Pileus Git - ~andy/linux/blob - 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 "ctree.h"
  30 #include "disk-io.h"
  31 #include "print-tree.h"
  32 #include "transaction.h"
  33 #include "volumes.h"
  34 #include "raid56.h"
  35 #include "locking.h"
  36 #include "free-space-cache.h"
  37 #include "math.h"
  38
  39 #undef SCRAMBLE_DELAYED_REFS
  40
  41 /*
  42  * control flags for do_chunk_alloc's force field
  43  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  44  * if we really need one.
  45  *
  46  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  47  * if we have very few chunks already allocated.  This is
  48  * used as part of the clustering code to help make sure
  49  * we have a good pool of storage to cluster in, without
  50  * filling the FS with empty chunks
  51  *
  52  * CHUNK_ALLOC_FORCE means it must try to allocate one
  53  *
  54  */
  55 enum {
  56         CHUNK_ALLOC_NO_FORCE = 0,
  57         CHUNK_ALLOC_LIMITED = 1,
  58         CHUNK_ALLOC_FORCE = 2,
  59 };
  60
  61 /*
  62  * Control how reservations are dealt with.
  63  *
  64  * RESERVE_FREE - freeing a reservation.
  65  * RESERVE_ALLOC - allocating space and we need to update bytes_may_use for
  66  *   ENOSPC accounting
  67  * RESERVE_ALLOC_NO_ACCOUNT - allocating space and we should not update
  68  *   bytes_may_use as the ENOSPC accounting is done elsewhere
  69  */
  70 enum {
  71         RESERVE_FREE = 0,
  72         RESERVE_ALLOC = 1,
  73         RESERVE_ALLOC_NO_ACCOUNT = 2,
  74 };
  75
  76 static int update_block_group(struct btrfs_root *root,
  77                               u64 bytenr, u64 num_bytes, int alloc);
  78 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  79                                 struct btrfs_root *root,
  80                                 u64 bytenr, u64 num_bytes, u64 parent,
  81                                 u64 root_objectid, u64 owner_objectid,
  82                                 u64 owner_offset, int refs_to_drop,
  83                                 struct btrfs_delayed_extent_op *extra_op);
  84 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  85                                     struct extent_buffer *leaf,
  86                                     struct btrfs_extent_item *ei);
  87 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  88                                       struct btrfs_root *root,
  89                                       u64 parent, u64 root_objectid,
  90                                       u64 flags, u64 owner, u64 offset,
  91                                       struct btrfs_key *ins, int ref_mod);
  92 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  93                                      struct btrfs_root *root,
  94                                      u64 parent, u64 root_objectid,
  95                                      u64 flags, struct btrfs_disk_key *key,
  96                                      int level, struct btrfs_key *ins);
  97 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  98                           struct btrfs_root *extent_root, u64 flags,
  99                           int force);
 100 static int find_next_key(struct btrfs_path *path, int level,
 101                          struct btrfs_key *key);
 102 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
 103                             int dump_block_groups);
 104 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
 105                                        u64 num_bytes, int reserve);
 106 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
 107                                u64 num_bytes);
 108 int btrfs_pin_extent(struct btrfs_root *root,
 109                      u64 bytenr, u64 num_bytes, int reserved);
 110
 111 static noinline int
 112 block_group_cache_done(struct btrfs_block_group_cache *cache)
 113 {
 114         smp_mb();
 115         return cache->cached == BTRFS_CACHE_FINISHED ||
 116                 cache->cached == BTRFS_CACHE_ERROR;
 117 }
 118
 119 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 120 {
 121         return (cache->flags & bits) == bits;
 122 }
 123
 124 static void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 125 {
 126         atomic_inc(&cache->count);
 127 }
 128
 129 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 130 {
 131         if (atomic_dec_and_test(&cache->count)) {
 132                 WARN_ON(cache->pinned > 0);
 133                 WARN_ON(cache->reserved > 0);
 134                 kfree(cache->free_space_ctl);
 135                 kfree(cache);
 136         }
 137 }
 138
 139 /*
 140  * this adds the block group to the fs_info rb tree for the block group
 141  * cache
 142  */
 143 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 144                                 struct btrfs_block_group_cache *block_group)
 145 {
 146         struct rb_node **p;
 147         struct rb_node *parent = NULL;
 148         struct btrfs_block_group_cache *cache;
 149
 150         spin_lock(&info->block_group_cache_lock);
 151         p = &info->block_group_cache_tree.rb_node;
 152
 153         while (*p) {
 154                 parent = *p;
 155                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 156                                  cache_node);
 157                 if (block_group->key.objectid < cache->key.objectid) {
 158                         p = &(*p)->rb_left;
 159                 } else if (block_group->key.objectid > cache->key.objectid) {
 160                         p = &(*p)->rb_right;
 161                 } else {
 162                         spin_unlock(&info->block_group_cache_lock);
 163                         return -EEXIST;
 164                 }
 165         }
 166
 167         rb_link_node(&block_group->cache_node, parent, p);
 168         rb_insert_color(&block_group->cache_node,
 169                         &info->block_group_cache_tree);
 170
 171         if (info->first_logical_byte > block_group->key.objectid)
 172                 info->first_logical_byte = block_group->key.objectid;
 173
 174         spin_unlock(&info->block_group_cache_lock);
 175
 176         return 0;
 177 }
 178
 179 /*
 180  * This will return the block group at or after bytenr if contains is 0, else
 181  * it will return the block group that contains the bytenr
 182  */
 183 static struct btrfs_block_group_cache *
 184 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 185                               int contains)
 186 {
 187         struct btrfs_block_group_cache *cache, *ret = NULL;
 188         struct rb_node *n;
 189         u64 end, start;
 190
 191         spin_lock(&info->block_group_cache_lock);
 192         n = info->block_group_cache_tree.rb_node;
 193
 194         while (n) {
 195                 cache = rb_entry(n, struct btrfs_block_group_cache,
 196                                  cache_node);
 197                 end = cache->key.objectid + cache->key.offset - 1;
 198                 start = cache->key.objectid;
 199
 200                 if (bytenr < start) {
 201                         if (!contains && (!ret || start < ret->key.objectid))
 202                                 ret = cache;
 203                         n = n->rb_left;
 204                 } else if (bytenr > start) {
 205                         if (contains && bytenr <= end) {
 206                                 ret = cache;
 207                                 break;
 208                         }
 209                         n = n->rb_right;
 210                 } else {
 211                         ret = cache;
 212                         break;
 213                 }
 214         }
 215         if (ret) {
 216                 btrfs_get_block_group(ret);
 217                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 218                         info->first_logical_byte = ret->key.objectid;
 219         }
 220         spin_unlock(&info->block_group_cache_lock);
 221
 222         return ret;
 223 }
 224
 225 static int add_excluded_extent(struct btrfs_root *root,
 226                                u64 start, u64 num_bytes)
 227 {
 228         u64 end = start + num_bytes - 1;
 229         set_extent_bits(&root->fs_info->freed_extents[0],
 230                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 231         set_extent_bits(&root->fs_info->freed_extents[1],
 232                         start, end, EXTENT_UPTODATE, GFP_NOFS);
 233         return 0;
 234 }
 235
 236 static void free_excluded_extents(struct btrfs_root *root,
 237                                   struct btrfs_block_group_cache *cache)
 238 {
 239         u64 start, end;
 240
 241         start = cache->key.objectid;
 242         end = start + cache->key.offset - 1;
 243
 244         clear_extent_bits(&root->fs_info->freed_extents[0],
 245                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 246         clear_extent_bits(&root->fs_info->freed_extents[1],
 247                           start, end, EXTENT_UPTODATE, GFP_NOFS);
 248 }
 249
 250 static int exclude_super_stripes(struct btrfs_root *root,
 251                                  struct btrfs_block_group_cache *cache)
 252 {
 253         u64 bytenr;
 254         u64 *logical;
 255         int stripe_len;
 256         int i, nr, ret;
 257
 258         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 259                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 260                 cache->bytes_super += stripe_len;
 261                 ret = add_excluded_extent(root, cache->key.objectid,
 262                                           stripe_len);
 263                 if (ret)
 264                         return ret;
 265         }
 266
 267         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 268                 bytenr = btrfs_sb_offset(i);
 269                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 270                                        cache->key.objectid, bytenr,
 271                                        0, &logical, &nr, &stripe_len);
 272                 if (ret)
 273                         return ret;
 274
 275                 while (nr--) {
 276                         u64 start, len;
 277
 278                         if (logical[nr] > cache->key.objectid +
 279                             cache->key.offset)
 280                                 continue;
 281
 282                         if (logical[nr] + stripe_len <= cache->key.objectid)
 283                                 continue;
 284
 285                         start = logical[nr];
 286                         if (start < cache->key.objectid) {
 287                                 start = cache->key.objectid;
 288                                 len = (logical[nr] + stripe_len) - start;
 289                         } else {
 290                                 len = min_t(u64, stripe_len,
 291                                             cache->key.objectid +
 292                                             cache->key.offset - start);
 293                         }
 294
 295                         cache->bytes_super += len;
 296                         ret = add_excluded_extent(root, start, len);
 297                         if (ret) {
 298                                 kfree(logical);
 299                                 return ret;
 300                         }
 301                 }
 302
 303                 kfree(logical);
 304         }
 305         return 0;
 306 }
 307
 308 static struct btrfs_caching_control *
 309 get_caching_control(struct btrfs_block_group_cache *cache)
 310 {
 311         struct btrfs_caching_control *ctl;
 312
 313         spin_lock(&cache->lock);
 314         if (cache->cached != BTRFS_CACHE_STARTED) {
 315                 spin_unlock(&cache->lock);
 316                 return NULL;
 317         }
 318
 319         /* We're loading it the fast way, so we don't have a caching_ctl. */
 320         if (!cache->caching_ctl) {
 321                 spin_unlock(&cache->lock);
 322                 return NULL;
 323         }
 324
 325         ctl = cache->caching_ctl;
 326         atomic_inc(&ctl->count);
 327         spin_unlock(&cache->lock);
 328         return ctl;
 329 }
 330
 331 static void put_caching_control(struct btrfs_caching_control *ctl)
 332 {
 333         if (atomic_dec_and_test(&ctl->count))
 334                 kfree(ctl);
 335 }
 336
 337 /*
 338  * this is only called by cache_block_group, since we could have freed extents
 339  * we need to check the pinned_extents for any extents that can't be used yet
 340  * since their free space will be released as soon as the transaction commits.
