fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include "compat.h"
  28 #include "hash.h"
  29 #include "ctree.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "transaction.h"
  33 #include "volumes.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36
  37 /* control flags for do_chunk_alloc's force field
  38  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  39  * if we really need one.
  40  *
  41  * CHUNK_ALLOC_FORCE means it must try to allocate one
  42  *
  43  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  44  * if we have very few chunks already allocated.  This is
  45  * used as part of the clustering code to help make sure
  46  * we have a good pool of storage to cluster in, without
  47  * filling the FS with empty chunks
  48  *
  49  */
  50 enum {
  51         CHUNK_ALLOC_NO_FORCE = 0,
  52         CHUNK_ALLOC_FORCE = 1,
  53         CHUNK_ALLOC_LIMITED = 2,
  54 };
  55
  56 /*
  57  * Control how reservations are dealt with.
  58  *
  59  * RESERVE_FREE - freeing a reservation.
  60  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  61  *   ENOSPC accounting
  62  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  63  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  64  */
  65 enum {
  66         RESERVE_FREE = 0,
  67         RESERVE_ALLOC = 1,
  68         RESERVE_ALLOC_NO_ACCOUNT = 2,
  69 };
  70
  71 static int update_block_group(struct btrfs_trans_handle *trans,
  72                               struct btrfs_root *root,
  73                               u64 bytenr, u64 num_bytes, int alloc);
  74 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  75                                 struct btrfs_root *root,
  76                                 u64 bytenr, u64 num_bytes, u64 parent,
  77                                 u64 root_objectid, u64 owner_objectid,
  78                                 u64 owner_offset, int refs_to_drop,
  79                                 struct btrfs_delayed_extent_op *extra_op);
  80 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  81                                     struct extent_buffer *leaf,
  82                                     struct btrfs_extent_item *ei);
  83 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  84                                       struct btrfs_root *root,
  85                                       u64 parent, u64 root_objectid,
  86                                       u64 flags, u64 owner, u64 offset,
  87                                       struct btrfs_key *ins, int ref_mod);
  88 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  89                                      struct btrfs_root *root,
  90                                      u64 parent, u64 root_objectid,
  91                                      u64 flags, struct btrfs_disk_key *key,
  92                                      int level, struct btrfs_key *ins);
  93 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  94                           struct btrfs_root *extent_root, u64 alloc_bytes,
  95                           u64 flags, int force);
  96 static int find_next_key(struct btrfs_path *path, int level,
  97                          struct btrfs_key *key);
  98 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
  99                             int dump_block_groups);
 100 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 101                                        u64 num_bytes, int reserve);
 102
 103 static noinline int
 104 block_group_cache_done(struct btrfs_block_group_cache *cache)
 105 {
 106         smp_mb();
 107         return cache->cached == BTRFS_CACHE_FINISHED;
 108 }
 109
 110 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 111 {
 112         return (cache->flags & bits) == bits;
 113 }
 114
 115 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 116 {
 117         atomic_inc(&cache->count);
 118 }
 119
 120 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 121 {
 122         if (atomic_dec_and_test(&cache->count)) {
 123                 WARN_ON(cache->pinned > 0);
 124                 WARN_ON(cache->reserved > 0);
 125                 kfree(cache->free_space_ctl);
 126                 kfree(cache);
 127         }
 128 }
 129
 130 /*
 131  * this adds the block group to the fs_info rb tree for the block group
 132  * cache
 133  */
 134 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 135                                 struct btrfs_block_group_cache *block_group)
 136 {
 137         struct rb_node **p;
 138         struct rb_node *parent = NULL;
 139         struct btrfs_block_group_cache *cache;
 140
 141         spin_lock(&info->block_group_cache_lock);
 142         p = &info->block_group_cache_tree.rb_node;
 143
 144         while (*p) {
 145                 parent = *p;
 146                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 147                                  cache_node);
 148                 if (block_group->key.objectid < cache->key.objectid) {
 149                         p = &(*p)->rb_left;
 150                 } else if (block_group->key.objectid > cache->key.objectid) {
 151                         p = &(*p)->rb_right;
 152                 } else {
 153                         spin_unlock(&info->block_group_cache_lock);
 154                         return -EEXIST;
 155                 }
 156         }
 157
 158         rb_link_node(&block_group->cache_node, parent, p);
 159         rb_insert_color(&block_group->cache_node,
 160                         &info->block_group_cache_tree);
 161         spin_unlock(&info->block_group_cache_lock);
 162
 163         return 0;
 164 }
 165
 166 /*
 167  * This will return the block group at or after bytenr if contains is 0, else
 168  * it will return the block group that contains the bytenr
 169  */
 170 static struct btrfs_block_group_cache *
 171 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 172                               int contains)
 173 {
 174         struct btrfs_block_group_cache *cache, *ret = NULL;
 175         struct rb_node *n;
 176         u64 end, start;
 177
 178         spin_lock(&info->block_group_cache_lock);
 179         n = info->block_group_cache_tree.rb_node;
 180
 181         while (n) {
 182                 cache = rb_entry(n, struct btrfs_block_group_cache,
 183                                  cache_node);
 184                 end = cache->key.objectid + cache->key.offset - 1;
 185                 start = cache->key.objectid;
 186
 187                 if (bytenr < start) {
 188                         if (!contains && (!ret || start < ret->key.objectid))
 189                                 ret = cache;
 190                         n = n->rb_left;
 191                 } else if (bytenr > start) {
 192                         if (contains && bytenr <= end) {
 193                                 ret = cache;
 194                                 break;
 195                         }
 196                         n = n->rb_right;
 197                 } else {
 198                         ret = cache;
 199                         break;
 200                 }
 201         }
 202         if (ret)
 203                 btrfs_get_block_group(ret);
 204         spin_unlock(&info->block_group_cache_lock);
 205
 206         return ret;
 207 }
 208
 209 static int add_excluded_extent(struct btrfs_root *root,
 210                                u64 start, u64 num_bytes)
 211 {
 212         u64 end = start + num_bytes - 1;
 213         set_extent_bits(&root->fs_info->freed_extents[0],
 214                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 215         set_extent_bits(&root->fs_info->freed_extents[1],
 216                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 217         return 0;
 218 }
 219
 220 static void free_excluded_extents(struct btrfs_root *root,
 221                                   struct btrfs_block_group_cache *cache)
 222 {
 223         u64 start, end;
 224
 225         start = cache->key.objectid;
 226         end = start + cache->key.offset - 1;
 227
 228         clear_extent_bits(&root->fs_info->freed_extents[0],
 229                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 230         clear_extent_bits(&root->fs_info->freed_extents[1],
 231                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 232 }
 233
 234 static int exclude_super_stripes(struct btrfs_root *root,
 235                                  struct btrfs_block_group_cache *cache)
 236 {
 237         u64 bytenr;
 238         u64 *logical;
 239         int stripe_len;
 240         int i, nr, ret;
 241
 242         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 243                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 244                 cache->bytes_super += stripe_len;
 245                 ret = add_excluded_extent(root, cache->key.objectid,
 246                                           stripe_len);
 247                 BUG_ON(ret);
 248         }
 249
 250         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 251                 bytenr = btrfs_sb_offset(i);
 252                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 253                                        cache->key.objectid, bytenr,
 254                                        0, &logical, &nr, &stripe_len);
 255                 BUG_ON(ret);
 256
 257                 while (nr--) {
 258                         cache->bytes_super += stripe_len;
 259                         ret = add_excluded_extent(root, logical[nr],
 260                                                   stripe_len);
 261                         BUG_ON(ret);
 262                 }
 263
 264                 kfree(logical);
 265         }
 266         return 0;
 267 }
 268
 269 static struct btrfs_caching_control *
 270 get_caching_control(struct btrfs_block_group_cache *cache)
 271 {
 272         struct btrfs_caching_control *ctl;
 273
 274         spin_lock(&cache->lock);
 275         if (cache->cached != BTRFS_CACHE_STARTED) {
 276                 spin_unlock(&cache->lock);
 277                 return NULL;
 278         }
 279
 280         /* We're loading it the fast way, so we don't have a caching_ctl. */
 281         if (!cache->caching_ctl) {
 282                 spin_unlock(&cache->lock);
 283                 return NULL;
 284         }
 285
 286         ctl = cache->caching_ctl;
 287         atomic_inc(&ctl->count);
 288         spin_unlock(&cache->lock);
 289         return ctl;
 290 }
 291
 292 static void put_caching_control(struct btrfs_caching_control *ctl)
 293 {
 294         if (atomic_dec_and_test(&ctl->count))
 295                 kfree(ctl);
 296 }
 297
 298 /*
 299  * this is only called by cache_block_group, since we could have freed extents
 300  * we need to check the pinned_extents for any extents that can't be used yet
 301  * since their free space will be released as soon as the transaction commits.
 302  */
 303 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 304                               struct btrfs_fs_info *info, u64 start, u64 end)
 305 {
 306         u64 extent_start, extent_end, size, total_added = 0;
 307         int ret;
 308
 309         while (start < end) {
 310                 ret = find_first_extent_bit(info->pinned_extents, start,
 311                                             &extent_start, &extent_end,
 312                                             EXTENT_DIRTY | EXTENT_UPTODATE);
 313                 if (ret)
 314                         break;
 315
 316                 if (extent_start <= start) {
 317                         start = extent_end + 1;
 318                 } else if (extent_start > start && extent_start < end) {
 319                         size = extent_start - start;
 320                         total_added += size;
 321                         ret = btrfs_add_free_space(block_group, start,
 322                                                    size);
 323                         BUG_ON(ret);
 324                         start = extent_end + 1;
 325                 } else {
 326                         break;
 327                 }
 328         }
 329
 330         if (start < end) {
 331                 size = end - start;
 332                 total_added += size;
 333                 ret = btrfs_add_free_space(block_group, start, size);
 334                 BUG_ON(ret);
 335         }
 336
 337         return total_added;
 338 }
 339
 340 static noinline void caching_thread(struct btrfs_work *work)
 341 {
 342         struct btrfs_block_group_cache *block_group;
 343         struct btrfs_fs_info *fs_info;
 344         struct btrfs_caching_control *caching_ctl;
 345         struct btrfs_root *extent_root;
 346         struct btrfs_path *path;
 347         struct extent_buffer *leaf;
 348         struct btrfs_key key;
 349         u64 total_found = 0;
 350         u64 last = 0;
 351         u32 nritems;
 352         int ret = 0;
 353
 354         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 355         block_group = caching_ctl->block_group;
 356         fs_info = block_group->fs_info;
 357         extent_root = fs_info->extent_root;
 358
 359         path = btrfs_alloc_path();
 360         if (!path)
 361                 goto out;
 362
 363         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 364
 365         /*
 366          * We don't want to deadlock with somebody trying to allocate a new
 367          * extent for the extent root while also trying to search the extent
 368          * root to add free space.  So we skip locking and search the commit
 369          * root, since its read-only
 370          */
 371         path->skip_locking = 1;
 372         path->search_commit_root = 1;
 373         path->reada = 1;
 374
 375         key.objectid = last;
 376         key.offset = 0;
 377         key.type = BTRFS_EXTENT_ITEM_KEY;
 378 again:
 379         mutex_lock(&caching_ctl->mutex);
 380         /* need to make sure the commit_root doesn't disappear */
 381         down_read(&fs_info->extent_commit_sem);
 382
 383         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 384         if (ret < 0)
 385                 goto err;
 386
 387         leaf = path->nodes[0];
 388         nritems = btrfs_header_nritems(leaf);
 389
 390         while (1) {
 391                 if (btrfs_fs_closing(fs_info) > 1) {
 392                         last = (u64)-1;
 393                         break;
 394                 }
 395
 396                 if (path->slots[0] < nritems) {
 397                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 398                 } else {
 399                         ret = find_next_key(path, 0, &key);
 400                         if (ret)
 401                                 break;
 402
 403                         if (need_resched() ||
 404                             btrfs_next_leaf(extent_root, path)) {
 405                                 caching_ctl->progress = last;
 406                                 btrfs_release_path(path);
 407                                 up_read(&fs_info->extent_commit_sem);
 408                                 mutex_unlock(&caching_ctl->mutex);
 409                                 cond_resched();
 410                                 goto again;
 411                         }
 412                         leaf = path->nodes[0];
 413                         nritems = btrfs_header_nritems(leaf);
 414                         continue;
 415                 }
 416
 417                 if (key.objectid < block_group->key.objectid) {
 418                         path->slots[0]++;
 419                         continue;
 420                 }
 421
 422                 if (key.objectid >= block_group->key.objectid +
 423                     block_group->key.offset)
 424                         break;
 425
 426                 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
 427                         total_found += add_new_free_space(block_group,
 428                                                           fs_info, last,
 429                                                           key.objectid);
 430                         last = key.objectid + key.offset;
 431
 432                         if (total_found > (1024 * 1024 * 2)) {
 433                                 total_found = 0;
 434                                 wake_up(&caching_ctl->wait);
 435                         }
 436                 }
 437                 path->slots[0]++;
 438         }
 439         ret = 0;
 440
 441         total_found += add_new_free_space(block_group, fs_info, last,
 442                                           block_group->key.objectid +
 443                                           block_group->key.offset);
 444         caching_ctl->progress = (u64)-1;
 445
 446         spin_lock(&block_group->lock);
 447         block_group->caching_ctl = NULL;
 448         block_group->cached = BTRFS_CACHE_FINISHED;
 449         spin_unlock(&block_group->lock);
 450
 451 err:
 452         btrfs_free_path(path);
 453         up_read(&fs_info->extent_commit_sem);
 454
 455         free_excluded_extents(extent_root, block_group);
 456
 457         mutex_unlock(&caching_ctl->mutex);
 458 out:
 459         wake_up(&caching_ctl->wait);
 460
 461         put_caching_control(caching_ctl);
 462         btrfs_put_block_group(block_group);
 463 }
 464
 465 static int cache_block_group(struct btrfs_block_group_cache *cache,
 466                              struct btrfs_trans_handle *trans,
 467                              struct btrfs_root *root,
 468                              int load_cache_only)
 469 {
 470         DEFINE_WAIT(wait);
 471         struct btrfs_fs_info *fs_info = cache->fs_info;
 472         struct btrfs_caching_control *caching_ctl;
 473         int ret = 0;
 474
 475         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 476         BUG_ON(!caching_ctl);
 477
 478         INIT_LIST_HEAD(&caching_ctl->list);
 479         mutex_init(&caching_ctl->mutex);
 480         init_waitqueue_head(&caching_ctl->wait);
 481         caching_ctl->block_group = cache;
 482         caching_ctl->progress = cache->key.objectid;
 483         atomic_set(&caching_ctl->count, 1);
 484         caching_ctl->work.func = caching_thread;
 485
 486         spin_lock(&cache->lock);
 487         /*
 488          * This should be a rare occasion, but this could happen I think in the
 489          * case where one thread starts to load the space cache info, and then
 490          * some other thread starts a transaction commit which tries to do an
 491          * allocation while the other thread is still loading the space cache
 492          * info.  The previous loop should have kept us from choosing this block
 493          * group, but if we've moved to the state where we will wait on caching
 494          * block groups we need to first check if we're doing a fast load here,
 495          * so we can wait for it to finish, otherwise we could end up allocating
 496          * from a block group who's cache gets evicted for one reason or
 497          * another.
 498          */
 499         while (cache->cached == BTRFS_CACHE_FAST) {
 500                 struct btrfs_caching_control *ctl;
 501
 502                 ctl = cache->caching_ctl;
 503                 atomic_inc(&ctl->count);
 504                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 505                 spin_unlock(&cache->lock);
 506
 507                 schedule();
 508
 509                 finish_wait(&ctl->wait, &wait);
 510                 put_caching_control(ctl);
 511                 spin_lock(&cache->lock);
 512         }
 513
 514         if (cache->cached != BTRFS_CACHE_NO) {
 515                 spin_unlock(&cache->lock);
 516                 kfree(caching_ctl);
 517                 return 0;
 518         }
 519         WARN_ON(cache->caching_ctl);
 520         cache->caching_ctl = caching_ctl;
 521         cache->cached = BTRFS_CACHE_FAST;
 522         spin_unlock(&cache->lock);
 523
 524         /*
 525          * We can't do the read from on-disk cache during a commit since we need
 526          * to have the normal tree locking.  Also if we are currently trying to
 527          * allocate blocks for the tree root we can't do the fast caching since
 528          * we likely hold important locks.
 529          */
 530         if (trans && (!trans->transaction->in_commit) &&
 531             (root && root != root->fs_info->tree_root) &&
 532             btrfs_test_opt(root, SPACE_CACHE)) {
 533                 ret = load_free_space_cache(fs_info, cache);
 534
 535                 spin_lock(&cache->lock);
 536                 if (ret == 1) {
 537                         cache->caching_ctl = NULL;
 538                         cache->cached = BTRFS_CACHE_FINISHED;
 539                         cache->last_byte_to_unpin = (u64)-1;
 540                 } else {
 541                         if (load_cache_only) {
 542                                 cache->caching_ctl = NULL;
 543                                 cache->cached = BTRFS_CACHE_NO;
 544                         } else {
 545                                 cache->cached = BTRFS_CACHE_STARTED;
 546                         }
 547                 }
 548                 spin_unlock(&cache->lock);
 549                 wake_up(&caching_ctl->wait);
 550                 if (ret == 1) {
 551                         put_caching_control(caching_ctl);
 552                         free_excluded_extents(fs_info->extent_root, cache);
 553                         return 0;
 554                 }
 555         } else {
 556                 /*
 557                  * We are not going to do the fast caching, set cached to the
 558                  * appropriate value and wakeup any waiters.
 559                  */
 560                 spin_lock(&cache->lock);
 561                 if (load_cache_only) {
 562                         cache->caching_ctl = NULL;
 563                         cache->cached = BTRFS_CACHE_NO;
 564                 } else {
 565                         cache->cached = BTRFS_CACHE_STARTED;
 566                 }
 567                 spin_unlock(&cache->lock);
 568                 wake_up(&caching_ctl->wait);
 569         }
 570
 571         if (load_cache_only) {
 572                 put_caching_control(caching_ctl);
 573                 return 0;
 574         }
 575
 576         down_write(&fs_info->extent_commit_sem);
 577         atomic_inc(&caching_ctl->count);
 578         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 579         up_write(&fs_info->extent_commit_sem);
 580
 581         btrfs_get_block_group(cache);
 582
 583         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 584
 585         return ret;
 586 }
 587
 588 /*
 589  * return the block group that starts at or after bytenr
 590  */
 591 static struct btrfs_block_group_cache *
 592 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 593 {
 594         struct btrfs_block_group_cache *cache;
 595
 596         cache = block_group_cache_tree_search(info, bytenr, 0);
 597
 598         return cache;
 599 }
 600
 601 /*
 602  * return the block group that contains the given bytenr
 603  */
 604 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 605                                                  struct btrfs_fs_info *info,
 606                                                  u64 bytenr)
 607 {
 608         struct btrfs_block_group_cache *cache;
 609
 610         cache = block_group_cache_tree_search(info, bytenr, 1);
 611
 612         return cache;
 613 }
 614
 615 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 616                                                   u64 flags)
 617 {
 618         struct list_head *head = &info->space_info;
 619         struct btrfs_space_info *found;
 620
 621         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 622
 623         rcu_read_lock();
 624         list_for_each_entry_rcu(found, head, list) {
 625                 if (found->flags & flags) {
 626                         rcu_read_unlock();
 627                         return found;
 628                 }
 629         }
 630         rcu_read_unlock();
 631         return NULL;
 632 }
 633
 634 /*
 635  * after adding space to the filesystem, we need to clear the full flags
 636  * on all the space infos.
 637  */
 638 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 639 {
 640         struct list_head *head = &info->space_info;
 641         struct btrfs_space_info *found;
 642
 643         rcu_read_lock();
 644         list_for_each_entry_rcu(found, head, list)
 645                 found->full = 0;
 646         rcu_read_unlock();
 647 }
 648
 649 static u64 div_factor(u64 num, int factor)
 650 {
 651         if (factor == 10)
 652                 return num;
 653         num *= factor;
 654         do_div(num, 10);
 655         return num;
 656 }
 657
 658 static u64 div_factor_fine(u64 num, int factor)
 659 {
 660         if (factor == 100)
 661                 return num;
 662         num *= factor;
 663         do_div(num, 100);
 664         return num;
 665 }
 666
 667 u64 btrfs_find_block_group(struct btrfs_root *root,
 668                            u64 search_start, u64 search_hint, int owner)
 669 {
 670         struct btrfs_block_group_cache *cache;
 671         u64 used;
 672         u64 last = max(search_hint, search_start);
 673         u64 group_start = 0;
 674         int full_search = 0;
 675         int factor = 9;
 676         int wrapped = 0;
 677 again:
 678         while (1) {
 679                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 680                 if (!cache)
 681                         break;
 682
 683                 spin_lock(&cache->lock);
 684                 last = cache->key.objectid + cache->key.offset;
 685                 used = btrfs_block_group_used(&cache->item);
 686
 687                 if ((full_search || !cache->ro) &&
 688                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 689                         if (used + cache->pinned + cache->reserved <
 690                             div_factor(cache->key.offset, factor)) {
 691                                 group_start = cache->key.objectid;
 692                                 spin_unlock(&cache->lock);
 693                                 btrfs_put_block_group(cache);
 694                                 goto found;
 695                         }
 696                 }
 697                 spin_unlock(&cache->lock);
 698                 btrfs_put_block_group(cache);
 699                 cond_resched();
 700         }
 701         if (!wrapped) {
 702                 last = search_start;
 703                 wrapped = 1;
 704                 goto again;
 705         }
 706         if (!full_search && factor < 10) {
 707                 last = search_start;
 708                 full_search = 1;
 709                 factor = 10;
 710                 goto again;
 711         }
 712 found:
 713         return group_start;
 714 }
 715
 716 /* simple helper to search for an existing extent at a given offset */
 717 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 718 {
 719         int ret;
 720         struct btrfs_key key;
 721         struct btrfs_path *path;
 722
 723         path = btrfs_alloc_path();
 724         if (!path)
 725                 return -ENOMEM;
 726
 727         key.objectid = start;
 728         key.offset = len;
 729         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 730         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 731                                 0, 0);
 732         btrfs_free_path(path);
 733         return ret;
 734 }
 735
 736 /*
 737  * helper function to lookup reference count and flags of extent.
 738  *
 739  * the head node for delayed ref is used to store the sum of all the
 740  * reference count modifications queued up in the rbtree. the head
 741  * node may also store the extent flags to set. This way you can check
 742  * to see what the reference count and extent flags would be if all of
 743  * the delayed refs are not processed.
 744  */
 745 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 746                              struct btrfs_root *root, u64 bytenr,
 747                              u64 num_bytes, u64 *refs, u64 *flags)
 748 {
 749         struct btrfs_delayed_ref_head *head;
 750         struct btrfs_delayed_ref_root *delayed_refs;
 751         struct btrfs_path *path;
 752         struct btrfs_extent_item *ei;
 753         struct extent_buffer *leaf;
 754         struct btrfs_key key;
 755         u32 item_size;
 756         u64 num_refs;
 757         u64 extent_flags;
 758         int ret;
 759
 760         path = btrfs_alloc_path();
 761         if (!path)
 762                 return -ENOMEM;
 763
 764         key.objectid = bytenr;
 765         key.type = BTRFS_EXTENT_ITEM_KEY;
 766         key.offset = num_bytes;
 767         if (!trans) {
 768                 path->skip_locking = 1;
 769                 path->search_commit_root = 1;
 770         }
 771 again:
 772         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 773                                 &key, path, 0, 0);
 774         if (ret < 0)
 775                 goto out_free;
 776
 777         if (ret == 0) {
 778                 leaf = path->nodes[0];
 779                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 780                 if (item_size >= sizeof(*ei)) {
 781                         ei = btrfs_item_ptr(leaf, path->slots[0],
 782                                             struct btrfs_extent_item);
 783                         num_refs = btrfs_extent_refs(leaf, ei);
 784                         extent_flags = btrfs_extent_flags(leaf, ei);
 785                 } else {
 786 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 787                         struct btrfs_extent_item_v0 *ei0;
 788                         BUG_ON(item_size != sizeof(*ei0));
 789                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 790                                              struct btrfs_extent_item_v0);
 791                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 792                         /* FIXME: this isn't correct for data */
 793                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 794 #else
 795                         BUG();
 796 #endif
 797                 }
 798                 BUG_ON(num_refs == 0);
 799         } else {
 800                 num_refs = 0;
 801                 extent_flags = 0;
 802                 ret = 0;
 803         }
 804
 805         if (!trans)
 806                 goto out;
 807
 808         delayed_refs = &trans->transaction->delayed_refs;
 809         spin_lock(&delayed_refs->lock);
 810         head = btrfs_find_delayed_ref_head(trans, bytenr);
 811         if (head) {
 812                 if (!mutex_trylock(&head->mutex)) {
 813                         atomic_inc(&head->node.refs);
 814                         spin_unlock(&delayed_refs->lock);
 815
 816                         btrfs_release_path(path);
 817
 818                         /*
 819                          * Mutex was contended, block until it's released and try
 820                          * again
 821                          */
 822                         mutex_lock(&head->mutex);
 823                         mutex_unlock(&head->mutex);
 824                         btrfs_put_delayed_ref(&head->node);
 825                         goto again;
 826                 }
 827                 if (head->extent_op && head->extent_op->update_flags)
 828                         extent_flags |= head->extent_op->flags_to_set;
 829                 else
 830                         BUG_ON(num_refs == 0);
 831
 832                 num_refs += head->node.ref_mod;
 833                 mutex_unlock(&head->mutex);
 834         }
 835         spin_unlock(&delayed_refs->lock);
 836 out:
 837         WARN_ON(num_refs == 0);
 838         if (refs)
 839                 *refs = num_refs;
 840         if (flags)
 841                 *flags = extent_flags;
 842 out_free:
 843         btrfs_free_path(path);
 844         return ret;
 845 }
 846
 847 /*
 848  * Back reference rules.  Back refs have three main goals:
 849  *
 850  * 1) differentiate between all holders of references to an extent so that
 851  *    when a reference is dropped we can make sure it was a valid reference
 852  *    before freeing the extent.
 853  *
 854  * 2) Provide enough information to quickly find the holders of an extent
 855  *    if we notice a given block is corrupted or bad.
 856  *
 857  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 858  *    maintenance.  This is actually the same as #2, but with a slightly
 859  *    different use case.
 860  *
 861  * There are two kinds of back refs. The implicit back refs is optimized
 862  * for pointers in non-shared tree blocks. For a given pointer in a block,
 863  * back refs of this kind provide information about the block's owner tree
 864  * and the pointer's key. These information allow us to find the block by
 865  * b-tree searching. The full back refs is for pointers in tree blocks not
 866  * referenced by their owner trees. The location of tree block is recorded
 867  * in the back refs. Actually the full back refs is generic, and can be
 868  * used in all cases the implicit back refs is used. The major shortcoming
 869  * of the full back refs is its overhead. Every time a tree block gets
 870  * COWed, we have to update back refs entry for all pointers in it.
 871  *
 872  * For a newly allocated tree block, we use implicit back refs for
 873  * pointers in it. This means most tree related operations only involve
 874  * implicit back refs. For a tree block created in old transaction, the
 875  * only way to drop a reference to it is COW it. So we can detect the
 876  * event that tree block loses its owner tree's reference and do the
 877  * back refs conversion.
 878  *
 879  * When a tree block is COW'd through a tree, there are four cases:
 880  *
 881  * The reference count of the block is one and the tree is the block's
 882  * owner tree. Nothing to do in this case.
 883  *
 884  * The reference count of the block is one and the tree is not the
 885  * block's owner tree. In this case, full back refs is used for pointers
 886  * in the block. Remove these full back refs, add implicit back refs for
 887  * every pointers in the new block.
 888  *
 889  * The reference count of the block is greater than one and the tree is
 890  * the block's owner tree. In this case, implicit back refs is used for
 891  * pointers in the block. Add full back refs for every pointers in the
 892  * block, increase lower level extents' reference counts. The original
 893  * implicit back refs are entailed to the new block.
 894  *
 895  * The reference count of the block is greater than one and the tree is
 896  * not the block's owner tree. Add implicit back refs for every pointer in
 897  * the new block, increase lower level extents' reference count.
 898  *
 899  * Back Reference Key composing:
 900  *
 901  * The key objectid corresponds to the first byte in the extent,
 902  * The key type is used to differentiate between types of back refs.
 903  * There are different meanings of the key offset for different types
 904  * of back refs.
 905  *
 906  * File extents can be referenced by:
 907  *
 908  * - multiple snapshots, subvolumes, or different generations in one subvol
 909  * - different files inside a single subvolume
 910  * - different offsets inside a file (bookend extents in file.c)
 911  *
 912  * The extent ref structure for the implicit back refs has fields for:
 913  *
 914  * - Objectid of the subvolume root
 915  * - objectid of the file holding the reference
 916  * - original offset in the file
 917  * - how many bookend extents
 918  *
 919  * The key offset for the implicit back refs is hash of the first
 920  * three fields.
 921  *
 922  * The extent ref structure for the full back refs has field for:
 923  *
 924  * - number of pointers in the tree leaf
 925  *
 926  * The key offset for the implicit back refs is the first byte of
 927  * the tree leaf
 928  *
 929  * When a file extent is allocated, The implicit back refs is used.
 930  * the fields are filled in:
 931  *
 932  *     (root_key.objectid, inode objectid, offset in file, 1)
 933  *
 934  * When a file extent is removed file truncation, we find the
 935  * corresponding implicit back refs and check the following fields:
 936  *
 937  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 938  *
 939  * Btree extents can be referenced by:
 940  *
 941  * - Different subvolumes
 942  *
 943  * Both the implicit back refs and the full back refs for tree blocks
 944  * only consist of key. The key offset for the implicit back refs is
 945  * objectid of block's owner tree. The key offset for the full back refs
 946  * is the first byte of parent block.
 947  *
 948  * When implicit back refs is used, information about the lowest key and
 949  * level of the tree block are required. These information are stored in
 950  * tree block info structure.
