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)
1875 {
1876         int ret;
1877         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1878                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1879
1880         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1881                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
1882                                         parent, root_objectid, (int)owner,
1883                                         BTRFS_ADD_DELAYED_REF, NULL);
1884         } else {
1885                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
1886                                         parent, root_objectid, owner, offset,
1887                                         BTRFS_ADD_DELAYED_REF, NULL);
1888         }
1889         return ret;
1890 }
1891
1892 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1893                                   struct btrfs_root *root,
1894                                   u64 bytenr, u64 num_bytes,
1895                                   u64 parent, u64 root_objectid,
1896                                   u64 owner, u64 offset, int refs_to_add,
1897                                   struct btrfs_delayed_extent_op *extent_op)
1898 {
1899         struct btrfs_path *path;
1900         struct extent_buffer *leaf;
1901         struct btrfs_extent_item *item;
1902         u64 refs;
1903         int ret;
1904         int err = 0;
1905
1906         path = btrfs_alloc_path();
1907         if (!path)
1908                 return -ENOMEM;
1909
1910         path->reada = 1;
1911         path->leave_spinning = 1;
1912         /* this will setup the path even if it fails to insert the back ref */
1913         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1914                                            path, bytenr, num_bytes, parent,
1915                                            root_objectid, owner, offset,
1916                                            refs_to_add, extent_op);
1917         if (ret == 0)
1918                 goto out;
1919
1920         if (ret != -EAGAIN) {
1921                 err = ret;
1922                 goto out;
1923         }
1924
1925         leaf = path->nodes[0];
1926         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1927         refs = btrfs_extent_refs(leaf, item);
1928         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1929         if (extent_op)
1930                 __run_delayed_extent_op(extent_op, leaf, item);
1931
1932         btrfs_mark_buffer_dirty(leaf);
1933         btrfs_release_path(path);
1934
1935         path->reada = 1;
1936         path->leave_spinning = 1;
1937
1938         /* now insert the actual backref */
1939         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1940                                     path, bytenr, parent, root_objectid,
1941                                     owner, offset, refs_to_add);
1942         BUG_ON(ret);
1943 out:
1944         btrfs_free_path(path);
1945         return err;
1946 }
1947
1948 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1949                                 struct btrfs_root *root,
1950                                 struct btrfs_delayed_ref_node *node,
1951                                 struct btrfs_delayed_extent_op *extent_op,
1952                                 int insert_reserved)
1953 {
1954         int ret = 0;
1955         struct btrfs_delayed_data_ref *ref;
1956         struct btrfs_key ins;
1957         u64 parent = 0;
1958         u64 ref_root = 0;
1959         u64 flags = 0;
1960
1961         ins.objectid = node->bytenr;
1962         ins.offset = node->num_bytes;
1963         ins.type = BTRFS_EXTENT_ITEM_KEY;
1964
1965         ref = btrfs_delayed_node_to_data_ref(node);
1966         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1967                 parent = ref->parent;
1968         else
1969                 ref_root = ref->root;
1970
1971         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1972                 if (extent_op) {
1973                         BUG_ON(extent_op->update_key);
1974                         flags |= extent_op->flags_to_set;
1975                 }
1976                 ret = alloc_reserved_file_extent(trans, root,
1977                                                  parent, ref_root, flags,
1978                                                  ref->objectid, ref->offset,
1979                                                  &ins, node->ref_mod);
1980         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1981                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
1982                                              node->num_bytes, parent,
1983                                              ref_root, ref->objectid,
1984                                              ref->offset, node->ref_mod,
1985                                              extent_op);
1986         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1987                 ret = __btrfs_free_extent(trans, root, node->bytenr,
1988                                           node->num_bytes, parent,
1989                                           ref_root, ref->objectid,
1990                                           ref->offset, node->ref_mod,
1991                                           extent_op);
1992         } else {
1993                 BUG();
1994         }
1995         return ret;
1996 }
1997
1998 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1999                                     struct extent_buffer *leaf,
2000                                     struct btrfs_extent_item *ei)
2001 {
2002         u64 flags = btrfs_extent_flags(leaf, ei);
2003         if (extent_op->update_flags) {
2004                 flags |= extent_op->flags_to_set;
2005                 btrfs_set_extent_flags(leaf, ei, flags);
2006         }
2007
2008         if (extent_op->update_key) {
2009                 struct btrfs_tree_block_info *bi;
2010                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2011                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2012                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2013         }
2014 }
2015
2016 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2017                                  struct btrfs_root *root,
2018                                  struct btrfs_delayed_ref_node *node,
2019                                  struct btrfs_delayed_extent_op *extent_op)
2020 {
2021         struct btrfs_key key;
2022         struct btrfs_path *path;
2023         struct btrfs_extent_item *ei;
2024         struct extent_buffer *leaf;
2025         u32 item_size;
2026         int ret;
2027         int err = 0;
2028
2029         path = btrfs_alloc_path();
2030         if (!path)
2031                 return -ENOMEM;
2032
2033         key.objectid = node->bytenr;
2034         key.type = BTRFS_EXTENT_ITEM_KEY;
2035         key.offset = node->num_bytes;
2036
2037         path->reada = 1;
2038         path->leave_spinning = 1;
2039         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2040                                 path, 0, 1);
2041         if (ret < 0) {
2042                 err = ret;
2043                 goto out;
2044         }
2045         if (ret > 0) {
2046                 err = -EIO;
2047                 goto out;
2048         }
2049
2050         leaf = path->nodes[0];
2051         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2052 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2053         if (item_size < sizeof(*ei)) {
2054                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2055                                              path, (u64)-1, 0);
2056                 if (ret < 0) {
2057                         err = ret;
2058                         goto out;
2059                 }
2060                 leaf = path->nodes[0];
2061                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2062         }
2063 #endif
2064         BUG_ON(item_size < sizeof(*ei));
2065         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2066         __run_delayed_extent_op(extent_op, leaf, ei);
2067
2068         btrfs_mark_buffer_dirty(leaf);
2069 out:
2070         btrfs_free_path(path);
2071         return err;
2072 }
2073
2074 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2075                                 struct btrfs_root *root,
2076                                 struct btrfs_delayed_ref_node *node,
2077                                 struct btrfs_delayed_extent_op *extent_op,
2078                                 int insert_reserved)
2079 {
2080         int ret = 0;
2081         struct btrfs_delayed_tree_ref *ref;
2082         struct btrfs_key ins;
2083         u64 parent = 0;
2084         u64 ref_root = 0;
2085
2086         ins.objectid = node->bytenr;
2087         ins.offset = node->num_bytes;
2088         ins.type = BTRFS_EXTENT_ITEM_KEY;
2089
2090         ref = btrfs_delayed_node_to_tree_ref(node);
2091         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2092                 parent = ref->parent;
2093         else
2094                 ref_root = ref->root;
2095
2096         BUG_ON(node->ref_mod != 1);
2097         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2098                 BUG_ON(!extent_op || !extent_op->update_flags ||
2099                        !extent_op->update_key);
2100                 ret = alloc_reserved_tree_block(trans, root,
2101                                                 parent, ref_root,
2102                                                 extent_op->flags_to_set,
2103                                                 &extent_op->key,
2104                                                 ref->level, &ins);
2105         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2106                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2107                                              node->num_bytes, parent, ref_root,
2108                                              ref->level, 0, 1, extent_op);
2109         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2110                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2111                                           node->num_bytes, parent, ref_root,
2112                                           ref->level, 0, 1, extent_op);
2113         } else {
2114                 BUG();
2115         }
2116         return ret;
2117 }
2118
2119 /* helper function to actually process a single delayed ref entry */
2120 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2121                                struct btrfs_root *root,
2122                                struct btrfs_delayed_ref_node *node,
2123                                struct btrfs_delayed_extent_op *extent_op,
2124                                int insert_reserved)
2125 {
2126         int ret;
2127         if (btrfs_delayed_ref_is_head(node)) {
2128                 struct btrfs_delayed_ref_head *head;
2129                 /*
2130                  * we've hit the end of the chain and we were supposed
2131                  * to insert this extent into the tree.  But, it got
2132                  * deleted before we ever needed to insert it, so all
2133                  * we have to do is clean up the accounting
2134                  */
2135                 BUG_ON(extent_op);
2136                 head = btrfs_delayed_node_to_head(node);
2137                 if (insert_reserved) {
2138                         btrfs_pin_extent(root, node->bytenr,
2139                                          node->num_bytes, 1);
2140                         if (head->is_data) {
2141                                 ret = btrfs_del_csums(trans, root,
2142                                                       node->bytenr,
2143                                                       node->num_bytes);
2144                                 BUG_ON(ret);
2145                         }
2146                 }
2147                 mutex_unlock(&head->mutex);
2148                 return 0;
2149         }
2150
2151         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2152             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2153                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2154                                            insert_reserved);
2155         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2156                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2157                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2158                                            insert_reserved);
2159         else
2160                 BUG();
2161         return ret;
2162 }
2163
2164 static noinline struct btrfs_delayed_ref_node *
2165 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2166 {
2167         struct rb_node *node;
2168         struct btrfs_delayed_ref_node *ref;
2169         int action = BTRFS_ADD_DELAYED_REF;
2170 again:
2171         /*
2172          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2173          * this prevents ref count from going down to zero when
2174          * there still are pending delayed ref.
2175          */
2176         node = rb_prev(&head->node.rb_node);
2177         while (1) {
2178                 if (!node)
2179                         break;
2180                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2181                                 rb_node);
2182                 if (ref->bytenr != head->node.bytenr)
2183                         break;
2184                 if (ref->action == action)
2185                         return ref;
2186                 node = rb_prev(node);
2187         }
2188         if (action == BTRFS_ADD_DELAYED_REF) {
2189                 action = BTRFS_DROP_DELAYED_REF;
2190                 goto again;
2191         }
2192         return NULL;
2193 }
2194
2195 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2196                                        struct btrfs_root *root,
2197                                        struct list_head *cluster)
2198 {
2199         struct btrfs_delayed_ref_root *delayed_refs;
2200         struct btrfs_delayed_ref_node *ref;
2201         struct btrfs_delayed_ref_head *locked_ref = NULL;
2202         struct btrfs_delayed_extent_op *extent_op;
2203         int ret;
2204         int count = 0;
2205         int must_insert_reserved = 0;
2206
2207         delayed_refs = &trans->transaction->delayed_refs;
2208         while (1) {
2209                 if (!locked_ref) {
2210                         /* pick a new head ref from the cluster list */
2211                         if (list_empty(cluster))
2212                                 break;
2213
2214                         locked_ref = list_entry(cluster->next,
2215                                      struct btrfs_delayed_ref_head, cluster);
2216
2217                         /* grab the lock that says we are going to process
2218                          * all the refs for this head */
2219                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2220
2221                         /*
2222                          * we may have dropped the spin lock to get the head
2223                          * mutex lock, and that might have given someone else
2224                          * time to free the head.  If that's true, it has been
2225                          * removed from our list and we can move on.
2226                          */
2227                         if (ret == -EAGAIN) {
2228                                 locked_ref = NULL;
2229                                 count++;
2230                                 continue;
2231                         }
2232                 }
2233
2234                 /*
2235                  * record the must insert reserved flag before we
2236                  * drop the spin lock.
2237                  */
2238                 must_insert_reserved = locked_ref->must_insert_reserved;
2239                 locked_ref->must_insert_reserved = 0;
2240
2241                 extent_op = locked_ref->extent_op;
2242                 locked_ref->extent_op = NULL;
2243
2244                 /*
2245                  * locked_ref is the head node, so we have to go one
2246                  * node back for any delayed ref updates
2247                  */
2248                 ref = select_delayed_ref(locked_ref);
2249                 if (!ref) {
2250                         /* All delayed refs have been processed, Go ahead
2251                          * and send the head node to run_one_delayed_ref,
2252                          * so that any accounting fixes can happen
2253                          */
2254                         ref = &locked_ref->node;
2255
2256                         if (extent_op && must_insert_reserved) {
2257                                 kfree(extent_op);
2258                                 extent_op = NULL;
2259                         }
2260
2261                         if (extent_op) {
2262                                 spin_unlock(&delayed_refs->lock);
2263
2264                                 ret = run_delayed_extent_op(trans, root,
2265                                                             ref, extent_op);
2266                                 BUG_ON(ret);
2267                                 kfree(extent_op);
2268
2269                                 goto next;
2270                         }
2271
2272                         list_del_init(&locked_ref->cluster);
2273                         locked_ref = NULL;
2274                 }
2275
2276                 ref->in_tree = 0;
2277                 rb_erase(&ref->rb_node, &delayed_refs->root);
2278                 delayed_refs->num_entries--;
2279
2280                 spin_unlock(&delayed_refs->lock);
2281
2282                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2283                                           must_insert_reserved);
2284                 BUG_ON(ret);
2285
2286                 btrfs_put_delayed_ref(ref);
2287                 kfree(extent_op);
2288                 count++;
2289 next:
2290                 do_chunk_alloc(trans, root->fs_info->extent_root,
2291                                2 * 1024 * 1024,
2292                                btrfs_get_alloc_profile(root, 0),
2293                                CHUNK_ALLOC_NO_FORCE);
2294                 cond_resched();
2295                 spin_lock(&delayed_refs->lock);
2296         }
2297         return count;
2298 }
2299
2300 /*
2301  * this starts processing the delayed reference count updates and
2302  * extent insertions we have queued up so far.  count can be
2303  * 0, which means to process everything in the tree at the start
2304  * of the run (but not newly added entries), or it can be some target
2305  * number you'd like to process.
2306  */
2307 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2308                            struct btrfs_root *root, unsigned long count)
2309 {
2310         struct rb_node *node;
2311         struct btrfs_delayed_ref_root *delayed_refs;
2312         struct btrfs_delayed_ref_node *ref;
2313         struct list_head cluster;
2314         int ret;
2315         int run_all = count == (unsigned long)-1;
2316         int run_most = 0;
2317
2318         if (root == root->fs_info->extent_root)
2319                 root = root->fs_info->tree_root;
2320
2321         do_chunk_alloc(trans, root->fs_info->extent_root,
2322                        2 * 1024 * 1024, btrfs_get_alloc_profile(root, 0),
2323                        CHUNK_ALLOC_NO_FORCE);
2324
2325         delayed_refs = &trans->transaction->delayed_refs;
2326         INIT_LIST_HEAD(&cluster);
2327 again:
2328         spin_lock(&delayed_refs->lock);
2329         if (count == 0) {
2330                 count = delayed_refs->num_entries * 2;
2331                 run_most = 1;
2332         }
2333         while (1) {
2334                 if (!(run_all || run_most) &&
2335                     delayed_refs->num_heads_ready < 64)
2336                         break;
2337
2338                 /*
2339                  * go find something we can process in the rbtree.  We start at
2340                  * the beginning of the tree, and then build a cluster
2341                  * of refs to process starting at the first one we are able to
2342                  * lock
2343                  */
2344                 ret = btrfs_find_ref_cluster(trans, &cluster,
2345                                              delayed_refs->run_delayed_start);
2346                 if (ret)
2347                         break;
2348
2349                 ret = run_clustered_refs(trans, root, &cluster);
2350                 BUG_ON(ret < 0);
2351
2352                 count -= min_t(unsigned long, ret, count);
2353
2354                 if (count == 0)
2355                         break;
2356         }
2357
2358         if (run_all) {
2359                 node = rb_first(&delayed_refs->root);
2360                 if (!node)
2361                         goto out;
2362                 count = (unsigned long)-1;
2363
2364                 while (node) {
2365                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2366                                        rb_node);
2367                         if (btrfs_delayed_ref_is_head(ref)) {
2368                                 struct btrfs_delayed_ref_head *head;
2369
2370                                 head = btrfs_delayed_node_to_head(ref);
2371                                 atomic_inc(&ref->refs);
2372
2373                                 spin_unlock(&delayed_refs->lock);
2374                                 /*
2375                                  * Mutex was contended, block until it's
2376                                  * released and try again
2377                                  */
2378                                 mutex_lock(&head->mutex);
2379                                 mutex_unlock(&head->mutex);
2380
2381                                 btrfs_put_delayed_ref(ref);
2382                                 cond_resched();
2383                                 goto again;
2384                         }
2385                         node = rb_next(node);
2386                 }
2387                 spin_unlock(&delayed_refs->lock);
2388                 schedule_timeout(1);
2389                 goto again;
2390         }
2391 out:
2392         spin_unlock(&delayed_refs->lock);
2393         return 0;
2394 }
2395
2396 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2397                                 struct btrfs_root *root,
2398                                 u64 bytenr, u64 num_bytes, u64 flags,
2399                                 int is_data)
2400 {
2401         struct btrfs_delayed_extent_op *extent_op;
2402         int ret;
2403
2404         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2405         if (!extent_op)
2406                 return -ENOMEM;
2407
2408         extent_op->flags_to_set = flags;
2409         extent_op->update_flags = 1;
2410         extent_op->update_key = 0;
2411         extent_op->is_data = is_data ? 1 : 0;
2412
2413         ret = btrfs_add_delayed_extent_op(trans, bytenr, num_bytes, extent_op);
2414         if (ret)
2415                 kfree(extent_op);
2416         return ret;
2417 }
2418
2419 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2420                                       struct btrfs_root *root,
2421                                       struct btrfs_path *path,
2422                                       u64 objectid, u64 offset, u64 bytenr)
2423 {
2424         struct btrfs_delayed_ref_head *head;
2425         struct btrfs_delayed_ref_node *ref;
2426         struct btrfs_delayed_data_ref *data_ref;
2427         struct btrfs_delayed_ref_root *delayed_refs;
2428         struct rb_node *node;
2429         int ret = 0;
2430
2431         ret = -ENOENT;
2432         delayed_refs = &trans->transaction->delayed_refs;
2433         spin_lock(&delayed_refs->lock);
2434         head = btrfs_find_delayed_ref_head(trans, bytenr);
2435         if (!head)
2436                 goto out;
2437
2438         if (!mutex_trylock(&head->mutex)) {
2439                 atomic_inc(&head->node.refs);
2440                 spin_unlock(&delayed_refs->lock);
2441
2442                 btrfs_release_path(path);
2443
2444                 /*
2445                  * Mutex was contended, block until it's released and let
2446                  * caller try again
2447                  */
2448                 mutex_lock(&head->mutex);
2449                 mutex_unlock(&head->mutex);
2450                 btrfs_put_delayed_ref(&head->node);
2451                 return -EAGAIN;
2452         }
2453
2454         node = rb_prev(&head->node.rb_node);
2455         if (!node)
2456                 goto out_unlock;
2457
2458         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2459
2460         if (ref->bytenr != bytenr)
2461                 goto out_unlock;
2462
2463         ret = 1;
2464         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2465                 goto out_unlock;
2466
2467         data_ref = btrfs_delayed_node_to_data_ref(ref);
2468
2469         node = rb_prev(node);
2470         if (node) {
2471                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2472                 if (ref->bytenr == bytenr)
2473                         goto out_unlock;
2474         }
2475
2476         if (data_ref->root != root->root_key.objectid ||
2477             data_ref->objectid != objectid || data_ref->offset != offset)
2478                 goto out_unlock;
2479
2480         ret = 0;
2481 out_unlock:
2482         mutex_unlock(&head->mutex);
2483 out:
2484         spin_unlock(&delayed_refs->lock);
2485         return ret;
2486 }
2487
2488 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2489                                         struct btrfs_root *root,
2490                                         struct btrfs_path *path,
2491                                         u64 objectid, u64 offset, u64 bytenr)
2492 {
2493         struct btrfs_root *extent_root = root->fs_info->extent_root;
2494         struct extent_buffer *leaf;
2495         struct btrfs_extent_data_ref *ref;
2496         struct btrfs_extent_inline_ref *iref;
2497         struct btrfs_extent_item *ei;
2498         struct btrfs_key key;
2499         u32 item_size;
2500         int ret;
2501
2502         key.objectid = bytenr;
2503         key.offset = (u64)-1;
2504         key.type = BTRFS_EXTENT_ITEM_KEY;
2505
2506         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2507         if (ret < 0)
2508                 goto out;
2509         BUG_ON(ret == 0);
2510
2511         ret = -ENOENT;
2512         if (path->slots[0] == 0)
2513                 goto out;
2514
2515         path->slots[0]--;
2516         leaf = path->nodes[0];
2517         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2518
2519         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2520                 goto out;
2521
2522         ret = 1;
2523         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2524 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2525         if (item_size < sizeof(*ei)) {
2526                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2527                 goto out;
2528         }
2529 #endif
2530         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2531
2532         if (item_size != sizeof(*ei) +
2533             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2534                 goto out;
2535
2536         if (btrfs_extent_generation(leaf, ei) <=
2537             btrfs_root_last_snapshot(&root->root_item))
2538                 goto out;
2539
2540         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2541         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2542             BTRFS_EXTENT_DATA_REF_KEY)
2543                 goto out;
2544
2545         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2546         if (btrfs_extent_refs(leaf, ei) !=
2547             btrfs_extent_data_ref_count(leaf, ref) ||
2548             btrfs_extent_data_ref_root(leaf, ref) !=
2549             root->root_key.objectid ||
2550             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2551             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2552                 goto out;
2553
2554         ret = 0;
2555 out:
2556         return ret;
2557 }
2558
2559 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2560                           struct btrfs_root *root,
2561                           u64 objectid, u64 offset, u64 bytenr)
2562 {
2563         struct btrfs_path *path;
2564         int ret;
2565         int ret2;
2566
2567         path = btrfs_alloc_path();
2568         if (!path)
2569                 return -ENOENT;
2570
2571         do {
2572                 ret = check_committed_ref(trans, root, path, objectid,
2573                                           offset, bytenr);
2574                 if (ret && ret != -ENOENT)
2575                         goto out;
2576
2577                 ret2 = check_delayed_ref(trans, root, path, objectid,
2578                                          offset, bytenr);
2579         } while (ret2 == -EAGAIN);
2580
2581         if (ret2 && ret2 != -ENOENT) {
2582                 ret = ret2;
2583                 goto out;
2584         }
2585
2586         if (ret != -ENOENT || ret2 != -ENOENT)
2587                 ret = 0;
2588 out:
2589         btrfs_free_path(path);
2590         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
2591                 WARN_ON(ret > 0);
2592         return ret;
2593 }
2594
2595 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2596                            struct btrfs_root *root,
2597                            struct extent_buffer *buf,
2598                            int full_backref, int inc)
2599 {
2600         u64 bytenr;
2601         u64 num_bytes;
2602         u64 parent;
2603         u64 ref_root;
2604         u32 nritems;
2605         struct btrfs_key key;
2606         struct btrfs_file_extent_item *fi;
2607         int i;
2608         int level;
2609         int ret = 0;
2610         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
2611                             u64, u64, u64, u64, u64, u64);
2612
2613         ref_root = btrfs_header_owner(buf);
2614         nritems = btrfs_header_nritems(buf);
2615         level = btrfs_header_level(buf);
2616
2617         if (!root->ref_cows && level == 0)
2618                 return 0;
2619
2620         if (inc)
2621                 process_func = btrfs_inc_extent_ref;
2622         else
2623                 process_func = btrfs_free_extent;
2624
2625         if (full_backref)
2626                 parent = buf->start;
2627         else
2628                 parent = 0;
2629
2630         for (i = 0; i < nritems; i++) {
2631                 if (level == 0) {
2632                         btrfs_item_key_to_cpu(buf, &key, i);
2633                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
2634                                 continue;
2635                         fi = btrfs_item_ptr(buf, i,
2636                                             struct btrfs_file_extent_item);
2637                         if (btrfs_file_extent_type(buf, fi) ==
2638                             BTRFS_FILE_EXTENT_INLINE)
2639                                 continue;
2640                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2641                         if (bytenr == 0)
2642                                 continue;
2643
2644                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2645                         key.offset -= btrfs_file_extent_offset(buf, fi);
2646                         ret = process_func(trans, root, bytenr, num_bytes,
2647                                            parent, ref_root, key.objectid,
2648                                            key.offset);
2649                         if (ret)
2650                                 goto fail;
2651                 } else {
2652                         bytenr = btrfs_node_blockptr(buf, i);
2653                         num_bytes = btrfs_level_size(root, level - 1);
2654                         ret = process_func(trans, root, bytenr, num_bytes,
2655                                            parent, ref_root, level - 1, 0);
2656                         if (ret)
2657                                 goto fail;
2658                 }
2659         }
2660         return 0;
2661 fail:
2662         BUG();
2663         return ret;
2664 }
2665
2666 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2667                   struct extent_buffer *buf, int full_backref)
2668 {
2669         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2670 }
2671
2672 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2673                   struct extent_buffer *buf, int full_backref)
2674 {
2675         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2676 }
2677
2678 static int write_one_cache_group(struct btrfs_trans_handle *trans,
2679                                  struct btrfs_root *root,
2680                                  struct btrfs_path *path,
2681                                  struct btrfs_block_group_cache *cache)
2682 {
2683         int ret;
2684         struct btrfs_root *extent_root = root->fs_info->extent_root;
2685         unsigned long bi;
2686         struct extent_buffer *leaf;
2687
2688         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
2689         if (ret < 0)
2690                 goto fail;
2691         BUG_ON(ret);
2692
2693         leaf = path->nodes[0];
2694         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2695         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
2696         btrfs_mark_buffer_dirty(leaf);
2697         btrfs_release_path(path);
2698 fail:
2699         if (ret)
2700                 return ret;
2701         return 0;
2702
2703 }
2704
2705 static struct btrfs_block_group_cache *
2706 next_block_group(struct btrfs_root *root,
2707                  struct btrfs_block_group_cache *cache)
2708 {
2709         struct rb_node *node;
2710         spin_lock(&root->fs_info->block_group_cache_lock);
2711         node = rb_next(&cache->cache_node);
2712         btrfs_put_block_group(cache);
2713         if (node) {
2714                 cache = rb_entry(node, struct btrfs_block_group_cache,
2715                                  cache_node);
2716                 btrfs_get_block_group(cache);
2717         } else
2718                 cache = NULL;
2719         spin_unlock(&root->fs_info->block_group_cache_lock);
2720         return cache;
2721 }
2722
2723 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
2724                             struct btrfs_trans_handle *trans,
2725                             struct btrfs_path *path)
2726 {
2727         struct btrfs_root *root = block_group->fs_info->tree_root;
2728         struct inode *inode = NULL;
2729         u64 alloc_hint = 0;
2730         int dcs = BTRFS_DC_ERROR;
2731         int num_pages = 0;
2732         int retries = 0;
2733         int ret = 0;
2734
2735         /*
2736          * If this block group is smaller than 100 megs don't bother caching the
2737          * block group.
