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/sched/signal.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/writeback.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/sort.h>
  24 #include <linux/rcupdate.h>
  25 #include <linux/kthread.h>
  26 #include <linux/slab.h>
  27 #include <linux/ratelimit.h>
  28 #include <linux/percpu_counter.h>
  29 #include "hash.h"
  30 #include "tree-log.h"
  31 #include "disk-io.h"
  32 #include "print-tree.h"
  33 #include "volumes.h"
  34 #include "raid56.h"
  35 #include "locking.h"
  36 #include "free-space-cache.h"
  37 #include "free-space-tree.h"
  38 #include "math.h"
  39 #include "sysfs.h"
  40 #include "qgroup.h"
  41
  42 #undef SCRAMBLE_DELAYED_REFS
  43
  44 /*
  45  * control flags for do_chunk_alloc's force field
  46  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  47  * if we really need one.
  48  *
  49  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  50  * if we have very few chunks already allocated.  This is
  51  * used as part of the clustering code to help make sure
  52  * we have a good pool of storage to cluster in, without
  53  * filling the FS with empty chunks
  54  *
  55  * CHUNK_ALLOC_FORCE means it must try to allocate one
  56  *
  57  */
  58 enum {
  59         CHUNK_ALLOC_NO_FORCE = 0,
  60         CHUNK_ALLOC_LIMITED = 1,
  61         CHUNK_ALLOC_FORCE = 2,
  62 };
  63
  64 static int update_block_group(struct btrfs_trans_handle *trans,
  65                               struct btrfs_fs_info *fs_info, u64 bytenr,
  66                               u64 num_bytes, int alloc);
  67 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  68                                struct btrfs_fs_info *fs_info,
  69                                 struct btrfs_delayed_ref_node *node, u64 parent,
  70                                 u64 root_objectid, u64 owner_objectid,
  71                                 u64 owner_offset, int refs_to_drop,
  72                                 struct btrfs_delayed_extent_op *extra_op);
  73 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  74                                     struct extent_buffer *leaf,
  75                                     struct btrfs_extent_item *ei);
  76 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  77                                       struct btrfs_fs_info *fs_info,
  78                                       u64 parent, u64 root_objectid,
  79                                       u64 flags, u64 owner, u64 offset,
  80                                       struct btrfs_key *ins, int ref_mod);
  81 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  82                                      struct btrfs_fs_info *fs_info,
  83                                      u64 parent, u64 root_objectid,
  84                                      u64 flags, struct btrfs_disk_key *key,
  85                                      int level, struct btrfs_key *ins);
  86 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  87                           struct btrfs_fs_info *fs_info, u64 flags,
  88                           int force);
  89 static int find_next_key(struct btrfs_path *path, int level,
  90                          struct btrfs_key *key);
  91 static void dump_space_info(struct btrfs_fs_info *fs_info,
  92                             struct btrfs_space_info *info, u64 bytes,
  93                             int dump_block_groups);
  94 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
  95                                     u64 ram_bytes, u64 num_bytes, int delalloc);
  96 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
  97                                      u64 num_bytes, int delalloc);
  98 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
  99                                u64 num_bytes);
 100 static int __reserve_metadata_bytes(struct btrfs_root *root,
 101                                     struct btrfs_space_info *space_info,
 102                                     u64 orig_bytes,
 103                                     enum btrfs_reserve_flush_enum flush);
 104 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
 105                                      struct btrfs_space_info *space_info,
 106                                      u64 num_bytes);
 107 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
 108                                      struct btrfs_space_info *space_info,
 109                                      u64 num_bytes);
 110
 111 static noinline int
 112 block_group_cache_done(struct btrfs_block_group_cache *cache)
 113 {
 114         smp_mb();
 115         return cache->cached == BTRFS_CACHE_FINISHED ||
 116                 cache->cached == BTRFS_CACHE_ERROR;
 117 }
 118
 119 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 120 {
 121         return (cache->flags & bits) == bits;
 122 }
 123
 124 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 125 {
 126         atomic_inc(&cache->count);
 127 }
 128
 129 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 130 {
 131         if (atomic_dec_and_test(&cache->count)) {
 132                 WARN_ON(cache->pinned > 0);
 133                 WARN_ON(cache->reserved > 0);
 134
 135                 /*
 136                  * If not empty, someone is still holding mutex of
 137                  * full_stripe_lock, which can only be released by caller.
 138                  * And it will definitely cause use-after-free when caller
 139                  * tries to release full stripe lock.
 140                  *
 141                  * No better way to resolve, but only to warn.
 142                  */
 143                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 144                 kfree(cache->free_space_ctl);
 145                 kfree(cache);
 146         }
 147 }
 148
 149 /*
 150  * this adds the block group to the fs_info rb tree for the block group
 151  * cache
 152  */
 153 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 154                                 struct btrfs_block_group_cache *block_group)
 155 {
 156         struct rb_node **p;
 157         struct rb_node *parent = NULL;
 158         struct btrfs_block_group_cache *cache;
 159
 160         spin_lock(&info->block_group_cache_lock);
 161         p = &info->block_group_cache_tree.rb_node;
 162
 163         while (*p) {
 164                 parent = *p;
 165                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 166                                  cache_node);
 167                 if (block_group->key.objectid < cache->key.objectid) {
 168                         p = &(*p)->rb_left;
 169                 } else if (block_group->key.objectid > cache->key.objectid) {
 170                         p = &(*p)->rb_right;
 171                 } else {
 172                         spin_unlock(&info->block_group_cache_lock);
 173                         return -EEXIST;
 174                 }
 175         }
 176
 177         rb_link_node(&block_group->cache_node, parent, p);
 178         rb_insert_color(&block_group->cache_node,
 179                         &info->block_group_cache_tree);
 180
 181         if (info->first_logical_byte > block_group->key.objectid)
 182                 info->first_logical_byte = block_group->key.objectid;
 183
 184         spin_unlock(&info->block_group_cache_lock);
 185
 186         return 0;
 187 }
 188
 189 /*
 190  * This will return the block group at or after bytenr if contains is 0, else
 191  * it will return the block group that contains the bytenr
 192  */
 193 static struct btrfs_block_group_cache *
 194 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 195                               int contains)
 196 {
 197         struct btrfs_block_group_cache *cache, *ret = NULL;
 198         struct rb_node *n;
 199         u64 end, start;
 200
 201         spin_lock(&info->block_group_cache_lock);
 202         n = info->block_group_cache_tree.rb_node;
 203
 204         while (n) {
 205                 cache = rb_entry(n, struct btrfs_block_group_cache,
 206                                  cache_node);
 207                 end = cache->key.objectid + cache->key.offset - 1;
 208                 start = cache->key.objectid;
 209
 210                 if (bytenr < start) {
 211                         if (!contains && (!ret || start < ret->key.objectid))
 212                                 ret = cache;
 213                         n = n->rb_left;
 214                 } else if (bytenr > start) {
 215                         if (contains && bytenr <= end) {
 216                                 ret = cache;
 217                                 break;
 218                         }
 219                         n = n->rb_right;
 220                 } else {
 221                         ret = cache;
 222                         break;
 223                 }
 224         }
 225         if (ret) {
 226                 btrfs_get_block_group(ret);
 227                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 228                         info->first_logical_byte = ret->key.objectid;
 229         }
 230         spin_unlock(&info->block_group_cache_lock);
 231
 232         return ret;
 233 }
 234
 235 static int add_excluded_extent(struct btrfs_fs_info *fs_info,
 236                                u64 start, u64 num_bytes)
 237 {
 238         u64 end = start + num_bytes - 1;
 239         set_extent_bits(&fs_info->freed_extents[0],
 240                         start, end, EXTENT_UPTODATE);
 241         set_extent_bits(&fs_info->freed_extents[1],
 242                         start, end, EXTENT_UPTODATE);
 243         return 0;
 244 }
 245
 246 static void free_excluded_extents(struct btrfs_fs_info *fs_info,
 247                                   struct btrfs_block_group_cache *cache)
 248 {
 249         u64 start, end;
 250
 251         start = cache->key.objectid;
 252         end = start + cache->key.offset - 1;
 253
 254         clear_extent_bits(&fs_info->freed_extents[0],
 255                           start, end, EXTENT_UPTODATE);
 256         clear_extent_bits(&fs_info->freed_extents[1],
 257                           start, end, EXTENT_UPTODATE);
 258 }
 259
 260 static int exclude_super_stripes(struct btrfs_fs_info *fs_info,
 261                                  struct btrfs_block_group_cache *cache)
 262 {
 263         u64 bytenr;
 264         u64 *logical;
 265         int stripe_len;
 266         int i, nr, ret;
 267
 268         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 269                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 270                 cache->bytes_super += stripe_len;
 271                 ret = add_excluded_extent(fs_info, cache->key.objectid,
 272                                           stripe_len);
 273                 if (ret)
 274                         return ret;
 275         }
 276
 277         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 278                 bytenr = btrfs_sb_offset(i);
 279                 ret = btrfs_rmap_block(fs_info, cache->key.objectid,
 280                                        bytenr, 0, &logical, &nr, &stripe_len);
 281                 if (ret)
 282                         return ret;
 283
 284                 while (nr--) {
 285                         u64 start, len;
 286
 287                         if (logical[nr] > cache->key.objectid +
 288                             cache->key.offset)
 289                                 continue;
 290
 291                         if (logical[nr] + stripe_len <= cache->key.objectid)
 292                                 continue;
 293
 294                         start = logical[nr];
 295                         if (start < cache->key.objectid) {
 296                                 start = cache->key.objectid;
 297                                 len = (logical[nr] + stripe_len) - start;
 298                         } else {
 299                                 len = min_t(u64, stripe_len,
 300                                             cache->key.objectid +
 301                                             cache->key.offset - start);
 302                         }
 303
 304                         cache->bytes_super += len;
 305                         ret = add_excluded_extent(fs_info, start, len);
 306                         if (ret) {
 307                                 kfree(logical);
 308                                 return ret;
 309                         }
 310                 }
 311
 312                 kfree(logical);
 313         }
 314         return 0;
 315 }
 316
 317 static struct btrfs_caching_control *
 318 get_caching_control(struct btrfs_block_group_cache *cache)
 319 {
 320         struct btrfs_caching_control *ctl;
 321
 322         spin_lock(&cache->lock);
 323         if (!cache->caching_ctl) {
 324                 spin_unlock(&cache->lock);
 325                 return NULL;
 326         }
 327
 328         ctl = cache->caching_ctl;
 329         refcount_inc(&ctl->count);
 330         spin_unlock(&cache->lock);
 331         return ctl;
 332 }
 333
 334 static void put_caching_control(struct btrfs_caching_control *ctl)
 335 {
 336         if (refcount_dec_and_test(&ctl->count))
 337                 kfree(ctl);
 338 }
 339
 340 #ifdef CONFIG_BTRFS_DEBUG
 341 static void fragment_free_space(struct btrfs_block_group_cache *block_group)
 342 {
 343         struct btrfs_fs_info *fs_info = block_group->fs_info;
 344         u64 start = block_group->key.objectid;
 345         u64 len = block_group->key.offset;
 346         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 347                 fs_info->nodesize : fs_info->sectorsize;
 348         u64 step = chunk << 1;
 349
 350         while (len > chunk) {
 351                 btrfs_remove_free_space(block_group, start, chunk);
 352                 start += step;
 353                 if (len < step)
 354                         len = 0;
 355                 else
 356                         len -= step;
 357         }
 358 }
 359 #endif
 360
 361 /*
 362  * this is only called by cache_block_group, since we could have freed extents
 363  * we need to check the pinned_extents for any extents that can't be used yet
 364  * since their free space will be released as soon as the transaction commits.
 365  */
 366 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 367                        struct btrfs_fs_info *info, u64 start, u64 end)
 368 {
 369         u64 extent_start, extent_end, size, total_added = 0;
 370         int ret;
 371
 372         while (start < end) {
 373                 ret = find_first_extent_bit(info->pinned_extents, start,
 374                                             &extent_start, &extent_end,
 375                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 376                                             NULL);
 377                 if (ret)
 378                         break;
 379
 380                 if (extent_start <= start) {
 381                         start = extent_end + 1;
 382                 } else if (extent_start > start && extent_start < end) {
 383                         size = extent_start - start;
 384                         total_added += size;
 385                         ret = btrfs_add_free_space(block_group, start,
 386                                                    size);
 387                         BUG_ON(ret); /* -ENOMEM or logic error */
 388                         start = extent_end + 1;
 389                 } else {
 390                         break;
 391                 }
 392         }
 393
 394         if (start < end) {
 395                 size = end - start;
 396                 total_added += size;
 397                 ret = btrfs_add_free_space(block_group, start, size);
 398                 BUG_ON(ret); /* -ENOMEM or logic error */
 399         }
 400
 401         return total_added;
 402 }
 403
 404 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 405 {
 406         struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
 407         struct btrfs_fs_info *fs_info = block_group->fs_info;
 408         struct btrfs_root *extent_root = fs_info->extent_root;
 409         struct btrfs_path *path;
 410         struct extent_buffer *leaf;
 411         struct btrfs_key key;
 412         u64 total_found = 0;
 413         u64 last = 0;
 414         u32 nritems;
 415         int ret;
 416         bool wakeup = true;
 417
 418         path = btrfs_alloc_path();
 419         if (!path)
 420                 return -ENOMEM;
 421
 422         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 423
 424 #ifdef CONFIG_BTRFS_DEBUG
 425         /*
 426          * If we're fragmenting we don't want to make anybody think we can
 427          * allocate from this block group until we've had a chance to fragment
 428          * the free space.
 429          */
 430         if (btrfs_should_fragment_free_space(block_group))
 431                 wakeup = false;
 432 #endif
 433         /*
 434          * We don't want to deadlock with somebody trying to allocate a new
 435          * extent for the extent root while also trying to search the extent
 436          * root to add free space.  So we skip locking and search the commit
 437          * root, since its read-only
 438          */
 439         path->skip_locking = 1;
 440         path->search_commit_root = 1;
 441         path->reada = READA_FORWARD;
 442
 443         key.objectid = last;
 444         key.offset = 0;
 445         key.type = BTRFS_EXTENT_ITEM_KEY;
 446
 447 next:
 448         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 449         if (ret < 0)
 450                 goto out;
 451
 452         leaf = path->nodes[0];
 453         nritems = btrfs_header_nritems(leaf);
 454
 455         while (1) {
 456                 if (btrfs_fs_closing(fs_info) > 1) {
 457                         last = (u64)-1;
 458                         break;
 459                 }
 460
 461                 if (path->slots[0] < nritems) {
 462                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 463                 } else {
 464                         ret = find_next_key(path, 0, &key);
 465                         if (ret)
 466                                 break;
 467
 468                         if (need_resched() ||
 469                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 470                                 if (wakeup)
 471                                         caching_ctl->progress = last;
 472                                 btrfs_release_path(path);
 473                                 up_read(&fs_info->commit_root_sem);
 474                                 mutex_unlock(&caching_ctl->mutex);
 475                                 cond_resched();
 476                                 mutex_lock(&caching_ctl->mutex);
 477                                 down_read(&fs_info->commit_root_sem);
 478                                 goto next;
 479                         }
 480
 481                         ret = btrfs_next_leaf(extent_root, path);
 482                         if (ret < 0)
 483                                 goto out;
 484                         if (ret)
 485                                 break;
 486                         leaf = path->nodes[0];
 487                         nritems = btrfs_header_nritems(leaf);
 488                         continue;
 489                 }
 490
 491                 if (key.objectid < last) {
 492                         key.objectid = last;
 493                         key.offset = 0;
 494                         key.type = BTRFS_EXTENT_ITEM_KEY;
 495
 496                         if (wakeup)
 497                                 caching_ctl->progress = last;
 498                         btrfs_release_path(path);
 499                         goto next;
 500                 }
 501
 502                 if (key.objectid < block_group->key.objectid) {
 503                         path->slots[0]++;
 504                         continue;
 505                 }
 506
 507                 if (key.objectid >= block_group->key.objectid +
 508                     block_group->key.offset)
 509                         break;
 510
 511                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 512                     key.type == BTRFS_METADATA_ITEM_KEY) {
 513                         total_found += add_new_free_space(block_group,
 514                                                           fs_info, last,
 515                                                           key.objectid);
 516                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 517                                 last = key.objectid +
 518                                         fs_info->nodesize;
 519                         else
 520                                 last = key.objectid + key.offset;
 521
 522                         if (total_found > CACHING_CTL_WAKE_UP) {
 523                                 total_found = 0;
 524                                 if (wakeup)
 525                                         wake_up(&caching_ctl->wait);
 526                         }
 527                 }
 528                 path->slots[0]++;
 529         }
 530         ret = 0;
 531
 532         total_found += add_new_free_space(block_group, fs_info, last,
 533                                           block_group->key.objectid +
 534                                           block_group->key.offset);
 535         caching_ctl->progress = (u64)-1;
 536
 537 out:
 538         btrfs_free_path(path);
 539         return ret;
 540 }
 541
 542 static noinline void caching_thread(struct btrfs_work *work)
 543 {
 544         struct btrfs_block_group_cache *block_group;
 545         struct btrfs_fs_info *fs_info;
 546         struct btrfs_caching_control *caching_ctl;
 547         struct btrfs_root *extent_root;
 548         int ret;
 549
 550         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 551         block_group = caching_ctl->block_group;
 552         fs_info = block_group->fs_info;
 553         extent_root = fs_info->extent_root;
 554
 555         mutex_lock(&caching_ctl->mutex);
 556         down_read(&fs_info->commit_root_sem);
 557
 558         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 559                 ret = load_free_space_tree(caching_ctl);
 560         else
 561                 ret = load_extent_tree_free(caching_ctl);
 562
 563         spin_lock(&block_group->lock);
 564         block_group->caching_ctl = NULL;
 565         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 566         spin_unlock(&block_group->lock);
 567
 568 #ifdef CONFIG_BTRFS_DEBUG
 569         if (btrfs_should_fragment_free_space(block_group)) {
 570                 u64 bytes_used;
 571
 572                 spin_lock(&block_group->space_info->lock);
 573                 spin_lock(&block_group->lock);
 574                 bytes_used = block_group->key.offset -
 575                         btrfs_block_group_used(&block_group->item);
 576                 block_group->space_info->bytes_used += bytes_used >> 1;
 577                 spin_unlock(&block_group->lock);
 578                 spin_unlock(&block_group->space_info->lock);
 579                 fragment_free_space(block_group);
 580         }
 581 #endif
 582
 583         caching_ctl->progress = (u64)-1;
 584
 585         up_read(&fs_info->commit_root_sem);
 586         free_excluded_extents(fs_info, block_group);
 587         mutex_unlock(&caching_ctl->mutex);
 588
 589         wake_up(&caching_ctl->wait);
 590
 591         put_caching_control(caching_ctl);
 592         btrfs_put_block_group(block_group);
 593 }
 594
 595 static int cache_block_group(struct btrfs_block_group_cache *cache,
 596                              int load_cache_only)
 597 {
 598         DEFINE_WAIT(wait);
 599         struct btrfs_fs_info *fs_info = cache->fs_info;
 600         struct btrfs_caching_control *caching_ctl;
 601         int ret = 0;
 602
 603         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 604         if (!caching_ctl)
 605                 return -ENOMEM;
 606
 607         INIT_LIST_HEAD(&caching_ctl->list);
 608         mutex_init(&caching_ctl->mutex);
 609         init_waitqueue_head(&caching_ctl->wait);
 610         caching_ctl->block_group = cache;
 611         caching_ctl->progress = cache->key.objectid;
 612         refcount_set(&caching_ctl->count, 1);
 613         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 614                         caching_thread, NULL, NULL);
 615
 616         spin_lock(&cache->lock);
 617         /*
 618          * This should be a rare occasion, but this could happen I think in the
 619          * case where one thread starts to load the space cache info, and then
 620          * some other thread starts a transaction commit which tries to do an
 621          * allocation while the other thread is still loading the space cache
 622          * info.  The previous loop should have kept us from choosing this block
 623          * group, but if we've moved to the state where we will wait on caching
 624          * block groups we need to first check if we're doing a fast load here,
 625          * so we can wait for it to finish, otherwise we could end up allocating
 626          * from a block group who's cache gets evicted for one reason or
 627          * another.
 628          */
 629         while (cache->cached == BTRFS_CACHE_FAST) {
 630                 struct btrfs_caching_control *ctl;
 631
 632                 ctl = cache->caching_ctl;
 633                 refcount_inc(&ctl->count);
 634                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 635                 spin_unlock(&cache->lock);
 636
 637                 schedule();
 638
 639                 finish_wait(&ctl->wait, &wait);
 640                 put_caching_control(ctl);
 641                 spin_lock(&cache->lock);
 642         }
 643
 644         if (cache->cached != BTRFS_CACHE_NO) {
 645                 spin_unlock(&cache->lock);
 646                 kfree(caching_ctl);
 647                 return 0;
 648         }
 649         WARN_ON(cache->caching_ctl);
 650         cache->caching_ctl = caching_ctl;
 651         cache->cached = BTRFS_CACHE_FAST;
 652         spin_unlock(&cache->lock);
 653
 654         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 655                 mutex_lock(&caching_ctl->mutex);
 656                 ret = load_free_space_cache(fs_info, cache);
 657
 658                 spin_lock(&cache->lock);
 659                 if (ret == 1) {
 660                         cache->caching_ctl = NULL;
 661                         cache->cached = BTRFS_CACHE_FINISHED;
 662                         cache->last_byte_to_unpin = (u64)-1;
 663                         caching_ctl->progress = (u64)-1;
 664                 } else {
 665                         if (load_cache_only) {
 666                                 cache->caching_ctl = NULL;
 667                                 cache->cached = BTRFS_CACHE_NO;
 668                         } else {
 669                                 cache->cached = BTRFS_CACHE_STARTED;
 670                                 cache->has_caching_ctl = 1;
 671                         }
 672                 }
 673                 spin_unlock(&cache->lock);
 674 #ifdef CONFIG_BTRFS_DEBUG
 675                 if (ret == 1 &&
 676                     btrfs_should_fragment_free_space(cache)) {
 677                         u64 bytes_used;
 678
 679                         spin_lock(&cache->space_info->lock);
 680                         spin_lock(&cache->lock);
 681                         bytes_used = cache->key.offset -
 682                                 btrfs_block_group_used(&cache->item);
 683                         cache->space_info->bytes_used += bytes_used >> 1;
 684                         spin_unlock(&cache->lock);
 685                         spin_unlock(&cache->space_info->lock);
 686                         fragment_free_space(cache);
 687                 }
 688 #endif
 689                 mutex_unlock(&caching_ctl->mutex);
 690
 691                 wake_up(&caching_ctl->wait);
 692                 if (ret == 1) {
 693                         put_caching_control(caching_ctl);
 694                         free_excluded_extents(fs_info, cache);
 695                         return 0;
 696                 }
 697         } else {
 698                 /*
 699                  * We're either using the free space tree or no caching at all.
 700                  * Set cached to the appropriate value and wakeup any waiters.
 701                  */
 702                 spin_lock(&cache->lock);
 703                 if (load_cache_only) {
 704                         cache->caching_ctl = NULL;
 705                         cache->cached = BTRFS_CACHE_NO;
 706                 } else {
 707                         cache->cached = BTRFS_CACHE_STARTED;
 708                         cache->has_caching_ctl = 1;
 709                 }
 710                 spin_unlock(&cache->lock);
 711                 wake_up(&caching_ctl->wait);
 712         }
 713
 714         if (load_cache_only) {
 715                 put_caching_control(caching_ctl);
 716                 return 0;
 717         }
 718
 719         down_write(&fs_info->commit_root_sem);
 720         refcount_inc(&caching_ctl->count);
 721         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 722         up_write(&fs_info->commit_root_sem);
 723
 724         btrfs_get_block_group(cache);
 725
 726         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 727
 728         return ret;
 729 }
 730
 731 /*
 732  * return the block group that starts at or after bytenr
 733  */
 734 static struct btrfs_block_group_cache *
 735 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 736 {
 737         return block_group_cache_tree_search(info, bytenr, 0);
 738 }
 739
 740 /*
 741  * return the block group that contains the given bytenr
 742  */
 743 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 744                                                  struct btrfs_fs_info *info,
 745                                                  u64 bytenr)
 746 {
 747         return block_group_cache_tree_search(info, bytenr, 1);
 748 }
 749
 750 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 751                                                   u64 flags)
 752 {
 753         struct list_head *head = &info->space_info;
 754         struct btrfs_space_info *found;
 755
 756         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 757
 758         rcu_read_lock();
 759         list_for_each_entry_rcu(found, head, list) {
 760                 if (found->flags & flags) {
 761                         rcu_read_unlock();
 762                         return found;
 763                 }
 764         }
 765         rcu_read_unlock();
 766         return NULL;
 767 }
 768
 769 /*
 770  * after adding space to the filesystem, we need to clear the full flags
 771  * on all the space infos.
 772  */
 773 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 774 {
 775         struct list_head *head = &info->space_info;
 776         struct btrfs_space_info *found;
 777
 778         rcu_read_lock();
 779         list_for_each_entry_rcu(found, head, list)
 780                 found->full = 0;
 781         rcu_read_unlock();
 782 }
 783
 784 /* simple helper to search for an existing data extent at a given offset */
 785 int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
 786 {
 787         int ret;
 788         struct btrfs_key key;
 789         struct btrfs_path *path;
 790
 791         path = btrfs_alloc_path();
 792         if (!path)
 793                 return -ENOMEM;
 794
 795         key.objectid = start;
 796         key.offset = len;
 797         key.type = BTRFS_EXTENT_ITEM_KEY;
 798         ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 799         btrfs_free_path(path);
 800         return ret;
 801 }
 802
 803 /*
 804  * helper function to lookup reference count and flags of a tree block.
 805  *
 806  * the head node for delayed ref is used to store the sum of all the
 807  * reference count modifications queued up in the rbtree. the head
 808  * node may also store the extent flags to set. This way you can check
 809  * to see what the reference count and extent flags would be if all of
 810  * the delayed refs are not processed.
 811  */
 812 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 813                              struct btrfs_fs_info *fs_info, u64 bytenr,
 814                              u64 offset, int metadata, u64 *refs, u64 *flags)
 815 {
 816         struct btrfs_delayed_ref_head *head;
 817         struct btrfs_delayed_ref_root *delayed_refs;
 818         struct btrfs_path *path;
 819         struct btrfs_extent_item *ei;
 820         struct extent_buffer *leaf;
 821         struct btrfs_key key;
 822         u32 item_size;
 823         u64 num_refs;
 824         u64 extent_flags;
 825         int ret;
 826
 827         /*
 828          * If we don't have skinny metadata, don't bother doing anything
 829          * different
 830          */
 831         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 832                 offset = fs_info->nodesize;
 833                 metadata = 0;
 834         }
 835
 836         path = btrfs_alloc_path();
 837         if (!path)
 838                 return -ENOMEM;
 839
 840         if (!trans) {
 841                 path->skip_locking = 1;
 842                 path->search_commit_root = 1;
 843         }
 844
 845 search_again:
 846         key.objectid = bytenr;
 847         key.offset = offset;
 848         if (metadata)
 849                 key.type = BTRFS_METADATA_ITEM_KEY;
 850         else
 851                 key.type = BTRFS_EXTENT_ITEM_KEY;
 852
 853         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 854         if (ret < 0)
 855                 goto out_free;
 856
 857         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 858                 if (path->slots[0]) {
 859                         path->slots[0]--;
 860                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 861                                               path->slots[0]);
 862                         if (key.objectid == bytenr &&
 863                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 864                             key.offset == fs_info->nodesize)
 865                                 ret = 0;
 866                 }
 867         }
 868
 869         if (ret == 0) {
 870                 leaf = path->nodes[0];
 871                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 872                 if (item_size >= sizeof(*ei)) {
 873                         ei = btrfs_item_ptr(leaf, path->slots[0],
 874                                             struct btrfs_extent_item);
 875                         num_refs = btrfs_extent_refs(leaf, ei);
 876                         extent_flags = btrfs_extent_flags(leaf, ei);
 877                 } else {
 878 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 879                         struct btrfs_extent_item_v0 *ei0;
 880                         BUG_ON(item_size != sizeof(*ei0));
 881                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 882                                              struct btrfs_extent_item_v0);
 883                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 884                         /* FIXME: this isn't correct for data */
 885                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 886 #else
 887                         BUG();
 888 #endif
 889                 }
 890                 BUG_ON(num_refs == 0);
 891         } else {
 892                 num_refs = 0;
 893                 extent_flags = 0;
 894                 ret = 0;
 895         }
 896
 897         if (!trans)
 898                 goto out;
 899
 900         delayed_refs = &trans->transaction->delayed_refs;
 901         spin_lock(&delayed_refs->lock);
 902         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 903         if (head) {
 904                 if (!mutex_trylock(&head->mutex)) {
 905                         refcount_inc(&head->node.refs);
 906                         spin_unlock(&delayed_refs->lock);
 907
 908                         btrfs_release_path(path);
 909
 910                         /*
 911                          * Mutex was contended, block until it's released and try
 912                          * again
 913                          */
 914                         mutex_lock(&head->mutex);
 915                         mutex_unlock(&head->mutex);
 916                         btrfs_put_delayed_ref(&head->node);
 917                         goto search_again;
 918                 }
 919                 spin_lock(&head->lock);
 920                 if (head->extent_op && head->extent_op->update_flags)
 921                         extent_flags |= head->extent_op->flags_to_set;
 922                 else
 923                         BUG_ON(num_refs == 0);
 924
 925                 num_refs += head->node.ref_mod;
 926                 spin_unlock(&head->lock);
 927                 mutex_unlock(&head->mutex);
 928         }
 929         spin_unlock(&delayed_refs->lock);
 930 out:
 931         WARN_ON(num_refs == 0);
 932         if (refs)
 933                 *refs = num_refs;
 934         if (flags)
 935                 *flags = extent_flags;
 936 out_free:
 937         btrfs_free_path(path);
 938         return ret;
 939 }
 940
 941 /*
 942  * Back reference rules.  Back refs have three main goals:
 943  *
 944  * 1) differentiate between all holders of references to an extent so that
 945  *    when a reference is dropped we can make sure it was a valid reference
 946  *    before freeing the extent.
 947  *
 948  * 2) Provide enough information to quickly find the holders of an extent
 949  *    if we notice a given block is corrupted or bad.
 950  *
 951  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 952  *    maintenance.  This is actually the same as #2, but with a slightly
 953  *    different use case.
 954  *
 955  * There are two kinds of back refs. The implicit back refs is optimized
 956  * for pointers in non-shared tree blocks. For a given pointer in a block,
 957  * back refs of this kind provide information about the block's owner tree
 958  * and the pointer's key. These information allow us to find the block by
 959  * b-tree searching. The full back refs is for pointers in tree blocks not
 960  * referenced by their owner trees. The location of tree block is recorded
 961  * in the back refs. Actually the full back refs is generic, and can be
 962  * used in all cases the implicit back refs is used. The major shortcoming
 963  * of the full back refs is its overhead. Every time a tree block gets
 964  * COWed, we have to update back refs entry for all pointers in it.
 965  *
 966  * For a newly allocated tree block, we use implicit back refs for
 967  * pointers in it. This means most tree related operations only involve
 968  * implicit back refs. For a tree block created in old transaction, the
 969  * only way to drop a reference to it is COW it. So we can detect the
 970  * event that tree block loses its owner tree's reference and do the
 971  * back refs conversion.
 972  *
 973  * When a tree block is COWed through a tree, there are four cases:
 974  *
 975  * The reference count of the block is one and the tree is the block's
 976  * owner tree. Nothing to do in this case.
 977  *
 978  * The reference count of the block is one and the tree is not the
 979  * block's owner tree. In this case, full back refs is used for pointers
 980  * in the block. Remove these full back refs, add implicit back refs for
 981  * every pointers in the new block.
 982  *
 983  * The reference count of the block is greater than one and the tree is
 984  * the block's owner tree. In this case, implicit back refs is used for
 985  * pointers in the block. Add full back refs for every pointers in the
 986  * block, increase lower level extents' reference counts. The original
 987  * implicit back refs are entailed to the new block.
 988  *
 989  * The reference count of the block is greater than one and the tree is
 990  * not the block's owner tree. Add implicit back refs for every pointer in
 991  * the new block, increase lower level extents' reference count.
 992  *
 993  * Back Reference Key composing:
 994  *
 995  * The key objectid corresponds to the first byte in the extent,
 996  * The key type is used to differentiate between types of back refs.
 997  * There are different meanings of the key offset for different types
 998  * of back refs.
 999  *
1000  * File extents can be referenced by:
1001  *
1002  * - multiple snapshots, subvolumes, or different generations in one subvol
1003  * - different files inside a single subvolume
1004  * - different offsets inside a file (bookend extents in file.c)
1005  *
1006  * The extent ref structure for the implicit back refs has fields for:
1007  *
1008  * - Objectid of the subvolume root
1009  * - objectid of the file holding the reference
1010  * - original offset in the file
1011  * - how many bookend extents
1012  *
1013  * The key offset for the implicit back refs is hash of the first
1014  * three fields.
1015  *
1016  * The extent ref structure for the full back refs has field for:
1017  *
1018  * - number of pointers in the tree leaf
1019  *
1020  * The key offset for the implicit back refs is the first byte of
1021  * the tree leaf
1022  *
1023  * When a file extent is allocated, The implicit back refs is used.
1024  * the fields are filled in:
1025  *
1026  *     (root_key.objectid, inode objectid, offset in file, 1)
1027  *
1028  * When a file extent is removed file truncation, we find the
1029  * corresponding implicit back refs and check the following fields:
1030  *
1031  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1032  *
1033  * Btree extents can be referenced by:
1034  *
1035  * - Different subvolumes
1036  *
1037  * Both the implicit back refs and the full back refs for tree blocks
1038  * only consist of key. The key offset for the implicit back refs is
1039  * objectid of block's owner tree. The key offset for the full back refs
1040  * is the first byte of parent block.
1041  *
1042  * When implicit back refs is used, information about the lowest key and
1043  * level of the tree block are required. These information are stored in
1044  * tree block info structure.
1045  */
1046
1047 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1048 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1049                                   struct btrfs_fs_info *fs_info,
1050                                   struct btrfs_path *path,
1051                                   u64 owner, u32 extra_size)
1052 {
1053         struct btrfs_root *root = fs_info->extent_root;
1054         struct btrfs_extent_item *item;
1055         struct btrfs_extent_item_v0 *ei0;
1056         struct btrfs_extent_ref_v0 *ref0;
1057         struct btrfs_tree_block_info *bi;
1058         struct extent_buffer *leaf;
1059         struct btrfs_key key;
1060         struct btrfs_key found_key;
1061         u32 new_size = sizeof(*item);
1062         u64 refs;
1063         int ret;
1064
1065         leaf = path->nodes[0];
1066         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1067
1068         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1069         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1070                              struct btrfs_extent_item_v0);
1071         refs = btrfs_extent_refs_v0(leaf, ei0);
1072
1073         if (owner == (u64)-1) {
1074                 while (1) {
1075                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1076                                 ret = btrfs_next_leaf(root, path);
1077                                 if (ret < 0)
1078                                         return ret;
1079                                 BUG_ON(ret > 0); /* Corruption */
1080                                 leaf = path->nodes[0];
1081                         }
1082                         btrfs_item_key_to_cpu(leaf, &found_key,
1083                                               path->slots[0]);
1084                         BUG_ON(key.objectid != found_key.objectid);
1085                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1086                                 path->slots[0]++;
1087                                 continue;
1088                         }
1089                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1090                                               struct btrfs_extent_ref_v0);
1091                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1092                         break;
1093                 }
1094         }
1095         btrfs_release_path(path);
1096
1097         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1098                 new_size += sizeof(*bi);
1099
1100         new_size -= sizeof(*ei0);
1101         ret = btrfs_search_slot(trans, root, &key, path,
1102                                 new_size + extra_size, 1);
1103         if (ret < 0)
1104                 return ret;
1105         BUG_ON(ret); /* Corruption */
1106
1107         btrfs_extend_item(fs_info, path, new_size);
1108
1109         leaf = path->nodes[0];
1110         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1111         btrfs_set_extent_refs(leaf, item, refs);
1112         /* FIXME: get real generation */
1113         btrfs_set_extent_generation(leaf, item, 0);
1114         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1115                 btrfs_set_extent_flags(leaf, item,
1116                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1117                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1118                 bi = (struct btrfs_tree_block_info *)(item + 1);
1119                 /* FIXME: get first key of the block */
1120                 memzero_extent_buffer(leaf, (unsigned long)bi, sizeof(*bi));
1121                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1122         } else {
1123                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1124         }
1125         btrfs_mark_buffer_dirty(leaf);
1126         return 0;
1127 }
1128 #endif
1129
1130 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1131 {
1132         u32 high_crc = ~(u32)0;
1133         u32 low_crc = ~(u32)0;
1134         __le64 lenum;
1135
1136         lenum = cpu_to_le64(root_objectid);
1137         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1138         lenum = cpu_to_le64(owner);
1139         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1140         lenum = cpu_to_le64(offset);
1141         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1142
1143         return ((u64)high_crc << 31) ^ (u64)low_crc;
1144 }
1145
1146 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1147                                      struct btrfs_extent_data_ref *ref)
1148 {
1149         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1150                                     btrfs_extent_data_ref_objectid(leaf, ref),
1151                                     btrfs_extent_data_ref_offset(leaf, ref));
1152 }
1153
1154 static int match_extent_data_ref(struct extent_buffer *leaf,
1155                                  struct btrfs_extent_data_ref *ref,
1156                                  u64 root_objectid, u64 owner, u64 offset)
1157 {
1158         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1159             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1160             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1161                 return 0;
1162         return 1;
1163 }
1164
1165 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1166                                            struct btrfs_fs_info *fs_info,
1167                                            struct btrfs_path *path,
1168                                            u64 bytenr, u64 parent,
1169                                            u64 root_objectid,
1170                                            u64 owner, u64 offset)
1171 {
1172         struct btrfs_root *root = fs_info->extent_root;
1173         struct btrfs_key key;
1174         struct btrfs_extent_data_ref *ref;
1175         struct extent_buffer *leaf;
1176         u32 nritems;
1177         int ret;
1178         int recow;
1179         int err = -ENOENT;
1180
1181         key.objectid = bytenr;
1182         if (parent) {
1183                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1184                 key.offset = parent;
1185         } else {
1186                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1187                 key.offset = hash_extent_data_ref(root_objectid,
1188                                                   owner, offset);
1189         }
1190 again:
1191         recow = 0;
1192         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1193         if (ret < 0) {
1194                 err = ret;
1195                 goto fail;
1196         }
1197
1198         if (parent) {
1199                 if (!ret)
1200                         return 0;
1201 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1202                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1203                 btrfs_release_path(path);
1204                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1205                 if (ret < 0) {
1206                         err = ret;
1207                         goto fail;
1208                 }
1209                 if (!ret)
1210                         return 0;
1211 #endif
1212                 goto fail;
1213         }
1214
1215         leaf = path->nodes[0];
1216         nritems = btrfs_header_nritems(leaf);
1217         while (1) {
1218                 if (path->slots[0] >= nritems) {
1219                         ret = btrfs_next_leaf(root, path);
1220                         if (ret < 0)
1221                                 err = ret;
1222                         if (ret)
1223                                 goto fail;
1224
1225                         leaf = path->nodes[0];
1226                         nritems = btrfs_header_nritems(leaf);
1227                         recow = 1;
1228                 }
1229
1230                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1231                 if (key.objectid != bytenr ||
1232                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1233                         goto fail;
1234
1235                 ref = btrfs_item_ptr(leaf, path->slots[0],
1236                                      struct btrfs_extent_data_ref);
1237
1238                 if (match_extent_data_ref(leaf, ref, root_objectid,
1239                                           owner, offset)) {
1240                         if (recow) {
1241                                 btrfs_release_path(path);
1242                                 goto again;
1243                         }
1244                         err = 0;
1245                         break;
1246                 }
1247                 path->slots[0]++;
1248         }
1249 fail:
1250         return err;
1251 }
1252
1253 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1254                                            struct btrfs_fs_info *fs_info,
1255                                            struct btrfs_path *path,
1256                                            u64 bytenr, u64 parent,
1257                                            u64 root_objectid, u64 owner,
1258                                            u64 offset, int refs_to_add)
1259 {
1260         struct btrfs_root *root = fs_info->extent_root;
1261         struct btrfs_key key;
1262         struct extent_buffer *leaf;
1263         u32 size;
1264         u32 num_refs;
1265         int ret;
1266
1267         key.objectid = bytenr;
1268         if (parent) {
1269                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1270                 key.offset = parent;
1271                 size = sizeof(struct btrfs_shared_data_ref);
1272         } else {
1273                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1274                 key.offset = hash_extent_data_ref(root_objectid,
1275                                                   owner, offset);
1276                 size = sizeof(struct btrfs_extent_data_ref);
1277         }
1278
1279         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1280         if (ret && ret != -EEXIST)
1281                 goto fail;
1282
1283         leaf = path->nodes[0];
1284         if (parent) {
1285                 struct btrfs_shared_data_ref *ref;
1286                 ref = btrfs_item_ptr(leaf, path->slots[0],
1287                                      struct btrfs_shared_data_ref);
1288                 if (ret == 0) {
1289                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1290                 } else {
1291                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1292                         num_refs += refs_to_add;
1293                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1294                 }
1295         } else {
1296                 struct btrfs_extent_data_ref *ref;
1297                 while (ret == -EEXIST) {
1298                         ref = btrfs_item_ptr(leaf, path->slots[0],
1299                                              struct btrfs_extent_data_ref);
1300                         if (match_extent_data_ref(leaf, ref, root_objectid,
1301                                                   owner, offset))
1302                                 break;
1303                         btrfs_release_path(path);
1304                         key.offset++;
1305                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1306                                                       size);
1307                         if (ret && ret != -EEXIST)
1308                                 goto fail;
1309
1310                         leaf = path->nodes[0];
1311                 }
1312                 ref = btrfs_item_ptr(leaf, path->slots[0],
1313                                      struct btrfs_extent_data_ref);
1314                 if (ret == 0) {
1315                         btrfs_set_extent_data_ref_root(leaf, ref,
1316                                                        root_objectid);
1317                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1318                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1319                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1320                 } else {
1321                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1322                         num_refs += refs_to_add;
1323                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1324                 }
1325         }
1326         btrfs_mark_buffer_dirty(leaf);
1327         ret = 0;
1328 fail:
1329         btrfs_release_path(path);
1330         return ret;
1331 }
1332
1333 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1334                                            struct btrfs_fs_info *fs_info,
1335                                            struct btrfs_path *path,
1336                                            int refs_to_drop, int *last_ref)
1337 {
1338         struct btrfs_key key;
1339         struct btrfs_extent_data_ref *ref1 = NULL;
1340         struct btrfs_shared_data_ref *ref2 = NULL;
1341         struct extent_buffer *leaf;
1342         u32 num_refs = 0;
1343         int ret = 0;
1344
1345         leaf = path->nodes[0];
1346         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1347
1348         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1349                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1350                                       struct btrfs_extent_data_ref);
1351                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1352         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1353                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1354                                       struct btrfs_shared_data_ref);
1355                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1356 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1357         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1358                 struct btrfs_extent_ref_v0 *ref0;
1359                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1360                                       struct btrfs_extent_ref_v0);
1361                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1362 #endif
1363         } else {
1364                 BUG();
1365         }
1366
1367         BUG_ON(num_refs < refs_to_drop);
1368         num_refs -= refs_to_drop;
1369
1370         if (num_refs == 0) {
1371                 ret = btrfs_del_item(trans, fs_info->extent_root, path);
1372                 *last_ref = 1;
1373         } else {
1374                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1375                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1376                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1377                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1378 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1379                 else {
1380                         struct btrfs_extent_ref_v0 *ref0;
1381                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1382                                         struct btrfs_extent_ref_v0);
1383                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1384                 }
1385 #endif
1386                 btrfs_mark_buffer_dirty(leaf);
1387         }
1388         return ret;
1389 }
1390
1391 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1392                                           struct btrfs_extent_inline_ref *iref)
1393 {
1394         struct btrfs_key key;
1395         struct extent_buffer *leaf;
1396         struct btrfs_extent_data_ref *ref1;
1397         struct btrfs_shared_data_ref *ref2;
1398         u32 num_refs = 0;
1399
1400         leaf = path->nodes[0];
1401         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1402         if (iref) {
1403                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1404                     BTRFS_EXTENT_DATA_REF_KEY) {
1405                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1406                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1407                 } else {
1408                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1409                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1410                 }
1411         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1412                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1413                                       struct btrfs_extent_data_ref);
1414                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1415         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1416                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1417                                       struct btrfs_shared_data_ref);
1418                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1419 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1420         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1421                 struct btrfs_extent_ref_v0 *ref0;
1422                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1423                                       struct btrfs_extent_ref_v0);
1424                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1425 #endif
1426         } else {
1427                 WARN_ON(1);
1428         }
1429         return num_refs;
1430 }
1431
1432 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1433                                           struct btrfs_fs_info *fs_info,
1434                                           struct btrfs_path *path,
1435                                           u64 bytenr, u64 parent,
1436                                           u64 root_objectid)
1437 {
1438         struct btrfs_root *root = fs_info->extent_root;
1439         struct btrfs_key key;
1440         int ret;
1441
1442         key.objectid = bytenr;
1443         if (parent) {
1444                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1445                 key.offset = parent;
1446         } else {
1447                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1448                 key.offset = root_objectid;
1449         }
1450
1451         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1452         if (ret > 0)
1453                 ret = -ENOENT;
1454 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1455         if (ret == -ENOENT && parent) {
1456                 btrfs_release_path(path);
1457                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1458                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1459                 if (ret > 0)
1460                         ret = -ENOENT;
1461         }
1462 #endif
1463         return ret;
1464 }
1465
1466 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1467                                           struct btrfs_fs_info *fs_info,
1468                                           struct btrfs_path *path,
1469                                           u64 bytenr, u64 parent,
1470                                           u64 root_objectid)
1471 {
1472         struct btrfs_key key;
1473         int ret;
1474
1475         key.objectid = bytenr;
1476         if (parent) {
1477                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1478                 key.offset = parent;
1479         } else {
1480                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1481                 key.offset = root_objectid;
1482         }
1483
1484         ret = btrfs_insert_empty_item(trans, fs_info->extent_root,
1485                                       path, &key, 0);
1486         btrfs_release_path(path);
1487         return ret;
1488 }
1489
1490 static inline int extent_ref_type(u64 parent, u64 owner)
1491 {
1492         int type;
1493         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1494                 if (parent > 0)
1495                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1496                 else
1497                         type = BTRFS_TREE_BLOCK_REF_KEY;
1498         } else {
1499                 if (parent > 0)
1500                         type = BTRFS_SHARED_DATA_REF_KEY;
1501                 else
1502                         type = BTRFS_EXTENT_DATA_REF_KEY;
1503         }
1504         return type;
1505 }
1506
1507 static int find_next_key(struct btrfs_path *path, int level,
1508                          struct btrfs_key *key)
1509
1510 {
1511         for (; level < BTRFS_MAX_LEVEL; level++) {
1512                 if (!path->nodes[level])
1513                         break;
1514                 if (path->slots[level] + 1 >=
1515                     btrfs_header_nritems(path->nodes[level]))
1516                         continue;
1517                 if (level == 0)
1518                         btrfs_item_key_to_cpu(path->nodes[level], key,
1519                                               path->slots[level] + 1);
1520                 else
1521                         btrfs_node_key_to_cpu(path->nodes[level], key,
1522                                               path->slots[level] + 1);
1523                 return 0;
1524         }
1525         return 1;
1526 }
1527
1528 /*
1529  * look for inline back ref. if back ref is found, *ref_ret is set
1530  * to the address of inline back ref, and 0 is returned.
