fs/btrfs/extent-tree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/sched/signal.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/writeback.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/sort.h>
  12 #include <linux/rcupdate.h>
  13 #include <linux/kthread.h>
  14 #include <linux/slab.h>
  15 #include <linux/ratelimit.h>
  16 #include <linux/percpu_counter.h>
  17 #include <linux/lockdep.h>
  18 #include <linux/crc32c.h>
  19 #include "tree-log.h"
  20 #include "disk-io.h"
  21 #include "print-tree.h"
  22 #include "volumes.h"
  23 #include "raid56.h"
  24 #include "locking.h"
  25 #include "free-space-cache.h"
  26 #include "free-space-tree.h"
  27 #include "math.h"
  28 #include "sysfs.h"
  29 #include "qgroup.h"
  30 #include "ref-verify.h"
  31
  32 #undef SCRAMBLE_DELAYED_REFS
  33
  34 /*
  35  * control flags for do_chunk_alloc's force field
  36  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  37  * if we really need one.
  38  *
  39  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  40  * if we have very few chunks already allocated.  This is
  41  * used as part of the clustering code to help make sure
  42  * we have a good pool of storage to cluster in, without
  43  * filling the FS with empty chunks
  44  *
  45  * CHUNK_ALLOC_FORCE means it must try to allocate one
  46  *
  47  */
  48 enum {
  49         CHUNK_ALLOC_NO_FORCE = 0,
  50         CHUNK_ALLOC_LIMITED = 1,
  51         CHUNK_ALLOC_FORCE = 2,
  52 };
  53
  54 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  55                                struct btrfs_fs_info *fs_info,
  56                                 struct btrfs_delayed_ref_node *node, u64 parent,
  57                                 u64 root_objectid, u64 owner_objectid,
  58                                 u64 owner_offset, int refs_to_drop,
  59                                 struct btrfs_delayed_extent_op *extra_op);
  60 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  61                                     struct extent_buffer *leaf,
  62                                     struct btrfs_extent_item *ei);
  63 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  64                                       struct btrfs_fs_info *fs_info,
  65                                       u64 parent, u64 root_objectid,
  66                                       u64 flags, u64 owner, u64 offset,
  67                                       struct btrfs_key *ins, int ref_mod);
  68 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  69                                      struct btrfs_delayed_ref_node *node,
  70                                      struct btrfs_delayed_extent_op *extent_op);
  71 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  72                           struct btrfs_fs_info *fs_info, u64 flags,
  73                           int force);
  74 static int find_next_key(struct btrfs_path *path, int level,
  75                          struct btrfs_key *key);
  76 static void dump_space_info(struct btrfs_fs_info *fs_info,
  77                             struct btrfs_space_info *info, u64 bytes,
  78                             int dump_block_groups);
  79 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
  80                                u64 num_bytes);
  81 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
  82                                      struct btrfs_space_info *space_info,
  83                                      u64 num_bytes);
  84 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
  85                                      struct btrfs_space_info *space_info,
  86                                      u64 num_bytes);
  87
  88 static noinline int
  89 block_group_cache_done(struct btrfs_block_group_cache *cache)
  90 {
  91         smp_mb();
  92         return cache->cached == BTRFS_CACHE_FINISHED ||
  93                 cache->cached == BTRFS_CACHE_ERROR;
  94 }
  95
  96 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  97 {
  98         return (cache->flags & bits) == bits;
  99 }
 100
 101 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 102 {
 103         atomic_inc(&cache->count);
 104 }
 105
 106 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 107 {
 108         if (atomic_dec_and_test(&cache->count)) {
 109                 WARN_ON(cache->pinned > 0);
 110                 WARN_ON(cache->reserved > 0);
 111
 112                 /*
 113                  * If not empty, someone is still holding mutex of
 114                  * full_stripe_lock, which can only be released by caller.
 115                  * And it will definitely cause use-after-free when caller
 116                  * tries to release full stripe lock.
 117                  *
 118                  * No better way to resolve, but only to warn.
 119                  */
 120                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 121                 kfree(cache->free_space_ctl);
 122                 kfree(cache);
 123         }
 124 }
 125
 126 /*
 127  * this adds the block group to the fs_info rb tree for the block group
 128  * cache
 129  */
 130 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 131                                 struct btrfs_block_group_cache *block_group)
 132 {
 133         struct rb_node **p;
 134         struct rb_node *parent = NULL;
 135         struct btrfs_block_group_cache *cache;
 136
 137         spin_lock(&info->block_group_cache_lock);
 138         p = &info->block_group_cache_tree.rb_node;
 139
 140         while (*p) {
 141                 parent = *p;
 142                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 143                                  cache_node);
 144                 if (block_group->key.objectid < cache->key.objectid) {
 145                         p = &(*p)->rb_left;
 146                 } else if (block_group->key.objectid > cache->key.objectid) {
 147                         p = &(*p)->rb_right;
 148                 } else {
 149                         spin_unlock(&info->block_group_cache_lock);
 150                         return -EEXIST;
 151                 }
 152         }
 153
 154         rb_link_node(&block_group->cache_node, parent, p);
 155         rb_insert_color(&block_group->cache_node,
 156                         &info->block_group_cache_tree);
 157
 158         if (info->first_logical_byte > block_group->key.objectid)
 159                 info->first_logical_byte = block_group->key.objectid;
 160
 161         spin_unlock(&info->block_group_cache_lock);
 162
 163         return 0;
 164 }
 165
 166 /*
 167  * This will return the block group at or after bytenr if contains is 0, else
 168  * it will return the block group that contains the bytenr
 169  */
 170 static struct btrfs_block_group_cache *
 171 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 172                               int contains)
 173 {
 174         struct btrfs_block_group_cache *cache, *ret = NULL;
 175         struct rb_node *n;
 176         u64 end, start;
 177
 178         spin_lock(&info->block_group_cache_lock);
 179         n = info->block_group_cache_tree.rb_node;
 180
 181         while (n) {
 182                 cache = rb_entry(n, struct btrfs_block_group_cache,
 183                                  cache_node);
 184                 end = cache->key.objectid + cache->key.offset - 1;
 185                 start = cache->key.objectid;
 186
 187                 if (bytenr < start) {
 188                         if (!contains && (!ret || start < ret->key.objectid))
 189                                 ret = cache;
 190                         n = n->rb_left;
 191                 } else if (bytenr > start) {
 192                         if (contains && bytenr <= end) {
 193                                 ret = cache;
 194                                 break;
 195                         }
 196                         n = n->rb_right;
 197                 } else {
 198                         ret = cache;
 199                         break;
 200                 }
 201         }
 202         if (ret) {
 203                 btrfs_get_block_group(ret);
 204                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 205                         info->first_logical_byte = ret->key.objectid;
 206         }
 207         spin_unlock(&info->block_group_cache_lock);
 208
 209         return ret;
 210 }
 211
 212 static int add_excluded_extent(struct btrfs_fs_info *fs_info,
 213                                u64 start, u64 num_bytes)
 214 {
 215         u64 end = start + num_bytes - 1;
 216         set_extent_bits(&fs_info->freed_extents[0],
 217                         start, end, EXTENT_UPTODATE);
 218         set_extent_bits(&fs_info->freed_extents[1],
 219                         start, end, EXTENT_UPTODATE);
 220         return 0;
 221 }
 222
 223 static void free_excluded_extents(struct btrfs_fs_info *fs_info,
 224                                   struct btrfs_block_group_cache *cache)
 225 {
 226         u64 start, end;
 227
 228         start = cache->key.objectid;
 229         end = start + cache->key.offset - 1;
 230
 231         clear_extent_bits(&fs_info->freed_extents[0],
 232                           start, end, EXTENT_UPTODATE);
 233         clear_extent_bits(&fs_info->freed_extents[1],
 234                           start, end, EXTENT_UPTODATE);
 235 }
 236
 237 static int exclude_super_stripes(struct btrfs_fs_info *fs_info,
 238                                  struct btrfs_block_group_cache *cache)
 239 {
 240         u64 bytenr;
 241         u64 *logical;
 242         int stripe_len;
 243         int i, nr, ret;
 244
 245         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 246                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 247                 cache->bytes_super += stripe_len;
 248                 ret = add_excluded_extent(fs_info, cache->key.objectid,
 249                                           stripe_len);
 250                 if (ret)
 251                         return ret;
 252         }
 253
 254         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 255                 bytenr = btrfs_sb_offset(i);
 256                 ret = btrfs_rmap_block(fs_info, cache->key.objectid,
 257                                        bytenr, &logical, &nr, &stripe_len);
 258                 if (ret)
 259                         return ret;
 260
 261                 while (nr--) {
 262                         u64 start, len;
 263
 264                         if (logical[nr] > cache->key.objectid +
 265                             cache->key.offset)
 266                                 continue;
 267
 268                         if (logical[nr] + stripe_len <= cache->key.objectid)
 269                                 continue;
 270
 271                         start = logical[nr];
 272                         if (start < cache->key.objectid) {
 273                                 start = cache->key.objectid;
 274                                 len = (logical[nr] + stripe_len) - start;
 275                         } else {
 276                                 len = min_t(u64, stripe_len,
 277                                             cache->key.objectid +
 278                                             cache->key.offset - start);
 279                         }
 280
 281                         cache->bytes_super += len;
 282                         ret = add_excluded_extent(fs_info, start, len);
 283                         if (ret) {
 284                                 kfree(logical);
 285                                 return ret;
 286                         }
 287                 }
 288
 289                 kfree(logical);
 290         }
 291         return 0;
 292 }
 293
 294 static struct btrfs_caching_control *
 295 get_caching_control(struct btrfs_block_group_cache *cache)
 296 {
 297         struct btrfs_caching_control *ctl;
 298
 299         spin_lock(&cache->lock);
 300         if (!cache->caching_ctl) {
 301                 spin_unlock(&cache->lock);
 302                 return NULL;
 303         }
 304
 305         ctl = cache->caching_ctl;
 306         refcount_inc(&ctl->count);
 307         spin_unlock(&cache->lock);
 308         return ctl;
 309 }
 310
 311 static void put_caching_control(struct btrfs_caching_control *ctl)
 312 {
 313         if (refcount_dec_and_test(&ctl->count))
 314                 kfree(ctl);
 315 }
 316
 317 #ifdef CONFIG_BTRFS_DEBUG
 318 static void fragment_free_space(struct btrfs_block_group_cache *block_group)
 319 {
 320         struct btrfs_fs_info *fs_info = block_group->fs_info;
 321         u64 start = block_group->key.objectid;
 322         u64 len = block_group->key.offset;
 323         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 324                 fs_info->nodesize : fs_info->sectorsize;
 325         u64 step = chunk << 1;
 326
 327         while (len > chunk) {
 328                 btrfs_remove_free_space(block_group, start, chunk);
 329                 start += step;
 330                 if (len < step)
 331                         len = 0;
 332                 else
 333                         len -= step;
 334         }
 335 }
 336 #endif
 337
 338 /*
 339  * this is only called by cache_block_group, since we could have freed extents
 340  * we need to check the pinned_extents for any extents that can't be used yet
 341  * since their free space will be released as soon as the transaction commits.
 342  */
 343 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 344                        u64 start, u64 end)
 345 {
 346         struct btrfs_fs_info *info = block_group->fs_info;
 347         u64 extent_start, extent_end, size, total_added = 0;
 348         int ret;
 349
 350         while (start < end) {
 351                 ret = find_first_extent_bit(info->pinned_extents, start,
 352                                             &extent_start, &extent_end,
 353                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 354                                             NULL);
 355                 if (ret)
 356                         break;
 357
 358                 if (extent_start <= start) {
 359                         start = extent_end + 1;
 360                 } else if (extent_start > start && extent_start < end) {
 361                         size = extent_start - start;
 362                         total_added += size;
 363                         ret = btrfs_add_free_space(block_group, start,
 364                                                    size);
 365                         BUG_ON(ret); /* -ENOMEM or logic error */
 366                         start = extent_end + 1;
 367                 } else {
 368                         break;
 369                 }
 370         }
 371
 372         if (start < end) {
 373                 size = end - start;
 374                 total_added += size;
 375                 ret = btrfs_add_free_space(block_group, start, size);
 376                 BUG_ON(ret); /* -ENOMEM or logic error */
 377         }
 378
 379         return total_added;
 380 }
 381
 382 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 383 {
 384         struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
 385         struct btrfs_fs_info *fs_info = block_group->fs_info;
 386         struct btrfs_root *extent_root = fs_info->extent_root;
 387         struct btrfs_path *path;
 388         struct extent_buffer *leaf;
 389         struct btrfs_key key;
 390         u64 total_found = 0;
 391         u64 last = 0;
 392         u32 nritems;
 393         int ret;
 394         bool wakeup = true;
 395
 396         path = btrfs_alloc_path();
 397         if (!path)
 398                 return -ENOMEM;
 399
 400         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 401
 402 #ifdef CONFIG_BTRFS_DEBUG
 403         /*
 404          * If we're fragmenting we don't want to make anybody think we can
 405          * allocate from this block group until we've had a chance to fragment
 406          * the free space.
 407          */
 408         if (btrfs_should_fragment_free_space(block_group))
 409                 wakeup = false;
 410 #endif
 411         /*
 412          * We don't want to deadlock with somebody trying to allocate a new
 413          * extent for the extent root while also trying to search the extent
 414          * root to add free space.  So we skip locking and search the commit
 415          * root, since its read-only
 416          */
 417         path->skip_locking = 1;
 418         path->search_commit_root = 1;
 419         path->reada = READA_FORWARD;
 420
 421         key.objectid = last;
 422         key.offset = 0;
 423         key.type = BTRFS_EXTENT_ITEM_KEY;
 424
 425 next:
 426         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 427         if (ret < 0)
 428                 goto out;
 429
 430         leaf = path->nodes[0];
 431         nritems = btrfs_header_nritems(leaf);
 432
 433         while (1) {
 434                 if (btrfs_fs_closing(fs_info) > 1) {
 435                         last = (u64)-1;
 436                         break;
 437                 }
 438
 439                 if (path->slots[0] < nritems) {
 440                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 441                 } else {
 442                         ret = find_next_key(path, 0, &key);
 443                         if (ret)
 444                                 break;
 445
 446                         if (need_resched() ||
 447                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 448                                 if (wakeup)
 449                                         caching_ctl->progress = last;
 450                                 btrfs_release_path(path);
 451                                 up_read(&fs_info->commit_root_sem);
 452                                 mutex_unlock(&caching_ctl->mutex);
 453                                 cond_resched();
 454                                 mutex_lock(&caching_ctl->mutex);
 455                                 down_read(&fs_info->commit_root_sem);
 456                                 goto next;
 457                         }
 458
 459                         ret = btrfs_next_leaf(extent_root, path);
 460                         if (ret < 0)
 461                                 goto out;
 462                         if (ret)
 463                                 break;
 464                         leaf = path->nodes[0];
 465                         nritems = btrfs_header_nritems(leaf);
 466                         continue;
 467                 }
 468
 469                 if (key.objectid < last) {
 470                         key.objectid = last;
 471                         key.offset = 0;
 472                         key.type = BTRFS_EXTENT_ITEM_KEY;
 473
 474                         if (wakeup)
 475                                 caching_ctl->progress = last;
 476                         btrfs_release_path(path);
 477                         goto next;
 478                 }
 479
 480                 if (key.objectid < block_group->key.objectid) {
 481                         path->slots[0]++;
 482                         continue;
 483                 }
 484
 485                 if (key.objectid >= block_group->key.objectid +
 486                     block_group->key.offset)
 487                         break;
 488
 489                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 490                     key.type == BTRFS_METADATA_ITEM_KEY) {
 491                         total_found += add_new_free_space(block_group, last,
 492                                                           key.objectid);
 493                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 494                                 last = key.objectid +
 495                                         fs_info->nodesize;
 496                         else
 497                                 last = key.objectid + key.offset;
 498
 499                         if (total_found > CACHING_CTL_WAKE_UP) {
 500                                 total_found = 0;
 501                                 if (wakeup)
 502                                         wake_up(&caching_ctl->wait);
 503                         }
 504                 }
 505                 path->slots[0]++;
 506         }
 507         ret = 0;
 508
 509         total_found += add_new_free_space(block_group, last,
 510                                           block_group->key.objectid +
 511                                           block_group->key.offset);
 512         caching_ctl->progress = (u64)-1;
 513
 514 out:
 515         btrfs_free_path(path);
 516         return ret;
 517 }
 518
 519 static noinline void caching_thread(struct btrfs_work *work)
 520 {
 521         struct btrfs_block_group_cache *block_group;
 522         struct btrfs_fs_info *fs_info;
 523         struct btrfs_caching_control *caching_ctl;
 524         int ret;
 525
 526         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 527         block_group = caching_ctl->block_group;
 528         fs_info = block_group->fs_info;
 529
 530         mutex_lock(&caching_ctl->mutex);
 531         down_read(&fs_info->commit_root_sem);
 532
 533         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 534                 ret = load_free_space_tree(caching_ctl);
 535         else
 536                 ret = load_extent_tree_free(caching_ctl);
 537
 538         spin_lock(&block_group->lock);
 539         block_group->caching_ctl = NULL;
 540         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 541         spin_unlock(&block_group->lock);
 542
 543 #ifdef CONFIG_BTRFS_DEBUG
 544         if (btrfs_should_fragment_free_space(block_group)) {
 545                 u64 bytes_used;
 546
 547                 spin_lock(&block_group->space_info->lock);
 548                 spin_lock(&block_group->lock);
 549                 bytes_used = block_group->key.offset -
 550                         btrfs_block_group_used(&block_group->item);
 551                 block_group->space_info->bytes_used += bytes_used >> 1;
 552                 spin_unlock(&block_group->lock);
 553                 spin_unlock(&block_group->space_info->lock);
 554                 fragment_free_space(block_group);
 555         }
 556 #endif
 557
 558         caching_ctl->progress = (u64)-1;
 559
 560         up_read(&fs_info->commit_root_sem);
 561         free_excluded_extents(fs_info, block_group);
 562         mutex_unlock(&caching_ctl->mutex);
 563
 564         wake_up(&caching_ctl->wait);
 565
 566         put_caching_control(caching_ctl);
 567         btrfs_put_block_group(block_group);
 568 }
 569
 570 static int cache_block_group(struct btrfs_block_group_cache *cache,
 571                              int load_cache_only)
 572 {
 573         DEFINE_WAIT(wait);
 574         struct btrfs_fs_info *fs_info = cache->fs_info;
 575         struct btrfs_caching_control *caching_ctl;
 576         int ret = 0;
 577
 578         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 579         if (!caching_ctl)
 580                 return -ENOMEM;
 581
 582         INIT_LIST_HEAD(&caching_ctl->list);
 583         mutex_init(&caching_ctl->mutex);
 584         init_waitqueue_head(&caching_ctl->wait);
 585         caching_ctl->block_group = cache;
 586         caching_ctl->progress = cache->key.objectid;
 587         refcount_set(&caching_ctl->count, 1);
 588         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 589                         caching_thread, NULL, NULL);
 590
 591         spin_lock(&cache->lock);
 592         /*
 593          * This should be a rare occasion, but this could happen I think in the
 594          * case where one thread starts to load the space cache info, and then
 595          * some other thread starts a transaction commit which tries to do an
 596          * allocation while the other thread is still loading the space cache
 597          * info.  The previous loop should have kept us from choosing this block
 598          * group, but if we've moved to the state where we will wait on caching
 599          * block groups we need to first check if we're doing a fast load here,
 600          * so we can wait for it to finish, otherwise we could end up allocating
 601          * from a block group who's cache gets evicted for one reason or
 602          * another.
 603          */
 604         while (cache->cached == BTRFS_CACHE_FAST) {
 605                 struct btrfs_caching_control *ctl;
 606
 607                 ctl = cache->caching_ctl;
 608                 refcount_inc(&ctl->count);
 609                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 610                 spin_unlock(&cache->lock);
 611
 612                 schedule();
 613
 614                 finish_wait(&ctl->wait, &wait);
 615                 put_caching_control(ctl);
 616                 spin_lock(&cache->lock);
 617         }
 618
 619         if (cache->cached != BTRFS_CACHE_NO) {
 620                 spin_unlock(&cache->lock);
 621                 kfree(caching_ctl);
 622                 return 0;
 623         }
 624         WARN_ON(cache->caching_ctl);
 625         cache->caching_ctl = caching_ctl;
 626         cache->cached = BTRFS_CACHE_FAST;
 627         spin_unlock(&cache->lock);
 628
 629         if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
 630                 mutex_lock(&caching_ctl->mutex);
 631                 ret = load_free_space_cache(fs_info, cache);
 632
 633                 spin_lock(&cache->lock);
 634                 if (ret == 1) {
 635                         cache->caching_ctl = NULL;
 636                         cache->cached = BTRFS_CACHE_FINISHED;
 637                         cache->last_byte_to_unpin = (u64)-1;
 638                         caching_ctl->progress = (u64)-1;
 639                 } else {
 640                         if (load_cache_only) {
 641                                 cache->caching_ctl = NULL;
 642                                 cache->cached = BTRFS_CACHE_NO;
 643                         } else {
 644                                 cache->cached = BTRFS_CACHE_STARTED;
 645                                 cache->has_caching_ctl = 1;
 646                         }
 647                 }
 648                 spin_unlock(&cache->lock);
 649 #ifdef CONFIG_BTRFS_DEBUG
 650                 if (ret == 1 &&
 651                     btrfs_should_fragment_free_space(cache)) {
 652                         u64 bytes_used;
 653
 654                         spin_lock(&cache->space_info->lock);
 655                         spin_lock(&cache->lock);
 656                         bytes_used = cache->key.offset -
 657                                 btrfs_block_group_used(&cache->item);
 658                         cache->space_info->bytes_used += bytes_used >> 1;
 659                         spin_unlock(&cache->lock);
 660                         spin_unlock(&cache->space_info->lock);
 661                         fragment_free_space(cache);
 662                 }
 663 #endif
 664                 mutex_unlock(&caching_ctl->mutex);
 665
 666                 wake_up(&caching_ctl->wait);
 667                 if (ret == 1) {
 668                         put_caching_control(caching_ctl);
 669                         free_excluded_extents(fs_info, cache);
 670                         return 0;
 671                 }
 672         } else {
 673                 /*
 674                  * We're either using the free space tree or no caching at all.
 675                  * Set cached to the appropriate value and wakeup any waiters.
 676                  */
 677                 spin_lock(&cache->lock);
 678                 if (load_cache_only) {
 679                         cache->caching_ctl = NULL;
 680                         cache->cached = BTRFS_CACHE_NO;
 681                 } else {
 682                         cache->cached = BTRFS_CACHE_STARTED;
 683                         cache->has_caching_ctl = 1;
 684                 }
 685                 spin_unlock(&cache->lock);
 686                 wake_up(&caching_ctl->wait);
 687         }
 688
 689         if (load_cache_only) {
 690                 put_caching_control(caching_ctl);
 691                 return 0;
 692         }
 693
 694         down_write(&fs_info->commit_root_sem);
 695         refcount_inc(&caching_ctl->count);
 696         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 697         up_write(&fs_info->commit_root_sem);
 698
 699         btrfs_get_block_group(cache);
 700
 701         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 702
 703         return ret;
 704 }
 705
 706 /*
 707  * return the block group that starts at or after bytenr
 708  */
 709 static struct btrfs_block_group_cache *
 710 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 711 {
 712         return block_group_cache_tree_search(info, bytenr, 0);
 713 }
 714
 715 /*
 716  * return the block group that contains the given bytenr
 717  */
 718 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 719                                                  struct btrfs_fs_info *info,
 720                                                  u64 bytenr)
 721 {
 722         return block_group_cache_tree_search(info, bytenr, 1);
 723 }
 724
 725 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 726                                                   u64 flags)
 727 {
 728         struct list_head *head = &info->space_info;
 729         struct btrfs_space_info *found;
 730
 731         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 732
 733         rcu_read_lock();
 734         list_for_each_entry_rcu(found, head, list) {
 735                 if (found->flags & flags) {
 736                         rcu_read_unlock();
 737                         return found;
 738                 }
 739         }
 740         rcu_read_unlock();
 741         return NULL;
 742 }
 743
 744 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, s64 num_bytes,
 745                              bool metadata, u64 root_objectid)
 746 {
 747         struct btrfs_space_info *space_info;
 748         u64 flags;
 749
 750         if (metadata) {
 751                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
 752                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
 753                 else
 754                         flags = BTRFS_BLOCK_GROUP_METADATA;
 755         } else {
 756                 flags = BTRFS_BLOCK_GROUP_DATA;
 757         }
 758
 759         space_info = __find_space_info(fs_info, flags);
 760         ASSERT(space_info);
 761         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
 762 }
 763
 764 /*
 765  * after adding space to the filesystem, we need to clear the full flags
 766  * on all the space infos.
 767  */
 768 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 769 {
 770         struct list_head *head = &info->space_info;
 771         struct btrfs_space_info *found;
 772
 773         rcu_read_lock();
 774         list_for_each_entry_rcu(found, head, list)
 775                 found->full = 0;
 776         rcu_read_unlock();
 777 }
 778
 779 /* simple helper to search for an existing data extent at a given offset */
 780 int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
 781 {
 782         int ret;
 783         struct btrfs_key key;
 784         struct btrfs_path *path;
 785
 786         path = btrfs_alloc_path();
 787         if (!path)
 788                 return -ENOMEM;
 789
 790         key.objectid = start;
 791         key.offset = len;
 792         key.type = BTRFS_EXTENT_ITEM_KEY;
 793         ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 794         btrfs_free_path(path);
 795         return ret;
 796 }
 797
 798 /*
 799  * helper function to lookup reference count and flags of a tree block.
 800  *
 801  * the head node for delayed ref is used to store the sum of all the
 802  * reference count modifications queued up in the rbtree. the head
 803  * node may also store the extent flags to set. This way you can check
 804  * to see what the reference count and extent flags would be if all of
 805  * the delayed refs are not processed.
 806  */
 807 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 808                              struct btrfs_fs_info *fs_info, u64 bytenr,
 809                              u64 offset, int metadata, u64 *refs, u64 *flags)
 810 {
 811         struct btrfs_delayed_ref_head *head;
 812         struct btrfs_delayed_ref_root *delayed_refs;
 813         struct btrfs_path *path;
 814         struct btrfs_extent_item *ei;
 815         struct extent_buffer *leaf;
 816         struct btrfs_key key;
 817         u32 item_size;
 818         u64 num_refs;
 819         u64 extent_flags;
 820         int ret;
 821
 822         /*
 823          * If we don't have skinny metadata, don't bother doing anything
 824          * different
 825          */
 826         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 827                 offset = fs_info->nodesize;
 828                 metadata = 0;
 829         }
 830
 831         path = btrfs_alloc_path();
 832         if (!path)
 833                 return -ENOMEM;
 834
 835         if (!trans) {
 836                 path->skip_locking = 1;
 837                 path->search_commit_root = 1;
 838         }
 839
 840 search_again:
 841         key.objectid = bytenr;
 842         key.offset = offset;
 843         if (metadata)
 844                 key.type = BTRFS_METADATA_ITEM_KEY;
 845         else
 846                 key.type = BTRFS_EXTENT_ITEM_KEY;
 847
 848         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 849         if (ret < 0)
 850                 goto out_free;
 851
 852         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 853                 if (path->slots[0]) {
 854                         path->slots[0]--;
 855                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 856                                               path->slots[0]);
 857                         if (key.objectid == bytenr &&
 858                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 859                             key.offset == fs_info->nodesize)
 860                                 ret = 0;
 861                 }
 862         }
 863
 864         if (ret == 0) {
 865                 leaf = path->nodes[0];
 866                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 867                 if (item_size >= sizeof(*ei)) {
 868                         ei = btrfs_item_ptr(leaf, path->slots[0],
 869                                             struct btrfs_extent_item);
 870                         num_refs = btrfs_extent_refs(leaf, ei);
 871                         extent_flags = btrfs_extent_flags(leaf, ei);
 872                 } else {
 873 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 874                         struct btrfs_extent_item_v0 *ei0;
 875                         BUG_ON(item_size != sizeof(*ei0));
 876                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 877                                              struct btrfs_extent_item_v0);
 878                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 879                         /* FIXME: this isn't correct for data */
 880                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 881 #else
 882                         BUG();
 883 #endif
 884                 }
 885                 BUG_ON(num_refs == 0);
 886         } else {
 887                 num_refs = 0;
 888                 extent_flags = 0;
 889                 ret = 0;
 890         }
 891
 892         if (!trans)
 893                 goto out;
 894
 895         delayed_refs = &trans->transaction->delayed_refs;
 896         spin_lock(&delayed_refs->lock);
 897         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 898         if (head) {
 899                 if (!mutex_trylock(&head->mutex)) {
 900                         refcount_inc(&head->refs);
 901                         spin_unlock(&delayed_refs->lock);
 902
 903                         btrfs_release_path(path);
 904
 905                         /*
 906                          * Mutex was contended, block until it's released and try
 907                          * again
 908                          */
 909                         mutex_lock(&head->mutex);
 910                         mutex_unlock(&head->mutex);
 911                         btrfs_put_delayed_ref_head(head);
 912                         goto search_again;
 913                 }
 914                 spin_lock(&head->lock);
 915                 if (head->extent_op && head->extent_op->update_flags)
 916                         extent_flags |= head->extent_op->flags_to_set;
 917                 else
 918                         BUG_ON(num_refs == 0);
 919
 920                 num_refs += head->ref_mod;
 921                 spin_unlock(&head->lock);
 922                 mutex_unlock(&head->mutex);
 923         }
 924         spin_unlock(&delayed_refs->lock);
 925 out:
 926         WARN_ON(num_refs == 0);
 927         if (refs)
 928                 *refs = num_refs;
 929         if (flags)
 930                 *flags = extent_flags;
 931 out_free:
 932         btrfs_free_path(path);
 933         return ret;
 934 }
 935
 936 /*
 937  * Back reference rules.  Back refs have three main goals:
 938  *
 939  * 1) differentiate between all holders of references to an extent so that
 940  *    when a reference is dropped we can make sure it was a valid reference
 941  *    before freeing the extent.
 942  *
 943  * 2) Provide enough information to quickly find the holders of an extent
 944  *    if we notice a given block is corrupted or bad.
 945  *
 946  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 947  *    maintenance.  This is actually the same as #2, but with a slightly
 948  *    different use case.
 949  *
 950  * There are two kinds of back refs. The implicit back refs is optimized
 951  * for pointers in non-shared tree blocks. For a given pointer in a block,
 952  * back refs of this kind provide information about the block's owner tree
 953  * and the pointer's key. These information allow us to find the block by
 954  * b-tree searching. The full back refs is for pointers in tree blocks not
 955  * referenced by their owner trees. The location of tree block is recorded
 956  * in the back refs. Actually the full back refs is generic, and can be
 957  * used in all cases the implicit back refs is used. The major shortcoming
 958  * of the full back refs is its overhead. Every time a tree block gets
 959  * COWed, we have to update back refs entry for all pointers in it.
 960  *
 961  * For a newly allocated tree block, we use implicit back refs for
 962  * pointers in it. This means most tree related operations only involve
 963  * implicit back refs. For a tree block created in old transaction, the
 964  * only way to drop a reference to it is COW it. So we can detect the
 965  * event that tree block loses its owner tree's reference and do the
 966  * back refs conversion.
 967  *
 968  * When a tree block is COWed through a tree, there are four cases:
 969  *
 970  * The reference count of the block is one and the tree is the block's
 971  * owner tree. Nothing to do in this case.
 972  *
 973  * The reference count of the block is one and the tree is not the
 974  * block's owner tree. In this case, full back refs is used for pointers
 975  * in the block. Remove these full back refs, add implicit back refs for
 976  * every pointers in the new block.
 977  *
 978  * The reference count of the block is greater than one and the tree is
 979  * the block's owner tree. In this case, implicit back refs is used for
 980  * pointers in the block. Add full back refs for every pointers in the
 981  * block, increase lower level extents' reference counts. The original
 982  * implicit back refs are entailed to the new block.
 983  *
 984  * The reference count of the block is greater than one and the tree is
 985  * not the block's owner tree. Add implicit back refs for every pointer in
 986  * the new block, increase lower level extents' reference count.
 987  *
 988  * Back Reference Key composing:
 989  *
 990  * The key objectid corresponds to the first byte in the extent,
 991  * The key type is used to differentiate between types of back refs.
 992  * There are different meanings of the key offset for different types
 993  * of back refs.
 994  *
 995  * File extents can be referenced by:
 996  *
 997  * - multiple snapshots, subvolumes, or different generations in one subvol
 998  * - different files inside a single subvolume
 999  * - different offsets inside a file (bookend extents in file.c)
1000  *
1001  * The extent ref structure for the implicit back refs has fields for:
1002  *
1003  * - Objectid of the subvolume root
1004  * - objectid of the file holding the reference
1005  * - original offset in the file
1006  * - how many bookend extents
1007  *
1008  * The key offset for the implicit back refs is hash of the first
1009  * three fields.
1010  *
1011  * The extent ref structure for the full back refs has field for:
1012  *
1013  * - number of pointers in the tree leaf
1014  *
1015  * The key offset for the implicit back refs is the first byte of
1016  * the tree leaf
1017  *
1018  * When a file extent is allocated, The implicit back refs is used.
1019  * the fields are filled in:
1020  *
1021  *     (root_key.objectid, inode objectid, offset in file, 1)
1022  *
1023  * When a file extent is removed file truncation, we find the
1024  * corresponding implicit back refs and check the following fields:
1025  *
1026  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1027  *
1028  * Btree extents can be referenced by:
1029  *
1030  * - Different subvolumes
1031  *
1032  * Both the implicit back refs and the full back refs for tree blocks
1033  * only consist of key. The key offset for the implicit back refs is
1034  * objectid of block's owner tree. The key offset for the full back refs
1035  * is the first byte of parent block.
1036  *
1037  * When implicit back refs is used, information about the lowest key and
1038  * level of the tree block are required. These information are stored in
1039  * tree block info structure.
1040  */
1041
1042 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1043 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1044                                   struct btrfs_fs_info *fs_info,
1045                                   struct btrfs_path *path,
1046                                   u64 owner, u32 extra_size)
1047 {
1048         struct btrfs_root *root = fs_info->extent_root;
1049         struct btrfs_extent_item *item;
1050         struct btrfs_extent_item_v0 *ei0;
1051         struct btrfs_extent_ref_v0 *ref0;
1052         struct btrfs_tree_block_info *bi;
1053         struct extent_buffer *leaf;
1054         struct btrfs_key key;
1055         struct btrfs_key found_key;
1056         u32 new_size = sizeof(*item);
1057         u64 refs;
1058         int ret;
1059
1060         leaf = path->nodes[0];
1061         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1062
1063         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1064         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1065                              struct btrfs_extent_item_v0);
1066         refs = btrfs_extent_refs_v0(leaf, ei0);
1067
1068         if (owner == (u64)-1) {
1069                 while (1) {
1070                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1071                                 ret = btrfs_next_leaf(root, path);
1072                                 if (ret < 0)
1073                                         return ret;
1074                                 BUG_ON(ret > 0); /* Corruption */
1075                                 leaf = path->nodes[0];
1076                         }
1077                         btrfs_item_key_to_cpu(leaf, &found_key,
1078                                               path->slots[0]);
1079                         BUG_ON(key.objectid != found_key.objectid);
1080                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1081                                 path->slots[0]++;
1082                                 continue;
1083                         }
1084                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1085                                               struct btrfs_extent_ref_v0);
1086                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1087                         break;
1088                 }
1089         }
1090         btrfs_release_path(path);
1091
1092         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1093                 new_size += sizeof(*bi);
1094
1095         new_size -= sizeof(*ei0);
1096         ret = btrfs_search_slot(trans, root, &key, path,
1097                                 new_size + extra_size, 1);
1098         if (ret < 0)
1099                 return ret;
1100         BUG_ON(ret); /* Corruption */
1101
1102         btrfs_extend_item(fs_info, path, new_size);
1103
1104         leaf = path->nodes[0];
1105         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1106         btrfs_set_extent_refs(leaf, item, refs);
1107         /* FIXME: get real generation */
1108         btrfs_set_extent_generation(leaf, item, 0);
1109         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1110                 btrfs_set_extent_flags(leaf, item,
1111                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1112                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1113                 bi = (struct btrfs_tree_block_info *)(item + 1);
1114                 /* FIXME: get first key of the block */
1115                 memzero_extent_buffer(leaf, (unsigned long)bi, sizeof(*bi));
1116                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1117         } else {
1118                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1119         }
1120         btrfs_mark_buffer_dirty(leaf);
1121         return 0;
1122 }
1123 #endif
1124
1125 /*
1126  * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
1127  * is_data == BTRFS_REF_TYPE_DATA, data type is requried,
1128  * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
1129  */
1130 int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
1131                                      struct btrfs_extent_inline_ref *iref,
1132                                      enum btrfs_inline_ref_type is_data)
1133 {
1134         int type = btrfs_extent_inline_ref_type(eb, iref);
1135         u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
1136
1137         if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1138             type == BTRFS_SHARED_BLOCK_REF_KEY ||
1139             type == BTRFS_SHARED_DATA_REF_KEY ||
1140             type == BTRFS_EXTENT_DATA_REF_KEY) {
1141                 if (is_data == BTRFS_REF_TYPE_BLOCK) {
1142                         if (type == BTRFS_TREE_BLOCK_REF_KEY)
1143                                 return type;
1144                         if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1145                                 ASSERT(eb->fs_info);
1146                                 /*
1147                                  * Every shared one has parent tree
1148                                  * block, which must be aligned to
1149                                  * nodesize.
1150                                  */
1151                                 if (offset &&
1152                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1153                                         return type;
1154                         }
1155                 } else if (is_data == BTRFS_REF_TYPE_DATA) {
1156                         if (type == BTRFS_EXTENT_DATA_REF_KEY)
1157                                 return type;
1158                         if (type == BTRFS_SHARED_DATA_REF_KEY) {
1159                                 ASSERT(eb->fs_info);
1160                                 /*
1161                                  * Every shared one has parent tree
1162                                  * block, which must be aligned to
1163                                  * nodesize.
1164                                  */
1165                                 if (offset &&
1166                                     IS_ALIGNED(offset, eb->fs_info->nodesize))
1167                                         return type;
1168                         }
1169                 } else {
1170                         ASSERT(is_data == BTRFS_REF_TYPE_ANY);
1171                         return type;
1172                 }
1173         }
1174
1175         btrfs_print_leaf((struct extent_buffer *)eb);
1176         btrfs_err(eb->fs_info, "eb %llu invalid extent inline ref type %d",
1177                   eb->start, type);
1178         WARN_ON(1);
1179
1180         return BTRFS_REF_TYPE_INVALID;
1181 }
1182
1183 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1184 {
1185         u32 high_crc = ~(u32)0;
1186         u32 low_crc = ~(u32)0;
1187         __le64 lenum;
1188
1189         lenum = cpu_to_le64(root_objectid);
1190         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1191         lenum = cpu_to_le64(owner);
1192         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1193         lenum = cpu_to_le64(offset);
1194         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1195
1196         return ((u64)high_crc << 31) ^ (u64)low_crc;
1197 }
1198
1199 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1200                                      struct btrfs_extent_data_ref *ref)
1201 {
1202         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1203                                     btrfs_extent_data_ref_objectid(leaf, ref),
1204                                     btrfs_extent_data_ref_offset(leaf, ref));
1205 }
1206
1207 static int match_extent_data_ref(struct extent_buffer *leaf,
1208                                  struct btrfs_extent_data_ref *ref,
1209                                  u64 root_objectid, u64 owner, u64 offset)
1210 {
1211         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1212             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1213             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1214                 return 0;
1215         return 1;
1216 }
1217
1218 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1219                                            struct btrfs_fs_info *fs_info,
1220                                            struct btrfs_path *path,
1221                                            u64 bytenr, u64 parent,
1222                                            u64 root_objectid,
1223                                            u64 owner, u64 offset)
1224 {
1225         struct btrfs_root *root = fs_info->extent_root;
1226         struct btrfs_key key;
1227         struct btrfs_extent_data_ref *ref;
1228         struct extent_buffer *leaf;
1229         u32 nritems;
1230         int ret;
1231         int recow;
1232         int err = -ENOENT;
1233
1234         key.objectid = bytenr;
1235         if (parent) {
1236                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1237                 key.offset = parent;
1238         } else {
1239                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1240                 key.offset = hash_extent_data_ref(root_objectid,
1241                                                   owner, offset);
1242         }
1243 again:
1244         recow = 0;
1245         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1246         if (ret < 0) {
1247                 err = ret;
1248                 goto fail;
1249         }
1250
1251         if (parent) {
1252                 if (!ret)
1253                         return 0;
1254 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1255                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1256                 btrfs_release_path(path);
1257                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1258                 if (ret < 0) {
1259                         err = ret;
1260                         goto fail;
1261                 }
1262                 if (!ret)
1263                         return 0;
1264 #endif
1265                 goto fail;
1266         }
1267
1268         leaf = path->nodes[0];
1269         nritems = btrfs_header_nritems(leaf);
1270         while (1) {
1271                 if (path->slots[0] >= nritems) {
1272                         ret = btrfs_next_leaf(root, path);
1273                         if (ret < 0)
1274                                 err = ret;
1275                         if (ret)
1276                                 goto fail;
1277
1278                         leaf = path->nodes[0];
1279                         nritems = btrfs_header_nritems(leaf);
1280                         recow = 1;
1281                 }
1282
1283                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1284                 if (key.objectid != bytenr ||
1285                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1286                         goto fail;
1287
1288                 ref = btrfs_item_ptr(leaf, path->slots[0],
1289                                      struct btrfs_extent_data_ref);
1290
1291                 if (match_extent_data_ref(leaf, ref, root_objectid,
1292                                           owner, offset)) {
1293                         if (recow) {
1294                                 btrfs_release_path(path);
1295                                 goto again;
1296                         }
1297                         err = 0;
1298                         break;
1299                 }
1300                 path->slots[0]++;
1301         }
1302 fail:
1303         return err;
1304 }
1305
1306 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1307                                            struct btrfs_fs_info *fs_info,
1308                                            struct btrfs_path *path,
1309                                            u64 bytenr, u64 parent,
1310                                            u64 root_objectid, u64 owner,
1311                                            u64 offset, int refs_to_add)
1312 {
1313         struct btrfs_root *root = fs_info->extent_root;
1314         struct btrfs_key key;
1315         struct extent_buffer *leaf;
1316         u32 size;
1317         u32 num_refs;
1318         int ret;
1319
1320         key.objectid = bytenr;
1321         if (parent) {
1322                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1323                 key.offset = parent;
1324                 size = sizeof(struct btrfs_shared_data_ref);
1325         } else {
1326                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1327                 key.offset = hash_extent_data_ref(root_objectid,
1328                                                   owner, offset);
1329                 size = sizeof(struct btrfs_extent_data_ref);
1330         }
1331
1332         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1333         if (ret && ret != -EEXIST)
1334                 goto fail;
1335
1336         leaf = path->nodes[0];
1337         if (parent) {
1338                 struct btrfs_shared_data_ref *ref;
1339                 ref = btrfs_item_ptr(leaf, path->slots[0],
1340                                      struct btrfs_shared_data_ref);
1341                 if (ret == 0) {
1342                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1343                 } else {
1344                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1345                         num_refs += refs_to_add;
1346                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1347                 }
1348         } else {
1349                 struct btrfs_extent_data_ref *ref;
1350                 while (ret == -EEXIST) {
1351                         ref = btrfs_item_ptr(leaf, path->slots[0],
1352                                              struct btrfs_extent_data_ref);
1353                         if (match_extent_data_ref(leaf, ref, root_objectid,
1354                                                   owner, offset))
1355                                 break;
1356                         btrfs_release_path(path);
1357                         key.offset++;
1358                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1359                                                       size);
1360                         if (ret && ret != -EEXIST)
1361                                 goto fail;
1362
1363                         leaf = path->nodes[0];
1364                 }
1365                 ref = btrfs_item_ptr(leaf, path->slots[0],
1366                                      struct btrfs_extent_data_ref);
1367                 if (ret == 0) {
1368                         btrfs_set_extent_data_ref_root(leaf, ref,
1369                                                        root_objectid);
1370                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1371                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1372                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1373                 } else {
1374                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1375                         num_refs += refs_to_add;
1376                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1377                 }
1378         }
1379         btrfs_mark_buffer_dirty(leaf);
1380         ret = 0;
1381 fail:
1382         btrfs_release_path(path);
1383         return ret;
1384 }
1385
1386 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1387                                            struct btrfs_fs_info *fs_info,
1388                                            struct btrfs_path *path,
1389                                            int refs_to_drop, int *last_ref)
1390 {
1391         struct btrfs_key key;
1392         struct btrfs_extent_data_ref *ref1 = NULL;
1393         struct btrfs_shared_data_ref *ref2 = NULL;
1394         struct extent_buffer *leaf;
1395         u32 num_refs = 0;
1396         int ret = 0;
1397
1398         leaf = path->nodes[0];
1399         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1400
1401         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1402                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1403                                       struct btrfs_extent_data_ref);
1404                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1405         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1406                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1407                                       struct btrfs_shared_data_ref);
1408                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1409 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1410         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1411                 struct btrfs_extent_ref_v0 *ref0;
1412                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1413                                       struct btrfs_extent_ref_v0);
1414                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1415 #endif
1416         } else {
1417                 BUG();
1418         }
1419
1420         BUG_ON(num_refs < refs_to_drop);
1421         num_refs -= refs_to_drop;
1422
1423         if (num_refs == 0) {
1424                 ret = btrfs_del_item(trans, fs_info->extent_root, path);
1425                 *last_ref = 1;
1426         } else {
1427                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1428                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1429                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1430                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1431 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1432                 else {
1433                         struct btrfs_extent_ref_v0 *ref0;
1434                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1435                                         struct btrfs_extent_ref_v0);
1436                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1437                 }
1438 #endif
1439                 btrfs_mark_buffer_dirty(leaf);
1440         }
1441         return ret;
1442 }
1443
1444 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1445                                           struct btrfs_extent_inline_ref *iref)
1446 {
1447         struct btrfs_key key;
1448         struct extent_buffer *leaf;
1449         struct btrfs_extent_data_ref *ref1;
1450         struct btrfs_shared_data_ref *ref2;
1451         u32 num_refs = 0;
1452         int type;
1453
1454         leaf = path->nodes[0];
1455         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1456         if (iref) {
1457                 /*
1458                  * If type is invalid, we should have bailed out earlier than
1459                  * this call.