 341  */
 342 static u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 343                               struct btrfs_fs_info *info, u64 start, u64 end)
 344 {
 345         u64 extent_start, extent_end, size, total_added = 0;
 346         int ret;
 347
 348         while (start < end) {
 349                 ret = find_first_extent_bit(info->pinned_extents, start,
 350                                             &extent_start, &extent_end,
 351                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 352                                             NULL);
 353                 if (ret)
 354                         break;
 355
 356                 if (extent_start <= start) {
 357                         start = extent_end + 1;
 358                 } else if (extent_start > start && extent_start < end) {
 359                         size = extent_start - start;
 360                         total_added += size;
 361                         ret = btrfs_add_free_space(block_group, start,
 362                                                    size);
 363                         BUG_ON(ret); /* -ENOMEM or logic error */
 364                         start = extent_end + 1;
 365                 } else {
 366                         break;
 367                 }
 368         }
 369
 370         if (start < end) {
 371                 size = end - start;
 372                 total_added += size;
 373                 ret = btrfs_add_free_space(block_group, start, size);
 374                 BUG_ON(ret); /* -ENOMEM or logic error */
 375         }
 376
 377         return total_added;
 378 }
 379
 380 static noinline void caching_thread(struct btrfs_work *work)
 381 {
 382         struct btrfs_block_group_cache *block_group;
 383         struct btrfs_fs_info *fs_info;
 384         struct btrfs_caching_control *caching_ctl;
 385         struct btrfs_root *extent_root;
 386         struct btrfs_path *path;
 387         struct extent_buffer *leaf;
 388         struct btrfs_key key;
 389         u64 total_found = 0;
 390         u64 last = 0;
 391         u32 nritems;
 392         int ret = -ENOMEM;
 393
 394         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 395         block_group = caching_ctl->block_group;
 396         fs_info = block_group->fs_info;
 397         extent_root = fs_info->extent_root;
 398
 399         path = btrfs_alloc_path();
 400         if (!path)
 401                 goto out;
 402
 403         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 404
 405         /*
 406          * We don't want to deadlock with somebody trying to allocate a new
 407          * extent for the extent root while also trying to search the extent
 408          * root to add free space.  So we skip locking and search the commit
 409          * root, since its read-only
 410          */
 411         path->skip_locking = 1;
 412         path->search_commit_root = 1;
 413         path->reada = 1;
 414
 415         key.objectid = last;
 416         key.offset = 0;
 417         key.type = BTRFS_EXTENT_ITEM_KEY;
 418 again:
 419         mutex_lock(&caching_ctl->mutex);
 420         /* need to make sure the commit_root doesn't disappear */
 421         down_read(&fs_info->extent_commit_sem);
 422
 423 next:
 424         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 425         if (ret < 0)
 426                 goto err;
 427
 428         leaf = path->nodes[0];
 429         nritems = btrfs_header_nritems(leaf);
 430
 431         while (1) {
 432                 if (btrfs_fs_closing(fs_info) > 1) {
 433                         last = (u64)-1;
 434                         break;
 435                 }
 436
 437                 if (path->slots[0] < nritems) {
 438                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 439                 } else {
 440                         ret = find_next_key(path, 0, &key);
 441                         if (ret)
 442                                 break;
 443
 444                         if (need_resched()) {
 445                                 caching_ctl->progress = last;
 446                                 btrfs_release_path(path);
 447                                 up_read(&fs_info->extent_commit_sem);
 448                                 mutex_unlock(&caching_ctl->mutex);
 449                                 cond_resched();
 450                                 goto again;
 451                         }
 452
 453                         ret = btrfs_next_leaf(extent_root, path);
 454                         if (ret < 0)
 455                                 goto err;
 456                         if (ret)
 457                                 break;
 458                         leaf = path->nodes[0];
 459                         nritems = btrfs_header_nritems(leaf);
 460                         continue;
 461                 }
 462
 463                 if (key.objectid < last) {
 464                         key.objectid = last;
 465                         key.offset = 0;
 466                         key.type = BTRFS_EXTENT_ITEM_KEY;
 467
 468                         caching_ctl->progress = last;
 469                         btrfs_release_path(path);
 470                         goto next;
 471                 }
 472
 473                 if (key.objectid < block_group->key.objectid) {
 474                         path->slots[0]++;
 475                         continue;
 476                 }
 477
 478                 if (key.objectid >= block_group->key.objectid +
 479                     block_group->key.offset)
 480                         break;
 481
 482                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 483                     key.type == BTRFS_METADATA_ITEM_KEY) {
 484                         total_found += add_new_free_space(block_group,
 485                                                           fs_info, last,
 486                                                           key.objectid);
 487                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 488                                 last = key.objectid +
 489                                         fs_info->tree_root->leafsize;
 490                         else
 491                                 last = key.objectid + key.offset;
 492
 493                         if (total_found > (1024 * 1024 * 2)) {
 494                                 total_found = 0;
 495                                 wake_up(&caching_ctl->wait);
 496                         }
 497                 }
 498                 path->slots[0]++;
 499         }
 500         ret = 0;
 501
 502         total_found += add_new_free_space(block_group, fs_info, last,
 503                                           block_group->key.objectid +
 504                                           block_group->key.offset);
 505         caching_ctl->progress = (u64)-1;
 506
 507         spin_lock(&block_group->lock);
 508         block_group->caching_ctl = NULL;
 509         block_group->cached = BTRFS_CACHE_FINISHED;
 510         spin_unlock(&block_group->lock);
 511
 512 err:
 513         btrfs_free_path(path);
 514         up_read(&fs_info->extent_commit_sem);
 515
 516         free_excluded_extents(extent_root, block_group);
 517
 518         mutex_unlock(&caching_ctl->mutex);
 519 out:
 520         if (ret) {
 521                 spin_lock(&block_group->lock);
 522                 block_group->caching_ctl = NULL;
 523                 block_group->cached = BTRFS_CACHE_ERROR;
 524                 spin_unlock(&block_group->lock);
 525         }
 526         wake_up(&caching_ctl->wait);
 527
 528         put_caching_control(caching_ctl);
 529         btrfs_put_block_group(block_group);
 530 }
 531
 532 static int cache_block_group(struct btrfs_block_group_cache *cache,
 533                              int load_cache_only)
 534 {
 535         DEFINE_WAIT(wait);
 536         struct btrfs_fs_info *fs_info = cache->fs_info;
 537         struct btrfs_caching_control *caching_ctl;
 538         int ret = 0;
 539
 540         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 541         if (!caching_ctl)
 542                 return -ENOMEM;
 543
 544         INIT_LIST_HEAD(&caching_ctl->list);
 545         mutex_init(&caching_ctl->mutex);
 546         init_waitqueue_head(&caching_ctl->wait);
 547         caching_ctl->block_group = cache;
 548         caching_ctl->progress = cache->key.objectid;
 549         atomic_set(&caching_ctl->count, 1);
 550         caching_ctl->work.func = caching_thread;
 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                 ret = load_free_space_cache(fs_info, cache);
 592
 593                 spin_lock(&cache->lock);
 594                 if (ret == 1) {
 595                         cache->caching_ctl = NULL;
 596                         cache->cached = BTRFS_CACHE_FINISHED;
 597                         cache->last_byte_to_unpin = (u64)-1;
 598                 } else {
 599                         if (load_cache_only) {
 600                                 cache->caching_ctl = NULL;
 601                                 cache->cached = BTRFS_CACHE_NO;
 602                         } else {
 603                                 cache->cached = BTRFS_CACHE_STARTED;
 604                         }
 605                 }
 606                 spin_unlock(&cache->lock);
 607                 wake_up(&caching_ctl->wait);
 608                 if (ret == 1) {
 609                         put_caching_control(caching_ctl);
 610                         free_excluded_extents(fs_info->extent_root, cache);
 611                         return 0;
 612                 }
 613         } else {
 614                 /*
 615                  * We are not going to do the fast caching, set cached to the
 616                  * appropriate value and wakeup any waiters.
 617                  */
 618                 spin_lock(&cache->lock);
 619                 if (load_cache_only) {
 620                         cache->caching_ctl = NULL;
 621                         cache->cached = BTRFS_CACHE_NO;
 622                 } else {
 623                         cache->cached = BTRFS_CACHE_STARTED;
 624                 }
 625                 spin_unlock(&cache->lock);
 626                 wake_up(&caching_ctl->wait);
 627         }
 628
 629         if (load_cache_only) {
 630                 put_caching_control(caching_ctl);
 631                 return 0;
 632         }
 633
 634         down_write(&fs_info->extent_commit_sem);
 635         atomic_inc(&caching_ctl->count);
 636         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 637         up_write(&fs_info->extent_commit_sem);
 638
 639         btrfs_get_block_group(cache);
 640
 641         btrfs_queue_worker(&fs_info->caching_workers, &caching_ctl->work);
 642
 643         return ret;
 644 }
 645
 646 /*
 647  * return the block group that starts at or after bytenr
 648  */
 649 static struct btrfs_block_group_cache *
 650 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 651 {
 652         struct btrfs_block_group_cache *cache;
 653
 654         cache = block_group_cache_tree_search(info, bytenr, 0);
 655
 656         return cache;
 657 }
 658
 659 /*
 660  * return the block group that contains the given bytenr
 661  */
 662 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 663                                                  struct btrfs_fs_info *info,
 664                                                  u64 bytenr)
 665 {
 666         struct btrfs_block_group_cache *cache;
 667
 668         cache = block_group_cache_tree_search(info, bytenr, 1);
 669
 670         return cache;
 671 }
 672
 673 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 674                                                   u64 flags)
 675 {
 676         struct list_head *head = &info->space_info;
 677         struct btrfs_space_info *found;
 678
 679         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 680
 681         rcu_read_lock();
 682         list_for_each_entry_rcu(found, head, list) {
 683                 if (found->flags & flags) {
 684                         rcu_read_unlock();
 685                         return found;
 686                 }
 687         }
 688         rcu_read_unlock();
 689         return NULL;
 690 }
 691
 692 /*
 693  * after adding space to the filesystem, we need to clear the full flags
 694  * on all the space infos.
 695  */
 696 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 697 {
 698         struct list_head *head = &info->space_info;
 699         struct btrfs_space_info *found;
 700
 701         rcu_read_lock();
 702         list_for_each_entry_rcu(found, head, list)
 703                 found->full = 0;
 704         rcu_read_unlock();
 705 }
 706
 707 /* simple helper to search for an existing extent at a given offset */
 708 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 709 {
 710         int ret;
 711         struct btrfs_key key;
 712         struct btrfs_path *path;
 713
 714         path = btrfs_alloc_path();
 715         if (!path)
 716                 return -ENOMEM;
 717
 718         key.objectid = start;
 719         key.offset = len;
 720         key.type = BTRFS_EXTENT_ITEM_KEY;
 721         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 722                                 0, 0);
 723         if (ret > 0) {
 724                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
 725                 if (key.objectid == start &&
 726                     key.type == BTRFS_METADATA_ITEM_KEY)
 727                         ret = 0;
 728         }
 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->leafsize;
 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 again:
 784         ret = btrfs_search_slot(trans, root->fs_info->extent_root,
 785                                 &key, path, 0, 0);
 786         if (ret < 0)
 787                 goto out_free;
 788
 789         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 790                 if (path->slots[0]) {
 791                         path->slots[0]--;
 792                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 793                                               path->slots[0]);
 794                         if (key.objectid == bytenr &&
 795                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 796                             key.offset == root->leafsize)
 797                                 ret = 0;
 798                 }
 799                 if (ret) {
 800                         key.objectid = bytenr;
 801                         key.type = BTRFS_EXTENT_ITEM_KEY;
 802                         key.offset = root->leafsize;
 803                         btrfs_release_path(path);
 804                         goto again;
 805                 }
 806         }
 807
 808         if (ret == 0) {
 809                 leaf = path->nodes[0];
 810                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 811                 if (item_size >= sizeof(*ei)) {
 812                         ei = btrfs_item_ptr(leaf, path->slots[0],
 813                                             struct btrfs_extent_item);
 814                         num_refs = btrfs_extent_refs(leaf, ei);
 815                         extent_flags = btrfs_extent_flags(leaf, ei);
 816                 } else {
 817 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 818                         struct btrfs_extent_item_v0 *ei0;
 819                         BUG_ON(item_size != sizeof(*ei0));
 820                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 821                                              struct btrfs_extent_item_v0);
 822                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 823                         /* FIXME: this isn't correct for data */
 824                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 825 #else
 826                         BUG();
 827 #endif
 828                 }
 829                 BUG_ON(num_refs == 0);
 830         } else {
 831                 num_refs = 0;
 832                 extent_flags = 0;
 833                 ret = 0;
 834         }
 835
 836         if (!trans)
 837                 goto out;
 838
 839         delayed_refs = &trans->transaction->delayed_refs;
 840         spin_lock(&delayed_refs->lock);
 841         head = btrfs_find_delayed_ref_head(trans, bytenr);
 842         if (head) {
 843                 if (!mutex_trylock(&head->mutex)) {
 844                         atomic_inc(&head->node.refs);
 845                         spin_unlock(&delayed_refs->lock);
 846
 847                         btrfs_release_path(path);
 848
 849                         /*
 850                          * Mutex was contended, block until it's released and try
 851                          * again
 852                          */
 853                         mutex_lock(&head->mutex);
 854                         mutex_unlock(&head->mutex);
 855                         btrfs_put_delayed_ref(&head->node);
 856                         goto search_again;
 857                 }
 858                 if (head->extent_op && head->extent_op->update_flags)
 859                         extent_flags |= head->extent_op->flags_to_set;
 860                 else
 861                         BUG_ON(num_refs == 0);
 862
 863                 num_refs += head->node.ref_mod;
 864                 mutex_unlock(&head->mutex);
 865         }
 866         spin_unlock(&delayed_refs->lock);
 867 out:
 868         WARN_ON(num_refs == 0);
 869         if (refs)
 870                 *refs = num_refs;
 871         if (flags)
 872                 *flags = extent_flags;
 873 out_free:
 874         btrfs_free_path(path);
 875         return ret;
 876 }
 877
 878 /*
 879  * Back reference rules.  Back refs have three main goals:
 880  *
 881  * 1) differentiate between all holders of references to an extent so that
 882  *    when a reference is dropped we can make sure it was a valid reference
 883  *    before freeing the extent.