1531  *
1532  * if back ref isn't found, *ref_ret is set to the address where it
1533  * should be inserted, and -ENOENT is returned.
1534  *
1535  * if insert is true and there are too many inline back refs, the path
1536  * points to the extent item, and -EAGAIN is returned.
1537  *
1538  * NOTE: inline back refs are ordered in the same way that back ref
1539  *       items in the tree are ordered.
1540  */
1541 static noinline_for_stack
1542 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1543                                  struct btrfs_fs_info *fs_info,
1544                                  struct btrfs_path *path,
1545                                  struct btrfs_extent_inline_ref **ref_ret,
1546                                  u64 bytenr, u64 num_bytes,
1547                                  u64 parent, u64 root_objectid,
1548                                  u64 owner, u64 offset, int insert)
1549 {
1550         struct btrfs_root *root = fs_info->extent_root;
1551         struct btrfs_key key;
1552         struct extent_buffer *leaf;
1553         struct btrfs_extent_item *ei;
1554         struct btrfs_extent_inline_ref *iref;
1555         u64 flags;
1556         u64 item_size;
1557         unsigned long ptr;
1558         unsigned long end;
1559         int extra_size;
1560         int type;
1561         int want;
1562         int ret;
1563         int err = 0;
1564         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
1565
1566         key.objectid = bytenr;
1567         key.type = BTRFS_EXTENT_ITEM_KEY;
1568         key.offset = num_bytes;
1569
1570         want = extent_ref_type(parent, owner);
1571         if (insert) {
1572                 extra_size = btrfs_extent_inline_ref_size(want);
1573                 path->keep_locks = 1;
1574         } else
1575                 extra_size = -1;
1576
1577         /*
1578          * Owner is our parent level, so we can just add one to get the level
1579          * for the block we are interested in.
1580          */
1581         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1582                 key.type = BTRFS_METADATA_ITEM_KEY;
1583                 key.offset = owner;
1584         }
1585
1586 again:
1587         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1588         if (ret < 0) {
1589                 err = ret;
1590                 goto out;
1591         }
1592
1593         /*
1594          * We may be a newly converted file system which still has the old fat
1595          * extent entries for metadata, so try and see if we have one of those.
1596          */
1597         if (ret > 0 && skinny_metadata) {
1598                 skinny_metadata = false;
1599                 if (path->slots[0]) {
1600                         path->slots[0]--;
1601                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1602                                               path->slots[0]);
1603                         if (key.objectid == bytenr &&
1604                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1605                             key.offset == num_bytes)
1606                                 ret = 0;
1607                 }
1608                 if (ret) {
1609                         key.objectid = bytenr;
1610                         key.type = BTRFS_EXTENT_ITEM_KEY;
1611                         key.offset = num_bytes;
1612                         btrfs_release_path(path);
1613                         goto again;
1614                 }
1615         }
1616
1617         if (ret && !insert) {
1618                 err = -ENOENT;
1619                 goto out;
1620         } else if (WARN_ON(ret)) {
1621                 err = -EIO;
1622                 goto out;
1623         }
1624
1625         leaf = path->nodes[0];
1626         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1627 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1628         if (item_size < sizeof(*ei)) {
1629                 if (!insert) {
1630                         err = -ENOENT;
1631                         goto out;
1632                 }
1633                 ret = convert_extent_item_v0(trans, fs_info, path, owner,
1634                                              extra_size);
1635                 if (ret < 0) {
1636                         err = ret;
1637                         goto out;
1638                 }
1639                 leaf = path->nodes[0];
1640                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1641         }
1642 #endif
1643         BUG_ON(item_size < sizeof(*ei));
1644
1645         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1646         flags = btrfs_extent_flags(leaf, ei);
1647
1648         ptr = (unsigned long)(ei + 1);
1649         end = (unsigned long)ei + item_size;
1650
1651         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1652                 ptr += sizeof(struct btrfs_tree_block_info);
1653                 BUG_ON(ptr > end);
1654         }
1655
1656         err = -ENOENT;
1657         while (1) {
1658                 if (ptr >= end) {
1659                         WARN_ON(ptr > end);
1660                         break;
1661                 }
1662                 iref = (struct btrfs_extent_inline_ref *)ptr;
1663                 type = btrfs_extent_inline_ref_type(leaf, iref);
1664                 if (want < type)
1665                         break;
1666                 if (want > type) {
1667                         ptr += btrfs_extent_inline_ref_size(type);
1668                         continue;
1669                 }
1670
1671                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1672                         struct btrfs_extent_data_ref *dref;
1673                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1674                         if (match_extent_data_ref(leaf, dref, root_objectid,
1675                                                   owner, offset)) {
1676                                 err = 0;
1677                                 break;
1678                         }
1679                         if (hash_extent_data_ref_item(leaf, dref) <
1680                             hash_extent_data_ref(root_objectid, owner, offset))
1681                                 break;
1682                 } else {
1683                         u64 ref_offset;
1684                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1685                         if (parent > 0) {
1686                                 if (parent == ref_offset) {
1687                                         err = 0;
1688                                         break;
1689                                 }
1690                                 if (ref_offset < parent)
1691                                         break;
1692                         } else {
1693                                 if (root_objectid == ref_offset) {
1694                                         err = 0;
1695                                         break;
1696                                 }
1697                                 if (ref_offset < root_objectid)
1698                                         break;
1699                         }
1700                 }
1701                 ptr += btrfs_extent_inline_ref_size(type);
1702         }
1703         if (err == -ENOENT && insert) {
1704                 if (item_size + extra_size >=
1705                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1706                         err = -EAGAIN;
1707                         goto out;
1708                 }
1709                 /*
1710                  * To add new inline back ref, we have to make sure
1711                  * there is no corresponding back ref item.
1712                  * For simplicity, we just do not add new inline back
1713                  * ref if there is any kind of item for this block
1714                  */
1715                 if (find_next_key(path, 0, &key) == 0 &&
1716                     key.objectid == bytenr &&
1717                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1718                         err = -EAGAIN;
1719                         goto out;
1720                 }
1721         }
1722         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1723 out:
1724         if (insert) {
1725                 path->keep_locks = 0;
1726                 btrfs_unlock_up_safe(path, 1);
1727         }
1728         return err;
1729 }
1730
1731 /*
1732  * helper to add new inline back ref
1733  */
1734 static noinline_for_stack
1735 void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
1736                                  struct btrfs_path *path,
1737                                  struct btrfs_extent_inline_ref *iref,
1738                                  u64 parent, u64 root_objectid,
1739                                  u64 owner, u64 offset, int refs_to_add,
1740                                  struct btrfs_delayed_extent_op *extent_op)
1741 {
1742         struct extent_buffer *leaf;
1743         struct btrfs_extent_item *ei;
1744         unsigned long ptr;
1745         unsigned long end;
1746         unsigned long item_offset;
1747         u64 refs;
1748         int size;
1749         int type;
1750
1751         leaf = path->nodes[0];
1752         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1753         item_offset = (unsigned long)iref - (unsigned long)ei;
1754
1755         type = extent_ref_type(parent, owner);
1756         size = btrfs_extent_inline_ref_size(type);
1757
1758         btrfs_extend_item(fs_info, path, size);
1759
1760         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1761         refs = btrfs_extent_refs(leaf, ei);
1762         refs += refs_to_add;
1763         btrfs_set_extent_refs(leaf, ei, refs);
1764         if (extent_op)
1765                 __run_delayed_extent_op(extent_op, leaf, ei);
1766
1767         ptr = (unsigned long)ei + item_offset;
1768         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1769         if (ptr < end - size)
1770                 memmove_extent_buffer(leaf, ptr + size, ptr,
1771                                       end - size - ptr);
1772
1773         iref = (struct btrfs_extent_inline_ref *)ptr;
1774         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1775         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1776                 struct btrfs_extent_data_ref *dref;
1777                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1778                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1779                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1780                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1781                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1782         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1783                 struct btrfs_shared_data_ref *sref;
1784                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1785                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1786                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1787         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1788                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1789         } else {
1790                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1791         }
1792         btrfs_mark_buffer_dirty(leaf);
1793 }
1794
1795 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1796                                  struct btrfs_fs_info *fs_info,
1797                                  struct btrfs_path *path,
1798                                  struct btrfs_extent_inline_ref **ref_ret,
1799                                  u64 bytenr, u64 num_bytes, u64 parent,
1800                                  u64 root_objectid, u64 owner, u64 offset)
1801 {
1802         int ret;
1803
1804         ret = lookup_inline_extent_backref(trans, fs_info, path, ref_ret,
1805                                            bytenr, num_bytes, parent,
1806                                            root_objectid, owner, offset, 0);
1807         if (ret != -ENOENT)
1808                 return ret;
1809
1810         btrfs_release_path(path);
1811         *ref_ret = NULL;
1812
1813         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1814                 ret = lookup_tree_block_ref(trans, fs_info, path, bytenr,
1815                                             parent, root_objectid);
1816         } else {
1817                 ret = lookup_extent_data_ref(trans, fs_info, path, bytenr,
1818                                              parent, root_objectid, owner,
1819                                              offset);
1820         }
1821         return ret;
1822 }
1823
1824 /*
1825  * helper to update/remove inline back ref
1826  */
1827 static noinline_for_stack
1828 void update_inline_extent_backref(struct btrfs_fs_info *fs_info,
1829                                   struct btrfs_path *path,
1830                                   struct btrfs_extent_inline_ref *iref,
1831                                   int refs_to_mod,
1832                                   struct btrfs_delayed_extent_op *extent_op,
1833                                   int *last_ref)
1834 {
1835         struct extent_buffer *leaf;
1836         struct btrfs_extent_item *ei;
1837         struct btrfs_extent_data_ref *dref = NULL;
1838         struct btrfs_shared_data_ref *sref = NULL;
1839         unsigned long ptr;
1840         unsigned long end;
1841         u32 item_size;
1842         int size;
1843         int type;
1844         u64 refs;
1845
1846         leaf = path->nodes[0];
1847         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1848         refs = btrfs_extent_refs(leaf, ei);
1849         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1850         refs += refs_to_mod;
1851         btrfs_set_extent_refs(leaf, ei, refs);
1852         if (extent_op)
1853                 __run_delayed_extent_op(extent_op, leaf, ei);
1854
1855         type = btrfs_extent_inline_ref_type(leaf, iref);
1856
1857         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1858                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1859                 refs = btrfs_extent_data_ref_count(leaf, dref);
1860         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1861                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1862                 refs = btrfs_shared_data_ref_count(leaf, sref);
1863         } else {
1864                 refs = 1;
1865                 BUG_ON(refs_to_mod != -1);
1866         }
1867
1868         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1869         refs += refs_to_mod;
1870
1871         if (refs > 0) {
1872                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1873                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1874                 else
1875                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1876         } else {
1877                 *last_ref = 1;
1878                 size =  btrfs_extent_inline_ref_size(type);
1879                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1880                 ptr = (unsigned long)iref;
1881                 end = (unsigned long)ei + item_size;
1882                 if (ptr + size < end)
1883                         memmove_extent_buffer(leaf, ptr, ptr + size,
1884                                               end - ptr - size);
1885                 item_size -= size;
1886                 btrfs_truncate_item(fs_info, path, item_size, 1);
1887         }
1888         btrfs_mark_buffer_dirty(leaf);
1889 }
1890
1891 static noinline_for_stack
1892 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1893                                  struct btrfs_fs_info *fs_info,
1894                                  struct btrfs_path *path,
1895                                  u64 bytenr, u64 num_bytes, u64 parent,
1896                                  u64 root_objectid, u64 owner,
1897                                  u64 offset, int refs_to_add,
1898                                  struct btrfs_delayed_extent_op *extent_op)
1899 {
1900         struct btrfs_extent_inline_ref *iref;
1901         int ret;
1902
1903         ret = lookup_inline_extent_backref(trans, fs_info, path, &iref,
1904                                            bytenr, num_bytes, parent,
1905                                            root_objectid, owner, offset, 1);
1906         if (ret == 0) {
1907                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1908                 update_inline_extent_backref(fs_info, path, iref,
1909                                              refs_to_add, extent_op, NULL);
1910         } else if (ret == -ENOENT) {
1911                 setup_inline_extent_backref(fs_info, path, iref, parent,
1912                                             root_objectid, owner, offset,
1913                                             refs_to_add, extent_op);
1914                 ret = 0;
1915         }
1916         return ret;
1917 }
1918
1919 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1920                                  struct btrfs_fs_info *fs_info,
1921                                  struct btrfs_path *path,
1922                                  u64 bytenr, u64 parent, u64 root_objectid,
1923                                  u64 owner, u64 offset, int refs_to_add)
1924 {
1925         int ret;
1926         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1927                 BUG_ON(refs_to_add != 1);
1928                 ret = insert_tree_block_ref(trans, fs_info, path, bytenr,
1929                                             parent, root_objectid);
1930         } else {
1931                 ret = insert_extent_data_ref(trans, fs_info, path, bytenr,
1932                                              parent, root_objectid,
1933                                              owner, offset, refs_to_add);
1934         }
1935         return ret;
1936 }
1937
1938 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1939                                  struct btrfs_fs_info *fs_info,
1940                                  struct btrfs_path *path,
1941                                  struct btrfs_extent_inline_ref *iref,
1942                                  int refs_to_drop, int is_data, int *last_ref)
1943 {
1944         int ret = 0;
1945
1946         BUG_ON(!is_data && refs_to_drop != 1);
1947         if (iref) {
1948                 update_inline_extent_backref(fs_info, path, iref,
1949                                              -refs_to_drop, NULL, last_ref);
1950         } else if (is_data) {
1951                 ret = remove_extent_data_ref(trans, fs_info, path, refs_to_drop,
1952                                              last_ref);
1953         } else {
1954                 *last_ref = 1;
1955                 ret = btrfs_del_item(trans, fs_info->extent_root, path);
1956         }
1957         return ret;
1958 }
1959
1960 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
1961 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1962                                u64 *discarded_bytes)
1963 {
1964         int j, ret = 0;
1965         u64 bytes_left, end;
1966         u64 aligned_start = ALIGN(start, 1 << 9);
1967
1968         if (WARN_ON(start != aligned_start)) {
1969                 len -= aligned_start - start;
1970                 len = round_down(len, 1 << 9);
1971                 start = aligned_start;
1972         }
1973
1974         *discarded_bytes = 0;
1975
1976         if (!len)
1977                 return 0;
1978
1979         end = start + len;
1980         bytes_left = len;
1981
1982         /* Skip any superblocks on this device. */
1983         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1984                 u64 sb_start = btrfs_sb_offset(j);
1985                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1986                 u64 size = sb_start - start;
1987
1988                 if (!in_range(sb_start, start, bytes_left) &&
1989                     !in_range(sb_end, start, bytes_left) &&
1990                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1991                         continue;
1992
1993                 /*
1994                  * Superblock spans beginning of range.  Adjust start and
1995                  * try again.
1996                  */
1997                 if (sb_start <= start) {
1998                         start += sb_end - start;
1999                         if (start > end) {
2000                                 bytes_left = 0;
2001                                 break;
2002                         }
2003                         bytes_left = end - start;
2004                         continue;
2005                 }
2006
2007                 if (size) {
2008                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2009                                                    GFP_NOFS, 0);
2010                         if (!ret)
2011                                 *discarded_bytes += size;
2012                         else if (ret != -EOPNOTSUPP)
2013                                 return ret;
2014                 }
2015
2016                 start = sb_end;
2017                 if (start > end) {
2018                         bytes_left = 0;
2019                         break;
2020                 }
2021                 bytes_left = end - start;
2022         }
2023
2024         if (bytes_left) {
2025                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2026                                            GFP_NOFS, 0);
2027                 if (!ret)
2028                         *discarded_bytes += bytes_left;
2029         }
2030         return ret;
2031 }
2032
2033 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
2034                          u64 num_bytes, u64 *actual_bytes)
2035 {
2036         int ret;
2037         u64 discarded_bytes = 0;
2038         struct btrfs_bio *bbio = NULL;
2039
2040
2041         /*
2042          * Avoid races with device replace and make sure our bbio has devices
2043          * associated to its stripes that don't go away while we are discarding.
2044          */
2045         btrfs_bio_counter_inc_blocked(fs_info);
2046         /* Tell the block device(s) that the sectors can be discarded */
2047         ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
2048                               &bbio, 0);
2049         /* Error condition is -ENOMEM */
2050         if (!ret) {
2051                 struct btrfs_bio_stripe *stripe = bbio->stripes;
2052                 int i;
2053
2054
2055                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2056                         u64 bytes;
2057                         if (!stripe->dev->can_discard)
2058                                 continue;
2059
2060                         ret = btrfs_issue_discard(stripe->dev->bdev,
2061                                                   stripe->physical,
2062                                                   stripe->length,
2063                                                   &bytes);
2064                         if (!ret)
2065                                 discarded_bytes += bytes;
2066                         else if (ret != -EOPNOTSUPP)
2067                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2068
2069                         /*
2070                          * Just in case we get back EOPNOTSUPP for some reason,
2071                          * just ignore the return value so we don't screw up
2072                          * people calling discard_extent.
2073                          */
2074                         ret = 0;
2075                 }
2076                 btrfs_put_bbio(bbio);
2077         }
2078         btrfs_bio_counter_dec(fs_info);
2079
2080         if (actual_bytes)
2081                 *actual_bytes = discarded_bytes;
2082
2083
2084         if (ret == -EOPNOTSUPP)
2085                 ret = 0;
2086         return ret;
2087 }
2088
2089 /* Can return -ENOMEM */
2090 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2091                          struct btrfs_fs_info *fs_info,
2092                          u64 bytenr, u64 num_bytes, u64 parent,
2093                          u64 root_objectid, u64 owner, u64 offset)
2094 {
2095         int ret;
2096
2097         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2098                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2099
2100         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2101                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2102                                         num_bytes,
2103                                         parent, root_objectid, (int)owner,
2104                                         BTRFS_ADD_DELAYED_REF, NULL);
2105         } else {
2106                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2107                                         num_bytes, parent, root_objectid,
2108                                         owner, offset, 0,
2109                                         BTRFS_ADD_DELAYED_REF);
2110         }
2111         return ret;
2112 }
2113
2114 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2115                                   struct btrfs_fs_info *fs_info,
2116                                   struct btrfs_delayed_ref_node *node,
2117                                   u64 parent, u64 root_objectid,
2118                                   u64 owner, u64 offset, int refs_to_add,
2119                                   struct btrfs_delayed_extent_op *extent_op)
2120 {
2121         struct btrfs_path *path;
2122         struct extent_buffer *leaf;
2123         struct btrfs_extent_item *item;
2124         struct btrfs_key key;
2125         u64 bytenr = node->bytenr;
2126         u64 num_bytes = node->num_bytes;
2127         u64 refs;
2128         int ret;
2129
2130         path = btrfs_alloc_path();
2131         if (!path)
2132                 return -ENOMEM;
2133
2134         path->reada = READA_FORWARD;
2135         path->leave_spinning = 1;
2136         /* this will setup the path even if it fails to insert the back ref */
2137         ret = insert_inline_extent_backref(trans, fs_info, path, bytenr,
2138                                            num_bytes, parent, root_objectid,
2139                                            owner, offset,
2140                                            refs_to_add, extent_op);
2141         if ((ret < 0 && ret != -EAGAIN) || !ret)
2142                 goto out;
2143
2144         /*
2145          * Ok we had -EAGAIN which means we didn't have space to insert and
2146          * inline extent ref, so just update the reference count and add a
2147          * normal backref.
2148          */
2149         leaf = path->nodes[0];
2150         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2151         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2152         refs = btrfs_extent_refs(leaf, item);
2153         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2154         if (extent_op)
2155                 __run_delayed_extent_op(extent_op, leaf, item);
2156
2157         btrfs_mark_buffer_dirty(leaf);
2158         btrfs_release_path(path);
2159
2160         path->reada = READA_FORWARD;
2161         path->leave_spinning = 1;
2162         /* now insert the actual backref */
2163         ret = insert_extent_backref(trans, fs_info, path, bytenr, parent,
2164                                     root_objectid, owner, offset, refs_to_add);
2165         if (ret)
2166                 btrfs_abort_transaction(trans, ret);
2167 out:
2168         btrfs_free_path(path);
2169         return ret;
2170 }
2171
2172 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2173                                 struct btrfs_fs_info *fs_info,
2174                                 struct btrfs_delayed_ref_node *node,
2175                                 struct btrfs_delayed_extent_op *extent_op,
2176                                 int insert_reserved)
2177 {
2178         int ret = 0;
2179         struct btrfs_delayed_data_ref *ref;
2180         struct btrfs_key ins;
2181         u64 parent = 0;
2182         u64 ref_root = 0;
2183         u64 flags = 0;
2184
2185         ins.objectid = node->bytenr;
2186         ins.offset = node->num_bytes;
2187         ins.type = BTRFS_EXTENT_ITEM_KEY;
2188
2189         ref = btrfs_delayed_node_to_data_ref(node);
2190         trace_run_delayed_data_ref(fs_info, node, ref, node->action);
2191
2192         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2193                 parent = ref->parent;
2194         ref_root = ref->root;
2195
2196         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2197                 if (extent_op)
2198                         flags |= extent_op->flags_to_set;
2199                 ret = alloc_reserved_file_extent(trans, fs_info,
2200                                                  parent, ref_root, flags,
2201                                                  ref->objectid, ref->offset,
2202                                                  &ins, node->ref_mod);
2203         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2204                 ret = __btrfs_inc_extent_ref(trans, fs_info, node, parent,
2205                                              ref_root, ref->objectid,
2206                                              ref->offset, node->ref_mod,
2207                                              extent_op);
2208         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2209                 ret = __btrfs_free_extent(trans, fs_info, node, parent,
2210                                           ref_root, ref->objectid,
2211                                           ref->offset, node->ref_mod,
2212                                           extent_op);
2213         } else {
2214                 BUG();
2215         }
2216         return ret;
2217 }
2218
2219 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2220                                     struct extent_buffer *leaf,
2221                                     struct btrfs_extent_item *ei)
2222 {
2223         u64 flags = btrfs_extent_flags(leaf, ei);
2224         if (extent_op->update_flags) {
2225                 flags |= extent_op->flags_to_set;
2226                 btrfs_set_extent_flags(leaf, ei, flags);
2227         }
2228
2229         if (extent_op->update_key) {
2230                 struct btrfs_tree_block_info *bi;
2231                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2232                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2233                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2234         }
2235 }
2236
2237 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2238                                  struct btrfs_fs_info *fs_info,
2239                                  struct btrfs_delayed_ref_node *node,
2240                                  struct btrfs_delayed_extent_op *extent_op)
2241 {
2242         struct btrfs_key key;
2243         struct btrfs_path *path;
2244         struct btrfs_extent_item *ei;
2245         struct extent_buffer *leaf;
2246         u32 item_size;
2247         int ret;
2248         int err = 0;
2249         int metadata = !extent_op->is_data;
2250
2251         if (trans->aborted)
2252                 return 0;
2253
2254         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2255                 metadata = 0;
2256
2257         path = btrfs_alloc_path();
2258         if (!path)
2259                 return -ENOMEM;
2260
2261         key.objectid = node->bytenr;
2262
2263         if (metadata) {
2264                 key.type = BTRFS_METADATA_ITEM_KEY;
2265                 key.offset = extent_op->level;
2266         } else {
2267                 key.type = BTRFS_EXTENT_ITEM_KEY;
2268                 key.offset = node->num_bytes;
2269         }
2270
2271 again:
2272         path->reada = READA_FORWARD;
2273         path->leave_spinning = 1;
2274         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
2275         if (ret < 0) {
2276                 err = ret;
2277                 goto out;
2278         }
2279         if (ret > 0) {
2280                 if (metadata) {
2281                         if (path->slots[0] > 0) {
2282                                 path->slots[0]--;
2283                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2284                                                       path->slots[0]);
2285                                 if (key.objectid == node->bytenr &&
2286                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2287                                     key.offset == node->num_bytes)
2288                                         ret = 0;
2289                         }
2290                         if (ret > 0) {
2291                                 btrfs_release_path(path);
2292                                 metadata = 0;
2293
2294                                 key.objectid = node->bytenr;
2295                                 key.offset = node->num_bytes;
2296                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2297                                 goto again;
2298                         }
2299                 } else {
2300                         err = -EIO;
2301                         goto out;
2302                 }
2303         }
2304
2305         leaf = path->nodes[0];
2306         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2307 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2308         if (item_size < sizeof(*ei)) {
2309                 ret = convert_extent_item_v0(trans, fs_info, path, (u64)-1, 0);
2310                 if (ret < 0) {
2311                         err = ret;
2312                         goto out;
2313                 }
2314                 leaf = path->nodes[0];
2315                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2316         }
2317 #endif
2318         BUG_ON(item_size < sizeof(*ei));
2319         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2320         __run_delayed_extent_op(extent_op, leaf, ei);
2321
2322         btrfs_mark_buffer_dirty(leaf);
2323 out:
2324         btrfs_free_path(path);
2325         return err;
2326 }
2327
2328 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2329                                 struct btrfs_fs_info *fs_info,
2330                                 struct btrfs_delayed_ref_node *node,
2331                                 struct btrfs_delayed_extent_op *extent_op,
2332                                 int insert_reserved)
2333 {
2334         int ret = 0;
2335         struct btrfs_delayed_tree_ref *ref;
2336         struct btrfs_key ins;
2337         u64 parent = 0;
2338         u64 ref_root = 0;
2339         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
2340
2341         ref = btrfs_delayed_node_to_tree_ref(node);
2342         trace_run_delayed_tree_ref(fs_info, node, ref, node->action);
2343
2344         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2345                 parent = ref->parent;
2346         ref_root = ref->root;
2347
2348         ins.objectid = node->bytenr;
2349         if (skinny_metadata) {
2350                 ins.offset = ref->level;
2351                 ins.type = BTRFS_METADATA_ITEM_KEY;
2352         } else {
2353                 ins.offset = node->num_bytes;
2354                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2355         }
2356
2357         if (node->ref_mod != 1) {
2358                 btrfs_err(fs_info,
2359         "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
2360                           node->bytenr, node->ref_mod, node->action, ref_root,
2361                           parent);
2362                 return -EIO;
2363         }
2364         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2365                 BUG_ON(!extent_op || !extent_op->update_flags);
2366                 ret = alloc_reserved_tree_block(trans, fs_info,
2367                                                 parent, ref_root,
2368                                                 extent_op->flags_to_set,
2369                                                 &extent_op->key,
2370                                                 ref->level, &ins);
2371         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2372                 ret = __btrfs_inc_extent_ref(trans, fs_info, node,
2373                                              parent, ref_root,
2374                                              ref->level, 0, 1,
2375                                              extent_op);
2376         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2377                 ret = __btrfs_free_extent(trans, fs_info, node,
2378                                           parent, ref_root,
2379                                           ref->level, 0, 1, extent_op);
2380         } else {
2381                 BUG();
2382         }
2383         return ret;
2384 }
2385
2386 /* helper function to actually process a single delayed ref entry */
2387 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2388                                struct btrfs_fs_info *fs_info,
2389                                struct btrfs_delayed_ref_node *node,
2390                                struct btrfs_delayed_extent_op *extent_op,
2391                                int insert_reserved)
2392 {
2393         int ret = 0;
2394
2395         if (trans->aborted) {
2396                 if (insert_reserved)
2397                         btrfs_pin_extent(fs_info, node->bytenr,
2398                                          node->num_bytes, 1);
2399                 return 0;
2400         }
2401
2402         if (btrfs_delayed_ref_is_head(node)) {
2403                 struct btrfs_delayed_ref_head *head;
2404                 /*
2405                  * we've hit the end of the chain and we were supposed
2406                  * to insert this extent into the tree.  But, it got
2407                  * deleted before we ever needed to insert it, so all
2408                  * we have to do is clean up the accounting
2409                  */
2410                 BUG_ON(extent_op);
2411                 head = btrfs_delayed_node_to_head(node);
2412                 trace_run_delayed_ref_head(fs_info, node, head, node->action);
2413
2414                 if (insert_reserved) {
2415                         btrfs_pin_extent(fs_info, node->bytenr,
2416                                          node->num_bytes, 1);
2417                         if (head->is_data) {
2418                                 ret = btrfs_del_csums(trans, fs_info,
2419                                                       node->bytenr,
2420                                                       node->num_bytes);
2421                         }
2422                 }
2423
2424                 /* Also free its reserved qgroup space */
2425                 btrfs_qgroup_free_delayed_ref(fs_info, head->qgroup_ref_root,
2426                                               head->qgroup_reserved);
2427                 return ret;
2428         }
2429
2430         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2431             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2432                 ret = run_delayed_tree_ref(trans, fs_info, node, extent_op,
2433                                            insert_reserved);
2434         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2435                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2436                 ret = run_delayed_data_ref(trans, fs_info, node, extent_op,
2437                                            insert_reserved);
2438         else
2439                 BUG();
2440         return ret;
2441 }
2442
2443 static inline struct btrfs_delayed_ref_node *
2444 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2445 {
2446         struct btrfs_delayed_ref_node *ref;
2447
2448         if (list_empty(&head->ref_list))
2449                 return NULL;
2450
2451         /*
2452          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2453          * This is to prevent a ref count from going down to zero, which deletes
2454          * the extent item from the extent tree, when there still are references
2455          * to add, which would fail because they would not find the extent item.
2456          */
2457         if (!list_empty(&head->ref_add_list))
2458                 return list_first_entry(&head->ref_add_list,
2459                                 struct btrfs_delayed_ref_node, add_list);
2460
2461         ref = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
2462                                list);
2463         ASSERT(list_empty(&ref->add_list));
2464         return ref;
2465 }
2466
2467 /*
2468  * Returns 0 on success or if called with an already aborted transaction.
2469  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2470  */
2471 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2472                                              struct btrfs_fs_info *fs_info,
2473                                              unsigned long nr)
2474 {
2475         struct btrfs_delayed_ref_root *delayed_refs;
2476         struct btrfs_delayed_ref_node *ref;
2477         struct btrfs_delayed_ref_head *locked_ref = NULL;
2478         struct btrfs_delayed_extent_op *extent_op;
2479         ktime_t start = ktime_get();
2480         int ret;
2481         unsigned long count = 0;
2482         unsigned long actual_count = 0;
2483         int must_insert_reserved = 0;
2484
2485         delayed_refs = &trans->transaction->delayed_refs;
2486         while (1) {
2487                 if (!locked_ref) {
2488                         if (count >= nr)
2489                                 break;
2490
2491                         spin_lock(&delayed_refs->lock);
2492                         locked_ref = btrfs_select_ref_head(trans);
2493                         if (!locked_ref) {
2494                                 spin_unlock(&delayed_refs->lock);
2495                                 break;
2496                         }
2497
2498                         /* grab the lock that says we are going to process
2499                          * all the refs for this head */
2500                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2501                         spin_unlock(&delayed_refs->lock);
2502                         /*
2503                          * we may have dropped the spin lock to get the head
2504                          * mutex lock, and that might have given someone else
2505                          * time to free the head.  If that's true, it has been
2506                          * removed from our list and we can move on.
2507                          */
2508                         if (ret == -EAGAIN) {
2509                                 locked_ref = NULL;
2510                                 count++;
2511                                 continue;
2512                         }
2513                 }
2514
2515                 /*
2516                  * We need to try and merge add/drops of the same ref since we
2517                  * can run into issues with relocate dropping the implicit ref
2518                  * and then it being added back again before the drop can
2519                  * finish.  If we merged anything we need to re-loop so we can
2520                  * get a good ref.
2521                  * Or we can get node references of the same type that weren't
2522                  * merged when created due to bumps in the tree mod seq, and
2523                  * we need to merge them to prevent adding an inline extent
2524                  * backref before dropping it (triggering a BUG_ON at
2525                  * insert_inline_extent_backref()).
2526                  */
2527                 spin_lock(&locked_ref->lock);
2528                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2529                                          locked_ref);
2530
2531                 /*
2532                  * locked_ref is the head node, so we have to go one
2533                  * node back for any delayed ref updates
2534                  */
2535                 ref = select_delayed_ref(locked_ref);
2536
2537                 if (ref && ref->seq &&
2538                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2539                         spin_unlock(&locked_ref->lock);
2540                         spin_lock(&delayed_refs->lock);
2541                         locked_ref->processing = 0;
2542                         delayed_refs->num_heads_ready++;
2543                         spin_unlock(&delayed_refs->lock);
2544                         btrfs_delayed_ref_unlock(locked_ref);
2545                         locked_ref = NULL;
2546                         cond_resched();
2547                         count++;
2548                         continue;
2549                 }
2550
2551                 /*
2552                  * record the must insert reserved flag before we
2553                  * drop the spin lock.
2554                  */
2555                 must_insert_reserved = locked_ref->must_insert_reserved;
2556                 locked_ref->must_insert_reserved = 0;
2557
2558                 extent_op = locked_ref->extent_op;
2559                 locked_ref->extent_op = NULL;
2560
2561                 if (!ref) {
2562
2563
2564                         /* All delayed refs have been processed, Go ahead
2565                          * and send the head node to run_one_delayed_ref,
2566                          * so that any accounting fixes can happen
2567                          */
2568                         ref = &locked_ref->node;
2569
2570                         if (extent_op && must_insert_reserved) {
2571                                 btrfs_free_delayed_extent_op(extent_op);
2572                                 extent_op = NULL;
2573                         }
2574
2575                         if (extent_op) {
2576                                 spin_unlock(&locked_ref->lock);
2577                                 ret = run_delayed_extent_op(trans, fs_info,
2578                                                             ref, extent_op);
2579                                 btrfs_free_delayed_extent_op(extent_op);
2580
2581                                 if (ret) {
2582                                         /*
2583                                          * Need to reset must_insert_reserved if
2584                                          * there was an error so the abort stuff
2585                                          * can cleanup the reserved space
2586                                          * properly.
2587                                          */
2588                                         if (must_insert_reserved)
2589                                                 locked_ref->must_insert_reserved = 1;
2590                                         spin_lock(&delayed_refs->lock);
2591                                         locked_ref->processing = 0;
2592                                         delayed_refs->num_heads_ready++;
2593                                         spin_unlock(&delayed_refs->lock);
2594                                         btrfs_debug(fs_info,
2595                                                     "run_delayed_extent_op returned %d",
2596                                                     ret);
2597                                         btrfs_delayed_ref_unlock(locked_ref);
2598                                         return ret;
2599                                 }
2600                                 continue;
2601                         }
2602
2603                         /*
2604                          * Need to drop our head ref lock and re-acquire the
2605                          * delayed ref lock and then re-check to make sure
2606                          * nobody got added.
2607                          */
2608                         spin_unlock(&locked_ref->lock);
2609                         spin_lock(&delayed_refs->lock);
2610                         spin_lock(&locked_ref->lock);
2611                         if (!list_empty(&locked_ref->ref_list) ||
2612                             locked_ref->extent_op) {
2613                                 spin_unlock(&locked_ref->lock);
2614                                 spin_unlock(&delayed_refs->lock);
2615                                 continue;
2616                         }
2617                         ref->in_tree = 0;
2618                         delayed_refs->num_heads--;
2619                         rb_erase(&locked_ref->href_node,
2620                                  &delayed_refs->href_root);
2621                         spin_unlock(&delayed_refs->lock);
2622                 } else {
2623                         actual_count++;
2624                         ref->in_tree = 0;
2625                         list_del(&ref->list);
2626                         if (!list_empty(&ref->add_list))
2627                                 list_del(&ref->add_list);
2628                 }
2629                 atomic_dec(&delayed_refs->num_entries);
2630
2631                 if (!btrfs_delayed_ref_is_head(ref)) {
2632                         /*
2633                          * when we play the delayed ref, also correct the
2634                          * ref_mod on head
2635                          */
2636                         switch (ref->action) {
2637                         case BTRFS_ADD_DELAYED_REF:
2638                         case BTRFS_ADD_DELAYED_EXTENT:
2639                                 locked_ref->node.ref_mod -= ref->ref_mod;
2640                                 break;
2641                         case BTRFS_DROP_DELAYED_REF:
2642                                 locked_ref->node.ref_mod += ref->ref_mod;
2643                                 break;
2644                         default:
2645                                 WARN_ON(1);
2646                         }
2647                 }
2648                 spin_unlock(&locked_ref->lock);
2649
2650                 ret = run_one_delayed_ref(trans, fs_info, ref, extent_op,
2651                                           must_insert_reserved);
2652
2653                 btrfs_free_delayed_extent_op(extent_op);
2654                 if (ret) {
2655                         spin_lock(&delayed_refs->lock);
2656                         locked_ref->processing = 0;
2657                         delayed_refs->num_heads_ready++;
2658                         spin_unlock(&delayed_refs->lock);
2659                         btrfs_delayed_ref_unlock(locked_ref);
2660                         btrfs_put_delayed_ref(ref);
2661                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
2662                                     ret);
2663                         return ret;
2664                 }
2665
2666                 /*
2667                  * If this node is a head, that means all the refs in this head
2668                  * have been dealt with, and we will pick the next head to deal
2669                  * with, so we must unlock the head and drop it from the cluster
2670                  * list before we release it.
2671                  */
2672                 if (btrfs_delayed_ref_is_head(ref)) {
2673                         if (locked_ref->is_data &&
2674                             locked_ref->total_ref_mod < 0) {
2675                                 spin_lock(&delayed_refs->lock);
2676                                 delayed_refs->pending_csums -= ref->num_bytes;
2677                                 spin_unlock(&delayed_refs->lock);
2678                         }
2679                         btrfs_delayed_ref_unlock(locked_ref);
2680                         locked_ref = NULL;
2681                 }
2682                 btrfs_put_delayed_ref(ref);
2683                 count++;
2684                 cond_resched();
2685         }
2686
2687         /*
2688          * We don't want to include ref heads since we can have empty ref heads
2689          * and those will drastically skew our runtime down since we just do
2690          * accounting, no actual extent tree updates.
2691          */
2692         if (actual_count > 0) {
2693                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2694                 u64 avg;
2695
2696                 /*
2697                  * We weigh the current average higher than our current runtime
2698                  * to avoid large swings in the average.
2699                  */
2700                 spin_lock(&delayed_refs->lock);
2701                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2702                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2703                 spin_unlock(&delayed_refs->lock);
2704         }
2705         return 0;
2706 }
2707
2708 #ifdef SCRAMBLE_DELAYED_REFS
2709 /*
2710  * Normally delayed refs get processed in ascending bytenr order. This
2711  * correlates in most cases to the order added. To expose dependencies on this
2712  * order, we start to process the tree in the middle instead of the beginning
2713  */
2714 static u64 find_middle(struct rb_root *root)
2715 {
2716         struct rb_node *n = root->rb_node;
2717         struct btrfs_delayed_ref_node *entry;
2718         int alt = 1;
2719         u64 middle;
2720         u64 first = 0, last = 0;
2721
2722         n = rb_first(root);
2723         if (n) {
2724                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2725                 first = entry->bytenr;
2726         }
2727         n = rb_last(root);
2728         if (n) {
2729                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2730                 last = entry->bytenr;
2731         }
2732         n = root->rb_node;
2733
2734         while (n) {
2735                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2736                 WARN_ON(!entry->in_tree);
2737
2738                 middle = entry->bytenr;
2739
2740                 if (alt)
2741                         n = n->rb_left;
2742                 else
2743                         n = n->rb_right;
2744
2745                 alt = 1 - alt;
2746         }
2747         return middle;
2748 }
2749 #endif
2750
2751 static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
2752 {
2753         u64 num_bytes;
2754
2755         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2756                              sizeof(struct btrfs_extent_inline_ref));
2757         if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2758                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2759
2760         /*
2761          * We don't ever fill up leaves all the way so multiply by 2 just to be
2762          * closer to what we're really going to want to use.
2763          */
2764         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
2765 }
2766
2767 /*
2768  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2769  * would require to store the csums for that many bytes.
2770  */
2771 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2772 {
2773         u64 csum_size;
2774         u64 num_csums_per_leaf;
2775         u64 num_csums;
2776
2777         csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2778         num_csums_per_leaf = div64_u64(csum_size,
2779                         (u64)btrfs_super_csum_size(fs_info->super_copy));
2780         num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2781         num_csums += num_csums_per_leaf - 1;
2782         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2783         return num_csums;
2784 }
2785
2786 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2787                                        struct btrfs_fs_info *fs_info)
2788 {
2789         struct btrfs_block_rsv *global_rsv;
2790         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2791         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2792         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2793         u64 num_bytes, num_dirty_bgs_bytes;
2794         int ret = 0;
2795
2796         num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
2797         num_heads = heads_to_leaves(fs_info, num_heads);
2798         if (num_heads > 1)
2799                 num_bytes += (num_heads - 1) * fs_info->nodesize;
2800         num_bytes <<= 1;
2801         num_bytes += btrfs_csum_bytes_to_leaves(fs_info, csum_bytes) *
2802                                                         fs_info->nodesize;
2803         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(fs_info,
2804                                                              num_dirty_bgs);
2805         global_rsv = &fs_info->global_block_rsv;
2806
2807         /*
2808          * If we can't allocate any more chunks lets make sure we have _lots_ of
2809          * wiggle room since running delayed refs can create more delayed refs.
