;
6390         }
6391
6392         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6393         blocksize = btrfs_level_size(root, level - 1);
6394
6395         next = btrfs_find_tree_block(root, bytenr, blocksize);
6396         if (!next) {
6397                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6398                 if (!next)
6399                         return -ENOMEM;
6400                 reada = 1;
6401         }
6402         btrfs_tree_lock(next);
6403         btrfs_set_lock_blocking(next);
6404
6405         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6406                                        &wc->refs[level - 1],
6407                                        &wc->flags[level - 1]);
6408         BUG_ON(ret);
6409         BUG_ON(wc->refs[level - 1] == 0);
6410         *lookup_info = 0;
6411
6412         if (wc->stage == DROP_REFERENCE) {
6413                 if (wc->refs[level - 1] > 1) {
6414                         if (level == 1 &&
6415                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6416                                 goto skip;
6417
6418                         if (!wc->update_ref ||
6419                             generation <= root->root_key.offset)
6420                                 goto skip;
6421
6422                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6423                                               path->slots[level]);
6424                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6425                         if (ret < 0)
6426                                 goto skip;
6427
6428                         wc->stage = UPDATE_BACKREF;
6429                         wc->shared_level = level - 1;
6430                 }
6431         } else {
6432                 if (level == 1 &&
6433                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6434                         goto skip;
6435         }
6436
6437         if (!btrfs_buffer_uptodate(next, generation)) {
6438                 btrfs_tree_unlock(next);
6439                 free_extent_buffer(next);
6440                 next = NULL;
6441                 *lookup_info = 1;
6442         }
6443
6444         if (!next) {
6445                 if (reada && level == 1)
6446                         reada_walk_down(trans, root, wc, path);
6447                 next = read_tree_block(root, bytenr, blocksize, generation);
6448                 if (!next)
6449                         return -EIO;
6450                 btrfs_tree_lock(next);
6451                 btrfs_set_lock_blocking(next);
6452         }
6453
6454         level--;
6455         BUG_ON(level != btrfs_header_level(next));
6456         path->nodes[level] = next;
6457         path->slots[level] = 0;
6458         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6459         wc->level = level;
6460         if (wc->level == 1)
6461                 wc->reada_slot = 0;
6462         return 0;
6463 skip:
6464         wc->refs[level - 1] = 0;
6465         wc->flags[level - 1] = 0;
6466         if (wc->stage == DROP_REFERENCE) {
6467                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6468                         parent = path->nodes[level]->start;
6469                 } else {
6470                         BUG_ON(root->root_key.objectid !=
6471                                btrfs_header_owner(path->nodes[level]));
6472                         parent = 0;
6473                 }
6474
6475                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6476                                 root->root_key.objectid, level - 1, 0, 0);
6477                 BUG_ON(ret);
6478         }
6479         btrfs_tree_unlock(next);
6480         free_extent_buffer(next);
6481         *lookup_info = 1;
6482         return 1;
6483 }
6484
6485 /*
6486  * hepler to process tree block while walking up the tree.
6487  *
6488  * when wc->stage == DROP_REFERENCE, this function drops
6489  * reference count on the block.
6490  *
6491  * when wc->stage == UPDATE_BACKREF, this function changes
6492  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6493  * to UPDATE_BACKREF previously while processing the block.
6494  *
6495  * NOTE: return value 1 means we should stop walking up.
6496  */
6497 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6498                                  struct btrfs_root *root,
6499                                  struct btrfs_path *path,
6500                                  struct walk_control *wc)
6501 {
6502         int ret;
6503         int level = wc->level;
6504         struct extent_buffer *eb = path->nodes[level];
6505         u64 parent = 0;
6506
6507         if (wc->stage == UPDATE_BACKREF) {
6508                 BUG_ON(wc->shared_level < level);
6509                 if (level < wc->shared_level)
6510                         goto out;
6511
6512                 ret = find_next_key(path, level + 1, &wc->update_progress);
6513                 if (ret > 0)
6514                         wc->update_ref = 0;
6515
6516                 wc->stage = DROP_REFERENCE;
6517                 wc->shared_level = -1;
6518                 path->slots[level] = 0;
6519
6520                 /*
6521                  * check reference count again if the block isn't locked.
6522                  * we should start walking down the tree again if reference
6523                  * count is one.
