fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include <linux/rcupdate.h>
  24 #include <linux/kthread.h>
  25 #include <linux/slab.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/percpu_counter.h>
  28 #include "hash.h"
  29 #include "tree-log.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "volumes.h"
  33 #include "raid56.h"
  34 #include "locking.h"
  35 #include "free-space-cache.h"
  36 #include "math.h"
  37 #include "sysfs.h"
  38 #include "qgroup.h"
  39
  40 #undef SCRAMBLE_DELAYED_REFS
  41
  42 /*
  43  * control flags for do_chunk_alloc's force field
  44  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  45  * if we really need one.
  46  *
  47  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  48  * if we have very few chunks already allocated.  This is
  49  * used as part of the clustering code to help make sure
  50  * we have a good pool of storage to cluster in, without
  51  * filling the FS with empty chunks
  52  *
  53  * CHUNK_ALLOC_FORCE means it must try to allocate one
  54  *
  55  */
  56 enum {
  57         CHUNK_ALLOC_NO_FORCE = 0,
  58         CHUNK_ALLOC_LIMITED = 1,
  59         CHUNK_ALLOC_FORCE = 2,
  60 };
  61
  62 /*
  63  * Control how reservations are dealt with.
  64  *
  65  * RESERVE_FREE - freeing a reservation.
  66  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  67  *   ENOSPC accounting
  68  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  69  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  70  */
  71 enum {
  72         RESERVE_FREE = 0,
  73         RESERVE_ALLOC = 1,
  74         RESERVE_ALLOC_NO_ACCOUNT = 2,
  75 };
  76
  77 static int update_block_group(struct btrfs_trans_handle *trans,
  78                               struct btrfs_root *root, u64 bytenr,
  79                               u64 num_bytes, int alloc);
  80 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  81                                 struct btrfs_root *root,
  82                                 struct btrfs_delayed_ref_node *node, u64 parent,
  83                                 u64 root_objectid, u64 owner_objectid,
  84                                 u64 owner_offset, int refs_to_drop,
  85                                 struct btrfs_delayed_extent_op *extra_op);
  86 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  87                                     struct extent_buffer *leaf,
  88                                     struct btrfs_extent_item *ei);
  89 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  90                                       struct btrfs_root *root,
  91                                       u64 parent, u64 root_objectid,
  92                                       u64 flags, u64 owner, u64 offset,
  93                                       struct btrfs_key *ins, int ref_mod);
  94 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  95                                      struct btrfs_root *root,
  96                                      u64 parent, u64 root_objectid,
  97                                      u64 flags, struct btrfs_disk_key *key,
  98                                      int level, struct btrfs_key *ins,
  99                                      int no_quota);
 100 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
 101                           struct btrfs_root *extent_root, u64 flags,
 102                           int force);
 103 static int find_next_key(struct btrfs_path *path, int level,
 104                          struct btrfs_key *key);
 105 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 106                             int dump_block_groups);
 107 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 108                                        u64 num_bytes, int reserve,
 109                                        int delalloc);
 110 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 111                                u64 num_bytes);
 112 int btrfs_pin_extent(struct btrfs_root *root,
 113                      u64 bytenr, u64 num_bytes, int reserved);
 114
 115 static noinline int
 116 block_group_cache_done(struct btrfs_block_group_cache *cache)
 117 {
 118         smp_mb();
 119         return cache->cached == BTRFS_CACHE_FINISHED ||
 120                 cache->cached == BTRFS_CACHE_ERROR;
 121 }
 122
 123 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 124 {
 125         return (cache->flags & bits) == bits;
 126 }
 127
 128 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 129 {
 130         atomic_inc(&cache->count);
 131 }
 132
 133 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 134 {
 135         if (atomic_dec_and_test(&cache->count)) {
 136                 WARN_ON(cache->pinned > 0);
 137                 WARN_ON(cache->reserved > 0);
 138                 kfree(cache->free_space_ctl);
 139                 kfree(cache);
 140         }
 141 }
 142
 143 /*
 144  * this adds the block group to the fs_info rb tree for the block group
 145  * cache
 146  */
 147 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 148                                 struct btrfs_block_group_cache *block_group)
 149 {
 150         struct rb_node **p;
 151         struct rb_node *parent = NULL;
 152         struct btrfs_block_group_cache *cache;
 153
 154         spin_lock(&info->block_group_cache_lock);
 155         p = &info->block_group_cache_tree.rb_node;
 156
 157         while (*p) {
 158                 parent = *p;
 159                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 160                                  cache_node);
 161                 if (block_group->key.objectid < cache->key.objectid) {
 162                         p = &(*p)->rb_left;
 163                 } else if (block_group->key.objectid > cache->key.objectid) {
 164                         p = &(*p)->rb_right;
 165                 } else {
 166                         spin_unlock(&info->block_group_cache_lock);
 167                         return -EEXIST;
 168                 }
 169         }
 170
 171         rb_link_node(&block_group->cache_node, parent, p);
 172         rb_insert_color(&block_group->cache_node,
 173                         &info->block_group_cache_tree);
 174
 175         if (info->first_logical_byte > block_group->key.objectid)
 176                 info->first_logical_byte = block_group->key.objectid;
 177
 178         spin_unlock(&info->block_group_cache_lock);
 179
 180         return 0;
 181 }
 182
 183 /*
 184  * This will return the block group at or after bytenr if contains is 0, else
 185  * it will return the block group that contains the bytenr
 186  */
 187 static struct btrfs_block_group_cache *
 188 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 189                               int contains)
 190 {
 191         struct btrfs_block_group_cache *cache, *ret = NULL;
 192         struct rb_node *n;
 193         u64 end, start;
 194
 195         spin_lock(&info->block_group_cache_lock);
 196         n = info->block_group_cache_tree.rb_node;
 197
 198         while (n) {
 199                 cache = rb_entry(n, struct btrfs_block_group_cache,
 200                                  cache_node);
 201                 end = cache->key.objectid + cache->key.offset - 1;
 202                 start = cache->key.objectid;
 203
 204                 if (bytenr < start) {
 205                         if (!contains && (!ret || start < ret->key.objectid))
 206                                 ret = cache;
 207                         n = n->rb_left;
 208                 } else if (bytenr > start) {
 209                         if (contains && bytenr <= end) {
 210                                 ret = cache;
 211                                 break;
 212                         }
 213                         n = n->rb_right;
 214                 } else {
 215                         ret = cache;
 216                         break;
 217                 }
 218         }
 219         if (ret) {
 220                 btrfs_get_block_group(ret);
 221                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 222                         info->first_logical_byte = ret->key.objectid;
 223         }
 224         spin_unlock(&info->block_group_cache_lock);
 225
 226         return ret;
 227 }
 228
 229 static int add_excluded_extent(struct btrfs_root *root,
 230                                u64 start, u64 num_bytes)
 231 {
 232         u64 end = start + num_bytes - 1;
 233         set_extent_bits(&root->fs_info->freed_extents[0],
 234                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 235         set_extent_bits(&root->fs_info->freed_extents[1],
 236                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 237         return 0;
 238 }
 239
 240 static void free_excluded_extents(struct btrfs_root *root,
 241                                   struct btrfs_block_group_cache *cache)
 242 {
 243         u64 start, end;
 244
 245         start = cache->key.objectid;
 246         end = start + cache->key.offset - 1;
 247
 248         clear_extent_bits(&root->fs_info->freed_extents[0],
 249                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 250         clear_extent_bits(&root->fs_info->freed_extents[1],
 251                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 252 }
 253
 254 static int exclude_super_stripes(struct btrfs_root *root,
 255                                  struct btrfs_block_group_cache *cache)
 256 {
 257         u64 bytenr;
 258         u64 *logical;
 259         int stripe_len;
 260         int i, nr, ret;
 261
 262         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 263                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 264                 cache->bytes_super += stripe_len;
 265                 ret = add_excluded_extent(root, cache->key.objectid,
 266                                           stripe_len);
 267                 if (ret)
 268                         return ret;
 269         }
 270
 271         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 272                 bytenr = btrfs_sb_offset(i);
 273                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 274                                        cache->key.objectid, bytenr,
 275                                        0, &logical, &nr, &stripe_len);
 276                 if (ret)
 277                         return ret;
 278
 279                 while (nr--) {
 280                         u64 start, len;
 281
 282                         if (logical[nr] > cache->key.objectid +
 283                             cache->key.offset)
 284                                 continue;
 285
 286                         if (logical[nr] + stripe_len <= cache->key.objectid)
 287                                 continue;
 288
 289                         start = logical[nr];
 290                         if (start < cache->key.objectid) {
 291                                 start = cache->key.objectid;
 292                                 len = (logical[nr] + stripe_len) - start;
 293                         } else {
 294                                 len = min_t(u64, stripe_len,
 295                                             cache->key.objectid +
 296                                             cache->key.offset - start);
 297                         }
 298
 299                         cache->bytes_super += len;
 300                         ret = add_excluded_extent(root, start, len);
 301                         if (ret) {
 302                                 kfree(logical);
 303                                 return ret;
 304                         }
 305                 }
 306
 307                 kfree(logical);
 308         }
 309         return 0;
 310 }
 311
 312 static struct btrfs_caching_control *
 313 get_caching_control(struct btrfs_block_group_cache *cache)
 314 {
 315         struct btrfs_caching_control *ctl;
 316
 317         spin_lock(&cache->lock);
 318         if (!cache->caching_ctl) {
 319                 spin_unlock(&cache->lock);
 320                 return NULL;
 321         }
 322
 323         ctl = cache->caching_ctl;
 324         atomic_inc(&ctl->count);
 325         spin_unlock(&cache->lock);
 326         return ctl;
 327 }
 328
 329 static void put_caching_control(struct btrfs_caching_control *ctl)
 330 {
 331         if (atomic_dec_and_test(&ctl->count))
 332                 kfree(ctl);
 333 }
 334
 335 /*
 336  * this is only called by cache_block_group, since we could have freed extents
 337  * we need to check the pinned_extents for any extents that can't be used yet
 338  * since their free space will be released as soon as the transaction commits.
 339  */
 340 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 341                               struct btrfs_fs_info *info, u64 start, u64 end)
 342 {
 343         u64 extent_start, extent_end, size, total_added = 0;
 344         int ret;
 345
 346         while (start < end) {
 347                 ret = find_first_extent_bit(info->pinned_extents, start,
 348                                             &extent_start, &extent_end,
 349                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 350                                             NULL);
 351                 if (ret)
 352                         break;
 353
 354                 if (extent_start <= start) {
 355                         start = extent_end + 1;
 356                 } else if (extent_start > start && extent_start < end) {
 357                         size = extent_start - start;
 358                         total_added += size;
 359                         ret = btrfs_add_free_space(block_group, start,
 360                                                    size);
 361                         BUG_ON(ret); /* -ENOMEM or logic error */
 362                         start = extent_end + 1;
 363                 } else {
 364                         break;
 365                 }
 366         }
 367
 368         if (start < end) {
 369                 size = end - start;
 370                 total_added += size;
 371                 ret = btrfs_add_free_space(block_group, start, size);
 372                 BUG_ON(ret); /* -ENOMEM or logic error */
 373         }
 374
 375         return total_added;
 376 }
 377
 378 static noinline void caching_thread(struct btrfs_work *work)
 379 {
 380         struct btrfs_block_group_cache *block_group;
 381         struct btrfs_fs_info *fs_info;
 382         struct btrfs_caching_control *caching_ctl;
 383         struct btrfs_root *extent_root;
 384         struct btrfs_path *path;
 385         struct extent_buffer *leaf;
 386         struct btrfs_key key;
 387         u64 total_found = 0;
 388         u64 last = 0;
 389         u32 nritems;
 390         int ret = -ENOMEM;
 391
 392         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 393         block_group = caching_ctl->block_group;
 394         fs_info = block_group->fs_info;
 395         extent_root = fs_info->extent_root;
 396
 397         path = btrfs_alloc_path();
 398         if (!path)
 399                 goto out;
 400
 401         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 402
 403         /*
 404          * We don't want to deadlock with somebody trying to allocate a new
 405          * extent for the extent root while also trying to search the extent
 406          * root to add free space.  So we skip locking and search the commit
 407          * root, since its read-only
 408          */
 409         path->skip_locking = 1;
 410         path->search_commit_root = 1;
 411         path->reada = 1;
 412
 413         key.objectid = last;
 414         key.offset = 0;
 415         key.type = BTRFS_EXTENT_ITEM_KEY;
 416 again:
 417         mutex_lock(&caching_ctl->mutex);
 418         /* need to make sure the commit_root doesn't disappear */
 419         down_read(&fs_info->commit_root_sem);
 420
 421 next:
 422         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 423         if (ret < 0)
 424                 goto err;
 425
 426         leaf = path->nodes[0];
 427         nritems = btrfs_header_nritems(leaf);
 428
 429         while (1) {
 430                 if (btrfs_fs_closing(fs_info) > 1) {
 431                         last = (u64)-1;
 432                         break;
 433                 }
 434
 435                 if (path->slots[0] < nritems) {
 436                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 437                 } else {
 438                         ret = find_next_key(path, 0, &key);
 439                         if (ret)
 440                                 break;
 441
 442                         if (need_resched() ||
 443                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 444                                 caching_ctl->progress = last;
 445                                 btrfs_release_path(path);
 446                                 up_read(&fs_info->commit_root_sem);
 447                                 mutex_unlock(&caching_ctl->mutex);
 448                                 cond_resched();
 449                                 goto again;
 450                         }
 451
 452                         ret = btrfs_next_leaf(extent_root, path);
 453                         if (ret < 0)
 454                                 goto err;
 455                         if (ret)
 456                                 break;
 457                         leaf = path->nodes[0];
 458                         nritems = btrfs_header_nritems(leaf);
 459                         continue;
 460                 }
 461
 462                 if (key.objectid < last) {
 463                         key.objectid = last;
 464                         key.offset = 0;
 465                         key.type = BTRFS_EXTENT_ITEM_KEY;
 466
 467                         caching_ctl->progress = last;
 468                         btrfs_release_path(path);
 469                         goto next;
 470                 }
 471
 472                 if (key.objectid < block_group->key.objectid) {
 473                         path->slots[0]++;
 474                         continue;
 475                 }
 476
 477                 if (key.objectid >= block_group->key.objectid +
 478                     block_group->key.offset)
 479                         break;
 480
 481                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 482                     key.type == BTRFS_METADATA_ITEM_KEY) {
 483                         total_found += add_new_free_space(block_group,
 484                                                           fs_info, last,
 485                                                           key.objectid);
 486                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 487                                 last = key.objectid +
 488                                         fs_info->tree_root->nodesize;
 489                         else
 490                                 last = key.objectid + key.offset;
 491
 492                         if (total_found > (1024 * 1024 * 2)) {
 493                                 total_found = 0;
 494                                 wake_up(&caching_ctl->wait);
 495                         }
 496                 }
 497                 path->slots[0]++;
 498         }
 499         ret = 0;
 500
 501         total_found += add_new_free_space(block_group, fs_info, last,
 502                                           block_group->key.objectid +
 503                                           block_group->key.offset);
 504         caching_ctl->progress = (u64)-1;
 505
 506         spin_lock(&block_group->lock);
 507         block_group->caching_ctl = NULL;
 508         block_group->cached = BTRFS_CACHE_FINISHED;
 509         spin_unlock(&block_group->lock);
 510
 511 err:
 512         btrfs_free_path(path);
 513         up_read(&fs_info->commit_root_sem);
 514
 515         free_excluded_extents(extent_root, block_group);
 516
 517         mutex_unlock(&caching_ctl->mutex);
 518 out:
 519         if (ret) {
 520                 spin_lock(&block_group->lock);
 521                 block_group->caching_ctl = NULL;
 522                 block_group->cached = BTRFS_CACHE_ERROR;
 523                 spin_unlock(&block_group->lock);
 524         }
 525         wake_up(&caching_ctl->wait);
 526
 527         put_caching_control(caching_ctl);
 528         btrfs_put_block_group(block_group);
 529 }
 530
 531 static int cache_block_group(struct btrfs_block_group_cache *cache,
 532                              int load_cache_only)
 533 {
 534         DEFINE_WAIT(wait);
 535         struct btrfs_fs_info *fs_info = cache->fs_info;
 536         struct btrfs_caching_control *caching_ctl;
 537         int ret = 0;
 538
 539         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 540         if (!caching_ctl)
 541                 return -ENOMEM;
 542
 543         INIT_LIST_HEAD(&caching_ctl->list);
 544         mutex_init(&caching_ctl->mutex);
 545         init_waitqueue_head(&caching_ctl->wait);
 546         caching_ctl->block_group = cache;
 547         caching_ctl->progress = cache->key.objectid;
 548         atomic_set(&caching_ctl->count, 1);
 549         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 550                         caching_thread, NULL, NULL);
 551
 552         spin_lock(&cache->lock);
 553         /*
 554          * This should be a rare occasion, but this could happen I think in the
 555          * case where one thread starts to load the space cache info, and then
 556          * some other thread starts a transaction commit which tries to do an
 557          * allocation while the other thread is still loading the space cache
 558          * info.  The previous loop should have kept us from choosing this block
 559          * group, but if we've moved to the state where we will wait on caching
 560          * block groups we need to first check if we're doing a fast load here,
 561          * so we can wait for it to finish, otherwise we could end up allocating
 562          * from a block group who's cache gets evicted for one reason or
 563          * another.
 564          */
 565         while (cache->cached == BTRFS_CACHE_FAST) {
 566                 struct btrfs_caching_control *ctl;
 567
 568                 ctl = cache->caching_ctl;
 569                 atomic_inc(&ctl->count);
 570                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 571                 spin_unlock(&cache->lock);
 572
 573                 schedule();
 574
 575                 finish_wait(&ctl->wait, &wait);
 576                 put_caching_control(ctl);
 577                 spin_lock(&cache->lock);
 578         }
 579
 580         if (cache->cached != BTRFS_CACHE_NO) {
 581                 spin_unlock(&cache->lock);
 582                 kfree(caching_ctl);
 583                 return 0;
 584         }
 585         WARN_ON(cache->caching_ctl);
 586         cache->caching_ctl = caching_ctl;
 587         cache->cached = BTRFS_CACHE_FAST;
 588         spin_unlock(&cache->lock);
 589
 590         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 591                 mutex_lock(&caching_ctl->mutex);
 592                 ret = load_free_space_cache(fs_info, cache);
 593
 594                 spin_lock(&cache->lock);
 595                 if (ret == 1) {
 596                         cache->caching_ctl = NULL;
 597                         cache->cached = BTRFS_CACHE_FINISHED;
 598                         cache->last_byte_to_unpin = (u64)-1;
 599                         caching_ctl->progress = (u64)-1;
 600                 } else {
 601                         if (load_cache_only) {
 602                                 cache->caching_ctl = NULL;
 603                                 cache->cached = BTRFS_CACHE_NO;
 604                         } else {
 605                                 cache->cached = BTRFS_CACHE_STARTED;
 606                                 cache->has_caching_ctl = 1;
 607                         }
 608                 }
 609                 spin_unlock(&cache->lock);
 610                 mutex_unlock(&caching_ctl->mutex);
 611
 612                 wake_up(&caching_ctl->wait);
 613                 if (ret == 1) {
 614                         put_caching_control(caching_ctl);
 615                         free_excluded_extents(fs_info->extent_root, cache);
 616                         return 0;
 617                 }
 618         } else {
 619                 /*
 620                  * We are not going to do the fast caching, set cached to the
 621                  * appropriate value and wakeup any waiters.
 622                  */
 623                 spin_lock(&cache->lock);
 624                 if (load_cache_only) {
 625                         cache->caching_ctl = NULL;
 626                         cache->cached = BTRFS_CACHE_NO;
 627                 } else {
 628                         cache->cached = BTRFS_CACHE_STARTED;
 629                         cache->has_caching_ctl = 1;
 630                 }
 631                 spin_unlock(&cache->lock);
 632                 wake_up(&caching_ctl->wait);
 633         }
 634
 635         if (load_cache_only) {
 636                 put_caching_control(caching_ctl);
 637                 return 0;
 638         }
 639
 640         down_write(&fs_info->commit_root_sem);
 641         atomic_inc(&caching_ctl->count);
 642         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 643         up_write(&fs_info->commit_root_sem);
 644
 645         btrfs_get_block_group(cache);
 646
 647         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 648
 649         return ret;
 650 }
 651
 652 /*
 653  * return the block group that starts at or after bytenr
 654  */
 655 static struct btrfs_block_group_cache *
 656 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 657 {
 658         struct btrfs_block_group_cache *cache;
 659
 660         cache = block_group_cache_tree_search(info, bytenr, 0);
 661
 662         return cache;
 663 }
 664
 665 /*
 666  * return the block group that contains the given bytenr
 667  */
 668 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 669                                                  struct btrfs_fs_info *info,
 670                                                  u64 bytenr)
 671 {
 672         struct btrfs_block_group_cache *cache;
 673
 674         cache = block_group_cache_tree_search(info, bytenr, 1);
 675
 676         return cache;
 677 }
 678
 679 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 680                                                   u64 flags)
 681 {
 682         struct list_head *head = &info->space_info;
 683         struct btrfs_space_info *found;
 684
 685         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 686
 687         rcu_read_lock();
 688         list_for_each_entry_rcu(found, head, list) {
 689                 if (found->flags & flags) {
 690                         rcu_read_unlock();
 691                         return found;
 692                 }
 693         }
 694         rcu_read_unlock();
 695         return NULL;
 696 }
 697
 698 /*
 699  * after adding space to the filesystem, we need to clear the full flags
 700  * on all the space infos.
 701  */
 702 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 703 {
 704         struct list_head *head = &info->space_info;
 705         struct btrfs_space_info *found;
 706
 707         rcu_read_lock();
 708         list_for_each_entry_rcu(found, head, list)
 709                 found->full = 0;
 710         rcu_read_unlock();
 711 }
 712
 713 /* simple helper to search for an existing data extent at a given offset */
 714 int btrfs_lookup_data_extent(struct btrfs_root *root, u64 start, u64 len)
 715 {
 716         int ret;
 717         struct btrfs_key key;
 718         struct btrfs_path *path;
 719
 720         path = btrfs_alloc_path();
 721         if (!path)
 722                 return -ENOMEM;
 723
 724         key.objectid = start;
 725         key.offset = len;
 726         key.type = BTRFS_EXTENT_ITEM_KEY;
 727         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 728                                 0, 0);
 729         btrfs_free_path(path);
 730         return ret;
 731 }
 732
 733 /*
 734  * helper function to lookup reference count and flags of a tree block.
 735  *
 736  * the head node for delayed ref is used to store the sum of all the
 737  * reference count modifications queued up in the rbtree. the head
 738  * node may also store the extent flags to set. This way you can check
 739  * to see what the reference count and extent flags would be if all of
 740  * the delayed refs are not processed.
 741  */
 742 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 743                              struct btrfs_root *root, u64 bytenr,
 744                              u64 offset, int metadata, u64 *refs, u64 *flags)
 745 {
 746         struct btrfs_delayed_ref_head *head;
 747         struct btrfs_delayed_ref_root *delayed_refs;
 748         struct btrfs_path *path;
 749         struct btrfs_extent_item *ei;
 750         struct extent_buffer *leaf;
 751         struct btrfs_key key;
 752         u32 item_size;
 753         u64 num_refs;
 754         u64 extent_flags;
 755         int ret;
 756
 757         /*
 758          * If we don't have skinny metadata, don't bother doing anything
 759          * different
 760          */
 761         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA)) {
 762                 offset = root->nodesize;
 763                 metadata = 0;
 764         }
 765
 766         path = btrfs_alloc_path();
 767         if (!path)
 768                 return -ENOMEM;
 769
 770         if (!trans) {
 771                 path->skip_locking = 1;
 772                 path->search_commit_root = 1;
 773         }
 774
 775 search_again:
 776         key.objectid = bytenr;
 777         key.offset = offset;
 778         if (metadata)
 779                 key.type = BTRFS_METADATA_ITEM_KEY;
 780         else
 781                 key.type = BTRFS_EXTENT_ITEM_KEY;
 782
 783         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 784                                 &key, path, 0, 0);
 785         if (ret < 0)
 786                 goto out_free;
 787
 788         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 789                 if (path->slots[0]) {
 790                         path->slots[0]--;
 791                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 792                                               path->slots[0]);
 793                         if (key.objectid == bytenr &&
 794                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 795                             key.offset == root->nodesize)
 796                                 ret = 0;
 797                 }
 798         }
 799
 800         if (ret == 0) {
 801                 leaf = path->nodes[0];
 802                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 803                 if (item_size >= sizeof(*ei)) {
 804                         ei = btrfs_item_ptr(leaf, path->slots[0],
 805                                             struct btrfs_extent_item);
 806                         num_refs = btrfs_extent_refs(leaf, ei);
 807                         extent_flags = btrfs_extent_flags(leaf, ei);
 808                 } else {
 809 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 810                         struct btrfs_extent_item_v0 *ei0;
 811                         BUG_ON(item_size != sizeof(*ei0));
 812                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 813                                              struct btrfs_extent_item_v0);
 814                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 815                         /* FIXME: this isn't correct for data */
 816                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 817 #else
 818                         BUG();
 819 #endif
 820                 }
 821                 BUG_ON(num_refs == 0);
 822         } else {
 823                 num_refs = 0;
 824                 extent_flags = 0;
 825                 ret = 0;
 826         }
 827
 828         if (!trans)
 829                 goto out;
 830
 831         delayed_refs = &trans->transaction->delayed_refs;
 832         spin_lock(&delayed_refs->lock);
 833         head = btrfs_find_delayed_ref_head(trans, bytenr);
 834         if (head) {
 835                 if (!mutex_trylock(&head->mutex)) {
 836                         atomic_inc(&head->node.refs);
 837                         spin_unlock(&delayed_refs->lock);
 838
 839                         btrfs_release_path(path);
 840
 841                         /*
 842                          * Mutex was contended, block until it's released and try
 843                          * again
 844                          */
 845                         mutex_lock(&head->mutex);
 846                         mutex_unlock(&head->mutex);
 847                         btrfs_put_delayed_ref(&head->node);
 848                         goto search_again;
 849                 }
 850                 spin_lock(&head->lock);
 851                 if (head->extent_op && head->extent_op->update_flags)
 852                         extent_flags |= head->extent_op->flags_to_set;
 853                 else
 854                         BUG_ON(num_refs == 0);
 855
 856                 num_refs += head->node.ref_mod;
 857                 spin_unlock(&head->lock);
 858                 mutex_unlock(&head->mutex);
 859         }
 860         spin_unlock(&delayed_refs->lock);
 861 out:
 862         WARN_ON(num_refs == 0);
 863         if (refs)
 864                 *refs = num_refs;
 865         if (flags)
 866                 *flags = extent_flags;
 867 out_free:
 868         btrfs_free_path(path);
 869         return ret;
 870 }
 871
 872 /*
 873  * Back reference rules.  Back refs have three main goals:
 874  *
 875  * 1) differentiate between all holders of references to an extent so that
 876  *    when a reference is dropped we can make sure it was a valid reference
 877  *    before freeing the extent.
 878  *
 879  * 2) Provide enough information to quickly find the holders of an extent
 880  *    if we notice a given block is corrupted or bad.
 881  *
 882  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 883  *    maintenance.  This is actually the same as #2, but with a slightly
 884  *    different use case.
 885  *
 886  * There are two kinds of back refs. The implicit back refs is optimized
 887  * for pointers in non-shared tree blocks. For a given pointer in a block,
 888  * back refs of this kind provide information about the block's owner tree
 889  * and the pointer's key. These information allow us to find the block by
 890  * b-tree searching. The full back refs is for pointers in tree blocks not
 891  * referenced by their owner trees. The location of tree block is recorded
 892  * in the back refs. Actually the full back refs is generic, and can be
 893  * used in all cases the implicit back refs is used. The major shortcoming
 894  * of the full back refs is its overhead. Every time a tree block gets
 895  * COWed, we have to update back refs entry for all pointers in it.
 896  *
 897  * For a newly allocated tree block, we use implicit back refs for
 898  * pointers in it. This means most tree related operations only involve
 899  * implicit back refs. For a tree block created in old transaction, the
 900  * only way to drop a reference to it is COW it. So we can detect the
 901  * event that tree block loses its owner tree's reference and do the
 902  * back refs conversion.
 903  *
 904  * When a tree block is COW'd through a tree, there are four cases:
 905  *
 906  * The reference count of the block is one and the tree is the block's
 907  * owner tree. Nothing to do in this case.
 908  *
 909  * The reference count of the block is one and the tree is not the
 910  * block's owner tree. In this case, full back refs is used for pointers
 911  * in the block. Remove these full back refs, add implicit back refs for
 912  * every pointers in the new block.
 913  *
 914  * The reference count of the block is greater than one and the tree is
 915  * the block's owner tree. In this case, implicit back refs is used for
 916  * pointers in the block. Add full back refs for every pointers in the
 917  * block, increase lower level extents' reference counts. The original
 918  * implicit back refs are entailed to the new block.
 919  *
 920  * The reference count of the block is greater than one and the tree is
 921  * not the block's owner tree. Add implicit back refs for every pointer in
 922  * the new block, increase lower level extents' reference count.
 923  *
 924  * Back Reference Key composing:
 925  *
 926  * The key objectid corresponds to the first byte in the extent,
 927  * The key type is used to differentiate between types of back refs.
 928  * There are different meanings of the key offset for different types
 929  * of back refs.
 930  *
 931  * File extents can be referenced by:
 932  *
 933  * - multiple snapshots, subvolumes, or different generations in one subvol
 934  * - different files inside a single subvolume
 935  * - different offsets inside a file (bookend extents in file.c)
 936  *
 937  * The extent ref structure for the implicit back refs has fields for:
 938  *
 939  * - Objectid of the subvolume root
 940  * - objectid of the file holding the reference
 941  * - original offset in the file
 942  * - how many bookend extents
 943  *
 944  * The key offset for the implicit back refs is hash of the first
 945  * three fields.
 946  *
 947  * The extent ref structure for the full back refs has field for:
 948  *
 949  * - number of pointers in the tree leaf
 950  *
 951  * The key offset for the implicit back refs is the first byte of
 952  * the tree leaf
 953  *
 954  * When a file extent is allocated, The implicit back refs is used.
 955  * the fields are filled in:
 956  *
 957  *     (root_key.objectid, inode objectid, offset in file, 1)
 958  *
 959  * When a file extent is removed file truncation, we find the
 960  * corresponding implicit back refs and check the following fields:
 961  *
 962  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 963  *
 964  * Btree extents can be referenced by:
 965  *
 966  * - Different subvolumes
 967  *
 968  * Both the implicit back refs and the full back refs for tree blocks
 969  * only consist of key. The key offset for the implicit back refs is
 970  * objectid of block's owner tree. The key offset for the full back refs
 971  * is the first byte of parent block.
 972  *
 973  * When implicit back refs is used, information about the lowest key and
 974  * level of the tree block are required. These information are stored in
 975  * tree block info structure.
 976  */
 977
 978 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 979 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 980                                   struct btrfs_root *root,
 981                                   struct btrfs_path *path,
 982                                   u64 owner, u32 extra_size)
 983 {
 984         struct btrfs_extent_item *item;
 985         struct btrfs_extent_item_v0 *ei0;
 986         struct btrfs_extent_ref_v0 *ref0;
 987         struct btrfs_tree_block_info *bi;
 988         struct extent_buffer *leaf;
 989         struct btrfs_key key;
 990         struct btrfs_key found_key;
 991         u32 new_size = sizeof(*item);
 992         u64 refs;
 993         int ret;
 994
 995         leaf = path->nodes[0];
 996         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
 997
 998         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 999         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1000                              struct btrfs_extent_item_v0);
1001         refs = btrfs_extent_refs_v0(leaf, ei0);
1002
1003         if (owner == (u64)-1) {
1004                 while (1) {
1005                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1006                                 ret = btrfs_next_leaf(root, path);
1007                                 if (ret < 0)
1008                                         return ret;
1009                                 BUG_ON(ret > 0); /* Corruption */
1010                                 leaf = path->nodes[0];
1011                         }
1012                         btrfs_item_key_to_cpu(leaf, &found_key,
1013                                               path->slots[0]);
1014                         BUG_ON(key.objectid != found_key.objectid);
1015                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1016                                 path->slots[0]++;
1017                                 continue;
1018                         }
1019                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1020                                               struct btrfs_extent_ref_v0);
1021                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1022                         break;
1023                 }
1024         }
1025         btrfs_release_path(path);
1026
1027         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1028                 new_size += sizeof(*bi);
1029
1030         new_size -= sizeof(*ei0);
1031         ret = btrfs_search_slot(trans, root, &key, path,
1032                                 new_size + extra_size, 1);
1033         if (ret < 0)
1034                 return ret;
1035         BUG_ON(ret); /* Corruption */
1036
1037         btrfs_extend_item(root, path, new_size);
1038
1039         leaf = path->nodes[0];
1040         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1041         btrfs_set_extent_refs(leaf, item, refs);
1042         /* FIXME: get real generation */
1043         btrfs_set_extent_generation(leaf, item, 0);
1044         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1045                 btrfs_set_extent_flags(leaf, item,
1046                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1047                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1048                 bi = (struct btrfs_tree_block_info *)(item + 1);
1049                 /* FIXME: get first key of the block */
1050                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1051                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1052         } else {
1053                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1054         }
1055         btrfs_mark_buffer_dirty(leaf);
1056         return 0;
1057 }
1058 #endif
1059
1060 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1061 {
1062         u32 high_crc = ~(u32)0;
1063         u32 low_crc = ~(u32)0;
1064         __le64 lenum;
1065
1066         lenum = cpu_to_le64(root_objectid);
1067         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1068         lenum = cpu_to_le64(owner);
1069         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1070         lenum = cpu_to_le64(offset);
1071         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1072
1073         return ((u64)high_crc << 31) ^ (u64)low_crc;
1074 }
1075
1076 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1077                                      struct btrfs_extent_data_ref *ref)
1078 {
1079         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1080                                     btrfs_extent_data_ref_objectid(leaf, ref),
1081                                     btrfs_extent_data_ref_offset(leaf, ref));
1082 }
1083
1084 static int match_extent_data_ref(struct extent_buffer *leaf,
1085                                  struct btrfs_extent_data_ref *ref,
1086                                  u64 root_objectid, u64 owner, u64 offset)
1087 {
1088         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1089             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1090             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1091                 return 0;
1092         return 1;
1093 }
1094
1095 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1096                                            struct btrfs_root *root,
1097                                            struct btrfs_path *path,
1098                                            u64 bytenr, u64 parent,
1099                                            u64 root_objectid,
1100                                            u64 owner, u64 offset)
1101 {
1102         struct btrfs_key key;
1103         struct btrfs_extent_data_ref *ref;
1104         struct extent_buffer *leaf;
1105         u32 nritems;
1106         int ret;
1107         int recow;
1108         int err = -ENOENT;
1109
1110         key.objectid = bytenr;
1111         if (parent) {
1112                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1113                 key.offset = parent;
1114         } else {
1115                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1116                 key.offset = hash_extent_data_ref(root_objectid,
1117                                                   owner, offset);
1118         }
1119 again:
1120         recow = 0;
1121         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1122         if (ret < 0) {
1123                 err = ret;
1124                 goto fail;
1125         }
1126
1127         if (parent) {
1128                 if (!ret)
1129                         return 0;
1130 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1131                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1132                 btrfs_release_path(path);
1133                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1134                 if (ret < 0) {
1135                         err = ret;
1136                         goto fail;
1137                 }
1138                 if (!ret)
1139                         return 0;
1140 #endif
1141                 goto fail;
1142         }
1143
1144         leaf = path->nodes[0];
1145         nritems = btrfs_header_nritems(leaf);
1146         while (1) {
1147                 if (path->slots[0] >= nritems) {
1148                         ret = btrfs_next_leaf(root, path);
1149                         if (ret < 0)
1150                                 err = ret;
1151                         if (ret)
1152                                 goto fail;
1153
1154                         leaf = path->nodes[0];
1155                         nritems = btrfs_header_nritems(leaf);
1156                         recow = 1;
1157                 }
1158
1159                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1160                 if (key.objectid != bytenr ||
1161                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1162                         goto fail;
1163
1164                 ref = btrfs_item_ptr(leaf, path->slots[0],
1165                                      struct btrfs_extent_data_ref);
1166
1167                 if (match_extent_data_ref(leaf, ref, root_objectid,
1168                                           owner, offset)) {
1169                         if (recow) {
1170                                 btrfs_release_path(path);
1171                                 goto again;
1172                         }
1173                         err = 0;
1174                         break;
1175                 }
1176                 path->slots[0]++;
1177         }
1178 fail:
1179         return err;
1180 }
1181
1182 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1183                                            struct btrfs_root *root,
1184                                            struct btrfs_path *path,
1185                                            u64 bytenr, u64 parent,
1186                                            u64 root_objectid, u64 owner,
1187                                            u64 offset, int refs_to_add)
1188 {
1189         struct btrfs_key key;
1190         struct extent_buffer *leaf;
1191         u32 size;
1192         u32 num_refs;
1193         int ret;
1194
1195         key.objectid = bytenr;
1196         if (parent) {
1197                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1198                 key.offset = parent;
1199                 size = sizeof(struct btrfs_shared_data_ref);
1200         } else {
1201                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1202                 key.offset = hash_extent_data_ref(root_objectid,
1203                                                   owner, offset);
1204                 size = sizeof(struct btrfs_extent_data_ref);
1205         }
1206
1207         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1208         if (ret && ret != -EEXIST)
1209                 goto fail;
1210
1211         leaf = path->nodes[0];
1212         if (parent) {
1213                 struct btrfs_shared_data_ref *ref;
1214                 ref = btrfs_item_ptr(leaf, path->slots[0],
1215                                      struct btrfs_shared_data_ref);
1216                 if (ret == 0) {
1217                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1218                 } else {
1219                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1220                         num_refs += refs_to_add;
1221                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1222                 }
1223         } else {
1224                 struct btrfs_extent_data_ref *ref;
1225                 while (ret == -EEXIST) {
1226                         ref = btrfs_item_ptr(leaf, path->slots[0],
1227                                              struct btrfs_extent_data_ref);
1228                         if (match_extent_data_ref(leaf, ref, root_objectid,
1229                                                   owner, offset))
1230                                 break;
1231                         btrfs_release_path(path);
1232                         key.offset++;
1233                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1234                                                       size);
1235                         if (ret && ret != -EEXIST)
1236                                 goto fail;
1237
1238                         leaf = path->nodes[0];
1239                 }
1240                 ref = btrfs_item_ptr(leaf, path->slots[0],
1241                                      struct btrfs_extent_data_ref);
1242                 if (ret == 0) {
1243                         btrfs_set_extent_data_ref_root(leaf, ref,
1244                                                        root_objectid);
1245                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1246                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1247                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1248                 } else {
1249                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1250                         num_refs += refs_to_add;
1251                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1252                 }
1253         }
1254         btrfs_mark_buffer_dirty(leaf);
1255         ret = 0;
1256 fail:
1257         btrfs_release_path(path);
1258         return ret;
1259 }
1260
1261 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1262                                            struct btrfs_root *root,
1263                                            struct btrfs_path *path,
1264                                            int refs_to_drop, int *last_ref)
1265 {
1266         struct btrfs_key key;
1267         struct btrfs_extent_data_ref *ref1 = NULL;
1268         struct btrfs_shared_data_ref *ref2 = NULL;
1269         struct extent_buffer *leaf;
1270         u32 num_refs = 0;
1271         int ret = 0;
1272
1273         leaf = path->nodes[0];
1274         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1275
1276         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1277                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1278                                       struct btrfs_extent_data_ref);
1279                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1280         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1281                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1282                                       struct btrfs_shared_data_ref);
1283                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1284 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1285         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1286                 struct btrfs_extent_ref_v0 *ref0;
1287                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1288                                       struct btrfs_extent_ref_v0);
1289                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1290 #endif
1291         } else {
1292                 BUG();
1293         }
1294
1295         BUG_ON(num_refs < refs_to_drop);
1296         num_refs -= refs_to_drop;
1297
1298         if (num_refs == 0) {
1299                 ret = btrfs_del_item(trans, root, path);
1300                 *last_ref = 1;
1301         } else {
1302                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1303                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1304                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1305                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1306 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1307                 else {
1308                         struct btrfs_extent_ref_v0 *ref0;
1309                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1310                                         struct btrfs_extent_ref_v0);
1311                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1312                 }
1313 #endif
1314                 btrfs_mark_buffer_dirty(leaf);
1315         }
1316         return ret;
1317 }
1318
1319 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1320                                           struct btrfs_extent_inline_ref *iref)
1321 {
1322         struct btrfs_key key;
1323         struct extent_buffer *leaf;
1324         struct btrfs_extent_data_ref *ref1;
1325         struct btrfs_shared_data_ref *ref2;
1326         u32 num_refs = 0;
1327
1328         leaf = path->nodes[0];
1329         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1330         if (iref) {
1331                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1332                     BTRFS_EXTENT_DATA_REF_KEY) {
1333                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1334                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1335                 } else {
1336                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1337                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1338                 }
1339         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1340                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1341                                       struct btrfs_extent_data_ref);
1342                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1343         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1344                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1345                                       struct btrfs_shared_data_ref);
1346                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1347 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1348         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1349                 struct btrfs_extent_ref_v0 *ref0;
1350                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1351                                       struct btrfs_extent_ref_v0);
1352                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1353 #endif
1354         } else {
1355                 WARN_ON(1);
1356         }
1357         return num_refs;
1358 }
1359
1360 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1361                                           struct btrfs_root *root,
1362                                           struct btrfs_path *path,
1363                                           u64 bytenr, u64 parent,
1364                                           u64 root_objectid)
1365 {
1366         struct btrfs_key key;
1367         int ret;
1368
1369         key.objectid = bytenr;
1370         if (parent) {
1371                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1372                 key.offset = parent;
1373         } else {
1374                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1375                 key.offset = root_objectid;
1376         }
1377
1378         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1379         if (ret > 0)
1380                 ret = -ENOENT;
1381 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1382         if (ret == -ENOENT && parent) {
1383                 btrfs_release_path(path);
1384                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1385                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1386                 if (ret > 0)
1387                         ret = -ENOENT;
1388         }
1389 #endif
1390         return ret;
1391 }
1392
1393 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1394                                           struct btrfs_root *root,
1395                                           struct btrfs_path *path,
1396                                           u64 bytenr, u64 parent,
1397                                           u64 root_objectid)
1398 {
1399         struct btrfs_key key;
1400         int ret;
1401
1402         key.objectid = bytenr;
1403         if (parent) {
1404                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1405                 key.offset = parent;
1406         } else {
1407                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1408                 key.offset = root_objectid;
1409         }
1410
1411         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1412         btrfs_release_path(path);
1413         return ret;
1414 }
1415
1416 static inline int extent_ref_type(u64 parent, u64 owner)
1417 {
1418         int type;
1419         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1420                 if (parent > 0)
1421                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1422                 else
1423                         type = BTRFS_TREE_BLOCK_REF_KEY;
1424         } else {
1425                 if (parent > 0)
1426                         type = BTRFS_SHARED_DATA_REF_KEY;
1427                 else
1428                         type = BTRFS_EXTENT_DATA_REF_KEY;
1429         }
1430         return type;
1431 }
1432
1433 static int find_next_key(struct btrfs_path *path, int level,
1434                          struct btrfs_key *key)
1435
1436 {
1437         for (; level < BTRFS_MAX_LEVEL; level++) {
1438                 if (!path->nodes[level])
1439                         break;
1440                 if (path->slots[level] + 1 >=
1441                     btrfs_header_nritems(path->nodes[level]))
1442                         continue;
1443                 if (level == 0)
1444                         btrfs_item_key_to_cpu(path->nodes[level], key,
1445                                               path->slots[level] + 1);
1446                 else
1447                         btrfs_node_key_to_cpu(path->nodes[level], key,
1448                                               path->slots[level] + 1);
1449                 return 0;
1450         }
1451         return 1;
1452 }
1453
1454 /*
1455  * look for inline back ref. if back ref is found, *ref_ret is set
1456  * to the address of inline back ref, and 0 is returned.