 884  *
 885  * 2) Provide enough information to quickly find the holders of an extent
 886  *    if we notice a given block is corrupted or bad.
 887  *
 888  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 889  *    maintenance.  This is actually the same as #2, but with a slightly
 890  *    different use case.
 891  *
 892  * There are two kinds of back refs. The implicit back refs is optimized
 893  * for pointers in non-shared tree blocks. For a given pointer in a block,
 894  * back refs of this kind provide information about the block's owner tree
 895  * and the pointer's key. These information allow us to find the block by
 896  * b-tree searching. The full back refs is for pointers in tree blocks not
 897  * referenced by their owner trees. The location of tree block is recorded
 898  * in the back refs. Actually the full back refs is generic, and can be
 899  * used in all cases the implicit back refs is used. The major shortcoming
 900  * of the full back refs is its overhead. Every time a tree block gets
 901  * COWed, we have to update back refs entry for all pointers in it.
 902  *
 903  * For a newly allocated tree block, we use implicit back refs for
 904  * pointers in it. This means most tree related operations only involve
 905  * implicit back refs. For a tree block created in old transaction, the
 906  * only way to drop a reference to it is COW it. So we can detect the
 907  * event that tree block loses its owner tree's reference and do the
 908  * back refs conversion.
 909  *
 910  * When a tree block is COW'd through a tree, there are four cases:
 911  *
 912  * The reference count of the block is one and the tree is the block's
 913  * owner tree. Nothing to do in this case.
 914  *
 915  * The reference count of the block is one and the tree is not the
 916  * block's owner tree. In this case, full back refs is used for pointers
 917  * in the block. Remove these full back refs, add implicit back refs for
 918  * every pointers in the new block.
 919  *
 920  * The reference count of the block is greater than one and the tree is
 921  * the block's owner tree. In this case, implicit back refs is used for
 922  * pointers in the block. Add full back refs for every pointers in the
 923  * block, increase lower level extents' reference counts. The original
 924  * implicit back refs are entailed to the new block.
 925  *
 926  * The reference count of the block is greater than one and the tree is
 927  * not the block's owner tree. Add implicit back refs for every pointer in
 928  * the new block, increase lower level extents' reference count.
 929  *
 930  * Back Reference Key composing:
 931  *
 932  * The key objectid corresponds to the first byte in the extent,
 933  * The key type is used to differentiate between types of back refs.
 934  * There are different meanings of the key offset for different types
 935  * of back refs.
 936  *
 937  * File extents can be referenced by:
 938  *
 939  * - multiple snapshots, subvolumes, or different generations in one subvol
 940  * - different files inside a single subvolume
 941  * - different offsets inside a file (bookend extents in file.c)
 942  *
 943  * The extent ref structure for the implicit back refs has fields for:
 944  *
 945  * - Objectid of the subvolume root
 946  * - objectid of the file holding the reference
 947  * - original offset in the file
 948  * - how many bookend extents
 949  *
 950  * The key offset for the implicit back refs is hash of the first
 951  * three fields.
 952  *
 953  * The extent ref structure for the full back refs has field for:
 954  *
 955  * - number of pointers in the tree leaf
 956  *
 957  * The key offset for the implicit back refs is the first byte of
 958  * the tree leaf
 959  *
 960  * When a file extent is allocated, The implicit back refs is used.
 961  * the fields are filled in:
 962  *
 963  *     (root_key.objectid, inode objectid, offset in file, 1)
 964  *
 965  * When a file extent is removed file truncation, we find the
 966  * corresponding implicit back refs and check the following fields:
 967  *
 968  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 969  *
 970  * Btree extents can be referenced by:
 971  *
 972  * - Different subvolumes
 973  *
 974  * Both the implicit back refs and the full back refs for tree blocks
 975  * only consist of key. The key offset for the implicit back refs is
 976  * objectid of block's owner tree. The key offset for the full back refs
 977  * is the first byte of parent block.
 978  *
 979  * When implicit back refs is used, information about the lowest key and
 980  * level of the tree block are required. These information are stored in
 981  * tree block info structure.
 982  */
 983
 984 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 985 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
 986                                   struct btrfs_root *root,
 987                                   struct btrfs_path *path,
 988                                   u64 owner, u32 extra_size)
 989 {
 990         struct btrfs_extent_item *item;
 991         struct btrfs_extent_item_v0 *ei0;
 992         struct btrfs_extent_ref_v0 *ref0;
 993         struct btrfs_tree_block_info *bi;
 994         struct extent_buffer *leaf;
 995         struct btrfs_key key;
 996         struct btrfs_key found_key;
 997         u32 new_size = sizeof(*item);
 998         u64 refs;
 999         int ret;
1000
1001         leaf = path->nodes[0];
1002         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1003
1004         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1005         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1006                              struct btrfs_extent_item_v0);
1007         refs = btrfs_extent_refs_v0(leaf, ei0);
1008
1009         if (owner == (u64)-1) {
1010                 while (1) {
1011                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1012                                 ret = btrfs_next_leaf(root, path);
1013                                 if (ret < 0)
1014                                         return ret;
1015                                 BUG_ON(ret > 0); /* Corruption */
1016                                 leaf = path->nodes[0];
1017                         }
1018                         btrfs_item_key_to_cpu(leaf, &found_key,
1019                                               path->slots[0]);
1020                         BUG_ON(key.objectid != found_key.objectid);
1021                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1022                                 path->slots[0]++;
1023                                 continue;
1024                         }
1025                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1026                                               struct btrfs_extent_ref_v0);
1027                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1028                         break;
1029                 }
1030         }
1031         btrfs_release_path(path);
1032
1033         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1034                 new_size += sizeof(*bi);
1035
1036         new_size -= sizeof(*ei0);
1037         ret = btrfs_search_slot(trans, root, &key, path,
1038                                 new_size + extra_size, 1);
1039         if (ret < 0)
1040                 return ret;
1041         BUG_ON(ret); /* Corruption */
1042
1043         btrfs_extend_item(root, path, new_size);
1044
1045         leaf = path->nodes[0];
1046         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1047         btrfs_set_extent_refs(leaf, item, refs);
1048         /* FIXME: get real generation */
1049         btrfs_set_extent_generation(leaf, item, 0);
1050         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1051                 btrfs_set_extent_flags(leaf, item,
1052                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1053                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1054                 bi = (struct btrfs_tree_block_info *)(item + 1);
1055                 /* FIXME: get first key of the block */
1056                 memset_extent_buffer(leaf, 0, (unsigned long)bi, sizeof(*bi));
1057                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1058         } else {
1059                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1060         }
1061         btrfs_mark_buffer_dirty(leaf);
1062         return 0;
1063 }
1064 #endif
1065
1066 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1067 {
1068         u32 high_crc = ~(u32)0;
1069         u32 low_crc = ~(u32)0;
1070         __le64 lenum;
1071
1072         lenum = cpu_to_le64(root_objectid);
1073         high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
1074         lenum = cpu_to_le64(owner);
1075         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1076         lenum = cpu_to_le64(offset);
1077         low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
1078
1079         return ((u64)high_crc << 31) ^ (u64)low_crc;
1080 }
1081
1082 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1083                                      struct btrfs_extent_data_ref *ref)
1084 {
1085         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1086                                     btrfs_extent_data_ref_objectid(leaf, ref),
1087                                     btrfs_extent_data_ref_offset(leaf, ref));
1088 }
1089
1090 static int match_extent_data_ref(struct extent_buffer *leaf,
1091                                  struct btrfs_extent_data_ref *ref,
1092                                  u64 root_objectid, u64 owner, u64 offset)
1093 {
1094         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1095             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1096             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1097                 return 0;
1098         return 1;
1099 }
1100
1101 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1102                                            struct btrfs_root *root,
1103                                            struct btrfs_path *path,
1104                                            u64 bytenr, u64 parent,
1105                                            u64 root_objectid,
1106                                            u64 owner, u64 offset)
1107 {
1108         struct btrfs_key key;
1109         struct btrfs_extent_data_ref *ref;
1110         struct extent_buffer *leaf;
1111         u32 nritems;
1112         int ret;
1113         int recow;
1114         int err = -ENOENT;
1115
1116         key.objectid = bytenr;
1117         if (parent) {
1118                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1119                 key.offset = parent;
1120         } else {
1121                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1122                 key.offset = hash_extent_data_ref(root_objectid,
1123                                                   owner, offset);
1124         }
1125 again:
1126         recow = 0;
1127         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1128         if (ret < 0) {
1129                 err = ret;
1130                 goto fail;
1131         }
1132
1133         if (parent) {
1134                 if (!ret)
1135                         return 0;
1136 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1137                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1138                 btrfs_release_path(path);
1139                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1140                 if (ret < 0) {
1141                         err = ret;
1142                         goto fail;
1143                 }
1144                 if (!ret)
1145                         return 0;
1146 #endif
1147                 goto fail;
1148         }
1149
1150         leaf = path->nodes[0];
1151         nritems = btrfs_header_nritems(leaf);
1152         while (1) {
1153                 if (path->slots[0] >= nritems) {
1154                         ret = btrfs_next_leaf(root, path);
1155                         if (ret < 0)
1156                                 err = ret;
1157                         if (ret)
1158                                 goto fail;
1159
1160                         leaf = path->nodes[0];
1161                         nritems = btrfs_header_nritems(leaf);
1162                         recow = 1;
1163                 }
1164
1165                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1166                 if (key.objectid != bytenr ||
1167                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1168                         goto fail;
1169
1170                 ref = btrfs_item_ptr(leaf, path->slots[0],
1171                                      struct btrfs_extent_data_ref);
1172
1173                 if (match_extent_data_ref(leaf, ref, root_objectid,
1174                                           owner, offset)) {
1175                         if (recow) {
1176                                 btrfs_release_path(path);
1177                                 goto again;
1178                         }
1179                         err = 0;
1180                         break;
1181                 }
1182                 path->slots[0]++;
1183         }
1184 fail:
1185         return err;
1186 }
1187
1188 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1189                                            struct btrfs_root *root,
1190                                            struct btrfs_path *path,
1191                                            u64 bytenr, u64 parent,
1192                                            u64 root_objectid, u64 owner,
1193                                            u64 offset, int refs_to_add)
1194 {
1195         struct btrfs_key key;
1196         struct extent_buffer *leaf;
1197         u32 size;
1198         u32 num_refs;
1199         int ret;
1200
1201         key.objectid = bytenr;
1202         if (parent) {
1203                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1204                 key.offset = parent;
1205                 size = sizeof(struct btrfs_shared_data_ref);
1206         } else {
1207                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1208                 key.offset = hash_extent_data_ref(root_objectid,
1209                                                   owner, offset);
1210                 size = sizeof(struct btrfs_extent_data_ref);
1211         }
1212
1213         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1214         if (ret && ret != -EEXIST)
1215                 goto fail;
1216
1217         leaf = path->nodes[0];
1218         if (parent) {
1219                 struct btrfs_shared_data_ref *ref;
1220                 ref = btrfs_item_ptr(leaf, path->slots[0],
1221                                      struct btrfs_shared_data_ref);
1222                 if (ret == 0) {
1223                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1224                 } else {
1225                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1226                         num_refs += refs_to_add;
1227                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1228                 }
1229         } else {
1230                 struct btrfs_extent_data_ref *ref;
1231                 while (ret == -EEXIST) {
1232                         ref = btrfs_item_ptr(leaf, path->slots[0],
1233                                              struct btrfs_extent_data_ref);
1234                         if (match_extent_data_ref(leaf, ref, root_objectid,
1235                                                   owner, offset))
1236                                 break;
1237                         btrfs_release_path(path);
1238                         key.offset++;
1239                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1240                                                       size);
1241                         if (ret && ret != -EEXIST)
1242                                 goto fail;
1243
1244                         leaf = path->nodes[0];
1245                 }
1246                 ref = btrfs_item_ptr(leaf, path->slots[0],
1247                                      struct btrfs_extent_data_ref);
1248                 if (ret == 0) {
1249                         btrfs_set_extent_data_ref_root(leaf, ref,
1250                                                        root_objectid);
1251                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1252                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1253                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1254                 } else {