6524                  */
6525                 if (!path->locks[level]) {
6526                         BUG_ON(level == 0);
6527                         btrfs_tree_lock(eb);
6528                         btrfs_set_lock_blocking(eb);
6529                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6530
6531                         ret = btrfs_lookup_extent_info(trans, root,
6532                                                        eb->start, eb->len,
6533                                                        &wc->refs[level],
6534                                                        &wc->flags[level]);
6535                         BUG_ON(ret);
6536                         BUG_ON(wc->refs[level] == 0);
6537                         if (wc->refs[level] == 1) {
6538                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6539                                 return 1;
6540                         }
6541                 }
6542         }
6543
6544         /* wc->stage == DROP_REFERENCE */
6545         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6546
6547         if (wc->refs[level] == 1) {
6548                 if (level == 0) {
6549                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6550                                 ret = btrfs_dec_ref(trans, root, eb, 1,
6551                                                     wc->for_reloc);
6552                         else
6553                                 ret = btrfs_dec_ref(trans, root, eb, 0,
6554                                                     wc->for_reloc);
6555                         BUG_ON(ret);
6556                 }
6557                 /* make block locked assertion in clean_tree_block happy */
6558                 if (!path->locks[level] &&
6559                     btrfs_header_generation(eb) == trans->transid) {
6560                         btrfs_tree_lock(eb);
6561                         btrfs_set_lock_blocking(eb);
6562                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6563                 }
6564                 clean_tree_block(trans, root, eb);
6565         }
6566
6567         if (eb == root->node) {
6568                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6569                         parent = eb->start;
6570                 else
6571                         BUG_ON(root->root_key.objectid !=
6572                                btrfs_header_owner(eb));
6573         } else {
6574                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6575                         parent = path->nodes[level + 1]->start;
6576                 else
6577                         BUG_ON(root->root_key.objectid !=
6578                                btrfs_header_owner(path->nodes[level + 1]));
6579         }
6580
6581         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1, 0);
6582 out:
6583         wc->refs[level] = 0;
6584         wc->flags[level] = 0;
6585         return 0;
6586 }
6587
6588 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6589                                    struct btrfs_root *root,
6590                                    struct btrfs_path *path,
6591                                    struct walk_control *wc)
6592 {
6593         int level = wc->level;
6594         int lookup_info = 1;
6595         int ret;
6596
6597         while (level >= 0) {
6598                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6599                 if (ret > 0)
6600                         break;
6601
6602                 if (level == 0)
6603                         break;
6604
6605                 if (path->slots[level] >=
6606                     btrfs_header_nritems(path->nodes[level]))
6607                         break;
6608
6609                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6610                 if (ret > 0) {
6611                         path->slots[level]++;
6612                         continue;
6613                 } else if (ret < 0)
6614                         return ret;
6615                 level = wc->level;
6616         }
6617         return 0;
6618 }
6619
6620 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6621                                  struct btrfs_root *root,
6622                                  struct btrfs_path *path,
6623                                  struct walk_control *wc, int max_level)
6624 {
6625         int level = wc->level;
6626         int ret;
6627
6628         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6629         while (level < max_level && path->nodes[level]) {
6630                 wc->level = level;
6631                 if (path->slots[level] + 1 <
6632                     btrfs_header_nritems(path->nodes[level])) {
6633                         path->slots[level]++;
6634                         return 0;
6635                 } else {
6636                         ret = walk_up_proc(trans, root, path, wc);
6637                         if (ret > 0)
6638                                 return 0;
6639
6640                         if (path->locks[level]) {
6641                                 btrfs_tree_unlock_rw(path->nodes[level],
6642                                                      path->locks[level]);
6643                                 path->locks[level] = 0;
6644                         }
6645                         free_extent_buffer(path->nodes[level]);
6646                         path->nodes[level] = NULL;
6647                         level++;
6648                 }
6649         }
6650         return 1;
6651 }
6652
6653 /*
6654  * drop a subvolume tree.
6655  *
6656  * this function traverses the tree freeing any blocks that only
6657  * referenced by the tree.
6658  *
6659  * when a shared tree block is found. this function decreases its
6660  * reference count by one. if update_ref is true, this function
6661  * also make sure backrefs for the shared block and all lower level
6662  * blocks are properly updated.
6663  */
6664 void btrfs_drop_snapshot(struct btrfs_root *root,
6665                          struct btrfs_block_rsv *block_rsv, int update_ref,
6666                          int for_reloc)
6667 {
6668         struct btrfs_path *path;
6669         struct btrfs_trans_handle *trans;
6670         struct btrfs_root *tree_root = root->fs_info->tree_root;
6671         struct btrfs_root_item *root_item = &root->root_item;
6672         struct walk_control *wc;
6673         struct btrfs_key key;
6674         int err = 0;
6675         int ret;
6676         int level;
6677
6678         path = btrfs_alloc_path();
6679         if (!path) {
6680                 err = -ENOMEM;
6681                 goto out;
6682         }
6683
6684         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6685         if (!wc) {
6686                 btrfs_free_path(path);
6687                 err = -ENOMEM;
6688                 goto out;
6689         }
6690
6691         trans = btrfs_start_transaction(tree_root, 0);
6692         BUG_ON(IS_ERR(trans));
6693
6694         if (block_rsv)
6695                 trans->block_rsv = block_rsv;
6696
6697         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6698                 level = btrfs_header_level(root->node);
6699                 path->nodes[level] = btrfs_lock_root_node(root);
6700                 btrfs_set_lock_blocking(path->nodes[level]);
6701                 path->slots[level] = 0;
6702                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6703                 memset(&wc->update_progress, 0,
6704                        sizeof(wc->update_progress));
6705         } else {
6706                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6707                 memcpy(&wc->update_progress, &key,
6708                        sizeof(wc->update_progress));
6709
6710                 level = root_item->drop_level;
6711                 BUG_ON(level == 0);
6712                 path->lowest_level = level;
6713                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6714                 path->lowest_level = 0;
6715                 if (ret < 0) {
6716                         err = ret;
6717                         goto out_free;
6718                 }
6719                 WARN_ON(ret > 0);
6720
6721                 /*
6722                  * unlock our path, this is safe because only this
6723                  * function is allowed to delete this snapshot
6724                  */
6725                 btrfs_unlock_up_safe(path, 0);
6726
6727                 level = btrfs_header_level(root->node);
6728                 while (1) {