1457  *
1458  * if back ref isn't found, *ref_ret is set to the address where it
1459  * should be inserted, and -ENOENT is returned.
1460  *
1461  * if insert is true and there are too many inline back refs, the path
1462  * points to the extent item, and -EAGAIN is returned.
1463  *
1464  * NOTE: inline back refs are ordered in the same way that back ref
1465  *       items in the tree are ordered.
1466  */
1467 static noinline_for_stack
1468 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1469                                  struct btrfs_root *root,
1470                                  struct btrfs_path *path,
1471                                  struct btrfs_extent_inline_ref **ref_ret,
1472                                  u64 bytenr, u64 num_bytes,
1473                                  u64 parent, u64 root_objectid,
1474                                  u64 owner, u64 offset, int insert)
1475 {
1476         struct btrfs_key key;
1477         struct extent_buffer *leaf;
1478         struct btrfs_extent_item *ei;
1479         struct btrfs_extent_inline_ref *iref;
1480         u64 flags;
1481         u64 item_size;
1482         unsigned long ptr;
1483         unsigned long end;
1484         int extra_size;
1485         int type;
1486         int want;
1487         int ret;
1488         int err = 0;
1489         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1490                                                  SKINNY_METADATA);
1491
1492         key.objectid = bytenr;
1493         key.type = BTRFS_EXTENT_ITEM_KEY;
1494         key.offset = num_bytes;
1495
1496         want = extent_ref_type(parent, owner);
1497         if (insert) {
1498                 extra_size = btrfs_extent_inline_ref_size(want);
1499                 path->keep_locks = 1;
1500         } else
1501                 extra_size = -1;
1502
1503         /*
1504          * Owner is our parent level, so we can just add one to get the level
1505          * for the block we are interested in.
1506          */
1507         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1508                 key.type = BTRFS_METADATA_ITEM_KEY;
1509                 key.offset = owner;
1510         }
1511
1512 again:
1513         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1514         if (ret < 0) {
1515                 err = ret;
1516                 goto out;
1517         }
1518
1519         /*
1520          * We may be a newly converted file system which still has the old fat
1521          * extent entries for metadata, so try and see if we have one of those.
1522          */
1523         if (ret > 0 && skinny_metadata) {
1524                 skinny_metadata = false;
1525                 if (path->slots[0]) {
1526                         path->slots[0]--;
1527                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1528                                               path->slots[0]);
1529                         if (key.objectid == bytenr &&
1530                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1531                             key.offset == num_bytes)
1532                                 ret = 0;
1533                 }
1534                 if (ret) {
1535                         key.objectid = bytenr;
1536                         key.type = BTRFS_EXTENT_ITEM_KEY;
1537                         key.offset = num_bytes;
1538                         btrfs_release_path(path);
1539                         goto again;
1540                 }
1541         }
1542
1543         if (ret && !insert) {
1544                 err = -ENOENT;
1545                 goto out;
1546         } else if (WARN_ON(ret)) {
1547                 err = -EIO;
1548                 goto out;
1549         }
1550
1551         leaf = path->nodes[0];
1552         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1553 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1554         if (item_size < sizeof(*ei)) {
1555                 if (!insert) {
1556                         err = -ENOENT;
1557                         goto out;
1558                 }
1559                 ret = convert_extent_item_v0(trans, root, path, owner,
1560                                              extra_size);
1561                 if (ret < 0) {
1562                         err = ret;
1563                         goto out;
1564                 }
1565                 leaf = path->nodes[0];
1566                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1567         }
1568 #endif
1569         BUG_ON(item_size < sizeof(*ei));
1570
1571         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1572         flags = btrfs_extent_flags(leaf, ei);
1573
1574         ptr = (unsigned long)(ei + 1);
1575         end = (unsigned long)ei + item_size;
1576
1577         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1578                 ptr += sizeof(struct btrfs_tree_block_info);
1579                 BUG_ON(ptr > end);
1580         }
1581
1582         err = -ENOENT;
1583         while (1) {
1584                 if (ptr >= end) {
1585                         WARN_ON(ptr > end);
1586                         break;
1587                 }
1588                 iref = (struct btrfs_extent_inline_ref *)ptr;
1589                 type = btrfs_extent_inline_ref_type(leaf, iref);
1590                 if (want < type)
1591                         break;
1592                 if (want > type) {
1593                         ptr += btrfs_extent_inline_ref_size(type);
1594                         continue;
1595                 }
1596
1597                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1598                         struct btrfs_extent_data_ref *dref;
1599                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1600                         if (match_extent_data_ref(leaf, dref, root_objectid,
1601                                                   owner, offset)) {
1602                                 err = 0;
1603                                 break;
1604                         }
1605                         if (hash_extent_data_ref_item(leaf, dref) <
1606                             hash_extent_data_ref(root_objectid, owner, offset))
1607                                 break;
1608                 } else {
1609                         u64 ref_offset;
1610                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1611                         if (parent > 0) {
1612                                 if (parent == ref_offset) {
1613                                         err = 0;
1614                                         break;
1615                                 }
1616                                 if (ref_offset < parent)
1617                                         break;
1618                         } else {
1619                                 if (root_objectid == ref_offset) {
1620                                         err = 0;
1621                                         break;
1622                                 }
1623                                 if (ref_offset < root_objectid)
1624                                         break;
1625                         }
1626                 }
1627                 ptr += btrfs_extent_inline_ref_size(type);
1628         }
1629         if (err == -ENOENT && insert) {
1630                 if (item_size + extra_size >=
1631                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1632                         err = -EAGAIN;
1633                         goto out;
1634                 }
1635                 /*
1636                  * To add new inline back ref, we have to make sure
1637                  * there is no corresponding back ref item.
1638                  * For simplicity, we just do not add new inline back
1639                  * ref if there is any kind of item for this block
1640                  */
1641                 if (find_next_key(path, 0, &key) == 0 &&
1642                     key.objectid == bytenr &&
1643                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1644                         err = -EAGAIN;
1645                         goto out;
1646                 }
1647         }
1648         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1649 out:
1650         if (insert) {
1651                 path->keep_locks = 0;
1652                 btrfs_unlock_up_safe(path, 1);
1653         }
1654         return err;
1655 }
1656
1657 /*
1658  * helper to add new inline back ref
1659  */
1660 static noinline_for_stack
1661 void setup_inline_extent_backref(struct btrfs_root *root,
1662                                  struct btrfs_path *path,
1663                                  struct btrfs_extent_inline_ref *iref,
1664                                  u64 parent, u64 root_objectid,
1665                                  u64 owner, u64 offset, int refs_to_add,
1666                                  struct btrfs_delayed_extent_op *extent_op)
1667 {
1668         struct extent_buffer *leaf;
1669         struct btrfs_extent_item *ei;
1670         unsigned long ptr;
1671         unsigned long end;
1672         unsigned long item_offset;
1673         u64 refs;
1674         int size;
1675         int type;
1676
1677         leaf = path->nodes[0];
1678         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1679         item_offset = (unsigned long)iref - (unsigned long)ei;
1680
1681         type = extent_ref_type(parent, owner);
1682         size = btrfs_extent_inline_ref_size(type);
1683
1684         btrfs_extend_item(root, path, size);
1685
1686         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1687         refs = btrfs_extent_refs(leaf, ei);
1688         refs += refs_to_add;
1689         btrfs_set_extent_refs(leaf, ei, refs);
1690         if (extent_op)
1691                 __run_delayed_extent_op(extent_op, leaf, ei);
1692
1693         ptr = (unsigned long)ei + item_offset;
1694         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1695         if (ptr < end - size)
1696                 memmove_extent_buffer(leaf, ptr + size, ptr,
1697                                       end - size - ptr);
1698
1699         iref = (struct btrfs_extent_inline_ref *)ptr;
1700         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1701         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1702                 struct btrfs_extent_data_ref *dref;
1703                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1704                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1705                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1706                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1707                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1708         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1709                 struct btrfs_shared_data_ref *sref;
1710                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1711                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1712                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1713         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1714                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1715         } else {
1716                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1717         }
1718         btrfs_mark_buffer_dirty(leaf);
1719 }
1720
1721 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1722                                  struct btrfs_root *root,
1723                                  struct btrfs_path *path,
1724                                  struct btrfs_extent_inline_ref **ref_ret,
1725                                  u64 bytenr, u64 num_bytes, u64 parent,
1726                                  u64 root_objectid, u64 owner, u64 offset)
1727 {
1728         int ret;
1729
1730         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1731                                            bytenr, num_bytes, parent,
1732                                            root_objectid, owner, offset, 0);
1733         if (ret != -ENOENT)
1734                 return ret;
1735
1736         btrfs_release_path(path);
1737         *ref_ret = NULL;
1738
1739         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1740                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1741                                             root_objectid);
1742         } else {
1743                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1744                                              root_objectid, owner, offset);
1745         }
1746         return ret;
1747 }
1748
1749 /*
1750  * helper to update/remove inline back ref
1751  */
1752 static noinline_for_stack
1753 void update_inline_extent_backref(struct btrfs_root *root,
1754                                   struct btrfs_path *path,
1755                                   struct btrfs_extent_inline_ref *iref,
1756                                   int refs_to_mod,
1757                                   struct btrfs_delayed_extent_op *extent_op,
1758                                   int *last_ref)
1759 {
1760         struct extent_buffer *leaf;
1761         struct btrfs_extent_item *ei;
1762         struct btrfs_extent_data_ref *dref = NULL;
1763         struct btrfs_shared_data_ref *sref = NULL;
1764         unsigned long ptr;
1765         unsigned long end;
1766         u32 item_size;
1767         int size;
1768         int type;
1769         u64 refs;
1770
1771         leaf = path->nodes[0];
1772         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1773         refs = btrfs_extent_refs(leaf, ei);
1774         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1775         refs += refs_to_mod;
1776         btrfs_set_extent_refs(leaf, ei, refs);
1777         if (extent_op)
1778                 __run_delayed_extent_op(extent_op, leaf, ei);
1779
1780         type = btrfs_extent_inline_ref_type(leaf, iref);
1781
1782         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1783                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1784                 refs = btrfs_extent_data_ref_count(leaf, dref);
1785         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1786                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1787                 refs = btrfs_shared_data_ref_count(leaf, sref);
1788         } else {
1789                 refs = 1;
1790                 BUG_ON(refs_to_mod != -1);
1791         }
1792
1793         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1794         refs += refs_to_mod;
1795
1796         if (refs > 0) {
1797                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1798                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1799                 else
1800                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1801         } else {
1802                 *last_ref = 1;
1803                 size =  btrfs_extent_inline_ref_size(type);
1804                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1805                 ptr = (unsigned long)iref;
1806                 end = (unsigned long)ei + item_size;
1807                 if (ptr + size < end)
1808                         memmove_extent_buffer(leaf, ptr, ptr + size,
1809                                               end - ptr - size);
1810                 item_size -= size;
1811                 btrfs_truncate_item(root, path, item_size, 1);
1812         }
1813         btrfs_mark_buffer_dirty(leaf);
1814 }
1815
1816 static noinline_for_stack
1817 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1818                                  struct btrfs_root *root,
1819                                  struct btrfs_path *path,
1820                                  u64 bytenr, u64 num_bytes, u64 parent,
1821                                  u64 root_objectid, u64 owner,
1822                                  u64 offset, int refs_to_add,
1823                                  struct btrfs_delayed_extent_op *extent_op)
1824 {
1825         struct btrfs_extent_inline_ref *iref;
1826         int ret;
1827
1828         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1829                                            bytenr, num_bytes, parent,
1830                                            root_objectid, owner, offset, 1);
1831         if (ret == 0) {
1832                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1833                 update_inline_extent_backref(root, path, iref,
1834                                              refs_to_add, extent_op, NULL);
1835         } else if (ret == -ENOENT) {
1836                 setup_inline_extent_backref(root, path, iref, parent,
1837                                             root_objectid, owner, offset,
1838                                             refs_to_add, extent_op);
1839                 ret = 0;
1840         }
1841         return ret;
1842 }
1843
1844 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1845                                  struct btrfs_root *root,
1846                                  struct btrfs_path *path,
1847                                  u64 bytenr, u64 parent, u64 root_objectid,
1848                                  u64 owner, u64 offset, int refs_to_add)
1849 {
1850         int ret;
1851         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1852                 BUG_ON(refs_to_add != 1);
1853                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1854                                             parent, root_objectid);
1855         } else {
1856                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1857                                              parent, root_objectid,
1858                                              owner, offset, refs_to_add);
1859         }
1860         return ret;
1861 }
1862
1863 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1864                                  struct btrfs_root *root,
1865                                  struct btrfs_path *path,
1866                                  struct btrfs_extent_inline_ref *iref,
1867                                  int refs_to_drop, int is_data, int *last_ref)
1868 {
1869         int ret = 0;
1870
1871         BUG_ON(!is_data && refs_to_drop != 1);
1872         if (iref) {
1873                 update_inline_extent_backref(root, path, iref,
1874                                              -refs_to_drop, NULL, last_ref);
1875         } else if (is_data) {
1876                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop,
1877                                              last_ref);
1878         } else {
1879                 *last_ref = 1;
1880                 ret = btrfs_del_item(trans, root, path);
1881         }
1882         return ret;
1883 }
1884
1885 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
1886 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1887                                u64 *discarded_bytes)
1888 {
1889         int j, ret = 0;
1890         u64 bytes_left, end;
1891         u64 aligned_start = ALIGN(start, 1 << 9);
1892
1893         if (WARN_ON(start != aligned_start)) {
1894                 len -= aligned_start - start;
1895                 len = round_down(len, 1 << 9);
1896                 start = aligned_start;
1897         }
1898
1899         *discarded_bytes = 0;
1900
1901         if (!len)
1902                 return 0;
1903
1904         end = start + len;
1905         bytes_left = len;
1906
1907         /* Skip any superblocks on this device. */
1908         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1909                 u64 sb_start = btrfs_sb_offset(j);
1910                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1911                 u64 size = sb_start - start;
1912
1913                 if (!in_range(sb_start, start, bytes_left) &&
1914                     !in_range(sb_end, start, bytes_left) &&
1915                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1916                         continue;
1917
1918                 /*
1919                  * Superblock spans beginning of range.  Adjust start and
1920                  * try again.
1921                  */
1922                 if (sb_start <= start) {
1923                         start += sb_end - start;
1924                         if (start > end) {
1925                                 bytes_left = 0;
1926                                 break;
1927                         }
1928                         bytes_left = end - start;
1929                         continue;
1930                 }
1931
1932                 if (size) {
1933                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
1934                                                    GFP_NOFS, 0);
1935                         if (!ret)
1936                                 *discarded_bytes += size;
1937                         else if (ret != -EOPNOTSUPP)
1938                                 return ret;
1939                 }
1940
1941                 start = sb_end;
1942                 if (start > end) {
1943                         bytes_left = 0;
1944                         break;
1945                 }
1946                 bytes_left = end - start;
1947         }
1948
1949         if (bytes_left) {
1950                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
1951                                            GFP_NOFS, 0);
1952                 if (!ret)
1953                         *discarded_bytes += bytes_left;
1954         }
1955         return ret;
1956 }
1957
1958 int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1959                          u64 num_bytes, u64 *actual_bytes)
1960 {
1961         int ret;
1962         u64 discarded_bytes = 0;
1963         struct btrfs_bio *bbio = NULL;
1964
1965
1966         /* Tell the block device(s) that the sectors can be discarded */
1967         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1968                               bytenr, &num_bytes, &bbio, 0);
1969         /* Error condition is -ENOMEM */
1970         if (!ret) {
1971                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1972                 int i;
1973
1974
1975                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1976                         u64 bytes;
1977                         if (!stripe->dev->can_discard)
1978                                 continue;
1979
1980                         ret = btrfs_issue_discard(stripe->dev->bdev,
1981                                                   stripe->physical,
1982                                                   stripe->length,
1983                                                   &bytes);
1984                         if (!ret)
1985                                 discarded_bytes += bytes;
1986                         else if (ret != -EOPNOTSUPP)
1987                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1988
1989                         /*
1990                          * Just in case we get back EOPNOTSUPP for some reason,
1991                          * just ignore the return value so we don't screw up
1992                          * people calling discard_extent.
1993                          */
1994                         ret = 0;
1995                 }
1996                 btrfs_put_bbio(bbio);
1997         }
1998
1999         if (actual_bytes)
2000                 *actual_bytes = discarded_bytes;
2001
2002
2003         if (ret == -EOPNOTSUPP)
2004                 ret = 0;
2005         return ret;
2006 }
2007
2008 /* Can return -ENOMEM */
2009 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2010                          struct btrfs_root *root,
2011                          u64 bytenr, u64 num_bytes, u64 parent,
2012                          u64 root_objectid, u64 owner, u64 offset,
2013                          int no_quota)
2014 {
2015         int ret;
2016         struct btrfs_fs_info *fs_info = root->fs_info;
2017
2018         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2019                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2020
2021         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2022                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2023                                         num_bytes,
2024                                         parent, root_objectid, (int)owner,
2025                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
2026         } else {
2027                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2028                                         num_bytes,
2029                                         parent, root_objectid, owner, offset,
2030                                         BTRFS_ADD_DELAYED_REF, NULL, no_quota);
2031         }
2032         return ret;
2033 }
2034
2035 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2036                                   struct btrfs_root *root,
2037                                   struct btrfs_delayed_ref_node *node,
2038                                   u64 parent, u64 root_objectid,
2039                                   u64 owner, u64 offset, int refs_to_add,
2040                                   struct btrfs_delayed_extent_op *extent_op)
2041 {
2042         struct btrfs_fs_info *fs_info = root->fs_info;
2043         struct btrfs_path *path;
2044         struct extent_buffer *leaf;
2045         struct btrfs_extent_item *item;
2046         struct btrfs_key key;
2047         u64 bytenr = node->bytenr;
2048         u64 num_bytes = node->num_bytes;
2049         u64 refs;
2050         int ret;
2051         int no_quota = node->no_quota;
2052
2053         path = btrfs_alloc_path();
2054         if (!path)
2055                 return -ENOMEM;
2056
2057         if (!is_fstree(root_objectid) || !root->fs_info->quota_enabled)
2058                 no_quota = 1;
2059
2060         path->reada = 1;
2061         path->leave_spinning = 1;
2062         /* this will setup the path even if it fails to insert the back ref */
2063         ret = insert_inline_extent_backref(trans, fs_info->extent_root, path,
2064                                            bytenr, num_bytes, parent,
2065                                            root_objectid, owner, offset,
2066                                            refs_to_add, extent_op);
2067         if ((ret < 0 && ret != -EAGAIN) || !ret)
2068                 goto out;
2069
2070         /*
2071          * Ok we had -EAGAIN which means we didn't have space to insert and
2072          * inline extent ref, so just update the reference count and add a
2073          * normal backref.
2074          */
2075         leaf = path->nodes[0];
2076         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2077         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2078         refs = btrfs_extent_refs(leaf, item);
2079         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2080         if (extent_op)
2081                 __run_delayed_extent_op(extent_op, leaf, item);
2082
2083         btrfs_mark_buffer_dirty(leaf);
2084         btrfs_release_path(path);
2085
2086         path->reada = 1;
2087         path->leave_spinning = 1;
2088         /* now insert the actual backref */
2089         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2090                                     path, bytenr, parent, root_objectid,
2091                                     owner, offset, refs_to_add);
2092         if (ret)
2093                 btrfs_abort_transaction(trans, root, ret);
2094 out:
2095         btrfs_free_path(path);
2096         return ret;
2097 }
2098
2099 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2100                                 struct btrfs_root *root,
2101                                 struct btrfs_delayed_ref_node *node,
2102                                 struct btrfs_delayed_extent_op *extent_op,
2103                                 int insert_reserved)
2104 {
2105         int ret = 0;
2106         struct btrfs_delayed_data_ref *ref;
2107         struct btrfs_key ins;
2108         u64 parent = 0;
2109         u64 ref_root = 0;
2110         u64 flags = 0;
2111
2112         ins.objectid = node->bytenr;
2113         ins.offset = node->num_bytes;
2114         ins.type = BTRFS_EXTENT_ITEM_KEY;
2115
2116         ref = btrfs_delayed_node_to_data_ref(node);
2117         trace_run_delayed_data_ref(node, ref, node->action);
2118
2119         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2120                 parent = ref->parent;
2121         ref_root = ref->root;
2122
2123         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2124                 if (extent_op)
2125                         flags |= extent_op->flags_to_set;
2126                 ret = alloc_reserved_file_extent(trans, root,
2127                                                  parent, ref_root, flags,
2128                                                  ref->objectid, ref->offset,
2129                                                  &ins, node->ref_mod);
2130         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2131                 ret = __btrfs_inc_extent_ref(trans, root, node, parent,
2132                                              ref_root, ref->objectid,
2133                                              ref->offset, node->ref_mod,
2134                                              extent_op);
2135         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2136                 ret = __btrfs_free_extent(trans, root, node, parent,
2137                                           ref_root, ref->objectid,
2138                                           ref->offset, node->ref_mod,
2139                                           extent_op);
2140         } else {
2141                 BUG();
2142         }
2143         return ret;
2144 }
2145
2146 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2147                                     struct extent_buffer *leaf,
2148                                     struct btrfs_extent_item *ei)
2149 {
2150         u64 flags = btrfs_extent_flags(leaf, ei);
2151         if (extent_op->update_flags) {
2152                 flags |= extent_op->flags_to_set;
2153                 btrfs_set_extent_flags(leaf, ei, flags);
2154         }
2155
2156         if (extent_op->update_key) {
2157                 struct btrfs_tree_block_info *bi;
2158                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2159                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2160                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2161         }
2162 }
2163
2164 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2165                                  struct btrfs_root *root,
2166                                  struct btrfs_delayed_ref_node *node,
2167                                  struct btrfs_delayed_extent_op *extent_op)
2168 {
2169         struct btrfs_key key;
2170         struct btrfs_path *path;
2171         struct btrfs_extent_item *ei;
2172         struct extent_buffer *leaf;
2173         u32 item_size;
2174         int ret;
2175         int err = 0;
2176         int metadata = !extent_op->is_data;
2177
2178         if (trans->aborted)
2179                 return 0;
2180
2181         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2182                 metadata = 0;
2183
2184         path = btrfs_alloc_path();
2185         if (!path)
2186                 return -ENOMEM;
2187
2188         key.objectid = node->bytenr;
2189
2190         if (metadata) {
2191                 key.type = BTRFS_METADATA_ITEM_KEY;
2192                 key.offset = extent_op->level;
2193         } else {
2194                 key.type = BTRFS_EXTENT_ITEM_KEY;
2195                 key.offset = node->num_bytes;
2196         }
2197
2198 again:
2199         path->reada = 1;
2200         path->leave_spinning = 1;
2201         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2202                                 path, 0, 1);
2203         if (ret < 0) {
2204                 err = ret;
2205                 goto out;
2206         }
2207         if (ret > 0) {
2208                 if (metadata) {
2209                         if (path->slots[0] > 0) {
2210                                 path->slots[0]--;
2211                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2212                                                       path->slots[0]);
2213                                 if (key.objectid == node->bytenr &&
2214                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2215                                     key.offset == node->num_bytes)
2216                                         ret = 0;
2217                         }
2218                         if (ret > 0) {
2219                                 btrfs_release_path(path);
2220                                 metadata = 0;
2221
2222                                 key.objectid = node->bytenr;
2223                                 key.offset = node->num_bytes;
2224                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2225                                 goto again;
2226                         }
2227                 } else {
2228                         err = -EIO;
2229                         goto out;
2230                 }
2231         }
2232
2233         leaf = path->nodes[0];
2234         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2235 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2236         if (item_size < sizeof(*ei)) {
2237                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2238                                              path, (u64)-1, 0);
2239                 if (ret < 0) {
2240                         err = ret;
2241                         goto out;
2242                 }
2243                 leaf = path->nodes[0];
2244                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2245         }
2246 #endif
2247         BUG_ON(item_size < sizeof(*ei));
2248         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2249         __run_delayed_extent_op(extent_op, leaf, ei);
2250
2251         btrfs_mark_buffer_dirty(leaf);
2252 out:
2253         btrfs_free_path(path);
2254         return err;
2255 }
2256
2257 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2258                                 struct btrfs_root *root,
2259                                 struct btrfs_delayed_ref_node *node,
2260                                 struct btrfs_delayed_extent_op *extent_op,
2261                                 int insert_reserved)
2262 {
2263         int ret = 0;
2264         struct btrfs_delayed_tree_ref *ref;
2265         struct btrfs_key ins;
2266         u64 parent = 0;
2267         u64 ref_root = 0;
2268         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2269                                                  SKINNY_METADATA);
2270
2271         ref = btrfs_delayed_node_to_tree_ref(node);
2272         trace_run_delayed_tree_ref(node, ref, node->action);
2273
2274         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2275                 parent = ref->parent;
2276         ref_root = ref->root;
2277
2278         ins.objectid = node->bytenr;
2279         if (skinny_metadata) {
2280                 ins.offset = ref->level;
2281                 ins.type = BTRFS_METADATA_ITEM_KEY;
2282         } else {
2283                 ins.offset = node->num_bytes;
2284                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2285         }
2286
2287         BUG_ON(node->ref_mod != 1);
2288         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2289                 BUG_ON(!extent_op || !extent_op->update_flags);
2290                 ret = alloc_reserved_tree_block(trans, root,
2291                                                 parent, ref_root,
2292                                                 extent_op->flags_to_set,
2293                                                 &extent_op->key,
2294                                                 ref->level, &ins,
2295                                                 node->no_quota);
2296         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2297                 ret = __btrfs_inc_extent_ref(trans, root, node,
2298                                              parent, ref_root,
2299                                              ref->level, 0, 1,
2300                                              extent_op);
2301         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2302                 ret = __btrfs_free_extent(trans, root, node,
2303                                           parent, ref_root,
2304                                           ref->level, 0, 1, extent_op);
2305         } else {
2306                 BUG();
2307         }
2308         return ret;
2309 }
2310
2311 /* helper function to actually process a single delayed ref entry */
2312 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2313                                struct btrfs_root *root,
2314                                struct btrfs_delayed_ref_node *node,
2315                                struct btrfs_delayed_extent_op *extent_op,
2316                                int insert_reserved)
2317 {
2318         int ret = 0;
2319
2320         if (trans->aborted) {
2321                 if (insert_reserved)
2322                         btrfs_pin_extent(root, node->bytenr,
2323                                          node->num_bytes, 1);
2324                 return 0;
2325         }
2326
2327         if (btrfs_delayed_ref_is_head(node)) {
2328                 struct btrfs_delayed_ref_head *head;
2329                 /*
2330                  * we've hit the end of the chain and we were supposed
2331                  * to insert this extent into the tree.  But, it got
2332                  * deleted before we ever needed to insert it, so all
2333                  * we have to do is clean up the accounting
2334                  */
2335                 BUG_ON(extent_op);
2336                 head = btrfs_delayed_node_to_head(node);
2337                 trace_run_delayed_ref_head(node, head, node->action);
2338
2339                 if (insert_reserved) {
2340                         btrfs_pin_extent(root, node->bytenr,
2341                                          node->num_bytes, 1);
2342                         if (head->is_data) {
2343                                 ret = btrfs_del_csums(trans, root,
2344                                                       node->bytenr,
2345                                                       node->num_bytes);
2346                         }
2347                 }
2348
2349                 /* Also free its reserved qgroup space */
2350                 btrfs_qgroup_free_delayed_ref(root->fs_info,
2351                                               head->qgroup_ref_root,
2352                                               head->qgroup_reserved);
2353                 return ret;
2354         }
2355
2356         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2357             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2358                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2359                                            insert_reserved);
2360         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2361                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2362                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2363                                            insert_reserved);
2364         else
2365                 BUG();
2366         return ret;
2367 }
2368
2369 static inline struct btrfs_delayed_ref_node *
2370 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2371 {
2372         struct btrfs_delayed_ref_node *ref;
2373
2374         if (list_empty(&head->ref_list))
2375                 return NULL;
2376
2377         /*
2378          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2379          * This is to prevent a ref count from going down to zero, which deletes
2380          * the extent item from the extent tree, when there still are references
2381          * to add, which would fail because they would not find the extent item.
2382          */
2383         list_for_each_entry(ref, &head->ref_list, list) {
2384                 if (ref->action == BTRFS_ADD_DELAYED_REF)
2385                         return ref;
2386         }
2387
2388         return list_entry(head->ref_list.next, struct btrfs_delayed_ref_node,
2389                           list);
2390 }
2391
2392 /*
2393  * Returns 0 on success or if called with an already aborted transaction.
2394  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2395  */
2396 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2397                                              struct btrfs_root *root,
2398                                              unsigned long nr)
2399 {
2400         struct btrfs_delayed_ref_root *delayed_refs;
2401         struct btrfs_delayed_ref_node *ref;
2402         struct btrfs_delayed_ref_head *locked_ref = NULL;
2403         struct btrfs_delayed_extent_op *extent_op;
2404         struct btrfs_fs_info *fs_info = root->fs_info;
2405         ktime_t start = ktime_get();
2406         int ret;
2407         unsigned long count = 0;
2408         unsigned long actual_count = 0;
2409         int must_insert_reserved = 0;
2410
2411         delayed_refs = &trans->transaction->delayed_refs;
2412         while (1) {
2413                 if (!locked_ref) {
2414                         if (count >= nr)
2415                                 break;
2416
2417                         spin_lock(&delayed_refs->lock);
2418                         locked_ref = btrfs_select_ref_head(trans);
2419                         if (!locked_ref) {
2420                                 spin_unlock(&delayed_refs->lock);
2421                                 break;
2422                         }
2423
2424                         /* grab the lock that says we are going to process
2425                          * all the refs for this head */
2426                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2427                         spin_unlock(&delayed_refs->lock);
2428                         /*
2429                          * we may have dropped the spin lock to get the head
2430                          * mutex lock, and that might have given someone else
2431                          * time to free the head.  If that's true, it has been
2432                          * removed from our list and we can move on.
2433                          */
2434                         if (ret == -EAGAIN) {
2435                                 locked_ref = NULL;
2436                                 count++;
2437                                 continue;
2438                         }
2439                 }
2440
2441                 spin_lock(&locked_ref->lock);
2442
2443                 /*
2444                  * locked_ref is the head node, so we have to go one
2445                  * node back for any delayed ref updates
2446                  */
2447                 ref = select_delayed_ref(locked_ref);
2448
2449                 if (ref && ref->seq &&
2450                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2451                         spin_unlock(&locked_ref->lock);
2452                         btrfs_delayed_ref_unlock(locked_ref);
2453                         spin_lock(&delayed_refs->lock);
2454                         locked_ref->processing = 0;
2455                         delayed_refs->num_heads_ready++;
2456                         spin_unlock(&delayed_refs->lock);
2457                         locked_ref = NULL;
2458                         cond_resched();
2459                         count++;
2460                         continue;
2461                 }
2462
2463                 /*
2464                  * record the must insert reserved flag before we
2465                  * drop the spin lock.
2466                  */
2467                 must_insert_reserved = locked_ref->must_insert_reserved;
2468                 locked_ref->must_insert_reserved = 0;
2469
2470                 extent_op = locked_ref->extent_op;
2471                 locked_ref->extent_op = NULL;
2472
2473                 if (!ref) {
2474
2475
2476                         /* All delayed refs have been processed, Go ahead
2477                          * and send the head node to run_one_delayed_ref,
2478                          * so that any accounting fixes can happen
2479                          */
2480                         ref = &locked_ref->node;
2481
2482                         if (extent_op && must_insert_reserved) {
2483                                 btrfs_free_delayed_extent_op(extent_op);
2484                                 extent_op = NULL;
2485                         }
2486
2487                         if (extent_op) {
2488                                 spin_unlock(&locked_ref->lock);
2489                                 ret = run_delayed_extent_op(trans, root,
2490                                                             ref, extent_op);
2491                                 btrfs_free_delayed_extent_op(extent_op);
2492
2493                                 if (ret) {
2494                                         /*
2495                                          * Need to reset must_insert_reserved if
2496                                          * there was an error so the abort stuff
2497                                          * can cleanup the reserved space
2498                                          * properly.
2499                                          */
2500                                         if (must_insert_reserved)
2501                                                 locked_ref->must_insert_reserved = 1;
2502                                         locked_ref->processing = 0;
2503                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2504                                         btrfs_delayed_ref_unlock(locked_ref);
2505                                         return ret;
2506                                 }
2507                                 continue;
2508                         }
2509
2510                         /*
2511                          * Need to drop our head ref lock and re-aqcuire the
2512                          * delayed ref lock and then re-check to make sure
2513                          * nobody got added.
2514                          */
2515                         spin_unlock(&locked_ref->lock);
2516                         spin_lock(&delayed_refs->lock);
2517                         spin_lock(&locked_ref->lock);
2518                         if (!list_empty(&locked_ref->ref_list) ||
2519                             locked_ref->extent_op) {
2520                                 spin_unlock(&locked_ref->lock);
2521                                 spin_unlock(&delayed_refs->lock);
2522                                 continue;
2523                         }
2524                         ref->in_tree = 0;
2525                         delayed_refs->num_heads--;
2526                         rb_erase(&locked_ref->href_node,
2527                                  &delayed_refs->href_root);
2528                         spin_unlock(&delayed_refs->lock);
2529                 } else {
2530                         actual_count++;
2531                         ref->in_tree = 0;
2532                         list_del(&ref->list);
2533                 }
2534                 atomic_dec(&delayed_refs->num_entries);
2535
2536                 if (!btrfs_delayed_ref_is_head(ref)) {
2537                         /*
2538                          * when we play the delayed ref, also correct the
2539                          * ref_mod on head
2540                          */
2541                         switch (ref->action) {
2542                         case BTRFS_ADD_DELAYED_REF:
2543                         case BTRFS_ADD_DELAYED_EXTENT:
2544                                 locked_ref->node.ref_mod -= ref->ref_mod;
2545                                 break;
2546                         case BTRFS_DROP_DELAYED_REF:
2547                                 locked_ref->node.ref_mod += ref->ref_mod;
2548                                 break;
2549                         default:
2550                                 WARN_ON(1);
2551                         }
2552                 }
2553                 spin_unlock(&locked_ref->lock);
2554
2555                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2556                                           must_insert_reserved);
2557
2558                 btrfs_free_delayed_extent_op(extent_op);
2559                 if (ret) {
2560                         locked_ref->processing = 0;
2561                         btrfs_delayed_ref_unlock(locked_ref);
2562                         btrfs_put_delayed_ref(ref);
2563                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2564                         return ret;
2565                 }
2566
2567                 /*
2568                  * If this node is a head, that means all the refs in this head
2569                  * have been dealt with, and we will pick the next head to deal
2570                  * with, so we must unlock the head and drop it from the cluster
2571                  * list before we release it.
2572                  */
2573                 if (btrfs_delayed_ref_is_head(ref)) {
2574                         if (locked_ref->is_data &&
2575                             locked_ref->total_ref_mod < 0) {
2576                                 spin_lock(&delayed_refs->lock);
2577                                 delayed_refs->pending_csums -= ref->num_bytes;
2578                                 spin_unlock(&delayed_refs->lock);
2579                         }
2580                         btrfs_delayed_ref_unlock(locked_ref);
2581                         locked_ref = NULL;
2582                 }
2583                 btrfs_put_delayed_ref(ref);
2584                 count++;
2585                 cond_resched();
2586         }
2587
2588         /*
2589          * We don't want to include ref heads since we can have empty ref heads
2590          * and those will drastically skew our runtime down since we just do
2591          * accounting, no actual extent tree updates.
2592          */
2593         if (actual_count > 0) {
2594                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2595                 u64 avg;
2596
2597                 /*
2598                  * We weigh the current average higher than our current runtime
2599                  * to avoid large swings in the average.
2600                  */
2601                 spin_lock(&delayed_refs->lock);
2602                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2603                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2604                 spin_unlock(&delayed_refs->lock);
2605         }
2606         return 0;
2607 }
2608
2609 #ifdef SCRAMBLE_DELAYED_REFS
2610 /*
2611  * Normally delayed refs get processed in ascending bytenr order. This
2612  * correlates in most cases to the order added. To expose dependencies on this
2613  * order, we start to process the tree in the middle instead of the beginning
2614  */
2615 static u64 find_middle(struct rb_root *root)
2616 {
2617         struct rb_node *n = root->rb_node;
2618         struct btrfs_delayed_ref_node *entry;
2619         int alt = 1;
2620         u64 middle;
2621         u64 first = 0, last = 0;
2622
2623         n = rb_first(root);
2624         if (n) {
2625                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2626                 first = entry->bytenr;
2627         }
2628         n = rb_last(root);
2629         if (n) {
2630                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2631                 last = entry->bytenr;
2632         }
2633         n = root->rb_node;
2634
2635         while (n) {
2636                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2637                 WARN_ON(!entry->in_tree);
2638
2639                 middle = entry->bytenr;
2640
2641                 if (alt)
2642                         n = n->rb_left;
2643                 else
2644                         n = n->rb_right;
2645
2646                 alt = 1 - alt;
2647         }
2648         return middle;
2649 }
2650 #endif
2651
2652 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2653 {
2654         u64 num_bytes;
2655
2656         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2657                              sizeof(struct btrfs_extent_inline_ref));
2658         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2659                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2660
2661         /*
2662          * We don't ever fill up leaves all the way so multiply by 2 just to be
2663          * closer to what we're really going to want to ouse.
2664          */
2665         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2666 }
2667
2668 /*
2669  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2670  * would require to store the csums for that many bytes.
2671  */
2672 u64 btrfs_csum_bytes_to_leaves(struct btrfs_root *root, u64 csum_bytes)
2673 {
2674         u64 csum_size;
2675         u64 num_csums_per_leaf;
2676         u64 num_csums;
2677
2678         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
2679         num_csums_per_leaf = div64_u64(csum_size,
2680                         (u64)btrfs_super_csum_size(root->fs_info->super_copy));
2681         num_csums = div64_u64(csum_bytes, root->sectorsize);
2682         num_csums += num_csums_per_leaf - 1;
2683         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2684         return num_csums;
2685 }
2686
2687 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2688                                        struct btrfs_root *root)
2689 {
2690         struct btrfs_block_rsv *global_rsv;
2691         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2692         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2693         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2694         u64 num_bytes, num_dirty_bgs_bytes;
2695         int ret = 0;
2696
2697         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2698         num_heads = heads_to_leaves(root, num_heads);
2699         if (num_heads > 1)
2700                 num_bytes += (num_heads - 1) * root->nodesize;
2701         num_bytes <<= 1;
2702         num_bytes += btrfs_csum_bytes_to_leaves(root, csum_bytes) * root->nodesize;
2703         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(root,
2704                                                              num_dirty_bgs);
2705         global_rsv = &root->fs_info->global_block_rsv;
2706
2707         /*
2708          * If we can't allocate any more chunks lets make sure we have _lots_ of
2709          * wiggle room since running delayed refs can create more delayed refs.