1460                  */
1461                 type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
1462                 ASSERT(type != BTRFS_REF_TYPE_INVALID);
1463                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1464                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1465                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1466                 } else {
1467                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1468                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1469                 }
1470         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1471                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1472                                       struct btrfs_extent_data_ref);
1473                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1474         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1475                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1476                                       struct btrfs_shared_data_ref);
1477                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1478 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1479         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1480                 struct btrfs_extent_ref_v0 *ref0;
1481                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1482                                       struct btrfs_extent_ref_v0);
1483                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1484 #endif
1485         } else {
1486                 WARN_ON(1);
1487         }
1488         return num_refs;
1489 }
1490
1491 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1492                                           struct btrfs_fs_info *fs_info,
1493                                           struct btrfs_path *path,
1494                                           u64 bytenr, u64 parent,
1495                                           u64 root_objectid)
1496 {
1497         struct btrfs_root *root = fs_info->extent_root;
1498         struct btrfs_key key;
1499         int ret;
1500
1501         key.objectid = bytenr;
1502         if (parent) {
1503                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1504                 key.offset = parent;
1505         } else {
1506                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1507                 key.offset = root_objectid;
1508         }
1509
1510         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1511         if (ret > 0)
1512                 ret = -ENOENT;
1513 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1514         if (ret == -ENOENT && parent) {
1515                 btrfs_release_path(path);
1516                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1517                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1518                 if (ret > 0)
1519                         ret = -ENOENT;
1520         }
1521 #endif
1522         return ret;
1523 }
1524
1525 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1526                                           struct btrfs_fs_info *fs_info,
1527                                           struct btrfs_path *path,
1528                                           u64 bytenr, u64 parent,
1529                                           u64 root_objectid)
1530 {
1531         struct btrfs_key key;
1532         int ret;
1533
1534         key.objectid = bytenr;
1535         if (parent) {
1536                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1537                 key.offset = parent;
1538         } else {
1539                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1540                 key.offset = root_objectid;
1541         }
1542
1543         ret = btrfs_insert_empty_item(trans, fs_info->extent_root,
1544                                       path, &key, 0);
1545         btrfs_release_path(path);
1546         return ret;
1547 }
1548
1549 static inline int extent_ref_type(u64 parent, u64 owner)
1550 {
1551         int type;
1552         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1553                 if (parent > 0)
1554                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1555                 else
1556                         type = BTRFS_TREE_BLOCK_REF_KEY;
1557         } else {
1558                 if (parent > 0)
1559                         type = BTRFS_SHARED_DATA_REF_KEY;
1560                 else
1561                         type = BTRFS_EXTENT_DATA_REF_KEY;
1562         }
1563         return type;
1564 }
1565
1566 static int find_next_key(struct btrfs_path *path, int level,
1567                          struct btrfs_key *key)
1568
1569 {
1570         for (; level < BTRFS_MAX_LEVEL; level++) {
1571                 if (!path->nodes[level])
1572                         break;
1573                 if (path->slots[level] + 1 >=
1574                     btrfs_header_nritems(path->nodes[level]))
1575                         continue;
1576                 if (level == 0)
1577                         btrfs_item_key_to_cpu(path->nodes[level], key,
1578                                               path->slots[level] + 1);
1579                 else
1580                         btrfs_node_key_to_cpu(path->nodes[level], key,
1581                                               path->slots[level] + 1);
1582                 return 0;
1583         }
1584         return 1;
1585 }
1586
1587 /*
1588  * look for inline back ref. if back ref is found, *ref_ret is set
1589  * to the address of inline back ref, and 0 is returned.
1590  *
1591  * if back ref isn't found, *ref_ret is set to the address where it
1592  * should be inserted, and -ENOENT is returned.
1593  *
1594  * if insert is true and there are too many inline back refs, the path
1595  * points to the extent item, and -EAGAIN is returned.
1596  *
1597  * NOTE: inline back refs are ordered in the same way that back ref
1598  *       items in the tree are ordered.
1599  */
1600 static noinline_for_stack
1601 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1602                                  struct btrfs_fs_info *fs_info,
1603                                  struct btrfs_path *path,
1604                                  struct btrfs_extent_inline_ref **ref_ret,
1605                                  u64 bytenr, u64 num_bytes,
1606                                  u64 parent, u64 root_objectid,
1607                                  u64 owner, u64 offset, int insert)
1608 {
1609         struct btrfs_root *root = fs_info->extent_root;
1610         struct btrfs_key key;
1611         struct extent_buffer *leaf;
1612         struct btrfs_extent_item *ei;
1613         struct btrfs_extent_inline_ref *iref;
1614         u64 flags;
1615         u64 item_size;
1616         unsigned long ptr;
1617         unsigned long end;
1618         int extra_size;
1619         int type;
1620         int want;
1621         int ret;
1622         int err = 0;
1623         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
1624         int needed;
1625
1626         key.objectid = bytenr;
1627         key.type = BTRFS_EXTENT_ITEM_KEY;
1628         key.offset = num_bytes;
1629
1630         want = extent_ref_type(parent, owner);
1631         if (insert) {
1632                 extra_size = btrfs_extent_inline_ref_size(want);
1633                 path->keep_locks = 1;
1634         } else
1635                 extra_size = -1;
1636
1637         /*
1638          * Owner is our parent level, so we can just add one to get the level
1639          * for the block we are interested in.
1640          */
1641         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1642                 key.type = BTRFS_METADATA_ITEM_KEY;
1643                 key.offset = owner;
1644         }
1645
1646 again:
1647         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1648         if (ret < 0) {
1649                 err = ret;
1650                 goto out;
1651         }
1652
1653         /*
1654          * We may be a newly converted file system which still has the old fat
1655          * extent entries for metadata, so try and see if we have one of those.
1656          */
1657         if (ret > 0 && skinny_metadata) {
1658                 skinny_metadata = false;
1659                 if (path->slots[0]) {
1660                         path->slots[0]--;
1661                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1662                                               path->slots[0]);
1663                         if (key.objectid == bytenr &&
1664                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1665                             key.offset == num_bytes)
1666                                 ret = 0;
1667                 }
1668                 if (ret) {
1669                         key.objectid = bytenr;
1670                         key.type = BTRFS_EXTENT_ITEM_KEY;
1671                         key.offset = num_bytes;
1672                         btrfs_release_path(path);
1673                         goto again;
1674                 }
1675         }
1676
1677         if (ret && !insert) {
1678                 err = -ENOENT;
1679                 goto out;
1680         } else if (WARN_ON(ret)) {
1681                 err = -EIO;
1682                 goto out;
1683         }
1684
1685         leaf = path->nodes[0];
1686         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1687 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1688         if (item_size < sizeof(*ei)) {
1689                 if (!insert) {
1690                         err = -ENOENT;
1691                         goto out;
1692                 }
1693                 ret = convert_extent_item_v0(trans, fs_info, path, owner,
1694                                              extra_size);
1695                 if (ret < 0) {
1696                         err = ret;
1697                         goto out;
1698                 }
1699                 leaf = path->nodes[0];
1700                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1701         }
1702 #endif
1703         BUG_ON(item_size < sizeof(*ei));
1704
1705         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1706         flags = btrfs_extent_flags(leaf, ei);
1707
1708         ptr = (unsigned long)(ei + 1);
1709         end = (unsigned long)ei + item_size;
1710
1711         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1712                 ptr += sizeof(struct btrfs_tree_block_info);
1713                 BUG_ON(ptr > end);
1714         }
1715
1716         if (owner >= BTRFS_FIRST_FREE_OBJECTID)
1717                 needed = BTRFS_REF_TYPE_DATA;
1718         else
1719                 needed = BTRFS_REF_TYPE_BLOCK;
1720
1721         err = -ENOENT;
1722         while (1) {
1723                 if (ptr >= end) {
1724                         WARN_ON(ptr > end);
1725                         break;
1726                 }
1727                 iref = (struct btrfs_extent_inline_ref *)ptr;
1728                 type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
1729                 if (type == BTRFS_REF_TYPE_INVALID) {
1730                         err = -EINVAL;
1731                         goto out;
1732                 }
1733
1734                 if (want < type)
1735                         break;
1736                 if (want > type) {
1737                         ptr += btrfs_extent_inline_ref_size(type);
1738                         continue;
1739                 }
1740
1741                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1742                         struct btrfs_extent_data_ref *dref;
1743                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1744                         if (match_extent_data_ref(leaf, dref, root_objectid,
1745                                                   owner, offset)) {
1746                                 err = 0;
1747                                 break;
1748                         }
1749                         if (hash_extent_data_ref_item(leaf, dref) <
1750                             hash_extent_data_ref(root_objectid, owner, offset))
1751                                 break;
1752                 } else {
1753                         u64 ref_offset;
1754                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1755                         if (parent > 0) {
1756                                 if (parent == ref_offset) {
1757                                         err = 0;
1758                                         break;
1759                                 }
1760                                 if (ref_offset < parent)
1761                                         break;
1762                         } else {
1763                                 if (root_objectid == ref_offset) {
1764                                         err = 0;
1765                                         break;
1766                                 }
1767                                 if (ref_offset < root_objectid)
1768                                         break;
1769                         }
1770                 }
1771                 ptr += btrfs_extent_inline_ref_size(type);
1772         }
1773         if (err == -ENOENT && insert) {
1774                 if (item_size + extra_size >=
1775                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1776                         err = -EAGAIN;
1777                         goto out;
1778                 }
1779                 /*
1780                  * To add new inline back ref, we have to make sure
1781                  * there is no corresponding back ref item.
1782                  * For simplicity, we just do not add new inline back
1783                  * ref if there is any kind of item for this block
1784                  */
1785                 if (find_next_key(path, 0, &key) == 0 &&
1786                     key.objectid == bytenr &&
1787                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1788                         err = -EAGAIN;
1789                         goto out;
1790                 }
1791         }
1792         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1793 out:
1794         if (insert) {
1795                 path->keep_locks = 0;
1796                 btrfs_unlock_up_safe(path, 1);
1797         }
1798         return err;
1799 }
1800
1801 /*
1802  * helper to add new inline back ref
1803  */
1804 static noinline_for_stack
1805 void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
1806                                  struct btrfs_path *path,
1807                                  struct btrfs_extent_inline_ref *iref,
1808                                  u64 parent, u64 root_objectid,
1809                                  u64 owner, u64 offset, int refs_to_add,
1810                                  struct btrfs_delayed_extent_op *extent_op)
1811 {
1812         struct extent_buffer *leaf;
1813         struct btrfs_extent_item *ei;
1814         unsigned long ptr;
1815         unsigned long end;
1816         unsigned long item_offset;
1817         u64 refs;
1818         int size;
1819         int type;
1820
1821         leaf = path->nodes[0];
1822         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1823         item_offset = (unsigned long)iref - (unsigned long)ei;
1824
1825         type = extent_ref_type(parent, owner);
1826         size = btrfs_extent_inline_ref_size(type);
1827
1828         btrfs_extend_item(fs_info, path, size);
1829
1830         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1831         refs = btrfs_extent_refs(leaf, ei);
1832         refs += refs_to_add;
1833         btrfs_set_extent_refs(leaf, ei, refs);
1834         if (extent_op)
1835                 __run_delayed_extent_op(extent_op, leaf, ei);
1836
1837         ptr = (unsigned long)ei + item_offset;
1838         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1839         if (ptr < end - size)
1840                 memmove_extent_buffer(leaf, ptr + size, ptr,
1841                                       end - size - ptr);
1842
1843         iref = (struct btrfs_extent_inline_ref *)ptr;
1844         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1845         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1846                 struct btrfs_extent_data_ref *dref;
1847                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1848                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1849                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1850                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1851                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1852         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1853                 struct btrfs_shared_data_ref *sref;
1854                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1855                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1856                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1857         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1858                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1859         } else {
1860                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1861         }
1862         btrfs_mark_buffer_dirty(leaf);
1863 }
1864
1865 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1866                                  struct btrfs_fs_info *fs_info,
1867                                  struct btrfs_path *path,
1868                                  struct btrfs_extent_inline_ref **ref_ret,
1869                                  u64 bytenr, u64 num_bytes, u64 parent,
1870                                  u64 root_objectid, u64 owner, u64 offset)
1871 {
1872         int ret;
1873
1874         ret = lookup_inline_extent_backref(trans, fs_info, path, ref_ret,
1875                                            bytenr, num_bytes, parent,
1876                                            root_objectid, owner, offset, 0);
1877         if (ret != -ENOENT)
1878                 return ret;
1879
1880         btrfs_release_path(path);
1881         *ref_ret = NULL;
1882
1883         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1884                 ret = lookup_tree_block_ref(trans, fs_info, path, bytenr,
1885                                             parent, root_objectid);
1886         } else {
1887                 ret = lookup_extent_data_ref(trans, fs_info, path, bytenr,
1888                                              parent, root_objectid, owner,
1889                                              offset);
1890         }
1891         return ret;
1892 }
1893
1894 /*
1895  * helper to update/remove inline back ref
1896  */
1897 static noinline_for_stack
1898 void update_inline_extent_backref(struct btrfs_fs_info *fs_info,
1899                                   struct btrfs_path *path,
1900                                   struct btrfs_extent_inline_ref *iref,
1901                                   int refs_to_mod,
1902                                   struct btrfs_delayed_extent_op *extent_op,
1903                                   int *last_ref)
1904 {
1905         struct extent_buffer *leaf;
1906         struct btrfs_extent_item *ei;
1907         struct btrfs_extent_data_ref *dref = NULL;
1908         struct btrfs_shared_data_ref *sref = NULL;
1909         unsigned long ptr;
1910         unsigned long end;
1911         u32 item_size;
1912         int size;
1913         int type;
1914         u64 refs;
1915
1916         leaf = path->nodes[0];
1917         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1918         refs = btrfs_extent_refs(leaf, ei);
1919         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1920         refs += refs_to_mod;
1921         btrfs_set_extent_refs(leaf, ei, refs);
1922         if (extent_op)
1923                 __run_delayed_extent_op(extent_op, leaf, ei);
1924
1925         /*
1926          * If type is invalid, we should have bailed out after
1927          * lookup_inline_extent_backref().
1928          */
1929         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1930         ASSERT(type != BTRFS_REF_TYPE_INVALID);
1931
1932         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1933                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1934                 refs = btrfs_extent_data_ref_count(leaf, dref);
1935         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1936                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1937                 refs = btrfs_shared_data_ref_count(leaf, sref);
1938         } else {
1939                 refs = 1;
1940                 BUG_ON(refs_to_mod != -1);
1941         }
1942
1943         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1944         refs += refs_to_mod;
1945
1946         if (refs > 0) {
1947                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1948                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1949                 else
1950                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1951         } else {
1952                 *last_ref = 1;
1953                 size =  btrfs_extent_inline_ref_size(type);
1954                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1955                 ptr = (unsigned long)iref;
1956                 end = (unsigned long)ei + item_size;
1957                 if (ptr + size < end)
1958                         memmove_extent_buffer(leaf, ptr, ptr + size,
1959                                               end - ptr - size);
1960                 item_size -= size;
1961                 btrfs_truncate_item(fs_info, path, item_size, 1);
1962         }
1963         btrfs_mark_buffer_dirty(leaf);
1964 }
1965
1966 static noinline_for_stack
1967 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1968                                  struct btrfs_fs_info *fs_info,
1969                                  struct btrfs_path *path,
1970                                  u64 bytenr, u64 num_bytes, u64 parent,
1971                                  u64 root_objectid, u64 owner,
1972                                  u64 offset, int refs_to_add,
1973                                  struct btrfs_delayed_extent_op *extent_op)
1974 {
1975         struct btrfs_extent_inline_ref *iref;
1976         int ret;
1977
1978         ret = lookup_inline_extent_backref(trans, fs_info, path, &iref,
1979                                            bytenr, num_bytes, parent,
1980                                            root_objectid, owner, offset, 1);
1981         if (ret == 0) {
1982                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1983                 update_inline_extent_backref(fs_info, path, iref,
1984                                              refs_to_add, extent_op, NULL);
1985         } else if (ret == -ENOENT) {
1986                 setup_inline_extent_backref(fs_info, path, iref, parent,
1987                                             root_objectid, owner, offset,
1988                                             refs_to_add, extent_op);
1989                 ret = 0;
1990         }
1991         return ret;
1992 }
1993
1994 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1995                                  struct btrfs_fs_info *fs_info,
1996                                  struct btrfs_path *path,
1997                                  u64 bytenr, u64 parent, u64 root_objectid,
1998                                  u64 owner, u64 offset, int refs_to_add)
1999 {
2000         int ret;
2001         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2002                 BUG_ON(refs_to_add != 1);
2003                 ret = insert_tree_block_ref(trans, fs_info, path, bytenr,
2004                                             parent, root_objectid);
2005         } else {
2006                 ret = insert_extent_data_ref(trans, fs_info, path, bytenr,
2007                                              parent, root_objectid,
2008                                              owner, offset, refs_to_add);
2009         }
2010         return ret;
2011 }
2012
2013 static int remove_extent_backref(struct btrfs_trans_handle *trans,
2014                                  struct btrfs_fs_info *fs_info,
2015                                  struct btrfs_path *path,
2016                                  struct btrfs_extent_inline_ref *iref,
2017                                  int refs_to_drop, int is_data, int *last_ref)
2018 {
2019         int ret = 0;
2020
2021         BUG_ON(!is_data && refs_to_drop != 1);
2022         if (iref) {
2023                 update_inline_extent_backref(fs_info, path, iref,
2024                                              -refs_to_drop, NULL, last_ref);
2025         } else if (is_data) {
2026                 ret = remove_extent_data_ref(trans, fs_info, path, refs_to_drop,
2027                                              last_ref);
2028         } else {
2029                 *last_ref = 1;
2030                 ret = btrfs_del_item(trans, fs_info->extent_root, path);
2031         }
2032         return ret;
2033 }
2034
2035 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
2036 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
2037                                u64 *discarded_bytes)
2038 {
2039         int j, ret = 0;
2040         u64 bytes_left, end;
2041         u64 aligned_start = ALIGN(start, 1 << 9);
2042
2043         if (WARN_ON(start != aligned_start)) {
2044                 len -= aligned_start - start;
2045                 len = round_down(len, 1 << 9);
2046                 start = aligned_start;
2047         }
2048
2049         *discarded_bytes = 0;
2050
2051         if (!len)
2052                 return 0;
2053
2054         end = start + len;
2055         bytes_left = len;
2056
2057         /* Skip any superblocks on this device. */
2058         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
2059                 u64 sb_start = btrfs_sb_offset(j);
2060                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
2061                 u64 size = sb_start - start;
2062
2063                 if (!in_range(sb_start, start, bytes_left) &&
2064                     !in_range(sb_end, start, bytes_left) &&
2065                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
2066                         continue;
2067
2068                 /*
2069                  * Superblock spans beginning of range.  Adjust start and
2070                  * try again.
2071                  */
2072                 if (sb_start <= start) {
2073                         start += sb_end - start;
2074                         if (start > end) {
2075                                 bytes_left = 0;
2076                                 break;
2077                         }
2078                         bytes_left = end - start;
2079                         continue;
2080                 }
2081
2082                 if (size) {
2083                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2084                                                    GFP_NOFS, 0);
2085                         if (!ret)
2086                                 *discarded_bytes += size;
2087                         else if (ret != -EOPNOTSUPP)
2088                                 return ret;
2089                 }
2090
2091                 start = sb_end;
2092                 if (start > end) {
2093                         bytes_left = 0;
2094                         break;
2095                 }
2096                 bytes_left = end - start;
2097         }
2098
2099         if (bytes_left) {
2100                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2101                                            GFP_NOFS, 0);
2102                 if (!ret)
2103                         *discarded_bytes += bytes_left;
2104         }
2105         return ret;
2106 }
2107
2108 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
2109                          u64 num_bytes, u64 *actual_bytes)
2110 {
2111         int ret;
2112         u64 discarded_bytes = 0;
2113         struct btrfs_bio *bbio = NULL;
2114
2115
2116         /*
2117          * Avoid races with device replace and make sure our bbio has devices
2118          * associated to its stripes that don't go away while we are discarding.
2119          */
2120         btrfs_bio_counter_inc_blocked(fs_info);
2121         /* Tell the block device(s) that the sectors can be discarded */
2122         ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
2123                               &bbio, 0);
2124         /* Error condition is -ENOMEM */
2125         if (!ret) {
2126                 struct btrfs_bio_stripe *stripe = bbio->stripes;
2127                 int i;
2128
2129
2130                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2131                         u64 bytes;
2132                         struct request_queue *req_q;
2133
2134                         if (!stripe->dev->bdev) {
2135                                 ASSERT(btrfs_test_opt(fs_info, DEGRADED));
2136                                 continue;
2137                         }
2138                         req_q = bdev_get_queue(stripe->dev->bdev);
2139                         if (!blk_queue_discard(req_q))
2140                                 continue;
2141
2142                         ret = btrfs_issue_discard(stripe->dev->bdev,
2143                                                   stripe->physical,
2144                                                   stripe->length,
2145                                                   &bytes);
2146                         if (!ret)
2147                                 discarded_bytes += bytes;
2148                         else if (ret != -EOPNOTSUPP)
2149                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2150
2151                         /*
2152                          * Just in case we get back EOPNOTSUPP for some reason,
2153                          * just ignore the return value so we don't screw up
2154                          * people calling discard_extent.
2155                          */
2156                         ret = 0;
2157                 }
2158                 btrfs_put_bbio(bbio);
2159         }
2160         btrfs_bio_counter_dec(fs_info);
2161
2162         if (actual_bytes)
2163                 *actual_bytes = discarded_bytes;
2164
2165
2166         if (ret == -EOPNOTSUPP)
2167                 ret = 0;
2168         return ret;
2169 }
2170
2171 /* Can return -ENOMEM */
2172 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2173                          struct btrfs_root *root,
2174                          u64 bytenr, u64 num_bytes, u64 parent,
2175                          u64 root_objectid, u64 owner, u64 offset)
2176 {
2177         struct btrfs_fs_info *fs_info = root->fs_info;
2178         int old_ref_mod, new_ref_mod;
2179         int ret;
2180
2181         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2182                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2183
2184         btrfs_ref_tree_mod(root, bytenr, num_bytes, parent, root_objectid,
2185                            owner, offset, BTRFS_ADD_DELAYED_REF);
2186
2187         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2188                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2189                                                  num_bytes, parent,
2190                                                  root_objectid, (int)owner,
2191                                                  BTRFS_ADD_DELAYED_REF, NULL,
2192                                                  &old_ref_mod, &new_ref_mod);
2193         } else {
2194                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2195                                                  num_bytes, parent,
2196                                                  root_objectid, owner, offset,
2197                                                  0, BTRFS_ADD_DELAYED_REF,
2198                                                  &old_ref_mod, &new_ref_mod);
2199         }
2200
2201         if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0) {
2202                 bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
2203
2204                 add_pinned_bytes(fs_info, -num_bytes, metadata, root_objectid);
2205         }
2206
2207         return ret;
2208 }
2209
2210 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2211                                   struct btrfs_fs_info *fs_info,
2212                                   struct btrfs_delayed_ref_node *node,
2213                                   u64 parent, u64 root_objectid,
2214                                   u64 owner, u64 offset, int refs_to_add,
2215                                   struct btrfs_delayed_extent_op *extent_op)
2216 {
2217         struct btrfs_path *path;
2218         struct extent_buffer *leaf;
2219         struct btrfs_extent_item *item;
2220         struct btrfs_key key;
2221         u64 bytenr = node->bytenr;
2222         u64 num_bytes = node->num_bytes;
2223         u64 refs;
2224         int ret;
2225
2226         path = btrfs_alloc_path();
2227         if (!path)
2228                 return -ENOMEM;
2229
2230         path->reada = READA_FORWARD;
2231         path->leave_spinning = 1;
2232         /* this will setup the path even if it fails to insert the back ref */
2233         ret = insert_inline_extent_backref(trans, fs_info, path, bytenr,
2234                                            num_bytes, parent, root_objectid,
2235                                            owner, offset,
2236                                            refs_to_add, extent_op);
2237         if ((ret < 0 && ret != -EAGAIN) || !ret)
2238                 goto out;
2239
2240         /*
2241          * Ok we had -EAGAIN which means we didn't have space to insert and
2242          * inline extent ref, so just update the reference count and add a
2243          * normal backref.
2244          */
2245         leaf = path->nodes[0];
2246         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2247         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2248         refs = btrfs_extent_refs(leaf, item);
2249         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2250         if (extent_op)
2251                 __run_delayed_extent_op(extent_op, leaf, item);
2252
2253         btrfs_mark_buffer_dirty(leaf);
2254         btrfs_release_path(path);
2255
2256         path->reada = READA_FORWARD;
2257         path->leave_spinning = 1;
2258         /* now insert the actual backref */
2259         ret = insert_extent_backref(trans, fs_info, path, bytenr, parent,
2260                                     root_objectid, owner, offset, refs_to_add);
2261         if (ret)
2262                 btrfs_abort_transaction(trans, ret);
2263 out:
2264         btrfs_free_path(path);
2265         return ret;
2266 }
2267
2268 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2269                                 struct btrfs_fs_info *fs_info,
2270                                 struct btrfs_delayed_ref_node *node,
2271                                 struct btrfs_delayed_extent_op *extent_op,
2272                                 int insert_reserved)
2273 {
2274         int ret = 0;
2275         struct btrfs_delayed_data_ref *ref;
2276         struct btrfs_key ins;
2277         u64 parent = 0;
2278         u64 ref_root = 0;
2279         u64 flags = 0;
2280
2281         ins.objectid = node->bytenr;
2282         ins.offset = node->num_bytes;
2283         ins.type = BTRFS_EXTENT_ITEM_KEY;
2284
2285         ref = btrfs_delayed_node_to_data_ref(node);
2286         trace_run_delayed_data_ref(fs_info, node, ref, node->action);
2287
2288         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2289                 parent = ref->parent;
2290         ref_root = ref->root;
2291
2292         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2293                 if (extent_op)
2294                         flags |= extent_op->flags_to_set;
2295                 ret = alloc_reserved_file_extent(trans, fs_info,
2296                                                  parent, ref_root, flags,
2297                                                  ref->objectid, ref->offset,
2298                                                  &ins, node->ref_mod);
2299         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2300                 ret = __btrfs_inc_extent_ref(trans, fs_info, node, parent,
2301                                              ref_root, ref->objectid,
2302                                              ref->offset, node->ref_mod,
2303                                              extent_op);
2304         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2305                 ret = __btrfs_free_extent(trans, fs_info, node, parent,
2306                                           ref_root, ref->objectid,
2307                                           ref->offset, node->ref_mod,
2308                                           extent_op);
2309         } else {
2310                 BUG();
2311         }
2312         return ret;
2313 }
2314
2315 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2316                                     struct extent_buffer *leaf,
2317                                     struct btrfs_extent_item *ei)
2318 {
2319         u64 flags = btrfs_extent_flags(leaf, ei);
2320         if (extent_op->update_flags) {
2321                 flags |= extent_op->flags_to_set;
2322                 btrfs_set_extent_flags(leaf, ei, flags);
2323         }
2324
2325         if (extent_op->update_key) {
2326                 struct btrfs_tree_block_info *bi;
2327                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2328                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2329                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2330         }
2331 }
2332
2333 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2334                                  struct btrfs_fs_info *fs_info,
2335                                  struct btrfs_delayed_ref_head *head,
2336                                  struct btrfs_delayed_extent_op *extent_op)
2337 {
2338         struct btrfs_key key;
2339         struct btrfs_path *path;
2340         struct btrfs_extent_item *ei;
2341         struct extent_buffer *leaf;
2342         u32 item_size;
2343         int ret;
2344         int err = 0;
2345         int metadata = !extent_op->is_data;
2346
2347         if (trans->aborted)
2348                 return 0;
2349
2350         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2351                 metadata = 0;
2352
2353         path = btrfs_alloc_path();
2354         if (!path)
2355                 return -ENOMEM;
2356
2357         key.objectid = head->bytenr;
2358
2359         if (metadata) {
2360                 key.type = BTRFS_METADATA_ITEM_KEY;
2361                 key.offset = extent_op->level;
2362         } else {
2363                 key.type = BTRFS_EXTENT_ITEM_KEY;
2364                 key.offset = head->num_bytes;
2365         }
2366
2367 again:
2368         path->reada = READA_FORWARD;
2369         path->leave_spinning = 1;
2370         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
2371         if (ret < 0) {
2372                 err = ret;
2373                 goto out;
2374         }
2375         if (ret > 0) {
2376                 if (metadata) {
2377                         if (path->slots[0] > 0) {
2378                                 path->slots[0]--;
2379                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2380                                                       path->slots[0]);
2381                                 if (key.objectid == head->bytenr &&
2382                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2383                                     key.offset == head->num_bytes)
2384                                         ret = 0;
2385                         }
2386                         if (ret > 0) {
2387                                 btrfs_release_path(path);
2388                                 metadata = 0;
2389
2390                                 key.objectid = head->bytenr;
2391                                 key.offset = head->num_bytes;
2392                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2393                                 goto again;
2394                         }
2395                 } else {
2396                         err = -EIO;
2397                         goto out;
2398                 }
2399         }
2400
2401         leaf = path->nodes[0];
2402         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2403 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2404         if (item_size < sizeof(*ei)) {
2405                 ret = convert_extent_item_v0(trans, fs_info, path, (u64)-1, 0);
2406                 if (ret < 0) {
2407                         err = ret;
2408                         goto out;
2409                 }
2410                 leaf = path->nodes[0];
2411                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2412         }
2413 #endif
2414         BUG_ON(item_size < sizeof(*ei));
2415         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2416         __run_delayed_extent_op(extent_op, leaf, ei);
2417
2418         btrfs_mark_buffer_dirty(leaf);
2419 out:
2420         btrfs_free_path(path);
2421         return err;
2422 }
2423
2424 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2425                                 struct btrfs_fs_info *fs_info,
2426                                 struct btrfs_delayed_ref_node *node,
2427                                 struct btrfs_delayed_extent_op *extent_op,
2428                                 int insert_reserved)
2429 {
2430         int ret = 0;
2431         struct btrfs_delayed_tree_ref *ref;
2432         u64 parent = 0;
2433         u64 ref_root = 0;
2434
2435         ref = btrfs_delayed_node_to_tree_ref(node);
2436         trace_run_delayed_tree_ref(fs_info, node, ref, node->action);
2437
2438         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2439                 parent = ref->parent;
2440         ref_root = ref->root;
2441
2442         if (node->ref_mod != 1) {
2443                 btrfs_err(fs_info,
2444         "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
2445                           node->bytenr, node->ref_mod, node->action, ref_root,
2446                           parent);
2447                 return -EIO;
2448         }
2449         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2450                 BUG_ON(!extent_op || !extent_op->update_flags);
2451                 ret = alloc_reserved_tree_block(trans, node, extent_op);
2452         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2453                 ret = __btrfs_inc_extent_ref(trans, fs_info, node,
2454                                              parent, ref_root,
2455                                              ref->level, 0, 1,
2456                                              extent_op);
2457         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2458                 ret = __btrfs_free_extent(trans, fs_info, node,
2459                                           parent, ref_root,
2460                                           ref->level, 0, 1, extent_op);
2461         } else {
2462                 BUG();
2463         }
2464         return ret;
2465 }
2466
2467 /* helper function to actually process a single delayed ref entry */
2468 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2469                                struct btrfs_fs_info *fs_info,
2470                                struct btrfs_delayed_ref_node *node,
2471                                struct btrfs_delayed_extent_op *extent_op,
2472                                int insert_reserved)
2473 {
2474         int ret = 0;
2475
2476         if (trans->aborted) {
2477                 if (insert_reserved)
2478                         btrfs_pin_extent(fs_info, node->bytenr,
2479                                          node->num_bytes, 1);
2480                 return 0;
2481         }
2482
2483         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2484             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2485                 ret = run_delayed_tree_ref(trans, fs_info, node, extent_op,
2486                                            insert_reserved);
2487         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2488                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2489                 ret = run_delayed_data_ref(trans, fs_info, node, extent_op,
2490                                            insert_reserved);
2491         else
2492                 BUG();
2493         return ret;
2494 }
2495
2496 static inline struct btrfs_delayed_ref_node *
2497 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2498 {
2499         struct btrfs_delayed_ref_node *ref;
2500
2501         if (RB_EMPTY_ROOT(&head->ref_tree))
2502                 return NULL;
2503
2504         /*
2505          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2506          * This is to prevent a ref count from going down to zero, which deletes
2507          * the extent item from the extent tree, when there still are references
2508          * to add, which would fail because they would not find the extent item.
2509          */
2510         if (!list_empty(&head->ref_add_list))
2511                 return list_first_entry(&head->ref_add_list,
2512                                 struct btrfs_delayed_ref_node, add_list);
2513
2514         ref = rb_entry(rb_first(&head->ref_tree),
2515                        struct btrfs_delayed_ref_node, ref_node);
2516         ASSERT(list_empty(&ref->add_list));
2517         return ref;
2518 }
2519
2520 static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
2521                                       struct btrfs_delayed_ref_head *head)
2522 {
2523         spin_lock(&delayed_refs->lock);
2524         head->processing = 0;
2525         delayed_refs->num_heads_ready++;
2526         spin_unlock(&delayed_refs->lock);
2527         btrfs_delayed_ref_unlock(head);
2528 }
2529
2530 static int cleanup_extent_op(struct btrfs_trans_handle *trans,
2531                              struct btrfs_fs_info *fs_info,
2532                              struct btrfs_delayed_ref_head *head)
2533 {
2534         struct btrfs_delayed_extent_op *extent_op = head->extent_op;
2535         int ret;
2536
2537         if (!extent_op)
2538                 return 0;
2539         head->extent_op = NULL;
2540         if (head->must_insert_reserved) {
2541                 btrfs_free_delayed_extent_op(extent_op);
2542                 return 0;
2543         }
2544         spin_unlock(&head->lock);
2545         ret = run_delayed_extent_op(trans, fs_info, head, extent_op);
2546         btrfs_free_delayed_extent_op(extent_op);
2547         return ret ? ret : 1;
2548 }
2549
2550 static int cleanup_ref_head(struct btrfs_trans_handle *trans,
2551                             struct btrfs_fs_info *fs_info,
2552                             struct btrfs_delayed_ref_head *head)
2553 {
2554         struct btrfs_delayed_ref_root *delayed_refs;
2555         int ret;
2556
2557         delayed_refs = &trans->transaction->delayed_refs;
2558
2559         ret = cleanup_extent_op(trans, fs_info, head);
2560         if (ret < 0) {
2561                 unselect_delayed_ref_head(delayed_refs, head);
2562                 btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2563                 return ret;
2564         } else if (ret) {
2565                 return ret;
2566         }
2567
2568         /*
2569          * Need to drop our head ref lock and re-acquire the delayed ref lock
2570          * and then re-check to make sure nobody got added.
2571          */
2572         spin_unlock(&head->lock);
2573         spin_lock(&delayed_refs->lock);
2574         spin_lock(&head->lock);
2575         if (!RB_EMPTY_ROOT(&head->ref_tree) || head->extent_op) {
2576                 spin_unlock(&head->lock);
2577                 spin_unlock(&delayed_refs->lock);
2578                 return 1;
2579         }
2580         delayed_refs->num_heads--;
2581         rb_erase(&head->href_node, &delayed_refs->href_root);
2582         RB_CLEAR_NODE(&head->href_node);
2583         spin_unlock(&head->lock);
2584         spin_unlock(&delayed_refs->lock);
2585         atomic_dec(&delayed_refs->num_entries);
2586
2587         trace_run_delayed_ref_head(fs_info, head, 0);
2588
2589         if (head->total_ref_mod < 0) {
2590                 struct btrfs_space_info *space_info;
2591                 u64 flags;
2592
2593                 if (head->is_data)
2594                         flags = BTRFS_BLOCK_GROUP_DATA;
2595                 else if (head->is_system)
2596                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
2597                 else
2598                         flags = BTRFS_BLOCK_GROUP_METADATA;
2599                 space_info = __find_space_info(fs_info, flags);
2600                 ASSERT(space_info);
2601                 percpu_counter_add(&space_info->total_bytes_pinned,
2602                                    -head->num_bytes);
2603
2604                 if (head->is_data) {
2605                         spin_lock(&delayed_refs->lock);
2606                         delayed_refs->pending_csums -= head->num_bytes;
2607                         spin_unlock(&delayed_refs->lock);
2608                 }
2609         }
2610
2611         if (head->must_insert_reserved) {
2612                 btrfs_pin_extent(fs_info, head->bytenr,
2613                                  head->num_bytes, 1);
2614                 if (head->is_data) {
2615                         ret = btrfs_del_csums(trans, fs_info, head->bytenr,
2616                                               head->num_bytes);
2617                 }
2618         }
2619
2620         /* Also free its reserved qgroup space */
2621         btrfs_qgroup_free_delayed_ref(fs_info, head->qgroup_ref_root,
2622                                       head->qgroup_reserved);
2623         btrfs_delayed_ref_unlock(head);
2624         btrfs_put_delayed_ref_head(head);
2625         return 0;
2626 }
2627
2628 /*
2629  * Returns 0 on success or if called with an already aborted transaction.
2630  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2631  */
2632 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2633                                              unsigned long nr)
2634 {
2635         struct btrfs_fs_info *fs_info = trans->fs_info;
2636         struct btrfs_delayed_ref_root *delayed_refs;
2637         struct btrfs_delayed_ref_node *ref;
2638         struct btrfs_delayed_ref_head *locked_ref = NULL;
2639         struct btrfs_delayed_extent_op *extent_op;
2640         ktime_t start = ktime_get();
2641         int ret;
2642         unsigned long count = 0;
2643         unsigned long actual_count = 0;
2644         int must_insert_reserved = 0;
2645
2646         delayed_refs = &trans->transaction->delayed_refs;
2647         while (1) {
2648                 if (!locked_ref) {
2649                         if (count >= nr)
2650                                 break;
2651
2652                         spin_lock(&delayed_refs->lock);
2653                         locked_ref = btrfs_select_ref_head(trans);
2654                         if (!locked_ref) {
2655                                 spin_unlock(&delayed_refs->lock);
2656                                 break;
2657                         }
2658
2659                         /* grab the lock that says we are going to process
2660                          * all the refs for this head */
2661                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2662                         spin_unlock(&delayed_refs->lock);
2663                         /*
2664                          * we may have dropped the spin lock to get the head
2665                          * mutex lock, and that might have given someone else
2666                          * time to free the head.  If that's true, it has been
2667                          * removed from our list and we can move on.
2668                          */
2669                         if (ret == -EAGAIN) {
2670                                 locked_ref = NULL;
2671                                 count++;
2672                                 continue;
2673                         }
2674                 }
2675
2676                 /*
2677                  * We need to try and merge add/drops of the same ref since we
2678                  * can run into issues with relocate dropping the implicit ref
2679                  * and then it being added back again before the drop can
2680                  * finish.  If we merged anything we need to re-loop so we can
2681                  * get a good ref.
2682                  * Or we can get node references of the same type that weren't
2683                  * merged when created due to bumps in the tree mod seq, and
2684                  * we need to merge them to prevent adding an inline extent
2685                  * backref before dropping it (triggering a BUG_ON at
2686                  * insert_inline_extent_backref()).
2687                  */
2688                 spin_lock(&locked_ref->lock);
2689                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
2690
2691                 ref = select_delayed_ref(locked_ref);
2692
2693                 if (ref && ref->seq &&
2694                     btrfs_check_delayed_seq(fs_info, ref->seq)) {
2695                         spin_unlock(&locked_ref->lock);
2696                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2697                         locked_ref = NULL;
2698                         cond_resched();
2699                         count++;
2700                         continue;
2701                 }
2702
2703                 /*
2704                  * We're done processing refs in this ref_head, clean everything
2705                  * up and move on to the next ref_head.
2706                  */
2707                 if (!ref) {
2708                         ret = cleanup_ref_head(trans, fs_info, locked_ref);
2709                         if (ret > 0 ) {
2710                                 /* We dropped our lock, we need to loop. */
2711                                 ret = 0;
2712                                 continue;
2713                         } else if (ret) {
2714                                 return ret;
2715                         }
2716                         locked_ref = NULL;
2717                         count++;
2718                         continue;
2719                 }
2720
2721                 actual_count++;
2722                 ref->in_tree = 0;
2723                 rb_erase(&ref->ref_node, &locked_ref->ref_tree);
2724                 RB_CLEAR_NODE(&ref->ref_node);
2725                 if (!list_empty(&ref->add_list))
2726                         list_del(&ref->add_list);
2727                 /*
2728                  * When we play the delayed ref, also correct the ref_mod on
2729                  * head
2730                  */
2731                 switch (ref->action) {
2732                 case BTRFS_ADD_DELAYED_REF:
2733                 case BTRFS_ADD_DELAYED_EXTENT:
2734                         locked_ref->ref_mod -= ref->ref_mod;
2735                         break;
2736                 case BTRFS_DROP_DELAYED_REF:
2737                         locked_ref->ref_mod += ref->ref_mod;
2738                         break;
2739                 default:
2740                         WARN_ON(1);
2741                 }
2742                 atomic_dec(&delayed_refs->num_entries);
2743
2744                 /*
2745                  * Record the must-insert_reserved flag before we drop the spin
2746                  * lock.
2747                  */
2748                 must_insert_reserved = locked_ref->must_insert_reserved;
2749                 locked_ref->must_insert_reserved = 0;
2750
2751                 extent_op = locked_ref->extent_op;
2752                 locked_ref->extent_op = NULL;
2753                 spin_unlock(&locked_ref->lock);
2754
2755                 ret = run_one_delayed_ref(trans, fs_info, ref, extent_op,
2756                                           must_insert_reserved);
2757
2758                 btrfs_free_delayed_extent_op(extent_op);
2759                 if (ret) {
2760                         unselect_delayed_ref_head(delayed_refs, locked_ref);
2761                         btrfs_put_delayed_ref(ref);
2762                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
2763                                     ret);
2764                         return ret;
2765                 }
2766
2767                 btrfs_put_delayed_ref(ref);
2768                 count++;
2769                 cond_resched();
2770         }
2771
2772         /*
2773          * We don't want to include ref heads since we can have empty ref heads
2774          * and those will drastically skew our runtime down since we just do
2775          * accounting, no actual extent tree updates.
2776          */
2777         if (actual_count > 0) {
2778                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2779                 u64 avg;
2780
2781                 /*
2782                  * We weigh the current average higher than our current runtime
2783                  * to avoid large swings in the average.
2784                  */
2785                 spin_lock(&delayed_refs->lock);
2786                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2787                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2788                 spin_unlock(&delayed_refs->lock);
2789         }
2790         return 0;
2791 }
2792
2793 #ifdef SCRAMBLE_DELAYED_REFS
2794 /*
2795  * Normally delayed refs get processed in ascending bytenr order. This
2796  * correlates in most cases to the order added. To expose dependencies on this
2797  * order, we start to process the tree in the middle instead of the beginning
2798  */
2799 static u64 find_middle(struct rb_root *root)
2800 {
2801         struct rb_node *n = root->rb_node;
2802         struct btrfs_delayed_ref_node *entry;
2803         int alt = 1;
2804         u64 middle;
2805         u64 first = 0, last = 0;
2806
2807         n = rb_first(root);
2808         if (n) {
2809                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2810                 first = entry->bytenr;
2811         }
2812         n = rb_last(root);
2813         if (n) {
2814                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2815                 last = entry->bytenr;
2816         }
2817         n = root->rb_node;
2818
2819         while (n) {
2820                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2821                 WARN_ON(!entry->in_tree);
2822
2823                 middle = entry->bytenr;
2824
2825                 if (alt)
2826                         n = n->rb_left;
2827                 else
2828                         n = n->rb_right;
2829
2830                 alt = 1 - alt;
2831         }
2832         return middle;
2833 }
2834 #endif
2835
2836 static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
2837 {
2838         u64 num_bytes;
2839
2840         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2841                              sizeof(struct btrfs_extent_inline_ref));
2842         if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2843                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2844
2845         /*
2846          * We don't ever fill up leaves all the way so multiply by 2 just to be
2847          * closer to what we're really going to want to use.
