fs/btrfs/block-group.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include "misc.h"
   4 #include "ctree.h"
   5 #include "block-group.h"
   6 #include "space-info.h"
   7 #include "disk-io.h"
   8 #include "free-space-cache.h"
   9 #include "free-space-tree.h"
  10 #include "volumes.h"
  11 #include "transaction.h"
  12 #include "ref-verify.h"
  13 #include "sysfs.h"
  14 #include "tree-log.h"
  15 #include "delalloc-space.h"
  16 #include "discard.h"
  17 #include "raid56.h"
  18
  19 /*
  20  * Return target flags in extended format or 0 if restripe for this chunk_type
  21  * is not in progress
  22  *
  23  * Should be called with balance_lock held
  24  */
  25 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
  26 {
  27         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
  28         u64 target = 0;
  29
  30         if (!bctl)
  31                 return 0;
  32
  33         if (flags & BTRFS_BLOCK_GROUP_DATA &&
  34             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
  35                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
  36         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
  37                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
  38                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
  39         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
  40                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
  41                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
  42         }
  43
  44         return target;
  45 }
  46
  47 /*
  48  * @flags: available profiles in extended format (see ctree.h)
  49  *
  50  * Return reduced profile in chunk format.  If profile changing is in progress
  51  * (either running or paused) picks the target profile (if it's already
  52  * available), otherwise falls back to plain reducing.
  53  */
  54 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
  55 {
  56         u64 num_devices = fs_info->fs_devices->rw_devices;
  57         u64 target;
  58         u64 raid_type;
  59         u64 allowed = 0;
  60
  61         /*
  62          * See if restripe for this chunk_type is in progress, if so try to
  63          * reduce to the target profile
  64          */
  65         spin_lock(&fs_info->balance_lock);
  66         target = get_restripe_target(fs_info, flags);
  67         if (target) {
  68                 spin_unlock(&fs_info->balance_lock);
  69                 return extended_to_chunk(target);
  70         }
  71         spin_unlock(&fs_info->balance_lock);
  72
  73         /* First, mask out the RAID levels which aren't possible */
  74         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
  75                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
  76                         allowed |= btrfs_raid_array[raid_type].bg_flag;
  77         }
  78         allowed &= flags;
  79
  80         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
  81                 allowed = BTRFS_BLOCK_GROUP_RAID6;
  82         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
  83                 allowed = BTRFS_BLOCK_GROUP_RAID5;
  84         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
  85                 allowed = BTRFS_BLOCK_GROUP_RAID10;
  86         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
  87                 allowed = BTRFS_BLOCK_GROUP_RAID1;
  88         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
  89                 allowed = BTRFS_BLOCK_GROUP_RAID0;
  90
  91         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
  92
  93         return extended_to_chunk(flags | allowed);
  94 }
  95
  96 u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
  97 {
  98         unsigned seq;
  99         u64 flags;
 100
 101         do {
 102                 flags = orig_flags;
 103                 seq = read_seqbegin(&fs_info->profiles_lock);
 104
 105                 if (flags & BTRFS_BLOCK_GROUP_DATA)
 106                         flags |= fs_info->avail_data_alloc_bits;
 107                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
 108                         flags |= fs_info->avail_system_alloc_bits;
 109                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
 110                         flags |= fs_info->avail_metadata_alloc_bits;
 111         } while (read_seqretry(&fs_info->profiles_lock, seq));
 112
 113         return btrfs_reduce_alloc_profile(fs_info, flags);
 114 }
 115
 116 void btrfs_get_block_group(struct btrfs_block_group *cache)
 117 {
 118         refcount_inc(&cache->refs);
 119 }
 120
 121 void btrfs_put_block_group(struct btrfs_block_group *cache)
 122 {
 123         if (refcount_dec_and_test(&cache->refs)) {
 124                 WARN_ON(cache->pinned > 0);
 125                 WARN_ON(cache->reserved > 0);
 126
 127                 /*
 128                  * A block_group shouldn't be on the discard_list anymore.
 129                  * Remove the block_group from the discard_list to prevent us
 130                  * from causing a panic due to NULL pointer dereference.
 131                  */
 132                 if (WARN_ON(!list_empty(&cache->discard_list)))
 133                         btrfs_discard_cancel_work(&cache->fs_info->discard_ctl,
 134                                                   cache);
 135
 136                 /*
 137                  * If not empty, someone is still holding mutex of
 138                  * full_stripe_lock, which can only be released by caller.
 139                  * And it will definitely cause use-after-free when caller
 140                  * tries to release full stripe lock.
 141                  *
 142                  * No better way to resolve, but only to warn.
 143                  */
 144                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 145                 kfree(cache->free_space_ctl);
 146                 kfree(cache);
 147         }
 148 }
 149
 150 /*
 151  * This adds the block group to the fs_info rb tree for the block group cache
 152  */
 153 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 154                                        struct btrfs_block_group *block_group)
 155 {
 156         struct rb_node **p;
 157         struct rb_node *parent = NULL;
 158         struct btrfs_block_group *cache;
 159
 160         ASSERT(block_group->length != 0);
 161
 162         spin_lock(&info->block_group_cache_lock);
 163         p = &info->block_group_cache_tree.rb_node;
 164
 165         while (*p) {
 166                 parent = *p;
 167                 cache = rb_entry(parent, struct btrfs_block_group, cache_node);
 168                 if (block_group->start < cache->start) {
 169                         p = &(*p)->rb_left;
 170                 } else if (block_group->start > cache->start) {
 171                         p = &(*p)->rb_right;
 172                 } else {
 173                         spin_unlock(&info->block_group_cache_lock);
 174                         return -EEXIST;
 175                 }
 176         }
 177
 178         rb_link_node(&block_group->cache_node, parent, p);
 179         rb_insert_color(&block_group->cache_node,
 180                         &info->block_group_cache_tree);
 181
 182         if (info->first_logical_byte > block_group->start)
 183                 info->first_logical_byte = block_group->start;
 184
 185         spin_unlock(&info->block_group_cache_lock);
 186
 187         return 0;
 188 }
 189
 190 /*
 191  * This will return the block group at or after bytenr if contains is 0, else
 192  * it will return the block group that contains the bytenr
 193  */
 194 static struct btrfs_block_group *block_group_cache_tree_search(
 195                 struct btrfs_fs_info *info, u64 bytenr, int contains)
 196 {
 197         struct btrfs_block_group *cache, *ret = NULL;
 198         struct rb_node *n;
 199         u64 end, start;
 200
 201         spin_lock(&info->block_group_cache_lock);
 202         n = info->block_group_cache_tree.rb_node;
 203
 204         while (n) {
 205                 cache = rb_entry(n, struct btrfs_block_group, cache_node);
 206                 end = cache->start + cache->length - 1;
 207                 start = cache->start;
 208
 209                 if (bytenr < start) {
 210                         if (!contains && (!ret || start < ret->start))
 211                                 ret = cache;
 212                         n = n->rb_left;
 213                 } else if (bytenr > start) {
 214                         if (contains && bytenr <= end) {
 215                                 ret = cache;
 216                                 break;
 217                         }
 218                         n = n->rb_right;
 219                 } else {
 220                         ret = cache;
 221                         break;
 222                 }
 223         }
 224         if (ret) {
 225                 btrfs_get_block_group(ret);
 226                 if (bytenr == 0 && info->first_logical_byte > ret->start)
 227                         info->first_logical_byte = ret->start;
 228         }
 229         spin_unlock(&info->block_group_cache_lock);
 230
 231         return ret;
 232 }
 233
 234 /*
 235  * Return the block group that starts at or after bytenr
 236  */
 237 struct btrfs_block_group *btrfs_lookup_first_block_group(
 238                 struct btrfs_fs_info *info, u64 bytenr)
 239 {
 240         return block_group_cache_tree_search(info, bytenr, 0);
 241 }
 242
 243 /*
 244  * Return the block group that contains the given bytenr
 245  */
 246 struct btrfs_block_group *btrfs_lookup_block_group(
 247                 struct btrfs_fs_info *info, u64 bytenr)
 248 {
 249         return block_group_cache_tree_search(info, bytenr, 1);
 250 }
 251
 252 struct btrfs_block_group *btrfs_next_block_group(
 253                 struct btrfs_block_group *cache)
 254 {
 255         struct btrfs_fs_info *fs_info = cache->fs_info;
 256         struct rb_node *node;
 257
 258         spin_lock(&fs_info->block_group_cache_lock);
 259
 260         /* If our block group was removed, we need a full search. */
 261         if (RB_EMPTY_NODE(&cache->cache_node)) {
 262                 const u64 next_bytenr = cache->start + cache->length;
 263
 264                 spin_unlock(&fs_info->block_group_cache_lock);
 265                 btrfs_put_block_group(cache);
 266                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
 267         }
 268         node = rb_next(&cache->cache_node);
 269         btrfs_put_block_group(cache);
 270         if (node) {
 271                 cache = rb_entry(node, struct btrfs_block_group, cache_node);
 272                 btrfs_get_block_group(cache);
 273         } else
 274                 cache = NULL;
 275         spin_unlock(&fs_info->block_group_cache_lock);
 276         return cache;
 277 }
 278
 279 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
 280 {
 281         struct btrfs_block_group *bg;
 282         bool ret = true;
 283
 284         bg = btrfs_lookup_block_group(fs_info, bytenr);
 285         if (!bg)
 286                 return false;
 287
 288         spin_lock(&bg->lock);
 289         if (bg->ro)
 290                 ret = false;
 291         else
 292                 atomic_inc(&bg->nocow_writers);
 293         spin_unlock(&bg->lock);
 294
 295         /* No put on block group, done by btrfs_dec_nocow_writers */
 296         if (!ret)
 297                 btrfs_put_block_group(bg);
 298
 299         return ret;
 300 }
 301
 302 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
 303 {
 304         struct btrfs_block_group *bg;
 305
 306         bg = btrfs_lookup_block_group(fs_info, bytenr);
 307         ASSERT(bg);
 308         if (atomic_dec_and_test(&bg->nocow_writers))
 309                 wake_up_var(&bg->nocow_writers);
 310         /*
 311          * Once for our lookup and once for the lookup done by a previous call
 312          * to btrfs_inc_nocow_writers()
 313          */
 314         btrfs_put_block_group(bg);
 315         btrfs_put_block_group(bg);
 316 }
 317
 318 void btrfs_wait_nocow_writers(struct btrfs_block_group *bg)
 319 {
 320         wait_var_event(&bg->nocow_writers, !atomic_read(&bg->nocow_writers));
 321 }
 322
 323 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
 324                                         const u64 start)
 325 {
 326         struct btrfs_block_group *bg;
 327
 328         bg = btrfs_lookup_block_group(fs_info, start);
 329         ASSERT(bg);
 330         if (atomic_dec_and_test(&bg->reservations))
 331                 wake_up_var(&bg->reservations);
 332         btrfs_put_block_group(bg);
 333 }
 334
 335 void btrfs_wait_block_group_reservations(struct btrfs_block_group *bg)
 336 {
 337         struct btrfs_space_info *space_info = bg->space_info;
 338
 339         ASSERT(bg->ro);
 340
 341         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
 342                 return;
 343
 344         /*
 345          * Our block group is read only but before we set it to read only,
 346          * some task might have had allocated an extent from it already, but it
 347          * has not yet created a respective ordered extent (and added it to a
 348          * root's list of ordered extents).
 349          * Therefore wait for any task currently allocating extents, since the
 350          * block group's reservations counter is incremented while a read lock
 351          * on the groups' semaphore is held and decremented after releasing
 352          * the read access on that semaphore and creating the ordered extent.
 353          */
 354         down_write(&space_info->groups_sem);
 355         up_write(&space_info->groups_sem);
 356
 357         wait_var_event(&bg->reservations, !atomic_read(&bg->reservations));
 358 }
 359
 360 struct btrfs_caching_control *btrfs_get_caching_control(
 361                 struct btrfs_block_group *cache)
 362 {
 363         struct btrfs_caching_control *ctl;
 364
 365         spin_lock(&cache->lock);
 366         if (!cache->caching_ctl) {
 367                 spin_unlock(&cache->lock);
 368                 return NULL;
 369         }
 370
 371         ctl = cache->caching_ctl;
 372         refcount_inc(&ctl->count);
 373         spin_unlock(&cache->lock);
 374         return ctl;
 375 }
 376
 377 void btrfs_put_caching_control(struct btrfs_caching_control *ctl)
 378 {
 379         if (refcount_dec_and_test(&ctl->count))
 380                 kfree(ctl);
 381 }
 382
 383 /*
 384  * When we wait for progress in the block group caching, its because our
 385  * allocation attempt failed at least once.  So, we must sleep and let some
 386  * progress happen before we try again.
 387  *
 388  * This function will sleep at least once waiting for new free space to show
 389  * up, and then it will check the block group free space numbers for our min
 390  * num_bytes.  Another option is to have it go ahead and look in the rbtree for
 391  * a free extent of a given size, but this is a good start.
 392  *
 393  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
 394  * any of the information in this block group.
 395  */
 396 void btrfs_wait_block_group_cache_progress(struct btrfs_block_group *cache,
 397                                            u64 num_bytes)
 398 {
 399         struct btrfs_caching_control *caching_ctl;
 400
 401         caching_ctl = btrfs_get_caching_control(cache);
 402         if (!caching_ctl)
 403                 return;
 404
 405         wait_event(caching_ctl->wait, btrfs_block_group_done(cache) ||
 406                    (cache->free_space_ctl->free_space >= num_bytes));
 407
 408         btrfs_put_caching_control(caching_ctl);
 409 }
 410
 411 int btrfs_wait_block_group_cache_done(struct btrfs_block_group *cache)
 412 {
 413         struct btrfs_caching_control *caching_ctl;
 414         int ret = 0;
 415
 416         caching_ctl = btrfs_get_caching_control(cache);
 417         if (!caching_ctl)
 418                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
 419
 420         wait_event(caching_ctl->wait, btrfs_block_group_done(cache));
 421         if (cache->cached == BTRFS_CACHE_ERROR)
 422                 ret = -EIO;
 423         btrfs_put_caching_control(caching_ctl);
 424         return ret;
 425 }
 426
 427 #ifdef CONFIG_BTRFS_DEBUG
 428 static void fragment_free_space(struct btrfs_block_group *block_group)
 429 {
 430         struct btrfs_fs_info *fs_info = block_group->fs_info;
 431         u64 start = block_group->start;
 432         u64 len = block_group->length;
 433         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 434                 fs_info->nodesize : fs_info->sectorsize;
 435         u64 step = chunk << 1;
 436
 437         while (len > chunk) {
 438                 btrfs_remove_free_space(block_group, start, chunk);
 439                 start += step;
 440                 if (len < step)
 441                         len = 0;
 442                 else
 443                         len -= step;
 444         }
 445 }
 446 #endif
 447
 448 /*
 449  * This is only called by btrfs_cache_block_group, since we could have freed
 450  * extents we need to check the pinned_extents for any extents that can't be
 451  * used yet since their free space will be released as soon as the transaction
 452  * commits.