2710          */
2711         if (global_rsv->space_info->full) {
2712                 num_dirty_bgs_bytes <<= 1;
2713                 num_bytes <<= 1;
2714         }
2715
2716         spin_lock(&global_rsv->lock);
2717         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2718                 ret = 1;
2719         spin_unlock(&global_rsv->lock);
2720         return ret;
2721 }
2722
2723 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2724                                        struct btrfs_root *root)
2725 {
2726         struct btrfs_fs_info *fs_info = root->fs_info;
2727         u64 num_entries =
2728                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2729         u64 avg_runtime;
2730         u64 val;
2731
2732         smp_mb();
2733         avg_runtime = fs_info->avg_delayed_ref_runtime;
2734         val = num_entries * avg_runtime;
2735         if (num_entries * avg_runtime >= NSEC_PER_SEC)
2736                 return 1;
2737         if (val >= NSEC_PER_SEC / 2)
2738                 return 2;
2739
2740         return btrfs_check_space_for_delayed_refs(trans, root);
2741 }
2742
2743 struct async_delayed_refs {
2744         struct btrfs_root *root;
2745         int count;
2746         int error;
2747         int sync;
2748         struct completion wait;
2749         struct btrfs_work work;
2750 };
2751
2752 static void delayed_ref_async_start(struct btrfs_work *work)
2753 {
2754         struct async_delayed_refs *async;
2755         struct btrfs_trans_handle *trans;
2756         int ret;
2757
2758         async = container_of(work, struct async_delayed_refs, work);
2759
2760         trans = btrfs_join_transaction(async->root);
2761         if (IS_ERR(trans)) {
2762                 async->error = PTR_ERR(trans);
2763                 goto done;
2764         }
2765
2766         /*
2767          * trans->sync means that when we call end_transaciton, we won't
2768          * wait on delayed refs
2769          */
2770         trans->sync = true;
2771         ret = btrfs_run_delayed_refs(trans, async->root, async->count);
2772         if (ret)
2773                 async->error = ret;
2774
2775         ret = btrfs_end_transaction(trans, async->root);
2776         if (ret && !async->error)
2777                 async->error = ret;
2778 done:
2779         if (async->sync)
2780                 complete(&async->wait);
2781         else
2782                 kfree(async);
2783 }
2784
2785 int btrfs_async_run_delayed_refs(struct btrfs_root *root,
2786                                  unsigned long count, int wait)
2787 {
2788         struct async_delayed_refs *async;
2789         int ret;
2790
2791         async = kmalloc(sizeof(*async), GFP_NOFS);
2792         if (!async)
2793                 return -ENOMEM;
2794
2795         async->root = root->fs_info->tree_root;
2796         async->count = count;
2797         async->error = 0;
2798         if (wait)
2799                 async->sync = 1;
2800         else
2801                 async->sync = 0;
2802         init_completion(&async->wait);
2803
2804         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
2805                         delayed_ref_async_start, NULL, NULL);
2806
2807         btrfs_queue_work(root->fs_info->extent_workers, &async->work);
2808
2809         if (wait) {
2810                 wait_for_completion(&async->wait);
2811                 ret = async->error;
2812                 kfree(async);
2813                 return ret;
2814         }
2815         return 0;
2816 }
2817
2818 /*
2819  * this starts processing the delayed reference count updates and
2820  * extent insertions we have queued up so far.  count can be
2821  * 0, which means to process everything in the tree at the start
2822  * of the run (but not newly added entries), or it can be some target
2823  * number you'd like to process.
2824  *
2825  * Returns 0 on success or if called with an aborted transaction
2826  * Returns <0 on error and aborts the transaction
2827  */
2828 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2829                            struct btrfs_root *root, unsigned long count)
2830 {
2831         struct rb_node *node;
2832         struct btrfs_delayed_ref_root *delayed_refs;
2833         struct btrfs_delayed_ref_head *head;
2834         int ret;
2835         int run_all = count == (unsigned long)-1;
2836         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
2837
2838         /* We'll clean this up in btrfs_cleanup_transaction */
2839         if (trans->aborted)
2840                 return 0;
2841
2842         if (root == root->fs_info->extent_root)
2843                 root = root->fs_info->tree_root;
2844
2845         delayed_refs = &trans->transaction->delayed_refs;
2846         if (count == 0)
2847                 count = atomic_read(&delayed_refs->num_entries) * 2;
2848
2849 again:
2850 #ifdef SCRAMBLE_DELAYED_REFS
2851         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2852 #endif
2853         trans->can_flush_pending_bgs = false;
2854         ret = __btrfs_run_delayed_refs(trans, root, count);
2855         if (ret < 0) {
2856                 btrfs_abort_transaction(trans, root, ret);
2857                 return ret;
2858         }
2859
2860         if (run_all) {
2861                 if (!list_empty(&trans->new_bgs))
2862                         btrfs_create_pending_block_groups(trans, root);
2863
2864                 spin_lock(&delayed_refs->lock);
2865                 node = rb_first(&delayed_refs->href_root);
2866                 if (!node) {
2867                         spin_unlock(&delayed_refs->lock);
2868                         goto out;
2869                 }
2870                 count = (unsigned long)-1;
2871
2872                 while (node) {
2873                         head = rb_entry(node, struct btrfs_delayed_ref_head,
2874                                         href_node);
2875                         if (btrfs_delayed_ref_is_head(&head->node)) {
2876                                 struct btrfs_delayed_ref_node *ref;
2877
2878                                 ref = &head->node;
2879                                 atomic_inc(&ref->refs);
2880
2881                                 spin_unlock(&delayed_refs->lock);
2882                                 /*
2883                                  * Mutex was contended, block until it's
2884                                  * released and try again
2885                                  */
2886                                 mutex_lock(&head->mutex);
2887                                 mutex_unlock(&head->mutex);
2888
2889                                 btrfs_put_delayed_ref(ref);
2890                                 cond_resched();
2891                                 goto again;
2892                         } else {
2893                                 WARN_ON(1);
2894                         }
2895                         node = rb_next(node);
2896                 }
2897                 spin_unlock(&delayed_refs->lock);
2898                 cond_resched();
2899                 goto again;
2900         }
2901 out:
2902         assert_qgroups_uptodate(trans);
2903         trans->can_flush_pending_bgs = can_flush_pending_bgs;
2904         return 0;
2905 }
2906
2907 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2908                                 struct btrfs_root *root,
2909                                 u64 bytenr, u64 num_bytes, u64 flags,
2910                                 int level, int is_data)
2911 {
2912         struct btrfs_delayed_extent_op *extent_op;
2913         int ret;
2914
2915         extent_op = btrfs_alloc_delayed_extent_op();
2916         if (!extent_op)
2917                 return -ENOMEM;
2918
2919         extent_op->flags_to_set = flags;
2920         extent_op->update_flags = 1;
2921         extent_op->update_key = 0;
2922         extent_op->is_data = is_data ? 1 : 0;
2923         extent_op->level = level;
2924
2925         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2926                                           num_bytes, extent_op);
2927         if (ret)
2928                 btrfs_free_delayed_extent_op(extent_op);
2929         return ret;
2930 }
2931
2932 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2933                                       struct btrfs_root *root,
2934                                       struct btrfs_path *path,
2935                                       u64 objectid, u64 offset, u64 bytenr)
2936 {
2937         struct btrfs_delayed_ref_head *head;
2938         struct btrfs_delayed_ref_node *ref;
2939         struct btrfs_delayed_data_ref *data_ref;
2940         struct btrfs_delayed_ref_root *delayed_refs;
2941         int ret = 0;
2942
2943         delayed_refs = &trans->transaction->delayed_refs;
2944         spin_lock(&delayed_refs->lock);
2945         head = btrfs_find_delayed_ref_head(trans, bytenr);
2946         if (!head) {
2947                 spin_unlock(&delayed_refs->lock);
2948                 return 0;
2949         }
2950
2951         if (!mutex_trylock(&head->mutex)) {
2952                 atomic_inc(&head->node.refs);
2953                 spin_unlock(&delayed_refs->lock);
2954
2955                 btrfs_release_path(path);
2956
2957                 /*
2958                  * Mutex was contended, block until it's released and let
2959                  * caller try again
2960                  */
2961                 mutex_lock(&head->mutex);
2962                 mutex_unlock(&head->mutex);
2963                 btrfs_put_delayed_ref(&head->node);
2964                 return -EAGAIN;
2965         }
2966         spin_unlock(&delayed_refs->lock);
2967
2968         spin_lock(&head->lock);
2969         list_for_each_entry(ref, &head->ref_list, list) {
2970                 /* If it's a shared ref we know a cross reference exists */
2971                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2972                         ret = 1;
2973                         break;
2974                 }
2975
2976                 data_ref = btrfs_delayed_node_to_data_ref(ref);
2977
2978                 /*
2979                  * If our ref doesn't match the one we're currently looking at
2980                  * then we have a cross reference.
2981                  */
2982                 if (data_ref->root != root->root_key.objectid ||
2983                     data_ref->objectid != objectid ||
2984                     data_ref->offset != offset) {
2985                         ret = 1;
2986                         break;
2987                 }
2988         }
2989         spin_unlock(&head->lock);
2990         mutex_unlock(&head->mutex);
2991         return ret;
2992 }
2993
2994 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2995                                         struct btrfs_root *root,
2996                                         struct btrfs_path *path,
2997                                         u64 objectid, u64 offset, u64 bytenr)
2998 {
2999         struct btrfs_root *extent_root = root->fs_info->extent_root;
3000         struct extent_buffer *leaf;
3001         struct btrfs_extent_data_ref *ref;
3002         struct btrfs_extent_inline_ref *iref;
3003         struct btrfs_extent_item *ei;
3004         struct btrfs_key key;
3005         u32 item_size;
3006         int ret;
3007
3008         key.objectid = bytenr;
3009         key.offset = (u64)-1;
3010         key.type = BTRFS_EXTENT_ITEM_KEY;
3011
3012         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3013         if (ret < 0)
3014                 goto out;
3015         BUG_ON(ret == 0); /* Corruption */
3016
3017         ret = -ENOENT;
3018         if (path->slots[0] == 0)
3019                 goto out;
3020
3021         path->slots[0]--;
3022         leaf = path->nodes[0];
3023         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3024
3025         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3026                 goto out;
3027
3028         ret = 1;
3029         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3030 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3031         if (item_size < sizeof(*ei)) {
3032                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3033                 goto out;
3034         }
3035 #endif
3036         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3037
3038         if (item_size != sizeof(*ei) +
3039             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3040                 goto out;
3041
3042         if (btrfs_extent_generation(leaf, ei) <=
3043             btrfs_root_last_snapshot(&root->root_item))
3044                 goto out;
3045
3046         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3047         if (btrfs_extent_inline_ref_type(leaf, iref) !=
3048             BTRFS_EXTENT_DATA_REF_KEY)
3049                 goto out;
3050
3051         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3052         if (btrfs_extent_refs(leaf, ei) !=
3053             btrfs_extent_data_ref_count(leaf, ref) ||
3054             btrfs_extent_data_ref_root(leaf, ref) !=
3055             root->root_key.objectid ||
3056             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3057             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3058                 goto out;
3059
3060         ret = 0;
3061 out:
3062         return ret;
3063 }
3064
3065 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
3066                           struct btrfs_root *root,
3067                           u64 objectid, u64 offset, u64 bytenr)
3068 {
3069         struct btrfs_path *path;
3070         int ret;
3071         int ret2;
3072
3073         path = btrfs_alloc_path();
3074         if (!path)
3075                 return -ENOENT;
3076
3077         do {
3078                 ret = check_committed_ref(trans, root, path, objectid,
3079                                           offset, bytenr);
3080                 if (ret && ret != -ENOENT)
3081                         goto out;
3082
3083                 ret2 = check_delayed_ref(trans, root, path, objectid,
3084                                          offset, bytenr);
3085         } while (ret2 == -EAGAIN);
3086
3087         if (ret2 && ret2 != -ENOENT) {
3088                 ret = ret2;
3089                 goto out;
3090         }
3091
3092         if (ret != -ENOENT || ret2 != -ENOENT)
3093                 ret = 0;
3094 out:
3095         btrfs_free_path(path);
3096         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3097                 WARN_ON(ret > 0);
3098         return ret;
3099 }
3100
3101 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3102                            struct btrfs_root *root,
3103                            struct extent_buffer *buf,
3104                            int full_backref, int inc)
3105 {
3106         u64 bytenr;
3107         u64 num_bytes;
3108         u64 parent;
3109         u64 ref_root;
3110         u32 nritems;
3111         struct btrfs_key key;
3112         struct btrfs_file_extent_item *fi;
3113         int i;
3114         int level;
3115         int ret = 0;
3116         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3117                             u64, u64, u64, u64, u64, u64, int);
3118
3119
3120         if (btrfs_test_is_dummy_root(root))
3121                 return 0;
3122
3123         ref_root = btrfs_header_owner(buf);
3124         nritems = btrfs_header_nritems(buf);
3125         level = btrfs_header_level(buf);
3126
3127         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3128                 return 0;
3129
3130         if (inc)
3131                 process_func = btrfs_inc_extent_ref;
3132         else
3133                 process_func = btrfs_free_extent;
3134
3135         if (full_backref)
3136                 parent = buf->start;
3137         else
3138                 parent = 0;
3139
3140         for (i = 0; i < nritems; i++) {
3141                 if (level == 0) {
3142                         btrfs_item_key_to_cpu(buf, &key, i);
3143                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3144                                 continue;
3145                         fi = btrfs_item_ptr(buf, i,
3146                                             struct btrfs_file_extent_item);
3147                         if (btrfs_file_extent_type(buf, fi) ==
3148                             BTRFS_FILE_EXTENT_INLINE)
3149                                 continue;
3150                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3151                         if (bytenr == 0)
3152                                 continue;
3153
3154                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3155                         key.offset -= btrfs_file_extent_offset(buf, fi);
3156                         ret = process_func(trans, root, bytenr, num_bytes,
3157                                            parent, ref_root, key.objectid,
3158                                            key.offset, 1);
3159                         if (ret)
3160                                 goto fail;
3161                 } else {
3162                         bytenr = btrfs_node_blockptr(buf, i);
3163                         num_bytes = root->nodesize;
3164                         ret = process_func(trans, root, bytenr, num_bytes,
3165                                            parent, ref_root, level - 1, 0,
3166                                            1);
3167                         if (ret)
3168                                 goto fail;
3169                 }
3170         }
3171         return 0;
3172 fail:
3173         return ret;
3174 }
3175
3176 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3177                   struct extent_buffer *buf, int full_backref)
3178 {
3179         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3180 }
3181
3182 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3183                   struct extent_buffer *buf, int full_backref)
3184 {
3185         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3186 }
3187
3188 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3189                                  struct btrfs_root *root,
3190                                  struct btrfs_path *path,
3191                                  struct btrfs_block_group_cache *cache)
3192 {
3193         int ret;
3194         struct btrfs_root *extent_root = root->fs_info->extent_root;
3195         unsigned long bi;
3196         struct extent_buffer *leaf;
3197
3198         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3199         if (ret) {
3200                 if (ret > 0)
3201                         ret = -ENOENT;
3202                 goto fail;
3203         }
3204
3205         leaf = path->nodes[0];
3206         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3207         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3208         btrfs_mark_buffer_dirty(leaf);
3209 fail:
3210         btrfs_release_path(path);
3211         return ret;
3212
3213 }
3214
3215 static struct btrfs_block_group_cache *
3216 next_block_group(struct btrfs_root *root,
3217                  struct btrfs_block_group_cache *cache)
3218 {
3219         struct rb_node *node;
3220
3221         spin_lock(&root->fs_info->block_group_cache_lock);
3222
3223         /* If our block group was removed, we need a full search. */
3224         if (RB_EMPTY_NODE(&cache->cache_node)) {
3225                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3226
3227                 spin_unlock(&root->fs_info->block_group_cache_lock);
3228                 btrfs_put_block_group(cache);
3229                 cache = btrfs_lookup_first_block_group(root->fs_info,
3230                                                        next_bytenr);
3231                 return cache;
3232         }
3233         node = rb_next(&cache->cache_node);
3234         btrfs_put_block_group(cache);
3235         if (node) {
3236                 cache = rb_entry(node, struct btrfs_block_group_cache,
3237                                  cache_node);
3238                 btrfs_get_block_group(cache);
3239         } else
3240                 cache = NULL;
3241         spin_unlock(&root->fs_info->block_group_cache_lock);
3242         return cache;
3243 }
3244
3245 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3246                             struct btrfs_trans_handle *trans,
3247                             struct btrfs_path *path)
3248 {
3249         struct btrfs_root *root = block_group->fs_info->tree_root;
3250         struct inode *inode = NULL;
3251         u64 alloc_hint = 0;
3252         int dcs = BTRFS_DC_ERROR;
3253         u64 num_pages = 0;
3254         int retries = 0;
3255         int ret = 0;
3256
3257         /*
3258          * If this block group is smaller than 100 megs don't bother caching the
3259          * block group.
3260          */
3261         if (block_group->key.offset < (100 * 1024 * 1024)) {
3262                 spin_lock(&block_group->lock);
3263                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3264                 spin_unlock(&block_group->lock);
3265                 return 0;
3266         }
3267
3268         if (trans->aborted)
3269                 return 0;
3270 again:
3271         inode = lookup_free_space_inode(root, block_group, path);
3272         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3273                 ret = PTR_ERR(inode);
3274                 btrfs_release_path(path);
3275                 goto out;
3276         }
3277
3278         if (IS_ERR(inode)) {
3279                 BUG_ON(retries);
3280                 retries++;
3281
3282                 if (block_group->ro)
3283                         goto out_free;
3284
3285                 ret = create_free_space_inode(root, trans, block_group, path);
3286                 if (ret)
3287                         goto out_free;
3288                 goto again;
3289         }
3290
3291         /* We've already setup this transaction, go ahead and exit */
3292         if (block_group->cache_generation == trans->transid &&
3293             i_size_read(inode)) {
3294                 dcs = BTRFS_DC_SETUP;
3295                 goto out_put;
3296         }
3297
3298         /*
3299          * We want to set the generation to 0, that way if anything goes wrong
3300          * from here on out we know not to trust this cache when we load up next
3301          * time.
3302          */
3303         BTRFS_I(inode)->generation = 0;
3304         ret = btrfs_update_inode(trans, root, inode);
3305         if (ret) {
3306                 /*
3307                  * So theoretically we could recover from this, simply set the
3308                  * super cache generation to 0 so we know to invalidate the
3309                  * cache, but then we'd have to keep track of the block groups
3310                  * that fail this way so we know we _have_ to reset this cache
3311                  * before the next commit or risk reading stale cache.  So to
3312                  * limit our exposure to horrible edge cases lets just abort the
3313                  * transaction, this only happens in really bad situations
3314                  * anyway.
3315                  */
3316                 btrfs_abort_transaction(trans, root, ret);
3317                 goto out_put;
3318         }
3319         WARN_ON(ret);
3320
3321         if (i_size_read(inode) > 0) {
3322                 ret = btrfs_check_trunc_cache_free_space(root,
3323                                         &root->fs_info->global_block_rsv);
3324                 if (ret)
3325                         goto out_put;
3326
3327                 ret = btrfs_truncate_free_space_cache(root, trans, NULL, inode);
3328                 if (ret)
3329                         goto out_put;
3330         }
3331
3332         spin_lock(&block_group->lock);
3333         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3334             !btrfs_test_opt(root, SPACE_CACHE)) {
3335                 /*
3336                  * don't bother trying to write stuff out _if_
3337                  * a) we're not cached,
3338                  * b) we're with nospace_cache mount option.
3339                  */
3340                 dcs = BTRFS_DC_WRITTEN;
3341                 spin_unlock(&block_group->lock);
3342                 goto out_put;
3343         }
3344         spin_unlock(&block_group->lock);
3345
3346         /*
3347          * Try to preallocate enough space based on how big the block group is.
3348          * Keep in mind this has to include any pinned space which could end up
3349          * taking up quite a bit since it's not folded into the other space
3350          * cache.
3351          */
3352         num_pages = div_u64(block_group->key.offset, 256 * 1024 * 1024);
3353         if (!num_pages)
3354                 num_pages = 1;
3355
3356         num_pages *= 16;
3357         num_pages *= PAGE_CACHE_SIZE;
3358
3359         ret = btrfs_check_data_free_space(inode, 0, num_pages);
3360         if (ret)
3361                 goto out_put;
3362
3363         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3364                                               num_pages, num_pages,
3365                                               &alloc_hint);
3366         if (!ret)
3367                 dcs = BTRFS_DC_SETUP;
3368         btrfs_free_reserved_data_space(inode, 0, num_pages);
3369
3370 out_put:
3371         iput(inode);
3372 out_free:
3373         btrfs_release_path(path);
3374 out:
3375         spin_lock(&block_group->lock);
3376         if (!ret && dcs == BTRFS_DC_SETUP)
3377                 block_group->cache_generation = trans->transid;
3378         block_group->disk_cache_state = dcs;
3379         spin_unlock(&block_group->lock);
3380
3381         return ret;
3382 }
3383
3384 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3385                             struct btrfs_root *root)
3386 {
3387         struct btrfs_block_group_cache *cache, *tmp;
3388         struct btrfs_transaction *cur_trans = trans->transaction;
3389         struct btrfs_path *path;
3390
3391         if (list_empty(&cur_trans->dirty_bgs) ||
3392             !btrfs_test_opt(root, SPACE_CACHE))
3393                 return 0;
3394
3395         path = btrfs_alloc_path();
3396         if (!path)
3397                 return -ENOMEM;
3398
3399         /* Could add new block groups, use _safe just in case */
3400         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3401                                  dirty_list) {
3402                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3403                         cache_save_setup(cache, trans, path);
3404         }
3405
3406         btrfs_free_path(path);
3407         return 0;
3408 }
3409
3410 /*
3411  * transaction commit does final block group cache writeback during a
3412  * critical section where nothing is allowed to change the FS.  This is
3413  * required in order for the cache to actually match the block group,
3414  * but can introduce a lot of latency into the commit.
3415  *
3416  * So, btrfs_start_dirty_block_groups is here to kick off block group
3417  * cache IO.  There's a chance we'll have to redo some of it if the
3418  * block group changes again during the commit, but it greatly reduces
3419  * the commit latency by getting rid of the easy block groups while
3420  * we're still allowing others to join the commit.
3421  */
3422 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3423                                    struct btrfs_root *root)
3424 {
3425         struct btrfs_block_group_cache *cache;
3426         struct btrfs_transaction *cur_trans = trans->transaction;
3427         int ret = 0;
3428         int should_put;
3429         struct btrfs_path *path = NULL;
3430         LIST_HEAD(dirty);
3431         struct list_head *io = &cur_trans->io_bgs;
3432         int num_started = 0;
3433         int loops = 0;
3434
3435         spin_lock(&cur_trans->dirty_bgs_lock);
3436         if (list_empty(&cur_trans->dirty_bgs)) {
3437                 spin_unlock(&cur_trans->dirty_bgs_lock);
3438                 return 0;
3439         }
3440         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3441         spin_unlock(&cur_trans->dirty_bgs_lock);
3442
3443 again:
3444         /*
3445          * make sure all the block groups on our dirty list actually
3446          * exist
3447          */
3448         btrfs_create_pending_block_groups(trans, root);
3449
3450         if (!path) {
3451                 path = btrfs_alloc_path();
3452                 if (!path)
3453                         return -ENOMEM;
3454         }
3455
3456         /*
3457          * cache_write_mutex is here only to save us from balance or automatic
3458          * removal of empty block groups deleting this block group while we are
3459          * writing out the cache
3460          */
3461         mutex_lock(&trans->transaction->cache_write_mutex);
3462         while (!list_empty(&dirty)) {
3463                 cache = list_first_entry(&dirty,
3464                                          struct btrfs_block_group_cache,
3465                                          dirty_list);
3466                 /*
3467                  * this can happen if something re-dirties a block
3468                  * group that is already under IO.  Just wait for it to
3469                  * finish and then do it all again
3470                  */
3471                 if (!list_empty(&cache->io_list)) {
3472                         list_del_init(&cache->io_list);
3473                         btrfs_wait_cache_io(root, trans, cache,
3474                                             &cache->io_ctl, path,
3475                                             cache->key.objectid);
3476                         btrfs_put_block_group(cache);
3477                 }
3478
3479
3480                 /*
3481                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3482                  * if it should update the cache_state.  Don't delete
3483                  * until after we wait.
3484                  *
3485                  * Since we're not running in the commit critical section
3486                  * we need the dirty_bgs_lock to protect from update_block_group
3487                  */
3488                 spin_lock(&cur_trans->dirty_bgs_lock);
3489                 list_del_init(&cache->dirty_list);
3490                 spin_unlock(&cur_trans->dirty_bgs_lock);
3491
3492                 should_put = 1;
3493
3494                 cache_save_setup(cache, trans, path);
3495
3496                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3497                         cache->io_ctl.inode = NULL;
3498                         ret = btrfs_write_out_cache(root, trans, cache, path);
3499                         if (ret == 0 && cache->io_ctl.inode) {
3500                                 num_started++;
3501                                 should_put = 0;
3502
3503                                 /*
3504                                  * the cache_write_mutex is protecting
3505                                  * the io_list
3506                                  */
3507                                 list_add_tail(&cache->io_list, io);
3508                         } else {
3509                                 /*
3510                                  * if we failed to write the cache, the
3511                                  * generation will be bad and life goes on
3512                                  */
3513                                 ret = 0;
3514                         }
3515                 }
3516                 if (!ret) {
3517                         ret = write_one_cache_group(trans, root, path, cache);
3518                         /*
3519                          * Our block group might still be attached to the list
3520                          * of new block groups in the transaction handle of some
3521                          * other task (struct btrfs_trans_handle->new_bgs). This
3522                          * means its block group item isn't yet in the extent
3523                          * tree. If this happens ignore the error, as we will
3524                          * try again later in the critical section of the
3525                          * transaction commit.
3526                          */
3527                         if (ret == -ENOENT) {
3528                                 ret = 0;
3529                                 spin_lock(&cur_trans->dirty_bgs_lock);
3530                                 if (list_empty(&cache->dirty_list)) {
3531                                         list_add_tail(&cache->dirty_list,
3532                                                       &cur_trans->dirty_bgs);
3533                                         btrfs_get_block_group(cache);
3534                                 }
3535                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3536                         } else if (ret) {
3537                                 btrfs_abort_transaction(trans, root, ret);
3538                         }
3539                 }
3540
3541                 /* if its not on the io list, we need to put the block group */
3542                 if (should_put)
3543                         btrfs_put_block_group(cache);
3544
3545                 if (ret)
3546                         break;
3547
3548                 /*
3549                  * Avoid blocking other tasks for too long. It might even save
3550                  * us from writing caches for block groups that are going to be
3551                  * removed.
3552                  */
3553                 mutex_unlock(&trans->transaction->cache_write_mutex);
3554                 mutex_lock(&trans->transaction->cache_write_mutex);
3555         }
3556         mutex_unlock(&trans->transaction->cache_write_mutex);
3557
3558         /*
3559          * go through delayed refs for all the stuff we've just kicked off
3560          * and then loop back (just once)
3561          */
3562         ret = btrfs_run_delayed_refs(trans, root, 0);
3563         if (!ret && loops == 0) {
3564                 loops++;
3565                 spin_lock(&cur_trans->dirty_bgs_lock);
3566                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3567                 /*
3568                  * dirty_bgs_lock protects us from concurrent block group
3569                  * deletes too (not just cache_write_mutex).
3570                  */
3571                 if (!list_empty(&dirty)) {
3572                         spin_unlock(&cur_trans->dirty_bgs_lock);
3573                         goto again;
3574                 }
3575                 spin_unlock(&cur_trans->dirty_bgs_lock);
3576         }
3577
3578         btrfs_free_path(path);
3579         return ret;
3580 }
3581
3582 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3583                                    struct btrfs_root *root)
3584 {
3585         struct btrfs_block_group_cache *cache;
3586         struct btrfs_transaction *cur_trans = trans->transaction;
3587         int ret = 0;
3588         int should_put;
3589         struct btrfs_path *path;
3590         struct list_head *io = &cur_trans->io_bgs;
3591         int num_started = 0;
3592
3593         path = btrfs_alloc_path();
3594         if (!path)
3595                 return -ENOMEM;
3596
3597         /*
3598          * We don't need the lock here since we are protected by the transaction
3599          * commit.  We want to do the cache_save_setup first and then run the
3600          * delayed refs to make sure we have the best chance at doing this all
3601          * in one shot.
3602          */
3603         while (!list_empty(&cur_trans->dirty_bgs)) {
3604                 cache = list_first_entry(&cur_trans->dirty_bgs,
3605                                          struct btrfs_block_group_cache,
3606                                          dirty_list);
3607
3608                 /*
3609                  * this can happen if cache_save_setup re-dirties a block
3610                  * group that is already under IO.  Just wait for it to
3611                  * finish and then do it all again
3612                  */
3613                 if (!list_empty(&cache->io_list)) {
3614                         list_del_init(&cache->io_list);
3615                         btrfs_wait_cache_io(root, trans, cache,
3616                                             &cache->io_ctl, path,
3617                                             cache->key.objectid);
3618                         btrfs_put_block_group(cache);
3619                 }
3620
3621                 /*
3622                  * don't remove from the dirty list until after we've waited
3623                  * on any pending IO
3624                  */
3625                 list_del_init(&cache->dirty_list);
3626                 should_put = 1;
3627
3628                 cache_save_setup(cache, trans, path);
3629
3630                 if (!ret)
3631                         ret = btrfs_run_delayed_refs(trans, root, (unsigned long) -1);
3632
3633                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3634                         cache->io_ctl.inode = NULL;
3635                         ret = btrfs_write_out_cache(root, trans, cache, path);
3636                         if (ret == 0 && cache->io_ctl.inode) {
3637                                 num_started++;
3638                                 should_put = 0;
3639                                 list_add_tail(&cache->io_list, io);
3640                         } else {
3641                                 /*
3642                                  * if we failed to write the cache, the
3643                                  * generation will be bad and life goes on
3644                                  */
3645                                 ret = 0;
3646                         }
3647                 }
3648                 if (!ret) {
3649                         ret = write_one_cache_group(trans, root, path, cache);
3650                         if (ret)
3651                                 btrfs_abort_transaction(trans, root, ret);
3652                 }
3653
3654                 /* if its not on the io list, we need to put the block group */
3655                 if (should_put)
3656                         btrfs_put_block_group(cache);
3657         }
3658
3659         while (!list_empty(io)) {
3660                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3661                                          io_list);
3662                 list_del_init(&cache->io_list);
3663                 btrfs_wait_cache_io(root, trans, cache,
3664                                     &cache->io_ctl, path, cache->key.objectid);
3665                 btrfs_put_block_group(cache);
3666         }
3667
3668         btrfs_free_path(path);
3669         return ret;
3670 }
3671
3672 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3673 {
3674         struct btrfs_block_group_cache *block_group;
3675         int readonly = 0;
3676
3677         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3678         if (!block_group || block_group->ro)
3679                 readonly = 1;
3680         if (block_group)
3681                 btrfs_put_block_group(block_group);
3682         return readonly;
3683 }
3684
3685 static const char *alloc_name(u64 flags)
3686 {
3687         switch (flags) {
3688         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
3689                 return "mixed";
3690         case BTRFS_BLOCK_GROUP_METADATA:
3691                 return "metadata";
3692         case BTRFS_BLOCK_GROUP_DATA:
3693                 return "data";
3694         case BTRFS_BLOCK_GROUP_SYSTEM:
3695                 return "system";
3696         default:
3697                 WARN_ON(1);
3698                 return "invalid-combination";
3699         };
3700 }
3701
3702 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3703                              u64 total_bytes, u64 bytes_used,
3704                              struct btrfs_space_info **space_info)
3705 {
3706         struct btrfs_space_info *found;
3707         int i;
3708         int factor;
3709         int ret;
3710
3711         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3712                      BTRFS_BLOCK_GROUP_RAID10))
3713                 factor = 2;
3714         else
3715                 factor = 1;
3716
3717         found = __find_space_info(info, flags);
3718         if (found) {
3719                 spin_lock(&found->lock);
3720                 found->total_bytes += total_bytes;
3721                 found->disk_total += total_bytes * factor;
3722                 found->bytes_used += bytes_used;
3723                 found->disk_used += bytes_used * factor;
3724                 if (total_bytes > 0)
3725                         found->full = 0;
3726                 spin_unlock(&found->lock);
3727                 *space_info = found;
3728                 return 0;
3729         }
3730         found = kzalloc(sizeof(*found), GFP_NOFS);
3731         if (!found)
3732                 return -ENOMEM;
3733
3734         ret = percpu_counter_init(&found->total_bytes_pinned, 0, GFP_KERNEL);
3735         if (ret) {
3736                 kfree(found);
3737                 return ret;
3738         }
3739
3740         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3741                 INIT_LIST_HEAD(&found->block_groups[i]);
3742         init_rwsem(&found->groups_sem);
3743         spin_lock_init(&found->lock);
3744         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3745         found->total_bytes = total_bytes;
3746         found->disk_total = total_bytes * factor;
3747         found->bytes_used = bytes_used;
3748         found->disk_used = bytes_used * factor;
3749         found->bytes_pinned = 0;
3750         found->bytes_reserved = 0;
3751         found->bytes_readonly = 0;
3752         found->bytes_may_use = 0;
3753         found->full = 0;
3754         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3755         found->chunk_alloc = 0;
3756         found->flush = 0;
3757         init_waitqueue_head(&found->wait);
3758         INIT_LIST_HEAD(&found->ro_bgs);
3759
3760         ret = kobject_init_and_add(&found->kobj, &space_info_ktype,
3761                                     info->space_info_kobj, "%s",
3762                                     alloc_name(found->flags));
3763         if (ret) {
3764                 kfree(found);
3765                 return ret;
3766         }
3767
3768         *space_info = found;
3769         list_add_rcu(&found->list, &info->space_info);
3770         if (flags & BTRFS_BLOCK_GROUP_DATA)
3771                 info->data_sinfo = found;
3772
3773         return ret;
3774 }
3775
3776 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3777 {
3778         u64 extra_flags = chunk_to_extended(flags) &
3779                                 BTRFS_EXTENDED_PROFILE_MASK;
3780
3781         write_seqlock(&fs_info->profiles_lock);
3782         if (flags & BTRFS_BLOCK_GROUP_DATA)
3783                 fs_info->avail_data_alloc_bits |= extra_flags;
3784         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3785                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3786         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3787                 fs_info->avail_system_alloc_bits |= extra_flags;
3788         write_sequnlock(&fs_info->profiles_lock);
3789 }
3790
3791 /*
3792  * returns target flags in extended format or 0 if restripe for this
3793  * chunk_type is not in progress
3794  *
3795  * should be called with either volume_mutex or balance_lock held
3796  */
3797 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3798 {
3799         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3800         u64 target = 0;
3801
3802         if (!bctl)
3803                 return 0;
3804
3805         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3806             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3807                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3808         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3809                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3810                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3811         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3812                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3813                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3814         }
3815
3816         return target;
3817 }
3818
3819 /*
3820  * @flags: available profiles in extended format (see ctree.h)
3821  *
3822  * Returns reduced profile in chunk format.  If profile changing is in
3823  * progress (either running or paused) picks the target profile (if it's
3824  * already available), otherwise falls back to plain reducing.
3825  */
3826 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3827 {
3828         u64 num_devices = root->fs_info->fs_devices->rw_devices;
3829         u64 target;
3830         u64 raid_type;
3831         u64 allowed = 0;
3832
3833         /*
3834          * see if restripe for this chunk_type is in progress, if so
3835          * try to reduce to the target profile
3836          */
3837         spin_lock(&root->fs_info->balance_lock);
3838         target = get_restripe_target(root->fs_info, flags);
3839         if (target) {
3840                 /* pick target profile only if it's already available */
3841                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3842                         spin_unlock(&root->fs_info->balance_lock);
3843                         return extended_to_chunk(target);
3844                 }
3845         }
3846         spin_unlock(&root->fs_info->balance_lock);
3847
3848         /* First, mask out the RAID levels which aren't possible */
3849         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
3850                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
3851                         allowed |= btrfs_raid_group[raid_type];
3852         }
3853         allowed &= flags;
3854
3855         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
3856                 allowed = BTRFS_BLOCK_GROUP_RAID6;
3857         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
3858                 allowed = BTRFS_BLOCK_GROUP_RAID5;
3859         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
3860                 allowed = BTRFS_BLOCK_GROUP_RAID10;
3861         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
3862                 allowed = BTRFS_BLOCK_GROUP_RAID1;
3863         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
3864                 allowed = BTRFS_BLOCK_GROUP_RAID0;
3865
3866         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
3867
3868         return extended_to_chunk(flags | allowed);
3869 }
3870
3871 static u64 get_alloc_profile(struct btrfs_root *root, u64 orig_flags)
3872 {
3873         unsigned seq;
3874         u64 flags;
3875
3876         do {
3877                 flags = orig_flags;
3878                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3879
3880                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3881                         flags |= root->fs_info->avail_data_alloc_bits;
3882                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3883                         flags |= root->fs_info->avail_system_alloc_bits;
3884                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3885                         flags |= root->fs_info->avail_metadata_alloc_bits;
3886         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3887
3888         return btrfs_reduce_alloc_profile(root, flags);
3889 }
3890
3891 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3892 {
3893         u64 flags;
3894         u64 ret;
3895
3896         if (data)
3897                 flags = BTRFS_BLOCK_GROUP_DATA;
3898         else if (root == root->fs_info->chunk_root)
3899                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3900         else
3901                 flags = BTRFS_BLOCK_GROUP_METADATA;
3902
3903         ret = get_alloc_profile(root, flags);
3904         return ret;
3905 }
3906
3907 int btrfs_alloc_data_chunk_ondemand(struct inode *inode, u64 bytes)
3908 {
3909         struct btrfs_space_info *data_sinfo;
3910         struct btrfs_root *root = BTRFS_I(inode)->root;
3911         struct btrfs_fs_info *fs_info = root->fs_info;
3912         u64 used;
3913         int ret = 0;
3914         int need_commit = 2;
3915         int have_pinned_space;
3916
3917         /* make sure bytes are sectorsize aligned */
3918         bytes = ALIGN(bytes, root->sectorsize);
3919
3920         if (btrfs_is_free_space_inode(inode)) {
3921                 need_commit = 0;
3922                 ASSERT(current->journal_info);
3923         }
3924
3925         data_sinfo = fs_info->data_sinfo;
3926         if (!data_sinfo)
3927                 goto alloc;
3928
3929 again:
3930         /* make sure we have enough space to handle the data first */
3931         spin_lock(&data_sinfo->lock);
3932         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3933                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3934                 data_sinfo->bytes_may_use;
3935
3936         if (used + bytes > data_sinfo->total_bytes) {
3937                 struct btrfs_trans_handle *trans;
3938
3939                 /*
3940                  * if we don't have enough free bytes in this space then we need
3941                  * to alloc a new chunk.
3942                  */
3943                 if (!data_sinfo->full) {
3944                         u64 alloc_target;
3945
3946                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3947                         spin_unlock(&data_sinfo->lock);
3948 alloc:
3949                         alloc_target = btrfs_get_alloc_profile(root, 1);
3950                         /*
3951                          * It is ugly that we don't call nolock join
3952                          * transaction for the free space inode case here.
3953                          * But it is safe because we only do the data space
3954                          * reservation for the free space cache in the
3955                          * transaction context, the common join transaction
3956                          * just increase the counter of the current transaction
3957                          * handler, doesn't try to acquire the trans_lock of
3958                          * the fs.
3959                          */
3960                         trans = btrfs_join_transaction(root);
3961                         if (IS_ERR(trans))
3962                                 return PTR_ERR(trans);
3963
3964                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3965                                              alloc_target,
3966                                              CHUNK_ALLOC_NO_FORCE);
3967                         btrfs_end_transaction(trans, root);
3968                         if (ret < 0) {
3969                                 if (ret != -ENOSPC)
3970                                         return ret;
3971                                 else {
3972                                         have_pinned_space = 1;
3973                                         goto commit_trans;
3974                                 }
3975                         }
3976
3977                         if (!data_sinfo)
3978                                 data_sinfo = fs_info->data_sinfo;
3979
3980                         goto again;
3981                 }
3982
3983                 /*
3984                  * If we don't have enough pinned space to deal with this
3985                  * allocation, and no removed chunk in current transaction,
3986                  * don't bother committing the transaction.
3987                  */
3988                 have_pinned_space = percpu_counter_compare(
3989                         &data_sinfo->total_bytes_pinned,
3990                         used + bytes - data_sinfo->total_bytes);
3991                 spin_unlock(&data_sinfo->lock);
3992
3993                 /* commit the current transaction and try again */
3994 commit_trans:
3995                 if (need_commit &&
3996                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3997                         need_commit--;
3998
3999                         if (need_commit > 0)
4000                                 btrfs_wait_ordered_roots(fs_info, -1);
4001
4002                         trans = btrfs_join_transaction(root);
4003                         if (IS_ERR(trans))
4004                                 return PTR_ERR(trans);
4005                         if (have_pinned_space >= 0 ||
4006                             trans->transaction->have_free_bgs ||
4007                             need_commit > 0) {
4008                                 ret = btrfs_commit_transaction(trans, root);
4009                                 if (ret)
4010                                         return ret;
4011                                 /*
4012                                  * make sure that all running delayed iput are
4013                                  * done
4014                                  */
4015                                 down_write(&root->fs_info->delayed_iput_sem);
4016                                 up_write(&root->fs_info->delayed_iput_sem);
4017                                 goto again;
4018                         } else {
4019                                 btrfs_end_transaction(trans, root);
4020                         }
4021                 }
4022
4023                 trace_btrfs_space_reservation(root->fs_info,
4024                                               "space_info:enospc",
4025                                               data_sinfo->flags, bytes, 1);
4026                 return -ENOSPC;
4027         }
4028         data_sinfo->bytes_may_use += bytes;
4029         trace_btrfs_space_reservation(root->fs_info, "space_info",
4030                                       data_sinfo->flags, bytes, 1);
4031         spin_unlock(&data_sinfo->lock);
4032
4033         return ret;
4034 }
4035
4036 /*
4037  * New check_data_free_space() with ability for precious data reservation
4038  * Will replace old btrfs_check_data_free_space(), but for patch split,
4039  * add a new function first and then replace it.
4040  */
4041 int btrfs_check_data_free_space(struct inode *inode, u64 start, u64 len)
4042 {
4043         struct btrfs_root *root = BTRFS_I(inode)->root;
4044         int ret;
4045
4046         /* align the range */
4047         len = round_up(start + len, root->sectorsize) -
4048               round_down(start, root->sectorsize);
4049         start = round_down(start, root->sectorsize);
4050
4051         ret = btrfs_alloc_data_chunk_ondemand(inode, len);
4052         if (ret < 0)
4053                 return ret;
4054
4055         /*
4056          * Use new btrfs_qgroup_reserve_data to reserve precious data space
4057          *
4058          * TODO: Find a good method to avoid reserve data space for NOCOW
4059          * range, but don't impact performance on quota disable case.
