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_fs_info *fs_info,
 101                                     struct btrfs_space_info *space_info,
 102                                     u64 orig_bytes,
 103                                     enum btrfs_reserve_flush_enum flush,
 104                                     bool system_chunk);
 105 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
 106                                      struct btrfs_space_info *space_info,
 107                                      u64 num_bytes);
 108 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
 109                                      struct btrfs_space_info *space_info,
 110                                      u64 num_bytes);
 111
 112 static noinline int
 113 block_group_cache_done(struct btrfs_block_group_cache *cache)
 114 {
 115         smp_mb();
 116         return cache->cached == BTRFS_CACHE_FINISHED ||
 117                 cache->cached == BTRFS_CACHE_ERROR;
 118 }
 119
 120 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 121 {
 122         return (cache->flags & bits) == bits;
 123 }
 124
 125 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 126 {
 127         atomic_inc(&cache->count);
 128 }
 129
 130 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 131 {
 132         if (atomic_dec_and_test(&cache->count)) {
 133                 WARN_ON(cache->pinned > 0);
 134                 WARN_ON(cache->reserved > 0);
 135
 136                 /*
 137                  * If not empty, someone is still holding mutex of
 138                  * full_stripe_lock, which can only be released by caller.
 139                  * And it will definitely cause use-after-free when caller
 140                  * tries to release full stripe lock.
 141                  *
 142                  * No better way to resolve, but only to warn.
 143                  */
 144                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 145                 kfree(cache->free_space_ctl);
 146                 kfree(cache);
 147         }
 148 }
 149
 150 /*
 151  * this adds the block group to the fs_info rb tree for the block group
 152  * cache
 153  */
 154 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 155                                 struct btrfs_block_group_cache *block_group)
 156 {
 157         struct rb_node **p;
 158         struct rb_node *parent = NULL;
 159         struct btrfs_block_group_cache *cache;
 160
 161         spin_lock(&info->block_group_cache_lock);
 162         p = &info->block_group_cache_tree.rb_node;
 163
 164         while (*p) {
 165                 parent = *p;
 166                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 167                                  cache_node);
 168                 if (block_group->key.objectid < cache->key.objectid) {
 169                         p = &(*p)->rb_left;
 170                 } else if (block_group->key.objectid > cache->key.objectid) {
 171                         p = &(*p)->rb_right;
 172                 } else {
 173                         spin_unlock(&info->block_group_cache_lock);
 174                         return -EEXIST;
 175                 }
 176         }
 177
 178         rb_link_node(&block_group->cache_node, parent, p);
 179         rb_insert_color(&block_group->cache_node,
 180                         &info->block_group_cache_tree);
 181
 182         if (info->first_logical_byte > block_group->key.objectid)
 183                 info->first_logical_byte = block_group->key.objectid;
 184
 185         spin_unlock(&info->block_group_cache_lock);
 186
 187         return 0;
 188 }
 189
 190 /*
 191  * This will return the block group at or after bytenr if contains is 0, else
 192  * it will return the block group that contains the bytenr
 193  */
 194 static struct btrfs_block_group_cache *
 195 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 196                               int contains)
 197 {
 198         struct btrfs_block_group_cache *cache, *ret = NULL;
 199         struct rb_node *n;
 200         u64 end, start;
 201
 202         spin_lock(&info->block_group_cache_lock);
 203         n = info->block_group_cache_tree.rb_node;
 204
 205         while (n) {
 206                 cache = rb_entry(n, struct btrfs_block_group_cache,
 207                                  cache_node);
 208                 end = cache->key.objectid + cache->key.offset - 1;
 209                 start = cache->key.objectid;
 210
 211                 if (bytenr < start) {
 212                         if (!contains && (!ret || start < ret->key.objectid))
 213                                 ret = cache;
 214                         n = n->rb_left;
 215                 } else if (bytenr > start) {
 216                         if (contains && bytenr <= end) {
 217                                 ret = cache;
 218                                 break;
 219                         }
 220                         n = n->rb_right;
 221                 } else {
 222                         ret = cache;
 223                         break;
 224                 }
 225         }
 226         if (ret) {
 227                 btrfs_get_block_group(ret);
 228                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 229                         info->first_logical_byte = ret->key.objectid;
 230         }
 231         spin_unlock(&info->block_group_cache_lock);
 232
 233         return ret;
 234 }
 235
 236 static int add_excluded_extent(struct btrfs_fs_info *fs_info,
 237                                u64 start, u64 num_bytes)
 238 {
 239         u64 end = start + num_bytes - 1;
 240         set_extent_bits(&fs_info->freed_extents[0],
 241                         start, end, EXTENT_UPTODATE);
 242         set_extent_bits(&fs_info->freed_extents[1],
 243                         start, end, EXTENT_UPTODATE);
 244         return 0;
 245 }
 246
 247 static void free_excluded_extents(struct btrfs_fs_info *fs_info,
 248                                   struct btrfs_block_group_cache *cache)
 249 {
 250         u64 start, end;
 251
 252         start = cache->key.objectid;
 253         end = start + cache->key.offset - 1;
 254
 255         clear_extent_bits(&fs_info->freed_extents[0],
 256                           start, end, EXTENT_UPTODATE);
 257         clear_extent_bits(&fs_info->freed_extents[1],
 258                           start, end, EXTENT_UPTODATE);
 259 }
 260
 261 static int exclude_super_stripes(struct btrfs_fs_info *fs_info,
 262                                  struct btrfs_block_group_cache *cache)
 263 {
 264         u64 bytenr;
 265         u64 *logical;
 266         int stripe_len;
 267         int i, nr, ret;
 268
 269         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 270                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 271                 cache->bytes_super += stripe_len;
 272                 ret = add_excluded_extent(fs_info, cache->key.objectid,
 273                                           stripe_len);
 274                 if (ret)
 275                         return ret;
 276         }
 277
 278         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 279                 bytenr = btrfs_sb_offset(i);
 280                 ret = btrfs_rmap_block(fs_info, cache->key.objectid,
 281                                        bytenr, 0, &logical, &nr, &stripe_len);
 282                 if (ret)
 283                         return ret;
 284
 285                 while (nr--) {
 286                         u64 start, len;
 287
 288                         if (logical[nr] > cache->key.objectid +
 289                             cache->key.offset)
 290                                 continue;
 291
 292                         if (logical[nr] + stripe_len <= cache->key.objectid)
 293                                 continue;
 294
 295                         start = logical[nr];
 296                         if (start < cache->key.objectid) {
 297                                 start = cache->key.objectid;
 298                                 len = (logical[nr] + stripe_len) - start;
 299                         } else {
 300                                 len = min_t(u64, stripe_len,
 301                                             cache->key.objectid +
 302                                             cache->key.offset - start);
 303                         }
 304
 305                         cache->bytes_super += len;
 306                         ret = add_excluded_extent(fs_info, start, len);
 307                         if (ret) {
 308                                 kfree(logical);
 309                                 return ret;
 310                         }
 311                 }
 312
 313                 kfree(logical);
 314         }
 315         return 0;
 316 }
 317
 318 static struct btrfs_caching_control *
 319 get_caching_control(struct btrfs_block_group_cache *cache)
 320 {
 321         struct btrfs_caching_control *ctl;
 322
 323         spin_lock(&cache->lock);
 324         if (!cache->caching_ctl) {
 325                 spin_unlock(&cache->lock);
 326                 return NULL;
 327         }
 328
 329         ctl = cache->caching_ctl;
 330         refcount_inc(&ctl->count);
 331         spin_unlock(&cache->lock);
 332         return ctl;
 333 }
 334
 335 static void put_caching_control(struct btrfs_caching_control *ctl)
 336 {
 337         if (refcount_dec_and_test(&ctl->count))
 338                 kfree(ctl);
 339 }
 340
 341 #ifdef CONFIG_BTRFS_DEBUG
 342 static void fragment_free_space(struct btrfs_block_group_cache *block_group)
 343 {
 344         struct btrfs_fs_info *fs_info = block_group->fs_info;
 345         u64 start = block_group->key.objectid;
 346         u64 len = block_group->key.offset;
 347         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 348                 fs_info->nodesize : fs_info->sectorsize;
 349         u64 step = chunk << 1;
 350
 351         while (len > chunk) {
 352                 btrfs_remove_free_space(block_group, start, chunk);
 353                 start += step;
 354                 if (len < step)
 355                         len = 0;
 356                 else
 357                         len -= step;
 358         }
 359 }
 360 #endif
 361
 362 /*
 363  * this is only called by cache_block_group, since we could have freed extents
 364  * we need to check the pinned_extents for any extents that can't be used yet
 365  * since their free space will be released as soon as the transaction commits.
 366  */
 367 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 368                        struct btrfs_fs_info *info, u64 start, u64 end)
 369 {
 370         u64 extent_start, extent_end, size, total_added = 0;
 371         int ret;
 372
 373         while (start < end) {
 374                 ret = find_first_extent_bit(info->pinned_extents, start,
 375                                             &extent_start, &extent_end,
 376                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 377                                             NULL);
 378                 if (ret)
 379                         break;
 380
 381                 if (extent_start <= start) {
 382                         start = extent_end + 1;
 383                 } else if (extent_start > start && extent_start < end) {
 384                         size = extent_start - start;
 385                         total_added += size;
 386                         ret = btrfs_add_free_space(block_group, start,
 387                                                    size);
 388                         BUG_ON(ret); /* -ENOMEM or logic error */
 389                         start = extent_end + 1;
 390                 } else {
 391                         break;
 392                 }
 393         }
 394
 395         if (start < end) {
 396                 size = end - start;
 397                 total_added += size;
 398                 ret = btrfs_add_free_space(block_group, start, size);
 399                 BUG_ON(ret); /* -ENOMEM or logic error */
 400         }
 401
 402         return total_added;
 403 }
 404
 405 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 406 {
 407         struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
 408         struct btrfs_fs_info *fs_info = block_group->fs_info;
 409         struct btrfs_root *extent_root = fs_info->extent_root;
 410         struct btrfs_path *path;
 411         struct extent_buffer *leaf;
 412         struct btrfs_key key;
 413         u64 total_found = 0;
 414         u64 last = 0;
 415         u32 nritems;
 416         int ret;
 417         bool wakeup = true;
 418
 419         path = btrfs_alloc_path();
 420         if (!path)
 421                 return -ENOMEM;
 422
 423         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 424
 425 #ifdef CONFIG_BTRFS_DEBUG
 426         /*
 427          * If we're fragmenting we don't want to make anybody think we can
 428          * allocate from this block group until we've had a chance to fragment
 429          * the free space.
 430          */
 431         if (btrfs_should_fragment_free_space(block_group))
 432                 wakeup = false;
 433 #endif
 434         /*
 435          * We don't want to deadlock with somebody trying to allocate a new
 436          * extent for the extent root while also trying to search the extent
 437          * root to add free space.  So we skip locking and search the commit
 438          * root, since its read-only
 439          */
 440         path->skip_locking = 1;
 441         path->search_commit_root = 1;
 442         path->reada = READA_FORWARD;
 443
 444         key.objectid = last;
 445         key.offset = 0;
 446         key.type = BTRFS_EXTENT_ITEM_KEY;
 447
 448 next:
 449         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 450         if (ret < 0)
 451                 goto out;
 452
 453         leaf = path->nodes[0];
 454         nritems = btrfs_header_nritems(leaf);
 455
 456         while (1) {
 457                 if (btrfs_fs_closing(fs_info) > 1) {
 458                         last = (u64)-1;
 459                         break;
 460                 }
 461
 462                 if (path->slots[0] < nritems) {
 463                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 464                 } else {
 465                         ret = find_next_key(path, 0, &key);
 466                         if (ret)
 467                                 break;
 468
 469                         if (need_resched() ||
 470                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 471                                 if (wakeup)
 472                                         caching_ctl->progress = last;
 473                                 btrfs_release_path(path);
 474                                 up_read(&fs_info->commit_root_sem);
 475                                 mutex_unlock(&caching_ctl->mutex);
 476                                 cond_resched();
 477                                 mutex_lock(&caching_ctl->mutex);
 478                                 down_read(&fs_info->commit_root_sem);
 479                                 goto next;
 480                         }
 481
 482                         ret = btrfs_next_leaf(extent_root, path);
 483                         if (ret < 0)
 484                                 goto out;
 485                         if (ret)
 486                                 break;
 487                         leaf = path->nodes[0];
 488                         nritems = btrfs_header_nritems(leaf);
 489                         continue;
 490                 }
 491
 492                 if (key.objectid < last) {
 493                         key.objectid = last;
 494                         key.offset = 0;
 495                         key.type = BTRFS_EXTENT_ITEM_KEY;
 496
 497                         if (wakeup)
 498                                 caching_ctl->progress = last;
 499                         btrfs_release_path(path);
 500                         goto next;
 501                 }
 502
 503                 if (key.objectid < block_group->key.objectid) {
 504                         path->slots[0]++;
 505                         continue;
 506                 }
 507
 508                 if (key.objectid >= block_group->key.objectid +
 509                     block_group->key.offset)
 510                         break;
 511
 512                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 513                     key.type == BTRFS_METADATA_ITEM_KEY) {
 514                         total_found += add_new_free_space(block_group,
 515                                                           fs_info, last,
 516                                                           key.objectid);
 517                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 518                                 last = key.objectid +
 519                                         fs_info->nodesize;
 520                         else
 521                                 last = key.objectid + key.offset;
 522
 523                         if (total_found > CACHING_CTL_WAKE_UP) {
 524                                 total_found = 0;
 525                                 if (wakeup)
 526                                         wake_up(&caching_ctl->wait);
 527                         }
 528                 }
 529                 path->slots[0]++;
 530         }
 531         ret = 0;
 532
 533         total_found += add_new_free_space(block_group, fs_info, last,
 534                                           block_group->key.objectid +
 535                                           block_group->key.offset);
 536         caching_ctl->progress = (u64)-1;
 537
 538 out:
 539         btrfs_free_path(path);
 540         return ret;
 541 }
 542
 543 static noinline void caching_thread(struct btrfs_work *work)
 544 {
 545         struct btrfs_block_group_cache *block_group;
 546         struct btrfs_fs_info *fs_info;
 547         struct btrfs_caching_control *caching_ctl;
 548         struct btrfs_root *extent_root;
 549         int ret;
 550
 551         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 552         block_group = caching_ctl->block_group;
 553         fs_info = block_group->fs_info;
 554         extent_root = fs_info->extent_root;
 555
 556         mutex_lock(&caching_ctl->mutex);
 557         down_read(&fs_info->commit_root_sem);
 558
 559         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 560                 ret = load_free_space_tree(caching_ctl);
 561         else
 562                 ret = load_extent_tree_free(caching_ctl);
 563
 564         spin_lock(&block_group->lock);
 565         block_group->caching_ctl = NULL;
 566         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 567         spin_unlock(&block_group->lock);
 568
 569 #ifdef CONFIG_BTRFS_DEBUG
 570         if (btrfs_should_fragment_free_space(block_group)) {
 571                 u64 bytes_used;
 572
 573                 spin_lock(&block_group->space_info->lock);
 574                 spin_lock(&block_group->lock);
 575                 bytes_used = block_group->key.offset -
 576                         btrfs_block_group_used(&block_group->item);
 577                 block_group->space_info->bytes_used += bytes_used >> 1;
 578                 spin_unlock(&block_group->lock);
 579                 spin_unlock(&block_group->space_info->lock);
 580                 fragment_free_space(block_group);
 581         }
 582 #endif
 583
 584         caching_ctl->progress = (u64)-1;
 585
 586         up_read(&fs_info->commit_root_sem);
 587         free_excluded_extents(fs_info, block_group);
 588         mutex_unlock(&caching_ctl->mutex);
 589
 590         wake_up(&caching_ctl->wait);
 591
 592         put_caching_control(caching_ctl);
 593         btrfs_put_block_group(block_group);
 594 }
 595
 596 static int cache_block_group(struct btrfs_block_group_cache *cache,
 597                              int load_cache_only)
 598 {
 599         DEFINE_WAIT(wait);
 600         struct btrfs_fs_info *fs_info = cache->fs_info;
 601         struct btrfs_caching_control *caching_ctl;
 602         int ret = 0;
 603
 604         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 605         if (!caching_ctl)
 606                 return -ENOMEM;
 607
 608         INIT_LIST_HEAD(&caching_ctl->list);
 609         mutex_init(&caching_ctl->mutex);
 610         init_waitqueue_head(&caching_ctl->wait);
 611         caching_ctl->block_group = cache;
 612         caching_ctl->progress = cache->key.objectid;
 613         refcount_set(&caching_ctl->count, 1);
 614         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 615                         caching_thread, NULL, NULL);
 616
 617         spin_lock(&cache->lock);
 618         /*
 619          * This should be a rare occasion, but this could happen I think in the
 620          * case where one thread starts to load the space cache info, and then
 621          * some other thread starts a transaction commit which tries to do an
 622          * allocation while the other thread is still loading the space cache
 623          * info.  The previous loop should have kept us from choosing this block
 624          * group, but if we've moved to the state where we will wait on caching
 625          * block groups we need to first check if we're doing a fast load here,
 626          * so we can wait for it to finish, otherwise we could end up allocating
 627          * from a block group who's cache gets evicted for one reason or
 628          * another.
 629          */
 630         while (cache->cached == BTRFS_CACHE_FAST) {
 631                 struct btrfs_caching_control *ctl;
 632
 633                 ctl = cache->caching_ctl;
 634                 refcount_inc(&ctl->count);
 635                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 636                 spin_unlock(&cache->lock);
 637
 638                 schedule();
 639
 640                 finish_wait(&ctl->wait, &wait);
 641                 put_caching_control(ctl);
 642                 spin_lock(&cache->lock);
 643         }
 644
 645         if (cache->cached != BTRFS_CACHE_NO) {
 646                 spin_unlock(&cache->lock);
 647                 kfree(caching_ctl);
 648                 return 0;
 649         }
 650         WARN_ON(cache->caching_ctl);
 651         cache->caching_ctl = caching_ctl;
 652         cache->cached = BTRFS_CACHE_FAST;
 653         spin_unlock(&cache->lock);
 654
 655         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 656                 mutex_lock(&caching_ctl->mutex);
 657                 ret = load_free_space_cache(fs_info, cache);
 658
 659                 spin_lock(&cache->lock);
 660                 if (ret == 1) {
 661                         cache->caching_ctl = NULL;
 662                         cache->cached = BTRFS_CACHE_FINISHED;
 663                         cache->last_byte_to_unpin = (u64)-1;
 664                         caching_ctl->progress = (u64)-1;
 665                 } else {
 666                         if (load_cache_only) {
 667                                 cache->caching_ctl = NULL;
 668                                 cache->cached = BTRFS_CACHE_NO;
 669                         } else {
 670                                 cache->cached = BTRFS_CACHE_STARTED;
 671                                 cache->has_caching_ctl = 1;
 672                         }
 673                 }
 674                 spin_unlock(&cache->lock);
 675 #ifdef CONFIG_BTRFS_DEBUG
 676                 if (ret == 1 &&
 677                     btrfs_should_fragment_free_space(cache)) {
 678                         u64 bytes_used;
 679
 680                         spin_lock(&cache->space_info->lock);
 681                         spin_lock(&cache->lock);
 682                         bytes_used = cache->key.offset -
 683                                 btrfs_block_group_used(&cache->item);
 684                         cache->space_info->bytes_used += bytes_used >> 1;
 685                         spin_unlock(&cache->lock);
 686                         spin_unlock(&cache->space_info->lock);
 687                         fragment_free_space(cache);
 688                 }
 689 #endif
 690                 mutex_unlock(&caching_ctl->mutex);
 691
 692                 wake_up(&caching_ctl->wait);
 693                 if (ret == 1) {
 694                         put_caching_control(caching_ctl);
 695                         free_excluded_extents(fs_info, cache);
 696                         return 0;
 697                 }
 698         } else {
 699                 /*
 700                  * We're either using the free space tree or no caching at all.
 701                  * Set cached to the appropriate value and wakeup any waiters.
 702                  */
 703                 spin_lock(&cache->lock);
 704                 if (load_cache_only) {
 705                         cache->caching_ctl = NULL;
 706                         cache->cached = BTRFS_CACHE_NO;
 707                 } else {
 708                         cache->cached = BTRFS_CACHE_STARTED;
 709                         cache->has_caching_ctl = 1;
 710                 }
 711                 spin_unlock(&cache->lock);
 712                 wake_up(&caching_ctl->wait);
 713         }
 714
 715         if (load_cache_only) {
 716                 put_caching_control(caching_ctl);
 717                 return 0;
 718         }
 719
 720         down_write(&fs_info->commit_root_sem);
 721         refcount_inc(&caching_ctl->count);
 722         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 723         up_write(&fs_info->commit_root_sem);
 724
 725         btrfs_get_block_group(cache);
 726
 727         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 728
 729         return ret;
 730 }
 731
 732 /*
 733  * return the block group that starts at or after bytenr
 734  */
 735 static struct btrfs_block_group_cache *
 736 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 737 {
 738         return block_group_cache_tree_search(info, bytenr, 0);
 739 }
 740
 741 /*
 742  * return the block group that contains the given bytenr
 743  */
 744 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 745                                                  struct btrfs_fs_info *info,
 746                                                  u64 bytenr)
 747 {
 748         return block_group_cache_tree_search(info, bytenr, 1);
 749 }
 750
 751 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 752                                                   u64 flags)
 753 {
 754         struct list_head *head = &info->space_info;
 755         struct btrfs_space_info *found;
 756
 757         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 758
 759         rcu_read_lock();
 760         list_for_each_entry_rcu(found, head, list) {
 761                 if (found->flags & flags) {
 762                         rcu_read_unlock();
 763                         return found;
 764                 }
 765         }
 766         rcu_read_unlock();
 767         return NULL;
 768 }
 769
 770 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, s64 num_bytes,
 771                              u64 owner, u64 root_objectid)
 772 {
 773         struct btrfs_space_info *space_info;
 774         u64 flags;
 775
 776         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 777                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
 778                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
 779                 else
 780                         flags = BTRFS_BLOCK_GROUP_METADATA;
 781         } else {
 782                 flags = BTRFS_BLOCK_GROUP_DATA;
 783         }
 784
 785         space_info = __find_space_info(fs_info, flags);
 786         ASSERT(space_info);
 787         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
 788 }
 789
 790 /*
 791  * after adding space to the filesystem, we need to clear the full flags
 792  * on all the space infos.
 793  */
 794 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 795 {
 796         struct list_head *head = &info->space_info;
 797         struct btrfs_space_info *found;
 798
 799         rcu_read_lock();
 800         list_for_each_entry_rcu(found, head, list)
 801                 found->full = 0;
 802         rcu_read_unlock();
 803 }
 804
 805 /* simple helper to search for an existing data extent at a given offset */
 806 int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
 807 {
 808         int ret;
 809         struct btrfs_key key;
 810         struct btrfs_path *path;
 811
 812         path = btrfs_alloc_path();
 813         if (!path)
 814                 return -ENOMEM;
 815
 816         key.objectid = start;
 817         key.offset = len;
 818         key.type = BTRFS_EXTENT_ITEM_KEY;
 819         ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 820         btrfs_free_path(path);
 821         return ret;
 822 }
 823
 824 /*
 825  * helper function to lookup reference count and flags of a tree block.
 826  *
 827  * the head node for delayed ref is used to store the sum of all the
 828  * reference count modifications queued up in the rbtree. the head
 829  * node may also store the extent flags to set. This way you can check
 830  * to see what the reference count and extent flags would be if all of
 831  * the delayed refs are not processed.
 832  */
 833 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 834                              struct btrfs_fs_info *fs_info, u64 bytenr,
 835                              u64 offset, int metadata, u64 *refs, u64 *flags)
 836 {
 837         struct btrfs_delayed_ref_head *head;
 838         struct btrfs_delayed_ref_root *delayed_refs;
 839         struct btrfs_path *path;
 840         struct btrfs_extent_item *ei;
 841         struct extent_buffer *leaf;
 842         struct btrfs_key key;
 843         u32 item_size;
 844         u64 num_refs;
 845         u64 extent_flags;
 846         int ret;
 847
 848         /*
 849          * If we don't have skinny metadata, don't bother doing anything
 850          * different
 851          */
 852         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 853                 offset = fs_info->nodesize;
 854                 metadata = 0;
 855         }
 856
 857         path = btrfs_alloc_path();
 858         if (!path)
 859                 return -ENOMEM;
 860
 861         if (!trans) {
 862                 path->skip_locking = 1;
 863                 path->search_commit_root = 1;
 864         }
 865
 866 search_again:
 867         key.objectid = bytenr;
 868         key.offset = offset;
 869         if (metadata)
 870                 key.type = BTRFS_METADATA_ITEM_KEY;
 871         else
 872                 key.type = BTRFS_EXTENT_ITEM_KEY;
 873
 874         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 875         if (ret < 0)
 876                 goto out_free;
 877
 878         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 879                 if (path->slots[0]) {
 880                         path->slots[0]--;
 881                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 882                                               path->slots[0]);
 883                         if (key.objectid == bytenr &&
 884                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 885                             key.offset == fs_info->nodesize)
 886                                 ret = 0;
 887                 }
 888         }
 889
 890         if (ret == 0) {
 891                 leaf = path->nodes[0];
 892                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 893                 if (item_size >= sizeof(*ei)) {
 894                         ei = btrfs_item_ptr(leaf, path->slots[0],
 895                                             struct btrfs_extent_item);
 896                         num_refs = btrfs_extent_refs(leaf, ei);
 897                         extent_flags = btrfs_extent_flags(leaf, ei);
 898                 } else {
 899 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 900                         struct btrfs_extent_item_v0 *ei0;
 901                         BUG_ON(item_size != sizeof(*ei0));
 902                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 903                                              struct btrfs_extent_item_v0);
 904                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 905                         /* FIXME: this isn't correct for data */
 906                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 907 #else
 908                         BUG();
 909 #endif
 910                 }
 911                 BUG_ON(num_refs == 0);
 912         } else {
 913                 num_refs = 0;
 914                 extent_flags = 0;
 915                 ret = 0;
 916         }
 917
 918         if (!trans)
 919                 goto out;
 920
 921         delayed_refs = &trans->transaction->delayed_refs;
 922         spin_lock(&delayed_refs->lock);
 923         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 924         if (head) {
 925                 if (!mutex_trylock(&head->mutex)) {
 926                         refcount_inc(&head->node.refs);
 927                         spin_unlock(&delayed_refs->lock);
 928
 929                         btrfs_release_path(path);
 930
 931                         /*
 932                          * Mutex was contended, block until it's released and try
 933                          * again
 934                          */
 935                         mutex_lock(&head->mutex);
 936                         mutex_unlock(&head->mutex);
 937                         btrfs_put_delayed_ref(&head->node);
 938                         goto search_again;
 939                 }
 940                 spin_lock(&head->lock);
 941                 if (head->extent_op && head->extent_op->update_flags)
 942                         extent_flags |= head->extent_op->flags_to_set;
 943                 else
 944                         BUG_ON(num_refs == 0);
 945
 946                 num_refs += head->node.ref_mod;
 947                 spin_unlock(&head->lock);
 948                 mutex_unlock(&head->mutex);
 949         }
 950         spin_unlock(&delayed_refs->lock);
 951 out:
 952         WARN_ON(num_refs == 0);
 953         if (refs)
 954                 *refs = num_refs;
 955         if (flags)
 956                 *flags = extent_flags;
 957 out_free:
 958         btrfs_free_path(path);
 959         return ret;
 960 }
 961
 962 /*
 963  * Back reference rules.  Back refs have three main goals:
 964  *
 965  * 1) differentiate between all holders of references to an extent so that
 966  *    when a reference is dropped we can make sure it was a valid reference
 967  *    before freeing the extent.
 968  *
 969  * 2) Provide enough information to quickly find the holders of an extent
 970  *    if we notice a given block is corrupted or bad.
 971  *
 972  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 973  *    maintenance.  This is actually the same as #2, but with a slightly
 974  *    different use case.
 975  *
 976  * There are two kinds of back refs. The implicit back refs is optimized
 977  * for pointers in non-shared tree blocks. For a given pointer in a block,
 978  * back refs of this kind provide information about the block's owner tree
 979  * and the pointer's key. These information allow us to find the block by
 980  * b-tree searching. The full back refs is for pointers in tree blocks not
 981  * referenced by their owner trees. The location of tree block is recorded
 982  * in the back refs. Actually the full back refs is generic, and can be
 983  * used in all cases the implicit back refs is used. The major shortcoming
 984  * of the full back refs is its overhead. Every time a tree block gets
 985  * COWed, we have to update back refs entry for all pointers in it.
 986  *
 987  * For a newly allocated tree block, we use implicit back refs for
 988  * pointers in it. This means most tree related operations only involve
 989  * implicit back refs. For a tree block created in old transaction, the
 990  * only way to drop a reference to it is COW it. So we can detect the
 991  * event that tree block loses its owner tree's reference and do the
 992  * back refs conversion.
 993  *
 994  * When a tree block is COWed through a tree, there are four cases:
 995  *
 996  * The reference count of the block is one and the tree is the block's
 997  * owner tree. Nothing to do in this case.
 998  *
 999  * The reference count of the block is one and the tree is not the
1000  * block's owner tree. In this case, full back refs is used for pointers
1001  * in the block. Remove these full back refs, add implicit back refs for
1002  * every pointers in the new block.
1003  *
1004  * The reference count of the block is greater than one and the tree is
1005  * the block's owner tree. In this case, implicit back refs is used for
1006  * pointers in the block. Add full back refs for every pointers in the
1007  * block, increase lower level extents' reference counts. The original
1008  * implicit back refs are entailed to the new block.
1009  *
1010  * The reference count of the block is greater than one and the tree is
1011  * not the block's owner tree. Add implicit back refs for every pointer in
1012  * the new block, increase lower level extents' reference count.
1013  *
1014  * Back Reference Key composing:
1015  *
1016  * The key objectid corresponds to the first byte in the extent,
1017  * The key type is used to differentiate between types of back refs.
1018  * There are different meanings of the key offset for different types
1019  * of back refs.
1020  *
1021  * File extents can be referenced by:
1022  *
1023  * - multiple snapshots, subvolumes, or different generations in one subvol
1024  * - different files inside a single subvolume
1025  * - different offsets inside a file (bookend extents in file.c)
1026  *
1027  * The extent ref structure for the implicit back refs has fields for:
1028  *
1029  * - Objectid of the subvolume root
1030  * - objectid of the file holding the reference
1031  * - original offset in the file
1032  * - how many bookend extents
1033  *
1034  * The key offset for the implicit back refs is hash of the first
1035  * three fields.
1036  *
1037  * The extent ref structure for the full back refs has field for:
1038  *
1039  * - number of pointers in the tree leaf
1040  *
1041  * The key offset for the implicit back refs is the first byte of
1042  * the tree leaf
1043  *
1044  * When a file extent is allocated, The implicit back refs is used.
1045  * the fields are filled in:
1046  *
1047  *     (root_key.objectid, inode objectid, offset in file, 1)
1048  *
1049  * When a file extent is removed file truncation, we find the
1050  * corresponding implicit back refs and check the following fields:
1051  *
1052  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1053  *
1054  * Btree extents can be referenced by:
1055  *
1056  * - Different subvolumes
1057  *
1058  * Both the implicit back refs and the full back refs for tree blocks
1059  * only consist of key. The key offset for the implicit back refs is
1060  * objectid of block's owner tree. The key offset for the full back refs
1061  * is the first byte of parent block.
1062  *
1063  * When implicit back refs is used, information about the lowest key and
1064  * level of the tree block are required. These information are stored in
1065  * tree block info structure.
1066  */
1067
1068 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1069 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1070                                   struct btrfs_fs_info *fs_info,
1071                                   struct btrfs_path *path,
1072                                   u64 owner, u32 extra_size)
1073 {
1074         struct btrfs_root *root = fs_info->extent_root;
1075         struct btrfs_extent_item *item;
1076         struct btrfs_extent_item_v0 *ei0;
1077         struct btrfs_extent_ref_v0 *ref0;
1078         struct btrfs_tree_block_info *bi;
1079         struct extent_buffer *leaf;
1080         struct btrfs_key key;
1081         struct btrfs_key found_key;
1082         u32 new_size = sizeof(*item);
1083         u64 refs;
1084         int ret;
1085
1086         leaf = path->nodes[0];
1087         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1088
1089         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1090         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1091                              struct btrfs_extent_item_v0);
1092         refs = btrfs_extent_refs_v0(leaf, ei0);
1093
1094         if (owner == (u64)-1) {
1095                 while (1) {
1096                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1097                                 ret = btrfs_next_leaf(root, path);
1098                                 if (ret < 0)
1099                                         return ret;
1100                                 BUG_ON(ret > 0); /* Corruption */
1101                                 leaf = path->nodes[0];
1102                         }
1103                         btrfs_item_key_to_cpu(leaf, &found_key,
1104                                               path->slots[0]);
1105                         BUG_ON(key.objectid != found_key.objectid);
1106                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1107                                 path->slots[0]++;
1108                                 continue;
1109                         }
1110                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1111                                               struct btrfs_extent_ref_v0);
1112                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1113                         break;
1114                 }
1115         }
1116         btrfs_release_path(path);
1117
1118         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1119                 new_size += sizeof(*bi);
1120
1121         new_size -= sizeof(*ei0);
1122         ret = btrfs_search_slot(trans, root, &key, path,
1123                                 new_size + extra_size, 1);
1124         if (ret < 0)
1125                 return ret;
1126         BUG_ON(ret); /* Corruption */
1127
1128         btrfs_extend_item(fs_info, path, new_size);
1129
1130         leaf = path->nodes[0];
1131         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1132         btrfs_set_extent_refs(leaf, item, refs);
1133         /* FIXME: get real generation */
1134         btrfs_set_extent_generation(leaf, item, 0);
1135         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1136                 btrfs_set_extent_flags(leaf, item,
1137                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1138                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1139                 bi = (struct btrfs_tree_block_info *)(item + 1);
1140                 /* FIXME: get first key of the block */
1141                 memzero_extent_buffer(leaf, (unsigned long)bi, sizeof(*bi));
1142                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1143         } else {
1144                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1145         }
1146         btrfs_mark_buffer_dirty(leaf);
1147         return 0;
1148 }
1149 #endif
1150
1151 /*
1152  * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
1153  * is_data == BTRFS_REF_TYPE_DATA, data type is requried,
1154  * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
1155  */
1156 int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
1157                                      struct btrfs_extent_inline_ref *iref,
1158                                      enum btrfs_inline_ref_type is_data)
1159 {
1160         int type = btrfs_extent_inline_ref_type(eb, iref);
1161         u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
1162
1163         if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1164             type == BTRFS_SHARED_BLOCK_REF_KEY ||
1165             type == BTRFS_SHARED_DATA_REF_KEY ||
1166             type == BTRFS_EXTENT_DATA_REF_KEY) {
1167                 if (is_data == BTRFS_REF_TYPE_BLOCK) {
1168                         if (type == BTRFS_TREE_BLOCK_REF_KEY)
1169                                 return type;
1170                         if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1171                                 ASSERT(eb->fs_info);
1172                                 /*
1173                                  * Every shared one has parent tree
1174                                  * block, which must be aligned to
1175                                  * nodesize.
1176                                  */
1177                                 if (offset &&
1178                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1179                                         return type;
1180                         }
1181                 } else if (is_data == BTRFS_REF_TYPE_DATA) {
1182                         if (type == BTRFS_EXTENT_DATA_REF_KEY)
1183                                 return type;
1184                         if (type == BTRFS_SHARED_DATA_REF_KEY) {
1185                                 ASSERT(eb->fs_info);
1186                                 /*
1187                                  * Every shared one has parent tree
1188                                  * block, which must be aligned to
1189                                  * nodesize.
1190                                  */
1191                                 if (offset &&
1192                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1193                                         return type;
1194                         }
1195                 } else {
1196                         ASSERT(is_data == BTRFS_REF_TYPE_ANY);
1197                         return type;
1198                 }
1199         }
1200
1201         btrfs_print_leaf((struct extent_buffer *)eb);
1202         btrfs_err(eb->fs_info, "eb %llu invalid extent inline ref type %d",
1203                   eb->start, type);
1204         WARN_ON(1);
1205
1206         return BTRFS_REF_TYPE_INVALID;
1207 }
1208
1209 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1210 {
1211         u32 high_crc = ~(u32)0;
1212         u32 low_crc = ~(u32)0;
1213         __le64 lenum;
1214
1215         lenum = cpu_to_le64(root_objectid);
1216         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1217         lenum = cpu_to_le64(owner);
1218         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1219         lenum = cpu_to_le64(offset);
1220         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1221
1222         return ((u64)high_crc << 31) ^ (u64)low_crc;
1223 }
1224
1225 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1226                                      struct btrfs_extent_data_ref *ref)
1227 {
1228         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1229                                     btrfs_extent_data_ref_objectid(leaf, ref),
1230                                     btrfs_extent_data_ref_offset(leaf, ref));
1231 }
1232
1233 static int match_extent_data_ref(struct extent_buffer *leaf,
1234                                  struct btrfs_extent_data_ref *ref,
1235                                  u64 root_objectid, u64 owner, u64 offset)
1236 {
1237         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1238             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1239             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1240                 return 0;
1241         return 1;
1242 }
1243
1244 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1245                                            struct btrfs_fs_info *fs_info,
1246                                            struct btrfs_path *path,
1247                                            u64 bytenr, u64 parent,
1248                                            u64 root_objectid,
1249                                            u64 owner, u64 offset)
1250 {
1251         struct btrfs_root *root = fs_info->extent_root;
1252         struct btrfs_key key;
1253         struct btrfs_extent_data_ref *ref;
1254         struct extent_buffer *leaf;
1255         u32 nritems;
1256         int ret;
1257         int recow;
1258         int err = -ENOENT;
1259
1260         key.objectid = bytenr;
1261         if (parent) {
1262                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1263                 key.offset = parent;
1264         } else {
1265                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1266                 key.offset = hash_extent_data_ref(root_objectid,
1267                                                   owner, offset);
1268         }
1269 again:
1270         recow = 0;
1271         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1272         if (ret < 0) {
1273                 err = ret;
1274                 goto fail;
1275         }
1276
1277         if (parent) {
1278                 if (!ret)
1279                         return 0;
1280 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1281                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1282                 btrfs_release_path(path);
1283                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1284                 if (ret < 0) {
1285                         err = ret;
1286                         goto fail;
1287                 }
1288                 if (!ret)
1289                         return 0;
1290 #endif
1291                 goto fail;
1292         }
1293
1294         leaf = path->nodes[0];
1295         nritems = btrfs_header_nritems(leaf);
1296         while (1) {
1297                 if (path->slots[0] >= nritems) {
1298                         ret = btrfs_next_leaf(root, path);
1299                         if (ret < 0)
1300                                 err = ret;
1301                         if (ret)
1302                                 goto fail;
1303
1304                         leaf = path->nodes[0];
1305                         nritems = btrfs_header_nritems(leaf);
1306                         recow = 1;
1307                 }
1308
1309                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1310                 if (key.objectid != bytenr ||
1311                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1312                         goto fail;
1313
1314                 ref = btrfs_item_ptr(leaf, path->slots[0],
1315                                      struct btrfs_extent_data_ref);
1316
1317                 if (match_extent_data_ref(leaf, ref, root_objectid,
1318                                           owner, offset)) {
1319                         if (recow) {
1320                                 btrfs_release_path(path);
1321                                 goto again;
1322                         }
1323                         err = 0;
1324                         break;
1325                 }
1326                 path->slots[0]++;
1327         }
1328 fail:
1329         return err;
1330 }
1331
1332 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1333                                            struct btrfs_fs_info *fs_info,
1334                                            struct btrfs_path *path,
1335                                            u64 bytenr, u64 parent,
1336                                            u64 root_objectid, u64 owner,
1337                                            u64 offset, int refs_to_add)
1338 {
1339         struct btrfs_root *root = fs_info->extent_root;
1340         struct btrfs_key key;
1341         struct extent_buffer *leaf;
1342         u32 size;
1343         u32 num_refs;
1344         int ret;
1345
1346         key.objectid = bytenr;
1347         if (parent) {
1348                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1349                 key.offset = parent;
1350                 size = sizeof(struct btrfs_shared_data_ref);
1351         } else {
1352                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1353                 key.offset = hash_extent_data_ref(root_objectid,
1354                                                   owner, offset);
1355                 size = sizeof(struct btrfs_extent_data_ref);
1356         }
1357
1358         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1359         if (ret && ret != -EEXIST)
1360                 goto fail;
1361
1362         leaf = path->nodes[0];
1363         if (parent) {
1364                 struct btrfs_shared_data_ref *ref;
1365                 ref = btrfs_item_ptr(leaf, path->slots[0],
1366                                      struct btrfs_shared_data_ref);
1367                 if (ret == 0) {
1368                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1369                 } else {
1370                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1371                         num_refs += refs_to_add;
1372                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1373                 }
1374         } else {
1375                 struct btrfs_extent_data_ref *ref;
1376                 while (ret == -EEXIST) {
1377                         ref = btrfs_item_ptr(leaf, path->slots[0],
1378                                              struct btrfs_extent_data_ref);
1379                         if (match_extent_data_ref(leaf, ref, root_objectid,
1380                                                   owner, offset))
1381                                 break;
1382                         btrfs_release_path(path);
1383                         key.offset++;
1384                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1385                                                       size);
1386                         if (ret && ret != -EEXIST)
1387                                 goto fail;
1388
1389                         leaf = path->nodes[0];
1390                 }
1391                 ref = btrfs_item_ptr(leaf, path->slots[0],
1392                                      struct btrfs_extent_data_ref);
1393                 if (ret == 0) {
1394                         btrfs_set_extent_data_ref_root(leaf, ref,
1395                                                        root_objectid);
1396                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1397                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1398                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1399                 } else {
1400                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1401                         num_refs += refs_to_add;
1402                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1403                 }
1404         }
1405         btrfs_mark_buffer_dirty(leaf);
1406         ret = 0;
1407 fail:
1408         btrfs_release_path(path);
1409         return ret;
1410 }
1411
1412 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1413                                            struct btrfs_fs_info *fs_info,
1414                                            struct btrfs_path *path,
1415                                            int refs_to_drop, int *last_ref)
1416 {
1417         struct btrfs_key key;
1418         struct btrfs_extent_data_ref *ref1 = NULL;
1419         struct btrfs_shared_data_ref *ref2 = NULL;
1420         struct extent_buffer *leaf;
1421         u32 num_refs = 0;
1422         int ret = 0;
1423
1424         leaf = path->nodes[0];
1425         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1426
1427         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1428                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1429                                       struct btrfs_extent_data_ref);
1430                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1431         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1432                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1433                                       struct btrfs_shared_data_ref);
1434                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1435 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1436         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1437                 struct btrfs_extent_ref_v0 *ref0;
1438                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1439                                       struct btrfs_extent_ref_v0);
1440                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1441 #endif
1442         } else {
1443                 BUG();
1444         }
1445
1446         BUG_ON(num_refs < refs_to_drop);
1447         num_refs -= refs_to_drop;
1448
1449         if (num_refs == 0) {
1450                 ret = btrfs_del_item(trans, fs_info->extent_root, path);
1451                 *last_ref = 1;
1452         } else {
1453                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1454                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1455                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1456                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1457 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1458                 else {
1459                         struct btrfs_extent_ref_v0 *ref0;
1460                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1461                                         struct btrfs_extent_ref_v0);
1462                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1463                 }
1464 #endif
1465                 btrfs_mark_buffer_dirty(leaf);
1466         }
1467         return ret;
1468 }
1469
1470 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1471                                           struct btrfs_extent_inline_ref *iref)
1472 {
1473         struct btrfs_key key;
1474         struct extent_buffer *leaf;
1475         struct btrfs_extent_data_ref *ref1;
1476         struct btrfs_shared_data_ref *ref2;
1477         u32 num_refs = 0;
1478         int type;
1479
1480         leaf = path->nodes[0];
1481         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1482         if (iref) {
1483                 /*
1484                  * If type is invalid, we should have bailed out earlier than
1485                  * this call.