 453  */
 454 u64 add_new_free_space(struct btrfs_block_group *block_group, u64 start, u64 end)
 455 {
 456         struct btrfs_fs_info *info = block_group->fs_info;
 457         u64 extent_start, extent_end, size, total_added = 0;
 458         int ret;
 459
 460         while (start < end) {
 461                 ret = find_first_extent_bit(&info->excluded_extents, start,
 462                                             &extent_start, &extent_end,
 463                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 464                                             NULL);
 465                 if (ret)
 466                         break;
 467
 468                 if (extent_start <= start) {
 469                         start = extent_end + 1;
 470                 } else if (extent_start > start && extent_start < end) {
 471                         size = extent_start - start;
 472                         total_added += size;
 473                         ret = btrfs_add_free_space_async_trimmed(block_group,
 474                                                                  start, size);
 475                         BUG_ON(ret); /* -ENOMEM or logic error */
 476                         start = extent_end + 1;
 477                 } else {
 478                         break;
 479                 }
 480         }
 481
 482         if (start < end) {
 483                 size = end - start;
 484                 total_added += size;
 485                 ret = btrfs_add_free_space_async_trimmed(block_group, start,
 486                                                          size);
 487                 BUG_ON(ret); /* -ENOMEM or logic error */
 488         }
 489
 490         return total_added;
 491 }
 492
 493 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 494 {
 495         struct btrfs_block_group *block_group = caching_ctl->block_group;
 496         struct btrfs_fs_info *fs_info = block_group->fs_info;
 497         struct btrfs_root *extent_root = fs_info->extent_root;
 498         struct btrfs_path *path;
 499         struct extent_buffer *leaf;
 500         struct btrfs_key key;
 501         u64 total_found = 0;
 502         u64 last = 0;
 503         u32 nritems;
 504         int ret;
 505         bool wakeup = true;
 506
 507         path = btrfs_alloc_path();
 508         if (!path)
 509                 return -ENOMEM;
 510
 511         last = max_t(u64, block_group->start, BTRFS_SUPER_INFO_OFFSET);
 512
 513 #ifdef CONFIG_BTRFS_DEBUG
 514         /*
 515          * If we're fragmenting we don't want to make anybody think we can
 516          * allocate from this block group until we've had a chance to fragment
 517          * the free space.
 518          */
 519         if (btrfs_should_fragment_free_space(block_group))
 520                 wakeup = false;
 521 #endif
 522         /*
 523          * We don't want to deadlock with somebody trying to allocate a new
 524          * extent for the extent root while also trying to search the extent
 525          * root to add free space.  So we skip locking and search the commit
 526          * root, since its read-only
 527          */
 528         path->skip_locking = 1;
 529         path->search_commit_root = 1;
 530         path->reada = READA_FORWARD;
 531
 532         key.objectid = last;
 533         key.offset = 0;
 534         key.type = BTRFS_EXTENT_ITEM_KEY;
 535
 536 next:
 537         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 538         if (ret < 0)
 539                 goto out;
 540
 541         leaf = path->nodes[0];
 542         nritems = btrfs_header_nritems(leaf);
 543
 544         while (1) {
 545                 if (btrfs_fs_closing(fs_info) > 1) {
 546                         last = (u64)-1;
 547                         break;
 548                 }
 549
 550                 if (path->slots[0] < nritems) {
 551                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 552                 } else {
 553                         ret = btrfs_find_next_key(extent_root, path, &key, 0, 0);
 554                         if (ret)
 555                                 break;
 556
 557                         if (need_resched() ||
 558                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 559                                 if (wakeup)
 560                                         caching_ctl->progress = last;
 561                                 btrfs_release_path(path);
 562                                 up_read(&fs_info->commit_root_sem);
 563                                 mutex_unlock(&caching_ctl->mutex);
 564                                 cond_resched();
 565                                 mutex_lock(&caching_ctl->mutex);
 566                                 down_read(&fs_info->commit_root_sem);
 567                                 goto next;
 568                         }
 569
 570                         ret = btrfs_next_leaf(extent_root, path);
 571                         if (ret < 0)
 572                                 goto out;
 573                         if (ret)
 574                                 break;
 575                         leaf = path->nodes[0];
 576                         nritems = btrfs_header_nritems(leaf);
 577                         continue;
 578                 }
 579
 580                 if (key.objectid < last) {
 581                         key.objectid = last;
 582                         key.offset = 0;
 583                         key.type = BTRFS_EXTENT_ITEM_KEY;
 584
 585                         if (wakeup)
 586                                 caching_ctl->progress = last;
 587                         btrfs_release_path(path);
 588                         goto next;
 589                 }
 590
 591                 if (key.objectid < block_group->start) {
 592                         path->slots[0]++;
 593                         continue;
 594                 }
 595
 596                 if (key.objectid >= block_group->start + block_group->length)
 597                         break;
 598
 599                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 600                     key.type == BTRFS_METADATA_ITEM_KEY) {
 601                         total_found += add_new_free_space(block_group, last,
 602                                                           key.objectid);
 603                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 604                                 last = key.objectid +
 605                                         fs_info->nodesize;
 606                         else
 607                                 last = key.objectid + key.offset;
 608
 609                         if (total_found > CACHING_CTL_WAKE_UP) {
 610                                 total_found = 0;
 611                                 if (wakeup)
 612                                         wake_up(&caching_ctl->wait);
 613                         }
 614                 }
 615                 path->slots[0]++;
 616         }
 617         ret = 0;
 618
 619         total_found += add_new_free_space(block_group, last,
 620                                 block_group->start + block_group->length);
 621         caching_ctl->progress = (u64)-1;
 622
 623 out:
 624         btrfs_free_path(path);
 625         return ret;
 626 }
 627
 628 static noinline void caching_thread(struct btrfs_work *work)
 629 {
 630         struct btrfs_block_group *block_group;
 631         struct btrfs_fs_info *fs_info;
 632         struct btrfs_caching_control *caching_ctl;
 633         int ret;
 634
 635         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 636         block_group = caching_ctl->block_group;
 637         fs_info = block_group->fs_info;
 638
 639         mutex_lock(&caching_ctl->mutex);
 640         down_read(&fs_info->commit_root_sem);
 641
 642         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 643                 ret = load_free_space_tree(caching_ctl);
 644         else
 645                 ret = load_extent_tree_free(caching_ctl);
 646
 647         spin_lock(&block_group->lock);
 648         block_group->caching_ctl = NULL;
 649         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 650         spin_unlock(&block_group->lock);
 651
 652 #ifdef CONFIG_BTRFS_DEBUG
 653         if (btrfs_should_fragment_free_space(block_group)) {
 654                 u64 bytes_used;
 655
 656                 spin_lock(&block_group->space_info->lock);
 657                 spin_lock(&block_group->lock);
 658                 bytes_used = block_group->length - block_group->used;
 659                 block_group->space_info->bytes_used += bytes_used >> 1;
 660                 spin_unlock(&block_group->lock);
 661                 spin_unlock(&block_group->space_info->lock);
 662                 fragment_free_space(block_group);
 663         }
 664 #endif
 665
 666         caching_ctl->progress = (u64)-1;
 667
 668         up_read(&fs_info->commit_root_sem);
 669         btrfs_free_excluded_extents(block_group);
 670         mutex_unlock(&caching_ctl->mutex);
 671
 672         wake_up(&caching_ctl->wait);
 673
 674         btrfs_put_caching_control(caching_ctl);
 675         btrfs_put_block_group(block_group);
 676 }
 677
 678 int btrfs_cache_block_group(struct btrfs_block_group *cache, int load_cache_only)
 679 {
 680         DEFINE_WAIT(wait);
 681         struct btrfs_fs_info *fs_info = cache->fs_info;
 682         struct btrfs_caching_control *caching_ctl;
 683         int ret = 0;
 684
 685         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 686         if (!caching_ctl)
 687                 return -ENOMEM;
 688
 689         INIT_LIST_HEAD(&caching_ctl->list);
 690         mutex_init(&caching_ctl->mutex);
 691         init_waitqueue_head(&caching_ctl->wait);
 692         caching_ctl->block_group = cache;
 693         caching_ctl->progress = cache->start;
 694         refcount_set(&caching_ctl->count, 1);
 695         btrfs_init_work(&caching_ctl->work, caching_thread, NULL, NULL);
 696
 697         spin_lock(&cache->lock);
 698         /*
 699          * This should be a rare occasion, but this could happen I think in the
 700          * case where one thread starts to load the space cache info, and then
 701          * some other thread starts a transaction commit which tries to do an
 702          * allocation while the other thread is still loading the space cache
 703          * info.  The previous loop should have kept us from choosing this block
 704          * group, but if we've moved to the state where we will wait on caching
 705          * block groups we need to first check if we're doing a fast load here,
 706          * so we can wait for it to finish, otherwise we could end up allocating
 707          * from a block group who's cache gets evicted for one reason or
 708          * another.
 709          */
 710         while (cache->cached == BTRFS_CACHE_FAST) {
 711                 struct btrfs_caching_control *ctl;
 712
 713                 ctl = cache->caching_ctl;
 714                 refcount_inc(&ctl->count);
 715                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 716                 spin_unlock(&cache->lock);
 717
 718                 schedule();
 719
 720                 finish_wait(&ctl->wait, &wait);
 721                 btrfs_put_caching_control(ctl);
 722                 spin_lock(&cache->lock);
 723         }
 724
 725         if (cache->cached != BTRFS_CACHE_NO) {
 726                 spin_unlock(&cache->lock);
 727                 kfree(caching_ctl);
 728                 return 0;
 729         }
 730         WARN_ON(cache->caching_ctl);
 731         cache->caching_ctl = caching_ctl;
 732         cache->cached = BTRFS_CACHE_FAST;
 733         spin_unlock(&cache->lock);
 734
 735         if (btrfs_test_opt(fs_info, SPACE_CACHE)) {
 736                 mutex_lock(&caching_ctl->mutex);
 737                 ret = load_free_space_cache(cache);
 738
 739                 spin_lock(&cache->lock);
 740                 if (ret == 1) {
 741                         cache->caching_ctl = NULL;
 742                         cache->cached = BTRFS_CACHE_FINISHED;
 743                         cache->last_byte_to_unpin = (u64)-1;
 744                         caching_ctl->progress = (u64)-1;
 745                 } else {
 746                         if (load_cache_only) {
 747                                 cache->caching_ctl = NULL;
 748                                 cache->cached = BTRFS_CACHE_NO;
 749                         } else {
 750                                 cache->cached = BTRFS_CACHE_STARTED;
 751                                 cache->has_caching_ctl = 1;
 752                         }
 753                 }
 754                 spin_unlock(&cache->lock);
 755 #ifdef CONFIG_BTRFS_DEBUG
 756                 if (ret == 1 &&
 757                     btrfs_should_fragment_free_space(cache)) {
 758                         u64 bytes_used;
 759
 760                         spin_lock(&cache->space_info->lock);
 761                         spin_lock(&cache->lock);
 762                         bytes_used = cache->length - cache->used;
 763                         cache->space_info->bytes_used += bytes_used >> 1;
 764                         spin_unlock(&cache->lock);
 765                         spin_unlock(&cache->space_info->lock);
 766                         fragment_free_space(cache);
 767                 }
 768 #endif
 769                 mutex_unlock(&caching_ctl->mutex);
 770
 771                 wake_up(&caching_ctl->wait);
 772                 if (ret == 1) {
 773                         btrfs_put_caching_control(caching_ctl);
 774                         btrfs_free_excluded_extents(cache);
 775                         return 0;
 776                 }
 777         } else {
 778                 /*
 779                  * We're either using the free space tree or no caching at all.
 780                  * Set cached to the appropriate value and wakeup any waiters.
 781                  */
 782                 spin_lock(&cache->lock);
 783                 if (load_cache_only) {
 784                         cache->caching_ctl = NULL;
 785                         cache->cached = BTRFS_CACHE_NO;
 786                 } else {
 787                         cache->cached = BTRFS_CACHE_STARTED;
 788                         cache->has_caching_ctl = 1;
 789                 }
 790                 spin_unlock(&cache->lock);
 791                 wake_up(&caching_ctl->wait);
 792         }
 793
 794         if (load_cache_only) {
 795                 btrfs_put_caching_control(caching_ctl);
 796                 return 0;
 797         }
 798
 799         down_write(&fs_info->commit_root_sem);
 800         refcount_inc(&caching_ctl->count);
 801         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 802         up_write(&fs_info->commit_root_sem);
 803
 804         btrfs_get_block_group(cache);
 805
 806         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 807
 808         return ret;
 809 }
 810
 811 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
 812 {
 813         u64 extra_flags = chunk_to_extended(flags) &
 814                                 BTRFS_EXTENDED_PROFILE_MASK;
 815
 816         write_seqlock(&fs_info->profiles_lock);
 817         if (flags & BTRFS_BLOCK_GROUP_DATA)
 818                 fs_info->avail_data_alloc_bits &= ~extra_flags;
 819         if (flags & BTRFS_BLOCK_GROUP_METADATA)
 820                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
 821         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
 822                 fs_info->avail_system_alloc_bits &= ~extra_flags;
 823         write_sequnlock(&fs_info->profiles_lock);
 824 }
 825
 826 /*
 827  * Clear incompat bits for the following feature(s):
 828  *
 829  * - RAID56 - in case there's neither RAID5 nor RAID6 profile block group
 830  *            in the whole filesystem
 831  *
 832  * - RAID1C34 - same as above for RAID1C3 and RAID1C4 block groups
 833  */
 834 static void clear_incompat_bg_bits(struct btrfs_fs_info *fs_info, u64 flags)
 835 {
 836         bool found_raid56 = false;
 837         bool found_raid1c34 = false;
 838
 839         if ((flags & BTRFS_BLOCK_GROUP_RAID56_MASK) ||
 840             (flags & BTRFS_BLOCK_GROUP_RAID1C3) ||
 841             (flags & BTRFS_BLOCK_GROUP_RAID1C4)) {
 842                 struct list_head *head = &fs_info->space_info;
 843                 struct btrfs_space_info *sinfo;
 844
 845                 list_for_each_entry_rcu(sinfo, head, list) {
 846                         down_read(&sinfo->groups_sem);
 847                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID5]))
 848                                 found_raid56 = true;
 849                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID6]))
 850                                 found_raid56 = true;
 851                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C3]))
 852                                 found_raid1c34 = true;
 853                         if (!list_empty(&sinfo->block_groups[BTRFS_RAID_RAID1C4]))
 854                                 found_raid1c34 = true;
 855                         up_read(&sinfo->groups_sem);
 856                 }
 857                 if (!found_raid56)
 858                         btrfs_clear_fs_incompat(fs_info, RAID56);
 859                 if (!found_raid1c34)
 860                         btrfs_clear_fs_incompat(fs_info, RAID1C34);
 861         }
 862 }
 863
 864 static int remove_block_group_item(struct btrfs_trans_handle *trans,
 865                                    struct btrfs_path *path,
 866                                    struct btrfs_block_group *block_group)
 867 {
 868         struct btrfs_fs_info *fs_info = trans->fs_info;
 869         struct btrfs_root *root;
 870         struct btrfs_key key;
 871         int ret;
 872
 873         root = fs_info->extent_root;
 874         key.objectid = block_group->start;
 875         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
 876         key.offset = block_group->length;
 877
 878         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 879         if (ret > 0)
 880                 ret = -ENOENT;
 881         if (ret < 0)
 882                 return ret;
 883
 884         ret = btrfs_del_item(trans, root, path);
 885         return ret;
 886 }
 887
 888 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 889                              u64 group_start, struct extent_map *em)
 890 {
 891         struct btrfs_fs_info *fs_info = trans->fs_info;
 892         struct btrfs_path *path;
 893         struct btrfs_block_group *block_group;
 894         struct btrfs_free_cluster *cluster;
 895         struct btrfs_root *tree_root = fs_info->tree_root;
 896         struct btrfs_key key;
 897         struct inode *inode;
 898         struct kobject *kobj = NULL;
 899         int ret;
 900         int index;
 901         int factor;
 902         struct btrfs_caching_control *caching_ctl = NULL;
 903         bool remove_em;
 904         bool remove_rsv = false;
 905
 906         block_group = btrfs_lookup_block_group(fs_info, group_start);
 907         BUG_ON(!block_group);
 908         BUG_ON(!block_group->ro);
 909
 910         trace_btrfs_remove_block_group(block_group);
 911         /*
 912          * Free the reserved super bytes from this block group before
 913          * remove it.