2738          */
2739         if (block_group->key.offset < (100 * 1024 * 1024)) {
2740                 spin_lock(&block_group->lock);
2741                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2742                 spin_unlock(&block_group->lock);
2743                 return 0;
2744         }
2745
2746 again:
2747         inode = lookup_free_space_inode(root, block_group, path);
2748         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2749                 ret = PTR_ERR(inode);
2750                 btrfs_release_path(path);
2751                 goto out;
2752         }
2753
2754         if (IS_ERR(inode)) {
2755                 BUG_ON(retries);
2756                 retries++;
2757
2758                 if (block_group->ro)
2759                         goto out_free;
2760
2761                 ret = create_free_space_inode(root, trans, block_group, path);
2762                 if (ret)
2763                         goto out_free;
2764                 goto again;
2765         }
2766
2767         /* We've already setup this transaction, go ahead and exit */
2768         if (block_group->cache_generation == trans->transid &&
2769             i_size_read(inode)) {
2770                 dcs = BTRFS_DC_SETUP;
2771                 goto out_put;
2772         }
2773
2774         /*
2775          * We want to set the generation to 0, that way if anything goes wrong
2776          * from here on out we know not to trust this cache when we load up next
2777          * time.
2778          */
2779         BTRFS_I(inode)->generation = 0;
2780         ret = btrfs_update_inode(trans, root, inode);
2781         WARN_ON(ret);
2782
2783         if (i_size_read(inode) > 0) {
2784                 ret = btrfs_truncate_free_space_cache(root, trans, path,
2785                                                       inode);
2786                 if (ret)
2787                         goto out_put;
2788         }
2789
2790         spin_lock(&block_group->lock);
2791         if (block_group->cached != BTRFS_CACHE_FINISHED) {
2792                 /* We're not cached, don't bother trying to write stuff out */
2793                 dcs = BTRFS_DC_WRITTEN;
2794                 spin_unlock(&block_group->lock);
2795                 goto out_put;
2796         }
2797         spin_unlock(&block_group->lock);
2798
2799         num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024);
2800         if (!num_pages)
2801                 num_pages = 1;
2802
2803         /*
2804          * Just to make absolutely sure we have enough space, we're going to
2805          * preallocate 12 pages worth of space for each block group.  In
2806          * practice we ought to use at most 8, but we need extra space so we can
2807          * add our header and have a terminator between the extents and the
2808          * bitmaps.
2809          */
2810         num_pages *= 16;
2811         num_pages *= PAGE_CACHE_SIZE;
2812
2813         ret = btrfs_check_data_free_space(inode, num_pages);
2814         if (ret)
2815                 goto out_put;
2816
2817         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2818                                               num_pages, num_pages,
2819                                               &alloc_hint);
2820         if (!ret)
2821                 dcs = BTRFS_DC_SETUP;
2822         btrfs_free_reserved_data_space(inode, num_pages);
2823
2824 out_put:
2825         iput(inode);
2826 out_free:
2827         btrfs_release_path(path);
2828 out:
2829         spin_lock(&block_group->lock);
2830         if (!ret && dcs == BTRFS_DC_SETUP)
2831                 block_group->cache_generation = trans->transid;
2832         block_group->disk_cache_state = dcs;
2833         spin_unlock(&block_group->lock);
2834
2835         return ret;
2836 }
2837
2838 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
2839                                    struct btrfs_root *root)
2840 {
2841         struct btrfs_block_group_cache *cache;
2842         int err = 0;
2843         struct btrfs_path *path;
2844         u64 last = 0;
2845
2846         path = btrfs_alloc_path();
2847         if (!path)
2848                 return -ENOMEM;
2849
2850 again:
2851         while (1) {
2852                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2853                 while (cache) {
2854                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2855                                 break;
2856                         cache = next_block_group(root, cache);
2857                 }
2858                 if (!cache) {
2859                         if (last == 0)
2860                                 break;
2861                         last = 0;
2862                         continue;
2863                 }
2864                 err = cache_save_setup(cache, trans, path);
2865                 last = cache->key.objectid + cache->key.offset;
2866                 btrfs_put_block_group(cache);
2867         }
2868
2869         while (1) {
2870                 if (last == 0) {
2871                         err = btrfs_run_delayed_refs(trans, root,
2872                                                      (unsigned long)-1);
2873                         BUG_ON(err);
2874                 }
2875
2876                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2877                 while (cache) {
2878                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
2879                                 btrfs_put_block_group(cache);
2880                                 goto again;
2881                         }
2882
2883                         if (cache->dirty)
2884                                 break;
2885                         cache = next_block_group(root, cache);
2886                 }
2887                 if (!cache) {
2888                         if (last == 0)
2889                                 break;
2890                         last = 0;
2891                         continue;
2892                 }
2893
2894                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
2895                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
2896                 cache->dirty = 0;
2897                 last = cache->key.objectid + cache->key.offset;
2898
2899                 err = write_one_cache_group(trans, root, path, cache);
2900                 BUG_ON(err);
2901                 btrfs_put_block_group(cache);
2902         }
2903
2904         while (1) {
2905                 /*
2906                  * I don't think this is needed since we're just marking our
2907                  * preallocated extent as written, but just in case it can't
2908                  * hurt.
2909                  */
2910                 if (last == 0) {
2911                         err = btrfs_run_delayed_refs(trans, root,
2912                                                      (unsigned long)-1);
2913                         BUG_ON(err);
2914                 }
2915
2916                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
2917                 while (cache) {
2918                         /*
2919                          * Really this shouldn't happen, but it could if we
2920                          * couldn't write the entire preallocated extent and
2921                          * splitting the extent resulted in a new block.
2922                          */
2923                         if (cache->dirty) {
2924                                 btrfs_put_block_group(cache);
2925                                 goto again;
2926                         }
2927                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2928                                 break;
2929                         cache = next_block_group(root, cache);
2930                 }
2931                 if (!cache) {
2932                         if (last == 0)
2933                                 break;
2934                         last = 0;
2935                         continue;
2936                 }
2937
2938                 btrfs_write_out_cache(root, trans, cache, path);
2939
2940                 /*
2941                  * If we didn't have an error then the cache state is still
2942                  * NEED_WRITE, so we can set it to WRITTEN.
2943                  */
2944                 if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
2945                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
2946                 last = cache->key.objectid + cache->key.offset;
2947                 btrfs_put_block_group(cache);
2948         }
2949
2950         btrfs_free_path(path);
2951         return 0;
2952 }
2953
2954 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
2955 {
2956         struct btrfs_block_group_cache *block_group;
2957         int readonly = 0;
2958
2959         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
2960         if (!block_group || block_group->ro)
2961                 readonly = 1;
2962         if (block_group)
2963                 btrfs_put_block_group(block_group);
2964         return readonly;
2965 }
2966
2967 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
2968                              u64 total_bytes, u64 bytes_used,
2969                              struct btrfs_space_info **space_info)
2970 {
2971         struct btrfs_space_info *found;
2972         int i;
2973         int factor;
2974
2975         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
2976                      BTRFS_BLOCK_GROUP_RAID10))
2977                 factor = 2;
2978         else
2979                 factor = 1;
2980
2981         found = __find_space_info(info, flags);
2982         if (found) {
2983                 spin_lock(&found->lock);
2984                 found->total_bytes += total_bytes;
2985                 found->disk_total += total_bytes * factor;
2986                 found->bytes_used += bytes_used;
2987                 found->disk_used += bytes_used * factor;
2988                 found->full = 0;
2989                 spin_unlock(&found->lock);
2990                 *space_info = found;
2991                 return 0;
2992         }
2993         found = kzalloc(sizeof(*found), GFP_NOFS);
2994         if (!found)
2995                 return -ENOMEM;
2996
2997         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
2998                 INIT_LIST_HEAD(&found->block_groups[i]);
2999         init_rwsem(&found->groups_sem);
3000         spin_lock_init(&found->lock);
3001         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3002         found->total_bytes = total_bytes;
3003         found->disk_total = total_bytes * factor;
3004         found->bytes_used = bytes_used;
3005         found->disk_used = bytes_used * factor;
3006         found->bytes_pinned = 0;
3007         found->bytes_reserved = 0;
3008         found->bytes_readonly = 0;
3009         found->bytes_may_use = 0;
3010         found->full = 0;
3011         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3012         found->chunk_alloc = 0;
3013         found->flush = 0;
3014         init_waitqueue_head(&found->wait);
3015         *space_info = found;
3016         list_add_rcu(&found->list, &info->space_info);
3017         return 0;
3018 }
3019
3020 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3021 {
3022         u64 extra_flags = flags & BTRFS_BLOCK_GROUP_PROFILE_MASK;
3023
3024         /* chunk -> extended profile */
3025         if (extra_flags == 0)
3026                 extra_flags = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3027
3028         if (flags & BTRFS_BLOCK_GROUP_DATA)
3029                 fs_info->avail_data_alloc_bits |= extra_flags;
3030         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3031                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3032         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3033                 fs_info->avail_system_alloc_bits |= extra_flags;
3034 }
3035
3036 /*
3037  * @flags: available profiles in extended format (see ctree.h)
3038  *
3039  * Returns reduced profile in chunk format.  If profile changing is in
3040  * progress (either running or paused) picks the target profile (if it's
3041  * already available), otherwise falls back to plain reducing.
3042  */
3043 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3044 {
3045         /*
3046          * we add in the count of missing devices because we want
3047          * to make sure that any RAID levels on a degraded FS
3048          * continue to be honored.
3049          */
3050         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3051                 root->fs_info->fs_devices->missing_devices;
3052
3053         /* pick restriper's target profile if it's available */
3054         spin_lock(&root->fs_info->balance_lock);
3055         if (root->fs_info->balance_ctl) {
3056                 struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
3057                 u64 tgt = 0;
3058
3059                 if ((flags & BTRFS_BLOCK_GROUP_DATA) &&
3060                     (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3061                     (flags & bctl->data.target)) {
3062                         tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3063                 } else if ((flags & BTRFS_BLOCK_GROUP_SYSTEM) &&
3064                            (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3065                            (flags & bctl->sys.target)) {
3066                         tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3067                 } else if ((flags & BTRFS_BLOCK_GROUP_METADATA) &&
3068                            (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3069                            (flags & bctl->meta.target)) {
3070                         tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3071                 }
3072
3073                 if (tgt) {
3074                         spin_unlock(&root->fs_info->balance_lock);
3075                         flags = tgt;
3076                         goto out;
3077                 }
3078         }
3079         spin_unlock(&root->fs_info->balance_lock);
3080
3081         if (num_devices == 1)
3082                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
3083         if (num_devices < 4)
3084                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3085
3086         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
3087             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3088                       BTRFS_BLOCK_GROUP_RAID10))) {
3089                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
3090         }
3091
3092         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
3093             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
3094                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
3095         }
3096
3097         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
3098             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
3099              (flags & BTRFS_BLOCK_GROUP_RAID10) |
3100              (flags & BTRFS_BLOCK_GROUP_DUP))) {
3101                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
3102         }
3103
3104 out:
3105         /* extended -> chunk profile */
3106         flags &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3107         return flags;
3108 }
3109
3110 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3111 {
3112         if (flags & BTRFS_BLOCK_GROUP_DATA)
3113                 flags |= root->fs_info->avail_data_alloc_bits;
3114         else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3115                 flags |= root->fs_info->avail_system_alloc_bits;
3116         else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3117                 flags |= root->fs_info->avail_metadata_alloc_bits;
3118
3119         return btrfs_reduce_alloc_profile(root, flags);
3120 }
3121
3122 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3123 {
3124         u64 flags;
3125
3126         if (data)
3127                 flags = BTRFS_BLOCK_GROUP_DATA;
3128         else if (root == root->fs_info->chunk_root)
3129                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3130         else
3131                 flags = BTRFS_BLOCK_GROUP_METADATA;
3132
3133         return get_alloc_profile(root, flags);
3134 }
3135
3136 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
3137 {
3138         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
3139                                                        BTRFS_BLOCK_GROUP_DATA);
3140 }
3141
3142 /*
3143  * This will check the space that the inode allocates from to make sure we have
3144  * enough space for bytes.
3145  */
3146 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3147 {
3148         struct btrfs_space_info *data_sinfo;
3149         struct btrfs_root *root = BTRFS_I(inode)->root;
3150         u64 used;
3151         int ret = 0, committed = 0, alloc_chunk = 1;
3152
3153         /* make sure bytes are sectorsize aligned */
3154         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3155
3156         if (root == root->fs_info->tree_root ||
3157             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID) {
3158                 alloc_chunk = 0;
3159                 committed = 1;
3160         }
3161
3162         data_sinfo = BTRFS_I(inode)->space_info;
3163         if (!data_sinfo)
3164                 goto alloc;
3165
3166 again:
3167         /* make sure we have enough space to handle the data first */
3168         spin_lock(&data_sinfo->lock);
3169         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3170                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3171                 data_sinfo->bytes_may_use;
3172
3173         if (used + bytes > data_sinfo->total_bytes) {
3174                 struct btrfs_trans_handle *trans;
3175
3176                 /*
3177                  * if we don't have enough free bytes in this space then we need
3178                  * to alloc a new chunk.
3179                  */
3180                 if (!data_sinfo->full && alloc_chunk) {
3181                         u64 alloc_target;
3182
3183                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3184                         spin_unlock(&data_sinfo->lock);
3185 alloc:
3186                         alloc_target = btrfs_get_alloc_profile(root, 1);
3187                         trans = btrfs_join_transaction(root);
3188                         if (IS_ERR(trans))
3189                                 return PTR_ERR(trans);
3190
3191                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3192                                              bytes + 2 * 1024 * 1024,
3193                                              alloc_target,
3194                                              CHUNK_ALLOC_NO_FORCE);
3195                         btrfs_end_transaction(trans, root);
3196                         if (ret < 0) {
3197                                 if (ret != -ENOSPC)
3198                                         return ret;
3199                                 else
3200                                         goto commit_trans;
3201                         }
3202
3203                         if (!data_sinfo) {
3204                                 btrfs_set_inode_space_info(root, inode);
3205                                 data_sinfo = BTRFS_I(inode)->space_info;
3206                         }
3207                         goto again;
3208                 }
3209
3210                 /*
3211                  * If we have less pinned bytes than we want to allocate then
3212                  * don't bother committing the transaction, it won't help us.
3213                  */
3214                 if (data_sinfo->bytes_pinned < bytes)
3215                         committed = 1;
3216                 spin_unlock(&data_sinfo->lock);
3217
3218                 /* commit the current transaction and try again */
3219 commit_trans:
3220                 if (!committed &&
3221                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3222                         committed = 1;
3223                         trans = btrfs_join_transaction(root);
3224                         if (IS_ERR(trans))
3225                                 return PTR_ERR(trans);
3226                         ret = btrfs_commit_transaction(trans, root);
3227                         if (ret)
3228                                 return ret;
3229                         goto again;
3230                 }
3231
3232                 return -ENOSPC;
3233         }
3234         data_sinfo->bytes_may_use += bytes;
3235         spin_unlock(&data_sinfo->lock);
3236
3237         return 0;
3238 }
3239
3240 /*
3241  * Called if we need to clear a data reservation for this inode.
3242  */
3243 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3244 {
3245         struct btrfs_root *root = BTRFS_I(inode)->root;
3246         struct btrfs_space_info *data_sinfo;
3247
3248         /* make sure bytes are sectorsize aligned */
3249         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
3250
3251         data_sinfo = BTRFS_I(inode)->space_info;
3252         spin_lock(&data_sinfo->lock);
3253         data_sinfo->bytes_may_use -= bytes;
3254         spin_unlock(&data_sinfo->lock);
3255 }
3256
3257 static void force_metadata_allocation(struct btrfs_fs_info *info)
3258 {
3259         struct list_head *head = &info->space_info;
3260         struct btrfs_space_info *found;
3261
3262         rcu_read_lock();
3263         list_for_each_entry_rcu(found, head, list) {
3264                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3265                         found->force_alloc = CHUNK_ALLOC_FORCE;
3266         }
3267         rcu_read_unlock();
3268 }
3269
3270 static int should_alloc_chunk(struct btrfs_root *root,
3271                               struct btrfs_space_info *sinfo, u64 alloc_bytes,
3272                               int force)
3273 {
3274         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3275         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3276         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3277         u64 thresh;
3278
3279         if (force == CHUNK_ALLOC_FORCE)
3280                 return 1;
3281
3282         /*
3283          * We need to take into account the global rsv because for all intents
3284          * and purposes it's used space.  Don't worry about locking the
3285          * global_rsv, it doesn't change except when the transaction commits.
3286          */
3287         num_allocated += global_rsv->size;
3288
3289         /*
3290          * in limited mode, we want to have some free space up to
3291          * about 1% of the FS size.
3292          */
3293         if (force == CHUNK_ALLOC_LIMITED) {
3294                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3295                 thresh = max_t(u64, 64 * 1024 * 1024,
3296                                div_factor_fine(thresh, 1));
3297
3298                 if (num_bytes - num_allocated < thresh)
3299                         return 1;
3300         }
3301         thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3302
3303         /* 256MB or 2% of the FS */
3304         thresh = max_t(u64, 256 * 1024 * 1024, div_factor_fine(thresh, 2));
3305
3306         if (num_bytes > thresh && sinfo->bytes_used < div_factor(num_bytes, 8))
3307                 return 0;
3308         return 1;
3309 }
3310
3311 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3312                           struct btrfs_root *extent_root, u64 alloc_bytes,
3313                           u64 flags, int force)
3314 {
3315         struct btrfs_space_info *space_info;
3316         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3317         int wait_for_alloc = 0;
3318         int ret = 0;
3319
3320         BUG_ON(!profile_is_valid(flags, 0));
3321
3322         space_info = __find_space_info(extent_root->fs_info, flags);
3323         if (!space_info) {
3324                 ret = update_space_info(extent_root->fs_info, flags,
3325                                         0, 0, &space_info);
3326                 BUG_ON(ret);
3327         }
3328         BUG_ON(!space_info);
3329
3330 again:
3331         spin_lock(&space_info->lock);
3332         if (space_info->force_alloc)
3333                 force = space_info->force_alloc;
3334         if (space_info->full) {
3335                 spin_unlock(&space_info->lock);
3336                 return 0;
3337         }
3338
3339         if (!should_alloc_chunk(extent_root, space_info, alloc_bytes, force)) {
3340                 spin_unlock(&space_info->lock);
3341                 return 0;
3342         } else if (space_info->chunk_alloc) {
3343                 wait_for_alloc = 1;
3344         } else {
3345                 space_info->chunk_alloc = 1;
3346         }
3347
3348         spin_unlock(&space_info->lock);
3349
3350         mutex_lock(&fs_info->chunk_mutex);
3351
3352         /*
3353          * The chunk_mutex is held throughout the entirety of a chunk
3354          * allocation, so once we've acquired the chunk_mutex we know that the
3355          * other guy is done and we need to recheck and see if we should
3356          * allocate.
3357          */
3358         if (wait_for_alloc) {
3359                 mutex_unlock(&fs_info->chunk_mutex);
3360                 wait_for_alloc = 0;
3361                 goto again;
3362         }
3363
3364         /*
3365          * If we have mixed data/metadata chunks we want to make sure we keep
3366          * allocating mixed chunks instead of individual chunks.
3367          */
3368         if (btrfs_mixed_space_info(space_info))
3369                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3370
3371         /*
3372          * if we're doing a data chunk, go ahead and make sure that
3373          * we keep a reasonable number of metadata chunks allocated in the
3374          * FS as well.