 951  */
 952
 953 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 954 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 955                                   struct btrfs_root *root,
 956                                   struct btrfs_path *path,
 957                                   u64 owner, u32 extra_size)
 958 {
 959         struct btrfs_extent_item *item;
 960         struct btrfs_extent_item_v0 *ei0;
 961         struct btrfs_extent_ref_v0 *ref0;
 962         struct btrfs_tree_block_info *bi;
 963         struct extent_buffer *leaf;
 964         struct btrfs_key key;
 965         struct btrfs_key found_key;
 966         u32 new_size = sizeof(*item);
 967         u64 refs;
 968         int ret;
 969
 970         leaf = path->nodes[0];
 971         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 972
 973         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 974         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 975                              struct btrfs_extent_item_v0);
 976         refs = btrfs_extent_refs_v0(leaf, ei0);
 977
 978         if (owner == (u64)-1) {
 979                 while (1) {
 980                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
 981                                 ret = btrfs_next_leaf(root, path);
 982                                 if (ret < 0)
 983                                         return ret;
 984                                 BUG_ON(ret > 0);
 985                                 leaf = path->nodes[0];
 986                         }
 987                         btrfs_item_key_to_cpu(leaf, &found_key,
 988                                               path->slots[0]);
 989                         BUG_ON(key.objectid != found_key.objectid);
 990                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
 991                                 path->slots[0]++;
 992                                 continue;
 993                         }
 994                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
 995                                               struct btrfs_extent_ref_v0);
 996                         owner = btrfs_ref_objectid_v0(leaf, ref0);
 997                         break;
 998                 }
 999         }
1000         btrfs_release_path(path);
1001
1002         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1003                 new_size += sizeof(*bi);
1004
1005         new_size -= sizeof(*ei0);
1006         ret = btrfs_search_slot(trans, root, &key, path,
1007                                 new_size + extra_size, 1);
1008         if (ret < 0)
1009                 return ret;
1010         BUG_ON(ret);
1011
1012         ret = btrfs_extend_item(trans, root, path, new_size);
1013
1014         leaf = path->nodes[0];
1015         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1016         btrfs_set_extent_refs(leaf, item, refs);
1017         /* FIXME: get real generation */
1018         btrfs_set_extent_generation(leaf, item, 0);
1019         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1020                 btrfs_set_extent_flags(leaf, item,
1021                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1022                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1023                 bi = (struct btrfs_tree_block_info *)(item + 1);
1024                 /* FIXME: get first key of the block */
1025                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1026                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1027         } else {
1028                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1029         }
1030         btrfs_mark_buffer_dirty(leaf);
1031         return 0;
1032 }
1033 #endif
1034
1035 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1036 {
1037         u32 high_crc = ~(u32)0;
1038         u32 low_crc = ~(u32)0;
1039         __le64 lenum;
1040
1041         lenum = cpu_to_le64(root_objectid);
1042         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1043         lenum = cpu_to_le64(owner);
1044         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1045         lenum = cpu_to_le64(offset);
1046         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1047
1048         return ((u64)high_crc << 31) ^ (u64)low_crc;
1049 }
1050
1051 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1052                                      struct btrfs_extent_data_ref *ref)
1053 {
1054         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1055                                     btrfs_extent_data_ref_objectid(leaf, ref),
1056                                     btrfs_extent_data_ref_offset(leaf, ref));
1057 }
1058
1059 static int match_extent_data_ref(struct extent_buffer *leaf,
1060                                  struct btrfs_extent_data_ref *ref,
1061                                  u64 root_objectid, u64 owner, u64 offset)
1062 {
1063         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1064             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1065             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1066                 return 0;
1067         return 1;
1068 }
1069
1070 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1071                                            struct btrfs_root *root,
1072                                            struct btrfs_path *path,
1073                                            u64 bytenr, u64 parent,
1074                                            u64 root_objectid,
1075                                            u64 owner, u64 offset)
1076 {
1077         struct btrfs_key key;
1078         struct btrfs_extent_data_ref *ref;
1079         struct extent_buffer *leaf;
1080         u32 nritems;
1081         int ret;
1082         int recow;
1083         int err = -ENOENT;
1084
1085         key.objectid = bytenr;
1086         if (parent) {
1087                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1088                 key.offset = parent;
1089         } else {
1090                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1091                 key.offset = hash_extent_data_ref(root_objectid,
1092                                                   owner, offset);
1093         }
1094 again:
1095         recow = 0;
1096         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1097         if (ret < 0) {
1098                 err = ret;
1099                 goto fail;
1100         }
1101
1102         if (parent) {
1103                 if (!ret)
1104                         return 0;
1105 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1106                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1107                 btrfs_release_path(path);
1108                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1109                 if (ret < 0) {
1110                         err = ret;
1111                         goto fail;
1112                 }
1113                 if (!ret)
1114                         return 0;
1115 #endif
1116                 goto fail;
1117         }
1118
1119         leaf = path->nodes[0];
1120         nritems = btrfs_header_nritems(leaf);
1121         while (1) {
1122                 if (path->slots[0] >= nritems) {
1123                         ret = btrfs_next_leaf(root, path);
1124                         if (ret < 0)
1125                                 err = ret;
1126                         if (ret)
1127                                 goto fail;
1128
1129                         leaf = path->nodes[0];
1130                         nritems = btrfs_header_nritems(leaf);
1131                         recow = 1;
1132                 }
1133
1134                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1135                 if (key.objectid != bytenr ||
1136                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1137                         goto fail;
1138
1139                 ref = btrfs_item_ptr(leaf, path->slots[0],
1140                                      struct btrfs_extent_data_ref);
1141
1142                 if (match_extent_data_ref(leaf, ref, root_objectid,
1143                                           owner, offset)) {
1144                         if (recow) {
1145                                 btrfs_release_path(path);
1146                                 goto again;
1147                         }
1148                         err = 0;
1149                         break;
1150                 }
1151                 path->slots[0]++;
1152         }
1153 fail:
1154         return err;
1155 }
1156
1157 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1158                                            struct btrfs_root *root,
1159                                            struct btrfs_path *path,
1160                                            u64 bytenr, u64 parent,
1161                                            u64 root_objectid, u64 owner,
1162                                            u64 offset, int refs_to_add)
1163 {
1164         struct btrfs_key key;
1165         struct extent_buffer *leaf;
1166         u32 size;
1167         u32 num_refs;
1168         int ret;
1169
1170         key.objectid = bytenr;
1171         if (parent) {
1172                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1173                 key.offset = parent;
1174                 size = sizeof(struct btrfs_shared_data_ref);
1175         } else {
1176                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1177                 key.offset = hash_extent_data_ref(root_objectid,
1178                                                   owner, offset);
1179                 size = sizeof(struct btrfs_extent_data_ref);
1180         }
1181
1182         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1183         if (ret && ret != -EEXIST)
1184                 goto fail;
1185
1186         leaf = path->nodes[0];
1187         if (parent) {
1188                 struct btrfs_shared_data_ref *ref;
1189                 ref = btrfs_item_ptr(leaf, path->slots[0],
1190                                      struct btrfs_shared_data_ref);
1191                 if (ret == 0) {
1192                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1193                 } else {
1194                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1195                         num_refs += refs_to_add;
1196                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1197                 }
1198         } else {
1199                 struct btrfs_extent_data_ref *ref;
1200                 while (ret == -EEXIST) {
1201                         ref = btrfs_item_ptr(leaf, path->slots[0],
1202                                              struct btrfs_extent_data_ref);
1203                         if (match_extent_data_ref(leaf, ref, root_objectid,
1204                                                   owner, offset))
1205                                 break;
1206                         btrfs_release_path(path);
1207                         key.offset++;
1208                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1209                                                       size);
1210                         if (ret && ret != -EEXIST)
1211                                 goto fail;
1212
1213                         leaf = path->nodes[0];
1214                 }
1215                 ref = btrfs_item_ptr(leaf, path->slots[0],
1216                                      struct btrfs_extent_data_ref);
1217                 if (ret == 0) {
1218                         btrfs_set_extent_data_ref_root(leaf, ref,
1219                                                        root_objectid);
1220                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1221                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1222                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1223                 } else {
1224                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1225                         num_refs += refs_to_add;
1226                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1227                 }
1228         }
1229         btrfs_mark_buffer_dirty(leaf);
1230         ret = 0;
1231 fail:
1232         btrfs_release_path(path);
1233         return ret;
1234 }
1235
1236 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1237                                            struct btrfs_root *root,
1238                                            struct btrfs_path *path,
1239                                            int refs_to_drop)
1240 {
1241         struct btrfs_key key;
1242         struct btrfs_extent_data_ref *ref1 = NULL;
1243         struct btrfs_shared_data_ref *ref2 = NULL;
1244         struct extent_buffer *leaf;
1245         u32 num_refs = 0;
1246         int ret = 0;
1247
1248         leaf = path->nodes[0];
1249         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1250
1251         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1252                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1253                                       struct btrfs_extent_data_ref);
1254                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1255         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1256                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1257                                       struct btrfs_shared_data_ref);
1258                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1259 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1260         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1261                 struct btrfs_extent_ref_v0 *ref0;
1262                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1263                                       struct btrfs_extent_ref_v0);
1264                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1265 #endif
1266         } else {
1267                 BUG();
1268         }
1269
1270         BUG_ON(num_refs < refs_to_drop);
1271         num_refs -= refs_to_drop;
1272
1273         if (num_refs == 0) {
1274                 ret = btrfs_del_item(trans, root, path);
1275         } else {
1276                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1277                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1278                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1279                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1280 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1281                 else {
1282                         struct btrfs_extent_ref_v0 *ref0;
1283                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1284                                         struct btrfs_extent_ref_v0);
1285                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1286                 }
1287 #endif
1288                 btrfs_mark_buffer_dirty(leaf);
1289         }
1290         return ret;
1291 }
1292
1293 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1294                                           struct btrfs_path *path,
1295                                           struct btrfs_extent_inline_ref *iref)
1296 {
1297         struct btrfs_key key;
1298         struct extent_buffer *leaf;
1299         struct btrfs_extent_data_ref *ref1;
1300         struct btrfs_shared_data_ref *ref2;
1301         u32 num_refs = 0;
1302
1303         leaf = path->nodes[0];
1304         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1305         if (iref) {
1306                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1307                     BTRFS_EXTENT_DATA_REF_KEY) {
1308                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1309                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1310                 } else {
1311                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1312                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1313                 }
1314         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1315                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1316                                       struct btrfs_extent_data_ref);
1317                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1318         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1319                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1320                                       struct btrfs_shared_data_ref);
1321                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1322 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1323         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1324                 struct btrfs_extent_ref_v0 *ref0;
1325                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1326                                       struct btrfs_extent_ref_v0);
1327                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1328 #endif
1329         } else {
1330                 WARN_ON(1);
1331         }
1332         return num_refs;
1333 }
1334
1335 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1336                                           struct btrfs_root *root,
1337                                           struct btrfs_path *path,
1338                                           u64 bytenr, u64 parent,
1339                                           u64 root_objectid)
1340 {
1341         struct btrfs_key key;
1342         int ret;
1343
1344         key.objectid = bytenr;
1345         if (parent) {
1346                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1347                 key.offset = parent;
1348         } else {
1349                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1350                 key.offset = root_objectid;
1351         }
1352
1353         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1354         if (ret > 0)
1355                 ret = -ENOENT;
1356 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1357         if (ret == -ENOENT && parent) {
1358                 btrfs_release_path(path);
1359                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1360                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1361                 if (ret > 0)
1362                         ret = -ENOENT;
1363         }
1364 #endif
1365         return ret;
1366 }
1367
1368 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1369                                           struct btrfs_root *root,
1370                                           struct btrfs_path *path,
1371                                           u64 bytenr, u64 parent,
1372                                           u64 root_objectid)
1373 {
1374         struct btrfs_key key;
1375         int ret;
1376
1377         key.objectid = bytenr;
1378         if (parent) {
1379                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1380                 key.offset = parent;
1381         } else {
1382                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1383                 key.offset = root_objectid;
1384         }
1385
1386         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1387         btrfs_release_path(path);
1388         return ret;
1389 }
1390
1391 static inline int extent_ref_type(u64 parent, u64 owner)
1392 {
1393         int type;
1394         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1395                 if (parent > 0)
1396                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1397                 else
1398                         type = BTRFS_TREE_BLOCK_REF_KEY;
1399         } else {
1400                 if (parent > 0)
1401                         type = BTRFS_SHARED_DATA_REF_KEY;
1402                 else
1403                         type = BTRFS_EXTENT_DATA_REF_KEY;
1404         }
1405         return type;
1406 }
1407
1408 static int find_next_key(struct btrfs_path *path, int level,
1409                          struct btrfs_key *key)
1410
1411 {
1412         for (; level < BTRFS_MAX_LEVEL; level++) {
1413                 if (!path->nodes[level])
1414                         break;
1415                 if (path->slots[level] + 1 >=
1416                     btrfs_header_nritems(path->nodes[level]))
1417                         continue;
1418                 if (level == 0)
1419                         btrfs_item_key_to_cpu(path->nodes[level], key,
1420                                               path->slots[level] + 1);
1421                 else
1422                         btrfs_node_key_to_cpu(path->nodes[level], key,
1423                                               path->slots[level] + 1);
1424                 return 0;
1425         }
1426         return 1;
1427 }
1428
1429 /*
1430  * look for inline back ref. if back ref is found, *ref_ret is set
1431  * to the address of inline back ref, and 0 is returned.
1432  *
1433  * if back ref isn't found, *ref_ret is set to the address where it
1434  * should be inserted, and -ENOENT is returned.
1435  *
1436  * if insert is true and there are too many inline back refs, the path
1437  * points to the extent item, and -EAGAIN is returned.
1438  *
1439  * NOTE: inline back refs are ordered in the same way that back ref
1440  *       items in the tree are ordered.
1441  */
1442 static noinline_for_stack
1443 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1444                                  struct btrfs_root *root,
1445                                  struct btrfs_path *path,
1446                                  struct btrfs_extent_inline_ref **ref_ret,
1447                                  u64 bytenr, u64 num_bytes,
1448                                  u64 parent, u64 root_objectid,
1449                                  u64 owner, u64 offset, int insert)
1450 {
1451         struct btrfs_key key;
1452         struct extent_buffer *leaf;
1453         struct btrfs_extent_item *ei;
1454         struct btrfs_extent_inline_ref *iref;
1455         u64 flags;
1456         u64 item_size;
1457         unsigned long ptr;
1458         unsigned long end;
1459         int extra_size;
1460         int type;
1461         int want;
1462         int ret;
1463         int err = 0;
1464
1465         key.objectid = bytenr;
1466         key.type = BTRFS_EXTENT_ITEM_KEY;
1467         key.offset = num_bytes;
1468
1469         want = extent_ref_type(parent, owner);
1470         if (insert) {
1471                 extra_size = btrfs_extent_inline_ref_size(want);
1472                 path->keep_locks = 1;
1473         } else
1474                 extra_size = -1;
1475         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1476         if (ret < 0) {
1477                 err = ret;
1478                 goto out;
1479         }
1480         BUG_ON(ret);
1481
1482         leaf = path->nodes[0];
1483         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1484 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1485         if (item_size < sizeof(*ei)) {
1486                 if (!insert) {
1487                         err = -ENOENT;
1488                         goto out;
1489                 }
1490                 ret = convert_extent_item_v0(trans, root, path, owner,
1491                                              extra_size);
1492                 if (ret < 0) {
1493                         err = ret;
1494                         goto out;
1495                 }
1496                 leaf = path->nodes[0];
1497                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1498         }
1499 #endif
1500         BUG_ON(item_size < sizeof(*ei));
1501
1502         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1503         flags = btrfs_extent_flags(leaf, ei);
1504
1505         ptr = (unsigned long)(ei + 1);
1506         end = (unsigned long)ei + item_size;
1507
1508         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1509                 ptr += sizeof(struct btrfs_tree_block_info);
1510                 BUG_ON(ptr > end);
1511         } else {
1512                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
1513         }
1514
1515         err = -ENOENT;
1516         while (1) {
1517                 if (ptr >= end) {
1518                         WARN_ON(ptr > end);
1519                         break;
1520                 }
1521                 iref = (struct btrfs_extent_inline_ref *)ptr;
1522                 type = btrfs_extent_inline_ref_type(leaf, iref);
1523                 if (want < type)
1524                         break;
1525                 if (want > type) {
1526                         ptr += btrfs_extent_inline_ref_size(type);
1527                         continue;
1528                 }
1529
1530                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1531                         struct btrfs_extent_data_ref *dref;
1532                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1533                         if (match_extent_data_ref(leaf, dref, root_objectid,
1534                                                   owner, offset)) {
1535                                 err = 0;
1536                                 break;
1537                         }
1538                         if (hash_extent_data_ref_item(leaf, dref) <
1539                             hash_extent_data_ref(root_objectid, owner, offset))
1540                                 break;
1541                 } else {
1542                         u64 ref_offset;
1543                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1544                         if (parent > 0) {
1545                                 if (parent == ref_offset) {
1546                                         err = 0;
1547                                         break;
1548                                 }
1549                                 if (ref_offset < parent)
1550                                         break;
1551                         } else {
1552                                 if (root_objectid == ref_offset) {
1553                                         err = 0;
1554                                         break;
1555                                 }
1556                                 if (ref_offset < root_objectid)
1557                                         break;
1558                         }
1559                 }
1560                 ptr += btrfs_extent_inline_ref_size(type);
1561         }
1562         if (err == -ENOENT && insert) {
1563                 if (item_size + extra_size >=
1564                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1565                         err = -EAGAIN;
1566                         goto out;
1567                 }
1568                 /*
1569                  * To add new inline back ref, we have to make sure
1570                  * there is no corresponding back ref item.
1571                  * For simplicity, we just do not add new inline back
1572                  * ref if there is any kind of item for this block
1573                  */
1574                 if (find_next_key(path, 0, &key) == 0 &&
1575                     key.objectid == bytenr &&
1576                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1577                         err = -EAGAIN;
1578                         goto out;
1579                 }
1580         }
1581         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1582 out:
1583         if (insert) {
1584                 path->keep_locks = 0;
1585                 btrfs_unlock_up_safe(path, 1);
1586         }
1587         return err;
1588 }
1589
1590 /*
1591  * helper to add new inline back ref
1592  */
1593 static noinline_for_stack
1594 int setup_inline_extent_backref(struct btrfs_trans_handle *trans,
1595                                 struct btrfs_root *root,
1596                                 struct btrfs_path *path,
1597                                 struct btrfs_extent_inline_ref *iref,
1598                                 u64 parent, u64 root_objectid,
1599                                 u64 owner, u64 offset, int refs_to_add,
1600                                 struct btrfs_delayed_extent_op *extent_op)
1601 {
1602         struct extent_buffer *leaf;
1603         struct btrfs_extent_item *ei;
1604         unsigned long ptr;
1605         unsigned long end;
1606         unsigned long item_offset;
1607         u64 refs;
1608         int size;
1609         int type;
1610         int ret;
1611
1612         leaf = path->nodes[0];
1613         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1614         item_offset = (unsigned long)iref - (unsigned long)ei;
1615
1616         type = extent_ref_type(parent, owner);
1617         size = btrfs_extent_inline_ref_size(type);
1618
1619         ret = btrfs_extend_item(trans, root, path, size);
1620
1621         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1622         refs = btrfs_extent_refs(leaf, ei);
1623         refs += refs_to_add;
1624         btrfs_set_extent_refs(leaf, ei, refs);
1625         if (extent_op)
1626                 __run_delayed_extent_op(extent_op, leaf, ei);
1627
1628         ptr = (unsigned long)ei + item_offset;
1629         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1630         if (ptr < end - size)
1631                 memmove_extent_buffer(leaf, ptr + size, ptr,
1632                                       end - size - ptr);
1633
1634         iref = (struct btrfs_extent_inline_ref *)ptr;
1635         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1636         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1637                 struct btrfs_extent_data_ref *dref;
1638                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1639                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1640                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1641                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1642                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1643         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1644                 struct btrfs_shared_data_ref *sref;
1645                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1646                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1647                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1648         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1649                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1650         } else {
1651                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1652         }
1653         btrfs_mark_buffer_dirty(leaf);
1654         return 0;
1655 }
1656
1657 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1658                                  struct btrfs_root *root,
1659                                  struct btrfs_path *path,
1660                                  struct btrfs_extent_inline_ref **ref_ret,
1661                                  u64 bytenr, u64 num_bytes, u64 parent,
1662                                  u64 root_objectid, u64 owner, u64 offset)
1663 {
1664         int ret;
1665
1666         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1667                                            bytenr, num_bytes, parent,
1668                                            root_objectid, owner, offset, 0);
1669         if (ret != -ENOENT)
1670                 return ret;
1671
1672         btrfs_release_path(path);
1673         *ref_ret = NULL;
1674
1675         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1676                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1677                                             root_objectid);
1678         } else {
1679                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1680                                              root_objectid, owner, offset);
1681         }
1682         return ret;
1683 }
1684
1685 /*
1686  * helper to update/remove inline back ref
1687  */
1688 static noinline_for_stack
1689 int update_inline_extent_backref(struct btrfs_trans_handle *trans,
1690                                  struct btrfs_root *root,
1691                                  struct btrfs_path *path,
1692                                  struct btrfs_extent_inline_ref *iref,
1693                                  int refs_to_mod,
1694                                  struct btrfs_delayed_extent_op *extent_op)
1695 {
1696         struct extent_buffer *leaf;
1697         struct btrfs_extent_item *ei;
1698         struct btrfs_extent_data_ref *dref = NULL;
1699         struct btrfs_shared_data_ref *sref = NULL;
1700         unsigned long ptr;
1701         unsigned long end;
1702         u32 item_size;
1703         int size;
1704         int type;
1705         int ret;
1706         u64 refs;
1707
1708         leaf = path->nodes[0];
1709         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1710         refs = btrfs_extent_refs(leaf, ei);
1711         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1712         refs += refs_to_mod;
1713         btrfs_set_extent_refs(leaf, ei, refs);
1714         if (extent_op)
1715                 __run_delayed_extent_op(extent_op, leaf, ei);
1716
1717         type = btrfs_extent_inline_ref_type(leaf, iref);
1718
1719         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1720                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1721                 refs = btrfs_extent_data_ref_count(leaf, dref);
1722         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1723                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1724                 refs = btrfs_shared_data_ref_count(leaf, sref);
1725         } else {
1726                 refs = 1;
1727                 BUG_ON(refs_to_mod != -1);
1728         }
1729
1730         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1731         refs += refs_to_mod;
1732
1733         if (refs > 0) {
1734                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1735                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1736                 else
1737                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1738         } else {
1739                 size =  btrfs_extent_inline_ref_size(type);
1740                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1741                 ptr = (unsigned long)iref;
1742                 end = (unsigned long)ei + item_size;
1743                 if (ptr + size < end)
1744                         memmove_extent_buffer(leaf, ptr, ptr + size,
1745                                               end - ptr - size);
1746                 item_size -= size;
1747                 ret = btrfs_truncate_item(trans, root, path, item_size, 1);
1748         }
1749         btrfs_mark_buffer_dirty(leaf);
1750         return 0;
1751 }
1752
1753 static noinline_for_stack
1754 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1755                                  struct btrfs_root *root,
1756                                  struct btrfs_path *path,
1757                                  u64 bytenr, u64 num_bytes, u64 parent,
1758                                  u64 root_objectid, u64 owner,
1759                                  u64 offset, int refs_to_add,
1760                                  struct btrfs_delayed_extent_op *extent_op)
1761 {
1762         struct btrfs_extent_inline_ref *iref;
1763         int ret;
1764
1765         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1766                                            bytenr, num_bytes, parent,
1767                                            root_objectid, owner, offset, 1);
1768         if (ret == 0) {
1769                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1770                 ret = update_inline_extent_backref(trans, root, path, iref,
1771                                                    refs_to_add, extent_op);
1772         } else if (ret == -ENOENT) {
1773                 ret = setup_inline_extent_backref(trans, root, path, iref,
1774                                                   parent, root_objectid,
1775                                                   owner, offset, refs_to_add,
1776                                                   extent_op);
1777         }
1778         return ret;
1779 }
1780
1781 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1782                                  struct btrfs_root *root,
1783                                  struct btrfs_path *path,
1784                                  u64 bytenr, u64 parent, u64 root_objectid,
1785                                  u64 owner, u64 offset, int refs_to_add)
1786 {
1787         int ret;
1788         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1789                 BUG_ON(refs_to_add != 1);
1790                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1791                                             parent, root_objectid);
1792         } else {
1793                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1794                                              parent, root_objectid,
1795                                              owner, offset, refs_to_add);
1796         }
1797         return ret;
1798 }
1799
1800 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1801                                  struct btrfs_root *root,
1802                                  struct btrfs_path *path,
1803                                  struct btrfs_extent_inline_ref *iref,
1804                                  int refs_to_drop, int is_data)
1805 {
1806         int ret;
1807
1808         BUG_ON(!is_data && refs_to_drop != 1);
1809         if (iref) {
1810                 ret = update_inline_extent_backref(trans, root, path, iref,
1811                                                    -refs_to_drop, NULL);
1812         } else if (is_data) {
1813                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1814         } else {
1815                 ret = btrfs_del_item(trans, root, path);
1816         }
1817         return ret;
1818 }
1819
1820 static int btrfs_issue_discard(struct block_device *bdev,
1821                                 u64 start, u64 len)
1822 {
1823         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1824 }
1825
1826 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1827                                 u64 num_bytes, u64 *actual_bytes)
1828 {
1829         int ret;
1830         u64 discarded_bytes = 0;
1831         struct btrfs_bio *bbio = NULL;
1832
1833
1834         /* Tell the block device(s) that the sectors can be discarded */
1835         ret = btrfs_map_block(&root->fs_info->mapping_tree, REQ_DISCARD,
1836                               bytenr, &num_bytes, &bbio, 0);
1837         if (!ret) {
1838                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1839                 int i;
1840
1841
1842                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1843                         if (!stripe->dev->can_discard)
1844                                 continue;
1845
1846                         ret = btrfs_issue_discard(stripe->dev->bdev,
1847                                                   stripe->physical,
1848                                                   stripe->length);
1849                         if (!ret)
1850                                 discarded_bytes += stripe->length;
1851                         else if (ret != -EOPNOTSUPP)
1852                                 break;
1853
1854                         /*
1855                          * Just in case we get back EOPNOTSUPP for some reason,
1856                          * just ignore the return value so we don't screw up
1857                          * people calling discard_extent.
1858                          */
1859                         ret = 0;
1860                 }
1861                 kfree(bbio);
1862         }
1863
1864         if (actual_bytes)
1865                 *actual_bytes = discarded_bytes;
1866
1867
1868         return ret;
1869 }
1870
1871 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1872                          struct btrfs_root *root,
1873                          u64 bytenr, u64 num_bytes, u64 parent,
1874                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1875 {
1876         int ret;
1877         struct btrfs_fs_info *fs_info = root->fs_info;
1878
1879         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1880                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1881
1882         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1883                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1884                                         num_bytes,
1885                                         parent, root_objectid, (int)owner,
1886                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1887         } else {
1888                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1889                                         num_bytes,
1890                                         parent, root_objectid, owner, offset,
1891                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1892         }
1893         return ret;
1894 }
1895
1896 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1897                                   struct btrfs_root *root,
1898                                   u64 bytenr, u64 num_bytes,
1899                                   u64 parent, u64 root_objectid,
1900                                   u64 owner, u64 offset, int refs_to_add,
1901                                   struct btrfs_delayed_extent_op *extent_op)
1902 {
1903         struct btrfs_path *path;
1904         struct extent_buffer *leaf;
1905         struct btrfs_extent_item *item;
1906         u64 refs;
1907         int ret;
1908         int err = 0;
1909
1910         path = btrfs_alloc_path();
1911         if (!path)
1912                 return -ENOMEM;
1913
1914         path->reada = 1;
1915         path->leave_spinning = 1;
1916         /* this will setup the path even if it fails to insert the back ref */
1917         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1918                                            path, bytenr, num_bytes, parent,
1919                                            root_objectid, owner, offset,
1920                                            refs_to_add, extent_op);
1921         if (ret == 0)
1922                 goto out;
1923
1924         if (ret != -EAGAIN) {
1925                 err = ret;
1926                 goto out;
1927         }
1928
1929         leaf = path->nodes[0];
1930         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1931         refs = btrfs_extent_refs(leaf, item);
1932         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1933         if (extent_op)
1934                 __run_delayed_extent_op(extent_op, leaf, item);
1935
1936         btrfs_mark_buffer_dirty(leaf);
1937         btrfs_release_path(path);
1938
1939         path->reada = 1;
1940         path->leave_spinning = 1;
1941
1942         /* now insert the actual backref */
1943         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1944                                     path, bytenr, parent, root_objectid,
1945                                     owner, offset, refs_to_add);
1946         BUG_ON(ret);
1947 out:
1948         btrfs_free_path(path);
1949         return err;
1950 }
1951
1952 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1953                                 struct btrfs_root *root,
1954                                 struct btrfs_delayed_ref_node *node,
1955                                 struct btrfs_delayed_extent_op *extent_op,
1956                                 int insert_reserved)
1957 {
1958         int ret = 0;
1959         struct btrfs_delayed_data_ref *ref;
1960         struct btrfs_key ins;
1961         u64 parent = 0;
1962         u64 ref_root = 0;
1963         u64 flags = 0;
1964
1965         ins.objectid = node->bytenr;
1966         ins.offset = node->num_bytes;
1967         ins.type = BTRFS_EXTENT_ITEM_KEY;
1968
1969         ref = btrfs_delayed_node_to_data_ref(node);
1970         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1971                 parent = ref->parent;
1972         else
1973                 ref_root = ref->root;
1974
1975         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1976                 if (extent_op) {
1977                         BUG_ON(extent_op->update_key);
1978                         flags |= extent_op->flags_to_set;
1979                 }
1980                 ret = alloc_reserved_file_extent(trans, root,
1981                                                  parent, ref_root, flags,
1982                                                  ref->objectid, ref->offset,
1983                                                  &ins, node->ref_mod);
1984         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1985                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1986                                              node->num_bytes, parent,
1987                                              ref_root, ref->objectid,
1988                                              ref->offset, node->ref_mod,
1989                                              extent_op);
1990         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1991                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1992                                           node->num_bytes, parent,
1993                                           ref_root, ref->objectid,
1994                                           ref->offset, node->ref_mod,
1995                                           extent_op);
1996         } else {
1997                 BUG();
1998         }
1999         return ret;
2000 }
2001
2002 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2003                                     struct extent_buffer *leaf,
2004                                     struct btrfs_extent_item *ei)
2005 {
2006         u64 flags = btrfs_extent_flags(leaf, ei);
2007         if (extent_op->update_flags) {
2008                 flags |= extent_op->flags_to_set;
2009                 btrfs_set_extent_flags(leaf, ei, flags);
2010         }
2011
2012         if (extent_op->update_key) {
2013                 struct btrfs_tree_block_info *bi;
2014                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2015                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2016                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2017         }
2018 }
2019
2020 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2021                                  struct btrfs_root *root,
2022                                  struct btrfs_delayed_ref_node *node,
2023                                  struct btrfs_delayed_extent_op *extent_op)
2024 {
2025         struct btrfs_key key;
2026         struct btrfs_path *path;
2027         struct btrfs_extent_item *ei;
2028         struct extent_buffer *leaf;
2029         u32 item_size;
2030         int ret;
2031         int err = 0;
2032
2033         path = btrfs_alloc_path();
2034         if (!path)
2035                 return -ENOMEM;
2036
2037         key.objectid = node->bytenr;
2038         key.type = BTRFS_EXTENT_ITEM_KEY;
2039         key.offset = node->num_bytes;
2040
2041         path->reada = 1;
2042         path->leave_spinning = 1;
2043         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2044                                 path, 0, 1);
2045         if (ret < 0) {
2046                 err = ret;
2047                 goto out;
2048         }
2049         if (ret > 0) {
2050                 err = -EIO;
2051                 goto out;
2052         }
2053
2054         leaf = path->nodes[0];
2055         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2056 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2057         if (item_size < sizeof(*ei)) {
2058                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2059                                              path, (u64)-1, 0);
2060                 if (ret < 0) {
2061                         err = ret;
2062                         goto out;
2063                 }
2064                 leaf = path->nodes[0];
2065                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2066         }
2067 #endif
2068         BUG_ON(item_size < sizeof(*ei));
2069         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2070         __run_delayed_extent_op(extent_op, leaf, ei);
2071
2072         btrfs_mark_buffer_dirty(leaf);
2073 out:
2074         btrfs_free_path(path);
2075         return err;
2076 }
2077
2078 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2079                                 struct btrfs_root *root,
2080                                 struct btrfs_delayed_ref_node *node,
2081                                 struct btrfs_delayed_extent_op *extent_op,
2082                                 int insert_reserved)
2083 {
2084         int ret = 0;
2085         struct btrfs_delayed_tree_ref *ref;
2086         struct btrfs_key ins;
2087         u64 parent = 0;
2088         u64 ref_root = 0;
2089
2090         ins.objectid = node->bytenr;
2091         ins.offset = node->num_bytes;
2092         ins.type = BTRFS_EXTENT_ITEM_KEY;
2093
2094         ref = btrfs_delayed_node_to_tree_ref(node);
2095         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2096                 parent = ref->parent;
2097         else
2098                 ref_root = ref->root;
2099
2100         BUG_ON(node->ref_mod != 1);
2101         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2102                 BUG_ON(!extent_op || !extent_op->update_flags ||
2103                        !extent_op->update_key);
2104                 ret = alloc_reserved_tree_block(trans, root,
2105                                                 parent, ref_root,
2106                                                 extent_op->flags_to_set,
2107                                                 &extent_op->key,
2108                                                 ref->level, &ins);
2109         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2110                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2111                                              node->num_bytes, parent, ref_root,
2112                                              ref->level, 0, 1, extent_op);
2113         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2114                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2115                                           node->num_bytes, parent, ref_root,
2116                                           ref->level, 0, 1, extent_op);
2117         } else {
2118                 BUG();
2119         }
2120         return ret;
2121 }
2122
2123 /* helper function to actually process a single delayed ref entry */
2124 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2125                                struct btrfs_root *root,
2126                                struct btrfs_delayed_ref_node *node,
2127                                struct btrfs_delayed_extent_op *extent_op,
2128                                int insert_reserved)
2129 {
2130         int ret;
2131         if (btrfs_delayed_ref_is_head(node)) {
2132                 struct btrfs_delayed_ref_head *head;
2133                 /*
2134                  * we've hit the end of the chain and we were supposed
2135                  * to insert this extent into the tree.  But, it got
2136                  * deleted before we ever needed to insert it, so all
2137                  * we have to do is clean up the accounting
2138                  */
2139                 BUG_ON(extent_op);
2140                 head = btrfs_delayed_node_to_head(node);
2141                 if (insert_reserved) {
2142                         btrfs_pin_extent(root, node->bytenr,
2143                                          node->num_bytes, 1);
2144                         if (head->is_data) {
2145                                 ret = btrfs_del_csums(trans, root,
2146                                                       node->bytenr,
2147                                                       node->num_bytes);
2148                                 BUG_ON(ret);
2149                         }
2150                 }
2151                 mutex_unlock(&head->mutex);
2152                 return 0;
2153         }
2154
2155         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2156             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2157                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2158                                            insert_reserved);
2159         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2160                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2161                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2162                                            insert_reserved);
2163         else
2164                 BUG();
2165         return ret;
2166 }
2167
2168 static noinline struct btrfs_delayed_ref_node *
2169 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2170 {
2171         struct rb_node *node;
2172         struct btrfs_delayed_ref_node *ref;
2173         int action = BTRFS_ADD_DELAYED_REF;
2174 again:
2175         /*
2176          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2177          * this prevents ref count from going down to zero when
2178          * there still are pending delayed ref.