6729                         btrfs_tree_lock(path->nodes[level]);
6730                         btrfs_set_lock_blocking(path->nodes[level]);
6731
6732                         ret = btrfs_lookup_extent_info(trans, root,
6733                                                 path->nodes[level]->start,
6734                                                 path->nodes[level]->len,
6735                                                 &wc->refs[level],
6736                                                 &wc->flags[level]);
6737                         BUG_ON(ret);
6738                         BUG_ON(wc->refs[level] == 0);
6739
6740                         if (level == root_item->drop_level)
6741                                 break;
6742
6743                         btrfs_tree_unlock(path->nodes[level]);
6744                         WARN_ON(wc->refs[level] != 1);
6745                         level--;
6746                 }
6747         }
6748
6749         wc->level = level;
6750         wc->shared_level = -1;
6751         wc->stage = DROP_REFERENCE;
6752         wc->update_ref = update_ref;
6753         wc->keep_locks = 0;
6754         wc->for_reloc = for_reloc;
6755         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6756
6757         while (1) {
6758                 ret = walk_down_tree(trans, root, path, wc);
6759                 if (ret < 0) {
6760                         err = ret;
6761                         break;
6762                 }
6763
6764                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
6765                 if (ret < 0) {
6766                         err = ret;
6767                         break;
6768                 }
6769
6770                 if (ret > 0) {
6771                         BUG_ON(wc->stage != DROP_REFERENCE);
6772                         break;
6773                 }
6774
6775                 if (wc->stage == DROP_REFERENCE) {
6776                         level = wc->level;
6777                         btrfs_node_key(path->nodes[level],
6778                                        &root_item->drop_progress,
6779                                        path->slots[level]);
6780                         root_item->drop_level = level;
6781                 }
6782
6783                 BUG_ON(wc->level == 0);
6784                 if (btrfs_should_end_transaction(trans, tree_root)) {
6785                         ret = btrfs_update_root(trans, tree_root,
6786                                                 &root->root_key,
6787                                                 root_item);
6788                         BUG_ON(ret);
6789
6790                         btrfs_end_transaction_throttle(trans, tree_root);
6791                         trans = btrfs_start_transaction(tree_root, 0);
6792                         BUG_ON(IS_ERR(trans));
6793                         if (block_rsv)
6794                                 trans->block_rsv = block_rsv;
6795                 }
6796         }
6797         btrfs_release_path(path);
6798         BUG_ON(err);
6799
6800         ret = btrfs_del_root(trans, tree_root, &root->root_key);
6801         BUG_ON(ret);
6802
6803         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
6804                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
6805                                            NULL, NULL);
6806                 BUG_ON(ret < 0);
6807                 if (ret > 0) {
6808                         /* if we fail to delete the orphan item this time
6809                          * around, it'll get picked up the next time.
6810                          *
6811                          * The most common failure here is just -ENOENT.
6812                          */
6813                         btrfs_del_orphan_item(trans, tree_root,
6814                                               root->root_key.objectid);
6815                 }
6816         }
6817
6818         if (root->in_radix) {
6819                 btrfs_free_fs_root(tree_root->fs_info, root);
6820         } else {
6821                 free_extent_buffer(root->node);
6822                 free_extent_buffer(root->commit_root);
6823                 kfree(root);
6824         }
6825 out_free:
6826         btrfs_end_transaction_throttle(trans, tree_root);
6827         kfree(wc);
6828         btrfs_free_path(path);
6829 out:
6830         if (err)
6831                 btrfs_std_error(root->fs_info, err);
6832         return;
6833 }
6834
6835 /*
6836  * drop subtree rooted at tree block 'node'.
6837  *
6838  * NOTE: this function will unlock and release tree block 'node'
6839  * only used by relocation code
6840  */
6841 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6842                         struct btrfs_root *root,
6843                         struct extent_buffer *node,
6844                         struct extent_buffer *parent)
6845 {
6846         struct btrfs_path *path;
6847         struct walk_control *wc;
6848         int level;
6849         int parent_level;
6850         int ret = 0;
6851         int wret;
6852
6853         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6854
6855         path = btrfs_alloc_path();
6856         if (!path)
6857                 return -ENOMEM;
6858
6859         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6860         if (!wc) {
6861                 btrfs_free_path(path);
6862                 return -ENOMEM;
6863         }
6864
6865         btrfs_assert_tree_locked(parent);
6866         parent_level = btrfs_header_level(parent);
6867         extent_buffer_get(parent);
6868         path->nodes[parent_level] = parent;
6869         path->slots[parent_level] = btrfs_header_nritems(parent);
6870
6871         btrfs_assert_tree_locked(node);
6872         level = btrfs_header_level(node);
6873         path->nodes[level] = node;
6874         path->slots[level] = 0;
6875         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6876
6877         wc->refs[parent_level] = 1;
6878         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6879         wc->level = level;
6880         wc->shared_level = -1;
6881         wc->stage = DROP_REFERENCE;
6882         wc->update_ref = 0;
6883         wc->keep_locks = 1;
6884         wc->for_reloc = 1;
6885         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6886
6887         while (1) {
6888                 wret = walk_down_tree(trans, root, path, wc);
6889                 if (wret < 0) {
6890                         ret = wret;
6891                         break;
6892                 }
6893
6894                 wret = walk_up_tree(trans, root, path, wc, parent_level);
6895                 if (wret < 0)
6896                         ret = wret;
6897                 if (wret != 0)
6898                         break;
6899         }
6900
6901         kfree(wc);
6902         btrfs_free_path(path);
6903         return ret;
6904 }
6905
6906 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
6907 {
6908         u64 num_devices;
6909         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
6910                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
6911
6912         if (root->fs_info->balance_ctl) {
6913                 struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
6914                 u64 tgt = 0;
6915
6916                 /* pick restriper's target profile and return */
6917                 if (flags & BTRFS_BLOCK_GROUP_DATA &&
6918                     bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
6919                         tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
6920                 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
6921                            bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
6922                         tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
6923                 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
6924                            bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
6925                         tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
6926                 }
6927
6928                 if (tgt) {
6929                         /* extended -> chunk profile */
6930                         tgt &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
6931                         return tgt;
6932                 }
6933         }
6934
6935         /*
6936          * we add in the count of missing devices because we want
6937          * to make sure that any RAID levels on a degraded FS
6938          * continue to be honored.