3375          */
3376         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3377                 fs_info->data_chunk_allocations++;
3378                 if (!(fs_info->data_chunk_allocations %
3379                       fs_info->metadata_ratio))
3380                         force_metadata_allocation(fs_info);
3381         }
3382
3383         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3384         if (ret < 0 && ret != -ENOSPC)
3385                 goto out;
3386
3387         spin_lock(&space_info->lock);
3388         if (ret)
3389                 space_info->full = 1;
3390         else
3391                 ret = 1;
3392
3393         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3394         space_info->chunk_alloc = 0;
3395         spin_unlock(&space_info->lock);
3396 out:
3397         mutex_unlock(&extent_root->fs_info->chunk_mutex);
3398         return ret;
3399 }
3400
3401 /*
3402  * shrink metadata reservation for delalloc
3403  */
3404 static int shrink_delalloc(struct btrfs_root *root, u64 to_reclaim,
3405                            bool wait_ordered)
3406 {
3407         struct btrfs_block_rsv *block_rsv;
3408         struct btrfs_space_info *space_info;
3409         struct btrfs_trans_handle *trans;
3410         u64 reserved;
3411         u64 max_reclaim;
3412         u64 reclaimed = 0;
3413         long time_left;
3414         unsigned long nr_pages = (2 * 1024 * 1024) >> PAGE_CACHE_SHIFT;
3415         int loops = 0;
3416         unsigned long progress;
3417
3418         trans = (struct btrfs_trans_handle *)current->journal_info;
3419         block_rsv = &root->fs_info->delalloc_block_rsv;
3420         space_info = block_rsv->space_info;
3421
3422         smp_mb();
3423         reserved = space_info->bytes_may_use;
3424         progress = space_info->reservation_progress;
3425
3426         if (reserved == 0)
3427                 return 0;
3428
3429         smp_mb();
3430         if (root->fs_info->delalloc_bytes == 0) {
3431                 if (trans)
3432                         return 0;
3433                 btrfs_wait_ordered_extents(root, 0, 0);
3434                 return 0;
3435         }
3436
3437         max_reclaim = min(reserved, to_reclaim);
3438         nr_pages = max_t(unsigned long, nr_pages,
3439                          max_reclaim >> PAGE_CACHE_SHIFT);
3440         while (loops < 1024) {
3441                 /* have the flusher threads jump in and do some IO */
3442                 smp_mb();
3443                 nr_pages = min_t(unsigned long, nr_pages,
3444                        root->fs_info->delalloc_bytes >> PAGE_CACHE_SHIFT);
3445                 writeback_inodes_sb_nr_if_idle(root->fs_info->sb, nr_pages,
3446                                                 WB_REASON_FS_FREE_SPACE);
3447
3448                 spin_lock(&space_info->lock);
3449                 if (reserved > space_info->bytes_may_use)
3450                         reclaimed += reserved - space_info->bytes_may_use;
3451                 reserved = space_info->bytes_may_use;
3452                 spin_unlock(&space_info->lock);
3453
3454                 loops++;
3455
3456                 if (reserved == 0 || reclaimed >= max_reclaim)
3457                         break;
3458
3459                 if (trans && trans->transaction->blocked)
3460                         return -EAGAIN;
3461
3462                 if (wait_ordered && !trans) {
3463                         btrfs_wait_ordered_extents(root, 0, 0);
3464                 } else {
3465                         time_left = schedule_timeout_interruptible(1);
3466
3467                         /* We were interrupted, exit */
3468                         if (time_left)
3469                                 break;
3470                 }
3471
3472                 /* we've kicked the IO a few times, if anything has been freed,
3473                  * exit.  There is no sense in looping here for a long time
3474                  * when we really need to commit the transaction, or there are
3475                  * just too many writers without enough free space
3476                  */
3477
3478                 if (loops > 3) {
3479                         smp_mb();
3480                         if (progress != space_info->reservation_progress)
3481                                 break;
3482                 }
3483
3484         }
3485
3486         return reclaimed >= to_reclaim;
3487 }
3488
3489 /**
3490  * maybe_commit_transaction - possibly commit the transaction if its ok to
3491  * @root - the root we're allocating for
3492  * @bytes - the number of bytes we want to reserve
3493  * @force - force the commit
3494  *
3495  * This will check to make sure that committing the transaction will actually
3496  * get us somewhere and then commit the transaction if it does.  Otherwise it
3497  * will return -ENOSPC.
3498  */
3499 static int may_commit_transaction(struct btrfs_root *root,
3500                                   struct btrfs_space_info *space_info,
3501                                   u64 bytes, int force)
3502 {
3503         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
3504         struct btrfs_trans_handle *trans;
3505
3506         trans = (struct btrfs_trans_handle *)current->journal_info;
3507         if (trans)
3508                 return -EAGAIN;
3509
3510         if (force)
3511                 goto commit;
3512
3513         /* See if there is enough pinned space to make this reservation */
3514         spin_lock(&space_info->lock);
3515         if (space_info->bytes_pinned >= bytes) {
3516                 spin_unlock(&space_info->lock);
3517                 goto commit;
3518         }
3519         spin_unlock(&space_info->lock);
3520
3521         /*
3522          * See if there is some space in the delayed insertion reservation for
3523          * this reservation.
3524          */
3525         if (space_info != delayed_rsv->space_info)
3526                 return -ENOSPC;
3527
3528         spin_lock(&delayed_rsv->lock);
3529         if (delayed_rsv->size < bytes) {
3530                 spin_unlock(&delayed_rsv->lock);
3531                 return -ENOSPC;
3532         }
3533         spin_unlock(&delayed_rsv->lock);
3534
3535 commit:
3536         trans = btrfs_join_transaction(root);
3537         if (IS_ERR(trans))
3538                 return -ENOSPC;
3539
3540         return btrfs_commit_transaction(trans, root);
3541 }
3542
3543 /**
3544  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
3545  * @root - the root we're allocating for
3546  * @block_rsv - the block_rsv we're allocating for
3547  * @orig_bytes - the number of bytes we want
3548  * @flush - wether or not we can flush to make our reservation
3549  *
3550  * This will reserve orgi_bytes number of bytes from the space info associated
3551  * with the block_rsv.  If there is not enough space it will make an attempt to
3552  * flush out space to make room.  It will do this by flushing delalloc if
3553  * possible or committing the transaction.  If flush is 0 then no attempts to
3554  * regain reservations will be made and this will fail if there is not enough
3555  * space already.
3556  */
3557 static int reserve_metadata_bytes(struct btrfs_root *root,
3558                                   struct btrfs_block_rsv *block_rsv,
3559                                   u64 orig_bytes, int flush)
3560 {
3561         struct btrfs_space_info *space_info = block_rsv->space_info;
3562         u64 used;
3563         u64 num_bytes = orig_bytes;
3564         int retries = 0;
3565         int ret = 0;
3566         bool committed = false;
3567         bool flushing = false;
3568         bool wait_ordered = false;
3569
3570 again:
3571         ret = 0;
3572         spin_lock(&space_info->lock);
3573         /*
3574          * We only want to wait if somebody other than us is flushing and we are
3575          * actually alloed to flush.
3576          */
3577         while (flush && !flushing && space_info->flush) {
3578                 spin_unlock(&space_info->lock);
3579                 /*
3580                  * If we have a trans handle we can't wait because the flusher
3581                  * may have to commit the transaction, which would mean we would
3582                  * deadlock since we are waiting for the flusher to finish, but
3583                  * hold the current transaction open.
3584                  */
3585                 if (current->journal_info)
3586                         return -EAGAIN;
3587                 ret = wait_event_interruptible(space_info->wait,
3588                                                !space_info->flush);
3589                 /* Must have been interrupted, return */
3590                 if (ret)
3591                         return -EINTR;
3592
3593                 spin_lock(&space_info->lock);
3594         }
3595
3596         ret = -ENOSPC;
3597         used = space_info->bytes_used + space_info->bytes_reserved +
3598                 space_info->bytes_pinned + space_info->bytes_readonly +
3599                 space_info->bytes_may_use;
3600
3601         /*
3602          * The idea here is that we've not already over-reserved the block group
3603          * then we can go ahead and save our reservation first and then start
3604          * flushing if we need to.  Otherwise if we've already overcommitted
3605          * lets start flushing stuff first and then come back and try to make
3606          * our reservation.
3607          */
3608         if (used <= space_info->total_bytes) {
3609                 if (used + orig_bytes <= space_info->total_bytes) {
3610                         space_info->bytes_may_use += orig_bytes;
3611                         ret = 0;
3612                 } else {
3613                         /*
3614                          * Ok set num_bytes to orig_bytes since we aren't
3615                          * overocmmitted, this way we only try and reclaim what
3616                          * we need.
3617                          */
3618                         num_bytes = orig_bytes;
3619                 }
3620         } else {
3621                 /*
3622                  * Ok we're over committed, set num_bytes to the overcommitted
3623                  * amount plus the amount of bytes that we need for this
3624                  * reservation.
3625                  */
3626                 wait_ordered = true;
3627                 num_bytes = used - space_info->total_bytes +
3628                         (orig_bytes * (retries + 1));
3629         }
3630
3631         if (ret) {
3632                 u64 profile = btrfs_get_alloc_profile(root, 0);
3633                 u64 avail;
3634
3635                 /*
3636                  * If we have a lot of space that's pinned, don't bother doing
3637                  * the overcommit dance yet and just commit the transaction.
3638                  */
3639                 avail = (space_info->total_bytes - space_info->bytes_used) * 8;
3640                 do_div(avail, 10);
3641                 if (space_info->bytes_pinned >= avail && flush && !committed) {
3642                         space_info->flush = 1;
3643                         flushing = true;
3644                         spin_unlock(&space_info->lock);
3645                         ret = may_commit_transaction(root, space_info,
3646                                                      orig_bytes, 1);
3647                         if (ret)
3648                                 goto out;
3649                         committed = true;
3650                         goto again;
3651                 }
3652
3653                 spin_lock(&root->fs_info->free_chunk_lock);
3654                 avail = root->fs_info->free_chunk_space;
3655
3656                 /*
3657                  * If we have dup, raid1 or raid10 then only half of the free
3658                  * space is actually useable.
3659                  */
3660                 if (profile & (BTRFS_BLOCK_GROUP_DUP |
3661                                BTRFS_BLOCK_GROUP_RAID1 |
3662                                BTRFS_BLOCK_GROUP_RAID10))
3663                         avail >>= 1;
3664
3665                 /*
3666                  * If we aren't flushing don't let us overcommit too much, say
3667                  * 1/8th of the space.  If we can flush, let it overcommit up to
3668                  * 1/2 of the space.
3669                  */
3670                 if (flush)
3671                         avail >>= 3;
3672                 else
3673                         avail >>= 1;
3674                  spin_unlock(&root->fs_info->free_chunk_lock);
3675
3676                 if (used + num_bytes < space_info->total_bytes + avail) {
3677                         space_info->bytes_may_use += orig_bytes;
3678                         ret = 0;
3679                 } else {
3680                         wait_ordered = true;
3681                 }
3682         }
3683
3684         /*
3685          * Couldn't make our reservation, save our place so while we're trying
3686          * to reclaim space we can actually use it instead of somebody else
3687          * stealing it from us.
3688          */
3689         if (ret && flush) {
3690                 flushing = true;
3691                 space_info->flush = 1;
3692         }
3693
3694         spin_unlock(&space_info->lock);
3695
3696         if (!ret || !flush)
3697                 goto out;
3698
3699         /*
3700          * We do synchronous shrinking since we don't actually unreserve
3701          * metadata until after the IO is completed.
3702          */
3703         ret = shrink_delalloc(root, num_bytes, wait_ordered);
3704         if (ret < 0)
3705                 goto out;
3706
3707         ret = 0;
3708
3709         /*
3710          * So if we were overcommitted it's possible that somebody else flushed
3711          * out enough space and we simply didn't have enough space to reclaim,
3712          * so go back around and try again.
3713          */
3714         if (retries < 2) {
3715                 wait_ordered = true;
3716                 retries++;
3717                 goto again;
3718         }
3719
3720         ret = -ENOSPC;
3721         if (committed)
3722                 goto out;
3723
3724         ret = may_commit_transaction(root, space_info, orig_bytes, 0);
3725         if (!ret) {
3726                 committed = true;
3727                 goto again;
3728         }
3729
3730 out:
3731         if (flushing) {
3732                 spin_lock(&space_info->lock);
3733                 space_info->flush = 0;
3734                 wake_up_all(&space_info->wait);
3735                 spin_unlock(&space_info->lock);
3736         }
3737         return ret;
3738 }
3739
3740 static struct btrfs_block_rsv *get_block_rsv(struct btrfs_trans_handle *trans,
3741                                              struct btrfs_root *root)
3742 {
3743         struct btrfs_block_rsv *block_rsv = NULL;
3744
3745         if (root->ref_cows || root == root->fs_info->csum_root)
3746                 block_rsv = trans->block_rsv;
3747
3748         if (!block_rsv)
3749                 block_rsv = root->block_rsv;
3750
3751         if (!block_rsv)
3752                 block_rsv = &root->fs_info->empty_block_rsv;
3753
3754         return block_rsv;
3755 }
3756
3757 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
3758                                u64 num_bytes)
3759 {
3760         int ret = -ENOSPC;
3761         spin_lock(&block_rsv->lock);
3762         if (block_rsv->reserved >= num_bytes) {
3763                 block_rsv->reserved -= num_bytes;
3764                 if (block_rsv->reserved < block_rsv->size)
3765                         block_rsv->full = 0;
3766                 ret = 0;
3767         }
3768         spin_unlock(&block_rsv->lock);
3769         return ret;
3770 }
3771
3772 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
3773                                 u64 num_bytes, int update_size)
3774 {
3775         spin_lock(&block_rsv->lock);
3776         block_rsv->reserved += num_bytes;
3777         if (update_size)
3778                 block_rsv->size += num_bytes;
3779         else if (block_rsv->reserved >= block_rsv->size)
3780                 block_rsv->full = 1;
3781         spin_unlock(&block_rsv->lock);
3782 }
3783
3784 static void block_rsv_release_bytes(struct btrfs_block_rsv *block_rsv,
3785                                     struct btrfs_block_rsv *dest, u64 num_bytes)
3786 {
3787         struct btrfs_space_info *space_info = block_rsv->space_info;
3788
3789         spin_lock(&block_rsv->lock);
3790         if (num_bytes == (u64)-1)
3791                 num_bytes = block_rsv->size;
3792         block_rsv->size -= num_bytes;
3793         if (block_rsv->reserved >= block_rsv->size) {
3794                 num_bytes = block_rsv->reserved - block_rsv->size;
3795                 block_rsv->reserved = block_rsv->size;
3796                 block_rsv->full = 1;
3797         } else {
3798                 num_bytes = 0;
3799         }
3800         spin_unlock(&block_rsv->lock);
3801
3802         if (num_bytes > 0) {
3803                 if (dest) {
3804                         spin_lock(&dest->lock);
3805                         if (!dest->full) {
3806                                 u64 bytes_to_add;
3807
3808                                 bytes_to_add = dest->size - dest->reserved;
3809                                 bytes_to_add = min(num_bytes, bytes_to_add);
3810                                 dest->reserved += bytes_to_add;
3811                                 if (dest->reserved >= dest->size)
3812                                         dest->full = 1;
3813                                 num_bytes -= bytes_to_add;
3814                         }
3815                         spin_unlock(&dest->lock);
3816                 }
3817                 if (num_bytes) {
3818                         spin_lock(&space_info->lock);
3819                         space_info->bytes_may_use -= num_bytes;
3820                         space_info->reservation_progress++;
3821                         spin_unlock(&space_info->lock);
3822                 }
3823         }
3824 }
3825
3826 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
3827                                    struct btrfs_block_rsv *dst, u64 num_bytes)
3828 {
3829         int ret;
3830
3831         ret = block_rsv_use_bytes(src, num_bytes);
3832         if (ret)
3833                 return ret;
3834
3835         block_rsv_add_bytes(dst, num_bytes, 1);
3836         return 0;
3837 }
3838
3839 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv)
3840 {
3841         memset(rsv, 0, sizeof(*rsv));
3842         spin_lock_init(&rsv->lock);
3843 }
3844
3845 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root)
3846 {
3847         struct btrfs_block_rsv *block_rsv;
3848         struct btrfs_fs_info *fs_info = root->fs_info;
3849
3850         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
3851         if (!block_rsv)
3852                 return NULL;
3853
3854         btrfs_init_block_rsv(block_rsv);
3855         block_rsv->space_info = __find_space_info(fs_info,
3856                                                   BTRFS_BLOCK_GROUP_METADATA);
3857         return block_rsv;
3858 }
3859
3860 void btrfs_free_block_rsv(struct btrfs_root *root,
3861                           struct btrfs_block_rsv *rsv)
3862 {
3863         btrfs_block_rsv_release(root, rsv, (u64)-1);
3864         kfree(rsv);
3865 }
3866
3867 static inline int __block_rsv_add(struct btrfs_root *root,
3868                                   struct btrfs_block_rsv *block_rsv,
3869                                   u64 num_bytes, int flush)
3870 {
3871         int ret;
3872
3873         if (num_bytes == 0)
3874                 return 0;
3875
3876         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
3877         if (!ret) {
3878                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
3879                 return 0;
3880         }
3881
3882         return ret;
3883 }
3884
3885 int btrfs_block_rsv_add(struct btrfs_root *root,
3886                         struct btrfs_block_rsv *block_rsv,
3887                         u64 num_bytes)
3888 {
3889         return __block_rsv_add(root, block_rsv, num_bytes, 1);
3890 }
3891
3892 int btrfs_block_rsv_add_noflush(struct btrfs_root *root,
3893                                 struct btrfs_block_rsv *block_rsv,
3894                                 u64 num_bytes)
3895 {
3896         return __block_rsv_add(root, block_rsv, num_bytes, 0);
3897 }
3898
3899 int btrfs_block_rsv_check(struct btrfs_root *root,
3900                           struct btrfs_block_rsv *block_rsv, int min_factor)
3901 {
3902         u64 num_bytes = 0;
3903         int ret = -ENOSPC;
3904
3905         if (!block_rsv)
3906                 return 0;
3907
3908         spin_lock(&block_rsv->lock);
3909         num_bytes = div_factor(block_rsv->size, min_factor);
3910         if (block_rsv->reserved >= num_bytes)
3911                 ret = 0;
3912         spin_unlock(&block_rsv->lock);
3913
3914         return ret;
3915 }
3916
3917 static inline int __btrfs_block_rsv_refill(struct btrfs_root *root,
3918                                            struct btrfs_block_rsv *block_rsv,
3919                                            u64 min_reserved, int flush)
3920 {
3921         u64 num_bytes = 0;
3922         int ret = -ENOSPC;
3923
3924         if (!block_rsv)
3925                 return 0;
3926
3927         spin_lock(&block_rsv->lock);
3928         num_bytes = min_reserved;
3929         if (block_rsv->reserved >= num_bytes)
3930                 ret = 0;
3931         else
3932                 num_bytes -= block_rsv->reserved;
3933         spin_unlock(&block_rsv->lock);
3934
3935         if (!ret)
3936                 return 0;
3937
3938         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
3939         if (!ret) {
3940                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
3941                 return 0;
3942         }
3943
3944         return ret;
3945 }
3946
3947 int btrfs_block_rsv_refill(struct btrfs_root *root,
3948                            struct btrfs_block_rsv *block_rsv,
3949                            u64 min_reserved)
3950 {
3951         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 1);
3952 }
3953
3954 int btrfs_block_rsv_refill_noflush(struct btrfs_root *root,
3955                                    struct btrfs_block_rsv *block_rsv,
3956                                    u64 min_reserved)
3957 {
3958         return __btrfs_block_rsv_refill(root, block_rsv, min_reserved, 0);
3959 }
3960
3961 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
3962                             struct btrfs_block_rsv *dst_rsv,
3963                             u64 num_bytes)
3964 {
3965         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
3966 }
3967
3968 void btrfs_block_rsv_release(struct btrfs_root *root,
3969                              struct btrfs_block_rsv *block_rsv,
3970                              u64 num_bytes)
3971 {
3972         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3973         if (global_rsv->full || global_rsv == block_rsv ||
3974             block_rsv->space_info != global_rsv->space_info)
3975                 global_rsv = NULL;
3976         block_rsv_release_bytes(block_rsv, global_rsv, num_bytes);
3977 }
3978
3979 /*
3980  * helper to calculate size of global block reservation.
3981  * the desired value is sum of space used by extent tree,
3982  * checksum tree and root tree
3983  */
3984 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
3985 {
3986         struct btrfs_space_info *sinfo;
3987         u64 num_bytes;
3988         u64 meta_used;
3989         u64 data_used;
3990         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
3991
3992         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
3993         spin_lock(&sinfo->lock);
3994         data_used = sinfo->bytes_used;
3995         spin_unlock(&sinfo->lock);
3996
3997         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
3998         spin_lock(&sinfo->lock);
3999         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4000                 data_used = 0;
4001         meta_used = sinfo->bytes_used;
4002         spin_unlock(&sinfo->lock);
4003
4004         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4005                     csum_size * 2;
4006         num_bytes += div64_u64(data_used + meta_used, 50);
4007
4008         if (num_bytes * 3 > meta_used)
4009                 num_bytes = div64_u64(meta_used, 3);
4010
4011         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4012 }
4013
4014 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4015 {
4016         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4017         struct btrfs_space_info *sinfo = block_rsv->space_info;
4018         u64 num_bytes;
4019
4020         num_bytes = calc_global_metadata_size(fs_info);
4021
4022         spin_lock(&block_rsv->lock);
4023         spin_lock(&sinfo->lock);
4024
4025         block_rsv->size = num_bytes;
4026
4027         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4028                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4029                     sinfo->bytes_may_use;
4030
4031         if (sinfo->total_bytes > num_bytes) {
4032                 num_bytes = sinfo->total_bytes - num_bytes;
4033                 block_rsv->reserved += num_bytes;
4034                 sinfo->bytes_may_use += num_bytes;
4035         }
4036
4037         if (block_rsv->reserved >= block_rsv->size) {
4038                 num_bytes = block_rsv->reserved - block_rsv->size;
4039                 sinfo->bytes_may_use -= num_bytes;
4040                 sinfo->reservation_progress++;
4041                 block_rsv->reserved = block_rsv->size;
4042                 block_rsv->full = 1;
4043         }
4044
4045         spin_unlock(&sinfo->lock);
4046         spin_unlock(&block_rsv->lock);
4047 }
4048
4049 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4050 {
4051         struct btrfs_space_info *space_info;
4052
4053         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4054         fs_info->chunk_block_rsv.space_info = space_info;
4055
4056         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4057         fs_info->global_block_rsv.space_info = space_info;
4058         fs_info->delalloc_block_rsv.space_info = space_info;
4059         fs_info->trans_block_rsv.space_info = space_info;
4060         fs_info->empty_block_rsv.space_info = space_info;
4061         fs_info->delayed_block_rsv.space_info = space_info;
4062
4063         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4064         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4065         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4066         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4067         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4068
4069         update_global_block_rsv(fs_info);
4070 }
4071
4072 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4073 {
4074         block_rsv_release_bytes(&fs_info->global_block_rsv, NULL, (u64)-1);
4075         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4076         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4077         WARN_ON(fs_info->trans_block_rsv.size > 0);
4078         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4079         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4080         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4081         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4082         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4083 }
4084
4085 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4086                                   struct btrfs_root *root)
4087 {
4088         if (!trans->bytes_reserved)
4089                 return;
4090
4091         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4092         trans->bytes_reserved = 0;
4093 }
4094
4095 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4096                                   struct inode *inode)
4097 {
4098         struct btrfs_root *root = BTRFS_I(inode)->root;
4099         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4100         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4101
4102         /*
4103          * We need to hold space in order to delete our orphan item once we've
4104          * added it, so this takes the reservation so we can release it later
4105          * when we are truly done with the orphan item.
4106          */
4107         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4108         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4109 }
4110
4111 void btrfs_orphan_release_metadata(struct inode *inode)
4112 {
4113         struct btrfs_root *root = BTRFS_I(inode)->root;
4114         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4115         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4116 }
4117
4118 int btrfs_snap_reserve_metadata(struct btrfs_trans_handle *trans,
4119                                 struct btrfs_pending_snapshot *pending)
4120 {
4121         struct btrfs_root *root = pending->root;
4122         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4123         struct btrfs_block_rsv *dst_rsv = &pending->block_rsv;
4124         /*
4125          * two for root back/forward refs, two for directory entries
4126          * and one for root of the snapshot.
4127          */
4128         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 5);
4129         dst_rsv->space_info = src_rsv->space_info;
4130         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4131 }
4132
4133 /**
4134  * drop_outstanding_extent - drop an outstanding extent
4135  * @inode: the inode we're dropping the extent for
4136  *
4137  * This is called when we are freeing up an outstanding extent, either called
4138  * after an error or after an extent is written.  This will return the number of
4139  * reserved extents that need to be freed.  This must be called with
4140  * BTRFS_I(inode)->lock held.
4141  */
4142 static unsigned drop_outstanding_extent(struct inode *inode)
4143 {
4144         unsigned drop_inode_space = 0;
4145         unsigned dropped_extents = 0;
4146
4147         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4148         BTRFS_I(inode)->outstanding_extents--;
4149
4150         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4151             BTRFS_I(inode)->delalloc_meta_reserved) {
4152                 drop_inode_space = 1;
4153                 BTRFS_I(inode)->delalloc_meta_reserved = 0;
4154         }
4155
4156         /*
4157          * If we have more or the same amount of outsanding extents than we have
4158          * reserved then we need to leave the reserved extents count alone.
4159          */
4160         if (BTRFS_I(inode)->outstanding_extents >=
4161             BTRFS_I(inode)->reserved_extents)
4162                 return drop_inode_space;
4163
4164         dropped_extents = BTRFS_I(inode)->reserved_extents -
4165                 BTRFS_I(inode)->outstanding_extents;
4166         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4167         return dropped_extents + drop_inode_space;
4168 }
4169
4170 /**
4171  * calc_csum_metadata_size - return the amount of metada space that must be
4172  *      reserved/free'd for the given bytes.