2179          */
2180         node = rb_prev(&head->node.rb_node);
2181         while (1) {
2182                 if (!node)
2183                         break;
2184                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2185                                 rb_node);
2186                 if (ref->bytenr != head->node.bytenr)
2187                         break;
2188                 if (ref->action == action)
2189                         return ref;
2190                 node = rb_prev(node);
2191         }
2192         if (action == BTRFS_ADD_DELAYED_REF) {
2193                 action = BTRFS_DROP_DELAYED_REF;
2194                 goto again;
2195         }
2196         return NULL;
2197 }
2198
2199 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2200                                        struct btrfs_root *root,
2201                                        struct list_head *cluster)
2202 {
2203         struct btrfs_delayed_ref_root *delayed_refs;
2204         struct btrfs_delayed_ref_node *ref;
2205         struct btrfs_delayed_ref_head *locked_ref = NULL;
2206         struct btrfs_delayed_extent_op *extent_op;
2207         int ret;
2208         int count = 0;
2209         int must_insert_reserved = 0;
2210
2211         delayed_refs = &trans->transaction->delayed_refs;
2212         while (1) {
2213                 if (!locked_ref) {
2214                         /* pick a new head ref from the cluster list */
2215                         if (list_empty(cluster))
2216                                 break;
2217
2218                         locked_ref = list_entry(cluster->next,
2219                                      struct btrfs_delayed_ref_head, cluster);
2220
2221                         /* grab the lock that says we are going to process
2222                          * all the refs for this head */
2223                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2224
2225                         /*
2226                          * we may have dropped the spin lock to get the head
2227                          * mutex lock, and that might have given someone else
2228                          * time to free the head.  If that's true, it has been
2229                          * removed from our list and we can move on.
2230                          */
2231                         if (ret == -EAGAIN) {
2232                                 locked_ref = NULL;
2233                                 count++;
2234                                 continue;
2235                         }
2236                 }
2237
2238                 /*
2239                  * locked_ref is the head node, so we have to go one
2240                  * node back for any delayed ref updates
2241                  */
2242                 ref = select_delayed_ref(locked_ref);
2243
2244                 if (ref && ref->seq &&
2245                     btrfs_check_delayed_seq(delayed_refs, ref->seq)) {
2246                         /*
2247                          * there are still refs with lower seq numbers in the
2248                          * process of being added. Don't run this ref yet.
2249                          */
2250                         list_del_init(&locked_ref->cluster);
2251                         mutex_unlock(&locked_ref->mutex);
2252                         locked_ref = NULL;
2253                         delayed_refs->num_heads_ready++;
2254                         spin_unlock(&delayed_refs->lock);
2255                         cond_resched();
2256                         spin_lock(&delayed_refs->lock);
2257                         continue;
2258                 }
2259
2260                 /*
2261                  * record the must insert reserved flag before we
2262                  * drop the spin lock.
2263                  */
2264                 must_insert_reserved = locked_ref->must_insert_reserved;
2265                 locked_ref->must_insert_reserved = 0;
2266
2267                 extent_op = locked_ref->extent_op;
2268                 locked_ref->extent_op = NULL;
2269
2270                 if (!ref) {
2271                         /* All delayed refs have been processed, Go ahead
2272                          * and send the head node to run_one_delayed_ref,
2273                          * so that any accounting fixes can happen
2274                          */
2275                         ref = &locked_ref->node;
2276
2277                         if (extent_op && must_insert_reserved) {
2278                                 kfree(extent_op);
2279                                 extent_op = NULL;
2280                         }
2281
2282                         if (extent_op) {
2283                                 spin_unlock(&delayed_refs->lock);
2284
2285                                 ret = run_delayed_extent_op(trans, root,
2286                                                             ref, extent_op);
2287                                 BUG_ON(ret);
2288                                 kfree(extent_op);
2289
2290                                 goto next;
2291                         }
2292
2293                         list_del_init(&locked_ref->cluster);
2294                         locked_ref = NULL;
2295                 }
2296
2297                 ref->in_tree = 0;
2298                 rb_erase(&ref->rb_node, &delayed_refs->root);
2299                 delayed_refs->num_entries--;
2300                 /*
2301                  * we modified num_entries, but as we're currently running
2302                  * delayed refs, skip
2303                  *     wake_up(&delayed_refs->seq_wait);
2304                  * here.
2305                  */
2306                 spin_unlock(&delayed_refs->lock);
2307
2308                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2309                                           must_insert_reserved);
2310                 BUG_ON(ret);
2311
2312                 btrfs_put_delayed_ref(ref);
2313                 kfree(extent_op);
2314                 count++;
2315 next:
2316                 do_chunk_alloc(trans, root->fs_info->extent_root,
2317                                2 * 1024 * 1024,
2318                                btrfs_get_alloc_profile(root, 0),
2319                                CHUNK_ALLOC_NO_FORCE);
2320                 cond_resched();
2321                 spin_lock(&delayed_refs->lock);
2322         }
2323         return count;
2324 }
2325
2326
2327 static void wait_for_more_refs(struct btrfs_delayed_ref_root *delayed_refs,
2328                         unsigned long num_refs)
2329 {
2330         struct list_head *first_seq = delayed_refs->seq_head.next;
2331
2332         spin_unlock(&delayed_refs->lock);
2333         pr_debug("waiting for more refs (num %ld, first %p)\n",
2334                  num_refs, first_seq);
2335         wait_event(delayed_refs->seq_wait,
2336                    num_refs != delayed_refs->num_entries ||
2337                    delayed_refs->seq_head.next != first_seq);
2338         pr_debug("done waiting for more refs (num %ld, first %p)\n",
2339                  delayed_refs->num_entries, delayed_refs->seq_head.next);
2340         spin_lock(&delayed_refs->lock);
2341 }
2342
2343 /*
2344  * this starts processing the delayed reference count updates and
2345  * extent insertions we have queued up so far.  count can be
2346  * 0, which means to process everything in the tree at the start
2347  * of the run (but not newly added entries), or it can be some target
2348  * number you'd like to process.
2349  */
2350 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2351                            struct btrfs_root *root, unsigned long count)
2352 {
2353         struct rb_node *node;
2354         struct btrfs_delayed_ref_root *delayed_refs;
2355         struct btrfs_delayed_ref_node *ref;
2356         struct list_head cluster;
2357         int ret;
2358         u64 delayed_start;
2359         int run_all = count == (unsigned long)-1;
2360         int run_most = 0;
2361         unsigned long num_refs = 0;
2362         int consider_waiting;
2363
2364         if (root == root->fs_info->extent_root)
2365                 root = root->fs_info->tree_root;
2366
2367         do_chunk_alloc(trans, root->fs_info->extent_root,
2368                        2 * 1024 * 1024, btrfs_get_alloc_profile(root, 0),
2369                        CHUNK_ALLOC_NO_FORCE);
2370
2371         delayed_refs = &trans->transaction->delayed_refs;
2372         INIT_LIST_HEAD(&cluster);
2373 again:
2374         consider_waiting = 0;
2375         spin_lock(&delayed_refs->lock);
2376         if (count == 0) {
2377                 count = delayed_refs->num_entries * 2;
2378                 run_most = 1;
2379         }
2380         while (1) {
2381                 if (!(run_all || run_most) &&
2382                     delayed_refs->num_heads_ready < 64)
2383                         break;
2384
2385                 /*
2386                  * go find something we can process in the rbtree.  We start at
2387                  * the beginning of the tree, and then build a cluster
2388                  * of refs to process starting at the first one we are able to
2389                  * lock
2390                  */
2391                 delayed_start = delayed_refs->run_delayed_start;
2392                 ret = btrfs_find_ref_cluster(trans, &cluster,
2393                                              delayed_refs->run_delayed_start);
2394                 if (ret)
2395                         break;
2396
2397                 if (delayed_start >= delayed_refs->run_delayed_start) {
2398                         if (consider_waiting == 0) {
2399                                 /*
2400                                  * btrfs_find_ref_cluster looped. let's do one
2401                                  * more cycle. if we don't run any delayed ref
2402                                  * during that cycle (because we can't because
2403                                  * all of them are blocked) and if the number of
2404                                  * refs doesn't change, we avoid busy waiting.
2405                                  */
2406                                 consider_waiting = 1;
2407                                 num_refs = delayed_refs->num_entries;
2408                         } else {
2409                                 wait_for_more_refs(delayed_refs, num_refs);
2410                                 /*
2411                                  * after waiting, things have changed. we
2412                                  * dropped the lock and someone else might have
2413                                  * run some refs, built new clusters and so on.
2414                                  * therefore, we restart staleness detection.
2415                                  */
2416                                 consider_waiting = 0;
2417                         }
2418                 }
2419
2420                 ret = run_clustered_refs(trans, root, &cluster);
2421                 BUG_ON(ret < 0);
2422
2423                 count -= min_t(unsigned long, ret, count);
2424
2425                 if (count == 0)
2426                         break;
2427
2428                 if (ret || delayed_refs->run_delayed_start == 0) {
2429                         /* refs were run, let's reset staleness detection */
2430                         consider_waiting = 0;
2431                 }
2432         }
2433
2434         if (run_all) {
2435                 node = rb_first(&delayed_refs->root);
2436                 if (!node)
2437                         goto out;
2438                 count = (unsigned long)-1;
2439
2440                 while (node) {
2441                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2442                                        rb_node);
2443                         if (btrfs_delayed_ref_is_head(ref)) {
2444                                 struct btrfs_delayed_ref_head *head;
2445
2446                                 head = btrfs_delayed_node_to_head(ref);
2447                                 atomic_inc(&ref->refs);
2448
2449                                 spin_unlock(&delayed_refs->lock);
2450                                 /*
2451                                  * Mutex was contended, block until it's
2452                                  * released and try again
2453                                  */
2454                                 mutex_lock(&head->mutex);
2455                                 mutex_unlock(&head->mutex);
2456
2457                                 btrfs_put_delayed_ref(ref);
2458                                 cond_resched();
2459                                 goto again;
2460                         }
2461                         node = rb_next(node);
2462                 }
2463                 spin_unlock(&delayed_refs->lock);
2464                 schedule_timeout(1);
2465                 goto again;
2466         }
2467 out:
2468         spin_unlock(&delayed_refs->lock);
2469         return 0;
2470 }
2471
2472 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2473                                 struct btrfs_root *root,
2474                                 u64 bytenr, u64 num_bytes, u64 flags,
2475                                 int is_data)
2476 {
2477         struct btrfs_delayed_extent_op *extent_op;
2478         int ret;
2479
2480         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2481         if (!extent_op)
2482                 return -ENOMEM;
2483
2484         extent_op->flags_to_set = flags;
2485         extent_op->update_flags = 1;
2486         extent_op->update_key = 0;
2487         extent_op->is_data = is_data ? 1 : 0;
2488
2489         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2490                                           num_bytes, extent_op);
2491         if (ret)
2492                 kfree(extent_op);
2493         return ret;
2494 }
2495
2496 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2497                                       struct btrfs_root *root,
2498                                       struct btrfs_path *path,
2499                                       u64 objectid, u64 offset, u64 bytenr)
2500 {
2501         struct btrfs_delayed_ref_head *head;
2502         struct btrfs_delayed_ref_node *ref;
2503         struct btrfs_delayed_data_ref *data_ref;
2504         struct btrfs_delayed_ref_root *delayed_refs;
2505         struct rb_node *node;
2506         int ret = 0;
2507
2508         ret = -ENOENT;
2509         delayed_refs = &trans->transaction->delayed_refs;
2510         spin_lock(&delayed_refs->lock);
2511         head = btrfs_find_delayed_ref_head(trans, bytenr);
2512         if (!head)
2513                 goto out;
2514
2515         if (!mutex_trylock(&head->mutex)) {
2516                 atomic_inc(&head->node.refs);
2517                 spin_unlock(&delayed_refs->lock);
2518
2519                 btrfs_release_path(path);
2520
2521                 /*
2522                  * Mutex was contended, block until it's released and let
2523                  * caller try again
2524                  */
2525                 mutex_lock(&head->mutex);
2526                 mutex_unlock(&head->mutex);
2527                 btrfs_put_delayed_ref(&head->node);
2528                 return -EAGAIN;
2529         }
2530
2531         node = rb_prev(&head->node.rb_node);
2532         if (!node)
2533                 goto out_unlock;
2534
2535         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2536
2537         if (ref->bytenr != bytenr)
2538                 goto out_unlock;
2539
2540         ret = 1;
2541         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2542                 goto out_unlock;
2543
2544         data_ref = btrfs_delayed_node_to_data_ref(ref);
2545
2546         node = rb_prev(node);
2547         if (node) {
2548                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2549                 if (ref->bytenr == bytenr)
2550                         goto out_unlock;
2551         }
2552
2553         if (data_ref->root != root->root_key.objectid ||
2554             data_ref->objectid != objectid || data_ref->offset != offset)
2555                 goto out_unlock;
2556
2557         ret = 0;
2558 out_unlock:
2559         mutex_unlock(&head->mutex);
2560 out:
2561         spin_unlock(&delayed_refs->lock);
2562         return ret;
2563 }
2564
2565 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2566                                         struct btrfs_root *root,
2567                                         struct btrfs_path *path,
2568                                         u64 objectid, u64 offset, u64 bytenr)
2569 {
2570         struct btrfs_root *extent_root = root->fs_info->extent_root;
2571         struct extent_buffer *leaf;
2572         struct btrfs_extent_data_ref *ref;
2573         struct btrfs_extent_inline_ref *iref;
2574         struct btrfs_extent_item *ei;
2575         struct btrfs_key key;
2576         u32 item_size;
2577         int ret;
2578
2579         key.objectid = bytenr;
2580         key.offset = (u64)-1;
2581         key.type = BTRFS_EXTENT_ITEM_KEY;
2582
2583         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2584         if (ret < 0)
2585                 goto out;
2586         BUG_ON(ret == 0);
2587
2588         ret = -ENOENT;
2589         if (path->slots[0] == 0)
2590                 goto out;
2591
2592         path->slots[0]--;
2593         leaf = path->nodes[0];
2594         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2595
2596         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2597                 goto out;
2598
2599         ret = 1;
2600         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2601 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2602         if (item_size < sizeof(*ei)) {
2603                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2604                 goto out;
2605         }
2606 #endif
2607         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2608
2609         if (item_size != sizeof(*ei) +
2610             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2611                 goto out;
2612
2613         if (btrfs_extent_generation(leaf, ei) <=
2614             btrfs_root_last_snapshot(&root->root_item))
2615                 goto out;
2616
2617         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2618         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2619             BTRFS_EXTENT_DATA_REF_KEY)
2620                 goto out;
2621
2622         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2623         if (btrfs_extent_refs(leaf, ei) !=
2624             btrfs_extent_data_ref_count(leaf, ref) ||
2625             btrfs_extent_data_ref_root(leaf, ref) !=
2626             root->root_key.objectid ||
2627             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2628             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2629                 goto out;
2630
2631         ret = 0;
2632 out:
2633         return ret;
2634 }
2635
2636 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2637                           struct btrfs_root *root,
2638                           u64 objectid, u64 offset, u64 bytenr)
2639 {
2640         struct btrfs_path *path;
2641         int ret;
2642         int ret2;
2643
2644         path = btrfs_alloc_path();
2645         if (!path)
2646                 return -ENOENT;
2647
2648         do {
2649                 ret = check_committed_ref(trans, root, path, objectid,
2650                                           offset, bytenr);
2651                 if (ret && ret != -ENOENT)
2652                         goto out;
2653
2654                 ret2 = check_delayed_ref(trans, root, path, objectid,
2655                                          offset, bytenr);
2656         } while (ret2 == -EAGAIN);
2657
2658         if (ret2 && ret2 != -ENOENT) {
2659                 ret = ret2;
2660                 goto out;
2661         }
2662
2663         if (ret != -ENOENT || ret2 != -ENOENT)
2664                 ret = 0;
2665 out:
2666         btrfs_free_path(path);
2667         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2668                 WARN_ON(ret > 0);
2669         return ret;
2670 }
2671
2672 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2673                            struct btrfs_root *root,
2674                            struct extent_buffer *buf,
2675                            int full_backref, int inc, int for_cow)
2676 {
2677         u64 bytenr;
2678         u64 num_bytes;
2679         u64 parent;
2680         u64 ref_root;
2681         u32 nritems;
2682         struct btrfs_key key;
2683         struct btrfs_file_extent_item *fi;
2684         int i;
2685         int level;
2686         int ret = 0;
2687         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2688                             u64, u64, u64, u64, u64, u64, int);
2689
2690         ref_root = btrfs_header_owner(buf);
2691         nritems = btrfs_header_nritems(buf);
2692         level = btrfs_header_level(buf);
2693
2694         if (!root->ref_cows && level == 0)
2695                 return 0;
2696
2697         if (inc)
2698                 process_func = btrfs_inc_extent_ref;
2699         else
2700                 process_func = btrfs_free_extent;
2701
2702         if (full_backref)
2703                 parent = buf->start;
2704         else
2705                 parent = 0;
2706
2707         for (i = 0; i < nritems; i++) {
2708                 if (level == 0) {
2709                         btrfs_item_key_to_cpu(buf, &key, i);
2710                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2711                                 continue;
2712                         fi = btrfs_item_ptr(buf, i,
2713                                             struct btrfs_file_extent_item);
2714                         if (btrfs_file_extent_type(buf, fi) ==
2715                             BTRFS_FILE_EXTENT_INLINE)
2716                                 continue;
2717                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2718                         if (bytenr == 0)
2719                                 continue;
2720
2721                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2722                         key.offset -= btrfs_file_extent_offset(buf, fi);
2723                         ret = process_func(trans, root, bytenr, num_bytes,
2724                                            parent, ref_root, key.objectid,
2725                                            key.offset, for_cow);
2726                         if (ret)
2727                                 goto fail;
2728                 } else {
2729                         bytenr = btrfs_node_blockptr(buf, i);
2730                         num_bytes = btrfs_level_size(root, level - 1);
2731                         ret = process_func(trans, root, bytenr, num_bytes,
2732                                            parent, ref_root, level - 1, 0,
2733                                            for_cow);
2734                         if (ret)
2735                                 goto fail;
2736                 }
2737         }
2738         return 0;
2739 fail:
2740         BUG();
2741         return ret;
2742 }
2743
2744 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2745                   struct extent_buffer *buf, int full_backref, int for_cow)
2746 {
2747         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
2748 }
2749
2750 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2751                   struct extent_buffer *buf, int full_backref, int for_cow)
2752 {
2753         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
2754 }
2755
2756 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2757                                  struct btrfs_root *root,
2758                                  struct btrfs_path *path,
2759                                  struct btrfs_block_group_cache *cache)
2760 {
2761         int ret;
2762         struct btrfs_root *extent_root = root->fs_info->extent_root;
2763         unsigned long bi;
2764         struct extent_buffer *leaf;
2765
2766         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2767         if (ret < 0)
2768                 goto fail;
2769         BUG_ON(ret);
2770
2771         leaf = path->nodes[0];
2772         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2773         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2774         btrfs_mark_buffer_dirty(leaf);
2775         btrfs_release_path(path);
2776 fail:
2777         if (ret)
2778                 return ret;
2779         return 0;
2780
2781 }
2782
2783 static struct btrfs_block_group_cache *
2784 next_block_group(struct btrfs_root *root,
2785                  struct btrfs_block_group_cache *cache)
2786 {
2787         struct rb_node *node;
2788         spin_lock(&root->fs_info->block_group_cache_lock);
2789         node = rb_next(&cache->cache_node);
2790         btrfs_put_block_group(cache);
2791         if (node) {
2792                 cache = rb_entry(node, struct btrfs_block_group_cache,
2793                                  cache_node);
2794                 btrfs_get_block_group(cache);
2795         } else
2796                 cache = NULL;
2797         spin_unlock(&root->fs_info->block_group_cache_lock);
2798         return cache;
2799 }
2800
2801 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2802                             struct btrfs_trans_handle *trans,
2803                             struct btrfs_path *path)
2804 {
2805         struct btrfs_root *root = block_group->fs_info->tree_root;
2806         struct inode *inode = NULL;
2807         u64 alloc_hint = 0;
2808         int dcs = BTRFS_DC_ERROR;
2809         int num_pages = 0;
2810         int retries = 0;
2811         int ret = 0;
2812
2813         /*
2814          * If this block group is smaller than 100 megs don't bother caching the
2815          * block group.
2816          */
2817         if (block_group->key.offset < (100 * 1024 * 1024)) {
2818                 spin_lock(&block_group->lock);
2819                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2820                 spin_unlock(&block_group->lock);
2821                 return 0;
2822         }
2823
2824 again:
2825         inode = lookup_free_space_inode(root, block_group, path);
2826         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2827                 ret = PTR_ERR(inode);
2828                 btrfs_release_path(path);
2829                 goto out;
2830         }
2831
2832         if (IS_ERR(inode)) {
2833                 BUG_ON(retries);
2834                 retries++;
2835
2836                 if (block_group->ro)
2837                         goto out_free;
2838
2839                 ret = create_free_space_inode(root, trans, block_group, path);
2840                 if (ret)
2841                         goto out_free;
2842                 goto again;
2843         }
2844
2845         /* We've already setup this transaction, go ahead and exit */
2846         if (block_group->cache_generation == trans->transid &&
2847             i_size_read(inode)) {
2848                 dcs = BTRFS_DC_SETUP;
2849                 goto out_put;
2850         }
2851
2852         /*
2853          * We want to set the generation to 0, that way if anything goes wrong
2854          * from here on out we know not to trust this cache when we load up next
2855          * time.
2856          */
2857         BTRFS_I(inode)->generation = 0;
2858         ret = btrfs_update_inode(trans, root, inode);
2859         WARN_ON(ret);
2860
2861         if (i_size_read(inode) > 0) {
2862                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2863                                                       inode);
2864                 if (ret)
2865                         goto out_put;
2866         }
2867
2868         spin_lock(&block_group->lock);
2869         if (block_group->cached != BTRFS_CACHE_FINISHED) {
2870                 /* We're not cached, don't bother trying to write stuff out */
2871                 dcs = BTRFS_DC_WRITTEN;
2872                 spin_unlock(&block_group->lock);
2873                 goto out_put;
2874         }
2875         spin_unlock(&block_group->lock);
2876
2877         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2878         if (!num_pages)
2879                 num_pages = 1;
2880
2881         /*
2882          * Just to make absolutely sure we have enough space, we're going to
2883          * preallocate 12 pages worth of space for each block group.  In
2884          * practice we ought to use at most 8, but we need extra space so we can
2885          * add our header and have a terminator between the extents and the
2886          * bitmaps.
2887          */
2888         num_pages *= 16;
2889         num_pages *= PAGE_CACHE_SIZE;
2890
2891         ret = btrfs_check_data_free_space(inode, num_pages);
2892         if (ret)
2893                 goto out_put;
2894
2895         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2896                                               num_pages, num_pages,
2897                                               &alloc_hint);
2898         if (!ret)
2899                 dcs = BTRFS_DC_SETUP;
2900         btrfs_free_reserved_data_space(inode, num_pages);
2901
2902 out_put:
2903         iput(inode);
2904 out_free:
2905         btrfs_release_path(path);
2906 out:
2907         spin_lock(&block_group->lock);
2908         if (!ret && dcs == BTRFS_DC_SETUP)
2909                 block_group->cache_generation = trans->transid;
2910         block_group->disk_cache_state = dcs;
2911         spin_unlock(&block_group->lock);
2912
2913         return ret;
2914 }
2915
2916 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2917                                    struct btrfs_root *root)
2918 {
2919         struct btrfs_block_group_cache *cache;
2920         int err = 0;
2921         struct btrfs_path *path;
2922         u64 last = 0;
2923
2924         path = btrfs_alloc_path();
2925         if (!path)
2926                 return -ENOMEM;
2927
2928 again:
2929         while (1) {
2930                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2931                 while (cache) {
2932                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2933                                 break;
2934                         cache = next_block_group(root, cache);
2935                 }
2936                 if (!cache) {
2937                         if (last == 0)
2938                                 break;
2939                         last = 0;
2940                         continue;
2941                 }
2942                 err = cache_save_setup(cache, trans, path);
2943                 last = cache->key.objectid + cache->key.offset;
2944                 btrfs_put_block_group(cache);
2945         }
2946
2947         while (1) {
2948                 if (last == 0) {
2949                         err = btrfs_run_delayed_refs(trans, root,
2950                                                      (unsigned long)-1);
2951                         BUG_ON(err);
2952                 }
2953
2954                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2955                 while (cache) {
2956                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
2957                                 btrfs_put_block_group(cache);
2958                                 goto again;
2959                         }
2960
2961                         if (cache->dirty)
2962                                 break;
2963                         cache = next_block_group(root, cache);
2964                 }
2965                 if (!cache) {
2966                         if (last == 0)
2967                                 break;
2968                         last = 0;
2969                         continue;
2970                 }
2971
2972                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
2973                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
2974                 cache->dirty = 0;
2975                 last = cache->key.objectid + cache->key.offset;
2976
2977                 err = write_one_cache_group(trans, root, path, cache);
2978                 BUG_ON(err);
2979                 btrfs_put_block_group(cache);
2980         }
2981
2982         while (1) {
2983                 /*
2984                  * I don't think this is needed since we're just marking our
2985                  * preallocated extent as written, but just in case it can't
2986                  * hurt.
2987                  */
2988                 if (last == 0) {
2989                         err = btrfs_run_delayed_refs(trans, root,
2990                                                      (unsigned long)-1);
2991                         BUG_ON(err);
2992                 }
2993
2994                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2995                 while (cache) {
2996                         /*
2997                          * Really this shouldn't happen, but it could if we
2998                          * couldn't write the entire preallocated extent and
2999                          * splitting the extent resulted in a new block.
3000                          */
3001                         if (cache->dirty) {
3002                                 btrfs_put_block_group(cache);
3003                                 goto again;
3004                         }
3005                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3006                                 break;
3007                         cache = next_block_group(root, cache);
3008                 }
3009                 if (!cache) {
3010                         if (last == 0)
3011                                 break;
3012                         last = 0;
3013                         continue;
3014                 }
3015
3016                 btrfs_write_out_cache(root, trans, cache, path);
3017
3018                 /*
3019                  * If we didn't have an error then the cache state is still
3020                  * NEED_WRITE, so we can set it to WRITTEN.