6939          */
6940         num_devices = root->fs_info->fs_devices->rw_devices +
6941                 root->fs_info->fs_devices->missing_devices;
6942
6943         if (num_devices == 1) {
6944                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6945                 stripped = flags & ~stripped;
6946
6947                 /* turn raid0 into single device chunks */
6948                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
6949                         return stripped;
6950
6951                 /* turn mirroring into duplication */
6952                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
6953                              BTRFS_BLOCK_GROUP_RAID10))
6954                         return stripped | BTRFS_BLOCK_GROUP_DUP;
6955                 return flags;
6956         } else {
6957                 /* they already had raid on here, just return */
6958                 if (flags & stripped)
6959                         return flags;
6960
6961                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6962                 stripped = flags & ~stripped;
6963
6964                 /* switch duplicated blocks with raid1 */
6965                 if (flags & BTRFS_BLOCK_GROUP_DUP)
6966                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
6967
6968                 /* turn single device chunks into raid0 */
6969                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
6970         }
6971         return flags;
6972 }
6973
6974 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
6975 {
6976         struct btrfs_space_info *sinfo = cache->space_info;
6977         u64 num_bytes;
6978         u64 min_allocable_bytes;
6979         int ret = -ENOSPC;
6980
6981
6982         /*
6983          * We need some metadata space and system metadata space for
6984          * allocating chunks in some corner cases until we force to set
6985          * it to be readonly.
6986          */
6987         if ((sinfo->flags &
6988              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
6989             !force)
6990                 min_allocable_bytes = 1 * 1024 * 1024;
6991         else
6992                 min_allocable_bytes = 0;
6993
6994         spin_lock(&sinfo->lock);
6995         spin_lock(&cache->lock);
6996
6997         if (cache->ro) {
6998                 ret = 0;
6999                 goto out;
7000         }
7001
7002         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7003                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7004
7005         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7006             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7007             min_allocable_bytes <= sinfo->total_bytes) {
7008                 sinfo->bytes_readonly += num_bytes;
7009                 cache->ro = 1;
7010                 ret = 0;
7011         }
7012 out:
7013         spin_unlock(&cache->lock);
7014         spin_unlock(&sinfo->lock);
7015         return ret;
7016 }
7017
7018 int btrfs_set_block_group_ro(struct btrfs_root *root,
7019                              struct btrfs_block_group_cache *cache)
7020
7021 {
7022         struct btrfs_trans_handle *trans;
7023         u64 alloc_flags;
7024         int ret;
7025
7026         BUG_ON(cache->ro);
7027
7028         trans = btrfs_join_transaction(root);
7029         BUG_ON(IS_ERR(trans));
7030
7031         alloc_flags = update_block_group_flags(root, cache->flags);
7032         if (alloc_flags != cache->flags)
7033                 do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7034                                CHUNK_ALLOC_FORCE);
7035
7036         ret = set_block_group_ro(cache, 0);
7037         if (!ret)
7038                 goto out;
7039         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7040         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7041                              CHUNK_ALLOC_FORCE);
7042         if (ret < 0)
7043                 goto out;
7044         ret = set_block_group_ro(cache, 0);
7045 out:
7046         btrfs_end_transaction(trans, root);
7047         return ret;
7048 }
7049
7050 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7051                             struct btrfs_root *root, u64 type)
7052 {
7053         u64 alloc_flags = get_alloc_profile(root, type);
7054         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7055                               CHUNK_ALLOC_FORCE);
7056 }
7057
7058 /*
7059  * helper to account the unused space of all the readonly block group in the
7060  * list. takes mirrors into account.
7061  */
7062 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7063 {
7064         struct btrfs_block_group_cache *block_group;
7065         u64 free_bytes = 0;
7066         int factor;
7067
7068         list_for_each_entry(block_group, groups_list, list) {
7069                 spin_lock(&block_group->lock);
7070
7071                 if (!block_group->ro) {
7072                         spin_unlock(&block_group->lock);
7073                         continue;
7074                 }
7075
7076                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7077                                           BTRFS_BLOCK_GROUP_RAID10 |
7078                                           BTRFS_BLOCK_GROUP_DUP))
7079                         factor = 2;
7080                 else
7081                         factor = 1;
7082
7083                 free_bytes += (block_group->key.offset -
7084                                btrfs_block_group_used(&block_group->item)) *
7085                                factor;
7086
7087                 spin_unlock(&block_group->lock);
7088         }
7089
7090         return free_bytes;
7091 }
7092
7093 /*
7094  * helper to account the unused space of all the readonly block group in the
7095  * space_info. takes mirrors into account.
7096  */
7097 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7098 {
7099         int i;
7100         u64 free_bytes = 0;
7101
7102         spin_lock(&sinfo->lock);
7103
7104         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7105                 if (!list_empty(&sinfo->block_groups[i]))
7106                         free_bytes += __btrfs_get_ro_block_group_free_space(
7107                                                 &sinfo->block_groups[i]);
7108
7109         spin_unlock(&sinfo->lock);
7110
7111         return free_bytes;
7112 }
7113
7114 int btrfs_set_block_group_rw(struct btrfs_root *root,
7115                               struct btrfs_block_group_cache *cache)
7116 {
7117         struct btrfs_space_info *sinfo = cache->space_info;
7118         u64 num_bytes;
7119
7120         BUG_ON(!cache->ro);
7121
7122         spin_lock(&sinfo->lock);
7123         spin_lock(&cache->lock);
7124         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7125                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7126         sinfo->bytes_readonly -= num_bytes;
7127         cache->ro = 0;
7128         spin_unlock(&cache->lock);
7129         spin_unlock(&sinfo->lock);
7130         return 0;
7131 }
7132
7133 /*
7134  * checks to see if its even possible to relocate this block group.
7135  *
7136  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7137  * ok to go ahead and try.
7138  */
7139 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7140 {
7141         struct btrfs_block_group_cache *block_group;
7142         struct btrfs_space_info *space_info;
7143         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7144         struct btrfs_device *device;
7145         u64 min_free;
7146         u64 dev_min = 1;
7147         u64 dev_nr = 0;
7148         int index;
7149         int full = 0;
7150         int ret = 0;
7151
7152         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7153
7154         /* odd, couldn't find the block group, leave it alone */
7155         if (!block_group)
7156                 return -1;
7157
7158         min_free = btrfs_block_group_used(&block_group->item);
7159
7160         /* no bytes used, we're good */
7161         if (!min_free)
7162                 goto out;
7163
7164         space_info = block_group->space_info;
7165         spin_lock(&space_info->lock);
7166
7167         full = space_info->full;
7168
7169         /*
7170          * if this is the last block group we have in this space, we can't
7171          * relocate it unless we're able to allocate a new chunk below.