2848          */
2849         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
2850 }
2851
2852 /*
2853  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2854  * would require to store the csums for that many bytes.
2855  */
2856 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2857 {
2858         u64 csum_size;
2859         u64 num_csums_per_leaf;
2860         u64 num_csums;
2861
2862         csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2863         num_csums_per_leaf = div64_u64(csum_size,
2864                         (u64)btrfs_super_csum_size(fs_info->super_copy));
2865         num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2866         num_csums += num_csums_per_leaf - 1;
2867         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2868         return num_csums;
2869 }
2870
2871 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2872                                        struct btrfs_fs_info *fs_info)
2873 {
2874         struct btrfs_block_rsv *global_rsv;
2875         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2876         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2877         unsigned int num_dirty_bgs = trans->transaction->num_dirty_bgs;
2878         u64 num_bytes, num_dirty_bgs_bytes;
2879         int ret = 0;
2880
2881         num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
2882         num_heads = heads_to_leaves(fs_info, num_heads);
2883         if (num_heads > 1)
2884                 num_bytes += (num_heads - 1) * fs_info->nodesize;
2885         num_bytes <<= 1;
2886         num_bytes += btrfs_csum_bytes_to_leaves(fs_info, csum_bytes) *
2887                                                         fs_info->nodesize;
2888         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(fs_info,
2889                                                              num_dirty_bgs);
2890         global_rsv = &fs_info->global_block_rsv;
2891
2892         /*
2893          * If we can't allocate any more chunks lets make sure we have _lots_ of
2894          * wiggle room since running delayed refs can create more delayed refs.
2895          */
2896         if (global_rsv->space_info->full) {
2897                 num_dirty_bgs_bytes <<= 1;
2898                 num_bytes <<= 1;
2899         }
2900
2901         spin_lock(&global_rsv->lock);
2902         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2903                 ret = 1;
2904         spin_unlock(&global_rsv->lock);
2905         return ret;
2906 }
2907
2908 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2909                                        struct btrfs_fs_info *fs_info)
2910 {
2911         u64 num_entries =
2912                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2913         u64 avg_runtime;
2914         u64 val;
2915
2916         smp_mb();
2917         avg_runtime = fs_info->avg_delayed_ref_runtime;
2918         val = num_entries * avg_runtime;
2919         if (val >= NSEC_PER_SEC)
2920                 return 1;
2921         if (val >= NSEC_PER_SEC / 2)
2922                 return 2;
2923
2924         return btrfs_check_space_for_delayed_refs(trans, fs_info);
2925 }
2926
2927 struct async_delayed_refs {
2928         struct btrfs_root *root;
2929         u64 transid;
2930         int count;
2931         int error;
2932         int sync;
2933         struct completion wait;
2934         struct btrfs_work work;
2935 };
2936
2937 static inline struct async_delayed_refs *
2938 to_async_delayed_refs(struct btrfs_work *work)
2939 {
2940         return container_of(work, struct async_delayed_refs, work);
2941 }
2942
2943 static void delayed_ref_async_start(struct btrfs_work *work)
2944 {
2945         struct async_delayed_refs *async = to_async_delayed_refs(work);
2946         struct btrfs_trans_handle *trans;
2947         struct btrfs_fs_info *fs_info = async->root->fs_info;
2948         int ret;
2949
2950         /* if the commit is already started, we don't need to wait here */
2951         if (btrfs_transaction_blocked(fs_info))
2952                 goto done;
2953
2954         trans = btrfs_join_transaction(async->root);
2955         if (IS_ERR(trans)) {
2956                 async->error = PTR_ERR(trans);
2957                 goto done;
2958         }
2959
2960         /*
2961          * trans->sync means that when we call end_transaction, we won't
2962          * wait on delayed refs
2963          */
2964         trans->sync = true;
2965
2966         /* Don't bother flushing if we got into a different transaction */
2967         if (trans->transid > async->transid)
2968                 goto end;
2969
2970         ret = btrfs_run_delayed_refs(trans, async->count);
2971         if (ret)
2972                 async->error = ret;
2973 end:
2974         ret = btrfs_end_transaction(trans);
2975         if (ret && !async->error)
2976                 async->error = ret;
2977 done:
2978         if (async->sync)
2979                 complete(&async->wait);
2980         else
2981                 kfree(async);
2982 }
2983
2984 int btrfs_async_run_delayed_refs(struct btrfs_fs_info *fs_info,
2985                                  unsigned long count, u64 transid, int wait)
2986 {
2987         struct async_delayed_refs *async;
2988         int ret;
2989
2990         async = kmalloc(sizeof(*async), GFP_NOFS);
2991         if (!async)
2992                 return -ENOMEM;
2993
2994         async->root = fs_info->tree_root;
2995         async->count = count;
2996         async->error = 0;
2997         async->transid = transid;
2998         if (wait)
2999                 async->sync = 1;
3000         else
3001                 async->sync = 0;
3002         init_completion(&async->wait);
3003
3004         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
3005                         delayed_ref_async_start, NULL, NULL);
3006
3007         btrfs_queue_work(fs_info->extent_workers, &async->work);
3008
3009         if (wait) {
3010                 wait_for_completion(&async->wait);
3011                 ret = async->error;
3012                 kfree(async);
3013                 return ret;
3014         }
3015         return 0;
3016 }
3017
3018 /*
3019  * this starts processing the delayed reference count updates and
3020  * extent insertions we have queued up so far.  count can be
3021  * 0, which means to process everything in the tree at the start
3022  * of the run (but not newly added entries), or it can be some target
3023  * number you'd like to process.
3024  *
3025  * Returns 0 on success or if called with an aborted transaction
3026  * Returns <0 on error and aborts the transaction
3027  */
3028 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
3029                            unsigned long count)
3030 {
3031         struct btrfs_fs_info *fs_info = trans->fs_info;
3032         struct rb_node *node;
3033         struct btrfs_delayed_ref_root *delayed_refs;
3034         struct btrfs_delayed_ref_head *head;
3035         int ret;
3036         int run_all = count == (unsigned long)-1;
3037         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
3038
3039         /* We'll clean this up in btrfs_cleanup_transaction */
3040         if (trans->aborted)
3041                 return 0;
3042
3043         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
3044                 return 0;
3045
3046         delayed_refs = &trans->transaction->delayed_refs;
3047         if (count == 0)
3048                 count = atomic_read(&delayed_refs->num_entries) * 2;
3049
3050 again:
3051 #ifdef SCRAMBLE_DELAYED_REFS
3052         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
3053 #endif
3054         trans->can_flush_pending_bgs = false;
3055         ret = __btrfs_run_delayed_refs(trans, count);
3056         if (ret < 0) {
3057                 btrfs_abort_transaction(trans, ret);
3058                 return ret;
3059         }
3060
3061         if (run_all) {
3062                 if (!list_empty(&trans->new_bgs))
3063                         btrfs_create_pending_block_groups(trans);
3064
3065                 spin_lock(&delayed_refs->lock);
3066                 node = rb_first(&delayed_refs->href_root);
3067                 if (!node) {
3068                         spin_unlock(&delayed_refs->lock);
3069                         goto out;
3070                 }
3071                 head = rb_entry(node, struct btrfs_delayed_ref_head,
3072                                 href_node);
3073                 refcount_inc(&head->refs);
3074                 spin_unlock(&delayed_refs->lock);
3075
3076                 /* Mutex was contended, block until it's released and retry. */
3077                 mutex_lock(&head->mutex);
3078                 mutex_unlock(&head->mutex);
3079
3080                 btrfs_put_delayed_ref_head(head);
3081                 cond_resched();
3082                 goto again;
3083         }
3084 out:
3085         trans->can_flush_pending_bgs = can_flush_pending_bgs;
3086         return 0;
3087 }
3088
3089 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3090                                 struct btrfs_fs_info *fs_info,
3091                                 u64 bytenr, u64 num_bytes, u64 flags,
3092                                 int level, int is_data)
3093 {
3094         struct btrfs_delayed_extent_op *extent_op;
3095         int ret;
3096
3097         extent_op = btrfs_alloc_delayed_extent_op();
3098         if (!extent_op)
3099                 return -ENOMEM;
3100
3101         extent_op->flags_to_set = flags;
3102         extent_op->update_flags = true;
3103         extent_op->update_key = false;
3104         extent_op->is_data = is_data ? true : false;
3105         extent_op->level = level;
3106
3107         ret = btrfs_add_delayed_extent_op(fs_info, trans, bytenr,
3108                                           num_bytes, extent_op);
3109         if (ret)
3110                 btrfs_free_delayed_extent_op(extent_op);
3111         return ret;
3112 }
3113
3114 static noinline int check_delayed_ref(struct btrfs_root *root,
3115                                       struct btrfs_path *path,
3116                                       u64 objectid, u64 offset, u64 bytenr)
3117 {
3118         struct btrfs_delayed_ref_head *head;
3119         struct btrfs_delayed_ref_node *ref;
3120         struct btrfs_delayed_data_ref *data_ref;
3121         struct btrfs_delayed_ref_root *delayed_refs;
3122         struct btrfs_transaction *cur_trans;
3123         struct rb_node *node;
3124         int ret = 0;
3125
3126         spin_lock(&root->fs_info->trans_lock);
3127         cur_trans = root->fs_info->running_transaction;
3128         if (cur_trans)
3129                 refcount_inc(&cur_trans->use_count);
3130         spin_unlock(&root->fs_info->trans_lock);
3131         if (!cur_trans)
3132                 return 0;
3133
3134         delayed_refs = &cur_trans->delayed_refs;
3135         spin_lock(&delayed_refs->lock);
3136         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3137         if (!head) {
3138                 spin_unlock(&delayed_refs->lock);
3139                 btrfs_put_transaction(cur_trans);
3140                 return 0;
3141         }
3142
3143         if (!mutex_trylock(&head->mutex)) {
3144                 refcount_inc(&head->refs);
3145                 spin_unlock(&delayed_refs->lock);
3146
3147                 btrfs_release_path(path);
3148
3149                 /*
3150                  * Mutex was contended, block until it's released and let
3151                  * caller try again
3152                  */
3153                 mutex_lock(&head->mutex);
3154                 mutex_unlock(&head->mutex);
3155                 btrfs_put_delayed_ref_head(head);
3156                 btrfs_put_transaction(cur_trans);
3157                 return -EAGAIN;
3158         }
3159         spin_unlock(&delayed_refs->lock);
3160
3161         spin_lock(&head->lock);
3162         /*
3163          * XXX: We should replace this with a proper search function in the
3164          * future.
3165          */
3166         for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
3167                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
3168                 /* If it's a shared ref we know a cross reference exists */
3169                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3170                         ret = 1;
3171                         break;
3172                 }
3173
3174                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3175
3176                 /*
3177                  * If our ref doesn't match the one we're currently looking at
3178                  * then we have a cross reference.
3179                  */
3180                 if (data_ref->root != root->root_key.objectid ||
3181                     data_ref->objectid != objectid ||
3182                     data_ref->offset != offset) {
3183                         ret = 1;
3184                         break;
3185                 }
3186         }
3187         spin_unlock(&head->lock);
3188         mutex_unlock(&head->mutex);
3189         btrfs_put_transaction(cur_trans);
3190         return ret;
3191 }
3192
3193 static noinline int check_committed_ref(struct btrfs_root *root,
3194                                         struct btrfs_path *path,
3195                                         u64 objectid, u64 offset, u64 bytenr)
3196 {
3197         struct btrfs_fs_info *fs_info = root->fs_info;
3198         struct btrfs_root *extent_root = fs_info->extent_root;
3199         struct extent_buffer *leaf;
3200         struct btrfs_extent_data_ref *ref;
3201         struct btrfs_extent_inline_ref *iref;
3202         struct btrfs_extent_item *ei;
3203         struct btrfs_key key;
3204         u32 item_size;
3205         int type;
3206         int ret;
3207
3208         key.objectid = bytenr;
3209         key.offset = (u64)-1;
3210         key.type = BTRFS_EXTENT_ITEM_KEY;
3211
3212         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3213         if (ret < 0)
3214                 goto out;
3215         BUG_ON(ret == 0); /* Corruption */
3216
3217         ret = -ENOENT;
3218         if (path->slots[0] == 0)
3219                 goto out;
3220
3221         path->slots[0]--;
3222         leaf = path->nodes[0];
3223         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3224
3225         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3226                 goto out;
3227
3228         ret = 1;
3229         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3230 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3231         if (item_size < sizeof(*ei)) {
3232                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3233                 goto out;
3234         }
3235 #endif
3236         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3237
3238         if (item_size != sizeof(*ei) +
3239             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3240                 goto out;
3241
3242         if (btrfs_extent_generation(leaf, ei) <=
3243             btrfs_root_last_snapshot(&root->root_item))
3244                 goto out;
3245
3246         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3247
3248         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
3249         if (type != BTRFS_EXTENT_DATA_REF_KEY)
3250                 goto out;
3251
3252         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3253         if (btrfs_extent_refs(leaf, ei) !=
3254             btrfs_extent_data_ref_count(leaf, ref) ||
3255             btrfs_extent_data_ref_root(leaf, ref) !=
3256             root->root_key.objectid ||
3257             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3258             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3259                 goto out;
3260
3261         ret = 0;
3262 out:
3263         return ret;
3264 }
3265
3266 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
3267                           u64 bytenr)
3268 {
3269         struct btrfs_path *path;
3270         int ret;
3271         int ret2;
3272
3273         path = btrfs_alloc_path();
3274         if (!path)
3275                 return -ENOMEM;
3276
3277         do {
3278                 ret = check_committed_ref(root, path, objectid,
3279                                           offset, bytenr);
3280                 if (ret && ret != -ENOENT)
3281                         goto out;
3282
3283                 ret2 = check_delayed_ref(root, path, objectid,
3284                                          offset, bytenr);
3285         } while (ret2 == -EAGAIN);
3286
3287         if (ret2 && ret2 != -ENOENT) {
3288                 ret = ret2;
3289                 goto out;
3290         }
3291
3292         if (ret != -ENOENT || ret2 != -ENOENT)
3293                 ret = 0;
3294 out:
3295         btrfs_free_path(path);
3296         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3297                 WARN_ON(ret > 0);
3298         return ret;
3299 }
3300
3301 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3302                            struct btrfs_root *root,
3303                            struct extent_buffer *buf,
3304                            int full_backref, int inc)
3305 {
3306         struct btrfs_fs_info *fs_info = root->fs_info;
3307         u64 bytenr;
3308         u64 num_bytes;
3309         u64 parent;
3310         u64 ref_root;
3311         u32 nritems;
3312         struct btrfs_key key;
3313         struct btrfs_file_extent_item *fi;
3314         int i;
3315         int level;
3316         int ret = 0;
3317         int (*process_func)(struct btrfs_trans_handle *,
3318                             struct btrfs_root *,
3319                             u64, u64, u64, u64, u64, u64);
3320
3321
3322         if (btrfs_is_testing(fs_info))
3323                 return 0;
3324
3325         ref_root = btrfs_header_owner(buf);
3326         nritems = btrfs_header_nritems(buf);
3327         level = btrfs_header_level(buf);
3328
3329         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3330                 return 0;
3331
3332         if (inc)
3333                 process_func = btrfs_inc_extent_ref;
3334         else
3335                 process_func = btrfs_free_extent;
3336
3337         if (full_backref)
3338                 parent = buf->start;
3339         else
3340                 parent = 0;
3341
3342         for (i = 0; i < nritems; i++) {
3343                 if (level == 0) {
3344                         btrfs_item_key_to_cpu(buf, &key, i);
3345                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3346                                 continue;
3347                         fi = btrfs_item_ptr(buf, i,
3348                                             struct btrfs_file_extent_item);
3349                         if (btrfs_file_extent_type(buf, fi) ==
3350                             BTRFS_FILE_EXTENT_INLINE)
3351                                 continue;
3352                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3353                         if (bytenr == 0)
3354                                 continue;
3355
3356                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3357                         key.offset -= btrfs_file_extent_offset(buf, fi);
3358                         ret = process_func(trans, root, bytenr, num_bytes,
3359                                            parent, ref_root, key.objectid,
3360                                            key.offset);
3361                         if (ret)
3362                                 goto fail;
3363                 } else {
3364                         bytenr = btrfs_node_blockptr(buf, i);
3365                         num_bytes = fs_info->nodesize;
3366                         ret = process_func(trans, root, bytenr, num_bytes,
3367                                            parent, ref_root, level - 1, 0);
3368                         if (ret)
3369                                 goto fail;
3370                 }
3371         }
3372         return 0;
3373 fail:
3374         return ret;
3375 }
3376
3377 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3378                   struct extent_buffer *buf, int full_backref)
3379 {
3380         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3381 }
3382
3383 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3384                   struct extent_buffer *buf, int full_backref)
3385 {
3386         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3387 }
3388
3389 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3390                                  struct btrfs_fs_info *fs_info,
3391                                  struct btrfs_path *path,
3392                                  struct btrfs_block_group_cache *cache)
3393 {
3394         int ret;
3395         struct btrfs_root *extent_root = fs_info->extent_root;
3396         unsigned long bi;
3397         struct extent_buffer *leaf;
3398
3399         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3400         if (ret) {
3401                 if (ret > 0)
3402                         ret = -ENOENT;
3403                 goto fail;
3404         }
3405
3406         leaf = path->nodes[0];
3407         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3408         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3409         btrfs_mark_buffer_dirty(leaf);
3410 fail:
3411         btrfs_release_path(path);
3412         return ret;
3413
3414 }
3415
3416 static struct btrfs_block_group_cache *
3417 next_block_group(struct btrfs_fs_info *fs_info,
3418                  struct btrfs_block_group_cache *cache)
3419 {
3420         struct rb_node *node;
3421
3422         spin_lock(&fs_info->block_group_cache_lock);
3423
3424         /* If our block group was removed, we need a full search. */
3425         if (RB_EMPTY_NODE(&cache->cache_node)) {
3426                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3427
3428                 spin_unlock(&fs_info->block_group_cache_lock);
3429                 btrfs_put_block_group(cache);
3430                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
3431         }
3432         node = rb_next(&cache->cache_node);
3433         btrfs_put_block_group(cache);
3434         if (node) {
3435                 cache = rb_entry(node, struct btrfs_block_group_cache,
3436                                  cache_node);
3437                 btrfs_get_block_group(cache);
3438         } else
3439                 cache = NULL;
3440         spin_unlock(&fs_info->block_group_cache_lock);
3441         return cache;
3442 }
3443
3444 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3445                             struct btrfs_trans_handle *trans,
3446                             struct btrfs_path *path)
3447 {
3448         struct btrfs_fs_info *fs_info = block_group->fs_info;
3449         struct btrfs_root *root = fs_info->tree_root;
3450         struct inode *inode = NULL;
3451         struct extent_changeset *data_reserved = NULL;
3452         u64 alloc_hint = 0;
3453         int dcs = BTRFS_DC_ERROR;
3454         u64 num_pages = 0;
3455         int retries = 0;
3456         int ret = 0;
3457
3458         /*
3459          * If this block group is smaller than 100 megs don't bother caching the
3460          * block group.
3461          */
3462         if (block_group->key.offset < (100 * SZ_1M)) {
3463                 spin_lock(&block_group->lock);
3464                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3465                 spin_unlock(&block_group->lock);
3466                 return 0;
3467         }
3468
3469         if (trans->aborted)
3470                 return 0;
3471 again:
3472         inode = lookup_free_space_inode(fs_info, block_group, path);
3473         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3474                 ret = PTR_ERR(inode);
3475                 btrfs_release_path(path);
3476                 goto out;
3477         }
3478
3479         if (IS_ERR(inode)) {
3480                 BUG_ON(retries);
3481                 retries++;
3482
3483                 if (block_group->ro)
3484                         goto out_free;
3485
3486                 ret = create_free_space_inode(fs_info, trans, block_group,
3487                                               path);
3488                 if (ret)
3489                         goto out_free;
3490                 goto again;
3491         }
3492
3493         /*
3494          * We want to set the generation to 0, that way if anything goes wrong
3495          * from here on out we know not to trust this cache when we load up next
3496          * time.
3497          */
3498         BTRFS_I(inode)->generation = 0;
3499         ret = btrfs_update_inode(trans, root, inode);
3500         if (ret) {
3501                 /*
3502                  * So theoretically we could recover from this, simply set the
3503                  * super cache generation to 0 so we know to invalidate the
3504                  * cache, but then we'd have to keep track of the block groups
3505                  * that fail this way so we know we _have_ to reset this cache
3506                  * before the next commit or risk reading stale cache.  So to
3507                  * limit our exposure to horrible edge cases lets just abort the
3508                  * transaction, this only happens in really bad situations
3509                  * anyway.
3510                  */
3511                 btrfs_abort_transaction(trans, ret);
3512                 goto out_put;
3513         }
3514         WARN_ON(ret);
3515
3516         /* We've already setup this transaction, go ahead and exit */
3517         if (block_group->cache_generation == trans->transid &&
3518             i_size_read(inode)) {
3519                 dcs = BTRFS_DC_SETUP;
3520                 goto out_put;
3521         }
3522
3523         if (i_size_read(inode) > 0) {
3524                 ret = btrfs_check_trunc_cache_free_space(fs_info,
3525                                         &fs_info->global_block_rsv);
3526                 if (ret)
3527                         goto out_put;
3528
3529                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3530                 if (ret)
3531                         goto out_put;
3532         }
3533
3534         spin_lock(&block_group->lock);
3535         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3536             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3537                 /*
3538                  * don't bother trying to write stuff out _if_
3539                  * a) we're not cached,
3540                  * b) we're with nospace_cache mount option,
3541                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
3542                  */
3543                 dcs = BTRFS_DC_WRITTEN;
3544                 spin_unlock(&block_group->lock);
3545                 goto out_put;
3546         }
3547         spin_unlock(&block_group->lock);
3548
3549         /*
3550          * We hit an ENOSPC when setting up the cache in this transaction, just
3551          * skip doing the setup, we've already cleared the cache so we're safe.
3552          */
3553         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3554                 ret = -ENOSPC;
3555                 goto out_put;
3556         }
3557
3558         /*
3559          * Try to preallocate enough space based on how big the block group is.
3560          * Keep in mind this has to include any pinned space which could end up
3561          * taking up quite a bit since it's not folded into the other space
3562          * cache.
3563          */
3564         num_pages = div_u64(block_group->key.offset, SZ_256M);
3565         if (!num_pages)
3566                 num_pages = 1;
3567
3568         num_pages *= 16;
3569         num_pages *= PAGE_SIZE;
3570
3571         ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
3572         if (ret)
3573                 goto out_put;
3574
3575         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3576                                               num_pages, num_pages,
3577                                               &alloc_hint);
3578         /*
3579          * Our cache requires contiguous chunks so that we don't modify a bunch
3580          * of metadata or split extents when writing the cache out, which means
3581          * we can enospc if we are heavily fragmented in addition to just normal
3582          * out of space conditions.  So if we hit this just skip setting up any
3583          * other block groups for this transaction, maybe we'll unpin enough
3584          * space the next time around.
3585          */
3586         if (!ret)
3587                 dcs = BTRFS_DC_SETUP;
3588         else if (ret == -ENOSPC)
3589                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3590
3591 out_put:
3592         iput(inode);
3593 out_free:
3594         btrfs_release_path(path);
3595 out:
3596         spin_lock(&block_group->lock);
3597         if (!ret && dcs == BTRFS_DC_SETUP)
3598                 block_group->cache_generation = trans->transid;
3599         block_group->disk_cache_state = dcs;
3600         spin_unlock(&block_group->lock);
3601
3602         extent_changeset_free(data_reserved);
3603         return ret;
3604 }
3605
3606 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3607                             struct btrfs_fs_info *fs_info)
3608 {
3609         struct btrfs_block_group_cache *cache, *tmp;
3610         struct btrfs_transaction *cur_trans = trans->transaction;
3611         struct btrfs_path *path;
3612
3613         if (list_empty(&cur_trans->dirty_bgs) ||
3614             !btrfs_test_opt(fs_info, SPACE_CACHE))
3615                 return 0;
3616
3617         path = btrfs_alloc_path();
3618         if (!path)
3619                 return -ENOMEM;
3620
3621         /* Could add new block groups, use _safe just in case */
3622         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3623                                  dirty_list) {
3624                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3625                         cache_save_setup(cache, trans, path);
3626         }
3627
3628         btrfs_free_path(path);
3629         return 0;
3630 }
3631
3632 /*
3633  * transaction commit does final block group cache writeback during a
3634  * critical section where nothing is allowed to change the FS.  This is
3635  * required in order for the cache to actually match the block group,
3636  * but can introduce a lot of latency into the commit.
3637  *
3638  * So, btrfs_start_dirty_block_groups is here to kick off block group
3639  * cache IO.  There's a chance we'll have to redo some of it if the
3640  * block group changes again during the commit, but it greatly reduces
3641  * the commit latency by getting rid of the easy block groups while
3642  * we're still allowing others to join the commit.
3643  */
3644 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
3645 {
3646         struct btrfs_fs_info *fs_info = trans->fs_info;
3647         struct btrfs_block_group_cache *cache;
3648         struct btrfs_transaction *cur_trans = trans->transaction;
3649         int ret = 0;
3650         int should_put;
3651         struct btrfs_path *path = NULL;
3652         LIST_HEAD(dirty);
3653         struct list_head *io = &cur_trans->io_bgs;
3654         int num_started = 0;
3655         int loops = 0;
3656
3657         spin_lock(&cur_trans->dirty_bgs_lock);
3658         if (list_empty(&cur_trans->dirty_bgs)) {
3659                 spin_unlock(&cur_trans->dirty_bgs_lock);
3660                 return 0;
3661         }
3662         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3663         spin_unlock(&cur_trans->dirty_bgs_lock);
3664
3665 again:
3666         /*
3667          * make sure all the block groups on our dirty list actually
3668          * exist
3669          */
3670         btrfs_create_pending_block_groups(trans);
3671
3672         if (!path) {
3673                 path = btrfs_alloc_path();
3674                 if (!path)
3675                         return -ENOMEM;
3676         }
3677
3678         /*
3679          * cache_write_mutex is here only to save us from balance or automatic
3680          * removal of empty block groups deleting this block group while we are
3681          * writing out the cache
3682          */
3683         mutex_lock(&trans->transaction->cache_write_mutex);
3684         while (!list_empty(&dirty)) {
3685                 cache = list_first_entry(&dirty,
3686                                          struct btrfs_block_group_cache,
3687                                          dirty_list);
3688                 /*
3689                  * this can happen if something re-dirties a block
3690                  * group that is already under IO.  Just wait for it to
3691                  * finish and then do it all again
3692                  */
3693                 if (!list_empty(&cache->io_list)) {
3694                         list_del_init(&cache->io_list);
3695                         btrfs_wait_cache_io(trans, cache, path);
3696                         btrfs_put_block_group(cache);
3697                 }
3698
3699
3700                 /*
3701                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3702                  * if it should update the cache_state.  Don't delete
3703                  * until after we wait.
3704                  *
3705                  * Since we're not running in the commit critical section
3706                  * we need the dirty_bgs_lock to protect from update_block_group
3707                  */
3708                 spin_lock(&cur_trans->dirty_bgs_lock);
3709                 list_del_init(&cache->dirty_list);
3710                 spin_unlock(&cur_trans->dirty_bgs_lock);
3711
3712                 should_put = 1;
3713
3714                 cache_save_setup(cache, trans, path);
3715
3716                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3717                         cache->io_ctl.inode = NULL;
3718                         ret = btrfs_write_out_cache(fs_info, trans,
3719                                                     cache, path);
3720                         if (ret == 0 && cache->io_ctl.inode) {
3721                                 num_started++;
3722                                 should_put = 0;
3723
3724                                 /*
3725                                  * The cache_write_mutex is protecting the
3726                                  * io_list, also refer to the definition of
3727                                  * btrfs_transaction::io_bgs for more details
3728                                  */
3729                                 list_add_tail(&cache->io_list, io);
3730                         } else {
3731                                 /*
3732                                  * if we failed to write the cache, the
3733                                  * generation will be bad and life goes on
3734                                  */
3735                                 ret = 0;
3736                         }
3737                 }
3738                 if (!ret) {
3739                         ret = write_one_cache_group(trans, fs_info,
3740                                                     path, cache);
3741                         /*
3742                          * Our block group might still be attached to the list
3743                          * of new block groups in the transaction handle of some
3744                          * other task (struct btrfs_trans_handle->new_bgs). This
3745                          * means its block group item isn't yet in the extent
3746                          * tree. If this happens ignore the error, as we will
3747                          * try again later in the critical section of the
3748                          * transaction commit.
3749                          */
3750                         if (ret == -ENOENT) {
3751                                 ret = 0;
3752                                 spin_lock(&cur_trans->dirty_bgs_lock);
3753                                 if (list_empty(&cache->dirty_list)) {
3754                                         list_add_tail(&cache->dirty_list,
3755                                                       &cur_trans->dirty_bgs);
3756                                         btrfs_get_block_group(cache);
3757                                 }
3758                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3759                         } else if (ret) {
3760                                 btrfs_abort_transaction(trans, ret);
3761                         }
3762                 }
3763
3764                 /* if its not on the io list, we need to put the block group */
3765                 if (should_put)
3766                         btrfs_put_block_group(cache);
3767
3768                 if (ret)
3769                         break;
3770
3771                 /*
3772                  * Avoid blocking other tasks for too long. It might even save
3773                  * us from writing caches for block groups that are going to be
3774                  * removed.
3775                  */
3776                 mutex_unlock(&trans->transaction->cache_write_mutex);
3777                 mutex_lock(&trans->transaction->cache_write_mutex);
3778         }
3779         mutex_unlock(&trans->transaction->cache_write_mutex);
3780
3781         /*
3782          * go through delayed refs for all the stuff we've just kicked off
3783          * and then loop back (just once)
3784          */
3785         ret = btrfs_run_delayed_refs(trans, 0);
3786         if (!ret && loops == 0) {
3787                 loops++;
3788                 spin_lock(&cur_trans->dirty_bgs_lock);
3789                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3790                 /*
3791                  * dirty_bgs_lock protects us from concurrent block group
3792                  * deletes too (not just cache_write_mutex).
3793                  */
3794                 if (!list_empty(&dirty)) {
3795                         spin_unlock(&cur_trans->dirty_bgs_lock);
3796                         goto again;
3797                 }
3798                 spin_unlock(&cur_trans->dirty_bgs_lock);
3799         } else if (ret < 0) {
3800                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3801         }
3802
3803         btrfs_free_path(path);
3804         return ret;
3805 }
3806
3807 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3808                                    struct btrfs_fs_info *fs_info)
3809 {
3810         struct btrfs_block_group_cache *cache;
3811         struct btrfs_transaction *cur_trans = trans->transaction;
3812         int ret = 0;
3813         int should_put;
3814         struct btrfs_path *path;
3815         struct list_head *io = &cur_trans->io_bgs;
3816         int num_started = 0;
3817
3818         path = btrfs_alloc_path();
3819         if (!path)
3820                 return -ENOMEM;
3821
3822         /*
3823          * Even though we are in the critical section of the transaction commit,
3824          * we can still have concurrent tasks adding elements to this
3825          * transaction's list of dirty block groups. These tasks correspond to
3826          * endio free space workers started when writeback finishes for a
3827          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3828          * allocate new block groups as a result of COWing nodes of the root
3829          * tree when updating the free space inode. The writeback for the space
3830          * caches is triggered by an earlier call to
3831          * btrfs_start_dirty_block_groups() and iterations of the following
3832          * loop.
3833          * Also we want to do the cache_save_setup first and then run the
3834          * delayed refs to make sure we have the best chance at doing this all
3835          * in one shot.
3836          */
3837         spin_lock(&cur_trans->dirty_bgs_lock);
3838         while (!list_empty(&cur_trans->dirty_bgs)) {
3839                 cache = list_first_entry(&cur_trans->dirty_bgs,
3840                                          struct btrfs_block_group_cache,
3841                                          dirty_list);
3842
3843                 /*
3844                  * this can happen if cache_save_setup re-dirties a block
3845                  * group that is already under IO.  Just wait for it to
3846                  * finish and then do it all again
3847                  */
3848                 if (!list_empty(&cache->io_list)) {
3849                         spin_unlock(&cur_trans->dirty_bgs_lock);
3850                         list_del_init(&cache->io_list);
3851                         btrfs_wait_cache_io(trans, cache, path);
3852                         btrfs_put_block_group(cache);
3853                         spin_lock(&cur_trans->dirty_bgs_lock);
3854                 }
3855
3856                 /*
3857                  * don't remove from the dirty list until after we've waited
3858                  * on any pending IO
3859                  */
3860                 list_del_init(&cache->dirty_list);
3861                 spin_unlock(&cur_trans->dirty_bgs_lock);
3862                 should_put = 1;
3863
3864                 cache_save_setup(cache, trans, path);
3865
3866                 if (!ret)
3867                         ret = btrfs_run_delayed_refs(trans,
3868                                                      (unsigned long) -1);
3869
3870                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3871                         cache->io_ctl.inode = NULL;
3872                         ret = btrfs_write_out_cache(fs_info, trans,
3873                                                     cache, path);
3874                         if (ret == 0 && cache->io_ctl.inode) {
3875                                 num_started++;
3876                                 should_put = 0;
3877                                 list_add_tail(&cache->io_list, io);
3878                         } else {
3879                                 /*
3880                                  * if we failed to write the cache, the
3881                                  * generation will be bad and life goes on
3882                                  */
3883                                 ret = 0;
3884                         }
3885                 }
3886                 if (!ret) {
3887                         ret = write_one_cache_group(trans, fs_info,
3888                                                     path, cache);
3889                         /*
3890                          * One of the free space endio workers might have
3891                          * created a new block group while updating a free space
3892                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3893                          * and hasn't released its transaction handle yet, in
3894                          * which case the new block group is still attached to
3895                          * its transaction handle and its creation has not
3896                          * finished yet (no block group item in the extent tree
3897                          * yet, etc). If this is the case, wait for all free
3898                          * space endio workers to finish and retry. This is a
3899                          * a very rare case so no need for a more efficient and
3900                          * complex approach.
3901                          */
3902                         if (ret == -ENOENT) {
3903                                 wait_event(cur_trans->writer_wait,
3904                                    atomic_read(&cur_trans->num_writers) == 1);
3905                                 ret = write_one_cache_group(trans, fs_info,
3906                                                             path, cache);
3907                         }
3908                         if (ret)
3909                                 btrfs_abort_transaction(trans, ret);
3910                 }
3911
3912                 /* if its not on the io list, we need to put the block group */
3913                 if (should_put)
3914                         btrfs_put_block_group(cache);
3915                 spin_lock(&cur_trans->dirty_bgs_lock);
3916         }
3917         spin_unlock(&cur_trans->dirty_bgs_lock);
3918
3919         /*
3920          * Refer to the definition of io_bgs member for details why it's safe
3921          * to use it without any locking
3922          */
3923         while (!list_empty(io)) {
3924                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3925                                          io_list);
3926                 list_del_init(&cache->io_list);
3927                 btrfs_wait_cache_io(trans, cache, path);
3928                 btrfs_put_block_group(cache);
3929         }
3930
3931         btrfs_free_path(path);
3932         return ret;
3933 }
3934
3935 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
3936 {
3937         struct btrfs_block_group_cache *block_group;
3938         int readonly = 0;
3939
3940         block_group = btrfs_lookup_block_group(fs_info, bytenr);
3941         if (!block_group || block_group->ro)
3942                 readonly = 1;
3943         if (block_group)
3944                 btrfs_put_block_group(block_group);
3945         return readonly;
3946 }
3947
3948 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3949 {
3950         struct btrfs_block_group_cache *bg;
3951         bool ret = true;
3952
3953         bg = btrfs_lookup_block_group(fs_info, bytenr);
3954         if (!bg)
3955                 return false;
3956
3957         spin_lock(&bg->lock);
3958         if (bg->ro)
3959                 ret = false;
3960         else
3961                 atomic_inc(&bg->nocow_writers);
3962         spin_unlock(&bg->lock);
3963
3964         /* no put on block group, done by btrfs_dec_nocow_writers */
3965         if (!ret)
3966                 btrfs_put_block_group(bg);
3967
3968         return ret;
3969
3970 }
3971
3972 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3973 {
3974         struct btrfs_block_group_cache *bg;
3975
3976         bg = btrfs_lookup_block_group(fs_info, bytenr);
3977         ASSERT(bg);
3978         if (atomic_dec_and_test(&bg->nocow_writers))
3979                 wake_up_var(&bg->nocow_writers);
3980         /*
3981          * Once for our lookup and once for the lookup done by a previous call
3982          * to btrfs_inc_nocow_writers()
3983          */
3984         btrfs_put_block_group(bg);
3985         btrfs_put_block_group(bg);
3986 }
3987
3988 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
3989 {
3990         wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
3991 }
3992
3993 static const char *alloc_name(u64 flags)
3994 {
3995         switch (flags) {
3996         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3997                 return "mixed";
3998         case BTRFS_BLOCK_GROUP_METADATA:
3999                 return "metadata";
4000         case BTRFS_BLOCK_GROUP_DATA:
4001                 return "data";
4002         case BTRFS_BLOCK_GROUP_SYSTEM:
4003                 return "system";
4004         default:
4005                 WARN_ON(1);
4006                 return "invalid-combination";
4007         };
4008 }
4009
4010 static int create_space_info(struct btrfs_fs_info *info, u64 flags)
4011 {
4012
4013         struct btrfs_space_info *space_info;
4014         int i;
4015         int ret;
4016
4017         space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
4018         if (!space_info)
4019                 return -ENOMEM;
4020
4021         ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
4022                                  GFP_KERNEL);
4023         if (ret) {
4024                 kfree(space_info);
4025                 return ret;
4026         }
4027
4028         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
4029                 INIT_LIST_HEAD(&space_info->block_groups[i]);
4030         init_rwsem(&space_info->groups_sem);
4031         spin_lock_init(&space_info->lock);
4032         space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
4033         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4034         init_waitqueue_head(&space_info->wait);
4035         INIT_LIST_HEAD(&space_info->ro_bgs);
4036         INIT_LIST_HEAD(&space_info->tickets);
4037         INIT_LIST_HEAD(&space_info->priority_tickets);
4038
4039         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
4040                                     info->space_info_kobj, "%s",
4041                                     alloc_name(space_info->flags));
4042         if (ret) {
4043                 percpu_counter_destroy(&space_info->total_bytes_pinned);
4044                 kfree(space_info);
4045                 return ret;
4046         }
4047
4048         list_add_rcu(&space_info->list, &info->space_info);
4049         if (flags & BTRFS_BLOCK_GROUP_DATA)
4050                 info->data_sinfo = space_info;
4051
4052         return ret;
4053 }
4054
4055 static void update_space_info(struct btrfs_fs_info *info, u64 flags,
4056                              u64 total_bytes, u64 bytes_used,
4057                              u64 bytes_readonly,
4058                              struct btrfs_space_info **space_info)
4059 {
4060         struct btrfs_space_info *found;
4061         int factor;
4062
4063         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
4064                      BTRFS_BLOCK_GROUP_RAID10))
4065                 factor = 2;
4066         else
4067                 factor = 1;
4068
4069         found = __find_space_info(info, flags);
4070         ASSERT(found);
4071         spin_lock(&found->lock);
4072         found->total_bytes += total_bytes;
4073         found->disk_total += total_bytes * factor;
4074         found->bytes_used += bytes_used;
4075         found->disk_used += bytes_used * factor;
4076         found->bytes_readonly += bytes_readonly;
4077         if (total_bytes > 0)
4078                 found->full = 0;
4079         space_info_add_new_bytes(info, found, total_bytes -
4080                                  bytes_used - bytes_readonly);
4081         spin_unlock(&found->lock);
4082         *space_info = found;
4083 }
4084
4085 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
4086 {
4087         u64 extra_flags = chunk_to_extended(flags) &
4088                                 BTRFS_EXTENDED_PROFILE_MASK;
4089
4090         write_seqlock(&fs_info->profiles_lock);
4091         if (flags & BTRFS_BLOCK_GROUP_DATA)
4092                 fs_info->avail_data_alloc_bits |= extra_flags;
4093         if (flags & BTRFS_BLOCK_GROUP_METADATA)
4094                 fs_info->avail_metadata_alloc_bits |= extra_flags;
4095         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4096                 fs_info->avail_system_alloc_bits |= extra_flags;
4097         write_sequnlock(&fs_info->profiles_lock);
4098 }
4099
4100 /*
4101  * returns target flags in extended format or 0 if restripe for this
4102  * chunk_type is not in progress
4103  *
4104  * should be called with balance_lock held
4105  */
4106 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4107 {
4108         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4109         u64 target = 0;
4110
4111         if (!bctl)
4112                 return 0;
4113
4114         if (flags & BTRFS_BLOCK_GROUP_DATA &&
4115             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4116                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4117         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4118                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4119                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4120         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4121                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4122                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4123         }
4124
4125         return target;
4126 }
4127
4128 /*
4129  * @flags: available profiles in extended format (see ctree.h)
4130  *
4131  * Returns reduced profile in chunk format.  If profile changing is in
4132  * progress (either running or paused) picks the target profile (if it's
4133  * already available), otherwise falls back to plain reducing.
4134  */
4135 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
4136 {
4137         u64 num_devices = fs_info->fs_devices->rw_devices;
4138         u64 target;
4139         u64 raid_type;
4140         u64 allowed = 0;
4141
4142         /*
4143          * see if restripe for this chunk_type is in progress, if so
4144          * try to reduce to the target profile
4145          */
4146         spin_lock(&fs_info->balance_lock);
4147         target = get_restripe_target(fs_info, flags);
4148         if (target) {
4149                 /* pick target profile only if it's already available */
4150                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4151                         spin_unlock(&fs_info->balance_lock);
4152                         return extended_to_chunk(target);
4153                 }
4154         }
4155         spin_unlock(&fs_info->balance_lock);
4156
4157         /* First, mask out the RAID levels which aren't possible */
4158         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4159                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4160                         allowed |= btrfs_raid_array[raid_type].bg_flag;
4161         }
4162         allowed &= flags;
4163
4164         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4165                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4166         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4167                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4168         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4169                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4170         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4171                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4172         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4173                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4174
4175         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4176
4177         return extended_to_chunk(flags | allowed);
4178 }
4179
4180 static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
4181 {
4182         unsigned seq;
4183         u64 flags;
4184
4185         do {
4186                 flags = orig_flags;
4187                 seq = read_seqbegin(&fs_info->profiles_lock);
4188
4189                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4190                         flags |= fs_info->avail_data_alloc_bits;
4191                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4192                         flags |= fs_info->avail_system_alloc_bits;
4193                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4194                         flags |= fs_info->avail_metadata_alloc_bits;
4195         } while (read_seqretry(&fs_info->profiles_lock, seq));
4196
4197         return btrfs_reduce_alloc_profile(fs_info, flags);
4198 }
4199
4200 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
4201 {
4202         struct btrfs_fs_info *fs_info = root->fs_info;
4203         u64 flags;
4204         u64 ret;
4205
4206         if (data)
4207                 flags = BTRFS_BLOCK_GROUP_DATA;
4208         else if (root == fs_info->chunk_root)
4209                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4210         else
4211                 flags = BTRFS_BLOCK_GROUP_METADATA;
4212
4213         ret = get_alloc_profile(fs_info, flags);
4214         return ret;
4215 }
4216
4217 u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
4218 {
4219         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
4220 }
4221
4222 u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
4223 {
4224         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4225 }
4226
4227 u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
4228 {
4229         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4230 }
4231
4232 static u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
4233                                  bool may_use_included)
4234 {
4235         ASSERT(s_info);
4236         return s_info->bytes_used + s_info->bytes_reserved +
4237                 s_info->bytes_pinned + s_info->bytes_readonly +
4238                 (may_use_included ? s_info->bytes_may_use : 0);
4239 }
4240
4241 int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes)
4242 {
4243         struct btrfs_root *root = inode->root;
4244         struct btrfs_fs_info *fs_info = root->fs_info;
4245         struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
4246         u64 used;
4247         int ret = 0;
4248         int need_commit = 2;
4249         int have_pinned_space;
4250
4251         /* make sure bytes are sectorsize aligned */
4252         bytes = ALIGN(bytes, fs_info->sectorsize);
4253
4254         if (btrfs_is_free_space_inode(inode)) {
4255                 need_commit = 0;
4256                 ASSERT(current->journal_info);
4257         }
4258
4259 again:
4260         /* make sure we have enough space to handle the data first */
4261         spin_lock(&data_sinfo->lock);
4262         used = btrfs_space_info_used(data_sinfo, true);
4263
4264         if (used + bytes > data_sinfo->total_bytes) {
4265                 struct btrfs_trans_handle *trans;
4266
4267                 /*
4268                  * if we don't have enough free bytes in this space then we need
4269                  * to alloc a new chunk.
4270                  */
4271                 if (!data_sinfo->full) {
4272                         u64 alloc_target;
4273
4274                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4275                         spin_unlock(&data_sinfo->lock);
4276
4277                         alloc_target = btrfs_data_alloc_profile(fs_info);
4278                         /*
4279                          * It is ugly that we don't call nolock join
4280                          * transaction for the free space inode case here.
4281                          * But it is safe because we only do the data space
4282                          * reservation for the free space cache in the
4283                          * transaction context, the common join transaction
4284                          * just increase the counter of the current transaction
4285                          * handler, doesn't try to acquire the trans_lock of
4286                          * the fs.