1486                  */
1487                 type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
1488                 ASSERT(type != BTRFS_REF_TYPE_INVALID);
1489                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1490                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1491                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1492                 } else {
1493                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1494                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1495                 }
1496         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1497                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1498                                       struct btrfs_extent_data_ref);
1499                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1500         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1501                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1502                                       struct btrfs_shared_data_ref);
1503                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1504 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1505         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1506                 struct btrfs_extent_ref_v0 *ref0;
1507                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1508                                       struct btrfs_extent_ref_v0);
1509                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1510 #endif
1511         } else {
1512                 WARN_ON(1);
1513         }
1514         return num_refs;
1515 }
1516
1517 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1518                                           struct btrfs_fs_info *fs_info,
1519                                           struct btrfs_path *path,
1520                                           u64 bytenr, u64 parent,
1521                                           u64 root_objectid)
1522 {
1523         struct btrfs_root *root = fs_info->extent_root;
1524         struct btrfs_key key;
1525         int ret;
1526
1527         key.objectid = bytenr;
1528         if (parent) {
1529                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1530                 key.offset = parent;
1531         } else {
1532                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1533                 key.offset = root_objectid;
1534         }
1535
1536         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1537         if (ret > 0)
1538                 ret = -ENOENT;
1539 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1540         if (ret == -ENOENT && parent) {
1541                 btrfs_release_path(path);
1542                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1543                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1544                 if (ret > 0)
1545                         ret = -ENOENT;
1546         }
1547 #endif
1548         return ret;
1549 }
1550
1551 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1552                                           struct btrfs_fs_info *fs_info,
1553                                           struct btrfs_path *path,
1554                                           u64 bytenr, u64 parent,
1555                                           u64 root_objectid)
1556 {
1557         struct btrfs_key key;
1558         int ret;
1559
1560         key.objectid = bytenr;
1561         if (parent) {
1562                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1563                 key.offset = parent;
1564         } else {
1565                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1566                 key.offset = root_objectid;
1567         }
1568
1569         ret = btrfs_insert_empty_item(trans, fs_info->extent_root,
1570                                       path, &key, 0);
1571         btrfs_release_path(path);
1572         return ret;
1573 }
1574
1575 static inline int extent_ref_type(u64 parent, u64 owner)
1576 {
1577         int type;
1578         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1579                 if (parent > 0)
1580                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1581                 else
1582                         type = BTRFS_TREE_BLOCK_REF_KEY;
1583         } else {
1584                 if (parent > 0)
1585                         type = BTRFS_SHARED_DATA_REF_KEY;
1586                 else
1587                         type = BTRFS_EXTENT_DATA_REF_KEY;
1588         }
1589         return type;
1590 }
1591
1592 static int find_next_key(struct btrfs_path *path, int level,
1593                          struct btrfs_key *key)
1594
1595 {
1596         for (; level < BTRFS_MAX_LEVEL; level++) {
1597                 if (!path->nodes[level])
1598                         break;
1599                 if (path->slots[level] + 1 >=
1600                     btrfs_header_nritems(path->nodes[level]))
1601                         continue;
1602                 if (level == 0)
1603                         btrfs_item_key_to_cpu(path->nodes[level], key,
1604                                               path->slots[level] + 1);
1605                 else
1606                         btrfs_node_key_to_cpu(path->nodes[level], key,
1607                                               path->slots[level] + 1);
1608                 return 0;
1609         }
1610         return 1;
1611 }
1612
1613 /*
1614  * look for inline back ref. if back ref is found, *ref_ret is set
1615  * to the address of inline back ref, and 0 is returned.
1616  *
1617  * if back ref isn't found, *ref_ret is set to the address where it
1618  * should be inserted, and -ENOENT is returned.
1619  *
1620  * if insert is true and there are too many inline back refs, the path
1621  * points to the extent item, and -EAGAIN is returned.
1622  *
1623  * NOTE: inline back refs are ordered in the same way that back ref
1624  *       items in the tree are ordered.
1625  */
1626 static noinline_for_stack
1627 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1628                                  struct btrfs_fs_info *fs_info,
1629                                  struct btrfs_path *path,
1630                                  struct btrfs_extent_inline_ref **ref_ret,
1631                                  u64 bytenr, u64 num_bytes,
1632                                  u64 parent, u64 root_objectid,
1633                                  u64 owner, u64 offset, int insert)
1634 {
1635         struct btrfs_root *root = fs_info->extent_root;
1636         struct btrfs_key key;
1637         struct extent_buffer *leaf;
1638         struct btrfs_extent_item *ei;
1639         struct btrfs_extent_inline_ref *iref;
1640         u64 flags;
1641         u64 item_size;
1642         unsigned long ptr;
1643         unsigned long end;
1644         int extra_size;
1645         int type;
1646         int want;
1647         int ret;
1648         int err = 0;
1649         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
1650         int needed;
1651
1652         key.objectid = bytenr;
1653         key.type = BTRFS_EXTENT_ITEM_KEY;
1654         key.offset = num_bytes;
1655
1656         want = extent_ref_type(parent, owner);
1657         if (insert) {
1658                 extra_size = btrfs_extent_inline_ref_size(want);
1659                 path->keep_locks = 1;
1660         } else
1661                 extra_size = -1;
1662
1663         /*
1664          * Owner is our parent level, so we can just add one to get the level
1665          * for the block we are interested in.
1666          */
1667         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1668                 key.type = BTRFS_METADATA_ITEM_KEY;
1669                 key.offset = owner;
1670         }
1671
1672 again:
1673         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1674         if (ret < 0) {
1675                 err = ret;
1676                 goto out;
1677         }
1678
1679         /*
1680          * We may be a newly converted file system which still has the old fat
1681          * extent entries for metadata, so try and see if we have one of those.
1682          */
1683         if (ret > 0 && skinny_metadata) {
1684                 skinny_metadata = false;
1685                 if (path->slots[0]) {
1686                         path->slots[0]--;
1687                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1688                                               path->slots[0]);
1689                         if (key.objectid == bytenr &&
1690                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1691                             key.offset == num_bytes)
1692                                 ret = 0;
1693                 }
1694                 if (ret) {
1695                         key.objectid = bytenr;
1696                         key.type = BTRFS_EXTENT_ITEM_KEY;
1697                         key.offset = num_bytes;
1698                         btrfs_release_path(path);
1699                         goto again;
1700                 }
1701         }
1702
1703         if (ret && !insert) {
1704                 err = -ENOENT;
1705                 goto out;
1706         } else if (WARN_ON(ret)) {
1707                 err = -EIO;
1708                 goto out;
1709         }
1710
1711         leaf = path->nodes[0];
1712         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1713 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1714         if (item_size < sizeof(*ei)) {
1715                 if (!insert) {
1716                         err = -ENOENT;
1717                         goto out;
1718                 }
1719                 ret = convert_extent_item_v0(trans, fs_info, path, owner,
1720                                              extra_size);
1721                 if (ret < 0) {
1722                         err = ret;
1723                         goto out;
1724                 }
1725                 leaf = path->nodes[0];
1726                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1727         }
1728 #endif
1729         BUG_ON(item_size < sizeof(*ei));
1730
1731         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1732         flags = btrfs_extent_flags(leaf, ei);
1733
1734         ptr = (unsigned long)(ei + 1);
1735         end = (unsigned long)ei + item_size;
1736
1737         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1738                 ptr += sizeof(struct btrfs_tree_block_info);
1739                 BUG_ON(ptr > end);
1740         }
1741
1742         if (owner >= BTRFS_FIRST_FREE_OBJECTID)
1743                 needed = BTRFS_REF_TYPE_DATA;
1744         else
1745                 needed = BTRFS_REF_TYPE_BLOCK;
1746
1747         err = -ENOENT;
1748         while (1) {
1749                 if (ptr >= end) {
1750                         WARN_ON(ptr > end);
1751                         break;
1752                 }
1753                 iref = (struct btrfs_extent_inline_ref *)ptr;
1754                 type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
1755                 if (type == BTRFS_REF_TYPE_INVALID) {
1756                         err = -EINVAL;
1757                         goto out;
1758                 }
1759
1760                 if (want < type)
1761                         break;
1762                 if (want > type) {
1763                         ptr += btrfs_extent_inline_ref_size(type);
1764                         continue;
1765                 }
1766
1767                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1768                         struct btrfs_extent_data_ref *dref;
1769                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1770                         if (match_extent_data_ref(leaf, dref, root_objectid,
1771                                                   owner, offset)) {
1772                                 err = 0;
1773                                 break;
1774                         }
1775                         if (hash_extent_data_ref_item(leaf, dref) <
1776                             hash_extent_data_ref(root_objectid, owner, offset))
1777                                 break;
1778                 } else {
1779                         u64 ref_offset;
1780                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1781                         if (parent > 0) {
1782                                 if (parent == ref_offset) {
1783                                         err = 0;
1784                                         break;
1785                                 }
1786                                 if (ref_offset < parent)
1787                                         break;
1788                         } else {
1789                                 if (root_objectid == ref_offset) {
1790                                         err = 0;
1791                                         break;
1792                                 }
1793                                 if (ref_offset < root_objectid)
1794                                         break;
1795                         }
1796                 }
1797                 ptr += btrfs_extent_inline_ref_size(type);
1798         }
1799         if (err == -ENOENT && insert) {
1800                 if (item_size + extra_size >=
1801                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1802                         err = -EAGAIN;
1803                         goto out;
1804                 }
1805                 /*
1806                  * To add new inline back ref, we have to make sure
1807                  * there is no corresponding back ref item.
1808                  * For simplicity, we just do not add new inline back
1809                  * ref if there is any kind of item for this block
1810                  */
1811                 if (find_next_key(path, 0, &key) == 0 &&
1812                     key.objectid == bytenr &&
1813                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1814                         err = -EAGAIN;
1815                         goto out;
1816                 }
1817         }
1818         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1819 out:
1820         if (insert) {
1821                 path->keep_locks = 0;
1822                 btrfs_unlock_up_safe(path, 1);
1823         }
1824         return err;
1825 }
1826
1827 /*
1828  * helper to add new inline back ref
1829  */
1830 static noinline_for_stack
1831 void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
1832                                  struct btrfs_path *path,
1833                                  struct btrfs_extent_inline_ref *iref,
1834                                  u64 parent, u64 root_objectid,
1835                                  u64 owner, u64 offset, int refs_to_add,
1836                                  struct btrfs_delayed_extent_op *extent_op)
1837 {
1838         struct extent_buffer *leaf;
1839         struct btrfs_extent_item *ei;
1840         unsigned long ptr;
1841         unsigned long end;
1842         unsigned long item_offset;
1843         u64 refs;
1844         int size;
1845         int type;
1846
1847         leaf = path->nodes[0];
1848         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1849         item_offset = (unsigned long)iref - (unsigned long)ei;
1850
1851         type = extent_ref_type(parent, owner);
1852         size = btrfs_extent_inline_ref_size(type);
1853
1854         btrfs_extend_item(fs_info, path, size);
1855
1856         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1857         refs = btrfs_extent_refs(leaf, ei);
1858         refs += refs_to_add;
1859         btrfs_set_extent_refs(leaf, ei, refs);
1860         if (extent_op)
1861                 __run_delayed_extent_op(extent_op, leaf, ei);
1862
1863         ptr = (unsigned long)ei + item_offset;
1864         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1865         if (ptr < end - size)
1866                 memmove_extent_buffer(leaf, ptr + size, ptr,
1867                                       end - size - ptr);
1868
1869         iref = (struct btrfs_extent_inline_ref *)ptr;
1870         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1871         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1872                 struct btrfs_extent_data_ref *dref;
1873                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1874                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1875                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1876                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1877                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1878         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1879                 struct btrfs_shared_data_ref *sref;
1880                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1881                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1882                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1883         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1884                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1885         } else {
1886                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1887         }
1888         btrfs_mark_buffer_dirty(leaf);
1889 }
1890
1891 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1892                                  struct btrfs_fs_info *fs_info,
1893                                  struct btrfs_path *path,
1894                                  struct btrfs_extent_inline_ref **ref_ret,
1895                                  u64 bytenr, u64 num_bytes, u64 parent,
1896                                  u64 root_objectid, u64 owner, u64 offset)
1897 {
1898         int ret;
1899
1900         ret = lookup_inline_extent_backref(trans, fs_info, path, ref_ret,
1901                                            bytenr, num_bytes, parent,
1902                                            root_objectid, owner, offset, 0);
1903         if (ret != -ENOENT)
1904                 return ret;
1905
1906         btrfs_release_path(path);
1907         *ref_ret = NULL;
1908
1909         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1910                 ret = lookup_tree_block_ref(trans, fs_info, path, bytenr,
1911                                             parent, root_objectid);
1912         } else {
1913                 ret = lookup_extent_data_ref(trans, fs_info, path, bytenr,
1914                                              parent, root_objectid, owner,
1915                                              offset);
1916         }
1917         return ret;
1918 }
1919
1920 /*
1921  * helper to update/remove inline back ref
1922  */
1923 static noinline_for_stack
1924 void update_inline_extent_backref(struct btrfs_fs_info *fs_info,
1925                                   struct btrfs_path *path,
1926                                   struct btrfs_extent_inline_ref *iref,
1927                                   int refs_to_mod,
1928                                   struct btrfs_delayed_extent_op *extent_op,
1929                                   int *last_ref)
1930 {
1931         struct extent_buffer *leaf;
1932         struct btrfs_extent_item *ei;
1933         struct btrfs_extent_data_ref *dref = NULL;
1934         struct btrfs_shared_data_ref *sref = NULL;
1935         unsigned long ptr;
1936         unsigned long end;
1937         u32 item_size;
1938         int size;
1939         int type;
1940         u64 refs;
1941
1942         leaf = path->nodes[0];
1943         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1944         refs = btrfs_extent_refs(leaf, ei);
1945         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1946         refs += refs_to_mod;
1947         btrfs_set_extent_refs(leaf, ei, refs);
1948         if (extent_op)
1949                 __run_delayed_extent_op(extent_op, leaf, ei);
1950
1951         /*
1952          * If type is invalid, we should have bailed out after
1953          * lookup_inline_extent_backref().
1954          */
1955         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1956         ASSERT(type != BTRFS_REF_TYPE_INVALID);
1957
1958         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1959                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1960                 refs = btrfs_extent_data_ref_count(leaf, dref);
1961         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1962                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1963                 refs = btrfs_shared_data_ref_count(leaf, sref);
1964         } else {
1965                 refs = 1;
1966                 BUG_ON(refs_to_mod != -1);
1967         }
1968
1969         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1970         refs += refs_to_mod;
1971
1972         if (refs > 0) {
1973                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1974                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1975                 else
1976                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1977         } else {
1978                 *last_ref = 1;
1979                 size =  btrfs_extent_inline_ref_size(type);
1980                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1981                 ptr = (unsigned long)iref;
1982                 end = (unsigned long)ei + item_size;
1983                 if (ptr + size < end)
1984                         memmove_extent_buffer(leaf, ptr, ptr + size,
1985                                               end - ptr - size);
1986                 item_size -= size;
1987                 btrfs_truncate_item(fs_info, path, item_size, 1);
1988         }
1989         btrfs_mark_buffer_dirty(leaf);
1990 }
1991
1992 static noinline_for_stack
1993 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1994                                  struct btrfs_fs_info *fs_info,
1995                                  struct btrfs_path *path,
1996                                  u64 bytenr, u64 num_bytes, u64 parent,
1997                                  u64 root_objectid, u64 owner,
1998                                  u64 offset, int refs_to_add,
1999                                  struct btrfs_delayed_extent_op *extent_op)
2000 {
2001         struct btrfs_extent_inline_ref *iref;
2002         int ret;
2003
2004         ret = lookup_inline_extent_backref(trans, fs_info, path, &iref,
2005                                            bytenr, num_bytes, parent,
2006                                            root_objectid, owner, offset, 1);
2007         if (ret == 0) {
2008                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
2009                 update_inline_extent_backref(fs_info, path, iref,
2010                                              refs_to_add, extent_op, NULL);
2011         } else if (ret == -ENOENT) {
2012                 setup_inline_extent_backref(fs_info, path, iref, parent,
2013                                             root_objectid, owner, offset,
2014                                             refs_to_add, extent_op);
2015                 ret = 0;
2016         }
2017         return ret;
2018 }
2019
2020 static int insert_extent_backref(struct btrfs_trans_handle *trans,
2021                                  struct btrfs_fs_info *fs_info,
2022                                  struct btrfs_path *path,
2023                                  u64 bytenr, u64 parent, u64 root_objectid,
2024                                  u64 owner, u64 offset, int refs_to_add)
2025 {
2026         int ret;
2027         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2028                 BUG_ON(refs_to_add != 1);
2029                 ret = insert_tree_block_ref(trans, fs_info, path, bytenr,
2030                                             parent, root_objectid);
2031         } else {
2032                 ret = insert_extent_data_ref(trans, fs_info, path, bytenr,
2033                                              parent, root_objectid,
2034                                              owner, offset, refs_to_add);
2035         }
2036         return ret;
2037 }
2038
2039 static int remove_extent_backref(struct btrfs_trans_handle *trans,
2040                                  struct btrfs_fs_info *fs_info,
2041                                  struct btrfs_path *path,
2042                                  struct btrfs_extent_inline_ref *iref,
2043                                  int refs_to_drop, int is_data, int *last_ref)
2044 {
2045         int ret = 0;
2046
2047         BUG_ON(!is_data && refs_to_drop != 1);
2048         if (iref) {
2049                 update_inline_extent_backref(fs_info, path, iref,
2050                                              -refs_to_drop, NULL, last_ref);
2051         } else if (is_data) {
2052                 ret = remove_extent_data_ref(trans, fs_info, path, refs_to_drop,
2053                                              last_ref);
2054         } else {
2055                 *last_ref = 1;
2056                 ret = btrfs_del_item(trans, fs_info->extent_root, path);
2057         }
2058         return ret;
2059 }
2060
2061 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
2062 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
2063                                u64 *discarded_bytes)
2064 {
2065         int j, ret = 0;
2066         u64 bytes_left, end;
2067         u64 aligned_start = ALIGN(start, 1 << 9);
2068
2069         if (WARN_ON(start != aligned_start)) {
2070                 len -= aligned_start - start;
2071                 len = round_down(len, 1 << 9);
2072                 start = aligned_start;
2073         }
2074
2075         *discarded_bytes = 0;
2076
2077         if (!len)
2078                 return 0;
2079
2080         end = start + len;
2081         bytes_left = len;
2082
2083         /* Skip any superblocks on this device. */
2084         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
2085                 u64 sb_start = btrfs_sb_offset(j);
2086                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
2087                 u64 size = sb_start - start;
2088
2089                 if (!in_range(sb_start, start, bytes_left) &&
2090                     !in_range(sb_end, start, bytes_left) &&
2091                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
2092                         continue;
2093
2094                 /*
2095                  * Superblock spans beginning of range.  Adjust start and
2096                  * try again.
2097                  */
2098                 if (sb_start <= start) {
2099                         start += sb_end - start;
2100                         if (start > end) {
2101                                 bytes_left = 0;
2102                                 break;
2103                         }
2104                         bytes_left = end - start;
2105                         continue;
2106                 }
2107
2108                 if (size) {
2109                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2110                                                    GFP_NOFS, 0);
2111                         if (!ret)
2112                                 *discarded_bytes += size;
2113                         else if (ret != -EOPNOTSUPP)
2114                                 return ret;
2115                 }
2116
2117                 start = sb_end;
2118                 if (start > end) {
2119                         bytes_left = 0;
2120                         break;
2121                 }
2122                 bytes_left = end - start;
2123         }
2124
2125         if (bytes_left) {
2126                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2127                                            GFP_NOFS, 0);
2128                 if (!ret)
2129                         *discarded_bytes += bytes_left;
2130         }
2131         return ret;
2132 }
2133
2134 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
2135                          u64 num_bytes, u64 *actual_bytes)
2136 {
2137         int ret;
2138         u64 discarded_bytes = 0;
2139         struct btrfs_bio *bbio = NULL;
2140
2141
2142         /*
2143          * Avoid races with device replace and make sure our bbio has devices
2144          * associated to its stripes that don't go away while we are discarding.
2145          */
2146         btrfs_bio_counter_inc_blocked(fs_info);
2147         /* Tell the block device(s) that the sectors can be discarded */
2148         ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
2149                               &bbio, 0);
2150         /* Error condition is -ENOMEM */
2151         if (!ret) {
2152                 struct btrfs_bio_stripe *stripe = bbio->stripes;
2153                 int i;
2154
2155
2156                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2157                         u64 bytes;
2158                         if (!stripe->dev->can_discard)
2159                                 continue;
2160
2161                         ret = btrfs_issue_discard(stripe->dev->bdev,
2162                                                   stripe->physical,
2163                                                   stripe->length,
2164                                                   &bytes);
2165                         if (!ret)
2166                                 discarded_bytes += bytes;
2167                         else if (ret != -EOPNOTSUPP)
2168                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2169
2170                         /*
2171                          * Just in case we get back EOPNOTSUPP for some reason,
2172                          * just ignore the return value so we don't screw up
2173                          * people calling discard_extent.
2174                          */
2175                         ret = 0;
2176                 }
2177                 btrfs_put_bbio(bbio);
2178         }
2179         btrfs_bio_counter_dec(fs_info);
2180
2181         if (actual_bytes)
2182                 *actual_bytes = discarded_bytes;
2183
2184
2185         if (ret == -EOPNOTSUPP)
2186                 ret = 0;
2187         return ret;
2188 }
2189
2190 /* Can return -ENOMEM */
2191 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2192                          struct btrfs_fs_info *fs_info,
2193                          u64 bytenr, u64 num_bytes, u64 parent,
2194                          u64 root_objectid, u64 owner, u64 offset)
2195 {
2196         int old_ref_mod, new_ref_mod;
2197         int ret;
2198
2199         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2200                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2201
2202         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2203                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2204                                                  num_bytes, parent,
2205                                                  root_objectid, (int)owner,
2206                                                  BTRFS_ADD_DELAYED_REF, NULL,
2207                                                  &old_ref_mod, &new_ref_mod);
2208         } else {
2209                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2210                                                  num_bytes, parent,
2211                                                  root_objectid, owner, offset,
2212                                                  0, BTRFS_ADD_DELAYED_REF,
2213                                                  &old_ref_mod, &new_ref_mod);
2214         }
2215
2216         if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0)
2217                 add_pinned_bytes(fs_info, -num_bytes, owner, root_objectid);
2218
2219         return ret;
2220 }
2221
2222 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2223                                   struct btrfs_fs_info *fs_info,
2224                                   struct btrfs_delayed_ref_node *node,
2225                                   u64 parent, u64 root_objectid,
2226                                   u64 owner, u64 offset, int refs_to_add,
2227                                   struct btrfs_delayed_extent_op *extent_op)
2228 {
2229         struct btrfs_path *path;
2230         struct extent_buffer *leaf;
2231         struct btrfs_extent_item *item;
2232         struct btrfs_key key;
2233         u64 bytenr = node->bytenr;
2234         u64 num_bytes = node->num_bytes;
2235         u64 refs;
2236         int ret;
2237
2238         path = btrfs_alloc_path();
2239         if (!path)
2240                 return -ENOMEM;
2241
2242         path->reada = READA_FORWARD;
2243         path->leave_spinning = 1;
2244         /* this will setup the path even if it fails to insert the back ref */
2245         ret = insert_inline_extent_backref(trans, fs_info, path, bytenr,
2246                                            num_bytes, parent, root_objectid,
2247                                            owner, offset,
2248                                            refs_to_add, extent_op);
2249         if ((ret < 0 && ret != -EAGAIN) || !ret)
2250                 goto out;
2251
2252         /*
2253          * Ok we had -EAGAIN which means we didn't have space to insert and
2254          * inline extent ref, so just update the reference count and add a
2255          * normal backref.
2256          */
2257         leaf = path->nodes[0];
2258         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2259         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2260         refs = btrfs_extent_refs(leaf, item);
2261         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2262         if (extent_op)
2263                 __run_delayed_extent_op(extent_op, leaf, item);
2264
2265         btrfs_mark_buffer_dirty(leaf);
2266         btrfs_release_path(path);
2267
2268         path->reada = READA_FORWARD;
2269         path->leave_spinning = 1;
2270         /* now insert the actual backref */
2271         ret = insert_extent_backref(trans, fs_info, path, bytenr, parent,
2272                                     root_objectid, owner, offset, refs_to_add);
2273         if (ret)
2274                 btrfs_abort_transaction(trans, ret);
2275 out:
2276         btrfs_free_path(path);
2277         return ret;
2278 }
2279
2280 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2281                                 struct btrfs_fs_info *fs_info,
2282                                 struct btrfs_delayed_ref_node *node,
2283                                 struct btrfs_delayed_extent_op *extent_op,
2284                                 int insert_reserved)
2285 {
2286         int ret = 0;
2287         struct btrfs_delayed_data_ref *ref;
2288         struct btrfs_key ins;
2289         u64 parent = 0;
2290         u64 ref_root = 0;
2291         u64 flags = 0;
2292
2293         ins.objectid = node->bytenr;
2294         ins.offset = node->num_bytes;
2295         ins.type = BTRFS_EXTENT_ITEM_KEY;
2296
2297         ref = btrfs_delayed_node_to_data_ref(node);
2298         trace_run_delayed_data_ref(fs_info, node, ref, node->action);
2299
2300         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2301                 parent = ref->parent;
2302         ref_root = ref->root;
2303
2304         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2305                 if (extent_op)
2306                         flags |= extent_op->flags_to_set;
2307                 ret = alloc_reserved_file_extent(trans, fs_info,
2308                                                  parent, ref_root, flags,
2309                                                  ref->objectid, ref->offset,
2310                                                  &ins, node->ref_mod);
2311         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2312                 ret = __btrfs_inc_extent_ref(trans, fs_info, node, parent,
2313                                              ref_root, ref->objectid,
2314                                              ref->offset, node->ref_mod,
2315                                              extent_op);
2316         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2317                 ret = __btrfs_free_extent(trans, fs_info, node, parent,
2318                                           ref_root, ref->objectid,
2319                                           ref->offset, node->ref_mod,
2320                                           extent_op);
2321         } else {
2322                 BUG();
2323         }
2324         return ret;
2325 }
2326
2327 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2328                                     struct extent_buffer *leaf,
2329                                     struct btrfs_extent_item *ei)
2330 {
2331         u64 flags = btrfs_extent_flags(leaf, ei);
2332         if (extent_op->update_flags) {
2333                 flags |= extent_op->flags_to_set;
2334                 btrfs_set_extent_flags(leaf, ei, flags);
2335         }
2336
2337         if (extent_op->update_key) {
2338                 struct btrfs_tree_block_info *bi;
2339                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2340                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2341                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2342         }
2343 }
2344
2345 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2346                                  struct btrfs_fs_info *fs_info,
2347                                  struct btrfs_delayed_ref_node *node,
2348                                  struct btrfs_delayed_extent_op *extent_op)
2349 {
2350         struct btrfs_key key;
2351         struct btrfs_path *path;
2352         struct btrfs_extent_item *ei;
2353         struct extent_buffer *leaf;
2354         u32 item_size;
2355         int ret;
2356         int err = 0;
2357         int metadata = !extent_op->is_data;
2358
2359         if (trans->aborted)
2360                 return 0;
2361
2362         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2363                 metadata = 0;
2364
2365         path = btrfs_alloc_path();
2366         if (!path)
2367                 return -ENOMEM;
2368
2369         key.objectid = node->bytenr;
2370
2371         if (metadata) {
2372                 key.type = BTRFS_METADATA_ITEM_KEY;
2373                 key.offset = extent_op->level;
2374         } else {
2375                 key.type = BTRFS_EXTENT_ITEM_KEY;
2376                 key.offset = node->num_bytes;
2377         }
2378
2379 again:
2380         path->reada = READA_FORWARD;
2381         path->leave_spinning = 1;
2382         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
2383         if (ret < 0) {
2384                 err = ret;
2385                 goto out;
2386         }
2387         if (ret > 0) {
2388                 if (metadata) {
2389                         if (path->slots[0] > 0) {
2390                                 path->slots[0]--;
2391                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2392                                                       path->slots[0]);
2393                                 if (key.objectid == node->bytenr &&
2394                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2395                                     key.offset == node->num_bytes)
2396                                         ret = 0;
2397                         }
2398                         if (ret > 0) {
2399                                 btrfs_release_path(path);
2400                                 metadata = 0;
2401
2402                                 key.objectid = node->bytenr;
2403                                 key.offset = node->num_bytes;
2404                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2405                                 goto again;
2406                         }
2407                 } else {
2408                         err = -EIO;
2409                         goto out;
2410                 }
2411         }
2412
2413         leaf = path->nodes[0];
2414         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2415 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2416         if (item_size < sizeof(*ei)) {
2417                 ret = convert_extent_item_v0(trans, fs_info, path, (u64)-1, 0);
2418                 if (ret < 0) {
2419                         err = ret;
2420                         goto out;
2421                 }
2422                 leaf = path->nodes[0];
2423                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2424         }
2425 #endif
2426         BUG_ON(item_size < sizeof(*ei));
2427         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2428         __run_delayed_extent_op(extent_op, leaf, ei);
2429
2430         btrfs_mark_buffer_dirty(leaf);
2431 out:
2432         btrfs_free_path(path);
2433         return err;
2434 }
2435
2436 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2437                                 struct btrfs_fs_info *fs_info,
2438                                 struct btrfs_delayed_ref_node *node,
2439                                 struct btrfs_delayed_extent_op *extent_op,
2440                                 int insert_reserved)
2441 {
2442         int ret = 0;
2443         struct btrfs_delayed_tree_ref *ref;
2444         struct btrfs_key ins;
2445         u64 parent = 0;
2446         u64 ref_root = 0;
2447         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
2448
2449         ref = btrfs_delayed_node_to_tree_ref(node);
2450         trace_run_delayed_tree_ref(fs_info, node, ref, node->action);
2451
2452         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2453                 parent = ref->parent;
2454         ref_root = ref->root;
2455
2456         ins.objectid = node->bytenr;
2457         if (skinny_metadata) {
2458                 ins.offset = ref->level;
2459                 ins.type = BTRFS_METADATA_ITEM_KEY;
2460         } else {
2461                 ins.offset = node->num_bytes;
2462                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2463         }
2464
2465         if (node->ref_mod != 1) {
2466                 btrfs_err(fs_info,
2467         "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
2468                           node->bytenr, node->ref_mod, node->action, ref_root,
2469                           parent);
2470                 return -EIO;
2471         }
2472         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2473                 BUG_ON(!extent_op || !extent_op->update_flags);
2474                 ret = alloc_reserved_tree_block(trans, fs_info,
2475                                                 parent, ref_root,
2476                                                 extent_op->flags_to_set,
2477                                                 &extent_op->key,
2478                                                 ref->level, &ins);
2479         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2480                 ret = __btrfs_inc_extent_ref(trans, fs_info, node,
2481                                              parent, ref_root,
2482                                              ref->level, 0, 1,
2483                                              extent_op);
2484         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2485                 ret = __btrfs_free_extent(trans, fs_info, node,
2486                                           parent, ref_root,
2487                                           ref->level, 0, 1, extent_op);
2488         } else {
2489                 BUG();
2490         }
2491         return ret;
2492 }
2493
2494 /* helper function to actually process a single delayed ref entry */
2495 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2496                                struct btrfs_fs_info *fs_info,
2497                                struct btrfs_delayed_ref_node *node,
2498                                struct btrfs_delayed_extent_op *extent_op,
2499                                int insert_reserved)
2500 {
2501         int ret = 0;
2502
2503         if (trans->aborted) {
2504                 if (insert_reserved)
2505                         btrfs_pin_extent(fs_info, node->bytenr,
2506                                          node->num_bytes, 1);
2507                 return 0;
2508         }
2509
2510         if (btrfs_delayed_ref_is_head(node)) {
2511                 struct btrfs_delayed_ref_head *head;
2512                 /*
2513                  * we've hit the end of the chain and we were supposed
2514                  * to insert this extent into the tree.  But, it got
2515                  * deleted before we ever needed to insert it, so all
2516                  * we have to do is clean up the accounting
2517                  */
2518                 BUG_ON(extent_op);
2519                 head = btrfs_delayed_node_to_head(node);
2520                 trace_run_delayed_ref_head(fs_info, node, head, node->action);
2521
2522                 if (head->total_ref_mod < 0) {
2523                         struct btrfs_block_group_cache *cache;
2524
2525                         cache = btrfs_lookup_block_group(fs_info, node->bytenr);
2526                         ASSERT(cache);
2527                         percpu_counter_add(&cache->space_info->total_bytes_pinned,
2528                                            -node->num_bytes);
2529                         btrfs_put_block_group(cache);
2530                 }
2531
2532                 if (insert_reserved) {
2533                         btrfs_pin_extent(fs_info, node->bytenr,
2534                                          node->num_bytes, 1);
2535                         if (head->is_data) {
2536                                 ret = btrfs_del_csums(trans, fs_info,
2537                                                       node->bytenr,
2538                                                       node->num_bytes);
2539                         }
2540                 }
2541
2542                 /* Also free its reserved qgroup space */
2543                 btrfs_qgroup_free_delayed_ref(fs_info, head->qgroup_ref_root,
2544                                               head->qgroup_reserved);
2545                 return ret;
2546         }
2547
2548         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2549             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2550                 ret = run_delayed_tree_ref(trans, fs_info, node, extent_op,
2551                                            insert_reserved);
2552         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2553                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2554                 ret = run_delayed_data_ref(trans, fs_info, node, extent_op,
2555                                            insert_reserved);
2556         else
2557                 BUG();
2558         return ret;
2559 }
2560
2561 static inline struct btrfs_delayed_ref_node *
2562 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2563 {
2564         struct btrfs_delayed_ref_node *ref;
2565
2566         if (list_empty(&head->ref_list))
2567                 return NULL;
2568
2569         /*
2570          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2571          * This is to prevent a ref count from going down to zero, which deletes
2572          * the extent item from the extent tree, when there still are references
2573          * to add, which would fail because they would not find the extent item.
2574          */
2575         if (!list_empty(&head->ref_add_list))
2576                 return list_first_entry(&head->ref_add_list,
2577                                 struct btrfs_delayed_ref_node, add_list);
2578
2579         ref = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
2580                                list);
2581         ASSERT(list_empty(&ref->add_list));
2582         return ref;
2583 }
2584
2585 /*
2586  * Returns 0 on success or if called with an already aborted transaction.
2587  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2588  */
2589 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2590                                              struct btrfs_fs_info *fs_info,
2591                                              unsigned long nr)
2592 {
2593         struct btrfs_delayed_ref_root *delayed_refs;
2594         struct btrfs_delayed_ref_node *ref;
2595         struct btrfs_delayed_ref_head *locked_ref = NULL;
2596         struct btrfs_delayed_extent_op *extent_op;
2597         ktime_t start = ktime_get();
2598         int ret;
2599         unsigned long count = 0;
2600         unsigned long actual_count = 0;
2601         int must_insert_reserved = 0;
2602
2603         delayed_refs = &trans->transaction->delayed_refs;
2604         while (1) {
2605                 if (!locked_ref) {
2606                         if (count >= nr)
2607                                 break;
2608
2609                         spin_lock(&delayed_refs->lock);
2610                         locked_ref = btrfs_select_ref_head(trans);
2611                         if (!locked_ref) {
2612                                 spin_unlock(&delayed_refs->lock);
2613                                 break;
2614                         }
2615
2616                         /* grab the lock that says we are going to process
2617                          * all the refs for this head */
2618                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2619                         spin_unlock(&delayed_refs->lock);
2620                         /*
2621                          * we may have dropped the spin lock to get the head
2622                          * mutex lock, and that might have given someone else
2623                          * time to free the head.  If that's true, it has been
2624                          * removed from our list and we can move on.
2625                          */
2626                         if (ret == -EAGAIN) {
2627                                 locked_ref = NULL;
2628                                 count++;
2629                                 continue;
2630                         }
2631                 }
2632
2633                 /*
2634                  * We need to try and merge add/drops of the same ref since we
2635                  * can run into issues with relocate dropping the implicit ref
2636                  * and then it being added back again before the drop can
2637                  * finish.  If we merged anything we need to re-loop so we can
2638                  * get a good ref.
2639                  * Or we can get node references of the same type that weren't
2640                  * merged when created due to bumps in the tree mod seq, and
2641                  * we need to merge them to prevent adding an inline extent
2642                  * backref before dropping it (triggering a BUG_ON at
2643                  * insert_inline_extent_backref()).
2644                  */
2645                 spin_lock(&locked_ref->lock);
2646                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2647                                          locked_ref);
2648
2649                 /*
2650                  * locked_ref is the head node, so we have to go one
2651                  * node back for any delayed ref updates
2652                  */
2653                 ref = select_delayed_ref(locked_ref);
2654
2655                 if (ref && ref->seq &&
2656                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2657                         spin_unlock(&locked_ref->lock);
2658                         spin_lock(&delayed_refs->lock);
2659                         locked_ref->processing = 0;
2660                         delayed_refs->num_heads_ready++;
2661                         spin_unlock(&delayed_refs->lock);
2662                         btrfs_delayed_ref_unlock(locked_ref);
2663                         locked_ref = NULL;
2664                         cond_resched();
2665                         count++;
2666                         continue;
2667                 }
2668
2669                 /*
2670                  * record the must insert reserved flag before we
2671                  * drop the spin lock.
2672                  */
2673                 must_insert_reserved = locked_ref->must_insert_reserved;
2674                 locked_ref->must_insert_reserved = 0;
2675
2676                 extent_op = locked_ref->extent_op;
2677                 locked_ref->extent_op = NULL;
2678
2679                 if (!ref) {
2680
2681
2682                         /* All delayed refs have been processed, Go ahead
2683                          * and send the head node to run_one_delayed_ref,
2684                          * so that any accounting fixes can happen
2685                          */
2686                         ref = &locked_ref->node;
2687
2688                         if (extent_op && must_insert_reserved) {
2689                                 btrfs_free_delayed_extent_op(extent_op);
2690                                 extent_op = NULL;
2691                         }
2692
2693                         if (extent_op) {
2694                                 spin_unlock(&locked_ref->lock);
2695                                 ret = run_delayed_extent_op(trans, fs_info,
2696                                                             ref, extent_op);
2697                                 btrfs_free_delayed_extent_op(extent_op);
2698
2699                                 if (ret) {
2700                                         /*
2701                                          * Need to reset must_insert_reserved if
2702                                          * there was an error so the abort stuff
2703                                          * can cleanup the reserved space
2704                                          * properly.
2705                                          */
2706                                         if (must_insert_reserved)
2707                                                 locked_ref->must_insert_reserved = 1;
2708                                         spin_lock(&delayed_refs->lock);
2709                                         locked_ref->processing = 0;
2710                                         delayed_refs->num_heads_ready++;
2711                                         spin_unlock(&delayed_refs->lock);
2712                                         btrfs_debug(fs_info,
2713                                                     "run_delayed_extent_op returned %d",
2714                                                     ret);
2715                                         btrfs_delayed_ref_unlock(locked_ref);
2716                                         return ret;
2717                                 }
2718                                 continue;
2719                         }
2720
2721                         /*
2722                          * Need to drop our head ref lock and re-acquire the
2723                          * delayed ref lock and then re-check to make sure
2724                          * nobody got added.
2725                          */
2726                         spin_unlock(&locked_ref->lock);
2727                         spin_lock(&delayed_refs->lock);
2728                         spin_lock(&locked_ref->lock);
2729                         if (!list_empty(&locked_ref->ref_list) ||
2730                             locked_ref->extent_op) {
2731                                 spin_unlock(&locked_ref->lock);
2732                                 spin_unlock(&delayed_refs->lock);
2733                                 continue;
2734                         }
2735                         ref->in_tree = 0;
2736                         delayed_refs->num_heads--;
2737                         rb_erase(&locked_ref->href_node,
2738                                  &delayed_refs->href_root);
2739                         spin_unlock(&delayed_refs->lock);
2740                 } else {
2741                         actual_count++;
2742                         ref->in_tree = 0;
2743                         list_del(&ref->list);
2744                         if (!list_empty(&ref->add_list))
2745                                 list_del(&ref->add_list);
2746                 }
2747                 atomic_dec(&delayed_refs->num_entries);
2748
2749                 if (!btrfs_delayed_ref_is_head(ref)) {
2750                         /*
2751                          * when we play the delayed ref, also correct the
2752                          * ref_mod on head
2753                          */
2754                         switch (ref->action) {
2755                         case BTRFS_ADD_DELAYED_REF:
2756                         case BTRFS_ADD_DELAYED_EXTENT:
2757                                 locked_ref->node.ref_mod -= ref->ref_mod;
2758                                 break;
2759                         case BTRFS_DROP_DELAYED_REF:
2760                                 locked_ref->node.ref_mod += ref->ref_mod;
2761                                 break;
2762                         default:
2763                                 WARN_ON(1);
2764                         }
2765                 }
2766                 spin_unlock(&locked_ref->lock);
2767
2768                 ret = run_one_delayed_ref(trans, fs_info, ref, extent_op,
2769                                           must_insert_reserved);
2770
2771                 btrfs_free_delayed_extent_op(extent_op);
2772                 if (ret) {
2773                         spin_lock(&delayed_refs->lock);
2774                         locked_ref->processing = 0;
2775                         delayed_refs->num_heads_ready++;
2776                         spin_unlock(&delayed_refs->lock);
2777                         btrfs_delayed_ref_unlock(locked_ref);
2778                         btrfs_put_delayed_ref(ref);
2779                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
2780                                     ret);
2781                         return ret;
2782                 }
2783
2784                 /*
2785                  * If this node is a head, that means all the refs in this head
2786                  * have been dealt with, and we will pick the next head to deal
2787                  * with, so we must unlock the head and drop it from the cluster
2788                  * list before we release it.
2789                  */
2790                 if (btrfs_delayed_ref_is_head(ref)) {
2791                         if (locked_ref->is_data &&
2792                             locked_ref->total_ref_mod < 0) {
2793                                 spin_lock(&delayed_refs->lock);
2794                                 delayed_refs->pending_csums -= ref->num_bytes;
2795                                 spin_unlock(&delayed_refs->lock);
2796                         }
2797                         btrfs_delayed_ref_unlock(locked_ref);
2798                         locked_ref = NULL;
2799                 }
2800                 btrfs_put_delayed_ref(ref);
2801                 count++;
2802                 cond_resched();
2803         }
2804
2805         /*
2806          * We don't want to include ref heads since we can have empty ref heads
2807          * and those will drastically skew our runtime down since we just do
2808          * accounting, no actual extent tree updates.
2809          */
2810         if (actual_count > 0) {
2811                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2812                 u64 avg;
2813
2814                 /*
2815                  * We weigh the current average higher than our current runtime
2816                  * to avoid large swings in the average.
2817                  */
2818                 spin_lock(&delayed_refs->lock);
2819                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2820                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2821                 spin_unlock(&delayed_refs->lock);
2822         }
2823         return 0;
2824 }
2825
2826 #ifdef SCRAMBLE_DELAYED_REFS
2827 /*
2828  * Normally delayed refs get processed in ascending bytenr order. This
2829  * correlates in most cases to the order added. To expose dependencies on this
2830  * order, we start to process the tree in the middle instead of the beginning
2831  */
2832 static u64 find_middle(struct rb_root *root)
2833 {
2834         struct rb_node *n = root->rb_node;
2835         struct btrfs_delayed_ref_node *entry;
2836         int alt = 1;
2837         u64 middle;
2838         u64 first = 0, last = 0;
2839
2840         n = rb_first(root);
2841         if (n) {
2842                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2843                 first = entry->bytenr;
2844         }
2845         n = rb_last(root);
2846         if (n) {
2847                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2848                 last = entry->bytenr;
2849         }
2850         n = root->rb_node;
2851
2852         while (n) {
2853                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2854                 WARN_ON(!entry->in_tree);
2855
2856                 middle = entry->bytenr;
2857
2858                 if (alt)
2859                         n = n->rb_left;
2860                 else
2861                         n = n->rb_right;
2862
2863                 alt = 1 - alt;
2864         }
2865         return middle;
2866 }
2867 #endif
2868
2869 static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
2870 {
2871         u64 num_bytes;
2872
2873         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2874                              sizeof(struct btrfs_extent_inline_ref));
2875         if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2876                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2877
2878         /*
2879          * We don't ever fill up leaves all the way so multiply by 2 just to be
2880          * closer to what we're really going to want to use.
2881          */
2882         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
2883 }
2884
2885 /*
2886  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2887  * would require to store the csums for that many bytes.
2888  */
2889 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2890 {
2891         u64 csum_size;
2892         u64 num_csums_per_leaf;
2893         u64 num_csums;
2894
2895         csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2896         num_csums_per_leaf = div64_u64(csum_size,
2897                         (u64)btrfs_super_csum_size(fs_info->super_copy));
2898         num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2899         num_csums += num_csums_per_leaf - 1;
2900         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2901         return num_csums;
2902 }
2903
2904 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2905                                        struct btrfs_fs_info *fs_info)
2906 {
2907         struct btrfs_block_rsv *global_rsv;
2908         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2909         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2910         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2911         u64 num_bytes, num_dirty_bgs_bytes;
2912         int ret = 0;
2913
2914         num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
2915         num_heads = heads_to_leaves(fs_info, num_heads);
2916         if (num_heads > 1)
2917                 num_bytes += (num_heads - 1) * fs_info->nodesize;
2918         num_bytes <<= 1;
2919         num_bytes += btrfs_csum_bytes_to_leaves(fs_info, csum_bytes) *
2920                                                         fs_info->nodesize;
2921         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(fs_info,
2922                                                              num_dirty_bgs);
2923         global_rsv = &fs_info->global_block_rsv;
2924
2925         /*
2926          * If we can't allocate any more chunks lets make sure we have _lots_ of
2927          * wiggle room since running delayed refs can create more delayed refs.