7172          *
7173          * Otherwise, we need to make sure we have room in the space to handle
7174          * all of the extents from this block group.  If we can, we're good
7175          */
7176         if ((space_info->total_bytes != block_group->key.offset) &&
7177             (space_info->bytes_used + space_info->bytes_reserved +
7178              space_info->bytes_pinned + space_info->bytes_readonly +
7179              min_free < space_info->total_bytes)) {
7180                 spin_unlock(&space_info->lock);
7181                 goto out;
7182         }
7183         spin_unlock(&space_info->lock);
7184
7185         /*
7186          * ok we don't have enough space, but maybe we have free space on our
7187          * devices to allocate new chunks for relocation, so loop through our
7188          * alloc devices and guess if we have enough space.  However, if we
7189          * were marked as full, then we know there aren't enough chunks, and we
7190          * can just return.
7191          */
7192         ret = -1;
7193         if (full)
7194                 goto out;
7195
7196         /*
7197          * index:
7198          *      0: raid10
7199          *      1: raid1
7200          *      2: dup
7201          *      3: raid0
7202          *      4: single
7203          */
7204         index = get_block_group_index(block_group);
7205         if (index == 0) {
7206                 dev_min = 4;
7207                 /* Divide by 2 */
7208                 min_free >>= 1;
7209         } else if (index == 1) {
7210                 dev_min = 2;
7211         } else if (index == 2) {
7212                 /* Multiply by 2 */
7213                 min_free <<= 1;
7214         } else if (index == 3) {
7215                 dev_min = fs_devices->rw_devices;
7216                 do_div(min_free, dev_min);
7217         }
7218
7219         mutex_lock(&root->fs_info->chunk_mutex);
7220         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7221                 u64 dev_offset;
7222
7223                 /*
7224                  * check to make sure we can actually find a chunk with enough
7225                  * space to fit our block group in.
7226                  */
7227                 if (device->total_bytes > device->bytes_used + min_free) {
7228                         ret = find_free_dev_extent(device, min_free,
7229                                                    &dev_offset, NULL);
7230                         if (!ret)
7231                                 dev_nr++;
7232
7233                         if (dev_nr >= dev_min)
7234                                 break;
7235
7236                         ret = -1;
7237                 }
7238         }
7239         mutex_unlock(&root->fs_info->chunk_mutex);
7240 out:
7241         btrfs_put_block_group(block_group);
7242         return ret;
7243 }
7244
7245 static int find_first_block_group(struct btrfs_root *root,
7246                 struct btrfs_path *path, struct btrfs_key *key)
7247 {
7248         int ret = 0;
7249         struct btrfs_key found_key;
7250         struct extent_buffer *leaf;
7251         int slot;
7252
7253         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7254         if (ret < 0)
7255                 goto out;
7256
7257         while (1) {
7258                 slot = path->slots[0];
7259                 leaf = path->nodes[0];
7260                 if (slot >= btrfs_header_nritems(leaf)) {
7261                         ret = btrfs_next_leaf(root, path);
7262                         if (ret == 0)
7263                                 continue;
7264                         if (ret < 0)
7265                                 goto out;
7266                         break;
7267                 }
7268                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7269
7270                 if (found_key.objectid >= key->objectid &&
7271                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7272                         ret = 0;
7273                         goto out;
7274                 }
7275                 path->slots[0]++;
7276         }
7277 out:
7278         return ret;
7279 }
7280
7281 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7282 {
7283         struct btrfs_block_group_cache *block_group;
7284         u64 last = 0;
7285
7286         while (1) {
7287                 struct inode *inode;
7288
7289                 block_group = btrfs_lookup_first_block_group(info, last);
7290                 while (block_group) {
7291                         spin_lock(&block_group->lock);
7292                         if (block_group->iref)
7293                                 break;
7294                         spin_unlock(&block_group->lock);
7295                         block_group = next_block_group(info->tree_root,
7296                                                        block_group);
7297                 }
7298                 if (!block_group) {
7299                         if (last == 0)
7300                                 break;
7301                         last = 0;
7302                         continue;
7303                 }
7304
7305                 inode = block_group->inode;
7306                 block_group->iref = 0;
7307                 block_group->inode = NULL;
7308                 spin_unlock(&block_group->lock);
7309                 iput(inode);
7310                 last = block_group->key.objectid + block_group->key.offset;
7311                 btrfs_put_block_group(block_group);
7312         }
7313 }
7314
7315 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7316 {
7317         struct btrfs_block_group_cache *block_group;
7318         struct btrfs_space_info *space_info;
7319         struct btrfs_caching_control *caching_ctl;
7320         struct rb_node *n;
7321
7322         down_write(&info->extent_commit_sem);
7323         while (!list_empty(&info->caching_block_groups)) {
7324                 caching_ctl = list_entry(info->caching_block_groups.next,
7325                                          struct btrfs_caching_control, list);
7326                 list_del(&caching_ctl->list);
7327                 put_caching_control(caching_ctl);
7328         }
7329         up_write(&info->extent_commit_sem);
7330
7331         spin_lock(&info->block_group_cache_lock);
7332         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7333                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7334                                        cache_node);
7335                 rb_erase(&block_group->cache_node,
7336                          &info->block_group_cache_tree);
7337                 spin_unlock(&info->block_group_cache_lock);
7338
7339                 down_write(&block_group->space_info->groups_sem);
7340                 list_del(&block_group->list);
7341                 up_write(&block_group->space_info->groups_sem);
7342
7343                 if (block_group->cached == BTRFS_CACHE_STARTED)
7344                         wait_block_group_cache_done(block_group);
7345
7346                 /*
7347                  * We haven't cached this block group, which means we could
7348                  * possibly have excluded extents on this block group.