4287                          */
4288                         trans = btrfs_join_transaction(root);
4289                         if (IS_ERR(trans))
4290                                 return PTR_ERR(trans);
4291
4292                         ret = do_chunk_alloc(trans, fs_info, alloc_target,
4293                                              CHUNK_ALLOC_NO_FORCE);
4294                         btrfs_end_transaction(trans);
4295                         if (ret < 0) {
4296                                 if (ret != -ENOSPC)
4297                                         return ret;
4298                                 else {
4299                                         have_pinned_space = 1;
4300                                         goto commit_trans;
4301                                 }
4302                         }
4303
4304                         goto again;
4305                 }
4306
4307                 /*
4308                  * If we don't have enough pinned space to deal with this
4309                  * allocation, and no removed chunk in current transaction,
4310                  * don't bother committing the transaction.
4311                  */
4312                 have_pinned_space = percpu_counter_compare(
4313                         &data_sinfo->total_bytes_pinned,
4314                         used + bytes - data_sinfo->total_bytes);
4315                 spin_unlock(&data_sinfo->lock);
4316
4317                 /* commit the current transaction and try again */
4318 commit_trans:
4319                 if (need_commit) {
4320                         need_commit--;
4321
4322                         if (need_commit > 0) {
4323                                 btrfs_start_delalloc_roots(fs_info, -1);
4324                                 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0,
4325                                                          (u64)-1);
4326                         }
4327
4328                         trans = btrfs_join_transaction(root);
4329                         if (IS_ERR(trans))
4330                                 return PTR_ERR(trans);
4331                         if (have_pinned_space >= 0 ||
4332                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4333                                      &trans->transaction->flags) ||
4334                             need_commit > 0) {
4335                                 ret = btrfs_commit_transaction(trans);
4336                                 if (ret)
4337                                         return ret;
4338                                 /*
4339                                  * The cleaner kthread might still be doing iput
4340                                  * operations. Wait for it to finish so that
4341                                  * more space is released.
4342                                  */
4343                                 mutex_lock(&fs_info->cleaner_delayed_iput_mutex);
4344                                 mutex_unlock(&fs_info->cleaner_delayed_iput_mutex);
4345                                 goto again;
4346                         } else {
4347                                 btrfs_end_transaction(trans);
4348                         }
4349                 }
4350
4351                 trace_btrfs_space_reservation(fs_info,
4352                                               "space_info:enospc",
4353                                               data_sinfo->flags, bytes, 1);
4354                 return -ENOSPC;
4355         }
4356         data_sinfo->bytes_may_use += bytes;
4357         trace_btrfs_space_reservation(fs_info, "space_info",
4358                                       data_sinfo->flags, bytes, 1);
4359         spin_unlock(&data_sinfo->lock);
4360
4361         return ret;
4362 }
4363
4364 int btrfs_check_data_free_space(struct inode *inode,
4365                         struct extent_changeset **reserved, u64 start, u64 len)
4366 {
4367         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4368         int ret;
4369
4370         /* align the range */
4371         len = round_up(start + len, fs_info->sectorsize) -
4372               round_down(start, fs_info->sectorsize);
4373         start = round_down(start, fs_info->sectorsize);
4374
4375         ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), len);
4376         if (ret < 0)
4377                 return ret;
4378
4379         /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4380         ret = btrfs_qgroup_reserve_data(inode, reserved, start, len);
4381         if (ret < 0)
4382                 btrfs_free_reserved_data_space_noquota(inode, start, len);
4383         else
4384                 ret = 0;
4385         return ret;
4386 }
4387
4388 /*
4389  * Called if we need to clear a data reservation for this inode
4390  * Normally in a error case.
4391  *
4392  * This one will *NOT* use accurate qgroup reserved space API, just for case
4393  * which we can't sleep and is sure it won't affect qgroup reserved space.
4394  * Like clear_bit_hook().
4395  */
4396 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4397                                             u64 len)
4398 {
4399         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4400         struct btrfs_space_info *data_sinfo;
4401
4402         /* Make sure the range is aligned to sectorsize */
4403         len = round_up(start + len, fs_info->sectorsize) -
4404               round_down(start, fs_info->sectorsize);
4405         start = round_down(start, fs_info->sectorsize);
4406
4407         data_sinfo = fs_info->data_sinfo;
4408         spin_lock(&data_sinfo->lock);
4409         if (WARN_ON(data_sinfo->bytes_may_use < len))
4410                 data_sinfo->bytes_may_use = 0;
4411         else
4412                 data_sinfo->bytes_may_use -= len;
4413         trace_btrfs_space_reservation(fs_info, "space_info",
4414                                       data_sinfo->flags, len, 0);
4415         spin_unlock(&data_sinfo->lock);
4416 }
4417
4418 /*
4419  * Called if we need to clear a data reservation for this inode
4420  * Normally in a error case.
4421  *
4422  * This one will handle the per-inode data rsv map for accurate reserved
4423  * space framework.
4424  */
4425 void btrfs_free_reserved_data_space(struct inode *inode,
4426                         struct extent_changeset *reserved, u64 start, u64 len)
4427 {
4428         struct btrfs_root *root = BTRFS_I(inode)->root;
4429
4430         /* Make sure the range is aligned to sectorsize */
4431         len = round_up(start + len, root->fs_info->sectorsize) -
4432               round_down(start, root->fs_info->sectorsize);
4433         start = round_down(start, root->fs_info->sectorsize);
4434
4435         btrfs_free_reserved_data_space_noquota(inode, start, len);
4436         btrfs_qgroup_free_data(inode, reserved, start, len);
4437 }
4438
4439 static void force_metadata_allocation(struct btrfs_fs_info *info)
4440 {
4441         struct list_head *head = &info->space_info;
4442         struct btrfs_space_info *found;
4443
4444         rcu_read_lock();
4445         list_for_each_entry_rcu(found, head, list) {
4446                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4447                         found->force_alloc = CHUNK_ALLOC_FORCE;
4448         }
4449         rcu_read_unlock();
4450 }
4451
4452 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4453 {
4454         return (global->size << 1);
4455 }
4456
4457 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
4458                               struct btrfs_space_info *sinfo, int force)
4459 {
4460         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4461         u64 bytes_used = btrfs_space_info_used(sinfo, false);
4462         u64 thresh;
4463
4464         if (force == CHUNK_ALLOC_FORCE)
4465                 return 1;
4466
4467         /*
4468          * We need to take into account the global rsv because for all intents
4469          * and purposes it's used space.  Don't worry about locking the
4470          * global_rsv, it doesn't change except when the transaction commits.
4471          */
4472         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4473                 bytes_used += calc_global_rsv_need_space(global_rsv);
4474
4475         /*
4476          * in limited mode, we want to have some free space up to
4477          * about 1% of the FS size.
4478          */
4479         if (force == CHUNK_ALLOC_LIMITED) {
4480                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
4481                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4482
4483                 if (sinfo->total_bytes - bytes_used < thresh)
4484                         return 1;
4485         }
4486
4487         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
4488                 return 0;
4489         return 1;
4490 }
4491
4492 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4493 {
4494         u64 num_dev;
4495
4496         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4497                     BTRFS_BLOCK_GROUP_RAID0 |
4498                     BTRFS_BLOCK_GROUP_RAID5 |
4499                     BTRFS_BLOCK_GROUP_RAID6))
4500                 num_dev = fs_info->fs_devices->rw_devices;
4501         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4502                 num_dev = 2;
4503         else
4504                 num_dev = 1;    /* DUP or single */
4505
4506         return num_dev;
4507 }
4508
4509 /*
4510  * If @is_allocation is true, reserve space in the system space info necessary
4511  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4512  * removing a chunk.
4513  */
4514 void check_system_chunk(struct btrfs_trans_handle *trans,
4515                         struct btrfs_fs_info *fs_info, u64 type)
4516 {
4517         struct btrfs_space_info *info;
4518         u64 left;
4519         u64 thresh;
4520         int ret = 0;
4521         u64 num_devs;
4522
4523         /*
4524          * Needed because we can end up allocating a system chunk and for an
4525          * atomic and race free space reservation in the chunk block reserve.
4526          */
4527         lockdep_assert_held(&fs_info->chunk_mutex);
4528
4529         info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4530         spin_lock(&info->lock);
4531         left = info->total_bytes - btrfs_space_info_used(info, true);
4532         spin_unlock(&info->lock);
4533
4534         num_devs = get_profile_num_devs(fs_info, type);
4535
4536         /* num_devs device items to update and 1 chunk item to add or remove */
4537         thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
4538                 btrfs_calc_trans_metadata_size(fs_info, 1);
4539
4540         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4541                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4542                            left, thresh, type);
4543                 dump_space_info(fs_info, info, 0, 0);
4544         }
4545
4546         if (left < thresh) {
4547                 u64 flags = btrfs_system_alloc_profile(fs_info);
4548
4549                 /*
4550                  * Ignore failure to create system chunk. We might end up not
4551                  * needing it, as we might not need to COW all nodes/leafs from
4552                  * the paths we visit in the chunk tree (they were already COWed
4553                  * or created in the current transaction for example).
4554                  */
4555                 ret = btrfs_alloc_chunk(trans, fs_info, flags);
4556         }
4557
4558         if (!ret) {
4559                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
4560                                           &fs_info->chunk_block_rsv,
4561                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4562                 if (!ret)
4563                         trans->chunk_bytes_reserved += thresh;
4564         }
4565 }
4566
4567 /*
4568  * If force is CHUNK_ALLOC_FORCE:
4569  *    - return 1 if it successfully allocates a chunk,
4570  *    - return errors including -ENOSPC otherwise.
4571  * If force is NOT CHUNK_ALLOC_FORCE:
4572  *    - return 0 if it doesn't need to allocate a new chunk,
4573  *    - return 1 if it successfully allocates a chunk,
4574  *    - return errors including -ENOSPC otherwise.
4575  */
4576 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4577                           struct btrfs_fs_info *fs_info, u64 flags, int force)
4578 {
4579         struct btrfs_space_info *space_info;
4580         int wait_for_alloc = 0;
4581         int ret = 0;
4582
4583         /* Don't re-enter if we're already allocating a chunk */
4584         if (trans->allocating_chunk)
4585                 return -ENOSPC;
4586
4587         space_info = __find_space_info(fs_info, flags);
4588         ASSERT(space_info);
4589
4590 again:
4591         spin_lock(&space_info->lock);
4592         if (force < space_info->force_alloc)
4593                 force = space_info->force_alloc;
4594         if (space_info->full) {
4595                 if (should_alloc_chunk(fs_info, space_info, force))
4596                         ret = -ENOSPC;
4597                 else
4598                         ret = 0;
4599                 spin_unlock(&space_info->lock);
4600                 return ret;
4601         }
4602
4603         if (!should_alloc_chunk(fs_info, space_info, force)) {
4604                 spin_unlock(&space_info->lock);
4605                 return 0;
4606         } else if (space_info->chunk_alloc) {
4607                 wait_for_alloc = 1;
4608         } else {
4609                 space_info->chunk_alloc = 1;
4610         }
4611
4612         spin_unlock(&space_info->lock);
4613
4614         mutex_lock(&fs_info->chunk_mutex);
4615
4616         /*
4617          * The chunk_mutex is held throughout the entirety of a chunk
4618          * allocation, so once we've acquired the chunk_mutex we know that the
4619          * other guy is done and we need to recheck and see if we should
4620          * allocate.
4621          */
4622         if (wait_for_alloc) {
4623                 mutex_unlock(&fs_info->chunk_mutex);
4624                 wait_for_alloc = 0;
4625                 cond_resched();
4626                 goto again;
4627         }
4628
4629         trans->allocating_chunk = true;
4630
4631         /*
4632          * If we have mixed data/metadata chunks we want to make sure we keep
4633          * allocating mixed chunks instead of individual chunks.
4634          */
4635         if (btrfs_mixed_space_info(space_info))
4636                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4637
4638         /*
4639          * if we're doing a data chunk, go ahead and make sure that
4640          * we keep a reasonable number of metadata chunks allocated in the
4641          * FS as well.
4642          */
4643         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4644                 fs_info->data_chunk_allocations++;
4645                 if (!(fs_info->data_chunk_allocations %
4646                       fs_info->metadata_ratio))
4647                         force_metadata_allocation(fs_info);
4648         }
4649
4650         /*
4651          * Check if we have enough space in SYSTEM chunk because we may need
4652          * to update devices.
4653          */
4654         check_system_chunk(trans, fs_info, flags);
4655
4656         ret = btrfs_alloc_chunk(trans, fs_info, flags);
4657         trans->allocating_chunk = false;
4658
4659         spin_lock(&space_info->lock);
4660         if (ret < 0) {
4661                 if (ret == -ENOSPC)
4662                         space_info->full = 1;
4663                 else
4664                         goto out;
4665         } else {
4666                 ret = 1;
4667         }
4668
4669         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4670 out:
4671         space_info->chunk_alloc = 0;
4672         spin_unlock(&space_info->lock);
4673         mutex_unlock(&fs_info->chunk_mutex);
4674         /*
4675          * When we allocate a new chunk we reserve space in the chunk block
4676          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4677          * add new nodes/leafs to it if we end up needing to do it when
4678          * inserting the chunk item and updating device items as part of the
4679          * second phase of chunk allocation, performed by
4680          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4681          * large number of new block groups to create in our transaction
4682          * handle's new_bgs list to avoid exhausting the chunk block reserve
4683          * in extreme cases - like having a single transaction create many new
4684          * block groups when starting to write out the free space caches of all
4685          * the block groups that were made dirty during the lifetime of the
4686          * transaction.
4687          */
4688         if (trans->can_flush_pending_bgs &&
4689             trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4690                 btrfs_create_pending_block_groups(trans);
4691                 btrfs_trans_release_chunk_metadata(trans);
4692         }
4693         return ret;
4694 }
4695
4696 static int can_overcommit(struct btrfs_fs_info *fs_info,
4697                           struct btrfs_space_info *space_info, u64 bytes,
4698                           enum btrfs_reserve_flush_enum flush,
4699                           bool system_chunk)
4700 {
4701         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4702         u64 profile;
4703         u64 space_size;
4704         u64 avail;
4705         u64 used;
4706
4707         /* Don't overcommit when in mixed mode. */
4708         if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4709                 return 0;
4710
4711         if (system_chunk)
4712                 profile = btrfs_system_alloc_profile(fs_info);
4713         else
4714                 profile = btrfs_metadata_alloc_profile(fs_info);
4715
4716         used = btrfs_space_info_used(space_info, false);
4717
4718         /*
4719          * We only want to allow over committing if we have lots of actual space
4720          * free, but if we don't have enough space to handle the global reserve
4721          * space then we could end up having a real enospc problem when trying
4722          * to allocate a chunk or some other such important allocation.
4723          */
4724         spin_lock(&global_rsv->lock);
4725         space_size = calc_global_rsv_need_space(global_rsv);
4726         spin_unlock(&global_rsv->lock);
4727         if (used + space_size >= space_info->total_bytes)
4728                 return 0;
4729
4730         used += space_info->bytes_may_use;
4731
4732         avail = atomic64_read(&fs_info->free_chunk_space);
4733
4734         /*
4735          * If we have dup, raid1 or raid10 then only half of the free
4736          * space is actually useable.  For raid56, the space info used
4737          * doesn't include the parity drive, so we don't have to
4738          * change the math
4739          */
4740         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4741                        BTRFS_BLOCK_GROUP_RAID1 |
4742                        BTRFS_BLOCK_GROUP_RAID10))
4743                 avail >>= 1;
4744
4745         /*
4746          * If we aren't flushing all things, let us overcommit up to
4747          * 1/2th of the space. If we can flush, don't let us overcommit
4748          * too much, let it overcommit up to 1/8 of the space.
4749          */
4750         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4751                 avail >>= 3;
4752         else
4753                 avail >>= 1;
4754
4755         if (used + bytes < space_info->total_bytes + avail)
4756                 return 1;
4757         return 0;
4758 }
4759
4760 static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
4761                                          unsigned long nr_pages, int nr_items)
4762 {
4763         struct super_block *sb = fs_info->sb;
4764
4765         if (down_read_trylock(&sb->s_umount)) {
4766                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4767                 up_read(&sb->s_umount);
4768         } else {
4769                 /*
4770                  * We needn't worry the filesystem going from r/w to r/o though
4771                  * we don't acquire ->s_umount mutex, because the filesystem
4772                  * should guarantee the delalloc inodes list be empty after
4773                  * the filesystem is readonly(all dirty pages are written to
4774                  * the disk).
4775                  */
4776                 btrfs_start_delalloc_roots(fs_info, nr_items);
4777                 if (!current->journal_info)
4778                         btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
4779         }
4780 }
4781
4782 static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
4783                                         u64 to_reclaim)
4784 {
4785         u64 bytes;
4786         u64 nr;
4787
4788         bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
4789         nr = div64_u64(to_reclaim, bytes);
4790         if (!nr)
4791                 nr = 1;
4792         return nr;
4793 }
4794
4795 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4796
4797 /*
4798  * shrink metadata reservation for delalloc
4799  */
4800 static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
4801                             u64 orig, bool wait_ordered)
4802 {
4803         struct btrfs_space_info *space_info;
4804         struct btrfs_trans_handle *trans;
4805         u64 delalloc_bytes;
4806         u64 max_reclaim;
4807         u64 items;
4808         long time_left;
4809         unsigned long nr_pages;
4810         int loops;
4811
4812         /* Calc the number of the pages we need flush for space reservation */
4813         items = calc_reclaim_items_nr(fs_info, to_reclaim);
4814         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4815
4816         trans = (struct btrfs_trans_handle *)current->journal_info;
4817         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4818
4819         delalloc_bytes = percpu_counter_sum_positive(
4820                                                 &fs_info->delalloc_bytes);
4821         if (delalloc_bytes == 0) {
4822                 if (trans)
4823                         return;
4824                 if (wait_ordered)
4825                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4826                 return;
4827         }
4828
4829         loops = 0;
4830         while (delalloc_bytes && loops < 3) {
4831                 max_reclaim = min(delalloc_bytes, to_reclaim);
4832                 nr_pages = max_reclaim >> PAGE_SHIFT;
4833                 btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items);
4834                 /*
4835                  * We need to wait for the async pages to actually start before
4836                  * we do anything.
4837                  */
4838                 max_reclaim = atomic_read(&fs_info->async_delalloc_pages);
4839                 if (!max_reclaim)
4840                         goto skip_async;
4841
4842                 if (max_reclaim <= nr_pages)
4843                         max_reclaim = 0;
4844                 else
4845                         max_reclaim -= nr_pages;
4846
4847                 wait_event(fs_info->async_submit_wait,
4848                            atomic_read(&fs_info->async_delalloc_pages) <=
4849                            (int)max_reclaim);
4850 skip_async:
4851                 spin_lock(&space_info->lock);
4852                 if (list_empty(&space_info->tickets) &&
4853                     list_empty(&space_info->priority_tickets)) {
4854                         spin_unlock(&space_info->lock);
4855                         break;
4856                 }
4857                 spin_unlock(&space_info->lock);
4858
4859                 loops++;
4860                 if (wait_ordered && !trans) {
4861                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4862                 } else {
4863                         time_left = schedule_timeout_killable(1);
4864                         if (time_left)
4865                                 break;
4866                 }
4867                 delalloc_bytes = percpu_counter_sum_positive(
4868                                                 &fs_info->delalloc_bytes);
4869         }
4870 }
4871
4872 struct reserve_ticket {
4873         u64 bytes;
4874         int error;
4875         struct list_head list;
4876         wait_queue_head_t wait;
4877 };
4878
4879 /**
4880  * maybe_commit_transaction - possibly commit the transaction if its ok to
4881  * @root - the root we're allocating for
4882  * @bytes - the number of bytes we want to reserve
4883  * @force - force the commit
4884  *
4885  * This will check to make sure that committing the transaction will actually
4886  * get us somewhere and then commit the transaction if it does.  Otherwise it
4887  * will return -ENOSPC.
4888  */
4889 static int may_commit_transaction(struct btrfs_fs_info *fs_info,
4890                                   struct btrfs_space_info *space_info)
4891 {
4892         struct reserve_ticket *ticket = NULL;
4893         struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
4894         struct btrfs_trans_handle *trans;
4895         u64 bytes;
4896
4897         trans = (struct btrfs_trans_handle *)current->journal_info;
4898         if (trans)
4899                 return -EAGAIN;
4900
4901         spin_lock(&space_info->lock);
4902         if (!list_empty(&space_info->priority_tickets))
4903                 ticket = list_first_entry(&space_info->priority_tickets,
4904                                           struct reserve_ticket, list);
4905         else if (!list_empty(&space_info->tickets))
4906                 ticket = list_first_entry(&space_info->tickets,
4907                                           struct reserve_ticket, list);
4908         bytes = (ticket) ? ticket->bytes : 0;
4909         spin_unlock(&space_info->lock);
4910
4911         if (!bytes)
4912                 return 0;
4913
4914         /* See if there is enough pinned space to make this reservation */
4915         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4916                                    bytes) >= 0)
4917                 goto commit;
4918
4919         /*
4920          * See if there is some space in the delayed insertion reservation for
4921          * this reservation.
4922          */
4923         if (space_info != delayed_rsv->space_info)
4924                 return -ENOSPC;
4925
4926         spin_lock(&delayed_rsv->lock);
4927         if (delayed_rsv->size > bytes)
4928                 bytes = 0;
4929         else
4930                 bytes -= delayed_rsv->size;
4931         spin_unlock(&delayed_rsv->lock);
4932
4933         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4934                                    bytes) < 0) {
4935                 return -ENOSPC;
4936         }
4937
4938 commit:
4939         trans = btrfs_join_transaction(fs_info->extent_root);
4940         if (IS_ERR(trans))
4941                 return -ENOSPC;
4942
4943         return btrfs_commit_transaction(trans);
4944 }
4945
4946 /*
4947  * Try to flush some data based on policy set by @state. This is only advisory
4948  * and may fail for various reasons. The caller is supposed to examine the
4949  * state of @space_info to detect the outcome.
4950  */
4951 static void flush_space(struct btrfs_fs_info *fs_info,
4952                        struct btrfs_space_info *space_info, u64 num_bytes,
4953                        int state)
4954 {
4955         struct btrfs_root *root = fs_info->extent_root;
4956         struct btrfs_trans_handle *trans;
4957         int nr;
4958         int ret = 0;
4959
4960         switch (state) {
4961         case FLUSH_DELAYED_ITEMS_NR:
4962         case FLUSH_DELAYED_ITEMS:
4963                 if (state == FLUSH_DELAYED_ITEMS_NR)
4964                         nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
4965                 else
4966                         nr = -1;
4967
4968                 trans = btrfs_join_transaction(root);
4969                 if (IS_ERR(trans)) {
4970                         ret = PTR_ERR(trans);
4971                         break;
4972                 }
4973                 ret = btrfs_run_delayed_items_nr(trans, nr);
4974                 btrfs_end_transaction(trans);
4975                 break;
4976         case FLUSH_DELALLOC:
4977         case FLUSH_DELALLOC_WAIT:
4978                 shrink_delalloc(fs_info, num_bytes * 2, num_bytes,
4979                                 state == FLUSH_DELALLOC_WAIT);
4980                 break;
4981         case ALLOC_CHUNK:
4982                 trans = btrfs_join_transaction(root);
4983                 if (IS_ERR(trans)) {
4984                         ret = PTR_ERR(trans);
4985                         break;
4986                 }
4987                 ret = do_chunk_alloc(trans, fs_info,
4988                                      btrfs_metadata_alloc_profile(fs_info),
4989                                      CHUNK_ALLOC_NO_FORCE);
4990                 btrfs_end_transaction(trans);
4991                 if (ret > 0 || ret == -ENOSPC)
4992                         ret = 0;
4993                 break;
4994         case COMMIT_TRANS:
4995                 ret = may_commit_transaction(fs_info, space_info);
4996                 break;
4997         default:
4998                 ret = -ENOSPC;
4999                 break;
5000         }
5001
5002         trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
5003                                 ret);
5004         return;
5005 }
5006
5007 static inline u64
5008 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
5009                                  struct btrfs_space_info *space_info,
5010                                  bool system_chunk)
5011 {
5012         struct reserve_ticket *ticket;
5013         u64 used;
5014         u64 expected;
5015         u64 to_reclaim = 0;
5016
5017         list_for_each_entry(ticket, &space_info->tickets, list)
5018                 to_reclaim += ticket->bytes;
5019         list_for_each_entry(ticket, &space_info->priority_tickets, list)
5020                 to_reclaim += ticket->bytes;
5021         if (to_reclaim)
5022                 return to_reclaim;
5023
5024         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
5025         if (can_overcommit(fs_info, space_info, to_reclaim,
5026                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
5027                 return 0;
5028
5029         used = btrfs_space_info_used(space_info, true);
5030
5031         if (can_overcommit(fs_info, space_info, SZ_1M,
5032                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
5033                 expected = div_factor_fine(space_info->total_bytes, 95);
5034         else
5035                 expected = div_factor_fine(space_info->total_bytes, 90);
5036
5037         if (used > expected)
5038                 to_reclaim = used - expected;
5039         else
5040                 to_reclaim = 0;
5041         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
5042                                      space_info->bytes_reserved);
5043         return to_reclaim;
5044 }
5045
5046 static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
5047                                         struct btrfs_space_info *space_info,
5048                                         u64 used, bool system_chunk)
5049 {
5050         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
5051
5052         /* If we're just plain full then async reclaim just slows us down. */
5053         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
5054                 return 0;
5055
5056         if (!btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5057                                               system_chunk))
5058                 return 0;
5059
5060         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
5061                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
5062 }
5063
5064 static void wake_all_tickets(struct list_head *head)
5065 {
5066         struct reserve_ticket *ticket;
5067
5068         while (!list_empty(head)) {
5069                 ticket = list_first_entry(head, struct reserve_ticket, list);
5070                 list_del_init(&ticket->list);
5071                 ticket->error = -ENOSPC;
5072                 wake_up(&ticket->wait);
5073         }
5074 }
5075
5076 /*
5077  * This is for normal flushers, we can wait all goddamned day if we want to.  We
5078  * will loop and continuously try to flush as long as we are making progress.
5079  * We count progress as clearing off tickets each time we have to loop.
5080  */
5081 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
5082 {
5083         struct btrfs_fs_info *fs_info;
5084         struct btrfs_space_info *space_info;
5085         u64 to_reclaim;
5086         int flush_state;
5087         int commit_cycles = 0;
5088         u64 last_tickets_id;
5089
5090         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
5091         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5092
5093         spin_lock(&space_info->lock);
5094         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5095                                                       false);
5096         if (!to_reclaim) {
5097                 space_info->flush = 0;
5098                 spin_unlock(&space_info->lock);
5099                 return;
5100         }
5101         last_tickets_id = space_info->tickets_id;
5102         spin_unlock(&space_info->lock);
5103
5104         flush_state = FLUSH_DELAYED_ITEMS_NR;
5105         do {
5106                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5107                 spin_lock(&space_info->lock);
5108                 if (list_empty(&space_info->tickets)) {
5109                         space_info->flush = 0;
5110                         spin_unlock(&space_info->lock);
5111                         return;
5112                 }
5113                 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
5114                                                               space_info,
5115                                                               false);
5116                 if (last_tickets_id == space_info->tickets_id) {
5117                         flush_state++;
5118                 } else {
5119                         last_tickets_id = space_info->tickets_id;
5120                         flush_state = FLUSH_DELAYED_ITEMS_NR;
5121                         if (commit_cycles)
5122                                 commit_cycles--;
5123                 }
5124
5125                 if (flush_state > COMMIT_TRANS) {
5126                         commit_cycles++;
5127                         if (commit_cycles > 2) {
5128                                 wake_all_tickets(&space_info->tickets);
5129                                 space_info->flush = 0;
5130                         } else {
5131                                 flush_state = FLUSH_DELAYED_ITEMS_NR;
5132                         }
5133                 }
5134                 spin_unlock(&space_info->lock);
5135         } while (flush_state <= COMMIT_TRANS);
5136 }
5137
5138 void btrfs_init_async_reclaim_work(struct work_struct *work)
5139 {
5140         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5141 }
5142
5143 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5144                                             struct btrfs_space_info *space_info,
5145                                             struct reserve_ticket *ticket)
5146 {
5147         u64 to_reclaim;
5148         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5149
5150         spin_lock(&space_info->lock);
5151         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5152                                                       false);
5153         if (!to_reclaim) {
5154                 spin_unlock(&space_info->lock);
5155                 return;
5156         }
5157         spin_unlock(&space_info->lock);
5158
5159         do {
5160                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5161                 flush_state++;
5162                 spin_lock(&space_info->lock);
5163                 if (ticket->bytes == 0) {
5164                         spin_unlock(&space_info->lock);
5165                         return;
5166                 }
5167                 spin_unlock(&space_info->lock);
5168
5169                 /*
5170                  * Priority flushers can't wait on delalloc without
5171                  * deadlocking.
5172                  */
5173                 if (flush_state == FLUSH_DELALLOC ||
5174                     flush_state == FLUSH_DELALLOC_WAIT)
5175                         flush_state = ALLOC_CHUNK;
5176         } while (flush_state < COMMIT_TRANS);
5177 }
5178
5179 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5180                                struct btrfs_space_info *space_info,
5181                                struct reserve_ticket *ticket, u64 orig_bytes)
5182
5183 {
5184         DEFINE_WAIT(wait);
5185         int ret = 0;
5186
5187         spin_lock(&space_info->lock);
5188         while (ticket->bytes > 0 && ticket->error == 0) {
5189                 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5190                 if (ret) {
5191                         ret = -EINTR;
5192                         break;
5193                 }
5194                 spin_unlock(&space_info->lock);
5195
5196                 schedule();
5197
5198                 finish_wait(&ticket->wait, &wait);
5199                 spin_lock(&space_info->lock);
5200         }
5201         if (!ret)
5202                 ret = ticket->error;
5203         if (!list_empty(&ticket->list))
5204                 list_del_init(&ticket->list);
5205         if (ticket->bytes && ticket->bytes < orig_bytes) {
5206                 u64 num_bytes = orig_bytes - ticket->bytes;
5207                 space_info->bytes_may_use -= num_bytes;
5208                 trace_btrfs_space_reservation(fs_info, "space_info",
5209                                               space_info->flags, num_bytes, 0);
5210         }
5211         spin_unlock(&space_info->lock);
5212
5213         return ret;
5214 }
5215
5216 /**
5217  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5218  * @root - the root we're allocating for
5219  * @space_info - the space info we want to allocate from
5220  * @orig_bytes - the number of bytes we want
5221  * @flush - whether or not we can flush to make our reservation
5222  *
5223  * This will reserve orig_bytes number of bytes from the space info associated
5224  * with the block_rsv.  If there is not enough space it will make an attempt to
5225  * flush out space to make room.  It will do this by flushing delalloc if
5226  * possible or committing the transaction.  If flush is 0 then no attempts to
5227  * regain reservations will be made and this will fail if there is not enough
5228  * space already.
5229  */
5230 static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
5231                                     struct btrfs_space_info *space_info,
5232                                     u64 orig_bytes,
5233                                     enum btrfs_reserve_flush_enum flush,
5234                                     bool system_chunk)
5235 {
5236         struct reserve_ticket ticket;
5237         u64 used;
5238         int ret = 0;
5239
5240         ASSERT(orig_bytes);
5241         ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5242
5243         spin_lock(&space_info->lock);
5244         ret = -ENOSPC;
5245         used = btrfs_space_info_used(space_info, true);
5246
5247         /*
5248          * If we have enough space then hooray, make our reservation and carry
5249          * on.  If not see if we can overcommit, and if we can, hooray carry on.
5250          * If not things get more complicated.
5251          */
5252         if (used + orig_bytes <= space_info->total_bytes) {
5253                 space_info->bytes_may_use += orig_bytes;
5254                 trace_btrfs_space_reservation(fs_info, "space_info",
5255                                               space_info->flags, orig_bytes, 1);
5256                 ret = 0;
5257         } else if (can_overcommit(fs_info, space_info, orig_bytes, flush,
5258                                   system_chunk)) {
5259                 space_info->bytes_may_use += orig_bytes;
5260                 trace_btrfs_space_reservation(fs_info, "space_info",
5261                                               space_info->flags, orig_bytes, 1);
5262                 ret = 0;
5263         }
5264
5265         /*
5266          * If we couldn't make a reservation then setup our reservation ticket
5267          * and kick the async worker if it's not already running.
5268          *
5269          * If we are a priority flusher then we just need to add our ticket to
5270          * the list and we will do our own flushing further down.
5271          */
5272         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5273                 ticket.bytes = orig_bytes;
5274                 ticket.error = 0;
5275                 init_waitqueue_head(&ticket.wait);
5276                 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5277                         list_add_tail(&ticket.list, &space_info->tickets);
5278                         if (!space_info->flush) {
5279                                 space_info->flush = 1;
5280                                 trace_btrfs_trigger_flush(fs_info,
5281                                                           space_info->flags,
5282                                                           orig_bytes, flush,
5283                                                           "enospc");
5284                                 queue_work(system_unbound_wq,
5285                                            &fs_info->async_reclaim_work);
5286                         }
5287                 } else {
5288                         list_add_tail(&ticket.list,
5289                                       &space_info->priority_tickets);
5290                 }
5291         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5292                 used += orig_bytes;
5293                 /*
5294                  * We will do the space reservation dance during log replay,
5295                  * which means we won't have fs_info->fs_root set, so don't do
5296                  * the async reclaim as we will panic.
5297                  */
5298                 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
5299                     need_do_async_reclaim(fs_info, space_info,
5300                                           used, system_chunk) &&
5301                     !work_busy(&fs_info->async_reclaim_work)) {
5302                         trace_btrfs_trigger_flush(fs_info, space_info->flags,
5303                                                   orig_bytes, flush, "preempt");
5304                         queue_work(system_unbound_wq,
5305                                    &fs_info->async_reclaim_work);
5306                 }
5307         }
5308         spin_unlock(&space_info->lock);
5309         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5310                 return ret;
5311
5312         if (flush == BTRFS_RESERVE_FLUSH_ALL)
5313                 return wait_reserve_ticket(fs_info, space_info, &ticket,
5314                                            orig_bytes);
5315
5316         ret = 0;
5317         priority_reclaim_metadata_space(fs_info, space_info, &ticket);
5318         spin_lock(&space_info->lock);
5319         if (ticket.bytes) {
5320                 if (ticket.bytes < orig_bytes) {
5321                         u64 num_bytes = orig_bytes - ticket.bytes;
5322                         space_info->bytes_may_use -= num_bytes;
5323                         trace_btrfs_space_reservation(fs_info, "space_info",
5324                                                       space_info->flags,
5325                                                       num_bytes, 0);
5326
5327                 }
5328                 list_del_init(&ticket.list);
5329                 ret = -ENOSPC;
5330         }
5331         spin_unlock(&space_info->lock);
5332         ASSERT(list_empty(&ticket.list));
5333         return ret;
5334 }
5335
5336 /**
5337  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5338  * @root - the root we're allocating for
5339  * @block_rsv - the block_rsv we're allocating for
5340  * @orig_bytes - the number of bytes we want
5341  * @flush - whether or not we can flush to make our reservation
5342  *
5343  * This will reserve orgi_bytes number of bytes from the space info associated
5344  * with the block_rsv.  If there is not enough space it will make an attempt to
5345  * flush out space to make room.  It will do this by flushing delalloc if
5346  * possible or committing the transaction.  If flush is 0 then no attempts to
5347  * regain reservations will be made and this will fail if there is not enough
5348  * space already.
5349  */
5350 static int reserve_metadata_bytes(struct btrfs_root *root,
5351                                   struct btrfs_block_rsv *block_rsv,
5352                                   u64 orig_bytes,
5353                                   enum btrfs_reserve_flush_enum flush)
5354 {
5355         struct btrfs_fs_info *fs_info = root->fs_info;
5356         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5357         int ret;
5358         bool system_chunk = (root == fs_info->chunk_root);
5359
5360         ret = __reserve_metadata_bytes(fs_info, block_rsv->space_info,
5361                                        orig_bytes, flush, system_chunk);
5362         if (ret == -ENOSPC &&
5363             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5364                 if (block_rsv != global_rsv &&
5365                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5366                         ret = 0;
5367         }
5368         if (ret == -ENOSPC) {
5369                 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
5370                                               block_rsv->space_info->flags,
5371                                               orig_bytes, 1);
5372
5373                 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG))
5374                         dump_space_info(fs_info, block_rsv->space_info,
5375                                         orig_bytes, 0);
5376         }
5377         return ret;
5378 }
5379
5380 static struct btrfs_block_rsv *get_block_rsv(
5381                                         const struct btrfs_trans_handle *trans,
5382                                         const struct btrfs_root *root)
5383 {
5384         struct btrfs_fs_info *fs_info = root->fs_info;
5385         struct btrfs_block_rsv *block_rsv = NULL;
5386
5387         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5388             (root == fs_info->csum_root && trans->adding_csums) ||
5389             (root == fs_info->uuid_root))
5390                 block_rsv = trans->block_rsv;
5391
5392         if (!block_rsv)
5393                 block_rsv = root->block_rsv;
5394
5395         if (!block_rsv)
5396                 block_rsv = &fs_info->empty_block_rsv;
5397
5398         return block_rsv;
5399 }
5400
5401 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5402                                u64 num_bytes)
5403 {
5404         int ret = -ENOSPC;
5405         spin_lock(&block_rsv->lock);
5406         if (block_rsv->reserved >= num_bytes) {
5407                 block_rsv->reserved -= num_bytes;
5408                 if (block_rsv->reserved < block_rsv->size)
5409                         block_rsv->full = 0;
5410                 ret = 0;
5411         }
5412         spin_unlock(&block_rsv->lock);
5413         return ret;
5414 }
5415
5416 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5417                                 u64 num_bytes, int update_size)
5418 {
5419         spin_lock(&block_rsv->lock);
5420         block_rsv->reserved += num_bytes;
5421         if (update_size)
5422                 block_rsv->size += num_bytes;
5423         else if (block_rsv->reserved >= block_rsv->size)
5424                 block_rsv->full = 1;
5425         spin_unlock(&block_rsv->lock);
5426 }
5427
5428 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5429                              struct btrfs_block_rsv *dest, u64 num_bytes,
5430                              int min_factor)
5431 {
5432         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5433         u64 min_bytes;
5434
5435         if (global_rsv->space_info != dest->space_info)
5436                 return -ENOSPC;
5437
5438         spin_lock(&global_rsv->lock);
5439         min_bytes = div_factor(global_rsv->size, min_factor);
5440         if (global_rsv->reserved < min_bytes + num_bytes) {
5441                 spin_unlock(&global_rsv->lock);
5442                 return -ENOSPC;
5443         }
5444         global_rsv->reserved -= num_bytes;
5445         if (global_rsv->reserved < global_rsv->size)
5446                 global_rsv->full = 0;
5447         spin_unlock(&global_rsv->lock);
5448
5449         block_rsv_add_bytes(dest, num_bytes, 1);
5450         return 0;
5451 }
5452
5453 /*
5454  * This is for space we already have accounted in space_info->bytes_may_use, so
5455  * basically when we're returning space from block_rsv's.
5456  */
5457 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5458                                      struct btrfs_space_info *space_info,
5459                                      u64 num_bytes)
5460 {
5461         struct reserve_ticket *ticket;
5462         struct list_head *head;
5463         u64 used;
5464         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5465         bool check_overcommit = false;
5466
5467         spin_lock(&space_info->lock);
5468         head = &space_info->priority_tickets;
5469
5470         /*
5471          * If we are over our limit then we need to check and see if we can
5472          * overcommit, and if we can't then we just need to free up our space
5473          * and not satisfy any requests.
5474          */
5475         used = btrfs_space_info_used(space_info, true);
5476         if (used - num_bytes >= space_info->total_bytes)
5477                 check_overcommit = true;
5478 again:
5479         while (!list_empty(head) && num_bytes) {
5480                 ticket = list_first_entry(head, struct reserve_ticket,
5481                                           list);
5482                 /*
5483                  * We use 0 bytes because this space is already reserved, so
5484                  * adding the ticket space would be a double count.
5485                  */
5486                 if (check_overcommit &&
5487                     !can_overcommit(fs_info, space_info, 0, flush, false))
5488                         break;
5489                 if (num_bytes >= ticket->bytes) {
5490                         list_del_init(&ticket->list);
5491                         num_bytes -= ticket->bytes;
5492                         ticket->bytes = 0;
5493                         space_info->tickets_id++;
5494                         wake_up(&ticket->wait);
5495                 } else {
5496                         ticket->bytes -= num_bytes;
5497                         num_bytes = 0;
5498                 }
5499         }
5500
5501         if (num_bytes && head == &space_info->priority_tickets) {
5502                 head = &space_info->tickets;
5503                 flush = BTRFS_RESERVE_FLUSH_ALL;
5504                 goto again;
5505         }
5506         space_info->bytes_may_use -= num_bytes;
5507         trace_btrfs_space_reservation(fs_info, "space_info",
5508                                       space_info->flags, num_bytes, 0);
5509         spin_unlock(&space_info->lock);
5510 }
5511
5512 /*
5513  * This is for newly allocated space that isn't accounted in
5514  * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
5515  * we use this helper.
5516  */
5517 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5518                                      struct btrfs_space_info *space_info,
5519                                      u64 num_bytes)
5520 {
5521         struct reserve_ticket *ticket;
5522         struct list_head *head = &space_info->priority_tickets;
5523
5524 again:
5525         while (!list_empty(head) && num_bytes) {
5526                 ticket = list_first_entry(head, struct reserve_ticket,
5527                                           list);
5528                 if (num_bytes >= ticket->bytes) {
5529                         trace_btrfs_space_reservation(fs_info, "space_info",
5530                                                       space_info->flags,
5531                                                       ticket->bytes, 1);
5532                         list_del_init(&ticket->list);
5533                         num_bytes -= ticket->bytes;
5534                         space_info->bytes_may_use += ticket->bytes;
5535                         ticket->bytes = 0;
5536                         space_info->tickets_id++;
5537                         wake_up(&ticket->wait);
5538                 } else {
5539                         trace_btrfs_space_reservation(fs_info, "space_info",
5540                                                       space_info->flags,
5541                                                       num_bytes, 1);
5542                         space_info->bytes_may_use += num_bytes;
5543                         ticket->bytes -= num_bytes;
5544                         num_bytes = 0;
5545                 }
5546         }
5547
5548         if (num_bytes && head == &space_info->priority_tickets) {
5549                 head = &space_info->tickets;
5550                 goto again;
5551         }
5552 }
5553
5554 static u64 block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5555                                     struct btrfs_block_rsv *block_rsv,
5556                                     struct btrfs_block_rsv *dest, u64 num_bytes,
5557                                     u64 *qgroup_to_release_ret)
5558 {
5559         struct btrfs_space_info *space_info = block_rsv->space_info;
5560         u64 qgroup_to_release = 0;
5561         u64 ret;
5562
5563         spin_lock(&block_rsv->lock);
5564         if (num_bytes == (u64)-1) {
5565                 num_bytes = block_rsv->size;
5566                 qgroup_to_release = block_rsv->qgroup_rsv_size;
5567         }
5568         block_rsv->size -= num_bytes;
5569         if (block_rsv->reserved >= block_rsv->size) {
5570                 num_bytes = block_rsv->reserved - block_rsv->size;
5571                 block_rsv->reserved = block_rsv->size;
5572                 block_rsv->full = 1;
5573         } else {
5574                 num_bytes = 0;
5575         }
5576         if (block_rsv->qgroup_rsv_reserved >= block_rsv->qgroup_rsv_size) {
5577                 qgroup_to_release = block_rsv->qgroup_rsv_reserved -
5578                                     block_rsv->qgroup_rsv_size;
5579                 block_rsv->qgroup_rsv_reserved = block_rsv->qgroup_rsv_size;
5580         } else {
5581                 qgroup_to_release = 0;
5582         }
5583         spin_unlock(&block_rsv->lock);
5584
5585         ret = num_bytes;
5586         if (num_bytes > 0) {
5587                 if (dest) {
5588                         spin_lock(&dest->lock);
5589                         if (!dest->full) {
5590                                 u64 bytes_to_add;
5591
5592                                 bytes_to_add = dest->size - dest->reserved;
5593                                 bytes_to_add = min(num_bytes, bytes_to_add);
5594                                 dest->reserved += bytes_to_add;
5595                                 if (dest->reserved >= dest->size)
5596                                         dest->full = 1;
5597                                 num_bytes -= bytes_to_add;
5598                         }
5599                         spin_unlock(&dest->lock);
5600                 }
5601                 if (num_bytes)
5602                         space_info_add_old_bytes(fs_info, space_info,
5603                                                  num_bytes);
5604         }
5605         if (qgroup_to_release_ret)
5606                 *qgroup_to_release_ret = qgroup_to_release;
5607         return ret;
5608 }
5609
5610 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5611                             struct btrfs_block_rsv *dst, u64 num_bytes,
5612                             int update_size)
5613 {
5614         int ret;
5615
5616         ret = block_rsv_use_bytes(src, num_bytes);
5617         if (ret)
5618                 return ret;
5619
5620         block_rsv_add_bytes(dst, num_bytes, update_size);
5621         return 0;
5622 }
5623
5624 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5625 {
5626         memset(rsv, 0, sizeof(*rsv));
5627         spin_lock_init(&rsv->lock);
5628         rsv->type = type;
5629 }
5630
5631 void btrfs_init_metadata_block_rsv(struct btrfs_fs_info *fs_info,
5632                                    struct btrfs_block_rsv *rsv,
5633                                    unsigned short type)
5634 {
5635         btrfs_init_block_rsv(rsv, type);
5636         rsv->space_info = __find_space_info(fs_info,
5637                                             BTRFS_BLOCK_GROUP_METADATA);
5638 }
5639
5640 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
5641                                               unsigned short type)
5642 {
5643         struct btrfs_block_rsv *block_rsv;
5644
5645         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5646         if (!block_rsv)
5647                 return NULL;
5648
5649         btrfs_init_metadata_block_rsv(fs_info, block_rsv, type);
5650         return block_rsv;
5651 }
5652
5653 void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
5654                           struct btrfs_block_rsv *rsv)
5655 {
5656         if (!rsv)
5657                 return;
5658         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5659         kfree(rsv);
5660 }
5661
5662 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5663 {
5664         kfree(rsv);
5665 }
5666
5667 int btrfs_block_rsv_add(struct btrfs_root *root,
5668                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5669                         enum btrfs_reserve_flush_enum flush)
5670 {
5671         int ret;
5672
5673         if (num_bytes == 0)
5674                 return 0;
5675
5676         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5677         if (!ret) {
5678                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5679                 return 0;
5680         }
5681
5682         return ret;
5683 }
5684
5685 int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
5686 {
5687         u64 num_bytes = 0;
5688         int ret = -ENOSPC;
5689
5690         if (!block_rsv)
5691                 return 0;
5692
5693         spin_lock(&block_rsv->lock);
5694         num_bytes = div_factor(block_rsv->size, min_factor);
5695         if (block_rsv->reserved >= num_bytes)
5696                 ret = 0;
5697         spin_unlock(&block_rsv->lock);
5698
5699         return ret;
5700 }
5701
5702 int btrfs_block_rsv_refill(struct btrfs_root *root,
5703                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5704                            enum btrfs_reserve_flush_enum flush)
5705 {
5706         u64 num_bytes = 0;
5707         int ret = -ENOSPC;
5708
5709         if (!block_rsv)
5710                 return 0;
5711
5712         spin_lock(&block_rsv->lock);
5713         num_bytes = min_reserved;
5714         if (block_rsv->reserved >= num_bytes)
5715                 ret = 0;
5716         else
5717                 num_bytes -= block_rsv->reserved;
5718         spin_unlock(&block_rsv->lock);
5719
5720         if (!ret)
5721                 return 0;
5722
5723         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5724         if (!ret) {
5725                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5726                 return 0;
5727         }
5728
5729         return ret;
5730 }
5731
5732 /**
5733  * btrfs_inode_rsv_refill - refill the inode block rsv.