2928          */
2929         if (global_rsv->space_info->full) {
2930                 num_dirty_bgs_bytes <<= 1;
2931                 num_bytes <<= 1;
2932         }
2933
2934         spin_lock(&global_rsv->lock);
2935         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2936                 ret = 1;
2937         spin_unlock(&global_rsv->lock);
2938         return ret;
2939 }
2940
2941 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2942                                        struct btrfs_fs_info *fs_info)
2943 {
2944         u64 num_entries =
2945                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2946         u64 avg_runtime;
2947         u64 val;
2948
2949         smp_mb();
2950         avg_runtime = fs_info->avg_delayed_ref_runtime;
2951         val = num_entries * avg_runtime;
2952         if (val >= NSEC_PER_SEC)
2953                 return 1;
2954         if (val >= NSEC_PER_SEC / 2)
2955                 return 2;
2956
2957         return btrfs_check_space_for_delayed_refs(trans, fs_info);
2958 }
2959
2960 struct async_delayed_refs {
2961         struct btrfs_root *root;
2962         u64 transid;
2963         int count;
2964         int error;
2965         int sync;
2966         struct completion wait;
2967         struct btrfs_work work;
2968 };
2969
2970 static inline struct async_delayed_refs *
2971 to_async_delayed_refs(struct btrfs_work *work)
2972 {
2973         return container_of(work, struct async_delayed_refs, work);
2974 }
2975
2976 static void delayed_ref_async_start(struct btrfs_work *work)
2977 {
2978         struct async_delayed_refs *async = to_async_delayed_refs(work);
2979         struct btrfs_trans_handle *trans;
2980         struct btrfs_fs_info *fs_info = async->root->fs_info;
2981         int ret;
2982
2983         /* if the commit is already started, we don't need to wait here */
2984         if (btrfs_transaction_blocked(fs_info))
2985                 goto done;
2986
2987         trans = btrfs_join_transaction(async->root);
2988         if (IS_ERR(trans)) {
2989                 async->error = PTR_ERR(trans);
2990                 goto done;
2991         }
2992
2993         /*
2994          * trans->sync means that when we call end_transaction, we won't
2995          * wait on delayed refs
2996          */
2997         trans->sync = true;
2998
2999         /* Don't bother flushing if we got into a different transaction */
3000         if (trans->transid > async->transid)
3001                 goto end;
3002
3003         ret = btrfs_run_delayed_refs(trans, fs_info, async->count);
3004         if (ret)
3005                 async->error = ret;
3006 end:
3007         ret = btrfs_end_transaction(trans);
3008         if (ret && !async->error)
3009                 async->error = ret;
3010 done:
3011         if (async->sync)
3012                 complete(&async->wait);
3013         else
3014                 kfree(async);
3015 }
3016
3017 int btrfs_async_run_delayed_refs(struct btrfs_fs_info *fs_info,
3018                                  unsigned long count, u64 transid, int wait)
3019 {
3020         struct async_delayed_refs *async;
3021         int ret;
3022
3023         async = kmalloc(sizeof(*async), GFP_NOFS);
3024         if (!async)
3025                 return -ENOMEM;
3026
3027         async->root = fs_info->tree_root;
3028         async->count = count;
3029         async->error = 0;
3030         async->transid = transid;
3031         if (wait)
3032                 async->sync = 1;
3033         else
3034                 async->sync = 0;
3035         init_completion(&async->wait);
3036
3037         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
3038                         delayed_ref_async_start, NULL, NULL);
3039
3040         btrfs_queue_work(fs_info->extent_workers, &async->work);
3041
3042         if (wait) {
3043                 wait_for_completion(&async->wait);
3044                 ret = async->error;
3045                 kfree(async);
3046                 return ret;
3047         }
3048         return 0;
3049 }
3050
3051 /*
3052  * this starts processing the delayed reference count updates and
3053  * extent insertions we have queued up so far.  count can be
3054  * 0, which means to process everything in the tree at the start
3055  * of the run (but not newly added entries), or it can be some target
3056  * number you'd like to process.
3057  *
3058  * Returns 0 on success or if called with an aborted transaction
3059  * Returns <0 on error and aborts the transaction
3060  */
3061 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
3062                            struct btrfs_fs_info *fs_info, unsigned long count)
3063 {
3064         struct rb_node *node;
3065         struct btrfs_delayed_ref_root *delayed_refs;
3066         struct btrfs_delayed_ref_head *head;
3067         int ret;
3068         int run_all = count == (unsigned long)-1;
3069         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
3070
3071         /* We'll clean this up in btrfs_cleanup_transaction */
3072         if (trans->aborted)
3073                 return 0;
3074
3075         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
3076                 return 0;
3077
3078         delayed_refs = &trans->transaction->delayed_refs;
3079         if (count == 0)
3080                 count = atomic_read(&delayed_refs->num_entries) * 2;
3081
3082 again:
3083 #ifdef SCRAMBLE_DELAYED_REFS
3084         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
3085 #endif
3086         trans->can_flush_pending_bgs = false;
3087         ret = __btrfs_run_delayed_refs(trans, fs_info, count);
3088         if (ret < 0) {
3089                 btrfs_abort_transaction(trans, ret);
3090                 return ret;
3091         }
3092
3093         if (run_all) {
3094                 if (!list_empty(&trans->new_bgs))
3095                         btrfs_create_pending_block_groups(trans, fs_info);
3096
3097                 spin_lock(&delayed_refs->lock);
3098                 node = rb_first(&delayed_refs->href_root);
3099                 if (!node) {
3100                         spin_unlock(&delayed_refs->lock);
3101                         goto out;
3102                 }
3103
3104                 while (node) {
3105                         head = rb_entry(node, struct btrfs_delayed_ref_head,
3106                                         href_node);
3107                         if (btrfs_delayed_ref_is_head(&head->node)) {
3108                                 struct btrfs_delayed_ref_node *ref;
3109
3110                                 ref = &head->node;
3111                                 refcount_inc(&ref->refs);
3112
3113                                 spin_unlock(&delayed_refs->lock);
3114                                 /*
3115                                  * Mutex was contended, block until it's
3116                                  * released and try again
3117                                  */
3118                                 mutex_lock(&head->mutex);
3119                                 mutex_unlock(&head->mutex);
3120
3121                                 btrfs_put_delayed_ref(ref);
3122                                 cond_resched();
3123                                 goto again;
3124                         } else {
3125                                 WARN_ON(1);
3126                         }
3127                         node = rb_next(node);
3128                 }
3129                 spin_unlock(&delayed_refs->lock);
3130                 cond_resched();
3131                 goto again;
3132         }
3133 out:
3134         trans->can_flush_pending_bgs = can_flush_pending_bgs;
3135         return 0;
3136 }
3137
3138 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3139                                 struct btrfs_fs_info *fs_info,
3140                                 u64 bytenr, u64 num_bytes, u64 flags,
3141                                 int level, int is_data)
3142 {
3143         struct btrfs_delayed_extent_op *extent_op;
3144         int ret;
3145
3146         extent_op = btrfs_alloc_delayed_extent_op();
3147         if (!extent_op)
3148                 return -ENOMEM;
3149
3150         extent_op->flags_to_set = flags;
3151         extent_op->update_flags = true;
3152         extent_op->update_key = false;
3153         extent_op->is_data = is_data ? true : false;
3154         extent_op->level = level;
3155
3156         ret = btrfs_add_delayed_extent_op(fs_info, trans, bytenr,
3157                                           num_bytes, extent_op);
3158         if (ret)
3159                 btrfs_free_delayed_extent_op(extent_op);
3160         return ret;
3161 }
3162
3163 static noinline int check_delayed_ref(struct btrfs_root *root,
3164                                       struct btrfs_path *path,
3165                                       u64 objectid, u64 offset, u64 bytenr)
3166 {
3167         struct btrfs_delayed_ref_head *head;
3168         struct btrfs_delayed_ref_node *ref;
3169         struct btrfs_delayed_data_ref *data_ref;
3170         struct btrfs_delayed_ref_root *delayed_refs;
3171         struct btrfs_transaction *cur_trans;
3172         int ret = 0;
3173
3174         cur_trans = root->fs_info->running_transaction;
3175         if (!cur_trans)
3176                 return 0;
3177
3178         delayed_refs = &cur_trans->delayed_refs;
3179         spin_lock(&delayed_refs->lock);
3180         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3181         if (!head) {
3182                 spin_unlock(&delayed_refs->lock);
3183                 return 0;
3184         }
3185
3186         if (!mutex_trylock(&head->mutex)) {
3187                 refcount_inc(&head->node.refs);
3188                 spin_unlock(&delayed_refs->lock);
3189
3190                 btrfs_release_path(path);
3191
3192                 /*
3193                  * Mutex was contended, block until it's released and let
3194                  * caller try again
3195                  */
3196                 mutex_lock(&head->mutex);
3197                 mutex_unlock(&head->mutex);
3198                 btrfs_put_delayed_ref(&head->node);
3199                 return -EAGAIN;
3200         }
3201         spin_unlock(&delayed_refs->lock);
3202
3203         spin_lock(&head->lock);
3204         list_for_each_entry(ref, &head->ref_list, list) {
3205                 /* If it's a shared ref we know a cross reference exists */
3206                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3207                         ret = 1;
3208                         break;
3209                 }
3210
3211                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3212
3213                 /*
3214                  * If our ref doesn't match the one we're currently looking at
3215                  * then we have a cross reference.
3216                  */
3217                 if (data_ref->root != root->root_key.objectid ||
3218                     data_ref->objectid != objectid ||
3219                     data_ref->offset != offset) {
3220                         ret = 1;
3221                         break;
3222                 }
3223         }
3224         spin_unlock(&head->lock);
3225         mutex_unlock(&head->mutex);
3226         return ret;
3227 }
3228
3229 static noinline int check_committed_ref(struct btrfs_root *root,
3230                                         struct btrfs_path *path,
3231                                         u64 objectid, u64 offset, u64 bytenr)
3232 {
3233         struct btrfs_fs_info *fs_info = root->fs_info;
3234         struct btrfs_root *extent_root = fs_info->extent_root;
3235         struct extent_buffer *leaf;
3236         struct btrfs_extent_data_ref *ref;
3237         struct btrfs_extent_inline_ref *iref;
3238         struct btrfs_extent_item *ei;
3239         struct btrfs_key key;
3240         u32 item_size;
3241         int type;
3242         int ret;
3243
3244         key.objectid = bytenr;
3245         key.offset = (u64)-1;
3246         key.type = BTRFS_EXTENT_ITEM_KEY;
3247
3248         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3249         if (ret < 0)
3250                 goto out;
3251         BUG_ON(ret == 0); /* Corruption */
3252
3253         ret = -ENOENT;
3254         if (path->slots[0] == 0)
3255                 goto out;
3256
3257         path->slots[0]--;
3258         leaf = path->nodes[0];
3259         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3260
3261         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3262                 goto out;
3263
3264         ret = 1;
3265         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3266 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3267         if (item_size < sizeof(*ei)) {
3268                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3269                 goto out;
3270         }
3271 #endif
3272         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3273
3274         if (item_size != sizeof(*ei) +
3275             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3276                 goto out;
3277
3278         if (btrfs_extent_generation(leaf, ei) <=
3279             btrfs_root_last_snapshot(&root->root_item))
3280                 goto out;
3281
3282         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3283
3284         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
3285         if (type != BTRFS_EXTENT_DATA_REF_KEY)
3286                 goto out;
3287
3288         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3289         if (btrfs_extent_refs(leaf, ei) !=
3290             btrfs_extent_data_ref_count(leaf, ref) ||
3291             btrfs_extent_data_ref_root(leaf, ref) !=
3292             root->root_key.objectid ||
3293             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3294             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3295                 goto out;
3296
3297         ret = 0;
3298 out:
3299         return ret;
3300 }
3301
3302 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
3303                           u64 bytenr)
3304 {
3305         struct btrfs_path *path;
3306         int ret;
3307         int ret2;
3308
3309         path = btrfs_alloc_path();
3310         if (!path)
3311                 return -ENOENT;
3312
3313         do {
3314                 ret = check_committed_ref(root, path, objectid,
3315                                           offset, bytenr);
3316                 if (ret && ret != -ENOENT)
3317                         goto out;
3318
3319                 ret2 = check_delayed_ref(root, path, objectid,
3320                                          offset, bytenr);
3321         } while (ret2 == -EAGAIN);
3322
3323         if (ret2 && ret2 != -ENOENT) {
3324                 ret = ret2;
3325                 goto out;
3326         }
3327
3328         if (ret != -ENOENT || ret2 != -ENOENT)
3329                 ret = 0;
3330 out:
3331         btrfs_free_path(path);
3332         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3333                 WARN_ON(ret > 0);
3334         return ret;
3335 }
3336
3337 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3338                            struct btrfs_root *root,
3339                            struct extent_buffer *buf,
3340                            int full_backref, int inc)
3341 {
3342         struct btrfs_fs_info *fs_info = root->fs_info;
3343         u64 bytenr;
3344         u64 num_bytes;
3345         u64 parent;
3346         u64 ref_root;
3347         u32 nritems;
3348         struct btrfs_key key;
3349         struct btrfs_file_extent_item *fi;
3350         int i;
3351         int level;
3352         int ret = 0;
3353         int (*process_func)(struct btrfs_trans_handle *,
3354                             struct btrfs_fs_info *,
3355                             u64, u64, u64, u64, u64, u64);
3356
3357
3358         if (btrfs_is_testing(fs_info))
3359                 return 0;
3360
3361         ref_root = btrfs_header_owner(buf);
3362         nritems = btrfs_header_nritems(buf);
3363         level = btrfs_header_level(buf);
3364
3365         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3366                 return 0;
3367
3368         if (inc)
3369                 process_func = btrfs_inc_extent_ref;
3370         else
3371                 process_func = btrfs_free_extent;
3372
3373         if (full_backref)
3374                 parent = buf->start;
3375         else
3376                 parent = 0;
3377
3378         for (i = 0; i < nritems; i++) {
3379                 if (level == 0) {
3380                         btrfs_item_key_to_cpu(buf, &key, i);
3381                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3382                                 continue;
3383                         fi = btrfs_item_ptr(buf, i,
3384                                             struct btrfs_file_extent_item);
3385                         if (btrfs_file_extent_type(buf, fi) ==
3386                             BTRFS_FILE_EXTENT_INLINE)
3387                                 continue;
3388                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3389                         if (bytenr == 0)
3390                                 continue;
3391
3392                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3393                         key.offset -= btrfs_file_extent_offset(buf, fi);
3394                         ret = process_func(trans, fs_info, bytenr, num_bytes,
3395                                            parent, ref_root, key.objectid,
3396                                            key.offset);
3397                         if (ret)
3398                                 goto fail;
3399                 } else {
3400                         bytenr = btrfs_node_blockptr(buf, i);
3401                         num_bytes = fs_info->nodesize;
3402                         ret = process_func(trans, fs_info, bytenr, num_bytes,
3403                                            parent, ref_root, level - 1, 0);
3404                         if (ret)
3405                                 goto fail;
3406                 }
3407         }
3408         return 0;
3409 fail:
3410         return ret;
3411 }
3412
3413 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3414                   struct extent_buffer *buf, int full_backref)
3415 {
3416         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3417 }
3418
3419 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3420                   struct extent_buffer *buf, int full_backref)
3421 {
3422         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3423 }
3424
3425 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3426                                  struct btrfs_fs_info *fs_info,
3427                                  struct btrfs_path *path,
3428                                  struct btrfs_block_group_cache *cache)
3429 {
3430         int ret;
3431         struct btrfs_root *extent_root = fs_info->extent_root;
3432         unsigned long bi;
3433         struct extent_buffer *leaf;
3434
3435         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3436         if (ret) {
3437                 if (ret > 0)
3438                         ret = -ENOENT;
3439                 goto fail;
3440         }
3441
3442         leaf = path->nodes[0];
3443         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3444         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3445         btrfs_mark_buffer_dirty(leaf);
3446 fail:
3447         btrfs_release_path(path);
3448         return ret;
3449
3450 }
3451
3452 static struct btrfs_block_group_cache *
3453 next_block_group(struct btrfs_fs_info *fs_info,
3454                  struct btrfs_block_group_cache *cache)
3455 {
3456         struct rb_node *node;
3457
3458         spin_lock(&fs_info->block_group_cache_lock);
3459
3460         /* If our block group was removed, we need a full search. */
3461         if (RB_EMPTY_NODE(&cache->cache_node)) {
3462                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3463
3464                 spin_unlock(&fs_info->block_group_cache_lock);
3465                 btrfs_put_block_group(cache);
3466                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
3467         }
3468         node = rb_next(&cache->cache_node);
3469         btrfs_put_block_group(cache);
3470         if (node) {
3471                 cache = rb_entry(node, struct btrfs_block_group_cache,
3472                                  cache_node);
3473                 btrfs_get_block_group(cache);
3474         } else
3475                 cache = NULL;
3476         spin_unlock(&fs_info->block_group_cache_lock);
3477         return cache;
3478 }
3479
3480 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3481                             struct btrfs_trans_handle *trans,
3482                             struct btrfs_path *path)
3483 {
3484         struct btrfs_fs_info *fs_info = block_group->fs_info;
3485         struct btrfs_root *root = fs_info->tree_root;
3486         struct inode *inode = NULL;
3487         struct extent_changeset *data_reserved = NULL;
3488         u64 alloc_hint = 0;
3489         int dcs = BTRFS_DC_ERROR;
3490         u64 num_pages = 0;
3491         int retries = 0;
3492         int ret = 0;
3493
3494         /*
3495          * If this block group is smaller than 100 megs don't bother caching the
3496          * block group.
3497          */
3498         if (block_group->key.offset < (100 * SZ_1M)) {
3499                 spin_lock(&block_group->lock);
3500                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3501                 spin_unlock(&block_group->lock);
3502                 return 0;
3503         }
3504
3505         if (trans->aborted)
3506                 return 0;
3507 again:
3508         inode = lookup_free_space_inode(fs_info, block_group, path);
3509         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3510                 ret = PTR_ERR(inode);
3511                 btrfs_release_path(path);
3512                 goto out;
3513         }
3514
3515         if (IS_ERR(inode)) {
3516                 BUG_ON(retries);
3517                 retries++;
3518
3519                 if (block_group->ro)
3520                         goto out_free;
3521
3522                 ret = create_free_space_inode(fs_info, trans, block_group,
3523                                               path);
3524                 if (ret)
3525                         goto out_free;
3526                 goto again;
3527         }
3528
3529         /* We've already setup this transaction, go ahead and exit */
3530         if (block_group->cache_generation == trans->transid &&
3531             i_size_read(inode)) {
3532                 dcs = BTRFS_DC_SETUP;
3533                 goto out_put;
3534         }
3535
3536         /*
3537          * We want to set the generation to 0, that way if anything goes wrong
3538          * from here on out we know not to trust this cache when we load up next
3539          * time.
3540          */
3541         BTRFS_I(inode)->generation = 0;
3542         ret = btrfs_update_inode(trans, root, inode);
3543         if (ret) {
3544                 /*
3545                  * So theoretically we could recover from this, simply set the
3546                  * super cache generation to 0 so we know to invalidate the
3547                  * cache, but then we'd have to keep track of the block groups
3548                  * that fail this way so we know we _have_ to reset this cache
3549                  * before the next commit or risk reading stale cache.  So to
3550                  * limit our exposure to horrible edge cases lets just abort the
3551                  * transaction, this only happens in really bad situations
3552                  * anyway.
3553                  */
3554                 btrfs_abort_transaction(trans, ret);
3555                 goto out_put;
3556         }
3557         WARN_ON(ret);
3558
3559         if (i_size_read(inode) > 0) {
3560                 ret = btrfs_check_trunc_cache_free_space(fs_info,
3561                                         &fs_info->global_block_rsv);
3562                 if (ret)
3563                         goto out_put;
3564
3565                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3566                 if (ret)
3567                         goto out_put;
3568         }
3569
3570         spin_lock(&block_group->lock);
3571         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3572             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3573                 /*
3574                  * don't bother trying to write stuff out _if_
3575                  * a) we're not cached,
3576                  * b) we're with nospace_cache mount option,
3577                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
3578                  */
3579                 dcs = BTRFS_DC_WRITTEN;
3580                 spin_unlock(&block_group->lock);
3581                 goto out_put;
3582         }
3583         spin_unlock(&block_group->lock);
3584
3585         /*
3586          * We hit an ENOSPC when setting up the cache in this transaction, just
3587          * skip doing the setup, we've already cleared the cache so we're safe.
3588          */
3589         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3590                 ret = -ENOSPC;
3591                 goto out_put;
3592         }
3593
3594         /*
3595          * Try to preallocate enough space based on how big the block group is.
3596          * Keep in mind this has to include any pinned space which could end up
3597          * taking up quite a bit since it's not folded into the other space
3598          * cache.
3599          */
3600         num_pages = div_u64(block_group->key.offset, SZ_256M);
3601         if (!num_pages)
3602                 num_pages = 1;
3603
3604         num_pages *= 16;
3605         num_pages *= PAGE_SIZE;
3606
3607         ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
3608         if (ret)
3609                 goto out_put;
3610
3611         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3612                                               num_pages, num_pages,
3613                                               &alloc_hint);
3614         /*
3615          * Our cache requires contiguous chunks so that we don't modify a bunch
3616          * of metadata or split extents when writing the cache out, which means
3617          * we can enospc if we are heavily fragmented in addition to just normal
3618          * out of space conditions.  So if we hit this just skip setting up any
3619          * other block groups for this transaction, maybe we'll unpin enough
3620          * space the next time around.
3621          */
3622         if (!ret)
3623                 dcs = BTRFS_DC_SETUP;
3624         else if (ret == -ENOSPC)
3625                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3626
3627 out_put:
3628         iput(inode);
3629 out_free:
3630         btrfs_release_path(path);
3631 out:
3632         spin_lock(&block_group->lock);
3633         if (!ret && dcs == BTRFS_DC_SETUP)
3634                 block_group->cache_generation = trans->transid;
3635         block_group->disk_cache_state = dcs;
3636         spin_unlock(&block_group->lock);
3637
3638         extent_changeset_free(data_reserved);
3639         return ret;
3640 }
3641
3642 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3643                             struct btrfs_fs_info *fs_info)
3644 {
3645         struct btrfs_block_group_cache *cache, *tmp;
3646         struct btrfs_transaction *cur_trans = trans->transaction;
3647         struct btrfs_path *path;
3648
3649         if (list_empty(&cur_trans->dirty_bgs) ||
3650             !btrfs_test_opt(fs_info, SPACE_CACHE))
3651                 return 0;
3652
3653         path = btrfs_alloc_path();
3654         if (!path)
3655                 return -ENOMEM;
3656
3657         /* Could add new block groups, use _safe just in case */
3658         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3659                                  dirty_list) {
3660                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3661                         cache_save_setup(cache, trans, path);
3662         }
3663
3664         btrfs_free_path(path);
3665         return 0;
3666 }
3667
3668 /*
3669  * transaction commit does final block group cache writeback during a
3670  * critical section where nothing is allowed to change the FS.  This is
3671  * required in order for the cache to actually match the block group,
3672  * but can introduce a lot of latency into the commit.
3673  *
3674  * So, btrfs_start_dirty_block_groups is here to kick off block group
3675  * cache IO.  There's a chance we'll have to redo some of it if the
3676  * block group changes again during the commit, but it greatly reduces
3677  * the commit latency by getting rid of the easy block groups while
3678  * we're still allowing others to join the commit.
3679  */
3680 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3681                                    struct btrfs_fs_info *fs_info)
3682 {
3683         struct btrfs_block_group_cache *cache;
3684         struct btrfs_transaction *cur_trans = trans->transaction;
3685         int ret = 0;
3686         int should_put;
3687         struct btrfs_path *path = NULL;
3688         LIST_HEAD(dirty);
3689         struct list_head *io = &cur_trans->io_bgs;
3690         int num_started = 0;
3691         int loops = 0;
3692
3693         spin_lock(&cur_trans->dirty_bgs_lock);
3694         if (list_empty(&cur_trans->dirty_bgs)) {
3695                 spin_unlock(&cur_trans->dirty_bgs_lock);
3696                 return 0;
3697         }
3698         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3699         spin_unlock(&cur_trans->dirty_bgs_lock);
3700
3701 again:
3702         /*
3703          * make sure all the block groups on our dirty list actually
3704          * exist
3705          */
3706         btrfs_create_pending_block_groups(trans, fs_info);
3707
3708         if (!path) {
3709                 path = btrfs_alloc_path();
3710                 if (!path)
3711                         return -ENOMEM;
3712         }
3713
3714         /*
3715          * cache_write_mutex is here only to save us from balance or automatic
3716          * removal of empty block groups deleting this block group while we are
3717          * writing out the cache
3718          */
3719         mutex_lock(&trans->transaction->cache_write_mutex);
3720         while (!list_empty(&dirty)) {
3721                 cache = list_first_entry(&dirty,
3722                                          struct btrfs_block_group_cache,
3723                                          dirty_list);
3724                 /*
3725                  * this can happen if something re-dirties a block
3726                  * group that is already under IO.  Just wait for it to
3727                  * finish and then do it all again
3728                  */
3729                 if (!list_empty(&cache->io_list)) {
3730                         list_del_init(&cache->io_list);
3731                         btrfs_wait_cache_io(trans, cache, path);
3732                         btrfs_put_block_group(cache);
3733                 }
3734
3735
3736                 /*
3737                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3738                  * if it should update the cache_state.  Don't delete
3739                  * until after we wait.
3740                  *
3741                  * Since we're not running in the commit critical section
3742                  * we need the dirty_bgs_lock to protect from update_block_group
3743                  */
3744                 spin_lock(&cur_trans->dirty_bgs_lock);
3745                 list_del_init(&cache->dirty_list);
3746                 spin_unlock(&cur_trans->dirty_bgs_lock);
3747
3748                 should_put = 1;
3749
3750                 cache_save_setup(cache, trans, path);
3751
3752                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3753                         cache->io_ctl.inode = NULL;
3754                         ret = btrfs_write_out_cache(fs_info, trans,
3755                                                     cache, path);
3756                         if (ret == 0 && cache->io_ctl.inode) {
3757                                 num_started++;
3758                                 should_put = 0;
3759
3760                                 /*
3761                                  * the cache_write_mutex is protecting
3762                                  * the io_list
3763                                  */
3764                                 list_add_tail(&cache->io_list, io);
3765                         } else {
3766                                 /*
3767                                  * if we failed to write the cache, the
3768                                  * generation will be bad and life goes on
3769                                  */
3770                                 ret = 0;
3771                         }
3772                 }
3773                 if (!ret) {
3774                         ret = write_one_cache_group(trans, fs_info,
3775                                                     path, cache);
3776                         /*
3777                          * Our block group might still be attached to the list
3778                          * of new block groups in the transaction handle of some
3779                          * other task (struct btrfs_trans_handle->new_bgs). This
3780                          * means its block group item isn't yet in the extent
3781                          * tree. If this happens ignore the error, as we will
3782                          * try again later in the critical section of the
3783                          * transaction commit.
3784                          */
3785                         if (ret == -ENOENT) {
3786                                 ret = 0;
3787                                 spin_lock(&cur_trans->dirty_bgs_lock);
3788                                 if (list_empty(&cache->dirty_list)) {
3789                                         list_add_tail(&cache->dirty_list,
3790                                                       &cur_trans->dirty_bgs);
3791                                         btrfs_get_block_group(cache);
3792                                 }
3793                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3794                         } else if (ret) {
3795                                 btrfs_abort_transaction(trans, ret);
3796                         }
3797                 }
3798
3799                 /* if its not on the io list, we need to put the block group */
3800                 if (should_put)
3801                         btrfs_put_block_group(cache);
3802
3803                 if (ret)
3804                         break;
3805
3806                 /*
3807                  * Avoid blocking other tasks for too long. It might even save
3808                  * us from writing caches for block groups that are going to be
3809                  * removed.
3810                  */
3811                 mutex_unlock(&trans->transaction->cache_write_mutex);
3812                 mutex_lock(&trans->transaction->cache_write_mutex);
3813         }
3814         mutex_unlock(&trans->transaction->cache_write_mutex);
3815
3816         /*
3817          * go through delayed refs for all the stuff we've just kicked off
3818          * and then loop back (just once)
3819          */
3820         ret = btrfs_run_delayed_refs(trans, fs_info, 0);
3821         if (!ret && loops == 0) {
3822                 loops++;
3823                 spin_lock(&cur_trans->dirty_bgs_lock);
3824                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3825                 /*
3826                  * dirty_bgs_lock protects us from concurrent block group
3827                  * deletes too (not just cache_write_mutex).
3828                  */
3829                 if (!list_empty(&dirty)) {
3830                         spin_unlock(&cur_trans->dirty_bgs_lock);
3831                         goto again;
3832                 }
3833                 spin_unlock(&cur_trans->dirty_bgs_lock);
3834         } else if (ret < 0) {
3835                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3836         }
3837
3838         btrfs_free_path(path);
3839         return ret;
3840 }
3841
3842 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3843                                    struct btrfs_fs_info *fs_info)
3844 {
3845         struct btrfs_block_group_cache *cache;
3846         struct btrfs_transaction *cur_trans = trans->transaction;
3847         int ret = 0;
3848         int should_put;
3849         struct btrfs_path *path;
3850         struct list_head *io = &cur_trans->io_bgs;
3851         int num_started = 0;
3852
3853         path = btrfs_alloc_path();
3854         if (!path)
3855                 return -ENOMEM;
3856
3857         /*
3858          * Even though we are in the critical section of the transaction commit,
3859          * we can still have concurrent tasks adding elements to this
3860          * transaction's list of dirty block groups. These tasks correspond to
3861          * endio free space workers started when writeback finishes for a
3862          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3863          * allocate new block groups as a result of COWing nodes of the root
3864          * tree when updating the free space inode. The writeback for the space
3865          * caches is triggered by an earlier call to
3866          * btrfs_start_dirty_block_groups() and iterations of the following
3867          * loop.
3868          * Also we want to do the cache_save_setup first and then run the
3869          * delayed refs to make sure we have the best chance at doing this all
3870          * in one shot.
3871          */
3872         spin_lock(&cur_trans->dirty_bgs_lock);
3873         while (!list_empty(&cur_trans->dirty_bgs)) {
3874                 cache = list_first_entry(&cur_trans->dirty_bgs,
3875                                          struct btrfs_block_group_cache,
3876                                          dirty_list);
3877
3878                 /*
3879                  * this can happen if cache_save_setup re-dirties a block
3880                  * group that is already under IO.  Just wait for it to
3881                  * finish and then do it all again
3882                  */
3883                 if (!list_empty(&cache->io_list)) {
3884                         spin_unlock(&cur_trans->dirty_bgs_lock);
3885                         list_del_init(&cache->io_list);
3886                         btrfs_wait_cache_io(trans, cache, path);
3887                         btrfs_put_block_group(cache);
3888                         spin_lock(&cur_trans->dirty_bgs_lock);
3889                 }
3890
3891                 /*
3892                  * don't remove from the dirty list until after we've waited
3893                  * on any pending IO
3894                  */
3895                 list_del_init(&cache->dirty_list);
3896                 spin_unlock(&cur_trans->dirty_bgs_lock);
3897                 should_put = 1;
3898
3899                 cache_save_setup(cache, trans, path);
3900
3901                 if (!ret)
3902                         ret = btrfs_run_delayed_refs(trans, fs_info,
3903                                                      (unsigned long) -1);
3904
3905                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3906                         cache->io_ctl.inode = NULL;
3907                         ret = btrfs_write_out_cache(fs_info, trans,
3908                                                     cache, path);
3909                         if (ret == 0 && cache->io_ctl.inode) {
3910                                 num_started++;
3911                                 should_put = 0;
3912                                 list_add_tail(&cache->io_list, io);
3913                         } else {
3914                                 /*
3915                                  * if we failed to write the cache, the
3916                                  * generation will be bad and life goes on
3917                                  */
3918                                 ret = 0;
3919                         }
3920                 }
3921                 if (!ret) {
3922                         ret = write_one_cache_group(trans, fs_info,
3923                                                     path, cache);
3924                         /*
3925                          * One of the free space endio workers might have
3926                          * created a new block group while updating a free space
3927                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3928                          * and hasn't released its transaction handle yet, in
3929                          * which case the new block group is still attached to
3930                          * its transaction handle and its creation has not
3931                          * finished yet (no block group item in the extent tree
3932                          * yet, etc). If this is the case, wait for all free
3933                          * space endio workers to finish and retry. This is a
3934                          * a very rare case so no need for a more efficient and
3935                          * complex approach.
3936                          */
3937                         if (ret == -ENOENT) {
3938                                 wait_event(cur_trans->writer_wait,
3939                                    atomic_read(&cur_trans->num_writers) == 1);
3940                                 ret = write_one_cache_group(trans, fs_info,
3941                                                             path, cache);
3942                         }
3943                         if (ret)
3944                                 btrfs_abort_transaction(trans, ret);
3945                 }
3946
3947                 /* if its not on the io list, we need to put the block group */
3948                 if (should_put)
3949                         btrfs_put_block_group(cache);
3950                 spin_lock(&cur_trans->dirty_bgs_lock);
3951         }
3952         spin_unlock(&cur_trans->dirty_bgs_lock);
3953
3954         while (!list_empty(io)) {
3955                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3956                                          io_list);
3957                 list_del_init(&cache->io_list);
3958                 btrfs_wait_cache_io(trans, cache, path);
3959                 btrfs_put_block_group(cache);
3960         }
3961
3962         btrfs_free_path(path);
3963         return ret;
3964 }
3965
3966 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
3967 {
3968         struct btrfs_block_group_cache *block_group;
3969         int readonly = 0;
3970
3971         block_group = btrfs_lookup_block_group(fs_info, bytenr);
3972         if (!block_group || block_group->ro)
3973                 readonly = 1;
3974         if (block_group)
3975                 btrfs_put_block_group(block_group);
3976         return readonly;
3977 }
3978
3979 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3980 {
3981         struct btrfs_block_group_cache *bg;
3982         bool ret = true;
3983
3984         bg = btrfs_lookup_block_group(fs_info, bytenr);
3985         if (!bg)
3986                 return false;
3987
3988         spin_lock(&bg->lock);
3989         if (bg->ro)
3990                 ret = false;
3991         else
3992                 atomic_inc(&bg->nocow_writers);
3993         spin_unlock(&bg->lock);
3994
3995         /* no put on block group, done by btrfs_dec_nocow_writers */
3996         if (!ret)
3997                 btrfs_put_block_group(bg);
3998
3999         return ret;
4000
4001 }
4002
4003 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
4004 {
4005         struct btrfs_block_group_cache *bg;
4006
4007         bg = btrfs_lookup_block_group(fs_info, bytenr);
4008         ASSERT(bg);
4009         if (atomic_dec_and_test(&bg->nocow_writers))
4010                 wake_up_atomic_t(&bg->nocow_writers);
4011         /*
4012          * Once for our lookup and once for the lookup done by a previous call
4013          * to btrfs_inc_nocow_writers()
4014          */
4015         btrfs_put_block_group(bg);
4016         btrfs_put_block_group(bg);
4017 }
4018
4019 static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a)
4020 {
4021         schedule();
4022         return 0;
4023 }
4024
4025 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
4026 {
4027         wait_on_atomic_t(&bg->nocow_writers,
4028                          btrfs_wait_nocow_writers_atomic_t,
4029                          TASK_UNINTERRUPTIBLE);
4030 }
4031
4032 static const char *alloc_name(u64 flags)
4033 {
4034         switch (flags) {
4035         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
4036                 return "mixed";
4037         case BTRFS_BLOCK_GROUP_METADATA:
4038                 return "metadata";
4039         case BTRFS_BLOCK_GROUP_DATA:
4040                 return "data";
4041         case BTRFS_BLOCK_GROUP_SYSTEM:
4042                 return "system";
4043         default:
4044                 WARN_ON(1);
4045                 return "invalid-combination";
4046         };
4047 }
4048
4049 static int create_space_info(struct btrfs_fs_info *info, u64 flags,
4050                              struct btrfs_space_info **new)
4051 {
4052
4053         struct btrfs_space_info *space_info;
4054         int i;
4055         int ret;
4056
4057         space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
4058         if (!space_info)
4059                 return -ENOMEM;
4060
4061         ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
4062                                  GFP_KERNEL);
4063         if (ret) {
4064                 kfree(space_info);
4065                 return ret;
4066         }
4067
4068         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
4069                 INIT_LIST_HEAD(&space_info->block_groups[i]);
4070         init_rwsem(&space_info->groups_sem);
4071         spin_lock_init(&space_info->lock);
4072         space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
4073         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4074         init_waitqueue_head(&space_info->wait);
4075         INIT_LIST_HEAD(&space_info->ro_bgs);
4076         INIT_LIST_HEAD(&space_info->tickets);
4077         INIT_LIST_HEAD(&space_info->priority_tickets);
4078
4079         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
4080                                     info->space_info_kobj, "%s",
4081                                     alloc_name(space_info->flags));
4082         if (ret) {
4083                 percpu_counter_destroy(&space_info->total_bytes_pinned);
4084                 kfree(space_info);
4085                 return ret;
4086         }
4087
4088         *new = space_info;
4089         list_add_rcu(&space_info->list, &info->space_info);
4090         if (flags & BTRFS_BLOCK_GROUP_DATA)
4091                 info->data_sinfo = space_info;
4092
4093         return ret;
4094 }
4095
4096 static void update_space_info(struct btrfs_fs_info *info, u64 flags,
4097                              u64 total_bytes, u64 bytes_used,
4098                              u64 bytes_readonly,
4099                              struct btrfs_space_info **space_info)
4100 {
4101         struct btrfs_space_info *found;
4102         int factor;
4103
4104         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
4105                      BTRFS_BLOCK_GROUP_RAID10))
4106                 factor = 2;
4107         else
4108                 factor = 1;
4109
4110         found = __find_space_info(info, flags);
4111         ASSERT(found);
4112         spin_lock(&found->lock);
4113         found->total_bytes += total_bytes;
4114         found->disk_total += total_bytes * factor;
4115         found->bytes_used += bytes_used;
4116         found->disk_used += bytes_used * factor;
4117         found->bytes_readonly += bytes_readonly;
4118         if (total_bytes > 0)
4119                 found->full = 0;
4120         space_info_add_new_bytes(info, found, total_bytes -
4121                                  bytes_used - bytes_readonly);
4122         spin_unlock(&found->lock);
4123         *space_info = found;
4124 }
4125
4126 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
4127 {
4128         u64 extra_flags = chunk_to_extended(flags) &
4129                                 BTRFS_EXTENDED_PROFILE_MASK;
4130
4131         write_seqlock(&fs_info->profiles_lock);
4132         if (flags & BTRFS_BLOCK_GROUP_DATA)
4133                 fs_info->avail_data_alloc_bits |= extra_flags;
4134         if (flags & BTRFS_BLOCK_GROUP_METADATA)
4135                 fs_info->avail_metadata_alloc_bits |= extra_flags;
4136         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4137                 fs_info->avail_system_alloc_bits |= extra_flags;
4138         write_sequnlock(&fs_info->profiles_lock);
4139 }
4140
4141 /*
4142  * returns target flags in extended format or 0 if restripe for this
4143  * chunk_type is not in progress
4144  *
4145  * should be called with either volume_mutex or balance_lock held
4146  */
4147 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4148 {
4149         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4150         u64 target = 0;
4151
4152         if (!bctl)
4153                 return 0;
4154
4155         if (flags & BTRFS_BLOCK_GROUP_DATA &&
4156             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4157                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4158         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4159                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4160                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4161         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4162                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4163                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4164         }
4165
4166         return target;
4167 }
4168
4169 /*
4170  * @flags: available profiles in extended format (see ctree.h)
4171  *
4172  * Returns reduced profile in chunk format.  If profile changing is in
4173  * progress (either running or paused) picks the target profile (if it's
4174  * already available), otherwise falls back to plain reducing.
4175  */
4176 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
4177 {
4178         u64 num_devices = fs_info->fs_devices->rw_devices;
4179         u64 target;
4180         u64 raid_type;
4181         u64 allowed = 0;
4182
4183         /*
4184          * see if restripe for this chunk_type is in progress, if so
4185          * try to reduce to the target profile
4186          */
4187         spin_lock(&fs_info->balance_lock);
4188         target = get_restripe_target(fs_info, flags);
4189         if (target) {
4190                 /* pick target profile only if it's already available */
4191                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4192                         spin_unlock(&fs_info->balance_lock);
4193                         return extended_to_chunk(target);
4194                 }
4195         }
4196         spin_unlock(&fs_info->balance_lock);
4197
4198         /* First, mask out the RAID levels which aren't possible */
4199         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4200                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4201                         allowed |= btrfs_raid_group[raid_type];
4202         }
4203         allowed &= flags;
4204
4205         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4206                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4207         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4208                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4209         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4210                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4211         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4212                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4213         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4214                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4215
4216         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4217
4218         return extended_to_chunk(flags | allowed);
4219 }
4220
4221 static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
4222 {
4223         unsigned seq;
4224         u64 flags;
4225
4226         do {
4227                 flags = orig_flags;
4228                 seq = read_seqbegin(&fs_info->profiles_lock);
4229
4230                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4231                         flags |= fs_info->avail_data_alloc_bits;
4232                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4233                         flags |= fs_info->avail_system_alloc_bits;
4234                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4235                         flags |= fs_info->avail_metadata_alloc_bits;
4236         } while (read_seqretry(&fs_info->profiles_lock, seq));
4237
4238         return btrfs_reduce_alloc_profile(fs_info, flags);
4239 }
4240
4241 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
4242 {
4243         struct btrfs_fs_info *fs_info = root->fs_info;
4244         u64 flags;
4245         u64 ret;
4246
4247         if (data)
4248                 flags = BTRFS_BLOCK_GROUP_DATA;
4249         else if (root == fs_info->chunk_root)
4250                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4251         else
4252                 flags = BTRFS_BLOCK_GROUP_METADATA;
4253
4254         ret = get_alloc_profile(fs_info, flags);
4255         return ret;
4256 }
4257
4258 u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
4259 {
4260         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
4261 }
4262
4263 u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
4264 {
4265         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4266 }
4267
4268 u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
4269 {
4270         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4271 }
4272
4273 static u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
4274                                  bool may_use_included)
4275 {
4276         ASSERT(s_info);
4277         return s_info->bytes_used + s_info->bytes_reserved +
4278                 s_info->bytes_pinned + s_info->bytes_readonly +
4279                 (may_use_included ? s_info->bytes_may_use : 0);
4280 }
4281
4282 int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes)
4283 {
4284         struct btrfs_root *root = inode->root;
4285         struct btrfs_fs_info *fs_info = root->fs_info;
4286         struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
4287         u64 used;
4288         int ret = 0;
4289         int need_commit = 2;
4290         int have_pinned_space;
4291
4292         /* make sure bytes are sectorsize aligned */
4293         bytes = ALIGN(bytes, fs_info->sectorsize);
4294
4295         if (btrfs_is_free_space_inode(inode)) {
4296                 need_commit = 0;
4297                 ASSERT(current->journal_info);
4298         }
4299
4300 again:
4301         /* make sure we have enough space to handle the data first */
4302         spin_lock(&data_sinfo->lock);
4303         used = btrfs_space_info_used(data_sinfo, true);
4304
4305         if (used + bytes > data_sinfo->total_bytes) {
4306                 struct btrfs_trans_handle *trans;
4307
4308                 /*
4309                  * if we don't have enough free bytes in this space then we need
4310                  * to alloc a new chunk.
4311                  */
4312                 if (!data_sinfo->full) {
4313                         u64 alloc_target;
4314
4315                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4316                         spin_unlock(&data_sinfo->lock);
4317
4318                         alloc_target = btrfs_data_alloc_profile(fs_info);
4319                         /*
4320                          * It is ugly that we don't call nolock join
4321                          * transaction for the free space inode case here.
4322                          * But it is safe because we only do the data space
4323                          * reservation for the free space cache in the
4324                          * transaction context, the common join transaction
4325                          * just increase the counter of the current transaction
4326                          * handler, doesn't try to acquire the trans_lock of
4327                          * the fs.
4328                          */
4329                         trans = btrfs_join_transaction(root);
4330                         if (IS_ERR(trans))
4331                                 return PTR_ERR(trans);
4332
4333                         ret = do_chunk_alloc(trans, fs_info, alloc_target,
4334                                              CHUNK_ALLOC_NO_FORCE);
4335                         btrfs_end_transaction(trans);
4336                         if (ret < 0) {
4337                                 if (ret != -ENOSPC)
4338                                         return ret;
4339                                 else {
4340                                         have_pinned_space = 1;
4341                                         goto commit_trans;
4342                                 }
4343                         }
4344
4345                         goto again;
4346                 }
4347
4348                 /*
4349                  * If we don't have enough pinned space to deal with this
4350                  * allocation, and no removed chunk in current transaction,
4351                  * don't bother committing the transaction.