7349                  */
7350                 if (block_group->cached == BTRFS_CACHE_NO)
7351                         free_excluded_extents(info->extent_root, block_group);
7352
7353                 btrfs_remove_free_space_cache(block_group);
7354                 btrfs_put_block_group(block_group);
7355
7356                 spin_lock(&info->block_group_cache_lock);
7357         }
7358         spin_unlock(&info->block_group_cache_lock);
7359
7360         /* now that all the block groups are freed, go through and
7361          * free all the space_info structs.  This is only called during
7362          * the final stages of unmount, and so we know nobody is
7363          * using them.  We call synchronize_rcu() once before we start,
7364          * just to be on the safe side.
7365          */
7366         synchronize_rcu();
7367
7368         release_global_block_rsv(info);
7369
7370         while(!list_empty(&info->space_info)) {
7371                 space_info = list_entry(info->space_info.next,
7372                                         struct btrfs_space_info,
7373                                         list);
7374                 if (space_info->bytes_pinned > 0 ||
7375                     space_info->bytes_reserved > 0 ||
7376                     space_info->bytes_may_use > 0) {
7377                         WARN_ON(1);
7378                         dump_space_info(space_info, 0, 0);
7379                 }
7380                 list_del(&space_info->list);
7381                 kfree(space_info);
7382         }
7383         return 0;
7384 }
7385
7386 static void __link_block_group(struct btrfs_space_info *space_info,
7387                                struct btrfs_block_group_cache *cache)
7388 {
7389         int index = get_block_group_index(cache);
7390
7391         down_write(&space_info->groups_sem);
7392         list_add_tail(&cache->list, &space_info->block_groups[index]);
7393         up_write(&space_info->groups_sem);
7394 }
7395
7396 int btrfs_read_block_groups(struct btrfs_root *root)
7397 {
7398         struct btrfs_path *path;
7399         int ret;
7400         struct btrfs_block_group_cache *cache;
7401         struct btrfs_fs_info *info = root->fs_info;
7402         struct btrfs_space_info *space_info;
7403         struct btrfs_key key;
7404         struct btrfs_key found_key;
7405         struct extent_buffer *leaf;
7406         int need_clear = 0;
7407         u64 cache_gen;
7408
7409         root = info->extent_root;
7410         key.objectid = 0;
7411         key.offset = 0;
7412         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
7413         path = btrfs_alloc_path();
7414         if (!path)
7415                 return -ENOMEM;
7416         path->reada = 1;
7417
7418         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
7419         if (btrfs_test_opt(root, SPACE_CACHE) &&
7420             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
7421                 need_clear = 1;
7422         if (btrfs_test_opt(root, CLEAR_CACHE))
7423                 need_clear = 1;
7424
7425         while (1) {
7426                 ret = find_first_block_group(root, path, &key);
7427                 if (ret > 0)
7428                         break;
7429                 if (ret != 0)
7430                         goto error;
7431                 leaf = path->nodes[0];
7432                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
7433                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
7434                 if (!cache) {
7435                         ret = -ENOMEM;
7436                         goto error;
7437                 }
7438                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7439                                                 GFP_NOFS);
7440                 if (!cache->free_space_ctl) {
7441                         kfree(cache);
7442                         ret = -ENOMEM;
7443                         goto error;
7444                 }
7445
7446                 atomic_set(&cache->count, 1);
7447                 spin_lock_init(&cache->lock);
7448                 cache->fs_info = info;
7449                 INIT_LIST_HEAD(&cache->list);
7450                 INIT_LIST_HEAD(&cache->cluster_list);
7451
7452                 if (need_clear)
7453                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7454
7455                 read_extent_buffer(leaf, &cache->item,
7456                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7457                                    sizeof(cache->item));
7458                 memcpy(&cache->key, &found_key, sizeof(found_key));
7459
7460                 key.objectid = found_key.objectid + found_key.offset;
7461                 btrfs_release_path(path);
7462                 cache->flags = btrfs_block_group_flags(&cache->item);
7463                 cache->sectorsize = root->sectorsize;
7464
7465                 btrfs_init_free_space_ctl(cache);
7466
7467                 /*
7468                  * We need to exclude the super stripes now so that the space
7469                  * info has super bytes accounted for, otherwise we'll think
7470                  * we have more space than we actually do.
7471                  */
7472                 exclude_super_stripes(root, cache);
7473
7474                 /*
7475                  * check for two cases, either we are full, and therefore
7476                  * don't need to bother with the caching work since we won't
7477                  * find any space, or we are empty, and we can just add all
7478                  * the space in and be done with it.  This saves us _alot_ of
7479                  * time, particularly in the full case.
7480                  */
7481                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7482                         cache->last_byte_to_unpin = (u64)-1;
7483                         cache->cached = BTRFS_CACHE_FINISHED;
7484                         free_excluded_extents(root, cache);
7485                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7486                         cache->last_byte_to_unpin = (u64)-1;
7487                         cache->cached = BTRFS_CACHE_FINISHED;
7488                         add_new_free_space(cache, root->fs_info,
7489                                            found_key.objectid,
7490                                            found_key.objectid +
7491                                            found_key.offset);
7492                         free_excluded_extents(root, cache);
7493                 }
7494
7495                 ret = update_space_info(info, cache->flags, found_key.offset,
7496                                         btrfs_block_group_used(&cache->item),
7497                                         &space_info);
7498                 BUG_ON(ret);
7499                 cache->space_info = space_info;
7500                 spin_lock(&cache->space_info->lock);
7501                 cache->space_info->bytes_readonly += cache->bytes_super;
7502                 spin_unlock(&cache->space_info->lock);
7503
7504                 __link_block_group(space_info, cache);
7505
7506                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7507                 BUG_ON(ret);
7508
7509                 set_avail_alloc_bits(root->fs_info, cache->flags);
7510                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7511                         set_block_group_ro(cache, 1);
7512         }
7513
7514         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7515                 if (!(get_alloc_profile(root, space_info->flags) &
7516                       (BTRFS_BLOCK_GROUP_RAID10 |
7517                        BTRFS_BLOCK_GROUP_RAID1 |
7518                        BTRFS_BLOCK_GROUP_DUP)))
7519                         continue;
7520                 /*
7521                  * avoid allocating from un-mirrored block group if there are
7522                  * mirrored block groups.