5734  * @inode - the inode we are refilling.
5735  * @flush - the flusing restriction.
5736  *
5737  * Essentially the same as btrfs_block_rsv_refill, except it uses the
5738  * block_rsv->size as the minimum size.  We'll either refill the missing amount
5739  * or return if we already have enough space.  This will also handle the resreve
5740  * tracepoint for the reserved amount.
5741  */
5742 static int btrfs_inode_rsv_refill(struct btrfs_inode *inode,
5743                                   enum btrfs_reserve_flush_enum flush)
5744 {
5745         struct btrfs_root *root = inode->root;
5746         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5747         u64 num_bytes = 0;
5748         u64 qgroup_num_bytes = 0;
5749         int ret = -ENOSPC;
5750
5751         spin_lock(&block_rsv->lock);
5752         if (block_rsv->reserved < block_rsv->size)
5753                 num_bytes = block_rsv->size - block_rsv->reserved;
5754         if (block_rsv->qgroup_rsv_reserved < block_rsv->qgroup_rsv_size)
5755                 qgroup_num_bytes = block_rsv->qgroup_rsv_size -
5756                                    block_rsv->qgroup_rsv_reserved;
5757         spin_unlock(&block_rsv->lock);
5758
5759         if (num_bytes == 0)
5760                 return 0;
5761
5762         ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_num_bytes, true);
5763         if (ret)
5764                 return ret;
5765         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5766         if (!ret) {
5767                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5768                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5769                                               btrfs_ino(inode), num_bytes, 1);
5770
5771                 /* Don't forget to increase qgroup_rsv_reserved */
5772                 spin_lock(&block_rsv->lock);
5773                 block_rsv->qgroup_rsv_reserved += qgroup_num_bytes;
5774                 spin_unlock(&block_rsv->lock);
5775         } else
5776                 btrfs_qgroup_free_meta_prealloc(root, qgroup_num_bytes);
5777         return ret;
5778 }
5779
5780 /**
5781  * btrfs_inode_rsv_release - release any excessive reservation.
5782  * @inode - the inode we need to release from.
5783  * @qgroup_free - free or convert qgroup meta.
5784  *   Unlike normal operation, qgroup meta reservation needs to know if we are
5785  *   freeing qgroup reservation or just converting it into per-trans.  Normally
5786  *   @qgroup_free is true for error handling, and false for normal release.
5787  *
5788  * This is the same as btrfs_block_rsv_release, except that it handles the
5789  * tracepoint for the reservation.
5790  */
5791 static void btrfs_inode_rsv_release(struct btrfs_inode *inode, bool qgroup_free)
5792 {
5793         struct btrfs_fs_info *fs_info = inode->root->fs_info;
5794         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5795         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5796         u64 released = 0;
5797         u64 qgroup_to_release = 0;
5798
5799         /*
5800          * Since we statically set the block_rsv->size we just want to say we
5801          * are releasing 0 bytes, and then we'll just get the reservation over
5802          * the size free'd.
5803          */
5804         released = block_rsv_release_bytes(fs_info, block_rsv, global_rsv, 0,
5805                                            &qgroup_to_release);
5806         if (released > 0)
5807                 trace_btrfs_space_reservation(fs_info, "delalloc",
5808                                               btrfs_ino(inode), released, 0);
5809         if (qgroup_free)
5810                 btrfs_qgroup_free_meta_prealloc(inode->root, qgroup_to_release);
5811         else
5812                 btrfs_qgroup_convert_reserved_meta(inode->root,
5813                                                    qgroup_to_release);
5814 }
5815
5816 void btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
5817                              struct btrfs_block_rsv *block_rsv,
5818                              u64 num_bytes)
5819 {
5820         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5821
5822         if (global_rsv == block_rsv ||
5823             block_rsv->space_info != global_rsv->space_info)
5824                 global_rsv = NULL;
5825         block_rsv_release_bytes(fs_info, block_rsv, global_rsv, num_bytes, NULL);
5826 }
5827
5828 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5829 {
5830         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5831         struct btrfs_space_info *sinfo = block_rsv->space_info;
5832         u64 num_bytes;
5833
5834         /*
5835          * The global block rsv is based on the size of the extent tree, the
5836          * checksum tree and the root tree.  If the fs is empty we want to set
5837          * it to a minimal amount for safety.
5838          */
5839         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5840                 btrfs_root_used(&fs_info->csum_root->root_item) +
5841                 btrfs_root_used(&fs_info->tree_root->root_item);
5842         num_bytes = max_t(u64, num_bytes, SZ_16M);
5843
5844         spin_lock(&sinfo->lock);
5845         spin_lock(&block_rsv->lock);
5846
5847         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5848
5849         if (block_rsv->reserved < block_rsv->size) {
5850                 num_bytes = btrfs_space_info_used(sinfo, true);
5851                 if (sinfo->total_bytes > num_bytes) {
5852                         num_bytes = sinfo->total_bytes - num_bytes;
5853                         num_bytes = min(num_bytes,
5854                                         block_rsv->size - block_rsv->reserved);
5855                         block_rsv->reserved += num_bytes;
5856                         sinfo->bytes_may_use += num_bytes;
5857                         trace_btrfs_space_reservation(fs_info, "space_info",
5858                                                       sinfo->flags, num_bytes,
5859                                                       1);
5860                 }
5861         } else if (block_rsv->reserved > block_rsv->size) {
5862                 num_bytes = block_rsv->reserved - block_rsv->size;
5863                 sinfo->bytes_may_use -= num_bytes;
5864                 trace_btrfs_space_reservation(fs_info, "space_info",
5865                                       sinfo->flags, num_bytes, 0);
5866                 block_rsv->reserved = block_rsv->size;
5867         }
5868
5869         if (block_rsv->reserved == block_rsv->size)
5870                 block_rsv->full = 1;
5871         else
5872                 block_rsv->full = 0;
5873
5874         spin_unlock(&block_rsv->lock);
5875         spin_unlock(&sinfo->lock);
5876 }
5877
5878 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5879 {
5880         struct btrfs_space_info *space_info;
5881
5882         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5883         fs_info->chunk_block_rsv.space_info = space_info;
5884
5885         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5886         fs_info->global_block_rsv.space_info = space_info;
5887         fs_info->trans_block_rsv.space_info = space_info;
5888         fs_info->empty_block_rsv.space_info = space_info;
5889         fs_info->delayed_block_rsv.space_info = space_info;
5890
5891         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5892         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5893         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5894         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5895         if (fs_info->quota_root)
5896                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5897         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5898
5899         update_global_block_rsv(fs_info);
5900 }
5901
5902 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5903 {
5904         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5905                                 (u64)-1, NULL);
5906         WARN_ON(fs_info->trans_block_rsv.size > 0);
5907         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5908         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5909         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5910         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5911         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5912 }
5913
5914
5915 /*
5916  * To be called after all the new block groups attached to the transaction
5917  * handle have been created (btrfs_create_pending_block_groups()).
5918  */
5919 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5920 {
5921         struct btrfs_fs_info *fs_info = trans->fs_info;
5922
5923         if (!trans->chunk_bytes_reserved)
5924                 return;
5925
5926         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5927
5928         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5929                                 trans->chunk_bytes_reserved, NULL);
5930         trans->chunk_bytes_reserved = 0;
5931 }
5932
5933 /*
5934  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5935  * root: the root of the parent directory
5936  * rsv: block reservation
5937  * items: the number of items that we need do reservation
5938  * qgroup_reserved: used to return the reserved size in qgroup
5939  *
5940  * This function is used to reserve the space for snapshot/subvolume
5941  * creation and deletion. Those operations are different with the
5942  * common file/directory operations, they change two fs/file trees
5943  * and root tree, the number of items that the qgroup reserves is
5944  * different with the free space reservation. So we can not use
5945  * the space reservation mechanism in start_transaction().
5946  */
5947 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5948                                      struct btrfs_block_rsv *rsv,
5949                                      int items,
5950                                      bool use_global_rsv)
5951 {
5952         u64 num_bytes;
5953         int ret;
5954         struct btrfs_fs_info *fs_info = root->fs_info;
5955         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5956
5957         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
5958                 /* One for parent inode, two for dir entries */
5959                 num_bytes = 3 * fs_info->nodesize;
5960                 ret = btrfs_qgroup_reserve_meta_prealloc(root, num_bytes, true);
5961                 if (ret)
5962                         return ret;
5963         } else {
5964                 num_bytes = 0;
5965         }
5966
5967         num_bytes = btrfs_calc_trans_metadata_size(fs_info, items);
5968         rsv->space_info = __find_space_info(fs_info,
5969                                             BTRFS_BLOCK_GROUP_METADATA);
5970         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5971                                   BTRFS_RESERVE_FLUSH_ALL);
5972
5973         if (ret == -ENOSPC && use_global_rsv)
5974                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5975
5976         if (ret && num_bytes)
5977                 btrfs_qgroup_free_meta_prealloc(root, num_bytes);
5978
5979         return ret;
5980 }
5981
5982 void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
5983                                       struct btrfs_block_rsv *rsv)
5984 {
5985         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5986 }
5987
5988 static void btrfs_calculate_inode_block_rsv_size(struct btrfs_fs_info *fs_info,
5989                                                  struct btrfs_inode *inode)
5990 {
5991         struct btrfs_block_rsv *block_rsv = &inode->block_rsv;
5992         u64 reserve_size = 0;
5993         u64 qgroup_rsv_size = 0;
5994         u64 csum_leaves;
5995         unsigned outstanding_extents;
5996
5997         lockdep_assert_held(&inode->lock);
5998         outstanding_extents = inode->outstanding_extents;
5999         if (outstanding_extents)
6000                 reserve_size = btrfs_calc_trans_metadata_size(fs_info,
6001                                                 outstanding_extents + 1);
6002         csum_leaves = btrfs_csum_bytes_to_leaves(fs_info,
6003                                                  inode->csum_bytes);
6004         reserve_size += btrfs_calc_trans_metadata_size(fs_info,
6005                                                        csum_leaves);
6006         /*
6007          * For qgroup rsv, the calculation is very simple:
6008          * account one nodesize for each outstanding extent
6009          *
6010          * This is overestimating in most cases.
6011          */
6012         qgroup_rsv_size = outstanding_extents * fs_info->nodesize;
6013
6014         spin_lock(&block_rsv->lock);
6015         block_rsv->size = reserve_size;
6016         block_rsv->qgroup_rsv_size = qgroup_rsv_size;
6017         spin_unlock(&block_rsv->lock);
6018 }
6019
6020 int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
6021 {
6022         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6023         unsigned nr_extents;
6024         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
6025         int ret = 0;
6026         bool delalloc_lock = true;
6027
6028         /* If we are a free space inode we need to not flush since we will be in
6029          * the middle of a transaction commit.  We also don't need the delalloc
6030          * mutex since we won't race with anybody.  We need this mostly to make
6031          * lockdep shut its filthy mouth.
6032          *
6033          * If we have a transaction open (can happen if we call truncate_block
6034          * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
6035          */
6036         if (btrfs_is_free_space_inode(inode)) {
6037                 flush = BTRFS_RESERVE_NO_FLUSH;
6038                 delalloc_lock = false;
6039         } else {
6040                 if (current->journal_info)
6041                         flush = BTRFS_RESERVE_FLUSH_LIMIT;
6042
6043                 if (btrfs_transaction_in_commit(fs_info))
6044                         schedule_timeout(1);
6045         }
6046
6047         if (delalloc_lock)
6048                 mutex_lock(&inode->delalloc_mutex);
6049
6050         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
6051
6052         /* Add our new extents and calculate the new rsv size. */
6053         spin_lock(&inode->lock);
6054         nr_extents = count_max_extents(num_bytes);
6055         btrfs_mod_outstanding_extents(inode, nr_extents);
6056         inode->csum_bytes += num_bytes;
6057         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6058         spin_unlock(&inode->lock);
6059
6060         ret = btrfs_inode_rsv_refill(inode, flush);
6061         if (unlikely(ret))
6062                 goto out_fail;
6063
6064         if (delalloc_lock)
6065                 mutex_unlock(&inode->delalloc_mutex);
6066         return 0;
6067
6068 out_fail:
6069         spin_lock(&inode->lock);
6070         nr_extents = count_max_extents(num_bytes);
6071         btrfs_mod_outstanding_extents(inode, -nr_extents);
6072         inode->csum_bytes -= num_bytes;
6073         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6074         spin_unlock(&inode->lock);
6075
6076         btrfs_inode_rsv_release(inode, true);
6077         if (delalloc_lock)
6078                 mutex_unlock(&inode->delalloc_mutex);
6079         return ret;
6080 }
6081
6082 /**
6083  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6084  * @inode: the inode to release the reservation for.
6085  * @num_bytes: the number of bytes we are releasing.
6086  * @qgroup_free: free qgroup reservation or convert it to per-trans reservation
6087  *
6088  * This will release the metadata reservation for an inode.  This can be called
6089  * once we complete IO for a given set of bytes to release their metadata
6090  * reservations, or on error for the same reason.
6091  */
6092 void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes,
6093                                      bool qgroup_free)
6094 {
6095         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6096
6097         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
6098         spin_lock(&inode->lock);
6099         inode->csum_bytes -= num_bytes;
6100         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6101         spin_unlock(&inode->lock);
6102
6103         if (btrfs_is_testing(fs_info))
6104                 return;
6105
6106         btrfs_inode_rsv_release(inode, qgroup_free);
6107 }
6108
6109 /**
6110  * btrfs_delalloc_release_extents - release our outstanding_extents
6111  * @inode: the inode to balance the reservation for.
6112  * @num_bytes: the number of bytes we originally reserved with
6113  * @qgroup_free: do we need to free qgroup meta reservation or convert them.
6114  *
6115  * When we reserve space we increase outstanding_extents for the extents we may
6116  * add.  Once we've set the range as delalloc or created our ordered extents we
6117  * have outstanding_extents to track the real usage, so we use this to free our
6118  * temporarily tracked outstanding_extents.  This _must_ be used in conjunction
6119  * with btrfs_delalloc_reserve_metadata.
6120  */
6121 void btrfs_delalloc_release_extents(struct btrfs_inode *inode, u64 num_bytes,
6122                                     bool qgroup_free)
6123 {
6124         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6125         unsigned num_extents;
6126
6127         spin_lock(&inode->lock);
6128         num_extents = count_max_extents(num_bytes);
6129         btrfs_mod_outstanding_extents(inode, -num_extents);
6130         btrfs_calculate_inode_block_rsv_size(fs_info, inode);
6131         spin_unlock(&inode->lock);
6132
6133         if (btrfs_is_testing(fs_info))
6134                 return;
6135
6136         btrfs_inode_rsv_release(inode, qgroup_free);
6137 }
6138
6139 /**
6140  * btrfs_delalloc_reserve_space - reserve data and metadata space for
6141  * delalloc
6142  * @inode: inode we're writing to
6143  * @start: start range we are writing to
6144  * @len: how long the range we are writing to
6145  * @reserved: mandatory parameter, record actually reserved qgroup ranges of
6146  *            current reservation.
6147  *
6148  * This will do the following things
6149  *
6150  * o reserve space in data space info for num bytes
6151  *   and reserve precious corresponding qgroup space
6152  *   (Done in check_data_free_space)
6153  *
6154  * o reserve space for metadata space, based on the number of outstanding
6155  *   extents and how much csums will be needed
6156  *   also reserve metadata space in a per root over-reserve method.
6157  * o add to the inodes->delalloc_bytes
6158  * o add it to the fs_info's delalloc inodes list.
6159  *   (Above 3 all done in delalloc_reserve_metadata)
6160  *
6161  * Return 0 for success
6162  * Return <0 for error(-ENOSPC or -EQUOT)
6163  */
6164 int btrfs_delalloc_reserve_space(struct inode *inode,
6165                         struct extent_changeset **reserved, u64 start, u64 len)
6166 {
6167         int ret;
6168
6169         ret = btrfs_check_data_free_space(inode, reserved, start, len);
6170         if (ret < 0)
6171                 return ret;
6172         ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len);
6173         if (ret < 0)
6174                 btrfs_free_reserved_data_space(inode, *reserved, start, len);
6175         return ret;
6176 }
6177
6178 /**
6179  * btrfs_delalloc_release_space - release data and metadata space for delalloc
6180  * @inode: inode we're releasing space for
6181  * @start: start position of the space already reserved
6182  * @len: the len of the space already reserved
6183  * @release_bytes: the len of the space we consumed or didn't use
6184  *
6185  * This function will release the metadata space that was not used and will
6186  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6187  * list if there are no delalloc bytes left.
6188  * Also it will handle the qgroup reserved space.
6189  */
6190 void btrfs_delalloc_release_space(struct inode *inode,
6191                                   struct extent_changeset *reserved,
6192                                   u64 start, u64 len, bool qgroup_free)
6193 {
6194         btrfs_delalloc_release_metadata(BTRFS_I(inode), len, qgroup_free);
6195         btrfs_free_reserved_data_space(inode, reserved, start, len);
6196 }
6197
6198 static int update_block_group(struct btrfs_trans_handle *trans,
6199                               struct btrfs_fs_info *info, u64 bytenr,
6200                               u64 num_bytes, int alloc)
6201 {
6202         struct btrfs_block_group_cache *cache = NULL;
6203         u64 total = num_bytes;
6204         u64 old_val;
6205         u64 byte_in_group;
6206         int factor;
6207
6208         /* block accounting for super block */
6209         spin_lock(&info->delalloc_root_lock);
6210         old_val = btrfs_super_bytes_used(info->super_copy);
6211         if (alloc)
6212                 old_val += num_bytes;
6213         else
6214                 old_val -= num_bytes;
6215         btrfs_set_super_bytes_used(info->super_copy, old_val);
6216         spin_unlock(&info->delalloc_root_lock);
6217
6218         while (total) {
6219                 cache = btrfs_lookup_block_group(info, bytenr);
6220                 if (!cache)
6221                         return -ENOENT;
6222                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6223                                     BTRFS_BLOCK_GROUP_RAID1 |
6224                                     BTRFS_BLOCK_GROUP_RAID10))
6225                         factor = 2;
6226                 else
6227                         factor = 1;
6228                 /*
6229                  * If this block group has free space cache written out, we
6230                  * need to make sure to load it if we are removing space.  This
6231                  * is because we need the unpinning stage to actually add the
6232                  * space back to the block group, otherwise we will leak space.
6233                  */
6234                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6235                         cache_block_group(cache, 1);
6236
6237                 byte_in_group = bytenr - cache->key.objectid;
6238                 WARN_ON(byte_in_group > cache->key.offset);
6239
6240                 spin_lock(&cache->space_info->lock);
6241                 spin_lock(&cache->lock);
6242
6243                 if (btrfs_test_opt(info, SPACE_CACHE) &&
6244                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6245                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6246
6247                 old_val = btrfs_block_group_used(&cache->item);
6248                 num_bytes = min(total, cache->key.offset - byte_in_group);
6249                 if (alloc) {
6250                         old_val += num_bytes;
6251                         btrfs_set_block_group_used(&cache->item, old_val);
6252                         cache->reserved -= num_bytes;
6253                         cache->space_info->bytes_reserved -= num_bytes;
6254                         cache->space_info->bytes_used += num_bytes;
6255                         cache->space_info->disk_used += num_bytes * factor;
6256                         spin_unlock(&cache->lock);
6257                         spin_unlock(&cache->space_info->lock);
6258                 } else {
6259                         old_val -= num_bytes;
6260                         btrfs_set_block_group_used(&cache->item, old_val);
6261                         cache->pinned += num_bytes;
6262                         cache->space_info->bytes_pinned += num_bytes;
6263                         cache->space_info->bytes_used -= num_bytes;
6264                         cache->space_info->disk_used -= num_bytes * factor;
6265                         spin_unlock(&cache->lock);
6266                         spin_unlock(&cache->space_info->lock);
6267
6268                         trace_btrfs_space_reservation(info, "pinned",
6269                                                       cache->space_info->flags,
6270                                                       num_bytes, 1);
6271                         percpu_counter_add(&cache->space_info->total_bytes_pinned,
6272                                            num_bytes);
6273                         set_extent_dirty(info->pinned_extents,
6274                                          bytenr, bytenr + num_bytes - 1,
6275                                          GFP_NOFS | __GFP_NOFAIL);
6276                 }
6277
6278                 spin_lock(&trans->transaction->dirty_bgs_lock);
6279                 if (list_empty(&cache->dirty_list)) {
6280                         list_add_tail(&cache->dirty_list,
6281                                       &trans->transaction->dirty_bgs);
6282                                 trans->transaction->num_dirty_bgs++;
6283                         btrfs_get_block_group(cache);
6284                 }
6285                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6286
6287                 /*
6288                  * No longer have used bytes in this block group, queue it for
6289                  * deletion. We do this after adding the block group to the
6290                  * dirty list to avoid races between cleaner kthread and space
6291                  * cache writeout.
6292                  */
6293                 if (!alloc && old_val == 0) {
6294                         spin_lock(&info->unused_bgs_lock);
6295                         if (list_empty(&cache->bg_list)) {
6296                                 btrfs_get_block_group(cache);
6297                                 trace_btrfs_add_unused_block_group(cache);
6298                                 list_add_tail(&cache->bg_list,
6299                                               &info->unused_bgs);
6300                         }
6301                         spin_unlock(&info->unused_bgs_lock);
6302                 }
6303
6304                 btrfs_put_block_group(cache);
6305                 total -= num_bytes;
6306                 bytenr += num_bytes;
6307         }
6308         return 0;
6309 }
6310
6311 static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
6312 {
6313         struct btrfs_block_group_cache *cache;
6314         u64 bytenr;
6315
6316         spin_lock(&fs_info->block_group_cache_lock);
6317         bytenr = fs_info->first_logical_byte;
6318         spin_unlock(&fs_info->block_group_cache_lock);
6319
6320         if (bytenr < (u64)-1)
6321                 return bytenr;
6322
6323         cache = btrfs_lookup_first_block_group(fs_info, search_start);
6324         if (!cache)
6325                 return 0;
6326
6327         bytenr = cache->key.objectid;
6328         btrfs_put_block_group(cache);
6329
6330         return bytenr;
6331 }
6332
6333 static int pin_down_extent(struct btrfs_fs_info *fs_info,
6334                            struct btrfs_block_group_cache *cache,
6335                            u64 bytenr, u64 num_bytes, int reserved)
6336 {
6337         spin_lock(&cache->space_info->lock);
6338         spin_lock(&cache->lock);
6339         cache->pinned += num_bytes;
6340         cache->space_info->bytes_pinned += num_bytes;
6341         if (reserved) {
6342                 cache->reserved -= num_bytes;
6343                 cache->space_info->bytes_reserved -= num_bytes;
6344         }
6345         spin_unlock(&cache->lock);
6346         spin_unlock(&cache->space_info->lock);
6347
6348         trace_btrfs_space_reservation(fs_info, "pinned",
6349                                       cache->space_info->flags, num_bytes, 1);
6350         percpu_counter_add(&cache->space_info->total_bytes_pinned, num_bytes);
6351         set_extent_dirty(fs_info->pinned_extents, bytenr,
6352                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6353         return 0;
6354 }
6355
6356 /*
6357  * this function must be called within transaction
6358  */
6359 int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
6360                      u64 bytenr, u64 num_bytes, int reserved)
6361 {
6362         struct btrfs_block_group_cache *cache;
6363
6364         cache = btrfs_lookup_block_group(fs_info, bytenr);
6365         BUG_ON(!cache); /* Logic error */
6366
6367         pin_down_extent(fs_info, cache, bytenr, num_bytes, reserved);
6368
6369         btrfs_put_block_group(cache);
6370         return 0;
6371 }
6372
6373 /*
6374  * this function must be called within transaction
6375  */
6376 int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
6377                                     u64 bytenr, u64 num_bytes)
6378 {
6379         struct btrfs_block_group_cache *cache;
6380         int ret;
6381
6382         cache = btrfs_lookup_block_group(fs_info, bytenr);
6383         if (!cache)
6384                 return -EINVAL;
6385
6386         /*
6387          * pull in the free space cache (if any) so that our pin
6388          * removes the free space from the cache.  We have load_only set
6389          * to one because the slow code to read in the free extents does check
6390          * the pinned extents.
6391          */
6392         cache_block_group(cache, 1);
6393
6394         pin_down_extent(fs_info, cache, bytenr, num_bytes, 0);
6395
6396         /* remove us from the free space cache (if we're there at all) */
6397         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6398         btrfs_put_block_group(cache);
6399         return ret;
6400 }
6401
6402 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
6403                                    u64 start, u64 num_bytes)
6404 {
6405         int ret;
6406         struct btrfs_block_group_cache *block_group;
6407         struct btrfs_caching_control *caching_ctl;
6408
6409         block_group = btrfs_lookup_block_group(fs_info, start);
6410         if (!block_group)
6411                 return -EINVAL;
6412
6413         cache_block_group(block_group, 0);
6414         caching_ctl = get_caching_control(block_group);
6415
6416         if (!caching_ctl) {
6417                 /* Logic error */
6418                 BUG_ON(!block_group_cache_done(block_group));
6419                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6420         } else {
6421                 mutex_lock(&caching_ctl->mutex);
6422
6423                 if (start >= caching_ctl->progress) {
6424                         ret = add_excluded_extent(fs_info, start, num_bytes);
6425                 } else if (start + num_bytes <= caching_ctl->progress) {
6426                         ret = btrfs_remove_free_space(block_group,
6427                                                       start, num_bytes);
6428                 } else {
6429                         num_bytes = caching_ctl->progress - start;
6430                         ret = btrfs_remove_free_space(block_group,
6431                                                       start, num_bytes);
6432                         if (ret)
6433                                 goto out_lock;
6434
6435                         num_bytes = (start + num_bytes) -
6436                                 caching_ctl->progress;
6437                         start = caching_ctl->progress;
6438                         ret = add_excluded_extent(fs_info, start, num_bytes);
6439                 }
6440 out_lock:
6441                 mutex_unlock(&caching_ctl->mutex);
6442                 put_caching_control(caching_ctl);
6443         }
6444         btrfs_put_block_group(block_group);
6445         return ret;
6446 }
6447
6448 int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
6449                                  struct extent_buffer *eb)
6450 {
6451         struct btrfs_file_extent_item *item;
6452         struct btrfs_key key;
6453         int found_type;
6454         int i;
6455         int ret = 0;
6456
6457         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
6458                 return 0;
6459
6460         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6461                 btrfs_item_key_to_cpu(eb, &key, i);
6462                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6463                         continue;
6464                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6465                 found_type = btrfs_file_extent_type(eb, item);
6466                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6467                         continue;
6468                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6469                         continue;
6470                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6471                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6472                 ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
6473                 if (ret)
6474                         break;
6475         }
6476
6477         return ret;
6478 }
6479
6480 static void
6481 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6482 {
6483         atomic_inc(&bg->reservations);
6484 }
6485
6486 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6487                                         const u64 start)
6488 {
6489         struct btrfs_block_group_cache *bg;
6490
6491         bg = btrfs_lookup_block_group(fs_info, start);
6492         ASSERT(bg);
6493         if (atomic_dec_and_test(&bg->reservations))
6494                 wake_up_var(&bg->reservations);
6495         btrfs_put_block_group(bg);
6496 }
6497
6498 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6499 {
6500         struct btrfs_space_info *space_info = bg->space_info;
6501
6502         ASSERT(bg->ro);
6503
6504         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6505                 return;
6506
6507         /*
6508          * Our block group is read only but before we set it to read only,
6509          * some task might have had allocated an extent from it already, but it
6510          * has not yet created a respective ordered extent (and added it to a
6511          * root's list of ordered extents).
6512          * Therefore wait for any task currently allocating extents, since the
6513          * block group's reservations counter is incremented while a read lock
6514          * on the groups' semaphore is held and decremented after releasing
6515          * the read access on that semaphore and creating the ordered extent.
6516          */
6517         down_write(&space_info->groups_sem);
6518         up_write(&space_info->groups_sem);
6519
6520         wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
6521 }
6522
6523 /**
6524  * btrfs_add_reserved_bytes - update the block_group and space info counters
6525  * @cache:      The cache we are manipulating
6526  * @ram_bytes:  The number of bytes of file content, and will be same to
6527  *              @num_bytes except for the compress path.
6528  * @num_bytes:  The number of bytes in question
6529  * @delalloc:   The blocks are allocated for the delalloc write
6530  *
6531  * This is called by the allocator when it reserves space. If this is a
6532  * reservation and the block group has become read only we cannot make the
6533  * reservation and return -EAGAIN, otherwise this function always succeeds.
6534  */
6535 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6536                                     u64 ram_bytes, u64 num_bytes, int delalloc)
6537 {
6538         struct btrfs_space_info *space_info = cache->space_info;
6539         int ret = 0;
6540
6541         spin_lock(&space_info->lock);
6542         spin_lock(&cache->lock);
6543         if (cache->ro) {
6544                 ret = -EAGAIN;
6545         } else {
6546                 cache->reserved += num_bytes;
6547                 space_info->bytes_reserved += num_bytes;
6548
6549                 trace_btrfs_space_reservation(cache->fs_info,
6550                                 "space_info", space_info->flags,
6551                                 ram_bytes, 0);
6552                 space_info->bytes_may_use -= ram_bytes;
6553                 if (delalloc)
6554                         cache->delalloc_bytes += num_bytes;
6555         }
6556         spin_unlock(&cache->lock);
6557         spin_unlock(&space_info->lock);
6558         return ret;
6559 }
6560
6561 /**
6562  * btrfs_free_reserved_bytes - update the block_group and space info counters
6563  * @cache:      The cache we are manipulating
6564  * @num_bytes:  The number of bytes in question
6565  * @delalloc:   The blocks are allocated for the delalloc write
6566  *
6567  * This is called by somebody who is freeing space that was never actually used
6568  * on disk.  For example if you reserve some space for a new leaf in transaction
6569  * A and before transaction A commits you free that leaf, you call this with
6570  * reserve set to 0 in order to clear the reservation.
6571  */
6572
6573 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6574                                      u64 num_bytes, int delalloc)
6575 {
6576         struct btrfs_space_info *space_info = cache->space_info;
6577         int ret = 0;
6578
6579         spin_lock(&space_info->lock);
6580         spin_lock(&cache->lock);
6581         if (cache->ro)
6582                 space_info->bytes_readonly += num_bytes;
6583         cache->reserved -= num_bytes;
6584         space_info->bytes_reserved -= num_bytes;
6585
6586         if (delalloc)
6587                 cache->delalloc_bytes -= num_bytes;
6588         spin_unlock(&cache->lock);
6589         spin_unlock(&space_info->lock);
6590         return ret;
6591 }
6592 void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
6593 {
6594         struct btrfs_caching_control *next;
6595         struct btrfs_caching_control *caching_ctl;
6596         struct btrfs_block_group_cache *cache;
6597
6598         down_write(&fs_info->commit_root_sem);
6599
6600         list_for_each_entry_safe(caching_ctl, next,
6601                                  &fs_info->caching_block_groups, list) {
6602                 cache = caching_ctl->block_group;
6603                 if (block_group_cache_done(cache)) {
6604                         cache->last_byte_to_unpin = (u64)-1;
6605                         list_del_init(&caching_ctl->list);
6606                         put_caching_control(caching_ctl);
6607                 } else {
6608                         cache->last_byte_to_unpin = caching_ctl->progress;
6609                 }
6610         }
6611
6612         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6613                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6614         else
6615                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6616
6617         up_write(&fs_info->commit_root_sem);
6618
6619         update_global_block_rsv(fs_info);
6620 }
6621
6622 /*
6623  * Returns the free cluster for the given space info and sets empty_cluster to
6624  * what it should be based on the mount options.
6625  */
6626 static struct btrfs_free_cluster *
6627 fetch_cluster_info(struct btrfs_fs_info *fs_info,
6628                    struct btrfs_space_info *space_info, u64 *empty_cluster)
6629 {
6630         struct btrfs_free_cluster *ret = NULL;
6631
6632         *empty_cluster = 0;
6633         if (btrfs_mixed_space_info(space_info))
6634                 return ret;
6635
6636         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6637                 ret = &fs_info->meta_alloc_cluster;
6638                 if (btrfs_test_opt(fs_info, SSD))
6639                         *empty_cluster = SZ_2M;
6640                 else
6641                         *empty_cluster = SZ_64K;
6642         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
6643                    btrfs_test_opt(fs_info, SSD_SPREAD)) {
6644                 *empty_cluster = SZ_2M;
6645                 ret = &fs_info->data_alloc_cluster;
6646         }
6647
6648         return ret;
6649 }
6650
6651 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
6652                               u64 start, u64 end,
6653                               const bool return_free_space)
6654 {
6655         struct btrfs_block_group_cache *cache = NULL;
6656         struct btrfs_space_info *space_info;
6657         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6658         struct btrfs_free_cluster *cluster = NULL;
6659         u64 len;
6660         u64 total_unpinned = 0;
6661         u64 empty_cluster = 0;
6662         bool readonly;
6663
6664         while (start <= end) {
6665                 readonly = false;
6666                 if (!cache ||
6667                     start >= cache->key.objectid + cache->key.offset) {
6668                         if (cache)
6669                                 btrfs_put_block_group(cache);
6670                         total_unpinned = 0;
6671                         cache = btrfs_lookup_block_group(fs_info, start);
6672                         BUG_ON(!cache); /* Logic error */
6673
6674                         cluster = fetch_cluster_info(fs_info,
6675                                                      cache->space_info,
6676                                                      &empty_cluster);
6677                         empty_cluster <<= 1;
6678                 }
6679
6680                 len = cache->key.objectid + cache->key.offset - start;
6681                 len = min(len, end + 1 - start);
6682
6683                 if (start < cache->last_byte_to_unpin) {
6684                         len = min(len, cache->last_byte_to_unpin - start);
6685                         if (return_free_space)
6686                                 btrfs_add_free_space(cache, start, len);
6687                 }
6688
6689                 start += len;
6690                 total_unpinned += len;
6691                 space_info = cache->space_info;
6692
6693                 /*
6694                  * If this space cluster has been marked as fragmented and we've
6695                  * unpinned enough in this block group to potentially allow a
6696                  * cluster to be created inside of it go ahead and clear the
6697                  * fragmented check.
6698                  */
6699                 if (cluster && cluster->fragmented &&
6700                     total_unpinned > empty_cluster) {
6701                         spin_lock(&cluster->lock);
6702                         cluster->fragmented = 0;
6703                         spin_unlock(&cluster->lock);
6704                 }
6705
6706                 spin_lock(&space_info->lock);
6707                 spin_lock(&cache->lock);
6708                 cache->pinned -= len;
6709                 space_info->bytes_pinned -= len;
6710
6711                 trace_btrfs_space_reservation(fs_info, "pinned",
6712                                               space_info->flags, len, 0);
6713                 space_info->max_extent_size = 0;
6714                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6715                 if (cache->ro) {
6716                         space_info->bytes_readonly += len;
6717                         readonly = true;
6718                 }
6719                 spin_unlock(&cache->lock);
6720                 if (!readonly && return_free_space &&
6721                     global_rsv->space_info == space_info) {
6722                         u64 to_add = len;
6723
6724                         spin_lock(&global_rsv->lock);
6725                         if (!global_rsv->full) {
6726                                 to_add = min(len, global_rsv->size -
6727                                              global_rsv->reserved);
6728                                 global_rsv->reserved += to_add;
6729                                 space_info->bytes_may_use += to_add;
6730                                 if (global_rsv->reserved >= global_rsv->size)
6731                                         global_rsv->full = 1;
6732                                 trace_btrfs_space_reservation(fs_info,
6733                                                               "space_info",
6734                                                               space_info->flags,
6735                                                               to_add, 1);
6736                                 len -= to_add;
6737                         }
6738                         spin_unlock(&global_rsv->lock);
6739                         /* Add to any tickets we may have */
6740                         if (len)
6741                                 space_info_add_new_bytes(fs_info, space_info,
6742                                                          len);
6743                 }
6744                 spin_unlock(&space_info->lock);
6745         }
6746
6747         if (cache)
6748                 btrfs_put_block_group(cache);
6749         return 0;
6750 }
6751
6752 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
6753 {
6754         struct btrfs_fs_info *fs_info = trans->fs_info;
6755         struct btrfs_block_group_cache *block_group, *tmp;
6756         struct list_head *deleted_bgs;
6757         struct extent_io_tree *unpin;
6758         u64 start;
6759         u64 end;
6760         int ret;
6761
6762         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6763                 unpin = &fs_info->freed_extents[1];
6764         else
6765                 unpin = &fs_info->freed_extents[0];
6766
6767         while (!trans->aborted) {
6768                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6769                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6770                                             EXTENT_DIRTY, NULL);
6771                 if (ret) {
6772                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6773                         break;
6774                 }
6775
6776                 if (btrfs_test_opt(fs_info, DISCARD))
6777                         ret = btrfs_discard_extent(fs_info, start,
6778                                                    end + 1 - start, NULL);
6779
6780                 clear_extent_dirty(unpin, start, end);
6781                 unpin_extent_range(fs_info, start, end, true);
6782                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6783                 cond_resched();
6784         }
6785
6786         /*
6787          * Transaction is finished.  We don't need the lock anymore.  We
6788          * do need to clean up the block groups in case of a transaction
6789          * abort.
6790          */
6791         deleted_bgs = &trans->transaction->deleted_bgs;
6792         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6793                 u64 trimmed = 0;
6794
6795                 ret = -EROFS;
6796                 if (!trans->aborted)
6797                         ret = btrfs_discard_extent(fs_info,
6798                                                    block_group->key.objectid,
6799                                                    block_group->key.offset,
6800                                                    &trimmed);
6801
6802                 list_del_init(&block_group->bg_list);
6803                 btrfs_put_block_group_trimming(block_group);
6804                 btrfs_put_block_group(block_group);
6805
6806                 if (ret) {
6807                         const char *errstr = btrfs_decode_error(ret);
6808                         btrfs_warn(fs_info,
6809                            "discard failed while removing blockgroup: errno=%d %s",
6810                                    ret, errstr);
6811                 }
6812         }
6813
6814         return 0;
6815 }
6816
6817 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6818                                 struct btrfs_fs_info *info,
6819                                 struct btrfs_delayed_ref_node *node, u64 parent,
6820                                 u64 root_objectid, u64 owner_objectid,
6821                                 u64 owner_offset, int refs_to_drop,
6822                                 struct btrfs_delayed_extent_op *extent_op)
6823 {
6824         struct btrfs_key key;
6825         struct btrfs_path *path;
6826         struct btrfs_root *extent_root = info->extent_root;
6827         struct extent_buffer *leaf;
6828         struct btrfs_extent_item *ei;
6829         struct btrfs_extent_inline_ref *iref;
6830         int ret;
6831         int is_data;
6832         int extent_slot = 0;
6833         int found_extent = 0;
6834         int num_to_del = 1;
6835         u32 item_size;
6836         u64 refs;
6837         u64 bytenr = node->bytenr;
6838         u64 num_bytes = node->num_bytes;
6839         int last_ref = 0;
6840         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
6841
6842         path = btrfs_alloc_path();
6843         if (!path)
6844                 return -ENOMEM;
6845
6846         path->reada = READA_FORWARD;
6847         path->leave_spinning = 1;
6848
6849         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6850         BUG_ON(!is_data && refs_to_drop != 1);
6851
6852         if (is_data)
6853                 skinny_metadata = false;
6854
6855         ret = lookup_extent_backref(trans, info, path, &iref,
6856                                     bytenr, num_bytes, parent,
6857                                     root_objectid, owner_objectid,
6858                                     owner_offset);
6859         if (ret == 0) {
6860                 extent_slot = path->slots[0];
6861                 while (extent_slot >= 0) {
6862                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6863                                               extent_slot);
6864                         if (key.objectid != bytenr)
6865                                 break;
6866                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6867                             key.offset == num_bytes) {
6868                                 found_extent = 1;
6869                                 break;
6870                         }
6871                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6872                             key.offset == owner_objectid) {
6873                                 found_extent = 1;
6874                                 break;
6875                         }
6876                         if (path->slots[0] - extent_slot > 5)
6877                                 break;
6878                         extent_slot--;
6879                 }
6880 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6881                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6882                 if (found_extent && item_size < sizeof(*ei))
6883                         found_extent = 0;
6884 #endif
6885                 if (!found_extent) {
6886                         BUG_ON(iref);
6887                         ret = remove_extent_backref(trans, info, path, NULL,
6888                                                     refs_to_drop,
6889                                                     is_data, &last_ref);
6890                         if (ret) {
6891                                 btrfs_abort_transaction(trans, ret);
6892                                 goto out;
6893                         }
6894                         btrfs_release_path(path);
6895                         path->leave_spinning = 1;
6896
6897                         key.objectid = bytenr;
6898                         key.type = BTRFS_EXTENT_ITEM_KEY;
6899                         key.offset = num_bytes;
6900
6901                         if (!is_data && skinny_metadata) {
6902                                 key.type = BTRFS_METADATA_ITEM_KEY;
6903                                 key.offset = owner_objectid;
6904                         }
6905
6906                         ret = btrfs_search_slot(trans, extent_root,
6907                                                 &key, path, -1, 1);
6908                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6909                                 /*
6910                                  * Couldn't find our skinny metadata item,
6911                                  * see if we have ye olde extent item.