4352                  */
4353                 have_pinned_space = percpu_counter_compare(
4354                         &data_sinfo->total_bytes_pinned,
4355                         used + bytes - data_sinfo->total_bytes);
4356                 spin_unlock(&data_sinfo->lock);
4357
4358                 /* commit the current transaction and try again */
4359 commit_trans:
4360                 if (need_commit &&
4361                     !atomic_read(&fs_info->open_ioctl_trans)) {
4362                         need_commit--;
4363
4364                         if (need_commit > 0) {
4365                                 btrfs_start_delalloc_roots(fs_info, 0, -1);
4366                                 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0,
4367                                                          (u64)-1);
4368                         }
4369
4370                         trans = btrfs_join_transaction(root);
4371                         if (IS_ERR(trans))
4372                                 return PTR_ERR(trans);
4373                         if (have_pinned_space >= 0 ||
4374                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4375                                      &trans->transaction->flags) ||
4376                             need_commit > 0) {
4377                                 ret = btrfs_commit_transaction(trans);
4378                                 if (ret)
4379                                         return ret;
4380                                 /*
4381                                  * The cleaner kthread might still be doing iput
4382                                  * operations. Wait for it to finish so that
4383                                  * more space is released.
4384                                  */
4385                                 mutex_lock(&fs_info->cleaner_delayed_iput_mutex);
4386                                 mutex_unlock(&fs_info->cleaner_delayed_iput_mutex);
4387                                 goto again;
4388                         } else {
4389                                 btrfs_end_transaction(trans);
4390                         }
4391                 }
4392
4393                 trace_btrfs_space_reservation(fs_info,
4394                                               "space_info:enospc",
4395                                               data_sinfo->flags, bytes, 1);
4396                 return -ENOSPC;
4397         }
4398         data_sinfo->bytes_may_use += bytes;
4399         trace_btrfs_space_reservation(fs_info, "space_info",
4400                                       data_sinfo->flags, bytes, 1);
4401         spin_unlock(&data_sinfo->lock);
4402
4403         return ret;
4404 }
4405
4406 int btrfs_check_data_free_space(struct inode *inode,
4407                         struct extent_changeset **reserved, u64 start, u64 len)
4408 {
4409         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4410         int ret;
4411
4412         /* align the range */
4413         len = round_up(start + len, fs_info->sectorsize) -
4414               round_down(start, fs_info->sectorsize);
4415         start = round_down(start, fs_info->sectorsize);
4416
4417         ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), len);
4418         if (ret < 0)
4419                 return ret;
4420
4421         /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4422         ret = btrfs_qgroup_reserve_data(inode, reserved, start, len);
4423         if (ret < 0)
4424                 btrfs_free_reserved_data_space_noquota(inode, start, len);
4425         else
4426                 ret = 0;
4427         return ret;
4428 }
4429
4430 /*
4431  * Called if we need to clear a data reservation for this inode
4432  * Normally in a error case.
4433  *
4434  * This one will *NOT* use accurate qgroup reserved space API, just for case
4435  * which we can't sleep and is sure it won't affect qgroup reserved space.
4436  * Like clear_bit_hook().
4437  */
4438 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4439                                             u64 len)
4440 {
4441         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4442         struct btrfs_space_info *data_sinfo;
4443
4444         /* Make sure the range is aligned to sectorsize */
4445         len = round_up(start + len, fs_info->sectorsize) -
4446               round_down(start, fs_info->sectorsize);
4447         start = round_down(start, fs_info->sectorsize);
4448
4449         data_sinfo = fs_info->data_sinfo;
4450         spin_lock(&data_sinfo->lock);
4451         if (WARN_ON(data_sinfo->bytes_may_use < len))
4452                 data_sinfo->bytes_may_use = 0;
4453         else
4454                 data_sinfo->bytes_may_use -= len;
4455         trace_btrfs_space_reservation(fs_info, "space_info",
4456                                       data_sinfo->flags, len, 0);
4457         spin_unlock(&data_sinfo->lock);
4458 }
4459
4460 /*
4461  * Called if we need to clear a data reservation for this inode
4462  * Normally in a error case.
4463  *
4464  * This one will handle the per-inode data rsv map for accurate reserved
4465  * space framework.
4466  */
4467 void btrfs_free_reserved_data_space(struct inode *inode,
4468                         struct extent_changeset *reserved, u64 start, u64 len)
4469 {
4470         struct btrfs_root *root = BTRFS_I(inode)->root;
4471
4472         /* Make sure the range is aligned to sectorsize */
4473         len = round_up(start + len, root->fs_info->sectorsize) -
4474               round_down(start, root->fs_info->sectorsize);
4475         start = round_down(start, root->fs_info->sectorsize);
4476
4477         btrfs_free_reserved_data_space_noquota(inode, start, len);
4478         btrfs_qgroup_free_data(inode, reserved, start, len);
4479 }
4480
4481 static void force_metadata_allocation(struct btrfs_fs_info *info)
4482 {
4483         struct list_head *head = &info->space_info;
4484         struct btrfs_space_info *found;
4485
4486         rcu_read_lock();
4487         list_for_each_entry_rcu(found, head, list) {
4488                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4489                         found->force_alloc = CHUNK_ALLOC_FORCE;
4490         }
4491         rcu_read_unlock();
4492 }
4493
4494 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4495 {
4496         return (global->size << 1);
4497 }
4498
4499 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
4500                               struct btrfs_space_info *sinfo, int force)
4501 {
4502         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4503         u64 bytes_used = btrfs_space_info_used(sinfo, false);
4504         u64 thresh;
4505
4506         if (force == CHUNK_ALLOC_FORCE)
4507                 return 1;
4508
4509         /*
4510          * We need to take into account the global rsv because for all intents
4511          * and purposes it's used space.  Don't worry about locking the
4512          * global_rsv, it doesn't change except when the transaction commits.
4513          */
4514         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4515                 bytes_used += calc_global_rsv_need_space(global_rsv);
4516
4517         /*
4518          * in limited mode, we want to have some free space up to
4519          * about 1% of the FS size.
4520          */
4521         if (force == CHUNK_ALLOC_LIMITED) {
4522                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
4523                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4524
4525                 if (sinfo->total_bytes - bytes_used < thresh)
4526                         return 1;
4527         }
4528
4529         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
4530                 return 0;
4531         return 1;
4532 }
4533
4534 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4535 {
4536         u64 num_dev;
4537
4538         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4539                     BTRFS_BLOCK_GROUP_RAID0 |
4540                     BTRFS_BLOCK_GROUP_RAID5 |
4541                     BTRFS_BLOCK_GROUP_RAID6))
4542                 num_dev = fs_info->fs_devices->rw_devices;
4543         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4544                 num_dev = 2;
4545         else
4546                 num_dev = 1;    /* DUP or single */
4547
4548         return num_dev;
4549 }
4550
4551 /*
4552  * If @is_allocation is true, reserve space in the system space info necessary
4553  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4554  * removing a chunk.
4555  */
4556 void check_system_chunk(struct btrfs_trans_handle *trans,
4557                         struct btrfs_fs_info *fs_info, u64 type)
4558 {
4559         struct btrfs_space_info *info;
4560         u64 left;
4561         u64 thresh;
4562         int ret = 0;
4563         u64 num_devs;
4564
4565         /*
4566          * Needed because we can end up allocating a system chunk and for an
4567          * atomic and race free space reservation in the chunk block reserve.
4568          */
4569         ASSERT(mutex_is_locked(&fs_info->chunk_mutex));
4570
4571         info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4572         spin_lock(&info->lock);
4573         left = info->total_bytes - btrfs_space_info_used(info, true);
4574         spin_unlock(&info->lock);
4575
4576         num_devs = get_profile_num_devs(fs_info, type);
4577
4578         /* num_devs device items to update and 1 chunk item to add or remove */
4579         thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
4580                 btrfs_calc_trans_metadata_size(fs_info, 1);
4581
4582         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4583                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4584                            left, thresh, type);
4585                 dump_space_info(fs_info, info, 0, 0);
4586         }
4587
4588         if (left < thresh) {
4589                 u64 flags = btrfs_system_alloc_profile(fs_info);
4590
4591                 /*
4592                  * Ignore failure to create system chunk. We might end up not
4593                  * needing it, as we might not need to COW all nodes/leafs from
4594                  * the paths we visit in the chunk tree (they were already COWed
4595                  * or created in the current transaction for example).
4596                  */
4597                 ret = btrfs_alloc_chunk(trans, fs_info, flags);
4598         }
4599
4600         if (!ret) {
4601                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
4602                                           &fs_info->chunk_block_rsv,
4603                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4604                 if (!ret)
4605                         trans->chunk_bytes_reserved += thresh;
4606         }
4607 }
4608
4609 /*
4610  * If force is CHUNK_ALLOC_FORCE:
4611  *    - return 1 if it successfully allocates a chunk,
4612  *    - return errors including -ENOSPC otherwise.
4613  * If force is NOT CHUNK_ALLOC_FORCE:
4614  *    - return 0 if it doesn't need to allocate a new chunk,
4615  *    - return 1 if it successfully allocates a chunk,
4616  *    - return errors including -ENOSPC otherwise.
4617  */
4618 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4619                           struct btrfs_fs_info *fs_info, u64 flags, int force)
4620 {
4621         struct btrfs_space_info *space_info;
4622         int wait_for_alloc = 0;
4623         int ret = 0;
4624
4625         /* Don't re-enter if we're already allocating a chunk */
4626         if (trans->allocating_chunk)
4627                 return -ENOSPC;
4628
4629         space_info = __find_space_info(fs_info, flags);
4630         if (!space_info) {
4631                 ret = create_space_info(fs_info, flags, &space_info);
4632                 if (ret)
4633                         return ret;
4634         }
4635
4636 again:
4637         spin_lock(&space_info->lock);
4638         if (force < space_info->force_alloc)
4639                 force = space_info->force_alloc;
4640         if (space_info->full) {
4641                 if (should_alloc_chunk(fs_info, space_info, force))
4642                         ret = -ENOSPC;
4643                 else
4644                         ret = 0;
4645                 spin_unlock(&space_info->lock);
4646                 return ret;
4647         }
4648
4649         if (!should_alloc_chunk(fs_info, space_info, force)) {
4650                 spin_unlock(&space_info->lock);
4651                 return 0;
4652         } else if (space_info->chunk_alloc) {
4653                 wait_for_alloc = 1;
4654         } else {
4655                 space_info->chunk_alloc = 1;
4656         }
4657
4658         spin_unlock(&space_info->lock);
4659
4660         mutex_lock(&fs_info->chunk_mutex);
4661
4662         /*
4663          * The chunk_mutex is held throughout the entirety of a chunk
4664          * allocation, so once we've acquired the chunk_mutex we know that the
4665          * other guy is done and we need to recheck and see if we should
4666          * allocate.
4667          */
4668         if (wait_for_alloc) {
4669                 mutex_unlock(&fs_info->chunk_mutex);
4670                 wait_for_alloc = 0;
4671                 goto again;
4672         }
4673
4674         trans->allocating_chunk = true;
4675
4676         /*
4677          * If we have mixed data/metadata chunks we want to make sure we keep
4678          * allocating mixed chunks instead of individual chunks.
4679          */
4680         if (btrfs_mixed_space_info(space_info))
4681                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4682
4683         /*
4684          * if we're doing a data chunk, go ahead and make sure that
4685          * we keep a reasonable number of metadata chunks allocated in the
4686          * FS as well.
4687          */
4688         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4689                 fs_info->data_chunk_allocations++;
4690                 if (!(fs_info->data_chunk_allocations %
4691                       fs_info->metadata_ratio))
4692                         force_metadata_allocation(fs_info);
4693         }
4694
4695         /*
4696          * Check if we have enough space in SYSTEM chunk because we may need
4697          * to update devices.
4698          */
4699         check_system_chunk(trans, fs_info, flags);
4700
4701         ret = btrfs_alloc_chunk(trans, fs_info, flags);
4702         trans->allocating_chunk = false;
4703
4704         spin_lock(&space_info->lock);
4705         if (ret < 0 && ret != -ENOSPC)
4706                 goto out;
4707         if (ret)
4708                 space_info->full = 1;
4709         else
4710                 ret = 1;
4711
4712         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4713 out:
4714         space_info->chunk_alloc = 0;
4715         spin_unlock(&space_info->lock);
4716         mutex_unlock(&fs_info->chunk_mutex);
4717         /*
4718          * When we allocate a new chunk we reserve space in the chunk block
4719          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4720          * add new nodes/leafs to it if we end up needing to do it when
4721          * inserting the chunk item and updating device items as part of the
4722          * second phase of chunk allocation, performed by
4723          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4724          * large number of new block groups to create in our transaction
4725          * handle's new_bgs list to avoid exhausting the chunk block reserve
4726          * in extreme cases - like having a single transaction create many new
4727          * block groups when starting to write out the free space caches of all
4728          * the block groups that were made dirty during the lifetime of the
4729          * transaction.
4730          */
4731         if (trans->can_flush_pending_bgs &&
4732             trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4733                 btrfs_create_pending_block_groups(trans, fs_info);
4734                 btrfs_trans_release_chunk_metadata(trans);
4735         }
4736         return ret;
4737 }
4738
4739 static int can_overcommit(struct btrfs_fs_info *fs_info,
4740                           struct btrfs_space_info *space_info, u64 bytes,
4741                           enum btrfs_reserve_flush_enum flush,
4742                           bool system_chunk)
4743 {
4744         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4745         u64 profile;
4746         u64 space_size;
4747         u64 avail;
4748         u64 used;
4749
4750         /* Don't overcommit when in mixed mode. */
4751         if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4752                 return 0;
4753
4754         if (system_chunk)
4755                 profile = btrfs_system_alloc_profile(fs_info);
4756         else
4757                 profile = btrfs_metadata_alloc_profile(fs_info);
4758
4759         used = btrfs_space_info_used(space_info, false);
4760
4761         /*
4762          * We only want to allow over committing if we have lots of actual space
4763          * free, but if we don't have enough space to handle the global reserve
4764          * space then we could end up having a real enospc problem when trying
4765          * to allocate a chunk or some other such important allocation.
4766          */
4767         spin_lock(&global_rsv->lock);
4768         space_size = calc_global_rsv_need_space(global_rsv);
4769         spin_unlock(&global_rsv->lock);
4770         if (used + space_size >= space_info->total_bytes)
4771                 return 0;
4772
4773         used += space_info->bytes_may_use;
4774
4775         avail = atomic64_read(&fs_info->free_chunk_space);
4776
4777         /*
4778          * If we have dup, raid1 or raid10 then only half of the free
4779          * space is actually useable.  For raid56, the space info used
4780          * doesn't include the parity drive, so we don't have to
4781          * change the math
4782          */
4783         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4784                        BTRFS_BLOCK_GROUP_RAID1 |
4785                        BTRFS_BLOCK_GROUP_RAID10))
4786                 avail >>= 1;
4787
4788         /*
4789          * If we aren't flushing all things, let us overcommit up to
4790          * 1/2th of the space. If we can flush, don't let us overcommit
4791          * too much, let it overcommit up to 1/8 of the space.
4792          */
4793         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4794                 avail >>= 3;
4795         else
4796                 avail >>= 1;
4797
4798         if (used + bytes < space_info->total_bytes + avail)
4799                 return 1;
4800         return 0;
4801 }
4802
4803 static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
4804                                          unsigned long nr_pages, int nr_items)
4805 {
4806         struct super_block *sb = fs_info->sb;
4807
4808         if (down_read_trylock(&sb->s_umount)) {
4809                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4810                 up_read(&sb->s_umount);
4811         } else {
4812                 /*
4813                  * We needn't worry the filesystem going from r/w to r/o though
4814                  * we don't acquire ->s_umount mutex, because the filesystem
4815                  * should guarantee the delalloc inodes list be empty after
4816                  * the filesystem is readonly(all dirty pages are written to
4817                  * the disk).
4818                  */
4819                 btrfs_start_delalloc_roots(fs_info, 0, nr_items);
4820                 if (!current->journal_info)
4821                         btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
4822         }
4823 }
4824
4825 static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
4826                                         u64 to_reclaim)
4827 {
4828         u64 bytes;
4829         u64 nr;
4830
4831         bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
4832         nr = div64_u64(to_reclaim, bytes);
4833         if (!nr)
4834                 nr = 1;
4835         return nr;
4836 }
4837
4838 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4839
4840 /*
4841  * shrink metadata reservation for delalloc
4842  */
4843 static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
4844                             u64 orig, bool wait_ordered)
4845 {
4846         struct btrfs_block_rsv *block_rsv;
4847         struct btrfs_space_info *space_info;
4848         struct btrfs_trans_handle *trans;
4849         u64 delalloc_bytes;
4850         u64 max_reclaim;
4851         u64 items;
4852         long time_left;
4853         unsigned long nr_pages;
4854         int loops;
4855         enum btrfs_reserve_flush_enum flush;
4856
4857         /* Calc the number of the pages we need flush for space reservation */
4858         items = calc_reclaim_items_nr(fs_info, to_reclaim);
4859         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4860
4861         trans = (struct btrfs_trans_handle *)current->journal_info;
4862         block_rsv = &fs_info->delalloc_block_rsv;
4863         space_info = block_rsv->space_info;
4864
4865         delalloc_bytes = percpu_counter_sum_positive(
4866                                                 &fs_info->delalloc_bytes);
4867         if (delalloc_bytes == 0) {
4868                 if (trans)
4869                         return;
4870                 if (wait_ordered)
4871                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4872                 return;
4873         }
4874
4875         loops = 0;
4876         while (delalloc_bytes && loops < 3) {
4877                 max_reclaim = min(delalloc_bytes, to_reclaim);
4878                 nr_pages = max_reclaim >> PAGE_SHIFT;
4879                 btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items);
4880                 /*
4881                  * We need to wait for the async pages to actually start before
4882                  * we do anything.
4883                  */
4884                 max_reclaim = atomic_read(&fs_info->async_delalloc_pages);
4885                 if (!max_reclaim)
4886                         goto skip_async;
4887
4888                 if (max_reclaim <= nr_pages)
4889                         max_reclaim = 0;
4890                 else
4891                         max_reclaim -= nr_pages;
4892
4893                 wait_event(fs_info->async_submit_wait,
4894                            atomic_read(&fs_info->async_delalloc_pages) <=
4895                            (int)max_reclaim);
4896 skip_async:
4897                 if (!trans)
4898                         flush = BTRFS_RESERVE_FLUSH_ALL;
4899                 else
4900                         flush = BTRFS_RESERVE_NO_FLUSH;
4901                 spin_lock(&space_info->lock);
4902                 if (list_empty(&space_info->tickets) &&
4903                     list_empty(&space_info->priority_tickets)) {
4904                         spin_unlock(&space_info->lock);
4905                         break;
4906                 }
4907                 spin_unlock(&space_info->lock);
4908
4909                 loops++;
4910                 if (wait_ordered && !trans) {
4911                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4912                 } else {
4913                         time_left = schedule_timeout_killable(1);
4914                         if (time_left)
4915                                 break;
4916                 }
4917                 delalloc_bytes = percpu_counter_sum_positive(
4918                                                 &fs_info->delalloc_bytes);
4919         }
4920 }
4921
4922 /**
4923  * maybe_commit_transaction - possibly commit the transaction if its ok to
4924  * @root - the root we're allocating for
4925  * @bytes - the number of bytes we want to reserve
4926  * @force - force the commit
4927  *
4928  * This will check to make sure that committing the transaction will actually
4929  * get us somewhere and then commit the transaction if it does.  Otherwise it
4930  * will return -ENOSPC.
4931  */
4932 static int may_commit_transaction(struct btrfs_fs_info *fs_info,
4933                                   struct btrfs_space_info *space_info,
4934                                   u64 bytes, int force)
4935 {
4936         struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
4937         struct btrfs_trans_handle *trans;
4938
4939         trans = (struct btrfs_trans_handle *)current->journal_info;
4940         if (trans)
4941                 return -EAGAIN;
4942
4943         if (force)
4944                 goto commit;
4945
4946         /* See if there is enough pinned space to make this reservation */
4947         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4948                                    bytes) >= 0)
4949                 goto commit;
4950
4951         /*
4952          * See if there is some space in the delayed insertion reservation for
4953          * this reservation.
4954          */
4955         if (space_info != delayed_rsv->space_info)
4956                 return -ENOSPC;
4957
4958         spin_lock(&delayed_rsv->lock);
4959         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4960                                    bytes - delayed_rsv->size) < 0) {
4961                 spin_unlock(&delayed_rsv->lock);
4962                 return -ENOSPC;
4963         }
4964         spin_unlock(&delayed_rsv->lock);
4965
4966 commit:
4967         trans = btrfs_join_transaction(fs_info->extent_root);
4968         if (IS_ERR(trans))
4969                 return -ENOSPC;
4970
4971         return btrfs_commit_transaction(trans);
4972 }
4973
4974 struct reserve_ticket {
4975         u64 bytes;
4976         int error;
4977         struct list_head list;
4978         wait_queue_head_t wait;
4979 };
4980
4981 /*
4982  * Try to flush some data based on policy set by @state. This is only advisory
4983  * and may fail for various reasons. The caller is supposed to examine the
4984  * state of @space_info to detect the outcome.
4985  */
4986 static void flush_space(struct btrfs_fs_info *fs_info,
4987                        struct btrfs_space_info *space_info, u64 num_bytes,
4988                        int state)
4989 {
4990         struct btrfs_root *root = fs_info->extent_root;
4991         struct btrfs_trans_handle *trans;
4992         int nr;
4993         int ret = 0;
4994
4995         switch (state) {
4996         case FLUSH_DELAYED_ITEMS_NR:
4997         case FLUSH_DELAYED_ITEMS:
4998                 if (state == FLUSH_DELAYED_ITEMS_NR)
4999                         nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
5000                 else
5001                         nr = -1;
5002
5003                 trans = btrfs_join_transaction(root);
5004                 if (IS_ERR(trans)) {
5005                         ret = PTR_ERR(trans);
5006                         break;
5007                 }
5008                 ret = btrfs_run_delayed_items_nr(trans, fs_info, nr);
5009                 btrfs_end_transaction(trans);
5010                 break;
5011         case FLUSH_DELALLOC:
5012         case FLUSH_DELALLOC_WAIT:
5013                 shrink_delalloc(fs_info, num_bytes * 2, num_bytes,
5014                                 state == FLUSH_DELALLOC_WAIT);
5015                 break;
5016         case ALLOC_CHUNK:
5017                 trans = btrfs_join_transaction(root);
5018                 if (IS_ERR(trans)) {
5019                         ret = PTR_ERR(trans);
5020                         break;
5021                 }
5022                 ret = do_chunk_alloc(trans, fs_info,
5023                                      btrfs_metadata_alloc_profile(fs_info),
5024                                      CHUNK_ALLOC_NO_FORCE);
5025                 btrfs_end_transaction(trans);
5026                 if (ret > 0 || ret == -ENOSPC)
5027                         ret = 0;
5028                 break;
5029         case COMMIT_TRANS:
5030                 ret = may_commit_transaction(fs_info, space_info,
5031                                              num_bytes, 0);
5032                 break;
5033         default:
5034                 ret = -ENOSPC;
5035                 break;
5036         }
5037
5038         trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
5039                                 ret);
5040         return;
5041 }
5042
5043 static inline u64
5044 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
5045                                  struct btrfs_space_info *space_info,
5046                                  bool system_chunk)
5047 {
5048         struct reserve_ticket *ticket;
5049         u64 used;
5050         u64 expected;
5051         u64 to_reclaim = 0;
5052
5053         list_for_each_entry(ticket, &space_info->tickets, list)
5054                 to_reclaim += ticket->bytes;
5055         list_for_each_entry(ticket, &space_info->priority_tickets, list)
5056                 to_reclaim += ticket->bytes;
5057         if (to_reclaim)
5058                 return to_reclaim;
5059
5060         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
5061         if (can_overcommit(fs_info, space_info, to_reclaim,
5062                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
5063                 return 0;
5064
5065         used = btrfs_space_info_used(space_info, true);
5066
5067         if (can_overcommit(fs_info, space_info, SZ_1M,
5068                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
5069                 expected = div_factor_fine(space_info->total_bytes, 95);
5070         else
5071                 expected = div_factor_fine(space_info->total_bytes, 90);
5072
5073         if (used > expected)
5074                 to_reclaim = used - expected;
5075         else
5076                 to_reclaim = 0;
5077         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
5078                                      space_info->bytes_reserved);
5079         return to_reclaim;
5080 }
5081
5082 static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
5083                                         struct btrfs_space_info *space_info,
5084                                         u64 used, bool system_chunk)
5085 {
5086         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
5087
5088         /* If we're just plain full then async reclaim just slows us down. */
5089         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
5090                 return 0;
5091
5092         if (!btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5093                                               system_chunk))
5094                 return 0;
5095
5096         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
5097                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
5098 }
5099
5100 static void wake_all_tickets(struct list_head *head)
5101 {
5102         struct reserve_ticket *ticket;
5103
5104         while (!list_empty(head)) {
5105                 ticket = list_first_entry(head, struct reserve_ticket, list);
5106                 list_del_init(&ticket->list);
5107                 ticket->error = -ENOSPC;
5108                 wake_up(&ticket->wait);
5109         }
5110 }
5111
5112 /*
5113  * This is for normal flushers, we can wait all goddamned day if we want to.  We
5114  * will loop and continuously try to flush as long as we are making progress.
5115  * We count progress as clearing off tickets each time we have to loop.
5116  */
5117 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
5118 {
5119         struct btrfs_fs_info *fs_info;
5120         struct btrfs_space_info *space_info;
5121         u64 to_reclaim;
5122         int flush_state;
5123         int commit_cycles = 0;
5124         u64 last_tickets_id;
5125
5126         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
5127         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5128
5129         spin_lock(&space_info->lock);
5130         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5131                                                       false);
5132         if (!to_reclaim) {
5133                 space_info->flush = 0;
5134                 spin_unlock(&space_info->lock);
5135                 return;
5136         }
5137         last_tickets_id = space_info->tickets_id;
5138         spin_unlock(&space_info->lock);
5139
5140         flush_state = FLUSH_DELAYED_ITEMS_NR;
5141         do {
5142                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5143                 spin_lock(&space_info->lock);
5144                 if (list_empty(&space_info->tickets)) {
5145                         space_info->flush = 0;
5146                         spin_unlock(&space_info->lock);
5147                         return;
5148                 }
5149                 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
5150                                                               space_info,
5151                                                               false);
5152                 if (last_tickets_id == space_info->tickets_id) {
5153                         flush_state++;
5154                 } else {
5155                         last_tickets_id = space_info->tickets_id;
5156                         flush_state = FLUSH_DELAYED_ITEMS_NR;
5157                         if (commit_cycles)
5158                                 commit_cycles--;
5159                 }
5160
5161                 if (flush_state > COMMIT_TRANS) {
5162                         commit_cycles++;
5163                         if (commit_cycles > 2) {
5164                                 wake_all_tickets(&space_info->tickets);
5165                                 space_info->flush = 0;
5166                         } else {
5167                                 flush_state = FLUSH_DELAYED_ITEMS_NR;
5168                         }
5169                 }
5170                 spin_unlock(&space_info->lock);
5171         } while (flush_state <= COMMIT_TRANS);
5172 }
5173
5174 void btrfs_init_async_reclaim_work(struct work_struct *work)
5175 {
5176         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5177 }
5178
5179 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5180                                             struct btrfs_space_info *space_info,
5181                                             struct reserve_ticket *ticket)
5182 {
5183         u64 to_reclaim;
5184         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5185
5186         spin_lock(&space_info->lock);
5187         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5188                                                       false);
5189         if (!to_reclaim) {
5190                 spin_unlock(&space_info->lock);
5191                 return;
5192         }
5193         spin_unlock(&space_info->lock);
5194
5195         do {
5196                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5197                 flush_state++;
5198                 spin_lock(&space_info->lock);
5199                 if (ticket->bytes == 0) {
5200                         spin_unlock(&space_info->lock);
5201                         return;
5202                 }
5203                 spin_unlock(&space_info->lock);
5204
5205                 /*
5206                  * Priority flushers can't wait on delalloc without
5207                  * deadlocking.
5208                  */
5209                 if (flush_state == FLUSH_DELALLOC ||
5210                     flush_state == FLUSH_DELALLOC_WAIT)
5211                         flush_state = ALLOC_CHUNK;
5212         } while (flush_state < COMMIT_TRANS);
5213 }
5214
5215 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5216                                struct btrfs_space_info *space_info,
5217                                struct reserve_ticket *ticket, u64 orig_bytes)
5218
5219 {
5220         DEFINE_WAIT(wait);
5221         int ret = 0;
5222
5223         spin_lock(&space_info->lock);
5224         while (ticket->bytes > 0 && ticket->error == 0) {
5225                 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5226                 if (ret) {
5227                         ret = -EINTR;
5228                         break;
5229                 }
5230                 spin_unlock(&space_info->lock);
5231
5232                 schedule();
5233
5234                 finish_wait(&ticket->wait, &wait);
5235                 spin_lock(&space_info->lock);
5236         }
5237         if (!ret)
5238                 ret = ticket->error;
5239         if (!list_empty(&ticket->list))
5240                 list_del_init(&ticket->list);
5241         if (ticket->bytes && ticket->bytes < orig_bytes) {
5242                 u64 num_bytes = orig_bytes - ticket->bytes;
5243                 space_info->bytes_may_use -= num_bytes;
5244                 trace_btrfs_space_reservation(fs_info, "space_info",
5245                                               space_info->flags, num_bytes, 0);
5246         }
5247         spin_unlock(&space_info->lock);
5248
5249         return ret;
5250 }
5251
5252 /**
5253  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5254  * @root - the root we're allocating for
5255  * @space_info - the space info we want to allocate from
5256  * @orig_bytes - the number of bytes we want
5257  * @flush - whether or not we can flush to make our reservation
5258  *
5259  * This will reserve orig_bytes number of bytes from the space info associated
5260  * with the block_rsv.  If there is not enough space it will make an attempt to
5261  * flush out space to make room.  It will do this by flushing delalloc if
5262  * possible or committing the transaction.  If flush is 0 then no attempts to
5263  * regain reservations will be made and this will fail if there is not enough
5264  * space already.
5265  */
5266 static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
5267                                     struct btrfs_space_info *space_info,
5268                                     u64 orig_bytes,
5269                                     enum btrfs_reserve_flush_enum flush,
5270                                     bool system_chunk)
5271 {
5272         struct reserve_ticket ticket;
5273         u64 used;
5274         int ret = 0;
5275
5276         ASSERT(orig_bytes);
5277         ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5278
5279         spin_lock(&space_info->lock);
5280         ret = -ENOSPC;
5281         used = btrfs_space_info_used(space_info, true);
5282
5283         /*
5284          * If we have enough space then hooray, make our reservation and carry
5285          * on.  If not see if we can overcommit, and if we can, hooray carry on.
5286          * If not things get more complicated.
5287          */
5288         if (used + orig_bytes <= space_info->total_bytes) {
5289                 space_info->bytes_may_use += orig_bytes;
5290                 trace_btrfs_space_reservation(fs_info, "space_info",
5291                                               space_info->flags, orig_bytes, 1);
5292                 ret = 0;
5293         } else if (can_overcommit(fs_info, space_info, orig_bytes, flush,
5294                                   system_chunk)) {
5295                 space_info->bytes_may_use += orig_bytes;
5296                 trace_btrfs_space_reservation(fs_info, "space_info",
5297                                               space_info->flags, orig_bytes, 1);
5298                 ret = 0;
5299         }
5300
5301         /*
5302          * If we couldn't make a reservation then setup our reservation ticket
5303          * and kick the async worker if it's not already running.
5304          *
5305          * If we are a priority flusher then we just need to add our ticket to
5306          * the list and we will do our own flushing further down.
5307          */
5308         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5309                 ticket.bytes = orig_bytes;
5310                 ticket.error = 0;
5311                 init_waitqueue_head(&ticket.wait);
5312                 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5313                         list_add_tail(&ticket.list, &space_info->tickets);
5314                         if (!space_info->flush) {
5315                                 space_info->flush = 1;
5316                                 trace_btrfs_trigger_flush(fs_info,
5317                                                           space_info->flags,
5318                                                           orig_bytes, flush,
5319                                                           "enospc");
5320                                 queue_work(system_unbound_wq,
5321                                            &fs_info->async_reclaim_work);
5322                         }
5323                 } else {
5324                         list_add_tail(&ticket.list,
5325                                       &space_info->priority_tickets);
5326                 }
5327         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5328                 used += orig_bytes;
5329                 /*
5330                  * We will do the space reservation dance during log replay,
5331                  * which means we won't have fs_info->fs_root set, so don't do
5332                  * the async reclaim as we will panic.
5333                  */
5334                 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
5335                     need_do_async_reclaim(fs_info, space_info,
5336                                           used, system_chunk) &&
5337                     !work_busy(&fs_info->async_reclaim_work)) {
5338                         trace_btrfs_trigger_flush(fs_info, space_info->flags,
5339                                                   orig_bytes, flush, "preempt");
5340                         queue_work(system_unbound_wq,
5341                                    &fs_info->async_reclaim_work);
5342                 }
5343         }
5344         spin_unlock(&space_info->lock);
5345         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5346                 return ret;
5347
5348         if (flush == BTRFS_RESERVE_FLUSH_ALL)
5349                 return wait_reserve_ticket(fs_info, space_info, &ticket,
5350                                            orig_bytes);
5351
5352         ret = 0;
5353         priority_reclaim_metadata_space(fs_info, space_info, &ticket);
5354         spin_lock(&space_info->lock);
5355         if (ticket.bytes) {
5356                 if (ticket.bytes < orig_bytes) {
5357                         u64 num_bytes = orig_bytes - ticket.bytes;
5358                         space_info->bytes_may_use -= num_bytes;
5359                         trace_btrfs_space_reservation(fs_info, "space_info",
5360                                                       space_info->flags,
5361                                                       num_bytes, 0);
5362
5363                 }
5364                 list_del_init(&ticket.list);
5365                 ret = -ENOSPC;
5366         }
5367         spin_unlock(&space_info->lock);
5368         ASSERT(list_empty(&ticket.list));
5369         return ret;
5370 }
5371
5372 /**
5373  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5374  * @root - the root we're allocating for
5375  * @block_rsv - the block_rsv we're allocating for
5376  * @orig_bytes - the number of bytes we want
5377  * @flush - whether or not we can flush to make our reservation
5378  *
5379  * This will reserve orgi_bytes number of bytes from the space info associated
5380  * with the block_rsv.  If there is not enough space it will make an attempt to
5381  * flush out space to make room.  It will do this by flushing delalloc if
5382  * possible or committing the transaction.  If flush is 0 then no attempts to
5383  * regain reservations will be made and this will fail if there is not enough
5384  * space already.
5385  */
5386 static int reserve_metadata_bytes(struct btrfs_root *root,
5387                                   struct btrfs_block_rsv *block_rsv,
5388                                   u64 orig_bytes,
5389                                   enum btrfs_reserve_flush_enum flush)
5390 {
5391         struct btrfs_fs_info *fs_info = root->fs_info;
5392         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5393         int ret;
5394         bool system_chunk = (root == fs_info->chunk_root);
5395
5396         ret = __reserve_metadata_bytes(fs_info, block_rsv->space_info,
5397                                        orig_bytes, flush, system_chunk);
5398         if (ret == -ENOSPC &&
5399             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5400                 if (block_rsv != global_rsv &&
5401                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5402                         ret = 0;
5403         }
5404         if (ret == -ENOSPC)
5405                 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
5406                                               block_rsv->space_info->flags,
5407                                               orig_bytes, 1);
5408         return ret;
5409 }
5410
5411 static struct btrfs_block_rsv *get_block_rsv(
5412                                         const struct btrfs_trans_handle *trans,
5413                                         const struct btrfs_root *root)
5414 {
5415         struct btrfs_fs_info *fs_info = root->fs_info;
5416         struct btrfs_block_rsv *block_rsv = NULL;
5417
5418         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5419             (root == fs_info->csum_root && trans->adding_csums) ||
5420             (root == fs_info->uuid_root))
5421                 block_rsv = trans->block_rsv;
5422
5423         if (!block_rsv)
5424                 block_rsv = root->block_rsv;
5425
5426         if (!block_rsv)
5427                 block_rsv = &fs_info->empty_block_rsv;
5428
5429         return block_rsv;
5430 }
5431
5432 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5433                                u64 num_bytes)
5434 {
5435         int ret = -ENOSPC;
5436         spin_lock(&block_rsv->lock);
5437         if (block_rsv->reserved >= num_bytes) {
5438                 block_rsv->reserved -= num_bytes;
5439                 if (block_rsv->reserved < block_rsv->size)
5440                         block_rsv->full = 0;
5441                 ret = 0;
5442         }
5443         spin_unlock(&block_rsv->lock);
5444         return ret;
5445 }
5446
5447 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5448                                 u64 num_bytes, int update_size)
5449 {
5450         spin_lock(&block_rsv->lock);
5451         block_rsv->reserved += num_bytes;
5452         if (update_size)
5453                 block_rsv->size += num_bytes;
5454         else if (block_rsv->reserved >= block_rsv->size)
5455                 block_rsv->full = 1;
5456         spin_unlock(&block_rsv->lock);
5457 }
5458
5459 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5460                              struct btrfs_block_rsv *dest, u64 num_bytes,
5461                              int min_factor)
5462 {
5463         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5464         u64 min_bytes;
5465
5466         if (global_rsv->space_info != dest->space_info)
5467                 return -ENOSPC;
5468
5469         spin_lock(&global_rsv->lock);
5470         min_bytes = div_factor(global_rsv->size, min_factor);
5471         if (global_rsv->reserved < min_bytes + num_bytes) {
5472                 spin_unlock(&global_rsv->lock);
5473                 return -ENOSPC;
5474         }
5475         global_rsv->reserved -= num_bytes;
5476         if (global_rsv->reserved < global_rsv->size)
5477                 global_rsv->full = 0;
5478         spin_unlock(&global_rsv->lock);
5479
5480         block_rsv_add_bytes(dest, num_bytes, 1);
5481         return 0;
5482 }
5483
5484 /*
5485  * This is for space we already have accounted in space_info->bytes_may_use, so
5486  * basically when we're returning space from block_rsv's.
5487  */
5488 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5489                                      struct btrfs_space_info *space_info,
5490                                      u64 num_bytes)
5491 {
5492         struct reserve_ticket *ticket;
5493         struct list_head *head;
5494         u64 used;
5495         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5496         bool check_overcommit = false;
5497
5498         spin_lock(&space_info->lock);
5499         head = &space_info->priority_tickets;
5500
5501         /*
5502          * If we are over our limit then we need to check and see if we can
5503          * overcommit, and if we can't then we just need to free up our space
5504          * and not satisfy any requests.
5505          */
5506         used = btrfs_space_info_used(space_info, true);
5507         if (used - num_bytes >= space_info->total_bytes)
5508                 check_overcommit = true;
5509 again:
5510         while (!list_empty(head) && num_bytes) {
5511                 ticket = list_first_entry(head, struct reserve_ticket,
5512                                           list);
5513                 /*
5514                  * We use 0 bytes because this space is already reserved, so
5515                  * adding the ticket space would be a double count.
5516                  */
5517                 if (check_overcommit &&
5518                     !can_overcommit(fs_info, space_info, 0, flush, false))
5519                         break;
5520                 if (num_bytes >= ticket->bytes) {
5521                         list_del_init(&ticket->list);
5522                         num_bytes -= ticket->bytes;
5523                         ticket->bytes = 0;
5524                         space_info->tickets_id++;
5525                         wake_up(&ticket->wait);
5526                 } else {
5527                         ticket->bytes -= num_bytes;
5528                         num_bytes = 0;
5529                 }
5530         }
5531
5532         if (num_bytes && head == &space_info->priority_tickets) {
5533                 head = &space_info->tickets;
5534                 flush = BTRFS_RESERVE_FLUSH_ALL;
5535                 goto again;
5536         }
5537         space_info->bytes_may_use -= num_bytes;
5538         trace_btrfs_space_reservation(fs_info, "space_info",
5539                                       space_info->flags, num_bytes, 0);
5540         spin_unlock(&space_info->lock);
5541 }
5542
5543 /*
5544  * This is for newly allocated space that isn't accounted in
5545  * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
5546  * we use this helper.
5547  */
5548 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5549                                      struct btrfs_space_info *space_info,
5550                                      u64 num_bytes)
5551 {
5552         struct reserve_ticket *ticket;
5553         struct list_head *head = &space_info->priority_tickets;
5554
5555 again:
5556         while (!list_empty(head) && num_bytes) {
5557                 ticket = list_first_entry(head, struct reserve_ticket,
5558                                           list);
5559                 if (num_bytes >= ticket->bytes) {
5560                         trace_btrfs_space_reservation(fs_info, "space_info",
5561                                                       space_info->flags,
5562                                                       ticket->bytes, 1);
5563                         list_del_init(&ticket->list);
5564                         num_bytes -= ticket->bytes;
5565                         space_info->bytes_may_use += ticket->bytes;
5566                         ticket->bytes = 0;
5567                         space_info->tickets_id++;
5568                         wake_up(&ticket->wait);
5569                 } else {
5570                         trace_btrfs_space_reservation(fs_info, "space_info",
5571                                                       space_info->flags,
5572                                                       num_bytes, 1);
5573                         space_info->bytes_may_use += num_bytes;
5574                         ticket->bytes -= num_bytes;
5575                         num_bytes = 0;
5576                 }
5577         }
5578
5579         if (num_bytes && head == &space_info->priority_tickets) {
5580                 head = &space_info->tickets;
5581                 goto again;
5582         }
5583 }
5584
5585 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5586                                     struct btrfs_block_rsv *block_rsv,
5587                                     struct btrfs_block_rsv *dest, u64 num_bytes)
5588 {
5589         struct btrfs_space_info *space_info = block_rsv->space_info;
5590
5591         spin_lock(&block_rsv->lock);
5592         if (num_bytes == (u64)-1)
5593                 num_bytes = block_rsv->size;
5594         block_rsv->size -= num_bytes;
5595         if (block_rsv->reserved >= block_rsv->size) {
5596                 num_bytes = block_rsv->reserved - block_rsv->size;
5597                 block_rsv->reserved = block_rsv->size;
5598                 block_rsv->full = 1;
5599         } else {
5600                 num_bytes = 0;
5601         }
5602         spin_unlock(&block_rsv->lock);
5603
5604         if (num_bytes > 0) {
5605                 if (dest) {
5606                         spin_lock(&dest->lock);
5607                         if (!dest->full) {
5608                                 u64 bytes_to_add;
5609
5610                                 bytes_to_add = dest->size - dest->reserved;
5611                                 bytes_to_add = min(num_bytes, bytes_to_add);
5612                                 dest->reserved += bytes_to_add;
5613                                 if (dest->reserved >= dest->size)
5614                                         dest->full = 1;
5615                                 num_bytes -= bytes_to_add;
5616                         }
5617                         spin_unlock(&dest->lock);
5618                 }
5619                 if (num_bytes)
5620                         space_info_add_old_bytes(fs_info, space_info,
5621                                                  num_bytes);
5622         }
5623 }
5624
5625 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5626                             struct btrfs_block_rsv *dst, u64 num_bytes,
5627                             int update_size)
5628 {
5629         int ret;
5630
5631         ret = block_rsv_use_bytes(src, num_bytes);
5632         if (ret)
5633                 return ret;
5634
5635         block_rsv_add_bytes(dst, num_bytes, update_size);
5636         return 0;
5637 }
5638
5639 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5640 {
5641         memset(rsv, 0, sizeof(*rsv));
5642         spin_lock_init(&rsv->lock);
5643         rsv->type = type;
5644 }
5645
5646 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
5647                                               unsigned short type)
5648 {
5649         struct btrfs_block_rsv *block_rsv;
5650
5651         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5652         if (!block_rsv)
5653                 return NULL;
5654
5655         btrfs_init_block_rsv(block_rsv, type);
5656         block_rsv->space_info = __find_space_info(fs_info,
5657                                                   BTRFS_BLOCK_GROUP_METADATA);
5658         return block_rsv;
5659 }
5660
5661 void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
5662                           struct btrfs_block_rsv *rsv)
5663 {
5664         if (!rsv)
5665                 return;
5666         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5667         kfree(rsv);
5668 }
5669
5670 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5671 {
5672         kfree(rsv);
5673 }
5674
5675 int btrfs_block_rsv_add(struct btrfs_root *root,
5676                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5677                         enum btrfs_reserve_flush_enum flush)
5678 {
5679         int ret;
5680
5681         if (num_bytes == 0)
5682                 return 0;
5683
5684         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5685         if (!ret) {
5686                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5687                 return 0;
5688         }
5689
5690         return ret;
5691 }
5692
5693 int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
5694 {
5695         u64 num_bytes = 0;
5696         int ret = -ENOSPC;
5697
5698         if (!block_rsv)
5699                 return 0;
5700
5701         spin_lock(&block_rsv->lock);
5702         num_bytes = div_factor(block_rsv->size, min_factor);
5703         if (block_rsv->reserved >= num_bytes)
5704                 ret = 0;
5705         spin_unlock(&block_rsv->lock);
5706
5707         return ret;
5708 }
5709
5710 int btrfs_block_rsv_refill(struct btrfs_root *root,
5711                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5712                            enum btrfs_reserve_flush_enum flush)
5713 {
5714         u64 num_bytes = 0;
5715         int ret = -ENOSPC;
5716
5717         if (!block_rsv)
5718                 return 0;
5719
5720         spin_lock(&block_rsv->lock);
5721         num_bytes = min_reserved;
5722         if (block_rsv->reserved >= num_bytes)
5723                 ret = 0;
5724         else
5725                 num_bytes -= block_rsv->reserved;
5726         spin_unlock(&block_rsv->lock);
5727
5728         if (!ret)
5729                 return 0;
5730
5731         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5732         if (!ret) {
5733                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5734                 return 0;
5735         }
5736
5737         return ret;
5738 }
5739
5740 void btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
5741                              struct btrfs_block_rsv *block_rsv,
5742                              u64 num_bytes)
5743 {
5744         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5745
5746         if (global_rsv == block_rsv ||
5747             block_rsv->space_info != global_rsv->space_info)
5748                 global_rsv = NULL;
5749         block_rsv_release_bytes(fs_info, block_rsv, global_rsv, num_bytes);
5750 }
5751
5752 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5753 {
5754         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5755         struct btrfs_space_info *sinfo = block_rsv->space_info;
5756         u64 num_bytes;
5757
5758         /*
5759          * The global block rsv is based on the size of the extent tree, the
5760          * checksum tree and the root tree.  If the fs is empty we want to set
5761          * it to a minimal amount for safety.