3021                  */
3022                 if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3023                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3024                 last = cache->key.objectid + cache->key.offset;
3025                 btrfs_put_block_group(cache);
3026         }
3027
3028         btrfs_free_path(path);
3029         return 0;
3030 }
3031
3032 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3033 {
3034         struct btrfs_block_group_cache *block_group;
3035         int readonly = 0;
3036
3037         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3038         if (!block_group || block_group->ro)
3039                 readonly = 1;
3040         if (block_group)
3041                 btrfs_put_block_group(block_group);
3042         return readonly;
3043 }
3044
3045 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3046                              u64 total_bytes, u64 bytes_used,
3047                              struct btrfs_space_info **space_info)
3048 {
3049         struct btrfs_space_info *found;
3050         int i;
3051         int factor;
3052
3053         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3054                      BTRFS_BLOCK_GROUP_RAID10))
3055                 factor = 2;
3056         else
3057                 factor = 1;
3058
3059         found = __find_space_info(info, flags);
3060         if (found) {
3061                 spin_lock(&found->lock);
3062                 found->total_bytes += total_bytes;
3063                 found->disk_total += total_bytes * factor;
3064                 found->bytes_used += bytes_used;
3065                 found->disk_used += bytes_used * factor;
3066                 found->full = 0;
3067                 spin_unlock(&found->lock);
3068                 *space_info = found;
3069                 return 0;
3070         }
3071         found = kzalloc(sizeof(*found), GFP_NOFS);
3072         if (!found)
3073                 return -ENOMEM;
3074
3075         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3076                 INIT_LIST_HEAD(&found->block_groups[i]);
3077         init_rwsem(&found->groups_sem);
3078         spin_lock_init(&found->lock);
3079         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3080         found->total_bytes = total_bytes;
3081         found->disk_total = total_bytes * factor;
3082         found->bytes_used = bytes_used;
3083         found->disk_used = bytes_used * factor;
3084         found->bytes_pinned = 0;
3085         found->bytes_reserved = 0;
3086         found->bytes_readonly = 0;
3087         found->bytes_may_use = 0;
3088         found->full = 0;
3089         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3090         found->chunk_alloc = 0;
3091         found->flush = 0;
3092         init_waitqueue_head(&found->wait);
3093         *space_info = found;
3094         list_add_rcu(&found->list, &info->space_info);
3095         return 0;
3096 }
3097
3098 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3099 {
3100         u64 extra_flags = flags & BTRFS_BLOCK_GROUP_PROFILE_MASK;
3101
3102         /* chunk -> extended profile */
3103         if (extra_flags == 0)
3104                 extra_flags = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3105
3106         if (flags & BTRFS_BLOCK_GROUP_DATA)
3107                 fs_info->avail_data_alloc_bits |= extra_flags;
3108         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3109                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3110         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3111                 fs_info->avail_system_alloc_bits |= extra_flags;
3112 }
3113
3114 /*
3115  * @flags: available profiles in extended format (see ctree.h)
3116  *
3117  * Returns reduced profile in chunk format.  If profile changing is in
3118  * progress (either running or paused) picks the target profile (if it's
3119  * already available), otherwise falls back to plain reducing.
3120  */
3121 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3122 {
3123         /*
3124          * we add in the count of missing devices because we want
3125          * to make sure that any RAID levels on a degraded FS
3126          * continue to be honored.
3127          */
3128         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3129                 root->fs_info->fs_devices->missing_devices;
3130
3131         /* pick restriper's target profile if it's available */
3132         spin_lock(&root->fs_info->balance_lock);
3133         if (root->fs_info->balance_ctl) {
3134                 struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
3135                 u64 tgt = 0;
3136
3137                 if ((flags & BTRFS_BLOCK_GROUP_DATA) &&
3138                     (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3139                     (flags & bctl->data.target)) {
3140                         tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3141                 } else if ((flags & BTRFS_BLOCK_GROUP_SYSTEM) &&
3142                            (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3143                            (flags & bctl->sys.target)) {
3144                         tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3145                 } else if ((flags & BTRFS_BLOCK_GROUP_METADATA) &&
3146                            (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3147                            (flags & bctl->meta.target)) {
3148                         tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3149                 }
3150
3151                 if (tgt) {
3152                         spin_unlock(&root->fs_info->balance_lock);
3153                         flags = tgt;
3154                         goto out;
3155                 }
3156         }
3157         spin_unlock(&root->fs_info->balance_lock);
3158
3159         if (num_devices == 1)
3160                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
3161         if (num_devices < 4)
3162                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3163
3164         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
3165             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3166                       BTRFS_BLOCK_GROUP_RAID10))) {
3167                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
3168         }
3169
3170         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
3171             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
3172                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
3173         }
3174
3175         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
3176             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
3177              (flags & BTRFS_BLOCK_GROUP_RAID10) |
3178              (flags & BTRFS_BLOCK_GROUP_DUP))) {
3179                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
3180         }
3181
3182 out:
3183         /* extended -> chunk profile */
3184         flags &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3185         return flags;
3186 }
3187
3188 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3189 {
3190         if (flags & BTRFS_BLOCK_GROUP_DATA)
3191                 flags |= root->fs_info->avail_data_alloc_bits;
3192         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3193                 flags |= root->fs_info->avail_system_alloc_bits;
3194         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3195                 flags |= root->fs_info->avail_metadata_alloc_bits;
3196
3197         return btrfs_reduce_alloc_profile(root, flags);
3198 }
3199
3200 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3201 {
3202         u64 flags;
3203
3204         if (data)
3205                 flags = BTRFS_BLOCK_GROUP_DATA;
3206         else if (root == root->fs_info->chunk_root)
3207                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3208         else
3209                 flags = BTRFS_BLOCK_GROUP_METADATA;
3210
3211         return get_alloc_profile(root, flags);
3212 }
3213
3214 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
3215 {
3216         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
3217                                                        BTRFS_BLOCK_GROUP_DATA);
3218 }
3219
3220 /*
3221  * This will check the space that the inode allocates from to make sure we have
3222  * enough space for bytes.
3223  */
3224 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3225 {
3226         struct btrfs_space_info *data_sinfo;
3227         struct btrfs_root *root = BTRFS_I(inode)->root;
3228         u64 used;
3229         int ret = 0, committed = 0, alloc_chunk = 1;
3230
3231         /* make sure bytes are sectorsize aligned */
3232         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3233
3234         if (root == root->fs_info->tree_root ||
3235             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3236                 alloc_chunk = 0;
3237                 committed = 1;
3238         }
3239
3240         data_sinfo = BTRFS_I(inode)->space_info;
3241         if (!data_sinfo)
3242                 goto alloc;
3243
3244 again:
3245         /* make sure we have enough space to handle the data first */
3246         spin_lock(&data_sinfo->lock);
3247         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3248                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3249                 data_sinfo->bytes_may_use;
3250
3251         if (used + bytes > data_sinfo->total_bytes) {
3252                 struct btrfs_trans_handle *trans;
3253
3254                 /*
3255                  * if we don't have enough free bytes in this space then we need
3256                  * to alloc a new chunk.
3257                  */
3258                 if (!data_sinfo->full && alloc_chunk) {
3259                         u64 alloc_target;
3260
3261                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3262                         spin_unlock(&data_sinfo->lock);
3263 alloc:
3264                         alloc_target = btrfs_get_alloc_profile(root, 1);
3265                         trans = btrfs_join_transaction(root);
3266                         if (IS_ERR(trans))
3267                                 return PTR_ERR(trans);
3268
3269                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3270                                              bytes + 2 * 1024 * 1024,
3271                                              alloc_target,
3272                                              CHUNK_ALLOC_NO_FORCE);
3273                         btrfs_end_transaction(trans, root);
3274                         if (ret < 0) {
3275                                 if (ret != -ENOSPC)
3276                                         return ret;
3277                                 else
3278                                         goto commit_trans;
3279                         }
3280
3281                         if (!data_sinfo) {
3282                                 btrfs_set_inode_space_info(root, inode);
3283                                 data_sinfo = BTRFS_I(inode)->space_info;
3284                         }
3285                         goto again;
3286                 }
3287
3288                 /*
3289                  * If we have less pinned bytes than we want to allocate then
3290                  * don't bother committing the transaction, it won't help us.
3291                  */
3292                 if (data_sinfo->bytes_pinned < bytes)
3293                         committed = 1;
3294                 spin_unlock(&data_sinfo->lock);
3295
3296                 /* commit the current transaction and try again */
3297 commit_trans:
3298                 if (!committed &&
3299                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3300                         committed = 1;
3301                         trans = btrfs_join_transaction(root);
3302                         if (IS_ERR(trans))
3303                                 return PTR_ERR(trans);
3304                         ret = btrfs_commit_transaction(trans, root);
3305                         if (ret)
3306                                 return ret;
3307                         goto again;
3308                 }
3309
3310                 return -ENOSPC;
3311         }
3312         data_sinfo->bytes_may_use += bytes;
3313         trace_btrfs_space_reservation(root->fs_info, "space_info",
3314                                       (u64)data_sinfo, bytes, 1);
3315         spin_unlock(&data_sinfo->lock);
3316
3317         return 0;
3318 }
3319
3320 /*
3321  * Called if we need to clear a data reservation for this inode.
3322  */
3323 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3324 {
3325         struct btrfs_root *root = BTRFS_I(inode)->root;
3326         struct btrfs_space_info *data_sinfo;
3327
3328         /* make sure bytes are sectorsize aligned */
3329         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3330
3331         data_sinfo = BTRFS_I(inode)->space_info;
3332         spin_lock(&data_sinfo->lock);
3333         data_sinfo->bytes_may_use -= bytes;
3334         trace_btrfs_space_reservation(root->fs_info, "space_info",
3335                                       (u64)data_sinfo, bytes, 0);
3336         spin_unlock(&data_sinfo->lock);
3337 }
3338
3339 static void force_metadata_allocation(struct btrfs_fs_info *info)
3340 {
3341         struct list_head *head = &info->space_info;
3342         struct btrfs_space_info *found;
3343
3344         rcu_read_lock();
3345         list_for_each_entry_rcu(found, head, list) {
3346                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3347                         found->force_alloc = CHUNK_ALLOC_FORCE;
3348         }
3349         rcu_read_unlock();
3350 }
3351
3352 static int should_alloc_chunk(struct btrfs_root *root,
3353                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3354                               int force)
3355 {
3356         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3357         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3358         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3359         u64 thresh;
3360
3361         if (force == CHUNK_ALLOC_FORCE)
3362                 return 1;
3363
3364         /*
3365          * We need to take into account the global rsv because for all intents
3366          * and purposes it's used space.  Don't worry about locking the
3367          * global_rsv, it doesn't change except when the transaction commits.
3368          */
3369         num_allocated += global_rsv->size;
3370
3371         /*
3372          * in limited mode, we want to have some free space up to
3373          * about 1% of the FS size.
3374          */
3375         if (force == CHUNK_ALLOC_LIMITED) {
3376                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3377                 thresh = max_t(u64, 64 * 1024 * 1024,
3378                                div_factor_fine(thresh, 1));
3379
3380                 if (num_bytes - num_allocated < thresh)
3381                         return 1;
3382         }
3383         thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3384
3385         /* 256MB or 2% of the FS */
3386         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 2));
3387
3388         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 8))
3389                 return 0;
3390         return 1;
3391 }
3392
3393 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3394                           struct btrfs_root *extent_root, u64 alloc_bytes,
3395                           u64 flags, int force)
3396 {
3397         struct btrfs_space_info *space_info;
3398         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3399         int wait_for_alloc = 0;
3400         int ret = 0;
3401
3402         BUG_ON(!profile_is_valid(flags, 0));
3403
3404         space_info = __find_space_info(extent_root->fs_info, flags);
3405         if (!space_info) {
3406                 ret = update_space_info(extent_root->fs_info, flags,
3407                                         0, 0, &space_info);
3408                 BUG_ON(ret);
3409         }
3410         BUG_ON(!space_info);
3411
3412 again:
3413         spin_lock(&space_info->lock);
3414         if (space_info->force_alloc)
3415                 force = space_info->force_alloc;
3416         if (space_info->full) {
3417                 spin_unlock(&space_info->lock);
3418                 return 0;
3419         }
3420
3421         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3422                 spin_unlock(&space_info->lock);
3423                 return 0;
3424         } else if (space_info->chunk_alloc) {
3425                 wait_for_alloc = 1;
3426         } else {
3427                 space_info->chunk_alloc = 1;
3428         }
3429
3430         spin_unlock(&space_info->lock);
3431
3432         mutex_lock(&fs_info->chunk_mutex);
3433
3434         /*
3435          * The chunk_mutex is held throughout the entirety of a chunk
3436          * allocation, so once we've acquired the chunk_mutex we know that the
3437          * other guy is done and we need to recheck and see if we should
3438          * allocate.
3439          */
3440         if (wait_for_alloc) {
3441                 mutex_unlock(&fs_info->chunk_mutex);
3442                 wait_for_alloc = 0;
3443                 goto again;
3444         }
3445
3446         /*
3447          * If we have mixed data/metadata chunks we want to make sure we keep
3448          * allocating mixed chunks instead of individual chunks.
3449          */
3450         if (btrfs_mixed_space_info(space_info))
3451                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3452
3453         /*
3454          * if we're doing a data chunk, go ahead and make sure that
3455          * we keep a reasonable number of metadata chunks allocated in the
3456          * FS as well.
3457          */
3458         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3459                 fs_info->data_chunk_allocations++;
3460                 if (!(fs_info->data_chunk_allocations %
3461                       fs_info->metadata_ratio))
3462                         force_metadata_allocation(fs_info);
3463         }
3464
3465         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3466         if (ret < 0 && ret != -ENOSPC)
3467                 goto out;
3468
3469         spin_lock(&space_info->lock);
3470         if (ret)
3471                 space_info->full = 1;
3472         else
3473                 ret = 1;
3474
3475         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3476         space_info->chunk_alloc = 0;
3477         spin_unlock(&space_info->lock);
3478 out:
3479         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3480         return ret;
3481 }
3482
3483 /*
3484  * shrink metadata reservation for delalloc
3485  */
3486 static int shrink_delalloc(struct btrfs_root *root, u64 to_reclaim,
3487                            bool wait_ordered)
3488 {
3489         struct btrfs_block_rsv *block_rsv;
3490         struct btrfs_space_info *space_info;
3491         struct btrfs_trans_handle *trans;
3492         u64 reserved;
3493         u64 max_reclaim;
3494         u64 reclaimed = 0;
3495         long time_left;
3496         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3497         int loops = 0;
3498         unsigned long progress;
3499
3500         trans = (struct btrfs_trans_handle *)current->journal_info;
3501         block_rsv = &root->fs_info->delalloc_block_rsv;
3502         space_info = block_rsv->space_info;
3503
3504         smp_mb();
3505         reserved = space_info->bytes_may_use;
3506         progress = space_info->reservation_progress;
3507
3508         if (reserved == 0)
3509                 return 0;
3510
3511         smp_mb();
3512         if (root->fs_info->delalloc_bytes == 0) {
3513                 if (trans)
3514                         return 0;
3515                 btrfs_wait_ordered_extents(root, 0, 0);
3516                 return 0;
3517         }
3518
3519         max_reclaim = min(reserved, to_reclaim);
3520         nr_pages = max_t(unsigned long, nr_pages,
3521                          max_reclaim >> PAGE_CACHE_SHIFT);
3522         while (loops < 1024) {
3523                 /* have the flusher threads jump in and do some IO */
3524                 smp_mb();
3525                 nr_pages = min_t(unsigned long, nr_pages,
3526                        root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
3527                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages,
3528                                                 WB_REASON_FS_FREE_SPACE);
3529
3530                 spin_lock(&space_info->lock);
3531                 if (reserved > space_info->bytes_may_use)
3532                         reclaimed += reserved - space_info->bytes_may_use;
3533                 reserved = space_info->bytes_may_use;
3534                 spin_unlock(&space_info->lock);
3535
3536                 loops++;
3537
3538                 if (reserved == 0 || reclaimed >= max_reclaim)
3539                         break;
3540
3541                 if (trans && trans->transaction->blocked)
3542                         return -EAGAIN;
3543
3544                 if (wait_ordered && !trans) {
3545                         btrfs_wait_ordered_extents(root, 0, 0);
3546                 } else {
3547                         time_left = schedule_timeout_interruptible(1);
3548
3549                         /* We were interrupted, exit */
3550                         if (time_left)
3551                                 break;
3552                 }
3553
3554                 /* we've kicked the IO a few times, if anything has been freed,
3555                  * exit.  There is no sense in looping here for a long time
3556                  * when we really need to commit the transaction, or there are
3557                  * just too many writers without enough free space
3558                  */
3559
3560                 if (loops > 3) {
3561                         smp_mb();
3562                         if (progress != space_info->reservation_progress)
3563                                 break;
3564                 }
3565
3566         }
3567
3568         return reclaimed >= to_reclaim;
3569 }
3570
3571 /**
3572  * maybe_commit_transaction - possibly commit the transaction if its ok to
3573  * @root - the root we're allocating for
3574  * @bytes - the number of bytes we want to reserve
3575  * @force - force the commit
3576  *
3577  * This will check to make sure that committing the transaction will actually
3578  * get us somewhere and then commit the transaction if it does.  Otherwise it
3579  * will return -ENOSPC.
3580  */
3581 static int may_commit_transaction(struct btrfs_root *root,
3582                                   struct btrfs_space_info *space_info,
3583                                   u64 bytes, int force)
3584 {
3585         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
3586         struct btrfs_trans_handle *trans;
3587
3588         trans = (struct btrfs_trans_handle *)current->journal_info;
3589         if (trans)
3590                 return -EAGAIN;
3591
3592         if (force)
3593                 goto commit;
3594
3595         /* See if there is enough pinned space to make this reservation */
3596         spin_lock(&space_info->lock);
3597         if (space_info->bytes_pinned >= bytes) {
3598                 spin_unlock(&space_info->lock);
3599                 goto commit;
3600         }
3601         spin_unlock(&space_info->lock);
3602
3603         /*
3604          * See if there is some space in the delayed insertion reservation for
3605          * this reservation.
3606          */
3607         if (space_info != delayed_rsv->space_info)
3608                 return -ENOSPC;
3609
3610         spin_lock(&delayed_rsv->lock);
3611         if (delayed_rsv->size < bytes) {
3612                 spin_unlock(&delayed_rsv->lock);
3613                 return -ENOSPC;
3614         }
3615         spin_unlock(&delayed_rsv->lock);
3616
3617 commit:
3618         trans = btrfs_join_transaction(root);
3619         if (IS_ERR(trans))
3620                 return -ENOSPC;
3621
3622         return btrfs_commit_transaction(trans, root);
3623 }
3624
3625 /**
3626  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
3627  * @root - the root we're allocating for
3628  * @block_rsv - the block_rsv we're allocating for
3629  * @orig_bytes - the number of bytes we want
3630  * @flush - wether or not we can flush to make our reservation
3631  *
3632  * This will reserve orgi_bytes number of bytes from the space info associated
3633  * with the block_rsv.  If there is not enough space it will make an attempt to
3634  * flush out space to make room.  It will do this by flushing delalloc if
3635  * possible or committing the transaction.  If flush is 0 then no attempts to
3636  * regain reservations will be made and this will fail if there is not enough
3637  * space already.
3638  */
3639 static int reserve_metadata_bytes(struct btrfs_root *root,
3640                                   struct btrfs_block_rsv *block_rsv,
3641                                   u64 orig_bytes, int flush)
3642 {
3643         struct btrfs_space_info *space_info = block_rsv->space_info;
3644         u64 used;
3645         u64 num_bytes = orig_bytes;
3646         int retries = 0;
3647         int ret = 0;
3648         bool committed = false;
3649         bool flushing = false;
3650         bool wait_ordered = false;
3651
3652 again:
3653         ret = 0;
3654         spin_lock(&space_info->lock);
3655         /*
3656          * We only want to wait if somebody other than us is flushing and we are
3657          * actually alloed to flush.
3658          */
3659         while (flush && !flushing && space_info->flush) {
3660                 spin_unlock(&space_info->lock);
3661                 /*
3662                  * If we have a trans handle we can't wait because the flusher
3663                  * may have to commit the transaction, which would mean we would
3664                  * deadlock since we are waiting for the flusher to finish, but
3665                  * hold the current transaction open.
3666                  */
3667                 if (current->journal_info)
3668                         return -EAGAIN;
3669                 ret = wait_event_interruptible(space_info->wait,
3670                                                !space_info->flush);
3671                 /* Must have been interrupted, return */
3672                 if (ret)
3673                         return -EINTR;
3674
3675                 spin_lock(&space_info->lock);
3676         }
3677
3678         ret = -ENOSPC;
3679         used = space_info->bytes_used + space_info->bytes_reserved +
3680                 space_info->bytes_pinned + space_info->bytes_readonly +
3681                 space_info->bytes_may_use;
3682
3683         /*
3684          * The idea here is that we've not already over-reserved the block group
3685          * then we can go ahead and save our reservation first and then start
3686          * flushing if we need to.  Otherwise if we've already overcommitted
3687          * lets start flushing stuff first and then come back and try to make
3688          * our reservation.
3689          */
3690         if (used <= space_info->total_bytes) {
3691                 if (used + orig_bytes <= space_info->total_bytes) {
3692                         space_info->bytes_may_use += orig_bytes;
3693                         trace_btrfs_space_reservation(root->fs_info,
3694                                                       "space_info",
3695                                                       (u64)space_info,
3696                                                       orig_bytes, 1);
3697                         ret = 0;
3698                 } else {
3699                         /*
3700                          * Ok set num_bytes to orig_bytes since we aren't
3701                          * overocmmitted, this way we only try and reclaim what
3702                          * we need.
3703                          */
3704                         num_bytes = orig_bytes;
3705                 }
3706         } else {
3707                 /*
3708                  * Ok we're over committed, set num_bytes to the overcommitted
3709                  * amount plus the amount of bytes that we need for this
3710                  * reservation.
3711                  */
3712                 wait_ordered = true;
3713                 num_bytes = used - space_info->total_bytes +
3714                         (orig_bytes * (retries + 1));
3715         }
3716
3717         if (ret) {
3718                 u64 profile = btrfs_get_alloc_profile(root, 0);
3719                 u64 avail;
3720
3721                 /*
3722                  * If we have a lot of space that's pinned, don't bother doing
3723                  * the overcommit dance yet and just commit the transaction.
3724                  */
3725                 avail = (space_info->total_bytes - space_info->bytes_used) * 8;
3726                 do_div(avail, 10);
3727                 if (space_info->bytes_pinned >= avail && flush && !committed) {
3728                         space_info->flush = 1;
3729                         flushing = true;
3730                         spin_unlock(&space_info->lock);
3731                         ret = may_commit_transaction(root, space_info,
3732                                                      orig_bytes, 1);
3733                         if (ret)
3734                                 goto out;
3735                         committed = true;
3736                         goto again;
3737                 }
3738
3739                 spin_lock(&root->fs_info->free_chunk_lock);
3740                 avail = root->fs_info->free_chunk_space;
3741
3742                 /*
3743                  * If we have dup, raid1 or raid10 then only half of the free
3744                  * space is actually useable.
3745                  */
3746                 if (profile & (BTRFS_BLOCK_GROUP_DUP |
3747                                BTRFS_BLOCK_GROUP_RAID1 |
3748                                BTRFS_BLOCK_GROUP_RAID10))
3749                         avail >>= 1;
3750
3751                 /*
3752                  * If we aren't flushing don't let us overcommit too much, say
3753                  * 1/8th of the space.  If we can flush, let it overcommit up to
3754                  * 1/2 of the space.
3755                  */
3756                 if (flush)
3757                         avail >>= 3;
3758                 else
3759                         avail >>= 1;
3760                  spin_unlock(&root->fs_info->free_chunk_lock);
3761
3762                 if (used + num_bytes < space_info->total_bytes + avail) {
3763                         space_info->bytes_may_use += orig_bytes;
3764                         trace_btrfs_space_reservation(root->fs_info,
3765                                                       "space_info",
3766                                                       (u64)space_info,
3767                                                       orig_bytes, 1);
3768                         ret = 0;
3769                 } else {
3770                         wait_ordered = true;
3771                 }
3772         }
3773
3774         /*
3775          * Couldn't make our reservation, save our place so while we're trying
3776          * to reclaim space we can actually use it instead of somebody else
3777          * stealing it from us.
3778          */
3779         if (ret && flush) {
3780                 flushing = true;
3781                 space_info->flush = 1;
3782         }
3783
3784         spin_unlock(&space_info->lock);
3785
3786         if (!ret || !flush)
3787                 goto out;
3788
3789         /*
3790          * We do synchronous shrinking since we don't actually unreserve
3791          * metadata until after the IO is completed.
3792          */
3793         ret = shrink_delalloc(root, num_bytes, wait_ordered);
3794         if (ret < 0)
3795                 goto out;
3796
3797         ret = 0;
3798
3799         /*
3800          * So if we were overcommitted it's possible that somebody else flushed
3801          * out enough space and we simply didn't have enough space to reclaim,
3802          * so go back around and try again.
3803          */
3804         if (retries < 2) {
3805                 wait_ordered = true;
3806                 retries++;
3807                 goto again;
3808         }
3809
3810         ret = -ENOSPC;
3811         if (committed)
3812                 goto out;
3813
3814         ret = may_commit_transaction(root, space_info, orig_bytes, 0);
3815         if (!ret) {
3816                 committed = true;
3817                 goto again;
3818         }
3819
3820 out:
3821         if (flushing) {
3822                 spin_lock(&space_info->lock);
3823                 space_info->flush = 0;
3824                 wake_up_all(&space_info->wait);
3825                 spin_unlock(&space_info->lock);
3826         }
3827         return ret;
3828 }
3829
3830 static struct btrfs_block_rsv *get_block_rsv(struct btrfs_trans_handle *trans,
3831                                              struct btrfs_root *root)
3832 {
3833         struct btrfs_block_rsv *block_rsv = NULL;
3834
3835         if (root->ref_cows || root == root->fs_info->csum_root)
3836                 block_rsv = trans->block_rsv;
3837
3838         if (!block_rsv)
3839                 block_rsv = root->block_rsv;
3840
3841         if (!block_rsv)
3842                 block_rsv = &root->fs_info->empty_block_rsv;
3843
3844         return block_rsv;
3845 }
3846
3847 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
3848                                u64 num_bytes)
3849 {
3850         int ret = -ENOSPC;
3851         spin_lock(&block_rsv->lock);
3852         if (block_rsv->reserved >= num_bytes) {
3853                 block_rsv->reserved -= num_bytes;
3854                 if (block_rsv->reserved < block_rsv->size)
3855                         block_rsv->full = 0;
3856                 ret = 0;
3857         }
3858         spin_unlock(&block_rsv->lock);
3859         return ret;
3860 }
3861
3862 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
3863                                 u64 num_bytes, int update_size)
3864 {
3865         spin_lock(&block_rsv->lock);
3866         block_rsv->reserved += num_bytes;
3867         if (update_size)
3868                 block_rsv->size += num_bytes;
3869         else if (block_rsv->reserved >= block_rsv->size)
3870                 block_rsv->full = 1;
3871         spin_unlock(&block_rsv->lock);
3872 }
3873
3874 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
3875                                     struct btrfs_block_rsv *block_rsv,
3876                                     struct btrfs_block_rsv *dest, u64 num_bytes)
3877 {
3878         struct btrfs_space_info *space_info = block_rsv->space_info;
3879
3880         spin_lock(&block_rsv->lock);
3881         if (num_bytes == (u64)-1)
3882                 num_bytes = block_rsv->size;
3883         block_rsv->size -= num_bytes;
3884         if (block_rsv->reserved >= block_rsv->size) {
3885                 num_bytes = block_rsv->reserved - block_rsv->size;
3886                 block_rsv->reserved = block_rsv->size;
3887                 block_rsv->full = 1;
3888         } else {
3889                 num_bytes = 0;
3890         }
3891         spin_unlock(&block_rsv->lock);
3892
3893         if (num_bytes > 0) {
3894                 if (dest) {
3895                         spin_lock(&dest->lock);
3896                         if (!dest->full) {
3897                                 u64 bytes_to_add;
3898
3899                                 bytes_to_add = dest->size - dest->reserved;
3900                                 bytes_to_add = min(num_bytes, bytes_to_add);
3901                                 dest->reserved += bytes_to_add;
3902                                 if (dest->reserved >= dest->size)
3903                                         dest->full = 1;
3904                                 num_bytes -= bytes_to_add;
3905                         }
3906                         spin_unlock(&dest->lock);
3907                 }
3908                 if (num_bytes) {
3909                         spin_lock(&space_info->lock);
3910                         space_info->bytes_may_use -= num_bytes;
3911                         trace_btrfs_space_reservation(fs_info, "space_info",
3912                                                       (u64)space_info,
3913                                                       num_bytes, 0);
3914                         space_info->reservation_progress++;
3915                         spin_unlock(&space_info->lock);
3916                 }
3917         }
3918 }
3919
3920 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
3921                                    struct btrfs_block_rsv *dst, u64 num_bytes)
3922 {
3923         int ret;
3924
3925         ret = block_rsv_use_bytes(src, num_bytes);
3926         if (ret)
3927                 return ret;
3928
3929         block_rsv_add_bytes(dst, num_bytes, 1);
3930         return 0;
3931 }
3932
3933 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
3934 {
3935         memset(rsv, 0, sizeof(*rsv));
3936         spin_lock_init(&rsv->lock);
3937 }
3938
3939 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
3940 {
3941         struct btrfs_block_rsv *block_rsv;
3942         struct btrfs_fs_info *fs_info = root->fs_info;
3943
3944         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
3945         if (!block_rsv)
3946                 return NULL;
3947
3948         btrfs_init_block_rsv(block_rsv);
3949         block_rsv->space_info = __find_space_info(fs_info,
3950                                                   BTRFS_BLOCK_GROUP_METADATA);
3951         return block_rsv;
3952 }
3953
3954 void btrfs_free_block_rsv(struct btrfs_root *root,
3955                           struct btrfs_block_rsv *rsv)
3956 {
3957         btrfs_block_rsv_release(root, rsv, (u64)-1);
3958         kfree(rsv);
3959 }
3960
3961 static inline int __block_rsv_add(struct btrfs_root *root,
3962                                   struct btrfs_block_rsv *block_rsv,
3963                                   u64 num_bytes, int flush)
3964 {
3965         int ret;
3966
3967         if (num_bytes == 0)
3968                 return 0;
3969
3970         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
3971         if (!ret) {
3972                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
3973                 return 0;
3974         }
3975
3976         return ret;
3977 }
3978
3979 int btrfs_block_rsv_add(struct btrfs_root *root,
3980                         struct btrfs_block_rsv *block_rsv,
3981                         u64 num_bytes)
3982 {
3983         return __block_rsv_add(root, block_rsv, num_bytes, 1);
3984 }
3985
3986 int btrfs_block_rsv_add_noflush(struct btrfs_root *root,
3987                                 struct btrfs_block_rsv *block_rsv,
3988                                 u64 num_bytes)
3989 {
3990         return __block_rsv_add(root, block_rsv, num_bytes, 0);
3991 }
3992
3993 int btrfs_block_rsv_check(struct btrfs_root *root,
3994                           struct btrfs_block_rsv *block_rsv, int min_factor)
3995 {
3996         u64 num_bytes = 0;
3997         int ret = -ENOSPC;
3998
3999         if (!block_rsv)
4000                 return 0;
4001
4002         spin_lock(&block_rsv->lock);
4003         num_bytes = div_factor(block_rsv->size, min_factor);
4004         if (block_rsv->reserved >= num_bytes)
4005                 ret = 0;
4006         spin_unlock(&block_rsv->lock);
4007
4008         return ret;
4009 }
4010
4011 static inline int __btrfs_block_rsv_refill(struct btrfs_root *root,
4012                                            struct btrfs_block_rsv *block_rsv,
4013                                            u64 min_reserved, int flush)
4014 {
4015         u64 num_bytes = 0;
4016         int ret = -ENOSPC;
4017
4018         if (!block_rsv)
4019                 return 0;
4020
4021         spin_lock(&block_rsv->lock);
4022         num_bytes = min_reserved;
4023         if (block_rsv->reserved >= num_bytes)
4024                 ret = 0;
4025         else
4026                 num_bytes -= block_rsv->reserved;
4027         spin_unlock(&block_rsv->lock);
4028
4029         if (!ret)
4030                 return 0;
4031
4032         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4033         if (!ret) {
4034                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4035                 return 0;
4036         }
4037
4038         return ret;
4039 }
4040
4041 int btrfs_block_rsv_refill(struct btrfs_root *root,
4042                            struct btrfs_block_rsv *block_rsv,
4043                            u64 min_reserved)
4044 {
4045         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 1);
4046 }
4047
4048 int btrfs_block_rsv_refill_noflush(struct btrfs_root *root,
4049                                    struct btrfs_block_rsv *block_rsv,
4050                                    u64 min_reserved)
4051 {
4052         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 0);
4053 }
4054
4055 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4056                             struct btrfs_block_rsv *dst_rsv,
4057                             u64 num_bytes)
4058 {
4059         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4060 }
4061
4062 void btrfs_block_rsv_release(struct btrfs_root *root,
4063                              struct btrfs_block_rsv *block_rsv,
4064                              u64 num_bytes)
4065 {
4066         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4067         if (global_rsv->full || global_rsv == block_rsv ||
4068             block_rsv->space_info != global_rsv->space_info)
4069                 global_rsv = NULL;
4070         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4071                                 num_bytes);
4072 }
4073
4074 /*
4075  * helper to calculate size of global block reservation.