4173  * @inode: the inode we're manipulating
4174  * @num_bytes: the number of bytes in question
4175  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4176  *
4177  * This adjusts the number of csum_bytes in the inode and then returns the
4178  * correct amount of metadata that must either be reserved or freed.  We
4179  * calculate how many checksums we can fit into one leaf and then divide the
4180  * number of bytes that will need to be checksumed by this value to figure out
4181  * how many checksums will be required.  If we are adding bytes then the number
4182  * may go up and we will return the number of additional bytes that must be
4183  * reserved.  If it is going down we will return the number of bytes that must
4184  * be freed.
4185  *
4186  * This must be called with BTRFS_I(inode)->lock held.
4187  */
4188 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4189                                    int reserve)
4190 {
4191         struct btrfs_root *root = BTRFS_I(inode)->root;
4192         u64 csum_size;
4193         int num_csums_per_leaf;
4194         int num_csums;
4195         int old_csums;
4196
4197         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4198             BTRFS_I(inode)->csum_bytes == 0)
4199                 return 0;
4200
4201         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4202         if (reserve)
4203                 BTRFS_I(inode)->csum_bytes += num_bytes;
4204         else
4205                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4206         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4207         num_csums_per_leaf = (int)div64_u64(csum_size,
4208                                             sizeof(struct btrfs_csum_item) +
4209                                             sizeof(struct btrfs_disk_key));
4210         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4211         num_csums = num_csums + num_csums_per_leaf - 1;
4212         num_csums = num_csums / num_csums_per_leaf;
4213
4214         old_csums = old_csums + num_csums_per_leaf - 1;
4215         old_csums = old_csums / num_csums_per_leaf;
4216
4217         /* No change, no need to reserve more */
4218         if (old_csums == num_csums)
4219                 return 0;
4220
4221         if (reserve)
4222                 return btrfs_calc_trans_metadata_size(root,
4223                                                       num_csums - old_csums);
4224
4225         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4226 }
4227
4228 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4229 {
4230         struct btrfs_root *root = BTRFS_I(inode)->root;
4231         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4232         u64 to_reserve = 0;
4233         u64 csum_bytes;
4234         unsigned nr_extents = 0;
4235         int extra_reserve = 0;
4236         int flush = 1;
4237         int ret;
4238
4239         /* Need to be holding the i_mutex here if we aren't free space cache */
4240         if (btrfs_is_free_space_inode(root, inode))
4241                 flush = 0;
4242         else
4243                 WARN_ON(!mutex_is_locked(&inode->i_mutex));
4244
4245         if (flush && btrfs_transaction_in_commit(root->fs_info))
4246                 schedule_timeout(1);
4247
4248         num_bytes = ALIGN(num_bytes, root->sectorsize);
4249
4250         spin_lock(&BTRFS_I(inode)->lock);
4251         BTRFS_I(inode)->outstanding_extents++;
4252
4253         if (BTRFS_I(inode)->outstanding_extents >
4254             BTRFS_I(inode)->reserved_extents)
4255                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4256                         BTRFS_I(inode)->reserved_extents;
4257
4258         /*
4259          * Add an item to reserve for updating the inode when we complete the
4260          * delalloc io.
4261          */
4262         if (!BTRFS_I(inode)->delalloc_meta_reserved) {
4263                 nr_extents++;
4264                 extra_reserve = 1;
4265         }
4266
4267         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
4268         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
4269         csum_bytes = BTRFS_I(inode)->csum_bytes;
4270         spin_unlock(&BTRFS_I(inode)->lock);
4271
4272         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
4273         if (ret) {
4274                 u64 to_free = 0;
4275                 unsigned dropped;
4276
4277                 spin_lock(&BTRFS_I(inode)->lock);
4278                 dropped = drop_outstanding_extent(inode);
4279                 /*
4280                  * If the inodes csum_bytes is the same as the original
4281                  * csum_bytes then we know we haven't raced with any free()ers
4282                  * so we can just reduce our inodes csum bytes and carry on.
4283                  * Otherwise we have to do the normal free thing to account for
4284                  * the case that the free side didn't free up its reserve
4285                  * because of this outstanding reservation.
4286                  */
4287                 if (BTRFS_I(inode)->csum_bytes == csum_bytes)
4288                         calc_csum_metadata_size(inode, num_bytes, 0);
4289                 else
4290                         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4291                 spin_unlock(&BTRFS_I(inode)->lock);
4292                 if (dropped)
4293                         to_free += btrfs_calc_trans_metadata_size(root, dropped);
4294
4295                 if (to_free)
4296                         btrfs_block_rsv_release(root, block_rsv, to_free);
4297                 return ret;
4298         }
4299
4300         spin_lock(&BTRFS_I(inode)->lock);
4301         if (extra_reserve) {
4302                 BTRFS_I(inode)->delalloc_meta_reserved = 1;
4303                 nr_extents--;
4304         }
4305         BTRFS_I(inode)->reserved_extents += nr_extents;
4306         spin_unlock(&BTRFS_I(inode)->lock);
4307
4308         block_rsv_add_bytes(block_rsv, to_reserve, 1);
4309
4310         return 0;
4311 }
4312
4313 /**
4314  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
4315  * @inode: the inode to release the reservation for
4316  * @num_bytes: the number of bytes we're releasing
4317  *
4318  * This will release the metadata reservation for an inode.  This can be called
4319  * once we complete IO for a given set of bytes to release their metadata
4320  * reservations.
4321  */
4322 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
4323 {
4324         struct btrfs_root *root = BTRFS_I(inode)->root;
4325         u64 to_free = 0;
4326         unsigned dropped;
4327
4328         num_bytes = ALIGN(num_bytes, root->sectorsize);
4329         spin_lock(&BTRFS_I(inode)->lock);
4330         dropped = drop_outstanding_extent(inode);
4331
4332         to_free = calc_csum_metadata_size(inode, num_bytes, 0);
4333         spin_unlock(&BTRFS_I(inode)->lock);
4334         if (dropped > 0)
4335                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
4336
4337         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
4338                                 to_free);
4339 }
4340
4341 /**
4342  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
4343  * @inode: inode we're writing to
4344  * @num_bytes: the number of bytes we want to allocate
4345  *
4346  * This will do the following things
4347  *
4348  * o reserve space in the data space info for num_bytes
4349  * o reserve space in the metadata space info based on number of outstanding
4350  *   extents and how much csums will be needed
4351  * o add to the inodes ->delalloc_bytes
4352  * o add it to the fs_info's delalloc inodes list.
4353  *
4354  * This will return 0 for success and -ENOSPC if there is no space left.
4355  */
4356 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
4357 {
4358         int ret;
4359
4360         ret = btrfs_check_data_free_space(inode, num_bytes);
4361         if (ret)
4362                 return ret;
4363
4364         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
4365         if (ret) {
4366                 btrfs_free_reserved_data_space(inode, num_bytes);
4367                 return ret;
4368         }
4369
4370         return 0;
4371 }
4372
4373 /**
4374  * btrfs_delalloc_release_space - release data and metadata space for delalloc
4375  * @inode: inode we're releasing space for
4376  * @num_bytes: the number of bytes we want to free up
4377  *
4378  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
4379  * called in the case that we don't need the metadata AND data reservations
4380  * anymore.  So if there is an error or we insert an inline extent.
4381  *
4382  * This function will release the metadata space that was not used and will
4383  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
4384  * list if there are no delalloc bytes left.
4385  */
4386 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
4387 {
4388         btrfs_delalloc_release_metadata(inode, num_bytes);
4389         btrfs_free_reserved_data_space(inode, num_bytes);
4390 }
4391
4392 static int update_block_group(struct btrfs_trans_handle *trans,
4393                               struct btrfs_root *root,
4394                               u64 bytenr, u64 num_bytes, int alloc)
4395 {
4396         struct btrfs_block_group_cache *cache = NULL;
4397         struct btrfs_fs_info *info = root->fs_info;
4398         u64 total = num_bytes;
4399         u64 old_val;
4400         u64 byte_in_group;
4401         int factor;
4402
4403         /* block accounting for super block */
4404         spin_lock(&info->delalloc_lock);
4405         old_val = btrfs_super_bytes_used(info->super_copy);
4406         if (alloc)
4407                 old_val += num_bytes;
4408         else
4409                 old_val -= num_bytes;
4410         btrfs_set_super_bytes_used(info->super_copy, old_val);
4411         spin_unlock(&info->delalloc_lock);
4412
4413         while (total) {
4414                 cache = btrfs_lookup_block_group(info, bytenr);
4415                 if (!cache)
4416                         return -1;
4417                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
4418                                     BTRFS_BLOCK_GROUP_RAID1 |
4419                                     BTRFS_BLOCK_GROUP_RAID10))
4420                         factor = 2;
4421                 else
4422                         factor = 1;
4423                 /*
4424                  * If this block group has free space cache written out, we
4425                  * need to make sure to load it if we are removing space.  This
4426                  * is because we need the unpinning stage to actually add the
4427                  * space back to the block group, otherwise we will leak space.
4428                  */
4429                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
4430                         cache_block_group(cache, trans, NULL, 1);
4431
4432                 byte_in_group = bytenr - cache->key.objectid;
4433                 WARN_ON(byte_in_group > cache->key.offset);
4434
4435                 spin_lock(&cache->space_info->lock);
4436                 spin_lock(&cache->lock);
4437
4438                 if (btrfs_test_opt(root, SPACE_CACHE) &&
4439                     cache->disk_cache_state < BTRFS_DC_CLEAR)
4440                         cache->disk_cache_state = BTRFS_DC_CLEAR;
4441
4442                 cache->dirty = 1;
4443                 old_val = btrfs_block_group_used(&cache->item);
4444                 num_bytes = min(total, cache->key.offset - byte_in_group);
4445                 if (alloc) {
4446                         old_val += num_bytes;
4447                         btrfs_set_block_group_used(&cache->item, old_val);
4448                         cache->reserved -= num_bytes;
4449                         cache->space_info->bytes_reserved -= num_bytes;
4450                         cache->space_info->bytes_used += num_bytes;
4451                         cache->space_info->disk_used += num_bytes * factor;
4452                         spin_unlock(&cache->lock);
4453                         spin_unlock(&cache->space_info->lock);
4454                 } else {
4455                         old_val -= num_bytes;
4456                         btrfs_set_block_group_used(&cache->item, old_val);
4457                         cache->pinned += num_bytes;
4458                         cache->space_info->bytes_pinned += num_bytes;
4459                         cache->space_info->bytes_used -= num_bytes;
4460                         cache->space_info->disk_used -= num_bytes * factor;
4461                         spin_unlock(&cache->lock);
4462                         spin_unlock(&cache->space_info->lock);
4463
4464                         set_extent_dirty(info->pinned_extents,
4465                                          bytenr, bytenr + num_bytes - 1,
4466                                          GFP_NOFS | __GFP_NOFAIL);
4467                 }
4468                 btrfs_put_block_group(cache);
4469                 total -= num_bytes;
4470                 bytenr += num_bytes;
4471         }
4472         return 0;
4473 }
4474
4475 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
4476 {
4477         struct btrfs_block_group_cache *cache;
4478         u64 bytenr;
4479
4480         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
4481         if (!cache)
4482                 return 0;
4483
4484         bytenr = cache->key.objectid;
4485         btrfs_put_block_group(cache);
4486
4487         return bytenr;
4488 }
4489
4490 static int pin_down_extent(struct btrfs_root *root,
4491                            struct btrfs_block_group_cache *cache,
4492                            u64 bytenr, u64 num_bytes, int reserved)
4493 {
4494         spin_lock(&cache->space_info->lock);
4495         spin_lock(&cache->lock);
4496         cache->pinned += num_bytes;
4497         cache->space_info->bytes_pinned += num_bytes;
4498         if (reserved) {
4499                 cache->reserved -= num_bytes;
4500                 cache->space_info->bytes_reserved -= num_bytes;
4501         }
4502         spin_unlock(&cache->lock);
4503         spin_unlock(&cache->space_info->lock);
4504
4505         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
4506                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
4507         return 0;
4508 }
4509
4510 /*
4511  * this function must be called within transaction
4512  */
4513 int btrfs_pin_extent(struct btrfs_root *root,
4514                      u64 bytenr, u64 num_bytes, int reserved)
4515 {
4516         struct btrfs_block_group_cache *cache;
4517
4518         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4519         BUG_ON(!cache);
4520
4521         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
4522
4523         btrfs_put_block_group(cache);
4524         return 0;
4525 }
4526
4527 /*
4528  * this function must be called within transaction
4529  */
4530 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
4531                                     struct btrfs_root *root,
4532                                     u64 bytenr, u64 num_bytes)
4533 {
4534         struct btrfs_block_group_cache *cache;
4535
4536         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
4537         BUG_ON(!cache);
4538
4539         /*
4540          * pull in the free space cache (if any) so that our pin
4541          * removes the free space from the cache.  We have load_only set
4542          * to one because the slow code to read in the free extents does check
4543          * the pinned extents.
4544          */
4545         cache_block_group(cache, trans, root, 1);
4546
4547         pin_down_extent(root, cache, bytenr, num_bytes, 0);
4548
4549         /* remove us from the free space cache (if we're there at all) */
4550         btrfs_remove_free_space(cache, bytenr, num_bytes);
4551         btrfs_put_block_group(cache);
4552         return 0;
4553 }
4554
4555 /**
4556  * btrfs_update_reserved_bytes - update the block_group and space info counters
4557  * @cache:      The cache we are manipulating
4558  * @num_bytes:  The number of bytes in question
4559  * @reserve:    One of the reservation enums
4560  *
4561  * This is called by the allocator when it reserves space, or by somebody who is
4562  * freeing space that was never actually used on disk.  For example if you
4563  * reserve some space for a new leaf in transaction A and before transaction A
4564  * commits you free that leaf, you call this with reserve set to 0 in order to
4565  * clear the reservation.
4566  *
4567  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
4568  * ENOSPC accounting.  For data we handle the reservation through clearing the
4569  * delalloc bits in the io_tree.  We have to do this since we could end up
4570  * allocating less disk space for the amount of data we have reserved in the
4571  * case of compression.
4572  *
4573  * If this is a reservation and the block group has become read only we cannot
4574  * make the reservation and return -EAGAIN, otherwise this function always
4575  * succeeds.
4576  */
4577 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
4578                                        u64 num_bytes, int reserve)
4579 {
4580         struct btrfs_space_info *space_info = cache->space_info;
4581         int ret = 0;
4582         spin_lock(&space_info->lock);
4583         spin_lock(&cache->lock);
4584         if (reserve != RESERVE_FREE) {
4585                 if (cache->ro) {
4586                         ret = -EAGAIN;
4587                 } else {
4588                         cache->reserved += num_bytes;
4589                         space_info->bytes_reserved += num_bytes;
4590                         if (reserve == RESERVE_ALLOC) {
4591                                 BUG_ON(space_info->bytes_may_use < num_bytes);
4592                                 space_info->bytes_may_use -= num_bytes;
4593                         }
4594                 }
4595         } else {
4596                 if (cache->ro)
4597                         space_info->bytes_readonly += num_bytes;
4598                 cache->reserved -= num_bytes;
4599                 space_info->bytes_reserved -= num_bytes;
4600                 space_info->reservation_progress++;
4601         }
4602         spin_unlock(&cache->lock);
4603         spin_unlock(&space_info->lock);
4604         return ret;
4605 }
4606
4607 int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
4608                                 struct btrfs_root *root)
4609 {
4610         struct btrfs_fs_info *fs_info = root->fs_info;
4611         struct btrfs_caching_control *next;
4612         struct btrfs_caching_control *caching_ctl;
4613         struct btrfs_block_group_cache *cache;
4614
4615         down_write(&fs_info->extent_commit_sem);
4616
4617         list_for_each_entry_safe(caching_ctl, next,
4618                                  &fs_info->caching_block_groups, list) {
4619                 cache = caching_ctl->block_group;
4620                 if (block_group_cache_done(cache)) {
4621                         cache->last_byte_to_unpin = (u64)-1;
4622                         list_del_init(&caching_ctl->list);
4623                         put_caching_control(caching_ctl);
4624                 } else {
4625                         cache->last_byte_to_unpin = caching_ctl->progress;
4626                 }
4627         }
4628
4629         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4630                 fs_info->pinned_extents = &fs_info->freed_extents[1];
4631         else
4632                 fs_info->pinned_extents = &fs_info->freed_extents[0];
4633
4634         up_write(&fs_info->extent_commit_sem);
4635
4636         update_global_block_rsv(fs_info);
4637         return 0;
4638 }
4639
4640 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
4641 {
4642         struct btrfs_fs_info *fs_info = root->fs_info;
4643         struct btrfs_block_group_cache *cache = NULL;
4644         u64 len;
4645
4646         while (start <= end) {
4647                 if (!cache ||
4648                     start >= cache->key.objectid + cache->key.offset) {
4649                         if (cache)
4650                                 btrfs_put_block_group(cache);
4651                         cache = btrfs_lookup_block_group(fs_info, start);
4652                         BUG_ON(!cache);
4653                 }
4654
4655                 len = cache->key.objectid + cache->key.offset - start;
4656                 len = min(len, end + 1 - start);
4657
4658                 if (start < cache->last_byte_to_unpin) {
4659                         len = min(len, cache->last_byte_to_unpin - start);
4660                         btrfs_add_free_space(cache, start, len);
4661                 }
4662
4663                 start += len;
4664
4665                 spin_lock(&cache->space_info->lock);
4666                 spin_lock(&cache->lock);
4667                 cache->pinned -= len;
4668                 cache->space_info->bytes_pinned -= len;
4669                 if (cache->ro)
4670                         cache->space_info->bytes_readonly += len;
4671                 spin_unlock(&cache->lock);
4672                 spin_unlock(&cache->space_info->lock);
4673         }
4674
4675         if (cache)
4676                 btrfs_put_block_group(cache);
4677         return 0;
4678 }
4679
4680 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
4681                                struct btrfs_root *root)
4682 {
4683         struct btrfs_fs_info *fs_info = root->fs_info;
4684         struct extent_io_tree *unpin;
4685         u64 start;
4686         u64 end;
4687         int ret;
4688
4689         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
4690                 unpin = &fs_info->freed_extents[1];
4691         else
4692                 unpin = &fs_info->freed_extents[0];
4693
4694         while (1) {
4695                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4696                                             EXTENT_DIRTY);
4697                 if (ret)
4698                         break;
4699
4700                 if (btrfs_test_opt(root, DISCARD))
4701                         ret = btrfs_discard_extent(root, start,
4702                                                    end + 1 - start, NULL);
4703
4704                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4705                 unpin_extent_range(root, start, end);
4706                 cond_resched();
4707         }
4708
4709         return 0;
4710 }
4711
4712 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
4713                                 struct btrfs_root *root,
4714                                 u64 bytenr, u64 num_bytes, u64 parent,
4715                                 u64 root_objectid, u64 owner_objectid,
4716                                 u64 owner_offset, int refs_to_drop,
4717                                 struct btrfs_delayed_extent_op *extent_op)
4718 {
4719         struct btrfs_key key;
4720         struct btrfs_path *path;
4721         struct btrfs_fs_info *info = root->fs_info;
4722         struct btrfs_root *extent_root = info->extent_root;
4723         struct extent_buffer *leaf;
4724         struct btrfs_extent_item *ei;
4725         struct btrfs_extent_inline_ref *iref;
4726         int ret;
4727         int is_data;
4728         int extent_slot = 0;
4729         int found_extent = 0;
4730         int num_to_del = 1;
4731         u32 item_size;
4732         u64 refs;
4733
4734         path = btrfs_alloc_path();
4735         if (!path)
4736                 return -ENOMEM;
4737
4738         path->reada = 1;
4739         path->leave_spinning = 1;
4740
4741         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
4742         BUG_ON(!is_data && refs_to_drop != 1);
4743
4744         ret = lookup_extent_backref(trans, extent_root, path, &iref,
4745                                     bytenr, num_bytes, parent,
4746                                     root_objectid, owner_objectid,
4747                                     owner_offset);
4748         if (ret == 0) {
4749                 extent_slot = path->slots[0];
4750                 while (extent_slot >= 0) {
4751                         btrfs_item_key_to_cpu(path->nodes[0], &key,
4752                                               extent_slot);
4753                         if (key.objectid != bytenr)
4754                                 break;
4755                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
4756                             key.offset == num_bytes) {
4757                                 found_extent = 1;
4758                                 break;
4759                         }
4760                         if (path->slots[0] - extent_slot > 5)
4761                                 break;
4762                         extent_slot--;
4763                 }
4764 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4765                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
4766                 if (found_extent && item_size < sizeof(*ei))
4767                         found_extent = 0;
4768 #endif
4769                 if (!found_extent) {
4770                         BUG_ON(iref);
4771                         ret = remove_extent_backref(trans, extent_root, path,
4772                                                     NULL, refs_to_drop,
4773                                                     is_data);
4774                         BUG_ON(ret);
4775                         btrfs_release_path(path);
4776                         path->leave_spinning = 1;
4777
4778                         key.objectid = bytenr;
4779                         key.type = BTRFS_EXTENT_ITEM_KEY;
4780                         key.offset = num_bytes;
4781
4782                         ret = btrfs_search_slot(trans, extent_root,
4783                                                 &key, path, -1, 1);
4784                         if (ret) {
4785                                 printk(KERN_ERR "umm, got %d back from search"
4786                                        ", was looking for %llu\n", ret,
4787                                        (unsigned long long)bytenr);
4788                                 if (ret > 0)
4789                                         btrfs_print_leaf(extent_root,
4790                                                          path->nodes[0]);
4791                         }
4792                         BUG_ON(ret);
4793                         extent_slot = path->slots[0];
4794                 }
4795         } else {
4796                 btrfs_print_leaf(extent_root, path->nodes[0]);
4797                 WARN_ON(1);
4798                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
4799                        "parent %llu root %llu  owner %llu offset %llu\n",
4800                        (unsigned long long)bytenr,
4801                        (unsigned long long)parent,
4802                        (unsigned long long)root_objectid,
4803                        (unsigned long long)owner_objectid,
4804                        (unsigned long long)owner_offset);
4805         }
4806
4807         leaf = path->nodes[0];
4808         item_size = btrfs_item_size_nr(leaf, extent_slot);
4809 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4810         if (item_size < sizeof(*ei)) {
4811                 BUG_ON(found_extent || extent_slot != path->slots[0]);
4812                 ret = convert_extent_item_v0(trans, extent_root, path,
4813                                              owner_objectid, 0);
4814                 BUG_ON(ret < 0);
4815
4816                 btrfs_release_path(path);
4817                 path->leave_spinning = 1;
4818
4819                 key.objectid = bytenr;
4820                 key.type = BTRFS_EXTENT_ITEM_KEY;
4821                 key.offset = num_bytes;
4822
4823                 ret = btrfs_search_slot(trans, extent_root, &key, path,
4824                                         -1, 1);
4825                 if (ret) {
4826                         printk(KERN_ERR "umm, got %d back from search"
4827                                ", was looking for %llu\n", ret,
4828                                (unsigned long long)bytenr);
4829                         btrfs_print_leaf(extent_root, path->nodes[0]);
4830                 }
4831                 BUG_ON(ret);
4832                 extent_slot = path->slots[0];
4833                 leaf = path->nodes[0];
4834                 item_size = btrfs_item_size_nr(leaf, extent_slot);
4835         }
4836 #endif
4837         BUG_ON(item_size < sizeof(*ei));
4838         ei = btrfs_item_ptr(leaf, extent_slot,
4839                             struct btrfs_extent_item);
4840         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4841                 struct btrfs_tree_block_info *bi;
4842                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
4843                 bi = (struct btrfs_tree_block_info *)(ei + 1);
4844                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
4845         }
4846
4847         refs = btrfs_extent_refs(leaf, ei);
4848         BUG_ON(refs < refs_to_drop);
4849         refs -= refs_to_drop;
4850
4851         if (refs > 0) {
4852                 if (extent_op)
4853                         __run_delayed_extent_op(extent_op, leaf, ei);
4854                 /*
4855                  * In the case of inline back ref, reference count will
4856                  * be updated by remove_extent_backref
4857                  */
4858                 if (iref) {
4859                         BUG_ON(!found_extent);
4860                 } else {
4861                         btrfs_set_extent_refs(leaf, ei, refs);
4862                         btrfs_mark_buffer_dirty(leaf);
4863                 }
4864                 if (found_extent) {
4865                         ret = remove_extent_backref(trans, extent_root, path,
4866                                                     iref, refs_to_drop,
4867                                                     is_data);
4868                         BUG_ON(ret);
4869                 }
4870         } else {
4871                 if (found_extent) {
4872                         BUG_ON(is_data && refs_to_drop !=
4873                                extent_data_ref_count(root, path, iref));
4874                         if (iref) {
4875                                 BUG_ON(path->slots[0] != extent_slot);
4876                         } else {
4877                                 BUG_ON(path->slots[0] != extent_slot + 1);
4878                                 path->slots[0] = extent_slot;
4879                                 num_to_del = 2;
4880                         }
4881                 }
4882
4883                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
4884                                       num_to_del);
4885                 BUG_ON(ret);
4886                 btrfs_release_path(path);
4887
4888                 if (is_data) {
4889                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
4890                         BUG_ON(ret);
4891                 } else {
4892                         invalidate_mapping_pages(info->btree_inode->i_mapping,
4893                              bytenr >> PAGE_CACHE_SHIFT,
4894                              (bytenr + num_bytes - 1) >> PAGE_CACHE_SHIFT);
4895                 }
4896
4897                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
4898                 BUG_ON(ret);
4899         }
4900         btrfs_free_path(path);
4901         return ret;
4902 }
4903
4904 /*
4905  * when we free an block, it is possible (and likely) that we free the last
4906  * delayed ref for that extent as well.  This searches the delayed ref tree for
4907  * a given extent, and if there are no other delayed refs to be processed, it
4908  * removes it from the tree.