5762          */
5763         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5764                 btrfs_root_used(&fs_info->csum_root->root_item) +
5765                 btrfs_root_used(&fs_info->tree_root->root_item);
5766         num_bytes = max_t(u64, num_bytes, SZ_16M);
5767
5768         spin_lock(&sinfo->lock);
5769         spin_lock(&block_rsv->lock);
5770
5771         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5772
5773         if (block_rsv->reserved < block_rsv->size) {
5774                 num_bytes = btrfs_space_info_used(sinfo, true);
5775                 if (sinfo->total_bytes > num_bytes) {
5776                         num_bytes = sinfo->total_bytes - num_bytes;
5777                         num_bytes = min(num_bytes,
5778                                         block_rsv->size - block_rsv->reserved);
5779                         block_rsv->reserved += num_bytes;
5780                         sinfo->bytes_may_use += num_bytes;
5781                         trace_btrfs_space_reservation(fs_info, "space_info",
5782                                                       sinfo->flags, num_bytes,
5783                                                       1);
5784                 }
5785         } else if (block_rsv->reserved > block_rsv->size) {
5786                 num_bytes = block_rsv->reserved - block_rsv->size;
5787                 sinfo->bytes_may_use -= num_bytes;
5788                 trace_btrfs_space_reservation(fs_info, "space_info",
5789                                       sinfo->flags, num_bytes, 0);
5790                 block_rsv->reserved = block_rsv->size;
5791         }
5792
5793         if (block_rsv->reserved == block_rsv->size)
5794                 block_rsv->full = 1;
5795         else
5796                 block_rsv->full = 0;
5797
5798         spin_unlock(&block_rsv->lock);
5799         spin_unlock(&sinfo->lock);
5800 }
5801
5802 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5803 {
5804         struct btrfs_space_info *space_info;
5805
5806         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5807         fs_info->chunk_block_rsv.space_info = space_info;
5808
5809         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5810         fs_info->global_block_rsv.space_info = space_info;
5811         fs_info->delalloc_block_rsv.space_info = space_info;
5812         fs_info->trans_block_rsv.space_info = space_info;
5813         fs_info->empty_block_rsv.space_info = space_info;
5814         fs_info->delayed_block_rsv.space_info = space_info;
5815
5816         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5817         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5818         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5819         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5820         if (fs_info->quota_root)
5821                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5822         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5823
5824         update_global_block_rsv(fs_info);
5825 }
5826
5827 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5828 {
5829         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5830                                 (u64)-1);
5831         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5832         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5833         WARN_ON(fs_info->trans_block_rsv.size > 0);
5834         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5835         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5836         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5837         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5838         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5839 }
5840
5841 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5842                                   struct btrfs_fs_info *fs_info)
5843 {
5844         if (!trans->block_rsv)
5845                 return;
5846
5847         if (!trans->bytes_reserved)
5848                 return;
5849
5850         trace_btrfs_space_reservation(fs_info, "transaction",
5851                                       trans->transid, trans->bytes_reserved, 0);
5852         btrfs_block_rsv_release(fs_info, trans->block_rsv,
5853                                 trans->bytes_reserved);
5854         trans->bytes_reserved = 0;
5855 }
5856
5857 /*
5858  * To be called after all the new block groups attached to the transaction
5859  * handle have been created (btrfs_create_pending_block_groups()).
5860  */
5861 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5862 {
5863         struct btrfs_fs_info *fs_info = trans->fs_info;
5864
5865         if (!trans->chunk_bytes_reserved)
5866                 return;
5867
5868         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5869
5870         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5871                                 trans->chunk_bytes_reserved);
5872         trans->chunk_bytes_reserved = 0;
5873 }
5874
5875 /* Can only return 0 or -ENOSPC */
5876 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5877                                   struct btrfs_inode *inode)
5878 {
5879         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
5880         struct btrfs_root *root = inode->root;
5881         /*
5882          * We always use trans->block_rsv here as we will have reserved space
5883          * for our orphan when starting the transaction, using get_block_rsv()
5884          * here will sometimes make us choose the wrong block rsv as we could be
5885          * doing a reloc inode for a non refcounted root.
5886          */
5887         struct btrfs_block_rsv *src_rsv = trans->block_rsv;
5888         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5889
5890         /*
5891          * We need to hold space in order to delete our orphan item once we've
5892          * added it, so this takes the reservation so we can release it later
5893          * when we are truly done with the orphan item.
5894          */
5895         u64 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
5896
5897         trace_btrfs_space_reservation(fs_info, "orphan", btrfs_ino(inode),
5898                         num_bytes, 1);
5899         return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
5900 }
5901
5902 void btrfs_orphan_release_metadata(struct btrfs_inode *inode)
5903 {
5904         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
5905         struct btrfs_root *root = inode->root;
5906         u64 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
5907
5908         trace_btrfs_space_reservation(fs_info, "orphan", btrfs_ino(inode),
5909                         num_bytes, 0);
5910         btrfs_block_rsv_release(fs_info, root->orphan_block_rsv, num_bytes);
5911 }
5912
5913 /*
5914  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5915  * root: the root of the parent directory
5916  * rsv: block reservation
5917  * items: the number of items that we need do reservation
5918  * qgroup_reserved: used to return the reserved size in qgroup
5919  *
5920  * This function is used to reserve the space for snapshot/subvolume
5921  * creation and deletion. Those operations are different with the
5922  * common file/directory operations, they change two fs/file trees
5923  * and root tree, the number of items that the qgroup reserves is
5924  * different with the free space reservation. So we can not use
5925  * the space reservation mechanism in start_transaction().
5926  */
5927 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5928                                      struct btrfs_block_rsv *rsv,
5929                                      int items,
5930                                      u64 *qgroup_reserved,
5931                                      bool use_global_rsv)
5932 {
5933         u64 num_bytes;
5934         int ret;
5935         struct btrfs_fs_info *fs_info = root->fs_info;
5936         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5937
5938         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
5939                 /* One for parent inode, two for dir entries */
5940                 num_bytes = 3 * fs_info->nodesize;
5941                 ret = btrfs_qgroup_reserve_meta(root, num_bytes, true);
5942                 if (ret)
5943                         return ret;
5944         } else {
5945                 num_bytes = 0;
5946         }
5947
5948         *qgroup_reserved = num_bytes;
5949
5950         num_bytes = btrfs_calc_trans_metadata_size(fs_info, items);
5951         rsv->space_info = __find_space_info(fs_info,
5952                                             BTRFS_BLOCK_GROUP_METADATA);
5953         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5954                                   BTRFS_RESERVE_FLUSH_ALL);
5955
5956         if (ret == -ENOSPC && use_global_rsv)
5957                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5958
5959         if (ret && *qgroup_reserved)
5960                 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5961
5962         return ret;
5963 }
5964
5965 void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
5966                                       struct btrfs_block_rsv *rsv)
5967 {
5968         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5969 }
5970
5971 /**
5972  * drop_outstanding_extent - drop an outstanding extent
5973  * @inode: the inode we're dropping the extent for
5974  * @num_bytes: the number of bytes we're releasing.
5975  *
5976  * This is called when we are freeing up an outstanding extent, either called
5977  * after an error or after an extent is written.  This will return the number of
5978  * reserved extents that need to be freed.  This must be called with
5979  * BTRFS_I(inode)->lock held.
5980  */
5981 static unsigned drop_outstanding_extent(struct btrfs_inode *inode,
5982                 u64 num_bytes)
5983 {
5984         unsigned drop_inode_space = 0;
5985         unsigned dropped_extents = 0;
5986         unsigned num_extents;
5987
5988         num_extents = count_max_extents(num_bytes);
5989         ASSERT(num_extents);
5990         ASSERT(inode->outstanding_extents >= num_extents);
5991         inode->outstanding_extents -= num_extents;
5992
5993         if (inode->outstanding_extents == 0 &&
5994             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5995                                &inode->runtime_flags))
5996                 drop_inode_space = 1;
5997
5998         /*
5999          * If we have more or the same amount of outstanding extents than we have
6000          * reserved then we need to leave the reserved extents count alone.
6001          */
6002         if (inode->outstanding_extents >= inode->reserved_extents)
6003                 return drop_inode_space;
6004
6005         dropped_extents = inode->reserved_extents - inode->outstanding_extents;
6006         inode->reserved_extents -= dropped_extents;
6007         return dropped_extents + drop_inode_space;
6008 }
6009
6010 /**
6011  * calc_csum_metadata_size - return the amount of metadata space that must be
6012  *      reserved/freed for the given bytes.
6013  * @inode: the inode we're manipulating
6014  * @num_bytes: the number of bytes in question
6015  * @reserve: 1 if we are reserving space, 0 if we are freeing space
6016  *
6017  * This adjusts the number of csum_bytes in the inode and then returns the
6018  * correct amount of metadata that must either be reserved or freed.  We
6019  * calculate how many checksums we can fit into one leaf and then divide the
6020  * number of bytes that will need to be checksumed by this value to figure out
6021  * how many checksums will be required.  If we are adding bytes then the number
6022  * may go up and we will return the number of additional bytes that must be
6023  * reserved.  If it is going down we will return the number of bytes that must
6024  * be freed.
6025  *
6026  * This must be called with BTRFS_I(inode)->lock held.
6027  */
6028 static u64 calc_csum_metadata_size(struct btrfs_inode *inode, u64 num_bytes,
6029                                    int reserve)
6030 {
6031         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6032         u64 old_csums, num_csums;
6033
6034         if (inode->flags & BTRFS_INODE_NODATASUM && inode->csum_bytes == 0)
6035                 return 0;
6036
6037         old_csums = btrfs_csum_bytes_to_leaves(fs_info, inode->csum_bytes);
6038         if (reserve)
6039                 inode->csum_bytes += num_bytes;
6040         else
6041                 inode->csum_bytes -= num_bytes;
6042         num_csums = btrfs_csum_bytes_to_leaves(fs_info, inode->csum_bytes);
6043
6044         /* No change, no need to reserve more */
6045         if (old_csums == num_csums)
6046                 return 0;
6047
6048         if (reserve)
6049                 return btrfs_calc_trans_metadata_size(fs_info,
6050                                                       num_csums - old_csums);
6051
6052         return btrfs_calc_trans_metadata_size(fs_info, old_csums - num_csums);
6053 }
6054
6055 int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
6056 {
6057         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6058         struct btrfs_root *root = inode->root;
6059         struct btrfs_block_rsv *block_rsv = &fs_info->delalloc_block_rsv;
6060         u64 to_reserve = 0;
6061         u64 csum_bytes;
6062         unsigned nr_extents;
6063         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
6064         int ret = 0;
6065         bool delalloc_lock = true;
6066         u64 to_free = 0;
6067         unsigned dropped;
6068         bool release_extra = false;
6069
6070         /* If we are a free space inode we need to not flush since we will be in
6071          * the middle of a transaction commit.  We also don't need the delalloc
6072          * mutex since we won't race with anybody.  We need this mostly to make
6073          * lockdep shut its filthy mouth.
6074          *
6075          * If we have a transaction open (can happen if we call truncate_block
6076          * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
6077          */
6078         if (btrfs_is_free_space_inode(inode)) {
6079                 flush = BTRFS_RESERVE_NO_FLUSH;
6080                 delalloc_lock = false;
6081         } else if (current->journal_info) {
6082                 flush = BTRFS_RESERVE_FLUSH_LIMIT;
6083         }
6084
6085         if (flush != BTRFS_RESERVE_NO_FLUSH &&
6086             btrfs_transaction_in_commit(fs_info))
6087                 schedule_timeout(1);
6088
6089         if (delalloc_lock)
6090                 mutex_lock(&inode->delalloc_mutex);
6091
6092         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
6093
6094         spin_lock(&inode->lock);
6095         nr_extents = count_max_extents(num_bytes);
6096         inode->outstanding_extents += nr_extents;
6097
6098         nr_extents = 0;
6099         if (inode->outstanding_extents > inode->reserved_extents)
6100                 nr_extents += inode->outstanding_extents -
6101                         inode->reserved_extents;
6102
6103         /* We always want to reserve a slot for updating the inode. */
6104         to_reserve = btrfs_calc_trans_metadata_size(fs_info, nr_extents + 1);
6105         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
6106         csum_bytes = inode->csum_bytes;
6107         spin_unlock(&inode->lock);
6108
6109         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
6110                 ret = btrfs_qgroup_reserve_meta(root,
6111                                 nr_extents * fs_info->nodesize, true);
6112                 if (ret)
6113                         goto out_fail;
6114         }
6115
6116         ret = btrfs_block_rsv_add(root, block_rsv, to_reserve, flush);
6117         if (unlikely(ret)) {
6118                 btrfs_qgroup_free_meta(root,
6119                                        nr_extents * fs_info->nodesize);
6120                 goto out_fail;
6121         }
6122
6123         spin_lock(&inode->lock);
6124         if (test_and_set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
6125                              &inode->runtime_flags)) {
6126                 to_reserve -= btrfs_calc_trans_metadata_size(fs_info, 1);
6127                 release_extra = true;
6128         }
6129         inode->reserved_extents += nr_extents;
6130         spin_unlock(&inode->lock);
6131
6132         if (delalloc_lock)
6133                 mutex_unlock(&inode->delalloc_mutex);
6134
6135         if (to_reserve)
6136                 trace_btrfs_space_reservation(fs_info, "delalloc",
6137                                               btrfs_ino(inode), to_reserve, 1);
6138         if (release_extra)
6139                 btrfs_block_rsv_release(fs_info, block_rsv,
6140                                 btrfs_calc_trans_metadata_size(fs_info, 1));
6141         return 0;
6142
6143 out_fail:
6144         spin_lock(&inode->lock);
6145         dropped = drop_outstanding_extent(inode, num_bytes);
6146         /*
6147          * If the inodes csum_bytes is the same as the original
6148          * csum_bytes then we know we haven't raced with any free()ers
6149          * so we can just reduce our inodes csum bytes and carry on.
6150          */
6151         if (inode->csum_bytes == csum_bytes) {
6152                 calc_csum_metadata_size(inode, num_bytes, 0);
6153         } else {
6154                 u64 orig_csum_bytes = inode->csum_bytes;
6155                 u64 bytes;
6156
6157                 /*
6158                  * This is tricky, but first we need to figure out how much we
6159                  * freed from any free-ers that occurred during this
6160                  * reservation, so we reset ->csum_bytes to the csum_bytes
6161                  * before we dropped our lock, and then call the free for the
6162                  * number of bytes that were freed while we were trying our
6163                  * reservation.
6164                  */
6165                 bytes = csum_bytes - inode->csum_bytes;
6166                 inode->csum_bytes = csum_bytes;
6167                 to_free = calc_csum_metadata_size(inode, bytes, 0);
6168
6169
6170                 /*
6171                  * Now we need to see how much we would have freed had we not
6172                  * been making this reservation and our ->csum_bytes were not
6173                  * artificially inflated.
6174                  */
6175                 inode->csum_bytes = csum_bytes - num_bytes;
6176                 bytes = csum_bytes - orig_csum_bytes;
6177                 bytes = calc_csum_metadata_size(inode, bytes, 0);
6178
6179                 /*
6180                  * Now reset ->csum_bytes to what it should be.  If bytes is
6181                  * more than to_free then we would have freed more space had we
6182                  * not had an artificially high ->csum_bytes, so we need to free
6183                  * the remainder.  If bytes is the same or less then we don't
6184                  * need to do anything, the other free-ers did the correct
6185                  * thing.
6186                  */
6187                 inode->csum_bytes = orig_csum_bytes - num_bytes;
6188                 if (bytes > to_free)
6189                         to_free = bytes - to_free;
6190                 else
6191                         to_free = 0;
6192         }
6193         spin_unlock(&inode->lock);
6194         if (dropped)
6195                 to_free += btrfs_calc_trans_metadata_size(fs_info, dropped);
6196
6197         if (to_free) {
6198                 btrfs_block_rsv_release(fs_info, block_rsv, to_free);
6199                 trace_btrfs_space_reservation(fs_info, "delalloc",
6200                                               btrfs_ino(inode), to_free, 0);
6201         }
6202         if (delalloc_lock)
6203                 mutex_unlock(&inode->delalloc_mutex);
6204         return ret;
6205 }
6206
6207 /**
6208  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6209  * @inode: the inode to release the reservation for
6210  * @num_bytes: the number of bytes we're releasing
6211  *
6212  * This will release the metadata reservation for an inode.  This can be called
6213  * once we complete IO for a given set of bytes to release their metadata
6214  * reservations.
6215  */
6216 void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes)
6217 {
6218         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6219         u64 to_free = 0;
6220         unsigned dropped;
6221
6222         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
6223         spin_lock(&inode->lock);
6224         dropped = drop_outstanding_extent(inode, num_bytes);
6225
6226         if (num_bytes)
6227                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
6228         spin_unlock(&inode->lock);
6229         if (dropped > 0)
6230                 to_free += btrfs_calc_trans_metadata_size(fs_info, dropped);
6231
6232         if (btrfs_is_testing(fs_info))
6233                 return;
6234
6235         trace_btrfs_space_reservation(fs_info, "delalloc", btrfs_ino(inode),
6236                                       to_free, 0);
6237
6238         btrfs_block_rsv_release(fs_info, &fs_info->delalloc_block_rsv, to_free);
6239 }
6240
6241 /**
6242  * btrfs_delalloc_reserve_space - reserve data and metadata space for
6243  * delalloc
6244  * @inode: inode we're writing to
6245  * @start: start range we are writing to
6246  * @len: how long the range we are writing to
6247  * @reserved: mandatory parameter, record actually reserved qgroup ranges of
6248  *            current reservation.
6249  *
6250  * This will do the following things
6251  *
6252  * o reserve space in data space info for num bytes
6253  *   and reserve precious corresponding qgroup space
6254  *   (Done in check_data_free_space)
6255  *
6256  * o reserve space for metadata space, based on the number of outstanding
6257  *   extents and how much csums will be needed
6258  *   also reserve metadata space in a per root over-reserve method.
6259  * o add to the inodes->delalloc_bytes
6260  * o add it to the fs_info's delalloc inodes list.
6261  *   (Above 3 all done in delalloc_reserve_metadata)
6262  *
6263  * Return 0 for success
6264  * Return <0 for error(-ENOSPC or -EQUOT)
6265  */
6266 int btrfs_delalloc_reserve_space(struct inode *inode,
6267                         struct extent_changeset **reserved, u64 start, u64 len)
6268 {
6269         int ret;
6270
6271         ret = btrfs_check_data_free_space(inode, reserved, start, len);
6272         if (ret < 0)
6273                 return ret;
6274         ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len);
6275         if (ret < 0)
6276                 btrfs_free_reserved_data_space(inode, *reserved, start, len);
6277         return ret;
6278 }
6279
6280 /**
6281  * btrfs_delalloc_release_space - release data and metadata space for delalloc
6282  * @inode: inode we're releasing space for
6283  * @start: start position of the space already reserved
6284  * @len: the len of the space already reserved
6285  *
6286  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
6287  * called in the case that we don't need the metadata AND data reservations
6288  * anymore.  So if there is an error or we insert an inline extent.
6289  *
6290  * This function will release the metadata space that was not used and will
6291  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6292  * list if there are no delalloc bytes left.
6293  * Also it will handle the qgroup reserved space.
6294  */
6295 void btrfs_delalloc_release_space(struct inode *inode,
6296                         struct extent_changeset *reserved, u64 start, u64 len)
6297 {
6298         btrfs_delalloc_release_metadata(BTRFS_I(inode), len);
6299         btrfs_free_reserved_data_space(inode, reserved, start, len);
6300 }
6301
6302 static int update_block_group(struct btrfs_trans_handle *trans,
6303                               struct btrfs_fs_info *info, u64 bytenr,
6304                               u64 num_bytes, int alloc)
6305 {
6306         struct btrfs_block_group_cache *cache = NULL;
6307         u64 total = num_bytes;
6308         u64 old_val;
6309         u64 byte_in_group;
6310         int factor;
6311
6312         /* block accounting for super block */
6313         spin_lock(&info->delalloc_root_lock);
6314         old_val = btrfs_super_bytes_used(info->super_copy);
6315         if (alloc)
6316                 old_val += num_bytes;
6317         else
6318                 old_val -= num_bytes;
6319         btrfs_set_super_bytes_used(info->super_copy, old_val);
6320         spin_unlock(&info->delalloc_root_lock);
6321
6322         while (total) {
6323                 cache = btrfs_lookup_block_group(info, bytenr);
6324                 if (!cache)
6325                         return -ENOENT;
6326                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6327                                     BTRFS_BLOCK_GROUP_RAID1 |
6328                                     BTRFS_BLOCK_GROUP_RAID10))
6329                         factor = 2;
6330                 else
6331                         factor = 1;
6332                 /*
6333                  * If this block group has free space cache written out, we
6334                  * need to make sure to load it if we are removing space.  This
6335                  * is because we need the unpinning stage to actually add the
6336                  * space back to the block group, otherwise we will leak space.
6337                  */
6338                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6339                         cache_block_group(cache, 1);
6340
6341                 byte_in_group = bytenr - cache->key.objectid;
6342                 WARN_ON(byte_in_group > cache->key.offset);
6343
6344                 spin_lock(&cache->space_info->lock);
6345                 spin_lock(&cache->lock);
6346
6347                 if (btrfs_test_opt(info, SPACE_CACHE) &&
6348                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6349                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6350
6351                 old_val = btrfs_block_group_used(&cache->item);
6352                 num_bytes = min(total, cache->key.offset - byte_in_group);
6353                 if (alloc) {
6354                         old_val += num_bytes;
6355                         btrfs_set_block_group_used(&cache->item, old_val);
6356                         cache->reserved -= num_bytes;
6357                         cache->space_info->bytes_reserved -= num_bytes;
6358                         cache->space_info->bytes_used += num_bytes;
6359                         cache->space_info->disk_used += num_bytes * factor;
6360                         spin_unlock(&cache->lock);
6361                         spin_unlock(&cache->space_info->lock);
6362                 } else {
6363                         old_val -= num_bytes;
6364                         btrfs_set_block_group_used(&cache->item, old_val);
6365                         cache->pinned += num_bytes;
6366                         cache->space_info->bytes_pinned += num_bytes;
6367                         cache->space_info->bytes_used -= num_bytes;
6368                         cache->space_info->disk_used -= num_bytes * factor;
6369                         spin_unlock(&cache->lock);
6370                         spin_unlock(&cache->space_info->lock);
6371
6372                         trace_btrfs_space_reservation(info, "pinned",
6373                                                       cache->space_info->flags,
6374                                                       num_bytes, 1);
6375                         percpu_counter_add(&cache->space_info->total_bytes_pinned,
6376                                            num_bytes);
6377                         set_extent_dirty(info->pinned_extents,
6378                                          bytenr, bytenr + num_bytes - 1,
6379                                          GFP_NOFS | __GFP_NOFAIL);
6380                 }
6381
6382                 spin_lock(&trans->transaction->dirty_bgs_lock);
6383                 if (list_empty(&cache->dirty_list)) {
6384                         list_add_tail(&cache->dirty_list,
6385                                       &trans->transaction->dirty_bgs);
6386                                 trans->transaction->num_dirty_bgs++;
6387                         btrfs_get_block_group(cache);
6388                 }
6389                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6390
6391                 /*
6392                  * No longer have used bytes in this block group, queue it for
6393                  * deletion. We do this after adding the block group to the
6394                  * dirty list to avoid races between cleaner kthread and space
6395                  * cache writeout.
6396                  */
6397                 if (!alloc && old_val == 0) {
6398                         spin_lock(&info->unused_bgs_lock);
6399                         if (list_empty(&cache->bg_list)) {
6400                                 btrfs_get_block_group(cache);
6401                                 list_add_tail(&cache->bg_list,
6402                                               &info->unused_bgs);
6403                         }
6404                         spin_unlock(&info->unused_bgs_lock);
6405                 }
6406
6407                 btrfs_put_block_group(cache);
6408                 total -= num_bytes;
6409                 bytenr += num_bytes;
6410         }
6411         return 0;
6412 }
6413
6414 static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
6415 {
6416         struct btrfs_block_group_cache *cache;
6417         u64 bytenr;
6418
6419         spin_lock(&fs_info->block_group_cache_lock);
6420         bytenr = fs_info->first_logical_byte;
6421         spin_unlock(&fs_info->block_group_cache_lock);
6422
6423         if (bytenr < (u64)-1)
6424                 return bytenr;
6425
6426         cache = btrfs_lookup_first_block_group(fs_info, search_start);
6427         if (!cache)
6428                 return 0;
6429
6430         bytenr = cache->key.objectid;
6431         btrfs_put_block_group(cache);
6432
6433         return bytenr;
6434 }
6435
6436 static int pin_down_extent(struct btrfs_fs_info *fs_info,
6437                            struct btrfs_block_group_cache *cache,
6438                            u64 bytenr, u64 num_bytes, int reserved)
6439 {
6440         spin_lock(&cache->space_info->lock);
6441         spin_lock(&cache->lock);
6442         cache->pinned += num_bytes;
6443         cache->space_info->bytes_pinned += num_bytes;
6444         if (reserved) {
6445                 cache->reserved -= num_bytes;
6446                 cache->space_info->bytes_reserved -= num_bytes;
6447         }
6448         spin_unlock(&cache->lock);
6449         spin_unlock(&cache->space_info->lock);
6450
6451         trace_btrfs_space_reservation(fs_info, "pinned",
6452                                       cache->space_info->flags, num_bytes, 1);
6453         percpu_counter_add(&cache->space_info->total_bytes_pinned, num_bytes);
6454         set_extent_dirty(fs_info->pinned_extents, bytenr,
6455                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6456         return 0;
6457 }
6458
6459 /*
6460  * this function must be called within transaction
6461  */
6462 int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
6463                      u64 bytenr, u64 num_bytes, int reserved)
6464 {
6465         struct btrfs_block_group_cache *cache;
6466
6467         cache = btrfs_lookup_block_group(fs_info, bytenr);
6468         BUG_ON(!cache); /* Logic error */
6469
6470         pin_down_extent(fs_info, cache, bytenr, num_bytes, reserved);
6471
6472         btrfs_put_block_group(cache);
6473         return 0;
6474 }
6475
6476 /*
6477  * this function must be called within transaction
6478  */
6479 int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
6480                                     u64 bytenr, u64 num_bytes)
6481 {
6482         struct btrfs_block_group_cache *cache;
6483         int ret;
6484
6485         cache = btrfs_lookup_block_group(fs_info, bytenr);
6486         if (!cache)
6487                 return -EINVAL;
6488
6489         /*
6490          * pull in the free space cache (if any) so that our pin
6491          * removes the free space from the cache.  We have load_only set
6492          * to one because the slow code to read in the free extents does check
6493          * the pinned extents.
6494          */
6495         cache_block_group(cache, 1);
6496
6497         pin_down_extent(fs_info, cache, bytenr, num_bytes, 0);
6498
6499         /* remove us from the free space cache (if we're there at all) */
6500         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6501         btrfs_put_block_group(cache);
6502         return ret;
6503 }
6504
6505 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
6506                                    u64 start, u64 num_bytes)
6507 {
6508         int ret;
6509         struct btrfs_block_group_cache *block_group;
6510         struct btrfs_caching_control *caching_ctl;
6511
6512         block_group = btrfs_lookup_block_group(fs_info, start);
6513         if (!block_group)
6514                 return -EINVAL;
6515
6516         cache_block_group(block_group, 0);
6517         caching_ctl = get_caching_control(block_group);
6518
6519         if (!caching_ctl) {
6520                 /* Logic error */
6521                 BUG_ON(!block_group_cache_done(block_group));
6522                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6523         } else {
6524                 mutex_lock(&caching_ctl->mutex);
6525
6526                 if (start >= caching_ctl->progress) {
6527                         ret = add_excluded_extent(fs_info, start, num_bytes);
6528                 } else if (start + num_bytes <= caching_ctl->progress) {
6529                         ret = btrfs_remove_free_space(block_group,
6530                                                       start, num_bytes);
6531                 } else {
6532                         num_bytes = caching_ctl->progress - start;
6533                         ret = btrfs_remove_free_space(block_group,
6534                                                       start, num_bytes);
6535                         if (ret)
6536                                 goto out_lock;
6537
6538                         num_bytes = (start + num_bytes) -
6539                                 caching_ctl->progress;
6540                         start = caching_ctl->progress;
6541                         ret = add_excluded_extent(fs_info, start, num_bytes);
6542                 }
6543 out_lock:
6544                 mutex_unlock(&caching_ctl->mutex);
6545                 put_caching_control(caching_ctl);
6546         }
6547         btrfs_put_block_group(block_group);
6548         return ret;
6549 }
6550
6551 int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
6552                                  struct extent_buffer *eb)
6553 {
6554         struct btrfs_file_extent_item *item;
6555         struct btrfs_key key;
6556         int found_type;
6557         int i;
6558
6559         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
6560                 return 0;
6561
6562         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6563                 btrfs_item_key_to_cpu(eb, &key, i);
6564                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6565                         continue;
6566                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6567                 found_type = btrfs_file_extent_type(eb, item);
6568                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6569                         continue;
6570                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6571                         continue;
6572                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6573                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6574                 __exclude_logged_extent(fs_info, key.objectid, key.offset);
6575         }
6576
6577         return 0;
6578 }
6579
6580 static void
6581 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6582 {
6583         atomic_inc(&bg->reservations);
6584 }
6585
6586 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6587                                         const u64 start)
6588 {
6589         struct btrfs_block_group_cache *bg;
6590
6591         bg = btrfs_lookup_block_group(fs_info, start);
6592         ASSERT(bg);
6593         if (atomic_dec_and_test(&bg->reservations))
6594                 wake_up_atomic_t(&bg->reservations);
6595         btrfs_put_block_group(bg);
6596 }
6597
6598 static int btrfs_wait_bg_reservations_atomic_t(atomic_t *a)
6599 {
6600         schedule();
6601         return 0;
6602 }
6603
6604 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6605 {
6606         struct btrfs_space_info *space_info = bg->space_info;
6607
6608         ASSERT(bg->ro);
6609
6610         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6611                 return;
6612
6613         /*
6614          * Our block group is read only but before we set it to read only,
6615          * some task might have had allocated an extent from it already, but it
6616          * has not yet created a respective ordered extent (and added it to a
6617          * root's list of ordered extents).
6618          * Therefore wait for any task currently allocating extents, since the
6619          * block group's reservations counter is incremented while a read lock
6620          * on the groups' semaphore is held and decremented after releasing
6621          * the read access on that semaphore and creating the ordered extent.
6622          */
6623         down_write(&space_info->groups_sem);
6624         up_write(&space_info->groups_sem);
6625
6626         wait_on_atomic_t(&bg->reservations,
6627                          btrfs_wait_bg_reservations_atomic_t,
6628                          TASK_UNINTERRUPTIBLE);
6629 }
6630
6631 /**
6632  * btrfs_add_reserved_bytes - update the block_group and space info counters
6633  * @cache:      The cache we are manipulating
6634  * @ram_bytes:  The number of bytes of file content, and will be same to
6635  *              @num_bytes except for the compress path.
6636  * @num_bytes:  The number of bytes in question
6637  * @delalloc:   The blocks are allocated for the delalloc write
6638  *
6639  * This is called by the allocator when it reserves space. If this is a
6640  * reservation and the block group has become read only we cannot make the
6641  * reservation and return -EAGAIN, otherwise this function always succeeds.
6642  */
6643 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6644                                     u64 ram_bytes, u64 num_bytes, int delalloc)
6645 {
6646         struct btrfs_space_info *space_info = cache->space_info;
6647         int ret = 0;
6648
6649         spin_lock(&space_info->lock);
6650         spin_lock(&cache->lock);
6651         if (cache->ro) {
6652                 ret = -EAGAIN;
6653         } else {
6654                 cache->reserved += num_bytes;
6655                 space_info->bytes_reserved += num_bytes;
6656
6657                 trace_btrfs_space_reservation(cache->fs_info,
6658                                 "space_info", space_info->flags,
6659                                 ram_bytes, 0);
6660                 space_info->bytes_may_use -= ram_bytes;
6661                 if (delalloc)
6662                         cache->delalloc_bytes += num_bytes;
6663         }
6664         spin_unlock(&cache->lock);
6665         spin_unlock(&space_info->lock);
6666         return ret;
6667 }
6668
6669 /**
6670  * btrfs_free_reserved_bytes - update the block_group and space info counters
6671  * @cache:      The cache we are manipulating
6672  * @num_bytes:  The number of bytes in question
6673  * @delalloc:   The blocks are allocated for the delalloc write
6674  *
6675  * This is called by somebody who is freeing space that was never actually used
6676  * on disk.  For example if you reserve some space for a new leaf in transaction
6677  * A and before transaction A commits you free that leaf, you call this with
6678  * reserve set to 0 in order to clear the reservation.
6679  */
6680
6681 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6682                                      u64 num_bytes, int delalloc)
6683 {
6684         struct btrfs_space_info *space_info = cache->space_info;
6685         int ret = 0;
6686
6687         spin_lock(&space_info->lock);
6688         spin_lock(&cache->lock);
6689         if (cache->ro)
6690                 space_info->bytes_readonly += num_bytes;
6691         cache->reserved -= num_bytes;
6692         space_info->bytes_reserved -= num_bytes;
6693
6694         if (delalloc)
6695                 cache->delalloc_bytes -= num_bytes;
6696         spin_unlock(&cache->lock);
6697         spin_unlock(&space_info->lock);
6698         return ret;
6699 }
6700 void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
6701 {
6702         struct btrfs_caching_control *next;
6703         struct btrfs_caching_control *caching_ctl;
6704         struct btrfs_block_group_cache *cache;
6705
6706         down_write(&fs_info->commit_root_sem);
6707
6708         list_for_each_entry_safe(caching_ctl, next,
6709                                  &fs_info->caching_block_groups, list) {
6710                 cache = caching_ctl->block_group;
6711                 if (block_group_cache_done(cache)) {
6712                         cache->last_byte_to_unpin = (u64)-1;
6713                         list_del_init(&caching_ctl->list);
6714                         put_caching_control(caching_ctl);
6715                 } else {
6716                         cache->last_byte_to_unpin = caching_ctl->progress;
6717                 }
6718         }
6719
6720         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6721                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6722         else
6723                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6724
6725         up_write(&fs_info->commit_root_sem);
6726
6727         update_global_block_rsv(fs_info);
6728 }
6729
6730 /*
6731  * Returns the free cluster for the given space info and sets empty_cluster to
6732  * what it should be based on the mount options.
6733  */
6734 static struct btrfs_free_cluster *
6735 fetch_cluster_info(struct btrfs_fs_info *fs_info,
6736                    struct btrfs_space_info *space_info, u64 *empty_cluster)
6737 {
6738         struct btrfs_free_cluster *ret = NULL;
6739
6740         *empty_cluster = 0;
6741         if (btrfs_mixed_space_info(space_info))
6742                 return ret;
6743
6744         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6745                 ret = &fs_info->meta_alloc_cluster;
6746                 if (btrfs_test_opt(fs_info, SSD))
6747                         *empty_cluster = SZ_2M;
6748                 else
6749                         *empty_cluster = SZ_64K;
6750         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
6751                    btrfs_test_opt(fs_info, SSD_SPREAD)) {
6752                 *empty_cluster = SZ_2M;
6753                 ret = &fs_info->data_alloc_cluster;
6754         }
6755
6756         return ret;
6757 }
6758
6759 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
6760                               u64 start, u64 end,
6761                               const bool return_free_space)
6762 {
6763         struct btrfs_block_group_cache *cache = NULL;
6764         struct btrfs_space_info *space_info;
6765         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6766         struct btrfs_free_cluster *cluster = NULL;
6767         u64 len;
6768         u64 total_unpinned = 0;
6769         u64 empty_cluster = 0;
6770         bool readonly;
6771
6772         while (start <= end) {
6773                 readonly = false;
6774                 if (!cache ||
6775                     start >= cache->key.objectid + cache->key.offset) {
6776                         if (cache)
6777                                 btrfs_put_block_group(cache);
6778                         total_unpinned = 0;
6779                         cache = btrfs_lookup_block_group(fs_info, start);
6780                         BUG_ON(!cache); /* Logic error */
6781
6782                         cluster = fetch_cluster_info(fs_info,
6783                                                      cache->space_info,
6784                                                      &empty_cluster);
6785                         empty_cluster <<= 1;
6786                 }
6787
6788                 len = cache->key.objectid + cache->key.offset - start;
6789                 len = min(len, end + 1 - start);
6790
6791                 if (start < cache->last_byte_to_unpin) {
6792                         len = min(len, cache->last_byte_to_unpin - start);
6793                         if (return_free_space)
6794                                 btrfs_add_free_space(cache, start, len);
6795                 }
6796
6797                 start += len;
6798                 total_unpinned += len;
6799                 space_info = cache->space_info;
6800
6801                 /*
6802                  * If this space cluster has been marked as fragmented and we've
6803                  * unpinned enough in this block group to potentially allow a
6804                  * cluster to be created inside of it go ahead and clear the
6805                  * fragmented check.
6806                  */
6807                 if (cluster && cluster->fragmented &&
6808                     total_unpinned > empty_cluster) {
6809                         spin_lock(&cluster->lock);
6810                         cluster->fragmented = 0;
6811                         spin_unlock(&cluster->lock);
6812                 }
6813
6814                 spin_lock(&space_info->lock);
6815                 spin_lock(&cache->lock);
6816                 cache->pinned -= len;
6817                 space_info->bytes_pinned -= len;
6818
6819                 trace_btrfs_space_reservation(fs_info, "pinned",
6820                                               space_info->flags, len, 0);
6821                 space_info->max_extent_size = 0;
6822                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6823                 if (cache->ro) {
6824                         space_info->bytes_readonly += len;
6825                         readonly = true;
6826                 }
6827                 spin_unlock(&cache->lock);
6828                 if (!readonly && return_free_space &&
6829                     global_rsv->space_info == space_info) {
6830                         u64 to_add = len;
6831
6832                         spin_lock(&global_rsv->lock);
6833                         if (!global_rsv->full) {
6834                                 to_add = min(len, global_rsv->size -
6835                                              global_rsv->reserved);
6836                                 global_rsv->reserved += to_add;
6837                                 space_info->bytes_may_use += to_add;
6838                                 if (global_rsv->reserved >= global_rsv->size)
6839                                         global_rsv->full = 1;
6840                                 trace_btrfs_space_reservation(fs_info,
6841                                                               "space_info",
6842                                                               space_info->flags,
6843                                                               to_add, 1);
6844                                 len -= to_add;
6845                         }
6846                         spin_unlock(&global_rsv->lock);
6847                         /* Add to any tickets we may have */
6848                         if (len)
6849                                 space_info_add_new_bytes(fs_info, space_info,
6850                                                          len);
6851                 }
6852                 spin_unlock(&space_info->lock);
6853         }
6854
6855         if (cache)
6856                 btrfs_put_block_group(cache);
6857         return 0;
6858 }
6859
6860 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6861                                struct btrfs_fs_info *fs_info)
6862 {
6863         struct btrfs_block_group_cache *block_group, *tmp;
6864         struct list_head *deleted_bgs;
6865         struct extent_io_tree *unpin;
6866         u64 start;
6867         u64 end;
6868         int ret;
6869
6870         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6871                 unpin = &fs_info->freed_extents[1];
6872         else
6873                 unpin = &fs_info->freed_extents[0];
6874
6875         while (!trans->aborted) {
6876                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6877                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6878                                             EXTENT_DIRTY, NULL);
6879                 if (ret) {
6880                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6881                         break;
6882                 }
6883
6884                 if (btrfs_test_opt(fs_info, DISCARD))
6885                         ret = btrfs_discard_extent(fs_info, start,
6886                                                    end + 1 - start, NULL);
6887
6888                 clear_extent_dirty(unpin, start, end);
6889                 unpin_extent_range(fs_info, start, end, true);
6890                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6891                 cond_resched();
6892         }
6893
6894         /*
6895          * Transaction is finished.  We don't need the lock anymore.  We
6896          * do need to clean up the block groups in case of a transaction
6897          * abort.
6898          */
6899         deleted_bgs = &trans->transaction->deleted_bgs;
6900         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6901                 u64 trimmed = 0;
6902
6903                 ret = -EROFS;
6904                 if (!trans->aborted)
6905                         ret = btrfs_discard_extent(fs_info,
6906                                                    block_group->key.objectid,
6907                                                    block_group->key.offset,
6908                                                    &trimmed);
6909
6910                 list_del_init(&block_group->bg_list);
6911                 btrfs_put_block_group_trimming(block_group);
6912                 btrfs_put_block_group(block_group);
6913
6914                 if (ret) {
6915                         const char *errstr = btrfs_decode_error(ret);
6916                         btrfs_warn(fs_info,
6917                            "discard failed while removing blockgroup: errno=%d %s",
6918                                    ret, errstr);
6919                 }
6920         }
6921
6922         return 0;
6923 }
6924
6925 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6926                                 struct btrfs_fs_info *info,
6927                                 struct btrfs_delayed_ref_node *node, u64 parent,
6928                                 u64 root_objectid, u64 owner_objectid,
6929                                 u64 owner_offset, int refs_to_drop,
6930                                 struct btrfs_delayed_extent_op *extent_op)
6931 {
6932         struct btrfs_key key;
6933         struct btrfs_path *path;
6934         struct btrfs_root *extent_root = info->extent_root;
6935         struct extent_buffer *leaf;
6936         struct btrfs_extent_item *ei;
6937         struct btrfs_extent_inline_ref *iref;
6938         int ret;
6939         int is_data;
6940         int extent_slot = 0;
6941         int found_extent = 0;
6942         int num_to_del = 1;
6943         u32 item_size;
6944         u64 refs;
6945         u64 bytenr = node->bytenr;
6946         u64 num_bytes = node->num_bytes;
6947         int last_ref = 0;
6948         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
6949
6950         path = btrfs_alloc_path();
6951         if (!path)
6952                 return -ENOMEM;
6953
6954         path->reada = READA_FORWARD;
6955         path->leave_spinning = 1;
6956
6957         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6958         BUG_ON(!is_data && refs_to_drop != 1);
6959
6960         if (is_data)
6961                 skinny_metadata = 0;
6962
6963         ret = lookup_extent_backref(trans, info, path, &iref,
6964                                     bytenr, num_bytes, parent,
6965                                     root_objectid, owner_objectid,
6966                                     owner_offset);
6967         if (ret == 0) {
6968                 extent_slot = path->slots[0];
6969                 while (extent_slot >= 0) {
6970                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6971                                               extent_slot);
6972                         if (key.objectid != bytenr)
6973                                 break;
6974                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6975                             key.offset == num_bytes) {
6976                                 found_extent = 1;
6977                                 break;
6978                         }
6979                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6980                             key.offset == owner_objectid) {
6981                                 found_extent = 1;
6982                                 break;
6983                         }
6984                         if (path->slots[0] - extent_slot > 5)
6985                                 break;
6986                         extent_slot--;
6987                 }
6988 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6989                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6990                 if (found_extent && item_size < sizeof(*ei))
6991                         found_extent = 0;
6992 #endif
6993                 if (!found_extent) {
6994                         BUG_ON(iref);
6995                         ret = remove_extent_backref(trans, info, path, NULL,
6996                                                     refs_to_drop,
6997                                                     is_data, &last_ref);
6998                         if (ret) {
6999                                 btrfs_abort_transaction(trans, ret);
7000                                 goto out;
7001                         }
7002                         btrfs_release_path(path);
7003                         path->leave_spinning = 1;
7004
7005                         key.objectid = bytenr;
7006                         key.type = BTRFS_EXTENT_ITEM_KEY;
7007                         key.offset = num_bytes;
7008
7009                         if (!is_data && skinny_metadata) {
7010                                 key.type = BTRFS_METADATA_ITEM_KEY;
7011                                 key.offset = owner_objectid;
7012                         }
7013
7014                         ret = btrfs_search_slot(trans, extent_root,
7015                                                 &key, path, -1, 1);
7016                         if (ret > 0 && skinny_metadata && path->slots[0]) {
7017                                 /*
7018                                  * Couldn't find our skinny metadata item,
7019                                  * see if we have ye olde extent item.