7523                  */
7524                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7525                         set_block_group_ro(cache, 1);
7526                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7527                         set_block_group_ro(cache, 1);
7528         }
7529
7530         init_global_block_rsv(info);
7531         ret = 0;
7532 error:
7533         btrfs_free_path(path);
7534         return ret;
7535 }
7536
7537 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7538                            struct btrfs_root *root, u64 bytes_used,
7539                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7540                            u64 size)
7541 {
7542         int ret;
7543         struct btrfs_root *extent_root;
7544         struct btrfs_block_group_cache *cache;
7545
7546         extent_root = root->fs_info->extent_root;
7547
7548         root->fs_info->last_trans_log_full_commit = trans->transid;
7549
7550         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7551         if (!cache)
7552                 return -ENOMEM;
7553         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7554                                         GFP_NOFS);
7555         if (!cache->free_space_ctl) {
7556                 kfree(cache);
7557                 return -ENOMEM;
7558         }
7559
7560         cache->key.objectid = chunk_offset;
7561         cache->key.offset = size;
7562         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7563         cache->sectorsize = root->sectorsize;
7564         cache->fs_info = root->fs_info;
7565
7566         atomic_set(&cache->count, 1);
7567         spin_lock_init(&cache->lock);
7568         INIT_LIST_HEAD(&cache->list);
7569         INIT_LIST_HEAD(&cache->cluster_list);
7570
7571         btrfs_init_free_space_ctl(cache);
7572
7573         btrfs_set_block_group_used(&cache->item, bytes_used);
7574         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7575         cache->flags = type;
7576         btrfs_set_block_group_flags(&cache->item, type);
7577
7578         cache->last_byte_to_unpin = (u64)-1;
7579         cache->cached = BTRFS_CACHE_FINISHED;
7580         exclude_super_stripes(root, cache);
7581
7582         add_new_free_space(cache, root->fs_info, chunk_offset,
7583                            chunk_offset + size);
7584
7585         free_excluded_extents(root, cache);
7586
7587         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7588                                 &cache->space_info);
7589         BUG_ON(ret);
7590         update_global_block_rsv(root->fs_info);
7591
7592         spin_lock(&cache->space_info->lock);
7593         cache->space_info->bytes_readonly += cache->bytes_super;
7594         spin_unlock(&cache->space_info->lock);
7595
7596         __link_block_group(cache->space_info, cache);
7597
7598         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7599         BUG_ON(ret);
7600
7601         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7602                                 sizeof(cache->item));
7603         BUG_ON(ret);
7604
7605         set_avail_alloc_bits(extent_root->fs_info, type);
7606
7607         return 0;
7608 }
7609
7610 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
7611 {
7612         u64 extra_flags = flags & BTRFS_BLOCK_GROUP_PROFILE_MASK;
7613
7614         /* chunk -> extended profile */
7615         if (extra_flags == 0)
7616                 extra_flags = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
7617
7618         if (flags & BTRFS_BLOCK_GROUP_DATA)
7619                 fs_info->avail_data_alloc_bits &= ~extra_flags;
7620         if (flags & BTRFS_BLOCK_GROUP_METADATA)
7621                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
7622         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
7623                 fs_info->avail_system_alloc_bits &= ~extra_flags;
7624 }
7625
7626 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7627                              struct btrfs_root *root, u64 group_start)
7628 {
7629         struct btrfs_path *path;
7630         struct btrfs_block_group_cache *block_group;
7631         struct btrfs_free_cluster *cluster;
7632         struct btrfs_root *tree_root = root->fs_info->tree_root;
7633         struct btrfs_key key;
7634         struct inode *inode;
7635         int ret;
7636         int index;
7637         int factor;
7638
7639         root = root->fs_info->extent_root;
7640
7641         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7642         BUG_ON(!block_group);
7643         BUG_ON(!block_group->ro);
7644
7645         /*
7646          * Free the reserved super bytes from this block group before
7647          * remove it.