2810          */
2811         if (global_rsv->space_info->full) {
2812                 num_dirty_bgs_bytes <<= 1;
2813                 num_bytes <<= 1;
2814         }
2815
2816         spin_lock(&global_rsv->lock);
2817         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2818                 ret = 1;
2819         spin_unlock(&global_rsv->lock);
2820         return ret;
2821 }
2822
2823 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2824                                        struct btrfs_fs_info *fs_info)
2825 {
2826         u64 num_entries =
2827                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2828         u64 avg_runtime;
2829         u64 val;
2830
2831         smp_mb();
2832         avg_runtime = fs_info->avg_delayed_ref_runtime;
2833         val = num_entries * avg_runtime;
2834         if (val >= NSEC_PER_SEC)
2835                 return 1;
2836         if (val >= NSEC_PER_SEC / 2)
2837                 return 2;
2838
2839         return btrfs_check_space_for_delayed_refs(trans, fs_info);
2840 }
2841
2842 struct async_delayed_refs {
2843         struct btrfs_root *root;
2844         u64 transid;
2845         int count;
2846         int error;
2847         int sync;
2848         struct completion wait;
2849         struct btrfs_work work;
2850 };
2851
2852 static inline struct async_delayed_refs *
2853 to_async_delayed_refs(struct btrfs_work *work)
2854 {
2855         return container_of(work, struct async_delayed_refs, work);
2856 }
2857
2858 static void delayed_ref_async_start(struct btrfs_work *work)
2859 {
2860         struct async_delayed_refs *async = to_async_delayed_refs(work);
2861         struct btrfs_trans_handle *trans;
2862         struct btrfs_fs_info *fs_info = async->root->fs_info;
2863         int ret;
2864
2865         /* if the commit is already started, we don't need to wait here */
2866         if (btrfs_transaction_blocked(fs_info))
2867                 goto done;
2868
2869         trans = btrfs_join_transaction(async->root);
2870         if (IS_ERR(trans)) {
2871                 async->error = PTR_ERR(trans);
2872                 goto done;
2873         }
2874
2875         /*
2876          * trans->sync means that when we call end_transaction, we won't
2877          * wait on delayed refs
2878          */
2879         trans->sync = true;
2880
2881         /* Don't bother flushing if we got into a different transaction */
2882         if (trans->transid > async->transid)
2883                 goto end;
2884
2885         ret = btrfs_run_delayed_refs(trans, fs_info, async->count);
2886         if (ret)
2887                 async->error = ret;
2888 end:
2889         ret = btrfs_end_transaction(trans);
2890         if (ret && !async->error)
2891                 async->error = ret;
2892 done:
2893         if (async->sync)
2894                 complete(&async->wait);
2895         else
2896                 kfree(async);
2897 }
2898
2899 int btrfs_async_run_delayed_refs(struct btrfs_fs_info *fs_info,
2900                                  unsigned long count, u64 transid, int wait)
2901 {
2902         struct async_delayed_refs *async;
2903         int ret;
2904
2905         async = kmalloc(sizeof(*async), GFP_NOFS);
2906         if (!async)
2907                 return -ENOMEM;
2908
2909         async->root = fs_info->tree_root;
2910         async->count = count;
2911         async->error = 0;
2912         async->transid = transid;
2913         if (wait)
2914                 async->sync = 1;
2915         else
2916                 async->sync = 0;
2917         init_completion(&async->wait);
2918
2919         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2920                         delayed_ref_async_start, NULL, NULL);
2921
2922         btrfs_queue_work(fs_info->extent_workers, &async->work);
2923
2924         if (wait) {
2925                 wait_for_completion(&async->wait);
2926                 ret = async->error;
2927                 kfree(async);
2928                 return ret;
2929         }
2930         return 0;
2931 }
2932
2933 /*
2934  * this starts processing the delayed reference count updates and
2935  * extent insertions we have queued up so far.  count can be
2936  * 0, which means to process everything in the tree at the start
2937  * of the run (but not newly added entries), or it can be some target
2938  * number you'd like to process.
2939  *
2940  * Returns 0 on success or if called with an aborted transaction
2941  * Returns <0 on error and aborts the transaction
2942  */
2943 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2944                            struct btrfs_fs_info *fs_info, unsigned long count)
2945 {
2946         struct rb_node *node;
2947         struct btrfs_delayed_ref_root *delayed_refs;
2948         struct btrfs_delayed_ref_head *head;
2949         int ret;
2950         int run_all = count == (unsigned long)-1;
2951         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2952
2953         /* We'll clean this up in btrfs_cleanup_transaction */
2954         if (trans->aborted)
2955                 return 0;
2956
2957         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
2958                 return 0;
2959
2960         delayed_refs = &trans->transaction->delayed_refs;
2961         if (count == 0)
2962                 count = atomic_read(&delayed_refs->num_entries) * 2;
2963
2964 again:
2965 #ifdef SCRAMBLE_DELAYED_REFS
2966         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2967 #endif
2968         trans->can_flush_pending_bgs = false;
2969         ret = __btrfs_run_delayed_refs(trans, fs_info, count);
2970         if (ret < 0) {
2971                 btrfs_abort_transaction(trans, ret);
2972                 return ret;
2973         }
2974
2975         if (run_all) {
2976                 if (!list_empty(&trans->new_bgs))
2977                         btrfs_create_pending_block_groups(trans, fs_info);
2978
2979                 spin_lock(&delayed_refs->lock);
2980                 node = rb_first(&delayed_refs->href_root);
2981                 if (!node) {
2982                         spin_unlock(&delayed_refs->lock);
2983                         goto out;
2984                 }
2985
2986                 while (node) {
2987                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2988                                         href_node);
2989                         if (btrfs_delayed_ref_is_head(&head->node)) {
2990                                 struct btrfs_delayed_ref_node *ref;
2991
2992                                 ref = &head->node;
2993                                 refcount_inc(&ref->refs);
2994
2995                                 spin_unlock(&delayed_refs->lock);
2996                                 /*
2997                                  * Mutex was contended, block until it's
2998                                  * released and try again
2999                                  */
3000                                 mutex_lock(&head->mutex);
3001                                 mutex_unlock(&head->mutex);
3002
3003                                 btrfs_put_delayed_ref(ref);
3004                                 cond_resched();
3005                                 goto again;
3006                         } else {
3007                                 WARN_ON(1);
3008                         }
3009                         node = rb_next(node);
3010                 }
3011                 spin_unlock(&delayed_refs->lock);
3012                 cond_resched();
3013                 goto again;
3014         }
3015 out:
3016         trans->can_flush_pending_bgs = can_flush_pending_bgs;
3017         return 0;
3018 }
3019
3020 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3021                                 struct btrfs_fs_info *fs_info,
3022                                 u64 bytenr, u64 num_bytes, u64 flags,
3023                                 int level, int is_data)
3024 {
3025         struct btrfs_delayed_extent_op *extent_op;
3026         int ret;
3027
3028         extent_op = btrfs_alloc_delayed_extent_op();
3029         if (!extent_op)
3030                 return -ENOMEM;
3031
3032         extent_op->flags_to_set = flags;
3033         extent_op->update_flags = true;
3034         extent_op->update_key = false;
3035         extent_op->is_data = is_data ? true : false;
3036         extent_op->level = level;
3037
3038         ret = btrfs_add_delayed_extent_op(fs_info, trans, bytenr,
3039                                           num_bytes, extent_op);
3040         if (ret)
3041                 btrfs_free_delayed_extent_op(extent_op);
3042         return ret;
3043 }
3044
3045 static noinline int check_delayed_ref(struct btrfs_root *root,
3046                                       struct btrfs_path *path,
3047                                       u64 objectid, u64 offset, u64 bytenr)
3048 {
3049         struct btrfs_delayed_ref_head *head;
3050         struct btrfs_delayed_ref_node *ref;
3051         struct btrfs_delayed_data_ref *data_ref;
3052         struct btrfs_delayed_ref_root *delayed_refs;
3053         struct btrfs_transaction *cur_trans;
3054         int ret = 0;
3055
3056         cur_trans = root->fs_info->running_transaction;
3057         if (!cur_trans)
3058                 return 0;
3059
3060         delayed_refs = &cur_trans->delayed_refs;
3061         spin_lock(&delayed_refs->lock);
3062         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3063         if (!head) {
3064                 spin_unlock(&delayed_refs->lock);
3065                 return 0;
3066         }
3067
3068         if (!mutex_trylock(&head->mutex)) {
3069                 refcount_inc(&head->node.refs);
3070                 spin_unlock(&delayed_refs->lock);
3071
3072                 btrfs_release_path(path);
3073
3074                 /*
3075                  * Mutex was contended, block until it's released and let
3076                  * caller try again
3077                  */
3078                 mutex_lock(&head->mutex);
3079                 mutex_unlock(&head->mutex);
3080                 btrfs_put_delayed_ref(&head->node);
3081                 return -EAGAIN;
3082         }
3083         spin_unlock(&delayed_refs->lock);
3084
3085         spin_lock(&head->lock);
3086         list_for_each_entry(ref, &head->ref_list, list) {
3087                 /* If it's a shared ref we know a cross reference exists */
3088                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3089                         ret = 1;
3090                         break;
3091                 }
3092
3093                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3094
3095                 /*
3096                  * If our ref doesn't match the one we're currently looking at
3097                  * then we have a cross reference.
3098                  */
3099                 if (data_ref->root != root->root_key.objectid ||
3100                     data_ref->objectid != objectid ||
3101                     data_ref->offset != offset) {
3102                         ret = 1;
3103                         break;
3104                 }
3105         }
3106         spin_unlock(&head->lock);
3107         mutex_unlock(&head->mutex);
3108         return ret;
3109 }
3110
3111 static noinline int check_committed_ref(struct btrfs_root *root,
3112                                         struct btrfs_path *path,
3113                                         u64 objectid, u64 offset, u64 bytenr)
3114 {
3115         struct btrfs_fs_info *fs_info = root->fs_info;
3116         struct btrfs_root *extent_root = fs_info->extent_root;
3117         struct extent_buffer *leaf;
3118         struct btrfs_extent_data_ref *ref;
3119         struct btrfs_extent_inline_ref *iref;
3120         struct btrfs_extent_item *ei;
3121         struct btrfs_key key;
3122         u32 item_size;
3123         int ret;
3124
3125         key.objectid = bytenr;
3126         key.offset = (u64)-1;
3127         key.type = BTRFS_EXTENT_ITEM_KEY;
3128
3129         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3130         if (ret < 0)
3131                 goto out;
3132         BUG_ON(ret == 0); /* Corruption */
3133
3134         ret = -ENOENT;
3135         if (path->slots[0] == 0)
3136                 goto out;
3137
3138         path->slots[0]--;
3139         leaf = path->nodes[0];
3140         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3141
3142         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3143                 goto out;
3144
3145         ret = 1;
3146         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3147 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3148         if (item_size < sizeof(*ei)) {
3149                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3150                 goto out;
3151         }
3152 #endif
3153         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3154
3155         if (item_size != sizeof(*ei) +
3156             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3157                 goto out;
3158
3159         if (btrfs_extent_generation(leaf, ei) <=
3160             btrfs_root_last_snapshot(&root->root_item))
3161                 goto out;
3162
3163         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3164         if (btrfs_extent_inline_ref_type(leaf, iref) !=
3165             BTRFS_EXTENT_DATA_REF_KEY)
3166                 goto out;
3167
3168         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3169         if (btrfs_extent_refs(leaf, ei) !=
3170             btrfs_extent_data_ref_count(leaf, ref) ||
3171             btrfs_extent_data_ref_root(leaf, ref) !=
3172             root->root_key.objectid ||
3173             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3174             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3175                 goto out;
3176
3177         ret = 0;
3178 out:
3179         return ret;
3180 }
3181
3182 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
3183                           u64 bytenr)
3184 {
3185         struct btrfs_path *path;
3186         int ret;
3187         int ret2;
3188
3189         path = btrfs_alloc_path();
3190         if (!path)
3191                 return -ENOENT;
3192
3193         do {
3194                 ret = check_committed_ref(root, path, objectid,
3195                                           offset, bytenr);
3196                 if (ret && ret != -ENOENT)
3197                         goto out;
3198
3199                 ret2 = check_delayed_ref(root, path, objectid,
3200                                          offset, bytenr);
3201         } while (ret2 == -EAGAIN);
3202
3203         if (ret2 && ret2 != -ENOENT) {
3204                 ret = ret2;
3205                 goto out;
3206         }
3207
3208         if (ret != -ENOENT || ret2 != -ENOENT)
3209                 ret = 0;
3210 out:
3211         btrfs_free_path(path);
3212         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3213                 WARN_ON(ret > 0);
3214         return ret;
3215 }
3216
3217 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3218                            struct btrfs_root *root,
3219                            struct extent_buffer *buf,
3220                            int full_backref, int inc)
3221 {
3222         struct btrfs_fs_info *fs_info = root->fs_info;
3223         u64 bytenr;
3224         u64 num_bytes;
3225         u64 parent;
3226         u64 ref_root;
3227         u32 nritems;
3228         struct btrfs_key key;
3229         struct btrfs_file_extent_item *fi;
3230         int i;
3231         int level;
3232         int ret = 0;
3233         int (*process_func)(struct btrfs_trans_handle *,
3234                             struct btrfs_fs_info *,
3235                             u64, u64, u64, u64, u64, u64);
3236
3237
3238         if (btrfs_is_testing(fs_info))
3239                 return 0;
3240
3241         ref_root = btrfs_header_owner(buf);
3242         nritems = btrfs_header_nritems(buf);
3243         level = btrfs_header_level(buf);
3244
3245         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3246                 return 0;
3247
3248         if (inc)
3249                 process_func = btrfs_inc_extent_ref;
3250         else
3251                 process_func = btrfs_free_extent;
3252
3253         if (full_backref)
3254                 parent = buf->start;
3255         else
3256                 parent = 0;
3257
3258         for (i = 0; i < nritems; i++) {
3259                 if (level == 0) {
3260                         btrfs_item_key_to_cpu(buf, &key, i);
3261                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3262                                 continue;
3263                         fi = btrfs_item_ptr(buf, i,
3264                                             struct btrfs_file_extent_item);
3265                         if (btrfs_file_extent_type(buf, fi) ==
3266                             BTRFS_FILE_EXTENT_INLINE)
3267                                 continue;
3268                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3269                         if (bytenr == 0)
3270                                 continue;
3271
3272                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3273                         key.offset -= btrfs_file_extent_offset(buf, fi);
3274                         ret = process_func(trans, fs_info, bytenr, num_bytes,
3275                                            parent, ref_root, key.objectid,
3276                                            key.offset);
3277                         if (ret)
3278                                 goto fail;
3279                 } else {
3280                         bytenr = btrfs_node_blockptr(buf, i);
3281                         num_bytes = fs_info->nodesize;
3282                         ret = process_func(trans, fs_info, bytenr, num_bytes,
3283                                            parent, ref_root, level - 1, 0);
3284                         if (ret)
3285                                 goto fail;
3286                 }
3287         }
3288         return 0;
3289 fail:
3290         return ret;
3291 }
3292
3293 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3294                   struct extent_buffer *buf, int full_backref)
3295 {
3296         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3297 }
3298
3299 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3300                   struct extent_buffer *buf, int full_backref)
3301 {
3302         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3303 }
3304
3305 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3306                                  struct btrfs_fs_info *fs_info,
3307                                  struct btrfs_path *path,
3308                                  struct btrfs_block_group_cache *cache)
3309 {
3310         int ret;
3311         struct btrfs_root *extent_root = fs_info->extent_root;
3312         unsigned long bi;
3313         struct extent_buffer *leaf;
3314
3315         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3316         if (ret) {
3317                 if (ret > 0)
3318                         ret = -ENOENT;
3319                 goto fail;
3320         }
3321
3322         leaf = path->nodes[0];
3323         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3324         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3325         btrfs_mark_buffer_dirty(leaf);
3326 fail:
3327         btrfs_release_path(path);
3328         return ret;
3329
3330 }
3331
3332 static struct btrfs_block_group_cache *
3333 next_block_group(struct btrfs_fs_info *fs_info,
3334                  struct btrfs_block_group_cache *cache)
3335 {
3336         struct rb_node *node;
3337
3338         spin_lock(&fs_info->block_group_cache_lock);
3339
3340         /* If our block group was removed, we need a full search. */
3341         if (RB_EMPTY_NODE(&cache->cache_node)) {
3342                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3343
3344                 spin_unlock(&fs_info->block_group_cache_lock);
3345                 btrfs_put_block_group(cache);
3346                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
3347         }
3348         node = rb_next(&cache->cache_node);
3349         btrfs_put_block_group(cache);
3350         if (node) {
3351                 cache = rb_entry(node, struct btrfs_block_group_cache,
3352                                  cache_node);
3353                 btrfs_get_block_group(cache);
3354         } else
3355                 cache = NULL;
3356         spin_unlock(&fs_info->block_group_cache_lock);
3357         return cache;
3358 }
3359
3360 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3361                             struct btrfs_trans_handle *trans,
3362                             struct btrfs_path *path)
3363 {
3364         struct btrfs_fs_info *fs_info = block_group->fs_info;
3365         struct btrfs_root *root = fs_info->tree_root;
3366         struct inode *inode = NULL;
3367         u64 alloc_hint = 0;
3368         int dcs = BTRFS_DC_ERROR;
3369         u64 num_pages = 0;
3370         int retries = 0;
3371         int ret = 0;
3372
3373         /*
3374          * If this block group is smaller than 100 megs don't bother caching the
3375          * block group.
3376          */
3377         if (block_group->key.offset < (100 * SZ_1M)) {
3378                 spin_lock(&block_group->lock);
3379                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3380                 spin_unlock(&block_group->lock);
3381                 return 0;
3382         }
3383
3384         if (trans->aborted)
3385                 return 0;
3386 again:
3387         inode = lookup_free_space_inode(fs_info, block_group, path);
3388         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3389                 ret = PTR_ERR(inode);
3390                 btrfs_release_path(path);
3391                 goto out;
3392         }
3393
3394         if (IS_ERR(inode)) {
3395                 BUG_ON(retries);
3396                 retries++;
3397
3398                 if (block_group->ro)
3399                         goto out_free;
3400
3401                 ret = create_free_space_inode(fs_info, trans, block_group,
3402                                               path);
3403                 if (ret)
3404                         goto out_free;
3405                 goto again;
3406         }
3407
3408         /* We've already setup this transaction, go ahead and exit */
3409         if (block_group->cache_generation == trans->transid &&
3410             i_size_read(inode)) {
3411                 dcs = BTRFS_DC_SETUP;
3412                 goto out_put;
3413         }
3414
3415         /*
3416          * We want to set the generation to 0, that way if anything goes wrong
3417          * from here on out we know not to trust this cache when we load up next
3418          * time.
3419          */
3420         BTRFS_I(inode)->generation = 0;
3421         ret = btrfs_update_inode(trans, root, inode);
3422         if (ret) {
3423                 /*
3424                  * So theoretically we could recover from this, simply set the
3425                  * super cache generation to 0 so we know to invalidate the
3426                  * cache, but then we'd have to keep track of the block groups
3427                  * that fail this way so we know we _have_ to reset this cache
3428                  * before the next commit or risk reading stale cache.  So to
3429                  * limit our exposure to horrible edge cases lets just abort the
3430                  * transaction, this only happens in really bad situations
3431                  * anyway.
3432                  */
3433                 btrfs_abort_transaction(trans, ret);
3434                 goto out_put;
3435         }
3436         WARN_ON(ret);
3437
3438         if (i_size_read(inode) > 0) {
3439                 ret = btrfs_check_trunc_cache_free_space(fs_info,
3440                                         &fs_info->global_block_rsv);
3441                 if (ret)
3442                         goto out_put;
3443
3444                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3445                 if (ret)
3446                         goto out_put;
3447         }
3448
3449         spin_lock(&block_group->lock);
3450         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3451             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3452                 /*
3453                  * don't bother trying to write stuff out _if_
3454                  * a) we're not cached,
3455                  * b) we're with nospace_cache mount option,
3456                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
3457                  */
3458                 dcs = BTRFS_DC_WRITTEN;
3459                 spin_unlock(&block_group->lock);
3460                 goto out_put;
3461         }
3462         spin_unlock(&block_group->lock);
3463
3464         /*
3465          * We hit an ENOSPC when setting up the cache in this transaction, just
3466          * skip doing the setup, we've already cleared the cache so we're safe.
3467          */
3468         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3469                 ret = -ENOSPC;
3470                 goto out_put;
3471         }
3472
3473         /*
3474          * Try to preallocate enough space based on how big the block group is.
3475          * Keep in mind this has to include any pinned space which could end up
3476          * taking up quite a bit since it's not folded into the other space
3477          * cache.
3478          */
3479         num_pages = div_u64(block_group->key.offset, SZ_256M);
3480         if (!num_pages)
3481                 num_pages = 1;
3482
3483         num_pages *= 16;
3484         num_pages *= PAGE_SIZE;
3485
3486         ret = btrfs_check_data_free_space(inode, 0, num_pages);
3487         if (ret)
3488                 goto out_put;
3489
3490         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3491                                               num_pages, num_pages,
3492                                               &alloc_hint);
3493         /*
3494          * Our cache requires contiguous chunks so that we don't modify a bunch
3495          * of metadata or split extents when writing the cache out, which means
3496          * we can enospc if we are heavily fragmented in addition to just normal
3497          * out of space conditions.  So if we hit this just skip setting up any
3498          * other block groups for this transaction, maybe we'll unpin enough
3499          * space the next time around.
3500          */
3501         if (!ret)
3502                 dcs = BTRFS_DC_SETUP;
3503         else if (ret == -ENOSPC)
3504                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3505
3506 out_put:
3507         iput(inode);
3508 out_free:
3509         btrfs_release_path(path);
3510 out:
3511         spin_lock(&block_group->lock);
3512         if (!ret && dcs == BTRFS_DC_SETUP)
3513                 block_group->cache_generation = trans->transid;
3514         block_group->disk_cache_state = dcs;
3515         spin_unlock(&block_group->lock);
3516
3517         return ret;
3518 }
3519
3520 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3521                             struct btrfs_fs_info *fs_info)
3522 {
3523         struct btrfs_block_group_cache *cache, *tmp;
3524         struct btrfs_transaction *cur_trans = trans->transaction;
3525         struct btrfs_path *path;
3526
3527         if (list_empty(&cur_trans->dirty_bgs) ||
3528             !btrfs_test_opt(fs_info, SPACE_CACHE))
3529                 return 0;
3530
3531         path = btrfs_alloc_path();
3532         if (!path)
3533                 return -ENOMEM;
3534
3535         /* Could add new block groups, use _safe just in case */
3536         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3537                                  dirty_list) {
3538                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3539                         cache_save_setup(cache, trans, path);
3540         }
3541
3542         btrfs_free_path(path);
3543         return 0;
3544 }
3545
3546 /*
3547  * transaction commit does final block group cache writeback during a
3548  * critical section where nothing is allowed to change the FS.  This is
3549  * required in order for the cache to actually match the block group,
3550  * but can introduce a lot of latency into the commit.
3551  *
3552  * So, btrfs_start_dirty_block_groups is here to kick off block group
3553  * cache IO.  There's a chance we'll have to redo some of it if the
3554  * block group changes again during the commit, but it greatly reduces
3555  * the commit latency by getting rid of the easy block groups while
3556  * we're still allowing others to join the commit.
3557  */
3558 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3559                                    struct btrfs_fs_info *fs_info)
3560 {
3561         struct btrfs_block_group_cache *cache;
3562         struct btrfs_transaction *cur_trans = trans->transaction;
3563         int ret = 0;
3564         int should_put;
3565         struct btrfs_path *path = NULL;
3566         LIST_HEAD(dirty);
3567         struct list_head *io = &cur_trans->io_bgs;
3568         int num_started = 0;
3569         int loops = 0;
3570
3571         spin_lock(&cur_trans->dirty_bgs_lock);
3572         if (list_empty(&cur_trans->dirty_bgs)) {
3573                 spin_unlock(&cur_trans->dirty_bgs_lock);
3574                 return 0;
3575         }
3576         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3577         spin_unlock(&cur_trans->dirty_bgs_lock);
3578
3579 again:
3580         /*
3581          * make sure all the block groups on our dirty list actually
3582          * exist
3583          */
3584         btrfs_create_pending_block_groups(trans, fs_info);
3585
3586         if (!path) {
3587                 path = btrfs_alloc_path();
3588                 if (!path)
3589                         return -ENOMEM;
3590         }
3591
3592         /*
3593          * cache_write_mutex is here only to save us from balance or automatic
3594          * removal of empty block groups deleting this block group while we are
3595          * writing out the cache
3596          */
3597         mutex_lock(&trans->transaction->cache_write_mutex);
3598         while (!list_empty(&dirty)) {
3599                 cache = list_first_entry(&dirty,
3600                                          struct btrfs_block_group_cache,
3601                                          dirty_list);
3602                 /*
3603                  * this can happen if something re-dirties a block
3604                  * group that is already under IO.  Just wait for it to
3605                  * finish and then do it all again
3606                  */
3607                 if (!list_empty(&cache->io_list)) {
3608                         list_del_init(&cache->io_list);
3609                         btrfs_wait_cache_io(trans, cache, path);
3610                         btrfs_put_block_group(cache);
3611                 }
3612
3613
3614                 /*
3615                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3616                  * if it should update the cache_state.  Don't delete
3617                  * until after we wait.
3618                  *
3619                  * Since we're not running in the commit critical section
3620                  * we need the dirty_bgs_lock to protect from update_block_group
3621                  */
3622                 spin_lock(&cur_trans->dirty_bgs_lock);
3623                 list_del_init(&cache->dirty_list);
3624                 spin_unlock(&cur_trans->dirty_bgs_lock);
3625
3626                 should_put = 1;
3627
3628                 cache_save_setup(cache, trans, path);
3629
3630                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3631                         cache->io_ctl.inode = NULL;
3632                         ret = btrfs_write_out_cache(fs_info, trans,
3633                                                     cache, path);
3634                         if (ret == 0 && cache->io_ctl.inode) {
3635                                 num_started++;
3636                                 should_put = 0;
3637
3638                                 /*
3639                                  * the cache_write_mutex is protecting
3640                                  * the io_list
3641                                  */
3642                                 list_add_tail(&cache->io_list, io);
3643                         } else {
3644                                 /*
3645                                  * if we failed to write the cache, the
3646                                  * generation will be bad and life goes on
3647                                  */
3648                                 ret = 0;
3649                         }
3650                 }
3651                 if (!ret) {
3652                         ret = write_one_cache_group(trans, fs_info,
3653                                                     path, cache);
3654                         /*
3655                          * Our block group might still be attached to the list
3656                          * of new block groups in the transaction handle of some
3657                          * other task (struct btrfs_trans_handle->new_bgs). This
3658                          * means its block group item isn't yet in the extent
3659                          * tree. If this happens ignore the error, as we will
3660                          * try again later in the critical section of the
3661                          * transaction commit.
3662                          */
3663                         if (ret == -ENOENT) {
3664                                 ret = 0;
3665                                 spin_lock(&cur_trans->dirty_bgs_lock);
3666                                 if (list_empty(&cache->dirty_list)) {
3667                                         list_add_tail(&cache->dirty_list,
3668                                                       &cur_trans->dirty_bgs);
3669                                         btrfs_get_block_group(cache);
3670                                 }
3671                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3672                         } else if (ret) {
3673                                 btrfs_abort_transaction(trans, ret);
3674                         }
3675                 }
3676
3677                 /* if its not on the io list, we need to put the block group */
3678                 if (should_put)
3679                         btrfs_put_block_group(cache);
3680
3681                 if (ret)
3682                         break;
3683
3684                 /*
3685                  * Avoid blocking other tasks for too long. It might even save
3686                  * us from writing caches for block groups that are going to be
3687                  * removed.
3688                  */
3689                 mutex_unlock(&trans->transaction->cache_write_mutex);
3690                 mutex_lock(&trans->transaction->cache_write_mutex);
3691         }
3692         mutex_unlock(&trans->transaction->cache_write_mutex);
3693
3694         /*
3695          * go through delayed refs for all the stuff we've just kicked off
3696          * and then loop back (just once)
3697          */
3698         ret = btrfs_run_delayed_refs(trans, fs_info, 0);
3699         if (!ret && loops == 0) {
3700                 loops++;
3701                 spin_lock(&cur_trans->dirty_bgs_lock);
3702                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3703                 /*
3704                  * dirty_bgs_lock protects us from concurrent block group
3705                  * deletes too (not just cache_write_mutex).
3706                  */
3707                 if (!list_empty(&dirty)) {
3708                         spin_unlock(&cur_trans->dirty_bgs_lock);
3709                         goto again;
3710                 }
3711                 spin_unlock(&cur_trans->dirty_bgs_lock);
3712         } else if (ret < 0) {
3713                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3714         }
3715
3716         btrfs_free_path(path);
3717         return ret;
3718 }
3719
3720 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3721                                    struct btrfs_fs_info *fs_info)
3722 {
3723         struct btrfs_block_group_cache *cache;
3724         struct btrfs_transaction *cur_trans = trans->transaction;
3725         int ret = 0;
3726         int should_put;
3727         struct btrfs_path *path;
3728         struct list_head *io = &cur_trans->io_bgs;
3729         int num_started = 0;
3730
3731         path = btrfs_alloc_path();
3732         if (!path)
3733                 return -ENOMEM;
3734
3735         /*
3736          * Even though we are in the critical section of the transaction commit,
3737          * we can still have concurrent tasks adding elements to this
3738          * transaction's list of dirty block groups. These tasks correspond to
3739          * endio free space workers started when writeback finishes for a
3740          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3741          * allocate new block groups as a result of COWing nodes of the root
3742          * tree when updating the free space inode. The writeback for the space
3743          * caches is triggered by an earlier call to
3744          * btrfs_start_dirty_block_groups() and iterations of the following
3745          * loop.
3746          * Also we want to do the cache_save_setup first and then run the
3747          * delayed refs to make sure we have the best chance at doing this all
3748          * in one shot.
3749          */
3750         spin_lock(&cur_trans->dirty_bgs_lock);
3751         while (!list_empty(&cur_trans->dirty_bgs)) {
3752                 cache = list_first_entry(&cur_trans->dirty_bgs,
3753                                          struct btrfs_block_group_cache,
3754                                          dirty_list);
3755
3756                 /*
3757                  * this can happen if cache_save_setup re-dirties a block
3758                  * group that is already under IO.  Just wait for it to
3759                  * finish and then do it all again
3760                  */
3761                 if (!list_empty(&cache->io_list)) {
3762                         spin_unlock(&cur_trans->dirty_bgs_lock);
3763                         list_del_init(&cache->io_list);
3764                         btrfs_wait_cache_io(trans, cache, path);
3765                         btrfs_put_block_group(cache);
3766                         spin_lock(&cur_trans->dirty_bgs_lock);
3767                 }
3768
3769                 /*
3770                  * don't remove from the dirty list until after we've waited
3771                  * on any pending IO
3772                  */
3773                 list_del_init(&cache->dirty_list);
3774                 spin_unlock(&cur_trans->dirty_bgs_lock);
3775                 should_put = 1;
3776
3777                 cache_save_setup(cache, trans, path);
3778
3779                 if (!ret)
3780                         ret = btrfs_run_delayed_refs(trans, fs_info,
3781                                                      (unsigned long) -1);
3782
3783                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3784                         cache->io_ctl.inode = NULL;
3785                         ret = btrfs_write_out_cache(fs_info, trans,
3786                                                     cache, path);
3787                         if (ret == 0 && cache->io_ctl.inode) {
3788                                 num_started++;
3789                                 should_put = 0;
3790                                 list_add_tail(&cache->io_list, io);
3791                         } else {
3792                                 /*
3793                                  * if we failed to write the cache, the
3794                                  * generation will be bad and life goes on
3795                                  */
3796                                 ret = 0;
3797                         }
3798                 }
3799                 if (!ret) {
3800                         ret = write_one_cache_group(trans, fs_info,
3801                                                     path, cache);
3802                         /*
3803                          * One of the free space endio workers might have
3804                          * created a new block group while updating a free space
3805                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3806                          * and hasn't released its transaction handle yet, in
3807                          * which case the new block group is still attached to
3808                          * its transaction handle and its creation has not
3809                          * finished yet (no block group item in the extent tree
3810                          * yet, etc). If this is the case, wait for all free
3811                          * space endio workers to finish and retry. This is a
3812                          * a very rare case so no need for a more efficient and
3813                          * complex approach.
3814                          */
3815                         if (ret == -ENOENT) {
3816                                 wait_event(cur_trans->writer_wait,
3817                                    atomic_read(&cur_trans->num_writers) == 1);
3818                                 ret = write_one_cache_group(trans, fs_info,
3819                                                             path, cache);
3820                         }
3821                         if (ret)
3822                                 btrfs_abort_transaction(trans, ret);
3823                 }
3824
3825                 /* if its not on the io list, we need to put the block group */
3826                 if (should_put)
3827                         btrfs_put_block_group(cache);
3828                 spin_lock(&cur_trans->dirty_bgs_lock);
3829         }
3830         spin_unlock(&cur_trans->dirty_bgs_lock);
3831
3832         while (!list_empty(io)) {
3833                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3834                                          io_list);
3835                 list_del_init(&cache->io_list);
3836                 btrfs_wait_cache_io(trans, cache, path);
3837                 btrfs_put_block_group(cache);
3838         }
3839
3840         btrfs_free_path(path);
3841         return ret;
3842 }
3843
3844 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
3845 {
3846         struct btrfs_block_group_cache *block_group;
3847         int readonly = 0;
3848
3849         block_group = btrfs_lookup_block_group(fs_info, bytenr);
3850         if (!block_group || block_group->ro)
3851                 readonly = 1;
3852         if (block_group)
3853                 btrfs_put_block_group(block_group);
3854         return readonly;
3855 }
3856
3857 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3858 {
3859         struct btrfs_block_group_cache *bg;
3860         bool ret = true;
3861
3862         bg = btrfs_lookup_block_group(fs_info, bytenr);
3863         if (!bg)
3864                 return false;
3865
3866         spin_lock(&bg->lock);
3867         if (bg->ro)
3868                 ret = false;
3869         else
3870                 atomic_inc(&bg->nocow_writers);
3871         spin_unlock(&bg->lock);
3872
3873         /* no put on block group, done by btrfs_dec_nocow_writers */
3874         if (!ret)
3875                 btrfs_put_block_group(bg);
3876
3877         return ret;
3878
3879 }
3880
3881 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3882 {
3883         struct btrfs_block_group_cache *bg;
3884
3885         bg = btrfs_lookup_block_group(fs_info, bytenr);
3886         ASSERT(bg);
3887         if (atomic_dec_and_test(&bg->nocow_writers))
3888                 wake_up_atomic_t(&bg->nocow_writers);
3889         /*
3890          * Once for our lookup and once for the lookup done by a previous call
3891          * to btrfs_inc_nocow_writers()
3892          */
3893         btrfs_put_block_group(bg);
3894         btrfs_put_block_group(bg);
3895 }
3896
3897 static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a)
3898 {
3899         schedule();
3900         return 0;
3901 }
3902
3903 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3904 {
3905         wait_on_atomic_t(&bg->nocow_writers,
3906                          btrfs_wait_nocow_writers_atomic_t,
3907                          TASK_UNINTERRUPTIBLE);
3908 }
3909
3910 static const char *alloc_name(u64 flags)
3911 {
3912         switch (flags) {
3913         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3914                 return "mixed";
3915         case BTRFS_BLOCK_GROUP_METADATA:
3916                 return "metadata";
3917         case BTRFS_BLOCK_GROUP_DATA:
3918                 return "data";
3919         case BTRFS_BLOCK_GROUP_SYSTEM:
3920                 return "system";
3921         default:
3922                 WARN_ON(1);
3923                 return "invalid-combination";
3924         };
3925 }
3926
3927 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3928                              u64 total_bytes, u64 bytes_used,
3929                              u64 bytes_readonly,
3930                              struct btrfs_space_info **space_info)
3931 {
3932         struct btrfs_space_info *found;
3933         int i;
3934         int factor;
3935         int ret;
3936
3937         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3938                      BTRFS_BLOCK_GROUP_RAID10))
3939                 factor = 2;
3940         else
3941                 factor = 1;
3942
3943         found = __find_space_info(info, flags);
3944         if (found) {
3945                 spin_lock(&found->lock);
3946                 found->total_bytes += total_bytes;
3947                 found->disk_total += total_bytes * factor;
3948                 found->bytes_used += bytes_used;
3949                 found->disk_used += bytes_used * factor;
3950                 found->bytes_readonly += bytes_readonly;
3951                 if (total_bytes > 0)
3952                         found->full = 0;
3953                 space_info_add_new_bytes(info, found, total_bytes -
3954                                          bytes_used - bytes_readonly);
3955                 spin_unlock(&found->lock);
3956                 *space_info = found;
3957                 return 0;
3958         }
3959         found = kzalloc(sizeof(*found), GFP_NOFS);
3960         if (!found)
3961                 return -ENOMEM;
3962
3963         ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3964         if (ret) {
3965                 kfree(found);
3966                 return ret;
3967         }
3968
3969         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3970                 INIT_LIST_HEAD(&found->block_groups[i]);
3971         init_rwsem(&found->groups_sem);
3972         spin_lock_init(&found->lock);
3973         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3974         found->total_bytes = total_bytes;
3975         found->disk_total = total_bytes * factor;
3976         found->bytes_used = bytes_used;
3977         found->disk_used = bytes_used * factor;
3978         found->bytes_pinned = 0;
3979         found->bytes_reserved = 0;
3980         found->bytes_readonly = bytes_readonly;
3981         found->bytes_may_use = 0;
3982         found->full = 0;
3983         found->max_extent_size = 0;
3984         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3985         found->chunk_alloc = 0;
3986         found->flush = 0;
3987         init_waitqueue_head(&found->wait);
3988         INIT_LIST_HEAD(&found->ro_bgs);
3989         INIT_LIST_HEAD(&found->tickets);
3990         INIT_LIST_HEAD(&found->priority_tickets);
3991
3992         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3993                                     info->space_info_kobj, "%s",
3994                                     alloc_name(found->flags));
3995         if (ret) {
3996                 percpu_counter_destroy(&found->total_bytes_pinned);
3997                 kfree(found);
3998                 return ret;
3999         }
4000
4001         *space_info = found;
4002         list_add_rcu(&found->list, &info->space_info);
4003         if (flags & BTRFS_BLOCK_GROUP_DATA)
4004                 info->data_sinfo = found;
4005
4006         return ret;
4007 }
4008
4009 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
4010 {
4011         u64 extra_flags = chunk_to_extended(flags) &
4012                                 BTRFS_EXTENDED_PROFILE_MASK;
4013
4014         write_seqlock(&fs_info->profiles_lock);
4015         if (flags & BTRFS_BLOCK_GROUP_DATA)
4016                 fs_info->avail_data_alloc_bits |= extra_flags;
4017         if (flags & BTRFS_BLOCK_GROUP_METADATA)
4018                 fs_info->avail_metadata_alloc_bits |= extra_flags;
4019         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4020                 fs_info->avail_system_alloc_bits |= extra_flags;
4021         write_sequnlock(&fs_info->profiles_lock);
4022 }
4023
4024 /*
4025  * returns target flags in extended format or 0 if restripe for this
4026  * chunk_type is not in progress
4027  *
4028  * should be called with either volume_mutex or balance_lock held
4029  */
4030 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4031 {
4032         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4033         u64 target = 0;
4034
4035         if (!bctl)
4036                 return 0;
4037
4038         if (flags & BTRFS_BLOCK_GROUP_DATA &&
4039             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4040                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4041         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4042                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4043                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4044         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4045                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4046                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4047         }
4048
4049         return target;
4050 }
4051
4052 /*
4053  * @flags: available profiles in extended format (see ctree.h)
4054  *
4055  * Returns reduced profile in chunk format.  If profile changing is in
4056  * progress (either running or paused) picks the target profile (if it's
4057  * already available), otherwise falls back to plain reducing.
4058  */
4059 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
4060 {
4061         u64 num_devices = fs_info->fs_devices->rw_devices;
4062         u64 target;
4063         u64 raid_type;
4064         u64 allowed = 0;
4065
4066         /*
4067          * see if restripe for this chunk_type is in progress, if so
4068          * try to reduce to the target profile
4069          */
4070         spin_lock(&fs_info->balance_lock);
4071         target = get_restripe_target(fs_info, flags);
4072         if (target) {
4073                 /* pick target profile only if it's already available */
4074                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4075                         spin_unlock(&fs_info->balance_lock);
4076                         return extended_to_chunk(target);
4077                 }
4078         }
4079         spin_unlock(&fs_info->balance_lock);
4080
4081         /* First, mask out the RAID levels which aren't possible */
4082         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4083                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4084                         allowed |= btrfs_raid_group[raid_type];
4085         }
4086         allowed &= flags;
4087
4088         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4089                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4090         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4091                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4092         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4093                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4094         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4095                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4096         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4097                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4098
4099         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4100
4101         return extended_to_chunk(flags | allowed);
4102 }
4103
4104 static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
4105 {
4106         unsigned seq;
4107         u64 flags;
4108
4109         do {
4110                 flags = orig_flags;
4111                 seq = read_seqbegin(&fs_info->profiles_lock);
4112
4113                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4114                         flags |= fs_info->avail_data_alloc_bits;
4115                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4116                         flags |= fs_info->avail_system_alloc_bits;
4117                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4118                         flags |= fs_info->avail_metadata_alloc_bits;
4119         } while (read_seqretry(&fs_info->profiles_lock, seq));
4120
4121         return btrfs_reduce_alloc_profile(fs_info, flags);
4122 }
4123
4124 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
4125 {
4126         struct btrfs_fs_info *fs_info = root->fs_info;
4127         u64 flags;
4128         u64 ret;
4129
4130         if (data)
4131                 flags = BTRFS_BLOCK_GROUP_DATA;
4132         else if (root == fs_info->chunk_root)
4133                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4134         else
4135                 flags = BTRFS_BLOCK_GROUP_METADATA;
4136
4137         ret = get_alloc_profile(fs_info, flags);
4138         return ret;
4139 }
4140
4141 static u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
4142                                  bool may_use_included)
4143 {
4144         ASSERT(s_info);
4145         return s_info->bytes_used + s_info->bytes_reserved +
4146                 s_info->bytes_pinned + s_info->bytes_readonly +
4147                 (may_use_included ? s_info->bytes_may_use : 0);
4148 }
4149
4150 int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes)
4151 {
4152         struct btrfs_space_info *data_sinfo;
4153         struct btrfs_root *root = inode->root;
4154         struct btrfs_fs_info *fs_info = root->fs_info;
4155         u64 used;
4156         int ret = 0;
4157         int need_commit = 2;
4158         int have_pinned_space;
4159
4160         /* make sure bytes are sectorsize aligned */
4161         bytes = ALIGN(bytes, fs_info->sectorsize);
4162
4163         if (btrfs_is_free_space_inode(inode)) {
4164                 need_commit = 0;
4165                 ASSERT(current->journal_info);
4166         }
4167
4168         data_sinfo = fs_info->data_sinfo;
4169         if (!data_sinfo)
4170                 goto alloc;
4171
4172 again:
4173         /* make sure we have enough space to handle the data first */
4174         spin_lock(&data_sinfo->lock);
4175         used = btrfs_space_info_used(data_sinfo, true);
4176
4177         if (used + bytes > data_sinfo->total_bytes) {
4178                 struct btrfs_trans_handle *trans;
4179
4180                 /*
4181                  * if we don't have enough free bytes in this space then we need
4182                  * to alloc a new chunk.
4183                  */
4184                 if (!data_sinfo->full) {
4185                         u64 alloc_target;
4186
4187                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4188                         spin_unlock(&data_sinfo->lock);
4189 alloc:
4190                         alloc_target = btrfs_get_alloc_profile(root, 1);
4191                         /*
4192                          * It is ugly that we don't call nolock join
4193                          * transaction for the free space inode case here.
4194                          * But it is safe because we only do the data space
4195                          * reservation for the free space cache in the
4196                          * transaction context, the common join transaction
4197                          * just increase the counter of the current transaction
4198                          * handler, doesn't try to acquire the trans_lock of
4199                          * the fs.
4200                          */
4201                         trans = btrfs_join_transaction(root);
4202                         if (IS_ERR(trans))
4203                                 return PTR_ERR(trans);
4204
4205                         ret = do_chunk_alloc(trans, fs_info, alloc_target,
4206                                              CHUNK_ALLOC_NO_FORCE);
4207                         btrfs_end_transaction(trans);
4208                         if (ret < 0) {
4209                                 if (ret != -ENOSPC)
4210                                         return ret;
4211                                 else {
4212                                         have_pinned_space = 1;
4213                                         goto commit_trans;
4214                                 }
4215                         }
4216
4217                         if (!data_sinfo)
4218                                 data_sinfo = fs_info->data_sinfo;
4219
4220                         goto again;
4221                 }
4222
4223                 /*
4224                  * If we don't have enough pinned space to deal with this
4225                  * allocation, and no removed chunk in current transaction,
4226                  * don't bother committing the transaction.
4227                  */
4228                 have_pinned_space = percpu_counter_compare(
4229                         &data_sinfo->total_bytes_pinned,
4230                         used + bytes - data_sinfo->total_bytes);
4231                 spin_unlock(&data_sinfo->lock);
4232
4233                 /* commit the current transaction and try again */
4234 commit_trans:
4235                 if (need_commit &&
4236                     !atomic_read(&fs_info->open_ioctl_trans)) {
4237                         need_commit--;
4238
4239                         if (need_commit > 0) {
4240                                 btrfs_start_delalloc_roots(fs_info, 0, -1);
4241                                 btrfs_wait_ordered_roots(fs_info, -1, 0,
4242                                                          (u64)-1);
4243                         }
4244
4245                         trans = btrfs_join_transaction(root);
4246                         if (IS_ERR(trans))
4247                                 return PTR_ERR(trans);
4248                         if (have_pinned_space >= 0 ||
4249                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4250                                      &trans->transaction->flags) ||
4251                             need_commit > 0) {
4252                                 ret = btrfs_commit_transaction(trans);
4253                                 if (ret)
4254                                         return ret;
4255                                 /*
4256                                  * The cleaner kthread might still be doing iput
4257                                  * operations. Wait for it to finish so that
4258                                  * more space is released.