4076  * the desired value is sum of space used by extent tree,
4077  * checksum tree and root tree
4078  */
4079 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4080 {
4081         struct btrfs_space_info *sinfo;
4082         u64 num_bytes;
4083         u64 meta_used;
4084         u64 data_used;
4085         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4086
4087         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4088         spin_lock(&sinfo->lock);
4089         data_used = sinfo->bytes_used;
4090         spin_unlock(&sinfo->lock);
4091
4092         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4093         spin_lock(&sinfo->lock);
4094         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4095                 data_used = 0;
4096         meta_used = sinfo->bytes_used;
4097         spin_unlock(&sinfo->lock);
4098
4099         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4100                     csum_size * 2;
4101         num_bytes += div64_u64(data_used + meta_used, 50);
4102
4103         if (num_bytes * 3 > meta_used)
4104                 num_bytes = div64_u64(meta_used, 3);
4105
4106         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4107 }
4108
4109 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4110 {
4111         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4112         struct btrfs_space_info *sinfo = block_rsv->space_info;
4113         u64 num_bytes;
4114
4115         num_bytes = calc_global_metadata_size(fs_info);
4116
4117         spin_lock(&block_rsv->lock);
4118         spin_lock(&sinfo->lock);
4119
4120         block_rsv->size = num_bytes;
4121
4122         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4123                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4124                     sinfo->bytes_may_use;
4125
4126         if (sinfo->total_bytes > num_bytes) {
4127                 num_bytes = sinfo->total_bytes - num_bytes;
4128                 block_rsv->reserved += num_bytes;
4129                 sinfo->bytes_may_use += num_bytes;
4130                 trace_btrfs_space_reservation(fs_info, "space_info",
4131                                               (u64)sinfo, num_bytes, 1);
4132         }
4133
4134         if (block_rsv->reserved >= block_rsv->size) {
4135                 num_bytes = block_rsv->reserved - block_rsv->size;
4136                 sinfo->bytes_may_use -= num_bytes;
4137                 trace_btrfs_space_reservation(fs_info, "space_info",
4138                                               (u64)sinfo, num_bytes, 0);
4139                 sinfo->reservation_progress++;
4140                 block_rsv->reserved = block_rsv->size;
4141                 block_rsv->full = 1;
4142         }
4143
4144         spin_unlock(&sinfo->lock);
4145         spin_unlock(&block_rsv->lock);
4146 }
4147
4148 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4149 {
4150         struct btrfs_space_info *space_info;
4151
4152         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4153         fs_info->chunk_block_rsv.space_info = space_info;
4154
4155         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4156         fs_info->global_block_rsv.space_info = space_info;
4157         fs_info->delalloc_block_rsv.space_info = space_info;
4158         fs_info->trans_block_rsv.space_info = space_info;
4159         fs_info->empty_block_rsv.space_info = space_info;
4160         fs_info->delayed_block_rsv.space_info = space_info;
4161
4162         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4163         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4164         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4165         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4166         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4167
4168         update_global_block_rsv(fs_info);
4169 }
4170
4171 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4172 {
4173         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4174                                 (u64)-1);
4175         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4176         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4177         WARN_ON(fs_info->trans_block_rsv.size > 0);
4178         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4179         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4180         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4181         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4182         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4183 }
4184
4185 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4186                                   struct btrfs_root *root)
4187 {
4188         if (!trans->bytes_reserved)
4189                 return;
4190
4191         trace_btrfs_space_reservation(root->fs_info, "transaction", (u64)trans,
4192                                       trans->bytes_reserved, 0);
4193         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4194         trans->bytes_reserved = 0;
4195 }
4196
4197 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4198                                   struct inode *inode)
4199 {
4200         struct btrfs_root *root = BTRFS_I(inode)->root;
4201         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4202         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4203
4204         /*
4205          * We need to hold space in order to delete our orphan item once we've
4206          * added it, so this takes the reservation so we can release it later
4207          * when we are truly done with the orphan item.
4208          */
4209         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4210         trace_btrfs_space_reservation(root->fs_info, "orphan",
4211                                       btrfs_ino(inode), num_bytes, 1);
4212         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4213 }
4214
4215 void btrfs_orphan_release_metadata(struct inode *inode)
4216 {
4217         struct btrfs_root *root = BTRFS_I(inode)->root;
4218         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4219         trace_btrfs_space_reservation(root->fs_info, "orphan",
4220                                       btrfs_ino(inode), num_bytes, 0);
4221         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4222 }
4223
4224 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
4225                                 struct btrfs_pending_snapshot *pending)
4226 {
4227         struct btrfs_root *root = pending->root;
4228         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4229         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
4230         /*
4231          * two for root back/forward refs, two for directory entries
4232          * and one for root of the snapshot.
4233          */
4234         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
4235         dst_rsv->space_info = src_rsv->space_info;
4236         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4237 }
4238
4239 /**
4240  * drop_outstanding_extent - drop an outstanding extent
4241  * @inode: the inode we're dropping the extent for
4242  *
4243  * This is called when we are freeing up an outstanding extent, either called
4244  * after an error or after an extent is written.  This will return the number of
4245  * reserved extents that need to be freed.  This must be called with
4246  * BTRFS_I(inode)->lock held.
4247  */
4248 static unsigned drop_outstanding_extent(struct inode *inode)
4249 {
4250         unsigned drop_inode_space = 0;
4251         unsigned dropped_extents = 0;
4252
4253         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4254         BTRFS_I(inode)->outstanding_extents--;
4255
4256         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4257             BTRFS_I(inode)->delalloc_meta_reserved) {
4258                 drop_inode_space = 1;
4259                 BTRFS_I(inode)->delalloc_meta_reserved = 0;
4260         }
4261
4262         /*
4263          * If we have more or the same amount of outsanding extents than we have
4264          * reserved then we need to leave the reserved extents count alone.
4265          */
4266         if (BTRFS_I(inode)->outstanding_extents >=
4267             BTRFS_I(inode)->reserved_extents)
4268                 return drop_inode_space;
4269
4270         dropped_extents = BTRFS_I(inode)->reserved_extents -
4271                 BTRFS_I(inode)->outstanding_extents;
4272         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4273         return dropped_extents + drop_inode_space;
4274 }
4275
4276 /**
4277  * calc_csum_metadata_size - return the amount of metada space that must be
4278  *      reserved/free'd for the given bytes.
4279  * @inode: the inode we're manipulating
4280  * @num_bytes: the number of bytes in question
4281  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4282  *
4283  * This adjusts the number of csum_bytes in the inode and then returns the
4284  * correct amount of metadata that must either be reserved or freed.  We
4285  * calculate how many checksums we can fit into one leaf and then divide the
4286  * number of bytes that will need to be checksumed by this value to figure out
4287  * how many checksums will be required.  If we are adding bytes then the number
4288  * may go up and we will return the number of additional bytes that must be
4289  * reserved.  If it is going down we will return the number of bytes that must
4290  * be freed.
4291  *
4292  * This must be called with BTRFS_I(inode)->lock held.
4293  */
4294 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4295                                    int reserve)
4296 {
4297         struct btrfs_root *root = BTRFS_I(inode)->root;
4298         u64 csum_size;
4299         int num_csums_per_leaf;
4300         int num_csums;
4301         int old_csums;
4302
4303         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4304             BTRFS_I(inode)->csum_bytes == 0)
4305                 return 0;
4306
4307         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4308         if (reserve)
4309                 BTRFS_I(inode)->csum_bytes += num_bytes;
4310         else
4311                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4312         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4313         num_csums_per_leaf = (int)div64_u64(csum_size,
4314                                             sizeof(struct btrfs_csum_item) +
4315                                             sizeof(struct btrfs_disk_key));
4316         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4317         num_csums = num_csums + num_csums_per_leaf - 1;
4318         num_csums = num_csums / num_csums_per_leaf;
4319
4320         old_csums = old_csums + num_csums_per_leaf - 1;
4321         old_csums = old_csums / num_csums_per_leaf;
4322
4323         /* No change, no need to reserve more */
4324         if (old_csums == num_csums)
4325                 return 0;
4326
4327         if (reserve)
4328                 return btrfs_calc_trans_metadata_size(root,
4329                                                       num_csums - old_csums);
4330
4331         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4332 }
4333
4334 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4335 {
4336         struct btrfs_root *root = BTRFS_I(inode)->root;
4337         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4338         u64 to_reserve = 0;
4339         u64 csum_bytes;
4340         unsigned nr_extents = 0;
4341         int extra_reserve = 0;
4342         int flush = 1;
4343         int ret;
4344
4345         /* Need to be holding the i_mutex here if we aren't free space cache */
4346         if (btrfs_is_free_space_inode(root, inode))
4347                 flush = 0;
4348
4349         if (flush && btrfs_transaction_in_commit(root->fs_info))
4350                 schedule_timeout(1);
4351
4352         mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4353         num_bytes = ALIGN(num_bytes, root->sectorsize);
4354
4355         spin_lock(&BTRFS_I(inode)->lock);
4356         BTRFS_I(inode)->outstanding_extents++;
4357
4358         if (BTRFS_I(inode)->outstanding_extents >
4359             BTRFS_I(inode)->reserved_extents)
4360                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4361                         BTRFS_I(inode)->reserved_extents;
4362
4363         /*
4364          * Add an item to reserve for updating the inode when we complete the
4365          * delalloc io.
4366          */
4367         if (!BTRFS_I(inode)->delalloc_meta_reserved) {
4368                 nr_extents++;
4369                 extra_reserve = 1;
4370         }
4371
4372         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4373         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4374         csum_bytes = BTRFS_I(inode)->csum_bytes;
4375         spin_unlock(&BTRFS_I(inode)->lock);
4376
4377         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4378         if (ret) {
4379                 u64 to_free = 0;
4380                 unsigned dropped;
4381
4382                 spin_lock(&BTRFS_I(inode)->lock);
4383                 dropped = drop_outstanding_extent(inode);
4384                 /*
4385                  * If the inodes csum_bytes is the same as the original
4386                  * csum_bytes then we know we haven't raced with any free()ers
4387                  * so we can just reduce our inodes csum bytes and carry on.
4388                  * Otherwise we have to do the normal free thing to account for
4389                  * the case that the free side didn't free up its reserve
4390                  * because of this outstanding reservation.
4391                  */
4392                 if (BTRFS_I(inode)->csum_bytes == csum_bytes)
4393                         calc_csum_metadata_size(inode, num_bytes, 0);
4394                 else
4395                         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4396                 spin_unlock(&BTRFS_I(inode)->lock);
4397                 if (dropped)
4398                         to_free += btrfs_calc_trans_metadata_size(root, dropped);
4399
4400                 if (to_free) {
4401                         btrfs_block_rsv_release(root, block_rsv, to_free);
4402                         trace_btrfs_space_reservation(root->fs_info,
4403                                                       "delalloc",
4404                                                       btrfs_ino(inode),
4405                                                       to_free, 0);
4406                 }
4407                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4408                 return ret;
4409         }
4410
4411         spin_lock(&BTRFS_I(inode)->lock);
4412         if (extra_reserve) {
4413                 BTRFS_I(inode)->delalloc_meta_reserved = 1;
4414                 nr_extents--;
4415         }
4416         BTRFS_I(inode)->reserved_extents += nr_extents;
4417         spin_unlock(&BTRFS_I(inode)->lock);
4418         mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
4419
4420         if (to_reserve)
4421                 trace_btrfs_space_reservation(root->fs_info,"delalloc",
4422                                               btrfs_ino(inode), to_reserve, 1);
4423         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4424
4425         return 0;
4426 }
4427
4428 /**
4429  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
4430  * @inode: the inode to release the reservation for
4431  * @num_bytes: the number of bytes we're releasing
4432  *
4433  * This will release the metadata reservation for an inode.  This can be called
4434  * once we complete IO for a given set of bytes to release their metadata
4435  * reservations.
4436  */
4437 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4438 {
4439         struct btrfs_root *root = BTRFS_I(inode)->root;
4440         u64 to_free = 0;
4441         unsigned dropped;
4442
4443         num_bytes = ALIGN(num_bytes, root->sectorsize);
4444         spin_lock(&BTRFS_I(inode)->lock);
4445         dropped = drop_outstanding_extent(inode);
4446
4447         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4448         spin_unlock(&BTRFS_I(inode)->lock);
4449         if (dropped > 0)
4450                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4451
4452         trace_btrfs_space_reservation(root->fs_info, "delalloc",
4453                                       btrfs_ino(inode), to_free, 0);
4454         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4455                                 to_free);
4456 }
4457
4458 /**
4459  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
4460  * @inode: inode we're writing to
4461  * @num_bytes: the number of bytes we want to allocate
4462  *
4463  * This will do the following things
4464  *
4465  * o reserve space in the data space info for num_bytes
4466  * o reserve space in the metadata space info based on number of outstanding
4467  *   extents and how much csums will be needed
4468  * o add to the inodes ->delalloc_bytes
4469  * o add it to the fs_info's delalloc inodes list.
4470  *
4471  * This will return 0 for success and -ENOSPC if there is no space left.
4472  */
4473 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4474 {
4475         int ret;
4476
4477         ret = btrfs_check_data_free_space(inode, num_bytes);
4478         if (ret)
4479                 return ret;
4480
4481         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4482         if (ret) {
4483                 btrfs_free_reserved_data_space(inode, num_bytes);
4484                 return ret;
4485         }
4486
4487         return 0;
4488 }
4489
4490 /**
4491  * btrfs_delalloc_release_space - release data and metadata space for delalloc
4492  * @inode: inode we're releasing space for
4493  * @num_bytes: the number of bytes we want to free up
4494  *
4495  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
4496  * called in the case that we don't need the metadata AND data reservations
4497  * anymore.  So if there is an error or we insert an inline extent.
4498  *
4499  * This function will release the metadata space that was not used and will
4500  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
4501  * list if there are no delalloc bytes left.
4502  */
4503 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4504 {
4505         btrfs_delalloc_release_metadata(inode, num_bytes);
4506         btrfs_free_reserved_data_space(inode, num_bytes);
4507 }
4508
4509 static int update_block_group(struct btrfs_trans_handle *trans,
4510                               struct btrfs_root *root,
4511                               u64 bytenr, u64 num_bytes, int alloc)
4512 {
4513         struct btrfs_block_group_cache *cache = NULL;
4514         struct btrfs_fs_info *info = root->fs_info;
4515         u64 total = num_bytes;
4516         u64 old_val;
4517         u64 byte_in_group;
4518         int factor;
4519
4520         /* block accounting for super block */
4521         spin_lock(&info->delalloc_lock);
4522         old_val = btrfs_super_bytes_used(info->super_copy);
4523         if (alloc)
4524                 old_val += num_bytes;
4525         else
4526                 old_val -= num_bytes;
4527         btrfs_set_super_bytes_used(info->super_copy, old_val);
4528         spin_unlock(&info->delalloc_lock);
4529
4530         while (total) {
4531                 cache = btrfs_lookup_block_group(info, bytenr);
4532                 if (!cache)
4533                         return -1;
4534                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4535                                     BTRFS_BLOCK_GROUP_RAID1 |
4536                                     BTRFS_BLOCK_GROUP_RAID10))
4537                         factor = 2;
4538                 else
4539                         factor = 1;
4540                 /*
4541                  * If this block group has free space cache written out, we
4542                  * need to make sure to load it if we are removing space.  This
4543                  * is because we need the unpinning stage to actually add the
4544                  * space back to the block group, otherwise we will leak space.
4545                  */
4546                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4547                         cache_block_group(cache, trans, NULL, 1);
4548
4549                 byte_in_group = bytenr - cache->key.objectid;
4550                 WARN_ON(byte_in_group > cache->key.offset);
4551
4552                 spin_lock(&cache->space_info->lock);
4553                 spin_lock(&cache->lock);
4554
4555                 if (btrfs_test_opt(root, SPACE_CACHE) &&
4556                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4557                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4558
4559                 cache->dirty = 1;
4560                 old_val = btrfs_block_group_used(&cache->item);
4561                 num_bytes = min(total, cache->key.offset - byte_in_group);
4562                 if (alloc) {
4563                         old_val += num_bytes;
4564                         btrfs_set_block_group_used(&cache->item, old_val);
4565                         cache->reserved -= num_bytes;
4566                         cache->space_info->bytes_reserved -= num_bytes;
4567                         cache->space_info->bytes_used += num_bytes;
4568                         cache->space_info->disk_used += num_bytes * factor;
4569                         spin_unlock(&cache->lock);
4570                         spin_unlock(&cache->space_info->lock);
4571                 } else {
4572                         old_val -= num_bytes;
4573                         btrfs_set_block_group_used(&cache->item, old_val);
4574                         cache->pinned += num_bytes;
4575                         cache->space_info->bytes_pinned += num_bytes;
4576                         cache->space_info->bytes_used -= num_bytes;
4577                         cache->space_info->disk_used -= num_bytes * factor;
4578                         spin_unlock(&cache->lock);
4579                         spin_unlock(&cache->space_info->lock);
4580
4581                         set_extent_dirty(info->pinned_extents,
4582                                          bytenr, bytenr + num_bytes - 1,
4583                                          GFP_NOFS | __GFP_NOFAIL);
4584                 }
4585                 btrfs_put_block_group(cache);
4586                 total -= num_bytes;
4587                 bytenr += num_bytes;
4588         }
4589         return 0;
4590 }
4591
4592 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4593 {
4594         struct btrfs_block_group_cache *cache;
4595         u64 bytenr;
4596
4597         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4598         if (!cache)
4599                 return 0;
4600
4601         bytenr = cache->key.objectid;
4602         btrfs_put_block_group(cache);
4603
4604         return bytenr;
4605 }
4606
4607 static int pin_down_extent(struct btrfs_root *root,
4608                            struct btrfs_block_group_cache *cache,
4609                            u64 bytenr, u64 num_bytes, int reserved)
4610 {
4611         spin_lock(&cache->space_info->lock);
4612         spin_lock(&cache->lock);
4613         cache->pinned += num_bytes;
4614         cache->space_info->bytes_pinned += num_bytes;
4615         if (reserved) {
4616                 cache->reserved -= num_bytes;
4617                 cache->space_info->bytes_reserved -= num_bytes;
4618         }
4619         spin_unlock(&cache->lock);
4620         spin_unlock(&cache->space_info->lock);
4621
4622         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4623                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4624         return 0;
4625 }
4626
4627 /*
4628  * this function must be called within transaction
4629  */
4630 int btrfs_pin_extent(struct btrfs_root *root,
4631                      u64 bytenr, u64 num_bytes, int reserved)
4632 {
4633         struct btrfs_block_group_cache *cache;
4634
4635         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4636         BUG_ON(!cache);
4637
4638         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4639
4640         btrfs_put_block_group(cache);
4641         return 0;
4642 }
4643
4644 /*
4645  * this function must be called within transaction
4646  */
4647 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
4648                                     struct btrfs_root *root,
4649                                     u64 bytenr, u64 num_bytes)
4650 {
4651         struct btrfs_block_group_cache *cache;
4652
4653         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4654         BUG_ON(!cache);
4655
4656         /*
4657          * pull in the free space cache (if any) so that our pin
4658          * removes the free space from the cache.  We have load_only set
4659          * to one because the slow code to read in the free extents does check
4660          * the pinned extents.
4661          */
4662         cache_block_group(cache, trans, root, 1);
4663
4664         pin_down_extent(root, cache, bytenr, num_bytes, 0);
4665
4666         /* remove us from the free space cache (if we're there at all) */
4667         btrfs_remove_free_space(cache, bytenr, num_bytes);
4668         btrfs_put_block_group(cache);
4669         return 0;
4670 }
4671
4672 /**
4673  * btrfs_update_reserved_bytes - update the block_group and space info counters
4674  * @cache:      The cache we are manipulating
4675  * @num_bytes:  The number of bytes in question
4676  * @reserve:    One of the reservation enums
4677  *
4678  * This is called by the allocator when it reserves space, or by somebody who is
4679  * freeing space that was never actually used on disk.  For example if you
4680  * reserve some space for a new leaf in transaction A and before transaction A
4681  * commits you free that leaf, you call this with reserve set to 0 in order to
4682  * clear the reservation.
4683  *
4684  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
4685  * ENOSPC accounting.  For data we handle the reservation through clearing the
4686  * delalloc bits in the io_tree.  We have to do this since we could end up
4687  * allocating less disk space for the amount of data we have reserved in the
4688  * case of compression.
4689  *
4690  * If this is a reservation and the block group has become read only we cannot
4691  * make the reservation and return -EAGAIN, otherwise this function always
4692  * succeeds.
4693  */
4694 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4695                                        u64 num_bytes, int reserve)
4696 {
4697         struct btrfs_space_info *space_info = cache->space_info;
4698         int ret = 0;
4699         spin_lock(&space_info->lock);
4700         spin_lock(&cache->lock);
4701         if (reserve != RESERVE_FREE) {
4702                 if (cache->ro) {
4703                         ret = -EAGAIN;
4704                 } else {
4705                         cache->reserved += num_bytes;
4706                         space_info->bytes_reserved += num_bytes;
4707                         if (reserve == RESERVE_ALLOC) {
4708                                 trace_btrfs_space_reservation(cache->fs_info,
4709                                                               "space_info",
4710                                                               (u64)space_info,
4711                                                               num_bytes, 0);
4712                                 space_info->bytes_may_use -= num_bytes;
4713                         }
4714                 }
4715         } else {
4716                 if (cache->ro)
4717                         space_info->bytes_readonly += num_bytes;
4718                 cache->reserved -= num_bytes;
4719                 space_info->bytes_reserved -= num_bytes;
4720                 space_info->reservation_progress++;
4721         }
4722         spin_unlock(&cache->lock);
4723         spin_unlock(&space_info->lock);
4724         return ret;
4725 }
4726
4727 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4728                                 struct btrfs_root *root)
4729 {
4730         struct btrfs_fs_info *fs_info = root->fs_info;
4731         struct btrfs_caching_control *next;
4732         struct btrfs_caching_control *caching_ctl;
4733         struct btrfs_block_group_cache *cache;
4734
4735         down_write(&fs_info->extent_commit_sem);
4736
4737         list_for_each_entry_safe(caching_ctl, next,
4738                                  &fs_info->caching_block_groups, list) {
4739                 cache = caching_ctl->block_group;
4740                 if (block_group_cache_done(cache)) {
4741                         cache->last_byte_to_unpin = (u64)-1;
4742                         list_del_init(&caching_ctl->list);
4743                         put_caching_control(caching_ctl);
4744                 } else {
4745                         cache->last_byte_to_unpin = caching_ctl->progress;
4746                 }
4747         }
4748
4749         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4750                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4751         else
4752                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4753
4754         up_write(&fs_info->extent_commit_sem);
4755
4756         update_global_block_rsv(fs_info);
4757         return 0;
4758 }
4759
4760 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4761 {
4762         struct btrfs_fs_info *fs_info = root->fs_info;
4763         struct btrfs_block_group_cache *cache = NULL;
4764         u64 len;
4765
4766         while (start <= end) {
4767                 if (!cache ||
4768                     start >= cache->key.objectid + cache->key.offset) {
4769                         if (cache)
4770                                 btrfs_put_block_group(cache);
4771                         cache = btrfs_lookup_block_group(fs_info, start);
4772                         BUG_ON(!cache);
4773                 }
4774
4775                 len = cache->key.objectid + cache->key.offset - start;
4776                 len = min(len, end + 1 - start);
4777
4778                 if (start < cache->last_byte_to_unpin) {
4779                         len = min(len, cache->last_byte_to_unpin - start);
4780                         btrfs_add_free_space(cache, start, len);
4781                 }
4782
4783                 start += len;
4784
4785                 spin_lock(&cache->space_info->lock);
4786                 spin_lock(&cache->lock);
4787                 cache->pinned -= len;
4788                 cache->space_info->bytes_pinned -= len;
4789                 if (cache->ro)
4790                         cache->space_info->bytes_readonly += len;
4791                 spin_unlock(&cache->lock);
4792                 spin_unlock(&cache->space_info->lock);
4793         }
4794
4795         if (cache)
4796                 btrfs_put_block_group(cache);
4797         return 0;
4798 }
4799
4800 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4801                                struct btrfs_root *root)
4802 {
4803         struct btrfs_fs_info *fs_info = root->fs_info;
4804         struct extent_io_tree *unpin;
4805         u64 start;
4806         u64 end;
4807         int ret;
4808
4809         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4810                 unpin = &fs_info->freed_extents[1];
4811         else
4812                 unpin = &fs_info->freed_extents[0];
4813
4814         while (1) {
4815                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4816                                             EXTENT_DIRTY);
4817                 if (ret)
4818                         break;
4819
4820                 if (btrfs_test_opt(root, DISCARD))
4821                         ret = btrfs_discard_extent(root, start,
4822                                                    end + 1 - start, NULL);
4823
4824                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4825                 unpin_extent_range(root, start, end);
4826                 cond_resched();
4827         }
4828
4829         return 0;
4830 }
4831
4832 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
4833                                 struct btrfs_root *root,
4834                                 u64 bytenr, u64 num_bytes, u64 parent,
4835                                 u64 root_objectid, u64 owner_objectid,
4836                                 u64 owner_offset, int refs_to_drop,
4837                                 struct btrfs_delayed_extent_op *extent_op)
4838 {
4839         struct btrfs_key key;
4840         struct btrfs_path *path;
4841         struct btrfs_fs_info *info = root->fs_info;
4842         struct btrfs_root *extent_root = info->extent_root;
4843         struct extent_buffer *leaf;
4844         struct btrfs_extent_item *ei;
4845         struct btrfs_extent_inline_ref *iref;
4846         int ret;
4847         int is_data;
4848         int extent_slot = 0;
4849         int found_extent = 0;
4850         int num_to_del = 1;
4851         u32 item_size;
4852         u64 refs;
4853
4854         path = btrfs_alloc_path();
4855         if (!path)
4856                 return -ENOMEM;
4857
4858         path->reada = 1;
4859         path->leave_spinning = 1;
4860
4861         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
4862         BUG_ON(!is_data && refs_to_drop != 1);
4863
4864         ret = lookup_extent_backref(trans, extent_root, path, &iref,
4865                                     bytenr, num_bytes, parent,
4866                                     root_objectid, owner_objectid,
4867                                     owner_offset);
4868         if (ret == 0) {
4869                 extent_slot = path->slots[0];
4870                 while (extent_slot >= 0) {
4871                         btrfs_item_key_to_cpu(path->nodes[0], &key,
4872                                               extent_slot);
4873                         if (key.objectid != bytenr)
4874                                 break;
4875                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
4876                             key.offset == num_bytes) {
4877                                 found_extent = 1;
4878                                 break;
4879                         }
4880                         if (path->slots[0] - extent_slot > 5)
4881                                 break;
4882                         extent_slot--;
4883                 }
4884 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4885                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
4886                 if (found_extent && item_size < sizeof(*ei))
4887                         found_extent = 0;
4888 #endif
4889                 if (!found_extent) {
4890                         BUG_ON(iref);
4891                         ret = remove_extent_backref(trans, extent_root, path,
4892                                                     NULL, refs_to_drop,
4893                                                     is_data);
4894                         BUG_ON(ret);
4895                         btrfs_release_path(path);
4896                         path->leave_spinning = 1;
4897
4898                         key.objectid = bytenr;
4899                         key.type = BTRFS_EXTENT_ITEM_KEY;
4900                         key.offset = num_bytes;
4901
4902                         ret = btrfs_search_slot(trans, extent_root,
4903                                                 &key, path, -1, 1);
4904                         if (ret) {
4905                                 printk(KERN_ERR "umm, got %d back from search"
4906                                        ", was looking for %llu\n", ret,
4907                                        (unsigned long long)bytenr);
4908                                 if (ret > 0)
4909                                         btrfs_print_leaf(extent_root,
4910                                                          path->nodes[0]);
4911                         }
4912                         BUG_ON(ret);
4913                         extent_slot = path->slots[0];
4914                 }
4915         } else {
4916                 btrfs_print_leaf(extent_root, path->nodes[0]);
4917                 WARN_ON(1);
4918                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
4919                        "parent %llu root %llu  owner %llu offset %llu\n",
4920                        (unsigned long long)bytenr,
4921                        (unsigned long long)parent,
4922                        (unsigned long long)root_objectid,
4923                        (unsigned long long)owner_objectid,
4924                        (unsigned long long)owner_offset);
4925         }
4926
4927         leaf = path->nodes[0];
4928         item_size = btrfs_item_size_nr(leaf, extent_slot);
4929 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4930         if (item_size < sizeof(*ei)) {
4931                 BUG_ON(found_extent || extent_slot != path->slots[0]);
4932                 ret = convert_extent_item_v0(trans, extent_root, path,
4933                                              owner_objectid, 0);
4934                 BUG_ON(ret < 0);
4935
4936                 btrfs_release_path(path);
4937                 path->leave_spinning = 1;
4938
4939                 key.objectid = bytenr;
4940                 key.type = BTRFS_EXTENT_ITEM_KEY;
4941                 key.offset = num_bytes;
4942
4943                 ret = btrfs_search_slot(trans, extent_root, &key, path,
4944                                         -1, 1);
4945                 if (ret) {
4946                         printk(KERN_ERR "umm, got %d back from search"
4947                                ", was looking for %llu\n", ret,
4948                                (unsigned long long)bytenr);
4949                         btrfs_print_leaf(extent_root, path->nodes[0]);
4950                 }
4951                 BUG_ON(ret);
4952                 extent_slot = path->slots[0];
4953                 leaf = path->nodes[0];
4954                 item_size = btrfs_item_size_nr(leaf, extent_slot);
4955         }
4956 #endif
4957         BUG_ON(item_size < sizeof(*ei));
4958         ei = btrfs_item_ptr(leaf, extent_slot,
4959                             struct btrfs_extent_item);
4960         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4961                 struct btrfs_tree_block_info *bi;
4962                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
4963                 bi = (struct btrfs_tree_block_info *)(ei + 1);
4964                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
4965         }
4966
4967         refs = btrfs_extent_refs(leaf, ei);
4968         BUG_ON(refs < refs_to_drop);
4969         refs -= refs_to_drop;
4970
4971         if (refs > 0) {
4972                 if (extent_op)
4973                         __run_delayed_extent_op(extent_op, leaf, ei);
4974                 /*
4975                  * In the case of inline back ref, reference count will
4976                  * be updated by remove_extent_backref
4977                  */
4978                 if (iref) {
4979                         BUG_ON(!found_extent);
4980                 } else {
4981                         btrfs_set_extent_refs(leaf, ei, refs);
4982                         btrfs_mark_buffer_dirty(leaf);
4983                 }
4984                 if (found_extent) {
4985                         ret = remove_extent_backref(trans, extent_root, path,
4986                                                     iref, refs_to_drop,
4987                                                     is_data);
4988                         BUG_ON(ret);
4989                 }
4990         } else {
4991                 if (found_extent) {
4992                         BUG_ON(is_data && refs_to_drop !=
4993                                extent_data_ref_count(root, path, iref));
4994                         if (iref) {
4995                                 BUG_ON(path->slots[0] != extent_slot);
4996                         } else {
4997                                 BUG_ON(path->slots[0] != extent_slot + 1);
4998                                 path->slots[0] = extent_slot;
4999                                 num_to_del = 2;
5000                         }
5001                 }
5002
5003                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5004                                       num_to_del);
5005                 BUG_ON(ret);
5006                 btrfs_release_path(path);
5007
5008                 if (is_data) {
5009                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5010                         BUG_ON(ret);
5011                 } else {
5012                         invalidate_mapping_pages(info->btree_inode->i_mapping,
5013                              bytenr >> PAGE_CACHE_SHIFT,
5014                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
5015                 }
5016
5017                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
5018                 BUG_ON(ret);
5019         }
5020         btrfs_free_path(path);
5021         return ret;
5022 }
5023
5024 /*
5025  * when we free an block, it is possible (and likely) that we free the last
5026  * delayed ref for that extent as well.  This searches the delayed ref tree for
5027  * a given extent, and if there are no other delayed refs to be processed, it
5028  * removes it from the tree.