 914          */
 915         btrfs_free_excluded_extents(block_group);
 916         btrfs_free_ref_tree_range(fs_info, block_group->start,
 917                                   block_group->length);
 918
 919         index = btrfs_bg_flags_to_raid_index(block_group->flags);
 920         factor = btrfs_bg_type_to_factor(block_group->flags);
 921
 922         /* make sure this block group isn't part of an allocation cluster */
 923         cluster = &fs_info->data_alloc_cluster;
 924         spin_lock(&cluster->refill_lock);
 925         btrfs_return_cluster_to_free_space(block_group, cluster);
 926         spin_unlock(&cluster->refill_lock);
 927
 928         /*
 929          * make sure this block group isn't part of a metadata
 930          * allocation cluster
 931          */
 932         cluster = &fs_info->meta_alloc_cluster;
 933         spin_lock(&cluster->refill_lock);
 934         btrfs_return_cluster_to_free_space(block_group, cluster);
 935         spin_unlock(&cluster->refill_lock);
 936
 937         path = btrfs_alloc_path();
 938         if (!path) {
 939                 ret = -ENOMEM;
 940                 goto out;
 941         }
 942
 943         /*
 944          * get the inode first so any iput calls done for the io_list
 945          * aren't the final iput (no unlinks allowed now)
 946          */
 947         inode = lookup_free_space_inode(block_group, path);
 948
 949         mutex_lock(&trans->transaction->cache_write_mutex);
 950         /*
 951          * Make sure our free space cache IO is done before removing the
 952          * free space inode
 953          */
 954         spin_lock(&trans->transaction->dirty_bgs_lock);
 955         if (!list_empty(&block_group->io_list)) {
 956                 list_del_init(&block_group->io_list);
 957
 958                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
 959
 960                 spin_unlock(&trans->transaction->dirty_bgs_lock);
 961                 btrfs_wait_cache_io(trans, block_group, path);
 962                 btrfs_put_block_group(block_group);
 963                 spin_lock(&trans->transaction->dirty_bgs_lock);
 964         }
 965
 966         if (!list_empty(&block_group->dirty_list)) {
 967                 list_del_init(&block_group->dirty_list);
 968                 remove_rsv = true;
 969                 btrfs_put_block_group(block_group);
 970         }
 971         spin_unlock(&trans->transaction->dirty_bgs_lock);
 972         mutex_unlock(&trans->transaction->cache_write_mutex);
 973
 974         if (!IS_ERR(inode)) {
 975                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
 976                 if (ret) {
 977                         btrfs_add_delayed_iput(inode);
 978                         goto out;
 979                 }
 980                 clear_nlink(inode);
 981                 /* One for the block groups ref */
 982                 spin_lock(&block_group->lock);
 983                 if (block_group->iref) {
 984                         block_group->iref = 0;
 985                         block_group->inode = NULL;
 986                         spin_unlock(&block_group->lock);
 987                         iput(inode);
 988                 } else {
 989                         spin_unlock(&block_group->lock);
 990                 }
 991                 /* One for our lookup ref */
 992                 btrfs_add_delayed_iput(inode);
 993         }
 994
 995         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
 996         key.type = 0;
 997         key.offset = block_group->start;
 998
 999         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
1000         if (ret < 0)
1001                 goto out;
1002         if (ret > 0)
1003                 btrfs_release_path(path);
1004         if (ret == 0) {
1005                 ret = btrfs_del_item(trans, tree_root, path);
1006                 if (ret)
1007                         goto out;
1008                 btrfs_release_path(path);
1009         }
1010
1011         spin_lock(&fs_info->block_group_cache_lock);
1012         rb_erase(&block_group->cache_node,
1013                  &fs_info->block_group_cache_tree);
1014         RB_CLEAR_NODE(&block_group->cache_node);
1015
1016         /* Once for the block groups rbtree */
1017         btrfs_put_block_group(block_group);
1018
1019         if (fs_info->first_logical_byte == block_group->start)
1020                 fs_info->first_logical_byte = (u64)-1;
1021         spin_unlock(&fs_info->block_group_cache_lock);
1022
1023         down_write(&block_group->space_info->groups_sem);
1024         /*
1025          * we must use list_del_init so people can check to see if they
1026          * are still on the list after taking the semaphore
1027          */
1028         list_del_init(&block_group->list);
1029         if (list_empty(&block_group->space_info->block_groups[index])) {
1030                 kobj = block_group->space_info->block_group_kobjs[index];
1031                 block_group->space_info->block_group_kobjs[index] = NULL;
1032                 clear_avail_alloc_bits(fs_info, block_group->flags);
1033         }
1034         up_write(&block_group->space_info->groups_sem);
1035         clear_incompat_bg_bits(fs_info, block_group->flags);
1036         if (kobj) {
1037                 kobject_del(kobj);
1038                 kobject_put(kobj);
1039         }
1040
1041         if (block_group->has_caching_ctl)
1042                 caching_ctl = btrfs_get_caching_control(block_group);
1043         if (block_group->cached == BTRFS_CACHE_STARTED)
1044                 btrfs_wait_block_group_cache_done(block_group);
1045         if (block_group->has_caching_ctl) {
1046                 down_write(&fs_info->commit_root_sem);
1047                 if (!caching_ctl) {
1048                         struct btrfs_caching_control *ctl;
1049
1050                         list_for_each_entry(ctl,
1051                                     &fs_info->caching_block_groups, list)
1052                                 if (ctl->block_group == block_group) {
1053                                         caching_ctl = ctl;
1054                                         refcount_inc(&caching_ctl->count);
1055                                         break;
1056                                 }
1057                 }
1058                 if (caching_ctl)
1059                         list_del_init(&caching_ctl->list);
1060                 up_write(&fs_info->commit_root_sem);
1061                 if (caching_ctl) {
1062                         /* Once for the caching bgs list and once for us. */
1063                         btrfs_put_caching_control(caching_ctl);
1064                         btrfs_put_caching_control(caching_ctl);
1065                 }
1066         }
1067
1068         spin_lock(&trans->transaction->dirty_bgs_lock);
1069         WARN_ON(!list_empty(&block_group->dirty_list));
1070         WARN_ON(!list_empty(&block_group->io_list));
1071         spin_unlock(&trans->transaction->dirty_bgs_lock);
1072
1073         btrfs_remove_free_space_cache(block_group);
1074
1075         spin_lock(&block_group->space_info->lock);
1076         list_del_init(&block_group->ro_list);
1077
1078         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
1079                 WARN_ON(block_group->space_info->total_bytes
1080                         < block_group->length);
1081                 WARN_ON(block_group->space_info->bytes_readonly
1082                         < block_group->length);
1083                 WARN_ON(block_group->space_info->disk_total
1084                         < block_group->length * factor);
1085         }
1086         block_group->space_info->total_bytes -= block_group->length;
1087         block_group->space_info->bytes_readonly -= block_group->length;
1088         block_group->space_info->disk_total -= block_group->length * factor;
1089
1090         spin_unlock(&block_group->space_info->lock);
1091
1092         /*
1093          * Remove the free space for the block group from the free space tree
1094          * and the block group's item from the extent tree before marking the
1095          * block group as removed. This is to prevent races with tasks that
1096          * freeze and unfreeze a block group, this task and another task
1097          * allocating a new block group - the unfreeze task ends up removing
1098          * the block group's extent map before the task calling this function
1099          * deletes the block group item from the extent tree, allowing for
1100          * another task to attempt to create another block group with the same
1101          * item key (and failing with -EEXIST and a transaction abort).
1102          */
1103         ret = remove_block_group_free_space(trans, block_group);
1104         if (ret)
1105                 goto out;
1106
1107         ret = remove_block_group_item(trans, path, block_group);
1108         if (ret < 0)
1109                 goto out;
1110
1111         spin_lock(&block_group->lock);
1112         block_group->removed = 1;
1113         /*
1114          * At this point trimming or scrub can't start on this block group,
1115          * because we removed the block group from the rbtree
1116          * fs_info->block_group_cache_tree so no one can't find it anymore and
1117          * even if someone already got this block group before we removed it
1118          * from the rbtree, they have already incremented block_group->frozen -
1119          * if they didn't, for the trimming case they won't find any free space
1120          * entries because we already removed them all when we called
1121          * btrfs_remove_free_space_cache().
1122          *
1123          * And we must not remove the extent map from the fs_info->mapping_tree
1124          * to prevent the same logical address range and physical device space
1125          * ranges from being reused for a new block group. This is needed to
1126          * avoid races with trimming and scrub.
1127          *
1128          * An fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
1129          * completely transactionless, so while it is trimming a range the
1130          * currently running transaction might finish and a new one start,
1131          * allowing for new block groups to be created that can reuse the same
1132          * physical device locations unless we take this special care.
1133          *
1134          * There may also be an implicit trim operation if the file system
1135          * is mounted with -odiscard. The same protections must remain
1136          * in place until the extents have been discarded completely when
1137          * the transaction commit has completed.
1138          */
1139         remove_em = (atomic_read(&block_group->frozen) == 0);
1140         spin_unlock(&block_group->lock);
1141
1142         if (remove_em) {
1143                 struct extent_map_tree *em_tree;
1144
1145                 em_tree = &fs_info->mapping_tree;
1146                 write_lock(&em_tree->lock);
1147                 remove_extent_mapping(em_tree, em);
1148                 write_unlock(&em_tree->lock);
1149                 /* once for the tree */
1150                 free_extent_map(em);
1151         }
1152
1153 out:
1154         /* Once for the lookup reference */
1155         btrfs_put_block_group(block_group);
1156         if (remove_rsv)
1157                 btrfs_delayed_refs_rsv_release(fs_info, 1);
1158         btrfs_free_path(path);
1159         return ret;
1160 }
1161
1162 struct btrfs_trans_handle *btrfs_start_trans_remove_block_group(
1163                 struct btrfs_fs_info *fs_info, const u64 chunk_offset)
1164 {
1165         struct extent_map_tree *em_tree = &fs_info->mapping_tree;
1166         struct extent_map *em;
1167         struct map_lookup *map;
1168         unsigned int num_items;
1169
1170         read_lock(&em_tree->lock);
1171         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1172         read_unlock(&em_tree->lock);
1173         ASSERT(em && em->start == chunk_offset);
1174
1175         /*
1176          * We need to reserve 3 + N units from the metadata space info in order
1177          * to remove a block group (done at btrfs_remove_chunk() and at
1178          * btrfs_remove_block_group()), which are used for:
1179          *
1180          * 1 unit for adding the free space inode's orphan (located in the tree
1181          * of tree roots).
1182          * 1 unit for deleting the block group item (located in the extent
1183          * tree).
1184          * 1 unit for deleting the free space item (located in tree of tree
1185          * roots).
1186          * N units for deleting N device extent items corresponding to each
1187          * stripe (located in the device tree).
1188          *
1189          * In order to remove a block group we also need to reserve units in the
1190          * system space info in order to update the chunk tree (update one or
1191          * more device items and remove one chunk item), but this is done at
1192          * btrfs_remove_chunk() through a call to check_system_chunk().
1193          */
1194         map = em->map_lookup;
1195         num_items = 3 + map->num_stripes;
1196         free_extent_map(em);
1197
1198         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
1199                                                            num_items);
1200 }
1201
1202 /*
1203  * Mark block group @cache read-only, so later write won't happen to block
1204  * group @cache.
1205  *
1206  * If @force is not set, this function will only mark the block group readonly
1207  * if we have enough free space (1M) in other metadata/system block groups.
1208  * If @force is not set, this function will mark the block group readonly
1209  * without checking free space.
1210  *
1211  * NOTE: This function doesn't care if other block groups can contain all the
1212  * data in this block group. That check should be done by relocation routine,
1213  * not this function.
1214  */
1215 static int inc_block_group_ro(struct btrfs_block_group *cache, int force)
1216 {
1217         struct btrfs_space_info *sinfo = cache->space_info;
1218         u64 num_bytes;
1219         int ret = -ENOSPC;
1220
1221         spin_lock(&sinfo->lock);
1222         spin_lock(&cache->lock);
1223
1224         if (cache->ro) {
1225                 cache->ro++;
1226                 ret = 0;
1227                 goto out;
1228         }
1229
1230         num_bytes = cache->length - cache->reserved - cache->pinned -
1231                     cache->bytes_super - cache->used;
1232
1233         /*
1234          * Data never overcommits, even in mixed mode, so do just the straight
1235          * check of left over space in how much we have allocated.
1236          */
1237         if (force) {
1238                 ret = 0;
1239         } else if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA) {
1240                 u64 sinfo_used = btrfs_space_info_used(sinfo, true);
1241
1242                 /*
1243                  * Here we make sure if we mark this bg RO, we still have enough
1244                  * free space as buffer.
1245                  */
1246                 if (sinfo_used + num_bytes <= sinfo->total_bytes)
1247                         ret = 0;
1248         } else {
1249                 /*
1250                  * We overcommit metadata, so we need to do the
1251                  * btrfs_can_overcommit check here, and we need to pass in
1252                  * BTRFS_RESERVE_NO_FLUSH to give ourselves the most amount of
1253                  * leeway to allow us to mark this block group as read only.
1254                  */
1255                 if (btrfs_can_overcommit(cache->fs_info, sinfo, num_bytes,
1256                                          BTRFS_RESERVE_NO_FLUSH))
1257                         ret = 0;
1258         }
1259
1260         if (!ret) {
1261                 sinfo->bytes_readonly += num_bytes;
1262                 cache->ro++;
1263                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
1264         }
1265 out:
1266         spin_unlock(&cache->lock);
1267         spin_unlock(&sinfo->lock);
1268         if (ret == -ENOSPC && btrfs_test_opt(cache->fs_info, ENOSPC_DEBUG)) {
1269                 btrfs_info(cache->fs_info,
1270                         "unable to make block group %llu ro", cache->start);
1271                 btrfs_dump_space_info(cache->fs_info, cache->space_info, 0, 0);
1272         }
1273         return ret;
1274 }
1275
1276 static bool clean_pinned_extents(struct btrfs_trans_handle *trans,
1277                                  struct btrfs_block_group *bg)
1278 {
1279         struct btrfs_fs_info *fs_info = bg->fs_info;
1280         struct btrfs_transaction *prev_trans = NULL;
1281         const u64 start = bg->start;
1282         const u64 end = start + bg->length - 1;
1283         int ret;
1284
1285         spin_lock(&fs_info->trans_lock);
1286         if (trans->transaction->list.prev != &fs_info->trans_list) {
1287                 prev_trans = list_last_entry(&trans->transaction->list,
1288                                              struct btrfs_transaction, list);
1289                 refcount_inc(&prev_trans->use_count);
1290         }
1291         spin_unlock(&fs_info->trans_lock);
1292
1293         /*
1294          * Hold the unused_bg_unpin_mutex lock to avoid racing with
1295          * btrfs_finish_extent_commit(). If we are at transaction N, another
1296          * task might be running finish_extent_commit() for the previous
1297          * transaction N - 1, and have seen a range belonging to the block
1298          * group in pinned_extents before we were able to clear the whole block
1299          * group range from pinned_extents. This means that task can lookup for
1300          * the block group after we unpinned it from pinned_extents and removed
1301          * it, leading to a BUG_ON() at unpin_extent_range().