4259                                  */
4260                                 mutex_lock(&fs_info->cleaner_delayed_iput_mutex);
4261                                 mutex_unlock(&fs_info->cleaner_delayed_iput_mutex);
4262                                 goto again;
4263                         } else {
4264                                 btrfs_end_transaction(trans);
4265                         }
4266                 }
4267
4268                 trace_btrfs_space_reservation(fs_info,
4269                                               "space_info:enospc",
4270                                               data_sinfo->flags, bytes, 1);
4271                 return -ENOSPC;
4272         }
4273         data_sinfo->bytes_may_use += bytes;
4274         trace_btrfs_space_reservation(fs_info, "space_info",
4275                                       data_sinfo->flags, bytes, 1);
4276         spin_unlock(&data_sinfo->lock);
4277
4278         return ret;
4279 }
4280
4281 /*
4282  * New check_data_free_space() with ability for precious data reservation
4283  * Will replace old btrfs_check_data_free_space(), but for patch split,
4284  * add a new function first and then replace it.
4285  */
4286 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4287 {
4288         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4289         int ret;
4290
4291         /* align the range */
4292         len = round_up(start + len, fs_info->sectorsize) -
4293               round_down(start, fs_info->sectorsize);
4294         start = round_down(start, fs_info->sectorsize);
4295
4296         ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), len);
4297         if (ret < 0)
4298                 return ret;
4299
4300         /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4301         ret = btrfs_qgroup_reserve_data(inode, start, len);
4302         if (ret)
4303                 btrfs_free_reserved_data_space_noquota(inode, start, len);
4304         return ret;
4305 }
4306
4307 /*
4308  * Called if we need to clear a data reservation for this inode
4309  * Normally in a error case.
4310  *
4311  * This one will *NOT* use accurate qgroup reserved space API, just for case
4312  * which we can't sleep and is sure it won't affect qgroup reserved space.
4313  * Like clear_bit_hook().
4314  */
4315 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4316                                             u64 len)
4317 {
4318         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4319         struct btrfs_space_info *data_sinfo;
4320
4321         /* Make sure the range is aligned to sectorsize */
4322         len = round_up(start + len, fs_info->sectorsize) -
4323               round_down(start, fs_info->sectorsize);
4324         start = round_down(start, fs_info->sectorsize);
4325
4326         data_sinfo = fs_info->data_sinfo;
4327         spin_lock(&data_sinfo->lock);
4328         if (WARN_ON(data_sinfo->bytes_may_use < len))
4329                 data_sinfo->bytes_may_use = 0;
4330         else
4331                 data_sinfo->bytes_may_use -= len;
4332         trace_btrfs_space_reservation(fs_info, "space_info",
4333                                       data_sinfo->flags, len, 0);
4334         spin_unlock(&data_sinfo->lock);
4335 }
4336
4337 /*
4338  * Called if we need to clear a data reservation for this inode
4339  * Normally in a error case.
4340  *
4341  * This one will handle the per-inode data rsv map for accurate reserved
4342  * space framework.
4343  */
4344 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4345 {
4346         struct btrfs_root *root = BTRFS_I(inode)->root;
4347
4348         /* Make sure the range is aligned to sectorsize */
4349         len = round_up(start + len, root->fs_info->sectorsize) -
4350               round_down(start, root->fs_info->sectorsize);
4351         start = round_down(start, root->fs_info->sectorsize);
4352
4353         btrfs_free_reserved_data_space_noquota(inode, start, len);
4354         btrfs_qgroup_free_data(inode, start, len);
4355 }
4356
4357 static void force_metadata_allocation(struct btrfs_fs_info *info)
4358 {
4359         struct list_head *head = &info->space_info;
4360         struct btrfs_space_info *found;
4361
4362         rcu_read_lock();
4363         list_for_each_entry_rcu(found, head, list) {
4364                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4365                         found->force_alloc = CHUNK_ALLOC_FORCE;
4366         }
4367         rcu_read_unlock();
4368 }
4369
4370 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4371 {
4372         return (global->size << 1);
4373 }
4374
4375 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
4376                               struct btrfs_space_info *sinfo, int force)
4377 {
4378         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4379         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4380         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4381         u64 thresh;
4382
4383         if (force == CHUNK_ALLOC_FORCE)
4384                 return 1;
4385
4386         /*
4387          * We need to take into account the global rsv because for all intents
4388          * and purposes it's used space.  Don't worry about locking the
4389          * global_rsv, it doesn't change except when the transaction commits.
4390          */
4391         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4392                 num_allocated += calc_global_rsv_need_space(global_rsv);
4393
4394         /*
4395          * in limited mode, we want to have some free space up to
4396          * about 1% of the FS size.
4397          */
4398         if (force == CHUNK_ALLOC_LIMITED) {
4399                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
4400                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4401
4402                 if (num_bytes - num_allocated < thresh)
4403                         return 1;
4404         }
4405
4406         if (num_allocated + SZ_2M < div_factor(num_bytes, 8))
4407                 return 0;
4408         return 1;
4409 }
4410
4411 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4412 {
4413         u64 num_dev;
4414
4415         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4416                     BTRFS_BLOCK_GROUP_RAID0 |
4417                     BTRFS_BLOCK_GROUP_RAID5 |
4418                     BTRFS_BLOCK_GROUP_RAID6))
4419                 num_dev = fs_info->fs_devices->rw_devices;
4420         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4421                 num_dev = 2;
4422         else
4423                 num_dev = 1;    /* DUP or single */
4424
4425         return num_dev;
4426 }
4427
4428 /*
4429  * If @is_allocation is true, reserve space in the system space info necessary
4430  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4431  * removing a chunk.
4432  */
4433 void check_system_chunk(struct btrfs_trans_handle *trans,
4434                         struct btrfs_fs_info *fs_info, u64 type)
4435 {
4436         struct btrfs_space_info *info;
4437         u64 left;
4438         u64 thresh;
4439         int ret = 0;
4440         u64 num_devs;
4441
4442         /*
4443          * Needed because we can end up allocating a system chunk and for an
4444          * atomic and race free space reservation in the chunk block reserve.
4445          */
4446         ASSERT(mutex_is_locked(&fs_info->chunk_mutex));
4447
4448         info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4449         spin_lock(&info->lock);
4450         left = info->total_bytes - btrfs_space_info_used(info, true);
4451         spin_unlock(&info->lock);
4452
4453         num_devs = get_profile_num_devs(fs_info, type);
4454
4455         /* num_devs device items to update and 1 chunk item to add or remove */
4456         thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
4457                 btrfs_calc_trans_metadata_size(fs_info, 1);
4458
4459         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4460                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4461                            left, thresh, type);
4462                 dump_space_info(fs_info, info, 0, 0);
4463         }
4464
4465         if (left < thresh) {
4466                 u64 flags;
4467
4468                 flags = btrfs_get_alloc_profile(fs_info->chunk_root, 0);
4469                 /*
4470                  * Ignore failure to create system chunk. We might end up not
4471                  * needing it, as we might not need to COW all nodes/leafs from
4472                  * the paths we visit in the chunk tree (they were already COWed
4473                  * or created in the current transaction for example).
4474                  */
4475                 ret = btrfs_alloc_chunk(trans, fs_info, flags);
4476         }
4477
4478         if (!ret) {
4479                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
4480                                           &fs_info->chunk_block_rsv,
4481                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4482                 if (!ret)
4483                         trans->chunk_bytes_reserved += thresh;
4484         }
4485 }
4486
4487 /*
4488  * If force is CHUNK_ALLOC_FORCE:
4489  *    - return 1 if it successfully allocates a chunk,
4490  *    - return errors including -ENOSPC otherwise.
4491  * If force is NOT CHUNK_ALLOC_FORCE:
4492  *    - return 0 if it doesn't need to allocate a new chunk,
4493  *    - return 1 if it successfully allocates a chunk,
4494  *    - return errors including -ENOSPC otherwise.
4495  */
4496 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4497                           struct btrfs_fs_info *fs_info, u64 flags, int force)
4498 {
4499         struct btrfs_space_info *space_info;
4500         int wait_for_alloc = 0;
4501         int ret = 0;
4502
4503         /* Don't re-enter if we're already allocating a chunk */
4504         if (trans->allocating_chunk)
4505                 return -ENOSPC;
4506
4507         space_info = __find_space_info(fs_info, flags);
4508         if (!space_info) {
4509                 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
4510                 BUG_ON(ret); /* -ENOMEM */
4511         }
4512         BUG_ON(!space_info); /* Logic error */
4513
4514 again:
4515         spin_lock(&space_info->lock);
4516         if (force < space_info->force_alloc)
4517                 force = space_info->force_alloc;
4518         if (space_info->full) {
4519                 if (should_alloc_chunk(fs_info, space_info, force))
4520                         ret = -ENOSPC;
4521                 else
4522                         ret = 0;
4523                 spin_unlock(&space_info->lock);
4524                 return ret;
4525         }
4526
4527         if (!should_alloc_chunk(fs_info, space_info, force)) {
4528                 spin_unlock(&space_info->lock);
4529                 return 0;
4530         } else if (space_info->chunk_alloc) {
4531                 wait_for_alloc = 1;
4532         } else {
4533                 space_info->chunk_alloc = 1;
4534         }
4535
4536         spin_unlock(&space_info->lock);
4537
4538         mutex_lock(&fs_info->chunk_mutex);
4539
4540         /*
4541          * The chunk_mutex is held throughout the entirety of a chunk
4542          * allocation, so once we've acquired the chunk_mutex we know that the
4543          * other guy is done and we need to recheck and see if we should
4544          * allocate.
4545          */
4546         if (wait_for_alloc) {
4547                 mutex_unlock(&fs_info->chunk_mutex);
4548                 wait_for_alloc = 0;
4549                 goto again;
4550         }
4551
4552         trans->allocating_chunk = true;
4553
4554         /*
4555          * If we have mixed data/metadata chunks we want to make sure we keep
4556          * allocating mixed chunks instead of individual chunks.
4557          */
4558         if (btrfs_mixed_space_info(space_info))
4559                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4560
4561         /*
4562          * if we're doing a data chunk, go ahead and make sure that
4563          * we keep a reasonable number of metadata chunks allocated in the
4564          * FS as well.
4565          */
4566         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4567                 fs_info->data_chunk_allocations++;
4568                 if (!(fs_info->data_chunk_allocations %
4569                       fs_info->metadata_ratio))
4570                         force_metadata_allocation(fs_info);
4571         }
4572
4573         /*
4574          * Check if we have enough space in SYSTEM chunk because we may need
4575          * to update devices.
4576          */
4577         check_system_chunk(trans, fs_info, flags);
4578
4579         ret = btrfs_alloc_chunk(trans, fs_info, flags);
4580         trans->allocating_chunk = false;
4581
4582         spin_lock(&space_info->lock);
4583         if (ret < 0 && ret != -ENOSPC)
4584                 goto out;
4585         if (ret)
4586                 space_info->full = 1;
4587         else
4588                 ret = 1;
4589
4590         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4591 out:
4592         space_info->chunk_alloc = 0;
4593         spin_unlock(&space_info->lock);
4594         mutex_unlock(&fs_info->chunk_mutex);
4595         /*
4596          * When we allocate a new chunk we reserve space in the chunk block
4597          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4598          * add new nodes/leafs to it if we end up needing to do it when
4599          * inserting the chunk item and updating device items as part of the
4600          * second phase of chunk allocation, performed by
4601          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4602          * large number of new block groups to create in our transaction
4603          * handle's new_bgs list to avoid exhausting the chunk block reserve
4604          * in extreme cases - like having a single transaction create many new
4605          * block groups when starting to write out the free space caches of all
4606          * the block groups that were made dirty during the lifetime of the
4607          * transaction.
4608          */
4609         if (trans->can_flush_pending_bgs &&
4610             trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4611                 btrfs_create_pending_block_groups(trans, fs_info);
4612                 btrfs_trans_release_chunk_metadata(trans);
4613         }
4614         return ret;
4615 }
4616
4617 static int can_overcommit(struct btrfs_root *root,
4618                           struct btrfs_space_info *space_info, u64 bytes,
4619                           enum btrfs_reserve_flush_enum flush)
4620 {
4621         struct btrfs_fs_info *fs_info = root->fs_info;
4622         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4623         u64 profile;
4624         u64 space_size;
4625         u64 avail;
4626         u64 used;
4627
4628         /* Don't overcommit when in mixed mode. */
4629         if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4630                 return 0;
4631
4632         profile = btrfs_get_alloc_profile(root, 0);
4633         used = btrfs_space_info_used(space_info, false);
4634
4635         /*
4636          * We only want to allow over committing if we have lots of actual space
4637          * free, but if we don't have enough space to handle the global reserve
4638          * space then we could end up having a real enospc problem when trying
4639          * to allocate a chunk or some other such important allocation.
4640          */
4641         spin_lock(&global_rsv->lock);
4642         space_size = calc_global_rsv_need_space(global_rsv);
4643         spin_unlock(&global_rsv->lock);
4644         if (used + space_size >= space_info->total_bytes)
4645                 return 0;
4646
4647         used += space_info->bytes_may_use;
4648
4649         spin_lock(&fs_info->free_chunk_lock);
4650         avail = fs_info->free_chunk_space;
4651         spin_unlock(&fs_info->free_chunk_lock);
4652
4653         /*
4654          * If we have dup, raid1 or raid10 then only half of the free
4655          * space is actually useable.  For raid56, the space info used
4656          * doesn't include the parity drive, so we don't have to
4657          * change the math
4658          */
4659         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4660                        BTRFS_BLOCK_GROUP_RAID1 |
4661                        BTRFS_BLOCK_GROUP_RAID10))
4662                 avail >>= 1;
4663
4664         /*
4665          * If we aren't flushing all things, let us overcommit up to
4666          * 1/2th of the space. If we can flush, don't let us overcommit
4667          * too much, let it overcommit up to 1/8 of the space.
4668          */
4669         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4670                 avail >>= 3;
4671         else
4672                 avail >>= 1;
4673
4674         if (used + bytes < space_info->total_bytes + avail)
4675                 return 1;
4676         return 0;
4677 }
4678
4679 static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
4680                                          unsigned long nr_pages, int nr_items)
4681 {
4682         struct super_block *sb = fs_info->sb;
4683
4684         if (down_read_trylock(&sb->s_umount)) {
4685                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4686                 up_read(&sb->s_umount);
4687         } else {
4688                 /*
4689                  * We needn't worry the filesystem going from r/w to r/o though
4690                  * we don't acquire ->s_umount mutex, because the filesystem
4691                  * should guarantee the delalloc inodes list be empty after
4692                  * the filesystem is readonly(all dirty pages are written to
4693                  * the disk).
4694                  */
4695                 btrfs_start_delalloc_roots(fs_info, 0, nr_items);
4696                 if (!current->journal_info)
4697                         btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
4698         }
4699 }
4700
4701 static inline int calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
4702                                         u64 to_reclaim)
4703 {
4704         u64 bytes;
4705         int nr;
4706
4707         bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
4708         nr = (int)div64_u64(to_reclaim, bytes);
4709         if (!nr)
4710                 nr = 1;
4711         return nr;
4712 }
4713
4714 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4715
4716 /*
4717  * shrink metadata reservation for delalloc
4718  */
4719 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4720                             bool wait_ordered)
4721 {
4722         struct btrfs_fs_info *fs_info = root->fs_info;
4723         struct btrfs_block_rsv *block_rsv;
4724         struct btrfs_space_info *space_info;
4725         struct btrfs_trans_handle *trans;
4726         u64 delalloc_bytes;
4727         u64 max_reclaim;
4728         long time_left;
4729         unsigned long nr_pages;
4730         int loops;
4731         int items;
4732         enum btrfs_reserve_flush_enum flush;
4733
4734         /* Calc the number of the pages we need flush for space reservation */
4735         items = calc_reclaim_items_nr(fs_info, to_reclaim);
4736         to_reclaim = (u64)items * EXTENT_SIZE_PER_ITEM;
4737
4738         trans = (struct btrfs_trans_handle *)current->journal_info;
4739         block_rsv = &fs_info->delalloc_block_rsv;
4740         space_info = block_rsv->space_info;
4741
4742         delalloc_bytes = percpu_counter_sum_positive(
4743                                                 &fs_info->delalloc_bytes);
4744         if (delalloc_bytes == 0) {
4745                 if (trans)
4746                         return;
4747                 if (wait_ordered)
4748                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4749                 return;
4750         }
4751
4752         loops = 0;
4753         while (delalloc_bytes && loops < 3) {
4754                 max_reclaim = min(delalloc_bytes, to_reclaim);
4755                 nr_pages = max_reclaim >> PAGE_SHIFT;
4756                 btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items);
4757                 /*
4758                  * We need to wait for the async pages to actually start before
4759                  * we do anything.
4760                  */
4761                 max_reclaim = atomic_read(&fs_info->async_delalloc_pages);
4762                 if (!max_reclaim)
4763                         goto skip_async;
4764
4765                 if (max_reclaim <= nr_pages)
4766                         max_reclaim = 0;
4767                 else
4768                         max_reclaim -= nr_pages;
4769
4770                 wait_event(fs_info->async_submit_wait,
4771                            atomic_read(&fs_info->async_delalloc_pages) <=
4772                            (int)max_reclaim);
4773 skip_async:
4774                 if (!trans)
4775                         flush = BTRFS_RESERVE_FLUSH_ALL;
4776                 else
4777                         flush = BTRFS_RESERVE_NO_FLUSH;
4778                 spin_lock(&space_info->lock);
4779                 if (can_overcommit(root, space_info, orig, flush)) {
4780                         spin_unlock(&space_info->lock);
4781                         break;
4782                 }
4783                 if (list_empty(&space_info->tickets) &&
4784                     list_empty(&space_info->priority_tickets)) {
4785                         spin_unlock(&space_info->lock);
4786                         break;
4787                 }
4788                 spin_unlock(&space_info->lock);
4789
4790                 loops++;
4791                 if (wait_ordered && !trans) {
4792                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4793                 } else {
4794                         time_left = schedule_timeout_killable(1);
4795                         if (time_left)
4796                                 break;
4797                 }
4798                 delalloc_bytes = percpu_counter_sum_positive(
4799                                                 &fs_info->delalloc_bytes);
4800         }
4801 }
4802
4803 /**
4804  * maybe_commit_transaction - possibly commit the transaction if its ok to
4805  * @root - the root we're allocating for
4806  * @bytes - the number of bytes we want to reserve
4807  * @force - force the commit
4808  *
4809  * This will check to make sure that committing the transaction will actually
4810  * get us somewhere and then commit the transaction if it does.  Otherwise it
4811  * will return -ENOSPC.
4812  */
4813 static int may_commit_transaction(struct btrfs_fs_info *fs_info,
4814                                   struct btrfs_space_info *space_info,
4815                                   u64 bytes, int force)
4816 {
4817         struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
4818         struct btrfs_trans_handle *trans;
4819
4820         trans = (struct btrfs_trans_handle *)current->journal_info;
4821         if (trans)
4822                 return -EAGAIN;
4823
4824         if (force)
4825                 goto commit;
4826
4827         /* See if there is enough pinned space to make this reservation */
4828         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4829                                    bytes) >= 0)
4830                 goto commit;
4831
4832         /*
4833          * See if there is some space in the delayed insertion reservation for
4834          * this reservation.
4835          */
4836         if (space_info != delayed_rsv->space_info)
4837                 return -ENOSPC;
4838
4839         spin_lock(&delayed_rsv->lock);
4840         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4841                                    bytes - delayed_rsv->size) >= 0) {
4842                 spin_unlock(&delayed_rsv->lock);
4843                 return -ENOSPC;
4844         }
4845         spin_unlock(&delayed_rsv->lock);
4846
4847 commit:
4848         trans = btrfs_join_transaction(fs_info->extent_root);
4849         if (IS_ERR(trans))
4850                 return -ENOSPC;
4851
4852         return btrfs_commit_transaction(trans);
4853 }
4854
4855 struct reserve_ticket {
4856         u64 bytes;
4857         int error;
4858         struct list_head list;
4859         wait_queue_head_t wait;
4860 };
4861
4862 static int flush_space(struct btrfs_fs_info *fs_info,
4863                        struct btrfs_space_info *space_info, u64 num_bytes,
4864                        u64 orig_bytes, int state)
4865 {
4866         struct btrfs_root *root = fs_info->extent_root;
4867         struct btrfs_trans_handle *trans;
4868         int nr;
4869         int ret = 0;
4870
4871         switch (state) {
4872         case FLUSH_DELAYED_ITEMS_NR:
4873         case FLUSH_DELAYED_ITEMS:
4874                 if (state == FLUSH_DELAYED_ITEMS_NR)
4875                         nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
4876                 else
4877                         nr = -1;
4878
4879                 trans = btrfs_join_transaction(root);
4880                 if (IS_ERR(trans)) {
4881                         ret = PTR_ERR(trans);
4882                         break;
4883                 }
4884                 ret = btrfs_run_delayed_items_nr(trans, fs_info, nr);
4885                 btrfs_end_transaction(trans);
4886                 break;
4887         case FLUSH_DELALLOC:
4888         case FLUSH_DELALLOC_WAIT:
4889                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4890                                 state == FLUSH_DELALLOC_WAIT);
4891                 break;
4892         case ALLOC_CHUNK:
4893                 trans = btrfs_join_transaction(root);
4894                 if (IS_ERR(trans)) {
4895                         ret = PTR_ERR(trans);
4896                         break;
4897                 }
4898                 ret = do_chunk_alloc(trans, fs_info,
4899                                      btrfs_get_alloc_profile(root, 0),
4900                                      CHUNK_ALLOC_NO_FORCE);
4901                 btrfs_end_transaction(trans);
4902                 if (ret > 0 || ret == -ENOSPC)
4903                         ret = 0;
4904                 break;
4905         case COMMIT_TRANS:
4906                 ret = may_commit_transaction(fs_info, space_info,
4907                                              orig_bytes, 0);
4908                 break;
4909         default:
4910                 ret = -ENOSPC;
4911                 break;
4912         }
4913
4914         trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes,
4915                                 orig_bytes, state, ret);
4916         return ret;
4917 }
4918
4919 static inline u64
4920 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4921                                  struct btrfs_space_info *space_info)
4922 {
4923         struct reserve_ticket *ticket;
4924         u64 used;
4925         u64 expected;
4926         u64 to_reclaim = 0;
4927
4928         list_for_each_entry(ticket, &space_info->tickets, list)
4929                 to_reclaim += ticket->bytes;
4930         list_for_each_entry(ticket, &space_info->priority_tickets, list)
4931                 to_reclaim += ticket->bytes;
4932         if (to_reclaim)
4933                 return to_reclaim;
4934
4935         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
4936         if (can_overcommit(root, space_info, to_reclaim,
4937                            BTRFS_RESERVE_FLUSH_ALL))
4938                 return 0;
4939
4940         used = space_info->bytes_used + space_info->bytes_reserved +
4941                space_info->bytes_pinned + space_info->bytes_readonly +
4942                space_info->bytes_may_use;
4943         if (can_overcommit(root, space_info, SZ_1M, BTRFS_RESERVE_FLUSH_ALL))
4944                 expected = div_factor_fine(space_info->total_bytes, 95);
4945         else
4946                 expected = div_factor_fine(space_info->total_bytes, 90);
4947
4948         if (used > expected)
4949                 to_reclaim = used - expected;
4950         else
4951                 to_reclaim = 0;
4952         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4953                                      space_info->bytes_reserved);
4954         return to_reclaim;
4955 }
4956
4957 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4958                                         struct btrfs_root *root, u64 used)
4959 {
4960         struct btrfs_fs_info *fs_info = root->fs_info;
4961         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4962
4963         /* If we're just plain full then async reclaim just slows us down. */
4964         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
4965                 return 0;
4966
4967         if (!btrfs_calc_reclaim_metadata_size(root, space_info))
4968                 return 0;
4969
4970         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4971                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4972 }
4973
4974 static void wake_all_tickets(struct list_head *head)
4975 {
4976         struct reserve_ticket *ticket;
4977
4978         while (!list_empty(head)) {
4979                 ticket = list_first_entry(head, struct reserve_ticket, list);
4980                 list_del_init(&ticket->list);
4981                 ticket->error = -ENOSPC;
4982                 wake_up(&ticket->wait);
4983         }
4984 }
4985
4986 /*
4987  * This is for normal flushers, we can wait all goddamned day if we want to.  We
4988  * will loop and continuously try to flush as long as we are making progress.
4989  * We count progress as clearing off tickets each time we have to loop.
4990  */
4991 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4992 {
4993         struct btrfs_fs_info *fs_info;
4994         struct btrfs_space_info *space_info;
4995         u64 to_reclaim;
4996         int flush_state;
4997         int commit_cycles = 0;
4998         u64 last_tickets_id;
4999
5000         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
5001         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5002
5003         spin_lock(&space_info->lock);
5004         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5005                                                       space_info);
5006         if (!to_reclaim) {
5007                 space_info->flush = 0;
5008                 spin_unlock(&space_info->lock);
5009                 return;
5010         }
5011         last_tickets_id = space_info->tickets_id;
5012         spin_unlock(&space_info->lock);
5013
5014         flush_state = FLUSH_DELAYED_ITEMS_NR;
5015         do {
5016                 struct reserve_ticket *ticket;
5017                 int ret;
5018
5019                 ret = flush_space(fs_info, space_info, to_reclaim, to_reclaim,
5020                                   flush_state);
5021                 spin_lock(&space_info->lock);
5022                 if (list_empty(&space_info->tickets)) {
5023                         space_info->flush = 0;
5024                         spin_unlock(&space_info->lock);
5025                         return;
5026                 }
5027                 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
5028                                                               space_info);
5029                 ticket = list_first_entry(&space_info->tickets,
5030                                           struct reserve_ticket, list);
5031                 if (last_tickets_id == space_info->tickets_id) {
5032                         flush_state++;
5033                 } else {
5034                         last_tickets_id = space_info->tickets_id;
5035                         flush_state = FLUSH_DELAYED_ITEMS_NR;
5036                         if (commit_cycles)
5037                                 commit_cycles--;
5038                 }
5039
5040                 if (flush_state > COMMIT_TRANS) {
5041                         commit_cycles++;
5042                         if (commit_cycles > 2) {
5043                                 wake_all_tickets(&space_info->tickets);
5044                                 space_info->flush = 0;
5045                         } else {
5046                                 flush_state = FLUSH_DELAYED_ITEMS_NR;
5047                         }
5048                 }
5049                 spin_unlock(&space_info->lock);
5050         } while (flush_state <= COMMIT_TRANS);
5051 }
5052
5053 void btrfs_init_async_reclaim_work(struct work_struct *work)
5054 {
5055         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5056 }
5057
5058 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5059                                             struct btrfs_space_info *space_info,
5060                                             struct reserve_ticket *ticket)
5061 {
5062         u64 to_reclaim;
5063         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5064
5065         spin_lock(&space_info->lock);
5066         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->extent_root,
5067                                                       space_info);
5068         if (!to_reclaim) {
5069                 spin_unlock(&space_info->lock);
5070                 return;
5071         }
5072         spin_unlock(&space_info->lock);
5073
5074         do {
5075                 flush_space(fs_info, space_info, to_reclaim, to_reclaim,
5076                             flush_state);
5077                 flush_state++;
5078                 spin_lock(&space_info->lock);
5079                 if (ticket->bytes == 0) {
5080                         spin_unlock(&space_info->lock);
5081                         return;
5082                 }
5083                 spin_unlock(&space_info->lock);
5084
5085                 /*
5086                  * Priority flushers can't wait on delalloc without
5087                  * deadlocking.
5088                  */
5089                 if (flush_state == FLUSH_DELALLOC ||
5090                     flush_state == FLUSH_DELALLOC_WAIT)
5091                         flush_state = ALLOC_CHUNK;
5092         } while (flush_state < COMMIT_TRANS);
5093 }
5094
5095 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5096                                struct btrfs_space_info *space_info,
5097                                struct reserve_ticket *ticket, u64 orig_bytes)
5098
5099 {
5100         DEFINE_WAIT(wait);
5101         int ret = 0;
5102
5103         spin_lock(&space_info->lock);
5104         while (ticket->bytes > 0 && ticket->error == 0) {
5105                 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5106                 if (ret) {
5107                         ret = -EINTR;
5108                         break;
5109                 }
5110                 spin_unlock(&space_info->lock);
5111
5112                 schedule();
5113
5114                 finish_wait(&ticket->wait, &wait);
5115                 spin_lock(&space_info->lock);
5116         }
5117         if (!ret)
5118                 ret = ticket->error;
5119         if (!list_empty(&ticket->list))
5120                 list_del_init(&ticket->list);
5121         if (ticket->bytes && ticket->bytes < orig_bytes) {
5122                 u64 num_bytes = orig_bytes - ticket->bytes;
5123                 space_info->bytes_may_use -= num_bytes;
5124                 trace_btrfs_space_reservation(fs_info, "space_info",
5125                                               space_info->flags, num_bytes, 0);
5126         }
5127         spin_unlock(&space_info->lock);
5128
5129         return ret;
5130 }
5131
5132 /**
5133  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5134  * @root - the root we're allocating for
5135  * @space_info - the space info we want to allocate from
5136  * @orig_bytes - the number of bytes we want
5137  * @flush - whether or not we can flush to make our reservation
5138  *
5139  * This will reserve orig_bytes number of bytes from the space info associated
5140  * with the block_rsv.  If there is not enough space it will make an attempt to
5141  * flush out space to make room.  It will do this by flushing delalloc if
5142  * possible or committing the transaction.  If flush is 0 then no attempts to
5143  * regain reservations will be made and this will fail if there is not enough
5144  * space already.
5145  */
5146 static int __reserve_metadata_bytes(struct btrfs_root *root,
5147                                     struct btrfs_space_info *space_info,
5148                                     u64 orig_bytes,
5149                                     enum btrfs_reserve_flush_enum flush)
5150 {
5151         struct btrfs_fs_info *fs_info = root->fs_info;
5152         struct reserve_ticket ticket;
5153         u64 used;
5154         int ret = 0;
5155
5156         ASSERT(orig_bytes);
5157         ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5158
5159         spin_lock(&space_info->lock);
5160         ret = -ENOSPC;
5161         used = btrfs_space_info_used(space_info, true);
5162
5163         /*
5164          * If we have enough space then hooray, make our reservation and carry
5165          * on.  If not see if we can overcommit, and if we can, hooray carry on.
5166          * If not things get more complicated.
5167          */
5168         if (used + orig_bytes <= space_info->total_bytes) {
5169                 space_info->bytes_may_use += orig_bytes;
5170                 trace_btrfs_space_reservation(fs_info, "space_info",
5171                                               space_info->flags, orig_bytes, 1);
5172                 ret = 0;
5173         } else if (can_overcommit(root, space_info, orig_bytes, flush)) {
5174                 space_info->bytes_may_use += orig_bytes;
5175                 trace_btrfs_space_reservation(fs_info, "space_info",
5176                                               space_info->flags, orig_bytes, 1);
5177                 ret = 0;
5178         }
5179
5180         /*
5181          * If we couldn't make a reservation then setup our reservation ticket
5182          * and kick the async worker if it's not already running.
5183          *
5184          * If we are a priority flusher then we just need to add our ticket to
5185          * the list and we will do our own flushing further down.
5186          */
5187         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5188                 ticket.bytes = orig_bytes;
5189                 ticket.error = 0;
5190                 init_waitqueue_head(&ticket.wait);
5191                 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5192                         list_add_tail(&ticket.list, &space_info->tickets);
5193                         if (!space_info->flush) {
5194                                 space_info->flush = 1;
5195                                 trace_btrfs_trigger_flush(fs_info,
5196                                                           space_info->flags,
5197                                                           orig_bytes, flush,
5198                                                           "enospc");
5199                                 queue_work(system_unbound_wq,
5200                                            &root->fs_info->async_reclaim_work);
5201                         }
5202                 } else {
5203                         list_add_tail(&ticket.list,
5204                                       &space_info->priority_tickets);
5205                 }
5206         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5207                 used += orig_bytes;
5208                 /*
5209                  * We will do the space reservation dance during log replay,
5210                  * which means we won't have fs_info->fs_root set, so don't do
5211                  * the async reclaim as we will panic.
5212                  */
5213                 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
5214                     need_do_async_reclaim(space_info, root, used) &&
5215                     !work_busy(&fs_info->async_reclaim_work)) {
5216                         trace_btrfs_trigger_flush(fs_info, space_info->flags,
5217                                                   orig_bytes, flush, "preempt");
5218                         queue_work(system_unbound_wq,
5219                                    &fs_info->async_reclaim_work);
5220                 }
5221         }
5222         spin_unlock(&space_info->lock);
5223         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5224                 return ret;
5225
5226         if (flush == BTRFS_RESERVE_FLUSH_ALL)
5227                 return wait_reserve_ticket(fs_info, space_info, &ticket,
5228                                            orig_bytes);
5229
5230         ret = 0;
5231         priority_reclaim_metadata_space(fs_info, space_info, &ticket);
5232         spin_lock(&space_info->lock);
5233         if (ticket.bytes) {
5234                 if (ticket.bytes < orig_bytes) {
5235                         u64 num_bytes = orig_bytes - ticket.bytes;
5236                         space_info->bytes_may_use -= num_bytes;
5237                         trace_btrfs_space_reservation(fs_info, "space_info",
5238                                                       space_info->flags,
5239                                                       num_bytes, 0);
5240
5241                 }
5242                 list_del_init(&ticket.list);
5243                 ret = -ENOSPC;
5244         }
5245         spin_unlock(&space_info->lock);
5246         ASSERT(list_empty(&ticket.list));
5247         return ret;
5248 }
5249
5250 /**
5251  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5252  * @root - the root we're allocating for
5253  * @block_rsv - the block_rsv we're allocating for
5254  * @orig_bytes - the number of bytes we want
5255  * @flush - whether or not we can flush to make our reservation
5256  *
5257  * This will reserve orgi_bytes number of bytes from the space info associated
5258  * with the block_rsv.  If there is not enough space it will make an attempt to
5259  * flush out space to make room.  It will do this by flushing delalloc if
5260  * possible or committing the transaction.  If flush is 0 then no attempts to
5261  * regain reservations will be made and this will fail if there is not enough
5262  * space already.
5263  */
5264 static int reserve_metadata_bytes(struct btrfs_root *root,
5265                                   struct btrfs_block_rsv *block_rsv,
5266                                   u64 orig_bytes,
5267                                   enum btrfs_reserve_flush_enum flush)
5268 {
5269         struct btrfs_fs_info *fs_info = root->fs_info;
5270         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5271         int ret;
5272
5273         ret = __reserve_metadata_bytes(root, block_rsv->space_info, orig_bytes,
5274                                        flush);
5275         if (ret == -ENOSPC &&
5276             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5277                 if (block_rsv != global_rsv &&
5278                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5279                         ret = 0;
5280         }
5281         if (ret == -ENOSPC)
5282                 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
5283                                               block_rsv->space_info->flags,
5284                                               orig_bytes, 1);
5285         return ret;
5286 }
5287
5288 static struct btrfs_block_rsv *get_block_rsv(
5289                                         const struct btrfs_trans_handle *trans,
5290                                         const struct btrfs_root *root)
5291 {
5292         struct btrfs_fs_info *fs_info = root->fs_info;
5293         struct btrfs_block_rsv *block_rsv = NULL;
5294
5295         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5296             (root == fs_info->csum_root && trans->adding_csums) ||
5297             (root == fs_info->uuid_root))
5298                 block_rsv = trans->block_rsv;
5299
5300         if (!block_rsv)
5301                 block_rsv = root->block_rsv;
5302
5303         if (!block_rsv)
5304                 block_rsv = &fs_info->empty_block_rsv;
5305
5306         return block_rsv;
5307 }
5308
5309 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5310                                u64 num_bytes)
5311 {
5312         int ret = -ENOSPC;
5313         spin_lock(&block_rsv->lock);
5314         if (block_rsv->reserved >= num_bytes) {
5315                 block_rsv->reserved -= num_bytes;
5316                 if (block_rsv->reserved < block_rsv->size)
5317                         block_rsv->full = 0;
5318                 ret = 0;
5319         }
5320         spin_unlock(&block_rsv->lock);
5321         return ret;
5322 }
5323
5324 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5325                                 u64 num_bytes, int update_size)
5326 {
5327         spin_lock(&block_rsv->lock);
5328         block_rsv->reserved += num_bytes;
5329         if (update_size)
5330                 block_rsv->size += num_bytes;
5331         else if (block_rsv->reserved >= block_rsv->size)
5332                 block_rsv->full = 1;
5333         spin_unlock(&block_rsv->lock);
5334 }
5335
5336 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5337                              struct btrfs_block_rsv *dest, u64 num_bytes,
5338                              int min_factor)
5339 {
5340         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5341         u64 min_bytes;
5342
5343         if (global_rsv->space_info != dest->space_info)
5344                 return -ENOSPC;
5345
5346         spin_lock(&global_rsv->lock);
5347         min_bytes = div_factor(global_rsv->size, min_factor);
5348         if (global_rsv->reserved < min_bytes + num_bytes) {
5349                 spin_unlock(&global_rsv->lock);
5350                 return -ENOSPC;
5351         }
5352         global_rsv->reserved -= num_bytes;
5353         if (global_rsv->reserved < global_rsv->size)
5354                 global_rsv->full = 0;
5355         spin_unlock(&global_rsv->lock);
5356
5357         block_rsv_add_bytes(dest, num_bytes, 1);
5358         return 0;
5359 }
5360
5361 /*
5362  * This is for space we already have accounted in space_info->bytes_may_use, so
5363  * basically when we're returning space from block_rsv's.
5364  */
5365 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5366                                      struct btrfs_space_info *space_info,
5367                                      u64 num_bytes)
5368 {
5369         struct reserve_ticket *ticket;
5370         struct list_head *head;
5371         u64 used;
5372         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5373         bool check_overcommit = false;
5374
5375         spin_lock(&space_info->lock);
5376         head = &space_info->priority_tickets;
5377
5378         /*
5379          * If we are over our limit then we need to check and see if we can
5380          * overcommit, and if we can't then we just need to free up our space
5381          * and not satisfy any requests.
5382          */
5383         used = space_info->bytes_used + space_info->bytes_reserved +
5384                 space_info->bytes_pinned + space_info->bytes_readonly +
5385                 space_info->bytes_may_use;
5386         if (used - num_bytes >= space_info->total_bytes)
5387                 check_overcommit = true;
5388 again:
5389         while (!list_empty(head) && num_bytes) {
5390                 ticket = list_first_entry(head, struct reserve_ticket,
5391                                           list);
5392                 /*
5393                  * We use 0 bytes because this space is already reserved, so
5394                  * adding the ticket space would be a double count.
5395                  */
5396                 if (check_overcommit &&
5397                     !can_overcommit(fs_info->extent_root, space_info, 0,
5398                                     flush))
5399                         break;
5400                 if (num_bytes >= ticket->bytes) {
5401                         list_del_init(&ticket->list);
5402                         num_bytes -= ticket->bytes;
5403                         ticket->bytes = 0;
5404                         space_info->tickets_id++;
5405                         wake_up(&ticket->wait);
5406                 } else {
5407                         ticket->bytes -= num_bytes;
5408                         num_bytes = 0;
5409                 }
5410         }
5411
5412         if (num_bytes && head == &space_info->priority_tickets) {
5413                 head = &space_info->tickets;
5414                 flush = BTRFS_RESERVE_FLUSH_ALL;
5415                 goto again;
5416         }
5417         space_info->bytes_may_use -= num_bytes;
5418         trace_btrfs_space_reservation(fs_info, "space_info",
5419                                       space_info->flags, num_bytes, 0);
5420         spin_unlock(&space_info->lock);
5421 }
5422
5423 /*
5424  * This is for newly allocated space that isn't accounted in
5425  * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
5426  * we use this helper.
5427  */
5428 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5429                                      struct btrfs_space_info *space_info,
5430                                      u64 num_bytes)
5431 {
5432         struct reserve_ticket *ticket;
5433         struct list_head *head = &space_info->priority_tickets;
5434
5435 again:
5436         while (!list_empty(head) && num_bytes) {
5437                 ticket = list_first_entry(head, struct reserve_ticket,
5438                                           list);
5439                 if (num_bytes >= ticket->bytes) {
5440                         trace_btrfs_space_reservation(fs_info, "space_info",
5441                                                       space_info->flags,
5442                                                       ticket->bytes, 1);
5443                         list_del_init(&ticket->list);
5444                         num_bytes -= ticket->bytes;
5445                         space_info->bytes_may_use += ticket->bytes;
5446                         ticket->bytes = 0;
5447                         space_info->tickets_id++;
5448                         wake_up(&ticket->wait);
5449                 } else {
5450                         trace_btrfs_space_reservation(fs_info, "space_info",
5451                                                       space_info->flags,
5452                                                       num_bytes, 1);
5453                         space_info->bytes_may_use += num_bytes;
5454                         ticket->bytes -= num_bytes;
5455                         num_bytes = 0;
5456                 }
5457         }
5458
5459         if (num_bytes && head == &space_info->priority_tickets) {
5460                 head = &space_info->tickets;
5461                 goto again;
5462         }
5463 }
5464
5465 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5466                                     struct btrfs_block_rsv *block_rsv,
5467                                     struct btrfs_block_rsv *dest, u64 num_bytes)
5468 {
5469         struct btrfs_space_info *space_info = block_rsv->space_info;
5470
5471         spin_lock(&block_rsv->lock);
5472         if (num_bytes == (u64)-1)
5473                 num_bytes = block_rsv->size;
5474         block_rsv->size -= num_bytes;
5475         if (block_rsv->reserved >= block_rsv->size) {
5476                 num_bytes = block_rsv->reserved - block_rsv->size;
5477                 block_rsv->reserved = block_rsv->size;
5478                 block_rsv->full = 1;
5479         } else {
5480                 num_bytes = 0;
5481         }
5482         spin_unlock(&block_rsv->lock);
5483
5484         if (num_bytes > 0) {
5485                 if (dest) {
5486                         spin_lock(&dest->lock);
5487                         if (!dest->full) {
5488                                 u64 bytes_to_add;
5489
5490                                 bytes_to_add = dest->size - dest->reserved;
5491                                 bytes_to_add = min(num_bytes, bytes_to_add);
5492                                 dest->reserved += bytes_to_add;
5493                                 if (dest->reserved >= dest->size)
5494                                         dest->full = 1;
5495                                 num_bytes -= bytes_to_add;
5496                         }
5497                         spin_unlock(&dest->lock);
5498                 }
5499                 if (num_bytes)
5500                         space_info_add_old_bytes(fs_info, space_info,
5501                                                  num_bytes);
5502         }
5503 }
5504
5505 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5506                             struct btrfs_block_rsv *dst, u64 num_bytes,
5507                             int update_size)
5508 {
5509         int ret;
5510
5511         ret = block_rsv_use_bytes(src, num_bytes);
5512         if (ret)
5513                 return ret;
5514
5515         block_rsv_add_bytes(dst, num_bytes, update_size);
5516         return 0;
5517 }
5518
5519 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5520 {
5521         memset(rsv, 0, sizeof(*rsv));
5522         spin_lock_init(&rsv->lock);
5523         rsv->type = type;
5524 }
5525
5526 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
5527                                               unsigned short type)
5528 {
5529         struct btrfs_block_rsv *block_rsv;
5530
5531         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5532         if (!block_rsv)
5533                 return NULL;
5534
5535         btrfs_init_block_rsv(block_rsv, type);
5536         block_rsv->space_info = __find_space_info(fs_info,
5537                                                   BTRFS_BLOCK_GROUP_METADATA);
5538         return block_rsv;
5539 }
5540
5541 void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
5542                           struct btrfs_block_rsv *rsv)
5543 {
5544         if (!rsv)
5545                 return;
5546         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5547         kfree(rsv);
5548 }
5549
5550 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5551 {
5552         kfree(rsv);
5553 }
5554
5555 int btrfs_block_rsv_add(struct btrfs_root *root,
5556                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5557                         enum btrfs_reserve_flush_enum flush)
5558 {
5559         int ret;
5560
5561         if (num_bytes == 0)
5562                 return 0;
5563
5564         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5565         if (!ret) {
5566                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5567                 return 0;
5568         }
5569
5570         return ret;
5571 }
5572
5573 int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
5574 {
5575         u64 num_bytes = 0;
5576         int ret = -ENOSPC;
5577
5578         if (!block_rsv)
5579                 return 0;
5580
5581         spin_lock(&block_rsv->lock);
5582         num_bytes = div_factor(block_rsv->size, min_factor);
5583         if (block_rsv->reserved >= num_bytes)
5584                 ret = 0;
5585         spin_unlock(&block_rsv->lock);
5586
5587         return ret;
5588 }
5589
5590 int btrfs_block_rsv_refill(struct btrfs_root *root,
5591                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5592                            enum btrfs_reserve_flush_enum flush)
5593 {
5594         u64 num_bytes = 0;
5595         int ret = -ENOSPC;
5596
5597         if (!block_rsv)
5598                 return 0;
5599
5600         spin_lock(&block_rsv->lock);
5601         num_bytes = min_reserved;
5602         if (block_rsv->reserved >= num_bytes)
5603                 ret = 0;
5604         else
5605                 num_bytes -= block_rsv->reserved;
5606         spin_unlock(&block_rsv->lock);
5607
5608         if (!ret)
5609                 return 0;
5610
5611         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5612         if (!ret) {
5613                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5614                 return 0;
5615         }
5616
5617         return ret;
5618 }
5619
5620 void btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
5621                              struct btrfs_block_rsv *block_rsv,
5622                              u64 num_bytes)
5623 {
5624         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5625
5626         if (global_rsv == block_rsv ||
5627             block_rsv->space_info != global_rsv->space_info)
5628                 global_rsv = NULL;
5629         block_rsv_release_bytes(fs_info, block_rsv, global_rsv, num_bytes);
5630 }
5631
5632 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5633 {
5634         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5635         struct btrfs_space_info *sinfo = block_rsv->space_info;
5636         u64 num_bytes;
5637
5638         /*
5639          * The global block rsv is based on the size of the extent tree, the
5640          * checksum tree and the root tree.  If the fs is empty we want to set
5641          * it to a minimal amount for safety.