7020                                  */
7021                                 path->slots[0]--;
7022                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
7023                                                       path->slots[0]);
7024                                 if (key.objectid == bytenr &&
7025                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
7026                                     key.offset == num_bytes)
7027                                         ret = 0;
7028                         }
7029
7030                         if (ret > 0 && skinny_metadata) {
7031                                 skinny_metadata = false;
7032                                 key.objectid = bytenr;
7033                                 key.type = BTRFS_EXTENT_ITEM_KEY;
7034                                 key.offset = num_bytes;
7035                                 btrfs_release_path(path);
7036                                 ret = btrfs_search_slot(trans, extent_root,
7037                                                         &key, path, -1, 1);
7038                         }
7039
7040                         if (ret) {
7041                                 btrfs_err(info,
7042                                           "umm, got %d back from search, was looking for %llu",
7043                                           ret, bytenr);
7044                                 if (ret > 0)
7045                                         btrfs_print_leaf(path->nodes[0]);
7046                         }
7047                         if (ret < 0) {
7048                                 btrfs_abort_transaction(trans, ret);
7049                                 goto out;
7050                         }
7051                         extent_slot = path->slots[0];
7052                 }
7053         } else if (WARN_ON(ret == -ENOENT)) {
7054                 btrfs_print_leaf(path->nodes[0]);
7055                 btrfs_err(info,
7056                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
7057                         bytenr, parent, root_objectid, owner_objectid,
7058                         owner_offset);
7059                 btrfs_abort_transaction(trans, ret);
7060                 goto out;
7061         } else {
7062                 btrfs_abort_transaction(trans, ret);
7063                 goto out;
7064         }
7065
7066         leaf = path->nodes[0];
7067         item_size = btrfs_item_size_nr(leaf, extent_slot);
7068 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
7069         if (item_size < sizeof(*ei)) {
7070                 BUG_ON(found_extent || extent_slot != path->slots[0]);
7071                 ret = convert_extent_item_v0(trans, info, path, owner_objectid,
7072                                              0);
7073                 if (ret < 0) {
7074                         btrfs_abort_transaction(trans, ret);
7075                         goto out;
7076                 }
7077
7078                 btrfs_release_path(path);
7079                 path->leave_spinning = 1;
7080
7081                 key.objectid = bytenr;
7082                 key.type = BTRFS_EXTENT_ITEM_KEY;
7083                 key.offset = num_bytes;
7084
7085                 ret = btrfs_search_slot(trans, extent_root, &key, path,
7086                                         -1, 1);
7087                 if (ret) {
7088                         btrfs_err(info,
7089                                   "umm, got %d back from search, was looking for %llu",
7090                                 ret, bytenr);
7091                         btrfs_print_leaf(path->nodes[0]);
7092                 }
7093                 if (ret < 0) {
7094                         btrfs_abort_transaction(trans, ret);
7095                         goto out;
7096                 }
7097
7098                 extent_slot = path->slots[0];
7099                 leaf = path->nodes[0];
7100                 item_size = btrfs_item_size_nr(leaf, extent_slot);
7101         }
7102 #endif
7103         BUG_ON(item_size < sizeof(*ei));
7104         ei = btrfs_item_ptr(leaf, extent_slot,
7105                             struct btrfs_extent_item);
7106         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
7107             key.type == BTRFS_EXTENT_ITEM_KEY) {
7108                 struct btrfs_tree_block_info *bi;
7109                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
7110                 bi = (struct btrfs_tree_block_info *)(ei + 1);
7111                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
7112         }
7113
7114         refs = btrfs_extent_refs(leaf, ei);
7115         if (refs < refs_to_drop) {
7116                 btrfs_err(info,
7117                           "trying to drop %d refs but we only have %Lu for bytenr %Lu",
7118                           refs_to_drop, refs, bytenr);
7119                 ret = -EINVAL;
7120                 btrfs_abort_transaction(trans, ret);
7121                 goto out;
7122         }
7123         refs -= refs_to_drop;
7124
7125         if (refs > 0) {
7126                 if (extent_op)
7127                         __run_delayed_extent_op(extent_op, leaf, ei);
7128                 /*
7129                  * In the case of inline back ref, reference count will
7130                  * be updated by remove_extent_backref
7131                  */
7132                 if (iref) {
7133                         BUG_ON(!found_extent);
7134                 } else {
7135                         btrfs_set_extent_refs(leaf, ei, refs);
7136                         btrfs_mark_buffer_dirty(leaf);
7137                 }
7138                 if (found_extent) {
7139                         ret = remove_extent_backref(trans, info, path,
7140                                                     iref, refs_to_drop,
7141                                                     is_data, &last_ref);
7142                         if (ret) {
7143                                 btrfs_abort_transaction(trans, ret);
7144                                 goto out;
7145                         }
7146                 }
7147         } else {
7148                 if (found_extent) {
7149                         BUG_ON(is_data && refs_to_drop !=
7150                                extent_data_ref_count(path, iref));
7151                         if (iref) {
7152                                 BUG_ON(path->slots[0] != extent_slot);
7153                         } else {
7154                                 BUG_ON(path->slots[0] != extent_slot + 1);
7155                                 path->slots[0] = extent_slot;
7156                                 num_to_del = 2;
7157                         }
7158                 }
7159
7160                 last_ref = 1;
7161                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
7162                                       num_to_del);
7163                 if (ret) {
7164                         btrfs_abort_transaction(trans, ret);
7165                         goto out;
7166                 }
7167                 btrfs_release_path(path);
7168
7169                 if (is_data) {
7170                         ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
7171                         if (ret) {
7172                                 btrfs_abort_transaction(trans, ret);
7173                                 goto out;
7174                         }
7175                 }
7176
7177                 ret = add_to_free_space_tree(trans, info, bytenr, num_bytes);
7178                 if (ret) {
7179                         btrfs_abort_transaction(trans, ret);
7180                         goto out;
7181                 }
7182
7183                 ret = update_block_group(trans, info, bytenr, num_bytes, 0);
7184                 if (ret) {
7185                         btrfs_abort_transaction(trans, ret);
7186                         goto out;
7187                 }
7188         }
7189         btrfs_release_path(path);
7190
7191 out:
7192         btrfs_free_path(path);
7193         return ret;
7194 }
7195
7196 /*
7197  * when we free an block, it is possible (and likely) that we free the last
7198  * delayed ref for that extent as well.  This searches the delayed ref tree for
7199  * a given extent, and if there are no other delayed refs to be processed, it
7200  * removes it from the tree.
7201  */
7202 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
7203                                       u64 bytenr)
7204 {
7205         struct btrfs_delayed_ref_head *head;
7206         struct btrfs_delayed_ref_root *delayed_refs;
7207         int ret = 0;
7208
7209         delayed_refs = &trans->transaction->delayed_refs;
7210         spin_lock(&delayed_refs->lock);
7211         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
7212         if (!head)
7213                 goto out_delayed_unlock;
7214
7215         spin_lock(&head->lock);
7216         if (!list_empty(&head->ref_list))
7217                 goto out;
7218
7219         if (head->extent_op) {
7220                 if (!head->must_insert_reserved)
7221                         goto out;
7222                 btrfs_free_delayed_extent_op(head->extent_op);
7223                 head->extent_op = NULL;
7224         }
7225
7226         /*
7227          * waiting for the lock here would deadlock.  If someone else has it
7228          * locked they are already in the process of dropping it anyway
7229          */
7230         if (!mutex_trylock(&head->mutex))
7231                 goto out;
7232
7233         /*
7234          * at this point we have a head with no other entries.  Go
7235          * ahead and process it.
7236          */
7237         head->node.in_tree = 0;
7238         rb_erase(&head->href_node, &delayed_refs->href_root);
7239
7240         atomic_dec(&delayed_refs->num_entries);
7241
7242         /*
7243          * we don't take a ref on the node because we're removing it from the
7244          * tree, so we just steal the ref the tree was holding.
7245          */
7246         delayed_refs->num_heads--;
7247         if (head->processing == 0)
7248                 delayed_refs->num_heads_ready--;
7249         head->processing = 0;
7250         spin_unlock(&head->lock);
7251         spin_unlock(&delayed_refs->lock);
7252
7253         BUG_ON(head->extent_op);
7254         if (head->must_insert_reserved)
7255                 ret = 1;
7256
7257         mutex_unlock(&head->mutex);
7258         btrfs_put_delayed_ref(&head->node);
7259         return ret;
7260 out:
7261         spin_unlock(&head->lock);
7262
7263 out_delayed_unlock:
7264         spin_unlock(&delayed_refs->lock);
7265         return 0;
7266 }
7267
7268 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7269                            struct btrfs_root *root,
7270                            struct extent_buffer *buf,
7271                            u64 parent, int last_ref)
7272 {
7273         struct btrfs_fs_info *fs_info = root->fs_info;
7274         int pin = 1;
7275         int ret;
7276
7277         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7278                 int old_ref_mod, new_ref_mod;
7279
7280                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, buf->start,
7281                                                  buf->len, parent,
7282                                                  root->root_key.objectid,
7283                                                  btrfs_header_level(buf),
7284                                                  BTRFS_DROP_DELAYED_REF, NULL,
7285                                                  &old_ref_mod, &new_ref_mod);
7286                 BUG_ON(ret); /* -ENOMEM */
7287                 pin = old_ref_mod >= 0 && new_ref_mod < 0;
7288         }
7289
7290         if (last_ref && btrfs_header_generation(buf) == trans->transid) {
7291                 struct btrfs_block_group_cache *cache;
7292
7293                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7294                         ret = check_ref_cleanup(trans, buf->start);
7295                         if (!ret)
7296                                 goto out;
7297                 }
7298
7299                 pin = 0;
7300                 cache = btrfs_lookup_block_group(fs_info, buf->start);
7301
7302                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7303                         pin_down_extent(fs_info, cache, buf->start,
7304                                         buf->len, 1);
7305                         btrfs_put_block_group(cache);
7306                         goto out;
7307                 }
7308
7309                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7310
7311                 btrfs_add_free_space(cache, buf->start, buf->len);
7312                 btrfs_free_reserved_bytes(cache, buf->len, 0);
7313                 btrfs_put_block_group(cache);
7314                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
7315         }
7316 out:
7317         if (pin)
7318                 add_pinned_bytes(fs_info, buf->len, btrfs_header_level(buf),
7319                                  root->root_key.objectid);
7320
7321         if (last_ref) {
7322                 /*
7323                  * Deleting the buffer, clear the corrupt flag since it doesn't
7324                  * matter anymore.
7325                  */
7326                 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7327         }
7328 }
7329
7330 /* Can return -ENOMEM */
7331 int btrfs_free_extent(struct btrfs_trans_handle *trans,
7332                       struct btrfs_fs_info *fs_info,
7333                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7334                       u64 owner, u64 offset)
7335 {
7336         int old_ref_mod, new_ref_mod;
7337         int ret;
7338
7339         if (btrfs_is_testing(fs_info))
7340                 return 0;
7341
7342
7343         /*
7344          * tree log blocks never actually go into the extent allocation
7345          * tree, just update pinning info and exit early.
7346          */
7347         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7348                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7349                 /* unlocks the pinned mutex */
7350                 btrfs_pin_extent(fs_info, bytenr, num_bytes, 1);
7351                 old_ref_mod = new_ref_mod = 0;
7352                 ret = 0;
7353         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7354                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7355                                                  num_bytes, parent,
7356                                                  root_objectid, (int)owner,
7357                                                  BTRFS_DROP_DELAYED_REF, NULL,
7358                                                  &old_ref_mod, &new_ref_mod);
7359         } else {
7360                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7361                                                  num_bytes, parent,
7362                                                  root_objectid, owner, offset,
7363                                                  0, BTRFS_DROP_DELAYED_REF,
7364                                                  &old_ref_mod, &new_ref_mod);
7365         }
7366
7367         if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0)
7368                 add_pinned_bytes(fs_info, num_bytes, owner, root_objectid);
7369
7370         return ret;
7371 }
7372
7373 /*
7374  * when we wait for progress in the block group caching, its because
7375  * our allocation attempt failed at least once.  So, we must sleep
7376  * and let some progress happen before we try again.
7377  *
7378  * This function will sleep at least once waiting for new free space to
7379  * show up, and then it will check the block group free space numbers
7380  * for our min num_bytes.  Another option is to have it go ahead
7381  * and look in the rbtree for a free extent of a given size, but this
7382  * is a good start.
7383  *
7384  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7385  * any of the information in this block group.
7386  */
7387 static noinline void
7388 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7389                                 u64 num_bytes)
7390 {
7391         struct btrfs_caching_control *caching_ctl;
7392
7393         caching_ctl = get_caching_control(cache);
7394         if (!caching_ctl)
7395                 return;
7396
7397         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7398                    (cache->free_space_ctl->free_space >= num_bytes));
7399
7400         put_caching_control(caching_ctl);
7401 }
7402
7403 static noinline int
7404 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7405 {
7406         struct btrfs_caching_control *caching_ctl;
7407         int ret = 0;
7408
7409         caching_ctl = get_caching_control(cache);
7410         if (!caching_ctl)
7411                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7412
7413         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7414         if (cache->cached == BTRFS_CACHE_ERROR)
7415                 ret = -EIO;
7416         put_caching_control(caching_ctl);
7417         return ret;
7418 }
7419
7420 int __get_raid_index(u64 flags)
7421 {
7422         if (flags & BTRFS_BLOCK_GROUP_RAID10)
7423                 return BTRFS_RAID_RAID10;
7424         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
7425                 return BTRFS_RAID_RAID1;
7426         else if (flags & BTRFS_BLOCK_GROUP_DUP)
7427                 return BTRFS_RAID_DUP;
7428         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
7429                 return BTRFS_RAID_RAID0;
7430         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
7431                 return BTRFS_RAID_RAID5;
7432         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
7433                 return BTRFS_RAID_RAID6;
7434
7435         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
7436 }
7437
7438 int get_block_group_index(struct btrfs_block_group_cache *cache)
7439 {
7440         return __get_raid_index(cache->flags);
7441 }
7442
7443 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
7444         [BTRFS_RAID_RAID10]     = "raid10",
7445         [BTRFS_RAID_RAID1]      = "raid1",
7446         [BTRFS_RAID_DUP]        = "dup",
7447         [BTRFS_RAID_RAID0]      = "raid0",
7448         [BTRFS_RAID_SINGLE]     = "single",
7449         [BTRFS_RAID_RAID5]      = "raid5",
7450         [BTRFS_RAID_RAID6]      = "raid6",
7451 };
7452
7453 static const char *get_raid_name(enum btrfs_raid_types type)
7454 {
7455         if (type >= BTRFS_NR_RAID_TYPES)
7456                 return NULL;
7457
7458         return btrfs_raid_type_names[type];
7459 }
7460
7461 enum btrfs_loop_type {
7462         LOOP_CACHING_NOWAIT = 0,
7463         LOOP_CACHING_WAIT = 1,
7464         LOOP_ALLOC_CHUNK = 2,
7465         LOOP_NO_EMPTY_SIZE = 3,
7466 };
7467
7468 static inline void
7469 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7470                        int delalloc)
7471 {
7472         if (delalloc)
7473                 down_read(&cache->data_rwsem);
7474 }
7475
7476 static inline void
7477 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7478                        int delalloc)
7479 {
7480         btrfs_get_block_group(cache);
7481         if (delalloc)
7482                 down_read(&cache->data_rwsem);
7483 }
7484
7485 static struct btrfs_block_group_cache *
7486 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7487                    struct btrfs_free_cluster *cluster,
7488                    int delalloc)
7489 {
7490         struct btrfs_block_group_cache *used_bg = NULL;
7491
7492         spin_lock(&cluster->refill_lock);
7493         while (1) {
7494                 used_bg = cluster->block_group;
7495                 if (!used_bg)
7496                         return NULL;
7497
7498                 if (used_bg == block_group)
7499                         return used_bg;
7500
7501                 btrfs_get_block_group(used_bg);
7502
7503                 if (!delalloc)
7504                         return used_bg;
7505
7506                 if (down_read_trylock(&used_bg->data_rwsem))
7507                         return used_bg;
7508
7509                 spin_unlock(&cluster->refill_lock);
7510
7511                 /* We should only have one-level nested. */
7512                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
7513
7514                 spin_lock(&cluster->refill_lock);
7515                 if (used_bg == cluster->block_group)
7516                         return used_bg;
7517
7518                 up_read(&used_bg->data_rwsem);
7519                 btrfs_put_block_group(used_bg);
7520         }
7521 }
7522
7523 static inline void
7524 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7525                          int delalloc)
7526 {
7527         if (delalloc)
7528                 up_read(&cache->data_rwsem);
7529         btrfs_put_block_group(cache);
7530 }
7531
7532 /*
7533  * walks the btree of allocated extents and find a hole of a given size.
7534  * The key ins is changed to record the hole:
7535  * ins->objectid == start position
7536  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7537  * ins->offset == the size of the hole.
7538  * Any available blocks before search_start are skipped.
7539  *
7540  * If there is no suitable free space, we will record the max size of
7541  * the free space extent currently.
7542  */
7543 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
7544                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7545                                 u64 hint_byte, struct btrfs_key *ins,
7546                                 u64 flags, int delalloc)
7547 {
7548         int ret = 0;
7549         struct btrfs_root *root = fs_info->extent_root;
7550         struct btrfs_free_cluster *last_ptr = NULL;
7551         struct btrfs_block_group_cache *block_group = NULL;
7552         u64 search_start = 0;
7553         u64 max_extent_size = 0;
7554         u64 empty_cluster = 0;
7555         struct btrfs_space_info *space_info;
7556         int loop = 0;
7557         int index = __get_raid_index(flags);
7558         bool failed_cluster_refill = false;
7559         bool failed_alloc = false;
7560         bool use_cluster = true;
7561         bool have_caching_bg = false;
7562         bool orig_have_caching_bg = false;
7563         bool full_search = false;
7564
7565         WARN_ON(num_bytes < fs_info->sectorsize);
7566         ins->type = BTRFS_EXTENT_ITEM_KEY;
7567         ins->objectid = 0;
7568         ins->offset = 0;
7569
7570         trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
7571
7572         space_info = __find_space_info(fs_info, flags);
7573         if (!space_info) {
7574                 btrfs_err(fs_info, "No space info for %llu", flags);
7575                 return -ENOSPC;
7576         }
7577
7578         /*
7579          * If our free space is heavily fragmented we may not be able to make
7580          * big contiguous allocations, so instead of doing the expensive search
7581          * for free space, simply return ENOSPC with our max_extent_size so we
7582          * can go ahead and search for a more manageable chunk.
7583          *
7584          * If our max_extent_size is large enough for our allocation simply
7585          * disable clustering since we will likely not be able to find enough
7586          * space to create a cluster and induce latency trying.
7587          */
7588         if (unlikely(space_info->max_extent_size)) {
7589                 spin_lock(&space_info->lock);
7590                 if (space_info->max_extent_size &&
7591                     num_bytes > space_info->max_extent_size) {
7592                         ins->offset = space_info->max_extent_size;
7593                         spin_unlock(&space_info->lock);
7594                         return -ENOSPC;
7595                 } else if (space_info->max_extent_size) {
7596                         use_cluster = false;
7597                 }
7598                 spin_unlock(&space_info->lock);
7599         }
7600
7601         last_ptr = fetch_cluster_info(fs_info, space_info, &empty_cluster);
7602         if (last_ptr) {
7603                 spin_lock(&last_ptr->lock);
7604                 if (last_ptr->block_group)
7605                         hint_byte = last_ptr->window_start;
7606                 if (last_ptr->fragmented) {
7607                         /*
7608                          * We still set window_start so we can keep track of the
7609                          * last place we found an allocation to try and save
7610                          * some time.
7611                          */
7612                         hint_byte = last_ptr->window_start;
7613                         use_cluster = false;
7614                 }
7615                 spin_unlock(&last_ptr->lock);
7616         }
7617
7618         search_start = max(search_start, first_logical_byte(fs_info, 0));
7619         search_start = max(search_start, hint_byte);
7620         if (search_start == hint_byte) {
7621                 block_group = btrfs_lookup_block_group(fs_info, search_start);
7622                 /*
7623                  * we don't want to use the block group if it doesn't match our
7624                  * allocation bits, or if its not cached.
7625                  *
7626                  * However if we are re-searching with an ideal block group
7627                  * picked out then we don't care that the block group is cached.
7628                  */
7629                 if (block_group && block_group_bits(block_group, flags) &&
7630                     block_group->cached != BTRFS_CACHE_NO) {
7631                         down_read(&space_info->groups_sem);
7632                         if (list_empty(&block_group->list) ||
7633                             block_group->ro) {
7634                                 /*
7635                                  * someone is removing this block group,
7636                                  * we can't jump into the have_block_group
7637                                  * target because our list pointers are not
7638                                  * valid
7639                                  */
7640                                 btrfs_put_block_group(block_group);
7641                                 up_read(&space_info->groups_sem);
7642                         } else {
7643                                 index = get_block_group_index(block_group);
7644                                 btrfs_lock_block_group(block_group, delalloc);
7645                                 goto have_block_group;
7646                         }
7647                 } else if (block_group) {
7648                         btrfs_put_block_group(block_group);
7649                 }
7650         }
7651 search:
7652         have_caching_bg = false;
7653         if (index == 0 || index == __get_raid_index(flags))
7654                 full_search = true;
7655         down_read(&space_info->groups_sem);
7656         list_for_each_entry(block_group, &space_info->block_groups[index],
7657                             list) {
7658                 u64 offset;
7659                 int cached;
7660
7661                 /* If the block group is read-only, we can skip it entirely. */
7662                 if (unlikely(block_group->ro))
7663                         continue;
7664
7665                 btrfs_grab_block_group(block_group, delalloc);
7666                 search_start = block_group->key.objectid;
7667
7668                 /*
7669                  * this can happen if we end up cycling through all the
7670                  * raid types, but we want to make sure we only allocate
7671                  * for the proper type.
7672                  */
7673                 if (!block_group_bits(block_group, flags)) {
7674                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
7675                                 BTRFS_BLOCK_GROUP_RAID1 |
7676                                 BTRFS_BLOCK_GROUP_RAID5 |
7677                                 BTRFS_BLOCK_GROUP_RAID6 |
7678                                 BTRFS_BLOCK_GROUP_RAID10;
7679
7680                         /*
7681                          * if they asked for extra copies and this block group
7682                          * doesn't provide them, bail.  This does allow us to
7683                          * fill raid0 from raid1.
7684                          */
7685                         if ((flags & extra) && !(block_group->flags & extra))
7686                                 goto loop;
7687                 }
7688
7689 have_block_group:
7690                 cached = block_group_cache_done(block_group);
7691                 if (unlikely(!cached)) {
7692                         have_caching_bg = true;
7693                         ret = cache_block_group(block_group, 0);
7694                         BUG_ON(ret < 0);
7695                         ret = 0;
7696                 }
7697
7698                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7699                         goto loop;
7700
7701                 /*
7702                  * Ok we want to try and use the cluster allocator, so
7703                  * lets look there
7704                  */
7705                 if (last_ptr && use_cluster) {
7706                         struct btrfs_block_group_cache *used_block_group;
7707                         unsigned long aligned_cluster;
7708                         /*
7709                          * the refill lock keeps out other
7710                          * people trying to start a new cluster
7711                          */
7712                         used_block_group = btrfs_lock_cluster(block_group,
7713                                                               last_ptr,
7714                                                               delalloc);
7715                         if (!used_block_group)
7716                                 goto refill_cluster;
7717
7718                         if (used_block_group != block_group &&
7719                             (used_block_group->ro ||
7720                              !block_group_bits(used_block_group, flags)))
7721                                 goto release_cluster;
7722
7723                         offset = btrfs_alloc_from_cluster(used_block_group,
7724                                                 last_ptr,
7725                                                 num_bytes,
7726                                                 used_block_group->key.objectid,
7727                                                 &max_extent_size);
7728                         if (offset) {
7729                                 /* we have a block, we're done */
7730                                 spin_unlock(&last_ptr->refill_lock);
7731                                 trace_btrfs_reserve_extent_cluster(fs_info,
7732                                                 used_block_group,
7733                                                 search_start, num_bytes);
7734                                 if (used_block_group != block_group) {
7735                                         btrfs_release_block_group(block_group,
7736                                                                   delalloc);
7737                                         block_group = used_block_group;
7738                                 }
7739                                 goto checks;
7740                         }
7741
7742                         WARN_ON(last_ptr->block_group != used_block_group);
7743 release_cluster:
7744                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7745                          * set up a new clusters, so lets just skip it
7746                          * and let the allocator find whatever block
7747                          * it can find.  If we reach this point, we
7748                          * will have tried the cluster allocator
7749                          * plenty of times and not have found
7750                          * anything, so we are likely way too
7751                          * fragmented for the clustering stuff to find
7752                          * anything.
7753                          *
7754                          * However, if the cluster is taken from the
7755                          * current block group, release the cluster
7756                          * first, so that we stand a better chance of
7757                          * succeeding in the unclustered
7758                          * allocation.  */
7759                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7760                             used_block_group != block_group) {
7761                                 spin_unlock(&last_ptr->refill_lock);
7762                                 btrfs_release_block_group(used_block_group,
7763                                                           delalloc);
7764                                 goto unclustered_alloc;
7765                         }
7766
7767                         /*
7768                          * this cluster didn't work out, free it and
7769                          * start over
7770                          */
7771                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7772
7773                         if (used_block_group != block_group)
7774                                 btrfs_release_block_group(used_block_group,
7775                                                           delalloc);
7776 refill_cluster:
7777                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7778                                 spin_unlock(&last_ptr->refill_lock);
7779                                 goto unclustered_alloc;
7780                         }
7781
7782                         aligned_cluster = max_t(unsigned long,
7783                                                 empty_cluster + empty_size,
7784                                               block_group->full_stripe_len);
7785
7786                         /* allocate a cluster in this block group */
7787                         ret = btrfs_find_space_cluster(fs_info, block_group,
7788                                                        last_ptr, search_start,
7789                                                        num_bytes,
7790                                                        aligned_cluster);
7791                         if (ret == 0) {
7792                                 /*
7793                                  * now pull our allocation out of this
7794                                  * cluster
7795                                  */
7796                                 offset = btrfs_alloc_from_cluster(block_group,
7797                                                         last_ptr,
7798                                                         num_bytes,
7799                                                         search_start,
7800                                                         &max_extent_size);
7801                                 if (offset) {
7802                                         /* we found one, proceed */
7803                                         spin_unlock(&last_ptr->refill_lock);
7804                                         trace_btrfs_reserve_extent_cluster(fs_info,
7805                                                 block_group, search_start,
7806                                                 num_bytes);
7807                                         goto checks;
7808                                 }
7809                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7810                                    && !failed_cluster_refill) {
7811                                 spin_unlock(&last_ptr->refill_lock);
7812
7813                                 failed_cluster_refill = true;
7814                                 wait_block_group_cache_progress(block_group,
7815                                        num_bytes + empty_cluster + empty_size);
7816                                 goto have_block_group;
7817                         }
7818
7819                         /*
7820                          * at this point we either didn't find a cluster
7821                          * or we weren't able to allocate a block from our
7822                          * cluster.  Free the cluster we've been trying
7823                          * to use, and go to the next block group
7824                          */
7825                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7826                         spin_unlock(&last_ptr->refill_lock);
7827                         goto loop;
7828                 }
7829
7830 unclustered_alloc:
7831                 /*
7832                  * We are doing an unclustered alloc, set the fragmented flag so
7833                  * we don't bother trying to setup a cluster again until we get
7834                  * more space.
7835                  */
7836                 if (unlikely(last_ptr)) {
7837                         spin_lock(&last_ptr->lock);
7838                         last_ptr->fragmented = 1;
7839                         spin_unlock(&last_ptr->lock);
7840                 }
7841                 if (cached) {
7842                         struct btrfs_free_space_ctl *ctl =
7843                                 block_group->free_space_ctl;
7844
7845                         spin_lock(&ctl->tree_lock);
7846                         if (ctl->free_space <
7847                             num_bytes + empty_cluster + empty_size) {
7848                                 if (ctl->free_space > max_extent_size)
7849                                         max_extent_size = ctl->free_space;
7850                                 spin_unlock(&ctl->tree_lock);
7851                                 goto loop;
7852                         }
7853                         spin_unlock(&ctl->tree_lock);
7854                 }
7855
7856                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7857                                                     num_bytes, empty_size,
7858                                                     &max_extent_size);
7859                 /*
7860                  * If we didn't find a chunk, and we haven't failed on this
7861                  * block group before, and this block group is in the middle of
7862                  * caching and we are ok with waiting, then go ahead and wait
7863                  * for progress to be made, and set failed_alloc to true.
7864                  *
7865                  * If failed_alloc is true then we've already waited on this
7866                  * block group once and should move on to the next block group.
7867                  */
7868                 if (!offset && !failed_alloc && !cached &&
7869                     loop > LOOP_CACHING_NOWAIT) {
7870                         wait_block_group_cache_progress(block_group,
7871                                                 num_bytes + empty_size);
7872                         failed_alloc = true;
7873                         goto have_block_group;
7874                 } else if (!offset) {
7875                         goto loop;
7876                 }
7877 checks:
7878                 search_start = ALIGN(offset, fs_info->stripesize);
7879
7880                 /* move on to the next group */
7881                 if (search_start + num_bytes >
7882                     block_group->key.objectid + block_group->key.offset) {
7883                         btrfs_add_free_space(block_group, offset, num_bytes);
7884                         goto loop;
7885                 }
7886
7887                 if (offset < search_start)
7888                         btrfs_add_free_space(block_group, offset,
7889                                              search_start - offset);
7890                 BUG_ON(offset > search_start);
7891
7892                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7893                                 num_bytes, delalloc);
7894                 if (ret == -EAGAIN) {
7895                         btrfs_add_free_space(block_group, offset, num_bytes);
7896                         goto loop;
7897                 }
7898                 btrfs_inc_block_group_reservations(block_group);
7899
7900                 /* we are all good, lets return */
7901                 ins->objectid = search_start;
7902                 ins->offset = num_bytes;
7903
7904                 trace_btrfs_reserve_extent(fs_info, block_group,
7905                                            search_start, num_bytes);
7906                 btrfs_release_block_group(block_group, delalloc);
7907                 break;
7908 loop:
7909                 failed_cluster_refill = false;
7910                 failed_alloc = false;
7911                 BUG_ON(index != get_block_group_index(block_group));
7912                 btrfs_release_block_group(block_group, delalloc);
7913                 cond_resched();
7914         }
7915         up_read(&space_info->groups_sem);
7916
7917         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7918                 && !orig_have_caching_bg)
7919                 orig_have_caching_bg = true;
7920
7921         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7922                 goto search;
7923
7924         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7925                 goto search;
7926
7927         /*
7928          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7929          *                      caching kthreads as we move along
7930          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7931          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7932          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7933          *                      again
7934          */
7935         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7936                 index = 0;
7937                 if (loop == LOOP_CACHING_NOWAIT) {
7938                         /*
7939                          * We want to skip the LOOP_CACHING_WAIT step if we
7940                          * don't have any uncached bgs and we've already done a
7941                          * full search through.
7942                          */
7943                         if (orig_have_caching_bg || !full_search)
7944                                 loop = LOOP_CACHING_WAIT;
7945                         else
7946                                 loop = LOOP_ALLOC_CHUNK;
7947                 } else {
7948                         loop++;
7949                 }
7950
7951                 if (loop == LOOP_ALLOC_CHUNK) {
7952                         struct btrfs_trans_handle *trans;
7953                         int exist = 0;
7954
7955                         trans = current->journal_info;
7956                         if (trans)
7957                                 exist = 1;
7958                         else
7959                                 trans = btrfs_join_transaction(root);
7960
7961                         if (IS_ERR(trans)) {
7962                                 ret = PTR_ERR(trans);
7963                                 goto out;
7964                         }
7965
7966                         ret = do_chunk_alloc(trans, fs_info, flags,
7967                                              CHUNK_ALLOC_FORCE);
7968
7969                         /*
7970                          * If we can't allocate a new chunk we've already looped
7971                          * through at least once, move on to the NO_EMPTY_SIZE
7972                          * case.
7973                          */
7974                         if (ret == -ENOSPC)
7975                                 loop = LOOP_NO_EMPTY_SIZE;
7976
7977                         /*
7978                          * Do not bail out on ENOSPC since we
7979                          * can do more things.
7980                          */
7981                         if (ret < 0 && ret != -ENOSPC)
7982                                 btrfs_abort_transaction(trans, ret);
7983                         else
7984                                 ret = 0;
7985                         if (!exist)
7986                                 btrfs_end_transaction(trans);
7987                         if (ret)
7988                                 goto out;
7989                 }
7990
7991                 if (loop == LOOP_NO_EMPTY_SIZE) {
7992                         /*
7993                          * Don't loop again if we already have no empty_size and
7994                          * no empty_cluster.
7995                          */
7996                         if (empty_size == 0 &&
7997                             empty_cluster == 0) {
7998                                 ret = -ENOSPC;
7999                                 goto out;
8000                         }
8001                         empty_size = 0;
8002                         empty_cluster = 0;
8003                 }
8004
8005                 goto search;
8006         } else if (!ins->objectid) {
8007                 ret = -ENOSPC;
8008         } else if (ins->objectid) {
8009                 if (!use_cluster && last_ptr) {
8010                         spin_lock(&last_ptr->lock);
8011                         last_ptr->window_start = ins->objectid;
8012                         spin_unlock(&last_ptr->lock);
8013                 }
8014                 ret = 0;
8015         }
8016 out:
8017         if (ret == -ENOSPC) {
8018                 spin_lock(&space_info->lock);
8019                 space_info->max_extent_size = max_extent_size;
8020                 spin_unlock(&space_info->lock);
8021                 ins->offset = max_extent_size;
8022         }
8023         return ret;
8024 }
8025
8026 static void dump_space_info(struct btrfs_fs_info *fs_info,
8027                             struct btrfs_space_info *info, u64 bytes,
8028                             int dump_block_groups)
8029 {
8030         struct btrfs_block_group_cache *cache;
8031         int index = 0;
8032
8033         spin_lock(&info->lock);
8034         btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
8035                    info->flags,
8036                    info->total_bytes - btrfs_space_info_used(info, true),
8037                    info->full ? "" : "not ");
8038         btrfs_info(fs_info,
8039                 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
8040                 info->total_bytes, info->bytes_used, info->bytes_pinned,
8041                 info->bytes_reserved, info->bytes_may_use,
8042                 info->bytes_readonly);
8043         spin_unlock(&info->lock);
8044
8045         if (!dump_block_groups)
8046                 return;
8047
8048         down_read(&info->groups_sem);
8049 again:
8050         list_for_each_entry(cache, &info->block_groups[index], list) {
8051                 spin_lock(&cache->lock);
8052                 btrfs_info(fs_info,
8053                         "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
8054                         cache->key.objectid, cache->key.offset,
8055                         btrfs_block_group_used(&cache->item), cache->pinned,
8056                         cache->reserved, cache->ro ? "[readonly]" : "");
8057                 btrfs_dump_free_space(cache, bytes);
8058                 spin_unlock(&cache->lock);
8059         }
8060         if (++index < BTRFS_NR_RAID_TYPES)
8061                 goto again;
8062         up_read(&info->groups_sem);
8063 }
8064
8065 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
8066                          u64 num_bytes, u64 min_alloc_size,
8067                          u64 empty_size, u64 hint_byte,
8068                          struct btrfs_key *ins, int is_data, int delalloc)
8069 {
8070         struct btrfs_fs_info *fs_info = root->fs_info;
8071         bool final_tried = num_bytes == min_alloc_size;
8072         u64 flags;
8073         int ret;
8074
8075         flags = get_alloc_profile_by_root(root, is_data);
8076 again:
8077         WARN_ON(num_bytes < fs_info->sectorsize);
8078         ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
8079                                hint_byte, ins, flags, delalloc);
8080         if (!ret && !is_data) {
8081                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
8082         } else if (ret == -ENOSPC) {
8083                 if (!final_tried && ins->offset) {
8084                         num_bytes = min(num_bytes >> 1, ins->offset);
8085                         num_bytes = round_down(num_bytes,
8086                                                fs_info->sectorsize);
8087                         num_bytes = max(num_bytes, min_alloc_size);
8088                         ram_bytes = num_bytes;
8089                         if (num_bytes == min_alloc_size)
8090                                 final_tried = true;
8091                         goto again;
8092                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8093                         struct btrfs_space_info *sinfo;
8094
8095                         sinfo = __find_space_info(fs_info, flags);
8096                         btrfs_err(fs_info,
8097                                   "allocation failed flags %llu, wanted %llu",
8098                                   flags, num_bytes);
8099                         if (sinfo)
8100                                 dump_space_info(fs_info, sinfo, num_bytes, 1);
8101                 }
8102         }
8103
8104         return ret;
8105 }
8106
8107 static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8108                                         u64 start, u64 len,
8109                                         int pin, int delalloc)
8110 {
8111         struct btrfs_block_group_cache *cache;
8112         int ret = 0;
8113
8114         cache = btrfs_lookup_block_group(fs_info, start);
8115         if (!cache) {
8116                 btrfs_err(fs_info, "Unable to find block group for %llu",
8117                           start);
8118                 return -ENOSPC;
8119         }
8120
8121         if (pin)
8122                 pin_down_extent(fs_info, cache, start, len, 1);
8123         else {
8124                 if (btrfs_test_opt(fs_info, DISCARD))
8125                         ret = btrfs_discard_extent(fs_info, start, len, NULL);
8126                 btrfs_add_free_space(cache, start, len);
8127                 btrfs_free_reserved_bytes(cache, len, delalloc);
8128                 trace_btrfs_reserved_extent_free(fs_info, start, len);
8129         }
8130
8131         btrfs_put_block_group(cache);
8132         return ret;
8133 }
8134
8135 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8136                                u64 start, u64 len, int delalloc)
8137 {
8138         return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
8139 }
8140
8141 int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
8142                                        u64 start, u64 len)
8143 {
8144         return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
8145 }
8146
8147 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8148                                       struct btrfs_fs_info *fs_info,
8149                                       u64 parent, u64 root_objectid,
8150                                       u64 flags, u64 owner, u64 offset,
8151                                       struct btrfs_key *ins, int ref_mod)
8152 {
8153         int ret;
8154         struct btrfs_extent_item *extent_item;
8155         struct btrfs_extent_inline_ref *iref;
8156         struct btrfs_path *path;
8157         struct extent_buffer *leaf;
8158         int type;
8159         u32 size;
8160
8161         if (parent > 0)
8162                 type = BTRFS_SHARED_DATA_REF_KEY;
8163         else
8164                 type = BTRFS_EXTENT_DATA_REF_KEY;
8165
8166         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8167
8168         path = btrfs_alloc_path();
8169         if (!path)
8170                 return -ENOMEM;
8171
8172         path->leave_spinning = 1;
8173         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8174                                       ins, size);
8175         if (ret) {
8176                 btrfs_free_path(path);
8177                 return ret;
8178         }
8179
8180         leaf = path->nodes[0];
8181         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8182                                      struct btrfs_extent_item);
8183         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8184         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8185         btrfs_set_extent_flags(leaf, extent_item,
8186                                flags | BTRFS_EXTENT_FLAG_DATA);
8187
8188         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8189         btrfs_set_extent_inline_ref_type(leaf, iref, type);
8190         if (parent > 0) {
8191                 struct btrfs_shared_data_ref *ref;
8192                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8193                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8194                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8195         } else {
8196                 struct btrfs_extent_data_ref *ref;
8197                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8198                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8199                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8200                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8201                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8202         }
8203
8204         btrfs_mark_buffer_dirty(path->nodes[0]);
8205         btrfs_free_path(path);
8206
8207         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8208                                           ins->offset);
8209         if (ret)
8210                 return ret;
8211
8212         ret = update_block_group(trans, fs_info, ins->objectid, ins->offset, 1);
8213         if (ret) { /* -ENOENT, logic error */
8214                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8215                         ins->objectid, ins->offset);
8216                 BUG();
8217         }
8218         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
8219         return ret;
8220 }
8221
8222 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8223                                      struct btrfs_fs_info *fs_info,
8224                                      u64 parent, u64 root_objectid,
8225                                      u64 flags, struct btrfs_disk_key *key,
8226                                      int level, struct btrfs_key *ins)
8227 {
8228         int ret;
8229         struct btrfs_extent_item *extent_item;
8230         struct btrfs_tree_block_info *block_info;
8231         struct btrfs_extent_inline_ref *iref;
8232         struct btrfs_path *path;
8233         struct extent_buffer *leaf;
8234         u32 size = sizeof(*extent_item) + sizeof(*iref);
8235         u64 num_bytes = ins->offset;
8236         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8237
8238         if (!skinny_metadata)
8239                 size += sizeof(*block_info);
8240
8241         path = btrfs_alloc_path();
8242         if (!path) {
8243                 btrfs_free_and_pin_reserved_extent(fs_info, ins->objectid,
8244                                                    fs_info->nodesize);
8245                 return -ENOMEM;
8246         }
8247
8248         path->leave_spinning = 1;
8249         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8250                                       ins, size);
8251         if (ret) {
8252                 btrfs_free_path(path);
8253                 btrfs_free_and_pin_reserved_extent(fs_info, ins->objectid,
8254                                                    fs_info->nodesize);
8255                 return ret;
8256         }
8257
8258         leaf = path->nodes[0];
8259         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8260                                      struct btrfs_extent_item);
8261         btrfs_set_extent_refs(leaf, extent_item, 1);
8262         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8263         btrfs_set_extent_flags(leaf, extent_item,
8264                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8265
8266         if (skinny_metadata) {
8267                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8268                 num_bytes = fs_info->nodesize;
8269         } else {
8270                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8271                 btrfs_set_tree_block_key(leaf, block_info, key);
8272                 btrfs_set_tree_block_level(leaf, block_info, level);
8273                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8274         }
8275
8276         if (parent > 0) {
8277                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8278                 btrfs_set_extent_inline_ref_type(leaf, iref,
8279                                                  BTRFS_SHARED_BLOCK_REF_KEY);
8280                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8281         } else {
8282                 btrfs_set_extent_inline_ref_type(leaf, iref,
8283                                                  BTRFS_TREE_BLOCK_REF_KEY);
8284                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
8285         }
8286
8287         btrfs_mark_buffer_dirty(leaf);
8288         btrfs_free_path(path);
8289
8290         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8291                                           num_bytes);
8292         if (ret)
8293                 return ret;
8294
8295         ret = update_block_group(trans, fs_info, ins->objectid,
8296                                  fs_info->nodesize, 1);
8297         if (ret) { /* -ENOENT, logic error */
8298                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8299                         ins->objectid, ins->offset);
8300                 BUG();
8301         }
8302
8303         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid,
8304                                           fs_info->nodesize);
8305         return ret;
8306 }
8307
8308 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8309                                      u64 root_objectid, u64 owner,
8310                                      u64 offset, u64 ram_bytes,
8311                                      struct btrfs_key *ins)
8312 {
8313         struct btrfs_fs_info *fs_info = trans->fs_info;
8314         int ret;
8315
8316         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
8317
8318         ret = btrfs_add_delayed_data_ref(fs_info, trans, ins->objectid,
8319                                          ins->offset, 0, root_objectid, owner,
8320                                          offset, ram_bytes,
8321                                          BTRFS_ADD_DELAYED_EXTENT, NULL, NULL);
8322         return ret;
8323 }
8324
8325 /*
8326  * this is used by the tree logging recovery code.  It records that
8327  * an extent has been allocated and makes sure to clear the free
8328  * space cache bits as well
8329  */
8330 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8331                                    struct btrfs_fs_info *fs_info,
8332                                    u64 root_objectid, u64 owner, u64 offset,
8333                                    struct btrfs_key *ins)
8334 {
8335         int ret;
8336         struct btrfs_block_group_cache *block_group;
8337         struct btrfs_space_info *space_info;
8338
8339         /*
8340          * Mixed block groups will exclude before processing the log so we only
8341          * need to do the exclude dance if this fs isn't mixed.