1302          */
1303         mutex_lock(&fs_info->unused_bg_unpin_mutex);
1304         if (prev_trans) {
1305                 ret = clear_extent_bits(&prev_trans->pinned_extents, start, end,
1306                                         EXTENT_DIRTY);
1307                 if (ret)
1308                         goto out;
1309         }
1310
1311         ret = clear_extent_bits(&trans->transaction->pinned_extents, start, end,
1312                                 EXTENT_DIRTY);
1313 out:
1314         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
1315         if (prev_trans)
1316                 btrfs_put_transaction(prev_trans);
1317
1318         return ret == 0;
1319 }
1320
1321 /*
1322  * Process the unused_bgs list and remove any that don't have any allocated
1323  * space inside of them.
1324  */
1325 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
1326 {
1327         struct btrfs_block_group *block_group;
1328         struct btrfs_space_info *space_info;
1329         struct btrfs_trans_handle *trans;
1330         const bool async_trim_enabled = btrfs_test_opt(fs_info, DISCARD_ASYNC);
1331         int ret = 0;
1332
1333         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1334                 return;
1335
1336         spin_lock(&fs_info->unused_bgs_lock);
1337         while (!list_empty(&fs_info->unused_bgs)) {
1338                 int trimming;
1339
1340                 block_group = list_first_entry(&fs_info->unused_bgs,
1341                                                struct btrfs_block_group,
1342                                                bg_list);
1343                 list_del_init(&block_group->bg_list);
1344
1345                 space_info = block_group->space_info;
1346
1347                 if (ret || btrfs_mixed_space_info(space_info)) {
1348                         btrfs_put_block_group(block_group);
1349                         continue;
1350                 }
1351                 spin_unlock(&fs_info->unused_bgs_lock);
1352
1353                 btrfs_discard_cancel_work(&fs_info->discard_ctl, block_group);
1354
1355                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
1356
1357                 /* Don't want to race with allocators so take the groups_sem */
1358                 down_write(&space_info->groups_sem);
1359
1360                 /*
1361                  * Async discard moves the final block group discard to be prior
1362                  * to the unused_bgs code path.  Therefore, if it's not fully
1363                  * trimmed, punt it back to the async discard lists.
1364                  */
1365                 if (btrfs_test_opt(fs_info, DISCARD_ASYNC) &&
1366                     !btrfs_is_free_space_trimmed(block_group)) {
1367                         trace_btrfs_skip_unused_block_group(block_group);
1368                         up_write(&space_info->groups_sem);
1369                         /* Requeue if we failed because of async discard */
1370                         btrfs_discard_queue_work(&fs_info->discard_ctl,
1371                                                  block_group);
1372                         goto next;
1373                 }
1374
1375                 spin_lock(&block_group->lock);
1376                 if (block_group->reserved || block_group->pinned ||
1377                     block_group->used || block_group->ro ||
1378                     list_is_singular(&block_group->list)) {
1379                         /*
1380                          * We want to bail if we made new allocations or have
1381                          * outstanding allocations in this block group.  We do
1382                          * the ro check in case balance is currently acting on
1383                          * this block group.
1384                          */
1385                         trace_btrfs_skip_unused_block_group(block_group);
1386                         spin_unlock(&block_group->lock);
1387                         up_write(&space_info->groups_sem);
1388                         goto next;
1389                 }
1390                 spin_unlock(&block_group->lock);
1391
1392                 /* We don't want to force the issue, only flip if it's ok. */
1393                 ret = inc_block_group_ro(block_group, 0);
1394                 up_write(&space_info->groups_sem);
1395                 if (ret < 0) {
1396                         ret = 0;
1397                         goto next;
1398                 }
1399
1400                 /*
1401                  * Want to do this before we do anything else so we can recover
1402                  * properly if we fail to join the transaction.
1403                  */
1404                 trans = btrfs_start_trans_remove_block_group(fs_info,
1405                                                      block_group->start);
1406                 if (IS_ERR(trans)) {
1407                         btrfs_dec_block_group_ro(block_group);
1408                         ret = PTR_ERR(trans);
1409                         goto next;
1410                 }
1411
1412                 /*
1413                  * We could have pending pinned extents for this block group,
1414                  * just delete them, we don't care about them anymore.
1415                  */
1416                 if (!clean_pinned_extents(trans, block_group)) {
1417                         btrfs_dec_block_group_ro(block_group);
1418                         goto end_trans;
1419                 }
1420
1421                 /*
1422                  * At this point, the block_group is read only and should fail
1423                  * new allocations.  However, btrfs_finish_extent_commit() can
1424                  * cause this block_group to be placed back on the discard
1425                  * lists because now the block_group isn't fully discarded.
1426                  * Bail here and try again later after discarding everything.
1427                  */
1428                 spin_lock(&fs_info->discard_ctl.lock);
1429                 if (!list_empty(&block_group->discard_list)) {
1430                         spin_unlock(&fs_info->discard_ctl.lock);
1431                         btrfs_dec_block_group_ro(block_group);
1432                         btrfs_discard_queue_work(&fs_info->discard_ctl,
1433                                                  block_group);
1434                         goto end_trans;
1435                 }
1436                 spin_unlock(&fs_info->discard_ctl.lock);
1437
1438                 /* Reset pinned so btrfs_put_block_group doesn't complain */
1439                 spin_lock(&space_info->lock);
1440                 spin_lock(&block_group->lock);
1441
1442                 btrfs_space_info_update_bytes_pinned(fs_info, space_info,
1443                                                      -block_group->pinned);
1444                 space_info->bytes_readonly += block_group->pinned;
1445                 percpu_counter_add_batch(&space_info->total_bytes_pinned,
1446                                    -block_group->pinned,
1447                                    BTRFS_TOTAL_BYTES_PINNED_BATCH);
1448                 block_group->pinned = 0;
1449
1450                 spin_unlock(&block_group->lock);
1451                 spin_unlock(&space_info->lock);
1452
1453                 /*
1454                  * The normal path here is an unused block group is passed here,
1455                  * then trimming is handled in the transaction commit path.
1456                  * Async discard interposes before this to do the trimming
1457                  * before coming down the unused block group path as trimming
1458                  * will no longer be done later in the transaction commit path.
1459                  */
1460                 if (!async_trim_enabled && btrfs_test_opt(fs_info, DISCARD_ASYNC))
1461                         goto flip_async;
1462
1463                 /* DISCARD can flip during remount */
1464                 trimming = btrfs_test_opt(fs_info, DISCARD_SYNC);
1465
1466                 /* Implicit trim during transaction commit. */
1467                 if (trimming)
1468                         btrfs_freeze_block_group(block_group);
1469
1470                 /*
1471                  * Btrfs_remove_chunk will abort the transaction if things go
1472                  * horribly wrong.
1473                  */
1474                 ret = btrfs_remove_chunk(trans, block_group->start);
1475
1476                 if (ret) {
1477                         if (trimming)
1478                                 btrfs_unfreeze_block_group(block_group);
1479                         goto end_trans;
1480                 }
1481
1482                 /*
1483                  * If we're not mounted with -odiscard, we can just forget
1484                  * about this block group. Otherwise we'll need to wait
1485                  * until transaction commit to do the actual discard.
1486                  */
1487                 if (trimming) {
1488                         spin_lock(&fs_info->unused_bgs_lock);
1489                         /*
1490                          * A concurrent scrub might have added us to the list
1491                          * fs_info->unused_bgs, so use a list_move operation
1492                          * to add the block group to the deleted_bgs list.
1493                          */
1494                         list_move(&block_group->bg_list,
1495                                   &trans->transaction->deleted_bgs);
1496                         spin_unlock(&fs_info->unused_bgs_lock);
1497                         btrfs_get_block_group(block_group);
1498                 }
1499 end_trans:
1500                 btrfs_end_transaction(trans);
1501 next:
1502                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
1503                 btrfs_put_block_group(block_group);
1504                 spin_lock(&fs_info->unused_bgs_lock);
1505         }
1506         spin_unlock(&fs_info->unused_bgs_lock);
1507         return;
1508
1509 flip_async:
1510         btrfs_end_transaction(trans);
1511         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
1512         btrfs_put_block_group(block_group);
1513         btrfs_discard_punt_unused_bgs_list(fs_info);
1514 }
1515
1516 void btrfs_mark_bg_unused(struct btrfs_block_group *bg)
1517 {
1518         struct btrfs_fs_info *fs_info = bg->fs_info;
1519
1520         spin_lock(&fs_info->unused_bgs_lock);
1521         if (list_empty(&bg->bg_list)) {
1522                 btrfs_get_block_group(bg);
1523                 trace_btrfs_add_unused_block_group(bg);
1524                 list_add_tail(&bg->bg_list, &fs_info->unused_bgs);
1525         }
1526         spin_unlock(&fs_info->unused_bgs_lock);
1527 }
1528
1529 static int read_bg_from_eb(struct btrfs_fs_info *fs_info, struct btrfs_key *key,
1530                            struct btrfs_path *path)
1531 {
1532         struct extent_map_tree *em_tree;
1533         struct extent_map *em;
1534         struct btrfs_block_group_item bg;
1535         struct extent_buffer *leaf;
1536         int slot;
1537         u64 flags;
1538         int ret = 0;
1539
1540         slot = path->slots[0];
1541         leaf = path->nodes[0];
1542
1543         em_tree = &fs_info->mapping_tree;
1544         read_lock(&em_tree->lock);
1545         em = lookup_extent_mapping(em_tree, key->objectid, key->offset);
1546         read_unlock(&em_tree->lock);
1547         if (!em) {
1548                 btrfs_err(fs_info,
1549                           "logical %llu len %llu found bg but no related chunk",
1550                           key->objectid, key->offset);
1551                 return -ENOENT;
1552         }
1553
1554         if (em->start != key->objectid || em->len != key->offset) {
1555                 btrfs_err(fs_info,
1556                         "block group %llu len %llu mismatch with chunk %llu len %llu",
1557                         key->objectid, key->offset, em->start, em->len);
1558                 ret = -EUCLEAN;
1559                 goto out_free_em;
1560         }
1561
1562         read_extent_buffer(leaf, &bg, btrfs_item_ptr_offset(leaf, slot),
1563                            sizeof(bg));
1564         flags = btrfs_stack_block_group_flags(&bg) &
1565                 BTRFS_BLOCK_GROUP_TYPE_MASK;
1566
1567         if (flags != (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1568                 btrfs_err(fs_info,
1569 "block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
1570                           key->objectid, key->offset, flags,
1571                           (BTRFS_BLOCK_GROUP_TYPE_MASK & em->map_lookup->type));
1572                 ret = -EUCLEAN;
1573         }
1574
1575 out_free_em:
1576         free_extent_map(em);
1577         return ret;
1578 }
1579
1580 static int find_first_block_group(struct btrfs_fs_info *fs_info,
1581                                   struct btrfs_path *path,
1582                                   struct btrfs_key *key)
1583 {
1584         struct btrfs_root *root = fs_info->extent_root;
1585         int ret;
1586         struct btrfs_key found_key;
1587         struct extent_buffer *leaf;
1588         int slot;
1589
1590         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
1591         if (ret < 0)
1592                 return ret;
1593
1594         while (1) {
1595                 slot = path->slots[0];
1596                 leaf = path->nodes[0];
1597                 if (slot >= btrfs_header_nritems(leaf)) {
1598                         ret = btrfs_next_leaf(root, path);
1599                         if (ret == 0)
1600                                 continue;
1601                         if (ret < 0)
1602                                 goto out;
1603                         break;
1604                 }
1605                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1606
1607                 if (found_key.objectid >= key->objectid &&
1608                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1609                         ret = read_bg_from_eb(fs_info, &found_key, path);
1610                         break;
1611                 }
1612
1613                 path->slots[0]++;
1614         }
1615 out:
1616         return ret;
1617 }
1618
1619 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1620 {
1621         u64 extra_flags = chunk_to_extended(flags) &
1622                                 BTRFS_EXTENDED_PROFILE_MASK;
1623
1624         write_seqlock(&fs_info->profiles_lock);
1625         if (flags & BTRFS_BLOCK_GROUP_DATA)
1626                 fs_info->avail_data_alloc_bits |= extra_flags;
1627         if (flags & BTRFS_BLOCK_GROUP_METADATA)
1628                 fs_info->avail_metadata_alloc_bits |= extra_flags;
1629         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1630                 fs_info->avail_system_alloc_bits |= extra_flags;
1631         write_sequnlock(&fs_info->profiles_lock);
1632 }
1633
1634 /**
1635  * btrfs_rmap_block - Map a physical disk address to a list of logical addresses
1636  * @chunk_start:   logical address of block group
1637  * @physical:      physical address to map to logical addresses
1638  * @logical:       return array of logical addresses which map to @physical
1639  * @naddrs:        length of @logical
1640  * @stripe_len:    size of IO stripe for the given block group
1641  *
1642  * Maps a particular @physical disk address to a list of @logical addresses.
1643  * Used primarily to exclude those portions of a block group that contain super
1644  * block copies.