5642          */
5643         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5644                 btrfs_root_used(&fs_info->csum_root->root_item) +
5645                 btrfs_root_used(&fs_info->tree_root->root_item);
5646         num_bytes = max_t(u64, num_bytes, SZ_16M);
5647
5648         spin_lock(&sinfo->lock);
5649         spin_lock(&block_rsv->lock);
5650
5651         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5652
5653         if (block_rsv->reserved < block_rsv->size) {
5654                 num_bytes = btrfs_space_info_used(sinfo, true);
5655                 if (sinfo->total_bytes > num_bytes) {
5656                         num_bytes = sinfo->total_bytes - num_bytes;
5657                         num_bytes = min(num_bytes,
5658                                         block_rsv->size - block_rsv->reserved);
5659                         block_rsv->reserved += num_bytes;
5660                         sinfo->bytes_may_use += num_bytes;
5661                         trace_btrfs_space_reservation(fs_info, "space_info",
5662                                                       sinfo->flags, num_bytes,
5663                                                       1);
5664                 }
5665         } else if (block_rsv->reserved > block_rsv->size) {
5666                 num_bytes = block_rsv->reserved - block_rsv->size;
5667                 sinfo->bytes_may_use -= num_bytes;
5668                 trace_btrfs_space_reservation(fs_info, "space_info",
5669                                       sinfo->flags, num_bytes, 0);
5670                 block_rsv->reserved = block_rsv->size;
5671         }
5672
5673         if (block_rsv->reserved == block_rsv->size)
5674                 block_rsv->full = 1;
5675         else
5676                 block_rsv->full = 0;
5677
5678         spin_unlock(&block_rsv->lock);
5679         spin_unlock(&sinfo->lock);
5680 }
5681
5682 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5683 {
5684         struct btrfs_space_info *space_info;
5685
5686         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5687         fs_info->chunk_block_rsv.space_info = space_info;
5688
5689         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5690         fs_info->global_block_rsv.space_info = space_info;
5691         fs_info->delalloc_block_rsv.space_info = space_info;
5692         fs_info->trans_block_rsv.space_info = space_info;
5693         fs_info->empty_block_rsv.space_info = space_info;
5694         fs_info->delayed_block_rsv.space_info = space_info;
5695
5696         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5697         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5698         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5699         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5700         if (fs_info->quota_root)
5701                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5702         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5703
5704         update_global_block_rsv(fs_info);
5705 }
5706
5707 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5708 {
5709         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5710                                 (u64)-1);
5711         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5712         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5713         WARN_ON(fs_info->trans_block_rsv.size > 0);
5714         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5715         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5716         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5717         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5718         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5719 }
5720
5721 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5722                                   struct btrfs_fs_info *fs_info)
5723 {
5724         if (!trans->block_rsv)
5725                 return;
5726
5727         if (!trans->bytes_reserved)
5728                 return;
5729
5730         trace_btrfs_space_reservation(fs_info, "transaction",
5731                                       trans->transid, trans->bytes_reserved, 0);
5732         btrfs_block_rsv_release(fs_info, trans->block_rsv,
5733                                 trans->bytes_reserved);
5734         trans->bytes_reserved = 0;
5735 }
5736
5737 /*
5738  * To be called after all the new block groups attached to the transaction
5739  * handle have been created (btrfs_create_pending_block_groups()).
5740  */
5741 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5742 {
5743         struct btrfs_fs_info *fs_info = trans->fs_info;
5744
5745         if (!trans->chunk_bytes_reserved)
5746                 return;
5747
5748         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5749
5750         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5751                                 trans->chunk_bytes_reserved);
5752         trans->chunk_bytes_reserved = 0;
5753 }
5754
5755 /* Can only return 0 or -ENOSPC */
5756 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5757                                   struct btrfs_inode *inode)
5758 {
5759         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
5760         struct btrfs_root *root = inode->root;
5761         /*
5762          * We always use trans->block_rsv here as we will have reserved space
5763          * for our orphan when starting the transaction, using get_block_rsv()
5764          * here will sometimes make us choose the wrong block rsv as we could be
5765          * doing a reloc inode for a non refcounted root.
5766          */
5767         struct btrfs_block_rsv *src_rsv = trans->block_rsv;
5768         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5769
5770         /*
5771          * We need to hold space in order to delete our orphan item once we've
5772          * added it, so this takes the reservation so we can release it later
5773          * when we are truly done with the orphan item.
5774          */
5775         u64 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
5776
5777         trace_btrfs_space_reservation(fs_info, "orphan", btrfs_ino(inode),
5778                         num_bytes, 1);
5779         return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
5780 }
5781
5782 void btrfs_orphan_release_metadata(struct btrfs_inode *inode)
5783 {
5784         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
5785         struct btrfs_root *root = inode->root;
5786         u64 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
5787
5788         trace_btrfs_space_reservation(fs_info, "orphan", btrfs_ino(inode),
5789                         num_bytes, 0);
5790         btrfs_block_rsv_release(fs_info, root->orphan_block_rsv, num_bytes);
5791 }
5792
5793 /*
5794  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5795  * root: the root of the parent directory
5796  * rsv: block reservation
5797  * items: the number of items that we need do reservation
5798  * qgroup_reserved: used to return the reserved size in qgroup
5799  *
5800  * This function is used to reserve the space for snapshot/subvolume
5801  * creation and deletion. Those operations are different with the
5802  * common file/directory operations, they change two fs/file trees
5803  * and root tree, the number of items that the qgroup reserves is
5804  * different with the free space reservation. So we can not use
5805  * the space reservation mechanism in start_transaction().
5806  */
5807 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5808                                      struct btrfs_block_rsv *rsv,
5809                                      int items,
5810                                      u64 *qgroup_reserved,
5811                                      bool use_global_rsv)
5812 {
5813         u64 num_bytes;
5814         int ret;
5815         struct btrfs_fs_info *fs_info = root->fs_info;
5816         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5817
5818         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
5819                 /* One for parent inode, two for dir entries */
5820                 num_bytes = 3 * fs_info->nodesize;
5821                 ret = btrfs_qgroup_reserve_meta(root, num_bytes, true);
5822                 if (ret)
5823                         return ret;
5824         } else {
5825                 num_bytes = 0;
5826         }
5827
5828         *qgroup_reserved = num_bytes;
5829
5830         num_bytes = btrfs_calc_trans_metadata_size(fs_info, items);
5831         rsv->space_info = __find_space_info(fs_info,
5832                                             BTRFS_BLOCK_GROUP_METADATA);
5833         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5834                                   BTRFS_RESERVE_FLUSH_ALL);
5835
5836         if (ret == -ENOSPC && use_global_rsv)
5837                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5838
5839         if (ret && *qgroup_reserved)
5840                 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5841
5842         return ret;
5843 }
5844
5845 void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
5846                                       struct btrfs_block_rsv *rsv)
5847 {
5848         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5849 }
5850
5851 /**
5852  * drop_outstanding_extent - drop an outstanding extent
5853  * @inode: the inode we're dropping the extent for
5854  * @num_bytes: the number of bytes we're releasing.
5855  *
5856  * This is called when we are freeing up an outstanding extent, either called
5857  * after an error or after an extent is written.  This will return the number of
5858  * reserved extents that need to be freed.  This must be called with
5859  * BTRFS_I(inode)->lock held.
5860  */
5861 static unsigned drop_outstanding_extent(struct btrfs_inode *inode,
5862                 u64 num_bytes)
5863 {
5864         unsigned drop_inode_space = 0;
5865         unsigned dropped_extents = 0;
5866         unsigned num_extents;
5867
5868         num_extents = count_max_extents(num_bytes);
5869         ASSERT(num_extents);
5870         ASSERT(inode->outstanding_extents >= num_extents);
5871         inode->outstanding_extents -= num_extents;
5872
5873         if (inode->outstanding_extents == 0 &&
5874             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5875                                &inode->runtime_flags))
5876                 drop_inode_space = 1;
5877
5878         /*
5879          * If we have more or the same amount of outstanding extents than we have
5880          * reserved then we need to leave the reserved extents count alone.
5881          */
5882         if (inode->outstanding_extents >= inode->reserved_extents)
5883                 return drop_inode_space;
5884
5885         dropped_extents = inode->reserved_extents - inode->outstanding_extents;
5886         inode->reserved_extents -= dropped_extents;
5887         return dropped_extents + drop_inode_space;
5888 }
5889
5890 /**
5891  * calc_csum_metadata_size - return the amount of metadata space that must be
5892  *      reserved/freed for the given bytes.
5893  * @inode: the inode we're manipulating
5894  * @num_bytes: the number of bytes in question
5895  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5896  *
5897  * This adjusts the number of csum_bytes in the inode and then returns the
5898  * correct amount of metadata that must either be reserved or freed.  We
5899  * calculate how many checksums we can fit into one leaf and then divide the
5900  * number of bytes that will need to be checksumed by this value to figure out
5901  * how many checksums will be required.  If we are adding bytes then the number
5902  * may go up and we will return the number of additional bytes that must be
5903  * reserved.  If it is going down we will return the number of bytes that must
5904  * be freed.
5905  *
5906  * This must be called with BTRFS_I(inode)->lock held.
5907  */
5908 static u64 calc_csum_metadata_size(struct btrfs_inode *inode, u64 num_bytes,
5909                                    int reserve)
5910 {
5911         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
5912         u64 old_csums, num_csums;
5913
5914         if (inode->flags & BTRFS_INODE_NODATASUM && inode->csum_bytes == 0)
5915                 return 0;
5916
5917         old_csums = btrfs_csum_bytes_to_leaves(fs_info, inode->csum_bytes);
5918         if (reserve)
5919                 inode->csum_bytes += num_bytes;
5920         else
5921                 inode->csum_bytes -= num_bytes;
5922         num_csums = btrfs_csum_bytes_to_leaves(fs_info, inode->csum_bytes);
5923
5924         /* No change, no need to reserve more */
5925         if (old_csums == num_csums)
5926                 return 0;
5927
5928         if (reserve)
5929                 return btrfs_calc_trans_metadata_size(fs_info,
5930                                                       num_csums - old_csums);
5931
5932         return btrfs_calc_trans_metadata_size(fs_info, old_csums - num_csums);
5933 }
5934
5935 int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
5936 {
5937         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
5938         struct btrfs_root *root = inode->root;
5939         struct btrfs_block_rsv *block_rsv = &fs_info->delalloc_block_rsv;
5940         u64 to_reserve = 0;
5941         u64 csum_bytes;
5942         unsigned nr_extents;
5943         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5944         int ret = 0;
5945         bool delalloc_lock = true;
5946         u64 to_free = 0;
5947         unsigned dropped;
5948         bool release_extra = false;
5949
5950         /* If we are a free space inode we need to not flush since we will be in
5951          * the middle of a transaction commit.  We also don't need the delalloc
5952          * mutex since we won't race with anybody.  We need this mostly to make
5953          * lockdep shut its filthy mouth.
5954          *
5955          * If we have a transaction open (can happen if we call truncate_block
5956          * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
5957          */
5958         if (btrfs_is_free_space_inode(inode)) {
5959                 flush = BTRFS_RESERVE_NO_FLUSH;
5960                 delalloc_lock = false;
5961         } else if (current->journal_info) {
5962                 flush = BTRFS_RESERVE_FLUSH_LIMIT;
5963         }
5964
5965         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5966             btrfs_transaction_in_commit(fs_info))
5967                 schedule_timeout(1);
5968
5969         if (delalloc_lock)
5970                 mutex_lock(&inode->delalloc_mutex);
5971
5972         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
5973
5974         spin_lock(&inode->lock);
5975         nr_extents = count_max_extents(num_bytes);
5976         inode->outstanding_extents += nr_extents;
5977
5978         nr_extents = 0;
5979         if (inode->outstanding_extents > inode->reserved_extents)
5980                 nr_extents += inode->outstanding_extents -
5981                         inode->reserved_extents;
5982
5983         /* We always want to reserve a slot for updating the inode. */
5984         to_reserve = btrfs_calc_trans_metadata_size(fs_info, nr_extents + 1);
5985         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5986         csum_bytes = inode->csum_bytes;
5987         spin_unlock(&inode->lock);
5988
5989         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
5990                 ret = btrfs_qgroup_reserve_meta(root,
5991                                 nr_extents * fs_info->nodesize, true);
5992                 if (ret)
5993                         goto out_fail;
5994         }
5995
5996         ret = btrfs_block_rsv_add(root, block_rsv, to_reserve, flush);
5997         if (unlikely(ret)) {
5998                 btrfs_qgroup_free_meta(root,
5999                                        nr_extents * fs_info->nodesize);
6000                 goto out_fail;
6001         }
6002
6003         spin_lock(&inode->lock);
6004         if (test_and_set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
6005                              &inode->runtime_flags)) {
6006                 to_reserve -= btrfs_calc_trans_metadata_size(fs_info, 1);
6007                 release_extra = true;
6008         }
6009         inode->reserved_extents += nr_extents;
6010         spin_unlock(&inode->lock);
6011
6012         if (delalloc_lock)
6013                 mutex_unlock(&inode->delalloc_mutex);
6014
6015         if (to_reserve)
6016                 trace_btrfs_space_reservation(fs_info, "delalloc",
6017                                               btrfs_ino(inode), to_reserve, 1);
6018         if (release_extra)
6019                 btrfs_block_rsv_release(fs_info, block_rsv,
6020                                 btrfs_calc_trans_metadata_size(fs_info, 1));
6021         return 0;
6022
6023 out_fail:
6024         spin_lock(&inode->lock);
6025         dropped = drop_outstanding_extent(inode, num_bytes);
6026         /*
6027          * If the inodes csum_bytes is the same as the original
6028          * csum_bytes then we know we haven't raced with any free()ers
6029          * so we can just reduce our inodes csum bytes and carry on.
6030          */
6031         if (inode->csum_bytes == csum_bytes) {
6032                 calc_csum_metadata_size(inode, num_bytes, 0);
6033         } else {
6034                 u64 orig_csum_bytes = inode->csum_bytes;
6035                 u64 bytes;
6036
6037                 /*
6038                  * This is tricky, but first we need to figure out how much we
6039                  * freed from any free-ers that occurred during this
6040                  * reservation, so we reset ->csum_bytes to the csum_bytes
6041                  * before we dropped our lock, and then call the free for the
6042                  * number of bytes that were freed while we were trying our
6043                  * reservation.
6044                  */
6045                 bytes = csum_bytes - inode->csum_bytes;
6046                 inode->csum_bytes = csum_bytes;
6047                 to_free = calc_csum_metadata_size(inode, bytes, 0);
6048
6049
6050                 /*
6051                  * Now we need to see how much we would have freed had we not
6052                  * been making this reservation and our ->csum_bytes were not
6053                  * artificially inflated.
6054                  */
6055                 inode->csum_bytes = csum_bytes - num_bytes;
6056                 bytes = csum_bytes - orig_csum_bytes;
6057                 bytes = calc_csum_metadata_size(inode, bytes, 0);
6058
6059                 /*
6060                  * Now reset ->csum_bytes to what it should be.  If bytes is
6061                  * more than to_free then we would have freed more space had we
6062                  * not had an artificially high ->csum_bytes, so we need to free
6063                  * the remainder.  If bytes is the same or less then we don't
6064                  * need to do anything, the other free-ers did the correct
6065                  * thing.
6066                  */
6067                 inode->csum_bytes = orig_csum_bytes - num_bytes;
6068                 if (bytes > to_free)
6069                         to_free = bytes - to_free;
6070                 else
6071                         to_free = 0;
6072         }
6073         spin_unlock(&inode->lock);
6074         if (dropped)
6075                 to_free += btrfs_calc_trans_metadata_size(fs_info, dropped);
6076
6077         if (to_free) {
6078                 btrfs_block_rsv_release(fs_info, block_rsv, to_free);
6079                 trace_btrfs_space_reservation(fs_info, "delalloc",
6080                                               btrfs_ino(inode), to_free, 0);
6081         }
6082         if (delalloc_lock)
6083                 mutex_unlock(&inode->delalloc_mutex);
6084         return ret;
6085 }
6086
6087 /**
6088  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6089  * @inode: the inode to release the reservation for
6090  * @num_bytes: the number of bytes we're releasing
6091  *
6092  * This will release the metadata reservation for an inode.  This can be called
6093  * once we complete IO for a given set of bytes to release their metadata
6094  * reservations.
6095  */
6096 void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes)
6097 {
6098         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6099         u64 to_free = 0;
6100         unsigned dropped;
6101
6102         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
6103         spin_lock(&inode->lock);
6104         dropped = drop_outstanding_extent(inode, num_bytes);
6105
6106         if (num_bytes)
6107                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
6108         spin_unlock(&inode->lock);
6109         if (dropped > 0)
6110                 to_free += btrfs_calc_trans_metadata_size(fs_info, dropped);
6111
6112         if (btrfs_is_testing(fs_info))
6113                 return;
6114
6115         trace_btrfs_space_reservation(fs_info, "delalloc", btrfs_ino(inode),
6116                                       to_free, 0);
6117
6118         btrfs_block_rsv_release(fs_info, &fs_info->delalloc_block_rsv, to_free);
6119 }
6120
6121 /**
6122  * btrfs_delalloc_reserve_space - reserve data and metadata space for
6123  * delalloc
6124  * @inode: inode we're writing to
6125  * @start: start range we are writing to
6126  * @len: how long the range we are writing to
6127  *
6128  * This will do the following things
6129  *
6130  * o reserve space in data space info for num bytes
6131  *   and reserve precious corresponding qgroup space
6132  *   (Done in check_data_free_space)
6133  *
6134  * o reserve space for metadata space, based on the number of outstanding
6135  *   extents and how much csums will be needed
6136  *   also reserve metadata space in a per root over-reserve method.
6137  * o add to the inodes->delalloc_bytes
6138  * o add it to the fs_info's delalloc inodes list.
6139  *   (Above 3 all done in delalloc_reserve_metadata)
6140  *
6141  * Return 0 for success
6142  * Return <0 for error(-ENOSPC or -EQUOT)
6143  */
6144 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
6145 {
6146         int ret;
6147
6148         ret = btrfs_check_data_free_space(inode, start, len);
6149         if (ret < 0)
6150                 return ret;
6151         ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len);
6152         if (ret < 0)
6153                 btrfs_free_reserved_data_space(inode, start, len);
6154         return ret;
6155 }
6156
6157 /**
6158  * btrfs_delalloc_release_space - release data and metadata space for delalloc
6159  * @inode: inode we're releasing space for
6160  * @start: start position of the space already reserved
6161  * @len: the len of the space already reserved
6162  *
6163  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
6164  * called in the case that we don't need the metadata AND data reservations
6165  * anymore.  So if there is an error or we insert an inline extent.
6166  *
6167  * This function will release the metadata space that was not used and will
6168  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6169  * list if there are no delalloc bytes left.
6170  * Also it will handle the qgroup reserved space.
6171  */
6172 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
6173 {
6174         btrfs_delalloc_release_metadata(BTRFS_I(inode), len);
6175         btrfs_free_reserved_data_space(inode, start, len);
6176 }
6177
6178 static int update_block_group(struct btrfs_trans_handle *trans,
6179                               struct btrfs_fs_info *info, u64 bytenr,
6180                               u64 num_bytes, int alloc)
6181 {
6182         struct btrfs_block_group_cache *cache = NULL;
6183         u64 total = num_bytes;
6184         u64 old_val;
6185         u64 byte_in_group;
6186         int factor;
6187
6188         /* block accounting for super block */
6189         spin_lock(&info->delalloc_root_lock);
6190         old_val = btrfs_super_bytes_used(info->super_copy);
6191         if (alloc)
6192                 old_val += num_bytes;
6193         else
6194                 old_val -= num_bytes;
6195         btrfs_set_super_bytes_used(info->super_copy, old_val);
6196         spin_unlock(&info->delalloc_root_lock);
6197
6198         while (total) {
6199                 cache = btrfs_lookup_block_group(info, bytenr);
6200                 if (!cache)
6201                         return -ENOENT;
6202                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6203                                     BTRFS_BLOCK_GROUP_RAID1 |
6204                                     BTRFS_BLOCK_GROUP_RAID10))
6205                         factor = 2;
6206                 else
6207                         factor = 1;
6208                 /*
6209                  * If this block group has free space cache written out, we
6210                  * need to make sure to load it if we are removing space.  This
6211                  * is because we need the unpinning stage to actually add the
6212                  * space back to the block group, otherwise we will leak space.
6213                  */
6214                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6215                         cache_block_group(cache, 1);
6216
6217                 byte_in_group = bytenr - cache->key.objectid;
6218                 WARN_ON(byte_in_group > cache->key.offset);
6219
6220                 spin_lock(&cache->space_info->lock);
6221                 spin_lock(&cache->lock);
6222
6223                 if (btrfs_test_opt(info, SPACE_CACHE) &&
6224                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6225                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6226
6227                 old_val = btrfs_block_group_used(&cache->item);
6228                 num_bytes = min(total, cache->key.offset - byte_in_group);
6229                 if (alloc) {
6230                         old_val += num_bytes;
6231                         btrfs_set_block_group_used(&cache->item, old_val);
6232                         cache->reserved -= num_bytes;
6233                         cache->space_info->bytes_reserved -= num_bytes;
6234                         cache->space_info->bytes_used += num_bytes;
6235                         cache->space_info->disk_used += num_bytes * factor;
6236                         spin_unlock(&cache->lock);
6237                         spin_unlock(&cache->space_info->lock);
6238                 } else {
6239                         old_val -= num_bytes;
6240                         btrfs_set_block_group_used(&cache->item, old_val);
6241                         cache->pinned += num_bytes;
6242                         cache->space_info->bytes_pinned += num_bytes;
6243                         cache->space_info->bytes_used -= num_bytes;
6244                         cache->space_info->disk_used -= num_bytes * factor;
6245                         spin_unlock(&cache->lock);
6246                         spin_unlock(&cache->space_info->lock);
6247
6248                         trace_btrfs_space_reservation(info, "pinned",
6249                                                       cache->space_info->flags,
6250                                                       num_bytes, 1);
6251                         set_extent_dirty(info->pinned_extents,
6252                                          bytenr, bytenr + num_bytes - 1,
6253                                          GFP_NOFS | __GFP_NOFAIL);
6254                 }
6255
6256                 spin_lock(&trans->transaction->dirty_bgs_lock);
6257                 if (list_empty(&cache->dirty_list)) {
6258                         list_add_tail(&cache->dirty_list,
6259                                       &trans->transaction->dirty_bgs);
6260                                 trans->transaction->num_dirty_bgs++;
6261                         btrfs_get_block_group(cache);
6262                 }
6263                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6264
6265                 /*
6266                  * No longer have used bytes in this block group, queue it for
6267                  * deletion. We do this after adding the block group to the
6268                  * dirty list to avoid races between cleaner kthread and space
6269                  * cache writeout.
6270                  */
6271                 if (!alloc && old_val == 0) {
6272                         spin_lock(&info->unused_bgs_lock);
6273                         if (list_empty(&cache->bg_list)) {
6274                                 btrfs_get_block_group(cache);
6275                                 list_add_tail(&cache->bg_list,
6276                                               &info->unused_bgs);
6277                         }
6278                         spin_unlock(&info->unused_bgs_lock);
6279                 }
6280
6281                 btrfs_put_block_group(cache);
6282                 total -= num_bytes;
6283                 bytenr += num_bytes;
6284         }
6285         return 0;
6286 }
6287
6288 static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
6289 {
6290         struct btrfs_block_group_cache *cache;
6291         u64 bytenr;
6292
6293         spin_lock(&fs_info->block_group_cache_lock);
6294         bytenr = fs_info->first_logical_byte;
6295         spin_unlock(&fs_info->block_group_cache_lock);
6296
6297         if (bytenr < (u64)-1)
6298                 return bytenr;
6299
6300         cache = btrfs_lookup_first_block_group(fs_info, search_start);
6301         if (!cache)
6302                 return 0;
6303
6304         bytenr = cache->key.objectid;
6305         btrfs_put_block_group(cache);
6306
6307         return bytenr;
6308 }
6309
6310 static int pin_down_extent(struct btrfs_fs_info *fs_info,
6311                            struct btrfs_block_group_cache *cache,
6312                            u64 bytenr, u64 num_bytes, int reserved)
6313 {
6314         spin_lock(&cache->space_info->lock);
6315         spin_lock(&cache->lock);
6316         cache->pinned += num_bytes;
6317         cache->space_info->bytes_pinned += num_bytes;
6318         if (reserved) {
6319                 cache->reserved -= num_bytes;
6320                 cache->space_info->bytes_reserved -= num_bytes;
6321         }
6322         spin_unlock(&cache->lock);
6323         spin_unlock(&cache->space_info->lock);
6324
6325         trace_btrfs_space_reservation(fs_info, "pinned",
6326                                       cache->space_info->flags, num_bytes, 1);
6327         set_extent_dirty(fs_info->pinned_extents, bytenr,
6328                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6329         return 0;
6330 }
6331
6332 /*
6333  * this function must be called within transaction
6334  */
6335 int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
6336                      u64 bytenr, u64 num_bytes, int reserved)
6337 {
6338         struct btrfs_block_group_cache *cache;
6339
6340         cache = btrfs_lookup_block_group(fs_info, bytenr);
6341         BUG_ON(!cache); /* Logic error */
6342
6343         pin_down_extent(fs_info, cache, bytenr, num_bytes, reserved);
6344
6345         btrfs_put_block_group(cache);
6346         return 0;
6347 }
6348
6349 /*
6350  * this function must be called within transaction
6351  */
6352 int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
6353                                     u64 bytenr, u64 num_bytes)
6354 {
6355         struct btrfs_block_group_cache *cache;
6356         int ret;
6357
6358         cache = btrfs_lookup_block_group(fs_info, bytenr);
6359         if (!cache)
6360                 return -EINVAL;
6361
6362         /*
6363          * pull in the free space cache (if any) so that our pin
6364          * removes the free space from the cache.  We have load_only set
6365          * to one because the slow code to read in the free extents does check
6366          * the pinned extents.
6367          */
6368         cache_block_group(cache, 1);
6369
6370         pin_down_extent(fs_info, cache, bytenr, num_bytes, 0);
6371
6372         /* remove us from the free space cache (if we're there at all) */
6373         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6374         btrfs_put_block_group(cache);
6375         return ret;
6376 }
6377
6378 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
6379                                    u64 start, u64 num_bytes)
6380 {
6381         int ret;
6382         struct btrfs_block_group_cache *block_group;
6383         struct btrfs_caching_control *caching_ctl;
6384
6385         block_group = btrfs_lookup_block_group(fs_info, start);
6386         if (!block_group)
6387                 return -EINVAL;
6388
6389         cache_block_group(block_group, 0);
6390         caching_ctl = get_caching_control(block_group);
6391
6392         if (!caching_ctl) {
6393                 /* Logic error */
6394                 BUG_ON(!block_group_cache_done(block_group));
6395                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6396         } else {
6397                 mutex_lock(&caching_ctl->mutex);
6398
6399                 if (start >= caching_ctl->progress) {
6400                         ret = add_excluded_extent(fs_info, start, num_bytes);
6401                 } else if (start + num_bytes <= caching_ctl->progress) {
6402                         ret = btrfs_remove_free_space(block_group,
6403                                                       start, num_bytes);
6404                 } else {
6405                         num_bytes = caching_ctl->progress - start;
6406                         ret = btrfs_remove_free_space(block_group,
6407                                                       start, num_bytes);
6408                         if (ret)
6409                                 goto out_lock;
6410
6411                         num_bytes = (start + num_bytes) -
6412                                 caching_ctl->progress;
6413                         start = caching_ctl->progress;
6414                         ret = add_excluded_extent(fs_info, start, num_bytes);
6415                 }
6416 out_lock:
6417                 mutex_unlock(&caching_ctl->mutex);
6418                 put_caching_control(caching_ctl);
6419         }
6420         btrfs_put_block_group(block_group);
6421         return ret;
6422 }
6423
6424 int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
6425                                  struct extent_buffer *eb)
6426 {
6427         struct btrfs_file_extent_item *item;
6428         struct btrfs_key key;
6429         int found_type;
6430         int i;
6431
6432         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
6433                 return 0;
6434
6435         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6436                 btrfs_item_key_to_cpu(eb, &key, i);
6437                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6438                         continue;
6439                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6440                 found_type = btrfs_file_extent_type(eb, item);
6441                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6442                         continue;
6443                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6444                         continue;
6445                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6446                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6447                 __exclude_logged_extent(fs_info, key.objectid, key.offset);
6448         }
6449
6450         return 0;
6451 }
6452
6453 static void
6454 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6455 {
6456         atomic_inc(&bg->reservations);
6457 }
6458
6459 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6460                                         const u64 start)
6461 {
6462         struct btrfs_block_group_cache *bg;
6463
6464         bg = btrfs_lookup_block_group(fs_info, start);
6465         ASSERT(bg);
6466         if (atomic_dec_and_test(&bg->reservations))
6467                 wake_up_atomic_t(&bg->reservations);
6468         btrfs_put_block_group(bg);
6469 }
6470
6471 static int btrfs_wait_bg_reservations_atomic_t(atomic_t *a)
6472 {
6473         schedule();
6474         return 0;
6475 }
6476
6477 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6478 {
6479         struct btrfs_space_info *space_info = bg->space_info;
6480
6481         ASSERT(bg->ro);
6482
6483         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6484                 return;
6485
6486         /*
6487          * Our block group is read only but before we set it to read only,
6488          * some task might have had allocated an extent from it already, but it
6489          * has not yet created a respective ordered extent (and added it to a
6490          * root's list of ordered extents).
6491          * Therefore wait for any task currently allocating extents, since the
6492          * block group's reservations counter is incremented while a read lock
6493          * on the groups' semaphore is held and decremented after releasing
6494          * the read access on that semaphore and creating the ordered extent.
6495          */
6496         down_write(&space_info->groups_sem);
6497         up_write(&space_info->groups_sem);
6498
6499         wait_on_atomic_t(&bg->reservations,
6500                          btrfs_wait_bg_reservations_atomic_t,
6501                          TASK_UNINTERRUPTIBLE);
6502 }
6503
6504 /**
6505  * btrfs_add_reserved_bytes - update the block_group and space info counters
6506  * @cache:      The cache we are manipulating
6507  * @ram_bytes:  The number of bytes of file content, and will be same to
6508  *              @num_bytes except for the compress path.
6509  * @num_bytes:  The number of bytes in question
6510  * @delalloc:   The blocks are allocated for the delalloc write
6511  *
6512  * This is called by the allocator when it reserves space. If this is a
6513  * reservation and the block group has become read only we cannot make the
6514  * reservation and return -EAGAIN, otherwise this function always succeeds.
6515  */
6516 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6517                                     u64 ram_bytes, u64 num_bytes, int delalloc)
6518 {
6519         struct btrfs_space_info *space_info = cache->space_info;
6520         int ret = 0;
6521
6522         spin_lock(&space_info->lock);
6523         spin_lock(&cache->lock);
6524         if (cache->ro) {
6525                 ret = -EAGAIN;
6526         } else {
6527                 cache->reserved += num_bytes;
6528                 space_info->bytes_reserved += num_bytes;
6529
6530                 trace_btrfs_space_reservation(cache->fs_info,
6531                                 "space_info", space_info->flags,
6532                                 ram_bytes, 0);
6533                 space_info->bytes_may_use -= ram_bytes;
6534                 if (delalloc)
6535                         cache->delalloc_bytes += num_bytes;
6536         }
6537         spin_unlock(&cache->lock);
6538         spin_unlock(&space_info->lock);
6539         return ret;
6540 }
6541
6542 /**
6543  * btrfs_free_reserved_bytes - update the block_group and space info counters
6544  * @cache:      The cache we are manipulating
6545  * @num_bytes:  The number of bytes in question
6546  * @delalloc:   The blocks are allocated for the delalloc write
6547  *
6548  * This is called by somebody who is freeing space that was never actually used
6549  * on disk.  For example if you reserve some space for a new leaf in transaction
6550  * A and before transaction A commits you free that leaf, you call this with
6551  * reserve set to 0 in order to clear the reservation.
6552  */
6553
6554 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6555                                      u64 num_bytes, int delalloc)
6556 {
6557         struct btrfs_space_info *space_info = cache->space_info;
6558         int ret = 0;
6559
6560         spin_lock(&space_info->lock);
6561         spin_lock(&cache->lock);
6562         if (cache->ro)
6563                 space_info->bytes_readonly += num_bytes;
6564         cache->reserved -= num_bytes;
6565         space_info->bytes_reserved -= num_bytes;
6566
6567         if (delalloc)
6568                 cache->delalloc_bytes -= num_bytes;
6569         spin_unlock(&cache->lock);
6570         spin_unlock(&space_info->lock);
6571         return ret;
6572 }
6573 void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
6574 {
6575         struct btrfs_caching_control *next;
6576         struct btrfs_caching_control *caching_ctl;
6577         struct btrfs_block_group_cache *cache;
6578
6579         down_write(&fs_info->commit_root_sem);
6580
6581         list_for_each_entry_safe(caching_ctl, next,
6582                                  &fs_info->caching_block_groups, list) {
6583                 cache = caching_ctl->block_group;
6584                 if (block_group_cache_done(cache)) {
6585                         cache->last_byte_to_unpin = (u64)-1;
6586                         list_del_init(&caching_ctl->list);
6587                         put_caching_control(caching_ctl);
6588                 } else {
6589                         cache->last_byte_to_unpin = caching_ctl->progress;
6590                 }
6591         }
6592
6593         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6594                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6595         else
6596                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6597
6598         up_write(&fs_info->commit_root_sem);
6599
6600         update_global_block_rsv(fs_info);
6601 }
6602
6603 /*
6604  * Returns the free cluster for the given space info and sets empty_cluster to
6605  * what it should be based on the mount options.
6606  */
6607 static struct btrfs_free_cluster *
6608 fetch_cluster_info(struct btrfs_fs_info *fs_info,
6609                    struct btrfs_space_info *space_info, u64 *empty_cluster)
6610 {
6611         struct btrfs_free_cluster *ret = NULL;
6612         bool ssd = btrfs_test_opt(fs_info, SSD);
6613
6614         *empty_cluster = 0;
6615         if (btrfs_mixed_space_info(space_info))
6616                 return ret;
6617
6618         if (ssd)
6619                 *empty_cluster = SZ_2M;
6620         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6621                 ret = &fs_info->meta_alloc_cluster;
6622                 if (!ssd)
6623                         *empty_cluster = SZ_64K;
6624         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) && ssd) {
6625                 ret = &fs_info->data_alloc_cluster;
6626         }
6627
6628         return ret;
6629 }
6630
6631 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
6632                               u64 start, u64 end,
6633                               const bool return_free_space)
6634 {
6635         struct btrfs_block_group_cache *cache = NULL;
6636         struct btrfs_space_info *space_info;
6637         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6638         struct btrfs_free_cluster *cluster = NULL;
6639         u64 len;
6640         u64 total_unpinned = 0;
6641         u64 empty_cluster = 0;
6642         bool readonly;
6643
6644         while (start <= end) {
6645                 readonly = false;
6646                 if (!cache ||
6647                     start >= cache->key.objectid + cache->key.offset) {
6648                         if (cache)
6649                                 btrfs_put_block_group(cache);
6650                         total_unpinned = 0;
6651                         cache = btrfs_lookup_block_group(fs_info, start);
6652                         BUG_ON(!cache); /* Logic error */
6653
6654                         cluster = fetch_cluster_info(fs_info,
6655                                                      cache->space_info,
6656                                                      &empty_cluster);
6657                         empty_cluster <<= 1;
6658                 }
6659
6660                 len = cache->key.objectid + cache->key.offset - start;
6661                 len = min(len, end + 1 - start);
6662
6663                 if (start < cache->last_byte_to_unpin) {
6664                         len = min(len, cache->last_byte_to_unpin - start);
6665                         if (return_free_space)
6666                                 btrfs_add_free_space(cache, start, len);
6667                 }
6668
6669                 start += len;
6670                 total_unpinned += len;
6671                 space_info = cache->space_info;
6672
6673                 /*
6674                  * If this space cluster has been marked as fragmented and we've
6675                  * unpinned enough in this block group to potentially allow a
6676                  * cluster to be created inside of it go ahead and clear the
6677                  * fragmented check.
6678                  */
6679                 if (cluster && cluster->fragmented &&
6680                     total_unpinned > empty_cluster) {
6681                         spin_lock(&cluster->lock);
6682                         cluster->fragmented = 0;
6683                         spin_unlock(&cluster->lock);
6684                 }
6685
6686                 spin_lock(&space_info->lock);
6687                 spin_lock(&cache->lock);
6688                 cache->pinned -= len;
6689                 space_info->bytes_pinned -= len;
6690
6691                 trace_btrfs_space_reservation(fs_info, "pinned",
6692                                               space_info->flags, len, 0);
6693                 space_info->max_extent_size = 0;
6694                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6695                 if (cache->ro) {
6696                         space_info->bytes_readonly += len;
6697                         readonly = true;
6698                 }
6699                 spin_unlock(&cache->lock);
6700                 if (!readonly && return_free_space &&
6701                     global_rsv->space_info == space_info) {
6702                         u64 to_add = len;
6703                         WARN_ON(!return_free_space);
6704                         spin_lock(&global_rsv->lock);
6705                         if (!global_rsv->full) {
6706                                 to_add = min(len, global_rsv->size -
6707                                              global_rsv->reserved);
6708                                 global_rsv->reserved += to_add;
6709                                 space_info->bytes_may_use += to_add;
6710                                 if (global_rsv->reserved >= global_rsv->size)
6711                                         global_rsv->full = 1;
6712                                 trace_btrfs_space_reservation(fs_info,
6713                                                               "space_info",
6714                                                               space_info->flags,
6715                                                               to_add, 1);
6716                                 len -= to_add;
6717                         }
6718                         spin_unlock(&global_rsv->lock);
6719                         /* Add to any tickets we may have */
6720                         if (len)
6721                                 space_info_add_new_bytes(fs_info, space_info,
6722                                                          len);
6723                 }
6724                 spin_unlock(&space_info->lock);
6725         }
6726
6727         if (cache)
6728                 btrfs_put_block_group(cache);
6729         return 0;
6730 }
6731
6732 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6733                                struct btrfs_fs_info *fs_info)
6734 {
6735         struct btrfs_block_group_cache *block_group, *tmp;
6736         struct list_head *deleted_bgs;
6737         struct extent_io_tree *unpin;
6738         u64 start;
6739         u64 end;
6740         int ret;
6741
6742         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6743                 unpin = &fs_info->freed_extents[1];
6744         else
6745                 unpin = &fs_info->freed_extents[0];
6746
6747         while (!trans->aborted) {
6748                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6749                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6750                                             EXTENT_DIRTY, NULL);
6751                 if (ret) {
6752                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6753                         break;
6754                 }
6755
6756                 if (btrfs_test_opt(fs_info, DISCARD))
6757                         ret = btrfs_discard_extent(fs_info, start,
6758                                                    end + 1 - start, NULL);
6759
6760                 clear_extent_dirty(unpin, start, end);
6761                 unpin_extent_range(fs_info, start, end, true);
6762                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6763                 cond_resched();
6764         }
6765
6766         /*
6767          * Transaction is finished.  We don't need the lock anymore.  We
6768          * do need to clean up the block groups in case of a transaction
6769          * abort.
6770          */
6771         deleted_bgs = &trans->transaction->deleted_bgs;
6772         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6773                 u64 trimmed = 0;
6774
6775                 ret = -EROFS;
6776                 if (!trans->aborted)
6777                         ret = btrfs_discard_extent(fs_info,
6778                                                    block_group->key.objectid,
6779                                                    block_group->key.offset,
6780                                                    &trimmed);
6781
6782                 list_del_init(&block_group->bg_list);
6783                 btrfs_put_block_group_trimming(block_group);
6784                 btrfs_put_block_group(block_group);
6785
6786                 if (ret) {
6787                         const char *errstr = btrfs_decode_error(ret);
6788                         btrfs_warn(fs_info,
6789                                    "Discard failed while removing blockgroup: errno=%d %s\n",
6790                                    ret, errstr);
6791                 }
6792         }
6793
6794         return 0;
6795 }
6796
6797 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6798                              u64 owner, u64 root_objectid)
6799 {
6800         struct btrfs_space_info *space_info;
6801         u64 flags;
6802
6803         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6804                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6805                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
6806                 else
6807                         flags = BTRFS_BLOCK_GROUP_METADATA;
6808         } else {
6809                 flags = BTRFS_BLOCK_GROUP_DATA;
6810         }
6811
6812         space_info = __find_space_info(fs_info, flags);
6813         BUG_ON(!space_info); /* Logic bug */
6814         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6815 }
6816
6817
6818 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6819                                 struct btrfs_fs_info *info,
6820                                 struct btrfs_delayed_ref_node *node, u64 parent,
6821                                 u64 root_objectid, u64 owner_objectid,
6822                                 u64 owner_offset, int refs_to_drop,
6823                                 struct btrfs_delayed_extent_op *extent_op)
6824 {
6825         struct btrfs_key key;
6826         struct btrfs_path *path;
6827         struct btrfs_root *extent_root = info->extent_root;
6828         struct extent_buffer *leaf;
6829         struct btrfs_extent_item *ei;
6830         struct btrfs_extent_inline_ref *iref;
6831         int ret;
6832         int is_data;
6833         int extent_slot = 0;
6834         int found_extent = 0;
6835         int num_to_del = 1;
6836         u32 item_size;
6837         u64 refs;
6838         u64 bytenr = node->bytenr;
6839         u64 num_bytes = node->num_bytes;
6840         int last_ref = 0;
6841         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
6842
6843         path = btrfs_alloc_path();
6844         if (!path)
6845                 return -ENOMEM;
6846
6847         path->reada = READA_FORWARD;
6848         path->leave_spinning = 1;
6849
6850         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6851         BUG_ON(!is_data && refs_to_drop != 1);
6852
6853         if (is_data)
6854                 skinny_metadata = 0;
6855
6856         ret = lookup_extent_backref(trans, info, path, &iref,
6857                                     bytenr, num_bytes, parent,
6858                                     root_objectid, owner_objectid,
6859                                     owner_offset);
6860         if (ret == 0) {
6861                 extent_slot = path->slots[0];
6862                 while (extent_slot >= 0) {
6863                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6864                                               extent_slot);
6865                         if (key.objectid != bytenr)
6866                                 break;
6867                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6868                             key.offset == num_bytes) {
6869                                 found_extent = 1;
6870                                 break;
6871                         }
6872                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6873                             key.offset == owner_objectid) {
6874                                 found_extent = 1;
6875                                 break;
6876                         }
6877                         if (path->slots[0] - extent_slot > 5)
6878                                 break;
6879                         extent_slot--;
6880                 }
6881 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6882                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6883                 if (found_extent && item_size < sizeof(*ei))
6884                         found_extent = 0;
6885 #endif
6886                 if (!found_extent) {
6887                         BUG_ON(iref);
6888                         ret = remove_extent_backref(trans, info, path, NULL,
6889                                                     refs_to_drop,
6890                                                     is_data, &last_ref);
6891                         if (ret) {
6892                                 btrfs_abort_transaction(trans, ret);
6893                                 goto out;
6894                         }
6895                         btrfs_release_path(path);
6896                         path->leave_spinning = 1;
6897
6898                         key.objectid = bytenr;
6899                         key.type = BTRFS_EXTENT_ITEM_KEY;
6900                         key.offset = num_bytes;
6901
6902                         if (!is_data && skinny_metadata) {
6903                                 key.type = BTRFS_METADATA_ITEM_KEY;
6904                                 key.offset = owner_objectid;
6905                         }
6906
6907                         ret = btrfs_search_slot(trans, extent_root,
6908                                                 &key, path, -1, 1);
6909                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6910                                 /*
6911                                  * Couldn't find our skinny metadata item,
6912                                  * see if we have ye olde extent item.