5029  */
5030 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5031                                       struct btrfs_root *root, u64 bytenr)
5032 {
5033         struct btrfs_delayed_ref_head *head;
5034         struct btrfs_delayed_ref_root *delayed_refs;
5035         struct btrfs_delayed_ref_node *ref;
5036         struct rb_node *node;
5037         int ret = 0;
5038
5039         delayed_refs = &trans->transaction->delayed_refs;
5040         spin_lock(&delayed_refs->lock);
5041         head = btrfs_find_delayed_ref_head(trans, bytenr);
5042         if (!head)
5043                 goto out;
5044
5045         node = rb_prev(&head->node.rb_node);
5046         if (!node)
5047                 goto out;
5048
5049         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5050
5051         /* there are still entries for this ref, we can't drop it */
5052         if (ref->bytenr == bytenr)
5053                 goto out;
5054
5055         if (head->extent_op) {
5056                 if (!head->must_insert_reserved)
5057                         goto out;
5058                 kfree(head->extent_op);
5059                 head->extent_op = NULL;
5060         }
5061
5062         /*
5063          * waiting for the lock here would deadlock.  If someone else has it
5064          * locked they are already in the process of dropping it anyway
5065          */
5066         if (!mutex_trylock(&head->mutex))
5067                 goto out;
5068
5069         /*
5070          * at this point we have a head with no other entries.  Go
5071          * ahead and process it.
5072          */
5073         head->node.in_tree = 0;
5074         rb_erase(&head->node.rb_node, &delayed_refs->root);
5075
5076         delayed_refs->num_entries--;
5077         if (waitqueue_active(&delayed_refs->seq_wait))
5078                 wake_up(&delayed_refs->seq_wait);
5079
5080         /*
5081          * we don't take a ref on the node because we're removing it from the
5082          * tree, so we just steal the ref the tree was holding.
5083          */
5084         delayed_refs->num_heads--;
5085         if (list_empty(&head->cluster))
5086                 delayed_refs->num_heads_ready--;
5087
5088         list_del_init(&head->cluster);
5089         spin_unlock(&delayed_refs->lock);
5090
5091         BUG_ON(head->extent_op);
5092         if (head->must_insert_reserved)
5093                 ret = 1;
5094
5095         mutex_unlock(&head->mutex);
5096         btrfs_put_delayed_ref(&head->node);
5097         return ret;
5098 out:
5099         spin_unlock(&delayed_refs->lock);
5100         return 0;
5101 }
5102
5103 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5104                            struct btrfs_root *root,
5105                            struct extent_buffer *buf,
5106                            u64 parent, int last_ref, int for_cow)
5107 {
5108         struct btrfs_block_group_cache *cache = NULL;
5109         int ret;
5110
5111         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5112                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5113                                         buf->start, buf->len,
5114                                         parent, root->root_key.objectid,
5115                                         btrfs_header_level(buf),
5116                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5117                 BUG_ON(ret);
5118         }
5119
5120         if (!last_ref)
5121                 return;
5122
5123         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5124
5125         if (btrfs_header_generation(buf) == trans->transid) {
5126                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5127                         ret = check_ref_cleanup(trans, root, buf->start);
5128                         if (!ret)
5129                                 goto out;
5130                 }
5131
5132                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5133                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5134                         goto out;
5135                 }
5136
5137                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5138
5139                 btrfs_add_free_space(cache, buf->start, buf->len);
5140                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5141         }
5142 out:
5143         /*
5144          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5145          * anymore.
5146          */
5147         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5148         btrfs_put_block_group(cache);
5149 }
5150
5151 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
5152                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
5153                       u64 owner, u64 offset, int for_cow)
5154 {
5155         int ret;
5156         struct btrfs_fs_info *fs_info = root->fs_info;
5157
5158         /*
5159          * tree log blocks never actually go into the extent allocation
5160          * tree, just update pinning info and exit early.
5161          */
5162         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5163                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5164                 /* unlocks the pinned mutex */
5165                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5166                 ret = 0;
5167         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5168                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
5169                                         num_bytes,
5170                                         parent, root_objectid, (int)owner,
5171                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
5172                 BUG_ON(ret);
5173         } else {
5174                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
5175                                                 num_bytes,
5176                                                 parent, root_objectid, owner,
5177                                                 offset, BTRFS_DROP_DELAYED_REF,
5178                                                 NULL, for_cow);
5179                 BUG_ON(ret);
5180         }
5181         return ret;
5182 }
5183
5184 static u64 stripe_align(struct btrfs_root *root, u64 val)
5185 {
5186         u64 mask = ((u64)root->stripesize - 1);
5187         u64 ret = (val + mask) & ~mask;
5188         return ret;
5189 }
5190
5191 /*
5192  * when we wait for progress in the block group caching, its because
5193  * our allocation attempt failed at least once.  So, we must sleep
5194  * and let some progress happen before we try again.
5195  *
5196  * This function will sleep at least once waiting for new free space to
5197  * show up, and then it will check the block group free space numbers
5198  * for our min num_bytes.  Another option is to have it go ahead
5199  * and look in the rbtree for a free extent of a given size, but this
5200  * is a good start.
5201  */
5202 static noinline int
5203 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
5204                                 u64 num_bytes)
5205 {
5206         struct btrfs_caching_control *caching_ctl;
5207         DEFINE_WAIT(wait);
5208
5209         caching_ctl = get_caching_control(cache);
5210         if (!caching_ctl)
5211                 return 0;
5212
5213         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
5214                    (cache->free_space_ctl->free_space >= num_bytes));
5215
5216         put_caching_control(caching_ctl);
5217         return 0;
5218 }
5219
5220 static noinline int
5221 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
5222 {
5223         struct btrfs_caching_control *caching_ctl;
5224         DEFINE_WAIT(wait);
5225
5226         caching_ctl = get_caching_control(cache);
5227         if (!caching_ctl)
5228                 return 0;
5229
5230         wait_event(caching_ctl->wait, block_group_cache_done(cache));
5231
5232         put_caching_control(caching_ctl);
5233         return 0;
5234 }
5235
5236 static int get_block_group_index(struct btrfs_block_group_cache *cache)
5237 {
5238         int index;
5239         if (cache->flags & BTRFS_BLOCK_GROUP_RAID10)
5240                 index = 0;
5241         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID1)
5242                 index = 1;
5243         else if (cache->flags & BTRFS_BLOCK_GROUP_DUP)
5244                 index = 2;
5245         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID0)
5246                 index = 3;
5247         else
5248                 index = 4;
5249         return index;
5250 }
5251
5252 enum btrfs_loop_type {
5253         LOOP_FIND_IDEAL = 0,
5254         LOOP_CACHING_NOWAIT = 1,
5255         LOOP_CACHING_WAIT = 2,
5256         LOOP_ALLOC_CHUNK = 3,
5257         LOOP_NO_EMPTY_SIZE = 4,
5258 };
5259
5260 /*
5261  * walks the btree of allocated extents and find a hole of a given size.
5262  * The key ins is changed to record the hole:
5263  * ins->objectid == block start
5264  * ins->flags = BTRFS_EXTENT_ITEM_KEY
5265  * ins->offset == number of blocks
5266  * Any available blocks before search_start are skipped.
5267  */
5268 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
5269                                      struct btrfs_root *orig_root,
5270                                      u64 num_bytes, u64 empty_size,
5271                                      u64 search_start, u64 search_end,
5272                                      u64 hint_byte, struct btrfs_key *ins,
5273                                      u64 data)
5274 {
5275         int ret = 0;
5276         struct btrfs_root *root = orig_root->fs_info->extent_root;
5277         struct btrfs_free_cluster *last_ptr = NULL;
5278         struct btrfs_block_group_cache *block_group = NULL;
5279         struct btrfs_block_group_cache *used_block_group;
5280         int empty_cluster = 2 * 1024 * 1024;
5281         int allowed_chunk_alloc = 0;
5282         int done_chunk_alloc = 0;
5283         struct btrfs_space_info *space_info;
5284         int loop = 0;
5285         int index = 0;
5286         int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ?
5287                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
5288         bool found_uncached_bg = false;
5289         bool failed_cluster_refill = false;
5290         bool failed_alloc = false;
5291         bool use_cluster = true;
5292         bool have_caching_bg = false;
5293         u64 ideal_cache_percent = 0;
5294         u64 ideal_cache_offset = 0;
5295
5296         WARN_ON(num_bytes < root->sectorsize);
5297         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
5298         ins->objectid = 0;
5299         ins->offset = 0;
5300
5301         trace_find_free_extent(orig_root, num_bytes, empty_size, data);
5302
5303         space_info = __find_space_info(root->fs_info, data);
5304         if (!space_info) {
5305                 printk(KERN_ERR "No space info for %llu\n", data);
5306                 return -ENOSPC;
5307         }
5308
5309         /*
5310          * If the space info is for both data and metadata it means we have a
5311          * small filesystem and we can't use the clustering stuff.
5312          */
5313         if (btrfs_mixed_space_info(space_info))
5314                 use_cluster = false;
5315
5316         if (orig_root->ref_cows || empty_size)
5317                 allowed_chunk_alloc = 1;
5318
5319         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
5320                 last_ptr = &root->fs_info->meta_alloc_cluster;
5321                 if (!btrfs_test_opt(root, SSD))
5322                         empty_cluster = 64 * 1024;
5323         }
5324
5325         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
5326             btrfs_test_opt(root, SSD)) {
5327                 last_ptr = &root->fs_info->data_alloc_cluster;
5328         }
5329
5330         if (last_ptr) {
5331                 spin_lock(&last_ptr->lock);
5332                 if (last_ptr->block_group)
5333                         hint_byte = last_ptr->window_start;
5334                 spin_unlock(&last_ptr->lock);
5335         }
5336
5337         search_start = max(search_start, first_logical_byte(root, 0));
5338         search_start = max(search_start, hint_byte);
5339
5340         if (!last_ptr)
5341                 empty_cluster = 0;
5342
5343         if (search_start == hint_byte) {
5344 ideal_cache:
5345                 block_group = btrfs_lookup_block_group(root->fs_info,
5346                                                        search_start);
5347                 used_block_group = block_group;
5348                 /*
5349                  * we don't want to use the block group if it doesn't match our
5350                  * allocation bits, or if its not cached.
5351                  *
5352                  * However if we are re-searching with an ideal block group
5353                  * picked out then we don't care that the block group is cached.
5354                  */
5355                 if (block_group && block_group_bits(block_group, data) &&
5356                     (block_group->cached != BTRFS_CACHE_NO ||
5357                      search_start == ideal_cache_offset)) {
5358                         down_read(&space_info->groups_sem);
5359                         if (list_empty(&block_group->list) ||
5360                             block_group->ro) {
5361                                 /*
5362                                  * someone is removing this block group,
5363                                  * we can't jump into the have_block_group
5364                                  * target because our list pointers are not
5365                                  * valid
5366                                  */
5367                                 btrfs_put_block_group(block_group);
5368                                 up_read(&space_info->groups_sem);
5369                         } else {
5370                                 index = get_block_group_index(block_group);
5371                                 goto have_block_group;
5372                         }
5373                 } else if (block_group) {
5374                         btrfs_put_block_group(block_group);
5375                 }
5376         }
5377 search:
5378         have_caching_bg = false;
5379         down_read(&space_info->groups_sem);
5380         list_for_each_entry(block_group, &space_info->block_groups[index],
5381                             list) {
5382                 u64 offset;
5383                 int cached;
5384
5385                 used_block_group = block_group;
5386                 btrfs_get_block_group(block_group);
5387                 search_start = block_group->key.objectid;
5388
5389                 /*
5390                  * this can happen if we end up cycling through all the
5391                  * raid types, but we want to make sure we only allocate
5392                  * for the proper type.
5393                  */
5394                 if (!block_group_bits(block_group, data)) {
5395                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
5396                                 BTRFS_BLOCK_GROUP_RAID1 |
5397                                 BTRFS_BLOCK_GROUP_RAID10;
5398
5399                         /*
5400                          * if they asked for extra copies and this block group
5401                          * doesn't provide them, bail.  This does allow us to
5402                          * fill raid0 from raid1.
5403                          */
5404                         if ((data & extra) && !(block_group->flags & extra))
5405                                 goto loop;
5406                 }
5407
5408 have_block_group:
5409                 cached = block_group_cache_done(block_group);
5410                 if (unlikely(!cached)) {
5411                         u64 free_percent;
5412
5413                         found_uncached_bg = true;
5414                         ret = cache_block_group(block_group, trans,
5415                                                 orig_root, 1);
5416                         if (block_group->cached == BTRFS_CACHE_FINISHED)
5417                                 goto alloc;
5418
5419                         free_percent = btrfs_block_group_used(&block_group->item);
5420                         free_percent *= 100;
5421                         free_percent = div64_u64(free_percent,
5422                                                  block_group->key.offset);
5423                         free_percent = 100 - free_percent;
5424                         if (free_percent > ideal_cache_percent &&
5425                             likely(!block_group->ro)) {
5426                                 ideal_cache_offset = block_group->key.objectid;
5427                                 ideal_cache_percent = free_percent;
5428                         }
5429
5430                         /*
5431                          * The caching workers are limited to 2 threads, so we
5432                          * can queue as much work as we care to.
5433                          */
5434                         if (loop > LOOP_FIND_IDEAL) {
5435                                 ret = cache_block_group(block_group, trans,
5436                                                         orig_root, 0);
5437                                 BUG_ON(ret);
5438                         }
5439
5440                         /*
5441                          * If loop is set for cached only, try the next block
5442                          * group.
5443                          */
5444                         if (loop == LOOP_FIND_IDEAL)
5445                                 goto loop;
5446                 }
5447
5448 alloc:
5449                 if (unlikely(block_group->ro))
5450                         goto loop;
5451
5452                 /*
5453                  * Ok we want to try and use the cluster allocator, so
5454                  * lets look there
5455                  */
5456                 if (last_ptr) {
5457                         /*
5458                          * the refill lock keeps out other
5459                          * people trying to start a new cluster
5460                          */
5461                         spin_lock(&last_ptr->refill_lock);
5462                         used_block_group = last_ptr->block_group;
5463                         if (used_block_group != block_group &&
5464                             (!used_block_group ||
5465                              used_block_group->ro ||
5466                              !block_group_bits(used_block_group, data))) {
5467                                 used_block_group = block_group;
5468                                 goto refill_cluster;
5469                         }
5470
5471                         if (used_block_group != block_group)
5472                                 btrfs_get_block_group(used_block_group);
5473
5474                         offset = btrfs_alloc_from_cluster(used_block_group,
5475                           last_ptr, num_bytes, used_block_group->key.objectid);
5476                         if (offset) {
5477                                 /* we have a block, we're done */
5478                                 spin_unlock(&last_ptr->refill_lock);
5479                                 trace_btrfs_reserve_extent_cluster(root,
5480                                         block_group, search_start, num_bytes);
5481                                 goto checks;
5482                         }
5483
5484                         WARN_ON(last_ptr->block_group != used_block_group);
5485                         if (used_block_group != block_group) {
5486                                 btrfs_put_block_group(used_block_group);
5487                                 used_block_group = block_group;
5488                         }
5489 refill_cluster:
5490                         BUG_ON(used_block_group != block_group);
5491                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
5492                          * set up a new clusters, so lets just skip it
5493                          * and let the allocator find whatever block
5494                          * it can find.  If we reach this point, we
5495                          * will have tried the cluster allocator
5496                          * plenty of times and not have found
5497                          * anything, so we are likely way too
5498                          * fragmented for the clustering stuff to find
5499                          * anything.
5500                          *
5501                          * However, if the cluster is taken from the
5502                          * current block group, release the cluster
5503                          * first, so that we stand a better chance of
5504                          * succeeding in the unclustered
5505                          * allocation.  */
5506                         if (loop >= LOOP_NO_EMPTY_SIZE &&
5507                             last_ptr->block_group != block_group) {
5508                                 spin_unlock(&last_ptr->refill_lock);
5509                                 goto unclustered_alloc;
5510                         }
5511
5512                         /*
5513                          * this cluster didn't work out, free it and
5514                          * start over
5515                          */
5516                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5517
5518                         if (loop >= LOOP_NO_EMPTY_SIZE) {
5519                                 spin_unlock(&last_ptr->refill_lock);
5520                                 goto unclustered_alloc;
5521                         }
5522
5523                         /* allocate a cluster in this block group */
5524                         ret = btrfs_find_space_cluster(trans, root,
5525                                                block_group, last_ptr,
5526                                                search_start, num_bytes,
5527                                                empty_cluster + empty_size);
5528                         if (ret == 0) {
5529                                 /*
5530                                  * now pull our allocation out of this
5531                                  * cluster
5532                                  */
5533                                 offset = btrfs_alloc_from_cluster(block_group,
5534                                                   last_ptr, num_bytes,
5535                                                   search_start);
5536                                 if (offset) {
5537                                         /* we found one, proceed */
5538                                         spin_unlock(&last_ptr->refill_lock);
5539                                         trace_btrfs_reserve_extent_cluster(root,
5540                                                 block_group, search_start,
5541                                                 num_bytes);
5542                                         goto checks;
5543                                 }
5544                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5545                                    && !failed_cluster_refill) {
5546                                 spin_unlock(&last_ptr->refill_lock);
5547
5548                                 failed_cluster_refill = true;
5549                                 wait_block_group_cache_progress(block_group,
5550                                        num_bytes + empty_cluster + empty_size);
5551                                 goto have_block_group;
5552                         }
5553
5554                         /*
5555                          * at this point we either didn't find a cluster
5556                          * or we weren't able to allocate a block from our
5557                          * cluster.  Free the cluster we've been trying
5558                          * to use, and go to the next block group
5559                          */
5560                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5561                         spin_unlock(&last_ptr->refill_lock);
5562                         goto loop;
5563                 }
5564
5565 unclustered_alloc:
5566                 spin_lock(&block_group->free_space_ctl->tree_lock);
5567                 if (cached &&
5568                     block_group->free_space_ctl->free_space <
5569                     num_bytes + empty_cluster + empty_size) {
5570                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5571                         goto loop;
5572                 }
5573                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5574
5575                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5576                                                     num_bytes, empty_size);
5577                 /*
5578                  * If we didn't find a chunk, and we haven't failed on this
5579                  * block group before, and this block group is in the middle of
5580                  * caching and we are ok with waiting, then go ahead and wait
5581                  * for progress to be made, and set failed_alloc to true.
5582                  *
5583                  * If failed_alloc is true then we've already waited on this
5584                  * block group once and should move on to the next block group.
5585                  */
5586                 if (!offset && !failed_alloc && !cached &&
5587                     loop > LOOP_CACHING_NOWAIT) {
5588                         wait_block_group_cache_progress(block_group,
5589                                                 num_bytes + empty_size);
5590                         failed_alloc = true;
5591                         goto have_block_group;
5592                 } else if (!offset) {
5593                         if (!cached)
5594                                 have_caching_bg = true;
5595                         goto loop;
5596                 }
5597 checks:
5598                 search_start = stripe_align(root, offset);
5599                 /* move on to the next group */
5600                 if (search_start + num_bytes >= search_end) {
5601                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5602                         goto loop;
5603                 }
5604
5605                 /* move on to the next group */
5606                 if (search_start + num_bytes >
5607                     used_block_group->key.objectid + used_block_group->key.offset) {
5608                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5609                         goto loop;
5610                 }
5611
5612                 if (offset < search_start)
5613                         btrfs_add_free_space(used_block_group, offset,
5614                                              search_start - offset);
5615                 BUG_ON(offset > search_start);
5616
5617                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
5618                                                   alloc_type);
5619                 if (ret == -EAGAIN) {
5620                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5621                         goto loop;
5622                 }
5623
5624                 /* we are all good, lets return */
5625                 ins->objectid = search_start;
5626                 ins->offset = num_bytes;
5627
5628                 trace_btrfs_reserve_extent(orig_root, block_group,
5629                                            search_start, num_bytes);
5630                 if (offset < search_start)
5631                         btrfs_add_free_space(used_block_group, offset,
5632                                              search_start - offset);
5633                 BUG_ON(offset > search_start);
5634                 if (used_block_group != block_group)
5635                         btrfs_put_block_group(used_block_group);
5636                 btrfs_put_block_group(block_group);
5637                 break;
5638 loop:
5639                 failed_cluster_refill = false;
5640                 failed_alloc = false;
5641                 BUG_ON(index != get_block_group_index(block_group));
5642                 if (used_block_group != block_group)
5643                         btrfs_put_block_group(used_block_group);
5644                 btrfs_put_block_group(block_group);
5645         }
5646         up_read(&space_info->groups_sem);
5647
5648         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
5649                 goto search;
5650
5651         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5652                 goto search;
5653
5654         /* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
5655          *                      for them to make caching progress.  Also
5656          *                      determine the best possible bg to cache
5657          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5658          *                      caching kthreads as we move along
5659          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5660          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5661          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5662          *                      again
5663          */
5664         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5665                 index = 0;
5666                 if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
5667                         found_uncached_bg = false;
5668                         loop++;
5669                         if (!ideal_cache_percent)
5670                                 goto search;
5671
5672                         /*
5673                          * 1 of the following 2 things have happened so far
5674                          *
5675                          * 1) We found an ideal block group for caching that
5676                          * is mostly full and will cache quickly, so we might
5677                          * as well wait for it.
5678                          *
5679                          * 2) We searched for cached only and we didn't find
5680                          * anything, and we didn't start any caching kthreads
5681                          * either, so chances are we will loop through and
5682                          * start a couple caching kthreads, and then come back
5683                          * around and just wait for them.  This will be slower
5684                          * because we will have 2 caching kthreads reading at
5685                          * the same time when we could have just started one
5686                          * and waited for it to get far enough to give us an
5687                          * allocation, so go ahead and go to the wait caching
5688                          * loop.
5689                          */
5690                         loop = LOOP_CACHING_WAIT;
5691                         search_start = ideal_cache_offset;
5692                         ideal_cache_percent = 0;
5693                         goto ideal_cache;
5694                 } else if (loop == LOOP_FIND_IDEAL) {
5695                         /*
5696                          * Didn't find a uncached bg, wait on anything we find
5697                          * next.
5698                          */
5699                         loop = LOOP_CACHING_WAIT;
5700                         goto search;
5701                 }
5702
5703                 loop++;
5704
5705                 if (loop == LOOP_ALLOC_CHUNK) {
5706                        if (allowed_chunk_alloc) {
5707                                 ret = do_chunk_alloc(trans, root, num_bytes +
5708                                                      2 * 1024 * 1024, data,
5709                                                      CHUNK_ALLOC_LIMITED);
5710                                 allowed_chunk_alloc = 0;
5711                                 if (ret == 1)
5712                                         done_chunk_alloc = 1;
5713                         } else if (!done_chunk_alloc &&
5714                                    space_info->force_alloc ==
5715                                    CHUNK_ALLOC_NO_FORCE) {
5716                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5717                         }
5718
5719                        /*
5720                         * We didn't allocate a chunk, go ahead and drop the
5721                         * empty size and loop again.