1645  */
1646 EXPORT_FOR_TESTS
1647 int btrfs_rmap_block(struct btrfs_fs_info *fs_info, u64 chunk_start,
1648                      u64 physical, u64 **logical, int *naddrs, int *stripe_len)
1649 {
1650         struct extent_map *em;
1651         struct map_lookup *map;
1652         u64 *buf;
1653         u64 bytenr;
1654         u64 data_stripe_length;
1655         u64 io_stripe_size;
1656         int i, nr = 0;
1657         int ret = 0;
1658
1659         em = btrfs_get_chunk_map(fs_info, chunk_start, 1);
1660         if (IS_ERR(em))
1661                 return -EIO;
1662
1663         map = em->map_lookup;
1664         data_stripe_length = em->orig_block_len;
1665         io_stripe_size = map->stripe_len;
1666
1667         /* For RAID5/6 adjust to a full IO stripe length */
1668         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
1669                 io_stripe_size = map->stripe_len * nr_data_stripes(map);
1670
1671         buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
1672         if (!buf) {
1673                 ret = -ENOMEM;
1674                 goto out;
1675         }
1676
1677         for (i = 0; i < map->num_stripes; i++) {
1678                 bool already_inserted = false;
1679                 u64 stripe_nr;
1680                 int j;
1681
1682                 if (!in_range(physical, map->stripes[i].physical,
1683                               data_stripe_length))
1684                         continue;
1685
1686                 stripe_nr = physical - map->stripes[i].physical;
1687                 stripe_nr = div64_u64(stripe_nr, map->stripe_len);
1688
1689                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1690                         stripe_nr = stripe_nr * map->num_stripes + i;
1691                         stripe_nr = div_u64(stripe_nr, map->sub_stripes);
1692                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
1693                         stripe_nr = stripe_nr * map->num_stripes + i;
1694                 }
1695                 /*
1696                  * The remaining case would be for RAID56, multiply by
1697                  * nr_data_stripes().  Alternatively, just use rmap_len below
1698                  * instead of map->stripe_len
1699                  */
1700
1701                 bytenr = chunk_start + stripe_nr * io_stripe_size;
1702
1703                 /* Ensure we don't add duplicate addresses */
1704                 for (j = 0; j < nr; j++) {
1705                         if (buf[j] == bytenr) {
1706                                 already_inserted = true;
1707                                 break;
1708                         }
1709                 }
1710
1711                 if (!already_inserted)
1712                         buf[nr++] = bytenr;
1713         }
1714
1715         *logical = buf;
1716         *naddrs = nr;
1717         *stripe_len = io_stripe_size;
1718 out:
1719         free_extent_map(em);
1720         return ret;
1721 }
1722
1723 static int exclude_super_stripes(struct btrfs_block_group *cache)
1724 {
1725         struct btrfs_fs_info *fs_info = cache->fs_info;
1726         u64 bytenr;
1727         u64 *logical;
1728         int stripe_len;
1729         int i, nr, ret;
1730
1731         if (cache->start < BTRFS_SUPER_INFO_OFFSET) {
1732                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->start;
1733                 cache->bytes_super += stripe_len;
1734                 ret = btrfs_add_excluded_extent(fs_info, cache->start,
1735                                                 stripe_len);
1736                 if (ret)
1737                         return ret;
1738         }
1739
1740         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1741                 bytenr = btrfs_sb_offset(i);
1742                 ret = btrfs_rmap_block(fs_info, cache->start,
1743                                        bytenr, &logical, &nr, &stripe_len);
1744                 if (ret)
1745                         return ret;
1746
1747                 while (nr--) {
1748                         u64 len = min_t(u64, stripe_len,
1749                                 cache->start + cache->length - logical[nr]);
1750
1751                         cache->bytes_super += len;
1752                         ret = btrfs_add_excluded_extent(fs_info, logical[nr],
1753                                                         len);
1754                         if (ret) {
1755                                 kfree(logical);
1756                                 return ret;
1757                         }
1758                 }
1759
1760                 kfree(logical);
1761         }
1762         return 0;
1763 }
1764
1765 static void link_block_group(struct btrfs_block_group *cache)
1766 {
1767         struct btrfs_space_info *space_info = cache->space_info;
1768         int index = btrfs_bg_flags_to_raid_index(cache->flags);
1769
1770         down_write(&space_info->groups_sem);
1771         list_add_tail(&cache->list, &space_info->block_groups[index]);
1772         up_write(&space_info->groups_sem);
1773 }
1774
1775 static struct btrfs_block_group *btrfs_create_block_group_cache(
1776                 struct btrfs_fs_info *fs_info, u64 start)
1777 {
1778         struct btrfs_block_group *cache;
1779
1780         cache = kzalloc(sizeof(*cache), GFP_NOFS);
1781         if (!cache)
1782                 return NULL;
1783
1784         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
1785                                         GFP_NOFS);
1786         if (!cache->free_space_ctl) {
1787                 kfree(cache);
1788                 return NULL;
1789         }
1790
1791         cache->start = start;
1792
1793         cache->fs_info = fs_info;
1794         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
1795
1796         cache->discard_index = BTRFS_DISCARD_INDEX_UNUSED;
1797
1798         refcount_set(&cache->refs, 1);
1799         spin_lock_init(&cache->lock);
1800         init_rwsem(&cache->data_rwsem);
1801         INIT_LIST_HEAD(&cache->list);
1802         INIT_LIST_HEAD(&cache->cluster_list);
1803         INIT_LIST_HEAD(&cache->bg_list);
1804         INIT_LIST_HEAD(&cache->ro_list);
1805         INIT_LIST_HEAD(&cache->discard_list);
1806         INIT_LIST_HEAD(&cache->dirty_list);
1807         INIT_LIST_HEAD(&cache->io_list);
1808         btrfs_init_free_space_ctl(cache);
1809         atomic_set(&cache->frozen, 0);
1810         mutex_init(&cache->free_space_lock);
1811         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
1812
1813         return cache;
1814 }
1815
1816 /*
1817  * Iterate all chunks and verify that each of them has the corresponding block
1818  * group
1819  */
1820 static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
1821 {
1822         struct extent_map_tree *map_tree = &fs_info->mapping_tree;
1823         struct extent_map *em;
1824         struct btrfs_block_group *bg;
1825         u64 start = 0;
1826         int ret = 0;
1827
1828         while (1) {
1829                 read_lock(&map_tree->lock);
1830                 /*
1831                  * lookup_extent_mapping will return the first extent map
1832                  * intersecting the range, so setting @len to 1 is enough to
1833                  * get the first chunk.
1834                  */
1835                 em = lookup_extent_mapping(map_tree, start, 1);
1836                 read_unlock(&map_tree->lock);
1837                 if (!em)
1838                         break;
1839
1840                 bg = btrfs_lookup_block_group(fs_info, em->start);
1841                 if (!bg) {
1842                         btrfs_err(fs_info,
1843         "chunk start=%llu len=%llu doesn't have corresponding block group",
1844                                      em->start, em->len);
1845                         ret = -EUCLEAN;
1846                         free_extent_map(em);
1847                         break;
1848                 }
1849                 if (bg->start != em->start || bg->length != em->len ||
1850                     (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
1851                     (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
1852                         btrfs_err(fs_info,
1853 "chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
1854                                 em->start, em->len,
1855                                 em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
1856                                 bg->start, bg->length,
1857                                 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
1858                         ret = -EUCLEAN;
1859                         free_extent_map(em);
1860                         btrfs_put_block_group(bg);
1861                         break;
1862                 }
1863                 start = em->start + em->len;
1864                 free_extent_map(em);
1865                 btrfs_put_block_group(bg);
1866         }
1867         return ret;
1868 }
1869
1870 static void read_block_group_item(struct btrfs_block_group *cache,
1871                                  struct btrfs_path *path,
1872                                  const struct btrfs_key *key)
1873 {
1874         struct extent_buffer *leaf = path->nodes[0];
1875         struct btrfs_block_group_item bgi;
1876         int slot = path->slots[0];
1877
1878         cache->length = key->offset;
1879
1880         read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot),
1881                            sizeof(bgi));
1882         cache->used = btrfs_stack_block_group_used(&bgi);
1883         cache->flags = btrfs_stack_block_group_flags(&bgi);
1884 }
1885
1886 static int read_one_block_group(struct btrfs_fs_info *info,
1887                                 struct btrfs_path *path,
1888                                 const struct btrfs_key *key,
1889                                 int need_clear)
1890 {
1891         struct btrfs_block_group *cache;
1892         struct btrfs_space_info *space_info;
1893         const bool mixed = btrfs_fs_incompat(info, MIXED_GROUPS);
1894         int ret;
1895
1896         ASSERT(key->type == BTRFS_BLOCK_GROUP_ITEM_KEY);
1897
1898         cache = btrfs_create_block_group_cache(info, key->objectid);
1899         if (!cache)
1900                 return -ENOMEM;
1901
1902         read_block_group_item(cache, path, key);
1903
1904         set_free_space_tree_thresholds(cache);
1905
1906         if (need_clear) {
1907                 /*
1908                  * When we mount with old space cache, we need to
1909                  * set BTRFS_DC_CLEAR and set dirty flag.
1910                  *
1911                  * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
1912                  *    truncate the old free space cache inode and
1913                  *    setup a new one.
1914                  * b) Setting 'dirty flag' makes sure that we flush
1915                  *    the new space cache info onto disk.
1916                  */
1917                 if (btrfs_test_opt(info, SPACE_CACHE))
1918                         cache->disk_cache_state = BTRFS_DC_CLEAR;
1919         }
1920         if (!mixed && ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
1921             (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
1922                         btrfs_err(info,
1923 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
1924                                   cache->start);
1925                         ret = -EINVAL;
1926                         goto error;
1927         }
1928
1929         /*
1930          * We need to exclude the super stripes now so that the space info has
1931          * super bytes accounted for, otherwise we'll think we have more space
1932          * than we actually do.
1933          */
1934         ret = exclude_super_stripes(cache);
1935         if (ret) {
1936                 /* We may have excluded something, so call this just in case. */
1937                 btrfs_free_excluded_extents(cache);
1938                 goto error;
1939         }
1940
1941         /*
1942          * Check for two cases, either we are full, and therefore don't need
1943          * to bother with the caching work since we won't find any space, or we
1944          * are empty, and we can just add all the space in and be done with it.
1945          * This saves us _a_lot_ of time, particularly in the full case.
1946          */
1947         if (cache->length == cache->used) {
1948                 cache->last_byte_to_unpin = (u64)-1;
1949                 cache->cached = BTRFS_CACHE_FINISHED;
1950                 btrfs_free_excluded_extents(cache);
1951         } else if (cache->used == 0) {
1952                 cache->last_byte_to_unpin = (u64)-1;
1953                 cache->cached = BTRFS_CACHE_FINISHED;
1954                 add_new_free_space(cache, cache->start,
1955                                    cache->start + cache->length);
1956                 btrfs_free_excluded_extents(cache);
1957         }
1958
1959         ret = btrfs_add_block_group_cache(info, cache);
1960         if (ret) {
1961                 btrfs_remove_free_space_cache(cache);
1962                 goto error;
1963         }
1964         trace_btrfs_add_block_group(info, cache, 0);
1965         btrfs_update_space_info(info, cache->flags, cache->length,
1966                                 cache->used, cache->bytes_super, &space_info);
1967
1968         cache->space_info = space_info;
1969
1970         link_block_group(cache);
1971
1972         set_avail_alloc_bits(info, cache->flags);
1973         if (btrfs_chunk_readonly(info, cache->start)) {
1974                 inc_block_group_ro(cache, 1);
1975         } else if (cache->used == 0) {
1976                 ASSERT(list_empty(&cache->bg_list));
1977                 if (btrfs_test_opt(info, DISCARD_ASYNC))
1978                         btrfs_discard_queue_work(&info->discard_ctl, cache);
1979                 else
1980                         btrfs_mark_bg_unused(cache);
1981         }
1982         return 0;
1983 error:
1984         btrfs_put_block_group(cache);
1985         return ret;
1986 }
1987
1988 int btrfs_read_block_groups(struct btrfs_fs_info *info)
1989 {
1990         struct btrfs_path *path;
1991         int ret;
1992         struct btrfs_block_group *cache;
1993         struct btrfs_space_info *space_info;
1994         struct btrfs_key key;
1995         int need_clear = 0;
1996         u64 cache_gen;
1997
1998         key.objectid = 0;
1999         key.offset = 0;
2000         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2001         path = btrfs_alloc_path();
2002         if (!path)
2003                 return -ENOMEM;
2004
2005         cache_gen = btrfs_super_cache_generation(info->super_copy);
2006         if (btrfs_test_opt(info, SPACE_CACHE) &&
2007             btrfs_super_generation(info->super_copy) != cache_gen)
2008                 need_clear = 1;
2009         if (btrfs_test_opt(info, CLEAR_CACHE))
2010                 need_clear = 1;
2011
2012         while (1) {
2013                 ret = find_first_block_group(info, path, &key);
2014                 if (ret > 0)
2015                         break;
2016                 if (ret != 0)
2017                         goto error;
2018
2019                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
2020                 ret = read_one_block_group(info, path, &key, need_clear);
2021                 if (ret < 0)
2022                         goto error;
2023                 key.objectid += key.offset;
2024                 key.offset = 0;
2025                 btrfs_release_path(path);
2026         }
2027
2028         list_for_each_entry(space_info, &info->space_info, list) {
2029                 int i;
2030
2031                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
2032                         if (list_empty(&space_info->block_groups[i]))
2033                                 continue;
2034                         cache = list_first_entry(&space_info->block_groups[i],
2035                                                  struct btrfs_block_group,
2036                                                  list);
2037                         btrfs_sysfs_add_block_group_type(cache);
2038                 }
2039
2040                 if (!(btrfs_get_alloc_profile(info, space_info->flags) &
2041                       (BTRFS_BLOCK_GROUP_RAID10 |
2042                        BTRFS_BLOCK_GROUP_RAID1_MASK |
2043                        BTRFS_BLOCK_GROUP_RAID56_MASK |
2044                        BTRFS_BLOCK_GROUP_DUP)))
2045                         continue;
2046                 /*
2047                  * Avoid allocating from un-mirrored block group if there are
2048                  * mirrored block groups.
2049                  */
2050                 list_for_each_entry(cache,
2051                                 &space_info->block_groups[BTRFS_RAID_RAID0],
2052                                 list)
2053                         inc_block_group_ro(cache, 1);
2054                 list_for_each_entry(cache,
2055                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
2056                                 list)
2057                         inc_block_group_ro(cache, 1);
2058         }
2059
2060         btrfs_init_global_block_rsv(info);
2061         ret = check_chunk_block_group_mappings(info);
2062 error:
2063         btrfs_free_path(path);
2064         return ret;
2065 }
2066
2067 static int insert_block_group_item(struct btrfs_trans_handle *trans,
2068                                    struct btrfs_block_group *block_group)
2069 {
2070         struct btrfs_fs_info *fs_info = trans->fs_info;
2071         struct btrfs_block_group_item bgi;
2072         struct btrfs_root *root;
2073         struct btrfs_key key;
2074
2075         spin_lock(&block_group->lock);
2076         btrfs_set_stack_block_group_used(&bgi, block_group->used);
2077         btrfs_set_stack_block_group_chunk_objectid(&bgi,
2078                                 BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2079         btrfs_set_stack_block_group_flags(&bgi, block_group->flags);
2080         key.objectid = block_group->start;
2081         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2082         key.offset = block_group->length;
2083         spin_unlock(&block_group->lock);
2084
2085         root = fs_info->extent_root;
2086         return btrfs_insert_item(trans, root, &key, &bgi, sizeof(bgi));
2087 }
2088
2089 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans)
2090 {
2091         struct btrfs_fs_info *fs_info = trans->fs_info;
2092         struct btrfs_block_group *block_group;
2093         int ret = 0;
2094
2095         if (!trans->can_flush_pending_bgs)
2096                 return;
2097
2098         while (!list_empty(&trans->new_bgs)) {
2099                 int index;
2100
2101                 block_group = list_first_entry(&trans->new_bgs,
2102                                                struct btrfs_block_group,
2103                                                bg_list);
2104                 if (ret)
2105                         goto next;
2106
2107                 index = btrfs_bg_flags_to_raid_index(block_group->flags);
2108
2109                 ret = insert_block_group_item(trans, block_group);
2110                 if (ret)
2111                         btrfs_abort_transaction(trans, ret);
2112                 ret = btrfs_finish_chunk_alloc(trans, block_group->start,
2113                                         block_group->length);
2114                 if (ret)
2115                         btrfs_abort_transaction(trans, ret);
2116                 add_block_group_free_space(trans, block_group);
2117
2118                 /*
2119                  * If we restriped during balance, we may have added a new raid
2120                  * type, so now add the sysfs entries when it is safe to do so.
2121                  * We don't have to worry about locking here as it's handled in
2122                  * btrfs_sysfs_add_block_group_type.
2123                  */
2124                 if (block_group->space_info->block_group_kobjs[index] == NULL)
2125                         btrfs_sysfs_add_block_group_type(block_group);
2126
2127                 /* Already aborted the transaction if it failed. */
2128 next:
2129                 btrfs_delayed_refs_rsv_release(fs_info, 1);
2130                 list_del_init(&block_group->bg_list);
2131         }
2132         btrfs_trans_release_chunk_metadata(trans);
2133 }
2134
2135 int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used,
2136                            u64 type, u64 chunk_offset, u64 size)
2137 {
2138         struct btrfs_fs_info *fs_info = trans->fs_info;
2139         struct btrfs_block_group *cache;
2140         int ret;
2141
2142         btrfs_set_log_full_commit(trans);
2143
2144         cache = btrfs_create_block_group_cache(fs_info, chunk_offset);
2145         if (!cache)
2146                 return -ENOMEM;
2147
2148         cache->length = size;
2149         set_free_space_tree_thresholds(cache);
2150         cache->used = bytes_used;
2151         cache->flags = type;
2152         cache->last_byte_to_unpin = (u64)-1;
2153         cache->cached = BTRFS_CACHE_FINISHED;
2154         cache->needs_free_space = 1;
2155         ret = exclude_super_stripes(cache);
2156         if (ret) {
2157                 /* We may have excluded something, so call this just in case */
2158                 btrfs_free_excluded_extents(cache);
2159                 btrfs_put_block_group(cache);
2160                 return ret;
2161         }
2162
2163         add_new_free_space(cache, chunk_offset, chunk_offset + size);
2164
2165         btrfs_free_excluded_extents(cache);
2166
2167 #ifdef CONFIG_BTRFS_DEBUG
2168         if (btrfs_should_fragment_free_space(cache)) {
2169                 u64 new_bytes_used = size - bytes_used;
2170
2171                 bytes_used += new_bytes_used >> 1;
2172                 fragment_free_space(cache);
2173         }
2174 #endif
2175         /*
2176          * Ensure the corresponding space_info object is created and
2177          * assigned to our block group. We want our bg to be added to the rbtree
2178          * with its ->space_info set.