7648          */
7649         free_excluded_extents(root, block_group);
7650
7651         memcpy(&key, &block_group->key, sizeof(key));
7652         index = get_block_group_index(block_group);
7653         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7654                                   BTRFS_BLOCK_GROUP_RAID1 |
7655                                   BTRFS_BLOCK_GROUP_RAID10))
7656                 factor = 2;
7657         else
7658                 factor = 1;
7659
7660         /* make sure this block group isn't part of an allocation cluster */
7661         cluster = &root->fs_info->data_alloc_cluster;
7662         spin_lock(&cluster->refill_lock);
7663         btrfs_return_cluster_to_free_space(block_group, cluster);
7664         spin_unlock(&cluster->refill_lock);
7665
7666         /*
7667          * make sure this block group isn't part of a metadata
7668          * allocation cluster
7669          */
7670         cluster = &root->fs_info->meta_alloc_cluster;
7671         spin_lock(&cluster->refill_lock);
7672         btrfs_return_cluster_to_free_space(block_group, cluster);
7673         spin_unlock(&cluster->refill_lock);
7674
7675         path = btrfs_alloc_path();
7676         if (!path) {
7677                 ret = -ENOMEM;
7678                 goto out;
7679         }
7680
7681         inode = lookup_free_space_inode(tree_root, block_group, path);
7682         if (!IS_ERR(inode)) {
7683                 ret = btrfs_orphan_add(trans, inode);
7684                 BUG_ON(ret);
7685                 clear_nlink(inode);
7686                 /* One for the block groups ref */
7687                 spin_lock(&block_group->lock);
7688                 if (block_group->iref) {
7689                         block_group->iref = 0;
7690                         block_group->inode = NULL;
7691                         spin_unlock(&block_group->lock);
7692                         iput(inode);
7693                 } else {
7694                         spin_unlock(&block_group->lock);
7695                 }
7696                 /* One for our lookup ref */
7697                 btrfs_add_delayed_iput(inode);
7698         }
7699
7700         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7701         key.offset = block_group->key.objectid;
7702         key.type = 0;
7703
7704         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7705         if (ret < 0)
7706                 goto out;
7707         if (ret > 0)
7708                 btrfs_release_path(path);
7709         if (ret == 0) {
7710                 ret = btrfs_del_item(trans, tree_root, path);
7711                 if (ret)
7712                         goto out;
7713                 btrfs_release_path(path);
7714         }
7715
7716         spin_lock(&root->fs_info->block_group_cache_lock);
7717         rb_erase(&block_group->cache_node,
7718                  &root->fs_info->block_group_cache_tree);
7719         spin_unlock(&root->fs_info->block_group_cache_lock);
7720
7721         down_write(&block_group->space_info->groups_sem);
7722         /*
7723          * we must use list_del_init so people can check to see if they
7724          * are still on the list after taking the semaphore
7725          */
7726         list_del_init(&block_group->list);
7727         if (list_empty(&block_group->space_info->block_groups[index]))
7728                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
7729         up_write(&block_group->space_info->groups_sem);
7730
7731         if (block_group->cached == BTRFS_CACHE_STARTED)
7732                 wait_block_group_cache_done(block_group);
7733
7734         btrfs_remove_free_space_cache(block_group);
7735
7736         spin_lock(&block_group->space_info->lock);
7737         block_group->space_info->total_bytes -= block_group->key.offset;
7738         block_group->space_info->bytes_readonly -= block_group->key.offset;
7739         block_group->space_info->disk_total -= block_group->key.offset * factor;
7740         spin_unlock(&block_group->space_info->lock);
7741
7742         memcpy(&key, &block_group->key, sizeof(key));
7743
7744         btrfs_clear_space_info_full(root->fs_info);
7745
7746         btrfs_put_block_group(block_group);
7747         btrfs_put_block_group(block_group);
7748
7749         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
7750         if (ret > 0)
7751                 ret = -EIO;
7752         if (ret < 0)
7753                 goto out;
7754
7755         ret = btrfs_del_item(trans, root, path);
7756 out:
7757         btrfs_free_path(path);
7758         return ret;
7759 }
7760
7761 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
7762 {
7763         struct btrfs_space_info *space_info;
7764         struct btrfs_super_block *disk_super;
7765         u64 features;
7766         u64 flags;
7767         int mixed = 0;
7768         int ret;
7769
7770         disk_super = fs_info->super_copy;
7771         if (!btrfs_super_root(disk_super))
7772                 return 1;
7773
7774         features = btrfs_super_incompat_flags(disk_super);
7775         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
7776                 mixed = 1;
7777
7778         flags = BTRFS_BLOCK_GROUP_SYSTEM;
7779         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7780         if (ret)
7781                 goto out;
7782
7783         if (mixed) {
7784                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
7785                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7786         } else {
7787                 flags = BTRFS_BLOCK_GROUP_METADATA;
7788                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7789                 if (ret)
7790                         goto out;
7791
7792                 flags = BTRFS_BLOCK_GROUP_DATA;
7793                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7794         }
7795 out:
7796         return ret;
7797 }
7798
7799 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
7800 {
7801         return unpin_extent_range(root, start, end);
7802 }
7803
7804 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
7805                                u64 num_bytes, u64 *actual_bytes)
7806 {
7807         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
7808 }
7809
7810 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
7811 {
7812         struct btrfs_fs_info *fs_info = root->fs_info;
7813         struct btrfs_block_group_cache *cache = NULL;
7814         u64 group_trimmed;
7815         u64 start;
7816         u64 end;
7817         u64 trimmed = 0;
7818         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
7819         int ret = 0;
7820
7821         /*
7822          * try to trim all FS space, our block group may start from non-zero.
7823          */
7824         if (range->len == total_bytes)
7825                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
7826         else
7827                 cache = btrfs_lookup_block_group(fs_info, range->start);
7828
7829         while (cache) {
7830                 if (cache->key.objectid >= (range->start + range->len)) {
7831                         btrfs_put_block_group(cache);
7832                         break;
7833                 }
7834
7835                 start = max(range->start, cache->key.objectid);
7836                 end = min(range->start + range->len,
7837                                 cache->key.objectid + cache->key.offset);
7838
7839                 if (end - start >= range->minlen) {
7840                         if (!block_group_cache_done(cache)) {
7841                                 ret = cache_block_group(cache, NULL, root, 0);
7842                                 if (!ret)
7843                                         wait_block_group_cache_done(cache);
7844                         }
7845                         ret = btrfs_trim_block_group(cache,
7846                                                      &group_trimmed,
7847                                                      start,
7848                                                      end,
7849                                                      range->minlen);
7850
7851                         trimmed += group_trimmed;
7852                         if (ret) {
7853                                 btrfs_put_block_group(cache);
7854                                 break;
7855                         }
7856                 }
7857
7858                 cache = next_block_group(fs_info->tree_root, cache);
7859         }
7860
7861         range->len = trimmed;
7862         return ret;
7863 }