4909  */
4910 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
4911                                       struct btrfs_root *root, u64 bytenr)
4912 {
4913         struct btrfs_delayed_ref_head *head;
4914         struct btrfs_delayed_ref_root *delayed_refs;
4915         struct btrfs_delayed_ref_node *ref;
4916         struct rb_node *node;
4917         int ret = 0;
4918
4919         delayed_refs = &trans->transaction->delayed_refs;
4920         spin_lock(&delayed_refs->lock);
4921         head = btrfs_find_delayed_ref_head(trans, bytenr);
4922         if (!head)
4923                 goto out;
4924
4925         node = rb_prev(&head->node.rb_node);
4926         if (!node)
4927                 goto out;
4928
4929         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
4930
4931         /* there are still entries for this ref, we can't drop it */
4932         if (ref->bytenr == bytenr)
4933                 goto out;
4934
4935         if (head->extent_op) {
4936                 if (!head->must_insert_reserved)
4937                         goto out;
4938                 kfree(head->extent_op);
4939                 head->extent_op = NULL;
4940         }
4941
4942         /*
4943          * waiting for the lock here would deadlock.  If someone else has it
4944          * locked they are already in the process of dropping it anyway
4945          */
4946         if (!mutex_trylock(&head->mutex))
4947                 goto out;
4948
4949         /*
4950          * at this point we have a head with no other entries.  Go
4951          * ahead and process it.
4952          */
4953         head->node.in_tree = 0;
4954         rb_erase(&head->node.rb_node, &delayed_refs->root);
4955
4956         delayed_refs->num_entries--;
4957
4958         /*
4959          * we don't take a ref on the node because we're removing it from the
4960          * tree, so we just steal the ref the tree was holding.
4961          */
4962         delayed_refs->num_heads--;
4963         if (list_empty(&head->cluster))
4964                 delayed_refs->num_heads_ready--;
4965
4966         list_del_init(&head->cluster);
4967         spin_unlock(&delayed_refs->lock);
4968
4969         BUG_ON(head->extent_op);
4970         if (head->must_insert_reserved)
4971                 ret = 1;
4972
4973         mutex_unlock(&head->mutex);
4974         btrfs_put_delayed_ref(&head->node);
4975         return ret;
4976 out:
4977         spin_unlock(&delayed_refs->lock);
4978         return 0;
4979 }
4980
4981 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
4982                            struct btrfs_root *root,
4983                            struct extent_buffer *buf,
4984                            u64 parent, int last_ref)
4985 {
4986         struct btrfs_block_group_cache *cache = NULL;
4987         int ret;
4988
4989         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
4990                 ret = btrfs_add_delayed_tree_ref(trans, buf->start, buf->len,
4991                                                 parent, root->root_key.objectid,
4992                                                 btrfs_header_level(buf),
4993                                                 BTRFS_DROP_DELAYED_REF, NULL);
4994                 BUG_ON(ret);
4995         }
4996
4997         if (!last_ref)
4998                 return;
4999
5000         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
5001
5002         if (btrfs_header_generation(buf) == trans->transid) {
5003                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5004                         ret = check_ref_cleanup(trans, root, buf->start);
5005                         if (!ret)
5006                                 goto out;
5007                 }
5008
5009                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
5010                         pin_down_extent(root, cache, buf->start, buf->len, 1);
5011                         goto out;
5012                 }
5013
5014                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
5015
5016                 btrfs_add_free_space(cache, buf->start, buf->len);
5017                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
5018         }
5019 out:
5020         /*
5021          * Deleting the buffer, clear the corrupt flag since it doesn't matter
5022          * anymore.
5023          */
5024         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
5025         btrfs_put_block_group(cache);
5026 }
5027
5028 int btrfs_free_extent(struct btrfs_trans_handle *trans,
5029                       struct btrfs_root *root,
5030                       u64 bytenr, u64 num_bytes, u64 parent,
5031                       u64 root_objectid, u64 owner, u64 offset)
5032 {
5033         int ret;
5034
5035         /*
5036          * tree log blocks never actually go into the extent allocation
5037          * tree, just update pinning info and exit early.
5038          */
5039         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
5040                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
5041                 /* unlocks the pinned mutex */
5042                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
5043                 ret = 0;
5044         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5045                 ret = btrfs_add_delayed_tree_ref(trans, bytenr, num_bytes,
5046                                         parent, root_objectid, (int)owner,
5047                                         BTRFS_DROP_DELAYED_REF, NULL);
5048                 BUG_ON(ret);
5049         } else {
5050                 ret = btrfs_add_delayed_data_ref(trans, bytenr, num_bytes,
5051                                         parent, root_objectid, owner,
5052                                         offset, BTRFS_DROP_DELAYED_REF, NULL);
5053                 BUG_ON(ret);
5054         }
5055         return ret;
5056 }
5057
5058 static u64 stripe_align(struct btrfs_root *root, u64 val)
5059 {
5060         u64 mask = ((u64)root->stripesize - 1);
5061         u64 ret = (val + mask) & ~mask;
5062         return ret;
5063 }
5064
5065 /*
5066  * when we wait for progress in the block group caching, its because
5067  * our allocation attempt failed at least once.  So, we must sleep
5068  * and let some progress happen before we try again.
5069  *
5070  * This function will sleep at least once waiting for new free space to
5071  * show up, and then it will check the block group free space numbers
5072  * for our min num_bytes.  Another option is to have it go ahead
5073  * and look in the rbtree for a free extent of a given size, but this
5074  * is a good start.
5075  */
5076 static noinline int
5077 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
5078                                 u64 num_bytes)
5079 {
5080         struct btrfs_caching_control *caching_ctl;
5081         DEFINE_WAIT(wait);
5082
5083         caching_ctl = get_caching_control(cache);
5084         if (!caching_ctl)
5085                 return 0;
5086
5087         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
5088                    (cache->free_space_ctl->free_space >= num_bytes));
5089
5090         put_caching_control(caching_ctl);
5091         return 0;
5092 }
5093
5094 static noinline int
5095 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
5096 {
5097         struct btrfs_caching_control *caching_ctl;
5098         DEFINE_WAIT(wait);
5099
5100         caching_ctl = get_caching_control(cache);
5101         if (!caching_ctl)
5102                 return 0;
5103
5104         wait_event(caching_ctl->wait, block_group_cache_done(cache));
5105
5106         put_caching_control(caching_ctl);
5107         return 0;
5108 }
5109
5110 static int get_block_group_index(struct btrfs_block_group_cache *cache)
5111 {
5112         int index;
5113         if (cache->flags & BTRFS_BLOCK_GROUP_RAID10)
5114                 index = 0;
5115         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID1)
5116                 index = 1;
5117         else if (cache->flags & BTRFS_BLOCK_GROUP_DUP)
5118                 index = 2;
5119         else if (cache->flags & BTRFS_BLOCK_GROUP_RAID0)
5120                 index = 3;
5121         else
5122                 index = 4;
5123         return index;
5124 }
5125
5126 enum btrfs_loop_type {
5127         LOOP_FIND_IDEAL = 0,
5128         LOOP_CACHING_NOWAIT = 1,
5129         LOOP_CACHING_WAIT = 2,
5130         LOOP_ALLOC_CHUNK = 3,
5131         LOOP_NO_EMPTY_SIZE = 4,
5132 };
5133
5134 /*
5135  * walks the btree of allocated extents and find a hole of a given size.
5136  * The key ins is changed to record the hole:
5137  * ins->objectid == block start
5138  * ins->flags = BTRFS_EXTENT_ITEM_KEY
5139  * ins->offset == number of blocks
5140  * Any available blocks before search_start are skipped.
5141  */
5142 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
5143                                      struct btrfs_root *orig_root,
5144                                      u64 num_bytes, u64 empty_size,
5145                                      u64 search_start, u64 search_end,
5146                                      u64 hint_byte, struct btrfs_key *ins,
5147                                      u64 data)
5148 {
5149         int ret = 0;
5150         struct btrfs_root *root = orig_root->fs_info->extent_root;
5151         struct btrfs_free_cluster *last_ptr = NULL;
5152         struct btrfs_block_group_cache *block_group = NULL;
5153         struct btrfs_block_group_cache *used_block_group;
5154         int empty_cluster = 2 * 1024 * 1024;
5155         int allowed_chunk_alloc = 0;
5156         int done_chunk_alloc = 0;
5157         struct btrfs_space_info *space_info;
5158         int loop = 0;
5159         int index = 0;
5160         int alloc_type = (data & BTRFS_BLOCK_GROUP_DATA) ?
5161                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
5162         bool found_uncached_bg = false;
5163         bool failed_cluster_refill = false;
5164         bool failed_alloc = false;
5165         bool use_cluster = true;
5166         bool have_caching_bg = false;
5167         u64 ideal_cache_percent = 0;
5168         u64 ideal_cache_offset = 0;
5169
5170         WARN_ON(num_bytes < root->sectorsize);
5171         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
5172         ins->objectid = 0;
5173         ins->offset = 0;
5174
5175         space_info = __find_space_info(root->fs_info, data);
5176         if (!space_info) {
5177                 printk(KERN_ERR "No space info for %llu\n", data);
5178                 return -ENOSPC;
5179         }
5180
5181         /*
5182          * If the space info is for both data and metadata it means we have a
5183          * small filesystem and we can't use the clustering stuff.
5184          */
5185         if (btrfs_mixed_space_info(space_info))
5186                 use_cluster = false;
5187
5188         if (orig_root->ref_cows || empty_size)
5189                 allowed_chunk_alloc = 1;
5190
5191         if (data & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
5192                 last_ptr = &root->fs_info->meta_alloc_cluster;
5193                 if (!btrfs_test_opt(root, SSD))
5194                         empty_cluster = 64 * 1024;
5195         }
5196
5197         if ((data & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
5198             btrfs_test_opt(root, SSD)) {
5199                 last_ptr = &root->fs_info->data_alloc_cluster;
5200         }
5201
5202         if (last_ptr) {
5203                 spin_lock(&last_ptr->lock);
5204                 if (last_ptr->block_group)
5205                         hint_byte = last_ptr->window_start;
5206                 spin_unlock(&last_ptr->lock);
5207         }
5208
5209         search_start = max(search_start, first_logical_byte(root, 0));
5210         search_start = max(search_start, hint_byte);
5211
5212         if (!last_ptr)
5213                 empty_cluster = 0;
5214
5215         if (search_start == hint_byte) {
5216 ideal_cache:
5217                 block_group = btrfs_lookup_block_group(root->fs_info,
5218                                                        search_start);
5219                 used_block_group = block_group;
5220                 /*
5221                  * we don't want to use the block group if it doesn't match our
5222                  * allocation bits, or if its not cached.
5223                  *
5224                  * However if we are re-searching with an ideal block group
5225                  * picked out then we don't care that the block group is cached.
5226                  */
5227                 if (block_group && block_group_bits(block_group, data) &&
5228                     (block_group->cached != BTRFS_CACHE_NO ||
5229                      search_start == ideal_cache_offset)) {
5230                         down_read(&space_info->groups_sem);
5231                         if (list_empty(&block_group->list) ||
5232                             block_group->ro) {
5233                                 /*
5234                                  * someone is removing this block group,
5235                                  * we can't jump into the have_block_group
5236                                  * target because our list pointers are not
5237                                  * valid
5238                                  */
5239                                 btrfs_put_block_group(block_group);
5240                                 up_read(&space_info->groups_sem);
5241                         } else {
5242                                 index = get_block_group_index(block_group);
5243                                 goto have_block_group;
5244                         }
5245                 } else if (block_group) {
5246                         btrfs_put_block_group(block_group);
5247                 }
5248         }
5249 search:
5250         have_caching_bg = false;
5251         down_read(&space_info->groups_sem);
5252         list_for_each_entry(block_group, &space_info->block_groups[index],
5253                             list) {
5254                 u64 offset;
5255                 int cached;
5256
5257                 used_block_group = block_group;
5258                 btrfs_get_block_group(block_group);
5259                 search_start = block_group->key.objectid;
5260
5261                 /*
5262                  * this can happen if we end up cycling through all the
5263                  * raid types, but we want to make sure we only allocate
5264                  * for the proper type.
5265                  */
5266                 if (!block_group_bits(block_group, data)) {
5267                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
5268                                 BTRFS_BLOCK_GROUP_RAID1 |
5269                                 BTRFS_BLOCK_GROUP_RAID10;
5270
5271                         /*
5272                          * if they asked for extra copies and this block group
5273                          * doesn't provide them, bail.  This does allow us to
5274                          * fill raid0 from raid1.
5275                          */
5276                         if ((data & extra) && !(block_group->flags & extra))
5277                                 goto loop;
5278                 }
5279
5280 have_block_group:
5281                 cached = block_group_cache_done(block_group);
5282                 if (unlikely(!cached)) {
5283                         u64 free_percent;
5284
5285                         found_uncached_bg = true;
5286                         ret = cache_block_group(block_group, trans,
5287                                                 orig_root, 1);
5288                         if (block_group->cached == BTRFS_CACHE_FINISHED)
5289                                 goto alloc;
5290
5291                         free_percent = btrfs_block_group_used(&block_group->item);
5292                         free_percent *= 100;
5293                         free_percent = div64_u64(free_percent,
5294                                                  block_group->key.offset);
5295                         free_percent = 100 - free_percent;
5296                         if (free_percent > ideal_cache_percent &&
5297                             likely(!block_group->ro)) {
5298                                 ideal_cache_offset = block_group->key.objectid;
5299                                 ideal_cache_percent = free_percent;
5300                         }
5301
5302                         /*
5303                          * The caching workers are limited to 2 threads, so we
5304                          * can queue as much work as we care to.
5305                          */
5306                         if (loop > LOOP_FIND_IDEAL) {
5307                                 ret = cache_block_group(block_group, trans,
5308                                                         orig_root, 0);
5309                                 BUG_ON(ret);
5310                         }
5311
5312                         /*
5313                          * If loop is set for cached only, try the next block
5314                          * group.
5315                          */
5316                         if (loop == LOOP_FIND_IDEAL)
5317                                 goto loop;
5318                 }
5319
5320 alloc:
5321                 if (unlikely(block_group->ro))
5322                         goto loop;
5323
5324                 /*
5325                  * Ok we want to try and use the cluster allocator, so
5326                  * lets look there
5327                  */
5328                 if (last_ptr) {
5329                         /*
5330                          * the refill lock keeps out other
5331                          * people trying to start a new cluster
5332                          */
5333                         spin_lock(&last_ptr->refill_lock);
5334                         used_block_group = last_ptr->block_group;
5335                         if (used_block_group != block_group &&
5336                             (!used_block_group ||
5337                              used_block_group->ro ||
5338                              !block_group_bits(used_block_group, data))) {
5339                                 used_block_group = block_group;
5340                                 goto refill_cluster;
5341                         }
5342
5343                         if (used_block_group != block_group)
5344                                 btrfs_get_block_group(used_block_group);
5345
5346                         offset = btrfs_alloc_from_cluster(used_block_group,
5347                           last_ptr, num_bytes, used_block_group->key.objectid);
5348                         if (offset) {
5349                                 /* we have a block, we're done */
5350                                 spin_unlock(&last_ptr->refill_lock);
5351                                 goto checks;
5352                         }
5353
5354                         WARN_ON(last_ptr->block_group != used_block_group);
5355                         if (used_block_group != block_group) {
5356                                 btrfs_put_block_group(used_block_group);
5357                                 used_block_group = block_group;
5358                         }
5359 refill_cluster:
5360                         BUG_ON(used_block_group != block_group);
5361                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
5362                          * set up a new clusters, so lets just skip it
5363                          * and let the allocator find whatever block
5364                          * it can find.  If we reach this point, we
5365                          * will have tried the cluster allocator
5366                          * plenty of times and not have found
5367                          * anything, so we are likely way too
5368                          * fragmented for the clustering stuff to find
5369                          * anything.
5370                          *
5371                          * However, if the cluster is taken from the
5372                          * current block group, release the cluster
5373                          * first, so that we stand a better chance of
5374                          * succeeding in the unclustered
5375                          * allocation.  */
5376                         if (loop >= LOOP_NO_EMPTY_SIZE &&
5377                             last_ptr->block_group != block_group) {
5378                                 spin_unlock(&last_ptr->refill_lock);
5379                                 goto unclustered_alloc;
5380                         }
5381
5382                         /*
5383                          * this cluster didn't work out, free it and
5384                          * start over
5385                          */
5386                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5387
5388                         if (loop >= LOOP_NO_EMPTY_SIZE) {
5389                                 spin_unlock(&last_ptr->refill_lock);
5390                                 goto unclustered_alloc;
5391                         }
5392
5393                         /* allocate a cluster in this block group */
5394                         ret = btrfs_find_space_cluster(trans, root,
5395                                                block_group, last_ptr,
5396                                                search_start, num_bytes,
5397                                                empty_cluster + empty_size);
5398                         if (ret == 0) {
5399                                 /*
5400                                  * now pull our allocation out of this
5401                                  * cluster
5402                                  */
5403                                 offset = btrfs_alloc_from_cluster(block_group,
5404                                                   last_ptr, num_bytes,
5405                                                   search_start);
5406                                 if (offset) {
5407                                         /* we found one, proceed */
5408                                         spin_unlock(&last_ptr->refill_lock);
5409                                         goto checks;
5410                                 }
5411                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
5412                                    && !failed_cluster_refill) {
5413                                 spin_unlock(&last_ptr->refill_lock);
5414
5415                                 failed_cluster_refill = true;
5416                                 wait_block_group_cache_progress(block_group,
5417                                        num_bytes + empty_cluster + empty_size);
5418                                 goto have_block_group;
5419                         }
5420
5421                         /*
5422                          * at this point we either didn't find a cluster
5423                          * or we weren't able to allocate a block from our
5424                          * cluster.  Free the cluster we've been trying
5425                          * to use, and go to the next block group
5426                          */
5427                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
5428                         spin_unlock(&last_ptr->refill_lock);
5429                         goto loop;
5430                 }
5431
5432 unclustered_alloc:
5433                 spin_lock(&block_group->free_space_ctl->tree_lock);
5434                 if (cached &&
5435                     block_group->free_space_ctl->free_space <
5436                     num_bytes + empty_cluster + empty_size) {
5437                         spin_unlock(&block_group->free_space_ctl->tree_lock);
5438                         goto loop;
5439                 }
5440                 spin_unlock(&block_group->free_space_ctl->tree_lock);
5441
5442                 offset = btrfs_find_space_for_alloc(block_group, search_start,
5443                                                     num_bytes, empty_size);
5444                 /*
5445                  * If we didn't find a chunk, and we haven't failed on this
5446                  * block group before, and this block group is in the middle of
5447                  * caching and we are ok with waiting, then go ahead and wait
5448                  * for progress to be made, and set failed_alloc to true.
5449                  *
5450                  * If failed_alloc is true then we've already waited on this
5451                  * block group once and should move on to the next block group.
5452                  */
5453                 if (!offset && !failed_alloc && !cached &&
5454                     loop > LOOP_CACHING_NOWAIT) {
5455                         wait_block_group_cache_progress(block_group,
5456                                                 num_bytes + empty_size);
5457                         failed_alloc = true;
5458                         goto have_block_group;
5459                 } else if (!offset) {
5460                         if (!cached)
5461                                 have_caching_bg = true;
5462                         goto loop;
5463                 }
5464 checks:
5465                 search_start = stripe_align(root, offset);
5466                 /* move on to the next group */
5467                 if (search_start + num_bytes >= search_end) {
5468                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5469                         goto loop;
5470                 }
5471
5472                 /* move on to the next group */
5473                 if (search_start + num_bytes >
5474                     used_block_group->key.objectid + used_block_group->key.offset) {
5475                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5476                         goto loop;
5477                 }
5478
5479                 if (offset < search_start)
5480                         btrfs_add_free_space(used_block_group, offset,
5481                                              search_start - offset);
5482                 BUG_ON(offset > search_start);
5483
5484                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
5485                                                   alloc_type);
5486                 if (ret == -EAGAIN) {
5487                         btrfs_add_free_space(used_block_group, offset, num_bytes);
5488                         goto loop;
5489                 }
5490
5491                 /* we are all good, lets return */
5492                 ins->objectid = search_start;
5493                 ins->offset = num_bytes;
5494
5495                 if (offset < search_start)
5496                         btrfs_add_free_space(used_block_group, offset,
5497                                              search_start - offset);
5498                 BUG_ON(offset > search_start);
5499                 if (used_block_group != block_group)
5500                         btrfs_put_block_group(used_block_group);
5501                 btrfs_put_block_group(block_group);
5502                 break;
5503 loop:
5504                 failed_cluster_refill = false;
5505                 failed_alloc = false;
5506                 BUG_ON(index != get_block_group_index(block_group));
5507                 if (used_block_group != block_group)
5508                         btrfs_put_block_group(used_block_group);
5509                 btrfs_put_block_group(block_group);
5510         }
5511         up_read(&space_info->groups_sem);
5512
5513         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
5514                 goto search;
5515
5516         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
5517                 goto search;
5518
5519         /* LOOP_FIND_IDEAL, only search caching/cached bg's, and don't wait for
5520          *                      for them to make caching progress.  Also
5521          *                      determine the best possible bg to cache
5522          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
5523          *                      caching kthreads as we move along
5524          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
5525          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
5526          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
5527          *                      again
5528          */
5529         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
5530                 index = 0;
5531                 if (loop == LOOP_FIND_IDEAL && found_uncached_bg) {
5532                         found_uncached_bg = false;
5533                         loop++;
5534                         if (!ideal_cache_percent)
5535                                 goto search;
5536
5537                         /*
5538                          * 1 of the following 2 things have happened so far
5539                          *
5540                          * 1) We found an ideal block group for caching that
5541                          * is mostly full and will cache quickly, so we might
5542                          * as well wait for it.
5543                          *
5544                          * 2) We searched for cached only and we didn't find
5545                          * anything, and we didn't start any caching kthreads
5546                          * either, so chances are we will loop through and
5547                          * start a couple caching kthreads, and then come back
5548                          * around and just wait for them.  This will be slower
5549                          * because we will have 2 caching kthreads reading at
5550                          * the same time when we could have just started one
5551                          * and waited for it to get far enough to give us an
5552                          * allocation, so go ahead and go to the wait caching
5553                          * loop.