4060          */
4061         ret = btrfs_qgroup_reserve_data(inode, start, len);
4062         return ret;
4063 }
4064
4065 /*
4066  * Called if we need to clear a data reservation for this inode
4067  * Normally in a error case.
4068  *
4069  * This one will *NOT* use accurate qgroup reserved space API, just for case
4070  * which we can't sleep and is sure it won't affect qgroup reserved space.
4071  * Like clear_bit_hook().
4072  */
4073 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4074                                             u64 len)
4075 {
4076         struct btrfs_root *root = BTRFS_I(inode)->root;
4077         struct btrfs_space_info *data_sinfo;
4078
4079         /* Make sure the range is aligned to sectorsize */
4080         len = round_up(start + len, root->sectorsize) -
4081               round_down(start, root->sectorsize);
4082         start = round_down(start, root->sectorsize);
4083
4084         data_sinfo = root->fs_info->data_sinfo;
4085         spin_lock(&data_sinfo->lock);
4086         if (WARN_ON(data_sinfo->bytes_may_use < len))
4087                 data_sinfo->bytes_may_use = 0;
4088         else
4089                 data_sinfo->bytes_may_use -= len;
4090         trace_btrfs_space_reservation(root->fs_info, "space_info",
4091                                       data_sinfo->flags, len, 0);
4092         spin_unlock(&data_sinfo->lock);
4093 }
4094
4095 /*
4096  * Called if we need to clear a data reservation for this inode
4097  * Normally in a error case.
4098  *
4099  * This one will handle the per-indoe data rsv map for accurate reserved
4100  * space framework.
4101  */
4102 void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
4103 {
4104         btrfs_free_reserved_data_space_noquota(inode, start, len);
4105         btrfs_qgroup_free_data(inode, start, len);
4106 }
4107
4108 static void force_metadata_allocation(struct btrfs_fs_info *info)
4109 {
4110         struct list_head *head = &info->space_info;
4111         struct btrfs_space_info *found;
4112
4113         rcu_read_lock();
4114         list_for_each_entry_rcu(found, head, list) {
4115                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4116                         found->force_alloc = CHUNK_ALLOC_FORCE;
4117         }
4118         rcu_read_unlock();
4119 }
4120
4121 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4122 {
4123         return (global->size << 1);
4124 }
4125
4126 static int should_alloc_chunk(struct btrfs_root *root,
4127                               struct btrfs_space_info *sinfo, int force)
4128 {
4129         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4130         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
4131         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
4132         u64 thresh;
4133
4134         if (force == CHUNK_ALLOC_FORCE)
4135                 return 1;
4136
4137         /*
4138          * We need to take into account the global rsv because for all intents
4139          * and purposes it's used space.  Don't worry about locking the
4140          * global_rsv, it doesn't change except when the transaction commits.
4141          */
4142         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4143                 num_allocated += calc_global_rsv_need_space(global_rsv);
4144
4145         /*
4146          * in limited mode, we want to have some free space up to
4147          * about 1% of the FS size.
4148          */
4149         if (force == CHUNK_ALLOC_LIMITED) {
4150                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
4151                 thresh = max_t(u64, 64 * 1024 * 1024,
4152                                div_factor_fine(thresh, 1));
4153
4154                 if (num_bytes - num_allocated < thresh)
4155                         return 1;
4156         }
4157
4158         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
4159                 return 0;
4160         return 1;
4161 }
4162
4163 static u64 get_profile_num_devs(struct btrfs_root *root, u64 type)
4164 {
4165         u64 num_dev;
4166
4167         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4168                     BTRFS_BLOCK_GROUP_RAID0 |
4169                     BTRFS_BLOCK_GROUP_RAID5 |
4170                     BTRFS_BLOCK_GROUP_RAID6))
4171                 num_dev = root->fs_info->fs_devices->rw_devices;
4172         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4173                 num_dev = 2;
4174         else
4175                 num_dev = 1;    /* DUP or single */
4176
4177         return num_dev;
4178 }
4179
4180 /*
4181  * If @is_allocation is true, reserve space in the system space info necessary
4182  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4183  * removing a chunk.
4184  */
4185 void check_system_chunk(struct btrfs_trans_handle *trans,
4186                         struct btrfs_root *root,
4187                         u64 type)
4188 {
4189         struct btrfs_space_info *info;
4190         u64 left;
4191         u64 thresh;
4192         int ret = 0;
4193         u64 num_devs;
4194
4195         /*
4196          * Needed because we can end up allocating a system chunk and for an
4197          * atomic and race free space reservation in the chunk block reserve.
4198          */
4199         ASSERT(mutex_is_locked(&root->fs_info->chunk_mutex));
4200
4201         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4202         spin_lock(&info->lock);
4203         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
4204                 info->bytes_reserved - info->bytes_readonly -
4205                 info->bytes_may_use;
4206         spin_unlock(&info->lock);
4207
4208         num_devs = get_profile_num_devs(root, type);
4209
4210         /* num_devs device items to update and 1 chunk item to add or remove */
4211         thresh = btrfs_calc_trunc_metadata_size(root, num_devs) +
4212                 btrfs_calc_trans_metadata_size(root, 1);
4213
4214         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
4215                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
4216                         left, thresh, type);
4217                 dump_space_info(info, 0, 0);
4218         }
4219
4220         if (left < thresh) {
4221                 u64 flags;
4222
4223                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
4224                 /*
4225                  * Ignore failure to create system chunk. We might end up not
4226                  * needing it, as we might not need to COW all nodes/leafs from
4227                  * the paths we visit in the chunk tree (they were already COWed
4228                  * or created in the current transaction for example).
4229                  */
4230                 ret = btrfs_alloc_chunk(trans, root, flags);
4231         }
4232
4233         if (!ret) {
4234                 ret = btrfs_block_rsv_add(root->fs_info->chunk_root,
4235                                           &root->fs_info->chunk_block_rsv,
4236                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4237                 if (!ret)
4238                         trans->chunk_bytes_reserved += thresh;
4239         }
4240 }
4241
4242 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4243                           struct btrfs_root *extent_root, u64 flags, int force)
4244 {
4245         struct btrfs_space_info *space_info;
4246         struct btrfs_fs_info *fs_info = extent_root->fs_info;
4247         int wait_for_alloc = 0;
4248         int ret = 0;
4249
4250         /* Don't re-enter if we're already allocating a chunk */
4251         if (trans->allocating_chunk)
4252                 return -ENOSPC;
4253
4254         space_info = __find_space_info(extent_root->fs_info, flags);
4255         if (!space_info) {
4256                 ret = update_space_info(extent_root->fs_info, flags,
4257                                         0, 0, &space_info);
4258                 BUG_ON(ret); /* -ENOMEM */
4259         }
4260         BUG_ON(!space_info); /* Logic error */
4261
4262 again:
4263         spin_lock(&space_info->lock);
4264         if (force < space_info->force_alloc)
4265                 force = space_info->force_alloc;
4266         if (space_info->full) {
4267                 if (should_alloc_chunk(extent_root, space_info, force))
4268                         ret = -ENOSPC;
4269                 else
4270                         ret = 0;
4271                 spin_unlock(&space_info->lock);
4272                 return ret;
4273         }
4274
4275         if (!should_alloc_chunk(extent_root, space_info, force)) {
4276                 spin_unlock(&space_info->lock);
4277                 return 0;
4278         } else if (space_info->chunk_alloc) {
4279                 wait_for_alloc = 1;
4280         } else {
4281                 space_info->chunk_alloc = 1;
4282         }
4283
4284         spin_unlock(&space_info->lock);
4285
4286         mutex_lock(&fs_info->chunk_mutex);
4287
4288         /*
4289          * The chunk_mutex is held throughout the entirety of a chunk
4290          * allocation, so once we've acquired the chunk_mutex we know that the
4291          * other guy is done and we need to recheck and see if we should
4292          * allocate.
4293          */
4294         if (wait_for_alloc) {
4295                 mutex_unlock(&fs_info->chunk_mutex);
4296                 wait_for_alloc = 0;
4297                 goto again;
4298         }
4299
4300         trans->allocating_chunk = true;
4301
4302         /*
4303          * If we have mixed data/metadata chunks we want to make sure we keep
4304          * allocating mixed chunks instead of individual chunks.
4305          */
4306         if (btrfs_mixed_space_info(space_info))
4307                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4308
4309         /*
4310          * if we're doing a data chunk, go ahead and make sure that
4311          * we keep a reasonable number of metadata chunks allocated in the
4312          * FS as well.
4313          */
4314         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4315                 fs_info->data_chunk_allocations++;
4316                 if (!(fs_info->data_chunk_allocations %
4317                       fs_info->metadata_ratio))
4318                         force_metadata_allocation(fs_info);
4319         }
4320
4321         /*
4322          * Check if we have enough space in SYSTEM chunk because we may need
4323          * to update devices.
4324          */
4325         check_system_chunk(trans, extent_root, flags);
4326
4327         ret = btrfs_alloc_chunk(trans, extent_root, flags);
4328         trans->allocating_chunk = false;
4329
4330         spin_lock(&space_info->lock);
4331         if (ret < 0 && ret != -ENOSPC)
4332                 goto out;
4333         if (ret)
4334                 space_info->full = 1;
4335         else
4336                 ret = 1;
4337
4338         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4339 out:
4340         space_info->chunk_alloc = 0;
4341         spin_unlock(&space_info->lock);
4342         mutex_unlock(&fs_info->chunk_mutex);
4343         /*
4344          * When we allocate a new chunk we reserve space in the chunk block
4345          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4346          * add new nodes/leafs to it if we end up needing to do it when
4347          * inserting the chunk item and updating device items as part of the
4348          * second phase of chunk allocation, performed by
4349          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4350          * large number of new block groups to create in our transaction
4351          * handle's new_bgs list to avoid exhausting the chunk block reserve
4352          * in extreme cases - like having a single transaction create many new
4353          * block groups when starting to write out the free space caches of all
4354          * the block groups that were made dirty during the lifetime of the
4355          * transaction.
4356          */
4357         if (trans->can_flush_pending_bgs &&
4358             trans->chunk_bytes_reserved >= (2 * 1024 * 1024ull)) {
4359                 btrfs_create_pending_block_groups(trans, trans->root);
4360                 btrfs_trans_release_chunk_metadata(trans);
4361         }
4362         return ret;
4363 }
4364
4365 static int can_overcommit(struct btrfs_root *root,
4366                           struct btrfs_space_info *space_info, u64 bytes,
4367                           enum btrfs_reserve_flush_enum flush)
4368 {
4369         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4370         u64 profile = btrfs_get_alloc_profile(root, 0);
4371         u64 space_size;
4372         u64 avail;
4373         u64 used;
4374
4375         used = space_info->bytes_used + space_info->bytes_reserved +
4376                 space_info->bytes_pinned + space_info->bytes_readonly;
4377
4378         /*
4379          * We only want to allow over committing if we have lots of actual space
4380          * free, but if we don't have enough space to handle the global reserve
4381          * space then we could end up having a real enospc problem when trying
4382          * to allocate a chunk or some other such important allocation.
4383          */
4384         spin_lock(&global_rsv->lock);
4385         space_size = calc_global_rsv_need_space(global_rsv);
4386         spin_unlock(&global_rsv->lock);
4387         if (used + space_size >= space_info->total_bytes)
4388                 return 0;
4389
4390         used += space_info->bytes_may_use;
4391
4392         spin_lock(&root->fs_info->free_chunk_lock);
4393         avail = root->fs_info->free_chunk_space;
4394         spin_unlock(&root->fs_info->free_chunk_lock);
4395
4396         /*
4397          * If we have dup, raid1 or raid10 then only half of the free
4398          * space is actually useable.  For raid56, the space info used
4399          * doesn't include the parity drive, so we don't have to
4400          * change the math
4401          */
4402         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4403                        BTRFS_BLOCK_GROUP_RAID1 |
4404                        BTRFS_BLOCK_GROUP_RAID10))
4405                 avail >>= 1;
4406
4407         /*
4408          * If we aren't flushing all things, let us overcommit up to
4409          * 1/2th of the space. If we can flush, don't let us overcommit
4410          * too much, let it overcommit up to 1/8 of the space.
4411          */
4412         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4413                 avail >>= 3;
4414         else
4415                 avail >>= 1;
4416
4417         if (used + bytes < space_info->total_bytes + avail)
4418                 return 1;
4419         return 0;
4420 }
4421
4422 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4423                                          unsigned long nr_pages, int nr_items)
4424 {
4425         struct super_block *sb = root->fs_info->sb;
4426
4427         if (down_read_trylock(&sb->s_umount)) {
4428                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4429                 up_read(&sb->s_umount);
4430         } else {
4431                 /*
4432                  * We needn't worry the filesystem going from r/w to r/o though
4433                  * we don't acquire ->s_umount mutex, because the filesystem
4434                  * should guarantee the delalloc inodes list be empty after
4435                  * the filesystem is readonly(all dirty pages are written to
4436                  * the disk).
4437                  */
4438                 btrfs_start_delalloc_roots(root->fs_info, 0, nr_items);
4439                 if (!current->journal_info)
4440                         btrfs_wait_ordered_roots(root->fs_info, nr_items);
4441         }
4442 }
4443
4444 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4445 {
4446         u64 bytes;
4447         int nr;
4448
4449         bytes = btrfs_calc_trans_metadata_size(root, 1);
4450         nr = (int)div64_u64(to_reclaim, bytes);
4451         if (!nr)
4452                 nr = 1;
4453         return nr;
4454 }
4455
4456 #define EXTENT_SIZE_PER_ITEM    (256 * 1024)
4457
4458 /*
4459  * shrink metadata reservation for delalloc
4460  */
4461 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4462                             bool wait_ordered)
4463 {
4464         struct btrfs_block_rsv *block_rsv;
4465         struct btrfs_space_info *space_info;
4466         struct btrfs_trans_handle *trans;
4467         u64 delalloc_bytes;
4468         u64 max_reclaim;
4469         long time_left;
4470         unsigned long nr_pages;
4471         int loops;
4472         int items;
4473         enum btrfs_reserve_flush_enum flush;
4474
4475         /* Calc the number of the pages we need flush for space reservation */
4476         items = calc_reclaim_items_nr(root, to_reclaim);
4477         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4478
4479         trans = (struct btrfs_trans_handle *)current->journal_info;
4480         block_rsv = &root->fs_info->delalloc_block_rsv;
4481         space_info = block_rsv->space_info;
4482
4483         delalloc_bytes = percpu_counter_sum_positive(
4484                                                 &root->fs_info->delalloc_bytes);
4485         if (delalloc_bytes == 0) {
4486                 if (trans)
4487                         return;
4488                 if (wait_ordered)
4489                         btrfs_wait_ordered_roots(root->fs_info, items);
4490                 return;
4491         }
4492
4493         loops = 0;
4494         while (delalloc_bytes && loops < 3) {
4495                 max_reclaim = min(delalloc_bytes, to_reclaim);
4496                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4497                 btrfs_writeback_inodes_sb_nr(root, nr_pages, items);
4498                 /*
4499                  * We need to wait for the async pages to actually start before
4500                  * we do anything.
4501                  */
4502                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4503                 if (!max_reclaim)
4504                         goto skip_async;
4505
4506                 if (max_reclaim <= nr_pages)
4507                         max_reclaim = 0;
4508                 else
4509                         max_reclaim -= nr_pages;
4510
4511                 wait_event(root->fs_info->async_submit_wait,
4512                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4513                            (int)max_reclaim);
4514 skip_async:
4515                 if (!trans)
4516                         flush = BTRFS_RESERVE_FLUSH_ALL;
4517                 else
4518                         flush = BTRFS_RESERVE_NO_FLUSH;
4519                 spin_lock(&space_info->lock);
4520                 if (can_overcommit(root, space_info, orig, flush)) {
4521                         spin_unlock(&space_info->lock);
4522                         break;
4523                 }
4524                 spin_unlock(&space_info->lock);
4525
4526                 loops++;
4527                 if (wait_ordered && !trans) {
4528                         btrfs_wait_ordered_roots(root->fs_info, items);
4529                 } else {
4530                         time_left = schedule_timeout_killable(1);
4531                         if (time_left)
4532                                 break;
4533                 }
4534                 delalloc_bytes = percpu_counter_sum_positive(
4535                                                 &root->fs_info->delalloc_bytes);
4536         }
4537 }
4538
4539 /**
4540  * maybe_commit_transaction - possibly commit the transaction if its ok to
4541  * @root - the root we're allocating for
4542  * @bytes - the number of bytes we want to reserve
4543  * @force - force the commit
4544  *
4545  * This will check to make sure that committing the transaction will actually
4546  * get us somewhere and then commit the transaction if it does.  Otherwise it
4547  * will return -ENOSPC.
4548  */
4549 static int may_commit_transaction(struct btrfs_root *root,
4550                                   struct btrfs_space_info *space_info,
4551                                   u64 bytes, int force)
4552 {
4553         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4554         struct btrfs_trans_handle *trans;
4555
4556         trans = (struct btrfs_trans_handle *)current->journal_info;
4557         if (trans)
4558                 return -EAGAIN;
4559
4560         if (force)
4561                 goto commit;
4562
4563         /* See if there is enough pinned space to make this reservation */
4564         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4565                                    bytes) >= 0)
4566                 goto commit;
4567
4568         /*
4569          * See if there is some space in the delayed insertion reservation for
4570          * this reservation.
4571          */
4572         if (space_info != delayed_rsv->space_info)
4573                 return -ENOSPC;
4574
4575         spin_lock(&delayed_rsv->lock);
4576         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4577                                    bytes - delayed_rsv->size) >= 0) {
4578                 spin_unlock(&delayed_rsv->lock);
4579                 return -ENOSPC;
4580         }
4581         spin_unlock(&delayed_rsv->lock);
4582
4583 commit:
4584         trans = btrfs_join_transaction(root);
4585         if (IS_ERR(trans))
4586                 return -ENOSPC;
4587
4588         return btrfs_commit_transaction(trans, root);
4589 }
4590
4591 enum flush_state {
4592         FLUSH_DELAYED_ITEMS_NR  =       1,
4593         FLUSH_DELAYED_ITEMS     =       2,
4594         FLUSH_DELALLOC          =       3,
4595         FLUSH_DELALLOC_WAIT     =       4,
4596         ALLOC_CHUNK             =       5,
4597         COMMIT_TRANS            =       6,
4598 };
4599
4600 static int flush_space(struct btrfs_root *root,
4601                        struct btrfs_space_info *space_info, u64 num_bytes,
4602                        u64 orig_bytes, int state)
4603 {
4604         struct btrfs_trans_handle *trans;
4605         int nr;
4606         int ret = 0;
4607
4608         switch (state) {
4609         case FLUSH_DELAYED_ITEMS_NR:
4610         case FLUSH_DELAYED_ITEMS:
4611                 if (state == FLUSH_DELAYED_ITEMS_NR)
4612                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4613                 else
4614                         nr = -1;
4615
4616                 trans = btrfs_join_transaction(root);
4617                 if (IS_ERR(trans)) {
4618                         ret = PTR_ERR(trans);
4619                         break;
4620                 }
4621                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4622                 btrfs_end_transaction(trans, root);
4623                 break;
4624         case FLUSH_DELALLOC:
4625         case FLUSH_DELALLOC_WAIT:
4626                 shrink_delalloc(root, num_bytes * 2, orig_bytes,
4627                                 state == FLUSH_DELALLOC_WAIT);
4628                 break;
4629         case ALLOC_CHUNK:
4630                 trans = btrfs_join_transaction(root);
4631                 if (IS_ERR(trans)) {
4632                         ret = PTR_ERR(trans);
4633                         break;
4634                 }
4635                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4636                                      btrfs_get_alloc_profile(root, 0),
4637                                      CHUNK_ALLOC_NO_FORCE);
4638                 btrfs_end_transaction(trans, root);
4639                 if (ret == -ENOSPC)
4640                         ret = 0;
4641                 break;
4642         case COMMIT_TRANS:
4643                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4644                 break;
4645         default:
4646                 ret = -ENOSPC;
4647                 break;
4648         }
4649
4650         return ret;
4651 }
4652
4653 static inline u64
4654 btrfs_calc_reclaim_metadata_size(struct btrfs_root *root,
4655                                  struct btrfs_space_info *space_info)
4656 {
4657         u64 used;
4658         u64 expected;
4659         u64 to_reclaim;
4660
4661         to_reclaim = min_t(u64, num_online_cpus() * 1024 * 1024,
4662                                 16 * 1024 * 1024);
4663         spin_lock(&space_info->lock);
4664         if (can_overcommit(root, space_info, to_reclaim,
4665                            BTRFS_RESERVE_FLUSH_ALL)) {
4666                 to_reclaim = 0;
4667                 goto out;
4668         }
4669
4670         used = space_info->bytes_used + space_info->bytes_reserved +
4671                space_info->bytes_pinned + space_info->bytes_readonly +
4672                space_info->bytes_may_use;
4673         if (can_overcommit(root, space_info, 1024 * 1024,
4674                            BTRFS_RESERVE_FLUSH_ALL))
4675                 expected = div_factor_fine(space_info->total_bytes, 95);
4676         else
4677                 expected = div_factor_fine(space_info->total_bytes, 90);
4678
4679         if (used > expected)
4680                 to_reclaim = used - expected;
4681         else
4682                 to_reclaim = 0;
4683         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
4684                                      space_info->bytes_reserved);
4685 out:
4686         spin_unlock(&space_info->lock);
4687
4688         return to_reclaim;
4689 }
4690
4691 static inline int need_do_async_reclaim(struct btrfs_space_info *space_info,
4692                                         struct btrfs_fs_info *fs_info, u64 used)
4693 {
4694         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
4695
4696         /* If we're just plain full then async reclaim just slows us down. */
4697         if (space_info->bytes_used >= thresh)
4698                 return 0;
4699
4700         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
4701                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
4702 }
4703
4704 static int btrfs_need_do_async_reclaim(struct btrfs_space_info *space_info,
4705                                        struct btrfs_fs_info *fs_info,
4706                                        int flush_state)
4707 {
4708         u64 used;
4709
4710         spin_lock(&space_info->lock);
4711         /*
4712          * We run out of space and have not got any free space via flush_space,
4713          * so don't bother doing async reclaim.
4714          */
4715         if (flush_state > COMMIT_TRANS && space_info->full) {
4716                 spin_unlock(&space_info->lock);
4717                 return 0;
4718         }
4719
4720         used = space_info->bytes_used + space_info->bytes_reserved +
4721                space_info->bytes_pinned + space_info->bytes_readonly +
4722                space_info->bytes_may_use;
4723         if (need_do_async_reclaim(space_info, fs_info, used)) {
4724                 spin_unlock(&space_info->lock);
4725                 return 1;
4726         }
4727         spin_unlock(&space_info->lock);
4728
4729         return 0;
4730 }
4731
4732 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
4733 {
4734         struct btrfs_fs_info *fs_info;
4735         struct btrfs_space_info *space_info;
4736         u64 to_reclaim;
4737         int flush_state;
4738
4739         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
4740         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4741
4742         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info->fs_root,
4743                                                       space_info);
4744         if (!to_reclaim)
4745                 return;
4746
4747         flush_state = FLUSH_DELAYED_ITEMS_NR;
4748         do {
4749                 flush_space(fs_info->fs_root, space_info, to_reclaim,
4750                             to_reclaim, flush_state);
4751                 flush_state++;
4752                 if (!btrfs_need_do_async_reclaim(space_info, fs_info,
4753                                                  flush_state))
4754                         return;
4755         } while (flush_state < COMMIT_TRANS);
4756 }
4757
4758 void btrfs_init_async_reclaim_work(struct work_struct *work)
4759 {
4760         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
4761 }
4762
4763 /**
4764  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4765  * @root - the root we're allocating for
4766  * @block_rsv - the block_rsv we're allocating for
4767  * @orig_bytes - the number of bytes we want
4768  * @flush - whether or not we can flush to make our reservation
4769  *
4770  * This will reserve orgi_bytes number of bytes from the space info associated
4771  * with the block_rsv.  If there is not enough space it will make an attempt to
4772  * flush out space to make room.  It will do this by flushing delalloc if
4773  * possible or committing the transaction.  If flush is 0 then no attempts to
4774  * regain reservations will be made and this will fail if there is not enough
4775  * space already.
4776  */
4777 static int reserve_metadata_bytes(struct btrfs_root *root,
4778                                   struct btrfs_block_rsv *block_rsv,
4779                                   u64 orig_bytes,
4780                                   enum btrfs_reserve_flush_enum flush)
4781 {
4782         struct btrfs_space_info *space_info = block_rsv->space_info;
4783         u64 used;
4784         u64 num_bytes = orig_bytes;
4785         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4786         int ret = 0;
4787         bool flushing = false;
4788
4789 again:
4790         ret = 0;
4791         spin_lock(&space_info->lock);
4792         /*
4793          * We only want to wait if somebody other than us is flushing and we
4794          * are actually allowed to flush all things.
4795          */
4796         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4797                space_info->flush) {
4798                 spin_unlock(&space_info->lock);
4799                 /*
4800                  * If we have a trans handle we can't wait because the flusher
4801                  * may have to commit the transaction, which would mean we would
4802                  * deadlock since we are waiting for the flusher to finish, but
4803                  * hold the current transaction open.
4804                  */
4805                 if (current->journal_info)
4806                         return -EAGAIN;
4807                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4808                 /* Must have been killed, return */
4809                 if (ret)
4810                         return -EINTR;
4811
4812                 spin_lock(&space_info->lock);
4813         }
4814
4815         ret = -ENOSPC;
4816         used = space_info->bytes_used + space_info->bytes_reserved +
4817                 space_info->bytes_pinned + space_info->bytes_readonly +
4818                 space_info->bytes_may_use;
4819
4820         /*
4821          * The idea here is that we've not already over-reserved the block group
4822          * then we can go ahead and save our reservation first and then start
4823          * flushing if we need to.  Otherwise if we've already overcommitted
4824          * lets start flushing stuff first and then come back and try to make
4825          * our reservation.
4826          */
4827         if (used <= space_info->total_bytes) {
4828                 if (used + orig_bytes <= space_info->total_bytes) {
4829                         space_info->bytes_may_use += orig_bytes;
4830                         trace_btrfs_space_reservation(root->fs_info,
4831                                 "space_info", space_info->flags, orig_bytes, 1);
4832                         ret = 0;
4833                 } else {
4834                         /*
4835                          * Ok set num_bytes to orig_bytes since we aren't
4836                          * overocmmitted, this way we only try and reclaim what
4837                          * we need.
4838                          */
4839                         num_bytes = orig_bytes;
4840                 }
4841         } else {
4842                 /*
4843                  * Ok we're over committed, set num_bytes to the overcommitted
4844                  * amount plus the amount of bytes that we need for this
4845                  * reservation.
4846                  */
4847                 num_bytes = used - space_info->total_bytes +
4848                         (orig_bytes * 2);
4849         }
4850
4851         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4852                 space_info->bytes_may_use += orig_bytes;
4853                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4854                                               space_info->flags, orig_bytes,
4855                                               1);
4856                 ret = 0;
4857         }
4858
4859         /*
4860          * Couldn't make our reservation, save our place so while we're trying
4861          * to reclaim space we can actually use it instead of somebody else
4862          * stealing it from us.
4863          *
4864          * We make the other tasks wait for the flush only when we can flush
4865          * all things.
4866          */
4867         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4868                 flushing = true;
4869                 space_info->flush = 1;
4870         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
4871                 used += orig_bytes;
4872                 /*
4873                  * We will do the space reservation dance during log replay,
4874                  * which means we won't have fs_info->fs_root set, so don't do
4875                  * the async reclaim as we will panic.
4876                  */
4877                 if (!root->fs_info->log_root_recovering &&
4878                     need_do_async_reclaim(space_info, root->fs_info, used) &&
4879                     !work_busy(&root->fs_info->async_reclaim_work))
4880                         queue_work(system_unbound_wq,
4881                                    &root->fs_info->async_reclaim_work);
4882         }
4883         spin_unlock(&space_info->lock);
4884
4885         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4886                 goto out;
4887
4888         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4889                           flush_state);
4890         flush_state++;
4891
4892         /*
4893          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4894          * would happen. So skip delalloc flush.
4895          */
4896         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4897             (flush_state == FLUSH_DELALLOC ||
4898              flush_state == FLUSH_DELALLOC_WAIT))
4899                 flush_state = ALLOC_CHUNK;
4900
4901         if (!ret)
4902                 goto again;
4903         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4904                  flush_state < COMMIT_TRANS)
4905                 goto again;
4906         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4907                  flush_state <= COMMIT_TRANS)
4908                 goto again;
4909
4910 out:
4911         if (ret == -ENOSPC &&
4912             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4913                 struct btrfs_block_rsv *global_rsv =
4914                         &root->fs_info->global_block_rsv;
4915
4916                 if (block_rsv != global_rsv &&
4917                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4918                         ret = 0;
4919         }
4920         if (ret == -ENOSPC)
4921                 trace_btrfs_space_reservation(root->fs_info,
4922                                               "space_info:enospc",
4923                                               space_info->flags, orig_bytes, 1);
4924         if (flushing) {
4925                 spin_lock(&space_info->lock);
4926                 space_info->flush = 0;
4927                 wake_up_all(&space_info->wait);
4928                 spin_unlock(&space_info->lock);
4929         }
4930         return ret;
4931 }
4932
4933 static struct btrfs_block_rsv *get_block_rsv(
4934                                         const struct btrfs_trans_handle *trans,
4935                                         const struct btrfs_root *root)
4936 {
4937         struct btrfs_block_rsv *block_rsv = NULL;
4938
4939         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
4940             (root == root->fs_info->csum_root && trans->adding_csums) ||
4941              (root == root->fs_info->uuid_root))
4942                 block_rsv = trans->block_rsv;
4943
4944         if (!block_rsv)
4945                 block_rsv = root->block_rsv;
4946
4947         if (!block_rsv)
4948                 block_rsv = &root->fs_info->empty_block_rsv;
4949
4950         return block_rsv;
4951 }
4952
4953 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4954                                u64 num_bytes)
4955 {
4956         int ret = -ENOSPC;
4957         spin_lock(&block_rsv->lock);
4958         if (block_rsv->reserved >= num_bytes) {
4959                 block_rsv->reserved -= num_bytes;
4960                 if (block_rsv->reserved < block_rsv->size)
4961                         block_rsv->full = 0;
4962                 ret = 0;
4963         }
4964         spin_unlock(&block_rsv->lock);
4965         return ret;
4966 }
4967
4968 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4969                                 u64 num_bytes, int update_size)
4970 {
4971         spin_lock(&block_rsv->lock);
4972         block_rsv->reserved += num_bytes;
4973         if (update_size)
4974                 block_rsv->size += num_bytes;
4975         else if (block_rsv->reserved >= block_rsv->size)
4976                 block_rsv->full = 1;
4977         spin_unlock(&block_rsv->lock);
4978 }
4979
4980 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4981                              struct btrfs_block_rsv *dest, u64 num_bytes,
4982                              int min_factor)
4983 {
4984         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4985         u64 min_bytes;
4986
4987         if (global_rsv->space_info != dest->space_info)
4988                 return -ENOSPC;
4989
4990         spin_lock(&global_rsv->lock);
4991         min_bytes = div_factor(global_rsv->size, min_factor);
4992         if (global_rsv->reserved < min_bytes + num_bytes) {
4993                 spin_unlock(&global_rsv->lock);
4994                 return -ENOSPC;
4995         }
4996         global_rsv->reserved -= num_bytes;
4997         if (global_rsv->reserved < global_rsv->size)
4998                 global_rsv->full = 0;
4999         spin_unlock(&global_rsv->lock);
5000
5001         block_rsv_add_bytes(dest, num_bytes, 1);
5002         return 0;
5003 }
5004
5005 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5006                                     struct btrfs_block_rsv *block_rsv,
5007                                     struct btrfs_block_rsv *dest, u64 num_bytes)
5008 {
5009         struct btrfs_space_info *space_info = block_rsv->space_info;
5010
5011         spin_lock(&block_rsv->lock);
5012         if (num_bytes == (u64)-1)
5013                 num_bytes = block_rsv->size;
5014         block_rsv->size -= num_bytes;
5015         if (block_rsv->reserved >= block_rsv->size) {
5016                 num_bytes = block_rsv->reserved - block_rsv->size;
5017                 block_rsv->reserved = block_rsv->size;
5018                 block_rsv->full = 1;
5019         } else {
5020                 num_bytes = 0;
5021         }
5022         spin_unlock(&block_rsv->lock);
5023
5024         if (num_bytes > 0) {
5025                 if (dest) {
5026                         spin_lock(&dest->lock);
5027                         if (!dest->full) {
5028                                 u64 bytes_to_add;
5029
5030                                 bytes_to_add = dest->size - dest->reserved;
5031                                 bytes_to_add = min(num_bytes, bytes_to_add);
5032                                 dest->reserved += bytes_to_add;
5033                                 if (dest->reserved >= dest->size)
5034                                         dest->full = 1;
5035                                 num_bytes -= bytes_to_add;
5036                         }
5037                         spin_unlock(&dest->lock);
5038                 }
5039                 if (num_bytes) {
5040                         spin_lock(&space_info->lock);
5041                         space_info->bytes_may_use -= num_bytes;
5042                         trace_btrfs_space_reservation(fs_info, "space_info",
5043                                         space_info->flags, num_bytes, 0);
5044                         spin_unlock(&space_info->lock);
5045                 }
5046         }
5047 }
5048
5049 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
5050                                    struct btrfs_block_rsv *dst, u64 num_bytes)
5051 {
5052         int ret;
5053
5054         ret = block_rsv_use_bytes(src, num_bytes);
5055         if (ret)
5056                 return ret;
5057
5058         block_rsv_add_bytes(dst, num_bytes, 1);
5059         return 0;
5060 }
5061
5062 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5063 {
5064         memset(rsv, 0, sizeof(*rsv));
5065         spin_lock_init(&rsv->lock);
5066         rsv->type = type;
5067 }
5068
5069 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
5070                                               unsigned short type)
5071 {
5072         struct btrfs_block_rsv *block_rsv;
5073         struct btrfs_fs_info *fs_info = root->fs_info;
5074
5075         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5076         if (!block_rsv)
5077                 return NULL;
5078
5079         btrfs_init_block_rsv(block_rsv, type);
5080         block_rsv->space_info = __find_space_info(fs_info,
5081                                                   BTRFS_BLOCK_GROUP_METADATA);
5082         return block_rsv;
5083 }
5084
5085 void btrfs_free_block_rsv(struct btrfs_root *root,
5086                           struct btrfs_block_rsv *rsv)
5087 {
5088         if (!rsv)
5089                 return;
5090         btrfs_block_rsv_release(root, rsv, (u64)-1);
5091         kfree(rsv);
5092 }
5093
5094 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5095 {
5096         kfree(rsv);
5097 }
5098
5099 int btrfs_block_rsv_add(struct btrfs_root *root,
5100                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5101                         enum btrfs_reserve_flush_enum flush)
5102 {
5103         int ret;
5104
5105         if (num_bytes == 0)
5106                 return 0;
5107
5108         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5109         if (!ret) {
5110                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5111                 return 0;
5112         }
5113
5114         return ret;
5115 }
5116
5117 int btrfs_block_rsv_check(struct btrfs_root *root,
5118                           struct btrfs_block_rsv *block_rsv, int min_factor)
5119 {
5120         u64 num_bytes = 0;
5121         int ret = -ENOSPC;
5122
5123         if (!block_rsv)
5124                 return 0;
5125
5126         spin_lock(&block_rsv->lock);
5127         num_bytes = div_factor(block_rsv->size, min_factor);
5128         if (block_rsv->reserved >= num_bytes)
5129                 ret = 0;
5130         spin_unlock(&block_rsv->lock);
5131
5132         return ret;
5133 }
5134
5135 int btrfs_block_rsv_refill(struct btrfs_root *root,
5136                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5137                            enum btrfs_reserve_flush_enum flush)
5138 {
5139         u64 num_bytes = 0;
5140         int ret = -ENOSPC;
5141
5142         if (!block_rsv)
5143                 return 0;
5144
5145         spin_lock(&block_rsv->lock);
5146         num_bytes = min_reserved;
5147         if (block_rsv->reserved >= num_bytes)
5148                 ret = 0;
5149         else
5150                 num_bytes -= block_rsv->reserved;
5151         spin_unlock(&block_rsv->lock);
5152
5153         if (!ret)
5154                 return 0;
5155
5156         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5157         if (!ret) {
5158                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5159                 return 0;
5160         }
5161
5162         return ret;
5163 }
5164
5165 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
5166                             struct btrfs_block_rsv *dst_rsv,
5167                             u64 num_bytes)
5168 {
5169         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5170 }
5171
5172 void btrfs_block_rsv_release(struct btrfs_root *root,
5173                              struct btrfs_block_rsv *block_rsv,
5174                              u64 num_bytes)
5175 {
5176         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5177         if (global_rsv == block_rsv ||
5178             block_rsv->space_info != global_rsv->space_info)
5179                 global_rsv = NULL;
5180         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
5181                                 num_bytes);
5182 }
5183
5184 /*
5185  * helper to calculate size of global block reservation.
5186  * the desired value is sum of space used by extent tree,
5187  * checksum tree and root tree
5188  */
5189 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
5190 {
5191         struct btrfs_space_info *sinfo;
5192         u64 num_bytes;
5193         u64 meta_used;
5194         u64 data_used;
5195         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
5196
5197         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
5198         spin_lock(&sinfo->lock);
5199         data_used = sinfo->bytes_used;
5200         spin_unlock(&sinfo->lock);
5201
5202         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5203         spin_lock(&sinfo->lock);
5204         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
5205                 data_used = 0;
5206         meta_used = sinfo->bytes_used;
5207         spin_unlock(&sinfo->lock);
5208
5209         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
5210                     csum_size * 2;
5211         num_bytes += div_u64(data_used + meta_used, 50);
5212
5213         if (num_bytes * 3 > meta_used)
5214                 num_bytes = div_u64(meta_used, 3);
5215
5216         return ALIGN(num_bytes, fs_info->extent_root->nodesize << 10);
5217 }
5218
5219 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5220 {
5221         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5222         struct btrfs_space_info *sinfo = block_rsv->space_info;
5223         u64 num_bytes;
5224
5225         num_bytes = calc_global_metadata_size(fs_info);
5226
5227         spin_lock(&sinfo->lock);
5228         spin_lock(&block_rsv->lock);
5229
5230         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
5231
5232         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
5233                     sinfo->bytes_reserved + sinfo->bytes_readonly +
5234                     sinfo->bytes_may_use;
5235
5236         if (sinfo->total_bytes > num_bytes) {
5237                 num_bytes = sinfo->total_bytes - num_bytes;
5238                 block_rsv->reserved += num_bytes;
5239                 sinfo->bytes_may_use += num_bytes;
5240                 trace_btrfs_space_reservation(fs_info, "space_info",
5241                                       sinfo->flags, num_bytes, 1);
5242         }
5243
5244         if (block_rsv->reserved >= block_rsv->size) {
5245                 num_bytes = block_rsv->reserved - block_rsv->size;
5246                 sinfo->bytes_may_use -= num_bytes;
5247                 trace_btrfs_space_reservation(fs_info, "space_info",
5248                                       sinfo->flags, num_bytes, 0);
5249                 block_rsv->reserved = block_rsv->size;
5250                 block_rsv->full = 1;
5251         }
5252
5253         spin_unlock(&block_rsv->lock);
5254         spin_unlock(&sinfo->lock);
5255 }
5256
5257 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5258 {
5259         struct btrfs_space_info *space_info;
5260
5261         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5262         fs_info->chunk_block_rsv.space_info = space_info;
5263
5264         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5265         fs_info->global_block_rsv.space_info = space_info;
5266         fs_info->delalloc_block_rsv.space_info = space_info;
5267         fs_info->trans_block_rsv.space_info = space_info;
5268         fs_info->empty_block_rsv.space_info = space_info;
5269         fs_info->delayed_block_rsv.space_info = space_info;
5270
5271         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5272         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5273         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5274         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5275         if (fs_info->quota_root)
5276                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5277         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5278
5279         update_global_block_rsv(fs_info);
5280 }
5281
5282 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5283 {
5284         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5285                                 (u64)-1);
5286         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5287         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5288         WARN_ON(fs_info->trans_block_rsv.size > 0);
5289         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5290         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5291         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5292         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5293         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5294 }
5295
5296 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5297                                   struct btrfs_root *root)
5298 {
5299         if (!trans->block_rsv)
5300                 return;
5301
5302         if (!trans->bytes_reserved)
5303                 return;
5304
5305         trace_btrfs_space_reservation(root->fs_info, "transaction",
5306                                       trans->transid, trans->bytes_reserved, 0);
5307         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
5308         trans->bytes_reserved = 0;
5309 }
5310
5311 /*
5312  * To be called after all the new block groups attached to the transaction
5313  * handle have been created (btrfs_create_pending_block_groups()).
5314  */
5315 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5316 {
5317         struct btrfs_fs_info *fs_info = trans->root->fs_info;
5318
5319         if (!trans->chunk_bytes_reserved)
5320                 return;
5321
5322         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5323
5324         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5325                                 trans->chunk_bytes_reserved);
5326         trans->chunk_bytes_reserved = 0;
5327 }
5328
5329 /* Can only return 0 or -ENOSPC */
5330 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5331                                   struct inode *inode)
5332 {
5333         struct btrfs_root *root = BTRFS_I(inode)->root;
5334         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
5335         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5336
5337         /*
5338          * We need to hold space in order to delete our orphan item once we've
5339          * added it, so this takes the reservation so we can release it later
5340          * when we are truly done with the orphan item.