6913                                  */
6914                                 path->slots[0]--;
6915                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6916                                                       path->slots[0]);
6917                                 if (key.objectid == bytenr &&
6918                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6919                                     key.offset == num_bytes)
6920                                         ret = 0;
6921                         }
6922
6923                         if (ret > 0 && skinny_metadata) {
6924                                 skinny_metadata = false;
6925                                 key.objectid = bytenr;
6926                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6927                                 key.offset = num_bytes;
6928                                 btrfs_release_path(path);
6929                                 ret = btrfs_search_slot(trans, extent_root,
6930                                                         &key, path, -1, 1);
6931                         }
6932
6933                         if (ret) {
6934                                 btrfs_err(info,
6935                                           "umm, got %d back from search, was looking for %llu",
6936                                           ret, bytenr);
6937                                 if (ret > 0)
6938                                         btrfs_print_leaf(info, path->nodes[0]);
6939                         }
6940                         if (ret < 0) {
6941                                 btrfs_abort_transaction(trans, ret);
6942                                 goto out;
6943                         }
6944                         extent_slot = path->slots[0];
6945                 }
6946         } else if (WARN_ON(ret == -ENOENT)) {
6947                 btrfs_print_leaf(info, path->nodes[0]);
6948                 btrfs_err(info,
6949                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6950                         bytenr, parent, root_objectid, owner_objectid,
6951                         owner_offset);
6952                 btrfs_abort_transaction(trans, ret);
6953                 goto out;
6954         } else {
6955                 btrfs_abort_transaction(trans, ret);
6956                 goto out;
6957         }
6958
6959         leaf = path->nodes[0];
6960         item_size = btrfs_item_size_nr(leaf, extent_slot);
6961 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6962         if (item_size < sizeof(*ei)) {
6963                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6964                 ret = convert_extent_item_v0(trans, info, path, owner_objectid,
6965                                              0);
6966                 if (ret < 0) {
6967                         btrfs_abort_transaction(trans, ret);
6968                         goto out;
6969                 }
6970
6971                 btrfs_release_path(path);
6972                 path->leave_spinning = 1;
6973
6974                 key.objectid = bytenr;
6975                 key.type = BTRFS_EXTENT_ITEM_KEY;
6976                 key.offset = num_bytes;
6977
6978                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6979                                         -1, 1);
6980                 if (ret) {
6981                         btrfs_err(info,
6982                                   "umm, got %d back from search, was looking for %llu",
6983                                 ret, bytenr);
6984                         btrfs_print_leaf(info, path->nodes[0]);
6985                 }
6986                 if (ret < 0) {
6987                         btrfs_abort_transaction(trans, ret);
6988                         goto out;
6989                 }
6990
6991                 extent_slot = path->slots[0];
6992                 leaf = path->nodes[0];
6993                 item_size = btrfs_item_size_nr(leaf, extent_slot);
6994         }
6995 #endif
6996         BUG_ON(item_size < sizeof(*ei));
6997         ei = btrfs_item_ptr(leaf, extent_slot,
6998                             struct btrfs_extent_item);
6999         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
7000             key.type == BTRFS_EXTENT_ITEM_KEY) {
7001                 struct btrfs_tree_block_info *bi;
7002                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
7003                 bi = (struct btrfs_tree_block_info *)(ei + 1);
7004                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
7005         }
7006
7007         refs = btrfs_extent_refs(leaf, ei);
7008         if (refs < refs_to_drop) {
7009                 btrfs_err(info,
7010                           "trying to drop %d refs but we only have %Lu for bytenr %Lu",
7011                           refs_to_drop, refs, bytenr);
7012                 ret = -EINVAL;
7013                 btrfs_abort_transaction(trans, ret);
7014                 goto out;
7015         }
7016         refs -= refs_to_drop;
7017
7018         if (refs > 0) {
7019                 if (extent_op)
7020                         __run_delayed_extent_op(extent_op, leaf, ei);
7021                 /*
7022                  * In the case of inline back ref, reference count will
7023                  * be updated by remove_extent_backref
7024                  */
7025                 if (iref) {
7026                         BUG_ON(!found_extent);
7027                 } else {
7028                         btrfs_set_extent_refs(leaf, ei, refs);
7029                         btrfs_mark_buffer_dirty(leaf);
7030                 }
7031                 if (found_extent) {
7032                         ret = remove_extent_backref(trans, info, path,
7033                                                     iref, refs_to_drop,
7034                                                     is_data, &last_ref);
7035                         if (ret) {
7036                                 btrfs_abort_transaction(trans, ret);
7037                                 goto out;
7038                         }
7039                 }
7040                 add_pinned_bytes(info, -num_bytes, owner_objectid,
7041                                  root_objectid);
7042         } else {
7043                 if (found_extent) {
7044                         BUG_ON(is_data && refs_to_drop !=
7045                                extent_data_ref_count(path, iref));
7046                         if (iref) {
7047                                 BUG_ON(path->slots[0] != extent_slot);
7048                         } else {
7049                                 BUG_ON(path->slots[0] != extent_slot + 1);
7050                                 path->slots[0] = extent_slot;
7051                                 num_to_del = 2;
7052                         }
7053                 }
7054
7055                 last_ref = 1;
7056                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
7057                                       num_to_del);
7058                 if (ret) {
7059                         btrfs_abort_transaction(trans, ret);
7060                         goto out;
7061                 }
7062                 btrfs_release_path(path);
7063
7064                 if (is_data) {
7065                         ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
7066                         if (ret) {
7067                                 btrfs_abort_transaction(trans, ret);
7068                                 goto out;
7069                         }
7070                 }
7071
7072                 ret = add_to_free_space_tree(trans, info, bytenr, num_bytes);
7073                 if (ret) {
7074                         btrfs_abort_transaction(trans, ret);
7075                         goto out;
7076                 }
7077
7078                 ret = update_block_group(trans, info, bytenr, num_bytes, 0);
7079                 if (ret) {
7080                         btrfs_abort_transaction(trans, ret);
7081                         goto out;
7082                 }
7083         }
7084         btrfs_release_path(path);
7085
7086 out:
7087         btrfs_free_path(path);
7088         return ret;
7089 }
7090
7091 /*
7092  * when we free an block, it is possible (and likely) that we free the last
7093  * delayed ref for that extent as well.  This searches the delayed ref tree for
7094  * a given extent, and if there are no other delayed refs to be processed, it
7095  * removes it from the tree.
7096  */
7097 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
7098                                       u64 bytenr)
7099 {
7100         struct btrfs_delayed_ref_head *head;
7101         struct btrfs_delayed_ref_root *delayed_refs;
7102         int ret = 0;
7103
7104         delayed_refs = &trans->transaction->delayed_refs;
7105         spin_lock(&delayed_refs->lock);
7106         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
7107         if (!head)
7108                 goto out_delayed_unlock;
7109
7110         spin_lock(&head->lock);
7111         if (!list_empty(&head->ref_list))
7112                 goto out;
7113
7114         if (head->extent_op) {
7115                 if (!head->must_insert_reserved)
7116                         goto out;
7117                 btrfs_free_delayed_extent_op(head->extent_op);
7118                 head->extent_op = NULL;
7119         }
7120
7121         /*
7122          * waiting for the lock here would deadlock.  If someone else has it
7123          * locked they are already in the process of dropping it anyway
7124          */
7125         if (!mutex_trylock(&head->mutex))
7126                 goto out;
7127
7128         /*
7129          * at this point we have a head with no other entries.  Go
7130          * ahead and process it.
7131          */
7132         head->node.in_tree = 0;
7133         rb_erase(&head->href_node, &delayed_refs->href_root);
7134
7135         atomic_dec(&delayed_refs->num_entries);
7136
7137         /*
7138          * we don't take a ref on the node because we're removing it from the
7139          * tree, so we just steal the ref the tree was holding.
7140          */
7141         delayed_refs->num_heads--;
7142         if (head->processing == 0)
7143                 delayed_refs->num_heads_ready--;
7144         head->processing = 0;
7145         spin_unlock(&head->lock);
7146         spin_unlock(&delayed_refs->lock);
7147
7148         BUG_ON(head->extent_op);
7149         if (head->must_insert_reserved)
7150                 ret = 1;
7151
7152         mutex_unlock(&head->mutex);
7153         btrfs_put_delayed_ref(&head->node);
7154         return ret;
7155 out:
7156         spin_unlock(&head->lock);
7157
7158 out_delayed_unlock:
7159         spin_unlock(&delayed_refs->lock);
7160         return 0;
7161 }
7162
7163 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7164                            struct btrfs_root *root,
7165                            struct extent_buffer *buf,
7166                            u64 parent, int last_ref)
7167 {
7168         struct btrfs_fs_info *fs_info = root->fs_info;
7169         int pin = 1;
7170         int ret;
7171
7172         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7173                 ret = btrfs_add_delayed_tree_ref(fs_info, trans,
7174                                                  buf->start, buf->len,
7175                                                  parent,
7176                                                  root->root_key.objectid,
7177                                                  btrfs_header_level(buf),
7178                                                  BTRFS_DROP_DELAYED_REF, NULL);
7179                 BUG_ON(ret); /* -ENOMEM */
7180         }
7181
7182         if (!last_ref)
7183                 return;
7184
7185         if (btrfs_header_generation(buf) == trans->transid) {
7186                 struct btrfs_block_group_cache *cache;
7187
7188                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7189                         ret = check_ref_cleanup(trans, buf->start);
7190                         if (!ret)
7191                                 goto out;
7192                 }
7193
7194                 cache = btrfs_lookup_block_group(fs_info, buf->start);
7195
7196                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7197                         pin_down_extent(fs_info, cache, buf->start,
7198                                         buf->len, 1);
7199                         btrfs_put_block_group(cache);
7200                         goto out;
7201                 }
7202
7203                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7204
7205                 btrfs_add_free_space(cache, buf->start, buf->len);
7206                 btrfs_free_reserved_bytes(cache, buf->len, 0);
7207                 btrfs_put_block_group(cache);
7208                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
7209                 pin = 0;
7210         }
7211 out:
7212         if (pin)
7213                 add_pinned_bytes(fs_info, buf->len, btrfs_header_level(buf),
7214                                  root->root_key.objectid);
7215
7216         /*
7217          * Deleting the buffer, clear the corrupt flag since it doesn't matter
7218          * anymore.
7219          */
7220         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7221 }
7222
7223 /* Can return -ENOMEM */
7224 int btrfs_free_extent(struct btrfs_trans_handle *trans,
7225                       struct btrfs_fs_info *fs_info,
7226                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7227                       u64 owner, u64 offset)
7228 {
7229         int ret;
7230
7231         if (btrfs_is_testing(fs_info))
7232                 return 0;
7233
7234         add_pinned_bytes(fs_info, num_bytes, owner, root_objectid);
7235
7236         /*
7237          * tree log blocks never actually go into the extent allocation
7238          * tree, just update pinning info and exit early.
7239          */
7240         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7241                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7242                 /* unlocks the pinned mutex */
7243                 btrfs_pin_extent(fs_info, bytenr, num_bytes, 1);
7244                 ret = 0;
7245         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7246                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7247                                         num_bytes,
7248                                         parent, root_objectid, (int)owner,
7249                                         BTRFS_DROP_DELAYED_REF, NULL);
7250         } else {
7251                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7252                                                 num_bytes,
7253                                                 parent, root_objectid, owner,
7254                                                 offset, 0,
7255                                                 BTRFS_DROP_DELAYED_REF);
7256         }
7257         return ret;
7258 }
7259
7260 /*
7261  * when we wait for progress in the block group caching, its because
7262  * our allocation attempt failed at least once.  So, we must sleep
7263  * and let some progress happen before we try again.
7264  *
7265  * This function will sleep at least once waiting for new free space to
7266  * show up, and then it will check the block group free space numbers
7267  * for our min num_bytes.  Another option is to have it go ahead
7268  * and look in the rbtree for a free extent of a given size, but this
7269  * is a good start.
7270  *
7271  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7272  * any of the information in this block group.
7273  */
7274 static noinline void
7275 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7276                                 u64 num_bytes)
7277 {
7278         struct btrfs_caching_control *caching_ctl;
7279
7280         caching_ctl = get_caching_control(cache);
7281         if (!caching_ctl)
7282                 return;
7283
7284         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7285                    (cache->free_space_ctl->free_space >= num_bytes));
7286
7287         put_caching_control(caching_ctl);
7288 }
7289
7290 static noinline int
7291 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7292 {
7293         struct btrfs_caching_control *caching_ctl;
7294         int ret = 0;
7295
7296         caching_ctl = get_caching_control(cache);
7297         if (!caching_ctl)
7298                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7299
7300         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7301         if (cache->cached == BTRFS_CACHE_ERROR)
7302                 ret = -EIO;
7303         put_caching_control(caching_ctl);
7304         return ret;
7305 }
7306
7307 int __get_raid_index(u64 flags)
7308 {
7309         if (flags & BTRFS_BLOCK_GROUP_RAID10)
7310                 return BTRFS_RAID_RAID10;
7311         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
7312                 return BTRFS_RAID_RAID1;
7313         else if (flags & BTRFS_BLOCK_GROUP_DUP)
7314                 return BTRFS_RAID_DUP;
7315         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
7316                 return BTRFS_RAID_RAID0;
7317         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
7318                 return BTRFS_RAID_RAID5;
7319         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
7320                 return BTRFS_RAID_RAID6;
7321
7322         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
7323 }
7324
7325 int get_block_group_index(struct btrfs_block_group_cache *cache)
7326 {
7327         return __get_raid_index(cache->flags);
7328 }
7329
7330 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
7331         [BTRFS_RAID_RAID10]     = "raid10",
7332         [BTRFS_RAID_RAID1]      = "raid1",
7333         [BTRFS_RAID_DUP]        = "dup",
7334         [BTRFS_RAID_RAID0]      = "raid0",
7335         [BTRFS_RAID_SINGLE]     = "single",
7336         [BTRFS_RAID_RAID5]      = "raid5",
7337         [BTRFS_RAID_RAID6]      = "raid6",
7338 };
7339
7340 static const char *get_raid_name(enum btrfs_raid_types type)
7341 {
7342         if (type >= BTRFS_NR_RAID_TYPES)
7343                 return NULL;
7344
7345         return btrfs_raid_type_names[type];
7346 }
7347
7348 enum btrfs_loop_type {
7349         LOOP_CACHING_NOWAIT = 0,
7350         LOOP_CACHING_WAIT = 1,
7351         LOOP_ALLOC_CHUNK = 2,
7352         LOOP_NO_EMPTY_SIZE = 3,
7353 };
7354
7355 static inline void
7356 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7357                        int delalloc)
7358 {
7359         if (delalloc)
7360                 down_read(&cache->data_rwsem);
7361 }
7362
7363 static inline void
7364 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7365                        int delalloc)
7366 {
7367         btrfs_get_block_group(cache);
7368         if (delalloc)
7369                 down_read(&cache->data_rwsem);
7370 }
7371
7372 static struct btrfs_block_group_cache *
7373 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7374                    struct btrfs_free_cluster *cluster,
7375                    int delalloc)
7376 {
7377         struct btrfs_block_group_cache *used_bg = NULL;
7378
7379         spin_lock(&cluster->refill_lock);
7380         while (1) {
7381                 used_bg = cluster->block_group;
7382                 if (!used_bg)
7383                         return NULL;
7384
7385                 if (used_bg == block_group)
7386                         return used_bg;
7387
7388                 btrfs_get_block_group(used_bg);
7389
7390                 if (!delalloc)
7391                         return used_bg;
7392
7393                 if (down_read_trylock(&used_bg->data_rwsem))
7394                         return used_bg;
7395
7396                 spin_unlock(&cluster->refill_lock);
7397
7398                 /* We should only have one-level nested. */
7399                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
7400
7401                 spin_lock(&cluster->refill_lock);
7402                 if (used_bg == cluster->block_group)
7403                         return used_bg;
7404
7405                 up_read(&used_bg->data_rwsem);
7406                 btrfs_put_block_group(used_bg);
7407         }
7408 }
7409
7410 static inline void
7411 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7412                          int delalloc)
7413 {
7414         if (delalloc)
7415                 up_read(&cache->data_rwsem);
7416         btrfs_put_block_group(cache);
7417 }
7418
7419 /*
7420  * walks the btree of allocated extents and find a hole of a given size.
7421  * The key ins is changed to record the hole:
7422  * ins->objectid == start position
7423  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7424  * ins->offset == the size of the hole.
7425  * Any available blocks before search_start are skipped.
7426  *
7427  * If there is no suitable free space, we will record the max size of
7428  * the free space extent currently.
7429  */
7430 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
7431                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7432                                 u64 hint_byte, struct btrfs_key *ins,
7433                                 u64 flags, int delalloc)
7434 {
7435         int ret = 0;
7436         struct btrfs_root *root = fs_info->extent_root;
7437         struct btrfs_free_cluster *last_ptr = NULL;
7438         struct btrfs_block_group_cache *block_group = NULL;
7439         u64 search_start = 0;
7440         u64 max_extent_size = 0;
7441         u64 empty_cluster = 0;
7442         struct btrfs_space_info *space_info;
7443         int loop = 0;
7444         int index = __get_raid_index(flags);
7445         bool failed_cluster_refill = false;
7446         bool failed_alloc = false;
7447         bool use_cluster = true;
7448         bool have_caching_bg = false;
7449         bool orig_have_caching_bg = false;
7450         bool full_search = false;
7451
7452         WARN_ON(num_bytes < fs_info->sectorsize);
7453         ins->type = BTRFS_EXTENT_ITEM_KEY;
7454         ins->objectid = 0;
7455         ins->offset = 0;
7456
7457         trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
7458
7459         space_info = __find_space_info(fs_info, flags);
7460         if (!space_info) {
7461                 btrfs_err(fs_info, "No space info for %llu", flags);
7462                 return -ENOSPC;
7463         }
7464
7465         /*
7466          * If our free space is heavily fragmented we may not be able to make
7467          * big contiguous allocations, so instead of doing the expensive search
7468          * for free space, simply return ENOSPC with our max_extent_size so we
7469          * can go ahead and search for a more manageable chunk.
7470          *
7471          * If our max_extent_size is large enough for our allocation simply
7472          * disable clustering since we will likely not be able to find enough
7473          * space to create a cluster and induce latency trying.
7474          */
7475         if (unlikely(space_info->max_extent_size)) {
7476                 spin_lock(&space_info->lock);
7477                 if (space_info->max_extent_size &&
7478                     num_bytes > space_info->max_extent_size) {
7479                         ins->offset = space_info->max_extent_size;
7480                         spin_unlock(&space_info->lock);
7481                         return -ENOSPC;
7482                 } else if (space_info->max_extent_size) {
7483                         use_cluster = false;
7484                 }
7485                 spin_unlock(&space_info->lock);
7486         }
7487
7488         last_ptr = fetch_cluster_info(fs_info, space_info, &empty_cluster);
7489         if (last_ptr) {
7490                 spin_lock(&last_ptr->lock);
7491                 if (last_ptr->block_group)
7492                         hint_byte = last_ptr->window_start;
7493                 if (last_ptr->fragmented) {
7494                         /*
7495                          * We still set window_start so we can keep track of the
7496                          * last place we found an allocation to try and save
7497                          * some time.
7498                          */
7499                         hint_byte = last_ptr->window_start;
7500                         use_cluster = false;
7501                 }
7502                 spin_unlock(&last_ptr->lock);
7503         }
7504
7505         search_start = max(search_start, first_logical_byte(fs_info, 0));
7506         search_start = max(search_start, hint_byte);
7507         if (search_start == hint_byte) {
7508                 block_group = btrfs_lookup_block_group(fs_info, search_start);
7509                 /*
7510                  * we don't want to use the block group if it doesn't match our
7511                  * allocation bits, or if its not cached.
7512                  *
7513                  * However if we are re-searching with an ideal block group
7514                  * picked out then we don't care that the block group is cached.
7515                  */
7516                 if (block_group && block_group_bits(block_group, flags) &&
7517                     block_group->cached != BTRFS_CACHE_NO) {
7518                         down_read(&space_info->groups_sem);
7519                         if (list_empty(&block_group->list) ||
7520                             block_group->ro) {
7521                                 /*
7522                                  * someone is removing this block group,
7523                                  * we can't jump into the have_block_group
7524                                  * target because our list pointers are not
7525                                  * valid
7526                                  */
7527                                 btrfs_put_block_group(block_group);
7528                                 up_read(&space_info->groups_sem);
7529                         } else {
7530                                 index = get_block_group_index(block_group);
7531                                 btrfs_lock_block_group(block_group, delalloc);
7532                                 goto have_block_group;
7533                         }
7534                 } else if (block_group) {
7535                         btrfs_put_block_group(block_group);
7536                 }
7537         }
7538 search:
7539         have_caching_bg = false;
7540         if (index == 0 || index == __get_raid_index(flags))
7541                 full_search = true;
7542         down_read(&space_info->groups_sem);
7543         list_for_each_entry(block_group, &space_info->block_groups[index],
7544                             list) {
7545                 u64 offset;
7546                 int cached;
7547
7548                 btrfs_grab_block_group(block_group, delalloc);
7549                 search_start = block_group->key.objectid;
7550
7551                 /*
7552                  * this can happen if we end up cycling through all the
7553                  * raid types, but we want to make sure we only allocate
7554                  * for the proper type.
7555                  */
7556                 if (!block_group_bits(block_group, flags)) {
7557                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
7558                                 BTRFS_BLOCK_GROUP_RAID1 |
7559                                 BTRFS_BLOCK_GROUP_RAID5 |
7560                                 BTRFS_BLOCK_GROUP_RAID6 |
7561                                 BTRFS_BLOCK_GROUP_RAID10;
7562
7563                         /*
7564                          * if they asked for extra copies and this block group
7565                          * doesn't provide them, bail.  This does allow us to
7566                          * fill raid0 from raid1.
7567                          */
7568                         if ((flags & extra) && !(block_group->flags & extra))
7569                                 goto loop;
7570                 }
7571
7572 have_block_group:
7573                 cached = block_group_cache_done(block_group);
7574                 if (unlikely(!cached)) {
7575                         have_caching_bg = true;
7576                         ret = cache_block_group(block_group, 0);
7577                         BUG_ON(ret < 0);
7578                         ret = 0;
7579                 }
7580
7581                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7582                         goto loop;
7583                 if (unlikely(block_group->ro))
7584                         goto loop;
7585
7586                 /*
7587                  * Ok we want to try and use the cluster allocator, so
7588                  * lets look there
7589                  */
7590                 if (last_ptr && use_cluster) {
7591                         struct btrfs_block_group_cache *used_block_group;
7592                         unsigned long aligned_cluster;
7593                         /*
7594                          * the refill lock keeps out other
7595                          * people trying to start a new cluster
7596                          */
7597                         used_block_group = btrfs_lock_cluster(block_group,
7598                                                               last_ptr,
7599                                                               delalloc);
7600                         if (!used_block_group)
7601                                 goto refill_cluster;
7602
7603                         if (used_block_group != block_group &&
7604                             (used_block_group->ro ||
7605                              !block_group_bits(used_block_group, flags)))
7606                                 goto release_cluster;
7607
7608                         offset = btrfs_alloc_from_cluster(used_block_group,
7609                                                 last_ptr,
7610                                                 num_bytes,
7611                                                 used_block_group->key.objectid,
7612                                                 &max_extent_size);
7613                         if (offset) {
7614                                 /* we have a block, we're done */
7615                                 spin_unlock(&last_ptr->refill_lock);
7616                                 trace_btrfs_reserve_extent_cluster(fs_info,
7617                                                 used_block_group,
7618                                                 search_start, num_bytes);
7619                                 if (used_block_group != block_group) {
7620                                         btrfs_release_block_group(block_group,
7621                                                                   delalloc);
7622                                         block_group = used_block_group;
7623                                 }
7624                                 goto checks;
7625                         }
7626
7627                         WARN_ON(last_ptr->block_group != used_block_group);
7628 release_cluster:
7629                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7630                          * set up a new clusters, so lets just skip it
7631                          * and let the allocator find whatever block
7632                          * it can find.  If we reach this point, we
7633                          * will have tried the cluster allocator
7634                          * plenty of times and not have found
7635                          * anything, so we are likely way too
7636                          * fragmented for the clustering stuff to find
7637                          * anything.
7638                          *
7639                          * However, if the cluster is taken from the
7640                          * current block group, release the cluster
7641                          * first, so that we stand a better chance of
7642                          * succeeding in the unclustered
7643                          * allocation.  */
7644                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7645                             used_block_group != block_group) {
7646                                 spin_unlock(&last_ptr->refill_lock);
7647                                 btrfs_release_block_group(used_block_group,
7648                                                           delalloc);
7649                                 goto unclustered_alloc;
7650                         }
7651
7652                         /*
7653                          * this cluster didn't work out, free it and
7654                          * start over
7655                          */
7656                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7657
7658                         if (used_block_group != block_group)
7659                                 btrfs_release_block_group(used_block_group,
7660                                                           delalloc);
7661 refill_cluster:
7662                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7663                                 spin_unlock(&last_ptr->refill_lock);
7664                                 goto unclustered_alloc;
7665                         }
7666
7667                         aligned_cluster = max_t(unsigned long,
7668                                                 empty_cluster + empty_size,
7669                                               block_group->full_stripe_len);
7670
7671                         /* allocate a cluster in this block group */
7672                         ret = btrfs_find_space_cluster(fs_info, block_group,
7673                                                        last_ptr, search_start,
7674                                                        num_bytes,
7675                                                        aligned_cluster);
7676                         if (ret == 0) {
7677                                 /*
7678                                  * now pull our allocation out of this
7679                                  * cluster
7680                                  */
7681                                 offset = btrfs_alloc_from_cluster(block_group,
7682                                                         last_ptr,
7683                                                         num_bytes,
7684                                                         search_start,
7685                                                         &max_extent_size);
7686                                 if (offset) {
7687                                         /* we found one, proceed */
7688                                         spin_unlock(&last_ptr->refill_lock);
7689                                         trace_btrfs_reserve_extent_cluster(fs_info,
7690                                                 block_group, search_start,
7691                                                 num_bytes);
7692                                         goto checks;
7693                                 }
7694                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7695                                    && !failed_cluster_refill) {
7696                                 spin_unlock(&last_ptr->refill_lock);
7697
7698                                 failed_cluster_refill = true;
7699                                 wait_block_group_cache_progress(block_group,
7700                                        num_bytes + empty_cluster + empty_size);
7701                                 goto have_block_group;
7702                         }
7703
7704                         /*
7705                          * at this point we either didn't find a cluster
7706                          * or we weren't able to allocate a block from our
7707                          * cluster.  Free the cluster we've been trying
7708                          * to use, and go to the next block group
7709                          */
7710                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7711                         spin_unlock(&last_ptr->refill_lock);
7712                         goto loop;
7713                 }
7714
7715 unclustered_alloc:
7716                 /*
7717                  * We are doing an unclustered alloc, set the fragmented flag so
7718                  * we don't bother trying to setup a cluster again until we get
7719                  * more space.
7720                  */
7721                 if (unlikely(last_ptr)) {
7722                         spin_lock(&last_ptr->lock);
7723                         last_ptr->fragmented = 1;
7724                         spin_unlock(&last_ptr->lock);
7725                 }
7726                 if (cached) {
7727                         struct btrfs_free_space_ctl *ctl =
7728                                 block_group->free_space_ctl;
7729
7730                         spin_lock(&ctl->tree_lock);
7731                         if (ctl->free_space <
7732                             num_bytes + empty_cluster + empty_size) {
7733                                 if (ctl->free_space > max_extent_size)
7734                                         max_extent_size = ctl->free_space;
7735                                 spin_unlock(&ctl->tree_lock);
7736                                 goto loop;
7737                         }
7738                         spin_unlock(&ctl->tree_lock);
7739                 }
7740
7741                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7742                                                     num_bytes, empty_size,
7743                                                     &max_extent_size);
7744                 /*
7745                  * If we didn't find a chunk, and we haven't failed on this
7746                  * block group before, and this block group is in the middle of
7747                  * caching and we are ok with waiting, then go ahead and wait
7748                  * for progress to be made, and set failed_alloc to true.
7749                  *
7750                  * If failed_alloc is true then we've already waited on this
7751                  * block group once and should move on to the next block group.
7752                  */
7753                 if (!offset && !failed_alloc && !cached &&
7754                     loop > LOOP_CACHING_NOWAIT) {
7755                         wait_block_group_cache_progress(block_group,
7756                                                 num_bytes + empty_size);
7757                         failed_alloc = true;
7758                         goto have_block_group;
7759                 } else if (!offset) {
7760                         goto loop;
7761                 }
7762 checks:
7763                 search_start = ALIGN(offset, fs_info->stripesize);
7764
7765                 /* move on to the next group */
7766                 if (search_start + num_bytes >
7767                     block_group->key.objectid + block_group->key.offset) {
7768                         btrfs_add_free_space(block_group, offset, num_bytes);
7769                         goto loop;
7770                 }
7771
7772                 if (offset < search_start)
7773                         btrfs_add_free_space(block_group, offset,
7774                                              search_start - offset);
7775                 BUG_ON(offset > search_start);
7776
7777                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7778                                 num_bytes, delalloc);
7779                 if (ret == -EAGAIN) {
7780                         btrfs_add_free_space(block_group, offset, num_bytes);
7781                         goto loop;
7782                 }
7783                 btrfs_inc_block_group_reservations(block_group);
7784
7785                 /* we are all good, lets return */
7786                 ins->objectid = search_start;
7787                 ins->offset = num_bytes;
7788
7789                 trace_btrfs_reserve_extent(fs_info, block_group,
7790                                            search_start, num_bytes);
7791                 btrfs_release_block_group(block_group, delalloc);
7792                 break;
7793 loop:
7794                 failed_cluster_refill = false;
7795                 failed_alloc = false;
7796                 BUG_ON(index != get_block_group_index(block_group));
7797                 btrfs_release_block_group(block_group, delalloc);
7798         }
7799         up_read(&space_info->groups_sem);
7800
7801         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7802                 && !orig_have_caching_bg)
7803                 orig_have_caching_bg = true;
7804
7805         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7806                 goto search;
7807
7808         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7809                 goto search;
7810
7811         /*
7812          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7813          *                      caching kthreads as we move along
7814          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7815          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7816          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7817          *                      again
7818          */
7819         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7820                 index = 0;
7821                 if (loop == LOOP_CACHING_NOWAIT) {
7822                         /*
7823                          * We want to skip the LOOP_CACHING_WAIT step if we
7824                          * don't have any uncached bgs and we've already done a
7825                          * full search through.
7826                          */
7827                         if (orig_have_caching_bg || !full_search)
7828                                 loop = LOOP_CACHING_WAIT;
7829                         else
7830                                 loop = LOOP_ALLOC_CHUNK;
7831                 } else {
7832                         loop++;
7833                 }
7834
7835                 if (loop == LOOP_ALLOC_CHUNK) {
7836                         struct btrfs_trans_handle *trans;
7837                         int exist = 0;
7838
7839                         trans = current->journal_info;
7840                         if (trans)
7841                                 exist = 1;
7842                         else
7843                                 trans = btrfs_join_transaction(root);
7844
7845                         if (IS_ERR(trans)) {
7846                                 ret = PTR_ERR(trans);
7847                                 goto out;
7848                         }
7849
7850                         ret = do_chunk_alloc(trans, fs_info, flags,
7851                                              CHUNK_ALLOC_FORCE);
7852
7853                         /*
7854                          * If we can't allocate a new chunk we've already looped
7855                          * through at least once, move on to the NO_EMPTY_SIZE
7856                          * case.
7857                          */
7858                         if (ret == -ENOSPC)
7859                                 loop = LOOP_NO_EMPTY_SIZE;
7860
7861                         /*
7862                          * Do not bail out on ENOSPC since we
7863                          * can do more things.
7864                          */
7865                         if (ret < 0 && ret != -ENOSPC)
7866                                 btrfs_abort_transaction(trans, ret);
7867                         else
7868                                 ret = 0;
7869                         if (!exist)
7870                                 btrfs_end_transaction(trans);
7871                         if (ret)
7872                                 goto out;
7873                 }
7874
7875                 if (loop == LOOP_NO_EMPTY_SIZE) {
7876                         /*
7877                          * Don't loop again if we already have no empty_size and
7878                          * no empty_cluster.
7879                          */
7880                         if (empty_size == 0 &&
7881                             empty_cluster == 0) {
7882                                 ret = -ENOSPC;
7883                                 goto out;
7884                         }
7885                         empty_size = 0;
7886                         empty_cluster = 0;
7887                 }
7888
7889                 goto search;
7890         } else if (!ins->objectid) {
7891                 ret = -ENOSPC;
7892         } else if (ins->objectid) {
7893                 if (!use_cluster && last_ptr) {
7894                         spin_lock(&last_ptr->lock);
7895                         last_ptr->window_start = ins->objectid;
7896                         spin_unlock(&last_ptr->lock);
7897                 }
7898                 ret = 0;
7899         }
7900 out:
7901         if (ret == -ENOSPC) {
7902                 spin_lock(&space_info->lock);
7903                 space_info->max_extent_size = max_extent_size;
7904                 spin_unlock(&space_info->lock);
7905                 ins->offset = max_extent_size;
7906         }
7907         return ret;
7908 }
7909
7910 static void dump_space_info(struct btrfs_fs_info *fs_info,
7911                             struct btrfs_space_info *info, u64 bytes,
7912                             int dump_block_groups)
7913 {
7914         struct btrfs_block_group_cache *cache;
7915         int index = 0;
7916
7917         spin_lock(&info->lock);
7918         btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
7919                    info->flags,
7920                    info->total_bytes - btrfs_space_info_used(info, true),
7921                    info->full ? "" : "not ");
7922         btrfs_info(fs_info,
7923                 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
7924                 info->total_bytes, info->bytes_used, info->bytes_pinned,
7925                 info->bytes_reserved, info->bytes_may_use,
7926                 info->bytes_readonly);
7927         spin_unlock(&info->lock);
7928
7929         if (!dump_block_groups)
7930                 return;
7931
7932         down_read(&info->groups_sem);
7933 again:
7934         list_for_each_entry(cache, &info->block_groups[index], list) {
7935                 spin_lock(&cache->lock);
7936                 btrfs_info(fs_info,
7937                         "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
7938                         cache->key.objectid, cache->key.offset,
7939                         btrfs_block_group_used(&cache->item), cache->pinned,
7940                         cache->reserved, cache->ro ? "[readonly]" : "");
7941                 btrfs_dump_free_space(cache, bytes);
7942                 spin_unlock(&cache->lock);
7943         }
7944         if (++index < BTRFS_NR_RAID_TYPES)
7945                 goto again;
7946         up_read(&info->groups_sem);
7947 }
7948
7949 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
7950                          u64 num_bytes, u64 min_alloc_size,
7951                          u64 empty_size, u64 hint_byte,
7952                          struct btrfs_key *ins, int is_data, int delalloc)
7953 {
7954         struct btrfs_fs_info *fs_info = root->fs_info;
7955         bool final_tried = num_bytes == min_alloc_size;
7956         u64 flags;
7957         int ret;
7958
7959         flags = btrfs_get_alloc_profile(root, is_data);
7960 again:
7961         WARN_ON(num_bytes < fs_info->sectorsize);
7962         ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
7963                                hint_byte, ins, flags, delalloc);
7964         if (!ret && !is_data) {
7965                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
7966         } else if (ret == -ENOSPC) {
7967                 if (!final_tried && ins->offset) {
7968                         num_bytes = min(num_bytes >> 1, ins->offset);
7969                         num_bytes = round_down(num_bytes,
7970                                                fs_info->sectorsize);
7971                         num_bytes = max(num_bytes, min_alloc_size);
7972                         ram_bytes = num_bytes;
7973                         if (num_bytes == min_alloc_size)
7974                                 final_tried = true;
7975                         goto again;
7976                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
7977                         struct btrfs_space_info *sinfo;
7978
7979                         sinfo = __find_space_info(fs_info, flags);
7980                         btrfs_err(fs_info,
7981                                   "allocation failed flags %llu, wanted %llu",
7982                                   flags, num_bytes);
7983                         if (sinfo)
7984                                 dump_space_info(fs_info, sinfo, num_bytes, 1);
7985                 }
7986         }
7987
7988         return ret;
7989 }
7990
7991 static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
7992                                         u64 start, u64 len,
7993                                         int pin, int delalloc)
7994 {
7995         struct btrfs_block_group_cache *cache;
7996         int ret = 0;
7997
7998         cache = btrfs_lookup_block_group(fs_info, start);
7999         if (!cache) {
8000                 btrfs_err(fs_info, "Unable to find block group for %llu",
8001                           start);
8002                 return -ENOSPC;
8003         }
8004
8005         if (pin)
8006                 pin_down_extent(fs_info, cache, start, len, 1);
8007         else {
8008                 if (btrfs_test_opt(fs_info, DISCARD))
8009                         ret = btrfs_discard_extent(fs_info, start, len, NULL);
8010                 btrfs_add_free_space(cache, start, len);
8011                 btrfs_free_reserved_bytes(cache, len, delalloc);
8012                 trace_btrfs_reserved_extent_free(fs_info, start, len);
8013         }
8014
8015         btrfs_put_block_group(cache);
8016         return ret;
8017 }
8018
8019 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8020                                u64 start, u64 len, int delalloc)
8021 {
8022         return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
8023 }
8024
8025 int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
8026                                        u64 start, u64 len)
8027 {
8028         return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
8029 }
8030
8031 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8032                                       struct btrfs_fs_info *fs_info,
8033                                       u64 parent, u64 root_objectid,
8034                                       u64 flags, u64 owner, u64 offset,
8035                                       struct btrfs_key *ins, int ref_mod)
8036 {
8037         int ret;
8038         struct btrfs_extent_item *extent_item;
8039         struct btrfs_extent_inline_ref *iref;
8040         struct btrfs_path *path;
8041         struct extent_buffer *leaf;
8042         int type;
8043         u32 size;
8044
8045         if (parent > 0)
8046                 type = BTRFS_SHARED_DATA_REF_KEY;
8047         else
8048                 type = BTRFS_EXTENT_DATA_REF_KEY;
8049
8050         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8051
8052         path = btrfs_alloc_path();
8053         if (!path)
8054                 return -ENOMEM;
8055
8056         path->leave_spinning = 1;
8057         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8058                                       ins, size);
8059         if (ret) {
8060                 btrfs_free_path(path);
8061                 return ret;
8062         }
8063
8064         leaf = path->nodes[0];
8065         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8066                                      struct btrfs_extent_item);
8067         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8068         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8069         btrfs_set_extent_flags(leaf, extent_item,
8070                                flags | BTRFS_EXTENT_FLAG_DATA);
8071
8072         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8073         btrfs_set_extent_inline_ref_type(leaf, iref, type);
8074         if (parent > 0) {
8075                 struct btrfs_shared_data_ref *ref;
8076                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8077                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8078                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8079         } else {
8080                 struct btrfs_extent_data_ref *ref;
8081                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8082                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8083                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8084                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8085                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8086         }
8087
8088         btrfs_mark_buffer_dirty(path->nodes[0]);
8089         btrfs_free_path(path);
8090
8091         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8092                                           ins->offset);
8093         if (ret)
8094                 return ret;
8095
8096         ret = update_block_group(trans, fs_info, ins->objectid, ins->offset, 1);
8097         if (ret) { /* -ENOENT, logic error */
8098                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8099                         ins->objectid, ins->offset);
8100                 BUG();
8101         }
8102         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
8103         return ret;
8104 }
8105
8106 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8107                                      struct btrfs_fs_info *fs_info,
8108                                      u64 parent, u64 root_objectid,
8109                                      u64 flags, struct btrfs_disk_key *key,
8110                                      int level, struct btrfs_key *ins)
8111 {
8112         int ret;
8113         struct btrfs_extent_item *extent_item;
8114         struct btrfs_tree_block_info *block_info;
8115         struct btrfs_extent_inline_ref *iref;
8116         struct btrfs_path *path;
8117         struct extent_buffer *leaf;
8118         u32 size = sizeof(*extent_item) + sizeof(*iref);
8119         u64 num_bytes = ins->offset;
8120         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8121
8122         if (!skinny_metadata)
8123                 size += sizeof(*block_info);
8124
8125         path = btrfs_alloc_path();
8126         if (!path) {
8127                 btrfs_free_and_pin_reserved_extent(fs_info, ins->objectid,
8128                                                    fs_info->nodesize);
8129                 return -ENOMEM;
8130         }
8131
8132         path->leave_spinning = 1;
8133         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8134                                       ins, size);
8135         if (ret) {
8136                 btrfs_free_path(path);
8137                 btrfs_free_and_pin_reserved_extent(fs_info, ins->objectid,
8138                                                    fs_info->nodesize);
8139                 return ret;
8140         }
8141
8142         leaf = path->nodes[0];
8143         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8144                                      struct btrfs_extent_item);
8145         btrfs_set_extent_refs(leaf, extent_item, 1);
8146         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8147         btrfs_set_extent_flags(leaf, extent_item,
8148                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8149
8150         if (skinny_metadata) {
8151                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8152                 num_bytes = fs_info->nodesize;
8153         } else {
8154                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8155                 btrfs_set_tree_block_key(leaf, block_info, key);
8156                 btrfs_set_tree_block_level(leaf, block_info, level);
8157                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8158         }
8159
8160         if (parent > 0) {
8161                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8162                 btrfs_set_extent_inline_ref_type(leaf, iref,
8163                                                  BTRFS_SHARED_BLOCK_REF_KEY);
8164                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8165         } else {
8166                 btrfs_set_extent_inline_ref_type(leaf, iref,
8167                                                  BTRFS_TREE_BLOCK_REF_KEY);
8168                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
8169         }
8170
8171         btrfs_mark_buffer_dirty(leaf);
8172         btrfs_free_path(path);
8173
8174         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8175                                           num_bytes);
8176         if (ret)
8177                 return ret;
8178
8179         ret = update_block_group(trans, fs_info, ins->objectid,
8180                                  fs_info->nodesize, 1);
8181         if (ret) { /* -ENOENT, logic error */
8182                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8183                         ins->objectid, ins->offset);
8184                 BUG();
8185         }
8186
8187         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid,
8188                                           fs_info->nodesize);
8189         return ret;
8190 }
8191
8192 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8193                                      u64 root_objectid, u64 owner,
8194                                      u64 offset, u64 ram_bytes,
8195                                      struct btrfs_key *ins)
8196 {
8197         struct btrfs_fs_info *fs_info = trans->fs_info;
8198         int ret;
8199
8200         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
8201
8202         ret = btrfs_add_delayed_data_ref(fs_info, trans, ins->objectid,
8203                                          ins->offset, 0,
8204                                          root_objectid, owner, offset,
8205                                          ram_bytes, BTRFS_ADD_DELAYED_EXTENT);
8206         return ret;
8207 }
8208
8209 /*
8210  * this is used by the tree logging recovery code.  It records that
8211  * an extent has been allocated and makes sure to clear the free
8212  * space cache bits as well
8213  */
8214 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8215                                    struct btrfs_fs_info *fs_info,
8216                                    u64 root_objectid, u64 owner, u64 offset,
8217                                    struct btrfs_key *ins)
8218 {
8219         int ret;
8220         struct btrfs_block_group_cache *block_group;
8221         struct btrfs_space_info *space_info;
8222
8223         /*
8224          * Mixed block groups will exclude before processing the log so we only
8225          * need to do the exclude dance if this fs isn't mixed.
8226          */
8227         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
8228                 ret = __exclude_logged_extent(fs_info, ins->objectid,
8229                                               ins->offset);
8230                 if (ret)
8231                         return ret;
8232         }
8233
8234         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
8235         if (!block_group)
8236                 return -EINVAL;
8237
8238         space_info = block_group->space_info;
8239         spin_lock(&space_info->lock);
8240         spin_lock(&block_group->lock);
8241         space_info->bytes_reserved += ins->offset;
8242         block_group->reserved += ins->offset;
8243         spin_unlock(&block_group->lock);
8244         spin_unlock(&space_info->lock);
8245
8246         ret = alloc_reserved_file_extent(trans, fs_info, 0, root_objectid,
8247                                          0, owner, offset, ins, 1);
8248         btrfs_put_block_group(block_group);
8249         return ret;
8250 }
8251
8252 static struct extent_buffer *
8253 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8254                       u64 bytenr, int level)
8255 {
8256         struct btrfs_fs_info *fs_info = root->fs_info;
8257         struct extent_buffer *buf;
8258
8259         buf = btrfs_find_create_tree_block(fs_info, bytenr);
8260         if (IS_ERR(buf))
8261                 return buf;
8262
8263         btrfs_set_header_generation(buf, trans->transid);
8264         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8265         btrfs_tree_lock(buf);
8266         clean_tree_block(fs_info, buf);
8267         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8268
8269         btrfs_set_lock_blocking(buf);
8270         set_extent_buffer_uptodate(buf);
8271
8272         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8273                 buf->log_index = root->log_transid % 2;
8274                 /*
8275                  * we allow two log transactions at a time, use different
8276                  * EXENT bit to differentiate dirty pages.