5554                          */
5555                         loop = LOOP_CACHING_WAIT;
5556                         search_start = ideal_cache_offset;
5557                         ideal_cache_percent = 0;
5558                         goto ideal_cache;
5559                 } else if (loop == LOOP_FIND_IDEAL) {
5560                         /*
5561                          * Didn't find a uncached bg, wait on anything we find
5562                          * next.
5563                          */
5564                         loop = LOOP_CACHING_WAIT;
5565                         goto search;
5566                 }
5567
5568                 loop++;
5569
5570                 if (loop == LOOP_ALLOC_CHUNK) {
5571                        if (allowed_chunk_alloc) {
5572                                 ret = do_chunk_alloc(trans, root, num_bytes +
5573                                                      2 * 1024 * 1024, data,
5574                                                      CHUNK_ALLOC_LIMITED);
5575                                 allowed_chunk_alloc = 0;
5576                                 if (ret == 1)
5577                                         done_chunk_alloc = 1;
5578                         } else if (!done_chunk_alloc &&
5579                                    space_info->force_alloc ==
5580                                    CHUNK_ALLOC_NO_FORCE) {
5581                                 space_info->force_alloc = CHUNK_ALLOC_LIMITED;
5582                         }
5583
5584                        /*
5585                         * We didn't allocate a chunk, go ahead and drop the
5586                         * empty size and loop again.
5587                         */
5588                        if (!done_chunk_alloc)
5589                                loop = LOOP_NO_EMPTY_SIZE;
5590                 }
5591
5592                 if (loop == LOOP_NO_EMPTY_SIZE) {
5593                         empty_size = 0;
5594                         empty_cluster = 0;
5595                 }
5596
5597                 goto search;
5598         } else if (!ins->objectid) {
5599                 ret = -ENOSPC;
5600         } else if (ins->objectid) {
5601                 ret = 0;
5602         }
5603
5604         return ret;
5605 }
5606
5607 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
5608                             int dump_block_groups)
5609 {
5610         struct btrfs_block_group_cache *cache;
5611         int index = 0;
5612
5613         spin_lock(&info->lock);
5614         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
5615                (unsigned long long)info->flags,
5616                (unsigned long long)(info->total_bytes - info->bytes_used -
5617                                     info->bytes_pinned - info->bytes_reserved -
5618                                     info->bytes_readonly),
5619                (info->full) ? "" : "not ");
5620         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
5621                "reserved=%llu, may_use=%llu, readonly=%llu\n",
5622                (unsigned long long)info->total_bytes,
5623                (unsigned long long)info->bytes_used,
5624                (unsigned long long)info->bytes_pinned,
5625                (unsigned long long)info->bytes_reserved,
5626                (unsigned long long)info->bytes_may_use,
5627                (unsigned long long)info->bytes_readonly);
5628         spin_unlock(&info->lock);
5629
5630         if (!dump_block_groups)
5631                 return;
5632
5633         down_read(&info->groups_sem);
5634 again:
5635         list_for_each_entry(cache, &info->block_groups[index], list) {
5636                 spin_lock(&cache->lock);
5637                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
5638                        "%llu pinned %llu reserved\n",
5639                        (unsigned long long)cache->key.objectid,
5640                        (unsigned long long)cache->key.offset,
5641                        (unsigned long long)btrfs_block_group_used(&cache->item),
5642                        (unsigned long long)cache->pinned,
5643                        (unsigned long long)cache->reserved);
5644                 btrfs_dump_free_space(cache, bytes);
5645                 spin_unlock(&cache->lock);
5646         }
5647         if (++index < BTRFS_NR_RAID_TYPES)
5648                 goto again;
5649         up_read(&info->groups_sem);
5650 }
5651
5652 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
5653                          struct btrfs_root *root,
5654                          u64 num_bytes, u64 min_alloc_size,
5655                          u64 empty_size, u64 hint_byte,
5656                          u64 search_end, struct btrfs_key *ins,
5657                          u64 data)
5658 {
5659         int ret;
5660         u64 search_start = 0;
5661
5662         data = btrfs_get_alloc_profile(root, data);
5663 again:
5664         /*
5665          * the only place that sets empty_size is btrfs_realloc_node, which
5666          * is not called recursively on allocations
5667          */
5668         if (empty_size || root->ref_cows)
5669                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
5670                                      num_bytes + 2 * 1024 * 1024, data,
5671                                      CHUNK_ALLOC_NO_FORCE);
5672
5673         WARN_ON(num_bytes < root->sectorsize);
5674         ret = find_free_extent(trans, root, num_bytes, empty_size,
5675                                search_start, search_end, hint_byte,
5676                                ins, data);
5677
5678         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
5679                 num_bytes = num_bytes >> 1;
5680                 num_bytes = num_bytes & ~(root->sectorsize - 1);
5681                 num_bytes = max(num_bytes, min_alloc_size);
5682                 do_chunk_alloc(trans, root->fs_info->extent_root,
5683                                num_bytes, data, CHUNK_ALLOC_FORCE);
5684                 goto again;
5685         }
5686         if (ret == -ENOSPC && btrfs_test_opt(root, ENOSPC_DEBUG)) {
5687                 struct btrfs_space_info *sinfo;
5688
5689                 sinfo = __find_space_info(root->fs_info, data);
5690                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
5691                        "wanted %llu\n", (unsigned long long)data,
5692                        (unsigned long long)num_bytes);
5693                 dump_space_info(sinfo, num_bytes, 1);
5694         }
5695
5696         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
5697
5698         return ret;
5699 }
5700
5701 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
5702                                         u64 start, u64 len, int pin)
5703 {
5704         struct btrfs_block_group_cache *cache;
5705         int ret = 0;
5706
5707         cache = btrfs_lookup_block_group(root->fs_info, start);
5708         if (!cache) {
5709                 printk(KERN_ERR "Unable to find block group for %llu\n",
5710                        (unsigned long long)start);
5711                 return -ENOSPC;
5712         }
5713
5714         if (btrfs_test_opt(root, DISCARD))
5715                 ret = btrfs_discard_extent(root, start, len, NULL);
5716
5717         if (pin)
5718                 pin_down_extent(root, cache, start, len, 1);
5719         else {
5720                 btrfs_add_free_space(cache, start, len);
5721                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
5722         }
5723         btrfs_put_block_group(cache);
5724
5725         trace_btrfs_reserved_extent_free(root, start, len);
5726
5727         return ret;
5728 }
5729
5730 int btrfs_free_reserved_extent(struct btrfs_root *root,
5731                                         u64 start, u64 len)
5732 {
5733         return __btrfs_free_reserved_extent(root, start, len, 0);
5734 }
5735
5736 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
5737                                        u64 start, u64 len)
5738 {
5739         return __btrfs_free_reserved_extent(root, start, len, 1);
5740 }
5741
5742 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5743                                       struct btrfs_root *root,
5744                                       u64 parent, u64 root_objectid,
5745                                       u64 flags, u64 owner, u64 offset,
5746                                       struct btrfs_key *ins, int ref_mod)
5747 {
5748         int ret;
5749         struct btrfs_fs_info *fs_info = root->fs_info;
5750         struct btrfs_extent_item *extent_item;
5751         struct btrfs_extent_inline_ref *iref;
5752         struct btrfs_path *path;
5753         struct extent_buffer *leaf;
5754         int type;
5755         u32 size;
5756
5757         if (parent > 0)
5758                 type = BTRFS_SHARED_DATA_REF_KEY;
5759         else
5760                 type = BTRFS_EXTENT_DATA_REF_KEY;
5761
5762         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
5763
5764         path = btrfs_alloc_path();
5765         if (!path)
5766                 return -ENOMEM;
5767
5768         path->leave_spinning = 1;
5769         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5770                                       ins, size);
5771         BUG_ON(ret);
5772
5773         leaf = path->nodes[0];
5774         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5775                                      struct btrfs_extent_item);
5776         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
5777         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5778         btrfs_set_extent_flags(leaf, extent_item,
5779                                flags | BTRFS_EXTENT_FLAG_DATA);
5780
5781         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
5782         btrfs_set_extent_inline_ref_type(leaf, iref, type);
5783         if (parent > 0) {
5784                 struct btrfs_shared_data_ref *ref;
5785                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
5786                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5787                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
5788         } else {
5789                 struct btrfs_extent_data_ref *ref;
5790                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
5791                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
5792                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
5793                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
5794                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
5795         }
5796
5797         btrfs_mark_buffer_dirty(path->nodes[0]);
5798         btrfs_free_path(path);
5799
5800         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5801         if (ret) {
5802                 printk(KERN_ERR "btrfs update block group failed for %llu "
5803                        "%llu\n", (unsigned long long)ins->objectid,
5804                        (unsigned long long)ins->offset);
5805                 BUG();
5806         }
5807         return ret;
5808 }
5809
5810 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
5811                                      struct btrfs_root *root,
5812                                      u64 parent, u64 root_objectid,
5813                                      u64 flags, struct btrfs_disk_key *key,
5814                                      int level, struct btrfs_key *ins)
5815 {
5816         int ret;
5817         struct btrfs_fs_info *fs_info = root->fs_info;
5818         struct btrfs_extent_item *extent_item;
5819         struct btrfs_tree_block_info *block_info;
5820         struct btrfs_extent_inline_ref *iref;
5821         struct btrfs_path *path;
5822         struct extent_buffer *leaf;
5823         u32 size = sizeof(*extent_item) + sizeof(*block_info) + sizeof(*iref);
5824
5825         path = btrfs_alloc_path();
5826         if (!path)
5827                 return -ENOMEM;
5828
5829         path->leave_spinning = 1;
5830         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
5831                                       ins, size);
5832         BUG_ON(ret);
5833
5834         leaf = path->nodes[0];
5835         extent_item = btrfs_item_ptr(leaf, path->slots[0],
5836                                      struct btrfs_extent_item);
5837         btrfs_set_extent_refs(leaf, extent_item, 1);
5838         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
5839         btrfs_set_extent_flags(leaf, extent_item,
5840                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
5841         block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
5842
5843         btrfs_set_tree_block_key(leaf, block_info, key);
5844         btrfs_set_tree_block_level(leaf, block_info, level);
5845
5846         iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
5847         if (parent > 0) {
5848                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
5849                 btrfs_set_extent_inline_ref_type(leaf, iref,
5850                                                  BTRFS_SHARED_BLOCK_REF_KEY);
5851                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
5852         } else {
5853                 btrfs_set_extent_inline_ref_type(leaf, iref,
5854                                                  BTRFS_TREE_BLOCK_REF_KEY);
5855                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
5856         }
5857
5858         btrfs_mark_buffer_dirty(leaf);
5859         btrfs_free_path(path);
5860
5861         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
5862         if (ret) {
5863                 printk(KERN_ERR "btrfs update block group failed for %llu "
5864                        "%llu\n", (unsigned long long)ins->objectid,
5865                        (unsigned long long)ins->offset);
5866                 BUG();
5867         }
5868         return ret;
5869 }
5870
5871 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
5872                                      struct btrfs_root *root,
5873                                      u64 root_objectid, u64 owner,
5874                                      u64 offset, struct btrfs_key *ins)
5875 {
5876         int ret;
5877
5878         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
5879
5880         ret = btrfs_add_delayed_data_ref(trans, ins->objectid, ins->offset,
5881                                          0, root_objectid, owner, offset,
5882                                          BTRFS_ADD_DELAYED_EXTENT, NULL);
5883         return ret;
5884 }
5885
5886 /*
5887  * this is used by the tree logging recovery code.  It records that
5888  * an extent has been allocated and makes sure to clear the free
5889  * space cache bits as well
5890  */
5891 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
5892                                    struct btrfs_root *root,
5893                                    u64 root_objectid, u64 owner, u64 offset,
5894                                    struct btrfs_key *ins)
5895 {
5896         int ret;
5897         struct btrfs_block_group_cache *block_group;
5898         struct btrfs_caching_control *caching_ctl;
5899         u64 start = ins->objectid;
5900         u64 num_bytes = ins->offset;
5901
5902         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
5903         cache_block_group(block_group, trans, NULL, 0);
5904         caching_ctl = get_caching_control(block_group);
5905
5906         if (!caching_ctl) {
5907                 BUG_ON(!block_group_cache_done(block_group));
5908                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5909                 BUG_ON(ret);
5910         } else {
5911                 mutex_lock(&caching_ctl->mutex);
5912
5913                 if (start >= caching_ctl->progress) {
5914                         ret = add_excluded_extent(root, start, num_bytes);
5915                         BUG_ON(ret);
5916                 } else if (start + num_bytes <= caching_ctl->progress) {
5917                         ret = btrfs_remove_free_space(block_group,
5918                                                       start, num_bytes);
5919                         BUG_ON(ret);
5920                 } else {
5921                         num_bytes = caching_ctl->progress - start;
5922                         ret = btrfs_remove_free_space(block_group,
5923                                                       start, num_bytes);
5924                         BUG_ON(ret);
5925
5926                         start = caching_ctl->progress;
5927                         num_bytes = ins->objectid + ins->offset -
5928                                     caching_ctl->progress;
5929                         ret = add_excluded_extent(root, start, num_bytes);
5930                         BUG_ON(ret);
5931                 }
5932
5933                 mutex_unlock(&caching_ctl->mutex);
5934                 put_caching_control(caching_ctl);
5935         }
5936
5937         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
5938                                           RESERVE_ALLOC_NO_ACCOUNT);
5939         BUG_ON(ret);
5940         btrfs_put_block_group(block_group);
5941         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
5942                                          0, owner, offset, ins, 1);
5943         return ret;
5944 }
5945
5946 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
5947                                             struct btrfs_root *root,
5948                                             u64 bytenr, u32 blocksize,
5949                                             int level)
5950 {
5951         struct extent_buffer *buf;
5952
5953         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
5954         if (!buf)
5955                 return ERR_PTR(-ENOMEM);
5956         btrfs_set_header_generation(buf, trans->transid);
5957         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
5958         btrfs_tree_lock(buf);
5959         clean_tree_block(trans, root, buf);
5960
5961         btrfs_set_lock_blocking(buf);
5962         btrfs_set_buffer_uptodate(buf);
5963
5964         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
5965                 /*
5966                  * we allow two log transactions at a time, use different
5967                  * EXENT bit to differentiate dirty pages.
5968                  */
5969                 if (root->log_transid % 2 == 0)
5970                         set_extent_dirty(&root->dirty_log_pages, buf->start,
5971                                         buf->start + buf->len - 1, GFP_NOFS);
5972                 else
5973                         set_extent_new(&root->dirty_log_pages, buf->start,
5974                                         buf->start + buf->len - 1, GFP_NOFS);
5975         } else {
5976                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
5977                          buf->start + buf->len - 1, GFP_NOFS);
5978         }
5979         trans->blocks_used++;
5980         /* this returns a buffer locked for blocking */
5981         return buf;
5982 }
5983
5984 static struct btrfs_block_rsv *
5985 use_block_rsv(struct btrfs_trans_handle *trans,
5986               struct btrfs_root *root, u32 blocksize)
5987 {
5988         struct btrfs_block_rsv *block_rsv;
5989         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5990         int ret;
5991
5992         block_rsv = get_block_rsv(trans, root);
5993
5994         if (block_rsv->size == 0) {
5995                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
5996                 /*
5997                  * If we couldn't reserve metadata bytes try and use some from
5998                  * the global reserve.
5999                  */
6000                 if (ret && block_rsv != global_rsv) {
6001                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6002                         if (!ret)
6003                                 return global_rsv;
6004                         return ERR_PTR(ret);
6005                 } else if (ret) {
6006                         return ERR_PTR(ret);
6007                 }
6008                 return block_rsv;
6009         }
6010
6011         ret = block_rsv_use_bytes(block_rsv, blocksize);
6012         if (!ret)
6013                 return block_rsv;
6014         if (ret) {
6015                 static DEFINE_RATELIMIT_STATE(_rs,
6016                                 DEFAULT_RATELIMIT_INTERVAL,
6017                                 /*DEFAULT_RATELIMIT_BURST*/ 2);
6018                 if (__ratelimit(&_rs)) {
6019                         printk(KERN_DEBUG "btrfs: block rsv returned %d\n", ret);
6020                         WARN_ON(1);
6021                 }
6022                 ret = reserve_metadata_bytes(root, block_rsv, blocksize, 0);
6023                 if (!ret) {
6024                         return block_rsv;
6025                 } else if (ret && block_rsv != global_rsv) {
6026                         ret = block_rsv_use_bytes(global_rsv, blocksize);
6027                         if (!ret)
6028                                 return global_rsv;
6029                 }
6030         }
6031
6032         return ERR_PTR(-ENOSPC);
6033 }
6034
6035 static void unuse_block_rsv(struct btrfs_block_rsv *block_rsv, u32 blocksize)
6036 {
6037         block_rsv_add_bytes(block_rsv, blocksize, 0);
6038         block_rsv_release_bytes(block_rsv, NULL, 0);
6039 }
6040
6041 /*
6042  * finds a free extent and does all the dirty work required for allocation
6043  * returns the key for the extent through ins, and a tree buffer for
6044  * the first block of the extent through buf.
6045  *
6046  * returns the tree buffer or NULL.
6047  */
6048 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
6049                                         struct btrfs_root *root, u32 blocksize,
6050                                         u64 parent, u64 root_objectid,
6051                                         struct btrfs_disk_key *key, int level,
6052                                         u64 hint, u64 empty_size)
6053 {
6054         struct btrfs_key ins;
6055         struct btrfs_block_rsv *block_rsv;
6056         struct extent_buffer *buf;
6057         u64 flags = 0;
6058         int ret;
6059
6060
6061         block_rsv = use_block_rsv(trans, root, blocksize);
6062         if (IS_ERR(block_rsv))
6063                 return ERR_CAST(block_rsv);
6064
6065         ret = btrfs_reserve_extent(trans, root, blocksize, blocksize,
6066                                    empty_size, hint, (u64)-1, &ins, 0);
6067         if (ret) {
6068                 unuse_block_rsv(block_rsv, blocksize);
6069                 return ERR_PTR(ret);
6070         }
6071
6072         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
6073                                     blocksize, level);
6074         BUG_ON(IS_ERR(buf));
6075
6076         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
6077                 if (parent == 0)
6078                         parent = ins.objectid;
6079                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
6080         } else
6081                 BUG_ON(parent > 0);
6082
6083         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
6084                 struct btrfs_delayed_extent_op *extent_op;
6085                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
6086                 BUG_ON(!extent_op);
6087                 if (key)
6088                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
6089                 else
6090                         memset(&extent_op->key, 0, sizeof(extent_op->key));
6091                 extent_op->flags_to_set = flags;
6092                 extent_op->update_key = 1;
6093                 extent_op->update_flags = 1;
6094                 extent_op->is_data = 0;
6095
6096                 ret = btrfs_add_delayed_tree_ref(trans, ins.objectid,
6097                                         ins.offset, parent, root_objectid,
6098                                         level, BTRFS_ADD_DELAYED_EXTENT,
6099                                         extent_op);
6100                 BUG_ON(ret);
6101         }
6102         return buf;
6103 }
6104
6105 struct walk_control {
6106         u64 refs[BTRFS_MAX_LEVEL];
6107         u64 flags[BTRFS_MAX_LEVEL];
6108         struct btrfs_key update_progress;
6109         int stage;
6110         int level;
6111         int shared_level;
6112         int update_ref;
6113         int keep_locks;
6114         int reada_slot;
6115         int reada_count;
6116 };
6117
6118 #define DROP_REFERENCE  1
6119 #define UPDATE_BACKREF  2
6120
6121 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
6122                                      struct btrfs_root *root,
6123                                      struct walk_control *wc,
6124                                      struct btrfs_path *path)
6125 {
6126         u64 bytenr;
6127         u64 generation;
6128         u64 refs;
6129         u64 flags;
6130         u32 nritems;
6131         u32 blocksize;
6132         struct btrfs_key key;
6133         struct extent_buffer *eb;
6134         int ret;
6135         int slot;
6136         int nread = 0;
6137
6138         if (path->slots[wc->level] < wc->reada_slot) {
6139                 wc->reada_count = wc->reada_count * 2 / 3;
6140                 wc->reada_count = max(wc->reada_count, 2);
6141         } else {
6142                 wc->reada_count = wc->reada_count * 3 / 2;
6143                 wc->reada_count = min_t(int, wc->reada_count,
6144                                         BTRFS_NODEPTRS_PER_BLOCK(root));
6145         }
6146
6147         eb = path->nodes[wc->level];
6148         nritems = btrfs_header_nritems(eb);
6149         blocksize = btrfs_level_size(root, wc->level - 1);
6150
6151         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
6152                 if (nread >= wc->reada_count)
6153                         break;
6154
6155                 cond_resched();
6156                 bytenr = btrfs_node_blockptr(eb, slot);
6157                 generation = btrfs_node_ptr_generation(eb, slot);
6158
6159                 if (slot == path->slots[wc->level])
6160                         goto reada;
6161
6162                 if (wc->stage == UPDATE_BACKREF &&
6163                     generation <= root->root_key.offset)
6164                         continue;
6165
6166                 /* We don't lock the tree block, it's OK to be racy here */
6167                 ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6168                                                &refs, &flags);
6169                 BUG_ON(ret);
6170                 BUG_ON(refs == 0);
6171
6172                 if (wc->stage == DROP_REFERENCE) {
6173                         if (refs == 1)
6174                                 goto reada;
6175
6176                         if (wc->level == 1 &&
6177                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6178                                 continue;
6179                         if (!wc->update_ref ||
6180                             generation <= root->root_key.offset)
6181                                 continue;
6182                         btrfs_node_key_to_cpu(eb, &key, slot);
6183                         ret = btrfs_comp_cpu_keys(&key,
6184                                                   &wc->update_progress);
6185                         if (ret < 0)
6186                                 continue;
6187                 } else {
6188                         if (wc->level == 1 &&
6189                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6190                                 continue;
6191                 }
6192 reada:
6193                 ret = readahead_tree_block(root, bytenr, blocksize,
6194                                            generation);
6195                 if (ret)
6196                         break;
6197                 nread++;
6198         }
6199         wc->reada_slot = slot;
6200 }
6201
6202 /*
6203  * hepler to process tree block while walking down the tree.
6204  *
6205  * when wc->stage == UPDATE_BACKREF, this function updates
6206  * back refs for pointers in the block.
6207  *
6208  * NOTE: return value 1 means we should stop walking down.
6209  */
6210 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
6211                                    struct btrfs_root *root,
6212                                    struct btrfs_path *path,
6213                                    struct walk_control *wc, int lookup_info)
6214 {
6215         int level = wc->level;
6216         struct extent_buffer *eb = path->nodes[level];
6217         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6218         int ret;
6219
6220         if (wc->stage == UPDATE_BACKREF &&
6221             btrfs_header_owner(eb) != root->root_key.objectid)
6222                 return 1;
6223
6224         /*
6225          * when reference count of tree block is 1, it won't increase
6226          * again. once full backref flag is set, we never clear it.
6227          */
6228         if (lookup_info &&
6229             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
6230              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
6231                 BUG_ON(!path->locks[level]);
6232                 ret = btrfs_lookup_extent_info(trans, root,
6233                                                eb->start, eb->len,
6234                                                &wc->refs[level],
6235                                                &wc->flags[level]);
6236                 BUG_ON(ret);
6237                 BUG_ON(wc->refs[level] == 0);
6238         }
6239
6240         if (wc->stage == DROP_REFERENCE) {
6241                 if (wc->refs[level] > 1)
6242                         return 1;
6243
6244                 if (path->locks[level] && !wc->keep_locks) {
6245                         btrfs_tree_unlock_rw(eb, path->locks[level]);
6246                         path->locks[level] = 0;
6247                 }
6248                 return 0;
6249         }
6250
6251         /* wc->stage == UPDATE_BACKREF */
6252         if (!(wc->flags[level] & flag)) {
6253                 BUG_ON(!path->locks[level]);
6254                 ret = btrfs_inc_ref(trans, root, eb, 1);
6255                 BUG_ON(ret);
6256                 ret = btrfs_dec_ref(trans, root, eb, 0);
6257                 BUG_ON(ret);
6258                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
6259                                                   eb->len, flag, 0);
6260                 BUG_ON(ret);
6261                 wc->flags[level] |= flag;
6262         }
6263
6264         /*
6265          * the block is shared by multiple trees, so it's not good to
6266          * keep the tree lock
6267          */
6268         if (path->locks[level] && level > 0) {
6269                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6270                 path->locks[level] = 0;
6271         }
6272         return 0;
6273 }
6274
6275 /*
6276  * hepler to process tree block pointer.