1255                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1256                         num_refs += refs_to_add;
1257                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1258                 }
1259         }
1260         btrfs_mark_buffer_dirty(leaf);
1261         ret = 0;
1262 fail:
1263         btrfs_release_path(path);
1264         return ret;
1265 }
1266
1267 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1268                                            struct btrfs_root *root,
1269                                            struct btrfs_path *path,
1270                                            int refs_to_drop)
1271 {
1272         struct btrfs_key key;
1273         struct btrfs_extent_data_ref *ref1 = NULL;
1274         struct btrfs_shared_data_ref *ref2 = NULL;
1275         struct extent_buffer *leaf;
1276         u32 num_refs = 0;
1277         int ret = 0;
1278
1279         leaf = path->nodes[0];
1280         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1281
1282         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1283                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1284                                       struct btrfs_extent_data_ref);
1285                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1286         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1287                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1288                                       struct btrfs_shared_data_ref);
1289                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1290 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1291         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1292                 struct btrfs_extent_ref_v0 *ref0;
1293                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1294                                       struct btrfs_extent_ref_v0);
1295                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1296 #endif
1297         } else {
1298                 BUG();
1299         }
1300
1301         BUG_ON(num_refs < refs_to_drop);
1302         num_refs -= refs_to_drop;
1303
1304         if (num_refs == 0) {
1305                 ret = btrfs_del_item(trans, root, path);
1306         } else {
1307                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1308                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1309                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1310                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1311 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1312                 else {
1313                         struct btrfs_extent_ref_v0 *ref0;
1314                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1315                                         struct btrfs_extent_ref_v0);
1316                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1317                 }
1318 #endif
1319                 btrfs_mark_buffer_dirty(leaf);
1320         }
1321         return ret;
1322 }
1323
1324 static noinline u32 extent_data_ref_count(struct btrfs_root *root,
1325                                           struct btrfs_path *path,
1326                                           struct btrfs_extent_inline_ref *iref)
1327 {
1328         struct btrfs_key key;
1329         struct extent_buffer *leaf;
1330         struct btrfs_extent_data_ref *ref1;
1331         struct btrfs_shared_data_ref *ref2;
1332         u32 num_refs = 0;
1333
1334         leaf = path->nodes[0];
1335         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1336         if (iref) {
1337                 if (btrfs_extent_inline_ref_type(leaf, iref) ==
1338                     BTRFS_EXTENT_DATA_REF_KEY) {
1339                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1340                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1341                 } else {
1342                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1343                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1344                 }
1345         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1346                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1347                                       struct btrfs_extent_data_ref);
1348                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1349         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1350                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1351                                       struct btrfs_shared_data_ref);
1352                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1353 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1354         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1355                 struct btrfs_extent_ref_v0 *ref0;
1356                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1357                                       struct btrfs_extent_ref_v0);
1358                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1359 #endif
1360         } else {
1361                 WARN_ON(1);
1362         }
1363         return num_refs;
1364 }
1365
1366 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1367                                           struct btrfs_root *root,
1368                                           struct btrfs_path *path,
1369                                           u64 bytenr, u64 parent,
1370                                           u64 root_objectid)
1371 {
1372         struct btrfs_key key;
1373         int ret;
1374
1375         key.objectid = bytenr;
1376         if (parent) {
1377                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1378                 key.offset = parent;
1379         } else {
1380                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1381                 key.offset = root_objectid;
1382         }
1383
1384         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1385         if (ret > 0)
1386                 ret = -ENOENT;
1387 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1388         if (ret == -ENOENT && parent) {
1389                 btrfs_release_path(path);
1390                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1391                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1392                 if (ret > 0)
1393                         ret = -ENOENT;
1394         }
1395 #endif
1396         return ret;
1397 }
1398
1399 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1400                                           struct btrfs_root *root,
1401                                           struct btrfs_path *path,
1402                                           u64 bytenr, u64 parent,
1403                                           u64 root_objectid)
1404 {
1405         struct btrfs_key key;
1406         int ret;
1407
1408         key.objectid = bytenr;
1409         if (parent) {
1410                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1411                 key.offset = parent;
1412         } else {
1413                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1414                 key.offset = root_objectid;
1415         }
1416
1417         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
1418         btrfs_release_path(path);
1419         return ret;
1420 }
1421
1422 static inline int extent_ref_type(u64 parent, u64 owner)
1423 {
1424         int type;
1425         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1426                 if (parent > 0)
1427                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1428                 else
1429                         type = BTRFS_TREE_BLOCK_REF_KEY;
1430         } else {
1431                 if (parent > 0)
1432                         type = BTRFS_SHARED_DATA_REF_KEY;
1433                 else
1434                         type = BTRFS_EXTENT_DATA_REF_KEY;
1435         }
1436         return type;
1437 }
1438
1439 static int find_next_key(struct btrfs_path *path, int level,
1440                          struct btrfs_key *key)
1441
1442 {
1443         for (; level < BTRFS_MAX_LEVEL; level++) {
1444                 if (!path->nodes[level])
1445                         break;
1446                 if (path->slots[level] + 1 >=
1447                     btrfs_header_nritems(path->nodes[level]))
1448                         continue;
1449                 if (level == 0)
1450                         btrfs_item_key_to_cpu(path->nodes[level], key,
1451                                               path->slots[level] + 1);
1452                 else
1453                         btrfs_node_key_to_cpu(path->nodes[level], key,
1454                                               path->slots[level] + 1);
1455                 return 0;
1456         }
1457         return 1;
1458 }
1459
1460 /*
1461  * look for inline back ref. if back ref is found, *ref_ret is set
1462  * to the address of inline back ref, and 0 is returned.
1463  *
1464  * if back ref isn't found, *ref_ret is set to the address where it
1465  * should be inserted, and -ENOENT is returned.
1466  *
1467  * if insert is true and there are too many inline back refs, the path
1468  * points to the extent item, and -EAGAIN is returned.
1469  *
1470  * NOTE: inline back refs are ordered in the same way that back ref
1471  *       items in the tree are ordered.
1472  */
1473 static noinline_for_stack
1474 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1475                                  struct btrfs_root *root,
1476                                  struct btrfs_path *path,
1477                                  struct btrfs_extent_inline_ref **ref_ret,
1478                                  u64 bytenr, u64 num_bytes,
1479                                  u64 parent, u64 root_objectid,
1480                                  u64 owner, u64 offset, int insert)
1481 {
1482         struct btrfs_key key;
1483         struct extent_buffer *leaf;
1484         struct btrfs_extent_item *ei;
1485         struct btrfs_extent_inline_ref *iref;
1486         u64 flags;
1487         u64 item_size;
1488         unsigned long ptr;
1489         unsigned long end;
1490         int extra_size;
1491         int type;
1492         int want;
1493         int ret;
1494         int err = 0;
1495         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
1496                                                  SKINNY_METADATA);
1497
1498         key.objectid = bytenr;
1499         key.type = BTRFS_EXTENT_ITEM_KEY;
1500         key.offset = num_bytes;
1501
1502         want = extent_ref_type(parent, owner);
1503         if (insert) {
1504                 extra_size = btrfs_extent_inline_ref_size(want);
1505                 path->keep_locks = 1;
1506         } else
1507                 extra_size = -1;
1508
1509         /*
1510          * Owner is our parent level, so we can just add one to get the level
1511          * for the block we are interested in.
1512          */
1513         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1514                 key.type = BTRFS_METADATA_ITEM_KEY;
1515                 key.offset = owner;
1516         }
1517
1518 again:
1519         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1520         if (ret < 0) {
1521                 err = ret;
1522                 goto out;
1523         }
1524
1525         /*
1526          * We may be a newly converted file system which still has the old fat
1527          * extent entries for metadata, so try and see if we have one of those.
1528          */
1529         if (ret > 0 && skinny_metadata) {
1530                 skinny_metadata = false;
1531                 if (path->slots[0]) {
1532                         path->slots[0]--;
1533                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1534                                               path->slots[0]);
1535                         if (key.objectid == bytenr &&
1536                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1537                             key.offset == num_bytes)
1538                                 ret = 0;
1539                 }
1540                 if (ret) {
1541                         key.type = BTRFS_EXTENT_ITEM_KEY;
1542                         key.offset = num_bytes;
1543                         btrfs_release_path(path);
1544                         goto again;
1545                 }
1546         }
1547
1548         if (ret && !insert) {
1549                 err = -ENOENT;
1550                 goto out;
1551         } else if (WARN_ON(ret)) {
1552                 err = -EIO;
1553                 goto out;
1554         }
1555
1556         leaf = path->nodes[0];
1557         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1558 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1559         if (item_size < sizeof(*ei)) {
1560                 if (!insert) {
1561                         err = -ENOENT;
1562                         goto out;
1563                 }
1564                 ret = convert_extent_item_v0(trans, root, path, owner,
1565                                              extra_size);
1566                 if (ret < 0) {
1567                         err = ret;
1568                         goto out;
1569                 }
1570                 leaf = path->nodes[0];
1571                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1572         }
1573 #endif
1574         BUG_ON(item_size < sizeof(*ei));
1575
1576         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1577         flags = btrfs_extent_flags(leaf, ei);
1578
1579         ptr = (unsigned long)(ei + 1);
1580         end = (unsigned long)ei + item_size;
1581
1582         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1583                 ptr += sizeof(struct btrfs_tree_block_info);
1584                 BUG_ON(ptr > end);
1585         }
1586
1587         err = -ENOENT;
1588         while (1) {
1589                 if (ptr >= end) {
1590                         WARN_ON(ptr > end);
1591                         break;
1592                 }
1593                 iref = (struct btrfs_extent_inline_ref *)ptr;
1594                 type = btrfs_extent_inline_ref_type(leaf, iref);
1595                 if (want < type)
1596                         break;
1597                 if (want > type) {
1598                         ptr += btrfs_extent_inline_ref_size(type);
1599                         continue;
1600                 }
1601
1602                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1603                         struct btrfs_extent_data_ref *dref;
1604                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1605                         if (match_extent_data_ref(leaf, dref, root_objectid,
1606                                                   owner, offset)) {
1607                                 err = 0;
1608                                 break;
1609                         }
1610                         if (hash_extent_data_ref_item(leaf, dref) <
1611                             hash_extent_data_ref(root_objectid, owner, offset))
1612                                 break;
1613                 } else {
1614                         u64 ref_offset;
1615                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1616                         if (parent > 0) {
1617                                 if (parent == ref_offset) {
1618                                         err = 0;
1619                                         break;
1620                                 }
1621                                 if (ref_offset < parent)
1622                                         break;
1623                         } else {
1624                                 if (root_objectid == ref_offset) {
1625                                         err = 0;
1626                                         break;
1627                                 }
1628                                 if (ref_offset < root_objectid)
1629                                         break;
1630                         }
1631                 }
1632                 ptr += btrfs_extent_inline_ref_size(type);
1633         }
1634         if (err == -ENOENT && insert) {
1635                 if (item_size + extra_size >=
1636                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1637                         err = -EAGAIN;
1638                         goto out;
1639                 }
1640                 /*
1641                  * To add new inline back ref, we have to make sure
1642                  * there is no corresponding back ref item.