6912                                  */
6913                                 path->slots[0]--;
6914                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6915                                                       path->slots[0]);
6916                                 if (key.objectid == bytenr &&
6917                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6918                                     key.offset == num_bytes)
6919                                         ret = 0;
6920                         }
6921
6922                         if (ret > 0 && skinny_metadata) {
6923                                 skinny_metadata = false;
6924                                 key.objectid = bytenr;
6925                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6926                                 key.offset = num_bytes;
6927                                 btrfs_release_path(path);
6928                                 ret = btrfs_search_slot(trans, extent_root,
6929                                                         &key, path, -1, 1);
6930                         }
6931
6932                         if (ret) {
6933                                 btrfs_err(info,
6934                                           "umm, got %d back from search, was looking for %llu",
6935                                           ret, bytenr);
6936                                 if (ret > 0)
6937                                         btrfs_print_leaf(path->nodes[0]);
6938                         }
6939                         if (ret < 0) {
6940                                 btrfs_abort_transaction(trans, ret);
6941                                 goto out;
6942                         }
6943                         extent_slot = path->slots[0];
6944                 }
6945         } else if (WARN_ON(ret == -ENOENT)) {
6946                 btrfs_print_leaf(path->nodes[0]);
6947                 btrfs_err(info,
6948                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6949                         bytenr, parent, root_objectid, owner_objectid,
6950                         owner_offset);
6951                 btrfs_abort_transaction(trans, ret);
6952                 goto out;
6953         } else {
6954                 btrfs_abort_transaction(trans, ret);
6955                 goto out;
6956         }
6957
6958         leaf = path->nodes[0];
6959         item_size = btrfs_item_size_nr(leaf, extent_slot);
6960 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6961         if (item_size < sizeof(*ei)) {
6962                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6963                 ret = convert_extent_item_v0(trans, info, path, owner_objectid,
6964                                              0);
6965                 if (ret < 0) {
6966                         btrfs_abort_transaction(trans, ret);
6967                         goto out;
6968                 }
6969
6970                 btrfs_release_path(path);
6971                 path->leave_spinning = 1;
6972
6973                 key.objectid = bytenr;
6974                 key.type = BTRFS_EXTENT_ITEM_KEY;
6975                 key.offset = num_bytes;
6976
6977                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6978                                         -1, 1);
6979                 if (ret) {
6980                         btrfs_err(info,
6981                                   "umm, got %d back from search, was looking for %llu",
6982                                 ret, bytenr);
6983                         btrfs_print_leaf(path->nodes[0]);
6984                 }
6985                 if (ret < 0) {
6986                         btrfs_abort_transaction(trans, ret);
6987                         goto out;
6988                 }
6989
6990                 extent_slot = path->slots[0];
6991                 leaf = path->nodes[0];
6992                 item_size = btrfs_item_size_nr(leaf, extent_slot);
6993         }
6994 #endif
6995         BUG_ON(item_size < sizeof(*ei));
6996         ei = btrfs_item_ptr(leaf, extent_slot,
6997                             struct btrfs_extent_item);
6998         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6999             key.type == BTRFS_EXTENT_ITEM_KEY) {
7000                 struct btrfs_tree_block_info *bi;
7001                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
7002                 bi = (struct btrfs_tree_block_info *)(ei + 1);
7003                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
7004         }
7005
7006         refs = btrfs_extent_refs(leaf, ei);
7007         if (refs < refs_to_drop) {
7008                 btrfs_err(info,
7009                           "trying to drop %d refs but we only have %Lu for bytenr %Lu",
7010                           refs_to_drop, refs, bytenr);
7011                 ret = -EINVAL;
7012                 btrfs_abort_transaction(trans, ret);
7013                 goto out;
7014         }
7015         refs -= refs_to_drop;
7016
7017         if (refs > 0) {
7018                 if (extent_op)
7019                         __run_delayed_extent_op(extent_op, leaf, ei);
7020                 /*
7021                  * In the case of inline back ref, reference count will
7022                  * be updated by remove_extent_backref
7023                  */
7024                 if (iref) {
7025                         BUG_ON(!found_extent);
7026                 } else {
7027                         btrfs_set_extent_refs(leaf, ei, refs);
7028                         btrfs_mark_buffer_dirty(leaf);
7029                 }
7030                 if (found_extent) {
7031                         ret = remove_extent_backref(trans, info, path,
7032                                                     iref, refs_to_drop,
7033                                                     is_data, &last_ref);
7034                         if (ret) {
7035                                 btrfs_abort_transaction(trans, ret);
7036                                 goto out;
7037                         }
7038                 }
7039         } else {
7040                 if (found_extent) {
7041                         BUG_ON(is_data && refs_to_drop !=
7042                                extent_data_ref_count(path, iref));
7043                         if (iref) {
7044                                 BUG_ON(path->slots[0] != extent_slot);
7045                         } else {
7046                                 BUG_ON(path->slots[0] != extent_slot + 1);
7047                                 path->slots[0] = extent_slot;
7048                                 num_to_del = 2;
7049                         }
7050                 }
7051
7052                 last_ref = 1;
7053                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
7054                                       num_to_del);
7055                 if (ret) {
7056                         btrfs_abort_transaction(trans, ret);
7057                         goto out;
7058                 }
7059                 btrfs_release_path(path);
7060
7061                 if (is_data) {
7062                         ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
7063                         if (ret) {
7064                                 btrfs_abort_transaction(trans, ret);
7065                                 goto out;
7066                         }
7067                 }
7068
7069                 ret = add_to_free_space_tree(trans, bytenr, num_bytes);
7070                 if (ret) {
7071                         btrfs_abort_transaction(trans, ret);
7072                         goto out;
7073                 }
7074
7075                 ret = update_block_group(trans, info, bytenr, num_bytes, 0);
7076                 if (ret) {
7077                         btrfs_abort_transaction(trans, ret);
7078                         goto out;
7079                 }
7080         }
7081         btrfs_release_path(path);
7082
7083 out:
7084         btrfs_free_path(path);
7085         return ret;
7086 }
7087
7088 /*
7089  * when we free an block, it is possible (and likely) that we free the last
7090  * delayed ref for that extent as well.  This searches the delayed ref tree for
7091  * a given extent, and if there are no other delayed refs to be processed, it
7092  * removes it from the tree.
7093  */
7094 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
7095                                       u64 bytenr)
7096 {
7097         struct btrfs_delayed_ref_head *head;
7098         struct btrfs_delayed_ref_root *delayed_refs;
7099         int ret = 0;
7100
7101         delayed_refs = &trans->transaction->delayed_refs;
7102         spin_lock(&delayed_refs->lock);
7103         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
7104         if (!head)
7105                 goto out_delayed_unlock;
7106
7107         spin_lock(&head->lock);
7108         if (!RB_EMPTY_ROOT(&head->ref_tree))
7109                 goto out;
7110
7111         if (head->extent_op) {
7112                 if (!head->must_insert_reserved)
7113                         goto out;
7114                 btrfs_free_delayed_extent_op(head->extent_op);
7115                 head->extent_op = NULL;
7116         }
7117
7118         /*
7119          * waiting for the lock here would deadlock.  If someone else has it
7120          * locked they are already in the process of dropping it anyway
7121          */
7122         if (!mutex_trylock(&head->mutex))
7123                 goto out;
7124
7125         /*
7126          * at this point we have a head with no other entries.  Go
7127          * ahead and process it.
7128          */
7129         rb_erase(&head->href_node, &delayed_refs->href_root);
7130         RB_CLEAR_NODE(&head->href_node);
7131         atomic_dec(&delayed_refs->num_entries);
7132
7133         /*
7134          * we don't take a ref on the node because we're removing it from the
7135          * tree, so we just steal the ref the tree was holding.
7136          */
7137         delayed_refs->num_heads--;
7138         if (head->processing == 0)
7139                 delayed_refs->num_heads_ready--;
7140         head->processing = 0;
7141         spin_unlock(&head->lock);
7142         spin_unlock(&delayed_refs->lock);
7143
7144         BUG_ON(head->extent_op);
7145         if (head->must_insert_reserved)
7146                 ret = 1;
7147
7148         mutex_unlock(&head->mutex);
7149         btrfs_put_delayed_ref_head(head);
7150         return ret;
7151 out:
7152         spin_unlock(&head->lock);
7153
7154 out_delayed_unlock:
7155         spin_unlock(&delayed_refs->lock);
7156         return 0;
7157 }
7158
7159 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7160                            struct btrfs_root *root,
7161                            struct extent_buffer *buf,
7162                            u64 parent, int last_ref)
7163 {
7164         struct btrfs_fs_info *fs_info = root->fs_info;
7165         int pin = 1;
7166         int ret;
7167
7168         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7169                 int old_ref_mod, new_ref_mod;
7170
7171                 btrfs_ref_tree_mod(root, buf->start, buf->len, parent,
7172                                    root->root_key.objectid,
7173                                    btrfs_header_level(buf), 0,
7174                                    BTRFS_DROP_DELAYED_REF);
7175                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, buf->start,
7176                                                  buf->len, parent,
7177                                                  root->root_key.objectid,
7178                                                  btrfs_header_level(buf),
7179                                                  BTRFS_DROP_DELAYED_REF, NULL,
7180                                                  &old_ref_mod, &new_ref_mod);
7181                 BUG_ON(ret); /* -ENOMEM */
7182                 pin = old_ref_mod >= 0 && new_ref_mod < 0;
7183         }
7184
7185         if (last_ref && btrfs_header_generation(buf) == trans->transid) {
7186                 struct btrfs_block_group_cache *cache;
7187
7188                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7189                         ret = check_ref_cleanup(trans, buf->start);
7190                         if (!ret)
7191                                 goto out;
7192                 }
7193
7194                 pin = 0;
7195                 cache = btrfs_lookup_block_group(fs_info, buf->start);
7196
7197                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7198                         pin_down_extent(fs_info, cache, buf->start,
7199                                         buf->len, 1);
7200                         btrfs_put_block_group(cache);
7201                         goto out;
7202                 }
7203
7204                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7205
7206                 btrfs_add_free_space(cache, buf->start, buf->len);
7207                 btrfs_free_reserved_bytes(cache, buf->len, 0);
7208                 btrfs_put_block_group(cache);
7209                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
7210         }
7211 out:
7212         if (pin)
7213                 add_pinned_bytes(fs_info, buf->len, true,
7214                                  root->root_key.objectid);
7215
7216         if (last_ref) {
7217                 /*
7218                  * Deleting the buffer, clear the corrupt flag since it doesn't
7219                  * matter anymore.
7220                  */
7221                 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7222         }
7223 }
7224
7225 /* Can return -ENOMEM */
7226 int btrfs_free_extent(struct btrfs_trans_handle *trans,
7227                       struct btrfs_root *root,
7228                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7229                       u64 owner, u64 offset)
7230 {
7231         struct btrfs_fs_info *fs_info = root->fs_info;
7232         int old_ref_mod, new_ref_mod;
7233         int ret;
7234
7235         if (btrfs_is_testing(fs_info))
7236                 return 0;
7237
7238         if (root_objectid != BTRFS_TREE_LOG_OBJECTID)
7239                 btrfs_ref_tree_mod(root, bytenr, num_bytes, parent,
7240                                    root_objectid, owner, offset,
7241                                    BTRFS_DROP_DELAYED_REF);
7242
7243         /*
7244          * tree log blocks never actually go into the extent allocation
7245          * tree, just update pinning info and exit early.
7246          */
7247         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7248                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7249                 /* unlocks the pinned mutex */
7250                 btrfs_pin_extent(fs_info, bytenr, num_bytes, 1);
7251                 old_ref_mod = new_ref_mod = 0;
7252                 ret = 0;
7253         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7254                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7255                                                  num_bytes, parent,
7256                                                  root_objectid, (int)owner,
7257                                                  BTRFS_DROP_DELAYED_REF, NULL,
7258                                                  &old_ref_mod, &new_ref_mod);
7259         } else {
7260                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7261                                                  num_bytes, parent,
7262                                                  root_objectid, owner, offset,
7263                                                  0, BTRFS_DROP_DELAYED_REF,
7264                                                  &old_ref_mod, &new_ref_mod);
7265         }
7266
7267         if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0) {
7268                 bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
7269
7270                 add_pinned_bytes(fs_info, num_bytes, metadata, root_objectid);
7271         }
7272
7273         return ret;
7274 }
7275
7276 /*
7277  * when we wait for progress in the block group caching, its because
7278  * our allocation attempt failed at least once.  So, we must sleep
7279  * and let some progress happen before we try again.
7280  *
7281  * This function will sleep at least once waiting for new free space to
7282  * show up, and then it will check the block group free space numbers
7283  * for our min num_bytes.  Another option is to have it go ahead
7284  * and look in the rbtree for a free extent of a given size, but this
7285  * is a good start.
7286  *
7287  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7288  * any of the information in this block group.
7289  */
7290 static noinline void
7291 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7292                                 u64 num_bytes)
7293 {
7294         struct btrfs_caching_control *caching_ctl;
7295
7296         caching_ctl = get_caching_control(cache);
7297         if (!caching_ctl)
7298                 return;
7299
7300         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7301                    (cache->free_space_ctl->free_space >= num_bytes));
7302
7303         put_caching_control(caching_ctl);
7304 }
7305
7306 static noinline int
7307 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7308 {
7309         struct btrfs_caching_control *caching_ctl;
7310         int ret = 0;
7311
7312         caching_ctl = get_caching_control(cache);
7313         if (!caching_ctl)
7314                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7315
7316         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7317         if (cache->cached == BTRFS_CACHE_ERROR)
7318                 ret = -EIO;
7319         put_caching_control(caching_ctl);
7320         return ret;
7321 }
7322
7323 enum btrfs_loop_type {
7324         LOOP_CACHING_NOWAIT = 0,
7325         LOOP_CACHING_WAIT = 1,
7326         LOOP_ALLOC_CHUNK = 2,
7327         LOOP_NO_EMPTY_SIZE = 3,
7328 };
7329
7330 static inline void
7331 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7332                        int delalloc)
7333 {
7334         if (delalloc)
7335                 down_read(&cache->data_rwsem);
7336 }
7337
7338 static inline void
7339 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7340                        int delalloc)
7341 {
7342         btrfs_get_block_group(cache);
7343         if (delalloc)
7344                 down_read(&cache->data_rwsem);
7345 }
7346
7347 static struct btrfs_block_group_cache *
7348 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7349                    struct btrfs_free_cluster *cluster,
7350                    int delalloc)
7351 {
7352         struct btrfs_block_group_cache *used_bg = NULL;
7353
7354         spin_lock(&cluster->refill_lock);
7355         while (1) {
7356                 used_bg = cluster->block_group;
7357                 if (!used_bg)
7358                         return NULL;
7359
7360                 if (used_bg == block_group)
7361                         return used_bg;
7362
7363                 btrfs_get_block_group(used_bg);
7364
7365                 if (!delalloc)
7366                         return used_bg;
7367
7368                 if (down_read_trylock(&used_bg->data_rwsem))
7369                         return used_bg;
7370
7371                 spin_unlock(&cluster->refill_lock);
7372
7373                 /* We should only have one-level nested. */
7374                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
7375
7376                 spin_lock(&cluster->refill_lock);
7377                 if (used_bg == cluster->block_group)
7378                         return used_bg;
7379
7380                 up_read(&used_bg->data_rwsem);
7381                 btrfs_put_block_group(used_bg);
7382         }
7383 }
7384
7385 static inline void
7386 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7387                          int delalloc)
7388 {
7389         if (delalloc)
7390                 up_read(&cache->data_rwsem);
7391         btrfs_put_block_group(cache);
7392 }
7393
7394 /*
7395  * walks the btree of allocated extents and find a hole of a given size.
7396  * The key ins is changed to record the hole:
7397  * ins->objectid == start position
7398  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7399  * ins->offset == the size of the hole.
7400  * Any available blocks before search_start are skipped.
7401  *
7402  * If there is no suitable free space, we will record the max size of
7403  * the free space extent currently.
7404  */
7405 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
7406                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7407                                 u64 hint_byte, struct btrfs_key *ins,
7408                                 u64 flags, int delalloc)
7409 {
7410         int ret = 0;
7411         struct btrfs_root *root = fs_info->extent_root;
7412         struct btrfs_free_cluster *last_ptr = NULL;
7413         struct btrfs_block_group_cache *block_group = NULL;
7414         u64 search_start = 0;
7415         u64 max_extent_size = 0;
7416         u64 empty_cluster = 0;
7417         struct btrfs_space_info *space_info;
7418         int loop = 0;
7419         int index = btrfs_bg_flags_to_raid_index(flags);
7420         bool failed_cluster_refill = false;
7421         bool failed_alloc = false;
7422         bool use_cluster = true;
7423         bool have_caching_bg = false;
7424         bool orig_have_caching_bg = false;
7425         bool full_search = false;
7426
7427         WARN_ON(num_bytes < fs_info->sectorsize);
7428         ins->type = BTRFS_EXTENT_ITEM_KEY;
7429         ins->objectid = 0;
7430         ins->offset = 0;
7431
7432         trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
7433
7434         space_info = __find_space_info(fs_info, flags);
7435         if (!space_info) {
7436                 btrfs_err(fs_info, "No space info for %llu", flags);
7437                 return -ENOSPC;
7438         }
7439
7440         /*
7441          * If our free space is heavily fragmented we may not be able to make
7442          * big contiguous allocations, so instead of doing the expensive search
7443          * for free space, simply return ENOSPC with our max_extent_size so we
7444          * can go ahead and search for a more manageable chunk.
7445          *
7446          * If our max_extent_size is large enough for our allocation simply
7447          * disable clustering since we will likely not be able to find enough
7448          * space to create a cluster and induce latency trying.
7449          */
7450         if (unlikely(space_info->max_extent_size)) {
7451                 spin_lock(&space_info->lock);
7452                 if (space_info->max_extent_size &&
7453                     num_bytes > space_info->max_extent_size) {
7454                         ins->offset = space_info->max_extent_size;
7455                         spin_unlock(&space_info->lock);
7456                         return -ENOSPC;
7457                 } else if (space_info->max_extent_size) {
7458                         use_cluster = false;
7459                 }
7460                 spin_unlock(&space_info->lock);
7461         }
7462
7463         last_ptr = fetch_cluster_info(fs_info, space_info, &empty_cluster);
7464         if (last_ptr) {
7465                 spin_lock(&last_ptr->lock);
7466                 if (last_ptr->block_group)
7467                         hint_byte = last_ptr->window_start;
7468                 if (last_ptr->fragmented) {
7469                         /*
7470                          * We still set window_start so we can keep track of the
7471                          * last place we found an allocation to try and save
7472                          * some time.
7473                          */
7474                         hint_byte = last_ptr->window_start;
7475                         use_cluster = false;
7476                 }
7477                 spin_unlock(&last_ptr->lock);
7478         }
7479
7480         search_start = max(search_start, first_logical_byte(fs_info, 0));
7481         search_start = max(search_start, hint_byte);
7482         if (search_start == hint_byte) {
7483                 block_group = btrfs_lookup_block_group(fs_info, search_start);
7484                 /*
7485                  * we don't want to use the block group if it doesn't match our
7486                  * allocation bits, or if its not cached.
7487                  *
7488                  * However if we are re-searching with an ideal block group
7489                  * picked out then we don't care that the block group is cached.
7490                  */
7491                 if (block_group && block_group_bits(block_group, flags) &&
7492                     block_group->cached != BTRFS_CACHE_NO) {
7493                         down_read(&space_info->groups_sem);
7494                         if (list_empty(&block_group->list) ||
7495                             block_group->ro) {
7496                                 /*
7497                                  * someone is removing this block group,
7498                                  * we can't jump into the have_block_group
7499                                  * target because our list pointers are not
7500                                  * valid
7501                                  */
7502                                 btrfs_put_block_group(block_group);
7503                                 up_read(&space_info->groups_sem);
7504                         } else {
7505                                 index = btrfs_bg_flags_to_raid_index(
7506                                                 block_group->flags);
7507                                 btrfs_lock_block_group(block_group, delalloc);
7508                                 goto have_block_group;
7509                         }
7510                 } else if (block_group) {
7511                         btrfs_put_block_group(block_group);
7512                 }
7513         }
7514 search:
7515         have_caching_bg = false;
7516         if (index == 0 || index == btrfs_bg_flags_to_raid_index(flags))
7517                 full_search = true;
7518         down_read(&space_info->groups_sem);
7519         list_for_each_entry(block_group, &space_info->block_groups[index],
7520                             list) {
7521                 u64 offset;
7522                 int cached;
7523
7524                 /* If the block group is read-only, we can skip it entirely. */
7525                 if (unlikely(block_group->ro))
7526                         continue;
7527
7528                 btrfs_grab_block_group(block_group, delalloc);
7529                 search_start = block_group->key.objectid;
7530
7531                 /*
7532                  * this can happen if we end up cycling through all the
7533                  * raid types, but we want to make sure we only allocate
7534                  * for the proper type.
7535                  */
7536                 if (!block_group_bits(block_group, flags)) {
7537                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
7538                                 BTRFS_BLOCK_GROUP_RAID1 |
7539                                 BTRFS_BLOCK_GROUP_RAID5 |
7540                                 BTRFS_BLOCK_GROUP_RAID6 |
7541                                 BTRFS_BLOCK_GROUP_RAID10;
7542
7543                         /*
7544                          * if they asked for extra copies and this block group
7545                          * doesn't provide them, bail.  This does allow us to
7546                          * fill raid0 from raid1.
7547                          */
7548                         if ((flags & extra) && !(block_group->flags & extra))
7549                                 goto loop;
7550                 }
7551
7552 have_block_group:
7553                 cached = block_group_cache_done(block_group);
7554                 if (unlikely(!cached)) {
7555                         have_caching_bg = true;
7556                         ret = cache_block_group(block_group, 0);
7557                         BUG_ON(ret < 0);
7558                         ret = 0;
7559                 }
7560
7561                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7562                         goto loop;
7563
7564                 /*
7565                  * Ok we want to try and use the cluster allocator, so
7566                  * lets look there
7567                  */
7568                 if (last_ptr && use_cluster) {
7569                         struct btrfs_block_group_cache *used_block_group;
7570                         unsigned long aligned_cluster;
7571                         /*
7572                          * the refill lock keeps out other
7573                          * people trying to start a new cluster
7574                          */
7575                         used_block_group = btrfs_lock_cluster(block_group,
7576                                                               last_ptr,
7577                                                               delalloc);
7578                         if (!used_block_group)
7579                                 goto refill_cluster;
7580
7581                         if (used_block_group != block_group &&
7582                             (used_block_group->ro ||
7583                              !block_group_bits(used_block_group, flags)))
7584                                 goto release_cluster;
7585
7586                         offset = btrfs_alloc_from_cluster(used_block_group,
7587                                                 last_ptr,
7588                                                 num_bytes,
7589                                                 used_block_group->key.objectid,
7590                                                 &max_extent_size);
7591                         if (offset) {
7592                                 /* we have a block, we're done */
7593                                 spin_unlock(&last_ptr->refill_lock);
7594                                 trace_btrfs_reserve_extent_cluster(
7595                                                 used_block_group,
7596                                                 search_start, num_bytes);
7597                                 if (used_block_group != block_group) {
7598                                         btrfs_release_block_group(block_group,
7599                                                                   delalloc);
7600                                         block_group = used_block_group;
7601                                 }
7602                                 goto checks;
7603                         }
7604
7605                         WARN_ON(last_ptr->block_group != used_block_group);
7606 release_cluster:
7607                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7608                          * set up a new clusters, so lets just skip it
7609                          * and let the allocator find whatever block
7610                          * it can find.  If we reach this point, we
7611                          * will have tried the cluster allocator
7612                          * plenty of times and not have found
7613                          * anything, so we are likely way too
7614                          * fragmented for the clustering stuff to find
7615                          * anything.
7616                          *
7617                          * However, if the cluster is taken from the
7618                          * current block group, release the cluster
7619                          * first, so that we stand a better chance of
7620                          * succeeding in the unclustered
7621                          * allocation.  */
7622                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7623                             used_block_group != block_group) {
7624                                 spin_unlock(&last_ptr->refill_lock);
7625                                 btrfs_release_block_group(used_block_group,
7626                                                           delalloc);
7627                                 goto unclustered_alloc;
7628                         }
7629
7630                         /*
7631                          * this cluster didn't work out, free it and
7632                          * start over
7633                          */
7634                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7635
7636                         if (used_block_group != block_group)
7637                                 btrfs_release_block_group(used_block_group,
7638                                                           delalloc);
7639 refill_cluster:
7640                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7641                                 spin_unlock(&last_ptr->refill_lock);
7642                                 goto unclustered_alloc;
7643                         }
7644
7645                         aligned_cluster = max_t(unsigned long,
7646                                                 empty_cluster + empty_size,
7647                                               block_group->full_stripe_len);
7648
7649                         /* allocate a cluster in this block group */
7650                         ret = btrfs_find_space_cluster(fs_info, block_group,
7651                                                        last_ptr, search_start,
7652                                                        num_bytes,
7653                                                        aligned_cluster);
7654                         if (ret == 0) {
7655                                 /*
7656                                  * now pull our allocation out of this
7657                                  * cluster
7658                                  */
7659                                 offset = btrfs_alloc_from_cluster(block_group,
7660                                                         last_ptr,
7661                                                         num_bytes,
7662                                                         search_start,
7663                                                         &max_extent_size);
7664                                 if (offset) {
7665                                         /* we found one, proceed */
7666                                         spin_unlock(&last_ptr->refill_lock);
7667                                         trace_btrfs_reserve_extent_cluster(
7668                                                 block_group, search_start,
7669                                                 num_bytes);
7670                                         goto checks;
7671                                 }
7672                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7673                                    && !failed_cluster_refill) {
7674                                 spin_unlock(&last_ptr->refill_lock);
7675
7676                                 failed_cluster_refill = true;
7677                                 wait_block_group_cache_progress(block_group,
7678                                        num_bytes + empty_cluster + empty_size);
7679                                 goto have_block_group;
7680                         }
7681
7682                         /*
7683                          * at this point we either didn't find a cluster
7684                          * or we weren't able to allocate a block from our
7685                          * cluster.  Free the cluster we've been trying
7686                          * to use, and go to the next block group
7687                          */
7688                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7689                         spin_unlock(&last_ptr->refill_lock);
7690                         goto loop;
7691                 }
7692
7693 unclustered_alloc:
7694                 /*
7695                  * We are doing an unclustered alloc, set the fragmented flag so
7696                  * we don't bother trying to setup a cluster again until we get
7697                  * more space.
7698                  */
7699                 if (unlikely(last_ptr)) {
7700                         spin_lock(&last_ptr->lock);
7701                         last_ptr->fragmented = 1;
7702                         spin_unlock(&last_ptr->lock);
7703                 }
7704                 if (cached) {
7705                         struct btrfs_free_space_ctl *ctl =
7706                                 block_group->free_space_ctl;
7707
7708                         spin_lock(&ctl->tree_lock);
7709                         if (ctl->free_space <
7710                             num_bytes + empty_cluster + empty_size) {
7711                                 if (ctl->free_space > max_extent_size)
7712                                         max_extent_size = ctl->free_space;
7713                                 spin_unlock(&ctl->tree_lock);
7714                                 goto loop;
7715                         }
7716                         spin_unlock(&ctl->tree_lock);
7717                 }
7718
7719                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7720                                                     num_bytes, empty_size,
7721                                                     &max_extent_size);
7722                 /*
7723                  * If we didn't find a chunk, and we haven't failed on this
7724                  * block group before, and this block group is in the middle of
7725                  * caching and we are ok with waiting, then go ahead and wait
7726                  * for progress to be made, and set failed_alloc to true.
7727                  *
7728                  * If failed_alloc is true then we've already waited on this
7729                  * block group once and should move on to the next block group.
7730                  */
7731                 if (!offset && !failed_alloc && !cached &&
7732                     loop > LOOP_CACHING_NOWAIT) {
7733                         wait_block_group_cache_progress(block_group,
7734                                                 num_bytes + empty_size);
7735                         failed_alloc = true;
7736                         goto have_block_group;
7737                 } else if (!offset) {
7738                         goto loop;
7739                 }
7740 checks:
7741                 search_start = ALIGN(offset, fs_info->stripesize);
7742
7743                 /* move on to the next group */
7744                 if (search_start + num_bytes >
7745                     block_group->key.objectid + block_group->key.offset) {
7746                         btrfs_add_free_space(block_group, offset, num_bytes);
7747                         goto loop;
7748                 }
7749
7750                 if (offset < search_start)
7751                         btrfs_add_free_space(block_group, offset,
7752                                              search_start - offset);
7753                 BUG_ON(offset > search_start);
7754
7755                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7756                                 num_bytes, delalloc);
7757                 if (ret == -EAGAIN) {
7758                         btrfs_add_free_space(block_group, offset, num_bytes);
7759                         goto loop;
7760                 }
7761                 btrfs_inc_block_group_reservations(block_group);
7762
7763                 /* we are all good, lets return */
7764                 ins->objectid = search_start;
7765                 ins->offset = num_bytes;
7766
7767                 trace_btrfs_reserve_extent(block_group, search_start, num_bytes);
7768                 btrfs_release_block_group(block_group, delalloc);
7769                 break;
7770 loop:
7771                 failed_cluster_refill = false;
7772                 failed_alloc = false;
7773                 BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
7774                        index);
7775                 btrfs_release_block_group(block_group, delalloc);
7776                 cond_resched();
7777         }
7778         up_read(&space_info->groups_sem);
7779
7780         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7781                 && !orig_have_caching_bg)
7782                 orig_have_caching_bg = true;
7783
7784         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7785                 goto search;
7786
7787         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7788                 goto search;
7789
7790         /*
7791          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7792          *                      caching kthreads as we move along
7793          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7794          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7795          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7796          *                      again
7797          */
7798         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7799                 index = 0;
7800                 if (loop == LOOP_CACHING_NOWAIT) {
7801                         /*
7802                          * We want to skip the LOOP_CACHING_WAIT step if we
7803                          * don't have any uncached bgs and we've already done a
7804                          * full search through.
7805                          */
7806                         if (orig_have_caching_bg || !full_search)
7807                                 loop = LOOP_CACHING_WAIT;
7808                         else
7809                                 loop = LOOP_ALLOC_CHUNK;
7810                 } else {
7811                         loop++;
7812                 }
7813
7814                 if (loop == LOOP_ALLOC_CHUNK) {
7815                         struct btrfs_trans_handle *trans;
7816                         int exist = 0;
7817
7818                         trans = current->journal_info;
7819                         if (trans)
7820                                 exist = 1;
7821                         else
7822                                 trans = btrfs_join_transaction(root);
7823
7824                         if (IS_ERR(trans)) {
7825                                 ret = PTR_ERR(trans);
7826                                 goto out;
7827                         }
7828
7829                         ret = do_chunk_alloc(trans, fs_info, flags,
7830                                              CHUNK_ALLOC_FORCE);
7831
7832                         /*
7833                          * If we can't allocate a new chunk we've already looped
7834                          * through at least once, move on to the NO_EMPTY_SIZE
7835                          * case.
7836                          */
7837                         if (ret == -ENOSPC)
7838                                 loop = LOOP_NO_EMPTY_SIZE;
7839
7840                         /*
7841                          * Do not bail out on ENOSPC since we
7842                          * can do more things.
7843                          */
7844                         if (ret < 0 && ret != -ENOSPC)
7845                                 btrfs_abort_transaction(trans, ret);
7846                         else
7847                                 ret = 0;
7848                         if (!exist)
7849                                 btrfs_end_transaction(trans);
7850                         if (ret)
7851                                 goto out;
7852                 }
7853
7854                 if (loop == LOOP_NO_EMPTY_SIZE) {
7855                         /*
7856                          * Don't loop again if we already have no empty_size and
7857                          * no empty_cluster.
7858                          */
7859                         if (empty_size == 0 &&
7860                             empty_cluster == 0) {
7861                                 ret = -ENOSPC;
7862                                 goto out;
7863                         }
7864                         empty_size = 0;
7865                         empty_cluster = 0;
7866                 }
7867
7868                 goto search;
7869         } else if (!ins->objectid) {
7870                 ret = -ENOSPC;
7871         } else if (ins->objectid) {
7872                 if (!use_cluster && last_ptr) {
7873                         spin_lock(&last_ptr->lock);
7874                         last_ptr->window_start = ins->objectid;
7875                         spin_unlock(&last_ptr->lock);
7876                 }
7877                 ret = 0;
7878         }
7879 out:
7880         if (ret == -ENOSPC) {
7881                 spin_lock(&space_info->lock);
7882                 space_info->max_extent_size = max_extent_size;
7883                 spin_unlock(&space_info->lock);
7884                 ins->offset = max_extent_size;
7885         }
7886         return ret;
7887 }
7888
7889 static void dump_space_info(struct btrfs_fs_info *fs_info,
7890                             struct btrfs_space_info *info, u64 bytes,
7891                             int dump_block_groups)
7892 {
7893         struct btrfs_block_group_cache *cache;
7894         int index = 0;
7895
7896         spin_lock(&info->lock);
7897         btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
7898                    info->flags,
7899                    info->total_bytes - btrfs_space_info_used(info, true),
7900                    info->full ? "" : "not ");
7901         btrfs_info(fs_info,
7902                 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
7903                 info->total_bytes, info->bytes_used, info->bytes_pinned,
7904                 info->bytes_reserved, info->bytes_may_use,
7905                 info->bytes_readonly);
7906         spin_unlock(&info->lock);
7907
7908         if (!dump_block_groups)
7909                 return;
7910
7911         down_read(&info->groups_sem);
7912 again:
7913         list_for_each_entry(cache, &info->block_groups[index], list) {
7914                 spin_lock(&cache->lock);
7915                 btrfs_info(fs_info,
7916                         "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
7917                         cache->key.objectid, cache->key.offset,
7918                         btrfs_block_group_used(&cache->item), cache->pinned,
7919                         cache->reserved, cache->ro ? "[readonly]" : "");
7920                 btrfs_dump_free_space(cache, bytes);
7921                 spin_unlock(&cache->lock);
7922         }
7923         if (++index < BTRFS_NR_RAID_TYPES)
7924                 goto again;
7925         up_read(&info->groups_sem);
7926 }
7927
7928 /*
7929  * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
7930  *                        hole that is at least as big as @num_bytes.
7931  *
7932  * @root           -    The root that will contain this extent
7933  *
7934  * @ram_bytes      -    The amount of space in ram that @num_bytes take. This
7935  *                      is used for accounting purposes. This value differs
7936  *                      from @num_bytes only in the case of compressed extents.
7937  *
7938  * @num_bytes      -    Number of bytes to allocate on-disk.
7939  *
7940  * @min_alloc_size -    Indicates the minimum amount of space that the
7941  *                      allocator should try to satisfy. In some cases
7942  *                      @num_bytes may be larger than what is required and if
7943  *                      the filesystem is fragmented then allocation fails.
7944  *                      However, the presence of @min_alloc_size gives a
7945  *                      chance to try and satisfy the smaller allocation.
7946  *
7947  * @empty_size     -    A hint that you plan on doing more COW. This is the
7948  *                      size in bytes the allocator should try to find free
7949  *                      next to the block it returns.  This is just a hint and
7950  *                      may be ignored by the allocator.
7951  *
7952  * @hint_byte      -    Hint to the allocator to start searching above the byte
7953  *                      address passed. It might be ignored.
7954  *
7955  * @ins            -    This key is modified to record the found hole. It will
7956  *                      have the following values:
7957  *                      ins->objectid == start position
7958  *                      ins->flags = BTRFS_EXTENT_ITEM_KEY
7959  *                      ins->offset == the size of the hole.
7960  *
7961  * @is_data        -    Boolean flag indicating whether an extent is
7962  *                      allocated for data (true) or metadata (false)
7963  *
7964  * @delalloc       -    Boolean flag indicating whether this allocation is for
7965  *                      delalloc or not. If 'true' data_rwsem of block groups
7966  *                      is going to be acquired.
7967  *
7968  *
7969  * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
7970  * case -ENOSPC is returned then @ins->offset will contain the size of the
7971  * largest available hole the allocator managed to find.
7972  */
7973 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
7974                          u64 num_bytes, u64 min_alloc_size,
7975                          u64 empty_size, u64 hint_byte,
7976                          struct btrfs_key *ins, int is_data, int delalloc)
7977 {
7978         struct btrfs_fs_info *fs_info = root->fs_info;
7979         bool final_tried = num_bytes == min_alloc_size;
7980         u64 flags;
7981         int ret;
7982
7983         flags = get_alloc_profile_by_root(root, is_data);
7984 again:
7985         WARN_ON(num_bytes < fs_info->sectorsize);
7986         ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
7987                                hint_byte, ins, flags, delalloc);
7988         if (!ret && !is_data) {
7989                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
7990         } else if (ret == -ENOSPC) {
7991                 if (!final_tried && ins->offset) {
7992                         num_bytes = min(num_bytes >> 1, ins->offset);
7993                         num_bytes = round_down(num_bytes,
7994                                                fs_info->sectorsize);
7995                         num_bytes = max(num_bytes, min_alloc_size);
7996                         ram_bytes = num_bytes;
7997                         if (num_bytes == min_alloc_size)
7998                                 final_tried = true;
7999                         goto again;
8000                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8001                         struct btrfs_space_info *sinfo;
8002
8003                         sinfo = __find_space_info(fs_info, flags);
8004                         btrfs_err(fs_info,
8005                                   "allocation failed flags %llu, wanted %llu",
8006                                   flags, num_bytes);
8007                         if (sinfo)
8008                                 dump_space_info(fs_info, sinfo, num_bytes, 1);
8009                 }
8010         }
8011
8012         return ret;
8013 }
8014
8015 static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8016                                         u64 start, u64 len,
8017                                         int pin, int delalloc)
8018 {
8019         struct btrfs_block_group_cache *cache;
8020         int ret = 0;
8021
8022         cache = btrfs_lookup_block_group(fs_info, start);
8023         if (!cache) {
8024                 btrfs_err(fs_info, "Unable to find block group for %llu",
8025                           start);
8026                 return -ENOSPC;
8027         }
8028
8029         if (pin)
8030                 pin_down_extent(fs_info, cache, start, len, 1);
8031         else {
8032                 if (btrfs_test_opt(fs_info, DISCARD))
8033                         ret = btrfs_discard_extent(fs_info, start, len, NULL);
8034                 btrfs_add_free_space(cache, start, len);
8035                 btrfs_free_reserved_bytes(cache, len, delalloc);
8036                 trace_btrfs_reserved_extent_free(fs_info, start, len);
8037         }
8038
8039         btrfs_put_block_group(cache);
8040         return ret;
8041 }
8042
8043 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8044                                u64 start, u64 len, int delalloc)
8045 {
8046         return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
8047 }
8048
8049 int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
8050                                        u64 start, u64 len)
8051 {
8052         return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
8053 }
8054
8055 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8056                                       struct btrfs_fs_info *fs_info,
8057                                       u64 parent, u64 root_objectid,
8058                                       u64 flags, u64 owner, u64 offset,
8059                                       struct btrfs_key *ins, int ref_mod)
8060 {
8061         int ret;
8062         struct btrfs_extent_item *extent_item;
8063         struct btrfs_extent_inline_ref *iref;
8064         struct btrfs_path *path;
8065         struct extent_buffer *leaf;
8066         int type;
8067         u32 size;
8068
8069         if (parent > 0)
8070                 type = BTRFS_SHARED_DATA_REF_KEY;
8071         else
8072                 type = BTRFS_EXTENT_DATA_REF_KEY;
8073
8074         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8075
8076         path = btrfs_alloc_path();
8077         if (!path)
8078                 return -ENOMEM;
8079
8080         path->leave_spinning = 1;
8081         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8082                                       ins, size);
8083         if (ret) {
8084                 btrfs_free_path(path);
8085                 return ret;
8086         }
8087
8088         leaf = path->nodes[0];
8089         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8090                                      struct btrfs_extent_item);
8091         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8092         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8093         btrfs_set_extent_flags(leaf, extent_item,
8094                                flags | BTRFS_EXTENT_FLAG_DATA);
8095
8096         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8097         btrfs_set_extent_inline_ref_type(leaf, iref, type);
8098         if (parent > 0) {
8099                 struct btrfs_shared_data_ref *ref;
8100                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8101                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8102                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8103         } else {
8104                 struct btrfs_extent_data_ref *ref;
8105                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8106                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8107                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8108                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8109                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8110         }
8111
8112         btrfs_mark_buffer_dirty(path->nodes[0]);
8113         btrfs_free_path(path);
8114
8115         ret = remove_from_free_space_tree(trans, ins->objectid, ins->offset);
8116         if (ret)
8117                 return ret;
8118
8119         ret = update_block_group(trans, fs_info, ins->objectid, ins->offset, 1);
8120         if (ret) { /* -ENOENT, logic error */
8121                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8122                         ins->objectid, ins->offset);
8123                 BUG();
8124         }
8125         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
8126         return ret;
8127 }
8128
8129 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8130                                      struct btrfs_delayed_ref_node *node,
8131                                      struct btrfs_delayed_extent_op *extent_op)
8132 {
8133         struct btrfs_fs_info *fs_info = trans->fs_info;
8134         int ret;
8135         struct btrfs_extent_item *extent_item;
8136         struct btrfs_key extent_key;
8137         struct btrfs_tree_block_info *block_info;
8138         struct btrfs_extent_inline_ref *iref;
8139         struct btrfs_path *path;
8140         struct extent_buffer *leaf;
8141         struct btrfs_delayed_tree_ref *ref;
8142         u32 size = sizeof(*extent_item) + sizeof(*iref);
8143         u64 num_bytes;
8144         u64 flags = extent_op->flags_to_set;
8145         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8146
8147         ref = btrfs_delayed_node_to_tree_ref(node);
8148
8149         extent_key.objectid = node->bytenr;
8150         if (skinny_metadata) {
8151                 extent_key.offset = ref->level;
8152                 extent_key.type = BTRFS_METADATA_ITEM_KEY;
8153                 num_bytes = fs_info->nodesize;
8154         } else {
8155                 extent_key.offset = node->num_bytes;
8156                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
8157                 size += sizeof(*block_info);
8158                 num_bytes = node->num_bytes;
8159         }
8160
8161         path = btrfs_alloc_path();
8162         if (!path) {
8163                 btrfs_free_and_pin_reserved_extent(fs_info,
8164                                                    extent_key.objectid,
8165                                                    fs_info->nodesize);
8166                 return -ENOMEM;
8167         }
8168
8169         path->leave_spinning = 1;
8170         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8171                                       &extent_key, size);
8172         if (ret) {
8173                 btrfs_free_path(path);
8174                 btrfs_free_and_pin_reserved_extent(fs_info,
8175                                                    extent_key.objectid,
8176                                                    fs_info->nodesize);
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, 1);
8184         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8185         btrfs_set_extent_flags(leaf, extent_item,
8186                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8187
8188         if (skinny_metadata) {
8189                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8190         } else {
8191                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8192                 btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
8193                 btrfs_set_tree_block_level(leaf, block_info, ref->level);
8194                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8195         }
8196
8197         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
8198                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8199                 btrfs_set_extent_inline_ref_type(leaf, iref,
8200                                                  BTRFS_SHARED_BLOCK_REF_KEY);
8201                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
8202         } else {
8203                 btrfs_set_extent_inline_ref_type(leaf, iref,
8204                                                  BTRFS_TREE_BLOCK_REF_KEY);
8205                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
8206         }
8207
8208         btrfs_mark_buffer_dirty(leaf);
8209         btrfs_free_path(path);
8210
8211         ret = remove_from_free_space_tree(trans, extent_key.objectid,
8212                                           num_bytes);
8213         if (ret)
8214                 return ret;
8215
8216         ret = update_block_group(trans, fs_info, extent_key.objectid,
8217                                  fs_info->nodesize, 1);
8218         if (ret) { /* -ENOENT, logic error */
8219                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8220                         extent_key.objectid, extent_key.offset);
8221                 BUG();
8222         }
8223
8224         trace_btrfs_reserved_extent_alloc(fs_info, extent_key.objectid,
8225                                           fs_info->nodesize);
8226         return ret;
8227 }
8228
8229 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8230                                      struct btrfs_root *root, u64 owner,
8231                                      u64 offset, u64 ram_bytes,
8232                                      struct btrfs_key *ins)
8233 {
8234         struct btrfs_fs_info *fs_info = root->fs_info;
8235         int ret;
8236
8237         BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
8238
8239         btrfs_ref_tree_mod(root, ins->objectid, ins->offset, 0,
8240                            root->root_key.objectid, owner, offset,
8241                            BTRFS_ADD_DELAYED_EXTENT);
8242
8243         ret = btrfs_add_delayed_data_ref(fs_info, trans, ins->objectid,
8244                                          ins->offset, 0,
8245                                          root->root_key.objectid, owner,
8246                                          offset, ram_bytes,
8247                                          BTRFS_ADD_DELAYED_EXTENT, NULL, NULL);
8248         return ret;
8249 }
8250
8251 /*
8252  * this is used by the tree logging recovery code.  It records that
8253  * an extent has been allocated and makes sure to clear the free
8254  * space cache bits as well
8255  */
8256 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8257                                    struct btrfs_fs_info *fs_info,
8258                                    u64 root_objectid, u64 owner, u64 offset,
8259                                    struct btrfs_key *ins)
8260 {
8261         int ret;
8262         struct btrfs_block_group_cache *block_group;
8263         struct btrfs_space_info *space_info;
8264
8265         /*
8266          * Mixed block groups will exclude before processing the log so we only
8267          * need to do the exclude dance if this fs isn't mixed.
8268          */
8269         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
8270                 ret = __exclude_logged_extent(fs_info, ins->objectid,
8271                                               ins->offset);
8272                 if (ret)
8273                         return ret;
8274         }
8275
8276         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
8277         if (!block_group)
8278                 return -EINVAL;
8279
8280         space_info = block_group->space_info;
8281         spin_lock(&space_info->lock);
8282         spin_lock(&block_group->lock);
8283         space_info->bytes_reserved += ins->offset;
8284         block_group->reserved += ins->offset;
8285         spin_unlock(&block_group->lock);
8286         spin_unlock(&space_info->lock);
8287
8288         ret = alloc_reserved_file_extent(trans, fs_info, 0, root_objectid,
8289                                          0, owner, offset, ins, 1);
8290         btrfs_put_block_group(block_group);
8291         return ret;
8292 }
8293
8294 static struct extent_buffer *
8295 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8296                       u64 bytenr, int level)
8297 {
8298         struct btrfs_fs_info *fs_info = root->fs_info;
8299         struct extent_buffer *buf;
8300
8301         buf = btrfs_find_create_tree_block(fs_info, bytenr);
8302         if (IS_ERR(buf))
8303                 return buf;
8304
8305         btrfs_set_header_generation(buf, trans->transid);
8306         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8307         btrfs_tree_lock(buf);
8308         clean_tree_block(fs_info, buf);
8309         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8310
8311         btrfs_set_lock_blocking(buf);
8312         set_extent_buffer_uptodate(buf);
8313
8314         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8315                 buf->log_index = root->log_transid % 2;
8316                 /*
8317                  * we allow two log transactions at a time, use different
8318                  * EXENT bit to differentiate dirty pages.