8277                  */
8278                 if (buf->log_index == 0)
8279                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8280                                         buf->start + buf->len - 1, GFP_NOFS);
8281                 else
8282                         set_extent_new(&root->dirty_log_pages, buf->start,
8283                                         buf->start + buf->len - 1);
8284         } else {
8285                 buf->log_index = -1;
8286                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8287                          buf->start + buf->len - 1, GFP_NOFS);
8288         }
8289         trans->dirty = true;
8290         /* this returns a buffer locked for blocking */
8291         return buf;
8292 }
8293
8294 static struct btrfs_block_rsv *
8295 use_block_rsv(struct btrfs_trans_handle *trans,
8296               struct btrfs_root *root, u32 blocksize)
8297 {
8298         struct btrfs_fs_info *fs_info = root->fs_info;
8299         struct btrfs_block_rsv *block_rsv;
8300         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
8301         int ret;
8302         bool global_updated = false;
8303
8304         block_rsv = get_block_rsv(trans, root);
8305
8306         if (unlikely(block_rsv->size == 0))
8307                 goto try_reserve;
8308 again:
8309         ret = block_rsv_use_bytes(block_rsv, blocksize);
8310         if (!ret)
8311                 return block_rsv;
8312
8313         if (block_rsv->failfast)
8314                 return ERR_PTR(ret);
8315
8316         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8317                 global_updated = true;
8318                 update_global_block_rsv(fs_info);
8319                 goto again;
8320         }
8321
8322         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8323                 static DEFINE_RATELIMIT_STATE(_rs,
8324                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8325                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8326                 if (__ratelimit(&_rs))
8327                         WARN(1, KERN_DEBUG
8328                                 "BTRFS: block rsv returned %d\n", ret);
8329         }
8330 try_reserve:
8331         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8332                                      BTRFS_RESERVE_NO_FLUSH);
8333         if (!ret)
8334                 return block_rsv;
8335         /*
8336          * If we couldn't reserve metadata bytes try and use some from
8337          * the global reserve if its space type is the same as the global
8338          * reservation.
8339          */
8340         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8341             block_rsv->space_info == global_rsv->space_info) {
8342                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8343                 if (!ret)
8344                         return global_rsv;
8345         }
8346         return ERR_PTR(ret);
8347 }
8348
8349 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8350                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8351 {
8352         block_rsv_add_bytes(block_rsv, blocksize, 0);
8353         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8354 }
8355
8356 /*
8357  * finds a free extent and does all the dirty work required for allocation
8358  * returns the tree buffer or an ERR_PTR on error.
8359  */
8360 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8361                                              struct btrfs_root *root,
8362                                              u64 parent, u64 root_objectid,
8363                                              const struct btrfs_disk_key *key,
8364                                              int level, u64 hint,
8365                                              u64 empty_size)
8366 {
8367         struct btrfs_fs_info *fs_info = root->fs_info;
8368         struct btrfs_key ins;
8369         struct btrfs_block_rsv *block_rsv;
8370         struct extent_buffer *buf;
8371         struct btrfs_delayed_extent_op *extent_op;
8372         u64 flags = 0;
8373         int ret;
8374         u32 blocksize = fs_info->nodesize;
8375         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8376
8377 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8378         if (btrfs_is_testing(fs_info)) {
8379                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8380                                             level);
8381                 if (!IS_ERR(buf))
8382                         root->alloc_bytenr += blocksize;
8383                 return buf;
8384         }
8385 #endif
8386
8387         block_rsv = use_block_rsv(trans, root, blocksize);
8388         if (IS_ERR(block_rsv))
8389                 return ERR_CAST(block_rsv);
8390
8391         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8392                                    empty_size, hint, &ins, 0, 0);
8393         if (ret)
8394                 goto out_unuse;
8395
8396         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8397         if (IS_ERR(buf)) {
8398                 ret = PTR_ERR(buf);
8399                 goto out_free_reserved;
8400         }
8401
8402         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8403                 if (parent == 0)
8404                         parent = ins.objectid;
8405                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8406         } else
8407                 BUG_ON(parent > 0);
8408
8409         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8410                 extent_op = btrfs_alloc_delayed_extent_op();
8411                 if (!extent_op) {
8412                         ret = -ENOMEM;
8413                         goto out_free_buf;
8414                 }
8415                 if (key)
8416                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8417                 else
8418                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8419                 extent_op->flags_to_set = flags;
8420                 extent_op->update_key = skinny_metadata ? false : true;
8421                 extent_op->update_flags = true;
8422                 extent_op->is_data = false;
8423                 extent_op->level = level;
8424
8425                 ret = btrfs_add_delayed_tree_ref(fs_info, trans,
8426                                                  ins.objectid, ins.offset,
8427                                                  parent, root_objectid, level,
8428                                                  BTRFS_ADD_DELAYED_EXTENT,
8429                                                  extent_op);
8430                 if (ret)
8431                         goto out_free_delayed;
8432         }
8433         return buf;
8434
8435 out_free_delayed:
8436         btrfs_free_delayed_extent_op(extent_op);
8437 out_free_buf:
8438         free_extent_buffer(buf);
8439 out_free_reserved:
8440         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
8441 out_unuse:
8442         unuse_block_rsv(fs_info, block_rsv, blocksize);
8443         return ERR_PTR(ret);
8444 }
8445
8446 struct walk_control {
8447         u64 refs[BTRFS_MAX_LEVEL];
8448         u64 flags[BTRFS_MAX_LEVEL];
8449         struct btrfs_key update_progress;
8450         int stage;
8451         int level;
8452         int shared_level;
8453         int update_ref;
8454         int keep_locks;
8455         int reada_slot;
8456         int reada_count;
8457         int for_reloc;
8458 };
8459
8460 #define DROP_REFERENCE  1
8461 #define UPDATE_BACKREF  2
8462
8463 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8464                                      struct btrfs_root *root,
8465                                      struct walk_control *wc,
8466                                      struct btrfs_path *path)
8467 {
8468         struct btrfs_fs_info *fs_info = root->fs_info;
8469         u64 bytenr;
8470         u64 generation;
8471         u64 refs;
8472         u64 flags;
8473         u32 nritems;
8474         struct btrfs_key key;
8475         struct extent_buffer *eb;
8476         int ret;
8477         int slot;
8478         int nread = 0;
8479
8480         if (path->slots[wc->level] < wc->reada_slot) {
8481                 wc->reada_count = wc->reada_count * 2 / 3;
8482                 wc->reada_count = max(wc->reada_count, 2);
8483         } else {
8484                 wc->reada_count = wc->reada_count * 3 / 2;
8485                 wc->reada_count = min_t(int, wc->reada_count,
8486                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
8487         }
8488
8489         eb = path->nodes[wc->level];
8490         nritems = btrfs_header_nritems(eb);
8491
8492         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8493                 if (nread >= wc->reada_count)
8494                         break;
8495
8496                 cond_resched();
8497                 bytenr = btrfs_node_blockptr(eb, slot);
8498                 generation = btrfs_node_ptr_generation(eb, slot);
8499
8500                 if (slot == path->slots[wc->level])
8501                         goto reada;
8502
8503                 if (wc->stage == UPDATE_BACKREF &&
8504                     generation <= root->root_key.offset)
8505                         continue;
8506
8507                 /* We don't lock the tree block, it's OK to be racy here */
8508                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
8509                                                wc->level - 1, 1, &refs,
8510                                                &flags);
8511                 /* We don't care about errors in readahead. */
8512                 if (ret < 0)
8513                         continue;
8514                 BUG_ON(refs == 0);
8515
8516                 if (wc->stage == DROP_REFERENCE) {
8517                         if (refs == 1)
8518                                 goto reada;
8519
8520                         if (wc->level == 1 &&
8521                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8522                                 continue;
8523                         if (!wc->update_ref ||
8524                             generation <= root->root_key.offset)
8525                                 continue;
8526                         btrfs_node_key_to_cpu(eb, &key, slot);
8527                         ret = btrfs_comp_cpu_keys(&key,
8528                                                   &wc->update_progress);
8529                         if (ret < 0)
8530                                 continue;
8531                 } else {
8532                         if (wc->level == 1 &&
8533                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8534                                 continue;
8535                 }
8536 reada:
8537                 readahead_tree_block(fs_info, bytenr);
8538                 nread++;
8539         }
8540         wc->reada_slot = slot;
8541 }
8542
8543 /*
8544  * helper to process tree block while walking down the tree.
8545  *
8546  * when wc->stage == UPDATE_BACKREF, this function updates
8547  * back refs for pointers in the block.
8548  *
8549  * NOTE: return value 1 means we should stop walking down.
8550  */
8551 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8552                                    struct btrfs_root *root,
8553                                    struct btrfs_path *path,
8554                                    struct walk_control *wc, int lookup_info)
8555 {
8556         struct btrfs_fs_info *fs_info = root->fs_info;
8557         int level = wc->level;
8558         struct extent_buffer *eb = path->nodes[level];
8559         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8560         int ret;
8561
8562         if (wc->stage == UPDATE_BACKREF &&
8563             btrfs_header_owner(eb) != root->root_key.objectid)
8564                 return 1;
8565
8566         /*
8567          * when reference count of tree block is 1, it won't increase
8568          * again. once full backref flag is set, we never clear it.
8569          */
8570         if (lookup_info &&
8571             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8572              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8573                 BUG_ON(!path->locks[level]);
8574                 ret = btrfs_lookup_extent_info(trans, fs_info,
8575                                                eb->start, level, 1,
8576                                                &wc->refs[level],
8577                                                &wc->flags[level]);
8578                 BUG_ON(ret == -ENOMEM);
8579                 if (ret)
8580                         return ret;
8581                 BUG_ON(wc->refs[level] == 0);
8582         }
8583
8584         if (wc->stage == DROP_REFERENCE) {
8585                 if (wc->refs[level] > 1)
8586                         return 1;
8587
8588                 if (path->locks[level] && !wc->keep_locks) {
8589                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8590                         path->locks[level] = 0;
8591                 }
8592                 return 0;
8593         }
8594
8595         /* wc->stage == UPDATE_BACKREF */
8596         if (!(wc->flags[level] & flag)) {
8597                 BUG_ON(!path->locks[level]);
8598                 ret = btrfs_inc_ref(trans, root, eb, 1);
8599                 BUG_ON(ret); /* -ENOMEM */
8600                 ret = btrfs_dec_ref(trans, root, eb, 0);
8601                 BUG_ON(ret); /* -ENOMEM */
8602                 ret = btrfs_set_disk_extent_flags(trans, fs_info, eb->start,
8603                                                   eb->len, flag,
8604                                                   btrfs_header_level(eb), 0);
8605                 BUG_ON(ret); /* -ENOMEM */
8606                 wc->flags[level] |= flag;
8607         }
8608
8609         /*
8610          * the block is shared by multiple trees, so it's not good to
8611          * keep the tree lock
8612          */
8613         if (path->locks[level] && level > 0) {
8614                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8615                 path->locks[level] = 0;
8616         }
8617         return 0;
8618 }
8619
8620 /*
8621  * helper to process tree block pointer.
8622  *
8623  * when wc->stage == DROP_REFERENCE, this function checks
8624  * reference count of the block pointed to. if the block
8625  * is shared and we need update back refs for the subtree
8626  * rooted at the block, this function changes wc->stage to
8627  * UPDATE_BACKREF. if the block is shared and there is no
8628  * need to update back, this function drops the reference
8629  * to the block.
8630  *
8631  * NOTE: return value 1 means we should stop walking down.
8632  */
8633 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8634                                  struct btrfs_root *root,
8635                                  struct btrfs_path *path,
8636                                  struct walk_control *wc, int *lookup_info)
8637 {
8638         struct btrfs_fs_info *fs_info = root->fs_info;
8639         u64 bytenr;
8640         u64 generation;
8641         u64 parent;
8642         u32 blocksize;
8643         struct btrfs_key key;
8644         struct extent_buffer *next;
8645         int level = wc->level;
8646         int reada = 0;
8647         int ret = 0;
8648         bool need_account = false;
8649
8650         generation = btrfs_node_ptr_generation(path->nodes[level],
8651                                                path->slots[level]);
8652         /*
8653          * if the lower level block was created before the snapshot
8654          * was created, we know there is no need to update back refs
8655          * for the subtree
8656          */
8657         if (wc->stage == UPDATE_BACKREF &&
8658             generation <= root->root_key.offset) {
8659                 *lookup_info = 1;
8660                 return 1;
8661         }
8662
8663         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8664         blocksize = fs_info->nodesize;
8665
8666         next = find_extent_buffer(fs_info, bytenr);
8667         if (!next) {
8668                 next = btrfs_find_create_tree_block(fs_info, bytenr);
8669                 if (IS_ERR(next))
8670                         return PTR_ERR(next);
8671
8672                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8673                                                level - 1);
8674                 reada = 1;
8675         }
8676         btrfs_tree_lock(next);
8677         btrfs_set_lock_blocking(next);
8678
8679         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
8680                                        &wc->refs[level - 1],
8681                                        &wc->flags[level - 1]);
8682         if (ret < 0)
8683                 goto out_unlock;
8684
8685         if (unlikely(wc->refs[level - 1] == 0)) {
8686                 btrfs_err(fs_info, "Missing references.");
8687                 ret = -EIO;
8688                 goto out_unlock;
8689         }
8690         *lookup_info = 0;
8691
8692         if (wc->stage == DROP_REFERENCE) {
8693                 if (wc->refs[level - 1] > 1) {
8694                         need_account = true;
8695                         if (level == 1 &&
8696                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8697                                 goto skip;
8698
8699                         if (!wc->update_ref ||
8700                             generation <= root->root_key.offset)
8701                                 goto skip;
8702
8703                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8704                                               path->slots[level]);
8705                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8706                         if (ret < 0)
8707                                 goto skip;
8708
8709                         wc->stage = UPDATE_BACKREF;
8710                         wc->shared_level = level - 1;
8711                 }
8712         } else {
8713                 if (level == 1 &&
8714                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8715                         goto skip;
8716         }
8717
8718         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8719                 btrfs_tree_unlock(next);
8720                 free_extent_buffer(next);
8721                 next = NULL;
8722                 *lookup_info = 1;
8723         }
8724
8725         if (!next) {
8726                 if (reada && level == 1)
8727                         reada_walk_down(trans, root, wc, path);
8728                 next = read_tree_block(fs_info, bytenr, generation);
8729                 if (IS_ERR(next)) {
8730                         return PTR_ERR(next);
8731                 } else if (!extent_buffer_uptodate(next)) {
8732                         free_extent_buffer(next);
8733                         return -EIO;
8734                 }
8735                 btrfs_tree_lock(next);
8736                 btrfs_set_lock_blocking(next);
8737         }
8738
8739         level--;
8740         ASSERT(level == btrfs_header_level(next));
8741         if (level != btrfs_header_level(next)) {
8742                 btrfs_err(root->fs_info, "mismatched level");
8743                 ret = -EIO;
8744                 goto out_unlock;
8745         }
8746         path->nodes[level] = next;
8747         path->slots[level] = 0;
8748         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8749         wc->level = level;
8750         if (wc->level == 1)
8751                 wc->reada_slot = 0;
8752         return 0;
8753 skip:
8754         wc->refs[level - 1] = 0;
8755         wc->flags[level - 1] = 0;
8756         if (wc->stage == DROP_REFERENCE) {
8757                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8758                         parent = path->nodes[level]->start;
8759                 } else {
8760                         ASSERT(root->root_key.objectid ==
8761                                btrfs_header_owner(path->nodes[level]));
8762                         if (root->root_key.objectid !=
8763                             btrfs_header_owner(path->nodes[level])) {
8764                                 btrfs_err(root->fs_info,
8765                                                 "mismatched block owner");
8766                                 ret = -EIO;
8767                                 goto out_unlock;
8768                         }
8769                         parent = 0;
8770                 }
8771
8772                 if (need_account) {
8773                         ret = btrfs_qgroup_trace_subtree(trans, root, next,
8774                                                          generation, level - 1);
8775                         if (ret) {
8776                                 btrfs_err_rl(fs_info,
8777                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8778                                              ret);
8779                         }
8780                 }
8781                 ret = btrfs_free_extent(trans, fs_info, bytenr, blocksize,
8782                                         parent, root->root_key.objectid,
8783                                         level - 1, 0);
8784                 if (ret)
8785                         goto out_unlock;
8786         }
8787
8788         *lookup_info = 1;
8789         ret = 1;
8790
8791 out_unlock:
8792         btrfs_tree_unlock(next);
8793         free_extent_buffer(next);
8794
8795         return ret;
8796 }
8797
8798 /*
8799  * helper to process tree block while walking up the tree.
8800  *
8801  * when wc->stage == DROP_REFERENCE, this function drops
8802  * reference count on the block.
8803  *
8804  * when wc->stage == UPDATE_BACKREF, this function changes
8805  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8806  * to UPDATE_BACKREF previously while processing the block.
8807  *
8808  * NOTE: return value 1 means we should stop walking up.
8809  */
8810 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8811                                  struct btrfs_root *root,
8812                                  struct btrfs_path *path,
8813                                  struct walk_control *wc)
8814 {
8815         struct btrfs_fs_info *fs_info = root->fs_info;
8816         int ret;
8817         int level = wc->level;
8818         struct extent_buffer *eb = path->nodes[level];
8819         u64 parent = 0;
8820
8821         if (wc->stage == UPDATE_BACKREF) {
8822                 BUG_ON(wc->shared_level < level);
8823                 if (level < wc->shared_level)
8824                         goto out;
8825
8826                 ret = find_next_key(path, level + 1, &wc->update_progress);
8827                 if (ret > 0)
8828                         wc->update_ref = 0;
8829
8830                 wc->stage = DROP_REFERENCE;
8831                 wc->shared_level = -1;
8832                 path->slots[level] = 0;
8833
8834                 /*
8835                  * check reference count again if the block isn't locked.
8836                  * we should start walking down the tree again if reference
8837                  * count is one.
8838                  */
8839                 if (!path->locks[level]) {
8840                         BUG_ON(level == 0);
8841                         btrfs_tree_lock(eb);
8842                         btrfs_set_lock_blocking(eb);
8843                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8844
8845                         ret = btrfs_lookup_extent_info(trans, fs_info,
8846                                                        eb->start, level, 1,
8847                                                        &wc->refs[level],
8848                                                        &wc->flags[level]);
8849                         if (ret < 0) {
8850                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8851                                 path->locks[level] = 0;
8852                                 return ret;
8853                         }
8854                         BUG_ON(wc->refs[level] == 0);
8855                         if (wc->refs[level] == 1) {
8856                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8857                                 path->locks[level] = 0;
8858                                 return 1;
8859                         }
8860                 }
8861         }
8862
8863         /* wc->stage == DROP_REFERENCE */
8864         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8865
8866         if (wc->refs[level] == 1) {
8867                 if (level == 0) {
8868                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8869                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8870                         else
8871                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8872                         BUG_ON(ret); /* -ENOMEM */
8873                         ret = btrfs_qgroup_trace_leaf_items(trans, fs_info, eb);
8874                         if (ret) {
8875                                 btrfs_err_rl(fs_info,
8876                                              "error %d accounting leaf items. Quota is out of sync, rescan required.",
8877                                              ret);
8878                         }
8879                 }
8880                 /* make block locked assertion in clean_tree_block happy */
8881                 if (!path->locks[level] &&
8882                     btrfs_header_generation(eb) == trans->transid) {
8883                         btrfs_tree_lock(eb);
8884                         btrfs_set_lock_blocking(eb);
8885                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8886                 }
8887                 clean_tree_block(fs_info, eb);
8888         }
8889
8890         if (eb == root->node) {
8891                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8892                         parent = eb->start;
8893                 else
8894                         BUG_ON(root->root_key.objectid !=
8895                                btrfs_header_owner(eb));
8896         } else {
8897                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8898                         parent = path->nodes[level + 1]->start;
8899                 else
8900                         BUG_ON(root->root_key.objectid !=
8901                                btrfs_header_owner(path->nodes[level + 1]));
8902         }
8903
8904         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8905 out:
8906         wc->refs[level] = 0;
8907         wc->flags[level] = 0;
8908         return 0;
8909 }
8910
8911 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8912                                    struct btrfs_root *root,
8913                                    struct btrfs_path *path,
8914                                    struct walk_control *wc)
8915 {
8916         int level = wc->level;
8917         int lookup_info = 1;
8918         int ret;
8919
8920         while (level >= 0) {
8921                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8922                 if (ret > 0)
8923                         break;
8924
8925                 if (level == 0)
8926                         break;
8927
8928                 if (path->slots[level] >=
8929                     btrfs_header_nritems(path->nodes[level]))
8930                         break;
8931
8932                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8933                 if (ret > 0) {
8934                         path->slots[level]++;
8935                         continue;
8936                 } else if (ret < 0)
8937                         return ret;
8938                 level = wc->level;
8939         }
8940         return 0;
8941 }
8942
8943 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8944                                  struct btrfs_root *root,
8945                                  struct btrfs_path *path,
8946                                  struct walk_control *wc, int max_level)
8947 {
8948         int level = wc->level;
8949         int ret;
8950
8951         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8952         while (level < max_level && path->nodes[level]) {
8953                 wc->level = level;
8954                 if (path->slots[level] + 1 <
8955                     btrfs_header_nritems(path->nodes[level])) {
8956                         path->slots[level]++;
8957                         return 0;
8958                 } else {
8959                         ret = walk_up_proc(trans, root, path, wc);
8960                         if (ret > 0)
8961                                 return 0;
8962
8963                         if (path->locks[level]) {
8964                                 btrfs_tree_unlock_rw(path->nodes[level],
8965                                                      path->locks[level]);
8966                                 path->locks[level] = 0;
8967                         }
8968                         free_extent_buffer(path->nodes[level]);
8969                         path->nodes[level] = NULL;
8970                         level++;
8971                 }
8972         }
8973         return 1;
8974 }
8975
8976 /*
8977  * drop a subvolume tree.
8978  *
8979  * this function traverses the tree freeing any blocks that only
8980  * referenced by the tree.
8981  *
8982  * when a shared tree block is found. this function decreases its
8983  * reference count by one. if update_ref is true, this function
8984  * also make sure backrefs for the shared block and all lower level
8985  * blocks are properly updated.
8986  *
8987  * If called with for_reloc == 0, may exit early with -EAGAIN
8988  */
8989 int btrfs_drop_snapshot(struct btrfs_root *root,
8990                          struct btrfs_block_rsv *block_rsv, int update_ref,
8991                          int for_reloc)
8992 {
8993         struct btrfs_fs_info *fs_info = root->fs_info;
8994         struct btrfs_path *path;
8995         struct btrfs_trans_handle *trans;
8996         struct btrfs_root *tree_root = fs_info->tree_root;
8997         struct btrfs_root_item *root_item = &root->root_item;
8998         struct walk_control *wc;
8999         struct btrfs_key key;
9000         int err = 0;
9001         int ret;
9002         int level;
9003         bool root_dropped = false;
9004
9005         btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
9006
9007         path = btrfs_alloc_path();
9008         if (!path) {
9009                 err = -ENOMEM;
9010                 goto out;
9011         }
9012
9013         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9014         if (!wc) {
9015                 btrfs_free_path(path);
9016                 err = -ENOMEM;
9017                 goto out;
9018         }
9019
9020         trans = btrfs_start_transaction(tree_root, 0);
9021         if (IS_ERR(trans)) {
9022                 err = PTR_ERR(trans);
9023                 goto out_free;
9024         }
9025
9026         if (block_rsv)
9027                 trans->block_rsv = block_rsv;
9028
9029         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9030                 level = btrfs_header_level(root->node);
9031                 path->nodes[level] = btrfs_lock_root_node(root);
9032                 btrfs_set_lock_blocking(path->nodes[level]);
9033                 path->slots[level] = 0;
9034                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9035                 memset(&wc->update_progress, 0,
9036                        sizeof(wc->update_progress));
9037         } else {
9038                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9039                 memcpy(&wc->update_progress, &key,
9040                        sizeof(wc->update_progress));
9041
9042                 level = root_item->drop_level;
9043                 BUG_ON(level == 0);
9044                 path->lowest_level = level;
9045                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9046                 path->lowest_level = 0;
9047                 if (ret < 0) {
9048                         err = ret;
9049                         goto out_end_trans;
9050                 }
9051                 WARN_ON(ret > 0);
9052
9053                 /*
9054                  * unlock our path, this is safe because only this
9055                  * function is allowed to delete this snapshot
9056                  */
9057                 btrfs_unlock_up_safe(path, 0);
9058
9059                 level = btrfs_header_level(root->node);
9060                 while (1) {
9061                         btrfs_tree_lock(path->nodes[level]);
9062                         btrfs_set_lock_blocking(path->nodes[level]);
9063                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9064
9065                         ret = btrfs_lookup_extent_info(trans, fs_info,
9066                                                 path->nodes[level]->start,
9067                                                 level, 1, &wc->refs[level],
9068                                                 &wc->flags[level]);
9069                         if (ret < 0) {
9070                                 err = ret;
9071                                 goto out_end_trans;
9072                         }
9073                         BUG_ON(wc->refs[level] == 0);
9074
9075                         if (level == root_item->drop_level)
9076                                 break;
9077
9078                         btrfs_tree_unlock(path->nodes[level]);
9079                         path->locks[level] = 0;
9080                         WARN_ON(wc->refs[level] != 1);
9081                         level--;
9082                 }
9083         }
9084
9085         wc->level = level;
9086         wc->shared_level = -1;
9087         wc->stage = DROP_REFERENCE;
9088         wc->update_ref = update_ref;
9089         wc->keep_locks = 0;
9090         wc->for_reloc = for_reloc;
9091         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9092
9093         while (1) {
9094
9095                 ret = walk_down_tree(trans, root, path, wc);
9096                 if (ret < 0) {
9097                         err = ret;
9098                         break;
9099                 }
9100
9101                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9102                 if (ret < 0) {
9103                         err = ret;
9104                         break;
9105                 }
9106
9107                 if (ret > 0) {
9108                         BUG_ON(wc->stage != DROP_REFERENCE);
9109                         break;
9110                 }
9111
9112                 if (wc->stage == DROP_REFERENCE) {
9113                         level = wc->level;
9114                         btrfs_node_key(path->nodes[level],
9115                                        &root_item->drop_progress,
9116                                        path->slots[level]);
9117                         root_item->drop_level = level;
9118                 }
9119
9120                 BUG_ON(wc->level == 0);
9121                 if (btrfs_should_end_transaction(trans) ||
9122                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
9123                         ret = btrfs_update_root(trans, tree_root,
9124                                                 &root->root_key,
9125                                                 root_item);
9126                         if (ret) {
9127                                 btrfs_abort_transaction(trans, ret);
9128                                 err = ret;
9129                                 goto out_end_trans;
9130                         }
9131
9132                         btrfs_end_transaction_throttle(trans);
9133                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
9134                                 btrfs_debug(fs_info,
9135                                             "drop snapshot early exit");
9136                                 err = -EAGAIN;
9137                                 goto out_free;
9138                         }
9139
9140                         trans = btrfs_start_transaction(tree_root, 0);
9141                         if (IS_ERR(trans)) {
9142                                 err = PTR_ERR(trans);
9143                                 goto out_free;
9144                         }
9145                         if (block_rsv)
9146                                 trans->block_rsv = block_rsv;
9147                 }
9148         }
9149         btrfs_release_path(path);
9150         if (err)
9151                 goto out_end_trans;
9152
9153         ret = btrfs_del_root(trans, tree_root, &root->root_key);
9154         if (ret) {
9155                 btrfs_abort_transaction(trans, ret);
9156                 goto out_end_trans;
9157         }
9158
9159         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9160                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9161                                       NULL, NULL);
9162                 if (ret < 0) {
9163                         btrfs_abort_transaction(trans, ret);
9164                         err = ret;
9165                         goto out_end_trans;
9166                 } else if (ret > 0) {
9167                         /* if we fail to delete the orphan item this time
9168                          * around, it'll get picked up the next time.
9169                          *
9170                          * The most common failure here is just -ENOENT.
9171                          */
9172                         btrfs_del_orphan_item(trans, tree_root,
9173                                               root->root_key.objectid);
9174                 }
9175         }
9176
9177         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9178                 btrfs_add_dropped_root(trans, root);
9179         } else {
9180                 free_extent_buffer(root->node);
9181                 free_extent_buffer(root->commit_root);
9182                 btrfs_put_fs_root(root);
9183         }
9184         root_dropped = true;
9185 out_end_trans:
9186         btrfs_end_transaction_throttle(trans);
9187 out_free:
9188         kfree(wc);
9189         btrfs_free_path(path);
9190 out:
9191         /*
9192          * So if we need to stop dropping the snapshot for whatever reason we
9193          * need to make sure to add it back to the dead root list so that we
9194          * keep trying to do the work later.  This also cleans up roots if we
9195          * don't have it in the radix (like when we recover after a power fail
9196          * or unmount) so we don't leak memory.
9197          */
9198         if (!for_reloc && root_dropped == false)
9199                 btrfs_add_dead_root(root);
9200         if (err && err != -EAGAIN)
9201                 btrfs_handle_fs_error(fs_info, err, NULL);
9202         return err;
9203 }
9204
9205 /*
9206  * drop subtree rooted at tree block 'node'.
9207  *
9208  * NOTE: this function will unlock and release tree block 'node'
9209  * only used by relocation code
9210  */
9211 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9212                         struct btrfs_root *root,
9213                         struct extent_buffer *node,
9214                         struct extent_buffer *parent)
9215 {
9216         struct btrfs_fs_info *fs_info = root->fs_info;
9217         struct btrfs_path *path;
9218         struct walk_control *wc;
9219         int level;
9220         int parent_level;
9221         int ret = 0;
9222         int wret;
9223
9224         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9225
9226         path = btrfs_alloc_path();
9227         if (!path)
9228                 return -ENOMEM;
9229
9230         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9231         if (!wc) {
9232                 btrfs_free_path(path);
9233                 return -ENOMEM;
9234         }
9235
9236         btrfs_assert_tree_locked(parent);
9237         parent_level = btrfs_header_level(parent);
9238         extent_buffer_get(parent);
9239         path->nodes[parent_level] = parent;
9240         path->slots[parent_level] = btrfs_header_nritems(parent);
9241
9242         btrfs_assert_tree_locked(node);
9243         level = btrfs_header_level(node);
9244         path->nodes[level] = node;
9245         path->slots[level] = 0;
9246         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9247
9248         wc->refs[parent_level] = 1;
9249         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9250         wc->level = level;
9251         wc->shared_level = -1;
9252         wc->stage = DROP_REFERENCE;
9253         wc->update_ref = 0;
9254         wc->keep_locks = 1;
9255         wc->for_reloc = 1;
9256         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9257
9258         while (1) {
9259                 wret = walk_down_tree(trans, root, path, wc);
9260                 if (wret < 0) {
9261                         ret = wret;
9262                         break;
9263                 }
9264
9265                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9266                 if (wret < 0)
9267                         ret = wret;
9268                 if (wret != 0)
9269                         break;
9270         }
9271
9272         kfree(wc);
9273         btrfs_free_path(path);
9274         return ret;
9275 }
9276
9277 static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
9278 {
9279         u64 num_devices;
9280         u64 stripped;
9281
9282         /*
9283          * if restripe for this chunk_type is on pick target profile and
9284          * return, otherwise do the usual balance
9285          */
9286         stripped = get_restripe_target(fs_info, flags);
9287         if (stripped)
9288                 return extended_to_chunk(stripped);
9289
9290         num_devices = fs_info->fs_devices->rw_devices;
9291
9292         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9293                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9294                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9295
9296         if (num_devices == 1) {
9297                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9298                 stripped = flags & ~stripped;
9299
9300                 /* turn raid0 into single device chunks */
9301                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9302                         return stripped;
9303
9304                 /* turn mirroring into duplication */
9305                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9306                              BTRFS_BLOCK_GROUP_RAID10))
9307                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9308         } else {
9309                 /* they already had raid on here, just return */
9310                 if (flags & stripped)
9311                         return flags;
9312
9313                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9314                 stripped = flags & ~stripped;
9315
9316                 /* switch duplicated blocks with raid1 */
9317                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9318                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9319
9320                 /* this is drive concat, leave it alone */
9321         }
9322
9323         return flags;
9324 }
9325
9326 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9327 {
9328         struct btrfs_space_info *sinfo = cache->space_info;
9329         u64 num_bytes;
9330         u64 min_allocable_bytes;
9331         int ret = -ENOSPC;
9332
9333         /*
9334          * We need some metadata space and system metadata space for
9335          * allocating chunks in some corner cases until we force to set
9336          * it to be readonly.
9337          */
9338         if ((sinfo->flags &
9339              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9340             !force)
9341                 min_allocable_bytes = SZ_1M;
9342         else
9343                 min_allocable_bytes = 0;
9344
9345         spin_lock(&sinfo->lock);
9346         spin_lock(&cache->lock);
9347
9348         if (cache->ro) {
9349                 cache->ro++;
9350                 ret = 0;
9351                 goto out;
9352         }
9353
9354         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9355                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9356
9357         if (btrfs_space_info_used(sinfo, true) + num_bytes +
9358             min_allocable_bytes <= sinfo->total_bytes) {
9359                 sinfo->bytes_readonly += num_bytes;
9360                 cache->ro++;
9361                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9362                 ret = 0;
9363         }
9364 out:
9365         spin_unlock(&cache->lock);
9366         spin_unlock(&sinfo->lock);
9367         return ret;
9368 }
9369
9370 int btrfs_inc_block_group_ro(struct btrfs_fs_info *fs_info,
9371                              struct btrfs_block_group_cache *cache)
9372
9373 {
9374         struct btrfs_trans_handle *trans;
9375         u64 alloc_flags;
9376         int ret;
9377
9378 again:
9379         trans = btrfs_join_transaction(fs_info->extent_root);
9380         if (IS_ERR(trans))
9381                 return PTR_ERR(trans);
9382
9383         /*
9384          * we're not allowed to set block groups readonly after the dirty
9385          * block groups cache has started writing.  If it already started,
9386          * back off and let this transaction commit
9387          */
9388         mutex_lock(&fs_info->ro_block_group_mutex);
9389         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9390                 u64 transid = trans->transid;
9391
9392                 mutex_unlock(&fs_info->ro_block_group_mutex);
9393                 btrfs_end_transaction(trans);
9394
9395                 ret = btrfs_wait_for_commit(fs_info, transid);
9396                 if (ret)
9397                         return ret;
9398                 goto again;
9399         }
9400
9401         /*
9402          * if we are changing raid levels, try to allocate a corresponding
9403          * block group with the new raid level.
9404          */
9405         alloc_flags = update_block_group_flags(fs_info, cache->flags);
9406         if (alloc_flags != cache->flags) {
9407                 ret = do_chunk_alloc(trans, fs_info, alloc_flags,
9408                                      CHUNK_ALLOC_FORCE);
9409                 /*
9410                  * ENOSPC is allowed here, we may have enough space
9411                  * already allocated at the new raid level to
9412                  * carry on
9413                  */
9414                 if (ret == -ENOSPC)
9415                         ret = 0;
9416                 if (ret < 0)
9417                         goto out;
9418         }
9419
9420         ret = inc_block_group_ro(cache, 0);
9421         if (!ret)
9422                 goto out;
9423         alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
9424         ret = do_chunk_alloc(trans, fs_info, alloc_flags,
9425                              CHUNK_ALLOC_FORCE);
9426         if (ret < 0)
9427                 goto out;
9428         ret = inc_block_group_ro(cache, 0);
9429 out:
9430         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9431                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
9432                 mutex_lock(&fs_info->chunk_mutex);
9433                 check_system_chunk(trans, fs_info, alloc_flags);
9434                 mutex_unlock(&fs_info->chunk_mutex);
9435         }
9436         mutex_unlock(&fs_info->ro_block_group_mutex);
9437
9438         btrfs_end_transaction(trans);
9439         return ret;
9440 }
9441
9442 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9443                             struct btrfs_fs_info *fs_info, u64 type)
9444 {
9445         u64 alloc_flags = get_alloc_profile(fs_info, type);
9446
9447         return do_chunk_alloc(trans, fs_info, alloc_flags, CHUNK_ALLOC_FORCE);
9448 }
9449
9450 /*
9451  * helper to account the unused space of all the readonly block group in the
9452  * space_info. takes mirrors into account.
9453  */
9454 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9455 {
9456         struct btrfs_block_group_cache *block_group;
9457         u64 free_bytes = 0;
9458         int factor;
9459
9460         /* It's df, we don't care if it's racy */
9461         if (list_empty(&sinfo->ro_bgs))
9462                 return 0;
9463
9464         spin_lock(&sinfo->lock);
9465         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9466                 spin_lock(&block_group->lock);
9467
9468                 if (!block_group->ro) {
9469                         spin_unlock(&block_group->lock);
9470                         continue;
9471                 }
9472
9473                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9474                                           BTRFS_BLOCK_GROUP_RAID10 |
9475                                           BTRFS_BLOCK_GROUP_DUP))
9476                         factor = 2;
9477                 else
9478                         factor = 1;
9479
9480                 free_bytes += (block_group->key.offset -
9481                                btrfs_block_group_used(&block_group->item)) *
9482                                factor;
9483
9484                 spin_unlock(&block_group->lock);
9485         }
9486         spin_unlock(&sinfo->lock);
9487
9488         return free_bytes;
9489 }
9490
9491 void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
9492 {
9493         struct btrfs_space_info *sinfo = cache->space_info;
9494         u64 num_bytes;
9495
9496         BUG_ON(!cache->ro);
9497
9498         spin_lock(&sinfo->lock);
9499         spin_lock(&cache->lock);
9500         if (!--cache->ro) {
9501                 num_bytes = cache->key.offset - cache->reserved -
9502                             cache->pinned - cache->bytes_super -
9503                             btrfs_block_group_used(&cache->item);
9504                 sinfo->bytes_readonly -= num_bytes;
9505                 list_del_init(&cache->ro_list);
9506         }
9507         spin_unlock(&cache->lock);
9508         spin_unlock(&sinfo->lock);
9509 }
9510
9511 /*
9512  * checks to see if its even possible to relocate this block group.
9513  *
9514  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9515  * ok to go ahead and try.
9516  */
9517 int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)
9518 {
9519         struct btrfs_root *root = fs_info->extent_root;
9520         struct btrfs_block_group_cache *block_group;
9521         struct btrfs_space_info *space_info;
9522         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
9523         struct btrfs_device *device;
9524         struct btrfs_trans_handle *trans;
9525         u64 min_free;
9526         u64 dev_min = 1;
9527         u64 dev_nr = 0;
9528         u64 target;
9529         int debug;
9530         int index;
9531         int full = 0;
9532         int ret = 0;
9533
9534         debug = btrfs_test_opt(fs_info, ENOSPC_DEBUG);
9535
9536         block_group = btrfs_lookup_block_group(fs_info, bytenr);
9537
9538         /* odd, couldn't find the block group, leave it alone */
9539         if (!block_group) {
9540                 if (debug)
9541                         btrfs_warn(fs_info,
9542                                    "can't find block group for bytenr %llu",
9543                                    bytenr);
9544                 return -1;
9545         }
9546
9547         min_free = btrfs_block_group_used(&block_group->item);
9548
9549         /* no bytes used, we're good */
9550         if (!min_free)
9551                 goto out;
9552
9553         space_info = block_group->space_info;
9554         spin_lock(&space_info->lock);
9555
9556         full = space_info->full;
9557
9558         /*
9559          * if this is the last block group we have in this space, we can't
9560          * relocate it unless we're able to allocate a new chunk below.
9561          *
9562          * Otherwise, we need to make sure we have room in the space to handle
9563          * all of the extents from this block group.  If we can, we're good
9564          */
9565         if ((space_info->total_bytes != block_group->key.offset) &&
9566             (btrfs_space_info_used(space_info, false) + min_free <
9567              space_info->total_bytes)) {
9568                 spin_unlock(&space_info->lock);
9569                 goto out;
9570         }
9571         spin_unlock(&space_info->lock);
9572
9573         /*
9574          * ok we don't have enough space, but maybe we have free space on our
9575          * devices to allocate new chunks for relocation, so loop through our
9576          * alloc devices and guess if we have enough space.  if this block
9577          * group is going to be restriped, run checks against the target
9578          * profile instead of the current one.
9579          */
9580         ret = -1;
9581
9582         /*
9583          * index:
9584          *      0: raid10
9585          *      1: raid1
9586          *      2: dup
9587          *      3: raid0
9588          *      4: single
9589          */
9590         target = get_restripe_target(fs_info, block_group->flags);
9591         if (target) {
9592                 index = __get_raid_index(extended_to_chunk(target));
9593         } else {
9594                 /*
9595                  * this is just a balance, so if we were marked as full
9596                  * we know there is no space for a new chunk
9597                  */
9598                 if (full) {
9599                         if (debug)
9600                                 btrfs_warn(fs_info,
9601                                            "no space to alloc new chunk for block group %llu",
9602                                            block_group->key.objectid);
9603                         goto out;
9604                 }
9605
9606                 index = get_block_group_index(block_group);
9607         }
9608
9609         if (index == BTRFS_RAID_RAID10) {
9610                 dev_min = 4;
9611                 /* Divide by 2 */
9612                 min_free >>= 1;
9613         } else if (index == BTRFS_RAID_RAID1) {
9614                 dev_min = 2;
9615         } else if (index == BTRFS_RAID_DUP) {
9616                 /* Multiply by 2 */
9617                 min_free <<= 1;
9618         } else if (index == BTRFS_RAID_RAID0) {
9619                 dev_min = fs_devices->rw_devices;
9620                 min_free = div64_u64(min_free, dev_min);
9621         }
9622
9623         /* We need to do this so that we can look at pending chunks */
9624         trans = btrfs_join_transaction(root);
9625         if (IS_ERR(trans)) {
9626                 ret = PTR_ERR(trans);
9627                 goto out;
9628         }
9629
9630         mutex_lock(&fs_info->chunk_mutex);
9631         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9632                 u64 dev_offset;
9633
9634                 /*
9635                  * check to make sure we can actually find a chunk with enough
9636                  * space to fit our block group in.
9637                  */
9638                 if (device->total_bytes > device->bytes_used + min_free &&
9639                     !device->is_tgtdev_for_dev_replace) {
9640                         ret = find_free_dev_extent(trans, device, min_free,
9641                                                    &dev_offset, NULL);
9642                         if (!ret)
9643                                 dev_nr++;
9644
9645                         if (dev_nr >= dev_min)
9646                                 break;
9647
9648                         ret = -1;
9649                 }
9650         }
9651         if (debug && ret == -1)
9652                 btrfs_warn(fs_info,
9653                            "no space to allocate a new chunk for block group %llu",
9654                            block_group->key.objectid);
9655         mutex_unlock(&fs_info->chunk_mutex);
9656         btrfs_end_transaction(trans);
9657 out:
9658         btrfs_put_block_group(block_group);
9659         return ret;
9660 }
9661
9662 static int find_first_block_group(struct btrfs_fs_info *fs_info,
9663                                   struct btrfs_path *path,
9664                                   struct btrfs_key *key)
9665 {
9666         struct btrfs_root *root = fs_info->extent_root;
9667         int ret = 0;
9668         struct btrfs_key found_key;
9669         struct extent_buffer *leaf;
9670         int slot;
9671
9672         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9673         if (ret < 0)
9674                 goto out;
9675
9676         while (1) {
9677                 slot = path->slots[0];
9678                 leaf = path->nodes[0];
9679                 if (slot >= btrfs_header_nritems(leaf)) {
9680                         ret = btrfs_next_leaf(root, path);
9681                         if (ret == 0)
9682                                 continue;
9683                         if (ret < 0)
9684                                 goto out;
9685                         break;
9686                 }
9687                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9688
9689                 if (found_key.objectid >= key->objectid &&
9690                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9691                         struct extent_map_tree *em_tree;
9692                         struct extent_map *em;
9693
9694                         em_tree = &root->fs_info->mapping_tree.map_tree;
9695                         read_lock(&em_tree->lock);
9696                         em = lookup_extent_mapping(em_tree, found_key.objectid,
9697                                                    found_key.offset);
9698                         read_unlock(&em_tree->lock);
9699                         if (!em) {
9700                                 btrfs_err(fs_info,
9701                         "logical %llu len %llu found bg but no related chunk",
9702                                           found_key.objectid, found_key.offset);
9703                                 ret = -ENOENT;
9704                         } else {
9705                                 ret = 0;
9706                         }
9707                         free_extent_map(em);
9708                         goto out;
9709                 }
9710                 path->slots[0]++;
9711         }
9712 out:
9713         return ret;
9714 }
9715
9716 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9717 {
9718         struct btrfs_block_group_cache *block_group;
9719         u64 last = 0;
9720
9721         while (1) {
9722                 struct inode *inode;
9723
9724                 block_group = btrfs_lookup_first_block_group(info, last);
9725                 while (block_group) {
9726                         spin_lock(&block_group->lock);
9727                         if (block_group->iref)
9728                                 break;
9729                         spin_unlock(&block_group->lock);
9730                         block_group = next_block_group(info, block_group);
9731                 }
9732                 if (!block_group) {
9733                         if (last == 0)
9734                                 break;
9735                         last = 0;
9736                         continue;
9737                 }
9738
9739                 inode = block_group->inode;
9740                 block_group->iref = 0;
9741                 block_group->inode = NULL;
9742                 spin_unlock(&block_group->lock);
9743                 ASSERT(block_group->io_ctl.inode == NULL);
9744                 iput(inode);
9745                 last = block_group->key.objectid + block_group->key.offset;
9746                 btrfs_put_block_group(block_group);
9747         }
9748 }
9749
9750 /*
9751  * Must be called only after stopping all workers, since we could have block
9752  * group caching kthreads running, and therefore they could race with us if we
9753  * freed the block groups before stopping them.