6277  *
6278  * when wc->stage == DROP_REFERENCE, this function checks
6279  * reference count of the block pointed to. if the block
6280  * is shared and we need update back refs for the subtree
6281  * rooted at the block, this function changes wc->stage to
6282  * UPDATE_BACKREF. if the block is shared and there is no
6283  * need to update back, this function drops the reference
6284  * to the block.
6285  *
6286  * NOTE: return value 1 means we should stop walking down.
6287  */
6288 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
6289                                  struct btrfs_root *root,
6290                                  struct btrfs_path *path,
6291                                  struct walk_control *wc, int *lookup_info)
6292 {
6293         u64 bytenr;
6294         u64 generation;
6295         u64 parent;
6296         u32 blocksize;
6297         struct btrfs_key key;
6298         struct extent_buffer *next;
6299         int level = wc->level;
6300         int reada = 0;
6301         int ret = 0;
6302
6303         generation = btrfs_node_ptr_generation(path->nodes[level],
6304                                                path->slots[level]);
6305         /*
6306          * if the lower level block was created before the snapshot
6307          * was created, we know there is no need to update back refs
6308          * for the subtree
6309          */
6310         if (wc->stage == UPDATE_BACKREF &&
6311             generation <= root->root_key.offset) {
6312                 *lookup_info = 1;
6313                 return 1;
6314         }
6315
6316         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
6317         blocksize = btrfs_level_size(root, level - 1);
6318
6319         next = btrfs_find_tree_block(root, bytenr, blocksize);
6320         if (!next) {
6321                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
6322                 if (!next)
6323                         return -ENOMEM;
6324                 reada = 1;
6325         }
6326         btrfs_tree_lock(next);
6327         btrfs_set_lock_blocking(next);
6328
6329         ret = btrfs_lookup_extent_info(trans, root, bytenr, blocksize,
6330                                        &wc->refs[level - 1],
6331                                        &wc->flags[level - 1]);
6332         BUG_ON(ret);
6333         BUG_ON(wc->refs[level - 1] == 0);
6334         *lookup_info = 0;
6335
6336         if (wc->stage == DROP_REFERENCE) {
6337                 if (wc->refs[level - 1] > 1) {
6338                         if (level == 1 &&
6339                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6340                                 goto skip;
6341
6342                         if (!wc->update_ref ||
6343                             generation <= root->root_key.offset)
6344                                 goto skip;
6345
6346                         btrfs_node_key_to_cpu(path->nodes[level], &key,
6347                                               path->slots[level]);
6348                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
6349                         if (ret < 0)
6350                                 goto skip;
6351
6352                         wc->stage = UPDATE_BACKREF;
6353                         wc->shared_level = level - 1;
6354                 }
6355         } else {
6356                 if (level == 1 &&
6357                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
6358                         goto skip;
6359         }
6360
6361         if (!btrfs_buffer_uptodate(next, generation)) {
6362                 btrfs_tree_unlock(next);
6363                 free_extent_buffer(next);
6364                 next = NULL;
6365                 *lookup_info = 1;
6366         }
6367
6368         if (!next) {
6369                 if (reada && level == 1)
6370                         reada_walk_down(trans, root, wc, path);
6371                 next = read_tree_block(root, bytenr, blocksize, generation);
6372                 if (!next)
6373                         return -EIO;
6374                 btrfs_tree_lock(next);
6375                 btrfs_set_lock_blocking(next);
6376         }
6377
6378         level--;
6379         BUG_ON(level != btrfs_header_level(next));
6380         path->nodes[level] = next;
6381         path->slots[level] = 0;
6382         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6383         wc->level = level;
6384         if (wc->level == 1)
6385                 wc->reada_slot = 0;
6386         return 0;
6387 skip:
6388         wc->refs[level - 1] = 0;
6389         wc->flags[level - 1] = 0;
6390         if (wc->stage == DROP_REFERENCE) {
6391                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
6392                         parent = path->nodes[level]->start;
6393                 } else {
6394                         BUG_ON(root->root_key.objectid !=
6395                                btrfs_header_owner(path->nodes[level]));
6396                         parent = 0;
6397                 }
6398
6399                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
6400                                         root->root_key.objectid, level - 1, 0);
6401                 BUG_ON(ret);
6402         }
6403         btrfs_tree_unlock(next);
6404         free_extent_buffer(next);
6405         *lookup_info = 1;
6406         return 1;
6407 }
6408
6409 /*
6410  * hepler to process tree block while walking up the tree.
6411  *
6412  * when wc->stage == DROP_REFERENCE, this function drops
6413  * reference count on the block.
6414  *
6415  * when wc->stage == UPDATE_BACKREF, this function changes
6416  * wc->stage back to DROP_REFERENCE if we changed wc->stage
6417  * to UPDATE_BACKREF previously while processing the block.
6418  *
6419  * NOTE: return value 1 means we should stop walking up.
6420  */
6421 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
6422                                  struct btrfs_root *root,
6423                                  struct btrfs_path *path,
6424                                  struct walk_control *wc)
6425 {
6426         int ret;
6427         int level = wc->level;
6428         struct extent_buffer *eb = path->nodes[level];
6429         u64 parent = 0;
6430
6431         if (wc->stage == UPDATE_BACKREF) {
6432                 BUG_ON(wc->shared_level < level);
6433                 if (level < wc->shared_level)
6434                         goto out;
6435
6436                 ret = find_next_key(path, level + 1, &wc->update_progress);
6437                 if (ret > 0)
6438                         wc->update_ref = 0;
6439
6440                 wc->stage = DROP_REFERENCE;
6441                 wc->shared_level = -1;
6442                 path->slots[level] = 0;
6443
6444                 /*
6445                  * check reference count again if the block isn't locked.
6446                  * we should start walking down the tree again if reference
6447                  * count is one.
6448                  */
6449                 if (!path->locks[level]) {
6450                         BUG_ON(level == 0);
6451                         btrfs_tree_lock(eb);
6452                         btrfs_set_lock_blocking(eb);
6453                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6454
6455                         ret = btrfs_lookup_extent_info(trans, root,
6456                                                        eb->start, eb->len,
6457                                                        &wc->refs[level],
6458                                                        &wc->flags[level]);
6459                         BUG_ON(ret);
6460                         BUG_ON(wc->refs[level] == 0);
6461                         if (wc->refs[level] == 1) {
6462                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
6463                                 return 1;
6464                         }
6465                 }
6466         }
6467
6468         /* wc->stage == DROP_REFERENCE */
6469         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
6470
6471         if (wc->refs[level] == 1) {
6472                 if (level == 0) {
6473                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6474                                 ret = btrfs_dec_ref(trans, root, eb, 1);
6475                         else
6476                                 ret = btrfs_dec_ref(trans, root, eb, 0);
6477                         BUG_ON(ret);
6478                 }
6479                 /* make block locked assertion in clean_tree_block happy */
6480                 if (!path->locks[level] &&
6481                     btrfs_header_generation(eb) == trans->transid) {
6482                         btrfs_tree_lock(eb);
6483                         btrfs_set_lock_blocking(eb);
6484                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6485                 }
6486                 clean_tree_block(trans, root, eb);
6487         }
6488
6489         if (eb == root->node) {
6490                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6491                         parent = eb->start;
6492                 else
6493                         BUG_ON(root->root_key.objectid !=
6494                                btrfs_header_owner(eb));
6495         } else {
6496                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
6497                         parent = path->nodes[level + 1]->start;
6498                 else
6499                         BUG_ON(root->root_key.objectid !=
6500                                btrfs_header_owner(path->nodes[level + 1]));
6501         }
6502
6503         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
6504 out:
6505         wc->refs[level] = 0;
6506         wc->flags[level] = 0;
6507         return 0;
6508 }
6509
6510 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
6511                                    struct btrfs_root *root,
6512                                    struct btrfs_path *path,
6513                                    struct walk_control *wc)
6514 {
6515         int level = wc->level;
6516         int lookup_info = 1;
6517         int ret;
6518
6519         while (level >= 0) {
6520                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
6521                 if (ret > 0)
6522                         break;
6523
6524                 if (level == 0)
6525                         break;
6526
6527                 if (path->slots[level] >=
6528                     btrfs_header_nritems(path->nodes[level]))
6529                         break;
6530
6531                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
6532                 if (ret > 0) {
6533                         path->slots[level]++;
6534                         continue;
6535                 } else if (ret < 0)
6536                         return ret;
6537                 level = wc->level;
6538         }
6539         return 0;
6540 }
6541
6542 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
6543                                  struct btrfs_root *root,
6544                                  struct btrfs_path *path,
6545                                  struct walk_control *wc, int max_level)
6546 {
6547         int level = wc->level;
6548         int ret;
6549
6550         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
6551         while (level < max_level && path->nodes[level]) {
6552                 wc->level = level;
6553                 if (path->slots[level] + 1 <
6554                     btrfs_header_nritems(path->nodes[level])) {
6555                         path->slots[level]++;
6556                         return 0;
6557                 } else {
6558                         ret = walk_up_proc(trans, root, path, wc);
6559                         if (ret > 0)
6560                                 return 0;
6561
6562                         if (path->locks[level]) {
6563                                 btrfs_tree_unlock_rw(path->nodes[level],
6564                                                      path->locks[level]);
6565                                 path->locks[level] = 0;
6566                         }
6567                         free_extent_buffer(path->nodes[level]);
6568                         path->nodes[level] = NULL;
6569                         level++;
6570                 }
6571         }
6572         return 1;
6573 }
6574
6575 /*
6576  * drop a subvolume tree.
6577  *
6578  * this function traverses the tree freeing any blocks that only
6579  * referenced by the tree.
6580  *
6581  * when a shared tree block is found. this function decreases its
6582  * reference count by one. if update_ref is true, this function
6583  * also make sure backrefs for the shared block and all lower level
6584  * blocks are properly updated.
6585  */
6586 void btrfs_drop_snapshot(struct btrfs_root *root,
6587                          struct btrfs_block_rsv *block_rsv, int update_ref)
6588 {
6589         struct btrfs_path *path;
6590         struct btrfs_trans_handle *trans;
6591         struct btrfs_root *tree_root = root->fs_info->tree_root;
6592         struct btrfs_root_item *root_item = &root->root_item;
6593         struct walk_control *wc;
6594         struct btrfs_key key;
6595         int err = 0;
6596         int ret;
6597         int level;
6598
6599         path = btrfs_alloc_path();
6600         if (!path) {
6601                 err = -ENOMEM;
6602                 goto out;
6603         }
6604
6605         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6606         if (!wc) {
6607                 btrfs_free_path(path);
6608                 err = -ENOMEM;
6609                 goto out;
6610         }
6611
6612         trans = btrfs_start_transaction(tree_root, 0);
6613         BUG_ON(IS_ERR(trans));
6614
6615         if (block_rsv)
6616                 trans->block_rsv = block_rsv;
6617
6618         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
6619                 level = btrfs_header_level(root->node);
6620                 path->nodes[level] = btrfs_lock_root_node(root);
6621                 btrfs_set_lock_blocking(path->nodes[level]);
6622                 path->slots[level] = 0;
6623                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6624                 memset(&wc->update_progress, 0,
6625                        sizeof(wc->update_progress));
6626         } else {
6627                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
6628                 memcpy(&wc->update_progress, &key,
6629                        sizeof(wc->update_progress));
6630
6631                 level = root_item->drop_level;
6632                 BUG_ON(level == 0);
6633                 path->lowest_level = level;
6634                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6635                 path->lowest_level = 0;
6636                 if (ret < 0) {
6637                         err = ret;
6638                         goto out_free;
6639                 }
6640                 WARN_ON(ret > 0);
6641
6642                 /*
6643                  * unlock our path, this is safe because only this
6644                  * function is allowed to delete this snapshot
6645                  */
6646                 btrfs_unlock_up_safe(path, 0);
6647
6648                 level = btrfs_header_level(root->node);
6649                 while (1) {
6650                         btrfs_tree_lock(path->nodes[level]);
6651                         btrfs_set_lock_blocking(path->nodes[level]);
6652
6653                         ret = btrfs_lookup_extent_info(trans, root,
6654                                                 path->nodes[level]->start,
6655                                                 path->nodes[level]->len,
6656                                                 &wc->refs[level],
6657                                                 &wc->flags[level]);
6658                         BUG_ON(ret);
6659                         BUG_ON(wc->refs[level] == 0);
6660
6661                         if (level == root_item->drop_level)
6662                                 break;
6663
6664                         btrfs_tree_unlock(path->nodes[level]);
6665                         WARN_ON(wc->refs[level] != 1);
6666                         level--;
6667                 }
6668         }
6669
6670         wc->level = level;
6671         wc->shared_level = -1;
6672         wc->stage = DROP_REFERENCE;
6673         wc->update_ref = update_ref;
6674         wc->keep_locks = 0;
6675         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6676
6677         while (1) {
6678                 ret = walk_down_tree(trans, root, path, wc);
6679                 if (ret < 0) {
6680                         err = ret;
6681                         break;
6682                 }
6683
6684                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
6685                 if (ret < 0) {
6686                         err = ret;
6687                         break;
6688                 }
6689
6690                 if (ret > 0) {
6691                         BUG_ON(wc->stage != DROP_REFERENCE);
6692                         break;
6693                 }
6694
6695                 if (wc->stage == DROP_REFERENCE) {
6696                         level = wc->level;
6697                         btrfs_node_key(path->nodes[level],
6698                                        &root_item->drop_progress,
6699                                        path->slots[level]);
6700                         root_item->drop_level = level;
6701                 }
6702
6703                 BUG_ON(wc->level == 0);
6704                 if (btrfs_should_end_transaction(trans, tree_root)) {
6705                         ret = btrfs_update_root(trans, tree_root,
6706                                                 &root->root_key,
6707                                                 root_item);
6708                         BUG_ON(ret);
6709
6710                         btrfs_end_transaction_throttle(trans, tree_root);
6711                         trans = btrfs_start_transaction(tree_root, 0);
6712                         BUG_ON(IS_ERR(trans));
6713                         if (block_rsv)
6714                                 trans->block_rsv = block_rsv;
6715                 }
6716         }
6717         btrfs_release_path(path);
6718         BUG_ON(err);
6719
6720         ret = btrfs_del_root(trans, tree_root, &root->root_key);
6721         BUG_ON(ret);
6722
6723         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
6724                 ret = btrfs_find_last_root(tree_root, root->root_key.objectid,
6725                                            NULL, NULL);
6726                 BUG_ON(ret < 0);
6727                 if (ret > 0) {
6728                         /* if we fail to delete the orphan item this time
6729                          * around, it'll get picked up the next time.
6730                          *
6731                          * The most common failure here is just -ENOENT.
6732                          */
6733                         btrfs_del_orphan_item(trans, tree_root,
6734                                               root->root_key.objectid);
6735                 }
6736         }
6737
6738         if (root->in_radix) {
6739                 btrfs_free_fs_root(tree_root->fs_info, root);
6740         } else {
6741                 free_extent_buffer(root->node);
6742                 free_extent_buffer(root->commit_root);
6743                 kfree(root);
6744         }
6745 out_free:
6746         btrfs_end_transaction_throttle(trans, tree_root);
6747         kfree(wc);
6748         btrfs_free_path(path);
6749 out:
6750         if (err)
6751                 btrfs_std_error(root->fs_info, err);
6752         return;
6753 }
6754
6755 /*
6756  * drop subtree rooted at tree block 'node'.
6757  *
6758  * NOTE: this function will unlock and release tree block 'node'
6759  */
6760 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
6761                         struct btrfs_root *root,
6762                         struct extent_buffer *node,
6763                         struct extent_buffer *parent)
6764 {
6765         struct btrfs_path *path;
6766         struct walk_control *wc;
6767         int level;
6768         int parent_level;
6769         int ret = 0;
6770         int wret;
6771
6772         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
6773
6774         path = btrfs_alloc_path();
6775         if (!path)
6776                 return -ENOMEM;
6777
6778         wc = kzalloc(sizeof(*wc), GFP_NOFS);
6779         if (!wc) {
6780                 btrfs_free_path(path);
6781                 return -ENOMEM;
6782         }
6783
6784         btrfs_assert_tree_locked(parent);
6785         parent_level = btrfs_header_level(parent);
6786         extent_buffer_get(parent);
6787         path->nodes[parent_level] = parent;
6788         path->slots[parent_level] = btrfs_header_nritems(parent);
6789
6790         btrfs_assert_tree_locked(node);
6791         level = btrfs_header_level(node);
6792         path->nodes[level] = node;
6793         path->slots[level] = 0;
6794         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
6795
6796         wc->refs[parent_level] = 1;
6797         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
6798         wc->level = level;
6799         wc->shared_level = -1;
6800         wc->stage = DROP_REFERENCE;
6801         wc->update_ref = 0;
6802         wc->keep_locks = 1;
6803         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
6804
6805         while (1) {
6806                 wret = walk_down_tree(trans, root, path, wc);
6807                 if (wret < 0) {
6808                         ret = wret;
6809                         break;
6810                 }
6811
6812                 wret = walk_up_tree(trans, root, path, wc, parent_level);
6813                 if (wret < 0)
6814                         ret = wret;
6815                 if (wret != 0)
6816                         break;
6817         }
6818
6819         kfree(wc);
6820         btrfs_free_path(path);
6821         return ret;
6822 }
6823
6824 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
6825 {
6826         u64 num_devices;
6827         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
6828                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
6829
6830         if (root->fs_info->balance_ctl) {
6831                 struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
6832                 u64 tgt = 0;
6833
6834                 /* pick restriper's target profile and return */
6835                 if (flags & BTRFS_BLOCK_GROUP_DATA &&
6836                     bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
6837                         tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
6838                 } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
6839                            bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
6840                         tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
6841                 } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
6842                            bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
6843                         tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
6844                 }
6845
6846                 if (tgt) {
6847                         /* extended -> chunk profile */
6848                         tgt &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
6849                         return tgt;
6850                 }
6851         }
6852
6853         /*
6854          * we add in the count of missing devices because we want
6855          * to make sure that any RAID levels on a degraded FS
6856          * continue to be honored.
6857          */
6858         num_devices = root->fs_info->fs_devices->rw_devices +
6859                 root->fs_info->fs_devices->missing_devices;
6860
6861         if (num_devices == 1) {
6862                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6863                 stripped = flags & ~stripped;
6864
6865                 /* turn raid0 into single device chunks */
6866                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
6867                         return stripped;
6868
6869                 /* turn mirroring into duplication */
6870                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
6871                              BTRFS_BLOCK_GROUP_RAID10))
6872                         return stripped | BTRFS_BLOCK_GROUP_DUP;
6873                 return flags;
6874         } else {
6875                 /* they already had raid on here, just return */
6876                 if (flags & stripped)
6877                         return flags;
6878
6879                 stripped |= BTRFS_BLOCK_GROUP_DUP;
6880                 stripped = flags & ~stripped;
6881
6882                 /* switch duplicated blocks with raid1 */
6883                 if (flags & BTRFS_BLOCK_GROUP_DUP)
6884                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
6885
6886                 /* turn single device chunks into raid0 */
6887                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
6888         }
6889         return flags;
6890 }
6891
6892 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
6893 {
6894         struct btrfs_space_info *sinfo = cache->space_info;
6895         u64 num_bytes;
6896         u64 min_allocable_bytes;
6897         int ret = -ENOSPC;
6898
6899
6900         /*
6901          * We need some metadata space and system metadata space for
6902          * allocating chunks in some corner cases until we force to set
6903          * it to be readonly.
6904          */
6905         if ((sinfo->flags &
6906              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
6907             !force)
6908                 min_allocable_bytes = 1 * 1024 * 1024;
6909         else
6910                 min_allocable_bytes = 0;
6911
6912         spin_lock(&sinfo->lock);
6913         spin_lock(&cache->lock);
6914
6915         if (cache->ro) {
6916                 ret = 0;
6917                 goto out;
6918         }
6919
6920         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
6921                     cache->bytes_super - btrfs_block_group_used(&cache->item);
6922
6923         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
6924             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
6925             min_allocable_bytes <= sinfo->total_bytes) {
6926                 sinfo->bytes_readonly += num_bytes;
6927                 cache->ro = 1;
6928                 ret = 0;
6929         }
6930 out:
6931         spin_unlock(&cache->lock);
6932         spin_unlock(&sinfo->lock);
6933         return ret;
6934 }
6935
6936 int btrfs_set_block_group_ro(struct btrfs_root *root,
6937                              struct btrfs_block_group_cache *cache)
6938
6939 {
6940         struct btrfs_trans_handle *trans;
6941         u64 alloc_flags;
6942         int ret;
6943
6944         BUG_ON(cache->ro);
6945
6946         trans = btrfs_join_transaction(root);
6947         BUG_ON(IS_ERR(trans));
6948
6949         alloc_flags = update_block_group_flags(root, cache->flags);
6950         if (alloc_flags != cache->flags)
6951                 do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6952                                CHUNK_ALLOC_FORCE);
6953
6954         ret = set_block_group_ro(cache, 0);
6955         if (!ret)
6956                 goto out;
6957         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
6958         ret = do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6959                              CHUNK_ALLOC_FORCE);
6960         if (ret < 0)
6961                 goto out;
6962         ret = set_block_group_ro(cache, 0);
6963 out:
6964         btrfs_end_transaction(trans, root);
6965         return ret;
6966 }
6967
6968 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
6969                             struct btrfs_root *root, u64 type)
6970 {
6971         u64 alloc_flags = get_alloc_profile(root, type);
6972         return do_chunk_alloc(trans, root, 2 * 1024 * 1024, alloc_flags,
6973                               CHUNK_ALLOC_FORCE);
6974 }
6975
6976 /*
6977  * helper to account the unused space of all the readonly block group in the
6978  * list. takes mirrors into account.
6979  */
6980 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
6981 {
6982         struct btrfs_block_group_cache *block_group;
6983         u64 free_bytes = 0;
6984         int factor;
6985
6986         list_for_each_entry(block_group, groups_list, list) {
6987                 spin_lock(&block_group->lock);
6988
6989                 if (!block_group->ro) {
6990                         spin_unlock(&block_group->lock);
6991                         continue;
6992                 }
6993
6994                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
6995                                           BTRFS_BLOCK_GROUP_RAID10 |
6996                                           BTRFS_BLOCK_GROUP_DUP))
6997                         factor = 2;
6998                 else
6999                         factor = 1;
7000
7001                 free_bytes += (block_group->key.offset -
7002                                btrfs_block_group_used(&block_group->item)) *
7003                                factor;
7004
7005                 spin_unlock(&block_group->lock);
7006         }
7007
7008         return free_bytes;
7009 }
7010
7011 /*
7012  * helper to account the unused space of all the readonly block group in the
7013  * space_info. takes mirrors into account.
7014  */
7015 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
7016 {
7017         int i;
7018         u64 free_bytes = 0;
7019
7020         spin_lock(&sinfo->lock);
7021
7022         for(i = 0; i < BTRFS_NR_RAID_TYPES; i++)
7023                 if (!list_empty(&sinfo->block_groups[i]))
7024                         free_bytes += __btrfs_get_ro_block_group_free_space(
7025                                                 &sinfo->block_groups[i]);
7026
7027         spin_unlock(&sinfo->lock);
7028
7029         return free_bytes;
7030 }
7031
7032 int btrfs_set_block_group_rw(struct btrfs_root *root,
7033                               struct btrfs_block_group_cache *cache)
7034 {
7035         struct btrfs_space_info *sinfo = cache->space_info;
7036         u64 num_bytes;
7037
7038         BUG_ON(!cache->ro);
7039
7040         spin_lock(&sinfo->lock);
7041         spin_lock(&cache->lock);
7042         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7043                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7044         sinfo->bytes_readonly -= num_bytes;
7045         cache->ro = 0;
7046         spin_unlock(&cache->lock);
7047         spin_unlock(&sinfo->lock);
7048         return 0;
7049 }
7050
7051 /*
7052  * checks to see if its even possible to relocate this block group.