1643                  * For simplicity, we just do not add new inline back
1644                  * ref if there is any kind of item for this block
1645                  */
1646                 if (find_next_key(path, 0, &key) == 0 &&
1647                     key.objectid == bytenr &&
1648                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1649                         err = -EAGAIN;
1650                         goto out;
1651                 }
1652         }
1653         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1654 out:
1655         if (insert) {
1656                 path->keep_locks = 0;
1657                 btrfs_unlock_up_safe(path, 1);
1658         }
1659         return err;
1660 }
1661
1662 /*
1663  * helper to add new inline back ref
1664  */
1665 static noinline_for_stack
1666 void setup_inline_extent_backref(struct btrfs_root *root,
1667                                  struct btrfs_path *path,
1668                                  struct btrfs_extent_inline_ref *iref,
1669                                  u64 parent, u64 root_objectid,
1670                                  u64 owner, u64 offset, int refs_to_add,
1671                                  struct btrfs_delayed_extent_op *extent_op)
1672 {
1673         struct extent_buffer *leaf;
1674         struct btrfs_extent_item *ei;
1675         unsigned long ptr;
1676         unsigned long end;
1677         unsigned long item_offset;
1678         u64 refs;
1679         int size;
1680         int type;
1681
1682         leaf = path->nodes[0];
1683         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1684         item_offset = (unsigned long)iref - (unsigned long)ei;
1685
1686         type = extent_ref_type(parent, owner);
1687         size = btrfs_extent_inline_ref_size(type);
1688
1689         btrfs_extend_item(root, path, size);
1690
1691         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1692         refs = btrfs_extent_refs(leaf, ei);
1693         refs += refs_to_add;
1694         btrfs_set_extent_refs(leaf, ei, refs);
1695         if (extent_op)
1696                 __run_delayed_extent_op(extent_op, leaf, ei);
1697
1698         ptr = (unsigned long)ei + item_offset;
1699         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1700         if (ptr < end - size)
1701                 memmove_extent_buffer(leaf, ptr + size, ptr,
1702                                       end - size - ptr);
1703
1704         iref = (struct btrfs_extent_inline_ref *)ptr;
1705         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1706         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1707                 struct btrfs_extent_data_ref *dref;
1708                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1709                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1710                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1711                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1712                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1713         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1714                 struct btrfs_shared_data_ref *sref;
1715                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1716                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1717                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1718         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1719                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1720         } else {
1721                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1722         }
1723         btrfs_mark_buffer_dirty(leaf);
1724 }
1725
1726 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1727                                  struct btrfs_root *root,
1728                                  struct btrfs_path *path,
1729                                  struct btrfs_extent_inline_ref **ref_ret,
1730                                  u64 bytenr, u64 num_bytes, u64 parent,
1731                                  u64 root_objectid, u64 owner, u64 offset)
1732 {
1733         int ret;
1734
1735         ret = lookup_inline_extent_backref(trans, root, path, ref_ret,
1736                                            bytenr, num_bytes, parent,
1737                                            root_objectid, owner, offset, 0);
1738         if (ret != -ENOENT)
1739                 return ret;
1740
1741         btrfs_release_path(path);
1742         *ref_ret = NULL;
1743
1744         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1745                 ret = lookup_tree_block_ref(trans, root, path, bytenr, parent,
1746                                             root_objectid);
1747         } else {
1748                 ret = lookup_extent_data_ref(trans, root, path, bytenr, parent,
1749                                              root_objectid, owner, offset);
1750         }
1751         return ret;
1752 }
1753
1754 /*
1755  * helper to update/remove inline back ref
1756  */
1757 static noinline_for_stack
1758 void update_inline_extent_backref(struct btrfs_root *root,
1759                                   struct btrfs_path *path,
1760                                   struct btrfs_extent_inline_ref *iref,
1761                                   int refs_to_mod,
1762                                   struct btrfs_delayed_extent_op *extent_op)
1763 {
1764         struct extent_buffer *leaf;
1765         struct btrfs_extent_item *ei;
1766         struct btrfs_extent_data_ref *dref = NULL;
1767         struct btrfs_shared_data_ref *sref = NULL;
1768         unsigned long ptr;
1769         unsigned long end;
1770         u32 item_size;
1771         int size;
1772         int type;
1773         u64 refs;
1774
1775         leaf = path->nodes[0];
1776         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1777         refs = btrfs_extent_refs(leaf, ei);
1778         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1779         refs += refs_to_mod;
1780         btrfs_set_extent_refs(leaf, ei, refs);
1781         if (extent_op)
1782                 __run_delayed_extent_op(extent_op, leaf, ei);
1783
1784         type = btrfs_extent_inline_ref_type(leaf, iref);
1785
1786         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1787                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1788                 refs = btrfs_extent_data_ref_count(leaf, dref);
1789         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1790                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1791                 refs = btrfs_shared_data_ref_count(leaf, sref);
1792         } else {
1793                 refs = 1;
1794                 BUG_ON(refs_to_mod != -1);
1795         }
1796
1797         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1798         refs += refs_to_mod;
1799
1800         if (refs > 0) {
1801                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1802                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1803                 else
1804                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1805         } else {
1806                 size =  btrfs_extent_inline_ref_size(type);
1807                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1808                 ptr = (unsigned long)iref;
1809                 end = (unsigned long)ei + item_size;
1810                 if (ptr + size < end)
1811                         memmove_extent_buffer(leaf, ptr, ptr + size,
1812                                               end - ptr - size);
1813                 item_size -= size;
1814                 btrfs_truncate_item(root, path, item_size, 1);
1815         }
1816         btrfs_mark_buffer_dirty(leaf);
1817 }
1818
1819 static noinline_for_stack
1820 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1821                                  struct btrfs_root *root,
1822                                  struct btrfs_path *path,
1823                                  u64 bytenr, u64 num_bytes, u64 parent,
1824                                  u64 root_objectid, u64 owner,
1825                                  u64 offset, int refs_to_add,
1826                                  struct btrfs_delayed_extent_op *extent_op)
1827 {
1828         struct btrfs_extent_inline_ref *iref;
1829         int ret;
1830
1831         ret = lookup_inline_extent_backref(trans, root, path, &iref,
1832                                            bytenr, num_bytes, parent,
1833                                            root_objectid, owner, offset, 1);
1834         if (ret == 0) {
1835                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
1836                 update_inline_extent_backref(root, path, iref,
1837                                              refs_to_add, extent_op);
1838         } else if (ret == -ENOENT) {
1839                 setup_inline_extent_backref(root, path, iref, parent,
1840                                             root_objectid, owner, offset,
1841                                             refs_to_add, extent_op);
1842                 ret = 0;
1843         }
1844         return ret;
1845 }
1846
1847 static int insert_extent_backref(struct btrfs_trans_handle *trans,
1848                                  struct btrfs_root *root,
1849                                  struct btrfs_path *path,
1850                                  u64 bytenr, u64 parent, u64 root_objectid,
1851                                  u64 owner, u64 offset, int refs_to_add)
1852 {
1853         int ret;
1854         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1855                 BUG_ON(refs_to_add != 1);
1856                 ret = insert_tree_block_ref(trans, root, path, bytenr,
1857                                             parent, root_objectid);
1858         } else {
1859                 ret = insert_extent_data_ref(trans, root, path, bytenr,
1860                                              parent, root_objectid,
1861                                              owner, offset, refs_to_add);
1862         }
1863         return ret;
1864 }
1865
1866 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1867                                  struct btrfs_root *root,
1868                                  struct btrfs_path *path,
1869                                  struct btrfs_extent_inline_ref *iref,
1870                                  int refs_to_drop, int is_data)
1871 {
1872         int ret = 0;
1873
1874         BUG_ON(!is_data && refs_to_drop != 1);
1875         if (iref) {
1876                 update_inline_extent_backref(root, path, iref,
1877                                              -refs_to_drop, NULL);
1878         } else if (is_data) {
1879                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1880         } else {
1881                 ret = btrfs_del_item(trans, root, path);
1882         }
1883         return ret;
1884 }
1885
1886 static int btrfs_issue_discard(struct block_device *bdev,
1887                                 u64 start, u64 len)
1888 {
1889         return blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_NOFS, 0);
1890 }
1891
1892 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
1893                                 u64 num_bytes, u64 *actual_bytes)
1894 {
1895         int ret;
1896         u64 discarded_bytes = 0;
1897         struct btrfs_bio *bbio = NULL;
1898
1899
1900         /* Tell the block device(s) that the sectors can be discarded */
1901         ret = btrfs_map_block(root->fs_info, REQ_DISCARD,
1902                               bytenr, &num_bytes, &bbio, 0);
1903         /* Error condition is -ENOMEM */
1904         if (!ret) {
1905                 struct btrfs_bio_stripe *stripe = bbio->stripes;
1906                 int i;
1907
1908
1909                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
1910                         if (!stripe->dev->can_discard)
1911                                 continue;
1912
1913                         ret = btrfs_issue_discard(stripe->dev->bdev,
1914                                                   stripe->physical,
1915                                                   stripe->length);
1916                         if (!ret)
1917                                 discarded_bytes += stripe->length;
1918                         else if (ret != -EOPNOTSUPP)
1919                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
1920
1921                         /*
1922                          * Just in case we get back EOPNOTSUPP for some reason,
1923                          * just ignore the return value so we don't screw up
1924                          * people calling discard_extent.
1925                          */
1926                         ret = 0;
1927                 }
1928                 kfree(bbio);
1929         }
1930
1931         if (actual_bytes)
1932                 *actual_bytes = discarded_bytes;
1933
1934
1935         if (ret == -EOPNOTSUPP)
1936                 ret = 0;
1937         return ret;
1938 }
1939
1940 /* Can return -ENOMEM */
1941 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1942                          struct btrfs_root *root,
1943                          u64 bytenr, u64 num_bytes, u64 parent,
1944                          u64 root_objectid, u64 owner, u64 offset, int for_cow)
1945 {
1946         int ret;
1947         struct btrfs_fs_info *fs_info = root->fs_info;
1948
1949         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
1950                root_objectid == BTRFS_TREE_LOG_OBJECTID);
1951
1952         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1953                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
1954                                         num_bytes,
1955                                         parent, root_objectid, (int)owner,
1956                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1957         } else {
1958                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
1959                                         num_bytes,
1960                                         parent, root_objectid, owner, offset,
1961                                         BTRFS_ADD_DELAYED_REF, NULL, for_cow);
1962         }
1963         return ret;
1964 }
1965
1966 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1967                                   struct btrfs_root *root,
1968                                   u64 bytenr, u64 num_bytes,
1969                                   u64 parent, u64 root_objectid,
1970                                   u64 owner, u64 offset, int refs_to_add,
1971                                   struct btrfs_delayed_extent_op *extent_op)
1972 {
1973         struct btrfs_path *path;
1974         struct extent_buffer *leaf;
1975         struct btrfs_extent_item *item;
1976         u64 refs;
1977         int ret;
1978
1979         path = btrfs_alloc_path();
1980         if (!path)
1981                 return -ENOMEM;
1982
1983         path->reada = 1;
1984         path->leave_spinning = 1;
1985         /* this will setup the path even if it fails to insert the back ref */
1986         ret = insert_inline_extent_backref(trans, root->fs_info->extent_root,
1987                                            path, bytenr, num_bytes, parent,
1988                                            root_objectid, owner, offset,
1989                                            refs_to_add, extent_op);
1990         if (ret != -EAGAIN)
1991                 goto out;
1992
1993         leaf = path->nodes[0];
1994         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1995         refs = btrfs_extent_refs(leaf, item);
1996         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1997         if (extent_op)
1998                 __run_delayed_extent_op(extent_op, leaf, item);
1999
2000         btrfs_mark_buffer_dirty(leaf);
2001         btrfs_release_path(path);
2002
2003         path->reada = 1;
2004         path->leave_spinning = 1;
2005
2006         /* now insert the actual backref */
2007         ret = insert_extent_backref(trans, root->fs_info->extent_root,
2008                                     path, bytenr, parent, root_objectid,
2009                                     owner, offset, refs_to_add);
2010         if (ret)
2011                 btrfs_abort_transaction(trans, root, ret);
2012 out:
2013         btrfs_free_path(path);
2014         return ret;
2015 }
2016
2017 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2018                                 struct btrfs_root *root,
2019                                 struct btrfs_delayed_ref_node *node,
2020                                 struct btrfs_delayed_extent_op *extent_op,
2021                                 int insert_reserved)
2022 {
2023         int ret = 0;
2024         struct btrfs_delayed_data_ref *ref;
2025         struct btrfs_key ins;
2026         u64 parent = 0;
2027         u64 ref_root = 0;
2028         u64 flags = 0;
2029
2030         ins.objectid = node->bytenr;
2031         ins.offset = node->num_bytes;
2032         ins.type = BTRFS_EXTENT_ITEM_KEY;
2033
2034         ref = btrfs_delayed_node_to_data_ref(node);
2035         trace_run_delayed_data_ref(node, ref, node->action);
2036
2037         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2038                 parent = ref->parent;
2039         else
2040                 ref_root = ref->root;
2041
2042         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2043                 if (extent_op)