8319                  */
8320                 if (buf->log_index == 0)
8321                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8322                                         buf->start + buf->len - 1, GFP_NOFS);
8323                 else
8324                         set_extent_new(&root->dirty_log_pages, buf->start,
8325                                         buf->start + buf->len - 1);
8326         } else {
8327                 buf->log_index = -1;
8328                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8329                          buf->start + buf->len - 1, GFP_NOFS);
8330         }
8331         trans->dirty = true;
8332         /* this returns a buffer locked for blocking */
8333         return buf;
8334 }
8335
8336 static struct btrfs_block_rsv *
8337 use_block_rsv(struct btrfs_trans_handle *trans,
8338               struct btrfs_root *root, u32 blocksize)
8339 {
8340         struct btrfs_fs_info *fs_info = root->fs_info;
8341         struct btrfs_block_rsv *block_rsv;
8342         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
8343         int ret;
8344         bool global_updated = false;
8345
8346         block_rsv = get_block_rsv(trans, root);
8347
8348         if (unlikely(block_rsv->size == 0))
8349                 goto try_reserve;
8350 again:
8351         ret = block_rsv_use_bytes(block_rsv, blocksize);
8352         if (!ret)
8353                 return block_rsv;
8354
8355         if (block_rsv->failfast)
8356                 return ERR_PTR(ret);
8357
8358         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8359                 global_updated = true;
8360                 update_global_block_rsv(fs_info);
8361                 goto again;
8362         }
8363
8364         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8365                 static DEFINE_RATELIMIT_STATE(_rs,
8366                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8367                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8368                 if (__ratelimit(&_rs))
8369                         WARN(1, KERN_DEBUG
8370                                 "BTRFS: block rsv returned %d\n", ret);
8371         }
8372 try_reserve:
8373         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8374                                      BTRFS_RESERVE_NO_FLUSH);
8375         if (!ret)
8376                 return block_rsv;
8377         /*
8378          * If we couldn't reserve metadata bytes try and use some from
8379          * the global reserve if its space type is the same as the global
8380          * reservation.
8381          */
8382         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8383             block_rsv->space_info == global_rsv->space_info) {
8384                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8385                 if (!ret)
8386                         return global_rsv;
8387         }
8388         return ERR_PTR(ret);
8389 }
8390
8391 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8392                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8393 {
8394         block_rsv_add_bytes(block_rsv, blocksize, 0);
8395         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0, NULL);
8396 }
8397
8398 /*
8399  * finds a free extent and does all the dirty work required for allocation
8400  * returns the tree buffer or an ERR_PTR on error.
8401  */
8402 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8403                                              struct btrfs_root *root,
8404                                              u64 parent, u64 root_objectid,
8405                                              const struct btrfs_disk_key *key,
8406                                              int level, u64 hint,
8407                                              u64 empty_size)
8408 {
8409         struct btrfs_fs_info *fs_info = root->fs_info;
8410         struct btrfs_key ins;
8411         struct btrfs_block_rsv *block_rsv;
8412         struct extent_buffer *buf;
8413         struct btrfs_delayed_extent_op *extent_op;
8414         u64 flags = 0;
8415         int ret;
8416         u32 blocksize = fs_info->nodesize;
8417         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8418
8419 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8420         if (btrfs_is_testing(fs_info)) {
8421                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8422                                             level);
8423                 if (!IS_ERR(buf))
8424                         root->alloc_bytenr += blocksize;
8425                 return buf;
8426         }
8427 #endif
8428
8429         block_rsv = use_block_rsv(trans, root, blocksize);
8430         if (IS_ERR(block_rsv))
8431                 return ERR_CAST(block_rsv);
8432
8433         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8434                                    empty_size, hint, &ins, 0, 0);
8435         if (ret)
8436                 goto out_unuse;
8437
8438         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8439         if (IS_ERR(buf)) {
8440                 ret = PTR_ERR(buf);
8441                 goto out_free_reserved;
8442         }
8443
8444         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8445                 if (parent == 0)
8446                         parent = ins.objectid;
8447                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8448         } else
8449                 BUG_ON(parent > 0);
8450
8451         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8452                 extent_op = btrfs_alloc_delayed_extent_op();
8453                 if (!extent_op) {
8454                         ret = -ENOMEM;
8455                         goto out_free_buf;
8456                 }
8457                 if (key)
8458                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8459                 else
8460                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8461                 extent_op->flags_to_set = flags;
8462                 extent_op->update_key = skinny_metadata ? false : true;
8463                 extent_op->update_flags = true;
8464                 extent_op->is_data = false;
8465                 extent_op->level = level;
8466
8467                 btrfs_ref_tree_mod(root, ins.objectid, ins.offset, parent,
8468                                    root_objectid, level, 0,
8469                                    BTRFS_ADD_DELAYED_EXTENT);
8470                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, ins.objectid,
8471                                                  ins.offset, parent,
8472                                                  root_objectid, level,
8473                                                  BTRFS_ADD_DELAYED_EXTENT,
8474                                                  extent_op, NULL, NULL);
8475                 if (ret)
8476                         goto out_free_delayed;
8477         }
8478         return buf;
8479
8480 out_free_delayed:
8481         btrfs_free_delayed_extent_op(extent_op);
8482 out_free_buf:
8483         free_extent_buffer(buf);
8484 out_free_reserved:
8485         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
8486 out_unuse:
8487         unuse_block_rsv(fs_info, block_rsv, blocksize);
8488         return ERR_PTR(ret);
8489 }
8490
8491 struct walk_control {
8492         u64 refs[BTRFS_MAX_LEVEL];
8493         u64 flags[BTRFS_MAX_LEVEL];
8494         struct btrfs_key update_progress;
8495         int stage;
8496         int level;
8497         int shared_level;
8498         int update_ref;
8499         int keep_locks;
8500         int reada_slot;
8501         int reada_count;
8502         int for_reloc;
8503 };
8504
8505 #define DROP_REFERENCE  1
8506 #define UPDATE_BACKREF  2
8507
8508 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8509                                      struct btrfs_root *root,
8510                                      struct walk_control *wc,
8511                                      struct btrfs_path *path)
8512 {
8513         struct btrfs_fs_info *fs_info = root->fs_info;
8514         u64 bytenr;
8515         u64 generation;
8516         u64 refs;
8517         u64 flags;
8518         u32 nritems;
8519         struct btrfs_key key;
8520         struct extent_buffer *eb;
8521         int ret;
8522         int slot;
8523         int nread = 0;
8524
8525         if (path->slots[wc->level] < wc->reada_slot) {
8526                 wc->reada_count = wc->reada_count * 2 / 3;
8527                 wc->reada_count = max(wc->reada_count, 2);
8528         } else {
8529                 wc->reada_count = wc->reada_count * 3 / 2;
8530                 wc->reada_count = min_t(int, wc->reada_count,
8531                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
8532         }
8533
8534         eb = path->nodes[wc->level];
8535         nritems = btrfs_header_nritems(eb);
8536
8537         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8538                 if (nread >= wc->reada_count)
8539                         break;
8540
8541                 cond_resched();
8542                 bytenr = btrfs_node_blockptr(eb, slot);
8543                 generation = btrfs_node_ptr_generation(eb, slot);
8544
8545                 if (slot == path->slots[wc->level])
8546                         goto reada;
8547
8548                 if (wc->stage == UPDATE_BACKREF &&
8549                     generation <= root->root_key.offset)
8550                         continue;
8551
8552                 /* We don't lock the tree block, it's OK to be racy here */
8553                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
8554                                                wc->level - 1, 1, &refs,
8555                                                &flags);
8556                 /* We don't care about errors in readahead. */
8557                 if (ret < 0)
8558                         continue;
8559                 BUG_ON(refs == 0);
8560
8561                 if (wc->stage == DROP_REFERENCE) {
8562                         if (refs == 1)
8563                                 goto reada;
8564
8565                         if (wc->level == 1 &&
8566                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8567                                 continue;
8568                         if (!wc->update_ref ||
8569                             generation <= root->root_key.offset)
8570                                 continue;
8571                         btrfs_node_key_to_cpu(eb, &key, slot);
8572                         ret = btrfs_comp_cpu_keys(&key,
8573                                                   &wc->update_progress);
8574                         if (ret < 0)
8575                                 continue;
8576                 } else {
8577                         if (wc->level == 1 &&
8578                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8579                                 continue;
8580                 }
8581 reada:
8582                 readahead_tree_block(fs_info, bytenr);
8583                 nread++;
8584         }
8585         wc->reada_slot = slot;
8586 }
8587
8588 /*
8589  * helper to process tree block while walking down the tree.
8590  *
8591  * when wc->stage == UPDATE_BACKREF, this function updates
8592  * back refs for pointers in the block.
8593  *
8594  * NOTE: return value 1 means we should stop walking down.
8595  */
8596 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8597                                    struct btrfs_root *root,
8598                                    struct btrfs_path *path,
8599                                    struct walk_control *wc, int lookup_info)
8600 {
8601         struct btrfs_fs_info *fs_info = root->fs_info;
8602         int level = wc->level;
8603         struct extent_buffer *eb = path->nodes[level];
8604         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8605         int ret;
8606
8607         if (wc->stage == UPDATE_BACKREF &&
8608             btrfs_header_owner(eb) != root->root_key.objectid)
8609                 return 1;
8610
8611         /*
8612          * when reference count of tree block is 1, it won't increase
8613          * again. once full backref flag is set, we never clear it.
8614          */
8615         if (lookup_info &&
8616             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8617              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8618                 BUG_ON(!path->locks[level]);
8619                 ret = btrfs_lookup_extent_info(trans, fs_info,
8620                                                eb->start, level, 1,
8621                                                &wc->refs[level],
8622                                                &wc->flags[level]);
8623                 BUG_ON(ret == -ENOMEM);
8624                 if (ret)
8625                         return ret;
8626                 BUG_ON(wc->refs[level] == 0);
8627         }
8628
8629         if (wc->stage == DROP_REFERENCE) {
8630                 if (wc->refs[level] > 1)
8631                         return 1;
8632
8633                 if (path->locks[level] && !wc->keep_locks) {
8634                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8635                         path->locks[level] = 0;
8636                 }
8637                 return 0;
8638         }
8639
8640         /* wc->stage == UPDATE_BACKREF */
8641         if (!(wc->flags[level] & flag)) {
8642                 BUG_ON(!path->locks[level]);
8643                 ret = btrfs_inc_ref(trans, root, eb, 1);
8644                 BUG_ON(ret); /* -ENOMEM */
8645                 ret = btrfs_dec_ref(trans, root, eb, 0);
8646                 BUG_ON(ret); /* -ENOMEM */
8647                 ret = btrfs_set_disk_extent_flags(trans, fs_info, eb->start,
8648                                                   eb->len, flag,
8649                                                   btrfs_header_level(eb), 0);
8650                 BUG_ON(ret); /* -ENOMEM */
8651                 wc->flags[level] |= flag;
8652         }
8653
8654         /*
8655          * the block is shared by multiple trees, so it's not good to
8656          * keep the tree lock
8657          */
8658         if (path->locks[level] && level > 0) {
8659                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8660                 path->locks[level] = 0;
8661         }
8662         return 0;
8663 }
8664
8665 /*
8666  * helper to process tree block pointer.
8667  *
8668  * when wc->stage == DROP_REFERENCE, this function checks
8669  * reference count of the block pointed to. if the block
8670  * is shared and we need update back refs for the subtree
8671  * rooted at the block, this function changes wc->stage to
8672  * UPDATE_BACKREF. if the block is shared and there is no
8673  * need to update back, this function drops the reference
8674  * to the block.
8675  *
8676  * NOTE: return value 1 means we should stop walking down.
8677  */
8678 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8679                                  struct btrfs_root *root,
8680                                  struct btrfs_path *path,
8681                                  struct walk_control *wc, int *lookup_info)
8682 {
8683         struct btrfs_fs_info *fs_info = root->fs_info;
8684         u64 bytenr;
8685         u64 generation;
8686         u64 parent;
8687         u32 blocksize;
8688         struct btrfs_key key;
8689         struct btrfs_key first_key;
8690         struct extent_buffer *next;
8691         int level = wc->level;
8692         int reada = 0;
8693         int ret = 0;
8694         bool need_account = false;
8695
8696         generation = btrfs_node_ptr_generation(path->nodes[level],
8697                                                path->slots[level]);
8698         /*
8699          * if the lower level block was created before the snapshot
8700          * was created, we know there is no need to update back refs
8701          * for the subtree
8702          */
8703         if (wc->stage == UPDATE_BACKREF &&
8704             generation <= root->root_key.offset) {
8705                 *lookup_info = 1;
8706                 return 1;
8707         }
8708
8709         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8710         btrfs_node_key_to_cpu(path->nodes[level], &first_key,
8711                               path->slots[level]);
8712         blocksize = fs_info->nodesize;
8713
8714         next = find_extent_buffer(fs_info, bytenr);
8715         if (!next) {
8716                 next = btrfs_find_create_tree_block(fs_info, bytenr);
8717                 if (IS_ERR(next))
8718                         return PTR_ERR(next);
8719
8720                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8721                                                level - 1);
8722                 reada = 1;
8723         }
8724         btrfs_tree_lock(next);
8725         btrfs_set_lock_blocking(next);
8726
8727         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
8728                                        &wc->refs[level - 1],
8729                                        &wc->flags[level - 1]);
8730         if (ret < 0)
8731                 goto out_unlock;
8732
8733         if (unlikely(wc->refs[level - 1] == 0)) {
8734                 btrfs_err(fs_info, "Missing references.");
8735                 ret = -EIO;
8736                 goto out_unlock;
8737         }
8738         *lookup_info = 0;
8739
8740         if (wc->stage == DROP_REFERENCE) {
8741                 if (wc->refs[level - 1] > 1) {
8742                         need_account = true;
8743                         if (level == 1 &&
8744                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8745                                 goto skip;
8746
8747                         if (!wc->update_ref ||
8748                             generation <= root->root_key.offset)
8749                                 goto skip;
8750
8751                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8752                                               path->slots[level]);
8753                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8754                         if (ret < 0)
8755                                 goto skip;
8756
8757                         wc->stage = UPDATE_BACKREF;
8758                         wc->shared_level = level - 1;
8759                 }
8760         } else {
8761                 if (level == 1 &&
8762                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8763                         goto skip;
8764         }
8765
8766         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8767                 btrfs_tree_unlock(next);
8768                 free_extent_buffer(next);
8769                 next = NULL;
8770                 *lookup_info = 1;
8771         }
8772
8773         if (!next) {
8774                 if (reada && level == 1)
8775                         reada_walk_down(trans, root, wc, path);
8776                 next = read_tree_block(fs_info, bytenr, generation, level - 1,
8777                                        &first_key);
8778                 if (IS_ERR(next)) {
8779                         return PTR_ERR(next);
8780                 } else if (!extent_buffer_uptodate(next)) {
8781                         free_extent_buffer(next);
8782                         return -EIO;
8783                 }
8784                 btrfs_tree_lock(next);
8785                 btrfs_set_lock_blocking(next);
8786         }
8787
8788         level--;
8789         ASSERT(level == btrfs_header_level(next));
8790         if (level != btrfs_header_level(next)) {
8791                 btrfs_err(root->fs_info, "mismatched level");
8792                 ret = -EIO;
8793                 goto out_unlock;
8794         }
8795         path->nodes[level] = next;
8796         path->slots[level] = 0;
8797         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8798         wc->level = level;
8799         if (wc->level == 1)
8800                 wc->reada_slot = 0;
8801         return 0;
8802 skip:
8803         wc->refs[level - 1] = 0;
8804         wc->flags[level - 1] = 0;
8805         if (wc->stage == DROP_REFERENCE) {
8806                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8807                         parent = path->nodes[level]->start;
8808                 } else {
8809                         ASSERT(root->root_key.objectid ==
8810                                btrfs_header_owner(path->nodes[level]));
8811                         if (root->root_key.objectid !=
8812                             btrfs_header_owner(path->nodes[level])) {
8813                                 btrfs_err(root->fs_info,
8814                                                 "mismatched block owner");
8815                                 ret = -EIO;
8816                                 goto out_unlock;
8817                         }
8818                         parent = 0;
8819                 }
8820
8821                 if (need_account) {
8822                         ret = btrfs_qgroup_trace_subtree(trans, root, next,
8823                                                          generation, level - 1);
8824                         if (ret) {
8825                                 btrfs_err_rl(fs_info,
8826                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8827                                              ret);
8828                         }
8829                 }
8830                 ret = btrfs_free_extent(trans, root, bytenr, blocksize,
8831                                         parent, root->root_key.objectid,
8832                                         level - 1, 0);
8833                 if (ret)
8834                         goto out_unlock;
8835         }
8836
8837         *lookup_info = 1;
8838         ret = 1;
8839
8840 out_unlock:
8841         btrfs_tree_unlock(next);
8842         free_extent_buffer(next);
8843
8844         return ret;
8845 }
8846
8847 /*
8848  * helper to process tree block while walking up the tree.
8849  *
8850  * when wc->stage == DROP_REFERENCE, this function drops
8851  * reference count on the block.
8852  *
8853  * when wc->stage == UPDATE_BACKREF, this function changes
8854  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8855  * to UPDATE_BACKREF previously while processing the block.
8856  *
8857  * NOTE: return value 1 means we should stop walking up.
8858  */
8859 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8860                                  struct btrfs_root *root,
8861                                  struct btrfs_path *path,
8862                                  struct walk_control *wc)
8863 {
8864         struct btrfs_fs_info *fs_info = root->fs_info;
8865         int ret;
8866         int level = wc->level;
8867         struct extent_buffer *eb = path->nodes[level];
8868         u64 parent = 0;
8869
8870         if (wc->stage == UPDATE_BACKREF) {
8871                 BUG_ON(wc->shared_level < level);
8872                 if (level < wc->shared_level)
8873                         goto out;
8874
8875                 ret = find_next_key(path, level + 1, &wc->update_progress);
8876                 if (ret > 0)
8877                         wc->update_ref = 0;
8878
8879                 wc->stage = DROP_REFERENCE;
8880                 wc->shared_level = -1;
8881                 path->slots[level] = 0;
8882
8883                 /*
8884                  * check reference count again if the block isn't locked.
8885                  * we should start walking down the tree again if reference
8886                  * count is one.
8887                  */
8888                 if (!path->locks[level]) {
8889                         BUG_ON(level == 0);
8890                         btrfs_tree_lock(eb);
8891                         btrfs_set_lock_blocking(eb);
8892                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8893
8894                         ret = btrfs_lookup_extent_info(trans, fs_info,
8895                                                        eb->start, level, 1,
8896                                                        &wc->refs[level],
8897                                                        &wc->flags[level]);
8898                         if (ret < 0) {
8899                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8900                                 path->locks[level] = 0;
8901                                 return ret;
8902                         }
8903                         BUG_ON(wc->refs[level] == 0);
8904                         if (wc->refs[level] == 1) {
8905                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8906                                 path->locks[level] = 0;
8907                                 return 1;
8908                         }
8909                 }
8910         }
8911
8912         /* wc->stage == DROP_REFERENCE */
8913         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8914
8915         if (wc->refs[level] == 1) {
8916                 if (level == 0) {
8917                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8918                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8919                         else
8920                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8921                         BUG_ON(ret); /* -ENOMEM */
8922                         ret = btrfs_qgroup_trace_leaf_items(trans, fs_info, eb);
8923                         if (ret) {
8924                                 btrfs_err_rl(fs_info,
8925                                              "error %d accounting leaf items. Quota is out of sync, rescan required.",
8926                                              ret);
8927                         }
8928                 }
8929                 /* make block locked assertion in clean_tree_block happy */
8930                 if (!path->locks[level] &&
8931                     btrfs_header_generation(eb) == trans->transid) {
8932                         btrfs_tree_lock(eb);
8933                         btrfs_set_lock_blocking(eb);
8934                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8935                 }
8936                 clean_tree_block(fs_info, eb);
8937         }
8938
8939         if (eb == root->node) {
8940                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8941                         parent = eb->start;
8942                 else
8943                         BUG_ON(root->root_key.objectid !=
8944                                btrfs_header_owner(eb));
8945         } else {
8946                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8947                         parent = path->nodes[level + 1]->start;
8948                 else
8949                         BUG_ON(root->root_key.objectid !=
8950                                btrfs_header_owner(path->nodes[level + 1]));
8951         }
8952
8953         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8954 out:
8955         wc->refs[level] = 0;
8956         wc->flags[level] = 0;
8957         return 0;
8958 }
8959
8960 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8961                                    struct btrfs_root *root,
8962                                    struct btrfs_path *path,
8963                                    struct walk_control *wc)
8964 {
8965         int level = wc->level;
8966         int lookup_info = 1;
8967         int ret;
8968
8969         while (level >= 0) {
8970                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8971                 if (ret > 0)
8972                         break;
8973
8974                 if (level == 0)
8975                         break;
8976
8977                 if (path->slots[level] >=
8978                     btrfs_header_nritems(path->nodes[level]))
8979                         break;
8980
8981                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8982                 if (ret > 0) {
8983                         path->slots[level]++;
8984                         continue;
8985                 } else if (ret < 0)
8986                         return ret;
8987                 level = wc->level;
8988         }
8989         return 0;
8990 }
8991
8992 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8993                                  struct btrfs_root *root,
8994                                  struct btrfs_path *path,
8995                                  struct walk_control *wc, int max_level)
8996 {
8997         int level = wc->level;
8998         int ret;
8999
9000         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
9001         while (level < max_level && path->nodes[level]) {
9002                 wc->level = level;
9003                 if (path->slots[level] + 1 <
9004                     btrfs_header_nritems(path->nodes[level])) {
9005                         path->slots[level]++;
9006                         return 0;
9007                 } else {
9008                         ret = walk_up_proc(trans, root, path, wc);
9009                         if (ret > 0)
9010                                 return 0;
9011
9012                         if (path->locks[level]) {
9013                                 btrfs_tree_unlock_rw(path->nodes[level],
9014                                                      path->locks[level]);
9015                                 path->locks[level] = 0;
9016                         }
9017                         free_extent_buffer(path->nodes[level]);
9018                         path->nodes[level] = NULL;
9019                         level++;
9020                 }
9021         }
9022         return 1;
9023 }
9024
9025 /*
9026  * drop a subvolume tree.
9027  *
9028  * this function traverses the tree freeing any blocks that only
9029  * referenced by the tree.
9030  *
9031  * when a shared tree block is found. this function decreases its
9032  * reference count by one. if update_ref is true, this function
9033  * also make sure backrefs for the shared block and all lower level
9034  * blocks are properly updated.
9035  *
9036  * If called with for_reloc == 0, may exit early with -EAGAIN
9037  */
9038 int btrfs_drop_snapshot(struct btrfs_root *root,
9039                          struct btrfs_block_rsv *block_rsv, int update_ref,
9040                          int for_reloc)
9041 {
9042         struct btrfs_fs_info *fs_info = root->fs_info;
9043         struct btrfs_path *path;
9044         struct btrfs_trans_handle *trans;
9045         struct btrfs_root *tree_root = fs_info->tree_root;
9046         struct btrfs_root_item *root_item = &root->root_item;
9047         struct walk_control *wc;
9048         struct btrfs_key key;
9049         int err = 0;
9050         int ret;
9051         int level;
9052         bool root_dropped = false;
9053
9054         btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
9055
9056         path = btrfs_alloc_path();
9057         if (!path) {
9058                 err = -ENOMEM;
9059                 goto out;
9060         }
9061
9062         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9063         if (!wc) {
9064                 btrfs_free_path(path);
9065                 err = -ENOMEM;
9066                 goto out;
9067         }
9068
9069         trans = btrfs_start_transaction(tree_root, 0);
9070         if (IS_ERR(trans)) {
9071                 err = PTR_ERR(trans);
9072                 goto out_free;
9073         }
9074
9075         if (block_rsv)
9076                 trans->block_rsv = block_rsv;
9077
9078         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9079                 level = btrfs_header_level(root->node);
9080                 path->nodes[level] = btrfs_lock_root_node(root);
9081                 btrfs_set_lock_blocking(path->nodes[level]);
9082                 path->slots[level] = 0;
9083                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9084                 memset(&wc->update_progress, 0,
9085                        sizeof(wc->update_progress));
9086         } else {
9087                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9088                 memcpy(&wc->update_progress, &key,
9089                        sizeof(wc->update_progress));
9090
9091                 level = root_item->drop_level;
9092                 BUG_ON(level == 0);
9093                 path->lowest_level = level;
9094                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9095                 path->lowest_level = 0;
9096                 if (ret < 0) {
9097                         err = ret;
9098                         goto out_end_trans;
9099                 }
9100                 WARN_ON(ret > 0);
9101
9102                 /*
9103                  * unlock our path, this is safe because only this
9104                  * function is allowed to delete this snapshot
9105                  */
9106                 btrfs_unlock_up_safe(path, 0);
9107
9108                 level = btrfs_header_level(root->node);
9109                 while (1) {
9110                         btrfs_tree_lock(path->nodes[level]);
9111                         btrfs_set_lock_blocking(path->nodes[level]);
9112                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9113
9114                         ret = btrfs_lookup_extent_info(trans, fs_info,
9115                                                 path->nodes[level]->start,
9116                                                 level, 1, &wc->refs[level],
9117                                                 &wc->flags[level]);
9118                         if (ret < 0) {
9119                                 err = ret;
9120                                 goto out_end_trans;
9121                         }
9122                         BUG_ON(wc->refs[level] == 0);
9123
9124                         if (level == root_item->drop_level)
9125                                 break;
9126
9127                         btrfs_tree_unlock(path->nodes[level]);
9128                         path->locks[level] = 0;
9129                         WARN_ON(wc->refs[level] != 1);
9130                         level--;
9131                 }
9132         }
9133
9134         wc->level = level;
9135         wc->shared_level = -1;
9136         wc->stage = DROP_REFERENCE;
9137         wc->update_ref = update_ref;
9138         wc->keep_locks = 0;
9139         wc->for_reloc = for_reloc;
9140         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9141
9142         while (1) {
9143
9144                 ret = walk_down_tree(trans, root, path, wc);
9145                 if (ret < 0) {
9146                         err = ret;
9147                         break;
9148                 }
9149
9150                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9151                 if (ret < 0) {
9152                         err = ret;
9153                         break;
9154                 }
9155
9156                 if (ret > 0) {
9157                         BUG_ON(wc->stage != DROP_REFERENCE);
9158                         break;
9159                 }
9160
9161                 if (wc->stage == DROP_REFERENCE) {
9162                         level = wc->level;
9163                         btrfs_node_key(path->nodes[level],
9164                                        &root_item->drop_progress,
9165                                        path->slots[level]);
9166                         root_item->drop_level = level;
9167                 }
9168
9169                 BUG_ON(wc->level == 0);
9170                 if (btrfs_should_end_transaction(trans) ||
9171                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
9172                         ret = btrfs_update_root(trans, tree_root,
9173                                                 &root->root_key,
9174                                                 root_item);
9175                         if (ret) {
9176                                 btrfs_abort_transaction(trans, ret);
9177                                 err = ret;
9178                                 goto out_end_trans;
9179                         }
9180
9181                         btrfs_end_transaction_throttle(trans);
9182                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
9183                                 btrfs_debug(fs_info,
9184                                             "drop snapshot early exit");
9185                                 err = -EAGAIN;
9186                                 goto out_free;
9187                         }
9188
9189                         trans = btrfs_start_transaction(tree_root, 0);
9190                         if (IS_ERR(trans)) {
9191                                 err = PTR_ERR(trans);
9192                                 goto out_free;
9193                         }
9194                         if (block_rsv)
9195                                 trans->block_rsv = block_rsv;
9196                 }
9197         }
9198         btrfs_release_path(path);
9199         if (err)
9200                 goto out_end_trans;
9201
9202         ret = btrfs_del_root(trans, fs_info, &root->root_key);
9203         if (ret) {
9204                 btrfs_abort_transaction(trans, ret);
9205                 err = ret;
9206                 goto out_end_trans;
9207         }
9208
9209         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9210                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9211                                       NULL, NULL);
9212                 if (ret < 0) {
9213                         btrfs_abort_transaction(trans, ret);
9214                         err = ret;
9215                         goto out_end_trans;
9216                 } else if (ret > 0) {
9217                         /* if we fail to delete the orphan item this time
9218                          * around, it'll get picked up the next time.
9219                          *
9220                          * The most common failure here is just -ENOENT.
9221                          */
9222                         btrfs_del_orphan_item(trans, tree_root,
9223                                               root->root_key.objectid);
9224                 }
9225         }
9226
9227         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9228                 btrfs_add_dropped_root(trans, root);
9229         } else {
9230                 free_extent_buffer(root->node);
9231                 free_extent_buffer(root->commit_root);
9232                 btrfs_put_fs_root(root);
9233         }
9234         root_dropped = true;
9235 out_end_trans:
9236         btrfs_end_transaction_throttle(trans);
9237 out_free:
9238         kfree(wc);
9239         btrfs_free_path(path);
9240 out:
9241         /*
9242          * So if we need to stop dropping the snapshot for whatever reason we
9243          * need to make sure to add it back to the dead root list so that we
9244          * keep trying to do the work later.  This also cleans up roots if we
9245          * don't have it in the radix (like when we recover after a power fail
9246          * or unmount) so we don't leak memory.
9247          */
9248         if (!for_reloc && !root_dropped)
9249                 btrfs_add_dead_root(root);
9250         if (err && err != -EAGAIN)
9251                 btrfs_handle_fs_error(fs_info, err, NULL);
9252         return err;
9253 }
9254
9255 /*
9256  * drop subtree rooted at tree block 'node'.
9257  *
9258  * NOTE: this function will unlock and release tree block 'node'
9259  * only used by relocation code
9260  */
9261 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9262                         struct btrfs_root *root,
9263                         struct extent_buffer *node,
9264                         struct extent_buffer *parent)
9265 {
9266         struct btrfs_fs_info *fs_info = root->fs_info;
9267         struct btrfs_path *path;
9268         struct walk_control *wc;
9269         int level;
9270         int parent_level;
9271         int ret = 0;
9272         int wret;
9273
9274         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9275
9276         path = btrfs_alloc_path();
9277         if (!path)
9278                 return -ENOMEM;
9279
9280         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9281         if (!wc) {
9282                 btrfs_free_path(path);
9283                 return -ENOMEM;
9284         }
9285
9286         btrfs_assert_tree_locked(parent);
9287         parent_level = btrfs_header_level(parent);
9288         extent_buffer_get(parent);
9289         path->nodes[parent_level] = parent;
9290         path->slots[parent_level] = btrfs_header_nritems(parent);
9291
9292         btrfs_assert_tree_locked(node);
9293         level = btrfs_header_level(node);
9294         path->nodes[level] = node;
9295         path->slots[level] = 0;
9296         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9297
9298         wc->refs[parent_level] = 1;
9299         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9300         wc->level = level;
9301         wc->shared_level = -1;
9302         wc->stage = DROP_REFERENCE;
9303         wc->update_ref = 0;
9304         wc->keep_locks = 1;
9305         wc->for_reloc = 1;
9306         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9307
9308         while (1) {
9309                 wret = walk_down_tree(trans, root, path, wc);
9310                 if (wret < 0) {
9311                         ret = wret;
9312                         break;
9313                 }
9314
9315                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9316                 if (wret < 0)
9317                         ret = wret;
9318                 if (wret != 0)
9319                         break;
9320         }
9321
9322         kfree(wc);
9323         btrfs_free_path(path);
9324         return ret;
9325 }
9326
9327 static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
9328 {
9329         u64 num_devices;
9330         u64 stripped;
9331
9332         /*
9333          * if restripe for this chunk_type is on pick target profile and
9334          * return, otherwise do the usual balance
9335          */
9336         stripped = get_restripe_target(fs_info, flags);
9337         if (stripped)
9338                 return extended_to_chunk(stripped);
9339
9340         num_devices = fs_info->fs_devices->rw_devices;
9341
9342         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9343                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9344                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9345
9346         if (num_devices == 1) {
9347                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9348                 stripped = flags & ~stripped;
9349
9350                 /* turn raid0 into single device chunks */
9351                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9352                         return stripped;
9353
9354                 /* turn mirroring into duplication */
9355                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9356                              BTRFS_BLOCK_GROUP_RAID10))
9357                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9358         } else {
9359                 /* they already had raid on here, just return */
9360                 if (flags & stripped)
9361                         return flags;
9362
9363                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9364                 stripped = flags & ~stripped;
9365
9366                 /* switch duplicated blocks with raid1 */
9367                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9368                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9369
9370                 /* this is drive concat, leave it alone */
9371         }
9372
9373         return flags;
9374 }
9375
9376 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9377 {
9378         struct btrfs_space_info *sinfo = cache->space_info;
9379         u64 num_bytes;
9380         u64 min_allocable_bytes;
9381         int ret = -ENOSPC;
9382
9383         /*
9384          * We need some metadata space and system metadata space for
9385          * allocating chunks in some corner cases until we force to set
9386          * it to be readonly.
9387          */
9388         if ((sinfo->flags &
9389              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9390             !force)
9391                 min_allocable_bytes = SZ_1M;
9392         else
9393                 min_allocable_bytes = 0;
9394
9395         spin_lock(&sinfo->lock);
9396         spin_lock(&cache->lock);
9397
9398         if (cache->ro) {
9399                 cache->ro++;
9400                 ret = 0;
9401                 goto out;
9402         }
9403
9404         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9405                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9406
9407         if (btrfs_space_info_used(sinfo, true) + num_bytes +
9408             min_allocable_bytes <= sinfo->total_bytes) {
9409                 sinfo->bytes_readonly += num_bytes;
9410                 cache->ro++;
9411                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9412                 ret = 0;
9413         }
9414 out:
9415         spin_unlock(&cache->lock);
9416         spin_unlock(&sinfo->lock);
9417         return ret;
9418 }
9419
9420 int btrfs_inc_block_group_ro(struct btrfs_fs_info *fs_info,
9421                              struct btrfs_block_group_cache *cache)
9422
9423 {
9424         struct btrfs_trans_handle *trans;
9425         u64 alloc_flags;
9426         int ret;
9427
9428 again:
9429         trans = btrfs_join_transaction(fs_info->extent_root);
9430         if (IS_ERR(trans))
9431                 return PTR_ERR(trans);
9432
9433         /*
9434          * we're not allowed to set block groups readonly after the dirty
9435          * block groups cache has started writing.  If it already started,
9436          * back off and let this transaction commit
9437          */
9438         mutex_lock(&fs_info->ro_block_group_mutex);
9439         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9440                 u64 transid = trans->transid;
9441
9442                 mutex_unlock(&fs_info->ro_block_group_mutex);
9443                 btrfs_end_transaction(trans);
9444
9445                 ret = btrfs_wait_for_commit(fs_info, transid);
9446                 if (ret)
9447                         return ret;
9448                 goto again;
9449         }
9450
9451         /*
9452          * if we are changing raid levels, try to allocate a corresponding
9453          * block group with the new raid level.
9454          */
9455         alloc_flags = update_block_group_flags(fs_info, cache->flags);
9456         if (alloc_flags != cache->flags) {
9457                 ret = do_chunk_alloc(trans, fs_info, alloc_flags,
9458                                      CHUNK_ALLOC_FORCE);
9459                 /*
9460                  * ENOSPC is allowed here, we may have enough space
9461                  * already allocated at the new raid level to
9462                  * carry on
9463                  */
9464                 if (ret == -ENOSPC)
9465                         ret = 0;
9466                 if (ret < 0)
9467                         goto out;
9468         }
9469
9470         ret = inc_block_group_ro(cache, 0);
9471         if (!ret)
9472                 goto out;
9473         alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
9474         ret = do_chunk_alloc(trans, fs_info, alloc_flags,
9475                              CHUNK_ALLOC_FORCE);
9476         if (ret < 0)
9477                 goto out;
9478         ret = inc_block_group_ro(cache, 0);
9479 out:
9480         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9481                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
9482                 mutex_lock(&fs_info->chunk_mutex);
9483                 check_system_chunk(trans, fs_info, alloc_flags);
9484                 mutex_unlock(&fs_info->chunk_mutex);
9485         }
9486         mutex_unlock(&fs_info->ro_block_group_mutex);
9487
9488         btrfs_end_transaction(trans);
9489         return ret;
9490 }
9491
9492 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9493                             struct btrfs_fs_info *fs_info, u64 type)
9494 {
9495         u64 alloc_flags = get_alloc_profile(fs_info, type);
9496
9497         return do_chunk_alloc(trans, fs_info, alloc_flags, CHUNK_ALLOC_FORCE);
9498 }
9499
9500 /*
9501  * helper to account the unused space of all the readonly block group in the
9502  * space_info. takes mirrors into account.
9503  */
9504 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9505 {
9506         struct btrfs_block_group_cache *block_group;
9507         u64 free_bytes = 0;
9508         int factor;
9509
9510         /* It's df, we don't care if it's racy */
9511         if (list_empty(&sinfo->ro_bgs))
9512                 return 0;
9513
9514         spin_lock(&sinfo->lock);
9515         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9516                 spin_lock(&block_group->lock);
9517
9518                 if (!block_group->ro) {
9519                         spin_unlock(&block_group->lock);
9520                         continue;
9521                 }
9522
9523                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9524                                           BTRFS_BLOCK_GROUP_RAID10 |
9525                                           BTRFS_BLOCK_GROUP_DUP))
9526                         factor = 2;
9527                 else
9528                         factor = 1;
9529
9530                 free_bytes += (block_group->key.offset -
9531                                btrfs_block_group_used(&block_group->item)) *
9532                                factor;
9533
9534                 spin_unlock(&block_group->lock);
9535         }
9536         spin_unlock(&sinfo->lock);
9537
9538         return free_bytes;
9539 }
9540
9541 void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
9542 {
9543         struct btrfs_space_info *sinfo = cache->space_info;
9544         u64 num_bytes;
9545
9546         BUG_ON(!cache->ro);
9547
9548         spin_lock(&sinfo->lock);
9549         spin_lock(&cache->lock);
9550         if (!--cache->ro) {
9551                 num_bytes = cache->key.offset - cache->reserved -
9552                             cache->pinned - cache->bytes_super -
9553                             btrfs_block_group_used(&cache->item);
9554                 sinfo->bytes_readonly -= num_bytes;
9555                 list_del_init(&cache->ro_list);
9556         }
9557         spin_unlock(&cache->lock);
9558         spin_unlock(&sinfo->lock);
9559 }
9560
9561 /*
9562  * checks to see if its even possible to relocate this block group.
9563  *
9564  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9565  * ok to go ahead and try.
9566  */
9567 int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)
9568 {
9569         struct btrfs_root *root = fs_info->extent_root;
9570         struct btrfs_block_group_cache *block_group;
9571         struct btrfs_space_info *space_info;
9572         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
9573         struct btrfs_device *device;
9574         struct btrfs_trans_handle *trans;
9575         u64 min_free;
9576         u64 dev_min = 1;
9577         u64 dev_nr = 0;
9578         u64 target;
9579         int debug;
9580         int index;
9581         int full = 0;
9582         int ret = 0;
9583
9584         debug = btrfs_test_opt(fs_info, ENOSPC_DEBUG);
9585
9586         block_group = btrfs_lookup_block_group(fs_info, bytenr);
9587
9588         /* odd, couldn't find the block group, leave it alone */
9589         if (!block_group) {
9590                 if (debug)
9591                         btrfs_warn(fs_info,
9592                                    "can't find block group for bytenr %llu",
9593                                    bytenr);
9594                 return -1;
9595         }
9596
9597         min_free = btrfs_block_group_used(&block_group->item);
9598
9599         /* no bytes used, we're good */
9600         if (!min_free)
9601                 goto out;
9602
9603         space_info = block_group->space_info;
9604         spin_lock(&space_info->lock);
9605
9606         full = space_info->full;
9607
9608         /*
9609          * if this is the last block group we have in this space, we can't
9610          * relocate it unless we're able to allocate a new chunk below.
9611          *
9612          * Otherwise, we need to make sure we have room in the space to handle
9613          * all of the extents from this block group.  If we can, we're good
9614          */
9615         if ((space_info->total_bytes != block_group->key.offset) &&
9616             (btrfs_space_info_used(space_info, false) + min_free <
9617              space_info->total_bytes)) {
9618                 spin_unlock(&space_info->lock);
9619                 goto out;
9620         }
9621         spin_unlock(&space_info->lock);
9622
9623         /*
9624          * ok we don't have enough space, but maybe we have free space on our
9625          * devices to allocate new chunks for relocation, so loop through our
9626          * alloc devices and guess if we have enough space.  if this block
9627          * group is going to be restriped, run checks against the target
9628          * profile instead of the current one.
9629          */
9630         ret = -1;
9631
9632         /*
9633          * index:
9634          *      0: raid10
9635          *      1: raid1
9636          *      2: dup
9637          *      3: raid0
9638          *      4: single
9639          */
9640         target = get_restripe_target(fs_info, block_group->flags);
9641         if (target) {
9642                 index = btrfs_bg_flags_to_raid_index(extended_to_chunk(target));
9643         } else {
9644                 /*
9645                  * this is just a balance, so if we were marked as full
9646                  * we know there is no space for a new chunk
9647                  */
9648                 if (full) {
9649                         if (debug)
9650                                 btrfs_warn(fs_info,
9651                                            "no space to alloc new chunk for block group %llu",
9652                                            block_group->key.objectid);
9653                         goto out;
9654                 }
9655
9656                 index = btrfs_bg_flags_to_raid_index(block_group->flags);
9657         }
9658
9659         if (index == BTRFS_RAID_RAID10) {
9660                 dev_min = 4;
9661                 /* Divide by 2 */
9662                 min_free >>= 1;
9663         } else if (index == BTRFS_RAID_RAID1) {
9664                 dev_min = 2;
9665         } else if (index == BTRFS_RAID_DUP) {
9666                 /* Multiply by 2 */
9667                 min_free <<= 1;
9668         } else if (index == BTRFS_RAID_RAID0) {
9669                 dev_min = fs_devices->rw_devices;
9670                 min_free = div64_u64(min_free, dev_min);
9671         }
9672
9673         /* We need to do this so that we can look at pending chunks */
9674         trans = btrfs_join_transaction(root);
9675         if (IS_ERR(trans)) {
9676                 ret = PTR_ERR(trans);
9677                 goto out;
9678         }
9679
9680         mutex_lock(&fs_info->chunk_mutex);
9681         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9682                 u64 dev_offset;
9683
9684                 /*
9685                  * check to make sure we can actually find a chunk with enough
9686                  * space to fit our block group in.
9687                  */
9688                 if (device->total_bytes > device->bytes_used + min_free &&
9689                     !test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &device->dev_state)) {
9690                         ret = find_free_dev_extent(trans, device, min_free,
9691                                                    &dev_offset, NULL);
9692                         if (!ret)
9693                                 dev_nr++;
9694
9695                         if (dev_nr >= dev_min)
9696                                 break;
9697
9698                         ret = -1;
9699                 }
9700         }
9701         if (debug && ret == -1)
9702                 btrfs_warn(fs_info,
9703                            "no space to allocate a new chunk for block group %llu",
9704                            block_group->key.objectid);
9705         mutex_unlock(&fs_info->chunk_mutex);
9706         btrfs_end_transaction(trans);
9707 out:
9708         btrfs_put_block_group(block_group);
9709         return ret;
9710 }
9711
9712 static int find_first_block_group(struct btrfs_fs_info *fs_info,
9713                                   struct btrfs_path *path,
9714                                   struct btrfs_key *key)
9715 {
9716         struct btrfs_root *root = fs_info->extent_root;
9717         int ret = 0;
9718         struct btrfs_key found_key;
9719         struct extent_buffer *leaf;
9720         int slot;
9721
9722         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9723         if (ret < 0)
9724                 goto out;
9725
9726         while (1) {
9727                 slot = path->slots[0];
9728                 leaf = path->nodes[0];
9729                 if (slot >= btrfs_header_nritems(leaf)) {
9730                         ret = btrfs_next_leaf(root, path);
9731                         if (ret == 0)
9732                                 continue;
9733                         if (ret < 0)
9734                                 goto out;
9735                         break;
9736                 }
9737                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9738
9739                 if (found_key.objectid >= key->objectid &&
9740                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9741                         struct extent_map_tree *em_tree;
9742                         struct extent_map *em;
9743
9744                         em_tree = &root->fs_info->mapping_tree.map_tree;
9745                         read_lock(&em_tree->lock);
9746                         em = lookup_extent_mapping(em_tree, found_key.objectid,
9747                                                    found_key.offset);
9748                         read_unlock(&em_tree->lock);
9749                         if (!em) {
9750                                 btrfs_err(fs_info,
9751                         "logical %llu len %llu found bg but no related chunk",
9752                                           found_key.objectid, found_key.offset);
9753                                 ret = -ENOENT;
9754                         } else {
9755                                 ret = 0;
9756                         }
9757                         free_extent_map(em);
9758                         goto out;
9759                 }
9760                 path->slots[0]++;
9761         }
9762 out:
9763         return ret;
9764 }
9765
9766 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9767 {
9768         struct btrfs_block_group_cache *block_group;
9769         u64 last = 0;
9770
9771         while (1) {
9772                 struct inode *inode;
9773
9774                 block_group = btrfs_lookup_first_block_group(info, last);
9775                 while (block_group) {
9776                         spin_lock(&block_group->lock);
9777                         if (block_group->iref)
9778                                 break;
9779                         spin_unlock(&block_group->lock);
9780                         block_group = next_block_group(info, block_group);
9781                 }
9782                 if (!block_group) {
9783                         if (last == 0)
9784                                 break;
9785                         last = 0;
9786                         continue;
9787                 }
9788
9789                 inode = block_group->inode;
9790                 block_group->iref = 0;
9791                 block_group->inode = NULL;
9792                 spin_unlock(&block_group->lock);
9793                 ASSERT(block_group->io_ctl.inode == NULL);
9794                 iput(inode);
9795                 last = block_group->key.objectid + block_group->key.offset;
9796                 btrfs_put_block_group(block_group);
9797         }
9798 }
9799
9800 /*
9801  * Must be called only after stopping all workers, since we could have block
9802  * group caching kthreads running, and therefore they could race with us if we
9803  * freed the block groups before stopping them.