8342          */
8343         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
8344                 ret = __exclude_logged_extent(fs_info, ins->objectid,
8345                                               ins->offset);
8346                 if (ret)
8347                         return ret;
8348         }
8349
8350         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
8351         if (!block_group)
8352                 return -EINVAL;
8353
8354         space_info = block_group->space_info;
8355         spin_lock(&space_info->lock);
8356         spin_lock(&block_group->lock);
8357         space_info->bytes_reserved += ins->offset;
8358         block_group->reserved += ins->offset;
8359         spin_unlock(&block_group->lock);
8360         spin_unlock(&space_info->lock);
8361
8362         ret = alloc_reserved_file_extent(trans, fs_info, 0, root_objectid,
8363                                          0, owner, offset, ins, 1);
8364         btrfs_put_block_group(block_group);
8365         return ret;
8366 }
8367
8368 static struct extent_buffer *
8369 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8370                       u64 bytenr, int level)
8371 {
8372         struct btrfs_fs_info *fs_info = root->fs_info;
8373         struct extent_buffer *buf;
8374
8375         buf = btrfs_find_create_tree_block(fs_info, bytenr);
8376         if (IS_ERR(buf))
8377                 return buf;
8378
8379         btrfs_set_header_generation(buf, trans->transid);
8380         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8381         btrfs_tree_lock(buf);
8382         clean_tree_block(fs_info, buf);
8383         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8384
8385         btrfs_set_lock_blocking(buf);
8386         set_extent_buffer_uptodate(buf);
8387
8388         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8389                 buf->log_index = root->log_transid % 2;
8390                 /*
8391                  * we allow two log transactions at a time, use different
8392                  * EXENT bit to differentiate dirty pages.
8393                  */
8394                 if (buf->log_index == 0)
8395                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8396                                         buf->start + buf->len - 1, GFP_NOFS);
8397                 else
8398                         set_extent_new(&root->dirty_log_pages, buf->start,
8399                                         buf->start + buf->len - 1);
8400         } else {
8401                 buf->log_index = -1;
8402                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8403                          buf->start + buf->len - 1, GFP_NOFS);
8404         }
8405         trans->dirty = true;
8406         /* this returns a buffer locked for blocking */
8407         return buf;
8408 }
8409
8410 static struct btrfs_block_rsv *
8411 use_block_rsv(struct btrfs_trans_handle *trans,
8412               struct btrfs_root *root, u32 blocksize)
8413 {
8414         struct btrfs_fs_info *fs_info = root->fs_info;
8415         struct btrfs_block_rsv *block_rsv;
8416         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
8417         int ret;
8418         bool global_updated = false;
8419
8420         block_rsv = get_block_rsv(trans, root);
8421
8422         if (unlikely(block_rsv->size == 0))
8423                 goto try_reserve;
8424 again:
8425         ret = block_rsv_use_bytes(block_rsv, blocksize);
8426         if (!ret)
8427                 return block_rsv;
8428
8429         if (block_rsv->failfast)
8430                 return ERR_PTR(ret);
8431
8432         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8433                 global_updated = true;
8434                 update_global_block_rsv(fs_info);
8435                 goto again;
8436         }
8437
8438         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8439                 static DEFINE_RATELIMIT_STATE(_rs,
8440                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8441                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8442                 if (__ratelimit(&_rs))
8443                         WARN(1, KERN_DEBUG
8444                                 "BTRFS: block rsv returned %d\n", ret);
8445         }
8446 try_reserve:
8447         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8448                                      BTRFS_RESERVE_NO_FLUSH);
8449         if (!ret)
8450                 return block_rsv;
8451         /*
8452          * If we couldn't reserve metadata bytes try and use some from
8453          * the global reserve if its space type is the same as the global
8454          * reservation.
8455          */
8456         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8457             block_rsv->space_info == global_rsv->space_info) {
8458                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8459                 if (!ret)
8460                         return global_rsv;
8461         }
8462         return ERR_PTR(ret);
8463 }
8464
8465 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8466                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8467 {
8468         block_rsv_add_bytes(block_rsv, blocksize, 0);
8469         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8470 }
8471
8472 /*
8473  * finds a free extent and does all the dirty work required for allocation
8474  * returns the tree buffer or an ERR_PTR on error.
8475  */
8476 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8477                                              struct btrfs_root *root,
8478                                              u64 parent, u64 root_objectid,
8479                                              const struct btrfs_disk_key *key,
8480                                              int level, u64 hint,
8481                                              u64 empty_size)
8482 {
8483         struct btrfs_fs_info *fs_info = root->fs_info;
8484         struct btrfs_key ins;
8485         struct btrfs_block_rsv *block_rsv;
8486         struct extent_buffer *buf;
8487         struct btrfs_delayed_extent_op *extent_op;
8488         u64 flags = 0;
8489         int ret;
8490         u32 blocksize = fs_info->nodesize;
8491         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8492
8493 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8494         if (btrfs_is_testing(fs_info)) {
8495                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8496                                             level);
8497                 if (!IS_ERR(buf))
8498                         root->alloc_bytenr += blocksize;
8499                 return buf;
8500         }
8501 #endif
8502
8503         block_rsv = use_block_rsv(trans, root, blocksize);
8504         if (IS_ERR(block_rsv))
8505                 return ERR_CAST(block_rsv);
8506
8507         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8508                                    empty_size, hint, &ins, 0, 0);
8509         if (ret)
8510                 goto out_unuse;
8511
8512         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8513         if (IS_ERR(buf)) {
8514                 ret = PTR_ERR(buf);
8515                 goto out_free_reserved;
8516         }
8517
8518         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8519                 if (parent == 0)
8520                         parent = ins.objectid;
8521                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8522         } else
8523                 BUG_ON(parent > 0);
8524
8525         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8526                 extent_op = btrfs_alloc_delayed_extent_op();
8527                 if (!extent_op) {
8528                         ret = -ENOMEM;
8529                         goto out_free_buf;
8530                 }
8531                 if (key)
8532                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8533                 else
8534                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8535                 extent_op->flags_to_set = flags;
8536                 extent_op->update_key = skinny_metadata ? false : true;
8537                 extent_op->update_flags = true;
8538                 extent_op->is_data = false;
8539                 extent_op->level = level;
8540
8541                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, ins.objectid,
8542                                                  ins.offset, parent,
8543                                                  root_objectid, level,
8544                                                  BTRFS_ADD_DELAYED_EXTENT,
8545                                                  extent_op, NULL, NULL);
8546                 if (ret)
8547                         goto out_free_delayed;
8548         }
8549         return buf;
8550
8551 out_free_delayed:
8552         btrfs_free_delayed_extent_op(extent_op);
8553 out_free_buf:
8554         free_extent_buffer(buf);
8555 out_free_reserved:
8556         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
8557 out_unuse:
8558         unuse_block_rsv(fs_info, block_rsv, blocksize);
8559         return ERR_PTR(ret);
8560 }
8561
8562 struct walk_control {
8563         u64 refs[BTRFS_MAX_LEVEL];
8564         u64 flags[BTRFS_MAX_LEVEL];
8565         struct btrfs_key update_progress;
8566         int stage;
8567         int level;
8568         int shared_level;
8569         int update_ref;
8570         int keep_locks;
8571         int reada_slot;
8572         int reada_count;
8573         int for_reloc;
8574 };
8575
8576 #define DROP_REFERENCE  1
8577 #define UPDATE_BACKREF  2
8578
8579 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8580                                      struct btrfs_root *root,
8581                                      struct walk_control *wc,
8582                                      struct btrfs_path *path)
8583 {
8584         struct btrfs_fs_info *fs_info = root->fs_info;
8585         u64 bytenr;
8586         u64 generation;
8587         u64 refs;
8588         u64 flags;
8589         u32 nritems;
8590         struct btrfs_key key;
8591         struct extent_buffer *eb;
8592         int ret;
8593         int slot;
8594         int nread = 0;
8595
8596         if (path->slots[wc->level] < wc->reada_slot) {
8597                 wc->reada_count = wc->reada_count * 2 / 3;
8598                 wc->reada_count = max(wc->reada_count, 2);
8599         } else {
8600                 wc->reada_count = wc->reada_count * 3 / 2;
8601                 wc->reada_count = min_t(int, wc->reada_count,
8602                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
8603         }
8604
8605         eb = path->nodes[wc->level];
8606         nritems = btrfs_header_nritems(eb);
8607
8608         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8609                 if (nread >= wc->reada_count)
8610                         break;
8611
8612                 cond_resched();
8613                 bytenr = btrfs_node_blockptr(eb, slot);
8614                 generation = btrfs_node_ptr_generation(eb, slot);
8615
8616                 if (slot == path->slots[wc->level])
8617                         goto reada;
8618
8619                 if (wc->stage == UPDATE_BACKREF &&
8620                     generation <= root->root_key.offset)
8621                         continue;
8622
8623                 /* We don't lock the tree block, it's OK to be racy here */
8624                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
8625                                                wc->level - 1, 1, &refs,
8626                                                &flags);
8627                 /* We don't care about errors in readahead. */
8628                 if (ret < 0)
8629                         continue;
8630                 BUG_ON(refs == 0);
8631
8632                 if (wc->stage == DROP_REFERENCE) {
8633                         if (refs == 1)
8634                                 goto reada;
8635
8636                         if (wc->level == 1 &&
8637                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8638                                 continue;
8639                         if (!wc->update_ref ||
8640                             generation <= root->root_key.offset)
8641                                 continue;
8642                         btrfs_node_key_to_cpu(eb, &key, slot);
8643                         ret = btrfs_comp_cpu_keys(&key,
8644                                                   &wc->update_progress);
8645                         if (ret < 0)
8646                                 continue;
8647                 } else {
8648                         if (wc->level == 1 &&
8649                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8650                                 continue;
8651                 }
8652 reada:
8653                 readahead_tree_block(fs_info, bytenr);
8654                 nread++;
8655         }
8656         wc->reada_slot = slot;
8657 }
8658
8659 /*
8660  * helper to process tree block while walking down the tree.
8661  *
8662  * when wc->stage == UPDATE_BACKREF, this function updates
8663  * back refs for pointers in the block.
8664  *
8665  * NOTE: return value 1 means we should stop walking down.
8666  */
8667 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8668                                    struct btrfs_root *root,
8669                                    struct btrfs_path *path,
8670                                    struct walk_control *wc, int lookup_info)
8671 {
8672         struct btrfs_fs_info *fs_info = root->fs_info;
8673         int level = wc->level;
8674         struct extent_buffer *eb = path->nodes[level];
8675         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8676         int ret;
8677
8678         if (wc->stage == UPDATE_BACKREF &&
8679             btrfs_header_owner(eb) != root->root_key.objectid)
8680                 return 1;
8681
8682         /*
8683          * when reference count of tree block is 1, it won't increase
8684          * again. once full backref flag is set, we never clear it.
8685          */
8686         if (lookup_info &&
8687             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8688              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8689                 BUG_ON(!path->locks[level]);
8690                 ret = btrfs_lookup_extent_info(trans, fs_info,
8691                                                eb->start, level, 1,
8692                                                &wc->refs[level],
8693                                                &wc->flags[level]);
8694                 BUG_ON(ret == -ENOMEM);
8695                 if (ret)
8696                         return ret;
8697                 BUG_ON(wc->refs[level] == 0);
8698         }
8699
8700         if (wc->stage == DROP_REFERENCE) {
8701                 if (wc->refs[level] > 1)
8702                         return 1;
8703
8704                 if (path->locks[level] && !wc->keep_locks) {
8705                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8706                         path->locks[level] = 0;
8707                 }
8708                 return 0;
8709         }
8710
8711         /* wc->stage == UPDATE_BACKREF */
8712         if (!(wc->flags[level] & flag)) {
8713                 BUG_ON(!path->locks[level]);
8714                 ret = btrfs_inc_ref(trans, root, eb, 1);
8715                 BUG_ON(ret); /* -ENOMEM */
8716                 ret = btrfs_dec_ref(trans, root, eb, 0);
8717                 BUG_ON(ret); /* -ENOMEM */
8718                 ret = btrfs_set_disk_extent_flags(trans, fs_info, eb->start,
8719                                                   eb->len, flag,
8720                                                   btrfs_header_level(eb), 0);
8721                 BUG_ON(ret); /* -ENOMEM */
8722                 wc->flags[level] |= flag;
8723         }
8724
8725         /*
8726          * the block is shared by multiple trees, so it's not good to
8727          * keep the tree lock
8728          */
8729         if (path->locks[level] && level > 0) {
8730                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8731                 path->locks[level] = 0;
8732         }
8733         return 0;
8734 }
8735
8736 /*
8737  * helper to process tree block pointer.
8738  *
8739  * when wc->stage == DROP_REFERENCE, this function checks
8740  * reference count of the block pointed to. if the block
8741  * is shared and we need update back refs for the subtree
8742  * rooted at the block, this function changes wc->stage to
8743  * UPDATE_BACKREF. if the block is shared and there is no
8744  * need to update back, this function drops the reference
8745  * to the block.
8746  *
8747  * NOTE: return value 1 means we should stop walking down.
8748  */
8749 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8750                                  struct btrfs_root *root,
8751                                  struct btrfs_path *path,
8752                                  struct walk_control *wc, int *lookup_info)
8753 {
8754         struct btrfs_fs_info *fs_info = root->fs_info;
8755         u64 bytenr;
8756         u64 generation;
8757         u64 parent;
8758         u32 blocksize;
8759         struct btrfs_key key;
8760         struct extent_buffer *next;
8761         int level = wc->level;
8762         int reada = 0;
8763         int ret = 0;
8764         bool need_account = false;
8765
8766         generation = btrfs_node_ptr_generation(path->nodes[level],
8767                                                path->slots[level]);
8768         /*
8769          * if the lower level block was created before the snapshot
8770          * was created, we know there is no need to update back refs
8771          * for the subtree
8772          */
8773         if (wc->stage == UPDATE_BACKREF &&
8774             generation <= root->root_key.offset) {
8775                 *lookup_info = 1;
8776                 return 1;
8777         }
8778
8779         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8780         blocksize = fs_info->nodesize;
8781
8782         next = find_extent_buffer(fs_info, bytenr);
8783         if (!next) {
8784                 next = btrfs_find_create_tree_block(fs_info, bytenr);
8785                 if (IS_ERR(next))
8786                         return PTR_ERR(next);
8787
8788                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8789                                                level - 1);
8790                 reada = 1;
8791         }
8792         btrfs_tree_lock(next);
8793         btrfs_set_lock_blocking(next);
8794
8795         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
8796                                        &wc->refs[level - 1],
8797                                        &wc->flags[level - 1]);
8798         if (ret < 0)
8799                 goto out_unlock;
8800
8801         if (unlikely(wc->refs[level - 1] == 0)) {
8802                 btrfs_err(fs_info, "Missing references.");
8803                 ret = -EIO;
8804                 goto out_unlock;
8805         }
8806         *lookup_info = 0;
8807
8808         if (wc->stage == DROP_REFERENCE) {
8809                 if (wc->refs[level - 1] > 1) {
8810                         need_account = true;
8811                         if (level == 1 &&
8812                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8813                                 goto skip;
8814
8815                         if (!wc->update_ref ||
8816                             generation <= root->root_key.offset)
8817                                 goto skip;
8818
8819                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8820                                               path->slots[level]);
8821                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8822                         if (ret < 0)
8823                                 goto skip;
8824
8825                         wc->stage = UPDATE_BACKREF;
8826                         wc->shared_level = level - 1;
8827                 }
8828         } else {
8829                 if (level == 1 &&
8830                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8831                         goto skip;
8832         }
8833
8834         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8835                 btrfs_tree_unlock(next);
8836                 free_extent_buffer(next);
8837                 next = NULL;
8838                 *lookup_info = 1;
8839         }
8840
8841         if (!next) {
8842                 if (reada && level == 1)
8843                         reada_walk_down(trans, root, wc, path);
8844                 next = read_tree_block(fs_info, bytenr, generation);
8845                 if (IS_ERR(next)) {
8846                         return PTR_ERR(next);
8847                 } else if (!extent_buffer_uptodate(next)) {
8848                         free_extent_buffer(next);
8849                         return -EIO;
8850                 }
8851                 btrfs_tree_lock(next);
8852                 btrfs_set_lock_blocking(next);
8853         }
8854
8855         level--;
8856         ASSERT(level == btrfs_header_level(next));
8857         if (level != btrfs_header_level(next)) {
8858                 btrfs_err(root->fs_info, "mismatched level");
8859                 ret = -EIO;
8860                 goto out_unlock;
8861         }
8862         path->nodes[level] = next;
8863         path->slots[level] = 0;
8864         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8865         wc->level = level;
8866         if (wc->level == 1)
8867                 wc->reada_slot = 0;
8868         return 0;
8869 skip:
8870         wc->refs[level - 1] = 0;
8871         wc->flags[level - 1] = 0;
8872         if (wc->stage == DROP_REFERENCE) {
8873                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8874                         parent = path->nodes[level]->start;
8875                 } else {
8876                         ASSERT(root->root_key.objectid ==
8877                                btrfs_header_owner(path->nodes[level]));
8878                         if (root->root_key.objectid !=
8879                             btrfs_header_owner(path->nodes[level])) {
8880                                 btrfs_err(root->fs_info,
8881                                                 "mismatched block owner");
8882                                 ret = -EIO;
8883                                 goto out_unlock;
8884                         }
8885                         parent = 0;
8886                 }
8887
8888                 if (need_account) {
8889                         ret = btrfs_qgroup_trace_subtree(trans, root, next,
8890                                                          generation, level - 1);
8891                         if (ret) {
8892                                 btrfs_err_rl(fs_info,
8893                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8894                                              ret);
8895                         }
8896                 }
8897                 ret = btrfs_free_extent(trans, fs_info, bytenr, blocksize,
8898                                         parent, root->root_key.objectid,
8899                                         level - 1, 0);
8900                 if (ret)
8901                         goto out_unlock;
8902         }
8903
8904         *lookup_info = 1;
8905         ret = 1;
8906
8907 out_unlock:
8908         btrfs_tree_unlock(next);
8909         free_extent_buffer(next);
8910
8911         return ret;
8912 }
8913
8914 /*
8915  * helper to process tree block while walking up the tree.
8916  *
8917  * when wc->stage == DROP_REFERENCE, this function drops
8918  * reference count on the block.
8919  *
8920  * when wc->stage == UPDATE_BACKREF, this function changes
8921  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8922  * to UPDATE_BACKREF previously while processing the block.
8923  *
8924  * NOTE: return value 1 means we should stop walking up.
8925  */
8926 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8927                                  struct btrfs_root *root,
8928                                  struct btrfs_path *path,
8929                                  struct walk_control *wc)
8930 {
8931         struct btrfs_fs_info *fs_info = root->fs_info;
8932         int ret;
8933         int level = wc->level;
8934         struct extent_buffer *eb = path->nodes[level];
8935         u64 parent = 0;
8936
8937         if (wc->stage == UPDATE_BACKREF) {
8938                 BUG_ON(wc->shared_level < level);
8939                 if (level < wc->shared_level)
8940                         goto out;
8941
8942                 ret = find_next_key(path, level + 1, &wc->update_progress);
8943                 if (ret > 0)
8944                         wc->update_ref = 0;
8945
8946                 wc->stage = DROP_REFERENCE;
8947                 wc->shared_level = -1;
8948                 path->slots[level] = 0;
8949
8950                 /*
8951                  * check reference count again if the block isn't locked.
8952                  * we should start walking down the tree again if reference
8953                  * count is one.
8954                  */
8955                 if (!path->locks[level]) {
8956                         BUG_ON(level == 0);
8957                         btrfs_tree_lock(eb);
8958                         btrfs_set_lock_blocking(eb);
8959                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8960
8961                         ret = btrfs_lookup_extent_info(trans, fs_info,
8962                                                        eb->start, level, 1,
8963                                                        &wc->refs[level],
8964                                                        &wc->flags[level]);
8965                         if (ret < 0) {
8966                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8967                                 path->locks[level] = 0;
8968                                 return ret;
8969                         }
8970                         BUG_ON(wc->refs[level] == 0);
8971                         if (wc->refs[level] == 1) {
8972                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8973                                 path->locks[level] = 0;
8974                                 return 1;
8975                         }
8976                 }
8977         }
8978
8979         /* wc->stage == DROP_REFERENCE */
8980         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8981
8982         if (wc->refs[level] == 1) {
8983                 if (level == 0) {
8984                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8985                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8986                         else
8987                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8988                         BUG_ON(ret); /* -ENOMEM */
8989                         ret = btrfs_qgroup_trace_leaf_items(trans, fs_info, eb);
8990                         if (ret) {
8991                                 btrfs_err_rl(fs_info,
8992                                              "error %d accounting leaf items. Quota is out of sync, rescan required.",
8993                                              ret);
8994                         }
8995                 }
8996                 /* make block locked assertion in clean_tree_block happy */
8997                 if (!path->locks[level] &&
8998                     btrfs_header_generation(eb) == trans->transid) {
8999                         btrfs_tree_lock(eb);
9000                         btrfs_set_lock_blocking(eb);
9001                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9002                 }
9003                 clean_tree_block(fs_info, eb);
9004         }
9005
9006         if (eb == root->node) {
9007                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9008                         parent = eb->start;
9009                 else
9010                         BUG_ON(root->root_key.objectid !=
9011                                btrfs_header_owner(eb));
9012         } else {
9013                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9014                         parent = path->nodes[level + 1]->start;
9015                 else
9016                         BUG_ON(root->root_key.objectid !=
9017                                btrfs_header_owner(path->nodes[level + 1]));
9018         }
9019
9020         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
9021 out:
9022         wc->refs[level] = 0;
9023         wc->flags[level] = 0;
9024         return 0;
9025 }
9026
9027 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
9028                                    struct btrfs_root *root,
9029                                    struct btrfs_path *path,
9030                                    struct walk_control *wc)
9031 {
9032         int level = wc->level;
9033         int lookup_info = 1;
9034         int ret;
9035
9036         while (level >= 0) {
9037                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
9038                 if (ret > 0)
9039                         break;
9040
9041                 if (level == 0)
9042                         break;
9043
9044                 if (path->slots[level] >=
9045                     btrfs_header_nritems(path->nodes[level]))
9046                         break;
9047
9048                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
9049                 if (ret > 0) {
9050                         path->slots[level]++;
9051                         continue;
9052                 } else if (ret < 0)
9053                         return ret;
9054                 level = wc->level;
9055         }
9056         return 0;
9057 }
9058
9059 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
9060                                  struct btrfs_root *root,
9061                                  struct btrfs_path *path,
9062                                  struct walk_control *wc, int max_level)
9063 {
9064         int level = wc->level;
9065         int ret;
9066
9067         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
9068         while (level < max_level && path->nodes[level]) {
9069                 wc->level = level;
9070                 if (path->slots[level] + 1 <
9071                     btrfs_header_nritems(path->nodes[level])) {
9072                         path->slots[level]++;
9073                         return 0;
9074                 } else {
9075                         ret = walk_up_proc(trans, root, path, wc);
9076                         if (ret > 0)
9077                                 return 0;
9078
9079                         if (path->locks[level]) {
9080                                 btrfs_tree_unlock_rw(path->nodes[level],
9081                                                      path->locks[level]);
9082                                 path->locks[level] = 0;
9083                         }
9084                         free_extent_buffer(path->nodes[level]);
9085                         path->nodes[level] = NULL;
9086                         level++;
9087                 }
9088         }
9089         return 1;
9090 }
9091
9092 /*
9093  * drop a subvolume tree.
9094  *
9095  * this function traverses the tree freeing any blocks that only
9096  * referenced by the tree.
9097  *
9098  * when a shared tree block is found. this function decreases its
9099  * reference count by one. if update_ref is true, this function
9100  * also make sure backrefs for the shared block and all lower level
9101  * blocks are properly updated.
9102  *
9103  * If called with for_reloc == 0, may exit early with -EAGAIN
9104  */
9105 int btrfs_drop_snapshot(struct btrfs_root *root,
9106                          struct btrfs_block_rsv *block_rsv, int update_ref,
9107                          int for_reloc)
9108 {
9109         struct btrfs_fs_info *fs_info = root->fs_info;
9110         struct btrfs_path *path;
9111         struct btrfs_trans_handle *trans;
9112         struct btrfs_root *tree_root = fs_info->tree_root;
9113         struct btrfs_root_item *root_item = &root->root_item;
9114         struct walk_control *wc;
9115         struct btrfs_key key;
9116         int err = 0;
9117         int ret;
9118         int level;
9119         bool root_dropped = false;
9120
9121         btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
9122
9123         path = btrfs_alloc_path();
9124         if (!path) {
9125                 err = -ENOMEM;
9126                 goto out;
9127         }
9128
9129         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9130         if (!wc) {
9131                 btrfs_free_path(path);
9132                 err = -ENOMEM;
9133                 goto out;
9134         }
9135
9136         trans = btrfs_start_transaction(tree_root, 0);
9137         if (IS_ERR(trans)) {
9138                 err = PTR_ERR(trans);
9139                 goto out_free;
9140         }
9141
9142         if (block_rsv)
9143                 trans->block_rsv = block_rsv;
9144
9145         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9146                 level = btrfs_header_level(root->node);
9147                 path->nodes[level] = btrfs_lock_root_node(root);
9148                 btrfs_set_lock_blocking(path->nodes[level]);
9149                 path->slots[level] = 0;
9150                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9151                 memset(&wc->update_progress, 0,
9152                        sizeof(wc->update_progress));
9153         } else {
9154                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9155                 memcpy(&wc->update_progress, &key,
9156                        sizeof(wc->update_progress));
9157
9158                 level = root_item->drop_level;
9159                 BUG_ON(level == 0);
9160                 path->lowest_level = level;
9161                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9162                 path->lowest_level = 0;
9163                 if (ret < 0) {
9164                         err = ret;
9165                         goto out_end_trans;
9166                 }
9167                 WARN_ON(ret > 0);
9168
9169                 /*
9170                  * unlock our path, this is safe because only this
9171                  * function is allowed to delete this snapshot
9172                  */
9173                 btrfs_unlock_up_safe(path, 0);
9174
9175                 level = btrfs_header_level(root->node);
9176                 while (1) {
9177                         btrfs_tree_lock(path->nodes[level]);
9178                         btrfs_set_lock_blocking(path->nodes[level]);
9179                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9180
9181                         ret = btrfs_lookup_extent_info(trans, fs_info,
9182                                                 path->nodes[level]->start,
9183                                                 level, 1, &wc->refs[level],
9184                                                 &wc->flags[level]);
9185                         if (ret < 0) {
9186                                 err = ret;
9187                                 goto out_end_trans;
9188                         }
9189                         BUG_ON(wc->refs[level] == 0);
9190
9191                         if (level == root_item->drop_level)
9192                                 break;
9193
9194                         btrfs_tree_unlock(path->nodes[level]);
9195                         path->locks[level] = 0;
9196                         WARN_ON(wc->refs[level] != 1);
9197                         level--;
9198                 }
9199         }
9200
9201         wc->level = level;
9202         wc->shared_level = -1;
9203         wc->stage = DROP_REFERENCE;
9204         wc->update_ref = update_ref;
9205         wc->keep_locks = 0;
9206         wc->for_reloc = for_reloc;
9207         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9208
9209         while (1) {
9210
9211                 ret = walk_down_tree(trans, root, path, wc);
9212                 if (ret < 0) {
9213                         err = ret;
9214                         break;
9215                 }
9216
9217                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9218                 if (ret < 0) {
9219                         err = ret;
9220                         break;
9221                 }
9222
9223                 if (ret > 0) {
9224                         BUG_ON(wc->stage != DROP_REFERENCE);
9225                         break;
9226                 }
9227
9228                 if (wc->stage == DROP_REFERENCE) {
9229                         level = wc->level;
9230                         btrfs_node_key(path->nodes[level],
9231                                        &root_item->drop_progress,
9232                                        path->slots[level]);
9233                         root_item->drop_level = level;
9234                 }
9235
9236                 BUG_ON(wc->level == 0);
9237                 if (btrfs_should_end_transaction(trans) ||
9238                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
9239                         ret = btrfs_update_root(trans, tree_root,
9240                                                 &root->root_key,
9241                                                 root_item);
9242                         if (ret) {
9243                                 btrfs_abort_transaction(trans, ret);
9244                                 err = ret;
9245                                 goto out_end_trans;
9246                         }
9247
9248                         btrfs_end_transaction_throttle(trans);
9249                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
9250                                 btrfs_debug(fs_info,
9251                                             "drop snapshot early exit");
9252                                 err = -EAGAIN;
9253                                 goto out_free;
9254                         }
9255
9256                         trans = btrfs_start_transaction(tree_root, 0);
9257                         if (IS_ERR(trans)) {
9258                                 err = PTR_ERR(trans);
9259                                 goto out_free;
9260                         }
9261                         if (block_rsv)
9262                                 trans->block_rsv = block_rsv;
9263                 }
9264         }
9265         btrfs_release_path(path);
9266         if (err)
9267                 goto out_end_trans;
9268
9269         ret = btrfs_del_root(trans, fs_info, &root->root_key);
9270         if (ret) {
9271                 btrfs_abort_transaction(trans, ret);
9272                 goto out_end_trans;
9273         }
9274
9275         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9276                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9277                                       NULL, NULL);
9278                 if (ret < 0) {
9279                         btrfs_abort_transaction(trans, ret);
9280                         err = ret;
9281                         goto out_end_trans;
9282                 } else if (ret > 0) {
9283                         /* if we fail to delete the orphan item this time
9284                          * around, it'll get picked up the next time.
9285                          *
9286                          * The most common failure here is just -ENOENT.
9287                          */
9288                         btrfs_del_orphan_item(trans, tree_root,
9289                                               root->root_key.objectid);
9290                 }
9291         }
9292
9293         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9294                 btrfs_add_dropped_root(trans, root);
9295         } else {
9296                 free_extent_buffer(root->node);
9297                 free_extent_buffer(root->commit_root);
9298                 btrfs_put_fs_root(root);
9299         }
9300         root_dropped = true;
9301 out_end_trans:
9302         btrfs_end_transaction_throttle(trans);
9303 out_free:
9304         kfree(wc);
9305         btrfs_free_path(path);
9306 out:
9307         /*
9308          * So if we need to stop dropping the snapshot for whatever reason we
9309          * need to make sure to add it back to the dead root list so that we
9310          * keep trying to do the work later.  This also cleans up roots if we
9311          * don't have it in the radix (like when we recover after a power fail
9312          * or unmount) so we don't leak memory.
9313          */
9314         if (!for_reloc && root_dropped == false)
9315                 btrfs_add_dead_root(root);
9316         if (err && err != -EAGAIN)
9317                 btrfs_handle_fs_error(fs_info, err, NULL);
9318         return err;
9319 }
9320
9321 /*
9322  * drop subtree rooted at tree block 'node'.
9323  *
9324  * NOTE: this function will unlock and release tree block 'node'
9325  * only used by relocation code
9326  */
9327 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9328                         struct btrfs_root *root,
9329                         struct extent_buffer *node,
9330                         struct extent_buffer *parent)
9331 {
9332         struct btrfs_fs_info *fs_info = root->fs_info;
9333         struct btrfs_path *path;
9334         struct walk_control *wc;
9335         int level;
9336         int parent_level;
9337         int ret = 0;
9338         int wret;
9339
9340         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9341
9342         path = btrfs_alloc_path();
9343         if (!path)
9344                 return -ENOMEM;
9345
9346         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9347         if (!wc) {
9348                 btrfs_free_path(path);
9349                 return -ENOMEM;
9350         }
9351
9352         btrfs_assert_tree_locked(parent);
9353         parent_level = btrfs_header_level(parent);
9354         extent_buffer_get(parent);
9355         path->nodes[parent_level] = parent;
9356         path->slots[parent_level] = btrfs_header_nritems(parent);
9357
9358         btrfs_assert_tree_locked(node);
9359         level = btrfs_header_level(node);
9360         path->nodes[level] = node;
9361         path->slots[level] = 0;
9362         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9363
9364         wc->refs[parent_level] = 1;
9365         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9366         wc->level = level;
9367         wc->shared_level = -1;
9368         wc->stage = DROP_REFERENCE;
9369         wc->update_ref = 0;
9370         wc->keep_locks = 1;
9371         wc->for_reloc = 1;
9372         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9373
9374         while (1) {
9375                 wret = walk_down_tree(trans, root, path, wc);
9376                 if (wret < 0) {
9377                         ret = wret;
9378                         break;
9379                 }
9380
9381                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9382                 if (wret < 0)
9383                         ret = wret;
9384                 if (wret != 0)
9385                         break;
9386         }
9387
9388         kfree(wc);
9389         btrfs_free_path(path);
9390         return ret;
9391 }
9392
9393 static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
9394 {
9395         u64 num_devices;
9396         u64 stripped;
9397
9398         /*
9399          * if restripe for this chunk_type is on pick target profile and
9400          * return, otherwise do the usual balance
9401          */
9402         stripped = get_restripe_target(fs_info, flags);
9403         if (stripped)
9404                 return extended_to_chunk(stripped);
9405
9406         num_devices = fs_info->fs_devices->rw_devices;
9407
9408         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9409                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9410                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9411
9412         if (num_devices == 1) {
9413                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9414                 stripped = flags & ~stripped;
9415
9416                 /* turn raid0 into single device chunks */
9417                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9418                         return stripped;
9419
9420                 /* turn mirroring into duplication */
9421                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9422                              BTRFS_BLOCK_GROUP_RAID10))
9423                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9424         } else {
9425                 /* they already had raid on here, just return */
9426                 if (flags & stripped)
9427                         return flags;
9428
9429                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9430                 stripped = flags & ~stripped;
9431
9432                 /* switch duplicated blocks with raid1 */
9433                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9434                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9435
9436                 /* this is drive concat, leave it alone */
9437         }
9438
9439         return flags;
9440 }
9441
9442 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9443 {
9444         struct btrfs_space_info *sinfo = cache->space_info;
9445         u64 num_bytes;
9446         u64 min_allocable_bytes;
9447         int ret = -ENOSPC;
9448
9449         /*
9450          * We need some metadata space and system metadata space for
9451          * allocating chunks in some corner cases until we force to set
9452          * it to be readonly.
9453          */
9454         if ((sinfo->flags &
9455              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9456             !force)
9457                 min_allocable_bytes = SZ_1M;
9458         else
9459                 min_allocable_bytes = 0;
9460
9461         spin_lock(&sinfo->lock);
9462         spin_lock(&cache->lock);
9463
9464         if (cache->ro) {
9465                 cache->ro++;
9466                 ret = 0;
9467                 goto out;
9468         }
9469
9470         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9471                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9472
9473         if (btrfs_space_info_used(sinfo, true) + num_bytes +
9474             min_allocable_bytes <= sinfo->total_bytes) {
9475                 sinfo->bytes_readonly += num_bytes;
9476                 cache->ro++;
9477                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9478                 ret = 0;
9479         }
9480 out:
9481         spin_unlock(&cache->lock);
9482         spin_unlock(&sinfo->lock);
9483         return ret;
9484 }
9485
9486 int btrfs_inc_block_group_ro(struct btrfs_fs_info *fs_info,
9487                              struct btrfs_block_group_cache *cache)
9488
9489 {
9490         struct btrfs_trans_handle *trans;
9491         u64 alloc_flags;
9492         int ret;
9493
9494 again:
9495         trans = btrfs_join_transaction(fs_info->extent_root);
9496         if (IS_ERR(trans))
9497                 return PTR_ERR(trans);
9498
9499         /*
9500          * we're not allowed to set block groups readonly after the dirty
9501          * block groups cache has started writing.  If it already started,
9502          * back off and let this transaction commit
9503          */
9504         mutex_lock(&fs_info->ro_block_group_mutex);
9505         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9506                 u64 transid = trans->transid;
9507
9508                 mutex_unlock(&fs_info->ro_block_group_mutex);
9509                 btrfs_end_transaction(trans);
9510
9511                 ret = btrfs_wait_for_commit(fs_info, transid);
9512                 if (ret)
9513                         return ret;
9514                 goto again;
9515         }
9516
9517         /*
9518          * if we are changing raid levels, try to allocate a corresponding
9519          * block group with the new raid level.
9520          */
9521         alloc_flags = update_block_group_flags(fs_info, cache->flags);
9522         if (alloc_flags != cache->flags) {
9523                 ret = do_chunk_alloc(trans, fs_info, alloc_flags,
9524                                      CHUNK_ALLOC_FORCE);
9525                 /*
9526                  * ENOSPC is allowed here, we may have enough space
9527                  * already allocated at the new raid level to
9528                  * carry on
9529                  */
9530                 if (ret == -ENOSPC)
9531                         ret = 0;
9532                 if (ret < 0)
9533                         goto out;
9534         }
9535
9536         ret = inc_block_group_ro(cache, 0);
9537         if (!ret)
9538                 goto out;
9539         alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
9540         ret = do_chunk_alloc(trans, fs_info, alloc_flags,
9541                              CHUNK_ALLOC_FORCE);
9542         if (ret < 0)
9543                 goto out;
9544         ret = inc_block_group_ro(cache, 0);
9545 out:
9546         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9547                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
9548                 mutex_lock(&fs_info->chunk_mutex);
9549                 check_system_chunk(trans, fs_info, alloc_flags);
9550                 mutex_unlock(&fs_info->chunk_mutex);
9551         }
9552         mutex_unlock(&fs_info->ro_block_group_mutex);
9553
9554         btrfs_end_transaction(trans);
9555         return ret;
9556 }
9557
9558 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9559                             struct btrfs_fs_info *fs_info, u64 type)
9560 {
9561         u64 alloc_flags = get_alloc_profile(fs_info, type);
9562
9563         return do_chunk_alloc(trans, fs_info, alloc_flags, CHUNK_ALLOC_FORCE);
9564 }
9565
9566 /*
9567  * helper to account the unused space of all the readonly block group in the
9568  * space_info. takes mirrors into account.
9569  */
9570 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9571 {
9572         struct btrfs_block_group_cache *block_group;
9573         u64 free_bytes = 0;
9574         int factor;
9575
9576         /* It's df, we don't care if it's racy */
9577         if (list_empty(&sinfo->ro_bgs))
9578                 return 0;
9579
9580         spin_lock(&sinfo->lock);
9581         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9582                 spin_lock(&block_group->lock);
9583
9584                 if (!block_group->ro) {
9585                         spin_unlock(&block_group->lock);
9586                         continue;
9587                 }
9588
9589                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9590                                           BTRFS_BLOCK_GROUP_RAID10 |
9591                                           BTRFS_BLOCK_GROUP_DUP))
9592                         factor = 2;
9593                 else
9594                         factor = 1;
9595
9596                 free_bytes += (block_group->key.offset -
9597                                btrfs_block_group_used(&block_group->item)) *
9598                                factor;
9599
9600                 spin_unlock(&block_group->lock);
9601         }
9602         spin_unlock(&sinfo->lock);
9603
9604         return free_bytes;
9605 }
9606
9607 void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
9608 {
9609         struct btrfs_space_info *sinfo = cache->space_info;
9610         u64 num_bytes;
9611
9612         BUG_ON(!cache->ro);
9613
9614         spin_lock(&sinfo->lock);
9615         spin_lock(&cache->lock);
9616         if (!--cache->ro) {
9617                 num_bytes = cache->key.offset - cache->reserved -
9618                             cache->pinned - cache->bytes_super -
9619                             btrfs_block_group_used(&cache->item);
9620                 sinfo->bytes_readonly -= num_bytes;
9621                 list_del_init(&cache->ro_list);
9622         }
9623         spin_unlock(&cache->lock);
9624         spin_unlock(&sinfo->lock);
9625 }
9626
9627 /*
9628  * checks to see if its even possible to relocate this block group.
9629  *
9630  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9631  * ok to go ahead and try.
9632  */
9633 int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)
9634 {
9635         struct btrfs_root *root = fs_info->extent_root;
9636         struct btrfs_block_group_cache *block_group;
9637         struct btrfs_space_info *space_info;
9638         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
9639         struct btrfs_device *device;
9640         struct btrfs_trans_handle *trans;
9641         u64 min_free;
9642         u64 dev_min = 1;
9643         u64 dev_nr = 0;
9644         u64 target;
9645         int debug;
9646         int index;
9647         int full = 0;
9648         int ret = 0;
9649
9650         debug = btrfs_test_opt(fs_info, ENOSPC_DEBUG);
9651
9652         block_group = btrfs_lookup_block_group(fs_info, bytenr);
9653
9654         /* odd, couldn't find the block group, leave it alone */
9655         if (!block_group) {
9656                 if (debug)
9657                         btrfs_warn(fs_info,
9658                                    "can't find block group for bytenr %llu",
9659                                    bytenr);
9660                 return -1;
9661         }
9662
9663         min_free = btrfs_block_group_used(&block_group->item);
9664
9665         /* no bytes used, we're good */
9666         if (!min_free)
9667                 goto out;
9668
9669         space_info = block_group->space_info;
9670         spin_lock(&space_info->lock);
9671
9672         full = space_info->full;
9673
9674         /*
9675          * if this is the last block group we have in this space, we can't
9676          * relocate it unless we're able to allocate a new chunk below.
9677          *
9678          * Otherwise, we need to make sure we have room in the space to handle
9679          * all of the extents from this block group.  If we can, we're good
9680          */
9681         if ((space_info->total_bytes != block_group->key.offset) &&
9682             (btrfs_space_info_used(space_info, false) + min_free <
9683              space_info->total_bytes)) {
9684                 spin_unlock(&space_info->lock);
9685                 goto out;
9686         }
9687         spin_unlock(&space_info->lock);
9688
9689         /*
9690          * ok we don't have enough space, but maybe we have free space on our
9691          * devices to allocate new chunks for relocation, so loop through our
9692          * alloc devices and guess if we have enough space.  if this block
9693          * group is going to be restriped, run checks against the target
9694          * profile instead of the current one.
9695          */
9696         ret = -1;
9697
9698         /*
9699          * index:
9700          *      0: raid10
9701          *      1: raid1
9702          *      2: dup
9703          *      3: raid0
9704          *      4: single
9705          */
9706         target = get_restripe_target(fs_info, block_group->flags);
9707         if (target) {
9708                 index = __get_raid_index(extended_to_chunk(target));
9709         } else {
9710                 /*
9711                  * this is just a balance, so if we were marked as full
9712                  * we know there is no space for a new chunk
9713                  */
9714                 if (full) {
9715                         if (debug)
9716                                 btrfs_warn(fs_info,
9717                                            "no space to alloc new chunk for block group %llu",
9718                                            block_group->key.objectid);
9719                         goto out;
9720                 }
9721
9722                 index = get_block_group_index(block_group);
9723         }
9724
9725         if (index == BTRFS_RAID_RAID10) {
9726                 dev_min = 4;
9727                 /* Divide by 2 */
9728                 min_free >>= 1;
9729         } else if (index == BTRFS_RAID_RAID1) {
9730                 dev_min = 2;
9731         } else if (index == BTRFS_RAID_DUP) {
9732                 /* Multiply by 2 */
9733                 min_free <<= 1;
9734         } else if (index == BTRFS_RAID_RAID0) {
9735                 dev_min = fs_devices->rw_devices;
9736                 min_free = div64_u64(min_free, dev_min);
9737         }
9738
9739         /* We need to do this so that we can look at pending chunks */
9740         trans = btrfs_join_transaction(root);
9741         if (IS_ERR(trans)) {
9742                 ret = PTR_ERR(trans);
9743                 goto out;
9744         }
9745
9746         mutex_lock(&fs_info->chunk_mutex);
9747         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9748                 u64 dev_offset;
9749
9750                 /*
9751                  * check to make sure we can actually find a chunk with enough
9752                  * space to fit our block group in.