2044                         flags |= extent_op->flags_to_set;
2045                 ret = alloc_reserved_file_extent(trans, root,
2046                                                  parent, ref_root, flags,
2047                                                  ref->objectid, ref->offset,
2048                                                  &ins, node->ref_mod);
2049         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2050                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2051                                              node->num_bytes, parent,
2052                                              ref_root, ref->objectid,
2053                                              ref->offset, node->ref_mod,
2054                                              extent_op);
2055         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2056                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2057                                           node->num_bytes, parent,
2058                                           ref_root, ref->objectid,
2059                                           ref->offset, node->ref_mod,
2060                                           extent_op);
2061         } else {
2062                 BUG();
2063         }
2064         return ret;
2065 }
2066
2067 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2068                                     struct extent_buffer *leaf,
2069                                     struct btrfs_extent_item *ei)
2070 {
2071         u64 flags = btrfs_extent_flags(leaf, ei);
2072         if (extent_op->update_flags) {
2073                 flags |= extent_op->flags_to_set;
2074                 btrfs_set_extent_flags(leaf, ei, flags);
2075         }
2076
2077         if (extent_op->update_key) {
2078                 struct btrfs_tree_block_info *bi;
2079                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2080                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2081                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2082         }
2083 }
2084
2085 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2086                                  struct btrfs_root *root,
2087                                  struct btrfs_delayed_ref_node *node,
2088                                  struct btrfs_delayed_extent_op *extent_op)
2089 {
2090         struct btrfs_key key;
2091         struct btrfs_path *path;
2092         struct btrfs_extent_item *ei;
2093         struct extent_buffer *leaf;
2094         u32 item_size;
2095         int ret;
2096         int err = 0;
2097         int metadata = !extent_op->is_data;
2098
2099         if (trans->aborted)
2100                 return 0;
2101
2102         if (metadata && !btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2103                 metadata = 0;
2104
2105         path = btrfs_alloc_path();
2106         if (!path)
2107                 return -ENOMEM;
2108
2109         key.objectid = node->bytenr;
2110
2111         if (metadata) {
2112                 key.type = BTRFS_METADATA_ITEM_KEY;
2113                 key.offset = extent_op->level;
2114         } else {
2115                 key.type = BTRFS_EXTENT_ITEM_KEY;
2116                 key.offset = node->num_bytes;
2117         }
2118
2119 again:
2120         path->reada = 1;
2121         path->leave_spinning = 1;
2122         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key,
2123                                 path, 0, 1);
2124         if (ret < 0) {
2125                 err = ret;
2126                 goto out;
2127         }
2128         if (ret > 0) {
2129                 if (metadata) {
2130                         if (path->slots[0] > 0) {
2131                                 path->slots[0]--;
2132                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2133                                                       path->slots[0]);
2134                                 if (key.objectid == node->bytenr &&
2135                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2136                                     key.offset == node->num_bytes)
2137                                         ret = 0;
2138                         }
2139                         if (ret > 0) {
2140                                 btrfs_release_path(path);
2141                                 metadata = 0;
2142
2143                                 key.objectid = node->bytenr;
2144                                 key.offset = node->num_bytes;
2145                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2146                                 goto again;
2147                         }
2148                 } else {
2149                         err = -EIO;
2150                         goto out;
2151                 }
2152         }
2153
2154         leaf = path->nodes[0];
2155         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2156 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2157         if (item_size < sizeof(*ei)) {
2158                 ret = convert_extent_item_v0(trans, root->fs_info->extent_root,
2159                                              path, (u64)-1, 0);
2160                 if (ret < 0) {
2161                         err = ret;
2162                         goto out;
2163                 }
2164                 leaf = path->nodes[0];
2165                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2166         }
2167 #endif
2168         BUG_ON(item_size < sizeof(*ei));
2169         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2170         __run_delayed_extent_op(extent_op, leaf, ei);
2171
2172         btrfs_mark_buffer_dirty(leaf);
2173 out:
2174         btrfs_free_path(path);
2175         return err;
2176 }
2177
2178 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2179                                 struct btrfs_root *root,
2180                                 struct btrfs_delayed_ref_node *node,
2181                                 struct btrfs_delayed_extent_op *extent_op,
2182                                 int insert_reserved)
2183 {
2184         int ret = 0;
2185         struct btrfs_delayed_tree_ref *ref;
2186         struct btrfs_key ins;
2187         u64 parent = 0;
2188         u64 ref_root = 0;
2189         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
2190                                                  SKINNY_METADATA);
2191
2192         ref = btrfs_delayed_node_to_tree_ref(node);
2193         trace_run_delayed_tree_ref(node, ref, node->action);
2194
2195         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2196                 parent = ref->parent;
2197         else
2198                 ref_root = ref->root;
2199
2200         ins.objectid = node->bytenr;
2201         if (skinny_metadata) {
2202                 ins.offset = ref->level;
2203                 ins.type = BTRFS_METADATA_ITEM_KEY;
2204         } else {
2205                 ins.offset = node->num_bytes;
2206                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2207         }
2208
2209         BUG_ON(node->ref_mod != 1);
2210         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2211                 BUG_ON(!extent_op || !extent_op->update_flags);
2212                 ret = alloc_reserved_tree_block(trans, root,
2213                                                 parent, ref_root,
2214                                                 extent_op->flags_to_set,
2215                                                 &extent_op->key,
2216                                                 ref->level, &ins);
2217         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2218                 ret = __btrfs_inc_extent_ref(trans, root, node->bytenr,
2219                                              node->num_bytes, parent, ref_root,
2220                                              ref->level, 0, 1, extent_op);
2221         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2222                 ret = __btrfs_free_extent(trans, root, node->bytenr,
2223                                           node->num_bytes, parent, ref_root,
2224                                           ref->level, 0, 1, extent_op);
2225         } else {
2226                 BUG();
2227         }
2228         return ret;
2229 }
2230
2231 /* helper function to actually process a single delayed ref entry */
2232 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2233                                struct btrfs_root *root,
2234                                struct btrfs_delayed_ref_node *node,
2235                                struct btrfs_delayed_extent_op *extent_op,
2236                                int insert_reserved)
2237 {
2238         int ret = 0;
2239
2240         if (trans->aborted) {
2241                 if (insert_reserved)
2242                         btrfs_pin_extent(root, node->bytenr,
2243                                          node->num_bytes, 1);
2244                 return 0;
2245         }
2246
2247         if (btrfs_delayed_ref_is_head(node)) {
2248                 struct btrfs_delayed_ref_head *head;
2249                 /*
2250                  * we've hit the end of the chain and we were supposed
2251                  * to insert this extent into the tree.  But, it got
2252                  * deleted before we ever needed to insert it, so all
2253                  * we have to do is clean up the accounting
2254                  */
2255                 BUG_ON(extent_op);
2256                 head = btrfs_delayed_node_to_head(node);
2257                 trace_run_delayed_ref_head(node, head, node->action);
2258
2259                 if (insert_reserved) {
2260                         btrfs_pin_extent(root, node->bytenr,
2261                                          node->num_bytes, 1);
2262                         if (head->is_data) {
2263                                 ret = btrfs_del_csums(trans, root,
2264                                                       node->bytenr,
2265                                                       node->num_bytes);
2266                         }
2267                 }
2268                 return ret;
2269         }
2270
2271         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2272             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2273                 ret = run_delayed_tree_ref(trans, root, node, extent_op,
2274                                            insert_reserved);
2275         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2276                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2277                 ret = run_delayed_data_ref(trans, root, node, extent_op,
2278                                            insert_reserved);
2279         else
2280                 BUG();
2281         return ret;
2282 }
2283
2284 static noinline struct btrfs_delayed_ref_node *
2285 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2286 {
2287         struct rb_node *node;
2288         struct btrfs_delayed_ref_node *ref;
2289         int action = BTRFS_ADD_DELAYED_REF;
2290 again:
2291         /*
2292          * select delayed ref of type BTRFS_ADD_DELAYED_REF first.
2293          * this prevents ref count from going down to zero when
2294          * there still are pending delayed ref.
2295          */
2296         node = rb_prev(&head->node.rb_node);
2297         while (1) {
2298                 if (!node)
2299                         break;
2300                 ref = rb_entry(node, struct btrfs_delayed_ref_node,
2301                                 rb_node);
2302                 if (ref->bytenr != head->node.bytenr)
2303                         break;
2304                 if (ref->action == action)
2305                         return ref;
2306                 node = rb_prev(node);
2307         }
2308         if (action == BTRFS_ADD_DELAYED_REF) {
2309                 action = BTRFS_DROP_DELAYED_REF;
2310                 goto again;
2311         }
2312         return NULL;
2313 }
2314
2315 /*
2316  * Returns 0 on success or if called with an already aborted transaction.
2317  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2318  */
2319 static noinline int run_clustered_refs(struct btrfs_trans_handle *trans,
2320                                        struct btrfs_root *root,
2321                                        struct list_head *cluster)
2322 {
2323         struct btrfs_delayed_ref_root *delayed_refs;
2324         struct btrfs_delayed_ref_node *ref;
2325         struct btrfs_delayed_ref_head *locked_ref = NULL;
2326         struct btrfs_delayed_extent_op *extent_op;
2327         struct btrfs_fs_info *fs_info = root->fs_info;
2328         int ret;
2329         int count = 0;
2330         int must_insert_reserved = 0;
2331
2332         delayed_refs = &trans->transaction->delayed_refs;
2333         while (1) {
2334                 if (!locked_ref) {
2335                         /* pick a new head ref from the cluster list */
2336                         if (list_empty(cluster))
2337                                 break;
2338
2339                         locked_ref = list_entry(cluster->next,
2340                                      struct btrfs_delayed_ref_head, cluster);
2341
2342                         /* grab the lock that says we are going to process
2343                          * all the refs for this head */
2344                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2345
2346                         /*
2347                          * we may have dropped the spin lock to get the head
2348                          * mutex lock, and that might have given someone else
2349                          * time to free the head.  If that's true, it has been
2350                          * removed from our list and we can move on.
2351                          */
2352                         if (ret == -EAGAIN) {
2353                                 locked_ref = NULL;
2354                                 count++;
2355                                 continue;
2356                         }
2357                 }
2358
2359                 /*
2360                  * We need to try and merge add/drops of the same ref since we
2361                  * can run into issues with relocate dropping the implicit ref
2362                  * and then it being added back again before the drop can
2363                  * finish.  If we merged anything we need to re-loop so we can
2364                  * get a good ref.
2365                  */
2366                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2367                                          locked_ref);
2368
2369                 /*
2370                  * locked_ref is the head node, so we have to go one
2371                  * node back for any delayed ref updates
2372                  */
2373                 ref = select_delayed_ref(locked_ref);
2374
2375                 if (ref && ref->seq &&
2376                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2377                         /*
2378                          * there are still refs with lower seq numbers in the
2379                          * process of being added. Don't run this ref yet.
2380                          */
2381                         list_del_init(&locked_ref->cluster);
2382                         btrfs_delayed_ref_unlock(locked_ref);
2383                         locked_ref = NULL;
2384                         delayed_refs->num_heads_ready++;
2385                         spin_unlock(&delayed_refs->lock);
2386                         cond_resched();
2387                         spin_lock(&delayed_refs->lock);
2388                         continue;
2389                 }
2390
2391                 /*
2392                  * record the must insert reserved flag before we
2393                  * drop the spin lock.
2394                  */
2395                 must_insert_reserved = locked_ref->must_insert_reserved;
2396                 locked_ref->must_insert_reserved = 0;
2397
2398                 extent_op = locked_ref->extent_op;
2399                 locked_ref->extent_op = NULL;
2400
2401                 if (!ref) {
2402                         /* All delayed refs have been processed, Go ahead
2403                          * and send the head node to run_one_delayed_ref,
2404                          * so that any accounting fixes can happen
2405                          */
2406                         ref = &locked_ref->node;
2407
2408                         if (extent_op && must_insert_reserved) {
2409                                 btrfs_free_delayed_extent_op(extent_op);
2410                                 extent_op = NULL;
2411                         }
2412
2413                         if (extent_op) {
2414                                 spin_unlock(&delayed_refs->lock);
2415
2416                                 ret = run_delayed_extent_op(trans, root,
2417                                                             ref, extent_op);
2418                                 btrfs_free_delayed_extent_op(extent_op);
2419
2420                                 if (ret) {
2421                                         /*
2422                                          * Need to reset must_insert_reserved if
2423                                          * there was an error so the abort stuff
2424                                          * can cleanup the reserved space
2425                                          * properly.