9804  */
9805 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9806 {
9807         struct btrfs_block_group_cache *block_group;
9808         struct btrfs_space_info *space_info;
9809         struct btrfs_caching_control *caching_ctl;
9810         struct rb_node *n;
9811
9812         down_write(&info->commit_root_sem);
9813         while (!list_empty(&info->caching_block_groups)) {
9814                 caching_ctl = list_entry(info->caching_block_groups.next,
9815                                          struct btrfs_caching_control, list);
9816                 list_del(&caching_ctl->list);
9817                 put_caching_control(caching_ctl);
9818         }
9819         up_write(&info->commit_root_sem);
9820
9821         spin_lock(&info->unused_bgs_lock);
9822         while (!list_empty(&info->unused_bgs)) {
9823                 block_group = list_first_entry(&info->unused_bgs,
9824                                                struct btrfs_block_group_cache,
9825                                                bg_list);
9826                 list_del_init(&block_group->bg_list);
9827                 btrfs_put_block_group(block_group);
9828         }
9829         spin_unlock(&info->unused_bgs_lock);
9830
9831         spin_lock(&info->block_group_cache_lock);
9832         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9833                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9834                                        cache_node);
9835                 rb_erase(&block_group->cache_node,
9836                          &info->block_group_cache_tree);
9837                 RB_CLEAR_NODE(&block_group->cache_node);
9838                 spin_unlock(&info->block_group_cache_lock);
9839
9840                 down_write(&block_group->space_info->groups_sem);
9841                 list_del(&block_group->list);
9842                 up_write(&block_group->space_info->groups_sem);
9843
9844                 /*
9845                  * We haven't cached this block group, which means we could
9846                  * possibly have excluded extents on this block group.
9847                  */
9848                 if (block_group->cached == BTRFS_CACHE_NO ||
9849                     block_group->cached == BTRFS_CACHE_ERROR)
9850                         free_excluded_extents(info, block_group);
9851
9852                 btrfs_remove_free_space_cache(block_group);
9853                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
9854                 ASSERT(list_empty(&block_group->dirty_list));
9855                 ASSERT(list_empty(&block_group->io_list));
9856                 ASSERT(list_empty(&block_group->bg_list));
9857                 ASSERT(atomic_read(&block_group->count) == 1);
9858                 btrfs_put_block_group(block_group);
9859
9860                 spin_lock(&info->block_group_cache_lock);
9861         }
9862         spin_unlock(&info->block_group_cache_lock);
9863
9864         /* now that all the block groups are freed, go through and
9865          * free all the space_info structs.  This is only called during
9866          * the final stages of unmount, and so we know nobody is
9867          * using them.  We call synchronize_rcu() once before we start,
9868          * just to be on the safe side.
9869          */
9870         synchronize_rcu();
9871
9872         release_global_block_rsv(info);
9873
9874         while (!list_empty(&info->space_info)) {
9875                 int i;
9876
9877                 space_info = list_entry(info->space_info.next,
9878                                         struct btrfs_space_info,
9879                                         list);
9880
9881                 /*
9882                  * Do not hide this behind enospc_debug, this is actually
9883                  * important and indicates a real bug if this happens.
9884                  */
9885                 if (WARN_ON(space_info->bytes_pinned > 0 ||
9886                             space_info->bytes_reserved > 0 ||
9887                             space_info->bytes_may_use > 0))
9888                         dump_space_info(info, space_info, 0, 0);
9889                 list_del(&space_info->list);
9890                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9891                         struct kobject *kobj;
9892                         kobj = space_info->block_group_kobjs[i];
9893                         space_info->block_group_kobjs[i] = NULL;
9894                         if (kobj) {
9895                                 kobject_del(kobj);
9896                                 kobject_put(kobj);
9897                         }
9898                 }
9899                 kobject_del(&space_info->kobj);
9900                 kobject_put(&space_info->kobj);
9901         }
9902         return 0;
9903 }
9904
9905 /* link_block_group will queue up kobjects to add when we're reclaim-safe */
9906 void btrfs_add_raid_kobjects(struct btrfs_fs_info *fs_info)
9907 {
9908         struct btrfs_space_info *space_info;
9909         struct raid_kobject *rkobj;
9910         LIST_HEAD(list);
9911         int index;
9912         int ret = 0;
9913
9914         spin_lock(&fs_info->pending_raid_kobjs_lock);
9915         list_splice_init(&fs_info->pending_raid_kobjs, &list);
9916         spin_unlock(&fs_info->pending_raid_kobjs_lock);
9917
9918         list_for_each_entry(rkobj, &list, list) {
9919                 space_info = __find_space_info(fs_info, rkobj->flags);
9920                 index = btrfs_bg_flags_to_raid_index(rkobj->flags);
9921
9922                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9923                                   "%s", get_raid_name(index));
9924                 if (ret) {
9925                         kobject_put(&rkobj->kobj);
9926                         break;
9927                 }
9928         }
9929         if (ret)
9930                 btrfs_warn(fs_info,
9931                            "failed to add kobject for block cache, ignoring");
9932 }
9933
9934 static void link_block_group(struct btrfs_block_group_cache *cache)
9935 {
9936         struct btrfs_space_info *space_info = cache->space_info;
9937         struct btrfs_fs_info *fs_info = cache->fs_info;
9938         int index = btrfs_bg_flags_to_raid_index(cache->flags);
9939         bool first = false;
9940
9941         down_write(&space_info->groups_sem);
9942         if (list_empty(&space_info->block_groups[index]))
9943                 first = true;
9944         list_add_tail(&cache->list, &space_info->block_groups[index]);
9945         up_write(&space_info->groups_sem);
9946
9947         if (first) {
9948                 struct raid_kobject *rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9949                 if (!rkobj) {
9950                         btrfs_warn(cache->fs_info,
9951                                 "couldn't alloc memory for raid level kobject");
9952                         return;
9953                 }
9954                 rkobj->flags = cache->flags;
9955                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9956
9957                 spin_lock(&fs_info->pending_raid_kobjs_lock);
9958                 list_add_tail(&rkobj->list, &fs_info->pending_raid_kobjs);
9959                 spin_unlock(&fs_info->pending_raid_kobjs_lock);
9960                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9961         }
9962 }
9963
9964 static struct btrfs_block_group_cache *
9965 btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
9966                                u64 start, u64 size)
9967 {
9968         struct btrfs_block_group_cache *cache;
9969
9970         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9971         if (!cache)
9972                 return NULL;
9973
9974         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9975                                         GFP_NOFS);
9976         if (!cache->free_space_ctl) {
9977                 kfree(cache);
9978                 return NULL;
9979         }
9980
9981         cache->key.objectid = start;
9982         cache->key.offset = size;
9983         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9984
9985         cache->fs_info = fs_info;
9986         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
9987         set_free_space_tree_thresholds(cache);
9988
9989         atomic_set(&cache->count, 1);
9990         spin_lock_init(&cache->lock);
9991         init_rwsem(&cache->data_rwsem);
9992         INIT_LIST_HEAD(&cache->list);
9993         INIT_LIST_HEAD(&cache->cluster_list);
9994         INIT_LIST_HEAD(&cache->bg_list);
9995         INIT_LIST_HEAD(&cache->ro_list);
9996         INIT_LIST_HEAD(&cache->dirty_list);
9997         INIT_LIST_HEAD(&cache->io_list);
9998         btrfs_init_free_space_ctl(cache);
9999         atomic_set(&cache->trimming, 0);
10000         mutex_init(&cache->free_space_lock);
10001         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
10002
10003         return cache;
10004 }
10005
10006 int btrfs_read_block_groups(struct btrfs_fs_info *info)
10007 {
10008         struct btrfs_path *path;
10009         int ret;
10010         struct btrfs_block_group_cache *cache;
10011         struct btrfs_space_info *space_info;
10012         struct btrfs_key key;
10013         struct btrfs_key found_key;
10014         struct extent_buffer *leaf;
10015         int need_clear = 0;
10016         u64 cache_gen;
10017         u64 feature;
10018         int mixed;
10019
10020         feature = btrfs_super_incompat_flags(info->super_copy);
10021         mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
10022
10023         key.objectid = 0;
10024         key.offset = 0;
10025         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10026         path = btrfs_alloc_path();
10027         if (!path)
10028                 return -ENOMEM;
10029         path->reada = READA_FORWARD;
10030
10031         cache_gen = btrfs_super_cache_generation(info->super_copy);
10032         if (btrfs_test_opt(info, SPACE_CACHE) &&
10033             btrfs_super_generation(info->super_copy) != cache_gen)
10034                 need_clear = 1;
10035         if (btrfs_test_opt(info, CLEAR_CACHE))
10036                 need_clear = 1;
10037
10038         while (1) {
10039                 ret = find_first_block_group(info, path, &key);
10040                 if (ret > 0)
10041                         break;
10042                 if (ret != 0)
10043                         goto error;
10044
10045                 leaf = path->nodes[0];
10046                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10047
10048                 cache = btrfs_create_block_group_cache(info, found_key.objectid,
10049                                                        found_key.offset);
10050                 if (!cache) {
10051                         ret = -ENOMEM;
10052                         goto error;
10053                 }
10054
10055                 if (need_clear) {
10056                         /*
10057                          * When we mount with old space cache, we need to
10058                          * set BTRFS_DC_CLEAR and set dirty flag.
10059                          *
10060                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10061                          *    truncate the old free space cache inode and
10062                          *    setup a new one.
10063                          * b) Setting 'dirty flag' makes sure that we flush
10064                          *    the new space cache info onto disk.
10065                          */
10066                         if (btrfs_test_opt(info, SPACE_CACHE))
10067                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
10068                 }
10069
10070                 read_extent_buffer(leaf, &cache->item,
10071                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
10072                                    sizeof(cache->item));
10073                 cache->flags = btrfs_block_group_flags(&cache->item);
10074                 if (!mixed &&
10075                     ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
10076                     (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
10077                         btrfs_err(info,
10078 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
10079                                   cache->key.objectid);
10080                         ret = -EINVAL;
10081                         goto error;
10082                 }
10083
10084                 key.objectid = found_key.objectid + found_key.offset;
10085                 btrfs_release_path(path);
10086
10087                 /*
10088                  * We need to exclude the super stripes now so that the space
10089                  * info has super bytes accounted for, otherwise we'll think
10090                  * we have more space than we actually do.
10091                  */
10092                 ret = exclude_super_stripes(info, cache);
10093                 if (ret) {
10094                         /*
10095                          * We may have excluded something, so call this just in
10096                          * case.
10097                          */
10098                         free_excluded_extents(info, cache);
10099                         btrfs_put_block_group(cache);
10100                         goto error;
10101                 }
10102
10103                 /*
10104                  * check for two cases, either we are full, and therefore
10105                  * don't need to bother with the caching work since we won't
10106                  * find any space, or we are empty, and we can just add all
10107                  * the space in and be done with it.  This saves us _alot_ of
10108                  * time, particularly in the full case.
10109                  */
10110                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10111                         cache->last_byte_to_unpin = (u64)-1;
10112                         cache->cached = BTRFS_CACHE_FINISHED;
10113                         free_excluded_extents(info, cache);
10114                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10115                         cache->last_byte_to_unpin = (u64)-1;
10116                         cache->cached = BTRFS_CACHE_FINISHED;
10117                         add_new_free_space(cache, found_key.objectid,
10118                                            found_key.objectid +
10119                                            found_key.offset);
10120                         free_excluded_extents(info, cache);
10121                 }
10122
10123                 ret = btrfs_add_block_group_cache(info, cache);
10124                 if (ret) {
10125                         btrfs_remove_free_space_cache(cache);
10126                         btrfs_put_block_group(cache);
10127                         goto error;
10128                 }
10129
10130                 trace_btrfs_add_block_group(info, cache, 0);
10131                 update_space_info(info, cache->flags, found_key.offset,
10132                                   btrfs_block_group_used(&cache->item),
10133                                   cache->bytes_super, &space_info);
10134
10135                 cache->space_info = space_info;
10136
10137                 link_block_group(cache);
10138
10139                 set_avail_alloc_bits(info, cache->flags);
10140                 if (btrfs_chunk_readonly(info, cache->key.objectid)) {
10141                         inc_block_group_ro(cache, 1);
10142                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10143                         spin_lock(&info->unused_bgs_lock);
10144                         /* Should always be true but just in case. */
10145                         if (list_empty(&cache->bg_list)) {
10146                                 btrfs_get_block_group(cache);
10147                                 trace_btrfs_add_unused_block_group(cache);
10148                                 list_add_tail(&cache->bg_list,
10149                                               &info->unused_bgs);
10150                         }
10151                         spin_unlock(&info->unused_bgs_lock);
10152                 }
10153         }
10154
10155         list_for_each_entry_rcu(space_info, &info->space_info, list) {
10156                 if (!(get_alloc_profile(info, space_info->flags) &
10157                       (BTRFS_BLOCK_GROUP_RAID10 |
10158                        BTRFS_BLOCK_GROUP_RAID1 |
10159                        BTRFS_BLOCK_GROUP_RAID5 |
10160                        BTRFS_BLOCK_GROUP_RAID6 |
10161                        BTRFS_BLOCK_GROUP_DUP)))
10162                         continue;
10163                 /*
10164                  * avoid allocating from un-mirrored block group if there are
10165                  * mirrored block groups.
10166                  */
10167                 list_for_each_entry(cache,
10168                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10169                                 list)
10170                         inc_block_group_ro(cache, 1);
10171                 list_for_each_entry(cache,
10172                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10173                                 list)
10174                         inc_block_group_ro(cache, 1);
10175         }
10176
10177         btrfs_add_raid_kobjects(info);
10178         init_global_block_rsv(info);
10179         ret = 0;
10180 error:
10181         btrfs_free_path(path);
10182         return ret;
10183 }
10184
10185 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
10186 {
10187         struct btrfs_fs_info *fs_info = trans->fs_info;
10188         struct btrfs_block_group_cache *block_group, *tmp;
10189         struct btrfs_root *extent_root = fs_info->extent_root;
10190         struct btrfs_block_group_item item;
10191         struct btrfs_key key;
10192         int ret = 0;
10193         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10194
10195         trans->can_flush_pending_bgs = false;
10196         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
10197                 if (ret)
10198                         goto next;
10199
10200                 spin_lock(&block_group->lock);
10201                 memcpy(&item, &block_group->item, sizeof(item));
10202                 memcpy(&key, &block_group->key, sizeof(key));
10203                 spin_unlock(&block_group->lock);
10204
10205                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10206                                         sizeof(item));
10207                 if (ret)
10208                         btrfs_abort_transaction(trans, ret);
10209                 ret = btrfs_finish_chunk_alloc(trans, fs_info, key.objectid,
10210                                                key.offset);
10211                 if (ret)
10212                         btrfs_abort_transaction(trans, ret);
10213                 add_block_group_free_space(trans, block_group);
10214                 /* already aborted the transaction if it failed. */
10215 next:
10216                 list_del_init(&block_group->bg_list);
10217         }
10218         trans->can_flush_pending_bgs = can_flush_pending_bgs;
10219 }
10220
10221 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10222                            struct btrfs_fs_info *fs_info, u64 bytes_used,
10223                            u64 type, u64 chunk_offset, u64 size)
10224 {
10225         struct btrfs_block_group_cache *cache;
10226         int ret;
10227
10228         btrfs_set_log_full_commit(fs_info, trans);
10229
10230         cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
10231         if (!cache)
10232                 return -ENOMEM;
10233
10234         btrfs_set_block_group_used(&cache->item, bytes_used);
10235         btrfs_set_block_group_chunk_objectid(&cache->item,
10236                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID);
10237         btrfs_set_block_group_flags(&cache->item, type);
10238
10239         cache->flags = type;
10240         cache->last_byte_to_unpin = (u64)-1;
10241         cache->cached = BTRFS_CACHE_FINISHED;
10242         cache->needs_free_space = 1;
10243         ret = exclude_super_stripes(fs_info, cache);
10244         if (ret) {
10245                 /*
10246                  * We may have excluded something, so call this just in
10247                  * case.
10248                  */
10249                 free_excluded_extents(fs_info, cache);
10250                 btrfs_put_block_group(cache);
10251                 return ret;
10252         }
10253
10254         add_new_free_space(cache, chunk_offset, chunk_offset + size);
10255
10256         free_excluded_extents(fs_info, cache);
10257
10258 #ifdef CONFIG_BTRFS_DEBUG
10259         if (btrfs_should_fragment_free_space(cache)) {
10260                 u64 new_bytes_used = size - bytes_used;
10261
10262                 bytes_used += new_bytes_used >> 1;
10263                 fragment_free_space(cache);
10264         }
10265 #endif
10266         /*
10267          * Ensure the corresponding space_info object is created and
10268          * assigned to our block group. We want our bg to be added to the rbtree
10269          * with its ->space_info set.
10270          */
10271         cache->space_info = __find_space_info(fs_info, cache->flags);
10272         ASSERT(cache->space_info);
10273
10274         ret = btrfs_add_block_group_cache(fs_info, cache);
10275         if (ret) {
10276                 btrfs_remove_free_space_cache(cache);
10277                 btrfs_put_block_group(cache);
10278                 return ret;
10279         }
10280
10281         /*
10282          * Now that our block group has its ->space_info set and is inserted in
10283          * the rbtree, update the space info's counters.
10284          */
10285         trace_btrfs_add_block_group(fs_info, cache, 1);
10286         update_space_info(fs_info, cache->flags, size, bytes_used,
10287                                 cache->bytes_super, &cache->space_info);
10288         update_global_block_rsv(fs_info);
10289
10290         link_block_group(cache);
10291
10292         list_add_tail(&cache->bg_list, &trans->new_bgs);
10293
10294         set_avail_alloc_bits(fs_info, type);
10295         return 0;
10296 }
10297
10298 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10299 {
10300         u64 extra_flags = chunk_to_extended(flags) &
10301                                 BTRFS_EXTENDED_PROFILE_MASK;
10302
10303         write_seqlock(&fs_info->profiles_lock);
10304         if (flags & BTRFS_BLOCK_GROUP_DATA)
10305                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10306         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10307                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10308         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10309                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10310         write_sequnlock(&fs_info->profiles_lock);
10311 }
10312
10313 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10314                              struct btrfs_fs_info *fs_info, u64 group_start,
10315                              struct extent_map *em)
10316 {
10317         struct btrfs_root *root = fs_info->extent_root;
10318         struct btrfs_path *path;
10319         struct btrfs_block_group_cache *block_group;
10320         struct btrfs_free_cluster *cluster;
10321         struct btrfs_root *tree_root = fs_info->tree_root;
10322         struct btrfs_key key;
10323         struct inode *inode;
10324         struct kobject *kobj = NULL;
10325         int ret;
10326         int index;
10327         int factor;
10328         struct btrfs_caching_control *caching_ctl = NULL;
10329         bool remove_em;
10330
10331         block_group = btrfs_lookup_block_group(fs_info, group_start);
10332         BUG_ON(!block_group);
10333         BUG_ON(!block_group->ro);
10334
10335         trace_btrfs_remove_block_group(block_group);
10336         /*
10337          * Free the reserved super bytes from this block group before
10338          * remove it.
10339          */
10340         free_excluded_extents(fs_info, block_group);
10341         btrfs_free_ref_tree_range(fs_info, block_group->key.objectid,
10342                                   block_group->key.offset);
10343
10344         memcpy(&key, &block_group->key, sizeof(key));
10345         index = btrfs_bg_flags_to_raid_index(block_group->flags);
10346         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10347                                   BTRFS_BLOCK_GROUP_RAID1 |
10348                                   BTRFS_BLOCK_GROUP_RAID10))
10349                 factor = 2;
10350         else
10351                 factor = 1;
10352
10353         /* make sure this block group isn't part of an allocation cluster */
10354         cluster = &fs_info->data_alloc_cluster;
10355         spin_lock(&cluster->refill_lock);
10356         btrfs_return_cluster_to_free_space(block_group, cluster);
10357         spin_unlock(&cluster->refill_lock);
10358
10359         /*
10360          * make sure this block group isn't part of a metadata
10361          * allocation cluster
10362          */
10363         cluster = &fs_info->meta_alloc_cluster;
10364         spin_lock(&cluster->refill_lock);
10365         btrfs_return_cluster_to_free_space(block_group, cluster);
10366         spin_unlock(&cluster->refill_lock);
10367
10368         path = btrfs_alloc_path();
10369         if (!path) {
10370                 ret = -ENOMEM;
10371                 goto out;
10372         }
10373
10374         /*
10375          * get the inode first so any iput calls done for the io_list
10376          * aren't the final iput (no unlinks allowed now)
10377          */
10378         inode = lookup_free_space_inode(fs_info, block_group, path);
10379
10380         mutex_lock(&trans->transaction->cache_write_mutex);
10381         /*
10382          * make sure our free spache cache IO is done before remove the
10383          * free space inode
10384          */
10385         spin_lock(&trans->transaction->dirty_bgs_lock);
10386         if (!list_empty(&block_group->io_list)) {
10387                 list_del_init(&block_group->io_list);
10388
10389                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10390
10391                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10392                 btrfs_wait_cache_io(trans, block_group, path);
10393                 btrfs_put_block_group(block_group);
10394                 spin_lock(&trans->transaction->dirty_bgs_lock);
10395         }
10396
10397         if (!list_empty(&block_group->dirty_list)) {
10398                 list_del_init(&block_group->dirty_list);
10399                 btrfs_put_block_group(block_group);
10400         }
10401         spin_unlock(&trans->transaction->dirty_bgs_lock);
10402         mutex_unlock(&trans->transaction->cache_write_mutex);
10403
10404         if (!IS_ERR(inode)) {
10405                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10406                 if (ret) {
10407                         btrfs_add_delayed_iput(inode);
10408                         goto out;
10409                 }
10410                 clear_nlink(inode);
10411                 /* One for the block groups ref */
10412                 spin_lock(&block_group->lock);
10413                 if (block_group->iref) {
10414                         block_group->iref = 0;
10415                         block_group->inode = NULL;
10416                         spin_unlock(&block_group->lock);
10417                         iput(inode);
10418                 } else {
10419                         spin_unlock(&block_group->lock);
10420                 }
10421                 /* One for our lookup ref */
10422                 btrfs_add_delayed_iput(inode);
10423         }
10424
10425         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10426         key.offset = block_group->key.objectid;
10427         key.type = 0;
10428
10429         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10430         if (ret < 0)
10431                 goto out;
10432         if (ret > 0)
10433                 btrfs_release_path(path);
10434         if (ret == 0) {
10435                 ret = btrfs_del_item(trans, tree_root, path);
10436                 if (ret)
10437                         goto out;
10438                 btrfs_release_path(path);
10439         }
10440
10441         spin_lock(&fs_info->block_group_cache_lock);
10442         rb_erase(&block_group->cache_node,
10443                  &fs_info->block_group_cache_tree);
10444         RB_CLEAR_NODE(&block_group->cache_node);
10445
10446         if (fs_info->first_logical_byte == block_group->key.objectid)
10447                 fs_info->first_logical_byte = (u64)-1;
10448         spin_unlock(&fs_info->block_group_cache_lock);
10449
10450         down_write(&block_group->space_info->groups_sem);
10451         /*
10452          * we must use list_del_init so people can check to see if they
10453          * are still on the list after taking the semaphore
10454          */
10455         list_del_init(&block_group->list);
10456         if (list_empty(&block_group->space_info->block_groups[index])) {
10457                 kobj = block_group->space_info->block_group_kobjs[index];
10458                 block_group->space_info->block_group_kobjs[index] = NULL;
10459                 clear_avail_alloc_bits(fs_info, block_group->flags);
10460         }
10461         up_write(&block_group->space_info->groups_sem);
10462         if (kobj) {
10463                 kobject_del(kobj);
10464                 kobject_put(kobj);
10465         }
10466
10467         if (block_group->has_caching_ctl)
10468                 caching_ctl = get_caching_control(block_group);
10469         if (block_group->cached == BTRFS_CACHE_STARTED)
10470                 wait_block_group_cache_done(block_group);
10471         if (block_group->has_caching_ctl) {
10472                 down_write(&fs_info->commit_root_sem);
10473                 if (!caching_ctl) {
10474                         struct btrfs_caching_control *ctl;
10475
10476                         list_for_each_entry(ctl,
10477                                     &fs_info->caching_block_groups, list)
10478                                 if (ctl->block_group == block_group) {
10479                                         caching_ctl = ctl;
10480                                         refcount_inc(&caching_ctl->count);
10481                                         break;
10482                                 }
10483                 }
10484                 if (caching_ctl)
10485                         list_del_init(&caching_ctl->list);
10486                 up_write(&fs_info->commit_root_sem);
10487                 if (caching_ctl) {
10488                         /* Once for the caching bgs list and once for us. */
10489                         put_caching_control(caching_ctl);
10490                         put_caching_control(caching_ctl);
10491                 }
10492         }
10493
10494         spin_lock(&trans->transaction->dirty_bgs_lock);
10495         if (!list_empty(&block_group->dirty_list)) {
10496                 WARN_ON(1);
10497         }
10498         if (!list_empty(&block_group->io_list)) {
10499                 WARN_ON(1);
10500         }
10501         spin_unlock(&trans->transaction->dirty_bgs_lock);
10502         btrfs_remove_free_space_cache(block_group);
10503
10504         spin_lock(&block_group->space_info->lock);
10505         list_del_init(&block_group->ro_list);
10506
10507         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
10508                 WARN_ON(block_group->space_info->total_bytes
10509                         < block_group->key.offset);
10510                 WARN_ON(block_group->space_info->bytes_readonly
10511                         < block_group->key.offset);
10512                 WARN_ON(block_group->space_info->disk_total
10513                         < block_group->key.offset * factor);
10514         }
10515         block_group->space_info->total_bytes -= block_group->key.offset;
10516         block_group->space_info->bytes_readonly -= block_group->key.offset;
10517         block_group->space_info->disk_total -= block_group->key.offset * factor;
10518
10519         spin_unlock(&block_group->space_info->lock);
10520
10521         memcpy(&key, &block_group->key, sizeof(key));
10522
10523         mutex_lock(&fs_info->chunk_mutex);
10524         if (!list_empty(&em->list)) {
10525                 /* We're in the transaction->pending_chunks list. */
10526                 free_extent_map(em);
10527         }
10528         spin_lock(&block_group->lock);
10529         block_group->removed = 1;
10530         /*
10531          * At this point trimming can't start on this block group, because we
10532          * removed the block group from the tree fs_info->block_group_cache_tree
10533          * so no one can't find it anymore and even if someone already got this
10534          * block group before we removed it from the rbtree, they have already
10535          * incremented block_group->trimming - if they didn't, they won't find
10536          * any free space entries because we already removed them all when we
10537          * called btrfs_remove_free_space_cache().
10538          *
10539          * And we must not remove the extent map from the fs_info->mapping_tree
10540          * to prevent the same logical address range and physical device space
10541          * ranges from being reused for a new block group. This is because our
10542          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10543          * completely transactionless, so while it is trimming a range the
10544          * currently running transaction might finish and a new one start,
10545          * allowing for new block groups to be created that can reuse the same
10546          * physical device locations unless we take this special care.
10547          *
10548          * There may also be an implicit trim operation if the file system
10549          * is mounted with -odiscard. The same protections must remain
10550          * in place until the extents have been discarded completely when
10551          * the transaction commit has completed.
10552          */
10553         remove_em = (atomic_read(&block_group->trimming) == 0);
10554         /*
10555          * Make sure a trimmer task always sees the em in the pinned_chunks list
10556          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10557          * before checking block_group->removed).
10558          */
10559         if (!remove_em) {
10560                 /*
10561                  * Our em might be in trans->transaction->pending_chunks which
10562                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10563                  * and so is the fs_info->pinned_chunks list.
10564                  *
10565                  * So at this point we must be holding the chunk_mutex to avoid
10566                  * any races with chunk allocation (more specifically at
10567                  * volumes.c:contains_pending_extent()), to ensure it always
10568                  * sees the em, either in the pending_chunks list or in the
10569                  * pinned_chunks list.
10570                  */
10571                 list_move_tail(&em->list, &fs_info->pinned_chunks);
10572         }
10573         spin_unlock(&block_group->lock);
10574
10575         if (remove_em) {
10576                 struct extent_map_tree *em_tree;
10577
10578                 em_tree = &fs_info->mapping_tree.map_tree;
10579                 write_lock(&em_tree->lock);
10580                 /*
10581                  * The em might be in the pending_chunks list, so make sure the
10582                  * chunk mutex is locked, since remove_extent_mapping() will
10583                  * delete us from that list.
10584                  */
10585                 remove_extent_mapping(em_tree, em);
10586                 write_unlock(&em_tree->lock);
10587                 /* once for the tree */
10588                 free_extent_map(em);
10589         }
10590
10591         mutex_unlock(&fs_info->chunk_mutex);
10592
10593         ret = remove_block_group_free_space(trans, block_group);
10594         if (ret)
10595                 goto out;
10596
10597         btrfs_put_block_group(block_group);
10598         btrfs_put_block_group(block_group);
10599
10600         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10601         if (ret > 0)
10602                 ret = -EIO;
10603         if (ret < 0)
10604                 goto out;
10605
10606         ret = btrfs_del_item(trans, root, path);
10607 out:
10608         btrfs_free_path(path);
10609         return ret;
10610 }
10611
10612 struct btrfs_trans_handle *
10613 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10614                                      const u64 chunk_offset)
10615 {
10616         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10617         struct extent_map *em;
10618         struct map_lookup *map;
10619         unsigned int num_items;
10620
10621         read_lock(&em_tree->lock);
10622         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10623         read_unlock(&em_tree->lock);
10624         ASSERT(em && em->start == chunk_offset);
10625
10626         /*
10627          * We need to reserve 3 + N units from the metadata space info in order
10628          * to remove a block group (done at btrfs_remove_chunk() and at
10629          * btrfs_remove_block_group()), which are used for:
10630          *
10631          * 1 unit for adding the free space inode's orphan (located in the tree
10632          * of tree roots).
10633          * 1 unit for deleting the block group item (located in the extent
10634          * tree).
10635          * 1 unit for deleting the free space item (located in tree of tree
10636          * roots).
10637          * N units for deleting N device extent items corresponding to each
10638          * stripe (located in the device tree).
10639          *
10640          * In order to remove a block group we also need to reserve units in the
10641          * system space info in order to update the chunk tree (update one or
10642          * more device items and remove one chunk item), but this is done at
10643          * btrfs_remove_chunk() through a call to check_system_chunk().
10644          */
10645         map = em->map_lookup;
10646         num_items = 3 + map->num_stripes;
10647         free_extent_map(em);
10648
10649         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10650                                                            num_items, 1);
10651 }
10652
10653 /*
10654  * Process the unused_bgs list and remove any that don't have any allocated
10655  * space inside of them.
10656  */
10657 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10658 {
10659         struct btrfs_block_group_cache *block_group;
10660         struct btrfs_space_info *space_info;
10661         struct btrfs_trans_handle *trans;
10662         int ret = 0;
10663
10664         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10665                 return;
10666
10667         spin_lock(&fs_info->unused_bgs_lock);
10668         while (!list_empty(&fs_info->unused_bgs)) {
10669                 u64 start, end;
10670                 int trimming;
10671
10672                 block_group = list_first_entry(&fs_info->unused_bgs,
10673                                                struct btrfs_block_group_cache,
10674                                                bg_list);
10675                 list_del_init(&block_group->bg_list);
10676
10677                 space_info = block_group->space_info;
10678
10679                 if (ret || btrfs_mixed_space_info(space_info)) {
10680                         btrfs_put_block_group(block_group);
10681                         continue;
10682                 }
10683                 spin_unlock(&fs_info->unused_bgs_lock);
10684
10685                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10686
10687                 /* Don't want to race with allocators so take the groups_sem */
10688                 down_write(&space_info->groups_sem);
10689                 spin_lock(&block_group->lock);
10690                 if (block_group->reserved ||
10691                     btrfs_block_group_used(&block_group->item) ||
10692                     block_group->ro ||
10693                     list_is_singular(&block_group->list)) {
10694                         /*
10695                          * We want to bail if we made new allocations or have
10696                          * outstanding allocations in this block group.  We do
10697                          * the ro check in case balance is currently acting on
10698                          * this block group.
10699                          */
10700                         trace_btrfs_skip_unused_block_group(block_group);
10701                         spin_unlock(&block_group->lock);
10702                         up_write(&space_info->groups_sem);
10703                         goto next;
10704                 }
10705                 spin_unlock(&block_group->lock);
10706
10707                 /* We don't want to force the issue, only flip if it's ok. */
10708                 ret = inc_block_group_ro(block_group, 0);
10709                 up_write(&space_info->groups_sem);
10710                 if (ret < 0) {
10711                         ret = 0;
10712                         goto next;
10713                 }
10714
10715                 /*
10716                  * Want to do this before we do anything else so we can recover
10717                  * properly if we fail to join the transaction.
10718                  */
10719                 trans = btrfs_start_trans_remove_block_group(fs_info,
10720                                                      block_group->key.objectid);
10721                 if (IS_ERR(trans)) {
10722                         btrfs_dec_block_group_ro(block_group);
10723                         ret = PTR_ERR(trans);
10724                         goto next;
10725                 }
10726
10727                 /*
10728                  * We could have pending pinned extents for this block group,
10729                  * just delete them, we don't care about them anymore.
10730                  */
10731                 start = block_group->key.objectid;
10732                 end = start + block_group->key.offset - 1;
10733                 /*
10734                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10735                  * btrfs_finish_extent_commit(). If we are at transaction N,
10736                  * another task might be running finish_extent_commit() for the
10737                  * previous transaction N - 1, and have seen a range belonging
10738                  * to the block group in freed_extents[] before we were able to
10739                  * clear the whole block group range from freed_extents[]. This
10740                  * means that task can lookup for the block group after we
10741                  * unpinned it from freed_extents[] and removed it, leading to
10742                  * a BUG_ON() at btrfs_unpin_extent_range().
10743                  */
10744                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10745                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10746                                   EXTENT_DIRTY);
10747                 if (ret) {
10748                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10749                         btrfs_dec_block_group_ro(block_group);
10750                         goto end_trans;
10751                 }
10752                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10753                                   EXTENT_DIRTY);
10754                 if (ret) {
10755                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10756                         btrfs_dec_block_group_ro(block_group);
10757                         goto end_trans;
10758                 }
10759                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10760
10761                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10762                 spin_lock(&space_info->lock);
10763                 spin_lock(&block_group->lock);
10764
10765                 space_info->bytes_pinned -= block_group->pinned;
10766                 space_info->bytes_readonly += block_group->pinned;
10767                 percpu_counter_add(&space_info->total_bytes_pinned,
10768                                    -block_group->pinned);
10769                 block_group->pinned = 0;
10770
10771                 spin_unlock(&block_group->lock);
10772                 spin_unlock(&space_info->lock);
10773
10774                 /* DISCARD can flip during remount */
10775                 trimming = btrfs_test_opt(fs_info, DISCARD);
10776
10777                 /* Implicit trim during transaction commit. */
10778                 if (trimming)
10779                         btrfs_get_block_group_trimming(block_group);
10780
10781                 /*
10782                  * Btrfs_remove_chunk will abort the transaction if things go
10783                  * horribly wrong.
10784                  */
10785                 ret = btrfs_remove_chunk(trans, fs_info,
10786                                          block_group->key.objectid);
10787
10788                 if (ret) {
10789                         if (trimming)
10790                                 btrfs_put_block_group_trimming(block_group);
10791                         goto end_trans;
10792                 }
10793
10794                 /*
10795                  * If we're not mounted with -odiscard, we can just forget
10796                  * about this block group. Otherwise we'll need to wait
10797                  * until transaction commit to do the actual discard.
10798                  */
10799                 if (trimming) {
10800                         spin_lock(&fs_info->unused_bgs_lock);
10801                         /*
10802                          * A concurrent scrub might have added us to the list
10803                          * fs_info->unused_bgs, so use a list_move operation
10804                          * to add the block group to the deleted_bgs list.
10805                          */
10806                         list_move(&block_group->bg_list,
10807                                   &trans->transaction->deleted_bgs);
10808                         spin_unlock(&fs_info->unused_bgs_lock);
10809                         btrfs_get_block_group(block_group);
10810                 }
10811 end_trans:
10812                 btrfs_end_transaction(trans);
10813 next:
10814                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
10815                 btrfs_put_block_group(block_group);
10816                 spin_lock(&fs_info->unused_bgs_lock);
10817         }
10818         spin_unlock(&fs_info->unused_bgs_lock);
10819 }
10820
10821 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10822 {
10823         struct btrfs_super_block *disk_super;
10824         u64 features;
10825         u64 flags;
10826         int mixed = 0;
10827         int ret;
10828
10829         disk_super = fs_info->super_copy;
10830         if (!btrfs_super_root(disk_super))
10831                 return -EINVAL;
10832
10833         features = btrfs_super_incompat_flags(disk_super);
10834         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10835                 mixed = 1;
10836
10837         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10838         ret = create_space_info(fs_info, flags);
10839         if (ret)
10840                 goto out;
10841
10842         if (mixed) {
10843                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10844                 ret = create_space_info(fs_info, flags);
10845         } else {
10846                 flags = BTRFS_BLOCK_GROUP_METADATA;
10847                 ret = create_space_info(fs_info, flags);
10848                 if (ret)
10849                         goto out;
10850
10851                 flags = BTRFS_BLOCK_GROUP_DATA;
10852                 ret = create_space_info(fs_info, flags);
10853         }
10854 out:
10855         return ret;
10856 }
10857
10858 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
10859                                    u64 start, u64 end)
10860 {
10861         return unpin_extent_range(fs_info, start, end, false);
10862 }
10863
10864 /*
10865  * It used to be that old block groups would be left around forever.
10866  * Iterating over them would be enough to trim unused space.  Since we
10867  * now automatically remove them, we also need to iterate over unallocated
10868  * space.
10869  *
10870  * We don't want a transaction for this since the discard may take a
10871  * substantial amount of time.  We don't require that a transaction be
10872  * running, but we do need to take a running transaction into account
10873  * to ensure that we're not discarding chunks that were released in
10874  * the current transaction.
10875  *
10876  * Holding the chunks lock will prevent other threads from allocating
10877  * or releasing chunks, but it won't prevent a running transaction
10878  * from committing and releasing the memory that the pending chunks
10879  * list head uses.  For that, we need to take a reference to the
10880  * transaction.
10881  */
10882 static int btrfs_trim_free_extents(struct btrfs_device *device,
10883                                    u64 minlen, u64 *trimmed)
10884 {
10885         u64 start = 0, len = 0;
10886         int ret;
10887
10888         *trimmed = 0;
10889
10890         /* Not writeable = nothing to do. */
10891         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
10892                 return 0;
10893
10894         /* No free space = nothing to do. */
10895         if (device->total_bytes <= device->bytes_used)
10896                 return 0;
10897
10898         ret = 0;
10899
10900         while (1) {
10901                 struct btrfs_fs_info *fs_info = device->fs_info;
10902                 struct btrfs_transaction *trans;
10903                 u64 bytes;
10904
10905                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10906                 if (ret)
10907                         return ret;
10908
10909                 down_read(&fs_info->commit_root_sem);
10910
10911                 spin_lock(&fs_info->trans_lock);
10912                 trans = fs_info->running_transaction;
10913                 if (trans)
10914                         refcount_inc(&trans->use_count);
10915                 spin_unlock(&fs_info->trans_lock);
10916
10917                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10918                                                  &start, &len);
10919                 if (trans)
10920                         btrfs_put_transaction(trans);
10921
10922                 if (ret) {
10923                         up_read(&fs_info->commit_root_sem);
10924                         mutex_unlock(&fs_info->chunk_mutex);
10925                         if (ret == -ENOSPC)
10926                                 ret = 0;
10927                         break;
10928                 }
10929
10930                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10931                 up_read(&fs_info->commit_root_sem);
10932                 mutex_unlock(&fs_info->chunk_mutex);
10933
10934                 if (ret)
10935                         break;
10936
10937                 start += len;
10938                 *trimmed += bytes;
10939
10940                 if (fatal_signal_pending(current)) {
10941                         ret = -ERESTARTSYS;
10942                         break;
10943                 }
10944
10945                 cond_resched();
10946         }
10947
10948         return ret;
10949 }
10950
10951 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
10952 {
10953         struct btrfs_block_group_cache *cache = NULL;
10954         struct btrfs_device *device;
10955         struct list_head *devices;
10956         u64 group_trimmed;
10957         u64 start;
10958         u64 end;
10959         u64 trimmed = 0;
10960         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10961         int ret = 0;
10962
10963         /*
10964          * try to trim all FS space, our block group may start from non-zero.
10965          */
10966         if (range->len == total_bytes)
10967                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10968         else
10969                 cache = btrfs_lookup_block_group(fs_info, range->start);
10970
10971         while (cache) {
10972                 if (cache->key.objectid >= (range->start + range->len)) {
10973                         btrfs_put_block_group(cache);
10974                         break;
10975                 }
10976
10977                 start = max(range->start, cache->key.objectid);
10978                 end = min(range->start + range->len,
10979                                 cache->key.objectid + cache->key.offset);
10980
10981                 if (end - start >= range->minlen) {
10982                         if (!block_group_cache_done(cache)) {
10983                                 ret = cache_block_group(cache, 0);
10984                                 if (ret) {
10985                                         btrfs_put_block_group(cache);
10986                                         break;
10987                                 }
10988                                 ret = wait_block_group_cache_done(cache);
10989                                 if (ret) {
10990                                         btrfs_put_block_group(cache);
10991                                         break;
10992                                 }
10993                         }
10994                         ret = btrfs_trim_block_group(cache,
10995                                                      &group_trimmed,
10996                                                      start,
10997                                                      end,
10998                                                      range->minlen);
10999
11000                         trimmed += group_trimmed;
11001                         if (ret) {
11002                                 btrfs_put_block_group(cache);
11003                                 break;
11004                         }
11005                 }
11006
11007                 cache = next_block_group(fs_info, cache);
11008         }
11009
11010         mutex_lock(&fs_info->fs_devices->device_list_mutex);
11011         devices = &fs_info->fs_devices->alloc_list;
11012         list_for_each_entry(device, devices, dev_alloc_list) {
11013                 ret = btrfs_trim_free_extents(device, range->minlen,
11014                                               &group_trimmed);
11015                 if (ret)
11016                         break;
11017
11018                 trimmed += group_trimmed;
11019         }
11020         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
11021
11022         range->len = trimmed;
11023         return ret;
11024 }
11025
11026 /*
11027  * btrfs_{start,end}_write_no_snapshotting() are similar to
11028  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11029  * data into the page cache through nocow before the subvolume is snapshoted,
11030  * but flush the data into disk after the snapshot creation, or to prevent
11031  * operations while snapshotting is ongoing and that cause the snapshot to be
11032  * inconsistent (writes followed by expanding truncates for example).
11033  */
11034 void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
11035 {
11036         percpu_counter_dec(&root->subv_writers->counter);
11037         cond_wake_up(&root->subv_writers->wait);
11038 }
11039
11040 int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
11041 {
11042         if (atomic_read(&root->will_be_snapshotted))
11043                 return 0;
11044
11045         percpu_counter_inc(&root->subv_writers->counter);
11046         /*
11047          * Make sure counter is updated before we check for snapshot creation.
11048          */
11049         smp_mb();
11050         if (atomic_read(&root->will_be_snapshotted)) {
11051                 btrfs_end_write_no_snapshotting(root);
11052                 return 0;
11053         }
11054         return 1;
11055 }
11056
11057 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11058 {
11059         while (true) {
11060                 int ret;
11061
11062                 ret = btrfs_start_write_no_snapshotting(root);
11063                 if (ret)
11064                         break;
11065                 wait_var_event(&root->will_be_snapshotted,
11066                                !atomic_read(&root->will_be_snapshotted));
11067         }
11068 }