9753                  */
9754                 if (device->total_bytes > device->bytes_used + min_free &&
9755                     !device->is_tgtdev_for_dev_replace) {
9756                         ret = find_free_dev_extent(trans, device, min_free,
9757                                                    &dev_offset, NULL);
9758                         if (!ret)
9759                                 dev_nr++;
9760
9761                         if (dev_nr >= dev_min)
9762                                 break;
9763
9764                         ret = -1;
9765                 }
9766         }
9767         if (debug && ret == -1)
9768                 btrfs_warn(fs_info,
9769                            "no space to allocate a new chunk for block group %llu",
9770                            block_group->key.objectid);
9771         mutex_unlock(&fs_info->chunk_mutex);
9772         btrfs_end_transaction(trans);
9773 out:
9774         btrfs_put_block_group(block_group);
9775         return ret;
9776 }
9777
9778 static int find_first_block_group(struct btrfs_fs_info *fs_info,
9779                                   struct btrfs_path *path,
9780                                   struct btrfs_key *key)
9781 {
9782         struct btrfs_root *root = fs_info->extent_root;
9783         int ret = 0;
9784         struct btrfs_key found_key;
9785         struct extent_buffer *leaf;
9786         int slot;
9787
9788         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9789         if (ret < 0)
9790                 goto out;
9791
9792         while (1) {
9793                 slot = path->slots[0];
9794                 leaf = path->nodes[0];
9795                 if (slot >= btrfs_header_nritems(leaf)) {
9796                         ret = btrfs_next_leaf(root, path);
9797                         if (ret == 0)
9798                                 continue;
9799                         if (ret < 0)
9800                                 goto out;
9801                         break;
9802                 }
9803                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9804
9805                 if (found_key.objectid >= key->objectid &&
9806                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9807                         struct extent_map_tree *em_tree;
9808                         struct extent_map *em;
9809
9810                         em_tree = &root->fs_info->mapping_tree.map_tree;
9811                         read_lock(&em_tree->lock);
9812                         em = lookup_extent_mapping(em_tree, found_key.objectid,
9813                                                    found_key.offset);
9814                         read_unlock(&em_tree->lock);
9815                         if (!em) {
9816                                 btrfs_err(fs_info,
9817                         "logical %llu len %llu found bg but no related chunk",
9818                                           found_key.objectid, found_key.offset);
9819                                 ret = -ENOENT;
9820                         } else {
9821                                 ret = 0;
9822                         }
9823                         free_extent_map(em);
9824                         goto out;
9825                 }
9826                 path->slots[0]++;
9827         }
9828 out:
9829         return ret;
9830 }
9831
9832 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9833 {
9834         struct btrfs_block_group_cache *block_group;
9835         u64 last = 0;
9836
9837         while (1) {
9838                 struct inode *inode;
9839
9840                 block_group = btrfs_lookup_first_block_group(info, last);
9841                 while (block_group) {
9842                         spin_lock(&block_group->lock);
9843                         if (block_group->iref)
9844                                 break;
9845                         spin_unlock(&block_group->lock);
9846                         block_group = next_block_group(info, block_group);
9847                 }
9848                 if (!block_group) {
9849                         if (last == 0)
9850                                 break;
9851                         last = 0;
9852                         continue;
9853                 }
9854
9855                 inode = block_group->inode;
9856                 block_group->iref = 0;
9857                 block_group->inode = NULL;
9858                 spin_unlock(&block_group->lock);
9859                 ASSERT(block_group->io_ctl.inode == NULL);
9860                 iput(inode);
9861                 last = block_group->key.objectid + block_group->key.offset;
9862                 btrfs_put_block_group(block_group);
9863         }
9864 }
9865
9866 /*
9867  * Must be called only after stopping all workers, since we could have block
9868  * group caching kthreads running, and therefore they could race with us if we
9869  * freed the block groups before stopping them.
9870  */
9871 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9872 {
9873         struct btrfs_block_group_cache *block_group;
9874         struct btrfs_space_info *space_info;
9875         struct btrfs_caching_control *caching_ctl;
9876         struct rb_node *n;
9877
9878         down_write(&info->commit_root_sem);
9879         while (!list_empty(&info->caching_block_groups)) {
9880                 caching_ctl = list_entry(info->caching_block_groups.next,
9881                                          struct btrfs_caching_control, list);
9882                 list_del(&caching_ctl->list);
9883                 put_caching_control(caching_ctl);
9884         }
9885         up_write(&info->commit_root_sem);
9886
9887         spin_lock(&info->unused_bgs_lock);
9888         while (!list_empty(&info->unused_bgs)) {
9889                 block_group = list_first_entry(&info->unused_bgs,
9890                                                struct btrfs_block_group_cache,
9891                                                bg_list);
9892                 list_del_init(&block_group->bg_list);
9893                 btrfs_put_block_group(block_group);
9894         }
9895         spin_unlock(&info->unused_bgs_lock);
9896
9897         spin_lock(&info->block_group_cache_lock);
9898         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9899                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9900                                        cache_node);
9901                 rb_erase(&block_group->cache_node,
9902                          &info->block_group_cache_tree);
9903                 RB_CLEAR_NODE(&block_group->cache_node);
9904                 spin_unlock(&info->block_group_cache_lock);
9905
9906                 down_write(&block_group->space_info->groups_sem);
9907                 list_del(&block_group->list);
9908                 up_write(&block_group->space_info->groups_sem);
9909
9910                 /*
9911                  * We haven't cached this block group, which means we could
9912                  * possibly have excluded extents on this block group.
9913                  */
9914                 if (block_group->cached == BTRFS_CACHE_NO ||
9915                     block_group->cached == BTRFS_CACHE_ERROR)
9916                         free_excluded_extents(info, block_group);
9917
9918                 btrfs_remove_free_space_cache(block_group);
9919                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
9920                 ASSERT(list_empty(&block_group->dirty_list));
9921                 ASSERT(list_empty(&block_group->io_list));
9922                 ASSERT(list_empty(&block_group->bg_list));
9923                 ASSERT(atomic_read(&block_group->count) == 1);
9924                 btrfs_put_block_group(block_group);
9925
9926                 spin_lock(&info->block_group_cache_lock);
9927         }
9928         spin_unlock(&info->block_group_cache_lock);
9929
9930         /* now that all the block groups are freed, go through and
9931          * free all the space_info structs.  This is only called during
9932          * the final stages of unmount, and so we know nobody is
9933          * using them.  We call synchronize_rcu() once before we start,
9934          * just to be on the safe side.
9935          */
9936         synchronize_rcu();
9937
9938         release_global_block_rsv(info);
9939
9940         while (!list_empty(&info->space_info)) {
9941                 int i;
9942
9943                 space_info = list_entry(info->space_info.next,
9944                                         struct btrfs_space_info,
9945                                         list);
9946
9947                 /*
9948                  * Do not hide this behind enospc_debug, this is actually
9949                  * important and indicates a real bug if this happens.
9950                  */
9951                 if (WARN_ON(space_info->bytes_pinned > 0 ||
9952                             space_info->bytes_reserved > 0 ||
9953                             space_info->bytes_may_use > 0))
9954                         dump_space_info(info, space_info, 0, 0);
9955                 list_del(&space_info->list);
9956                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9957                         struct kobject *kobj;
9958                         kobj = space_info->block_group_kobjs[i];
9959                         space_info->block_group_kobjs[i] = NULL;
9960                         if (kobj) {
9961                                 kobject_del(kobj);
9962                                 kobject_put(kobj);
9963                         }
9964                 }
9965                 kobject_del(&space_info->kobj);
9966                 kobject_put(&space_info->kobj);
9967         }
9968         return 0;
9969 }
9970
9971 static void __link_block_group(struct btrfs_space_info *space_info,
9972                                struct btrfs_block_group_cache *cache)
9973 {
9974         int index = get_block_group_index(cache);
9975         bool first = false;
9976
9977         down_write(&space_info->groups_sem);
9978         if (list_empty(&space_info->block_groups[index]))
9979                 first = true;
9980         list_add_tail(&cache->list, &space_info->block_groups[index]);
9981         up_write(&space_info->groups_sem);
9982
9983         if (first) {
9984                 struct raid_kobject *rkobj;
9985                 int ret;
9986
9987                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9988                 if (!rkobj)
9989                         goto out_err;
9990                 rkobj->raid_type = index;
9991                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9992                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9993                                   "%s", get_raid_name(index));
9994                 if (ret) {
9995                         kobject_put(&rkobj->kobj);
9996                         goto out_err;
9997                 }
9998                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9999         }
10000
10001         return;
10002 out_err:
10003         btrfs_warn(cache->fs_info,
10004                    "failed to add kobject for block cache, ignoring");
10005 }
10006
10007 static struct btrfs_block_group_cache *
10008 btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
10009                                u64 start, u64 size)
10010 {
10011         struct btrfs_block_group_cache *cache;
10012
10013         cache = kzalloc(sizeof(*cache), GFP_NOFS);
10014         if (!cache)
10015                 return NULL;
10016
10017         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
10018                                         GFP_NOFS);
10019         if (!cache->free_space_ctl) {
10020                 kfree(cache);
10021                 return NULL;
10022         }
10023
10024         cache->key.objectid = start;
10025         cache->key.offset = size;
10026         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10027
10028         cache->fs_info = fs_info;
10029         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
10030         set_free_space_tree_thresholds(cache);
10031
10032         atomic_set(&cache->count, 1);
10033         spin_lock_init(&cache->lock);
10034         init_rwsem(&cache->data_rwsem);
10035         INIT_LIST_HEAD(&cache->list);
10036         INIT_LIST_HEAD(&cache->cluster_list);
10037         INIT_LIST_HEAD(&cache->bg_list);
10038         INIT_LIST_HEAD(&cache->ro_list);
10039         INIT_LIST_HEAD(&cache->dirty_list);
10040         INIT_LIST_HEAD(&cache->io_list);
10041         btrfs_init_free_space_ctl(cache);
10042         atomic_set(&cache->trimming, 0);
10043         mutex_init(&cache->free_space_lock);
10044         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
10045
10046         return cache;
10047 }
10048
10049 int btrfs_read_block_groups(struct btrfs_fs_info *info)
10050 {
10051         struct btrfs_path *path;
10052         int ret;
10053         struct btrfs_block_group_cache *cache;
10054         struct btrfs_space_info *space_info;
10055         struct btrfs_key key;
10056         struct btrfs_key found_key;
10057         struct extent_buffer *leaf;
10058         int need_clear = 0;
10059         u64 cache_gen;
10060         u64 feature;
10061         int mixed;
10062
10063         feature = btrfs_super_incompat_flags(info->super_copy);
10064         mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
10065
10066         key.objectid = 0;
10067         key.offset = 0;
10068         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10069         path = btrfs_alloc_path();
10070         if (!path)
10071                 return -ENOMEM;
10072         path->reada = READA_FORWARD;
10073
10074         cache_gen = btrfs_super_cache_generation(info->super_copy);
10075         if (btrfs_test_opt(info, SPACE_CACHE) &&
10076             btrfs_super_generation(info->super_copy) != cache_gen)
10077                 need_clear = 1;
10078         if (btrfs_test_opt(info, CLEAR_CACHE))
10079                 need_clear = 1;
10080
10081         while (1) {
10082                 ret = find_first_block_group(info, path, &key);
10083                 if (ret > 0)
10084                         break;
10085                 if (ret != 0)
10086                         goto error;
10087
10088                 leaf = path->nodes[0];
10089                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10090
10091                 cache = btrfs_create_block_group_cache(info, found_key.objectid,
10092                                                        found_key.offset);
10093                 if (!cache) {
10094                         ret = -ENOMEM;
10095                         goto error;
10096                 }
10097
10098                 if (need_clear) {
10099                         /*
10100                          * When we mount with old space cache, we need to
10101                          * set BTRFS_DC_CLEAR and set dirty flag.
10102                          *
10103                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10104                          *    truncate the old free space cache inode and
10105                          *    setup a new one.
10106                          * b) Setting 'dirty flag' makes sure that we flush
10107                          *    the new space cache info onto disk.
10108                          */
10109                         if (btrfs_test_opt(info, SPACE_CACHE))
10110                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
10111                 }
10112
10113                 read_extent_buffer(leaf, &cache->item,
10114                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
10115                                    sizeof(cache->item));
10116                 cache->flags = btrfs_block_group_flags(&cache->item);
10117                 if (!mixed &&
10118                     ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
10119                     (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
10120                         btrfs_err(info,
10121 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
10122                                   cache->key.objectid);
10123                         ret = -EINVAL;
10124                         goto error;
10125                 }
10126
10127                 key.objectid = found_key.objectid + found_key.offset;
10128                 btrfs_release_path(path);
10129
10130                 /*
10131                  * We need to exclude the super stripes now so that the space
10132                  * info has super bytes accounted for, otherwise we'll think
10133                  * we have more space than we actually do.
10134                  */
10135                 ret = exclude_super_stripes(info, cache);
10136                 if (ret) {
10137                         /*
10138                          * We may have excluded something, so call this just in
10139                          * case.
10140                          */
10141                         free_excluded_extents(info, cache);
10142                         btrfs_put_block_group(cache);
10143                         goto error;
10144                 }
10145
10146                 /*
10147                  * check for two cases, either we are full, and therefore
10148                  * don't need to bother with the caching work since we won't
10149                  * find any space, or we are empty, and we can just add all
10150                  * the space in and be done with it.  This saves us _alot_ of
10151                  * time, particularly in the full case.
10152                  */
10153                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10154                         cache->last_byte_to_unpin = (u64)-1;
10155                         cache->cached = BTRFS_CACHE_FINISHED;
10156                         free_excluded_extents(info, cache);
10157                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10158                         cache->last_byte_to_unpin = (u64)-1;
10159                         cache->cached = BTRFS_CACHE_FINISHED;
10160                         add_new_free_space(cache, info,
10161                                            found_key.objectid,
10162                                            found_key.objectid +
10163                                            found_key.offset);
10164                         free_excluded_extents(info, cache);
10165                 }
10166
10167                 ret = btrfs_add_block_group_cache(info, cache);
10168                 if (ret) {
10169                         btrfs_remove_free_space_cache(cache);
10170                         btrfs_put_block_group(cache);
10171                         goto error;
10172                 }
10173
10174                 trace_btrfs_add_block_group(info, cache, 0);
10175                 update_space_info(info, cache->flags, found_key.offset,
10176                                   btrfs_block_group_used(&cache->item),
10177                                   cache->bytes_super, &space_info);
10178
10179                 cache->space_info = space_info;
10180
10181                 __link_block_group(space_info, cache);
10182
10183                 set_avail_alloc_bits(info, cache->flags);
10184                 if (btrfs_chunk_readonly(info, cache->key.objectid)) {
10185                         inc_block_group_ro(cache, 1);
10186                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10187                         spin_lock(&info->unused_bgs_lock);
10188                         /* Should always be true but just in case. */
10189                         if (list_empty(&cache->bg_list)) {
10190                                 btrfs_get_block_group(cache);
10191                                 list_add_tail(&cache->bg_list,
10192                                               &info->unused_bgs);
10193                         }
10194                         spin_unlock(&info->unused_bgs_lock);
10195                 }
10196         }
10197
10198         list_for_each_entry_rcu(space_info, &info->space_info, list) {
10199                 if (!(get_alloc_profile(info, space_info->flags) &
10200                       (BTRFS_BLOCK_GROUP_RAID10 |
10201                        BTRFS_BLOCK_GROUP_RAID1 |
10202                        BTRFS_BLOCK_GROUP_RAID5 |
10203                        BTRFS_BLOCK_GROUP_RAID6 |
10204                        BTRFS_BLOCK_GROUP_DUP)))
10205                         continue;
10206                 /*
10207                  * avoid allocating from un-mirrored block group if there are
10208                  * mirrored block groups.
10209                  */
10210                 list_for_each_entry(cache,
10211                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10212                                 list)
10213                         inc_block_group_ro(cache, 1);
10214                 list_for_each_entry(cache,
10215                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10216                                 list)
10217                         inc_block_group_ro(cache, 1);
10218         }
10219
10220         init_global_block_rsv(info);
10221         ret = 0;
10222 error:
10223         btrfs_free_path(path);
10224         return ret;
10225 }
10226
10227 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
10228                                        struct btrfs_fs_info *fs_info)
10229 {
10230         struct btrfs_block_group_cache *block_group, *tmp;
10231         struct btrfs_root *extent_root = fs_info->extent_root;
10232         struct btrfs_block_group_item item;
10233         struct btrfs_key key;
10234         int ret = 0;
10235         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10236
10237         trans->can_flush_pending_bgs = false;
10238         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10239                 if (ret)
10240                         goto next;
10241
10242                 spin_lock(&block_group->lock);
10243                 memcpy(&item, &block_group->item, sizeof(item));
10244                 memcpy(&key, &block_group->key, sizeof(key));
10245                 spin_unlock(&block_group->lock);
10246
10247                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10248                                         sizeof(item));
10249                 if (ret)
10250                         btrfs_abort_transaction(trans, ret);
10251                 ret = btrfs_finish_chunk_alloc(trans, fs_info, key.objectid,
10252                                                key.offset);
10253                 if (ret)
10254                         btrfs_abort_transaction(trans, ret);
10255                 add_block_group_free_space(trans, fs_info, block_group);
10256                 /* already aborted the transaction if it failed. */
10257 next:
10258                 list_del_init(&block_group->bg_list);
10259         }
10260         trans->can_flush_pending_bgs = can_flush_pending_bgs;
10261 }
10262
10263 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10264                            struct btrfs_fs_info *fs_info, u64 bytes_used,
10265                            u64 type, u64 chunk_offset, u64 size)
10266 {
10267         struct btrfs_block_group_cache *cache;
10268         int ret;
10269
10270         btrfs_set_log_full_commit(fs_info, trans);
10271
10272         cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
10273         if (!cache)
10274                 return -ENOMEM;
10275
10276         btrfs_set_block_group_used(&cache->item, bytes_used);
10277         btrfs_set_block_group_chunk_objectid(&cache->item,
10278                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID);
10279         btrfs_set_block_group_flags(&cache->item, type);
10280
10281         cache->flags = type;
10282         cache->last_byte_to_unpin = (u64)-1;
10283         cache->cached = BTRFS_CACHE_FINISHED;
10284         cache->needs_free_space = 1;
10285         ret = exclude_super_stripes(fs_info, cache);
10286         if (ret) {
10287                 /*
10288                  * We may have excluded something, so call this just in
10289                  * case.
10290                  */
10291                 free_excluded_extents(fs_info, cache);
10292                 btrfs_put_block_group(cache);
10293                 return ret;
10294         }
10295
10296         add_new_free_space(cache, fs_info, chunk_offset, chunk_offset + size);
10297
10298         free_excluded_extents(fs_info, cache);
10299
10300 #ifdef CONFIG_BTRFS_DEBUG
10301         if (btrfs_should_fragment_free_space(cache)) {
10302                 u64 new_bytes_used = size - bytes_used;
10303
10304                 bytes_used += new_bytes_used >> 1;
10305                 fragment_free_space(cache);
10306         }
10307 #endif
10308         /*
10309          * Ensure the corresponding space_info object is created and
10310          * assigned to our block group. We want our bg to be added to the rbtree
10311          * with its ->space_info set.
10312          */
10313         cache->space_info = __find_space_info(fs_info, cache->flags);
10314         if (!cache->space_info) {
10315                 ret = create_space_info(fs_info, cache->flags,
10316                                        &cache->space_info);
10317                 if (ret) {
10318                         btrfs_remove_free_space_cache(cache);
10319                         btrfs_put_block_group(cache);
10320                         return ret;
10321                 }
10322         }
10323
10324         ret = btrfs_add_block_group_cache(fs_info, cache);
10325         if (ret) {
10326                 btrfs_remove_free_space_cache(cache);
10327                 btrfs_put_block_group(cache);
10328                 return ret;
10329         }
10330
10331         /*
10332          * Now that our block group has its ->space_info set and is inserted in
10333          * the rbtree, update the space info's counters.
10334          */
10335         trace_btrfs_add_block_group(fs_info, cache, 1);
10336         update_space_info(fs_info, cache->flags, size, bytes_used,
10337                                 cache->bytes_super, &cache->space_info);
10338         update_global_block_rsv(fs_info);
10339
10340         __link_block_group(cache->space_info, cache);
10341
10342         list_add_tail(&cache->bg_list, &trans->new_bgs);
10343
10344         set_avail_alloc_bits(fs_info, type);
10345         return 0;
10346 }
10347
10348 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10349 {
10350         u64 extra_flags = chunk_to_extended(flags) &
10351                                 BTRFS_EXTENDED_PROFILE_MASK;
10352
10353         write_seqlock(&fs_info->profiles_lock);
10354         if (flags & BTRFS_BLOCK_GROUP_DATA)
10355                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10356         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10357                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10358         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10359                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10360         write_sequnlock(&fs_info->profiles_lock);
10361 }
10362
10363 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10364                              struct btrfs_fs_info *fs_info, u64 group_start,
10365                              struct extent_map *em)
10366 {
10367         struct btrfs_root *root = fs_info->extent_root;
10368         struct btrfs_path *path;
10369         struct btrfs_block_group_cache *block_group;
10370         struct btrfs_free_cluster *cluster;
10371         struct btrfs_root *tree_root = fs_info->tree_root;
10372         struct btrfs_key key;
10373         struct inode *inode;
10374         struct kobject *kobj = NULL;
10375         int ret;
10376         int index;
10377         int factor;
10378         struct btrfs_caching_control *caching_ctl = NULL;
10379         bool remove_em;
10380
10381         block_group = btrfs_lookup_block_group(fs_info, group_start);
10382         BUG_ON(!block_group);
10383         BUG_ON(!block_group->ro);
10384
10385         /*
10386          * Free the reserved super bytes from this block group before
10387          * remove it.
10388          */
10389         free_excluded_extents(fs_info, block_group);
10390
10391         memcpy(&key, &block_group->key, sizeof(key));
10392         index = get_block_group_index(block_group);
10393         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10394                                   BTRFS_BLOCK_GROUP_RAID1 |
10395                                   BTRFS_BLOCK_GROUP_RAID10))
10396                 factor = 2;
10397         else
10398                 factor = 1;
10399
10400         /* make sure this block group isn't part of an allocation cluster */
10401         cluster = &fs_info->data_alloc_cluster;
10402         spin_lock(&cluster->refill_lock);
10403         btrfs_return_cluster_to_free_space(block_group, cluster);
10404         spin_unlock(&cluster->refill_lock);
10405
10406         /*
10407          * make sure this block group isn't part of a metadata
10408          * allocation cluster
10409          */
10410         cluster = &fs_info->meta_alloc_cluster;
10411         spin_lock(&cluster->refill_lock);
10412         btrfs_return_cluster_to_free_space(block_group, cluster);
10413         spin_unlock(&cluster->refill_lock);
10414
10415         path = btrfs_alloc_path();
10416         if (!path) {
10417                 ret = -ENOMEM;
10418                 goto out;
10419         }
10420
10421         /*
10422          * get the inode first so any iput calls done for the io_list
10423          * aren't the final iput (no unlinks allowed now)
10424          */
10425         inode = lookup_free_space_inode(fs_info, block_group, path);
10426
10427         mutex_lock(&trans->transaction->cache_write_mutex);
10428         /*
10429          * make sure our free spache cache IO is done before remove the
10430          * free space inode
10431          */
10432         spin_lock(&trans->transaction->dirty_bgs_lock);
10433         if (!list_empty(&block_group->io_list)) {
10434                 list_del_init(&block_group->io_list);
10435
10436                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10437
10438                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10439                 btrfs_wait_cache_io(trans, block_group, path);
10440                 btrfs_put_block_group(block_group);
10441                 spin_lock(&trans->transaction->dirty_bgs_lock);
10442         }
10443
10444         if (!list_empty(&block_group->dirty_list)) {
10445                 list_del_init(&block_group->dirty_list);
10446                 btrfs_put_block_group(block_group);
10447         }
10448         spin_unlock(&trans->transaction->dirty_bgs_lock);
10449         mutex_unlock(&trans->transaction->cache_write_mutex);
10450
10451         if (!IS_ERR(inode)) {
10452                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10453                 if (ret) {
10454                         btrfs_add_delayed_iput(inode);
10455                         goto out;
10456                 }
10457                 clear_nlink(inode);
10458                 /* One for the block groups ref */
10459                 spin_lock(&block_group->lock);
10460                 if (block_group->iref) {
10461                         block_group->iref = 0;
10462                         block_group->inode = NULL;
10463                         spin_unlock(&block_group->lock);
10464                         iput(inode);
10465                 } else {
10466                         spin_unlock(&block_group->lock);
10467                 }
10468                 /* One for our lookup ref */
10469                 btrfs_add_delayed_iput(inode);
10470         }
10471
10472         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10473         key.offset = block_group->key.objectid;
10474         key.type = 0;
10475
10476         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10477         if (ret < 0)
10478                 goto out;
10479         if (ret > 0)
10480                 btrfs_release_path(path);
10481         if (ret == 0) {
10482                 ret = btrfs_del_item(trans, tree_root, path);
10483                 if (ret)
10484                         goto out;
10485                 btrfs_release_path(path);
10486         }
10487
10488         spin_lock(&fs_info->block_group_cache_lock);
10489         rb_erase(&block_group->cache_node,
10490                  &fs_info->block_group_cache_tree);
10491         RB_CLEAR_NODE(&block_group->cache_node);
10492
10493         if (fs_info->first_logical_byte == block_group->key.objectid)
10494                 fs_info->first_logical_byte = (u64)-1;
10495         spin_unlock(&fs_info->block_group_cache_lock);
10496
10497         down_write(&block_group->space_info->groups_sem);
10498         /*
10499          * we must use list_del_init so people can check to see if they
10500          * are still on the list after taking the semaphore
10501          */
10502         list_del_init(&block_group->list);
10503         if (list_empty(&block_group->space_info->block_groups[index])) {
10504                 kobj = block_group->space_info->block_group_kobjs[index];
10505                 block_group->space_info->block_group_kobjs[index] = NULL;
10506                 clear_avail_alloc_bits(fs_info, block_group->flags);
10507         }
10508         up_write(&block_group->space_info->groups_sem);
10509         if (kobj) {
10510                 kobject_del(kobj);
10511                 kobject_put(kobj);
10512         }
10513
10514         if (block_group->has_caching_ctl)
10515                 caching_ctl = get_caching_control(block_group);
10516         if (block_group->cached == BTRFS_CACHE_STARTED)
10517                 wait_block_group_cache_done(block_group);
10518         if (block_group->has_caching_ctl) {
10519                 down_write(&fs_info->commit_root_sem);
10520                 if (!caching_ctl) {
10521                         struct btrfs_caching_control *ctl;
10522
10523                         list_for_each_entry(ctl,
10524                                     &fs_info->caching_block_groups, list)
10525                                 if (ctl->block_group == block_group) {
10526                                         caching_ctl = ctl;
10527                                         refcount_inc(&caching_ctl->count);
10528                                         break;
10529                                 }
10530                 }
10531                 if (caching_ctl)
10532                         list_del_init(&caching_ctl->list);
10533                 up_write(&fs_info->commit_root_sem);
10534                 if (caching_ctl) {
10535                         /* Once for the caching bgs list and once for us. */
10536                         put_caching_control(caching_ctl);
10537                         put_caching_control(caching_ctl);
10538                 }
10539         }
10540
10541         spin_lock(&trans->transaction->dirty_bgs_lock);
10542         if (!list_empty(&block_group->dirty_list)) {
10543                 WARN_ON(1);
10544         }
10545         if (!list_empty(&block_group->io_list)) {
10546                 WARN_ON(1);
10547         }
10548         spin_unlock(&trans->transaction->dirty_bgs_lock);
10549         btrfs_remove_free_space_cache(block_group);
10550
10551         spin_lock(&block_group->space_info->lock);
10552         list_del_init(&block_group->ro_list);
10553
10554         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
10555                 WARN_ON(block_group->space_info->total_bytes
10556                         < block_group->key.offset);
10557                 WARN_ON(block_group->space_info->bytes_readonly
10558                         < block_group->key.offset);
10559                 WARN_ON(block_group->space_info->disk_total
10560                         < block_group->key.offset * factor);
10561         }
10562         block_group->space_info->total_bytes -= block_group->key.offset;
10563         block_group->space_info->bytes_readonly -= block_group->key.offset;
10564         block_group->space_info->disk_total -= block_group->key.offset * factor;
10565
10566         spin_unlock(&block_group->space_info->lock);
10567
10568         memcpy(&key, &block_group->key, sizeof(key));
10569
10570         mutex_lock(&fs_info->chunk_mutex);
10571         if (!list_empty(&em->list)) {
10572                 /* We're in the transaction->pending_chunks list. */
10573                 free_extent_map(em);
10574         }
10575         spin_lock(&block_group->lock);
10576         block_group->removed = 1;
10577         /*
10578          * At this point trimming can't start on this block group, because we
10579          * removed the block group from the tree fs_info->block_group_cache_tree
10580          * so no one can't find it anymore and even if someone already got this
10581          * block group before we removed it from the rbtree, they have already
10582          * incremented block_group->trimming - if they didn't, they won't find
10583          * any free space entries because we already removed them all when we
10584          * called btrfs_remove_free_space_cache().
10585          *
10586          * And we must not remove the extent map from the fs_info->mapping_tree
10587          * to prevent the same logical address range and physical device space
10588          * ranges from being reused for a new block group. This is because our
10589          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10590          * completely transactionless, so while it is trimming a range the
10591          * currently running transaction might finish and a new one start,
10592          * allowing for new block groups to be created that can reuse the same
10593          * physical device locations unless we take this special care.
10594          *
10595          * There may also be an implicit trim operation if the file system
10596          * is mounted with -odiscard. The same protections must remain
10597          * in place until the extents have been discarded completely when
10598          * the transaction commit has completed.
10599          */
10600         remove_em = (atomic_read(&block_group->trimming) == 0);
10601         /*
10602          * Make sure a trimmer task always sees the em in the pinned_chunks list
10603          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10604          * before checking block_group->removed).
10605          */
10606         if (!remove_em) {
10607                 /*
10608                  * Our em might be in trans->transaction->pending_chunks which
10609                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10610                  * and so is the fs_info->pinned_chunks list.
10611                  *
10612                  * So at this point we must be holding the chunk_mutex to avoid
10613                  * any races with chunk allocation (more specifically at
10614                  * volumes.c:contains_pending_extent()), to ensure it always
10615                  * sees the em, either in the pending_chunks list or in the
10616                  * pinned_chunks list.
10617                  */
10618                 list_move_tail(&em->list, &fs_info->pinned_chunks);
10619         }
10620         spin_unlock(&block_group->lock);
10621
10622         if (remove_em) {
10623                 struct extent_map_tree *em_tree;
10624
10625                 em_tree = &fs_info->mapping_tree.map_tree;
10626                 write_lock(&em_tree->lock);
10627                 /*
10628                  * The em might be in the pending_chunks list, so make sure the
10629                  * chunk mutex is locked, since remove_extent_mapping() will
10630                  * delete us from that list.
10631                  */
10632                 remove_extent_mapping(em_tree, em);
10633                 write_unlock(&em_tree->lock);
10634                 /* once for the tree */
10635                 free_extent_map(em);
10636         }
10637
10638         mutex_unlock(&fs_info->chunk_mutex);
10639
10640         ret = remove_block_group_free_space(trans, fs_info, block_group);
10641         if (ret)
10642                 goto out;
10643
10644         btrfs_put_block_group(block_group);
10645         btrfs_put_block_group(block_group);
10646
10647         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10648         if (ret > 0)
10649                 ret = -EIO;
10650         if (ret < 0)
10651                 goto out;
10652
10653         ret = btrfs_del_item(trans, root, path);
10654 out:
10655         btrfs_free_path(path);
10656         return ret;
10657 }
10658
10659 struct btrfs_trans_handle *
10660 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10661                                      const u64 chunk_offset)
10662 {
10663         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10664         struct extent_map *em;
10665         struct map_lookup *map;
10666         unsigned int num_items;
10667
10668         read_lock(&em_tree->lock);
10669         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10670         read_unlock(&em_tree->lock);
10671         ASSERT(em && em->start == chunk_offset);
10672
10673         /*
10674          * We need to reserve 3 + N units from the metadata space info in order
10675          * to remove a block group (done at btrfs_remove_chunk() and at
10676          * btrfs_remove_block_group()), which are used for:
10677          *
10678          * 1 unit for adding the free space inode's orphan (located in the tree
10679          * of tree roots).
10680          * 1 unit for deleting the block group item (located in the extent
10681          * tree).
10682          * 1 unit for deleting the free space item (located in tree of tree
10683          * roots).
10684          * N units for deleting N device extent items corresponding to each
10685          * stripe (located in the device tree).
10686          *
10687          * In order to remove a block group we also need to reserve units in the
10688          * system space info in order to update the chunk tree (update one or
10689          * more device items and remove one chunk item), but this is done at
10690          * btrfs_remove_chunk() through a call to check_system_chunk().
10691          */
10692         map = em->map_lookup;
10693         num_items = 3 + map->num_stripes;
10694         free_extent_map(em);
10695
10696         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10697                                                            num_items, 1);
10698 }
10699
10700 /*
10701  * Process the unused_bgs list and remove any that don't have any allocated
10702  * space inside of them.
10703  */
10704 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10705 {
10706         struct btrfs_block_group_cache *block_group;
10707         struct btrfs_space_info *space_info;
10708         struct btrfs_trans_handle *trans;
10709         int ret = 0;
10710
10711         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10712                 return;
10713
10714         spin_lock(&fs_info->unused_bgs_lock);
10715         while (!list_empty(&fs_info->unused_bgs)) {
10716                 u64 start, end;
10717                 int trimming;
10718
10719                 block_group = list_first_entry(&fs_info->unused_bgs,
10720                                                struct btrfs_block_group_cache,
10721                                                bg_list);
10722                 list_del_init(&block_group->bg_list);
10723
10724                 space_info = block_group->space_info;
10725
10726                 if (ret || btrfs_mixed_space_info(space_info)) {
10727                         btrfs_put_block_group(block_group);
10728                         continue;
10729                 }
10730                 spin_unlock(&fs_info->unused_bgs_lock);
10731
10732                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10733
10734                 /* Don't want to race with allocators so take the groups_sem */
10735                 down_write(&space_info->groups_sem);
10736                 spin_lock(&block_group->lock);
10737                 if (block_group->reserved ||
10738                     btrfs_block_group_used(&block_group->item) ||
10739                     block_group->ro ||
10740                     list_is_singular(&block_group->list)) {
10741                         /*
10742                          * We want to bail if we made new allocations or have
10743                          * outstanding allocations in this block group.  We do
10744                          * the ro check in case balance is currently acting on
10745                          * this block group.
10746                          */
10747                         spin_unlock(&block_group->lock);
10748                         up_write(&space_info->groups_sem);
10749                         goto next;
10750                 }
10751                 spin_unlock(&block_group->lock);
10752
10753                 /* We don't want to force the issue, only flip if it's ok. */
10754                 ret = inc_block_group_ro(block_group, 0);
10755                 up_write(&space_info->groups_sem);
10756                 if (ret < 0) {
10757                         ret = 0;
10758                         goto next;
10759                 }
10760
10761                 /*
10762                  * Want to do this before we do anything else so we can recover
10763                  * properly if we fail to join the transaction.
10764                  */
10765                 trans = btrfs_start_trans_remove_block_group(fs_info,
10766                                                      block_group->key.objectid);
10767                 if (IS_ERR(trans)) {
10768                         btrfs_dec_block_group_ro(block_group);
10769                         ret = PTR_ERR(trans);
10770                         goto next;
10771                 }
10772
10773                 /*
10774                  * We could have pending pinned extents for this block group,
10775                  * just delete them, we don't care about them anymore.
10776                  */
10777                 start = block_group->key.objectid;
10778                 end = start + block_group->key.offset - 1;
10779                 /*
10780                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10781                  * btrfs_finish_extent_commit(). If we are at transaction N,
10782                  * another task might be running finish_extent_commit() for the
10783                  * previous transaction N - 1, and have seen a range belonging
10784                  * to the block group in freed_extents[] before we were able to
10785                  * clear the whole block group range from freed_extents[]. This
10786                  * means that task can lookup for the block group after we
10787                  * unpinned it from freed_extents[] and removed it, leading to
10788                  * a BUG_ON() at btrfs_unpin_extent_range().
10789                  */
10790                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10791                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10792                                   EXTENT_DIRTY);
10793                 if (ret) {
10794                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10795                         btrfs_dec_block_group_ro(block_group);
10796                         goto end_trans;
10797                 }
10798                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10799                                   EXTENT_DIRTY);
10800                 if (ret) {
10801                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10802                         btrfs_dec_block_group_ro(block_group);
10803                         goto end_trans;
10804                 }
10805                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10806
10807                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10808                 spin_lock(&space_info->lock);
10809                 spin_lock(&block_group->lock);
10810
10811                 space_info->bytes_pinned -= block_group->pinned;
10812                 space_info->bytes_readonly += block_group->pinned;
10813                 percpu_counter_add(&space_info->total_bytes_pinned,
10814                                    -block_group->pinned);
10815                 block_group->pinned = 0;
10816
10817                 spin_unlock(&block_group->lock);
10818                 spin_unlock(&space_info->lock);
10819
10820                 /* DISCARD can flip during remount */
10821                 trimming = btrfs_test_opt(fs_info, DISCARD);
10822
10823                 /* Implicit trim during transaction commit. */
10824                 if (trimming)
10825                         btrfs_get_block_group_trimming(block_group);
10826
10827                 /*
10828                  * Btrfs_remove_chunk will abort the transaction if things go
10829                  * horribly wrong.
10830                  */
10831                 ret = btrfs_remove_chunk(trans, fs_info,
10832                                          block_group->key.objectid);
10833
10834                 if (ret) {
10835                         if (trimming)
10836                                 btrfs_put_block_group_trimming(block_group);
10837                         goto end_trans;
10838                 }
10839
10840                 /*
10841                  * If we're not mounted with -odiscard, we can just forget
10842                  * about this block group. Otherwise we'll need to wait
10843                  * until transaction commit to do the actual discard.
10844                  */
10845                 if (trimming) {
10846                         spin_lock(&fs_info->unused_bgs_lock);
10847                         /*
10848                          * A concurrent scrub might have added us to the list
10849                          * fs_info->unused_bgs, so use a list_move operation
10850                          * to add the block group to the deleted_bgs list.
10851                          */
10852                         list_move(&block_group->bg_list,
10853                                   &trans->transaction->deleted_bgs);
10854                         spin_unlock(&fs_info->unused_bgs_lock);
10855                         btrfs_get_block_group(block_group);
10856                 }
10857 end_trans:
10858                 btrfs_end_transaction(trans);
10859 next:
10860                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10861                 btrfs_put_block_group(block_group);
10862                 spin_lock(&fs_info->unused_bgs_lock);
10863         }
10864         spin_unlock(&fs_info->unused_bgs_lock);
10865 }
10866
10867 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10868 {
10869         struct btrfs_space_info *space_info;
10870         struct btrfs_super_block *disk_super;
10871         u64 features;
10872         u64 flags;
10873         int mixed = 0;
10874         int ret;
10875
10876         disk_super = fs_info->super_copy;
10877         if (!btrfs_super_root(disk_super))
10878                 return -EINVAL;
10879
10880         features = btrfs_super_incompat_flags(disk_super);
10881         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10882                 mixed = 1;
10883
10884         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10885         ret = create_space_info(fs_info, flags, &space_info);
10886         if (ret)
10887                 goto out;
10888
10889         if (mixed) {
10890                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10891                 ret = create_space_info(fs_info, flags, &space_info);
10892         } else {
10893                 flags = BTRFS_BLOCK_GROUP_METADATA;
10894                 ret = create_space_info(fs_info, flags, &space_info);
10895                 if (ret)
10896                         goto out;
10897
10898                 flags = BTRFS_BLOCK_GROUP_DATA;
10899                 ret = create_space_info(fs_info, flags, &space_info);
10900         }
10901 out:
10902         return ret;
10903 }
10904
10905 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
10906                                    u64 start, u64 end)
10907 {
10908         return unpin_extent_range(fs_info, start, end, false);
10909 }
10910
10911 /*
10912  * It used to be that old block groups would be left around forever.
10913  * Iterating over them would be enough to trim unused space.  Since we
10914  * now automatically remove them, we also need to iterate over unallocated
10915  * space.
10916  *
10917  * We don't want a transaction for this since the discard may take a
10918  * substantial amount of time.  We don't require that a transaction be
10919  * running, but we do need to take a running transaction into account
10920  * to ensure that we're not discarding chunks that were released in
10921  * the current transaction.
10922  *
10923  * Holding the chunks lock will prevent other threads from allocating
10924  * or releasing chunks, but it won't prevent a running transaction
10925  * from committing and releasing the memory that the pending chunks
10926  * list head uses.  For that, we need to take a reference to the
10927  * transaction.
10928  */
10929 static int btrfs_trim_free_extents(struct btrfs_device *device,
10930                                    u64 minlen, u64 *trimmed)
10931 {
10932         u64 start = 0, len = 0;
10933         int ret;
10934
10935         *trimmed = 0;
10936
10937         /* Not writeable = nothing to do. */
10938         if (!device->writeable)
10939                 return 0;
10940
10941         /* No free space = nothing to do. */
10942         if (device->total_bytes <= device->bytes_used)
10943                 return 0;
10944
10945         ret = 0;
10946
10947         while (1) {
10948                 struct btrfs_fs_info *fs_info = device->fs_info;
10949                 struct btrfs_transaction *trans;
10950                 u64 bytes;
10951
10952                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10953                 if (ret)
10954                         return ret;
10955
10956                 down_read(&fs_info->commit_root_sem);
10957
10958                 spin_lock(&fs_info->trans_lock);
10959                 trans = fs_info->running_transaction;
10960                 if (trans)
10961                         refcount_inc(&trans->use_count);
10962                 spin_unlock(&fs_info->trans_lock);
10963
10964                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10965                                                  &start, &len);
10966                 if (trans)
10967                         btrfs_put_transaction(trans);
10968
10969                 if (ret) {
10970                         up_read(&fs_info->commit_root_sem);
10971                         mutex_unlock(&fs_info->chunk_mutex);
10972                         if (ret == -ENOSPC)
10973                                 ret = 0;
10974                         break;
10975                 }
10976
10977                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10978                 up_read(&fs_info->commit_root_sem);
10979                 mutex_unlock(&fs_info->chunk_mutex);
10980
10981                 if (ret)
10982                         break;
10983
10984                 start += len;
10985                 *trimmed += bytes;
10986
10987                 if (fatal_signal_pending(current)) {
10988                         ret = -ERESTARTSYS;
10989                         break;
10990                 }
10991
10992                 cond_resched();
10993         }
10994
10995         return ret;
10996 }
10997
10998 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
10999 {
11000         struct btrfs_block_group_cache *cache = NULL;
11001         struct btrfs_device *device;
11002         struct list_head *devices;
11003         u64 group_trimmed;
11004         u64 start;
11005         u64 end;
11006         u64 trimmed = 0;
11007         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
11008         int ret = 0;
11009
11010         /*
11011          * try to trim all FS space, our block group may start from non-zero.
11012          */
11013         if (range->len == total_bytes)
11014                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
11015         else
11016                 cache = btrfs_lookup_block_group(fs_info, range->start);
11017
11018         while (cache) {
11019                 if (cache->key.objectid >= (range->start + range->len)) {
11020                         btrfs_put_block_group(cache);
11021                         break;
11022                 }
11023
11024                 start = max(range->start, cache->key.objectid);
11025                 end = min(range->start + range->len,
11026                                 cache->key.objectid + cache->key.offset);
11027
11028                 if (end - start >= range->minlen) {
11029                         if (!block_group_cache_done(cache)) {
11030                                 ret = cache_block_group(cache, 0);
11031                                 if (ret) {
11032                                         btrfs_put_block_group(cache);
11033                                         break;
11034                                 }
11035                                 ret = wait_block_group_cache_done(cache);
11036                                 if (ret) {
11037                                         btrfs_put_block_group(cache);
11038                                         break;
11039                                 }
11040                         }
11041                         ret = btrfs_trim_block_group(cache,
11042                                                      &group_trimmed,
11043                                                      start,
11044                                                      end,
11045                                                      range->minlen);
11046
11047                         trimmed += group_trimmed;
11048                         if (ret) {
11049                                 btrfs_put_block_group(cache);
11050                                 break;
11051                         }
11052                 }
11053
11054                 cache = next_block_group(fs_info, cache);
11055         }
11056
11057         mutex_lock(&fs_info->fs_devices->device_list_mutex);
11058         devices = &fs_info->fs_devices->alloc_list;
11059         list_for_each_entry(device, devices, dev_alloc_list) {
11060                 ret = btrfs_trim_free_extents(device, range->minlen,
11061                                               &group_trimmed);
11062                 if (ret)
11063                         break;
11064
11065                 trimmed += group_trimmed;
11066         }
11067         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
11068
11069         range->len = trimmed;
11070         return ret;
11071 }
11072
11073 /*
11074  * btrfs_{start,end}_write_no_snapshotting() are similar to
11075  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11076  * data into the page cache through nocow before the subvolume is snapshoted,
11077  * but flush the data into disk after the snapshot creation, or to prevent
11078  * operations while snapshotting is ongoing and that cause the snapshot to be
11079  * inconsistent (writes followed by expanding truncates for example).
11080  */
11081 void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
11082 {
11083         percpu_counter_dec(&root->subv_writers->counter);
11084         /*
11085          * Make sure counter is updated before we wake up waiters.
11086          */
11087         smp_mb();
11088         if (waitqueue_active(&root->subv_writers->wait))
11089                 wake_up(&root->subv_writers->wait);
11090 }
11091
11092 int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
11093 {
11094         if (atomic_read(&root->will_be_snapshotted))
11095                 return 0;
11096
11097         percpu_counter_inc(&root->subv_writers->counter);
11098         /*
11099          * Make sure counter is updated before we check for snapshot creation.
11100          */
11101         smp_mb();
11102         if (atomic_read(&root->will_be_snapshotted)) {
11103                 btrfs_end_write_no_snapshotting(root);
11104                 return 0;
11105         }
11106         return 1;
11107 }
11108
11109 static int wait_snapshotting_atomic_t(atomic_t *a)
11110 {
11111         schedule();
11112         return 0;
11113 }
11114
11115 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11116 {
11117         while (true) {
11118                 int ret;
11119
11120                 ret = btrfs_start_write_no_snapshotting(root);
11121                 if (ret)
11122                         break;
11123                 wait_on_atomic_t(&root->will_be_snapshotted,
11124                                  wait_snapshotting_atomic_t,
11125                                  TASK_UNINTERRUPTIBLE);
11126         }
11127 }