2426                                          */
2427                                         if (must_insert_reserved)
2428                                                 locked_ref->must_insert_reserved = 1;
2429                                         btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
2430                                         spin_lock(&delayed_refs->lock);
2431                                         btrfs_delayed_ref_unlock(locked_ref);
2432                                         return ret;
2433                                 }
2434
2435                                 goto next;
2436                         }
2437                 }
2438
2439                 ref->in_tree = 0;
2440                 rb_erase(&ref->rb_node, &delayed_refs->root);
2441                 delayed_refs->num_entries--;
2442                 if (!btrfs_delayed_ref_is_head(ref)) {
2443                         /*
2444                          * when we play the delayed ref, also correct the
2445                          * ref_mod on head
2446                          */
2447                         switch (ref->action) {
2448                         case BTRFS_ADD_DELAYED_REF:
2449                         case BTRFS_ADD_DELAYED_EXTENT:
2450                                 locked_ref->node.ref_mod -= ref->ref_mod;
2451                                 break;
2452                         case BTRFS_DROP_DELAYED_REF:
2453                                 locked_ref->node.ref_mod += ref->ref_mod;
2454                                 break;
2455                         default:
2456                                 WARN_ON(1);
2457                         }
2458                 } else {
2459                         list_del_init(&locked_ref->cluster);
2460                 }
2461                 spin_unlock(&delayed_refs->lock);
2462
2463                 ret = run_one_delayed_ref(trans, root, ref, extent_op,
2464                                           must_insert_reserved);
2465
2466                 btrfs_free_delayed_extent_op(extent_op);
2467                 if (ret) {
2468                         btrfs_delayed_ref_unlock(locked_ref);
2469                         btrfs_put_delayed_ref(ref);
2470                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d", ret);
2471                         spin_lock(&delayed_refs->lock);
2472                         return ret;
2473                 }
2474
2475                 /*
2476                  * If this node is a head, that means all the refs in this head
2477                  * have been dealt with, and we will pick the next head to deal
2478                  * with, so we must unlock the head and drop it from the cluster
2479                  * list before we release it.
2480                  */
2481                 if (btrfs_delayed_ref_is_head(ref)) {
2482                         btrfs_delayed_ref_unlock(locked_ref);
2483                         locked_ref = NULL;
2484                 }
2485                 btrfs_put_delayed_ref(ref);
2486                 count++;
2487 next:
2488                 cond_resched();
2489                 spin_lock(&delayed_refs->lock);
2490         }
2491         return count;
2492 }
2493
2494 #ifdef SCRAMBLE_DELAYED_REFS
2495 /*
2496  * Normally delayed refs get processed in ascending bytenr order. This
2497  * correlates in most cases to the order added. To expose dependencies on this
2498  * order, we start to process the tree in the middle instead of the beginning
2499  */
2500 static u64 find_middle(struct rb_root *root)
2501 {
2502         struct rb_node *n = root->rb_node;
2503         struct btrfs_delayed_ref_node *entry;
2504         int alt = 1;
2505         u64 middle;
2506         u64 first = 0, last = 0;
2507
2508         n = rb_first(root);
2509         if (n) {
2510                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2511                 first = entry->bytenr;
2512         }
2513         n = rb_last(root);
2514         if (n) {
2515                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2516                 last = entry->bytenr;
2517         }
2518         n = root->rb_node;
2519
2520         while (n) {
2521                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2522                 WARN_ON(!entry->in_tree);
2523
2524                 middle = entry->bytenr;
2525
2526                 if (alt)
2527                         n = n->rb_left;
2528                 else
2529                         n = n->rb_right;
2530
2531                 alt = 1 - alt;
2532         }
2533         return middle;
2534 }
2535 #endif
2536
2537 int btrfs_delayed_refs_qgroup_accounting(struct btrfs_trans_handle *trans,
2538                                          struct btrfs_fs_info *fs_info)
2539 {
2540         struct qgroup_update *qgroup_update;
2541         int ret = 0;
2542
2543         if (list_empty(&trans->qgroup_ref_list) !=
2544             !trans->delayed_ref_elem.seq) {
2545                 /* list without seq or seq without list */
2546                 btrfs_err(fs_info,
2547                         "qgroup accounting update error, list is%s empty, seq is %#x.%x",
2548                         list_empty(&trans->qgroup_ref_list) ? "" : " not",
2549                         (u32)(trans->delayed_ref_elem.seq >> 32),
2550                         (u32)trans->delayed_ref_elem.seq);
2551                 BUG();
2552         }
2553
2554         if (!trans->delayed_ref_elem.seq)
2555                 return 0;
2556
2557         while (!list_empty(&trans->qgroup_ref_list)) {
2558                 qgroup_update = list_first_entry(&trans->qgroup_ref_list,
2559                                                  struct qgroup_update, list);
2560                 list_del(&qgroup_update->list);
2561                 if (!ret)
2562                         ret = btrfs_qgroup_account_ref(
2563                                         trans, fs_info, qgroup_update->node,
2564                                         qgroup_update->extent_op);
2565                 kfree(qgroup_update);
2566         }
2567
2568         btrfs_put_tree_mod_seq(fs_info, &trans->delayed_ref_elem);
2569
2570         return ret;
2571 }
2572
2573 static int refs_newer(struct btrfs_delayed_ref_root *delayed_refs, int seq,
2574                       int count)
2575 {
2576         int val = atomic_read(&delayed_refs->ref_seq);
2577
2578         if (val < seq || val >= seq + count)
2579                 return 1;
2580         return 0;
2581 }
2582
2583 static inline u64 heads_to_leaves(struct btrfs_root *root, u64 heads)
2584 {
2585         u64 num_bytes;
2586
2587         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2588                              sizeof(struct btrfs_extent_inline_ref));
2589         if (!btrfs_fs_incompat(root->fs_info, SKINNY_METADATA))
2590                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2591
2592         /*
2593          * We don't ever fill up leaves all the way so multiply by 2 just to be
2594          * closer to what we're really going to want to ouse.
2595          */
2596         return div64_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(root));
2597 }
2598
2599 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2600                                        struct btrfs_root *root)
2601 {
2602         struct btrfs_block_rsv *global_rsv;
2603         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2604         u64 num_bytes;
2605         int ret = 0;
2606
2607         num_bytes = btrfs_calc_trans_metadata_size(root, 1);
2608         num_heads = heads_to_leaves(root, num_heads);
2609         if (num_heads > 1)
2610                 num_bytes += (num_heads - 1) * root->leafsize;
2611         num_bytes <<= 1;
2612         global_rsv = &root->fs_info->global_block_rsv;
2613
2614         /*
2615          * If we can't allocate any more chunks lets make sure we have _lots_ of
2616          * wiggle room since running delayed refs can create more delayed refs.
2617          */
2618         if (global_rsv->space_info->full)
2619                 num_bytes <<= 1;
2620
2621         spin_lock(&global_rsv->lock);
2622         if (global_rsv->reserved <= num_bytes)
2623                 ret = 1;
2624         spin_unlock(&global_rsv->lock);
2625         return ret;
2626 }
2627
2628 /*
2629  * this starts processing the delayed reference count updates and
2630  * extent insertions we have queued up so far.  count can be
2631  * 0, which means to process everything in the tree at the start
2632  * of the run (but not newly added entries), or it can be some target
2633  * number you'd like to process.
2634  *
2635  * Returns 0 on success or if called with an aborted transaction
2636  * Returns <0 on error and aborts the transaction
2637  */
2638 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2639                            struct btrfs_root *root, unsigned long count)
2640 {
2641         struct rb_node *node;
2642         struct btrfs_delayed_ref_root *delayed_refs;
2643         struct btrfs_delayed_ref_node *ref;
2644         struct list_head cluster;
2645         int ret;
2646         u64 delayed_start;
2647         int run_all = count == (unsigned long)-1;
2648         int run_most = 0;
2649         int loops;
2650
2651         /* We'll clean this up in btrfs_cleanup_transaction */
2652         if (trans->aborted)
2653                 return 0;
2654
2655         if (root == root->fs_info->extent_root)
2656                 root = root->fs_info->tree_root;
2657
2658         btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
2659
2660         delayed_refs = &trans->transaction->delayed_refs;
2661         INIT_LIST_HEAD(&cluster);
2662         if (count == 0) {
2663                 count = delayed_refs->num_entries * 2;
2664                 run_most = 1;
2665         }
2666
2667         if (!run_all && !run_most) {
2668                 int old;
2669                 int seq = atomic_read(&delayed_refs->ref_seq);
2670
2671 progress:
2672                 old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2673                 if (old) {
2674                         DEFINE_WAIT(__wait);
2675                         if (delayed_refs->flushing ||
2676                             !btrfs_should_throttle_delayed_refs(trans, root))
2677                                 return 0;
2678
2679                         prepare_to_wait(&delayed_refs->wait, &__wait,
2680                                         TASK_UNINTERRUPTIBLE);
2681
2682                         old = atomic_cmpxchg(&delayed_refs->procs_running_refs, 0, 1);
2683                         if (old) {
2684                                 schedule();
2685                                 finish_wait(&delayed_refs->wait, &__wait);
2686
2687                                 if (!refs_newer(delayed_refs, seq, 256))
2688                                         goto progress;
2689                                 else
2690                                         return 0;
2691                         } else {
2692                                 finish_wait(&delayed_refs->wait, &__wait);
2693                                 goto again;
2694                         }
2695                 }
2696
2697         } else {
2698                 atomic_inc(&delayed_refs->procs_running_refs);
2699         }
2700
2701 again:
2702         loops = 0;
2703         spin_lock(&delayed_refs->lock);
2704
2705 #ifdef SCRAMBLE_DELAYED_REFS
2706         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2707 #endif
2708
2709         while (1) {
2710                 if (!(run_all || run_most) &&
2711                     !btrfs_should_throttle_delayed_refs(trans, root))
2712                         break;
2713
2714                 /*
2715                  * go find something we can process in the rbtree.  We start at
2716                  * the beginning of the tree, and then build a cluster
2717                  * of refs to process starting at the first one we are able to
2718                  * lock
2719                  */
2720                 delayed_start = delayed_refs->run_delayed_start;
2721                 ret = btrfs_find_ref_cluster(trans, &cluster,
2722                                              delayed_refs->run_delayed_start);
2723                 if (ret)
2724                         break;
2725
2726                 ret = run_clustered_refs(trans, root, &cluster);
2727                 if (ret < 0) {
2728                         btrfs_release_ref_cluster(&cluster);
2729                         spin_unlock(&delayed_refs->lock);
2730                         btrfs_abort_transaction(trans, root, ret);
2731                         atomic_dec(&delayed_refs->procs_running_refs);
2732                         wake_up(&delayed_refs->wait);
2733                         return ret;
2734                 }
2735
2736                 atomic_add(ret, &delayed_refs->ref_seq);
2737
2738                 count -= min_t(unsigned long, ret, count);
2739
2740                 if (count == 0)
2741                         break;
2742
2743                 if (delayed_start >= delayed_refs->run_delayed_start) {
2744                         if (loops == 0) {
2745                                 /*
2746                                  * btrfs_find_ref_cluster looped. let's do one
2747                                  * more cycle. if we don't run any delayed ref
2748                                  * during that cycle (because we can't because
2749                                  * all of them are blocked), bail out.