2179          */
2180         cache->space_info = btrfs_find_space_info(fs_info, cache->flags);
2181         ASSERT(cache->space_info);
2182
2183         ret = btrfs_add_block_group_cache(fs_info, cache);
2184         if (ret) {
2185                 btrfs_remove_free_space_cache(cache);
2186                 btrfs_put_block_group(cache);
2187                 return ret;
2188         }
2189
2190         /*
2191          * Now that our block group has its ->space_info set and is inserted in
2192          * the rbtree, update the space info's counters.
2193          */
2194         trace_btrfs_add_block_group(fs_info, cache, 1);
2195         btrfs_update_space_info(fs_info, cache->flags, size, bytes_used,
2196                                 cache->bytes_super, &cache->space_info);
2197         btrfs_update_global_block_rsv(fs_info);
2198
2199         link_block_group(cache);
2200
2201         list_add_tail(&cache->bg_list, &trans->new_bgs);
2202         trans->delayed_ref_updates++;
2203         btrfs_update_delayed_refs_rsv(trans);
2204
2205         set_avail_alloc_bits(fs_info, type);
2206         return 0;
2207 }
2208
2209 /*
2210  * Mark one block group RO, can be called several times for the same block
2211  * group.
2212  *
2213  * @cache:              the destination block group
2214  * @do_chunk_alloc:     whether need to do chunk pre-allocation, this is to
2215  *                      ensure we still have some free space after marking this
2216  *                      block group RO.
2217  */
2218 int btrfs_inc_block_group_ro(struct btrfs_block_group *cache,
2219                              bool do_chunk_alloc)
2220 {
2221         struct btrfs_fs_info *fs_info = cache->fs_info;
2222         struct btrfs_trans_handle *trans;
2223         u64 alloc_flags;
2224         int ret;
2225
2226 again:
2227         trans = btrfs_join_transaction(fs_info->extent_root);
2228         if (IS_ERR(trans))
2229                 return PTR_ERR(trans);
2230
2231         /*
2232          * we're not allowed to set block groups readonly after the dirty
2233          * block groups cache has started writing.  If it already started,
2234          * back off and let this transaction commit
2235          */
2236         mutex_lock(&fs_info->ro_block_group_mutex);
2237         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
2238                 u64 transid = trans->transid;
2239
2240                 mutex_unlock(&fs_info->ro_block_group_mutex);
2241                 btrfs_end_transaction(trans);
2242
2243                 ret = btrfs_wait_for_commit(fs_info, transid);
2244                 if (ret)
2245                         return ret;
2246                 goto again;
2247         }
2248
2249         if (do_chunk_alloc) {
2250                 /*
2251                  * If we are changing raid levels, try to allocate a
2252                  * corresponding block group with the new raid level.
2253                  */
2254                 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2255                 if (alloc_flags != cache->flags) {
2256                         ret = btrfs_chunk_alloc(trans, alloc_flags,
2257                                                 CHUNK_ALLOC_FORCE);
2258                         /*
2259                          * ENOSPC is allowed here, we may have enough space
2260                          * already allocated at the new raid level to carry on
2261                          */
2262                         if (ret == -ENOSPC)
2263                                 ret = 0;
2264                         if (ret < 0)
2265                                 goto out;
2266                 }
2267         }
2268
2269         ret = inc_block_group_ro(cache, 0);
2270         if (!do_chunk_alloc)
2271                 goto unlock_out;
2272         if (!ret)
2273                 goto out;
2274         alloc_flags = btrfs_get_alloc_profile(fs_info, cache->space_info->flags);
2275         ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
2276         if (ret < 0)
2277                 goto out;
2278         ret = inc_block_group_ro(cache, 0);
2279 out:
2280         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
2281                 alloc_flags = btrfs_get_alloc_profile(fs_info, cache->flags);
2282                 mutex_lock(&fs_info->chunk_mutex);
2283                 check_system_chunk(trans, alloc_flags);
2284                 mutex_unlock(&fs_info->chunk_mutex);
2285         }
2286 unlock_out:
2287         mutex_unlock(&fs_info->ro_block_group_mutex);
2288
2289         btrfs_end_transaction(trans);
2290         return ret;
2291 }
2292
2293 void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
2294 {
2295         struct btrfs_space_info *sinfo = cache->space_info;
2296         u64 num_bytes;
2297
2298         BUG_ON(!cache->ro);
2299
2300         spin_lock(&sinfo->lock);
2301         spin_lock(&cache->lock);
2302         if (!--cache->ro) {
2303                 num_bytes = cache->length - cache->reserved -
2304                             cache->pinned - cache->bytes_super - cache->used;
2305                 sinfo->bytes_readonly -= num_bytes;
2306                 list_del_init(&cache->ro_list);
2307         }
2308         spin_unlock(&cache->lock);
2309         spin_unlock(&sinfo->lock);
2310 }
2311
2312 static int update_block_group_item(struct btrfs_trans_handle *trans,
2313                                    struct btrfs_path *path,
2314                                    struct btrfs_block_group *cache)
2315 {
2316         struct btrfs_fs_info *fs_info = trans->fs_info;
2317         int ret;
2318         struct btrfs_root *root = fs_info->extent_root;
2319         unsigned long bi;
2320         struct extent_buffer *leaf;
2321         struct btrfs_block_group_item bgi;
2322         struct btrfs_key key;
2323
2324         key.objectid = cache->start;
2325         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2326         key.offset = cache->length;
2327
2328         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2329         if (ret) {
2330                 if (ret > 0)
2331                         ret = -ENOENT;
2332                 goto fail;
2333         }
2334
2335         leaf = path->nodes[0];
2336         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
2337         btrfs_set_stack_block_group_used(&bgi, cache->used);
2338         btrfs_set_stack_block_group_chunk_objectid(&bgi,
2339                         BTRFS_FIRST_CHUNK_TREE_OBJECTID);
2340         btrfs_set_stack_block_group_flags(&bgi, cache->flags);
2341         write_extent_buffer(leaf, &bgi, bi, sizeof(bgi));
2342         btrfs_mark_buffer_dirty(leaf);
2343 fail:
2344         btrfs_release_path(path);
2345         return ret;
2346
2347 }
2348
2349 static int cache_save_setup(struct btrfs_block_group *block_group,
2350                             struct btrfs_trans_handle *trans,
2351                             struct btrfs_path *path)
2352 {
2353         struct btrfs_fs_info *fs_info = block_group->fs_info;
2354         struct btrfs_root *root = fs_info->tree_root;
2355         struct inode *inode = NULL;
2356         struct extent_changeset *data_reserved = NULL;
2357         u64 alloc_hint = 0;
2358         int dcs = BTRFS_DC_ERROR;
2359         u64 num_pages = 0;
2360         int retries = 0;
2361         int ret = 0;
2362
2363         /*
2364          * If this block group is smaller than 100 megs don't bother caching the
2365          * block group.
2366          */
2367         if (block_group->length < (100 * SZ_1M)) {
2368                 spin_lock(&block_group->lock);
2369                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
2370                 spin_unlock(&block_group->lock);
2371                 return 0;
2372         }
2373
2374         if (TRANS_ABORTED(trans))
2375                 return 0;
2376 again:
2377         inode = lookup_free_space_inode(block_group, path);
2378         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
2379                 ret = PTR_ERR(inode);
2380                 btrfs_release_path(path);
2381                 goto out;
2382         }
2383
2384         if (IS_ERR(inode)) {
2385                 BUG_ON(retries);
2386                 retries++;
2387
2388                 if (block_group->ro)
2389                         goto out_free;
2390
2391                 ret = create_free_space_inode(trans, block_group, path);
2392                 if (ret)
2393                         goto out_free;
2394                 goto again;
2395         }
2396
2397         /*
2398          * We want to set the generation to 0, that way if anything goes wrong
2399          * from here on out we know not to trust this cache when we load up next
2400          * time.
2401          */
2402         BTRFS_I(inode)->generation = 0;
2403         ret = btrfs_update_inode(trans, root, inode);
2404         if (ret) {
2405                 /*
2406                  * So theoretically we could recover from this, simply set the
2407                  * super cache generation to 0 so we know to invalidate the
2408                  * cache, but then we'd have to keep track of the block groups
2409                  * that fail this way so we know we _have_ to reset this cache
2410                  * before the next commit or risk reading stale cache.  So to
2411                  * limit our exposure to horrible edge cases lets just abort the
2412                  * transaction, this only happens in really bad situations
2413                  * anyway.
2414                  */
2415                 btrfs_abort_transaction(trans, ret);
2416                 goto out_put;
2417         }
2418         WARN_ON(ret);
2419
2420         /* We've already setup this transaction, go ahead and exit */
2421         if (block_group->cache_generation == trans->transid &&
2422             i_size_read(inode)) {
2423                 dcs = BTRFS_DC_SETUP;
2424                 goto out_put;
2425         }
2426
2427         if (i_size_read(inode) > 0) {
2428                 ret = btrfs_check_trunc_cache_free_space(fs_info,
2429                                         &fs_info->global_block_rsv);
2430                 if (ret)
2431                         goto out_put;
2432
2433                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
2434                 if (ret)
2435                         goto out_put;
2436         }
2437
2438         spin_lock(&block_group->lock);
2439         if (block_group->cached != BTRFS_CACHE_FINISHED ||
2440             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
2441                 /*
2442                  * don't bother trying to write stuff out _if_
2443                  * a) we're not cached,
2444                  * b) we're with nospace_cache mount option,
2445                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
2446                  */
2447                 dcs = BTRFS_DC_WRITTEN;
2448                 spin_unlock(&block_group->lock);
2449                 goto out_put;
2450         }
2451         spin_unlock(&block_group->lock);
2452
2453         /*
2454          * We hit an ENOSPC when setting up the cache in this transaction, just
2455          * skip doing the setup, we've already cleared the cache so we're safe.
2456          */
2457         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
2458                 ret = -ENOSPC;
2459                 goto out_put;
2460         }
2461
2462         /*
2463          * Try to preallocate enough space based on how big the block group is.
2464          * Keep in mind this has to include any pinned space which could end up
2465          * taking up quite a bit since it's not folded into the other space
2466          * cache.
2467          */
2468         num_pages = div_u64(block_group->length, SZ_256M);
2469         if (!num_pages)
2470                 num_pages = 1;
2471
2472         num_pages *= 16;
2473         num_pages *= PAGE_SIZE;
2474
2475         ret = btrfs_check_data_free_space(BTRFS_I(inode), &data_reserved, 0,
2476                                           num_pages);
2477         if (ret)
2478                 goto out_put;
2479
2480         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
2481                                               num_pages, num_pages,
2482                                               &alloc_hint);
2483         /*
2484          * Our cache requires contiguous chunks so that we don't modify a bunch
2485          * of metadata or split extents when writing the cache out, which means
2486          * we can enospc if we are heavily fragmented in addition to just normal
2487          * out of space conditions.  So if we hit this just skip setting up any
2488          * other block groups for this transaction, maybe we'll unpin enough
2489          * space the next time around.
2490          */
2491         if (!ret)
2492                 dcs = BTRFS_DC_SETUP;
2493         else if (ret == -ENOSPC)
2494                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
2495
2496 out_put:
2497         iput(inode);
2498 out_free:
2499         btrfs_release_path(path);
2500 out:
2501         spin_lock(&block_group->lock);
2502         if (!ret && dcs == BTRFS_DC_SETUP)
2503                 block_group->cache_generation = trans->transid;
2504         block_group->disk_cache_state = dcs;
2505         spin_unlock(&block_group->lock);
2506
2507         extent_changeset_free(data_reserved);
2508         return ret;
2509 }
2510
2511 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans)
2512 {
2513         struct btrfs_fs_info *fs_info = trans->fs_info;
2514         struct btrfs_block_group *cache, *tmp;
2515         struct btrfs_transaction *cur_trans = trans->transaction;
2516         struct btrfs_path *path;
2517
2518         if (list_empty(&cur_trans->dirty_bgs) ||
2519             !btrfs_test_opt(fs_info, SPACE_CACHE))
2520                 return 0;
2521
2522         path = btrfs_alloc_path();
2523         if (!path)
2524                 return -ENOMEM;
2525
2526         /* Could add new block groups, use _safe just in case */
2527         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
2528                                  dirty_list) {
2529                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
2530                         cache_save_setup(cache, trans, path);
2531         }
2532
2533         btrfs_free_path(path);
2534         return 0;
2535 }
2536
2537 /*
2538  * Transaction commit does final block group cache writeback during a critical
2539  * section where nothing is allowed to change the FS.  This is required in
2540  * order for the cache to actually match the block group, but can introduce a
2541  * lot of latency into the commit.
2542  *
2543  * So, btrfs_start_dirty_block_groups is here to kick off block group cache IO.
2544  * There's a chance we'll have to redo some of it if the block group changes
2545  * again during the commit, but it greatly reduces the commit latency by
2546  * getting rid of the easy block groups while we're still allowing others to
2547  * join the commit.
2548  */
2549 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans)
2550 {
2551         struct btrfs_fs_info *fs_info = trans->fs_info;
2552         struct btrfs_block_group *cache;
2553         struct btrfs_transaction *cur_trans = trans->transaction;
2554         int ret = 0;
2555         int should_put;
2556         struct btrfs_path *path = NULL;
2557         LIST_HEAD(dirty);
2558         struct list_head *io = &cur_trans->io_bgs;
2559         int num_started = 0;
2560         int loops = 0;
2561
2562         spin_lock(&cur_trans->dirty_bgs_lock);
2563         if (list_empty(&cur_trans->dirty_bgs)) {
2564                 spin_unlock(&cur_trans->dirty_bgs_lock);
2565                 return 0;
2566         }
2567         list_splice_init(&cur_trans->dirty_bgs, &dirty);
2568         spin_unlock(&cur_trans->dirty_bgs_lock);
2569
2570 again:
2571         /* Make sure all the block groups on our dirty list actually exist */
2572         btrfs_create_pending_block_groups(trans);
2573
2574         if (!path) {
2575                 path = btrfs_alloc_path();
2576                 if (!path)
2577                         return -ENOMEM;
2578         }
2579
2580         /*
2581          * cache_write_mutex is here only to save us from balance or automatic
2582          * removal of empty block groups deleting this block group while we are
2583          * writing out the cache
2584          */
2585         mutex_lock(&trans->transaction->cache_write_mutex);
2586         while (!list_empty(&dirty)) {
2587                 bool drop_reserve = true;
2588
2589                 cache = list_first_entry(&dirty, struct btrfs_block_group,
2590                                          dirty_list);
2591                 /*
2592                  * This can happen if something re-dirties a block group that
2593                  * is already under IO.  Just wait for it to finish and then do
2594                  * it all again
2595                  */
2596                 if (!list_empty(&cache->io_list)) {
2597                         list_del_init(&cache->io_list);
2598                         btrfs_wait_cache_io(trans, cache, path);
2599                         btrfs_put_block_group(cache);
2600                 }
2601
2602
2603                 /*
2604                  * btrfs_wait_cache_io uses the cache->dirty_list to decide if
2605                  * it should update the cache_state.  Don't delete until after
2606                  * we wait.