5341          */
5342         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5343         trace_btrfs_space_reservation(root->fs_info, "orphan",
5344                                       btrfs_ino(inode), num_bytes, 1);
5345         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
5346 }
5347
5348 void btrfs_orphan_release_metadata(struct inode *inode)
5349 {
5350         struct btrfs_root *root = BTRFS_I(inode)->root;
5351         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
5352         trace_btrfs_space_reservation(root->fs_info, "orphan",
5353                                       btrfs_ino(inode), num_bytes, 0);
5354         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
5355 }
5356
5357 /*
5358  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5359  * root: the root of the parent directory
5360  * rsv: block reservation
5361  * items: the number of items that we need do reservation
5362  * qgroup_reserved: used to return the reserved size in qgroup
5363  *
5364  * This function is used to reserve the space for snapshot/subvolume
5365  * creation and deletion. Those operations are different with the
5366  * common file/directory operations, they change two fs/file trees
5367  * and root tree, the number of items that the qgroup reserves is
5368  * different with the free space reservation. So we can not use
5369  * the space reseravtion mechanism in start_transaction().
5370  */
5371 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5372                                      struct btrfs_block_rsv *rsv,
5373                                      int items,
5374                                      u64 *qgroup_reserved,
5375                                      bool use_global_rsv)
5376 {
5377         u64 num_bytes;
5378         int ret;
5379         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
5380
5381         if (root->fs_info->quota_enabled) {
5382                 /* One for parent inode, two for dir entries */
5383                 num_bytes = 3 * root->nodesize;
5384                 ret = btrfs_qgroup_reserve_meta(root, num_bytes);
5385                 if (ret)
5386                         return ret;
5387         } else {
5388                 num_bytes = 0;
5389         }
5390
5391         *qgroup_reserved = num_bytes;
5392
5393         num_bytes = btrfs_calc_trans_metadata_size(root, items);
5394         rsv->space_info = __find_space_info(root->fs_info,
5395                                             BTRFS_BLOCK_GROUP_METADATA);
5396         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5397                                   BTRFS_RESERVE_FLUSH_ALL);
5398
5399         if (ret == -ENOSPC && use_global_rsv)
5400                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
5401
5402         if (ret && *qgroup_reserved)
5403                 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5404
5405         return ret;
5406 }
5407
5408 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
5409                                       struct btrfs_block_rsv *rsv,
5410                                       u64 qgroup_reserved)
5411 {
5412         btrfs_block_rsv_release(root, rsv, (u64)-1);
5413 }
5414
5415 /**
5416  * drop_outstanding_extent - drop an outstanding extent
5417  * @inode: the inode we're dropping the extent for
5418  * @num_bytes: the number of bytes we're relaseing.
5419  *
5420  * This is called when we are freeing up an outstanding extent, either called
5421  * after an error or after an extent is written.  This will return the number of
5422  * reserved extents that need to be freed.  This must be called with
5423  * BTRFS_I(inode)->lock held.
5424  */
5425 static unsigned drop_outstanding_extent(struct inode *inode, u64 num_bytes)
5426 {
5427         unsigned drop_inode_space = 0;
5428         unsigned dropped_extents = 0;
5429         unsigned num_extents = 0;
5430
5431         num_extents = (unsigned)div64_u64(num_bytes +
5432                                           BTRFS_MAX_EXTENT_SIZE - 1,
5433                                           BTRFS_MAX_EXTENT_SIZE);
5434         ASSERT(num_extents);
5435         ASSERT(BTRFS_I(inode)->outstanding_extents >= num_extents);
5436         BTRFS_I(inode)->outstanding_extents -= num_extents;
5437
5438         if (BTRFS_I(inode)->outstanding_extents == 0 &&
5439             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5440                                &BTRFS_I(inode)->runtime_flags))
5441                 drop_inode_space = 1;
5442
5443         /*
5444          * If we have more or the same amount of outsanding extents than we have
5445          * reserved then we need to leave the reserved extents count alone.
5446          */
5447         if (BTRFS_I(inode)->outstanding_extents >=
5448             BTRFS_I(inode)->reserved_extents)
5449                 return drop_inode_space;
5450
5451         dropped_extents = BTRFS_I(inode)->reserved_extents -
5452                 BTRFS_I(inode)->outstanding_extents;
5453         BTRFS_I(inode)->reserved_extents -= dropped_extents;
5454         return dropped_extents + drop_inode_space;
5455 }
5456
5457 /**
5458  * calc_csum_metadata_size - return the amount of metada space that must be
5459  *      reserved/free'd for the given bytes.
5460  * @inode: the inode we're manipulating
5461  * @num_bytes: the number of bytes in question
5462  * @reserve: 1 if we are reserving space, 0 if we are freeing space
5463  *
5464  * This adjusts the number of csum_bytes in the inode and then returns the
5465  * correct amount of metadata that must either be reserved or freed.  We
5466  * calculate how many checksums we can fit into one leaf and then divide the
5467  * number of bytes that will need to be checksumed by this value to figure out
5468  * how many checksums will be required.  If we are adding bytes then the number
5469  * may go up and we will return the number of additional bytes that must be
5470  * reserved.  If it is going down we will return the number of bytes that must
5471  * be freed.
5472  *
5473  * This must be called with BTRFS_I(inode)->lock held.
5474  */
5475 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
5476                                    int reserve)
5477 {
5478         struct btrfs_root *root = BTRFS_I(inode)->root;
5479         u64 old_csums, num_csums;
5480
5481         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
5482             BTRFS_I(inode)->csum_bytes == 0)
5483                 return 0;
5484
5485         old_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5486         if (reserve)
5487                 BTRFS_I(inode)->csum_bytes += num_bytes;
5488         else
5489                 BTRFS_I(inode)->csum_bytes -= num_bytes;
5490         num_csums = btrfs_csum_bytes_to_leaves(root, BTRFS_I(inode)->csum_bytes);
5491
5492         /* No change, no need to reserve more */
5493         if (old_csums == num_csums)
5494                 return 0;
5495
5496         if (reserve)
5497                 return btrfs_calc_trans_metadata_size(root,
5498                                                       num_csums - old_csums);
5499
5500         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
5501 }
5502
5503 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
5504 {
5505         struct btrfs_root *root = BTRFS_I(inode)->root;
5506         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
5507         u64 to_reserve = 0;
5508         u64 csum_bytes;
5509         unsigned nr_extents = 0;
5510         int extra_reserve = 0;
5511         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
5512         int ret = 0;
5513         bool delalloc_lock = true;
5514         u64 to_free = 0;
5515         unsigned dropped;
5516
5517         /* If we are a free space inode we need to not flush since we will be in
5518          * the middle of a transaction commit.  We also don't need the delalloc
5519          * mutex since we won't race with anybody.  We need this mostly to make
5520          * lockdep shut its filthy mouth.
5521          */
5522         if (btrfs_is_free_space_inode(inode)) {
5523                 flush = BTRFS_RESERVE_NO_FLUSH;
5524                 delalloc_lock = false;
5525         }
5526
5527         if (flush != BTRFS_RESERVE_NO_FLUSH &&
5528             btrfs_transaction_in_commit(root->fs_info))
5529                 schedule_timeout(1);
5530
5531         if (delalloc_lock)
5532                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
5533
5534         num_bytes = ALIGN(num_bytes, root->sectorsize);
5535
5536         spin_lock(&BTRFS_I(inode)->lock);
5537         nr_extents = (unsigned)div64_u64(num_bytes +
5538                                          BTRFS_MAX_EXTENT_SIZE - 1,
5539                                          BTRFS_MAX_EXTENT_SIZE);
5540         BTRFS_I(inode)->outstanding_extents += nr_extents;
5541         nr_extents = 0;
5542
5543         if (BTRFS_I(inode)->outstanding_extents >
5544             BTRFS_I(inode)->reserved_extents)
5545                 nr_extents = BTRFS_I(inode)->outstanding_extents -
5546                         BTRFS_I(inode)->reserved_extents;
5547
5548         /*
5549          * Add an item to reserve for updating the inode when we complete the
5550          * delalloc io.
5551          */
5552         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5553                       &BTRFS_I(inode)->runtime_flags)) {
5554                 nr_extents++;
5555                 extra_reserve = 1;
5556         }
5557
5558         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5559         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5560         csum_bytes = BTRFS_I(inode)->csum_bytes;
5561         spin_unlock(&BTRFS_I(inode)->lock);
5562
5563         if (root->fs_info->quota_enabled) {
5564                 ret = btrfs_qgroup_reserve_meta(root,
5565                                 nr_extents * root->nodesize);
5566                 if (ret)
5567                         goto out_fail;
5568         }
5569
5570         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5571         if (unlikely(ret)) {
5572                 btrfs_qgroup_free_meta(root, nr_extents * root->nodesize);
5573                 goto out_fail;
5574         }
5575
5576         spin_lock(&BTRFS_I(inode)->lock);
5577         if (extra_reserve) {
5578                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5579                         &BTRFS_I(inode)->runtime_flags);
5580                 nr_extents--;
5581         }
5582         BTRFS_I(inode)->reserved_extents += nr_extents;
5583         spin_unlock(&BTRFS_I(inode)->lock);
5584
5585         if (delalloc_lock)
5586                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5587
5588         if (to_reserve)
5589                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5590                                               btrfs_ino(inode), to_reserve, 1);
5591         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5592
5593         return 0;
5594
5595 out_fail:
5596         spin_lock(&BTRFS_I(inode)->lock);
5597         dropped = drop_outstanding_extent(inode, num_bytes);
5598         /*
5599          * If the inodes csum_bytes is the same as the original
5600          * csum_bytes then we know we haven't raced with any free()ers
5601          * so we can just reduce our inodes csum bytes and carry on.
5602          */
5603         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5604                 calc_csum_metadata_size(inode, num_bytes, 0);
5605         } else {
5606                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5607                 u64 bytes;
5608
5609                 /*
5610                  * This is tricky, but first we need to figure out how much we
5611                  * free'd from any free-ers that occured during this
5612                  * reservation, so we reset ->csum_bytes to the csum_bytes
5613                  * before we dropped our lock, and then call the free for the
5614                  * number of bytes that were freed while we were trying our
5615                  * reservation.
5616                  */
5617                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5618                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5619                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5620
5621
5622                 /*
5623                  * Now we need to see how much we would have freed had we not
5624                  * been making this reservation and our ->csum_bytes were not
5625                  * artificially inflated.
5626                  */
5627                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5628                 bytes = csum_bytes - orig_csum_bytes;
5629                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5630
5631                 /*
5632                  * Now reset ->csum_bytes to what it should be.  If bytes is
5633                  * more than to_free then we would have free'd more space had we
5634                  * not had an artificially high ->csum_bytes, so we need to free
5635                  * the remainder.  If bytes is the same or less then we don't
5636                  * need to do anything, the other free-ers did the correct
5637                  * thing.
5638                  */
5639                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5640                 if (bytes > to_free)
5641                         to_free = bytes - to_free;
5642                 else
5643                         to_free = 0;
5644         }
5645         spin_unlock(&BTRFS_I(inode)->lock);
5646         if (dropped)
5647                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5648
5649         if (to_free) {
5650                 btrfs_block_rsv_release(root, block_rsv, to_free);
5651                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5652                                               btrfs_ino(inode), to_free, 0);
5653         }
5654         if (delalloc_lock)
5655                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5656         return ret;
5657 }
5658
5659 /**
5660  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5661  * @inode: the inode to release the reservation for
5662  * @num_bytes: the number of bytes we're releasing
5663  *
5664  * This will release the metadata reservation for an inode.  This can be called
5665  * once we complete IO for a given set of bytes to release their metadata
5666  * reservations.
5667  */
5668 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5669 {
5670         struct btrfs_root *root = BTRFS_I(inode)->root;
5671         u64 to_free = 0;
5672         unsigned dropped;
5673
5674         num_bytes = ALIGN(num_bytes, root->sectorsize);
5675         spin_lock(&BTRFS_I(inode)->lock);
5676         dropped = drop_outstanding_extent(inode, num_bytes);
5677
5678         if (num_bytes)
5679                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5680         spin_unlock(&BTRFS_I(inode)->lock);
5681         if (dropped > 0)
5682                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5683
5684         if (btrfs_test_is_dummy_root(root))
5685                 return;
5686
5687         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5688                                       btrfs_ino(inode), to_free, 0);
5689
5690         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5691                                 to_free);
5692 }
5693
5694 /**
5695  * btrfs_delalloc_reserve_space - reserve data and metadata space for
5696  * delalloc
5697  * @inode: inode we're writing to
5698  * @start: start range we are writing to
5699  * @len: how long the range we are writing to
5700  *
5701  * TODO: This function will finally replace old btrfs_delalloc_reserve_space()
5702  *
5703  * This will do the following things
5704  *
5705  * o reserve space in data space info for num bytes
5706  *   and reserve precious corresponding qgroup space
5707  *   (Done in check_data_free_space)
5708  *
5709  * o reserve space for metadata space, based on the number of outstanding
5710  *   extents and how much csums will be needed
5711  *   also reserve metadata space in a per root over-reserve method.
5712  * o add to the inodes->delalloc_bytes
5713  * o add it to the fs_info's delalloc inodes list.
5714  *   (Above 3 all done in delalloc_reserve_metadata)
5715  *
5716  * Return 0 for success
5717  * Return <0 for error(-ENOSPC or -EQUOT)
5718  */
5719 int btrfs_delalloc_reserve_space(struct inode *inode, u64 start, u64 len)
5720 {
5721         int ret;
5722
5723         ret = btrfs_check_data_free_space(inode, start, len);
5724         if (ret < 0)
5725                 return ret;
5726         ret = btrfs_delalloc_reserve_metadata(inode, len);
5727         if (ret < 0)
5728                 btrfs_free_reserved_data_space(inode, start, len);
5729         return ret;
5730 }
5731
5732 /**
5733  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5734  * @inode: inode we're releasing space for
5735  * @start: start position of the space already reserved
5736  * @len: the len of the space already reserved
5737  *
5738  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5739  * called in the case that we don't need the metadata AND data reservations
5740  * anymore.  So if there is an error or we insert an inline extent.
5741  *
5742  * This function will release the metadata space that was not used and will
5743  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5744  * list if there are no delalloc bytes left.
5745  * Also it will handle the qgroup reserved space.
5746  */
5747 void btrfs_delalloc_release_space(struct inode *inode, u64 start, u64 len)
5748 {
5749         btrfs_delalloc_release_metadata(inode, len);
5750         btrfs_free_reserved_data_space(inode, start, len);
5751 }
5752
5753 static int update_block_group(struct btrfs_trans_handle *trans,
5754                               struct btrfs_root *root, u64 bytenr,
5755                               u64 num_bytes, int alloc)
5756 {
5757         struct btrfs_block_group_cache *cache = NULL;
5758         struct btrfs_fs_info *info = root->fs_info;
5759         u64 total = num_bytes;
5760         u64 old_val;
5761         u64 byte_in_group;
5762         int factor;
5763
5764         /* block accounting for super block */
5765         spin_lock(&info->delalloc_root_lock);
5766         old_val = btrfs_super_bytes_used(info->super_copy);
5767         if (alloc)
5768                 old_val += num_bytes;
5769         else
5770                 old_val -= num_bytes;
5771         btrfs_set_super_bytes_used(info->super_copy, old_val);
5772         spin_unlock(&info->delalloc_root_lock);
5773
5774         while (total) {
5775                 cache = btrfs_lookup_block_group(info, bytenr);
5776                 if (!cache)
5777                         return -ENOENT;
5778                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5779                                     BTRFS_BLOCK_GROUP_RAID1 |
5780                                     BTRFS_BLOCK_GROUP_RAID10))
5781                         factor = 2;
5782                 else
5783                         factor = 1;
5784                 /*
5785                  * If this block group has free space cache written out, we
5786                  * need to make sure to load it if we are removing space.  This
5787                  * is because we need the unpinning stage to actually add the
5788                  * space back to the block group, otherwise we will leak space.
5789                  */
5790                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5791                         cache_block_group(cache, 1);
5792
5793                 byte_in_group = bytenr - cache->key.objectid;
5794                 WARN_ON(byte_in_group > cache->key.offset);
5795
5796                 spin_lock(&cache->space_info->lock);
5797                 spin_lock(&cache->lock);
5798
5799                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5800                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5801                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5802
5803                 old_val = btrfs_block_group_used(&cache->item);
5804                 num_bytes = min(total, cache->key.offset - byte_in_group);
5805                 if (alloc) {
5806                         old_val += num_bytes;
5807                         btrfs_set_block_group_used(&cache->item, old_val);
5808                         cache->reserved -= num_bytes;
5809                         cache->space_info->bytes_reserved -= num_bytes;
5810                         cache->space_info->bytes_used += num_bytes;
5811                         cache->space_info->disk_used += num_bytes * factor;
5812                         spin_unlock(&cache->lock);
5813                         spin_unlock(&cache->space_info->lock);
5814                 } else {
5815                         old_val -= num_bytes;
5816                         btrfs_set_block_group_used(&cache->item, old_val);
5817                         cache->pinned += num_bytes;
5818                         cache->space_info->bytes_pinned += num_bytes;
5819                         cache->space_info->bytes_used -= num_bytes;
5820                         cache->space_info->disk_used -= num_bytes * factor;
5821                         spin_unlock(&cache->lock);
5822                         spin_unlock(&cache->space_info->lock);
5823
5824                         set_extent_dirty(info->pinned_extents,
5825                                          bytenr, bytenr + num_bytes - 1,
5826                                          GFP_NOFS | __GFP_NOFAIL);
5827                         /*
5828                          * No longer have used bytes in this block group, queue
5829                          * it for deletion.
5830                          */
5831                         if (old_val == 0) {
5832                                 spin_lock(&info->unused_bgs_lock);
5833                                 if (list_empty(&cache->bg_list)) {
5834                                         btrfs_get_block_group(cache);
5835                                         list_add_tail(&cache->bg_list,
5836                                                       &info->unused_bgs);
5837                                 }
5838                                 spin_unlock(&info->unused_bgs_lock);
5839                         }
5840                 }
5841
5842                 spin_lock(&trans->transaction->dirty_bgs_lock);
5843                 if (list_empty(&cache->dirty_list)) {
5844                         list_add_tail(&cache->dirty_list,
5845                                       &trans->transaction->dirty_bgs);
5846                                 trans->transaction->num_dirty_bgs++;
5847                         btrfs_get_block_group(cache);
5848                 }
5849                 spin_unlock(&trans->transaction->dirty_bgs_lock);
5850
5851                 btrfs_put_block_group(cache);
5852                 total -= num_bytes;
5853                 bytenr += num_bytes;
5854         }
5855         return 0;
5856 }
5857
5858 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5859 {
5860         struct btrfs_block_group_cache *cache;
5861         u64 bytenr;
5862
5863         spin_lock(&root->fs_info->block_group_cache_lock);
5864         bytenr = root->fs_info->first_logical_byte;
5865         spin_unlock(&root->fs_info->block_group_cache_lock);
5866
5867         if (bytenr < (u64)-1)
5868                 return bytenr;
5869
5870         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5871         if (!cache)
5872                 return 0;
5873
5874         bytenr = cache->key.objectid;
5875         btrfs_put_block_group(cache);
5876
5877         return bytenr;
5878 }
5879
5880 static int pin_down_extent(struct btrfs_root *root,
5881                            struct btrfs_block_group_cache *cache,
5882                            u64 bytenr, u64 num_bytes, int reserved)
5883 {
5884         spin_lock(&cache->space_info->lock);
5885         spin_lock(&cache->lock);
5886         cache->pinned += num_bytes;
5887         cache->space_info->bytes_pinned += num_bytes;
5888         if (reserved) {
5889                 cache->reserved -= num_bytes;
5890                 cache->space_info->bytes_reserved -= num_bytes;
5891         }
5892         spin_unlock(&cache->lock);
5893         spin_unlock(&cache->space_info->lock);
5894
5895         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5896                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5897         if (reserved)
5898                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
5899         return 0;
5900 }
5901
5902 /*
5903  * this function must be called within transaction
5904  */
5905 int btrfs_pin_extent(struct btrfs_root *root,
5906                      u64 bytenr, u64 num_bytes, int reserved)
5907 {
5908         struct btrfs_block_group_cache *cache;
5909
5910         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5911         BUG_ON(!cache); /* Logic error */
5912
5913         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5914
5915         btrfs_put_block_group(cache);
5916         return 0;
5917 }
5918
5919 /*
5920  * this function must be called within transaction
5921  */
5922 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5923                                     u64 bytenr, u64 num_bytes)
5924 {
5925         struct btrfs_block_group_cache *cache;
5926         int ret;
5927
5928         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5929         if (!cache)
5930                 return -EINVAL;
5931
5932         /*
5933          * pull in the free space cache (if any) so that our pin
5934          * removes the free space from the cache.  We have load_only set
5935          * to one because the slow code to read in the free extents does check
5936          * the pinned extents.
5937          */
5938         cache_block_group(cache, 1);
5939
5940         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5941
5942         /* remove us from the free space cache (if we're there at all) */
5943         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5944         btrfs_put_block_group(cache);
5945         return ret;
5946 }
5947
5948 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5949 {
5950         int ret;
5951         struct btrfs_block_group_cache *block_group;
5952         struct btrfs_caching_control *caching_ctl;
5953
5954         block_group = btrfs_lookup_block_group(root->fs_info, start);
5955         if (!block_group)
5956                 return -EINVAL;
5957
5958         cache_block_group(block_group, 0);
5959         caching_ctl = get_caching_control(block_group);
5960
5961         if (!caching_ctl) {
5962                 /* Logic error */
5963                 BUG_ON(!block_group_cache_done(block_group));
5964                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5965         } else {
5966                 mutex_lock(&caching_ctl->mutex);
5967
5968                 if (start >= caching_ctl->progress) {
5969                         ret = add_excluded_extent(root, start, num_bytes);
5970                 } else if (start + num_bytes <= caching_ctl->progress) {
5971                         ret = btrfs_remove_free_space(block_group,
5972                                                       start, num_bytes);
5973                 } else {
5974                         num_bytes = caching_ctl->progress - start;
5975                         ret = btrfs_remove_free_space(block_group,
5976                                                       start, num_bytes);
5977                         if (ret)
5978                                 goto out_lock;
5979
5980                         num_bytes = (start + num_bytes) -
5981                                 caching_ctl->progress;
5982                         start = caching_ctl->progress;
5983                         ret = add_excluded_extent(root, start, num_bytes);
5984                 }
5985 out_lock:
5986                 mutex_unlock(&caching_ctl->mutex);
5987                 put_caching_control(caching_ctl);
5988         }
5989         btrfs_put_block_group(block_group);
5990         return ret;
5991 }
5992
5993 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5994                                  struct extent_buffer *eb)
5995 {
5996         struct btrfs_file_extent_item *item;
5997         struct btrfs_key key;
5998         int found_type;
5999         int i;
6000
6001         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
6002                 return 0;
6003
6004         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6005                 btrfs_item_key_to_cpu(eb, &key, i);
6006                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6007                         continue;
6008                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6009                 found_type = btrfs_file_extent_type(eb, item);
6010                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6011                         continue;
6012                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6013                         continue;
6014                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6015                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6016                 __exclude_logged_extent(log, key.objectid, key.offset);
6017         }
6018
6019         return 0;
6020 }
6021
6022 /**
6023  * btrfs_update_reserved_bytes - update the block_group and space info counters
6024  * @cache:      The cache we are manipulating
6025  * @num_bytes:  The number of bytes in question
6026  * @reserve:    One of the reservation enums
6027  * @delalloc:   The blocks are allocated for the delalloc write
6028  *
6029  * This is called by the allocator when it reserves space, or by somebody who is
6030  * freeing space that was never actually used on disk.  For example if you
6031  * reserve some space for a new leaf in transaction A and before transaction A
6032  * commits you free that leaf, you call this with reserve set to 0 in order to
6033  * clear the reservation.
6034  *
6035  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
6036  * ENOSPC accounting.  For data we handle the reservation through clearing the
6037  * delalloc bits in the io_tree.  We have to do this since we could end up
6038  * allocating less disk space for the amount of data we have reserved in the
6039  * case of compression.
6040  *
6041  * If this is a reservation and the block group has become read only we cannot
6042  * make the reservation and return -EAGAIN, otherwise this function always
6043  * succeeds.
6044  */
6045 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
6046                                        u64 num_bytes, int reserve, int delalloc)
6047 {
6048         struct btrfs_space_info *space_info = cache->space_info;
6049         int ret = 0;
6050
6051         spin_lock(&space_info->lock);
6052         spin_lock(&cache->lock);
6053         if (reserve != RESERVE_FREE) {
6054                 if (cache->ro) {
6055                         ret = -EAGAIN;
6056                 } else {
6057                         cache->reserved += num_bytes;
6058                         space_info->bytes_reserved += num_bytes;
6059                         if (reserve == RESERVE_ALLOC) {
6060                                 trace_btrfs_space_reservation(cache->fs_info,
6061                                                 "space_info", space_info->flags,
6062                                                 num_bytes, 0);
6063                                 space_info->bytes_may_use -= num_bytes;
6064                         }
6065
6066                         if (delalloc)
6067                                 cache->delalloc_bytes += num_bytes;
6068                 }
6069         } else {
6070                 if (cache->ro)
6071                         space_info->bytes_readonly += num_bytes;
6072                 cache->reserved -= num_bytes;
6073                 space_info->bytes_reserved -= num_bytes;
6074
6075                 if (delalloc)
6076                         cache->delalloc_bytes -= num_bytes;
6077         }
6078         spin_unlock(&cache->lock);
6079         spin_unlock(&space_info->lock);
6080         return ret;
6081 }
6082
6083 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
6084                                 struct btrfs_root *root)
6085 {
6086         struct btrfs_fs_info *fs_info = root->fs_info;
6087         struct btrfs_caching_control *next;
6088         struct btrfs_caching_control *caching_ctl;
6089         struct btrfs_block_group_cache *cache;
6090
6091         down_write(&fs_info->commit_root_sem);
6092
6093         list_for_each_entry_safe(caching_ctl, next,
6094                                  &fs_info->caching_block_groups, list) {
6095                 cache = caching_ctl->block_group;
6096                 if (block_group_cache_done(cache)) {
6097                         cache->last_byte_to_unpin = (u64)-1;
6098                         list_del_init(&caching_ctl->list);
6099                         put_caching_control(caching_ctl);
6100                 } else {
6101                         cache->last_byte_to_unpin = caching_ctl->progress;
6102                 }
6103         }
6104
6105         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6106                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6107         else
6108                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6109
6110         up_write(&fs_info->commit_root_sem);
6111
6112         update_global_block_rsv(fs_info);
6113 }
6114
6115 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end,
6116                               const bool return_free_space)
6117 {
6118         struct btrfs_fs_info *fs_info = root->fs_info;
6119         struct btrfs_block_group_cache *cache = NULL;
6120         struct btrfs_space_info *space_info;
6121         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6122         u64 len;
6123         bool readonly;
6124
6125         while (start <= end) {
6126                 readonly = false;
6127                 if (!cache ||
6128                     start >= cache->key.objectid + cache->key.offset) {
6129                         if (cache)
6130                                 btrfs_put_block_group(cache);
6131                         cache = btrfs_lookup_block_group(fs_info, start);
6132                         BUG_ON(!cache); /* Logic error */
6133                 }
6134
6135                 len = cache->key.objectid + cache->key.offset - start;
6136                 len = min(len, end + 1 - start);
6137
6138                 if (start < cache->last_byte_to_unpin) {
6139                         len = min(len, cache->last_byte_to_unpin - start);
6140                         if (return_free_space)
6141                                 btrfs_add_free_space(cache, start, len);
6142                 }
6143
6144                 start += len;
6145                 space_info = cache->space_info;
6146
6147                 spin_lock(&space_info->lock);
6148                 spin_lock(&cache->lock);
6149                 cache->pinned -= len;
6150                 space_info->bytes_pinned -= len;
6151                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6152                 if (cache->ro) {
6153                         space_info->bytes_readonly += len;
6154                         readonly = true;
6155                 }
6156                 spin_unlock(&cache->lock);
6157                 if (!readonly && global_rsv->space_info == space_info) {
6158                         spin_lock(&global_rsv->lock);
6159                         if (!global_rsv->full) {
6160                                 len = min(len, global_rsv->size -
6161                                           global_rsv->reserved);
6162                                 global_rsv->reserved += len;
6163                                 space_info->bytes_may_use += len;
6164                                 if (global_rsv->reserved >= global_rsv->size)
6165                                         global_rsv->full = 1;
6166                         }
6167                         spin_unlock(&global_rsv->lock);
6168                 }
6169                 spin_unlock(&space_info->lock);
6170         }
6171
6172         if (cache)
6173                 btrfs_put_block_group(cache);
6174         return 0;
6175 }
6176
6177 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6178                                struct btrfs_root *root)
6179 {
6180         struct btrfs_fs_info *fs_info = root->fs_info;
6181         struct btrfs_block_group_cache *block_group, *tmp;
6182         struct list_head *deleted_bgs;
6183         struct extent_io_tree *unpin;
6184         u64 start;
6185         u64 end;
6186         int ret;
6187
6188         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6189                 unpin = &fs_info->freed_extents[1];
6190         else
6191                 unpin = &fs_info->freed_extents[0];
6192
6193         while (!trans->aborted) {
6194                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6195                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6196                                             EXTENT_DIRTY, NULL);
6197                 if (ret) {
6198                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6199                         break;
6200                 }
6201
6202                 if (btrfs_test_opt(root, DISCARD))
6203                         ret = btrfs_discard_extent(root, start,
6204                                                    end + 1 - start, NULL);
6205
6206                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
6207                 unpin_extent_range(root, start, end, true);
6208                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6209                 cond_resched();
6210         }
6211
6212         /*
6213          * Transaction is finished.  We don't need the lock anymore.  We
6214          * do need to clean up the block groups in case of a transaction
6215          * abort.
6216          */
6217         deleted_bgs = &trans->transaction->deleted_bgs;
6218         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6219                 u64 trimmed = 0;
6220
6221                 ret = -EROFS;
6222                 if (!trans->aborted)
6223                         ret = btrfs_discard_extent(root,
6224                                                    block_group->key.objectid,
6225                                                    block_group->key.offset,
6226                                                    &trimmed);
6227
6228                 list_del_init(&block_group->bg_list);
6229                 btrfs_put_block_group_trimming(block_group);
6230                 btrfs_put_block_group(block_group);
6231
6232                 if (ret) {
6233                         const char *errstr = btrfs_decode_error(ret);
6234                         btrfs_warn(fs_info,
6235                                    "Discard failed while removing blockgroup: errno=%d %s\n",
6236                                    ret, errstr);
6237                 }
6238         }
6239
6240         return 0;
6241 }
6242
6243 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
6244                              u64 owner, u64 root_objectid)
6245 {
6246         struct btrfs_space_info *space_info;
6247         u64 flags;
6248
6249         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6250                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
6251                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
6252                 else
6253                         flags = BTRFS_BLOCK_GROUP_METADATA;
6254         } else {
6255                 flags = BTRFS_BLOCK_GROUP_DATA;
6256         }
6257
6258         space_info = __find_space_info(fs_info, flags);
6259         BUG_ON(!space_info); /* Logic bug */
6260         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
6261 }
6262
6263
6264 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6265                                 struct btrfs_root *root,
6266                                 struct btrfs_delayed_ref_node *node, u64 parent,
6267                                 u64 root_objectid, u64 owner_objectid,
6268                                 u64 owner_offset, int refs_to_drop,
6269                                 struct btrfs_delayed_extent_op *extent_op)
6270 {
6271         struct btrfs_key key;
6272         struct btrfs_path *path;
6273         struct btrfs_fs_info *info = root->fs_info;
6274         struct btrfs_root *extent_root = info->extent_root;
6275         struct extent_buffer *leaf;
6276         struct btrfs_extent_item *ei;
6277         struct btrfs_extent_inline_ref *iref;
6278         int ret;
6279         int is_data;
6280         int extent_slot = 0;
6281         int found_extent = 0;
6282         int num_to_del = 1;
6283         int no_quota = node->no_quota;
6284         u32 item_size;
6285         u64 refs;
6286         u64 bytenr = node->bytenr;
6287         u64 num_bytes = node->num_bytes;
6288         int last_ref = 0;
6289         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6290                                                  SKINNY_METADATA);
6291
6292         if (!info->quota_enabled || !is_fstree(root_objectid))
6293                 no_quota = 1;
6294
6295         path = btrfs_alloc_path();
6296         if (!path)
6297                 return -ENOMEM;
6298
6299         path->reada = 1;
6300         path->leave_spinning = 1;
6301
6302         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6303         BUG_ON(!is_data && refs_to_drop != 1);
6304
6305         if (is_data)
6306                 skinny_metadata = 0;
6307
6308         ret = lookup_extent_backref(trans, extent_root, path, &iref,
6309                                     bytenr, num_bytes, parent,
6310                                     root_objectid, owner_objectid,
6311                                     owner_offset);
6312         if (ret == 0) {
6313                 extent_slot = path->slots[0];
6314                 while (extent_slot >= 0) {
6315                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6316                                               extent_slot);
6317                         if (key.objectid != bytenr)
6318                                 break;
6319                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
6320                             key.offset == num_bytes) {
6321                                 found_extent = 1;
6322                                 break;
6323                         }
6324                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
6325                             key.offset == owner_objectid) {
6326                                 found_extent = 1;
6327                                 break;
6328                         }
6329                         if (path->slots[0] - extent_slot > 5)
6330                                 break;
6331                         extent_slot--;
6332                 }
6333 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6334                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
6335                 if (found_extent && item_size < sizeof(*ei))
6336                         found_extent = 0;
6337 #endif
6338                 if (!found_extent) {
6339                         BUG_ON(iref);
6340                         ret = remove_extent_backref(trans, extent_root, path,
6341                                                     NULL, refs_to_drop,
6342                                                     is_data, &last_ref);
6343                         if (ret) {
6344                                 btrfs_abort_transaction(trans, extent_root, ret);
6345                                 goto out;
6346                         }
6347                         btrfs_release_path(path);
6348                         path->leave_spinning = 1;
6349
6350                         key.objectid = bytenr;
6351                         key.type = BTRFS_EXTENT_ITEM_KEY;
6352                         key.offset = num_bytes;
6353
6354                         if (!is_data && skinny_metadata) {
6355                                 key.type = BTRFS_METADATA_ITEM_KEY;
6356                                 key.offset = owner_objectid;
6357                         }
6358
6359                         ret = btrfs_search_slot(trans, extent_root,
6360                                                 &key, path, -1, 1);
6361                         if (ret > 0 && skinny_metadata && path->slots[0]) {
6362                                 /*
6363                                  * Couldn't find our skinny metadata item,
6364                                  * see if we have ye olde extent item.
6365                                  */
6366                                 path->slots[0]--;
6367                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
6368                                                       path->slots[0]);
6369                                 if (key.objectid == bytenr &&
6370                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
6371                                     key.offset == num_bytes)
6372                                         ret = 0;
6373                         }
6374
6375                         if (ret > 0 && skinny_metadata) {
6376                                 skinny_metadata = false;
6377                                 key.objectid = bytenr;
6378                                 key.type = BTRFS_EXTENT_ITEM_KEY;
6379                                 key.offset = num_bytes;
6380                                 btrfs_release_path(path);
6381                                 ret = btrfs_search_slot(trans, extent_root,
6382                                                         &key, path, -1, 1);
6383                         }
6384
6385                         if (ret) {
6386                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6387                                         ret, bytenr);
6388                                 if (ret > 0)
6389                                         btrfs_print_leaf(extent_root,
6390                                                          path->nodes[0]);
6391                         }
6392                         if (ret < 0) {
6393                                 btrfs_abort_transaction(trans, extent_root, ret);
6394                                 goto out;
6395                         }
6396                         extent_slot = path->slots[0];
6397                 }
6398         } else if (WARN_ON(ret == -ENOENT)) {
6399                 btrfs_print_leaf(extent_root, path->nodes[0]);
6400                 btrfs_err(info,
6401                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
6402                         bytenr, parent, root_objectid, owner_objectid,
6403                         owner_offset);
6404                 btrfs_abort_transaction(trans, extent_root, ret);
6405                 goto out;
6406         } else {
6407                 btrfs_abort_transaction(trans, extent_root, ret);
6408                 goto out;
6409         }
6410
6411         leaf = path->nodes[0];
6412         item_size = btrfs_item_size_nr(leaf, extent_slot);
6413 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
6414         if (item_size < sizeof(*ei)) {
6415                 BUG_ON(found_extent || extent_slot != path->slots[0]);
6416                 ret = convert_extent_item_v0(trans, extent_root, path,
6417                                              owner_objectid, 0);
6418                 if (ret < 0) {
6419                         btrfs_abort_transaction(trans, extent_root, ret);
6420                         goto out;
6421                 }
6422
6423                 btrfs_release_path(path);
6424                 path->leave_spinning = 1;
6425
6426                 key.objectid = bytenr;
6427                 key.type = BTRFS_EXTENT_ITEM_KEY;
6428                 key.offset = num_bytes;
6429
6430                 ret = btrfs_search_slot(trans, extent_root, &key, path,
6431                                         -1, 1);
6432                 if (ret) {
6433                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
6434                                 ret, bytenr);
6435                         btrfs_print_leaf(extent_root, path->nodes[0]);
6436                 }
6437                 if (ret < 0) {
6438                         btrfs_abort_transaction(trans, extent_root, ret);
6439                         goto out;
6440                 }
6441
6442                 extent_slot = path->slots[0];
6443                 leaf = path->nodes[0];
6444                 item_size = btrfs_item_size_nr(leaf, extent_slot);
6445         }
6446 #endif
6447         BUG_ON(item_size < sizeof(*ei));
6448         ei = btrfs_item_ptr(leaf, extent_slot,
6449                             struct btrfs_extent_item);
6450         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
6451             key.type == BTRFS_EXTENT_ITEM_KEY) {
6452                 struct btrfs_tree_block_info *bi;
6453                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
6454                 bi = (struct btrfs_tree_block_info *)(ei + 1);
6455                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
6456         }
6457
6458         refs = btrfs_extent_refs(leaf, ei);
6459         if (refs < refs_to_drop) {
6460                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
6461                           "for bytenr %Lu", refs_to_drop, refs, bytenr);
6462                 ret = -EINVAL;
6463                 btrfs_abort_transaction(trans, extent_root, ret);
6464                 goto out;
6465         }
6466         refs -= refs_to_drop;
6467
6468         if (refs > 0) {
6469                 if (extent_op)
6470                         __run_delayed_extent_op(extent_op, leaf, ei);
6471                 /*
6472                  * In the case of inline back ref, reference count will
6473                  * be updated by remove_extent_backref
6474                  */
6475                 if (iref) {
6476                         BUG_ON(!found_extent);
6477                 } else {
6478                         btrfs_set_extent_refs(leaf, ei, refs);
6479                         btrfs_mark_buffer_dirty(leaf);
6480                 }
6481                 if (found_extent) {
6482                         ret = remove_extent_backref(trans, extent_root, path,
6483                                                     iref, refs_to_drop,
6484                                                     is_data, &last_ref);
6485                         if (ret) {
6486                                 btrfs_abort_transaction(trans, extent_root, ret);
6487                                 goto out;
6488                         }
6489                 }
6490                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
6491                                  root_objectid);
6492         } else {
6493                 if (found_extent) {
6494                         BUG_ON(is_data && refs_to_drop !=
6495                                extent_data_ref_count(path, iref));
6496                         if (iref) {
6497                                 BUG_ON(path->slots[0] != extent_slot);
6498                         } else {
6499                                 BUG_ON(path->slots[0] != extent_slot + 1);
6500                                 path->slots[0] = extent_slot;
6501                                 num_to_del = 2;
6502                         }
6503                 }
6504
6505                 last_ref = 1;
6506                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
6507                                       num_to_del);
6508                 if (ret) {
6509                         btrfs_abort_transaction(trans, extent_root, ret);
6510                         goto out;
6511                 }
6512                 btrfs_release_path(path);
6513
6514                 if (is_data) {
6515                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
6516                         if (ret) {
6517                                 btrfs_abort_transaction(trans, extent_root, ret);
6518                                 goto out;
6519                         }
6520                 }
6521
6522                 ret = update_block_group(trans, root, bytenr, num_bytes, 0);
6523                 if (ret) {
6524                         btrfs_abort_transaction(trans, extent_root, ret);
6525                         goto out;
6526                 }
6527         }
6528         btrfs_release_path(path);
6529
6530 out:
6531         btrfs_free_path(path);
6532         return ret;
6533 }
6534
6535 /*
6536  * when we free an block, it is possible (and likely) that we free the last
6537  * delayed ref for that extent as well.  This searches the delayed ref tree for
6538  * a given extent, and if there are no other delayed refs to be processed, it
6539  * removes it from the tree.
6540  */
6541 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
6542                                       struct btrfs_root *root, u64 bytenr)
6543 {
6544         struct btrfs_delayed_ref_head *head;
6545         struct btrfs_delayed_ref_root *delayed_refs;
6546         int ret = 0;
6547
6548         delayed_refs = &trans->transaction->delayed_refs;
6549         spin_lock(&delayed_refs->lock);
6550         head = btrfs_find_delayed_ref_head(trans, bytenr);
6551         if (!head)
6552                 goto out_delayed_unlock;
6553
6554         spin_lock(&head->lock);
6555         if (!list_empty(&head->ref_list))
6556                 goto out;
6557
6558         if (head->extent_op) {
6559                 if (!head->must_insert_reserved)
6560                         goto out;
6561                 btrfs_free_delayed_extent_op(head->extent_op);
6562                 head->extent_op = NULL;
6563         }
6564
6565         /*
6566          * waiting for the lock here would deadlock.  If someone else has it
6567          * locked they are already in the process of dropping it anyway
6568          */
6569         if (!mutex_trylock(&head->mutex))
6570                 goto out;
6571
6572         /*
6573          * at this point we have a head with no other entries.  Go
6574          * ahead and process it.