7053  *
7054  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
7055  * ok to go ahead and try.
7056  */
7057 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
7058 {
7059         struct btrfs_block_group_cache *block_group;
7060         struct btrfs_space_info *space_info;
7061         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
7062         struct btrfs_device *device;
7063         u64 min_free;
7064         u64 dev_min = 1;
7065         u64 dev_nr = 0;
7066         int index;
7067         int full = 0;
7068         int ret = 0;
7069
7070         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
7071
7072         /* odd, couldn't find the block group, leave it alone */
7073         if (!block_group)
7074                 return -1;
7075
7076         min_free = btrfs_block_group_used(&block_group->item);
7077
7078         /* no bytes used, we're good */
7079         if (!min_free)
7080                 goto out;
7081
7082         space_info = block_group->space_info;
7083         spin_lock(&space_info->lock);
7084
7085         full = space_info->full;
7086
7087         /*
7088          * if this is the last block group we have in this space, we can't
7089          * relocate it unless we're able to allocate a new chunk below.
7090          *
7091          * Otherwise, we need to make sure we have room in the space to handle
7092          * all of the extents from this block group.  If we can, we're good
7093          */
7094         if ((space_info->total_bytes != block_group->key.offset) &&
7095             (space_info->bytes_used + space_info->bytes_reserved +
7096              space_info->bytes_pinned + space_info->bytes_readonly +
7097              min_free < space_info->total_bytes)) {
7098                 spin_unlock(&space_info->lock);
7099                 goto out;
7100         }
7101         spin_unlock(&space_info->lock);
7102
7103         /*
7104          * ok we don't have enough space, but maybe we have free space on our
7105          * devices to allocate new chunks for relocation, so loop through our
7106          * alloc devices and guess if we have enough space.  However, if we
7107          * were marked as full, then we know there aren't enough chunks, and we
7108          * can just return.
7109          */
7110         ret = -1;
7111         if (full)
7112                 goto out;
7113
7114         /*
7115          * index:
7116          *      0: raid10
7117          *      1: raid1
7118          *      2: dup
7119          *      3: raid0
7120          *      4: single
7121          */
7122         index = get_block_group_index(block_group);
7123         if (index == 0) {
7124                 dev_min = 4;
7125                 /* Divide by 2 */
7126                 min_free >>= 1;
7127         } else if (index == 1) {
7128                 dev_min = 2;
7129         } else if (index == 2) {
7130                 /* Multiply by 2 */
7131                 min_free <<= 1;
7132         } else if (index == 3) {
7133                 dev_min = fs_devices->rw_devices;
7134                 do_div(min_free, dev_min);
7135         }
7136
7137         mutex_lock(&root->fs_info->chunk_mutex);
7138         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
7139                 u64 dev_offset;
7140
7141                 /*
7142                  * check to make sure we can actually find a chunk with enough
7143                  * space to fit our block group in.
7144                  */
7145                 if (device->total_bytes > device->bytes_used + min_free) {
7146                         ret = find_free_dev_extent(device, min_free,
7147                                                    &dev_offset, NULL);
7148                         if (!ret)
7149                                 dev_nr++;
7150
7151                         if (dev_nr >= dev_min)
7152                                 break;
7153
7154                         ret = -1;
7155                 }
7156         }
7157         mutex_unlock(&root->fs_info->chunk_mutex);
7158 out:
7159         btrfs_put_block_group(block_group);
7160         return ret;
7161 }
7162
7163 static int find_first_block_group(struct btrfs_root *root,
7164                 struct btrfs_path *path, struct btrfs_key *key)
7165 {
7166         int ret = 0;
7167         struct btrfs_key found_key;
7168         struct extent_buffer *leaf;
7169         int slot;
7170
7171         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
7172         if (ret < 0)
7173                 goto out;
7174
7175         while (1) {
7176                 slot = path->slots[0];
7177                 leaf = path->nodes[0];
7178                 if (slot >= btrfs_header_nritems(leaf)) {
7179                         ret = btrfs_next_leaf(root, path);
7180                         if (ret == 0)
7181                                 continue;
7182                         if (ret < 0)
7183                                 goto out;
7184                         break;
7185                 }
7186                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
7187
7188                 if (found_key.objectid >= key->objectid &&
7189                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
7190                         ret = 0;
7191                         goto out;
7192                 }
7193                 path->slots[0]++;
7194         }
7195 out:
7196         return ret;
7197 }
7198
7199 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
7200 {
7201         struct btrfs_block_group_cache *block_group;
7202         u64 last = 0;
7203
7204         while (1) {
7205                 struct inode *inode;
7206
7207                 block_group = btrfs_lookup_first_block_group(info, last);
7208                 while (block_group) {
7209                         spin_lock(&block_group->lock);
7210                         if (block_group->iref)
7211                                 break;
7212                         spin_unlock(&block_group->lock);
7213                         block_group = next_block_group(info->tree_root,
7214                                                        block_group);
7215                 }
7216                 if (!block_group) {
7217                         if (last == 0)
7218                                 break;
7219                         last = 0;
7220                         continue;
7221                 }
7222
7223                 inode = block_group->inode;
7224                 block_group->iref = 0;
7225                 block_group->inode = NULL;
7226                 spin_unlock(&block_group->lock);
7227                 iput(inode);
7228                 last = block_group->key.objectid + block_group->key.offset;
7229                 btrfs_put_block_group(block_group);
7230         }
7231 }
7232
7233 int btrfs_free_block_groups(struct btrfs_fs_info *info)
7234 {
7235         struct btrfs_block_group_cache *block_group;
7236         struct btrfs_space_info *space_info;
7237         struct btrfs_caching_control *caching_ctl;
7238         struct rb_node *n;
7239
7240         down_write(&info->extent_commit_sem);
7241         while (!list_empty(&info->caching_block_groups)) {
7242                 caching_ctl = list_entry(info->caching_block_groups.next,
7243                                          struct btrfs_caching_control, list);
7244                 list_del(&caching_ctl->list);
7245                 put_caching_control(caching_ctl);
7246         }
7247         up_write(&info->extent_commit_sem);
7248
7249         spin_lock(&info->block_group_cache_lock);
7250         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
7251                 block_group = rb_entry(n, struct btrfs_block_group_cache,
7252                                        cache_node);
7253                 rb_erase(&block_group->cache_node,
7254                          &info->block_group_cache_tree);
7255                 spin_unlock(&info->block_group_cache_lock);
7256
7257                 down_write(&block_group->space_info->groups_sem);
7258                 list_del(&block_group->list);
7259                 up_write(&block_group->space_info->groups_sem);
7260
7261                 if (block_group->cached == BTRFS_CACHE_STARTED)
7262                         wait_block_group_cache_done(block_group);
7263
7264                 /*
7265                  * We haven't cached this block group, which means we could
7266                  * possibly have excluded extents on this block group.
7267                  */
7268                 if (block_group->cached == BTRFS_CACHE_NO)
7269                         free_excluded_extents(info->extent_root, block_group);
7270
7271                 btrfs_remove_free_space_cache(block_group);
7272                 btrfs_put_block_group(block_group);
7273
7274                 spin_lock(&info->block_group_cache_lock);
7275         }
7276         spin_unlock(&info->block_group_cache_lock);
7277
7278         /* now that all the block groups are freed, go through and
7279          * free all the space_info structs.  This is only called during
7280          * the final stages of unmount, and so we know nobody is
7281          * using them.  We call synchronize_rcu() once before we start,
7282          * just to be on the safe side.
7283          */
7284         synchronize_rcu();
7285
7286         release_global_block_rsv(info);
7287
7288         while(!list_empty(&info->space_info)) {
7289                 space_info = list_entry(info->space_info.next,
7290                                         struct btrfs_space_info,
7291                                         list);
7292                 if (space_info->bytes_pinned > 0 ||
7293                     space_info->bytes_reserved > 0 ||
7294                     space_info->bytes_may_use > 0) {
7295                         WARN_ON(1);
7296                         dump_space_info(space_info, 0, 0);
7297                 }
7298                 list_del(&space_info->list);
7299                 kfree(space_info);
7300         }
7301         return 0;
7302 }
7303
7304 static void __link_block_group(struct btrfs_space_info *space_info,
7305                                struct btrfs_block_group_cache *cache)
7306 {
7307         int index = get_block_group_index(cache);
7308
7309         down_write(&space_info->groups_sem);
7310         list_add_tail(&cache->list, &space_info->block_groups[index]);
7311         up_write(&space_info->groups_sem);
7312 }
7313
7314 int btrfs_read_block_groups(struct btrfs_root *root)
7315 {
7316         struct btrfs_path *path;
7317         int ret;
7318         struct btrfs_block_group_cache *cache;
7319         struct btrfs_fs_info *info = root->fs_info;
7320         struct btrfs_space_info *space_info;
7321         struct btrfs_key key;
7322         struct btrfs_key found_key;
7323         struct extent_buffer *leaf;
7324         int need_clear = 0;
7325         u64 cache_gen;
7326
7327         root = info->extent_root;
7328         key.objectid = 0;
7329         key.offset = 0;
7330         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
7331         path = btrfs_alloc_path();
7332         if (!path)
7333                 return -ENOMEM;
7334         path->reada = 1;
7335
7336         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
7337         if (btrfs_test_opt(root, SPACE_CACHE) &&
7338             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
7339                 need_clear = 1;
7340         if (btrfs_test_opt(root, CLEAR_CACHE))
7341                 need_clear = 1;
7342
7343         while (1) {
7344                 ret = find_first_block_group(root, path, &key);
7345                 if (ret > 0)
7346                         break;
7347                 if (ret != 0)
7348                         goto error;
7349                 leaf = path->nodes[0];
7350                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
7351                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
7352                 if (!cache) {
7353                         ret = -ENOMEM;
7354                         goto error;
7355                 }
7356                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7357                                                 GFP_NOFS);
7358                 if (!cache->free_space_ctl) {
7359                         kfree(cache);
7360                         ret = -ENOMEM;
7361                         goto error;
7362                 }
7363
7364                 atomic_set(&cache->count, 1);
7365                 spin_lock_init(&cache->lock);
7366                 cache->fs_info = info;
7367                 INIT_LIST_HEAD(&cache->list);
7368                 INIT_LIST_HEAD(&cache->cluster_list);
7369
7370                 if (need_clear)
7371                         cache->disk_cache_state = BTRFS_DC_CLEAR;
7372
7373                 read_extent_buffer(leaf, &cache->item,
7374                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
7375                                    sizeof(cache->item));
7376                 memcpy(&cache->key, &found_key, sizeof(found_key));
7377
7378                 key.objectid = found_key.objectid + found_key.offset;
7379                 btrfs_release_path(path);
7380                 cache->flags = btrfs_block_group_flags(&cache->item);
7381                 cache->sectorsize = root->sectorsize;
7382
7383                 btrfs_init_free_space_ctl(cache);
7384
7385                 /*
7386                  * We need to exclude the super stripes now so that the space
7387                  * info has super bytes accounted for, otherwise we'll think
7388                  * we have more space than we actually do.
7389                  */
7390                 exclude_super_stripes(root, cache);
7391
7392                 /*
7393                  * check for two cases, either we are full, and therefore
7394                  * don't need to bother with the caching work since we won't
7395                  * find any space, or we are empty, and we can just add all
7396                  * the space in and be done with it.  This saves us _alot_ of
7397                  * time, particularly in the full case.
7398                  */
7399                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
7400                         cache->last_byte_to_unpin = (u64)-1;
7401                         cache->cached = BTRFS_CACHE_FINISHED;
7402                         free_excluded_extents(root, cache);
7403                 } else if (btrfs_block_group_used(&cache->item) == 0) {
7404                         cache->last_byte_to_unpin = (u64)-1;
7405                         cache->cached = BTRFS_CACHE_FINISHED;
7406                         add_new_free_space(cache, root->fs_info,
7407                                            found_key.objectid,
7408                                            found_key.objectid +
7409                                            found_key.offset);
7410                         free_excluded_extents(root, cache);
7411                 }
7412
7413                 ret = update_space_info(info, cache->flags, found_key.offset,
7414                                         btrfs_block_group_used(&cache->item),
7415                                         &space_info);
7416                 BUG_ON(ret);
7417                 cache->space_info = space_info;
7418                 spin_lock(&cache->space_info->lock);
7419                 cache->space_info->bytes_readonly += cache->bytes_super;
7420                 spin_unlock(&cache->space_info->lock);
7421
7422                 __link_block_group(space_info, cache);
7423
7424                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
7425                 BUG_ON(ret);
7426
7427                 set_avail_alloc_bits(root->fs_info, cache->flags);
7428                 if (btrfs_chunk_readonly(root, cache->key.objectid))
7429                         set_block_group_ro(cache, 1);
7430         }
7431
7432         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
7433                 if (!(get_alloc_profile(root, space_info->flags) &
7434                       (BTRFS_BLOCK_GROUP_RAID10 |
7435                        BTRFS_BLOCK_GROUP_RAID1 |
7436                        BTRFS_BLOCK_GROUP_DUP)))
7437                         continue;
7438                 /*
7439                  * avoid allocating from un-mirrored block group if there are
7440                  * mirrored block groups.
7441                  */
7442                 list_for_each_entry(cache, &space_info->block_groups[3], list)
7443                         set_block_group_ro(cache, 1);
7444                 list_for_each_entry(cache, &space_info->block_groups[4], list)
7445                         set_block_group_ro(cache, 1);
7446         }
7447
7448         init_global_block_rsv(info);
7449         ret = 0;
7450 error:
7451         btrfs_free_path(path);
7452         return ret;
7453 }
7454
7455 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
7456                            struct btrfs_root *root, u64 bytes_used,
7457                            u64 type, u64 chunk_objectid, u64 chunk_offset,
7458                            u64 size)
7459 {
7460         int ret;
7461         struct btrfs_root *extent_root;
7462         struct btrfs_block_group_cache *cache;
7463
7464         extent_root = root->fs_info->extent_root;
7465
7466         root->fs_info->last_trans_log_full_commit = trans->transid;
7467
7468         cache = kzalloc(sizeof(*cache), GFP_NOFS);
7469         if (!cache)
7470                 return -ENOMEM;
7471         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
7472                                         GFP_NOFS);
7473         if (!cache->free_space_ctl) {
7474                 kfree(cache);
7475                 return -ENOMEM;
7476         }
7477
7478         cache->key.objectid = chunk_offset;
7479         cache->key.offset = size;
7480         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
7481         cache->sectorsize = root->sectorsize;
7482         cache->fs_info = root->fs_info;
7483
7484         atomic_set(&cache->count, 1);
7485         spin_lock_init(&cache->lock);
7486         INIT_LIST_HEAD(&cache->list);
7487         INIT_LIST_HEAD(&cache->cluster_list);
7488
7489         btrfs_init_free_space_ctl(cache);
7490
7491         btrfs_set_block_group_used(&cache->item, bytes_used);
7492         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
7493         cache->flags = type;
7494         btrfs_set_block_group_flags(&cache->item, type);
7495
7496         cache->last_byte_to_unpin = (u64)-1;
7497         cache->cached = BTRFS_CACHE_FINISHED;
7498         exclude_super_stripes(root, cache);
7499
7500         add_new_free_space(cache, root->fs_info, chunk_offset,
7501                            chunk_offset + size);
7502
7503         free_excluded_extents(root, cache);
7504
7505         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
7506                                 &cache->space_info);
7507         BUG_ON(ret);
7508         update_global_block_rsv(root->fs_info);
7509
7510         spin_lock(&cache->space_info->lock);
7511         cache->space_info->bytes_readonly += cache->bytes_super;
7512         spin_unlock(&cache->space_info->lock);
7513
7514         __link_block_group(cache->space_info, cache);
7515
7516         ret = btrfs_add_block_group_cache(root->fs_info, cache);
7517         BUG_ON(ret);
7518
7519         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
7520                                 sizeof(cache->item));
7521         BUG_ON(ret);
7522
7523         set_avail_alloc_bits(extent_root->fs_info, type);
7524
7525         return 0;
7526 }
7527
7528 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
7529 {
7530         u64 extra_flags = flags & BTRFS_BLOCK_GROUP_PROFILE_MASK;
7531
7532         /* chunk -> extended profile */
7533         if (extra_flags == 0)
7534                 extra_flags = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
7535
7536         if (flags & BTRFS_BLOCK_GROUP_DATA)
7537                 fs_info->avail_data_alloc_bits &= ~extra_flags;
7538         if (flags & BTRFS_BLOCK_GROUP_METADATA)
7539                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
7540         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
7541                 fs_info->avail_system_alloc_bits &= ~extra_flags;
7542 }
7543
7544 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
7545                              struct btrfs_root *root, u64 group_start)
7546 {
7547         struct btrfs_path *path;
7548         struct btrfs_block_group_cache *block_group;
7549         struct btrfs_free_cluster *cluster;
7550         struct btrfs_root *tree_root = root->fs_info->tree_root;
7551         struct btrfs_key key;
7552         struct inode *inode;
7553         int ret;
7554         int index;
7555         int factor;
7556
7557         root = root->fs_info->extent_root;
7558
7559         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
7560         BUG_ON(!block_group);
7561         BUG_ON(!block_group->ro);
7562
7563         /*
7564          * Free the reserved super bytes from this block group before
7565          * remove it.
7566          */
7567         free_excluded_extents(root, block_group);
7568
7569         memcpy(&key, &block_group->key, sizeof(key));
7570         index = get_block_group_index(block_group);
7571         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
7572                                   BTRFS_BLOCK_GROUP_RAID1 |
7573                                   BTRFS_BLOCK_GROUP_RAID10))
7574                 factor = 2;
7575         else
7576                 factor = 1;
7577
7578         /* make sure this block group isn't part of an allocation cluster */
7579         cluster = &root->fs_info->data_alloc_cluster;
7580         spin_lock(&cluster->refill_lock);
7581         btrfs_return_cluster_to_free_space(block_group, cluster);
7582         spin_unlock(&cluster->refill_lock);
7583
7584         /*
7585          * make sure this block group isn't part of a metadata
7586          * allocation cluster
7587          */
7588         cluster = &root->fs_info->meta_alloc_cluster;
7589         spin_lock(&cluster->refill_lock);
7590         btrfs_return_cluster_to_free_space(block_group, cluster);
7591         spin_unlock(&cluster->refill_lock);
7592
7593         path = btrfs_alloc_path();
7594         if (!path) {
7595                 ret = -ENOMEM;
7596                 goto out;
7597         }
7598
7599         inode = lookup_free_space_inode(tree_root, block_group, path);
7600         if (!IS_ERR(inode)) {
7601                 ret = btrfs_orphan_add(trans, inode);
7602                 BUG_ON(ret);
7603                 clear_nlink(inode);
7604                 /* One for the block groups ref */
7605                 spin_lock(&block_group->lock);
7606                 if (block_group->iref) {
7607                         block_group->iref = 0;
7608                         block_group->inode = NULL;
7609                         spin_unlock(&block_group->lock);
7610                         iput(inode);
7611                 } else {
7612                         spin_unlock(&block_group->lock);
7613                 }
7614                 /* One for our lookup ref */
7615                 btrfs_add_delayed_iput(inode);
7616         }
7617
7618         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
7619         key.offset = block_group->key.objectid;
7620         key.type = 0;
7621
7622         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
7623         if (ret < 0)
7624                 goto out;
7625         if (ret > 0)
7626                 btrfs_release_path(path);
7627         if (ret == 0) {
7628                 ret = btrfs_del_item(trans, tree_root, path);
7629                 if (ret)
7630                         goto out;
7631                 btrfs_release_path(path);
7632         }
7633
7634         spin_lock(&root->fs_info->block_group_cache_lock);
7635         rb_erase(&block_group->cache_node,
7636                  &root->fs_info->block_group_cache_tree);
7637         spin_unlock(&root->fs_info->block_group_cache_lock);
7638
7639         down_write(&block_group->space_info->groups_sem);
7640         /*
7641          * we must use list_del_init so people can check to see if they
7642          * are still on the list after taking the semaphore
7643          */
7644         list_del_init(&block_group->list);
7645         if (list_empty(&block_group->space_info->block_groups[index]))
7646                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
7647         up_write(&block_group->space_info->groups_sem);
7648
7649         if (block_group->cached == BTRFS_CACHE_STARTED)
7650                 wait_block_group_cache_done(block_group);
7651
7652         btrfs_remove_free_space_cache(block_group);
7653
7654         spin_lock(&block_group->space_info->lock);
7655         block_group->space_info->total_bytes -= block_group->key.offset;
7656         block_group->space_info->bytes_readonly -= block_group->key.offset;
7657         block_group->space_info->disk_total -= block_group->key.offset * factor;
7658         spin_unlock(&block_group->space_info->lock);
7659
7660         memcpy(&key, &block_group->key, sizeof(key));
7661
7662         btrfs_clear_space_info_full(root->fs_info);
7663
7664         btrfs_put_block_group(block_group);
7665         btrfs_put_block_group(block_group);
7666
7667         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
7668         if (ret > 0)
7669                 ret = -EIO;
7670         if (ret < 0)
7671                 goto out;
7672
7673         ret = btrfs_del_item(trans, root, path);
7674 out:
7675         btrfs_free_path(path);
7676         return ret;
7677 }
7678
7679 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
7680 {
7681         struct btrfs_space_info *space_info;
7682         struct btrfs_super_block *disk_super;
7683         u64 features;
7684         u64 flags;
7685         int mixed = 0;
7686         int ret;
7687
7688         disk_super = fs_info->super_copy;
7689         if (!btrfs_super_root(disk_super))
7690                 return 1;
7691
7692         features = btrfs_super_incompat_flags(disk_super);
7693         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
7694                 mixed = 1;
7695
7696         flags = BTRFS_BLOCK_GROUP_SYSTEM;
7697         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7698         if (ret)
7699                 goto out;
7700
7701         if (mixed) {
7702                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
7703                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7704         } else {
7705                 flags = BTRFS_BLOCK_GROUP_METADATA;
7706                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7707                 if (ret)
7708                         goto out;
7709
7710                 flags = BTRFS_BLOCK_GROUP_DATA;
7711                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
7712         }
7713 out:
7714         return ret;
7715 }
7716
7717 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
7718 {
7719         return unpin_extent_range(root, start, end);
7720 }
7721
7722 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
7723                                u64 num_bytes, u64 *actual_bytes)
7724 {
7725         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
7726 }
7727
7728 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
7729 {
7730         struct btrfs_fs_info *fs_info = root->fs_info;
7731         struct btrfs_block_group_cache *cache = NULL;
7732         u64 group_trimmed;
7733         u64 start;
7734         u64 end;
7735         u64 trimmed = 0;
7736         int ret = 0;
7737
7738         cache = btrfs_lookup_block_group(fs_info, range->start);
7739
7740         while (cache) {
7741                 if (cache->key.objectid >= (range->start + range->len)) {
7742                         btrfs_put_block_group(cache);
7743                         break;
7744                 }
7745
7746                 start = max(range->start, cache->key.objectid);
7747                 end = min(range->start + range->len,
7748                                 cache->key.objectid + cache->key.offset);
7749
7750                 if (end - start >= range->minlen) {
7751                         if (!block_group_cache_done(cache)) {
7752                                 ret = cache_block_group(cache, NULL, root, 0);
7753                                 if (!ret)
7754                                         wait_block_group_cache_done(cache);
7755                         }
7756                         ret = btrfs_trim_block_group(cache,
7757                                                      &group_trimmed,
7758                                                      start,
7759                                                      end,
7760                                                      range->minlen);
7761
7762                         trimmed += group_trimmed;
7763                         if (ret) {
7764                                 btrfs_put_block_group(cache);
7765                                 break;
7766                         }
7767                 }
7768
7769                 cache = next_block_group(fs_info->tree_root, cache);
7770         }
7771
7772         range->len = trimmed;
7773         return ret;
7774 }