2607                  *
2608                  * Since we're not running in the commit critical section
2609                  * we need the dirty_bgs_lock to protect from update_block_group
2610                  */
2611                 spin_lock(&cur_trans->dirty_bgs_lock);
2612                 list_del_init(&cache->dirty_list);
2613                 spin_unlock(&cur_trans->dirty_bgs_lock);
2614
2615                 should_put = 1;
2616
2617                 cache_save_setup(cache, trans, path);
2618
2619                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
2620                         cache->io_ctl.inode = NULL;
2621                         ret = btrfs_write_out_cache(trans, cache, path);
2622                         if (ret == 0 && cache->io_ctl.inode) {
2623                                 num_started++;
2624                                 should_put = 0;
2625
2626                                 /*
2627                                  * The cache_write_mutex is protecting the
2628                                  * io_list, also refer to the definition of
2629                                  * btrfs_transaction::io_bgs for more details
2630                                  */
2631                                 list_add_tail(&cache->io_list, io);
2632                         } else {
2633                                 /*
2634                                  * If we failed to write the cache, the
2635                                  * generation will be bad and life goes on
2636                                  */
2637                                 ret = 0;
2638                         }
2639                 }
2640                 if (!ret) {
2641                         ret = update_block_group_item(trans, path, cache);
2642                         /*
2643                          * Our block group might still be attached to the list
2644                          * of new block groups in the transaction handle of some
2645                          * other task (struct btrfs_trans_handle->new_bgs). This
2646                          * means its block group item isn't yet in the extent
2647                          * tree. If this happens ignore the error, as we will
2648                          * try again later in the critical section of the
2649                          * transaction commit.
2650                          */
2651                         if (ret == -ENOENT) {
2652                                 ret = 0;
2653                                 spin_lock(&cur_trans->dirty_bgs_lock);
2654                                 if (list_empty(&cache->dirty_list)) {
2655                                         list_add_tail(&cache->dirty_list,
2656                                                       &cur_trans->dirty_bgs);
2657                                         btrfs_get_block_group(cache);
2658                                         drop_reserve = false;
2659                                 }
2660                                 spin_unlock(&cur_trans->dirty_bgs_lock);
2661                         } else if (ret) {
2662                                 btrfs_abort_transaction(trans, ret);
2663                         }
2664                 }
2665
2666                 /* If it's not on the io list, we need to put the block group */
2667                 if (should_put)
2668                         btrfs_put_block_group(cache);
2669                 if (drop_reserve)
2670                         btrfs_delayed_refs_rsv_release(fs_info, 1);
2671
2672                 if (ret)
2673                         break;
2674
2675                 /*
2676                  * Avoid blocking other tasks for too long. It might even save
2677                  * us from writing caches for block groups that are going to be
2678                  * removed.
2679                  */
2680                 mutex_unlock(&trans->transaction->cache_write_mutex);
2681                 mutex_lock(&trans->transaction->cache_write_mutex);
2682         }
2683         mutex_unlock(&trans->transaction->cache_write_mutex);
2684
2685         /*
2686          * Go through delayed refs for all the stuff we've just kicked off
2687          * and then loop back (just once)
2688          */
2689         ret = btrfs_run_delayed_refs(trans, 0);
2690         if (!ret && loops == 0) {
2691                 loops++;
2692                 spin_lock(&cur_trans->dirty_bgs_lock);
2693                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
2694                 /*
2695                  * dirty_bgs_lock protects us from concurrent block group
2696                  * deletes too (not just cache_write_mutex).
2697                  */
2698                 if (!list_empty(&dirty)) {
2699                         spin_unlock(&cur_trans->dirty_bgs_lock);
2700                         goto again;
2701                 }
2702                 spin_unlock(&cur_trans->dirty_bgs_lock);
2703         } else if (ret < 0) {
2704                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
2705         }
2706
2707         btrfs_free_path(path);
2708         return ret;
2709 }
2710
2711 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans)
2712 {
2713         struct btrfs_fs_info *fs_info = trans->fs_info;
2714         struct btrfs_block_group *cache;
2715         struct btrfs_transaction *cur_trans = trans->transaction;
2716         int ret = 0;
2717         int should_put;
2718         struct btrfs_path *path;
2719         struct list_head *io = &cur_trans->io_bgs;
2720         int num_started = 0;
2721
2722         path = btrfs_alloc_path();
2723         if (!path)
2724                 return -ENOMEM;
2725
2726         /*
2727          * Even though we are in the critical section of the transaction commit,
2728          * we can still have concurrent tasks adding elements to this
2729          * transaction's list of dirty block groups. These tasks correspond to
2730          * endio free space workers started when writeback finishes for a
2731          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
2732          * allocate new block groups as a result of COWing nodes of the root
2733          * tree when updating the free space inode. The writeback for the space
2734          * caches is triggered by an earlier call to
2735          * btrfs_start_dirty_block_groups() and iterations of the following
2736          * loop.
2737          * Also we want to do the cache_save_setup first and then run the
2738          * delayed refs to make sure we have the best chance at doing this all
2739          * in one shot.
2740          */
2741         spin_lock(&cur_trans->dirty_bgs_lock);
2742         while (!list_empty(&cur_trans->dirty_bgs)) {
2743                 cache = list_first_entry(&cur_trans->dirty_bgs,
2744                                          struct btrfs_block_group,
2745                                          dirty_list);
2746
2747                 /*
2748                  * This can happen if cache_save_setup re-dirties a block group
2749                  * that is already under IO.  Just wait for it to finish and
2750                  * then do it all again
2751                  */
2752                 if (!list_empty(&cache->io_list)) {
2753                         spin_unlock(&cur_trans->dirty_bgs_lock);
2754                         list_del_init(&cache->io_list);
2755                         btrfs_wait_cache_io(trans, cache, path);
2756                         btrfs_put_block_group(cache);
2757                         spin_lock(&cur_trans->dirty_bgs_lock);
2758                 }
2759
2760                 /*
2761                  * Don't remove from the dirty list until after we've waited on
2762                  * any pending IO
2763                  */
2764                 list_del_init(&cache->dirty_list);
2765                 spin_unlock(&cur_trans->dirty_bgs_lock);
2766                 should_put = 1;
2767
2768                 cache_save_setup(cache, trans, path);
2769
2770                 if (!ret)
2771                         ret = btrfs_run_delayed_refs(trans,
2772                                                      (unsigned long) -1);
2773
2774                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
2775                         cache->io_ctl.inode = NULL;
2776                         ret = btrfs_write_out_cache(trans, cache, path);
2777                         if (ret == 0 && cache->io_ctl.inode) {
2778                                 num_started++;
2779                                 should_put = 0;
2780                                 list_add_tail(&cache->io_list, io);
2781                         } else {
2782                                 /*
2783                                  * If we failed to write the cache, the
2784                                  * generation will be bad and life goes on
2785                                  */
2786                                 ret = 0;
2787                         }
2788                 }
2789                 if (!ret) {
2790                         ret = update_block_group_item(trans, path, cache);
2791                         /*
2792                          * One of the free space endio workers might have
2793                          * created a new block group while updating a free space
2794                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
2795                          * and hasn't released its transaction handle yet, in
2796                          * which case the new block group is still attached to
2797                          * its transaction handle and its creation has not
2798                          * finished yet (no block group item in the extent tree
2799                          * yet, etc). If this is the case, wait for all free
2800                          * space endio workers to finish and retry. This is a
2801                          * very rare case so no need for a more efficient and
2802                          * complex approach.
2803                          */
2804                         if (ret == -ENOENT) {
2805                                 wait_event(cur_trans->writer_wait,
2806                                    atomic_read(&cur_trans->num_writers) == 1);
2807                                 ret = update_block_group_item(trans, path, cache);
2808                         }
2809                         if (ret)
2810                                 btrfs_abort_transaction(trans, ret);
2811                 }
2812
2813                 /* If its not on the io list, we need to put the block group */
2814                 if (should_put)
2815                         btrfs_put_block_group(cache);
2816                 btrfs_delayed_refs_rsv_release(fs_info, 1);
2817                 spin_lock(&cur_trans->dirty_bgs_lock);
2818         }
2819         spin_unlock(&cur_trans->dirty_bgs_lock);
2820
2821         /*
2822          * Refer to the definition of io_bgs member for details why it's safe
2823          * to use it without any locking
2824          */
2825         while (!list_empty(io)) {
2826                 cache = list_first_entry(io, struct btrfs_block_group,
2827                                          io_list);
2828                 list_del_init(&cache->io_list);
2829                 btrfs_wait_cache_io(trans, cache, path);
2830                 btrfs_put_block_group(cache);
2831         }
2832
2833         btrfs_free_path(path);
2834         return ret;
2835 }
2836
2837 int btrfs_update_block_group(struct btrfs_trans_handle *trans,
2838                              u64 bytenr, u64 num_bytes, int alloc)
2839 {
2840         struct btrfs_fs_info *info = trans->fs_info;
2841         struct btrfs_block_group *cache = NULL;
2842         u64 total = num_bytes;
2843         u64 old_val;
2844         u64 byte_in_group;
2845         int factor;
2846         int ret = 0;
2847
2848         /* Block accounting for super block */
2849         spin_lock(&info->delalloc_root_lock);
2850         old_val = btrfs_super_bytes_used(info->super_copy);
2851         if (alloc)
2852                 old_val += num_bytes;
2853         else
2854                 old_val -= num_bytes;
2855         btrfs_set_super_bytes_used(info->super_copy, old_val);
2856         spin_unlock(&info->delalloc_root_lock);
2857
2858         while (total) {
2859                 cache = btrfs_lookup_block_group(info, bytenr);
2860                 if (!cache) {
2861                         ret = -ENOENT;
2862                         break;
2863                 }
2864                 factor = btrfs_bg_type_to_factor(cache->flags);
2865
2866                 /*
2867                  * If this block group has free space cache written out, we
2868                  * need to make sure to load it if we are removing space.  This
2869                  * is because we need the unpinning stage to actually add the
2870                  * space back to the block group, otherwise we will leak space.
2871                  */
2872                 if (!alloc && !btrfs_block_group_done(cache))
2873                         btrfs_cache_block_group(cache, 1);
2874
2875                 byte_in_group = bytenr - cache->start;
2876                 WARN_ON(byte_in_group > cache->length);
2877
2878                 spin_lock(&cache->space_info->lock);
2879                 spin_lock(&cache->lock);
2880
2881                 if (btrfs_test_opt(info, SPACE_CACHE) &&
2882                     cache->disk_cache_state < BTRFS_DC_CLEAR)
2883                         cache->disk_cache_state = BTRFS_DC_CLEAR;
2884
2885                 old_val = cache->used;
2886                 num_bytes = min(total, cache->length - byte_in_group);
2887                 if (alloc) {
2888                         old_val += num_bytes;
2889                         cache->used = old_val;
2890                         cache->reserved -= num_bytes;
2891                         cache->space_info->bytes_reserved -= num_bytes;
2892                         cache->space_info->bytes_used += num_bytes;
2893                         cache->space_info->disk_used += num_bytes * factor;
2894                         spin_unlock(&cache->lock);
2895                         spin_unlock(&cache->space_info->lock);
2896                 } else {
2897                         old_val -= num_bytes;
2898                         cache->used = old_val;
2899                         cache->pinned += num_bytes;
2900                         btrfs_space_info_update_bytes_pinned(info,
2901                                         cache->space_info, num_bytes);
2902                         cache->space_info->bytes_used -= num_bytes;
2903                         cache->space_info->disk_used -= num_bytes * factor;
2904                         spin_unlock(&cache->lock);
2905                         spin_unlock(&cache->space_info->lock);
2906
2907                         percpu_counter_add_batch(
2908                                         &cache->space_info->total_bytes_pinned,
2909                                         num_bytes,
2910                                         BTRFS_TOTAL_BYTES_PINNED_BATCH);
2911                         set_extent_dirty(&trans->transaction->pinned_extents,
2912                                          bytenr, bytenr + num_bytes - 1,
2913                                          GFP_NOFS | __GFP_NOFAIL);
2914                 }
2915
2916                 spin_lock(&trans->transaction->dirty_bgs_lock);
2917                 if (list_empty(&cache->dirty_list)) {
2918                         list_add_tail(&cache->dirty_list,
2919                                       &trans->transaction->dirty_bgs);
2920                         trans->delayed_ref_updates++;
2921                         btrfs_get_block_group(cache);
2922                 }
2923                 spin_unlock(&trans->transaction->dirty_bgs_lock);
2924
2925                 /*
2926                  * No longer have used bytes in this block group, queue it for
2927                  * deletion. We do this after adding the block group to the
2928                  * dirty list to avoid races between cleaner kthread and space
2929                  * cache writeout.
2930                  */
2931                 if (!alloc && old_val == 0) {
2932                         if (!btrfs_test_opt(info, DISCARD_ASYNC))
2933                                 btrfs_mark_bg_unused(cache);
2934                 }
2935
2936                 btrfs_put_block_group(cache);
2937                 total -= num_bytes;
2938                 bytenr += num_bytes;
2939         }
2940
2941         /* Modified block groups are accounted for in the delayed_refs_rsv. */
2942         btrfs_update_delayed_refs_rsv(trans);
2943         return ret;
2944 }
2945
2946 /**
2947  * btrfs_add_reserved_bytes - update the block_group and space info counters
2948  * @cache:      The cache we are manipulating
2949  * @ram_bytes:  The number of bytes of file content, and will be same to
2950  *              @num_bytes except for the compress path.
2951  * @num_bytes:  The number of bytes in question
2952  * @delalloc:   The blocks are allocated for the delalloc write
2953  *
2954  * This is called by the allocator when it reserves space. If this is a
2955  * reservation and the block group has become read only we cannot make the
2956  * reservation and return -EAGAIN, otherwise this function always succeeds.
2957  */
2958 int btrfs_add_reserved_bytes(struct btrfs_block_group *cache,
2959                              u64 ram_bytes, u64 num_bytes, int delalloc)
2960 {
2961         struct btrfs_space_info *space_info = cache->space_info;
2962         int ret = 0;
2963
2964         spin_lock(&space_info->lock);
2965         spin_lock(&cache->lock);
2966         if (cache->ro) {
2967                 ret = -EAGAIN;
2968         } else {
2969                 cache->reserved += num_bytes;
2970                 space_info->bytes_reserved += num_bytes;
2971                 trace_btrfs_space_reservation(cache->fs_info, "space_info",
2972                                               space_info->flags, num_bytes, 1);
2973                 btrfs_space_info_update_bytes_may_use(cache->fs_info,
2974                                                       space_info, -ram_bytes);
2975                 if (delalloc)
2976                         cache->delalloc_bytes += num_bytes;
2977
2978                 /*
2979                  * Compression can use less space than we reserved, so wake
2980                  * tickets if that happens
2981                  */
2982                 if (num_bytes < ram_bytes)
2983                         btrfs_try_granting_tickets(cache->fs_info, space_info);
2984         }
2985         spin_unlock(&cache->lock);
2986         spin_unlock(&space_info->lock);
2987         return ret;
2988 }
2989
2990 /**
2991  * btrfs_free_reserved_bytes - update the block_group and space info counters
2992  * @cache:      The cache we are manipulating
2993  * @num_bytes:  The number of bytes in question
2994  * @delalloc:   The blocks are allocated for the delalloc write
2995  *
2996  * This is called by somebody who is freeing space that was never actually used
2997  * on disk.  For example if you reserve some space for a new leaf in transaction
2998  * A and before transaction A commits you free that leaf, you call this with
2999  * reserve set to 0 in order to clear the reservation.