6575          */
6576         head->node.in_tree = 0;
6577         rb_erase(&head->href_node, &delayed_refs->href_root);
6578
6579         atomic_dec(&delayed_refs->num_entries);
6580
6581         /*
6582          * we don't take a ref on the node because we're removing it from the
6583          * tree, so we just steal the ref the tree was holding.
6584          */
6585         delayed_refs->num_heads--;
6586         if (head->processing == 0)
6587                 delayed_refs->num_heads_ready--;
6588         head->processing = 0;
6589         spin_unlock(&head->lock);
6590         spin_unlock(&delayed_refs->lock);
6591
6592         BUG_ON(head->extent_op);
6593         if (head->must_insert_reserved)
6594                 ret = 1;
6595
6596         mutex_unlock(&head->mutex);
6597         btrfs_put_delayed_ref(&head->node);
6598         return ret;
6599 out:
6600         spin_unlock(&head->lock);
6601
6602 out_delayed_unlock:
6603         spin_unlock(&delayed_refs->lock);
6604         return 0;
6605 }
6606
6607 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
6608                            struct btrfs_root *root,
6609                            struct extent_buffer *buf,
6610                            u64 parent, int last_ref)
6611 {
6612         int pin = 1;
6613         int ret;
6614
6615         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6616                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
6617                                         buf->start, buf->len,
6618                                         parent, root->root_key.objectid,
6619                                         btrfs_header_level(buf),
6620                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
6621                 BUG_ON(ret); /* -ENOMEM */
6622         }
6623
6624         if (!last_ref)
6625                 return;
6626
6627         if (btrfs_header_generation(buf) == trans->transid) {
6628                 struct btrfs_block_group_cache *cache;
6629
6630                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6631                         ret = check_ref_cleanup(trans, root, buf->start);
6632                         if (!ret)
6633                                 goto out;
6634                 }
6635
6636                 cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6637
6638                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6639                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6640                         btrfs_put_block_group(cache);
6641                         goto out;
6642                 }
6643
6644                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6645
6646                 btrfs_add_free_space(cache, buf->start, buf->len);
6647                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE, 0);
6648                 btrfs_put_block_group(cache);
6649                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6650                 pin = 0;
6651         }
6652 out:
6653         if (pin)
6654                 add_pinned_bytes(root->fs_info, buf->len,
6655                                  btrfs_header_level(buf),
6656                                  root->root_key.objectid);
6657
6658         /*
6659          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6660          * anymore.
6661          */
6662         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6663 }
6664
6665 /* Can return -ENOMEM */
6666 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6667                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6668                       u64 owner, u64 offset, int no_quota)
6669 {
6670         int ret;
6671         struct btrfs_fs_info *fs_info = root->fs_info;
6672
6673         if (btrfs_test_is_dummy_root(root))
6674                 return 0;
6675
6676         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6677
6678         /*
6679          * tree log blocks never actually go into the extent allocation
6680          * tree, just update pinning info and exit early.
6681          */
6682         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6683                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6684                 /* unlocks the pinned mutex */
6685                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6686                 ret = 0;
6687         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6688                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6689                                         num_bytes,
6690                                         parent, root_objectid, (int)owner,
6691                                         BTRFS_DROP_DELAYED_REF, NULL, no_quota);
6692         } else {
6693                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6694                                                 num_bytes,
6695                                                 parent, root_objectid, owner,
6696                                                 offset, BTRFS_DROP_DELAYED_REF,
6697                                                 NULL, no_quota);
6698         }
6699         return ret;
6700 }
6701
6702 /*
6703  * when we wait for progress in the block group caching, its because
6704  * our allocation attempt failed at least once.  So, we must sleep
6705  * and let some progress happen before we try again.
6706  *
6707  * This function will sleep at least once waiting for new free space to
6708  * show up, and then it will check the block group free space numbers
6709  * for our min num_bytes.  Another option is to have it go ahead
6710  * and look in the rbtree for a free extent of a given size, but this
6711  * is a good start.
6712  *
6713  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6714  * any of the information in this block group.
6715  */
6716 static noinline void
6717 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6718                                 u64 num_bytes)
6719 {
6720         struct btrfs_caching_control *caching_ctl;
6721
6722         caching_ctl = get_caching_control(cache);
6723         if (!caching_ctl)
6724                 return;
6725
6726         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6727                    (cache->free_space_ctl->free_space >= num_bytes));
6728
6729         put_caching_control(caching_ctl);
6730 }
6731
6732 static noinline int
6733 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6734 {
6735         struct btrfs_caching_control *caching_ctl;
6736         int ret = 0;
6737
6738         caching_ctl = get_caching_control(cache);
6739         if (!caching_ctl)
6740                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6741
6742         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6743         if (cache->cached == BTRFS_CACHE_ERROR)
6744                 ret = -EIO;
6745         put_caching_control(caching_ctl);
6746         return ret;
6747 }
6748
6749 int __get_raid_index(u64 flags)
6750 {
6751         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6752                 return BTRFS_RAID_RAID10;
6753         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6754                 return BTRFS_RAID_RAID1;
6755         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6756                 return BTRFS_RAID_DUP;
6757         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6758                 return BTRFS_RAID_RAID0;
6759         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6760                 return BTRFS_RAID_RAID5;
6761         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6762                 return BTRFS_RAID_RAID6;
6763
6764         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6765 }
6766
6767 int get_block_group_index(struct btrfs_block_group_cache *cache)
6768 {
6769         return __get_raid_index(cache->flags);
6770 }
6771
6772 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
6773         [BTRFS_RAID_RAID10]     = "raid10",
6774         [BTRFS_RAID_RAID1]      = "raid1",
6775         [BTRFS_RAID_DUP]        = "dup",
6776         [BTRFS_RAID_RAID0]      = "raid0",
6777         [BTRFS_RAID_SINGLE]     = "single",
6778         [BTRFS_RAID_RAID5]      = "raid5",
6779         [BTRFS_RAID_RAID6]      = "raid6",
6780 };
6781
6782 static const char *get_raid_name(enum btrfs_raid_types type)
6783 {
6784         if (type >= BTRFS_NR_RAID_TYPES)
6785                 return NULL;
6786
6787         return btrfs_raid_type_names[type];
6788 }
6789
6790 enum btrfs_loop_type {
6791         LOOP_CACHING_NOWAIT = 0,
6792         LOOP_CACHING_WAIT = 1,
6793         LOOP_ALLOC_CHUNK = 2,
6794         LOOP_NO_EMPTY_SIZE = 3,
6795 };
6796
6797 static inline void
6798 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
6799                        int delalloc)
6800 {
6801         if (delalloc)
6802                 down_read(&cache->data_rwsem);
6803 }
6804
6805 static inline void
6806 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
6807                        int delalloc)
6808 {
6809         btrfs_get_block_group(cache);
6810         if (delalloc)
6811                 down_read(&cache->data_rwsem);
6812 }
6813
6814 static struct btrfs_block_group_cache *
6815 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
6816                    struct btrfs_free_cluster *cluster,
6817                    int delalloc)
6818 {
6819         struct btrfs_block_group_cache *used_bg;
6820         bool locked = false;
6821 again:
6822         spin_lock(&cluster->refill_lock);
6823         if (locked) {
6824                 if (used_bg == cluster->block_group)
6825                         return used_bg;
6826
6827                 up_read(&used_bg->data_rwsem);
6828                 btrfs_put_block_group(used_bg);
6829         }
6830
6831         used_bg = cluster->block_group;
6832         if (!used_bg)
6833                 return NULL;
6834
6835         if (used_bg == block_group)
6836                 return used_bg;
6837
6838         btrfs_get_block_group(used_bg);
6839
6840         if (!delalloc)
6841                 return used_bg;
6842
6843         if (down_read_trylock(&used_bg->data_rwsem))
6844                 return used_bg;
6845
6846         spin_unlock(&cluster->refill_lock);
6847         down_read(&used_bg->data_rwsem);
6848         locked = true;
6849         goto again;
6850 }
6851
6852 static inline void
6853 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
6854                          int delalloc)
6855 {
6856         if (delalloc)
6857                 up_read(&cache->data_rwsem);
6858         btrfs_put_block_group(cache);
6859 }
6860
6861 /*
6862  * walks the btree of allocated extents and find a hole of a given size.
6863  * The key ins is changed to record the hole:
6864  * ins->objectid == start position
6865  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6866  * ins->offset == the size of the hole.
6867  * Any available blocks before search_start are skipped.
6868  *
6869  * If there is no suitable free space, we will record the max size of
6870  * the free space extent currently.
6871  */
6872 static noinline int find_free_extent(struct btrfs_root *orig_root,
6873                                      u64 num_bytes, u64 empty_size,
6874                                      u64 hint_byte, struct btrfs_key *ins,
6875                                      u64 flags, int delalloc)
6876 {
6877         int ret = 0;
6878         struct btrfs_root *root = orig_root->fs_info->extent_root;
6879         struct btrfs_free_cluster *last_ptr = NULL;
6880         struct btrfs_block_group_cache *block_group = NULL;
6881         u64 search_start = 0;
6882         u64 max_extent_size = 0;
6883         int empty_cluster = 2 * 1024 * 1024;
6884         struct btrfs_space_info *space_info;
6885         int loop = 0;
6886         int index = __get_raid_index(flags);
6887         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6888                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6889         bool failed_cluster_refill = false;
6890         bool failed_alloc = false;
6891         bool use_cluster = true;
6892         bool have_caching_bg = false;
6893
6894         WARN_ON(num_bytes < root->sectorsize);
6895         ins->type = BTRFS_EXTENT_ITEM_KEY;
6896         ins->objectid = 0;
6897         ins->offset = 0;
6898
6899         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6900
6901         space_info = __find_space_info(root->fs_info, flags);
6902         if (!space_info) {
6903                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6904                 return -ENOSPC;
6905         }
6906
6907         /*
6908          * If the space info is for both data and metadata it means we have a
6909          * small filesystem and we can't use the clustering stuff.
6910          */
6911         if (btrfs_mixed_space_info(space_info))
6912                 use_cluster = false;
6913
6914         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6915                 last_ptr = &root->fs_info->meta_alloc_cluster;
6916                 if (!btrfs_test_opt(root, SSD))
6917                         empty_cluster = 64 * 1024;
6918         }
6919
6920         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6921             btrfs_test_opt(root, SSD)) {
6922                 last_ptr = &root->fs_info->data_alloc_cluster;
6923         }
6924
6925         if (last_ptr) {
6926                 spin_lock(&last_ptr->lock);
6927                 if (last_ptr->block_group)
6928                         hint_byte = last_ptr->window_start;
6929                 spin_unlock(&last_ptr->lock);
6930         }
6931
6932         search_start = max(search_start, first_logical_byte(root, 0));
6933         search_start = max(search_start, hint_byte);
6934
6935         if (!last_ptr)
6936                 empty_cluster = 0;
6937
6938         if (search_start == hint_byte) {
6939                 block_group = btrfs_lookup_block_group(root->fs_info,
6940                                                        search_start);
6941                 /*
6942                  * we don't want to use the block group if it doesn't match our
6943                  * allocation bits, or if its not cached.
6944                  *
6945                  * However if we are re-searching with an ideal block group
6946                  * picked out then we don't care that the block group is cached.
6947                  */
6948                 if (block_group && block_group_bits(block_group, flags) &&
6949                     block_group->cached != BTRFS_CACHE_NO) {
6950                         down_read(&space_info->groups_sem);
6951                         if (list_empty(&block_group->list) ||
6952                             block_group->ro) {
6953                                 /*
6954                                  * someone is removing this block group,
6955                                  * we can't jump into the have_block_group
6956                                  * target because our list pointers are not
6957                                  * valid
6958                                  */
6959                                 btrfs_put_block_group(block_group);
6960                                 up_read(&space_info->groups_sem);
6961                         } else {
6962                                 index = get_block_group_index(block_group);
6963                                 btrfs_lock_block_group(block_group, delalloc);
6964                                 goto have_block_group;
6965                         }
6966                 } else if (block_group) {
6967                         btrfs_put_block_group(block_group);
6968                 }
6969         }
6970 search:
6971         have_caching_bg = false;
6972         down_read(&space_info->groups_sem);
6973         list_for_each_entry(block_group, &space_info->block_groups[index],
6974                             list) {
6975                 u64 offset;
6976                 int cached;
6977
6978                 btrfs_grab_block_group(block_group, delalloc);
6979                 search_start = block_group->key.objectid;
6980
6981                 /*
6982                  * this can happen if we end up cycling through all the
6983                  * raid types, but we want to make sure we only allocate
6984                  * for the proper type.
6985                  */
6986                 if (!block_group_bits(block_group, flags)) {
6987                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6988                                 BTRFS_BLOCK_GROUP_RAID1 |
6989                                 BTRFS_BLOCK_GROUP_RAID5 |
6990                                 BTRFS_BLOCK_GROUP_RAID6 |
6991                                 BTRFS_BLOCK_GROUP_RAID10;
6992
6993                         /*
6994                          * if they asked for extra copies and this block group
6995                          * doesn't provide them, bail.  This does allow us to
6996                          * fill raid0 from raid1.
6997                          */
6998                         if ((flags & extra) && !(block_group->flags & extra))
6999                                 goto loop;
7000                 }
7001
7002 have_block_group:
7003                 cached = block_group_cache_done(block_group);
7004                 if (unlikely(!cached)) {
7005                         ret = cache_block_group(block_group, 0);
7006                         BUG_ON(ret < 0);
7007                         ret = 0;
7008                 }
7009
7010                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7011                         goto loop;
7012                 if (unlikely(block_group->ro))
7013                         goto loop;
7014
7015                 /*
7016                  * Ok we want to try and use the cluster allocator, so
7017                  * lets look there
7018                  */
7019                 if (last_ptr) {
7020                         struct btrfs_block_group_cache *used_block_group;
7021                         unsigned long aligned_cluster;
7022                         /*
7023                          * the refill lock keeps out other
7024                          * people trying to start a new cluster
7025                          */
7026                         used_block_group = btrfs_lock_cluster(block_group,
7027                                                               last_ptr,
7028                                                               delalloc);
7029                         if (!used_block_group)
7030                                 goto refill_cluster;
7031
7032                         if (used_block_group != block_group &&
7033                             (used_block_group->ro ||
7034                              !block_group_bits(used_block_group, flags)))
7035                                 goto release_cluster;
7036
7037                         offset = btrfs_alloc_from_cluster(used_block_group,
7038                                                 last_ptr,
7039                                                 num_bytes,
7040                                                 used_block_group->key.objectid,
7041                                                 &max_extent_size);
7042                         if (offset) {
7043                                 /* we have a block, we're done */
7044                                 spin_unlock(&last_ptr->refill_lock);
7045                                 trace_btrfs_reserve_extent_cluster(root,
7046                                                 used_block_group,
7047                                                 search_start, num_bytes);
7048                                 if (used_block_group != block_group) {
7049                                         btrfs_release_block_group(block_group,
7050                                                                   delalloc);
7051                                         block_group = used_block_group;
7052                                 }
7053                                 goto checks;
7054                         }
7055
7056                         WARN_ON(last_ptr->block_group != used_block_group);
7057 release_cluster:
7058                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7059                          * set up a new clusters, so lets just skip it
7060                          * and let the allocator find whatever block
7061                          * it can find.  If we reach this point, we
7062                          * will have tried the cluster allocator
7063                          * plenty of times and not have found
7064                          * anything, so we are likely way too
7065                          * fragmented for the clustering stuff to find
7066                          * anything.
7067                          *
7068                          * However, if the cluster is taken from the
7069                          * current block group, release the cluster
7070                          * first, so that we stand a better chance of
7071                          * succeeding in the unclustered
7072                          * allocation.  */
7073                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7074                             used_block_group != block_group) {
7075                                 spin_unlock(&last_ptr->refill_lock);
7076                                 btrfs_release_block_group(used_block_group,
7077                                                           delalloc);
7078                                 goto unclustered_alloc;
7079                         }
7080
7081                         /*
7082                          * this cluster didn't work out, free it and
7083                          * start over
7084                          */
7085                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7086
7087                         if (used_block_group != block_group)
7088                                 btrfs_release_block_group(used_block_group,
7089                                                           delalloc);
7090 refill_cluster:
7091                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7092                                 spin_unlock(&last_ptr->refill_lock);
7093                                 goto unclustered_alloc;
7094                         }
7095
7096                         aligned_cluster = max_t(unsigned long,
7097                                                 empty_cluster + empty_size,
7098                                               block_group->full_stripe_len);
7099
7100                         /* allocate a cluster in this block group */
7101                         ret = btrfs_find_space_cluster(root, block_group,
7102                                                        last_ptr, search_start,
7103                                                        num_bytes,
7104                                                        aligned_cluster);
7105                         if (ret == 0) {
7106                                 /*
7107                                  * now pull our allocation out of this
7108                                  * cluster
7109                                  */
7110                                 offset = btrfs_alloc_from_cluster(block_group,
7111                                                         last_ptr,
7112                                                         num_bytes,
7113                                                         search_start,
7114                                                         &max_extent_size);
7115                                 if (offset) {
7116                                         /* we found one, proceed */
7117                                         spin_unlock(&last_ptr->refill_lock);
7118                                         trace_btrfs_reserve_extent_cluster(root,
7119                                                 block_group, search_start,
7120                                                 num_bytes);
7121                                         goto checks;
7122                                 }
7123                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7124                                    && !failed_cluster_refill) {
7125                                 spin_unlock(&last_ptr->refill_lock);
7126
7127                                 failed_cluster_refill = true;
7128                                 wait_block_group_cache_progress(block_group,
7129                                        num_bytes + empty_cluster + empty_size);
7130                                 goto have_block_group;
7131                         }
7132
7133                         /*
7134                          * at this point we either didn't find a cluster
7135                          * or we weren't able to allocate a block from our
7136                          * cluster.  Free the cluster we've been trying
7137                          * to use, and go to the next block group
7138                          */
7139                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7140                         spin_unlock(&last_ptr->refill_lock);
7141                         goto loop;
7142                 }
7143
7144 unclustered_alloc:
7145                 spin_lock(&block_group->free_space_ctl->tree_lock);
7146                 if (cached &&
7147                     block_group->free_space_ctl->free_space <
7148                     num_bytes + empty_cluster + empty_size) {
7149                         if (block_group->free_space_ctl->free_space >
7150                             max_extent_size)
7151                                 max_extent_size =
7152                                         block_group->free_space_ctl->free_space;
7153                         spin_unlock(&block_group->free_space_ctl->tree_lock);
7154                         goto loop;
7155                 }
7156                 spin_unlock(&block_group->free_space_ctl->tree_lock);
7157
7158                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7159                                                     num_bytes, empty_size,
7160                                                     &max_extent_size);
7161                 /*
7162                  * If we didn't find a chunk, and we haven't failed on this
7163                  * block group before, and this block group is in the middle of
7164                  * caching and we are ok with waiting, then go ahead and wait
7165                  * for progress to be made, and set failed_alloc to true.
7166                  *
7167                  * If failed_alloc is true then we've already waited on this
7168                  * block group once and should move on to the next block group.
7169                  */
7170                 if (!offset && !failed_alloc && !cached &&
7171                     loop > LOOP_CACHING_NOWAIT) {
7172                         wait_block_group_cache_progress(block_group,
7173                                                 num_bytes + empty_size);
7174                         failed_alloc = true;
7175                         goto have_block_group;
7176                 } else if (!offset) {
7177                         if (!cached)
7178                                 have_caching_bg = true;
7179                         goto loop;
7180                 }
7181 checks:
7182                 search_start = ALIGN(offset, root->stripesize);
7183
7184                 /* move on to the next group */
7185                 if (search_start + num_bytes >
7186                     block_group->key.objectid + block_group->key.offset) {
7187                         btrfs_add_free_space(block_group, offset, num_bytes);
7188                         goto loop;
7189                 }
7190
7191                 if (offset < search_start)
7192                         btrfs_add_free_space(block_group, offset,
7193                                              search_start - offset);
7194                 BUG_ON(offset > search_start);
7195
7196                 ret = btrfs_update_reserved_bytes(block_group, num_bytes,
7197                                                   alloc_type, delalloc);
7198                 if (ret == -EAGAIN) {
7199                         btrfs_add_free_space(block_group, offset, num_bytes);
7200                         goto loop;
7201                 }
7202
7203                 /* we are all good, lets return */
7204                 ins->objectid = search_start;
7205                 ins->offset = num_bytes;
7206
7207                 trace_btrfs_reserve_extent(orig_root, block_group,
7208                                            search_start, num_bytes);
7209                 btrfs_release_block_group(block_group, delalloc);
7210                 break;
7211 loop:
7212                 failed_cluster_refill = false;
7213                 failed_alloc = false;
7214                 BUG_ON(index != get_block_group_index(block_group));
7215                 btrfs_release_block_group(block_group, delalloc);
7216         }
7217         up_read(&space_info->groups_sem);
7218
7219         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7220                 goto search;
7221
7222         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7223                 goto search;
7224
7225         /*
7226          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7227          *                      caching kthreads as we move along
7228          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7229          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7230          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7231          *                      again
7232          */
7233         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7234                 index = 0;
7235                 loop++;
7236                 if (loop == LOOP_ALLOC_CHUNK) {
7237                         struct btrfs_trans_handle *trans;
7238                         int exist = 0;
7239
7240                         trans = current->journal_info;
7241                         if (trans)
7242                                 exist = 1;
7243                         else
7244                                 trans = btrfs_join_transaction(root);
7245
7246                         if (IS_ERR(trans)) {
7247                                 ret = PTR_ERR(trans);
7248                                 goto out;
7249                         }
7250
7251                         ret = do_chunk_alloc(trans, root, flags,
7252                                              CHUNK_ALLOC_FORCE);
7253                         /*
7254                          * Do not bail out on ENOSPC since we
7255                          * can do more things.
7256                          */
7257                         if (ret < 0 && ret != -ENOSPC)
7258                                 btrfs_abort_transaction(trans,
7259                                                         root, ret);
7260                         else
7261                                 ret = 0;
7262                         if (!exist)
7263                                 btrfs_end_transaction(trans, root);
7264                         if (ret)
7265                                 goto out;
7266                 }
7267
7268                 if (loop == LOOP_NO_EMPTY_SIZE) {
7269                         empty_size = 0;
7270                         empty_cluster = 0;
7271                 }
7272
7273                 goto search;
7274         } else if (!ins->objectid) {
7275                 ret = -ENOSPC;
7276         } else if (ins->objectid) {
7277                 ret = 0;
7278         }
7279 out:
7280         if (ret == -ENOSPC)
7281                 ins->offset = max_extent_size;
7282         return ret;
7283 }
7284
7285 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
7286                             int dump_block_groups)
7287 {
7288         struct btrfs_block_group_cache *cache;
7289         int index = 0;
7290
7291         spin_lock(&info->lock);
7292         printk(KERN_INFO "BTRFS: space_info %llu has %llu free, is %sfull\n",
7293                info->flags,
7294                info->total_bytes - info->bytes_used - info->bytes_pinned -
7295                info->bytes_reserved - info->bytes_readonly,
7296                (info->full) ? "" : "not ");
7297         printk(KERN_INFO "BTRFS: space_info total=%llu, used=%llu, pinned=%llu, "
7298                "reserved=%llu, may_use=%llu, readonly=%llu\n",
7299                info->total_bytes, info->bytes_used, info->bytes_pinned,
7300                info->bytes_reserved, info->bytes_may_use,
7301                info->bytes_readonly);
7302         spin_unlock(&info->lock);
7303
7304         if (!dump_block_groups)
7305                 return;
7306
7307         down_read(&info->groups_sem);
7308 again:
7309         list_for_each_entry(cache, &info->block_groups[index], list) {
7310                 spin_lock(&cache->lock);
7311                 printk(KERN_INFO "BTRFS: "
7312                            "block group %llu has %llu bytes, "
7313                            "%llu used %llu pinned %llu reserved %s\n",
7314                        cache->key.objectid, cache->key.offset,
7315                        btrfs_block_group_used(&cache->item), cache->pinned,
7316                        cache->reserved, cache->ro ? "[readonly]" : "");
7317                 btrfs_dump_free_space(cache, bytes);
7318                 spin_unlock(&cache->lock);
7319         }
7320         if (++index < BTRFS_NR_RAID_TYPES)
7321                 goto again;
7322         up_read(&info->groups_sem);
7323 }
7324
7325 int btrfs_reserve_extent(struct btrfs_root *root,
7326                          u64 num_bytes, u64 min_alloc_size,
7327                          u64 empty_size, u64 hint_byte,
7328                          struct btrfs_key *ins, int is_data, int delalloc)
7329 {
7330         bool final_tried = false;
7331         u64 flags;
7332         int ret;
7333
7334         flags = btrfs_get_alloc_profile(root, is_data);
7335 again:
7336         WARN_ON(num_bytes < root->sectorsize);
7337         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
7338                                flags, delalloc);
7339
7340         if (ret == -ENOSPC) {
7341                 if (!final_tried && ins->offset) {
7342                         num_bytes = min(num_bytes >> 1, ins->offset);
7343                         num_bytes = round_down(num_bytes, root->sectorsize);
7344                         num_bytes = max(num_bytes, min_alloc_size);
7345                         if (num_bytes == min_alloc_size)
7346                                 final_tried = true;
7347                         goto again;
7348                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7349                         struct btrfs_space_info *sinfo;
7350
7351                         sinfo = __find_space_info(root->fs_info, flags);
7352                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
7353                                 flags, num_bytes);
7354                         if (sinfo)
7355                                 dump_space_info(sinfo, num_bytes, 1);
7356                 }
7357         }
7358
7359         return ret;
7360 }
7361
7362 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
7363                                         u64 start, u64 len,
7364                                         int pin, int delalloc)
7365 {
7366         struct btrfs_block_group_cache *cache;
7367         int ret = 0;
7368
7369         cache = btrfs_lookup_block_group(root->fs_info, start);
7370         if (!cache) {
7371                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
7372                         start);
7373                 return -ENOSPC;
7374         }
7375
7376         if (pin)
7377                 pin_down_extent(root, cache, start, len, 1);
7378         else {
7379                 if (btrfs_test_opt(root, DISCARD))
7380                         ret = btrfs_discard_extent(root, start, len, NULL);
7381                 btrfs_add_free_space(cache, start, len);
7382                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE, delalloc);
7383         }
7384
7385         btrfs_put_block_group(cache);
7386
7387         trace_btrfs_reserved_extent_free(root, start, len);
7388
7389         return ret;
7390 }
7391
7392 int btrfs_free_reserved_extent(struct btrfs_root *root,
7393                                u64 start, u64 len, int delalloc)
7394 {
7395         return __btrfs_free_reserved_extent(root, start, len, 0, delalloc);
7396 }
7397
7398 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
7399                                        u64 start, u64 len)
7400 {
7401         return __btrfs_free_reserved_extent(root, start, len, 1, 0);
7402 }
7403
7404 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7405                                       struct btrfs_root *root,
7406                                       u64 parent, u64 root_objectid,
7407                                       u64 flags, u64 owner, u64 offset,
7408                                       struct btrfs_key *ins, int ref_mod)
7409 {
7410         int ret;
7411         struct btrfs_fs_info *fs_info = root->fs_info;
7412         struct btrfs_extent_item *extent_item;
7413         struct btrfs_extent_inline_ref *iref;
7414         struct btrfs_path *path;
7415         struct extent_buffer *leaf;
7416         int type;
7417         u32 size;
7418
7419         if (parent > 0)
7420                 type = BTRFS_SHARED_DATA_REF_KEY;
7421         else
7422                 type = BTRFS_EXTENT_DATA_REF_KEY;
7423
7424         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
7425
7426         path = btrfs_alloc_path();
7427         if (!path)
7428                 return -ENOMEM;
7429
7430         path->leave_spinning = 1;
7431         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7432                                       ins, size);
7433         if (ret) {
7434                 btrfs_free_path(path);
7435                 return ret;
7436         }
7437
7438         leaf = path->nodes[0];
7439         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7440                                      struct btrfs_extent_item);
7441         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
7442         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7443         btrfs_set_extent_flags(leaf, extent_item,
7444                                flags | BTRFS_EXTENT_FLAG_DATA);
7445
7446         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7447         btrfs_set_extent_inline_ref_type(leaf, iref, type);
7448         if (parent > 0) {
7449                 struct btrfs_shared_data_ref *ref;
7450                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
7451                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7452                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
7453         } else {
7454                 struct btrfs_extent_data_ref *ref;
7455                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
7456                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
7457                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
7458                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
7459                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
7460         }
7461
7462         btrfs_mark_buffer_dirty(path->nodes[0]);
7463         btrfs_free_path(path);
7464
7465         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1);
7466         if (ret) { /* -ENOENT, logic error */
7467                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7468                         ins->objectid, ins->offset);
7469                 BUG();
7470         }
7471         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
7472         return ret;
7473 }
7474
7475 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
7476                                      struct btrfs_root *root,
7477                                      u64 parent, u64 root_objectid,
7478                                      u64 flags, struct btrfs_disk_key *key,
7479                                      int level, struct btrfs_key *ins,
7480                                      int no_quota)
7481 {
7482         int ret;
7483         struct btrfs_fs_info *fs_info = root->fs_info;
7484         struct btrfs_extent_item *extent_item;
7485         struct btrfs_tree_block_info *block_info;
7486         struct btrfs_extent_inline_ref *iref;
7487         struct btrfs_path *path;
7488         struct extent_buffer *leaf;
7489         u32 size = sizeof(*extent_item) + sizeof(*iref);
7490         u64 num_bytes = ins->offset;
7491         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7492                                                  SKINNY_METADATA);
7493
7494         if (!skinny_metadata)
7495                 size += sizeof(*block_info);
7496
7497         path = btrfs_alloc_path();
7498         if (!path) {
7499                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7500                                                    root->nodesize);
7501                 return -ENOMEM;
7502         }
7503
7504         path->leave_spinning = 1;
7505         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
7506                                       ins, size);
7507         if (ret) {
7508                 btrfs_free_path(path);
7509                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
7510                                                    root->nodesize);
7511                 return ret;
7512         }
7513
7514         leaf = path->nodes[0];
7515         extent_item = btrfs_item_ptr(leaf, path->slots[0],
7516                                      struct btrfs_extent_item);
7517         btrfs_set_extent_refs(leaf, extent_item, 1);
7518         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
7519         btrfs_set_extent_flags(leaf, extent_item,
7520                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
7521
7522         if (skinny_metadata) {
7523                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
7524                 num_bytes = root->nodesize;
7525         } else {
7526                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
7527                 btrfs_set_tree_block_key(leaf, block_info, key);
7528                 btrfs_set_tree_block_level(leaf, block_info, level);
7529                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
7530         }
7531
7532         if (parent > 0) {
7533                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
7534                 btrfs_set_extent_inline_ref_type(leaf, iref,
7535                                                  BTRFS_SHARED_BLOCK_REF_KEY);
7536                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
7537         } else {
7538                 btrfs_set_extent_inline_ref_type(leaf, iref,
7539                                                  BTRFS_TREE_BLOCK_REF_KEY);
7540                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
7541         }
7542
7543         btrfs_mark_buffer_dirty(leaf);
7544         btrfs_free_path(path);
7545
7546         ret = update_block_group(trans, root, ins->objectid, root->nodesize,
7547                                  1);
7548         if (ret) { /* -ENOENT, logic error */
7549                 btrfs_err(fs_info, "update block group failed for %llu %llu",
7550                         ins->objectid, ins->offset);
7551                 BUG();
7552         }
7553
7554         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->nodesize);
7555         return ret;
7556 }
7557
7558 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
7559                                      struct btrfs_root *root,
7560                                      u64 root_objectid, u64 owner,
7561                                      u64 offset, struct btrfs_key *ins)
7562 {
7563         int ret;
7564
7565         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
7566
7567         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
7568                                          ins->offset, 0,
7569                                          root_objectid, owner, offset,
7570                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
7571         return ret;
7572 }
7573
7574 /*
7575  * this is used by the tree logging recovery code.  It records that
7576  * an extent has been allocated and makes sure to clear the free
7577  * space cache bits as well
7578  */
7579 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
7580                                    struct btrfs_root *root,
7581                                    u64 root_objectid, u64 owner, u64 offset,
7582                                    struct btrfs_key *ins)
7583 {
7584         int ret;
7585         struct btrfs_block_group_cache *block_group;
7586
7587         /*
7588          * Mixed block groups will exclude before processing the log so we only
7589          * need to do the exlude dance if this fs isn't mixed.
7590          */
7591         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
7592                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
7593                 if (ret)
7594                         return ret;
7595         }
7596
7597         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
7598         if (!block_group)
7599                 return -EINVAL;
7600
7601         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
7602                                           RESERVE_ALLOC_NO_ACCOUNT, 0);
7603         BUG_ON(ret); /* logic error */
7604         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
7605                                          0, owner, offset, ins, 1);
7606         btrfs_put_block_group(block_group);
7607         return ret;
7608 }
7609
7610 static struct extent_buffer *
7611 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
7612                       u64 bytenr, int level)
7613 {
7614         struct extent_buffer *buf;
7615
7616         buf = btrfs_find_create_tree_block(root, bytenr);
7617         if (!buf)
7618                 return ERR_PTR(-ENOMEM);
7619         btrfs_set_header_generation(buf, trans->transid);
7620         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
7621         btrfs_tree_lock(buf);
7622         clean_tree_block(trans, root->fs_info, buf);
7623         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
7624
7625         btrfs_set_lock_blocking(buf);
7626         btrfs_set_buffer_uptodate(buf);
7627
7628         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
7629                 buf->log_index = root->log_transid % 2;
7630                 /*
7631                  * we allow two log transactions at a time, use different
7632                  * EXENT bit to differentiate dirty pages.
7633                  */
7634                 if (buf->log_index == 0)
7635                         set_extent_dirty(&root->dirty_log_pages, buf->start,
7636                                         buf->start + buf->len - 1, GFP_NOFS);
7637                 else
7638                         set_extent_new(&root->dirty_log_pages, buf->start,
7639                                         buf->start + buf->len - 1, GFP_NOFS);
7640         } else {
7641                 buf->log_index = -1;
7642                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
7643                          buf->start + buf->len - 1, GFP_NOFS);
7644         }
7645         trans->blocks_used++;
7646         /* this returns a buffer locked for blocking */
7647         return buf;
7648 }
7649
7650 static struct btrfs_block_rsv *
7651 use_block_rsv(struct btrfs_trans_handle *trans,
7652               struct btrfs_root *root, u32 blocksize)
7653 {
7654         struct btrfs_block_rsv *block_rsv;
7655         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
7656         int ret;
7657         bool global_updated = false;
7658
7659         block_rsv = get_block_rsv(trans, root);
7660
7661         if (unlikely(block_rsv->size == 0))
7662                 goto try_reserve;
7663 again:
7664         ret = block_rsv_use_bytes(block_rsv, blocksize);
7665         if (!ret)
7666                 return block_rsv;
7667
7668         if (block_rsv->failfast)
7669                 return ERR_PTR(ret);
7670
7671         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
7672                 global_updated = true;
7673                 update_global_block_rsv(root->fs_info);
7674                 goto again;
7675         }
7676
7677         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
7678                 static DEFINE_RATELIMIT_STATE(_rs,
7679                                 DEFAULT_RATELIMIT_INTERVAL * 10,
7680                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
7681                 if (__ratelimit(&_rs))
7682                         WARN(1, KERN_DEBUG
7683                                 "BTRFS: block rsv returned %d\n", ret);
7684         }
7685 try_reserve:
7686         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
7687                                      BTRFS_RESERVE_NO_FLUSH);
7688         if (!ret)
7689                 return block_rsv;
7690         /*
7691          * If we couldn't reserve metadata bytes try and use some from
7692          * the global reserve if its space type is the same as the global
7693          * reservation.
7694          */
7695         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
7696             block_rsv->space_info == global_rsv->space_info) {
7697                 ret = block_rsv_use_bytes(global_rsv, blocksize);
7698                 if (!ret)
7699                         return global_rsv;
7700         }
7701         return ERR_PTR(ret);
7702 }
7703
7704 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
7705                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
7706 {
7707         block_rsv_add_bytes(block_rsv, blocksize, 0);
7708         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
7709 }
7710
7711 /*
7712  * finds a free extent and does all the dirty work required for allocation
7713  * returns the tree buffer or an ERR_PTR on error.
7714  */
7715 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
7716                                         struct btrfs_root *root,
7717                                         u64 parent, u64 root_objectid,
7718                                         struct btrfs_disk_key *key, int level,
7719                                         u64 hint, u64 empty_size)
7720 {
7721         struct btrfs_key ins;
7722         struct btrfs_block_rsv *block_rsv;
7723         struct extent_buffer *buf;
7724         struct btrfs_delayed_extent_op *extent_op;
7725         u64 flags = 0;
7726         int ret;
7727         u32 blocksize = root->nodesize;
7728         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7729                                                  SKINNY_METADATA);
7730
7731         if (btrfs_test_is_dummy_root(root)) {
7732                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
7733                                             level);
7734                 if (!IS_ERR(buf))
7735                         root->alloc_bytenr += blocksize;
7736                 return buf;
7737         }
7738
7739         block_rsv = use_block_rsv(trans, root, blocksize);
7740         if (IS_ERR(block_rsv))
7741                 return ERR_CAST(block_rsv);
7742
7743         ret = btrfs_reserve_extent(root, blocksize, blocksize,
7744                                    empty_size, hint, &ins, 0, 0);
7745         if (ret)
7746                 goto out_unuse;
7747
7748         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
7749         if (IS_ERR(buf)) {
7750                 ret = PTR_ERR(buf);
7751                 goto out_free_reserved;
7752         }
7753
7754         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
7755                 if (parent == 0)
7756                         parent = ins.objectid;
7757                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
7758         } else
7759                 BUG_ON(parent > 0);
7760
7761         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
7762                 extent_op = btrfs_alloc_delayed_extent_op();
7763                 if (!extent_op) {
7764                         ret = -ENOMEM;
7765                         goto out_free_buf;
7766                 }
7767                 if (key)
7768                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
7769                 else
7770                         memset(&extent_op->key, 0, sizeof(extent_op->key));
7771                 extent_op->flags_to_set = flags;
7772                 if (skinny_metadata)
7773                         extent_op->update_key = 0;
7774                 else
7775                         extent_op->update_key = 1;
7776                 extent_op->update_flags = 1;
7777                 extent_op->is_data = 0;
7778                 extent_op->level = level;
7779
7780                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7781                                                  ins.objectid, ins.offset,
7782                                                  parent, root_objectid, level,
7783                                                  BTRFS_ADD_DELAYED_EXTENT,
7784                                                  extent_op, 0);
7785                 if (ret)
7786                         goto out_free_delayed;
7787         }
7788         return buf;
7789
7790 out_free_delayed:
7791         btrfs_free_delayed_extent_op(extent_op);
7792 out_free_buf:
7793         free_extent_buffer(buf);
7794 out_free_reserved:
7795         btrfs_free_reserved_extent(root, ins.objectid, ins.offset, 0);
7796 out_unuse:
7797         unuse_block_rsv(root->fs_info, block_rsv, blocksize);
7798         return ERR_PTR(ret);
7799 }
7800
7801 struct walk_control {
7802         u64 refs[BTRFS_MAX_LEVEL];
7803         u64 flags[BTRFS_MAX_LEVEL];
7804         struct btrfs_key update_progress;
7805         int stage;
7806         int level;
7807         int shared_level;
7808         int update_ref;
7809         int keep_locks;
7810         int reada_slot;
7811         int reada_count;
7812         int for_reloc;
7813 };
7814
7815 #define DROP_REFERENCE  1
7816 #define UPDATE_BACKREF  2
7817
7818 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7819                                      struct btrfs_root *root,
7820                                      struct walk_control *wc,
7821                                      struct btrfs_path *path)
7822 {
7823         u64 bytenr;
7824         u64 generation;
7825         u64 refs;
7826         u64 flags;
7827         u32 nritems;
7828         u32 blocksize;
7829         struct btrfs_key key;
7830         struct extent_buffer *eb;
7831         int ret;
7832         int slot;
7833         int nread = 0;
7834
7835         if (path->slots[wc->level] < wc->reada_slot) {
7836                 wc->reada_count = wc->reada_count * 2 / 3;
7837                 wc->reada_count = max(wc->reada_count, 2);
7838         } else {
7839                 wc->reada_count = wc->reada_count * 3 / 2;
7840                 wc->reada_count = min_t(int, wc->reada_count,
7841                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7842         }
7843
7844         eb = path->nodes[wc->level];
7845         nritems = btrfs_header_nritems(eb);
7846         blocksize = root->nodesize;
7847
7848         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7849                 if (nread >= wc->reada_count)
7850                         break;
7851
7852                 cond_resched();
7853                 bytenr = btrfs_node_blockptr(eb, slot);
7854                 generation = btrfs_node_ptr_generation(eb, slot);
7855
7856                 if (slot == path->slots[wc->level])
7857                         goto reada;
7858
7859                 if (wc->stage == UPDATE_BACKREF &&
7860                     generation <= root->root_key.offset)
7861                         continue;
7862
7863                 /* We don't lock the tree block, it's OK to be racy here */
7864                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7865                                                wc->level - 1, 1, &refs,
7866                                                &flags);
7867                 /* We don't care about errors in readahead. */
7868                 if (ret < 0)
7869                         continue;
7870                 BUG_ON(refs == 0);
7871
7872                 if (wc->stage == DROP_REFERENCE) {
7873                         if (refs == 1)
7874                                 goto reada;
7875
7876                         if (wc->level == 1 &&
7877                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7878                                 continue;
7879                         if (!wc->update_ref ||
7880                             generation <= root->root_key.offset)
7881                                 continue;
7882                         btrfs_node_key_to_cpu(eb, &key, slot);
7883                         ret = btrfs_comp_cpu_keys(&key,
7884                                                   &wc->update_progress);
7885                         if (ret < 0)
7886                                 continue;
7887                 } else {
7888                         if (wc->level == 1 &&
7889                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7890                                 continue;
7891                 }
7892 reada:
7893                 readahead_tree_block(root, bytenr);
7894                 nread++;
7895         }
7896         wc->reada_slot = slot;
7897 }
7898
7899 /*
7900  * TODO: Modify related function to add related node/leaf to dirty_extent_root,
7901  * for later qgroup accounting.