5722                         */
5723                        if (!done_chunk_alloc)
5724                                loop = LOOP_NO_EMPTY_SIZE;
5725                 }
5726
5727                 if (loop == LOOP_NO_EMPTY_SIZE) {
5728                         empty_size = 0;
5729                         empty_cluster = 0;
5730                 }
5731
5732                 goto search;
5733         } else if (!ins->objectid) {
5734                 ret = -ENOSPC;
5735         } else if (ins->objectid) {
5736                 ret = 0;
5737         }
5738
5739         return ret;
5740 }
5741
5742 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5743                             int dump_block_groups)
5744 {
5745         struct btrfs_block_group_cache *cache;
5746         int index = 0;
5747
5748         spin_lock(&info->lock);
5749         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
5750                (unsigned long long)info->flags,
5751                (unsigned long long)(info->total_bytes - info->bytes_used -
5752                                     info->bytes_pinned - info->bytes_reserved -
5753                                     info->bytes_readonly),
5754                (info->full) ? "" : "not ");
5755         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5756                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5757                (unsigned long long)info->total_bytes,
5758                (unsigned long long)info->bytes_used,
5759                (unsigned long long)info->bytes_pinned,
5760                (unsigned long long)info->bytes_reserved,
5761                (unsigned long long)info->bytes_may_use,
5762                (unsigned long long)info->bytes_readonly);
5763         spin_unlock(&info->lock);
5764
5765         if (!dump_block_groups)
5766                 return;
5767
5768         down_read(&info->groups_sem);
5769 again:
5770         list_for_each_entry(cache, &info->block_groups[index], list) {
5771                 spin_lock(&cache->lock);
5772                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
5773                        "%llu pinned %llu reserved\n",
5774                        (unsigned long long)cache->key.objectid,
5775                        (unsigned long long)cache->key.offset,
5776                        (unsigned long long)btrfs_block_group_used(&cache->item),
5777                        (unsigned long long)cache->pinned,
5778                        (unsigned long long)cache->reserved);
5779                 btrfs_dump_free_space(cache, bytes);
5780                 spin_unlock(&cache->lock);
5781         }
5782         if (++index < BTRFS_NR_RAID_TYPES)
5783                 goto again;
5784         up_read(&info->groups_sem);
5785 }
5786
5787 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5788                          struct btrfs_root *root,
5789                          u64 num_bytes, u64 min_alloc_size,
5790                          u64 empty_size, u64 hint_byte,
5791                          u64 search_end, struct btrfs_key *ins,
5792                          u64 data)
5793 {
5794         int ret;
5795         u64 search_start = 0;
5796
5797         data = btrfs_get_alloc_profile(root, data);
5798 again:
5799         /*
5800          * the only place that sets empty_size is btrfs_realloc_node, which
5801          * is not called recursively on allocations
5802          */
5803         if (empty_size || root->ref_cows)
5804                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5805                                      num_bytes + 2 * 1024 * 1024, data,
5806                                      CHUNK_ALLOC_NO_FORCE);
5807
5808         WARN_ON(num_bytes < root->sectorsize);
5809         ret = find_free_extent(trans, root, num_bytes, empty_size,
5810                                search_start, search_end, hint_byte,
5811                                ins, data);
5812
5813         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
5814                 num_bytes = num_bytes >> 1;
5815                 num_bytes = num_bytes & ~(root->sectorsize - 1);
5816                 num_bytes = max(num_bytes, min_alloc_size);
5817                 do_chunk_alloc(trans, root->fs_info->extent_root,
5818                                num_bytes, data, CHUNK_ALLOC_FORCE);
5819                 goto again;
5820         }
5821         if (ret == -ENOSPC && btrfs_test_opt(root, ENOSPC_DEBUG)) {
5822                 struct btrfs_space_info *sinfo;
5823
5824                 sinfo = __find_space_info(root->fs_info, data);
5825                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
5826                        "wanted %llu\n", (unsigned long long)data,
5827                        (unsigned long long)num_bytes);
5828                 dump_space_info(sinfo, num_bytes, 1);
5829         }
5830
5831         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5832
5833         return ret;
5834 }
5835
5836 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
5837                                         u64 start, u64 len, int pin)
5838 {
5839         struct btrfs_block_group_cache *cache;
5840         int ret = 0;
5841
5842         cache = btrfs_lookup_block_group(root->fs_info, start);
5843         if (!cache) {
5844                 printk(KERN_ERR "Unable to find block group for %llu\n",
5845                        (unsigned long long)start);
5846                 return -ENOSPC;
5847         }
5848
5849         if (btrfs_test_opt(root, DISCARD))
5850                 ret = btrfs_discard_extent(root, start, len, NULL);
5851
5852         if (pin)
5853                 pin_down_extent(root, cache, start, len, 1);
5854         else {
5855                 btrfs_add_free_space(cache, start, len);
5856                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
5857         }
5858         btrfs_put_block_group(cache);
5859
5860         trace_btrfs_reserved_extent_free(root, start, len);
5861
5862         return ret;
5863 }
5864
5865 int btrfs_free_reserved_extent(struct btrfs_root *root,
5866                                         u64 start, u64 len)
5867 {
5868         return __btrfs_free_reserved_extent(root, start, len, 0);
5869 }
5870
5871 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
5872                                        u64 start, u64 len)
5873 {
5874         return __btrfs_free_reserved_extent(root, start, len, 1);
5875 }
5876
5877 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5878                                       struct btrfs_root *root,
5879                                       u64 parent, u64 root_objectid,
5880                                       u64 flags, u64 owner, u64 offset,
5881                                       struct btrfs_key *ins, int ref_mod)
5882 {
5883         int ret;
5884         struct btrfs_fs_info *fs_info = root->fs_info;
5885         struct btrfs_extent_item *extent_item;
5886         struct btrfs_extent_inline_ref *iref;
5887         struct btrfs_path *path;
5888         struct extent_buffer *leaf;
5889         int type;
5890         u32 size;
5891
5892         if (parent > 0)
5893                 type = BTRFS_SHARED_DATA_REF_KEY;
5894         else
5895                 type = BTRFS_EXTENT_DATA_REF_KEY;
5896
5897         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
5898
5899         path = btrfs_alloc_path();
5900         if (!path)
5901                 return -ENOMEM;
5902
5903         path->leave_spinning = 1;
5904         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5905                                       ins, size);
5906         BUG_ON(ret);
5907
5908         leaf = path->nodes[0];
5909         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5910                                      struct btrfs_extent_item);
5911         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
5912         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5913         btrfs_set_extent_flags(leaf, extent_item,
5914                                flags | BTRFS_EXTENT_FLAG_DATA);
5915
5916         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
5917         btrfs_set_extent_inline_ref_type(leaf, iref, type);
5918         if (parent > 0) {
5919                 struct btrfs_shared_data_ref *ref;
5920                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
5921                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5922                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
5923         } else {
5924                 struct btrfs_extent_data_ref *ref;
5925                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
5926                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
5927                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
5928                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
5929                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
5930         }
5931
5932         btrfs_mark_buffer_dirty(path->nodes[0]);
5933         btrfs_free_path(path);
5934
5935         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5936         if (ret) {
5937                 printk(KERN_ERR "btrfs update block group failed for %llu "
5938                        "%llu\n", (unsigned long long)ins->objectid,
5939                        (unsigned long long)ins->offset);
5940                 BUG();
5941         }
5942         return ret;
5943 }
5944
5945 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
5946                                      struct btrfs_root *root,
5947                                      u64 parent, u64 root_objectid,
5948                                      u64 flags, struct btrfs_disk_key *key,
5949                                      int level, struct btrfs_key *ins)
5950 {
5951         int ret;
5952         struct btrfs_fs_info *fs_info = root->fs_info;
5953         struct btrfs_extent_item *extent_item;
5954         struct btrfs_tree_block_info *block_info;
5955         struct btrfs_extent_inline_ref *iref;
5956         struct btrfs_path *path;
5957         struct extent_buffer *leaf;
5958         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
5959
5960         path = btrfs_alloc_path();
5961         if (!path)
5962                 return -ENOMEM;
5963
5964         path->leave_spinning = 1;
5965         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5966                                       ins, size);
5967         BUG_ON(ret);
5968
5969         leaf = path->nodes[0];
5970         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5971                                      struct btrfs_extent_item);
5972         btrfs_set_extent_refs(leaf, extent_item, 1);
5973         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5974         btrfs_set_extent_flags(leaf, extent_item,
5975                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
5976         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
5977
5978         btrfs_set_tree_block_key(leaf, block_info, key);
5979         btrfs_set_tree_block_level(leaf, block_info, level);
5980
5981         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
5982         if (parent > 0) {
5983                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
5984                 btrfs_set_extent_inline_ref_type(leaf, iref,
5985                                                  BTRFS_SHARED_BLOCK_REF_KEY);
5986                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5987         } else {
5988                 btrfs_set_extent_inline_ref_type(leaf, iref,
5989                                                  BTRFS_TREE_BLOCK_REF_KEY);
5990                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
5991         }
5992
5993         btrfs_mark_buffer_dirty(leaf);
5994         btrfs_free_path(path);
5995
5996         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5997         if (ret) {
5998                 printk(KERN_ERR "btrfs update block group failed for %llu "
5999                        "%llu\n", (unsigned long long)ins->objectid,
6000                        (unsigned long long)ins->offset);
6001                 BUG();
6002         }
6003         return ret;
6004 }
6005
6006 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6007                                      struct btrfs_root *root,
6008                                      u64 root_objectid, u64 owner,
6009                                      u64 offset, struct btrfs_key *ins)
6010 {
6011         int ret;
6012
6013         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6014
6015         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6016                                          ins->offset, 0,
6017                                          root_objectid, owner, offset,
6018                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6019         return ret;
6020 }
6021
6022 /*
6023  * this is used by the tree logging recovery code.  It records that
6024  * an extent has been allocated and makes sure to clear the free
6025  * space cache bits as well
6026  */
6027 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6028                                    struct btrfs_root *root,
6029                                    u64 root_objectid, u64 owner, u64 offset,
6030                                    struct btrfs_key *ins)
6031 {
6032         int ret;
6033         struct btrfs_block_group_cache *block_group;
6034         struct btrfs_caching_control *caching_ctl;
6035         u64 start = ins->objectid;
6036         u64 num_bytes = ins->offset;
6037
6038         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6039         cache_block_group(block_group, trans, NULL, 0);
6040         caching_ctl = get_caching_control(block_group);
6041
6042         if (!caching_ctl) {
6043                 BUG_ON(!block_group_cache_done(block_group));
6044                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6045                 BUG_ON(ret);
6046         } else {
6047                 mutex_lock(&caching_ctl->mutex);
6048
6049                 if (start >= caching_ctl->progress) {
6050                         ret = add_excluded_extent(root, start, num_bytes);
6051                         BUG_ON(ret);
6052                 } else if (start + num_bytes <= caching_ctl->progress) {
6053                         ret = btrfs_remove_free_space(block_group,
6054                                                       start, num_bytes);
6055                         BUG_ON(ret);
6056                 } else {
6057                         num_bytes = caching_ctl->progress - start;
6058                         ret = btrfs_remove_free_space(block_group,
6059                                                       start, num_bytes);
6060                         BUG_ON(ret);
6061
6062                         start = caching_ctl->progress;
6063                         num_bytes = ins->objectid + ins->offset -
6064                                     caching_ctl->progress;
6065                         ret = add_excluded_extent(root, start, num_bytes);
6066                         BUG_ON(ret);
6067                 }
6068
6069                 mutex_unlock(&caching_ctl->mutex);
6070                 put_caching_control(caching_ctl);
6071         }
6072
6073         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6074                                           RESERVE_ALLOC_NO_ACCOUNT);
6075         BUG_ON(ret);
6076         btrfs_put_block_group(block_group);
6077         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6078                                          0, owner, offset, ins, 1);
6079         return ret;
6080 }
6081
6082 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
6083                                             struct btrfs_root *root,
6084                                             u64 bytenr, u32 blocksize,
6085                                             int level)
6086 {
6087         struct extent_buffer *buf;
6088
6089         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6090         if (!buf)
6091                 return ERR_PTR(-ENOMEM);
6092         btrfs_set_header_generation(buf, trans->transid);
6093         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6094         btrfs_tree_lock(buf);
6095         clean_tree_block(trans, root, buf);
6096
6097         btrfs_set_lock_blocking(buf);
6098         btrfs_set_buffer_uptodate(buf);
6099
6100         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6101                 /*
6102                  * we allow two log transactions at a time, use different
6103                  * EXENT bit to differentiate dirty pages.
6104                  */
6105                 if (root->log_transid % 2 == 0)
6106                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6107                                         buf->start + buf->len - 1, GFP_NOFS);
6108                 else
6109                         set_extent_new(&root->dirty_log_pages, buf->start,
6110                                         buf->start + buf->len - 1, GFP_NOFS);
6111         } else {
6112                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6113                          buf->start + buf->len - 1, GFP_NOFS);
6114         }
6115         trans->blocks_used++;
6116         /* this returns a buffer locked for blocking */
6117         return buf;
6118 }
6119
6120 static struct btrfs_block_rsv *
6121 use_block_rsv(struct btrfs_trans_handle *trans,
6122               struct btrfs_root *root, u32 blocksize)
6123 {
6124         struct btrfs_block_rsv *block_rsv;
6125         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6126         int ret;
6127
6128         block_rsv = get_block_rsv(trans, root);
6129
6130         if (block_rsv->size == 0) {
6131                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6132                 /*
6133                  * If we couldn't reserve metadata bytes try and use some from
6134                  * the global reserve.
6135                  */
6136                 if (ret && block_rsv != global_rsv) {
6137                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6138                         if (!ret)
6139                                 return global_rsv;
6140                         return ERR_PTR(ret);
6141                 } else if (ret) {
6142                         return ERR_PTR(ret);
6143                 }
6144                 return block_rsv;
6145         }
6146
6147         ret = block_rsv_use_bytes(block_rsv, blocksize);
6148         if (!ret)
6149                 return block_rsv;
6150         if (ret) {
6151                 static DEFINE_RATELIMIT_STATE(_rs,
6152                                 DEFAULT_RATELIMIT_INTERVAL,
6153                                 /*DEFAULT_RATELIMIT_BURST*/ 2);
6154                 if (__ratelimit(&_rs)) {
6155                         printk(KERN_DEBUG "btrfs: block rsv returned %d\n", ret);
6156                         WARN_ON(1);
6157                 }
6158                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6159                 if (!ret) {
6160                         return block_rsv;
6161                 } else if (ret && block_rsv != global_rsv) {
6162                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6163                         if (!ret)
6164                                 return global_rsv;
6165                 }
6166         }
6167
6168         return ERR_PTR(-ENOSPC);
6169 }
6170
6171 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6172                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6173 {
6174         block_rsv_add_bytes(block_rsv, blocksize, 0);
6175         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6176 }
6177
6178 /*
6179  * finds a free extent and does all the dirty work required for allocation
6180  * returns the key for the extent through ins, and a tree buffer for
6181  * the first block of the extent through buf.
6182  *
6183  * returns the tree buffer or NULL.
6184  */
6185 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6186                                         struct btrfs_root *root, u32 blocksize,
6187                                         u64 parent, u64 root_objectid,
6188                                         struct btrfs_disk_key *key, int level,
6189                                         u64 hint, u64 empty_size, int for_cow)
6190 {
6191         struct btrfs_key ins;
6192         struct btrfs_block_rsv *block_rsv;
6193         struct extent_buffer *buf;
6194         u64 flags = 0;
6195         int ret;
6196
6197
6198         block_rsv = use_block_rsv(trans, root, blocksize);
6199         if (IS_ERR(block_rsv))
6200                 return ERR_CAST(block_rsv);
6201
6202         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6203                                    empty_size, hint, (u64)-1, &ins, 0);
6204         if (ret) {
6205                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
6206                 return ERR_PTR(ret);
6207         }
6208
6209         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6210                                     blocksize, level);
6211         BUG_ON(IS_ERR(buf));
6212
6213         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6214                 if (parent == 0)
6215                         parent = ins.objectid;
6216                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6217         } else
6218                 BUG_ON(parent > 0);
6219
6220         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6221                 struct btrfs_delayed_extent_op *extent_op;
6222                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
6223                 BUG_ON(!extent_op);
6224                 if (key)
6225                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6226                 else
6227                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6228                 extent_op->flags_to_set = flags;
6229                 extent_op->update_key = 1;
6230                 extent_op->update_flags = 1;
6231                 extent_op->is_data = 0;
6232
6233                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6234                                         ins.objectid,
6235                                         ins.offset, parent, root_objectid,
6236                                         level, BTRFS_ADD_DELAYED_EXTENT,
6237                                         extent_op, for_cow);
6238                 BUG_ON(ret);
6239         }
6240         return buf;
6241 }
6242
6243 struct walk_control {
6244         u64 refs[BTRFS_MAX_LEVEL];
6245         u64 flags[BTRFS_MAX_LEVEL];
6246         struct btrfs_key update_progress;
6247         int stage;
6248         int level;
6249         int shared_level;
6250         int update_ref;
6251         int keep_locks;
6252         int reada_slot;
6253         int reada_count;
6254         int for_reloc;
6255 };
6256
6257 #define DROP_REFERENCE  1
6258 #define UPDATE_BACKREF  2
6259
6260 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6261                                      struct btrfs_root *root,
6262                                      struct walk_control *wc,
6263                                      struct btrfs_path *path)
6264 {
6265         u64 bytenr;
6266         u64 generation;
6267         u64 refs;
6268         u64 flags;
6269         u32 nritems;
6270         u32 blocksize;
6271         struct btrfs_key key;
6272         struct extent_buffer *eb;
6273         int ret;
6274         int slot;
6275         int nread = 0;
6276
6277         if (path->slots[wc->level] < wc->reada_slot) {
6278                 wc->reada_count = wc->reada_count * 2 / 3;
6279                 wc->reada_count = max(wc->reada_count, 2);
6280         } else {
6281                 wc->reada_count = wc->reada_count * 3 / 2;
6282                 wc->reada_count = min_t(int, wc->reada_count,
6283                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6284         }
6285
6286         eb = path->nodes[wc->level];
6287         nritems = btrfs_header_nritems(eb);
6288         blocksize = btrfs_level_size(root, wc->level - 1);
6289
6290         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6291                 if (nread >= wc->reada_count)
6292                         break;
6293
6294                 cond_resched();
6295                 bytenr = btrfs_node_blockptr(eb, slot);
6296                 generation = btrfs_node_ptr_generation(eb, slot);
6297
6298                 if (slot == path->slots[wc->level])
6299                         goto reada;
6300
6301                 if (wc->stage == UPDATE_BACKREF &&
6302                     generation <= root->root_key.offset)
6303                         continue;
6304
6305                 /* We don't lock the tree block, it's OK to be racy here */
6306                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6307                                                &refs, &flags);
6308                 BUG_ON(ret);
6309                 BUG_ON(refs == 0);
6310
6311                 if (wc->stage == DROP_REFERENCE) {
6312                         if (refs == 1)
6313                                 goto reada;
6314
6315                         if (wc->level == 1 &&
6316                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6317                                 continue;
6318                         if (!wc->update_ref ||
6319                             generation <= root->root_key.offset)
6320                                 continue;
6321                         btrfs_node_key_to_cpu(eb, &key, slot);
6322                         ret = btrfs_comp_cpu_keys(&key,
6323                                                   &wc->update_progress);
6324                         if (ret < 0)
6325                                 continue;
6326                 } else {
6327                         if (wc->level == 1 &&
6328                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6329                                 continue;
6330                 }
6331 reada:
6332                 ret = readahead_tree_block(root, bytenr, blocksize,
6333                                            generation);
6334                 if (ret)
6335                         break;
6336                 nread++;
6337         }
6338         wc->reada_slot = slot;
6339 }
6340
6341 /*
6342  * hepler to process tree block while walking down the tree.
6343  *
6344  * when wc->stage == UPDATE_BACKREF, this function updates
6345  * back refs for pointers in the block.
6346  *
6347  * NOTE: return value 1 means we should stop walking down.
6348  */
6349 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
6350                                    struct btrfs_root *root,
6351                                    struct btrfs_path *path,
6352                                    struct walk_control *wc, int lookup_info)
6353 {
6354         int level = wc->level;
6355         struct extent_buffer *eb = path->nodes[level];
6356         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6357         int ret;
6358
6359         if (wc->stage == UPDATE_BACKREF &&
6360             btrfs_header_owner(eb) != root->root_key.objectid)
6361                 return 1;
6362
6363         /*
6364          * when reference count of tree block is 1, it won't increase
6365          * again. once full backref flag is set, we never clear it.
6366          */
6367         if (lookup_info &&
6368             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
6369              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
6370                 BUG_ON(!path->locks[level]);
6371                 ret = btrfs_lookup_extent_info(trans, root,
6372                                                eb->start, eb->len,
6373                                                &wc->refs[level],
6374                                                &wc->flags[level]);
6375                 BUG_ON(ret);
6376                 BUG_ON(wc->refs[level] == 0);
6377         }
6378
6379         if (wc->stage == DROP_REFERENCE) {
6380                 if (wc->refs[level] > 1)
6381                         return 1;
6382
6383                 if (path->locks[level] && !wc->keep_locks) {
6384                         btrfs_tree_unlock_rw(eb, path->locks[level]);
6385                         path->locks[level] = 0;
6386                 }
6387                 return 0;
6388         }
6389
6390         /* wc->stage == UPDATE_BACKREF */
6391         if (!(wc->flags[level] & flag)) {
6392                 BUG_ON(!path->locks[level]);
6393                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
6394                 BUG_ON(ret);
6395                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
6396                 BUG_ON(ret);
6397                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
6398                                                   eb->len, flag, 0);
6399                 BUG_ON(ret);
6400                 wc->flags[level] |= flag;
6401         }
6402
6403         /*
6404          * the block is shared by multiple trees, so it's not good to
6405          * keep the tree lock
6406          */
6407         if (path->locks[level] && level > 0) {
6408                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6409                 path->locks[level] = 0;
6410         }
6411         return 0;
6412 }
6413
6414 /*
6415  * hepler to process tree block pointer.
6416  *
6417  * when wc->stage == DROP_REFERENCE, this function checks
6418  * reference count of the block pointed to. if the block
6419  * is shared and we need update back refs for the subtree
6420  * rooted at the block, this function changes wc->stage to
6421  * UPDATE_BACKREF. if the block is shared and there is no
6422  * need to update back, this function drops the reference
6423  * to the block.
6424  *
6425  * NOTE: return value 1 means we should stop walking down.
6426  */
6427 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
6428                                  struct btrfs_root *root,
6429                                  struct btrfs_path *path,
6430                                  struct walk_control *wc, int *lookup_info)
6431 {
6432         u64 bytenr;
6433         u64 generation;
6434         u64 parent;
6435         u32 blocksize;
6436         struct btrfs_key key;
6437         struct extent_buffer *next;
6438         int level = wc->level;
6439         int reada = 0;
6440         int ret = 0;
6441
6442         generation = btrfs_node_ptr_generation(path->nodes[level],
6443                                                path->slots[level]);
6444         /*
6445          * if the lower level block was created before the snapshot
6446          * was created, we know there is no need to update back refs
6447          * for the subtree
6448          */
6449         if (wc->stage == UPDATE_BACKREF &&
6450             generation <= root->root_key.offset) {
6451                 *lookup_info = 1;
6452                 return 1;
6453         }
6454
6455         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6456         blocksize = btrfs_level_size(root, level - 1);
6457
6458         next = btrfs_find_tree_block(root, bytenr, blocksize);
6459         if (!next) {
6460                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6461                 if (!next)
6462                         return -ENOMEM;
6463                 reada = 1;
6464         }
6465         btrfs_tree_lock(next);
6466         btrfs_set_lock_blocking(next);
6467
6468         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6469                                        &wc->refs[level - 1],
6470                                        &wc->flags[level - 1]);
6471         BUG_ON(ret);
6472         BUG_ON(wc->refs[level - 1] == 0);
6473         *lookup_info = 0;
6474
6475         if (wc->stage == DROP_REFERENCE) {
6476                 if (wc->refs[level - 1] > 1) {
6477                         if (level == 1 &&
6478                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6479                                 goto skip;
6480
6481                         if (!wc->update_ref ||
6482                             generation <= root->root_key.offset)
6483                                 goto skip;
6484
6485                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6486                                               path->slots[level]);
6487                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6488                         if (ret < 0)
6489                                 goto skip;
6490
6491                         wc->stage = UPDATE_BACKREF;
6492                         wc->shared_level = level - 1;
6493                 }
6494         } else {
6495                 if (level == 1 &&
6496                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6497                         goto skip;
6498         }
6499
6500         if (!btrfs_buffer_uptodate(next, generation)) {
6501                 btrfs_tree_unlock(next);
6502                 free_extent_buffer(next);
6503                 next = NULL;
6504                 *lookup_info = 1;
6505         }
6506
6507         if (!next) {
6508                 if (reada && level == 1)
6509                         reada_walk_down(trans, root, wc, path);
6510                 next = read_tree_block(root, bytenr, blocksize, generation);
6511                 if (!next)
6512                         return -EIO;
6513                 btrfs_tree_lock(next);
6514                 btrfs_set_lock_blocking(next);
6515         }
6516
6517         level--;
6518         BUG_ON(level != btrfs_header_level(next));
6519         path->nodes[level] = next;
6520         path->slots[level] = 0;
6521         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6522         wc->level = level;
6523         if (wc->level == 1)
6524                 wc->reada_slot = 0;
6525         return 0;
6526 skip:
6527         wc->refs[level - 1] = 0;
6528         wc->flags[level - 1] = 0;
6529         if (wc->stage == DROP_REFERENCE) {
6530                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6531                         parent = path->nodes[level]->start;
6532                 } else {
6533                         BUG_ON(root->root_key.objectid !=
6534                                btrfs_header_owner(path->nodes[level]));
6535                         parent = 0;
6536                 }
6537
6538                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6539                                 root->root_key.objectid, level - 1, 0, 0);
6540                 BUG_ON(ret);
6541         }
6542         btrfs_tree_unlock(next);
6543         free_extent_buffer(next);
6544         *lookup_info = 1;
6545         return 1;
6546 }
6547
6548 /*
6549  * hepler to process tree block while walking up the tree.
6550  *
6551  * when wc->stage == DROP_REFERENCE, this function drops
6552  * reference count on the block.
6553  *
6554  * when wc->stage == UPDATE_BACKREF, this function changes
6555  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6556  * to UPDATE_BACKREF previously while processing the block.
6557  *
6558  * NOTE: return value 1 means we should stop walking up.
6559  */
6560 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6561                                  struct btrfs_root *root,
6562                                  struct btrfs_path *path,
6563                                  struct walk_control *wc)
6564 {
6565         int ret;
6566         int level = wc->level;
6567         struct extent_buffer *eb = path->nodes[level];
6568         u64 parent = 0;
6569
6570         if (wc->stage == UPDATE_BACKREF) {
6571                 BUG_ON(wc->shared_level < level);
6572                 if (level < wc->shared_level)
6573                         goto out;
6574
6575                 ret = find_next_key(path, level + 1, &wc->update_progress);
6576                 if (ret > 0)
6577                         wc->update_ref = 0;
6578
6579                 wc->stage = DROP_REFERENCE;
6580                 wc->shared_level = -1;
6581                 path->slots[level] = 0;
6582
6583                 /*
6584                  * check reference count again if the block isn't locked.
6585                  * we should start walking down the tree again if reference
6586                  * count is one.
6587                  */
6588                 if (!path->locks[level]) {
6589                         BUG_ON(level == 0);
6590                         btrfs_tree_lock(eb);
6591                         btrfs_set_lock_blocking(eb);
6592                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6593
6594                         ret = btrfs_lookup_extent_info(trans, root,
6595                                                        eb->start, eb->len,
6596                                                        &wc->refs[level],
6597                                                        &wc->flags[level]);
6598                         BUG_ON(ret);
6599                         BUG_ON(wc->refs[level] == 0);
6600                         if (wc->refs[level] == 1) {
6601                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6602                                 return 1;
6603                         }
6604                 }
6605         }
6606
6607         /* wc->stage == DROP_REFERENCE */
6608         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6609
6610         if (wc->refs[level] == 1) {
6611                 if (level == 0) {
6612                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6613                                 ret = btrfs_dec_ref(trans, root, eb, 1,
6614                                                     wc->for_reloc);
6615                         else
6616                                 ret = btrfs_dec_ref(trans, root, eb, 0,
6617                                                     wc->for_reloc);
6618                         BUG_ON(ret);
6619                 }
6620                 /* make block locked assertion in clean_tree_block happy */
6621                 if (!path->locks[level] &&
6622                     btrfs_header_generation(eb) == trans->transid) {
6623                         btrfs_tree_lock(eb);
6624                         btrfs_set_lock_blocking(eb);
6625                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6626                 }
6627                 clean_tree_block(trans, root, eb);
6628         }
6629
6630         if (eb == root->node) {
6631                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6632                         parent = eb->start;
6633                 else
6634                         BUG_ON(root->root_key.objectid !=
6635                                btrfs_header_owner(eb));
6636         } else {
6637                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6638                         parent = path->nodes[level + 1]->start;
6639                 else
6640                         BUG_ON(root->root_key.objectid !=
6641                                btrfs_header_owner(path->nodes[level + 1]));
6642         }
6643
6644         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1, 0);
6645 out:
6646         wc->refs[level] = 0;
6647         wc->flags[level] = 0;
6648         return 0;
6649 }
6650
6651 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6652                                    struct btrfs_root *root,
6653                                    struct btrfs_path *path,
6654                                    struct walk_control *wc)
6655 {
6656         int level = wc->level;
6657         int lookup_info = 1;
6658         int ret;
6659
6660         while (level >= 0) {
6661                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6662                 if (ret > 0)
6663                         break;
6664
6665                 if (level == 0)
6666                         break;
6667
6668                 if (path->slots[level] >=
6669                     btrfs_header_nritems(path->nodes[level]))
6670                         break;
6671
6672                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6673                 if (ret > 0) {
6674                         path->slots[level]++;
6675                         continue;
6676                 } else if (ret < 0)
6677                         return ret;
6678                 level = wc->level;
6679         }
6680         return 0;
6681 }
6682
6683 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6684                                  struct btrfs_root *root,
6685                                  struct btrfs_path *path,
6686                                  struct walk_control *wc, int max_level)
6687 {
6688         int level = wc->level;
6689         int ret;
6690
6691         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6692         while (level < max_level && path->nodes[level]) {
6693                 wc->level = level;
6694                 if (path->slots[level] + 1 <
6695                     btrfs_header_nritems(path->nodes[level])) {
6696                         path->slots[level]++;
6697                         return 0;
6698                 } else {
6699                         ret = walk_up_proc(trans, root, path, wc);
6700                         if (ret > 0)
6701                                 return 0;
6702
6703                         if (path->locks[level]) {
6704                                 btrfs_tree_unlock_rw(path->nodes[level],
6705                                                      path->locks[level]);
6706                                 path->locks[level] = 0;
6707                         }
6708                         free_extent_buffer(path->nodes[level]);
6709                         path->nodes[level] = NULL;
6710                         level++;
6711                 }
6712         }
6713         return 1;
6714 }
6715
6716 /*
6717  * drop a subvolume tree.
6718  *
6719  * this function traverses the tree freeing any blocks that only
6720  * referenced by the tree.
6721  *
6722  * when a shared tree block is found. this function decreases its
6723  * reference count by one. if update_ref is true, this function
6724  * also make sure backrefs for the shared block and all lower level
6725  * blocks are properly updated.
6726  */
6727 void btrfs_drop_snapshot(struct btrfs_root *root,
6728                          struct btrfs_block_rsv *block_rsv, int update_ref,
6729                          int for_reloc)
6730 {
6731         struct btrfs_path *path;
6732         struct btrfs_trans_handle *trans;
6733         struct btrfs_root *tree_root = root->fs_info->tree_root;
6734         struct btrfs_root_item *root_item = &root->root_item;
6735         struct walk_control *wc;
6736         struct btrfs_key key;
6737         int err = 0;
6738         int ret;
6739         int level;
6740
6741         path = btrfs_alloc_path();
6742         if (!path) {
6743                 err = -ENOMEM;
6744                 goto out;
6745         }
6746
6747         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6748         if (!wc) {
6749                 btrfs_free_path(path);
6750                 err = -ENOMEM;
6751                 goto out;
6752         }
6753
6754         trans = btrfs_start_transaction(tree_root, 0);
6755         BUG_ON(IS_ERR(trans));
6756
6757         if (block_rsv)
6758                 trans->block_rsv = block_rsv;
6759
6760         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6761                 level = btrfs_header_level(root->node);
6762                 path->nodes[level] = btrfs_lock_root_node(root);
6763                 btrfs_set_lock_blocking(path->nodes[level]);
6764                 path->slots[level] = 0;
6765                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6766                 memset(&wc->update_progress, 0,
6767                        sizeof(wc->update_progress));
6768         } else {
6769                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6770                 memcpy(&wc->update_progress, &key,
6771                        sizeof(wc->update_progress));
6772
6773                 level = root_item->drop_level;
6774                 BUG_ON(level == 0);
6775                 path->lowest_level = level;
6776                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6777                 path->lowest_level = 0;
6778                 if (ret < 0) {
6779                         err = ret;
6780                         goto out_free;
6781                 }
6782                 WARN_ON(ret > 0);
6783
6784                 /*
6785                  * unlock our path, this is safe because only this
6786                  * function is allowed to delete this snapshot
6787                  */
6788                 btrfs_unlock_up_safe(path, 0);
6789
6790                 level = btrfs_header_level(root->node);
6791                 while (1) {
6792                         btrfs_tree_lock(path->nodes[level]);
6793                         btrfs_set_lock_blocking(path->nodes[level]);
6794
6795                         ret = btrfs_lookup_extent_info(trans, root,
6796                                                 path->nodes[level]->start,
6797                                                 path->nodes[level]->len,
6798                                                 &wc->refs[level],
6799                                                 &wc->flags[level]);
6800                         BUG_ON(ret);
6801                         BUG_ON(wc->refs[level] == 0);
6802
6803                         if (level == root_item->drop_level)
6804                                 break;
6805
6806                         btrfs_tree_unlock(path->nodes[level]);
6807                         WARN_ON(wc->refs[level] != 1);
6808                         level--;
6809                 }
6810         }
6811
6812         wc->level = level;
6813         wc->shared_level = -1;
6814         wc->stage = DROP_REFERENCE;
6815         wc->update_ref = update_ref;
6816         wc->keep_locks = 0;
6817         wc->for_reloc = for_reloc;
6818         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6819
6820         while (1) {
6821                 ret = walk_down_tree(trans, root, path, wc);
6822                 if (ret < 0) {
6823                         err = ret;
6824                         break;
6825                 }
6826
6827                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
6828                 if (ret < 0) {
6829                         err = ret;
6830                         break;
6831                 }
6832
6833                 if (ret > 0) {
6834                         BUG_ON(wc->stage != DROP_REFERENCE);
6835                         break;
6836                 }
6837
6838                 if (wc->stage == DROP_REFERENCE) {
6839                         level = wc->level;
6840                         btrfs_node_key(path->nodes[level],
6841                                        &root_item->drop_progress,
6842                                        path->slots[level]);
6843                         root_item->drop_level = level;
6844                 }
6845
6846                 BUG_ON(wc->level == 0);
6847                 if (btrfs_should_end_transaction(trans, tree_root)) {
6848                         ret = btrfs_update_root(trans, tree_root,
6849                                                 &root->root_key,
6850                                                 root_item);
6851                         BUG_ON(ret);
6852
6853                         btrfs_end_transaction_throttle(trans, tree_root);
6854                         trans = btrfs_start_transaction(tree_root, 0);
6855                         BUG_ON(IS_ERR(trans));
6856                         if (block_rsv)
6857                                 trans->block_rsv = block_rsv;
6858                 }
6859         }
6860         btrfs_release_path(path);
6861         BUG_ON(err);
6862
6863         ret = btrfs_del_root(trans, tree_root, &root->root_key);
6864         BUG_ON(ret);
6865
6866         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
6867                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
6868                                            NULL, NULL);
6869                 BUG_ON(ret < 0);
6870                 if (ret > 0) {
6871                         /* if we fail to delete the orphan item this time
6872                          * around, it'll get picked up the next time.
6873                          *
6874                          * The most common failure here is just -ENOENT.
6875                          */
6876                         btrfs_del_orphan_item(trans, tree_root,
6877                                               root->root_key.objectid);
6878                 }
6879         }
6880
6881         if (root->in_radix) {
6882                 btrfs_free_fs_root(tree_root->fs_info, root);
6883         } else {
6884                 free_extent_buffer(root->node);
6885                 free_extent_buffer(root->commit_root);
6886                 kfree(root);
6887         }
6888 out_free:
6889         btrfs_end_transaction_throttle(trans, tree_root);
6890         kfree(wc);
6891         btrfs_free_path(path);
6892 out:
6893         if (err)
6894                 btrfs_std_error(root->fs_info, err);
6895         return;
6896 }
6897
6898 /*
6899  * drop subtree rooted at tree block 'node'.