9754  */
9755 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9756 {
9757         struct btrfs_block_group_cache *block_group;
9758         struct btrfs_space_info *space_info;
9759         struct btrfs_caching_control *caching_ctl;
9760         struct rb_node *n;
9761
9762         down_write(&info->commit_root_sem);
9763         while (!list_empty(&info->caching_block_groups)) {
9764                 caching_ctl = list_entry(info->caching_block_groups.next,
9765                                          struct btrfs_caching_control, list);
9766                 list_del(&caching_ctl->list);
9767                 put_caching_control(caching_ctl);
9768         }
9769         up_write(&info->commit_root_sem);
9770
9771         spin_lock(&info->unused_bgs_lock);
9772         while (!list_empty(&info->unused_bgs)) {
9773                 block_group = list_first_entry(&info->unused_bgs,
9774                                                struct btrfs_block_group_cache,
9775                                                bg_list);
9776                 list_del_init(&block_group->bg_list);
9777                 btrfs_put_block_group(block_group);
9778         }
9779         spin_unlock(&info->unused_bgs_lock);
9780
9781         spin_lock(&info->block_group_cache_lock);
9782         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9783                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9784                                        cache_node);
9785                 rb_erase(&block_group->cache_node,
9786                          &info->block_group_cache_tree);
9787                 RB_CLEAR_NODE(&block_group->cache_node);
9788                 spin_unlock(&info->block_group_cache_lock);
9789
9790                 down_write(&block_group->space_info->groups_sem);
9791                 list_del(&block_group->list);
9792                 up_write(&block_group->space_info->groups_sem);
9793
9794                 /*
9795                  * We haven't cached this block group, which means we could
9796                  * possibly have excluded extents on this block group.
9797                  */
9798                 if (block_group->cached == BTRFS_CACHE_NO ||
9799                     block_group->cached == BTRFS_CACHE_ERROR)
9800                         free_excluded_extents(info, block_group);
9801
9802                 btrfs_remove_free_space_cache(block_group);
9803                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
9804                 ASSERT(list_empty(&block_group->dirty_list));
9805                 ASSERT(list_empty(&block_group->io_list));
9806                 ASSERT(list_empty(&block_group->bg_list));
9807                 ASSERT(atomic_read(&block_group->count) == 1);
9808                 btrfs_put_block_group(block_group);
9809
9810                 spin_lock(&info->block_group_cache_lock);
9811         }
9812         spin_unlock(&info->block_group_cache_lock);
9813
9814         /* now that all the block groups are freed, go through and
9815          * free all the space_info structs.  This is only called during
9816          * the final stages of unmount, and so we know nobody is
9817          * using them.  We call synchronize_rcu() once before we start,
9818          * just to be on the safe side.
9819          */
9820         synchronize_rcu();
9821
9822         release_global_block_rsv(info);
9823
9824         while (!list_empty(&info->space_info)) {
9825                 int i;
9826
9827                 space_info = list_entry(info->space_info.next,
9828                                         struct btrfs_space_info,
9829                                         list);
9830
9831                 /*
9832                  * Do not hide this behind enospc_debug, this is actually
9833                  * important and indicates a real bug if this happens.
9834                  */
9835                 if (WARN_ON(space_info->bytes_pinned > 0 ||
9836                             space_info->bytes_reserved > 0 ||
9837                             space_info->bytes_may_use > 0))
9838                         dump_space_info(info, space_info, 0, 0);
9839                 list_del(&space_info->list);
9840                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9841                         struct kobject *kobj;
9842                         kobj = space_info->block_group_kobjs[i];
9843                         space_info->block_group_kobjs[i] = NULL;
9844                         if (kobj) {
9845                                 kobject_del(kobj);
9846                                 kobject_put(kobj);
9847                         }
9848                 }
9849                 kobject_del(&space_info->kobj);
9850                 kobject_put(&space_info->kobj);
9851         }
9852         return 0;
9853 }
9854
9855 static void __link_block_group(struct btrfs_space_info *space_info,
9856                                struct btrfs_block_group_cache *cache)
9857 {
9858         int index = get_block_group_index(cache);
9859         bool first = false;
9860
9861         down_write(&space_info->groups_sem);
9862         if (list_empty(&space_info->block_groups[index]))
9863                 first = true;
9864         list_add_tail(&cache->list, &space_info->block_groups[index]);
9865         up_write(&space_info->groups_sem);
9866
9867         if (first) {
9868                 struct raid_kobject *rkobj;
9869                 int ret;
9870
9871                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9872                 if (!rkobj)
9873                         goto out_err;
9874                 rkobj->raid_type = index;
9875                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9876                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9877                                   "%s", get_raid_name(index));
9878                 if (ret) {
9879                         kobject_put(&rkobj->kobj);
9880                         goto out_err;
9881                 }
9882                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9883         }
9884
9885         return;
9886 out_err:
9887         btrfs_warn(cache->fs_info,
9888                    "failed to add kobject for block cache, ignoring");
9889 }
9890
9891 static struct btrfs_block_group_cache *
9892 btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
9893                                u64 start, u64 size)
9894 {
9895         struct btrfs_block_group_cache *cache;
9896
9897         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9898         if (!cache)
9899                 return NULL;
9900
9901         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9902                                         GFP_NOFS);
9903         if (!cache->free_space_ctl) {
9904                 kfree(cache);
9905                 return NULL;
9906         }
9907
9908         cache->key.objectid = start;
9909         cache->key.offset = size;
9910         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9911
9912         cache->sectorsize = fs_info->sectorsize;
9913         cache->fs_info = fs_info;
9914         cache->full_stripe_len = btrfs_full_stripe_len(fs_info,
9915                                                        &fs_info->mapping_tree,
9916                                                        start);
9917         set_free_space_tree_thresholds(cache);
9918
9919         atomic_set(&cache->count, 1);
9920         spin_lock_init(&cache->lock);
9921         init_rwsem(&cache->data_rwsem);
9922         INIT_LIST_HEAD(&cache->list);
9923         INIT_LIST_HEAD(&cache->cluster_list);
9924         INIT_LIST_HEAD(&cache->bg_list);
9925         INIT_LIST_HEAD(&cache->ro_list);
9926         INIT_LIST_HEAD(&cache->dirty_list);
9927         INIT_LIST_HEAD(&cache->io_list);
9928         btrfs_init_free_space_ctl(cache);
9929         atomic_set(&cache->trimming, 0);
9930         mutex_init(&cache->free_space_lock);
9931         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
9932
9933         return cache;
9934 }
9935
9936 int btrfs_read_block_groups(struct btrfs_fs_info *info)
9937 {
9938         struct btrfs_path *path;
9939         int ret;
9940         struct btrfs_block_group_cache *cache;
9941         struct btrfs_space_info *space_info;
9942         struct btrfs_key key;
9943         struct btrfs_key found_key;
9944         struct extent_buffer *leaf;
9945         int need_clear = 0;
9946         u64 cache_gen;
9947         u64 feature;
9948         int mixed;
9949
9950         feature = btrfs_super_incompat_flags(info->super_copy);
9951         mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
9952
9953         key.objectid = 0;
9954         key.offset = 0;
9955         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9956         path = btrfs_alloc_path();
9957         if (!path)
9958                 return -ENOMEM;
9959         path->reada = READA_FORWARD;
9960
9961         cache_gen = btrfs_super_cache_generation(info->super_copy);
9962         if (btrfs_test_opt(info, SPACE_CACHE) &&
9963             btrfs_super_generation(info->super_copy) != cache_gen)
9964                 need_clear = 1;
9965         if (btrfs_test_opt(info, CLEAR_CACHE))
9966                 need_clear = 1;
9967
9968         while (1) {
9969                 ret = find_first_block_group(info, path, &key);
9970                 if (ret > 0)
9971                         break;
9972                 if (ret != 0)
9973                         goto error;
9974
9975                 leaf = path->nodes[0];
9976                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9977
9978                 cache = btrfs_create_block_group_cache(info, found_key.objectid,
9979                                                        found_key.offset);
9980                 if (!cache) {
9981                         ret = -ENOMEM;
9982                         goto error;
9983                 }
9984
9985                 if (need_clear) {
9986                         /*
9987                          * When we mount with old space cache, we need to
9988                          * set BTRFS_DC_CLEAR and set dirty flag.
9989                          *
9990                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9991                          *    truncate the old free space cache inode and
9992                          *    setup a new one.
9993                          * b) Setting 'dirty flag' makes sure that we flush
9994                          *    the new space cache info onto disk.
9995                          */
9996                         if (btrfs_test_opt(info, SPACE_CACHE))
9997                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9998                 }
9999
10000                 read_extent_buffer(leaf, &cache->item,
10001                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
10002                                    sizeof(cache->item));
10003                 cache->flags = btrfs_block_group_flags(&cache->item);
10004                 if (!mixed &&
10005                     ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
10006                     (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
10007                         btrfs_err(info,
10008 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
10009                                   cache->key.objectid);
10010                         ret = -EINVAL;
10011                         goto error;
10012                 }
10013
10014                 key.objectid = found_key.objectid + found_key.offset;
10015                 btrfs_release_path(path);
10016
10017                 /*
10018                  * We need to exclude the super stripes now so that the space
10019                  * info has super bytes accounted for, otherwise we'll think
10020                  * we have more space than we actually do.
10021                  */
10022                 ret = exclude_super_stripes(info, cache);
10023                 if (ret) {
10024                         /*
10025                          * We may have excluded something, so call this just in
10026                          * case.
10027                          */
10028                         free_excluded_extents(info, cache);
10029                         btrfs_put_block_group(cache);
10030                         goto error;
10031                 }
10032
10033                 /*
10034                  * check for two cases, either we are full, and therefore
10035                  * don't need to bother with the caching work since we won't
10036                  * find any space, or we are empty, and we can just add all
10037                  * the space in and be done with it.  This saves us _alot_ of
10038                  * time, particularly in the full case.
10039                  */
10040                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10041                         cache->last_byte_to_unpin = (u64)-1;
10042                         cache->cached = BTRFS_CACHE_FINISHED;
10043                         free_excluded_extents(info, cache);
10044                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10045                         cache->last_byte_to_unpin = (u64)-1;
10046                         cache->cached = BTRFS_CACHE_FINISHED;
10047                         add_new_free_space(cache, info,
10048                                            found_key.objectid,
10049                                            found_key.objectid +
10050                                            found_key.offset);
10051                         free_excluded_extents(info, cache);
10052                 }
10053
10054                 ret = btrfs_add_block_group_cache(info, cache);
10055                 if (ret) {
10056                         btrfs_remove_free_space_cache(cache);
10057                         btrfs_put_block_group(cache);
10058                         goto error;
10059                 }
10060
10061                 trace_btrfs_add_block_group(info, cache, 0);
10062                 ret = update_space_info(info, cache->flags, found_key.offset,
10063                                         btrfs_block_group_used(&cache->item),
10064                                         cache->bytes_super, &space_info);
10065                 if (ret) {
10066                         btrfs_remove_free_space_cache(cache);
10067                         spin_lock(&info->block_group_cache_lock);
10068                         rb_erase(&cache->cache_node,
10069                                  &info->block_group_cache_tree);
10070                         RB_CLEAR_NODE(&cache->cache_node);
10071                         spin_unlock(&info->block_group_cache_lock);
10072                         btrfs_put_block_group(cache);
10073                         goto error;
10074                 }
10075
10076                 cache->space_info = space_info;
10077
10078                 __link_block_group(space_info, cache);
10079
10080                 set_avail_alloc_bits(info, cache->flags);
10081                 if (btrfs_chunk_readonly(info, cache->key.objectid)) {
10082                         inc_block_group_ro(cache, 1);
10083                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10084                         spin_lock(&info->unused_bgs_lock);
10085                         /* Should always be true but just in case. */
10086                         if (list_empty(&cache->bg_list)) {
10087                                 btrfs_get_block_group(cache);
10088                                 list_add_tail(&cache->bg_list,
10089                                               &info->unused_bgs);
10090                         }
10091                         spin_unlock(&info->unused_bgs_lock);
10092                 }
10093         }
10094
10095         list_for_each_entry_rcu(space_info, &info->space_info, list) {
10096                 if (!(get_alloc_profile(info, space_info->flags) &
10097                       (BTRFS_BLOCK_GROUP_RAID10 |
10098                        BTRFS_BLOCK_GROUP_RAID1 |
10099                        BTRFS_BLOCK_GROUP_RAID5 |
10100                        BTRFS_BLOCK_GROUP_RAID6 |
10101                        BTRFS_BLOCK_GROUP_DUP)))
10102                         continue;
10103                 /*
10104                  * avoid allocating from un-mirrored block group if there are
10105                  * mirrored block groups.
10106                  */
10107                 list_for_each_entry(cache,
10108                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10109                                 list)
10110                         inc_block_group_ro(cache, 1);
10111                 list_for_each_entry(cache,
10112                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10113                                 list)
10114                         inc_block_group_ro(cache, 1);
10115         }
10116
10117         init_global_block_rsv(info);
10118         ret = 0;
10119 error:
10120         btrfs_free_path(path);
10121         return ret;
10122 }
10123
10124 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
10125                                        struct btrfs_fs_info *fs_info)
10126 {
10127         struct btrfs_block_group_cache *block_group, *tmp;
10128         struct btrfs_root *extent_root = fs_info->extent_root;
10129         struct btrfs_block_group_item item;
10130         struct btrfs_key key;
10131         int ret = 0;
10132         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10133
10134         trans->can_flush_pending_bgs = false;
10135         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10136                 if (ret)
10137                         goto next;
10138
10139                 spin_lock(&block_group->lock);
10140                 memcpy(&item, &block_group->item, sizeof(item));
10141                 memcpy(&key, &block_group->key, sizeof(key));
10142                 spin_unlock(&block_group->lock);
10143
10144                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10145                                         sizeof(item));
10146                 if (ret)
10147                         btrfs_abort_transaction(trans, ret);
10148                 ret = btrfs_finish_chunk_alloc(trans, fs_info, key.objectid,
10149                                                key.offset);
10150                 if (ret)
10151                         btrfs_abort_transaction(trans, ret);
10152                 add_block_group_free_space(trans, fs_info, block_group);
10153                 /* already aborted the transaction if it failed. */
10154 next:
10155                 list_del_init(&block_group->bg_list);
10156         }
10157         trans->can_flush_pending_bgs = can_flush_pending_bgs;
10158 }
10159
10160 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10161                            struct btrfs_fs_info *fs_info, u64 bytes_used,
10162                            u64 type, u64 chunk_objectid, u64 chunk_offset,
10163                            u64 size)
10164 {
10165         struct btrfs_block_group_cache *cache;
10166         int ret;
10167
10168         btrfs_set_log_full_commit(fs_info, trans);
10169
10170         cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
10171         if (!cache)
10172                 return -ENOMEM;
10173
10174         btrfs_set_block_group_used(&cache->item, bytes_used);
10175         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
10176         btrfs_set_block_group_flags(&cache->item, type);
10177
10178         cache->flags = type;
10179         cache->last_byte_to_unpin = (u64)-1;
10180         cache->cached = BTRFS_CACHE_FINISHED;
10181         cache->needs_free_space = 1;
10182         ret = exclude_super_stripes(fs_info, cache);
10183         if (ret) {
10184                 /*
10185                  * We may have excluded something, so call this just in
10186                  * case.
10187                  */
10188                 free_excluded_extents(fs_info, cache);
10189                 btrfs_put_block_group(cache);
10190                 return ret;
10191         }
10192
10193         add_new_free_space(cache, fs_info, chunk_offset, chunk_offset + size);
10194
10195         free_excluded_extents(fs_info, cache);
10196
10197 #ifdef CONFIG_BTRFS_DEBUG
10198         if (btrfs_should_fragment_free_space(cache)) {
10199                 u64 new_bytes_used = size - bytes_used;
10200
10201                 bytes_used += new_bytes_used >> 1;
10202                 fragment_free_space(cache);
10203         }
10204 #endif
10205         /*
10206          * Call to ensure the corresponding space_info object is created and
10207          * assigned to our block group, but don't update its counters just yet.
10208          * We want our bg to be added to the rbtree with its ->space_info set.
10209          */
10210         ret = update_space_info(fs_info, cache->flags, 0, 0, 0,
10211                                 &cache->space_info);
10212         if (ret) {
10213                 btrfs_remove_free_space_cache(cache);
10214                 btrfs_put_block_group(cache);
10215                 return ret;
10216         }
10217
10218         ret = btrfs_add_block_group_cache(fs_info, cache);
10219         if (ret) {
10220                 btrfs_remove_free_space_cache(cache);
10221                 btrfs_put_block_group(cache);
10222                 return ret;
10223         }
10224
10225         /*
10226          * Now that our block group has its ->space_info set and is inserted in
10227          * the rbtree, update the space info's counters.
10228          */
10229         trace_btrfs_add_block_group(fs_info, cache, 1);
10230         ret = update_space_info(fs_info, cache->flags, size, bytes_used,
10231                                 cache->bytes_super, &cache->space_info);
10232         if (ret) {
10233                 btrfs_remove_free_space_cache(cache);
10234                 spin_lock(&fs_info->block_group_cache_lock);
10235                 rb_erase(&cache->cache_node,
10236                          &fs_info->block_group_cache_tree);
10237                 RB_CLEAR_NODE(&cache->cache_node);
10238                 spin_unlock(&fs_info->block_group_cache_lock);
10239                 btrfs_put_block_group(cache);
10240                 return ret;
10241         }
10242         update_global_block_rsv(fs_info);
10243
10244         __link_block_group(cache->space_info, cache);
10245
10246         list_add_tail(&cache->bg_list, &trans->new_bgs);
10247
10248         set_avail_alloc_bits(fs_info, type);
10249         return 0;
10250 }
10251
10252 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10253 {
10254         u64 extra_flags = chunk_to_extended(flags) &
10255                                 BTRFS_EXTENDED_PROFILE_MASK;
10256
10257         write_seqlock(&fs_info->profiles_lock);
10258         if (flags & BTRFS_BLOCK_GROUP_DATA)
10259                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10260         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10261                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10262         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10263                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10264         write_sequnlock(&fs_info->profiles_lock);
10265 }
10266
10267 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10268                              struct btrfs_fs_info *fs_info, u64 group_start,
10269                              struct extent_map *em)
10270 {
10271         struct btrfs_root *root = fs_info->extent_root;
10272         struct btrfs_path *path;
10273         struct btrfs_block_group_cache *block_group;
10274         struct btrfs_free_cluster *cluster;
10275         struct btrfs_root *tree_root = fs_info->tree_root;
10276         struct btrfs_key key;
10277         struct inode *inode;
10278         struct kobject *kobj = NULL;
10279         int ret;
10280         int index;
10281         int factor;
10282         struct btrfs_caching_control *caching_ctl = NULL;
10283         bool remove_em;
10284
10285         block_group = btrfs_lookup_block_group(fs_info, group_start);
10286         BUG_ON(!block_group);
10287         BUG_ON(!block_group->ro);
10288
10289         /*
10290          * Free the reserved super bytes from this block group before
10291          * remove it.
10292          */
10293         free_excluded_extents(fs_info, block_group);
10294
10295         memcpy(&key, &block_group->key, sizeof(key));
10296         index = get_block_group_index(block_group);
10297         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10298                                   BTRFS_BLOCK_GROUP_RAID1 |
10299                                   BTRFS_BLOCK_GROUP_RAID10))
10300                 factor = 2;
10301         else
10302                 factor = 1;
10303
10304         /* make sure this block group isn't part of an allocation cluster */
10305         cluster = &fs_info->data_alloc_cluster;
10306         spin_lock(&cluster->refill_lock);
10307         btrfs_return_cluster_to_free_space(block_group, cluster);
10308         spin_unlock(&cluster->refill_lock);
10309
10310         /*
10311          * make sure this block group isn't part of a metadata
10312          * allocation cluster
10313          */
10314         cluster = &fs_info->meta_alloc_cluster;
10315         spin_lock(&cluster->refill_lock);
10316         btrfs_return_cluster_to_free_space(block_group, cluster);
10317         spin_unlock(&cluster->refill_lock);
10318
10319         path = btrfs_alloc_path();
10320         if (!path) {
10321                 ret = -ENOMEM;
10322                 goto out;
10323         }
10324
10325         /*
10326          * get the inode first so any iput calls done for the io_list
10327          * aren't the final iput (no unlinks allowed now)
10328          */
10329         inode = lookup_free_space_inode(fs_info, block_group, path);
10330
10331         mutex_lock(&trans->transaction->cache_write_mutex);
10332         /*
10333          * make sure our free spache cache IO is done before remove the
10334          * free space inode
10335          */
10336         spin_lock(&trans->transaction->dirty_bgs_lock);
10337         if (!list_empty(&block_group->io_list)) {
10338                 list_del_init(&block_group->io_list);
10339
10340                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10341
10342                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10343                 btrfs_wait_cache_io(trans, block_group, path);
10344                 btrfs_put_block_group(block_group);
10345                 spin_lock(&trans->transaction->dirty_bgs_lock);
10346         }
10347
10348         if (!list_empty(&block_group->dirty_list)) {
10349                 list_del_init(&block_group->dirty_list);
10350                 btrfs_put_block_group(block_group);
10351         }
10352         spin_unlock(&trans->transaction->dirty_bgs_lock);
10353         mutex_unlock(&trans->transaction->cache_write_mutex);
10354
10355         if (!IS_ERR(inode)) {
10356                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10357                 if (ret) {
10358                         btrfs_add_delayed_iput(inode);
10359                         goto out;
10360                 }
10361                 clear_nlink(inode);
10362                 /* One for the block groups ref */
10363                 spin_lock(&block_group->lock);
10364                 if (block_group->iref) {
10365                         block_group->iref = 0;
10366                         block_group->inode = NULL;
10367                         spin_unlock(&block_group->lock);
10368                         iput(inode);
10369                 } else {
10370                         spin_unlock(&block_group->lock);
10371                 }
10372                 /* One for our lookup ref */
10373                 btrfs_add_delayed_iput(inode);
10374         }
10375
10376         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10377         key.offset = block_group->key.objectid;
10378         key.type = 0;
10379
10380         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10381         if (ret < 0)
10382                 goto out;
10383         if (ret > 0)
10384                 btrfs_release_path(path);
10385         if (ret == 0) {
10386                 ret = btrfs_del_item(trans, tree_root, path);
10387                 if (ret)
10388                         goto out;
10389                 btrfs_release_path(path);
10390         }
10391
10392         spin_lock(&fs_info->block_group_cache_lock);
10393         rb_erase(&block_group->cache_node,
10394                  &fs_info->block_group_cache_tree);
10395         RB_CLEAR_NODE(&block_group->cache_node);
10396
10397         if (fs_info->first_logical_byte == block_group->key.objectid)
10398                 fs_info->first_logical_byte = (u64)-1;
10399         spin_unlock(&fs_info->block_group_cache_lock);
10400
10401         down_write(&block_group->space_info->groups_sem);
10402         /*
10403          * we must use list_del_init so people can check to see if they
10404          * are still on the list after taking the semaphore
10405          */
10406         list_del_init(&block_group->list);
10407         if (list_empty(&block_group->space_info->block_groups[index])) {
10408                 kobj = block_group->space_info->block_group_kobjs[index];
10409                 block_group->space_info->block_group_kobjs[index] = NULL;
10410                 clear_avail_alloc_bits(fs_info, block_group->flags);
10411         }
10412         up_write(&block_group->space_info->groups_sem);
10413         if (kobj) {
10414                 kobject_del(kobj);
10415                 kobject_put(kobj);
10416         }
10417
10418         if (block_group->has_caching_ctl)
10419                 caching_ctl = get_caching_control(block_group);
10420         if (block_group->cached == BTRFS_CACHE_STARTED)
10421                 wait_block_group_cache_done(block_group);
10422         if (block_group->has_caching_ctl) {
10423                 down_write(&fs_info->commit_root_sem);
10424                 if (!caching_ctl) {
10425                         struct btrfs_caching_control *ctl;
10426
10427                         list_for_each_entry(ctl,
10428                                     &fs_info->caching_block_groups, list)
10429                                 if (ctl->block_group == block_group) {
10430                                         caching_ctl = ctl;
10431                                         refcount_inc(&caching_ctl->count);
10432                                         break;
10433                                 }
10434                 }
10435                 if (caching_ctl)
10436                         list_del_init(&caching_ctl->list);
10437                 up_write(&fs_info->commit_root_sem);
10438                 if (caching_ctl) {
10439                         /* Once for the caching bgs list and once for us. */
10440                         put_caching_control(caching_ctl);
10441                         put_caching_control(caching_ctl);
10442                 }
10443         }
10444
10445         spin_lock(&trans->transaction->dirty_bgs_lock);
10446         if (!list_empty(&block_group->dirty_list)) {
10447                 WARN_ON(1);
10448         }
10449         if (!list_empty(&block_group->io_list)) {
10450                 WARN_ON(1);
10451         }
10452         spin_unlock(&trans->transaction->dirty_bgs_lock);
10453         btrfs_remove_free_space_cache(block_group);
10454
10455         spin_lock(&block_group->space_info->lock);
10456         list_del_init(&block_group->ro_list);
10457
10458         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
10459                 WARN_ON(block_group->space_info->total_bytes
10460                         < block_group->key.offset);
10461                 WARN_ON(block_group->space_info->bytes_readonly
10462                         < block_group->key.offset);
10463                 WARN_ON(block_group->space_info->disk_total
10464                         < block_group->key.offset * factor);
10465         }
10466         block_group->space_info->total_bytes -= block_group->key.offset;
10467         block_group->space_info->bytes_readonly -= block_group->key.offset;
10468         block_group->space_info->disk_total -= block_group->key.offset * factor;
10469
10470         spin_unlock(&block_group->space_info->lock);
10471
10472         memcpy(&key, &block_group->key, sizeof(key));
10473
10474         mutex_lock(&fs_info->chunk_mutex);
10475         if (!list_empty(&em->list)) {
10476                 /* We're in the transaction->pending_chunks list. */
10477                 free_extent_map(em);
10478         }
10479         spin_lock(&block_group->lock);
10480         block_group->removed = 1;
10481         /*
10482          * At this point trimming can't start on this block group, because we
10483          * removed the block group from the tree fs_info->block_group_cache_tree
10484          * so no one can't find it anymore and even if someone already got this
10485          * block group before we removed it from the rbtree, they have already
10486          * incremented block_group->trimming - if they didn't, they won't find
10487          * any free space entries because we already removed them all when we
10488          * called btrfs_remove_free_space_cache().
10489          *
10490          * And we must not remove the extent map from the fs_info->mapping_tree
10491          * to prevent the same logical address range and physical device space
10492          * ranges from being reused for a new block group. This is because our
10493          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10494          * completely transactionless, so while it is trimming a range the
10495          * currently running transaction might finish and a new one start,
10496          * allowing for new block groups to be created that can reuse the same
10497          * physical device locations unless we take this special care.
10498          *
10499          * There may also be an implicit trim operation if the file system
10500          * is mounted with -odiscard. The same protections must remain
10501          * in place until the extents have been discarded completely when
10502          * the transaction commit has completed.
10503          */
10504         remove_em = (atomic_read(&block_group->trimming) == 0);
10505         /*
10506          * Make sure a trimmer task always sees the em in the pinned_chunks list
10507          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10508          * before checking block_group->removed).
10509          */
10510         if (!remove_em) {
10511                 /*
10512                  * Our em might be in trans->transaction->pending_chunks which
10513                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10514                  * and so is the fs_info->pinned_chunks list.
10515                  *
10516                  * So at this point we must be holding the chunk_mutex to avoid
10517                  * any races with chunk allocation (more specifically at
10518                  * volumes.c:contains_pending_extent()), to ensure it always
10519                  * sees the em, either in the pending_chunks list or in the
10520                  * pinned_chunks list.
10521                  */
10522                 list_move_tail(&em->list, &fs_info->pinned_chunks);
10523         }
10524         spin_unlock(&block_group->lock);
10525
10526         if (remove_em) {
10527                 struct extent_map_tree *em_tree;
10528
10529                 em_tree = &fs_info->mapping_tree.map_tree;
10530                 write_lock(&em_tree->lock);
10531                 /*
10532                  * The em might be in the pending_chunks list, so make sure the
10533                  * chunk mutex is locked, since remove_extent_mapping() will
10534                  * delete us from that list.
10535                  */
10536                 remove_extent_mapping(em_tree, em);
10537                 write_unlock(&em_tree->lock);
10538                 /* once for the tree */
10539                 free_extent_map(em);
10540         }
10541
10542         mutex_unlock(&fs_info->chunk_mutex);
10543
10544         ret = remove_block_group_free_space(trans, fs_info, block_group);
10545         if (ret)
10546                 goto out;
10547
10548         btrfs_put_block_group(block_group);
10549         btrfs_put_block_group(block_group);
10550
10551         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10552         if (ret > 0)
10553                 ret = -EIO;
10554         if (ret < 0)
10555                 goto out;
10556
10557         ret = btrfs_del_item(trans, root, path);
10558 out:
10559         btrfs_free_path(path);
10560         return ret;
10561 }
10562
10563 struct btrfs_trans_handle *
10564 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10565                                      const u64 chunk_offset)
10566 {
10567         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10568         struct extent_map *em;
10569         struct map_lookup *map;
10570         unsigned int num_items;
10571
10572         read_lock(&em_tree->lock);
10573         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10574         read_unlock(&em_tree->lock);
10575         ASSERT(em && em->start == chunk_offset);
10576
10577         /*
10578          * We need to reserve 3 + N units from the metadata space info in order
10579          * to remove a block group (done at btrfs_remove_chunk() and at
10580          * btrfs_remove_block_group()), which are used for:
10581          *
10582          * 1 unit for adding the free space inode's orphan (located in the tree
10583          * of tree roots).
10584          * 1 unit for deleting the block group item (located in the extent
10585          * tree).
10586          * 1 unit for deleting the free space item (located in tree of tree
10587          * roots).
10588          * N units for deleting N device extent items corresponding to each
10589          * stripe (located in the device tree).
10590          *
10591          * In order to remove a block group we also need to reserve units in the
10592          * system space info in order to update the chunk tree (update one or
10593          * more device items and remove one chunk item), but this is done at
10594          * btrfs_remove_chunk() through a call to check_system_chunk().
10595          */
10596         map = em->map_lookup;
10597         num_items = 3 + map->num_stripes;
10598         free_extent_map(em);
10599
10600         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10601                                                            num_items, 1);
10602 }
10603
10604 /*
10605  * Process the unused_bgs list and remove any that don't have any allocated
10606  * space inside of them.
10607  */
10608 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10609 {
10610         struct btrfs_block_group_cache *block_group;
10611         struct btrfs_space_info *space_info;
10612         struct btrfs_trans_handle *trans;
10613         int ret = 0;
10614
10615         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10616                 return;
10617
10618         spin_lock(&fs_info->unused_bgs_lock);
10619         while (!list_empty(&fs_info->unused_bgs)) {
10620                 u64 start, end;
10621                 int trimming;
10622
10623                 block_group = list_first_entry(&fs_info->unused_bgs,
10624                                                struct btrfs_block_group_cache,
10625                                                bg_list);
10626                 list_del_init(&block_group->bg_list);
10627
10628                 space_info = block_group->space_info;
10629
10630                 if (ret || btrfs_mixed_space_info(space_info)) {
10631                         btrfs_put_block_group(block_group);
10632                         continue;
10633                 }
10634                 spin_unlock(&fs_info->unused_bgs_lock);
10635
10636                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10637
10638                 /* Don't want to race with allocators so take the groups_sem */
10639                 down_write(&space_info->groups_sem);
10640                 spin_lock(&block_group->lock);
10641                 if (block_group->reserved ||
10642                     btrfs_block_group_used(&block_group->item) ||
10643                     block_group->ro ||
10644                     list_is_singular(&block_group->list)) {
10645                         /*
10646                          * We want to bail if we made new allocations or have
10647                          * outstanding allocations in this block group.  We do
10648                          * the ro check in case balance is currently acting on
10649                          * this block group.
10650                          */
10651                         spin_unlock(&block_group->lock);
10652                         up_write(&space_info->groups_sem);
10653                         goto next;
10654                 }
10655                 spin_unlock(&block_group->lock);
10656
10657                 /* We don't want to force the issue, only flip if it's ok. */
10658                 ret = inc_block_group_ro(block_group, 0);
10659                 up_write(&space_info->groups_sem);
10660                 if (ret < 0) {
10661                         ret = 0;
10662                         goto next;
10663                 }
10664
10665                 /*
10666                  * Want to do this before we do anything else so we can recover
10667                  * properly if we fail to join the transaction.
10668                  */
10669                 trans = btrfs_start_trans_remove_block_group(fs_info,
10670                                                      block_group->key.objectid);
10671                 if (IS_ERR(trans)) {
10672                         btrfs_dec_block_group_ro(block_group);
10673                         ret = PTR_ERR(trans);
10674                         goto next;
10675                 }
10676
10677                 /*
10678                  * We could have pending pinned extents for this block group,
10679                  * just delete them, we don't care about them anymore.
10680                  */
10681                 start = block_group->key.objectid;
10682                 end = start + block_group->key.offset - 1;
10683                 /*
10684                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10685                  * btrfs_finish_extent_commit(). If we are at transaction N,
10686                  * another task might be running finish_extent_commit() for the
10687                  * previous transaction N - 1, and have seen a range belonging
10688                  * to the block group in freed_extents[] before we were able to
10689                  * clear the whole block group range from freed_extents[]. This
10690                  * means that task can lookup for the block group after we
10691                  * unpinned it from freed_extents[] and removed it, leading to
10692                  * a BUG_ON() at btrfs_unpin_extent_range().
10693                  */
10694                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10695                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10696                                   EXTENT_DIRTY);
10697                 if (ret) {
10698                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10699                         btrfs_dec_block_group_ro(block_group);
10700                         goto end_trans;
10701                 }
10702                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10703                                   EXTENT_DIRTY);
10704                 if (ret) {
10705                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10706                         btrfs_dec_block_group_ro(block_group);
10707                         goto end_trans;
10708                 }
10709                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10710
10711                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10712                 spin_lock(&space_info->lock);
10713                 spin_lock(&block_group->lock);
10714
10715                 space_info->bytes_pinned -= block_group->pinned;
10716                 space_info->bytes_readonly += block_group->pinned;
10717                 percpu_counter_add(&space_info->total_bytes_pinned,
10718                                    -block_group->pinned);
10719                 block_group->pinned = 0;
10720
10721                 spin_unlock(&block_group->lock);
10722                 spin_unlock(&space_info->lock);
10723
10724                 /* DISCARD can flip during remount */
10725                 trimming = btrfs_test_opt(fs_info, DISCARD);
10726
10727                 /* Implicit trim during transaction commit. */
10728                 if (trimming)
10729                         btrfs_get_block_group_trimming(block_group);
10730
10731                 /*
10732                  * Btrfs_remove_chunk will abort the transaction if things go
10733                  * horribly wrong.
10734                  */
10735                 ret = btrfs_remove_chunk(trans, fs_info,
10736                                          block_group->key.objectid);
10737
10738                 if (ret) {
10739                         if (trimming)
10740                                 btrfs_put_block_group_trimming(block_group);
10741                         goto end_trans;
10742                 }
10743
10744                 /*
10745                  * If we're not mounted with -odiscard, we can just forget
10746                  * about this block group. Otherwise we'll need to wait
10747                  * until transaction commit to do the actual discard.
10748                  */
10749                 if (trimming) {
10750                         spin_lock(&fs_info->unused_bgs_lock);
10751                         /*
10752                          * A concurrent scrub might have added us to the list
10753                          * fs_info->unused_bgs, so use a list_move operation
10754                          * to add the block group to the deleted_bgs list.
10755                          */
10756                         list_move(&block_group->bg_list,
10757                                   &trans->transaction->deleted_bgs);
10758                         spin_unlock(&fs_info->unused_bgs_lock);
10759                         btrfs_get_block_group(block_group);
10760                 }
10761 end_trans:
10762                 btrfs_end_transaction(trans);
10763 next:
10764                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10765                 btrfs_put_block_group(block_group);
10766                 spin_lock(&fs_info->unused_bgs_lock);
10767         }
10768         spin_unlock(&fs_info->unused_bgs_lock);
10769 }
10770
10771 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10772 {
10773         struct btrfs_space_info *space_info;
10774         struct btrfs_super_block *disk_super;
10775         u64 features;
10776         u64 flags;
10777         int mixed = 0;
10778         int ret;
10779
10780         disk_super = fs_info->super_copy;
10781         if (!btrfs_super_root(disk_super))
10782                 return -EINVAL;
10783
10784         features = btrfs_super_incompat_flags(disk_super);
10785         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10786                 mixed = 1;
10787
10788         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10789         ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10790         if (ret)
10791                 goto out;
10792
10793         if (mixed) {
10794                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10795                 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10796         } else {
10797                 flags = BTRFS_BLOCK_GROUP_METADATA;
10798                 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10799                 if (ret)
10800                         goto out;
10801
10802                 flags = BTRFS_BLOCK_GROUP_DATA;
10803                 ret = update_space_info(fs_info, flags, 0, 0, 0, &space_info);
10804         }
10805 out:
10806         return ret;
10807 }
10808
10809 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
10810                                    u64 start, u64 end)
10811 {
10812         return unpin_extent_range(fs_info, start, end, false);
10813 }
10814
10815 /*
10816  * It used to be that old block groups would be left around forever.
10817  * Iterating over them would be enough to trim unused space.  Since we
10818  * now automatically remove them, we also need to iterate over unallocated
10819  * space.
10820  *
10821  * We don't want a transaction for this since the discard may take a
10822  * substantial amount of time.  We don't require that a transaction be
10823  * running, but we do need to take a running transaction into account
10824  * to ensure that we're not discarding chunks that were released in
10825  * the current transaction.
10826  *
10827  * Holding the chunks lock will prevent other threads from allocating
10828  * or releasing chunks, but it won't prevent a running transaction
10829  * from committing and releasing the memory that the pending chunks
10830  * list head uses.  For that, we need to take a reference to the
10831  * transaction.
10832  */
10833 static int btrfs_trim_free_extents(struct btrfs_device *device,
10834                                    u64 minlen, u64 *trimmed)
10835 {
10836         u64 start = 0, len = 0;
10837         int ret;
10838
10839         *trimmed = 0;
10840
10841         /* Not writeable = nothing to do. */
10842         if (!device->writeable)
10843                 return 0;
10844
10845         /* No free space = nothing to do. */
10846         if (device->total_bytes <= device->bytes_used)
10847                 return 0;
10848
10849         ret = 0;
10850
10851         while (1) {
10852                 struct btrfs_fs_info *fs_info = device->fs_info;
10853                 struct btrfs_transaction *trans;
10854                 u64 bytes;
10855
10856                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10857                 if (ret)
10858                         return ret;
10859
10860                 down_read(&fs_info->commit_root_sem);
10861
10862                 spin_lock(&fs_info->trans_lock);
10863                 trans = fs_info->running_transaction;
10864                 if (trans)
10865                         refcount_inc(&trans->use_count);
10866                 spin_unlock(&fs_info->trans_lock);
10867
10868                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10869                                                  &start, &len);
10870                 if (trans)
10871                         btrfs_put_transaction(trans);
10872
10873                 if (ret) {
10874                         up_read(&fs_info->commit_root_sem);
10875                         mutex_unlock(&fs_info->chunk_mutex);
10876                         if (ret == -ENOSPC)
10877                                 ret = 0;
10878                         break;
10879                 }
10880
10881                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10882                 up_read(&fs_info->commit_root_sem);
10883                 mutex_unlock(&fs_info->chunk_mutex);
10884
10885                 if (ret)
10886                         break;
10887
10888                 start += len;
10889                 *trimmed += bytes;
10890
10891                 if (fatal_signal_pending(current)) {
10892                         ret = -ERESTARTSYS;
10893                         break;
10894                 }
10895
10896                 cond_resched();
10897         }
10898
10899         return ret;
10900 }
10901
10902 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
10903 {
10904         struct btrfs_block_group_cache *cache = NULL;
10905         struct btrfs_device *device;
10906         struct list_head *devices;
10907         u64 group_trimmed;
10908         u64 start;
10909         u64 end;
10910         u64 trimmed = 0;
10911         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10912         int ret = 0;
10913
10914         /*
10915          * try to trim all FS space, our block group may start from non-zero.
10916          */
10917         if (range->len == total_bytes)
10918                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10919         else
10920                 cache = btrfs_lookup_block_group(fs_info, range->start);
10921
10922         while (cache) {
10923                 if (cache->key.objectid >= (range->start + range->len)) {
10924                         btrfs_put_block_group(cache);
10925                         break;
10926                 }
10927
10928                 start = max(range->start, cache->key.objectid);
10929                 end = min(range->start + range->len,
10930                                 cache->key.objectid + cache->key.offset);
10931
10932                 if (end - start >= range->minlen) {
10933                         if (!block_group_cache_done(cache)) {
10934                                 ret = cache_block_group(cache, 0);
10935                                 if (ret) {
10936                                         btrfs_put_block_group(cache);
10937                                         break;
10938                                 }
10939                                 ret = wait_block_group_cache_done(cache);
10940                                 if (ret) {
10941                                         btrfs_put_block_group(cache);
10942                                         break;
10943                                 }
10944                         }
10945                         ret = btrfs_trim_block_group(cache,
10946                                                      &group_trimmed,
10947                                                      start,
10948                                                      end,
10949                                                      range->minlen);
10950
10951                         trimmed += group_trimmed;
10952                         if (ret) {
10953                                 btrfs_put_block_group(cache);
10954                                 break;
10955                         }
10956                 }
10957
10958                 cache = next_block_group(fs_info, cache);
10959         }
10960
10961         mutex_lock(&fs_info->fs_devices->device_list_mutex);
10962         devices = &fs_info->fs_devices->alloc_list;
10963         list_for_each_entry(device, devices, dev_alloc_list) {
10964                 ret = btrfs_trim_free_extents(device, range->minlen,
10965                                               &group_trimmed);
10966                 if (ret)
10967                         break;
10968
10969                 trimmed += group_trimmed;
10970         }
10971         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
10972
10973         range->len = trimmed;
10974         return ret;
10975 }
10976
10977 /*
10978  * btrfs_{start,end}_write_no_snapshoting() are similar to
10979  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10980  * data into the page cache through nocow before the subvolume is snapshoted,
10981  * but flush the data into disk after the snapshot creation, or to prevent
10982  * operations while snapshoting is ongoing and that cause the snapshot to be
10983  * inconsistent (writes followed by expanding truncates for example).
10984  */
10985 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
10986 {
10987         percpu_counter_dec(&root->subv_writers->counter);
10988         /*
10989          * Make sure counter is updated before we wake up waiters.
10990          */
10991         smp_mb();
10992         if (waitqueue_active(&root->subv_writers->wait))
10993                 wake_up(&root->subv_writers->wait);
10994 }
10995
10996 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
10997 {
10998         if (atomic_read(&root->will_be_snapshoted))
10999                 return 0;
11000
11001         percpu_counter_inc(&root->subv_writers->counter);
11002         /*
11003          * Make sure counter is updated before we check for snapshot creation.
11004          */
11005         smp_mb();
11006         if (atomic_read(&root->will_be_snapshoted)) {
11007                 btrfs_end_write_no_snapshoting(root);
11008                 return 0;
11009         }
11010         return 1;
11011 }
11012
11013 static int wait_snapshoting_atomic_t(atomic_t *a)
11014 {
11015         schedule();
11016         return 0;
11017 }
11018
11019 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11020 {
11021         while (true) {
11022                 int ret;
11023
11024                 ret = btrfs_start_write_no_snapshoting(root);
11025                 if (ret)
11026                         break;
11027                 wait_on_atomic_t(&root->will_be_snapshoted,
11028                                  wait_snapshoting_atomic_t,
11029                                  TASK_UNINTERRUPTIBLE);
11030         }
11031 }