7902  *
7903  * Current, this function does nothing.
7904  */
7905 static int account_leaf_items(struct btrfs_trans_handle *trans,
7906                               struct btrfs_root *root,
7907                               struct extent_buffer *eb)
7908 {
7909         int nr = btrfs_header_nritems(eb);
7910         int i, extent_type;
7911         struct btrfs_key key;
7912         struct btrfs_file_extent_item *fi;
7913         u64 bytenr, num_bytes;
7914
7915         for (i = 0; i < nr; i++) {
7916                 btrfs_item_key_to_cpu(eb, &key, i);
7917
7918                 if (key.type != BTRFS_EXTENT_DATA_KEY)
7919                         continue;
7920
7921                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
7922                 /* filter out non qgroup-accountable extents  */
7923                 extent_type = btrfs_file_extent_type(eb, fi);
7924
7925                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
7926                         continue;
7927
7928                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
7929                 if (!bytenr)
7930                         continue;
7931
7932                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
7933         }
7934         return 0;
7935 }
7936
7937 /*
7938  * Walk up the tree from the bottom, freeing leaves and any interior
7939  * nodes which have had all slots visited. If a node (leaf or
7940  * interior) is freed, the node above it will have it's slot
7941  * incremented. The root node will never be freed.
7942  *
7943  * At the end of this function, we should have a path which has all
7944  * slots incremented to the next position for a search. If we need to
7945  * read a new node it will be NULL and the node above it will have the
7946  * correct slot selected for a later read.
7947  *
7948  * If we increment the root nodes slot counter past the number of
7949  * elements, 1 is returned to signal completion of the search.
7950  */
7951 static int adjust_slots_upwards(struct btrfs_root *root,
7952                                 struct btrfs_path *path, int root_level)
7953 {
7954         int level = 0;
7955         int nr, slot;
7956         struct extent_buffer *eb;
7957
7958         if (root_level == 0)
7959                 return 1;
7960
7961         while (level <= root_level) {
7962                 eb = path->nodes[level];
7963                 nr = btrfs_header_nritems(eb);
7964                 path->slots[level]++;
7965                 slot = path->slots[level];
7966                 if (slot >= nr || level == 0) {
7967                         /*
7968                          * Don't free the root -  we will detect this
7969                          * condition after our loop and return a
7970                          * positive value for caller to stop walking the tree.
7971                          */
7972                         if (level != root_level) {
7973                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7974                                 path->locks[level] = 0;
7975
7976                                 free_extent_buffer(eb);
7977                                 path->nodes[level] = NULL;
7978                                 path->slots[level] = 0;
7979                         }
7980                 } else {
7981                         /*
7982                          * We have a valid slot to walk back down
7983                          * from. Stop here so caller can process these
7984                          * new nodes.
7985                          */
7986                         break;
7987                 }
7988
7989                 level++;
7990         }
7991
7992         eb = path->nodes[root_level];
7993         if (path->slots[root_level] >= btrfs_header_nritems(eb))
7994                 return 1;
7995
7996         return 0;
7997 }
7998
7999 /*
8000  * root_eb is the subtree root and is locked before this function is called.
8001  * TODO: Modify this function to mark all (including complete shared node)
8002  * to dirty_extent_root to allow it get accounted in qgroup.
8003  */
8004 static int account_shared_subtree(struct btrfs_trans_handle *trans,
8005                                   struct btrfs_root *root,
8006                                   struct extent_buffer *root_eb,
8007                                   u64 root_gen,
8008                                   int root_level)
8009 {
8010         int ret = 0;
8011         int level;
8012         struct extent_buffer *eb = root_eb;
8013         struct btrfs_path *path = NULL;
8014
8015         BUG_ON(root_level < 0 || root_level > BTRFS_MAX_LEVEL);
8016         BUG_ON(root_eb == NULL);
8017
8018         if (!root->fs_info->quota_enabled)
8019                 return 0;
8020
8021         if (!extent_buffer_uptodate(root_eb)) {
8022                 ret = btrfs_read_buffer(root_eb, root_gen);
8023                 if (ret)
8024                         goto out;
8025         }
8026
8027         if (root_level == 0) {
8028                 ret = account_leaf_items(trans, root, root_eb);
8029                 goto out;
8030         }
8031
8032         path = btrfs_alloc_path();
8033         if (!path)
8034                 return -ENOMEM;
8035
8036         /*
8037          * Walk down the tree.  Missing extent blocks are filled in as
8038          * we go. Metadata is accounted every time we read a new
8039          * extent block.
8040          *
8041          * When we reach a leaf, we account for file extent items in it,
8042          * walk back up the tree (adjusting slot pointers as we go)
8043          * and restart the search process.
8044          */
8045         extent_buffer_get(root_eb); /* For path */
8046         path->nodes[root_level] = root_eb;
8047         path->slots[root_level] = 0;
8048         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
8049 walk_down:
8050         level = root_level;
8051         while (level >= 0) {
8052                 if (path->nodes[level] == NULL) {
8053                         int parent_slot;
8054                         u64 child_gen;
8055                         u64 child_bytenr;
8056
8057                         /* We need to get child blockptr/gen from
8058                          * parent before we can read it. */
8059                         eb = path->nodes[level + 1];
8060                         parent_slot = path->slots[level + 1];
8061                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
8062                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
8063
8064                         eb = read_tree_block(root, child_bytenr, child_gen);
8065                         if (IS_ERR(eb)) {
8066                                 ret = PTR_ERR(eb);
8067                                 goto out;
8068                         } else if (!extent_buffer_uptodate(eb)) {
8069                                 free_extent_buffer(eb);
8070                                 ret = -EIO;
8071                                 goto out;
8072                         }
8073
8074                         path->nodes[level] = eb;
8075                         path->slots[level] = 0;
8076
8077                         btrfs_tree_read_lock(eb);
8078                         btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
8079                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
8080                 }
8081
8082                 if (level == 0) {
8083                         ret = account_leaf_items(trans, root, path->nodes[level]);
8084                         if (ret)
8085                                 goto out;
8086
8087                         /* Nonzero return here means we completed our search */
8088                         ret = adjust_slots_upwards(root, path, root_level);
8089                         if (ret)
8090                                 break;
8091
8092                         /* Restart search with new slots */
8093                         goto walk_down;
8094                 }
8095
8096                 level--;
8097         }
8098
8099         ret = 0;
8100 out:
8101         btrfs_free_path(path);
8102
8103         return ret;
8104 }
8105
8106 /*
8107  * helper to process tree block while walking down the tree.
8108  *
8109  * when wc->stage == UPDATE_BACKREF, this function updates
8110  * back refs for pointers in the block.
8111  *
8112  * NOTE: return value 1 means we should stop walking down.
8113  */
8114 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8115                                    struct btrfs_root *root,
8116                                    struct btrfs_path *path,
8117                                    struct walk_control *wc, int lookup_info)
8118 {
8119         int level = wc->level;
8120         struct extent_buffer *eb = path->nodes[level];
8121         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8122         int ret;
8123
8124         if (wc->stage == UPDATE_BACKREF &&
8125             btrfs_header_owner(eb) != root->root_key.objectid)
8126                 return 1;
8127
8128         /*
8129          * when reference count of tree block is 1, it won't increase
8130          * again. once full backref flag is set, we never clear it.
8131          */
8132         if (lookup_info &&
8133             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8134              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8135                 BUG_ON(!path->locks[level]);
8136                 ret = btrfs_lookup_extent_info(trans, root,
8137                                                eb->start, level, 1,
8138                                                &wc->refs[level],
8139                                                &wc->flags[level]);
8140                 BUG_ON(ret == -ENOMEM);
8141                 if (ret)
8142                         return ret;
8143                 BUG_ON(wc->refs[level] == 0);
8144         }
8145
8146         if (wc->stage == DROP_REFERENCE) {
8147                 if (wc->refs[level] > 1)
8148                         return 1;
8149
8150                 if (path->locks[level] && !wc->keep_locks) {
8151                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8152                         path->locks[level] = 0;
8153                 }
8154                 return 0;
8155         }
8156
8157         /* wc->stage == UPDATE_BACKREF */
8158         if (!(wc->flags[level] & flag)) {
8159                 BUG_ON(!path->locks[level]);
8160                 ret = btrfs_inc_ref(trans, root, eb, 1);
8161                 BUG_ON(ret); /* -ENOMEM */
8162                 ret = btrfs_dec_ref(trans, root, eb, 0);
8163                 BUG_ON(ret); /* -ENOMEM */
8164                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
8165                                                   eb->len, flag,
8166                                                   btrfs_header_level(eb), 0);
8167                 BUG_ON(ret); /* -ENOMEM */
8168                 wc->flags[level] |= flag;
8169         }
8170
8171         /*
8172          * the block is shared by multiple trees, so it's not good to
8173          * keep the tree lock
8174          */
8175         if (path->locks[level] && level > 0) {
8176                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8177                 path->locks[level] = 0;
8178         }
8179         return 0;
8180 }
8181
8182 /*
8183  * helper to process tree block pointer.
8184  *
8185  * when wc->stage == DROP_REFERENCE, this function checks
8186  * reference count of the block pointed to. if the block
8187  * is shared and we need update back refs for the subtree
8188  * rooted at the block, this function changes wc->stage to
8189  * UPDATE_BACKREF. if the block is shared and there is no
8190  * need to update back, this function drops the reference
8191  * to the block.
8192  *
8193  * NOTE: return value 1 means we should stop walking down.
8194  */
8195 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8196                                  struct btrfs_root *root,
8197                                  struct btrfs_path *path,
8198                                  struct walk_control *wc, int *lookup_info)
8199 {
8200         u64 bytenr;
8201         u64 generation;
8202         u64 parent;
8203         u32 blocksize;
8204         struct btrfs_key key;
8205         struct extent_buffer *next;
8206         int level = wc->level;
8207         int reada = 0;
8208         int ret = 0;
8209         bool need_account = false;
8210
8211         generation = btrfs_node_ptr_generation(path->nodes[level],
8212                                                path->slots[level]);
8213         /*
8214          * if the lower level block was created before the snapshot
8215          * was created, we know there is no need to update back refs
8216          * for the subtree
8217          */
8218         if (wc->stage == UPDATE_BACKREF &&
8219             generation <= root->root_key.offset) {
8220                 *lookup_info = 1;
8221                 return 1;
8222         }
8223
8224         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8225         blocksize = root->nodesize;
8226
8227         next = btrfs_find_tree_block(root->fs_info, bytenr);
8228         if (!next) {
8229                 next = btrfs_find_create_tree_block(root, bytenr);
8230                 if (!next)
8231                         return -ENOMEM;
8232                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8233                                                level - 1);
8234                 reada = 1;
8235         }
8236         btrfs_tree_lock(next);
8237         btrfs_set_lock_blocking(next);
8238
8239         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
8240                                        &wc->refs[level - 1],
8241                                        &wc->flags[level - 1]);
8242         if (ret < 0) {
8243                 btrfs_tree_unlock(next);
8244                 return ret;
8245         }
8246
8247         if (unlikely(wc->refs[level - 1] == 0)) {
8248                 btrfs_err(root->fs_info, "Missing references.");
8249                 BUG();
8250         }
8251         *lookup_info = 0;
8252
8253         if (wc->stage == DROP_REFERENCE) {
8254                 if (wc->refs[level - 1] > 1) {
8255                         need_account = true;
8256                         if (level == 1 &&
8257                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8258                                 goto skip;
8259
8260                         if (!wc->update_ref ||
8261                             generation <= root->root_key.offset)
8262                                 goto skip;
8263
8264                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8265                                               path->slots[level]);
8266                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8267                         if (ret < 0)
8268                                 goto skip;
8269
8270                         wc->stage = UPDATE_BACKREF;
8271                         wc->shared_level = level - 1;
8272                 }
8273         } else {
8274                 if (level == 1 &&
8275                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8276                         goto skip;
8277         }
8278
8279         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8280                 btrfs_tree_unlock(next);
8281                 free_extent_buffer(next);
8282                 next = NULL;
8283                 *lookup_info = 1;
8284         }
8285
8286         if (!next) {
8287                 if (reada && level == 1)
8288                         reada_walk_down(trans, root, wc, path);
8289                 next = read_tree_block(root, bytenr, generation);
8290                 if (IS_ERR(next)) {
8291                         return PTR_ERR(next);
8292                 } else if (!extent_buffer_uptodate(next)) {
8293                         free_extent_buffer(next);
8294                         return -EIO;
8295                 }
8296                 btrfs_tree_lock(next);
8297                 btrfs_set_lock_blocking(next);
8298         }
8299
8300         level--;
8301         BUG_ON(level != btrfs_header_level(next));
8302         path->nodes[level] = next;
8303         path->slots[level] = 0;
8304         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8305         wc->level = level;
8306         if (wc->level == 1)
8307                 wc->reada_slot = 0;
8308         return 0;
8309 skip:
8310         wc->refs[level - 1] = 0;
8311         wc->flags[level - 1] = 0;
8312         if (wc->stage == DROP_REFERENCE) {
8313                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8314                         parent = path->nodes[level]->start;
8315                 } else {
8316                         BUG_ON(root->root_key.objectid !=
8317                                btrfs_header_owner(path->nodes[level]));
8318                         parent = 0;
8319                 }
8320
8321                 if (need_account) {
8322                         ret = account_shared_subtree(trans, root, next,
8323                                                      generation, level - 1);
8324                         if (ret) {
8325                                 btrfs_err_rl(root->fs_info,
8326                                         "Error "
8327                                         "%d accounting shared subtree. Quota "
8328                                         "is out of sync, rescan required.",
8329                                         ret);
8330                         }
8331                 }
8332                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
8333                                 root->root_key.objectid, level - 1, 0, 0);
8334                 BUG_ON(ret); /* -ENOMEM */
8335         }
8336         btrfs_tree_unlock(next);
8337         free_extent_buffer(next);
8338         *lookup_info = 1;
8339         return 1;
8340 }
8341
8342 /*
8343  * helper to process tree block while walking up the tree.
8344  *
8345  * when wc->stage == DROP_REFERENCE, this function drops
8346  * reference count on the block.
8347  *
8348  * when wc->stage == UPDATE_BACKREF, this function changes
8349  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8350  * to UPDATE_BACKREF previously while processing the block.
8351  *
8352  * NOTE: return value 1 means we should stop walking up.
8353  */
8354 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8355                                  struct btrfs_root *root,
8356                                  struct btrfs_path *path,
8357                                  struct walk_control *wc)
8358 {
8359         int ret;
8360         int level = wc->level;
8361         struct extent_buffer *eb = path->nodes[level];
8362         u64 parent = 0;
8363
8364         if (wc->stage == UPDATE_BACKREF) {
8365                 BUG_ON(wc->shared_level < level);
8366                 if (level < wc->shared_level)
8367                         goto out;
8368
8369                 ret = find_next_key(path, level + 1, &wc->update_progress);
8370                 if (ret > 0)
8371                         wc->update_ref = 0;
8372
8373                 wc->stage = DROP_REFERENCE;
8374                 wc->shared_level = -1;
8375                 path->slots[level] = 0;
8376
8377                 /*
8378                  * check reference count again if the block isn't locked.
8379                  * we should start walking down the tree again if reference
8380                  * count is one.
8381                  */
8382                 if (!path->locks[level]) {
8383                         BUG_ON(level == 0);
8384                         btrfs_tree_lock(eb);
8385                         btrfs_set_lock_blocking(eb);
8386                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8387
8388                         ret = btrfs_lookup_extent_info(trans, root,
8389                                                        eb->start, level, 1,
8390                                                        &wc->refs[level],
8391                                                        &wc->flags[level]);
8392                         if (ret < 0) {
8393                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8394                                 path->locks[level] = 0;
8395                                 return ret;
8396                         }
8397                         BUG_ON(wc->refs[level] == 0);
8398                         if (wc->refs[level] == 1) {
8399                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8400                                 path->locks[level] = 0;
8401                                 return 1;
8402                         }
8403                 }
8404         }
8405
8406         /* wc->stage == DROP_REFERENCE */
8407         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
8408
8409         if (wc->refs[level] == 1) {
8410                 if (level == 0) {
8411                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8412                                 ret = btrfs_dec_ref(trans, root, eb, 1);
8413                         else
8414                                 ret = btrfs_dec_ref(trans, root, eb, 0);
8415                         BUG_ON(ret); /* -ENOMEM */
8416                         ret = account_leaf_items(trans, root, eb);
8417                         if (ret) {
8418                                 btrfs_err_rl(root->fs_info,
8419                                         "error "
8420                                         "%d accounting leaf items. Quota "
8421                                         "is out of sync, rescan required.",
8422                                         ret);
8423                         }
8424                 }
8425                 /* make block locked assertion in clean_tree_block happy */
8426                 if (!path->locks[level] &&
8427                     btrfs_header_generation(eb) == trans->transid) {
8428                         btrfs_tree_lock(eb);
8429                         btrfs_set_lock_blocking(eb);
8430                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8431                 }
8432                 clean_tree_block(trans, root->fs_info, eb);
8433         }
8434
8435         if (eb == root->node) {
8436                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8437                         parent = eb->start;
8438                 else
8439                         BUG_ON(root->root_key.objectid !=
8440                                btrfs_header_owner(eb));
8441         } else {
8442                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
8443                         parent = path->nodes[level + 1]->start;
8444                 else
8445                         BUG_ON(root->root_key.objectid !=
8446                                btrfs_header_owner(path->nodes[level + 1]));
8447         }
8448
8449         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
8450 out:
8451         wc->refs[level] = 0;
8452         wc->flags[level] = 0;
8453         return 0;
8454 }
8455
8456 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
8457                                    struct btrfs_root *root,
8458                                    struct btrfs_path *path,
8459                                    struct walk_control *wc)
8460 {
8461         int level = wc->level;
8462         int lookup_info = 1;
8463         int ret;
8464
8465         while (level >= 0) {
8466                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
8467                 if (ret > 0)
8468                         break;
8469
8470                 if (level == 0)
8471                         break;
8472
8473                 if (path->slots[level] >=
8474                     btrfs_header_nritems(path->nodes[level]))
8475                         break;
8476
8477                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
8478                 if (ret > 0) {
8479                         path->slots[level]++;
8480                         continue;
8481                 } else if (ret < 0)
8482                         return ret;
8483                 level = wc->level;
8484         }
8485         return 0;
8486 }
8487
8488 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
8489                                  struct btrfs_root *root,
8490                                  struct btrfs_path *path,
8491                                  struct walk_control *wc, int max_level)
8492 {
8493         int level = wc->level;
8494         int ret;
8495
8496         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
8497         while (level < max_level && path->nodes[level]) {
8498                 wc->level = level;
8499                 if (path->slots[level] + 1 <
8500                     btrfs_header_nritems(path->nodes[level])) {
8501                         path->slots[level]++;
8502                         return 0;
8503                 } else {
8504                         ret = walk_up_proc(trans, root, path, wc);
8505                         if (ret > 0)
8506                                 return 0;
8507
8508                         if (path->locks[level]) {
8509                                 btrfs_tree_unlock_rw(path->nodes[level],
8510                                                      path->locks[level]);
8511                                 path->locks[level] = 0;
8512                         }
8513                         free_extent_buffer(path->nodes[level]);
8514                         path->nodes[level] = NULL;
8515                         level++;
8516                 }
8517         }
8518         return 1;
8519 }
8520
8521 /*
8522  * drop a subvolume tree.
8523  *
8524  * this function traverses the tree freeing any blocks that only
8525  * referenced by the tree.
8526  *
8527  * when a shared tree block is found. this function decreases its
8528  * reference count by one. if update_ref is true, this function
8529  * also make sure backrefs for the shared block and all lower level
8530  * blocks are properly updated.
8531  *
8532  * If called with for_reloc == 0, may exit early with -EAGAIN
8533  */
8534 int btrfs_drop_snapshot(struct btrfs_root *root,
8535                          struct btrfs_block_rsv *block_rsv, int update_ref,
8536                          int for_reloc)
8537 {
8538         struct btrfs_path *path;
8539         struct btrfs_trans_handle *trans;
8540         struct btrfs_root *tree_root = root->fs_info->tree_root;
8541         struct btrfs_root_item *root_item = &root->root_item;
8542         struct walk_control *wc;
8543         struct btrfs_key key;
8544         int err = 0;
8545         int ret;
8546         int level;
8547         bool root_dropped = false;
8548
8549         btrfs_debug(root->fs_info, "Drop subvolume %llu", root->objectid);
8550
8551         path = btrfs_alloc_path();
8552         if (!path) {
8553                 err = -ENOMEM;
8554                 goto out;
8555         }
8556
8557         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8558         if (!wc) {
8559                 btrfs_free_path(path);
8560                 err = -ENOMEM;
8561                 goto out;
8562         }
8563
8564         trans = btrfs_start_transaction(tree_root, 0);
8565         if (IS_ERR(trans)) {
8566                 err = PTR_ERR(trans);
8567                 goto out_free;
8568         }
8569
8570         if (block_rsv)
8571                 trans->block_rsv = block_rsv;
8572
8573         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
8574                 level = btrfs_header_level(root->node);
8575                 path->nodes[level] = btrfs_lock_root_node(root);
8576                 btrfs_set_lock_blocking(path->nodes[level]);
8577                 path->slots[level] = 0;
8578                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8579                 memset(&wc->update_progress, 0,
8580                        sizeof(wc->update_progress));
8581         } else {
8582                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
8583                 memcpy(&wc->update_progress, &key,
8584                        sizeof(wc->update_progress));
8585
8586                 level = root_item->drop_level;
8587                 BUG_ON(level == 0);
8588                 path->lowest_level = level;
8589                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
8590                 path->lowest_level = 0;
8591                 if (ret < 0) {
8592                         err = ret;
8593                         goto out_end_trans;
8594                 }
8595                 WARN_ON(ret > 0);
8596
8597                 /*
8598                  * unlock our path, this is safe because only this
8599                  * function is allowed to delete this snapshot
8600                  */
8601                 btrfs_unlock_up_safe(path, 0);
8602
8603                 level = btrfs_header_level(root->node);
8604                 while (1) {
8605                         btrfs_tree_lock(path->nodes[level]);
8606                         btrfs_set_lock_blocking(path->nodes[level]);
8607                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8608
8609                         ret = btrfs_lookup_extent_info(trans, root,
8610                                                 path->nodes[level]->start,
8611                                                 level, 1, &wc->refs[level],
8612                                                 &wc->flags[level]);
8613                         if (ret < 0) {
8614                                 err = ret;
8615                                 goto out_end_trans;
8616                         }
8617                         BUG_ON(wc->refs[level] == 0);
8618
8619                         if (level == root_item->drop_level)
8620                                 break;
8621
8622                         btrfs_tree_unlock(path->nodes[level]);
8623                         path->locks[level] = 0;
8624                         WARN_ON(wc->refs[level] != 1);
8625                         level--;
8626                 }
8627         }
8628
8629         wc->level = level;
8630         wc->shared_level = -1;
8631         wc->stage = DROP_REFERENCE;
8632         wc->update_ref = update_ref;
8633         wc->keep_locks = 0;
8634         wc->for_reloc = for_reloc;
8635         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8636
8637         while (1) {
8638
8639                 ret = walk_down_tree(trans, root, path, wc);
8640                 if (ret < 0) {
8641                         err = ret;
8642                         break;
8643                 }
8644
8645                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
8646                 if (ret < 0) {
8647                         err = ret;
8648                         break;
8649                 }
8650
8651                 if (ret > 0) {
8652                         BUG_ON(wc->stage != DROP_REFERENCE);
8653                         break;
8654                 }
8655
8656                 if (wc->stage == DROP_REFERENCE) {
8657                         level = wc->level;
8658                         btrfs_node_key(path->nodes[level],
8659                                        &root_item->drop_progress,
8660                                        path->slots[level]);
8661                         root_item->drop_level = level;
8662                 }
8663
8664                 BUG_ON(wc->level == 0);
8665                 if (btrfs_should_end_transaction(trans, tree_root) ||
8666                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
8667                         ret = btrfs_update_root(trans, tree_root,
8668                                                 &root->root_key,
8669                                                 root_item);
8670                         if (ret) {
8671                                 btrfs_abort_transaction(trans, tree_root, ret);
8672                                 err = ret;
8673                                 goto out_end_trans;
8674                         }
8675
8676                         btrfs_end_transaction_throttle(trans, tree_root);
8677                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
8678                                 pr_debug("BTRFS: drop snapshot early exit\n");
8679                                 err = -EAGAIN;
8680                                 goto out_free;
8681                         }
8682
8683                         trans = btrfs_start_transaction(tree_root, 0);
8684                         if (IS_ERR(trans)) {
8685                                 err = PTR_ERR(trans);
8686                                 goto out_free;
8687                         }
8688                         if (block_rsv)
8689                                 trans->block_rsv = block_rsv;
8690                 }
8691         }
8692         btrfs_release_path(path);
8693         if (err)
8694                 goto out_end_trans;
8695
8696         ret = btrfs_del_root(trans, tree_root, &root->root_key);
8697         if (ret) {
8698                 btrfs_abort_transaction(trans, tree_root, ret);
8699                 goto out_end_trans;
8700         }
8701
8702         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
8703                 ret = btrfs_find_root(tree_root, &root->root_key, path,
8704                                       NULL, NULL);
8705                 if (ret < 0) {
8706                         btrfs_abort_transaction(trans, tree_root, ret);
8707                         err = ret;
8708                         goto out_end_trans;
8709                 } else if (ret > 0) {
8710                         /* if we fail to delete the orphan item this time
8711                          * around, it'll get picked up the next time.
8712                          *
8713                          * The most common failure here is just -ENOENT.
8714                          */
8715                         btrfs_del_orphan_item(trans, tree_root,
8716                                               root->root_key.objectid);
8717                 }
8718         }
8719
8720         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
8721                 btrfs_add_dropped_root(trans, root);
8722         } else {
8723                 free_extent_buffer(root->node);
8724                 free_extent_buffer(root->commit_root);
8725                 btrfs_put_fs_root(root);
8726         }
8727         root_dropped = true;
8728 out_end_trans:
8729         btrfs_end_transaction_throttle(trans, tree_root);
8730 out_free:
8731         kfree(wc);
8732         btrfs_free_path(path);
8733 out:
8734         /*
8735          * So if we need to stop dropping the snapshot for whatever reason we
8736          * need to make sure to add it back to the dead root list so that we
8737          * keep trying to do the work later.  This also cleans up roots if we
8738          * don't have it in the radix (like when we recover after a power fail
8739          * or unmount) so we don't leak memory.
8740          */
8741         if (!for_reloc && root_dropped == false)
8742                 btrfs_add_dead_root(root);
8743         if (err && err != -EAGAIN)
8744                 btrfs_std_error(root->fs_info, err, NULL);
8745         return err;
8746 }
8747
8748 /*
8749  * drop subtree rooted at tree block 'node'.
8750  *
8751  * NOTE: this function will unlock and release tree block 'node'
8752  * only used by relocation code
8753  */
8754 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
8755                         struct btrfs_root *root,
8756                         struct extent_buffer *node,
8757                         struct extent_buffer *parent)
8758 {
8759         struct btrfs_path *path;
8760         struct walk_control *wc;
8761         int level;
8762         int parent_level;
8763         int ret = 0;
8764         int wret;
8765
8766         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
8767
8768         path = btrfs_alloc_path();
8769         if (!path)
8770                 return -ENOMEM;
8771
8772         wc = kzalloc(sizeof(*wc), GFP_NOFS);
8773         if (!wc) {
8774                 btrfs_free_path(path);
8775                 return -ENOMEM;
8776         }
8777
8778         btrfs_assert_tree_locked(parent);
8779         parent_level = btrfs_header_level(parent);
8780         extent_buffer_get(parent);
8781         path->nodes[parent_level] = parent;
8782         path->slots[parent_level] = btrfs_header_nritems(parent);
8783
8784         btrfs_assert_tree_locked(node);
8785         level = btrfs_header_level(node);
8786         path->nodes[level] = node;
8787         path->slots[level] = 0;
8788         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8789
8790         wc->refs[parent_level] = 1;
8791         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8792         wc->level = level;
8793         wc->shared_level = -1;
8794         wc->stage = DROP_REFERENCE;
8795         wc->update_ref = 0;
8796         wc->keep_locks = 1;
8797         wc->for_reloc = 1;
8798         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
8799
8800         while (1) {
8801                 wret = walk_down_tree(trans, root, path, wc);
8802                 if (wret < 0) {
8803                         ret = wret;
8804                         break;
8805                 }
8806
8807                 wret = walk_up_tree(trans, root, path, wc, parent_level);
8808                 if (wret < 0)
8809                         ret = wret;
8810                 if (wret != 0)
8811                         break;
8812         }
8813
8814         kfree(wc);
8815         btrfs_free_path(path);
8816         return ret;
8817 }
8818
8819 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
8820 {
8821         u64 num_devices;
8822         u64 stripped;
8823
8824         /*
8825          * if restripe for this chunk_type is on pick target profile and
8826          * return, otherwise do the usual balance
8827          */
8828         stripped = get_restripe_target(root->fs_info, flags);
8829         if (stripped)
8830                 return extended_to_chunk(stripped);
8831
8832         num_devices = root->fs_info->fs_devices->rw_devices;
8833
8834         stripped = BTRFS_BLOCK_GROUP_RAID0 |
8835                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
8836                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
8837
8838         if (num_devices == 1) {
8839                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8840                 stripped = flags & ~stripped;
8841
8842                 /* turn raid0 into single device chunks */
8843                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
8844                         return stripped;
8845
8846                 /* turn mirroring into duplication */
8847                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
8848                              BTRFS_BLOCK_GROUP_RAID10))
8849                         return stripped | BTRFS_BLOCK_GROUP_DUP;
8850         } else {
8851                 /* they already had raid on here, just return */
8852                 if (flags & stripped)
8853                         return flags;
8854
8855                 stripped |= BTRFS_BLOCK_GROUP_DUP;
8856                 stripped = flags & ~stripped;
8857
8858                 /* switch duplicated blocks with raid1 */
8859                 if (flags & BTRFS_BLOCK_GROUP_DUP)
8860                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
8861
8862                 /* this is drive concat, leave it alone */
8863         }
8864
8865         return flags;
8866 }
8867
8868 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
8869 {
8870         struct btrfs_space_info *sinfo = cache->space_info;
8871         u64 num_bytes;
8872         u64 min_allocable_bytes;
8873         int ret = -ENOSPC;
8874
8875         /*
8876          * We need some metadata space and system metadata space for
8877          * allocating chunks in some corner cases until we force to set
8878          * it to be readonly.
8879          */
8880         if ((sinfo->flags &
8881              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
8882             !force)
8883                 min_allocable_bytes = 1 * 1024 * 1024;
8884         else
8885                 min_allocable_bytes = 0;
8886
8887         spin_lock(&sinfo->lock);
8888         spin_lock(&cache->lock);
8889
8890         if (cache->ro) {
8891                 cache->ro++;
8892                 ret = 0;
8893                 goto out;
8894         }
8895
8896         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8897                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8898
8899         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
8900             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
8901             min_allocable_bytes <= sinfo->total_bytes) {
8902                 sinfo->bytes_readonly += num_bytes;
8903                 cache->ro++;
8904                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
8905                 ret = 0;
8906         }
8907 out:
8908         spin_unlock(&cache->lock);
8909         spin_unlock(&sinfo->lock);
8910         return ret;
8911 }
8912
8913 int btrfs_inc_block_group_ro(struct btrfs_root *root,
8914                              struct btrfs_block_group_cache *cache)
8915
8916 {
8917         struct btrfs_trans_handle *trans;
8918         u64 alloc_flags;
8919         int ret;
8920
8921 again:
8922         trans = btrfs_join_transaction(root);
8923         if (IS_ERR(trans))
8924                 return PTR_ERR(trans);
8925
8926         /*
8927          * we're not allowed to set block groups readonly after the dirty
8928          * block groups cache has started writing.  If it already started,
8929          * back off and let this transaction commit
8930          */
8931         mutex_lock(&root->fs_info->ro_block_group_mutex);
8932         if (trans->transaction->dirty_bg_run) {
8933                 u64 transid = trans->transid;
8934
8935                 mutex_unlock(&root->fs_info->ro_block_group_mutex);
8936                 btrfs_end_transaction(trans, root);
8937
8938                 ret = btrfs_wait_for_commit(root, transid);
8939                 if (ret)
8940                         return ret;
8941                 goto again;
8942         }
8943
8944         /*
8945          * if we are changing raid levels, try to allocate a corresponding
8946          * block group with the new raid level.
8947          */
8948         alloc_flags = update_block_group_flags(root, cache->flags);
8949         if (alloc_flags != cache->flags) {
8950                 ret = do_chunk_alloc(trans, root, alloc_flags,
8951                                      CHUNK_ALLOC_FORCE);
8952                 /*
8953                  * ENOSPC is allowed here, we may have enough space
8954                  * already allocated at the new raid level to
8955                  * carry on
8956                  */
8957                 if (ret == -ENOSPC)
8958                         ret = 0;
8959                 if (ret < 0)
8960                         goto out;
8961         }
8962
8963         ret = inc_block_group_ro(cache, 0);
8964         if (!ret)
8965                 goto out;
8966         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
8967         ret = do_chunk_alloc(trans, root, alloc_flags,
8968                              CHUNK_ALLOC_FORCE);
8969         if (ret < 0)
8970                 goto out;
8971         ret = inc_block_group_ro(cache, 0);
8972 out:
8973         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
8974                 alloc_flags = update_block_group_flags(root, cache->flags);
8975                 lock_chunks(root->fs_info->chunk_root);
8976                 check_system_chunk(trans, root, alloc_flags);
8977                 unlock_chunks(root->fs_info->chunk_root);
8978         }
8979         mutex_unlock(&root->fs_info->ro_block_group_mutex);
8980
8981         btrfs_end_transaction(trans, root);
8982         return ret;
8983 }
8984
8985 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
8986                             struct btrfs_root *root, u64 type)
8987 {
8988         u64 alloc_flags = get_alloc_profile(root, type);
8989         return do_chunk_alloc(trans, root, alloc_flags,
8990                               CHUNK_ALLOC_FORCE);
8991 }
8992
8993 /*
8994  * helper to account the unused space of all the readonly block group in the
8995  * space_info. takes mirrors into account.
8996  */
8997 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
8998 {
8999         struct btrfs_block_group_cache *block_group;
9000         u64 free_bytes = 0;
9001         int factor;
9002
9003         /* It's df, we don't care if it's racey */
9004         if (list_empty(&sinfo->ro_bgs))
9005                 return 0;
9006
9007         spin_lock(&sinfo->lock);
9008         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9009                 spin_lock(&block_group->lock);
9010
9011                 if (!block_group->ro) {
9012                         spin_unlock(&block_group->lock);
9013                         continue;
9014                 }
9015
9016                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9017                                           BTRFS_BLOCK_GROUP_RAID10 |
9018                                           BTRFS_BLOCK_GROUP_DUP))
9019                         factor = 2;
9020                 else
9021                         factor = 1;
9022
9023                 free_bytes += (block_group->key.offset -
9024                                btrfs_block_group_used(&block_group->item)) *
9025                                factor;
9026
9027                 spin_unlock(&block_group->lock);
9028         }
9029         spin_unlock(&sinfo->lock);
9030
9031         return free_bytes;
9032 }
9033
9034 void btrfs_dec_block_group_ro(struct btrfs_root *root,
9035                               struct btrfs_block_group_cache *cache)
9036 {
9037         struct btrfs_space_info *sinfo = cache->space_info;
9038         u64 num_bytes;
9039
9040         BUG_ON(!cache->ro);
9041
9042         spin_lock(&sinfo->lock);
9043         spin_lock(&cache->lock);
9044         if (!--cache->ro) {
9045                 num_bytes = cache->key.offset - cache->reserved -
9046                             cache->pinned - cache->bytes_super -
9047                             btrfs_block_group_used(&cache->item);
9048                 sinfo->bytes_readonly -= num_bytes;
9049                 list_del_init(&cache->ro_list);
9050         }
9051         spin_unlock(&cache->lock);
9052         spin_unlock(&sinfo->lock);
9053 }
9054
9055 /*
9056  * checks to see if its even possible to relocate this block group.
9057  *
9058  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9059  * ok to go ahead and try.
9060  */
9061 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
9062 {
9063         struct btrfs_block_group_cache *block_group;
9064         struct btrfs_space_info *space_info;
9065         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
9066         struct btrfs_device *device;
9067         struct btrfs_trans_handle *trans;
9068         u64 min_free;
9069         u64 dev_min = 1;
9070         u64 dev_nr = 0;
9071         u64 target;
9072         int index;
9073         int full = 0;
9074         int ret = 0;
9075
9076         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
9077
9078         /* odd, couldn't find the block group, leave it alone */
9079         if (!block_group)
9080                 return -1;
9081
9082         min_free = btrfs_block_group_used(&block_group->item);
9083
9084         /* no bytes used, we're good */
9085         if (!min_free)
9086                 goto out;
9087
9088         space_info = block_group->space_info;
9089         spin_lock(&space_info->lock);
9090
9091         full = space_info->full;
9092
9093         /*
9094          * if this is the last block group we have in this space, we can't
9095          * relocate it unless we're able to allocate a new chunk below.
9096          *
9097          * Otherwise, we need to make sure we have room in the space to handle
9098          * all of the extents from this block group.  If we can, we're good
9099          */
9100         if ((space_info->total_bytes != block_group->key.offset) &&
9101             (space_info->bytes_used + space_info->bytes_reserved +
9102              space_info->bytes_pinned + space_info->bytes_readonly +
9103              min_free < space_info->total_bytes)) {
9104                 spin_unlock(&space_info->lock);
9105                 goto out;
9106         }
9107         spin_unlock(&space_info->lock);
9108
9109         /*
9110          * ok we don't have enough space, but maybe we have free space on our
9111          * devices to allocate new chunks for relocation, so loop through our
9112          * alloc devices and guess if we have enough space.  if this block
9113          * group is going to be restriped, run checks against the target
9114          * profile instead of the current one.
9115          */
9116         ret = -1;
9117
9118         /*
9119          * index:
9120          *      0: raid10
9121          *      1: raid1
9122          *      2: dup
9123          *      3: raid0
9124          *      4: single
9125          */
9126         target = get_restripe_target(root->fs_info, block_group->flags);
9127         if (target) {
9128                 index = __get_raid_index(extended_to_chunk(target));
9129         } else {
9130                 /*
9131                  * this is just a balance, so if we were marked as full
9132                  * we know there is no space for a new chunk
9133                  */
9134                 if (full)
9135                         goto out;
9136
9137                 index = get_block_group_index(block_group);
9138         }
9139
9140         if (index == BTRFS_RAID_RAID10) {
9141                 dev_min = 4;
9142                 /* Divide by 2 */
9143                 min_free >>= 1;
9144         } else if (index == BTRFS_RAID_RAID1) {
9145                 dev_min = 2;
9146         } else if (index == BTRFS_RAID_DUP) {
9147                 /* Multiply by 2 */
9148                 min_free <<= 1;
9149         } else if (index == BTRFS_RAID_RAID0) {
9150                 dev_min = fs_devices->rw_devices;
9151                 min_free = div64_u64(min_free, dev_min);
9152         }
9153
9154         /* We need to do this so that we can look at pending chunks */
9155         trans = btrfs_join_transaction(root);
9156         if (IS_ERR(trans)) {
9157                 ret = PTR_ERR(trans);
9158                 goto out;
9159         }
9160
9161         mutex_lock(&root->fs_info->chunk_mutex);
9162         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9163                 u64 dev_offset;
9164
9165                 /*
9166                  * check to make sure we can actually find a chunk with enough
9167                  * space to fit our block group in.