6900  *
6901  * NOTE: this function will unlock and release tree block 'node'
6902  * only used by relocation code
6903  */
6904 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6905                         struct btrfs_root *root,
6906                         struct extent_buffer *node,
6907                         struct extent_buffer *parent)
6908 {
6909         struct btrfs_path *path;
6910         struct walk_control *wc;
6911         int level;
6912         int parent_level;
6913         int ret = 0;
6914         int wret;
6915
6916         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6917
6918         path = btrfs_alloc_path();
6919         if (!path)
6920                 return -ENOMEM;
6921
6922         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6923         if (!wc) {
6924                 btrfs_free_path(path);
6925                 return -ENOMEM;
6926         }
6927
6928         btrfs_assert_tree_locked(parent);
6929         parent_level = btrfs_header_level(parent);
6930         extent_buffer_get(parent);
6931         path->nodes[parent_level] = parent;
6932         path->slots[parent_level] = btrfs_header_nritems(parent);
6933
6934         btrfs_assert_tree_locked(node);
6935         level = btrfs_header_level(node);
6936         path->nodes[level] = node;
6937         path->slots[level] = 0;
6938         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6939
6940         wc->refs[parent_level] = 1;
6941         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6942         wc->level = level;
6943         wc->shared_level = -1;
6944         wc->stage = DROP_REFERENCE;
6945         wc->update_ref = 0;
6946         wc->keep_locks = 1;
6947         wc->for_reloc = 1;
6948         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6949
6950         while (1) {
6951                 wret = walk_down_tree(trans, root, path, wc);
6952                 if (wret < 0) {
6953                         ret = wret;
6954                         break;
6955                 }
6956
6957                 wret = walk_up_tree(trans, root, path, wc, parent_level);
6958                 if (wret < 0)
6959                         ret = wret;
6960                 if (wret != 0)
6961                         break;
6962         }
6963
6964         kfree(wc);
6965         btrfs_free_path(path);
6966         return ret;
6967 }
6968
6969 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
6970 {
6971         u64 num_devices;
6972         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
6973                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
6974
6975         if (root->fs_info->balance_ctl) {
6976                 struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
6977                 u64 tgt = 0;
6978
6979                 /* pick restriper's target profile and return */
6980                 if (flags & BTRFS_BLOCK_GROUP_DATA &&
6981                     bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
6982                         tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
6983                 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
6984                            bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
6985                         tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
6986                 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
6987                            bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
6988                         tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
6989                 }
6990
6991                 if (tgt) {
6992                         /* extended -> chunk profile */
6993                         tgt &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
6994                         return tgt;
6995                 }
6996         }
6997
6998         /*
6999          * we add in the count of missing devices because we want
7000          * to make sure that any RAID levels on a degraded FS
7001          * continue to be honored.
7002          */
7003         num_devices = root->fs_info->fs_devices->rw_devices +
7004                 root->fs_info->fs_devices->missing_devices;
7005
7006         if (num_devices == 1) {
7007                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7008                 stripped = flags & ~stripped;
7009
7010                 /* turn raid0 into single device chunks */
7011                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7012                         return stripped;
7013
7014                 /* turn mirroring into duplication */
7015                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7016                              BTRFS_BLOCK_GROUP_RAID10))
7017                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7018                 return flags;
7019         } else {
7020                 /* they already had raid on here, just return */
7021                 if (flags & stripped)
7022                         return flags;
7023
7024                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7025                 stripped = flags & ~stripped;
7026
7027                 /* switch duplicated blocks with raid1 */
7028                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7029                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7030
7031                 /* turn single device chunks into raid0 */
7032                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
7033         }
7034         return flags;
7035 }
7036
7037 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7038 {
7039         struct btrfs_space_info *sinfo = cache->space_info;
7040         u64 num_bytes;
7041         u64 min_allocable_bytes;
7042         int ret = -ENOSPC;
7043
7044
7045         /*
7046          * We need some metadata space and system metadata space for
7047          * allocating chunks in some corner cases until we force to set
7048          * it to be readonly.
7049          */
7050         if ((sinfo->flags &
7051              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7052             !force)
7053                 min_allocable_bytes = 1 * 1024 * 1024;
7054         else
7055                 min_allocable_bytes = 0;
7056
7057         spin_lock(&sinfo->lock);
7058         spin_lock(&cache->lock);
7059
7060         if (cache->ro) {
7061                 ret = 0;
7062                 goto out;
7063         }
7064
7065         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7066                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7067
7068         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7069             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7070             min_allocable_bytes <= sinfo->total_bytes) {
7071                 sinfo->bytes_readonly += num_bytes;
7072                 cache->ro = 1;
7073                 ret = 0;
7074         }
7075 out:
7076         spin_unlock(&cache->lock);
7077         spin_unlock(&sinfo->lock);
7078         return ret;
7079 }
7080
7081 int btrfs_set_block_group_ro(struct btrfs_root *root,
7082                              struct btrfs_block_group_cache *cache)
7083
7084 {
7085         struct btrfs_trans_handle *trans;
7086         u64 alloc_flags;
7087         int ret;
7088
7089         BUG_ON(cache->ro);
7090
7091         trans = btrfs_join_transaction(root);
7092         BUG_ON(IS_ERR(trans));
7093
7094         alloc_flags = update_block_group_flags(root, cache->flags);
7095         if (alloc_flags != cache->flags)
7096                 do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7097                                CHUNK_ALLOC_FORCE);
7098
7099         ret = set_block_group_ro(cache, 0);
7100         if (!ret)
7101                 goto out;
7102         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7103         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7104                              CHUNK_ALLOC_FORCE);
7105         if (ret < 0)
7106                 goto out;
7107         ret = set_block_group_ro(cache, 0);
7108 out:
7109         btrfs_end_transaction(trans, root);
7110         return ret;
7111 }
7112
7113 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7114                             struct btrfs_root *root, u64 type)
7115 {
7116         u64 alloc_flags = get_alloc_profile(root, type);
7117         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
7118                               CHUNK_ALLOC_FORCE);
7119 }
7120
7121 /*
7122  * helper to account the unused space of all the readonly block group in the
7123  * list. takes mirrors into account.
7124  */
7125 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
7126 {
7127         struct btrfs_block_group_cache *block_group;
7128         u64 free_bytes = 0;
7129         int factor;
7130
7131         list_for_each_entry(block_group, groups_list, list) {
7132                 spin_lock(&block_group->lock);
7133
7134                 if (!block_group->ro) {
7135                         spin_unlock(&block_group->lock);
7136                         continue;
7137                 }
7138
7139                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
7140                                           BTRFS_BLOCK_GROUP_RAID10 |
7141                                           BTRFS_BLOCK_GROUP_DUP))
7142                         factor = 2;
7143                 else
7144                         factor = 1;
7145
7146                 free_bytes += (block_group->key.offset -
7147                                btrfs_block_group_used(&block_group->item)) *
7148                                factor;
7149
7150                 spin_unlock(&block_group->lock);
7151         }
7152
7153         return free_bytes;
7154 }
7155
7156 /*
7157  * helper to account the unused space of all the readonly block group in the
7158  * space_info. takes mirrors into account.
7159  */
7160 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7161 {
7162         int i;
7163         u64 free_bytes = 0;
7164
7165         spin_lock(&sinfo->lock);
7166
7167         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7168                 if (!list_empty(&sinfo->block_groups[i]))
7169                         free_bytes += __btrfs_get_ro_block_group_free_space(
7170                                                 &sinfo->block_groups[i]);
7171
7172         spin_unlock(&sinfo->lock);
7173
7174         return free_bytes;
7175 }
7176
7177 int btrfs_set_block_group_rw(struct btrfs_root *root,
7178                               struct btrfs_block_group_cache *cache)
7179 {
7180         struct btrfs_space_info *sinfo = cache->space_info;
7181         u64 num_bytes;
7182
7183         BUG_ON(!cache->ro);
7184
7185         spin_lock(&sinfo->lock);
7186         spin_lock(&cache->lock);
7187         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7188                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7189         sinfo->bytes_readonly -= num_bytes;
7190         cache->ro = 0;
7191         spin_unlock(&cache->lock);
7192         spin_unlock(&sinfo->lock);
7193         return 0;
7194 }
7195
7196 /*
7197  * checks to see if its even possible to relocate this block group.
7198  *
7199  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7200  * ok to go ahead and try.
7201  */
7202 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7203 {
7204         struct btrfs_block_group_cache *block_group;
7205         struct btrfs_space_info *space_info;
7206         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7207         struct btrfs_device *device;
7208         u64 min_free;
7209         u64 dev_min = 1;
7210         u64 dev_nr = 0;
7211         int index;
7212         int full = 0;
7213         int ret = 0;
7214
7215         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7216
7217         /* odd, couldn't find the block group, leave it alone */
7218         if (!block_group)
7219                 return -1;
7220
7221         min_free = btrfs_block_group_used(&block_group->item);
7222
7223         /* no bytes used, we're good */
7224         if (!min_free)
7225                 goto out;
7226
7227         space_info = block_group->space_info;
7228         spin_lock(&space_info->lock);
7229
7230         full = space_info->full;
7231
7232         /*
7233          * if this is the last block group we have in this space, we can't
7234          * relocate it unless we're able to allocate a new chunk below.
7235          *
7236          * Otherwise, we need to make sure we have room in the space to handle
7237          * all of the extents from this block group.  If we can, we're good
7238          */
7239         if ((space_info->total_bytes != block_group->key.offset) &&
7240             (space_info->bytes_used + space_info->bytes_reserved +
7241              space_info->bytes_pinned + space_info->bytes_readonly +
7242              min_free < space_info->total_bytes)) {
7243                 spin_unlock(&space_info->lock);
7244                 goto out;
7245         }
7246         spin_unlock(&space_info->lock);
7247
7248         /*
7249          * ok we don't have enough space, but maybe we have free space on our
7250          * devices to allocate new chunks for relocation, so loop through our
7251          * alloc devices and guess if we have enough space.  However, if we
7252          * were marked as full, then we know there aren't enough chunks, and we
7253          * can just return.
7254          */
7255         ret = -1;
7256         if (full)
7257                 goto out;
7258
7259         /*
7260          * index:
7261          *      0: raid10
7262          *      1: raid1
7263          *      2: dup
7264          *      3: raid0
7265          *      4: single
7266          */
7267         index = get_block_group_index(block_group);
7268         if (index == 0) {
7269                 dev_min = 4;
7270                 /* Divide by 2 */
7271                 min_free >>= 1;
7272         } else if (index == 1) {
7273                 dev_min = 2;
7274         } else if (index == 2) {
7275                 /* Multiply by 2 */
7276                 min_free <<= 1;
7277         } else if (index == 3) {
7278                 dev_min = fs_devices->rw_devices;
7279                 do_div(min_free, dev_min);
7280         }
7281
7282         mutex_lock(&root->fs_info->chunk_mutex);
7283         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7284                 u64 dev_offset;
7285
7286                 /*
7287                  * check to make sure we can actually find a chunk with enough
7288                  * space to fit our block group in.
7289                  */
7290                 if (device->total_bytes > device->bytes_used + min_free) {
7291                         ret = find_free_dev_extent(device, min_free,
7292                                                    &dev_offset, NULL);
7293                         if (!ret)
7294                                 dev_nr++;
7295
7296                         if (dev_nr >= dev_min)
7297                                 break;
7298
7299                         ret = -1;
7300                 }
7301         }
7302         mutex_unlock(&root->fs_info->chunk_mutex);
7303 out:
7304         btrfs_put_block_group(block_group);
7305         return ret;
7306 }
7307
7308 static int find_first_block_group(struct btrfs_root *root,
7309                 struct btrfs_path *path, struct btrfs_key *key)
7310 {
7311         int ret = 0;
7312         struct btrfs_key found_key;
7313         struct extent_buffer *leaf;
7314         int slot;
7315
7316         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7317         if (ret < 0)
7318                 goto out;
7319
7320         while (1) {
7321                 slot = path->slots[0];
7322                 leaf = path->nodes[0];
7323                 if (slot >= btrfs_header_nritems(leaf)) {
7324                         ret = btrfs_next_leaf(root, path);
7325                         if (ret == 0)
7326                                 continue;
7327                         if (ret < 0)
7328                                 goto out;
7329                         break;
7330                 }
7331                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7332
7333                 if (found_key.objectid >= key->objectid &&
7334                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7335                         ret = 0;
7336                         goto out;
7337                 }
7338                 path->slots[0]++;
7339         }
7340 out:
7341         return ret;
7342 }
7343
7344 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7345 {
7346         struct btrfs_block_group_cache *block_group;
7347         u64 last = 0;
7348
7349         while (1) {
7350                 struct inode *inode;
7351
7352                 block_group = btrfs_lookup_first_block_group(info, last);
7353                 while (block_group) {
7354                         spin_lock(&block_group->lock);
7355                         if (block_group->iref)
7356                                 break;
7357                         spin_unlock(&block_group->lock);
7358                         block_group = next_block_group(info->tree_root,
7359                                                        block_group);
7360                 }
7361                 if (!block_group) {
7362                         if (last == 0)
7363                                 break;
7364                         last = 0;
7365                         continue;
7366                 }
7367
7368                 inode = block_group->inode;
7369                 block_group->iref = 0;
7370                 block_group->inode = NULL;
7371                 spin_unlock(&block_group->lock);
7372                 iput(inode);
7373                 last = block_group->key.objectid + block_group->key.offset;
7374                 btrfs_put_block_group(block_group);
7375         }
7376 }
7377
7378 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7379 {
7380         struct btrfs_block_group_cache *block_group;
7381         struct btrfs_space_info *space_info;
7382         struct btrfs_caching_control *caching_ctl;
7383         struct rb_node *n;
7384
7385         down_write(&info->extent_commit_sem);
7386         while (!list_empty(&info->caching_block_groups)) {
7387                 caching_ctl = list_entry(info->caching_block_groups.next,
7388                                          struct btrfs_caching_control, list);
7389                 list_del(&caching_ctl->list);
7390                 put_caching_control(caching_ctl);
7391         }
7392         up_write(&info->extent_commit_sem);
7393
7394         spin_lock(&info->block_group_cache_lock);
7395         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7396                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7397                                        cache_node);
7398                 rb_erase(&block_group->cache_node,
7399                          &info->block_group_cache_tree);
7400                 spin_unlock(&info->block_group_cache_lock);
7401
7402                 down_write(&block_group->space_info->groups_sem);
7403                 list_del(&block_group->list);
7404                 up_write(&block_group->space_info->groups_sem);
7405
7406                 if (block_group->cached == BTRFS_CACHE_STARTED)
7407                         wait_block_group_cache_done(block_group);
7408
7409                 /*
7410                  * We haven't cached this block group, which means we could
7411                  * possibly have excluded extents on this block group.
7412                  */
7413                 if (block_group->cached == BTRFS_CACHE_NO)
7414                         free_excluded_extents(info->extent_root, block_group);
7415
7416                 btrfs_remove_free_space_cache(block_group);
7417                 btrfs_put_block_group(block_group);
7418
7419                 spin_lock(&info->block_group_cache_lock);
7420         }
7421         spin_unlock(&info->block_group_cache_lock);
7422
7423         /* now that all the block groups are freed, go through and
7424          * free all the space_info structs.  This is only called during
7425          * the final stages of unmount, and so we know nobody is
7426          * using them.  We call synchronize_rcu() once before we start,
7427          * just to be on the safe side.
7428          */
7429         synchronize_rcu();
7430
7431         release_global_block_rsv(info);
7432
7433         while(!list_empty(&info->space_info)) {
7434                 space_info = list_entry(info->space_info.next,
7435                                         struct btrfs_space_info,
7436                                         list);
7437                 if (space_info->bytes_pinned > 0 ||
7438                     space_info->bytes_reserved > 0 ||
7439                     space_info->bytes_may_use > 0) {
7440                         WARN_ON(1);
7441                         dump_space_info(space_info, 0, 0);
7442                 }
7443                 list_del(&space_info->list);
7444                 kfree(space_info);
7445         }
7446         return 0;
7447 }
7448
7449 static void __link_block_group(struct btrfs_space_info *space_info,
7450                                struct btrfs_block_group_cache *cache)
7451 {
7452         int index = get_block_group_index(cache);
7453
7454         down_write(&space_info->groups_sem);
7455         list_add_tail(&cache->list, &space_info->block_groups[index]);
7456         up_write(&space_info->groups_sem);
7457 }
7458
7459 int btrfs_read_block_groups(struct btrfs_root *root)
7460 {
7461         struct btrfs_path *path;
7462         int ret;
7463         struct btrfs_block_group_cache *cache;
7464         struct btrfs_fs_info *info = root->fs_info;
7465         struct btrfs_space_info *space_info;
7466         struct btrfs_key key;
7467         struct btrfs_key found_key;
7468         struct extent_buffer *leaf;
7469         int need_clear = 0;
7470         u64 cache_gen;
7471
7472         root = info->extent_root;
7473         key.objectid = 0;
7474         key.offset = 0;
7475         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
7476         path = btrfs_alloc_path();
7477         if (!path)
7478                 return -ENOMEM;
7479         path->reada = 1;
7480
7481         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
7482         if (btrfs_test_opt(root, SPACE_CACHE) &&
7483             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
7484                 need_clear = 1;
7485         if (btrfs_test_opt(root, CLEAR_CACHE))
7486                 need_clear = 1;
7487
7488         while (1) {
7489                 ret = find_first_block_group(root, path, &key);
7490                 if (ret > 0)
7491                         break;
7492                 if (ret != 0)
7493                         goto error;
7494                 leaf = path->nodes[0];
7495                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
7496                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
7497                 if (!cache) {
7498                         ret = -ENOMEM;
7499                         goto error;
7500                 }
7501                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7502                                                 GFP_NOFS);
7503                 if (!cache->free_space_ctl) {
7504                         kfree(cache);
7505                         ret = -ENOMEM;
7506                         goto error;
7507                 }
7508
7509                 atomic_set(&cache->count, 1);
7510                 spin_lock_init(&cache->lock);
7511                 cache->fs_info = info;
7512                 INIT_LIST_HEAD(&cache->list);
7513                 INIT_LIST_HEAD(&cache->cluster_list);
7514
7515                 if (need_clear)
7516                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7517
7518                 read_extent_buffer(leaf, &cache->item,
7519                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7520                                    sizeof(cache->item));
7521                 memcpy(&cache->key, &found_key, sizeof(found_key));
7522
7523                 key.objectid = found_key.objectid + found_key.offset;
7524                 btrfs_release_path(path);
7525                 cache->flags = btrfs_block_group_flags(&cache->item);
7526                 cache->sectorsize = root->sectorsize;
7527
7528                 btrfs_init_free_space_ctl(cache);
7529
7530                 /*
7531                  * We need to exclude the super stripes now so that the space
7532                  * info has super bytes accounted for, otherwise we'll think
7533                  * we have more space than we actually do.
7534                  */
7535                 exclude_super_stripes(root, cache);
7536
7537                 /*
7538                  * check for two cases, either we are full, and therefore
7539                  * don't need to bother with the caching work since we won't
7540                  * find any space, or we are empty, and we can just add all
7541                  * the space in and be done with it.  This saves us _alot_ of
7542                  * time, particularly in the full case.
7543                  */
7544                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7545                         cache->last_byte_to_unpin = (u64)-1;
7546                         cache->cached = BTRFS_CACHE_FINISHED;
7547                         free_excluded_extents(root, cache);
7548                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7549                         cache->last_byte_to_unpin = (u64)-1;
7550                         cache->cached = BTRFS_CACHE_FINISHED;
7551                         add_new_free_space(cache, root->fs_info,
7552                                            found_key.objectid,
7553                                            found_key.objectid +
7554                                            found_key.offset);
7555                         free_excluded_extents(root, cache);
7556                 }
7557
7558                 ret = update_space_info(info, cache->flags, found_key.offset,
7559                                         btrfs_block_group_used(&cache->item),
7560                                         &space_info);
7561                 BUG_ON(ret);
7562                 cache->space_info = space_info;
7563                 spin_lock(&cache->space_info->lock);
7564                 cache->space_info->bytes_readonly += cache->bytes_super;
7565                 spin_unlock(&cache->space_info->lock);
7566
7567                 __link_block_group(space_info, cache);
7568
7569                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7570                 BUG_ON(ret);
7571
7572                 set_avail_alloc_bits(root->fs_info, cache->flags);
7573                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7574                         set_block_group_ro(cache, 1);
7575         }
7576
7577         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7578                 if (!(get_alloc_profile(root, space_info->flags) &
7579                       (BTRFS_BLOCK_GROUP_RAID10 |
7580                        BTRFS_BLOCK_GROUP_RAID1 |
7581                        BTRFS_BLOCK_GROUP_DUP)))
7582                         continue;
7583                 /*
7584                  * avoid allocating from un-mirrored block group if there are
7585                  * mirrored block groups.
7586                  */
7587                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7588                         set_block_group_ro(cache, 1);
7589                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7590                         set_block_group_ro(cache, 1);
7591         }
7592
7593         init_global_block_rsv(info);
7594         ret = 0;
7595 error:
7596         btrfs_free_path(path);
7597         return ret;
7598 }
7599
7600 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7601                            struct btrfs_root *root, u64 bytes_used,
7602                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7603                            u64 size)
7604 {
7605         int ret;
7606         struct btrfs_root *extent_root;
7607         struct btrfs_block_group_cache *cache;
7608
7609         extent_root = root->fs_info->extent_root;
7610
7611         root->fs_info->last_trans_log_full_commit = trans->transid;
7612
7613         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7614         if (!cache)
7615                 return -ENOMEM;
7616         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7617                                         GFP_NOFS);
7618         if (!cache->free_space_ctl) {
7619                 kfree(cache);
7620                 return -ENOMEM;
7621         }
7622
7623         cache->key.objectid = chunk_offset;
7624         cache->key.offset = size;
7625         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7626         cache->sectorsize = root->sectorsize;
7627         cache->fs_info = root->fs_info;
7628
7629         atomic_set(&cache->count, 1);
7630         spin_lock_init(&cache->lock);
7631         INIT_LIST_HEAD(&cache->list);
7632         INIT_LIST_HEAD(&cache->cluster_list);
7633
7634         btrfs_init_free_space_ctl(cache);
7635
7636         btrfs_set_block_group_used(&cache->item, bytes_used);
7637         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7638         cache->flags = type;
7639         btrfs_set_block_group_flags(&cache->item, type);
7640
7641         cache->last_byte_to_unpin = (u64)-1;
7642         cache->cached = BTRFS_CACHE_FINISHED;
7643         exclude_super_stripes(root, cache);
7644
7645         add_new_free_space(cache, root->fs_info, chunk_offset,
7646                            chunk_offset + size);
7647
7648         free_excluded_extents(root, cache);
7649
7650         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7651                                 &cache->space_info);
7652         BUG_ON(ret);
7653         update_global_block_rsv(root->fs_info);
7654
7655         spin_lock(&cache->space_info->lock);
7656         cache->space_info->bytes_readonly += cache->bytes_super;
7657         spin_unlock(&cache->space_info->lock);
7658
7659         __link_block_group(cache->space_info, cache);
7660
7661         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7662         BUG_ON(ret);
7663
7664         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7665                                 sizeof(cache->item));
7666         BUG_ON(ret);
7667
7668         set_avail_alloc_bits(extent_root->fs_info, type);
7669
7670         return 0;
7671 }
7672
7673 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
7674 {
7675         u64 extra_flags = flags & BTRFS_BLOCK_GROUP_PROFILE_MASK;
7676
7677         /* chunk -> extended profile */
7678         if (extra_flags == 0)
7679                 extra_flags = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
7680
7681         if (flags & BTRFS_BLOCK_GROUP_DATA)
7682                 fs_info->avail_data_alloc_bits &= ~extra_flags;
7683         if (flags & BTRFS_BLOCK_GROUP_METADATA)
7684                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
7685         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
7686                 fs_info->avail_system_alloc_bits &= ~extra_flags;
7687 }
7688
7689 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7690                              struct btrfs_root *root, u64 group_start)
7691 {
7692         struct btrfs_path *path;
7693         struct btrfs_block_group_cache *block_group;
7694         struct btrfs_free_cluster *cluster;
7695         struct btrfs_root *tree_root = root->fs_info->tree_root;
7696         struct btrfs_key key;
7697         struct inode *inode;
7698         int ret;
7699         int index;
7700         int factor;
7701
7702         root = root->fs_info->extent_root;
7703
7704         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7705         BUG_ON(!block_group);
7706         BUG_ON(!block_group->ro);
7707
7708         /*
7709          * Free the reserved super bytes from this block group before
7710          * remove it.
7711          */
7712         free_excluded_extents(root, block_group);
7713
7714         memcpy(&key, &block_group->key, sizeof(key));
7715         index = get_block_group_index(block_group);
7716         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7717                                   BTRFS_BLOCK_GROUP_RAID1 |
7718                                   BTRFS_BLOCK_GROUP_RAID10))
7719                 factor = 2;
7720         else
7721                 factor = 1;
7722
7723         /* make sure this block group isn't part of an allocation cluster */
7724         cluster = &root->fs_info->data_alloc_cluster;
7725         spin_lock(&cluster->refill_lock);
7726         btrfs_return_cluster_to_free_space(block_group, cluster);
7727         spin_unlock(&cluster->refill_lock);
7728
7729         /*
7730          * make sure this block group isn't part of a metadata
7731          * allocation cluster
7732          */
7733         cluster = &root->fs_info->meta_alloc_cluster;
7734         spin_lock(&cluster->refill_lock);
7735         btrfs_return_cluster_to_free_space(block_group, cluster);
7736         spin_unlock(&cluster->refill_lock);
7737
7738         path = btrfs_alloc_path();
7739         if (!path) {
7740                 ret = -ENOMEM;
7741                 goto out;
7742         }
7743
7744         inode = lookup_free_space_inode(tree_root, block_group, path);
7745         if (!IS_ERR(inode)) {
7746                 ret = btrfs_orphan_add(trans, inode);
7747                 BUG_ON(ret);
7748                 clear_nlink(inode);
7749                 /* One for the block groups ref */
7750                 spin_lock(&block_group->lock);
7751                 if (block_group->iref) {
7752                         block_group->iref = 0;
7753                         block_group->inode = NULL;
7754                         spin_unlock(&block_group->lock);
7755                         iput(inode);
7756                 } else {
7757                         spin_unlock(&block_group->lock);
7758                 }
7759                 /* One for our lookup ref */
7760                 btrfs_add_delayed_iput(inode);
7761         }
7762
7763         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7764         key.offset = block_group->key.objectid;
7765         key.type = 0;
7766
7767         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7768         if (ret < 0)
7769                 goto out;
7770         if (ret > 0)
7771                 btrfs_release_path(path);
7772         if (ret == 0) {
7773                 ret = btrfs_del_item(trans, tree_root, path);
7774                 if (ret)
7775                         goto out;
7776                 btrfs_release_path(path);
7777         }
7778
7779         spin_lock(&root->fs_info->block_group_cache_lock);
7780         rb_erase(&block_group->cache_node,
7781                  &root->fs_info->block_group_cache_tree);
7782         spin_unlock(&root->fs_info->block_group_cache_lock);
7783
7784         down_write(&block_group->space_info->groups_sem);
7785         /*
7786          * we must use list_del_init so people can check to see if they
7787          * are still on the list after taking the semaphore
7788          */
7789         list_del_init(&block_group->list);
7790         if (list_empty(&block_group->space_info->block_groups[index]))
7791                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
7792         up_write(&block_group->space_info->groups_sem);
7793
7794         if (block_group->cached == BTRFS_CACHE_STARTED)
7795                 wait_block_group_cache_done(block_group);
7796
7797         btrfs_remove_free_space_cache(block_group);
7798
7799         spin_lock(&block_group->space_info->lock);
7800         block_group->space_info->total_bytes -= block_group->key.offset;
7801         block_group->space_info->bytes_readonly -= block_group->key.offset;
7802         block_group->space_info->disk_total -= block_group->key.offset * factor;
7803         spin_unlock(&block_group->space_info->lock);
7804
7805         memcpy(&key, &block_group->key, sizeof(key));
7806
7807         btrfs_clear_space_info_full(root->fs_info);
7808
7809         btrfs_put_block_group(block_group);
7810         btrfs_put_block_group(block_group);
7811
7812         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
7813         if (ret > 0)
7814                 ret = -EIO;
7815         if (ret < 0)
7816                 goto out;
7817
7818         ret = btrfs_del_item(trans, root, path);
7819 out:
7820         btrfs_free_path(path);
7821         return ret;
7822 }
7823
7824 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
7825 {
7826         struct btrfs_space_info *space_info;
7827         struct btrfs_super_block *disk_super;
7828         u64 features;
7829         u64 flags;
7830         int mixed = 0;
7831         int ret;
7832
7833         disk_super = fs_info->super_copy;
7834         if (!btrfs_super_root(disk_super))
7835                 return 1;
7836
7837         features = btrfs_super_incompat_flags(disk_super);
7838         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
7839                 mixed = 1;
7840
7841         flags = BTRFS_BLOCK_GROUP_SYSTEM;
7842         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7843         if (ret)
7844                 goto out;
7845
7846         if (mixed) {
7847                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
7848                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7849         } else {
7850                 flags = BTRFS_BLOCK_GROUP_METADATA;
7851                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7852                 if (ret)
7853                         goto out;
7854
7855                 flags = BTRFS_BLOCK_GROUP_DATA;
7856                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7857         }
7858 out:
7859         return ret;
7860 }
7861
7862 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
7863 {
7864         return unpin_extent_range(root, start, end);
7865 }
7866
7867 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
7868                                u64 num_bytes, u64 *actual_bytes)
7869 {
7870         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
7871 }
7872
7873 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
7874 {
7875         struct btrfs_fs_info *fs_info = root->fs_info;
7876         struct btrfs_block_group_cache *cache = NULL;
7877         u64 group_trimmed;
7878         u64 start;
7879         u64 end;
7880         u64 trimmed = 0;
7881         int ret = 0;
7882
7883         cache = btrfs_lookup_block_group(fs_info, range->start);
7884
7885         while (cache) {
7886                 if (cache->key.objectid >= (range->start + range->len)) {
7887                         btrfs_put_block_group(cache);
7888                         break;
7889                 }
7890
7891                 start = max(range->start, cache->key.objectid);
7892                 end = min(range->start + range->len,
7893                                 cache->key.objectid + cache->key.offset);
7894
7895                 if (end - start >= range->minlen) {
7896                         if (!block_group_cache_done(cache)) {
7897                                 ret = cache_block_group(cache, NULL, root, 0);
7898                                 if (!ret)
7899                                         wait_block_group_cache_done(cache);
7900                         }
7901                         ret = btrfs_trim_block_group(cache,
7902                                                      &group_trimmed,
7903                                                      start,
7904                                                      end,
7905                                                      range->minlen);
7906
7907                         trimmed += group_trimmed;
7908                         if (ret) {
7909                                 btrfs_put_block_group(cache);
7910                                 break;
7911                         }
7912                 }
7913
7914                 cache = next_block_group(fs_info->tree_root, cache);
7915         }
7916
7917         range->len = trimmed;
7918         return ret;
7919 }