3000  */
3001 void btrfs_free_reserved_bytes(struct btrfs_block_group *cache,
3002                                u64 num_bytes, int delalloc)
3003 {
3004         struct btrfs_space_info *space_info = cache->space_info;
3005
3006         spin_lock(&space_info->lock);
3007         spin_lock(&cache->lock);
3008         if (cache->ro)
3009                 space_info->bytes_readonly += num_bytes;
3010         cache->reserved -= num_bytes;
3011         space_info->bytes_reserved -= num_bytes;
3012         space_info->max_extent_size = 0;
3013
3014         if (delalloc)
3015                 cache->delalloc_bytes -= num_bytes;
3016         spin_unlock(&cache->lock);
3017
3018         btrfs_try_granting_tickets(cache->fs_info, space_info);
3019         spin_unlock(&space_info->lock);
3020 }
3021
3022 static void force_metadata_allocation(struct btrfs_fs_info *info)
3023 {
3024         struct list_head *head = &info->space_info;
3025         struct btrfs_space_info *found;
3026
3027         list_for_each_entry(found, head, list) {
3028                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3029                         found->force_alloc = CHUNK_ALLOC_FORCE;
3030         }
3031 }
3032
3033 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
3034                               struct btrfs_space_info *sinfo, int force)
3035 {
3036         u64 bytes_used = btrfs_space_info_used(sinfo, false);
3037         u64 thresh;
3038
3039         if (force == CHUNK_ALLOC_FORCE)
3040                 return 1;
3041
3042         /*
3043          * in limited mode, we want to have some free space up to
3044          * about 1% of the FS size.
3045          */
3046         if (force == CHUNK_ALLOC_LIMITED) {
3047                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
3048                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
3049
3050                 if (sinfo->total_bytes - bytes_used < thresh)
3051                         return 1;
3052         }
3053
3054         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
3055                 return 0;
3056         return 1;
3057 }
3058
3059 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans, u64 type)
3060 {
3061         u64 alloc_flags = btrfs_get_alloc_profile(trans->fs_info, type);
3062
3063         return btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);
3064 }
3065
3066 /*
3067  * If force is CHUNK_ALLOC_FORCE:
3068  *    - return 1 if it successfully allocates a chunk,
3069  *    - return errors including -ENOSPC otherwise.
3070  * If force is NOT CHUNK_ALLOC_FORCE:
3071  *    - return 0 if it doesn't need to allocate a new chunk,
3072  *    - return 1 if it successfully allocates a chunk,
3073  *    - return errors including -ENOSPC otherwise.
3074  */
3075 int btrfs_chunk_alloc(struct btrfs_trans_handle *trans, u64 flags,
3076                       enum btrfs_chunk_alloc_enum force)
3077 {
3078         struct btrfs_fs_info *fs_info = trans->fs_info;
3079         struct btrfs_space_info *space_info;
3080         bool wait_for_alloc = false;
3081         bool should_alloc = false;
3082         int ret = 0;
3083
3084         /* Don't re-enter if we're already allocating a chunk */
3085         if (trans->allocating_chunk)
3086                 return -ENOSPC;
3087
3088         space_info = btrfs_find_space_info(fs_info, flags);
3089         ASSERT(space_info);
3090
3091         do {
3092                 spin_lock(&space_info->lock);
3093                 if (force < space_info->force_alloc)
3094                         force = space_info->force_alloc;
3095                 should_alloc = should_alloc_chunk(fs_info, space_info, force);
3096                 if (space_info->full) {
3097                         /* No more free physical space */
3098                         if (should_alloc)
3099                                 ret = -ENOSPC;
3100                         else
3101                                 ret = 0;
3102                         spin_unlock(&space_info->lock);
3103                         return ret;
3104                 } else if (!should_alloc) {
3105                         spin_unlock(&space_info->lock);
3106                         return 0;
3107                 } else if (space_info->chunk_alloc) {
3108                         /*
3109                          * Someone is already allocating, so we need to block
3110                          * until this someone is finished and then loop to
3111                          * recheck if we should continue with our allocation
3112                          * attempt.
3113                          */
3114                         wait_for_alloc = true;
3115                         spin_unlock(&space_info->lock);
3116                         mutex_lock(&fs_info->chunk_mutex);
3117                         mutex_unlock(&fs_info->chunk_mutex);
3118                 } else {
3119                         /* Proceed with allocation */
3120                         space_info->chunk_alloc = 1;
3121                         wait_for_alloc = false;
3122                         spin_unlock(&space_info->lock);
3123                 }
3124
3125                 cond_resched();
3126         } while (wait_for_alloc);
3127
3128         mutex_lock(&fs_info->chunk_mutex);
3129         trans->allocating_chunk = true;
3130
3131         /*
3132          * If we have mixed data/metadata chunks we want to make sure we keep
3133          * allocating mixed chunks instead of individual chunks.
3134          */
3135         if (btrfs_mixed_space_info(space_info))
3136                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3137
3138         /*
3139          * if we're doing a data chunk, go ahead and make sure that
3140          * we keep a reasonable number of metadata chunks allocated in the
3141          * FS as well.
3142          */
3143         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3144                 fs_info->data_chunk_allocations++;
3145                 if (!(fs_info->data_chunk_allocations %
3146                       fs_info->metadata_ratio))
3147                         force_metadata_allocation(fs_info);
3148         }
3149
3150         /*
3151          * Check if we have enough space in SYSTEM chunk because we may need
3152          * to update devices.
3153          */
3154         check_system_chunk(trans, flags);
3155
3156         ret = btrfs_alloc_chunk(trans, flags);
3157         trans->allocating_chunk = false;
3158
3159         spin_lock(&space_info->lock);
3160         if (ret < 0) {
3161                 if (ret == -ENOSPC)
3162                         space_info->full = 1;
3163                 else
3164                         goto out;
3165         } else {
3166                 ret = 1;
3167                 space_info->max_extent_size = 0;
3168         }
3169
3170         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3171 out:
3172         space_info->chunk_alloc = 0;
3173         spin_unlock(&space_info->lock);
3174         mutex_unlock(&fs_info->chunk_mutex);
3175         /*
3176          * When we allocate a new chunk we reserve space in the chunk block
3177          * reserve to make sure we can COW nodes/leafs in the chunk tree or
3178          * add new nodes/leafs to it if we end up needing to do it when
3179          * inserting the chunk item and updating device items as part of the
3180          * second phase of chunk allocation, performed by
3181          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
3182          * large number of new block groups to create in our transaction
3183          * handle's new_bgs list to avoid exhausting the chunk block reserve
3184          * in extreme cases - like having a single transaction create many new
3185          * block groups when starting to write out the free space caches of all
3186          * the block groups that were made dirty during the lifetime of the
3187          * transaction.
3188          */
3189         if (trans->chunk_bytes_reserved >= (u64)SZ_2M)
3190                 btrfs_create_pending_block_groups(trans);
3191
3192         return ret;
3193 }
3194
3195 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
3196 {
3197         u64 num_dev;
3198
3199         num_dev = btrfs_raid_array[btrfs_bg_flags_to_raid_index(type)].devs_max;
3200         if (!num_dev)
3201                 num_dev = fs_info->fs_devices->rw_devices;
3202
3203         return num_dev;
3204 }
3205
3206 /*
3207  * Reserve space in the system space for allocating or removing a chunk
3208  */
3209 void check_system_chunk(struct btrfs_trans_handle *trans, u64 type)
3210 {
3211         struct btrfs_fs_info *fs_info = trans->fs_info;
3212         struct btrfs_space_info *info;
3213         u64 left;
3214         u64 thresh;
3215         int ret = 0;
3216         u64 num_devs;
3217
3218         /*
3219          * Needed because we can end up allocating a system chunk and for an
3220          * atomic and race free space reservation in the chunk block reserve.
3221          */
3222         lockdep_assert_held(&fs_info->chunk_mutex);
3223
3224         info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3225         spin_lock(&info->lock);
3226         left = info->total_bytes - btrfs_space_info_used(info, true);
3227         spin_unlock(&info->lock);
3228
3229         num_devs = get_profile_num_devs(fs_info, type);
3230
3231         /* num_devs device items to update and 1 chunk item to add or remove */
3232         thresh = btrfs_calc_metadata_size(fs_info, num_devs) +
3233                 btrfs_calc_insert_metadata_size(fs_info, 1);
3234
3235         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
3236                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
3237                            left, thresh, type);
3238                 btrfs_dump_space_info(fs_info, info, 0, 0);
3239         }
3240
3241         if (left < thresh) {
3242                 u64 flags = btrfs_system_alloc_profile(fs_info);
3243
3244                 /*
3245                  * Ignore failure to create system chunk. We might end up not
3246                  * needing it, as we might not need to COW all nodes/leafs from
3247                  * the paths we visit in the chunk tree (they were already COWed
3248                  * or created in the current transaction for example).
3249                  */
3250                 ret = btrfs_alloc_chunk(trans, flags);
3251         }
3252
3253         if (!ret) {
3254                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
3255                                           &fs_info->chunk_block_rsv,
3256                                           thresh, BTRFS_RESERVE_NO_FLUSH);
3257                 if (!ret)
3258                         trans->chunk_bytes_reserved += thresh;
3259         }
3260 }
3261
3262 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
3263 {
3264         struct btrfs_block_group *block_group;
3265         u64 last = 0;
3266
3267         while (1) {
3268                 struct inode *inode;
3269
3270                 block_group = btrfs_lookup_first_block_group(info, last);
3271                 while (block_group) {
3272                         btrfs_wait_block_group_cache_done(block_group);
3273                         spin_lock(&block_group->lock);
3274                         if (block_group->iref)
3275                                 break;
3276                         spin_unlock(&block_group->lock);
3277                         block_group = btrfs_next_block_group(block_group);
3278                 }
3279                 if (!block_group) {
3280                         if (last == 0)
3281                                 break;
3282                         last = 0;
3283                         continue;
3284                 }
3285
3286                 inode = block_group->inode;
3287                 block_group->iref = 0;
3288                 block_group->inode = NULL;
3289                 spin_unlock(&block_group->lock);
3290                 ASSERT(block_group->io_ctl.inode == NULL);
3291                 iput(inode);
3292                 last = block_group->start + block_group->length;
3293                 btrfs_put_block_group(block_group);
3294         }
3295 }
3296
3297 /*
3298  * Must be called only after stopping all workers, since we could have block
3299  * group caching kthreads running, and therefore they could race with us if we
3300  * freed the block groups before stopping them.
3301  */
3302 int btrfs_free_block_groups(struct btrfs_fs_info *info)
3303 {
3304         struct btrfs_block_group *block_group;
3305         struct btrfs_space_info *space_info;
3306         struct btrfs_caching_control *caching_ctl;
3307         struct rb_node *n;
3308
3309         down_write(&info->commit_root_sem);
3310         while (!list_empty(&info->caching_block_groups)) {
3311                 caching_ctl = list_entry(info->caching_block_groups.next,
3312                                          struct btrfs_caching_control, list);
3313                 list_del(&caching_ctl->list);
3314                 btrfs_put_caching_control(caching_ctl);
3315         }
3316         up_write(&info->commit_root_sem);
3317
3318         spin_lock(&info->unused_bgs_lock);
3319         while (!list_empty(&info->unused_bgs)) {
3320                 block_group = list_first_entry(&info->unused_bgs,
3321                                                struct btrfs_block_group,
3322                                                bg_list);
3323                 list_del_init(&block_group->bg_list);
3324                 btrfs_put_block_group(block_group);
3325         }
3326         spin_unlock(&info->unused_bgs_lock);
3327
3328         spin_lock(&info->block_group_cache_lock);
3329         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
3330                 block_group = rb_entry(n, struct btrfs_block_group,
3331                                        cache_node);
3332                 rb_erase(&block_group->cache_node,
3333                          &info->block_group_cache_tree);
3334                 RB_CLEAR_NODE(&block_group->cache_node);
3335                 spin_unlock(&info->block_group_cache_lock);
3336
3337                 down_write(&block_group->space_info->groups_sem);
3338                 list_del(&block_group->list);
3339                 up_write(&block_group->space_info->groups_sem);
3340
3341                 /*
3342                  * We haven't cached this block group, which means we could
3343                  * possibly have excluded extents on this block group.
3344                  */
3345                 if (block_group->cached == BTRFS_CACHE_NO ||
3346                     block_group->cached == BTRFS_CACHE_ERROR)
3347                         btrfs_free_excluded_extents(block_group);
3348
3349                 btrfs_remove_free_space_cache(block_group);
3350                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
3351                 ASSERT(list_empty(&block_group->dirty_list));
3352                 ASSERT(list_empty(&block_group->io_list));
3353                 ASSERT(list_empty(&block_group->bg_list));
3354                 ASSERT(refcount_read(&block_group->refs) == 1);
3355                 btrfs_put_block_group(block_group);
3356
3357                 spin_lock(&info->block_group_cache_lock);
3358         }
3359         spin_unlock(&info->block_group_cache_lock);
3360
3361         btrfs_release_global_block_rsv(info);
3362
3363         while (!list_empty(&info->space_info)) {
3364                 space_info = list_entry(info->space_info.next,
3365                                         struct btrfs_space_info,
3366                                         list);
3367
3368                 /*
3369                  * Do not hide this behind enospc_debug, this is actually
3370                  * important and indicates a real bug if this happens.
3371                  */
3372                 if (WARN_ON(space_info->bytes_pinned > 0 ||
3373                             space_info->bytes_reserved > 0 ||
3374                             space_info->bytes_may_use > 0))
3375                         btrfs_dump_space_info(info, space_info, 0, 0);
3376                 WARN_ON(space_info->reclaim_size > 0);
3377                 list_del(&space_info->list);
3378                 btrfs_sysfs_remove_space_info(space_info);
3379         }
3380         return 0;
3381 }
3382
3383 void btrfs_freeze_block_group(struct btrfs_block_group *cache)
3384 {
3385         atomic_inc(&cache->frozen);
3386 }
3387
3388 void btrfs_unfreeze_block_group(struct btrfs_block_group *block_group)
3389 {
3390         struct btrfs_fs_info *fs_info = block_group->fs_info;
3391         struct extent_map_tree *em_tree;
3392         struct extent_map *em;
3393         bool cleanup;
3394
3395         spin_lock(&block_group->lock);
3396         cleanup = (atomic_dec_and_test(&block_group->frozen) &&
3397                    block_group->removed);
3398         spin_unlock(&block_group->lock);
3399
3400         if (cleanup) {
3401                 em_tree = &fs_info->mapping_tree;
3402                 write_lock(&em_tree->lock);
3403                 em = lookup_extent_mapping(em_tree, block_group->start,
3404                                            1);
3405                 BUG_ON(!em); /* logic error, can't happen */
3406                 remove_extent_mapping(em_tree, em);
3407                 write_unlock(&em_tree->lock);
3408
3409                 /* once for us and once for the tree */
3410                 free_extent_map(em);
3411                 free_extent_map(em);
3412
3413                 /*
3414                  * We may have left one free space entry and other possible
3415                  * tasks trimming this block group have left 1 entry each one.
3416                  * Free them if any.
3417                  */
3418                 __btrfs_remove_free_space_cache(block_group->free_space_ctl);
3419         }
3420 }