9168                  */
9169                 if (device->total_bytes > device->bytes_used + min_free &&
9170                     !device->is_tgtdev_for_dev_replace) {
9171                         ret = find_free_dev_extent(trans, device, min_free,
9172                                                    &dev_offset, NULL);
9173                         if (!ret)
9174                                 dev_nr++;
9175
9176                         if (dev_nr >= dev_min)
9177                                 break;
9178
9179                         ret = -1;
9180                 }
9181         }
9182         mutex_unlock(&root->fs_info->chunk_mutex);
9183         btrfs_end_transaction(trans, root);
9184 out:
9185         btrfs_put_block_group(block_group);
9186         return ret;
9187 }
9188
9189 static int find_first_block_group(struct btrfs_root *root,
9190                 struct btrfs_path *path, struct btrfs_key *key)
9191 {
9192         int ret = 0;
9193         struct btrfs_key found_key;
9194         struct extent_buffer *leaf;
9195         int slot;
9196
9197         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9198         if (ret < 0)
9199                 goto out;
9200
9201         while (1) {
9202                 slot = path->slots[0];
9203                 leaf = path->nodes[0];
9204                 if (slot >= btrfs_header_nritems(leaf)) {
9205                         ret = btrfs_next_leaf(root, path);
9206                         if (ret == 0)
9207                                 continue;
9208                         if (ret < 0)
9209                                 goto out;
9210                         break;
9211                 }
9212                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9213
9214                 if (found_key.objectid >= key->objectid &&
9215                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9216                         ret = 0;
9217                         goto out;
9218                 }
9219                 path->slots[0]++;
9220         }
9221 out:
9222         return ret;
9223 }
9224
9225 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9226 {
9227         struct btrfs_block_group_cache *block_group;
9228         u64 last = 0;
9229
9230         while (1) {
9231                 struct inode *inode;
9232
9233                 block_group = btrfs_lookup_first_block_group(info, last);
9234                 while (block_group) {
9235                         spin_lock(&block_group->lock);
9236                         if (block_group->iref)
9237                                 break;
9238                         spin_unlock(&block_group->lock);
9239                         block_group = next_block_group(info->tree_root,
9240                                                        block_group);
9241                 }
9242                 if (!block_group) {
9243                         if (last == 0)
9244                                 break;
9245                         last = 0;
9246                         continue;
9247                 }
9248
9249                 inode = block_group->inode;
9250                 block_group->iref = 0;
9251                 block_group->inode = NULL;
9252                 spin_unlock(&block_group->lock);
9253                 iput(inode);
9254                 last = block_group->key.objectid + block_group->key.offset;
9255                 btrfs_put_block_group(block_group);
9256         }
9257 }
9258
9259 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9260 {
9261         struct btrfs_block_group_cache *block_group;
9262         struct btrfs_space_info *space_info;
9263         struct btrfs_caching_control *caching_ctl;
9264         struct rb_node *n;
9265
9266         down_write(&info->commit_root_sem);
9267         while (!list_empty(&info->caching_block_groups)) {
9268                 caching_ctl = list_entry(info->caching_block_groups.next,
9269                                          struct btrfs_caching_control, list);
9270                 list_del(&caching_ctl->list);
9271                 put_caching_control(caching_ctl);
9272         }
9273         up_write(&info->commit_root_sem);
9274
9275         spin_lock(&info->unused_bgs_lock);
9276         while (!list_empty(&info->unused_bgs)) {
9277                 block_group = list_first_entry(&info->unused_bgs,
9278                                                struct btrfs_block_group_cache,
9279                                                bg_list);
9280                 list_del_init(&block_group->bg_list);
9281                 btrfs_put_block_group(block_group);
9282         }
9283         spin_unlock(&info->unused_bgs_lock);
9284
9285         spin_lock(&info->block_group_cache_lock);
9286         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9287                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9288                                        cache_node);
9289                 rb_erase(&block_group->cache_node,
9290                          &info->block_group_cache_tree);
9291                 RB_CLEAR_NODE(&block_group->cache_node);
9292                 spin_unlock(&info->block_group_cache_lock);
9293
9294                 down_write(&block_group->space_info->groups_sem);
9295                 list_del(&block_group->list);
9296                 up_write(&block_group->space_info->groups_sem);
9297
9298                 if (block_group->cached == BTRFS_CACHE_STARTED)
9299                         wait_block_group_cache_done(block_group);
9300
9301                 /*
9302                  * We haven't cached this block group, which means we could
9303                  * possibly have excluded extents on this block group.
9304                  */
9305                 if (block_group->cached == BTRFS_CACHE_NO ||
9306                     block_group->cached == BTRFS_CACHE_ERROR)
9307                         free_excluded_extents(info->extent_root, block_group);
9308
9309                 btrfs_remove_free_space_cache(block_group);
9310                 btrfs_put_block_group(block_group);
9311
9312                 spin_lock(&info->block_group_cache_lock);
9313         }
9314         spin_unlock(&info->block_group_cache_lock);
9315
9316         /* now that all the block groups are freed, go through and
9317          * free all the space_info structs.  This is only called during
9318          * the final stages of unmount, and so we know nobody is
9319          * using them.  We call synchronize_rcu() once before we start,
9320          * just to be on the safe side.
9321          */
9322         synchronize_rcu();
9323
9324         release_global_block_rsv(info);
9325
9326         while (!list_empty(&info->space_info)) {
9327                 int i;
9328
9329                 space_info = list_entry(info->space_info.next,
9330                                         struct btrfs_space_info,
9331                                         list);
9332                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
9333                         if (WARN_ON(space_info->bytes_pinned > 0 ||
9334                             space_info->bytes_reserved > 0 ||
9335                             space_info->bytes_may_use > 0)) {
9336                                 dump_space_info(space_info, 0, 0);
9337                         }
9338                 }
9339                 list_del(&space_info->list);
9340                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
9341                         struct kobject *kobj;
9342                         kobj = space_info->block_group_kobjs[i];
9343                         space_info->block_group_kobjs[i] = NULL;
9344                         if (kobj) {
9345                                 kobject_del(kobj);
9346                                 kobject_put(kobj);
9347                         }
9348                 }
9349                 kobject_del(&space_info->kobj);
9350                 kobject_put(&space_info->kobj);
9351         }
9352         return 0;
9353 }
9354
9355 static void __link_block_group(struct btrfs_space_info *space_info,
9356                                struct btrfs_block_group_cache *cache)
9357 {
9358         int index = get_block_group_index(cache);
9359         bool first = false;
9360
9361         down_write(&space_info->groups_sem);
9362         if (list_empty(&space_info->block_groups[index]))
9363                 first = true;
9364         list_add_tail(&cache->list, &space_info->block_groups[index]);
9365         up_write(&space_info->groups_sem);
9366
9367         if (first) {
9368                 struct raid_kobject *rkobj;
9369                 int ret;
9370
9371                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
9372                 if (!rkobj)
9373                         goto out_err;
9374                 rkobj->raid_type = index;
9375                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
9376                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
9377                                   "%s", get_raid_name(index));
9378                 if (ret) {
9379                         kobject_put(&rkobj->kobj);
9380                         goto out_err;
9381                 }
9382                 space_info->block_group_kobjs[index] = &rkobj->kobj;
9383         }
9384
9385         return;
9386 out_err:
9387         pr_warn("BTRFS: failed to add kobject for block cache. ignoring.\n");
9388 }
9389
9390 static struct btrfs_block_group_cache *
9391 btrfs_create_block_group_cache(struct btrfs_root *root, u64 start, u64 size)
9392 {
9393         struct btrfs_block_group_cache *cache;
9394
9395         cache = kzalloc(sizeof(*cache), GFP_NOFS);
9396         if (!cache)
9397                 return NULL;
9398
9399         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
9400                                         GFP_NOFS);
9401         if (!cache->free_space_ctl) {
9402                 kfree(cache);
9403                 return NULL;
9404         }
9405
9406         cache->key.objectid = start;
9407         cache->key.offset = size;
9408         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9409
9410         cache->sectorsize = root->sectorsize;
9411         cache->fs_info = root->fs_info;
9412         cache->full_stripe_len = btrfs_full_stripe_len(root,
9413                                                &root->fs_info->mapping_tree,
9414                                                start);
9415         atomic_set(&cache->count, 1);
9416         spin_lock_init(&cache->lock);
9417         init_rwsem(&cache->data_rwsem);
9418         INIT_LIST_HEAD(&cache->list);
9419         INIT_LIST_HEAD(&cache->cluster_list);
9420         INIT_LIST_HEAD(&cache->bg_list);
9421         INIT_LIST_HEAD(&cache->ro_list);
9422         INIT_LIST_HEAD(&cache->dirty_list);
9423         INIT_LIST_HEAD(&cache->io_list);
9424         btrfs_init_free_space_ctl(cache);
9425         atomic_set(&cache->trimming, 0);
9426
9427         return cache;
9428 }
9429
9430 int btrfs_read_block_groups(struct btrfs_root *root)
9431 {
9432         struct btrfs_path *path;
9433         int ret;
9434         struct btrfs_block_group_cache *cache;
9435         struct btrfs_fs_info *info = root->fs_info;
9436         struct btrfs_space_info *space_info;
9437         struct btrfs_key key;
9438         struct btrfs_key found_key;
9439         struct extent_buffer *leaf;
9440         int need_clear = 0;
9441         u64 cache_gen;
9442
9443         root = info->extent_root;
9444         key.objectid = 0;
9445         key.offset = 0;
9446         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
9447         path = btrfs_alloc_path();
9448         if (!path)
9449                 return -ENOMEM;
9450         path->reada = 1;
9451
9452         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
9453         if (btrfs_test_opt(root, SPACE_CACHE) &&
9454             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
9455                 need_clear = 1;
9456         if (btrfs_test_opt(root, CLEAR_CACHE))
9457                 need_clear = 1;
9458
9459         while (1) {
9460                 ret = find_first_block_group(root, path, &key);
9461                 if (ret > 0)
9462                         break;
9463                 if (ret != 0)
9464                         goto error;
9465
9466                 leaf = path->nodes[0];
9467                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
9468
9469                 cache = btrfs_create_block_group_cache(root, found_key.objectid,
9470                                                        found_key.offset);
9471                 if (!cache) {
9472                         ret = -ENOMEM;
9473                         goto error;
9474                 }
9475
9476                 if (need_clear) {
9477                         /*
9478                          * When we mount with old space cache, we need to
9479                          * set BTRFS_DC_CLEAR and set dirty flag.
9480                          *
9481                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
9482                          *    truncate the old free space cache inode and
9483                          *    setup a new one.
9484                          * b) Setting 'dirty flag' makes sure that we flush
9485                          *    the new space cache info onto disk.
9486                          */
9487                         if (btrfs_test_opt(root, SPACE_CACHE))
9488                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
9489                 }
9490
9491                 read_extent_buffer(leaf, &cache->item,
9492                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
9493                                    sizeof(cache->item));
9494                 cache->flags = btrfs_block_group_flags(&cache->item);
9495
9496                 key.objectid = found_key.objectid + found_key.offset;
9497                 btrfs_release_path(path);
9498
9499                 /*
9500                  * We need to exclude the super stripes now so that the space
9501                  * info has super bytes accounted for, otherwise we'll think
9502                  * we have more space than we actually do.
9503                  */
9504                 ret = exclude_super_stripes(root, cache);
9505                 if (ret) {
9506                         /*
9507                          * We may have excluded something, so call this just in
9508                          * case.
9509                          */
9510                         free_excluded_extents(root, cache);
9511                         btrfs_put_block_group(cache);
9512                         goto error;
9513                 }
9514
9515                 /*
9516                  * check for two cases, either we are full, and therefore
9517                  * don't need to bother with the caching work since we won't
9518                  * find any space, or we are empty, and we can just add all
9519                  * the space in and be done with it.  This saves us _alot_ of
9520                  * time, particularly in the full case.
9521                  */
9522                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
9523                         cache->last_byte_to_unpin = (u64)-1;
9524                         cache->cached = BTRFS_CACHE_FINISHED;
9525                         free_excluded_extents(root, cache);
9526                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9527                         cache->last_byte_to_unpin = (u64)-1;
9528                         cache->cached = BTRFS_CACHE_FINISHED;
9529                         add_new_free_space(cache, root->fs_info,
9530                                            found_key.objectid,
9531                                            found_key.objectid +
9532                                            found_key.offset);
9533                         free_excluded_extents(root, cache);
9534                 }
9535
9536                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
9537                 if (ret) {
9538                         btrfs_remove_free_space_cache(cache);
9539                         btrfs_put_block_group(cache);
9540                         goto error;
9541                 }
9542
9543                 ret = update_space_info(info, cache->flags, found_key.offset,
9544                                         btrfs_block_group_used(&cache->item),
9545                                         &space_info);
9546                 if (ret) {
9547                         btrfs_remove_free_space_cache(cache);
9548                         spin_lock(&info->block_group_cache_lock);
9549                         rb_erase(&cache->cache_node,
9550                                  &info->block_group_cache_tree);
9551                         RB_CLEAR_NODE(&cache->cache_node);
9552                         spin_unlock(&info->block_group_cache_lock);
9553                         btrfs_put_block_group(cache);
9554                         goto error;
9555                 }
9556
9557                 cache->space_info = space_info;
9558                 spin_lock(&cache->space_info->lock);
9559                 cache->space_info->bytes_readonly += cache->bytes_super;
9560                 spin_unlock(&cache->space_info->lock);
9561
9562                 __link_block_group(space_info, cache);
9563
9564                 set_avail_alloc_bits(root->fs_info, cache->flags);
9565                 if (btrfs_chunk_readonly(root, cache->key.objectid)) {
9566                         inc_block_group_ro(cache, 1);
9567                 } else if (btrfs_block_group_used(&cache->item) == 0) {
9568                         spin_lock(&info->unused_bgs_lock);
9569                         /* Should always be true but just in case. */
9570                         if (list_empty(&cache->bg_list)) {
9571                                 btrfs_get_block_group(cache);
9572                                 list_add_tail(&cache->bg_list,
9573                                               &info->unused_bgs);
9574                         }
9575                         spin_unlock(&info->unused_bgs_lock);
9576                 }
9577         }
9578
9579         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
9580                 if (!(get_alloc_profile(root, space_info->flags) &
9581                       (BTRFS_BLOCK_GROUP_RAID10 |
9582                        BTRFS_BLOCK_GROUP_RAID1 |
9583                        BTRFS_BLOCK_GROUP_RAID5 |
9584                        BTRFS_BLOCK_GROUP_RAID6 |
9585                        BTRFS_BLOCK_GROUP_DUP)))
9586                         continue;
9587                 /*
9588                  * avoid allocating from un-mirrored block group if there are
9589                  * mirrored block groups.
9590                  */
9591                 list_for_each_entry(cache,
9592                                 &space_info->block_groups[BTRFS_RAID_RAID0],
9593                                 list)
9594                         inc_block_group_ro(cache, 1);
9595                 list_for_each_entry(cache,
9596                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
9597                                 list)
9598                         inc_block_group_ro(cache, 1);
9599         }
9600
9601         init_global_block_rsv(info);
9602         ret = 0;
9603 error:
9604         btrfs_free_path(path);
9605         return ret;
9606 }
9607
9608 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
9609                                        struct btrfs_root *root)
9610 {
9611         struct btrfs_block_group_cache *block_group, *tmp;
9612         struct btrfs_root *extent_root = root->fs_info->extent_root;
9613         struct btrfs_block_group_item item;
9614         struct btrfs_key key;
9615         int ret = 0;
9616         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
9617
9618         trans->can_flush_pending_bgs = false;
9619         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
9620                 if (ret)
9621                         goto next;
9622
9623                 spin_lock(&block_group->lock);
9624                 memcpy(&item, &block_group->item, sizeof(item));
9625                 memcpy(&key, &block_group->key, sizeof(key));
9626                 spin_unlock(&block_group->lock);
9627
9628                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
9629                                         sizeof(item));
9630                 if (ret)
9631                         btrfs_abort_transaction(trans, extent_root, ret);
9632                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
9633                                                key.objectid, key.offset);
9634                 if (ret)
9635                         btrfs_abort_transaction(trans, extent_root, ret);
9636 next:
9637                 list_del_init(&block_group->bg_list);
9638         }
9639         trans->can_flush_pending_bgs = can_flush_pending_bgs;
9640 }
9641
9642 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
9643                            struct btrfs_root *root, u64 bytes_used,
9644                            u64 type, u64 chunk_objectid, u64 chunk_offset,
9645                            u64 size)
9646 {
9647         int ret;
9648         struct btrfs_root *extent_root;
9649         struct btrfs_block_group_cache *cache;
9650
9651         extent_root = root->fs_info->extent_root;
9652
9653         btrfs_set_log_full_commit(root->fs_info, trans);
9654
9655         cache = btrfs_create_block_group_cache(root, chunk_offset, size);
9656         if (!cache)
9657                 return -ENOMEM;
9658
9659         btrfs_set_block_group_used(&cache->item, bytes_used);
9660         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
9661         btrfs_set_block_group_flags(&cache->item, type);
9662
9663         cache->flags = type;
9664         cache->last_byte_to_unpin = (u64)-1;
9665         cache->cached = BTRFS_CACHE_FINISHED;
9666         ret = exclude_super_stripes(root, cache);
9667         if (ret) {
9668                 /*
9669                  * We may have excluded something, so call this just in
9670                  * case.
9671                  */
9672                 free_excluded_extents(root, cache);
9673                 btrfs_put_block_group(cache);
9674                 return ret;
9675         }
9676
9677         add_new_free_space(cache, root->fs_info, chunk_offset,
9678                            chunk_offset + size);
9679
9680         free_excluded_extents(root, cache);
9681
9682         /*
9683          * Call to ensure the corresponding space_info object is created and
9684          * assigned to our block group, but don't update its counters just yet.
9685          * We want our bg to be added to the rbtree with its ->space_info set.
9686          */
9687         ret = update_space_info(root->fs_info, cache->flags, 0, 0,
9688                                 &cache->space_info);
9689         if (ret) {
9690                 btrfs_remove_free_space_cache(cache);
9691                 btrfs_put_block_group(cache);
9692                 return ret;
9693         }
9694
9695         ret = btrfs_add_block_group_cache(root->fs_info, cache);
9696         if (ret) {
9697                 btrfs_remove_free_space_cache(cache);
9698                 btrfs_put_block_group(cache);
9699                 return ret;
9700         }
9701
9702         /*
9703          * Now that our block group has its ->space_info set and is inserted in
9704          * the rbtree, update the space info's counters.
9705          */
9706         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
9707                                 &cache->space_info);
9708         if (ret) {
9709                 btrfs_remove_free_space_cache(cache);
9710                 spin_lock(&root->fs_info->block_group_cache_lock);
9711                 rb_erase(&cache->cache_node,
9712                          &root->fs_info->block_group_cache_tree);
9713                 RB_CLEAR_NODE(&cache->cache_node);
9714                 spin_unlock(&root->fs_info->block_group_cache_lock);
9715                 btrfs_put_block_group(cache);
9716                 return ret;
9717         }
9718         update_global_block_rsv(root->fs_info);
9719
9720         spin_lock(&cache->space_info->lock);
9721         cache->space_info->bytes_readonly += cache->bytes_super;
9722         spin_unlock(&cache->space_info->lock);
9723
9724         __link_block_group(cache->space_info, cache);
9725
9726         list_add_tail(&cache->bg_list, &trans->new_bgs);
9727
9728         set_avail_alloc_bits(extent_root->fs_info, type);
9729
9730         return 0;
9731 }
9732
9733 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
9734 {
9735         u64 extra_flags = chunk_to_extended(flags) &
9736                                 BTRFS_EXTENDED_PROFILE_MASK;
9737
9738         write_seqlock(&fs_info->profiles_lock);
9739         if (flags & BTRFS_BLOCK_GROUP_DATA)
9740                 fs_info->avail_data_alloc_bits &= ~extra_flags;
9741         if (flags & BTRFS_BLOCK_GROUP_METADATA)
9742                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
9743         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
9744                 fs_info->avail_system_alloc_bits &= ~extra_flags;
9745         write_sequnlock(&fs_info->profiles_lock);
9746 }
9747
9748 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
9749                              struct btrfs_root *root, u64 group_start,
9750                              struct extent_map *em)
9751 {
9752         struct btrfs_path *path;
9753         struct btrfs_block_group_cache *block_group;
9754         struct btrfs_free_cluster *cluster;
9755         struct btrfs_root *tree_root = root->fs_info->tree_root;
9756         struct btrfs_key key;
9757         struct inode *inode;
9758         struct kobject *kobj = NULL;
9759         int ret;
9760         int index;
9761         int factor;
9762         struct btrfs_caching_control *caching_ctl = NULL;
9763         bool remove_em;
9764
9765         root = root->fs_info->extent_root;
9766
9767         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
9768         BUG_ON(!block_group);
9769         BUG_ON(!block_group->ro);
9770
9771         /*
9772          * Free the reserved super bytes from this block group before
9773          * remove it.
9774          */
9775         free_excluded_extents(root, block_group);
9776
9777         memcpy(&key, &block_group->key, sizeof(key));
9778         index = get_block_group_index(block_group);
9779         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
9780                                   BTRFS_BLOCK_GROUP_RAID1 |
9781                                   BTRFS_BLOCK_GROUP_RAID10))
9782                 factor = 2;
9783         else
9784                 factor = 1;
9785
9786         /* make sure this block group isn't part of an allocation cluster */
9787         cluster = &root->fs_info->data_alloc_cluster;
9788         spin_lock(&cluster->refill_lock);
9789         btrfs_return_cluster_to_free_space(block_group, cluster);
9790         spin_unlock(&cluster->refill_lock);
9791
9792         /*
9793          * make sure this block group isn't part of a metadata
9794          * allocation cluster
9795          */
9796         cluster = &root->fs_info->meta_alloc_cluster;
9797         spin_lock(&cluster->refill_lock);
9798         btrfs_return_cluster_to_free_space(block_group, cluster);
9799         spin_unlock(&cluster->refill_lock);
9800
9801         path = btrfs_alloc_path();
9802         if (!path) {
9803                 ret = -ENOMEM;
9804                 goto out;
9805         }
9806
9807         /*
9808          * get the inode first so any iput calls done for the io_list
9809          * aren't the final iput (no unlinks allowed now)
9810          */
9811         inode = lookup_free_space_inode(tree_root, block_group, path);
9812
9813         mutex_lock(&trans->transaction->cache_write_mutex);
9814         /*
9815          * make sure our free spache cache IO is done before remove the
9816          * free space inode
9817          */
9818         spin_lock(&trans->transaction->dirty_bgs_lock);
9819         if (!list_empty(&block_group->io_list)) {
9820                 list_del_init(&block_group->io_list);
9821
9822                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
9823
9824                 spin_unlock(&trans->transaction->dirty_bgs_lock);
9825                 btrfs_wait_cache_io(root, trans, block_group,
9826                                     &block_group->io_ctl, path,
9827                                     block_group->key.objectid);
9828                 btrfs_put_block_group(block_group);
9829                 spin_lock(&trans->transaction->dirty_bgs_lock);
9830         }
9831
9832         if (!list_empty(&block_group->dirty_list)) {
9833                 list_del_init(&block_group->dirty_list);
9834                 btrfs_put_block_group(block_group);
9835         }
9836         spin_unlock(&trans->transaction->dirty_bgs_lock);
9837         mutex_unlock(&trans->transaction->cache_write_mutex);
9838
9839         if (!IS_ERR(inode)) {
9840                 ret = btrfs_orphan_add(trans, inode);
9841                 if (ret) {
9842                         btrfs_add_delayed_iput(inode);
9843                         goto out;
9844                 }
9845                 clear_nlink(inode);
9846                 /* One for the block groups ref */
9847                 spin_lock(&block_group->lock);
9848                 if (block_group->iref) {
9849                         block_group->iref = 0;
9850                         block_group->inode = NULL;
9851                         spin_unlock(&block_group->lock);
9852                         iput(inode);
9853                 } else {
9854                         spin_unlock(&block_group->lock);
9855                 }
9856                 /* One for our lookup ref */
9857                 btrfs_add_delayed_iput(inode);
9858         }
9859
9860         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
9861         key.offset = block_group->key.objectid;
9862         key.type = 0;
9863
9864         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
9865         if (ret < 0)
9866                 goto out;
9867         if (ret > 0)
9868                 btrfs_release_path(path);
9869         if (ret == 0) {
9870                 ret = btrfs_del_item(trans, tree_root, path);
9871                 if (ret)
9872                         goto out;
9873                 btrfs_release_path(path);
9874         }
9875
9876         spin_lock(&root->fs_info->block_group_cache_lock);
9877         rb_erase(&block_group->cache_node,
9878                  &root->fs_info->block_group_cache_tree);
9879         RB_CLEAR_NODE(&block_group->cache_node);
9880
9881         if (root->fs_info->first_logical_byte == block_group->key.objectid)
9882                 root->fs_info->first_logical_byte = (u64)-1;
9883         spin_unlock(&root->fs_info->block_group_cache_lock);
9884
9885         down_write(&block_group->space_info->groups_sem);
9886         /*
9887          * we must use list_del_init so people can check to see if they
9888          * are still on the list after taking the semaphore
9889          */
9890         list_del_init(&block_group->list);
9891         if (list_empty(&block_group->space_info->block_groups[index])) {
9892                 kobj = block_group->space_info->block_group_kobjs[index];
9893                 block_group->space_info->block_group_kobjs[index] = NULL;
9894                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
9895         }
9896         up_write(&block_group->space_info->groups_sem);
9897         if (kobj) {
9898                 kobject_del(kobj);
9899                 kobject_put(kobj);
9900         }
9901
9902         if (block_group->has_caching_ctl)
9903                 caching_ctl = get_caching_control(block_group);
9904         if (block_group->cached == BTRFS_CACHE_STARTED)
9905                 wait_block_group_cache_done(block_group);
9906         if (block_group->has_caching_ctl) {
9907                 down_write(&root->fs_info->commit_root_sem);
9908                 if (!caching_ctl) {
9909                         struct btrfs_caching_control *ctl;
9910
9911                         list_for_each_entry(ctl,
9912                                     &root->fs_info->caching_block_groups, list)
9913                                 if (ctl->block_group == block_group) {
9914                                         caching_ctl = ctl;
9915                                         atomic_inc(&caching_ctl->count);
9916                                         break;
9917                                 }
9918                 }
9919                 if (caching_ctl)
9920                         list_del_init(&caching_ctl->list);
9921                 up_write(&root->fs_info->commit_root_sem);
9922                 if (caching_ctl) {
9923                         /* Once for the caching bgs list and once for us. */
9924                         put_caching_control(caching_ctl);
9925                         put_caching_control(caching_ctl);
9926                 }
9927         }
9928
9929         spin_lock(&trans->transaction->dirty_bgs_lock);
9930         if (!list_empty(&block_group->dirty_list)) {
9931                 WARN_ON(1);
9932         }
9933         if (!list_empty(&block_group->io_list)) {
9934                 WARN_ON(1);
9935         }
9936         spin_unlock(&trans->transaction->dirty_bgs_lock);
9937         btrfs_remove_free_space_cache(block_group);
9938
9939         spin_lock(&block_group->space_info->lock);
9940         list_del_init(&block_group->ro_list);
9941
9942         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
9943                 WARN_ON(block_group->space_info->total_bytes
9944                         < block_group->key.offset);
9945                 WARN_ON(block_group->space_info->bytes_readonly
9946                         < block_group->key.offset);
9947                 WARN_ON(block_group->space_info->disk_total
9948                         < block_group->key.offset * factor);
9949         }
9950         block_group->space_info->total_bytes -= block_group->key.offset;
9951         block_group->space_info->bytes_readonly -= block_group->key.offset;
9952         block_group->space_info->disk_total -= block_group->key.offset * factor;
9953
9954         spin_unlock(&block_group->space_info->lock);
9955
9956         memcpy(&key, &block_group->key, sizeof(key));
9957
9958         lock_chunks(root);
9959         if (!list_empty(&em->list)) {
9960                 /* We're in the transaction->pending_chunks list. */
9961                 free_extent_map(em);
9962         }
9963         spin_lock(&block_group->lock);
9964         block_group->removed = 1;
9965         /*
9966          * At this point trimming can't start on this block group, because we
9967          * removed the block group from the tree fs_info->block_group_cache_tree
9968          * so no one can't find it anymore and even if someone already got this
9969          * block group before we removed it from the rbtree, they have already
9970          * incremented block_group->trimming - if they didn't, they won't find
9971          * any free space entries because we already removed them all when we
9972          * called btrfs_remove_free_space_cache().
9973          *
9974          * And we must not remove the extent map from the fs_info->mapping_tree
9975          * to prevent the same logical address range and physical device space
9976          * ranges from being reused for a new block group. This is because our
9977          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
9978          * completely transactionless, so while it is trimming a range the
9979          * currently running transaction might finish and a new one start,
9980          * allowing for new block groups to be created that can reuse the same
9981          * physical device locations unless we take this special care.
9982          *
9983          * There may also be an implicit trim operation if the file system
9984          * is mounted with -odiscard. The same protections must remain
9985          * in place until the extents have been discarded completely when
9986          * the transaction commit has completed.
9987          */
9988         remove_em = (atomic_read(&block_group->trimming) == 0);
9989         /*
9990          * Make sure a trimmer task always sees the em in the pinned_chunks list
9991          * if it sees block_group->removed == 1 (needs to lock block_group->lock
9992          * before checking block_group->removed).
9993          */
9994         if (!remove_em) {
9995                 /*
9996                  * Our em might be in trans->transaction->pending_chunks which
9997                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
9998                  * and so is the fs_info->pinned_chunks list.
9999                  *
10000                  * So at this point we must be holding the chunk_mutex to avoid
10001                  * any races with chunk allocation (more specifically at
10002                  * volumes.c:contains_pending_extent()), to ensure it always
10003                  * sees the em, either in the pending_chunks list or in the
10004                  * pinned_chunks list.
10005                  */
10006                 list_move_tail(&em->list, &root->fs_info->pinned_chunks);
10007         }
10008         spin_unlock(&block_group->lock);
10009
10010         if (remove_em) {
10011                 struct extent_map_tree *em_tree;
10012
10013                 em_tree = &root->fs_info->mapping_tree.map_tree;
10014                 write_lock(&em_tree->lock);
10015                 /*
10016                  * The em might be in the pending_chunks list, so make sure the
10017                  * chunk mutex is locked, since remove_extent_mapping() will
10018                  * delete us from that list.
10019                  */
10020                 remove_extent_mapping(em_tree, em);
10021                 write_unlock(&em_tree->lock);
10022                 /* once for the tree */
10023                 free_extent_map(em);
10024         }
10025
10026         unlock_chunks(root);
10027
10028         btrfs_put_block_group(block_group);
10029         btrfs_put_block_group(block_group);
10030
10031         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10032         if (ret > 0)
10033                 ret = -EIO;
10034         if (ret < 0)
10035                 goto out;
10036
10037         ret = btrfs_del_item(trans, root, path);
10038 out:
10039         btrfs_free_path(path);
10040         return ret;
10041 }
10042
10043 /*
10044  * Process the unused_bgs list and remove any that don't have any allocated
10045  * space inside of them.
10046  */
10047 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10048 {
10049         struct btrfs_block_group_cache *block_group;
10050         struct btrfs_space_info *space_info;
10051         struct btrfs_root *root = fs_info->extent_root;
10052         struct btrfs_trans_handle *trans;
10053         int ret = 0;
10054
10055         if (!fs_info->open)
10056                 return;
10057
10058         spin_lock(&fs_info->unused_bgs_lock);
10059         while (!list_empty(&fs_info->unused_bgs)) {
10060                 u64 start, end;
10061                 int trimming;
10062
10063                 block_group = list_first_entry(&fs_info->unused_bgs,
10064                                                struct btrfs_block_group_cache,
10065                                                bg_list);
10066                 space_info = block_group->space_info;
10067                 list_del_init(&block_group->bg_list);
10068                 if (ret || btrfs_mixed_space_info(space_info)) {
10069                         btrfs_put_block_group(block_group);
10070                         continue;
10071                 }
10072                 spin_unlock(&fs_info->unused_bgs_lock);
10073
10074                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
10075
10076                 /* Don't want to race with allocators so take the groups_sem */
10077                 down_write(&space_info->groups_sem);
10078                 spin_lock(&block_group->lock);
10079                 if (block_group->reserved ||
10080                     btrfs_block_group_used(&block_group->item) ||
10081                     block_group->ro) {
10082                         /*
10083                          * We want to bail if we made new allocations or have
10084                          * outstanding allocations in this block group.  We do
10085                          * the ro check in case balance is currently acting on
10086                          * this block group.
10087                          */
10088                         spin_unlock(&block_group->lock);
10089                         up_write(&space_info->groups_sem);
10090                         goto next;
10091                 }
10092                 spin_unlock(&block_group->lock);
10093
10094                 /* We don't want to force the issue, only flip if it's ok. */
10095                 ret = inc_block_group_ro(block_group, 0);
10096                 up_write(&space_info->groups_sem);
10097                 if (ret < 0) {
10098                         ret = 0;
10099                         goto next;
10100                 }
10101
10102                 /*
10103                  * Want to do this before we do anything else so we can recover
10104                  * properly if we fail to join the transaction.
10105                  */
10106                 /* 1 for btrfs_orphan_reserve_metadata() */
10107                 trans = btrfs_start_transaction(root, 1);
10108                 if (IS_ERR(trans)) {
10109                         btrfs_dec_block_group_ro(root, block_group);
10110                         ret = PTR_ERR(trans);
10111                         goto next;
10112                 }
10113
10114                 /*
10115                  * We could have pending pinned extents for this block group,
10116                  * just delete them, we don't care about them anymore.
10117                  */
10118                 start = block_group->key.objectid;
10119                 end = start + block_group->key.offset - 1;
10120                 /*
10121                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10122                  * btrfs_finish_extent_commit(). If we are at transaction N,
10123                  * another task might be running finish_extent_commit() for the
10124                  * previous transaction N - 1, and have seen a range belonging
10125                  * to the block group in freed_extents[] before we were able to
10126                  * clear the whole block group range from freed_extents[]. This
10127                  * means that task can lookup for the block group after we
10128                  * unpinned it from freed_extents[] and removed it, leading to
10129                  * a BUG_ON() at btrfs_unpin_extent_range().
10130                  */
10131                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10132                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10133                                   EXTENT_DIRTY, GFP_NOFS);
10134                 if (ret) {
10135                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10136                         btrfs_dec_block_group_ro(root, block_group);
10137                         goto end_trans;
10138                 }
10139                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10140                                   EXTENT_DIRTY, GFP_NOFS);
10141                 if (ret) {
10142                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10143                         btrfs_dec_block_group_ro(root, block_group);
10144                         goto end_trans;
10145                 }
10146                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10147
10148                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10149                 spin_lock(&space_info->lock);
10150                 spin_lock(&block_group->lock);
10151
10152                 space_info->bytes_pinned -= block_group->pinned;
10153                 space_info->bytes_readonly += block_group->pinned;
10154                 percpu_counter_add(&space_info->total_bytes_pinned,
10155                                    -block_group->pinned);
10156                 block_group->pinned = 0;
10157
10158                 spin_unlock(&block_group->lock);
10159                 spin_unlock(&space_info->lock);
10160
10161                 /* DISCARD can flip during remount */
10162                 trimming = btrfs_test_opt(root, DISCARD);
10163
10164                 /* Implicit trim during transaction commit. */
10165                 if (trimming)
10166                         btrfs_get_block_group_trimming(block_group);
10167
10168                 /*
10169                  * Btrfs_remove_chunk will abort the transaction if things go
10170                  * horribly wrong.
10171                  */
10172                 ret = btrfs_remove_chunk(trans, root,
10173                                          block_group->key.objectid);
10174
10175                 if (ret) {
10176                         if (trimming)
10177                                 btrfs_put_block_group_trimming(block_group);
10178                         goto end_trans;
10179                 }
10180
10181                 /*
10182                  * If we're not mounted with -odiscard, we can just forget
10183                  * about this block group. Otherwise we'll need to wait
10184                  * until transaction commit to do the actual discard.
10185                  */
10186                 if (trimming) {
10187                         WARN_ON(!list_empty(&block_group->bg_list));
10188                         spin_lock(&trans->transaction->deleted_bgs_lock);
10189                         list_move(&block_group->bg_list,
10190                                   &trans->transaction->deleted_bgs);
10191                         spin_unlock(&trans->transaction->deleted_bgs_lock);
10192                         btrfs_get_block_group(block_group);
10193                 }
10194 end_trans:
10195                 btrfs_end_transaction(trans, root);
10196 next:
10197                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
10198                 btrfs_put_block_group(block_group);
10199                 spin_lock(&fs_info->unused_bgs_lock);
10200         }
10201         spin_unlock(&fs_info->unused_bgs_lock);
10202 }
10203
10204 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
10205 {
10206         struct btrfs_space_info *space_info;
10207         struct btrfs_super_block *disk_super;
10208         u64 features;
10209         u64 flags;
10210         int mixed = 0;
10211         int ret;
10212
10213         disk_super = fs_info->super_copy;
10214         if (!btrfs_super_root(disk_super))
10215                 return 1;
10216
10217         features = btrfs_super_incompat_flags(disk_super);
10218         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
10219                 mixed = 1;
10220
10221         flags = BTRFS_BLOCK_GROUP_SYSTEM;
10222         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10223         if (ret)
10224                 goto out;
10225
10226         if (mixed) {
10227                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
10228                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10229         } else {
10230                 flags = BTRFS_BLOCK_GROUP_METADATA;
10231                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10232                 if (ret)
10233                         goto out;
10234
10235                 flags = BTRFS_BLOCK_GROUP_DATA;
10236                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
10237         }
10238 out:
10239         return ret;
10240 }
10241
10242 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
10243 {
10244         return unpin_extent_range(root, start, end, false);
10245 }
10246
10247 /*
10248  * It used to be that old block groups would be left around forever.
10249  * Iterating over them would be enough to trim unused space.  Since we
10250  * now automatically remove them, we also need to iterate over unallocated
10251  * space.
10252  *
10253  * We don't want a transaction for this since the discard may take a
10254  * substantial amount of time.  We don't require that a transaction be
10255  * running, but we do need to take a running transaction into account
10256  * to ensure that we're not discarding chunks that were released in
10257  * the current transaction.
10258  *
10259  * Holding the chunks lock will prevent other threads from allocating
10260  * or releasing chunks, but it won't prevent a running transaction
10261  * from committing and releasing the memory that the pending chunks
10262  * list head uses.  For that, we need to take a reference to the
10263  * transaction.
10264  */
10265 static int btrfs_trim_free_extents(struct btrfs_device *device,
10266                                    u64 minlen, u64 *trimmed)
10267 {
10268         u64 start = 0, len = 0;
10269         int ret;
10270
10271         *trimmed = 0;
10272
10273         /* Not writeable = nothing to do. */
10274         if (!device->writeable)
10275                 return 0;
10276
10277         /* No free space = nothing to do. */
10278         if (device->total_bytes <= device->bytes_used)
10279                 return 0;
10280
10281         ret = 0;
10282
10283         while (1) {
10284                 struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
10285                 struct btrfs_transaction *trans;
10286                 u64 bytes;
10287
10288                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
10289                 if (ret)
10290                         return ret;
10291
10292                 down_read(&fs_info->commit_root_sem);
10293
10294                 spin_lock(&fs_info->trans_lock);
10295                 trans = fs_info->running_transaction;
10296                 if (trans)
10297                         atomic_inc(&trans->use_count);
10298                 spin_unlock(&fs_info->trans_lock);
10299
10300                 ret = find_free_dev_extent_start(trans, device, minlen, start,
10301                                                  &start, &len);
10302                 if (trans)
10303                         btrfs_put_transaction(trans);
10304
10305                 if (ret) {
10306                         up_read(&fs_info->commit_root_sem);
10307                         mutex_unlock(&fs_info->chunk_mutex);
10308                         if (ret == -ENOSPC)
10309                                 ret = 0;
10310                         break;
10311                 }
10312
10313                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
10314                 up_read(&fs_info->commit_root_sem);
10315                 mutex_unlock(&fs_info->chunk_mutex);
10316
10317                 if (ret)
10318                         break;
10319
10320                 start += len;
10321                 *trimmed += bytes;
10322
10323                 if (fatal_signal_pending(current)) {
10324                         ret = -ERESTARTSYS;
10325                         break;
10326                 }
10327
10328                 cond_resched();
10329         }
10330
10331         return ret;
10332 }
10333
10334 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
10335 {
10336         struct btrfs_fs_info *fs_info = root->fs_info;
10337         struct btrfs_block_group_cache *cache = NULL;
10338         struct btrfs_device *device;
10339         struct list_head *devices;
10340         u64 group_trimmed;
10341         u64 start;
10342         u64 end;
10343         u64 trimmed = 0;
10344         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
10345         int ret = 0;
10346
10347         /*
10348          * try to trim all FS space, our block group may start from non-zero.
10349          */
10350         if (range->len == total_bytes)
10351                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
10352         else
10353                 cache = btrfs_lookup_block_group(fs_info, range->start);
10354
10355         while (cache) {
10356                 if (cache->key.objectid >= (range->start + range->len)) {
10357                         btrfs_put_block_group(cache);
10358                         break;
10359                 }
10360
10361                 start = max(range->start, cache->key.objectid);
10362                 end = min(range->start + range->len,
10363                                 cache->key.objectid + cache->key.offset);
10364
10365                 if (end - start >= range->minlen) {
10366                         if (!block_group_cache_done(cache)) {
10367                                 ret = cache_block_group(cache, 0);
10368                                 if (ret) {
10369                                         btrfs_put_block_group(cache);
10370                                         break;
10371                                 }
10372                                 ret = wait_block_group_cache_done(cache);
10373                                 if (ret) {
10374                                         btrfs_put_block_group(cache);
10375                                         break;
10376                                 }
10377                         }
10378                         ret = btrfs_trim_block_group(cache,
10379                                                      &group_trimmed,
10380                                                      start,
10381                                                      end,
10382                                                      range->minlen);
10383
10384                         trimmed += group_trimmed;
10385                         if (ret) {
10386                                 btrfs_put_block_group(cache);
10387                                 break;
10388                         }
10389                 }
10390
10391                 cache = next_block_group(fs_info->tree_root, cache);
10392         }
10393
10394         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
10395         devices = &root->fs_info->fs_devices->alloc_list;
10396         list_for_each_entry(device, devices, dev_alloc_list) {
10397                 ret = btrfs_trim_free_extents(device, range->minlen,
10398                                               &group_trimmed);
10399                 if (ret)
10400                         break;
10401
10402                 trimmed += group_trimmed;
10403         }
10404         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
10405
10406         range->len = trimmed;
10407         return ret;
10408 }
10409
10410 /*
10411  * btrfs_{start,end}_write_no_snapshoting() are similar to
10412  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
10413  * data into the page cache through nocow before the subvolume is snapshoted,
10414  * but flush the data into disk after the snapshot creation, or to prevent
10415  * operations while snapshoting is ongoing and that cause the snapshot to be
10416  * inconsistent (writes followed by expanding truncates for example).
10417  */
10418 void btrfs_end_write_no_snapshoting(struct btrfs_root *root)
10419 {
10420         percpu_counter_dec(&root->subv_writers->counter);
10421         /*
10422          * Make sure counter is updated before we wake up waiters.
10423          */
10424         smp_mb();
10425         if (waitqueue_active(&root->subv_writers->wait))
10426                 wake_up(&root->subv_writers->wait);
10427 }
10428
10429 int btrfs_start_write_no_snapshoting(struct btrfs_root *root)
10430 {
10431         if (atomic_read(&root->will_be_snapshoted))
10432                 return 0;
10433
10434         percpu_counter_inc(&root->subv_writers->counter);
10435         /*
10436          * Make sure counter is updated before we check for snapshot creation.
10437          */
10438         smp_mb();
10439         if (atomic_read(&root->will_be_snapshoted)) {
10440                 btrfs_end_write_no_snapshoting(root);
10441                 return 0;
10442         }
10443         return 1;
10444 }