2750                                  */
2751                                 loops = 1;
2752                         } else {
2753                                 /*
2754                                  * no runnable refs left, stop trying
2755                                  */
2756                                 BUG_ON(run_all);
2757                                 break;
2758                         }
2759                 }
2760                 if (ret) {
2761                         /* refs were run, let's reset staleness detection */
2762                         loops = 0;
2763                 }
2764         }
2765
2766         if (run_all) {
2767                 if (!list_empty(&trans->new_bgs)) {
2768                         spin_unlock(&delayed_refs->lock);
2769                         btrfs_create_pending_block_groups(trans, root);
2770                         spin_lock(&delayed_refs->lock);
2771                 }
2772
2773                 node = rb_first(&delayed_refs->root);
2774                 if (!node)
2775                         goto out;
2776                 count = (unsigned long)-1;
2777
2778                 while (node) {
2779                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
2780                                        rb_node);
2781                         if (btrfs_delayed_ref_is_head(ref)) {
2782                                 struct btrfs_delayed_ref_head *head;
2783
2784                                 head = btrfs_delayed_node_to_head(ref);
2785                                 atomic_inc(&ref->refs);
2786
2787                                 spin_unlock(&delayed_refs->lock);
2788                                 /*
2789                                  * Mutex was contended, block until it's
2790                                  * released and try again
2791                                  */
2792                                 mutex_lock(&head->mutex);
2793                                 mutex_unlock(&head->mutex);
2794
2795                                 btrfs_put_delayed_ref(ref);
2796                                 cond_resched();
2797                                 goto again;
2798                         }
2799                         node = rb_next(node);
2800                 }
2801                 spin_unlock(&delayed_refs->lock);
2802                 schedule_timeout(1);
2803                 goto again;
2804         }
2805 out:
2806         atomic_dec(&delayed_refs->procs_running_refs);
2807         smp_mb();
2808         if (waitqueue_active(&delayed_refs->wait))
2809                 wake_up(&delayed_refs->wait);
2810
2811         spin_unlock(&delayed_refs->lock);
2812         assert_qgroups_uptodate(trans);
2813         return 0;
2814 }
2815
2816 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2817                                 struct btrfs_root *root,
2818                                 u64 bytenr, u64 num_bytes, u64 flags,
2819                                 int level, int is_data)
2820 {
2821         struct btrfs_delayed_extent_op *extent_op;
2822         int ret;
2823
2824         extent_op = btrfs_alloc_delayed_extent_op();
2825         if (!extent_op)
2826                 return -ENOMEM;
2827
2828         extent_op->flags_to_set = flags;
2829         extent_op->update_flags = 1;
2830         extent_op->update_key = 0;
2831         extent_op->is_data = is_data ? 1 : 0;
2832         extent_op->level = level;
2833
2834         ret = btrfs_add_delayed_extent_op(root->fs_info, trans, bytenr,
2835                                           num_bytes, extent_op);
2836         if (ret)
2837                 btrfs_free_delayed_extent_op(extent_op);
2838         return ret;
2839 }
2840
2841 static noinline int check_delayed_ref(struct btrfs_trans_handle *trans,
2842                                       struct btrfs_root *root,
2843                                       struct btrfs_path *path,
2844                                       u64 objectid, u64 offset, u64 bytenr)
2845 {
2846         struct btrfs_delayed_ref_head *head;
2847         struct btrfs_delayed_ref_node *ref;
2848         struct btrfs_delayed_data_ref *data_ref;
2849         struct btrfs_delayed_ref_root *delayed_refs;
2850         struct rb_node *node;
2851         int ret = 0;
2852
2853         ret = -ENOENT;
2854         delayed_refs = &trans->transaction->delayed_refs;
2855         spin_lock(&delayed_refs->lock);
2856         head = btrfs_find_delayed_ref_head(trans, bytenr);
2857         if (!head)
2858                 goto out;
2859
2860         if (!mutex_trylock(&head->mutex)) {
2861                 atomic_inc(&head->node.refs);
2862                 spin_unlock(&delayed_refs->lock);
2863
2864                 btrfs_release_path(path);
2865
2866                 /*
2867                  * Mutex was contended, block until it's released and let
2868                  * caller try again
2869                  */
2870                 mutex_lock(&head->mutex);
2871                 mutex_unlock(&head->mutex);
2872                 btrfs_put_delayed_ref(&head->node);
2873                 return -EAGAIN;
2874         }
2875
2876         node = rb_prev(&head->node.rb_node);
2877         if (!node)
2878                 goto out_unlock;
2879
2880         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2881
2882         if (ref->bytenr != bytenr)
2883                 goto out_unlock;
2884
2885         ret = 1;
2886         if (ref->type != BTRFS_EXTENT_DATA_REF_KEY)
2887                 goto out_unlock;
2888
2889         data_ref = btrfs_delayed_node_to_data_ref(ref);
2890
2891         node = rb_prev(node);
2892         if (node) {
2893                 int seq = ref->seq;
2894
2895                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2896                 if (ref->bytenr == bytenr && ref->seq == seq)
2897                         goto out_unlock;
2898         }
2899
2900         if (data_ref->root != root->root_key.objectid ||
2901             data_ref->objectid != objectid || data_ref->offset != offset)
2902                 goto out_unlock;
2903
2904         ret = 0;
2905 out_unlock:
2906         mutex_unlock(&head->mutex);
2907 out:
2908         spin_unlock(&delayed_refs->lock);
2909         return ret;
2910 }
2911
2912 static noinline int check_committed_ref(struct btrfs_trans_handle *trans,
2913                                         struct btrfs_root *root,
2914                                         struct btrfs_path *path,
2915                                         u64 objectid, u64 offset, u64 bytenr)
2916 {
2917         struct btrfs_root *extent_root = root->fs_info->extent_root;
2918         struct extent_buffer *leaf;
2919         struct btrfs_extent_data_ref *ref;
2920         struct btrfs_extent_inline_ref *iref;
2921         struct btrfs_extent_item *ei;
2922         struct btrfs_key key;
2923         u32 item_size;
2924         int ret;
2925
2926         key.objectid = bytenr;
2927         key.offset = (u64)-1;
2928         key.type = BTRFS_EXTENT_ITEM_KEY;
2929
2930         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2931         if (ret < 0)
2932                 goto out;
2933         BUG_ON(ret == 0); /* Corruption */
2934
2935         ret = -ENOENT;
2936         if (path->slots[0] == 0)
2937                 goto out;
2938
2939         path->slots[0]--;
2940         leaf = path->nodes[0];
2941         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2942
2943         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2944                 goto out;
2945
2946         ret = 1;
2947         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2948 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2949         if (item_size < sizeof(*ei)) {
2950                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
2951                 goto out;
2952         }
2953 #endif
2954         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2955
2956         if (item_size != sizeof(*ei) +
2957             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2958                 goto out;
2959
2960         if (btrfs_extent_generation(leaf, ei) <=
2961             btrfs_root_last_snapshot(&root->root_item))
2962                 goto out;
2963
2964         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2965         if (btrfs_extent_inline_ref_type(leaf, iref) !=
2966             BTRFS_EXTENT_DATA_REF_KEY)
2967                 goto out;
2968
2969         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2970         if (btrfs_extent_refs(leaf, ei) !=
2971             btrfs_extent_data_ref_count(leaf, ref) ||
2972             btrfs_extent_data_ref_root(leaf, ref) !=
2973             root->root_key.objectid ||
2974             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2975             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2976                 goto out;
2977
2978         ret = 0;
2979 out:
2980         return ret;
2981 }
2982
2983 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
2984                           struct btrfs_root *root,
2985                           u64 objectid, u64 offset, u64 bytenr)
2986 {
2987         struct btrfs_path *path;
2988         int ret;
2989         int ret2;
2990
2991         path = btrfs_alloc_path();
2992         if (!path)
2993                 return -ENOENT;
2994
2995         do {
2996                 ret = check_committed_ref(trans, root, path, objectid,
2997                                           offset, bytenr);
2998                 if (ret && ret != -ENOENT)
2999                         goto out;
3000
3001                 ret2 = check_delayed_ref(trans, root, path, objectid,
3002                                          offset, bytenr);
3003         } while (ret2 == -EAGAIN);
3004
3005         if (ret2 && ret2 != -ENOENT) {
3006                 ret = ret2;
3007                 goto out;
3008         }
3009
3010         if (ret != -ENOENT || ret2 != -ENOENT)
3011                 ret = 0;
3012 out:
3013         btrfs_free_path(path);
3014         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3015                 WARN_ON(ret > 0);
3016         return ret;
3017 }
3018
3019 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3020                            struct btrfs_root *root,
3021                            struct extent_buffer *buf,
3022                            int full_backref, int inc, int for_cow)
3023 {
3024         u64 bytenr;
3025         u64 num_bytes;
3026         u64 parent;
3027         u64 ref_root;
3028         u32 nritems;
3029         struct btrfs_key key;
3030         struct btrfs_file_extent_item *fi;
3031         int i;
3032         int level;
3033         int ret = 0;
3034         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
3035                             u64, u64, u64, u64, u64, u64, int);
3036
3037         ref_root = btrfs_header_owner(buf);
3038         nritems = btrfs_header_nritems(buf);
3039         level = btrfs_header_level(buf);
3040
3041         if (!root->ref_cows && level == 0)
3042                 return 0;
3043
3044         if (inc)
3045                 process_func = btrfs_inc_extent_ref;
3046         else
3047                 process_func = btrfs_free_extent;
3048
3049         if (full_backref)
3050                 parent = buf->start;
3051         else
3052                 parent = 0;
3053
3054         for (i = 0; i < nritems; i++) {
3055                 if (level == 0) {
3056                         btrfs_item_key_to_cpu(buf, &key, i);
3057                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3058                                 continue;
3059                         fi = btrfs_item_ptr(buf, i,
3060                                             struct btrfs_file_extent_item);
3061                         if (btrfs_file_extent_type(buf, fi) ==
3062                             BTRFS_FILE_EXTENT_INLINE)
3063                                 continue;
3064                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3065                         if (bytenr == 0)
3066                                 continue;
3067
3068                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3069                         key.offset -= btrfs_file_extent_offset(buf, fi);
3070                         ret = process_func(trans, root, bytenr, num_bytes,
3071                                            parent, ref_root, key.objectid,
3072                                            key.offset, for_cow);
3073                         if (ret)
3074                                 goto fail;
3075                 } else {
3076                         bytenr = btrfs_node_blockptr(buf, i);
3077                         num_bytes = btrfs_level_size(root, level - 1);
3078                         ret = process_func(trans, root, bytenr, num_bytes,
3079                                            parent, ref_root, level - 1, 0,
3080                                            for_cow);
3081                         if (ret)
3082                                 goto fail;
3083                 }
3084         }
3085         return 0;
3086 fail:
3087         return ret;
3088 }
3089
3090 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3091                   struct extent_buffer *buf, int full_backref, int for_cow)
3092 {
3093         return __btrfs_mod_ref(trans, root, buf, full_backref, 1, for_cow);
3094 }
3095
3096 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3097                   struct extent_buffer *buf, int full_backref, int for_cow)
3098 {
3099         return __btrfs_mod_ref(trans, root, buf, full_backref, 0, for_cow);
3100 }
3101
3102 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3103                                  struct btrfs_root *root,
3104                                  struct btrfs_path *path,
3105                                  struct btrfs_block_group_cache *cache)
3106 {
3107         int ret;
3108         struct btrfs_root *extent_root = root->fs_info->extent_root;
3109         unsigned long bi;
3110         struct extent_buffer *leaf;
3111
3112         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3113         if (ret < 0)
3114                 goto fail;
3115         BUG_ON(ret); /* Corruption */
3116
3117         leaf = path->nodes[0];
3118         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3119         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3120         btrfs_mark_buffer_dirty(leaf);
3121         btrfs_release_path(path);
3122 fail:
3123         if (ret) {
3124                 btrfs_abort_transaction(trans, root, ret);
3125                 return ret;
3126         }
3127         return 0;
3128
3129 }
3130
3131 static struct btrfs_block_group_cache *
3132 next_block_group(struct btrfs_root *root,
3133                  struct btrfs_block_group_cache *cache)
3134 {
3135         struct rb_node *node;
3136         spin_lock(&root->fs_info->block_group_cache_lock);
3137         node = rb_next(&cache->cache_node);
3138         btrfs_put_block_group(cache);
3139         if (node) {
3140                 cache = rb_entry(node, struct btrfs_block_group_cache,
3141                                  cache_node);
3142                 btrfs_get_block_group(cache);
3143         } else
3144                 cache = NULL;
3145         spin_unlock(&root->fs_info->block_group_cache_lock);
3146         return cache;
3147 }
3148
3149 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3150                             struct btrfs_trans_handle *trans,
3151                             struct btrfs_path *path)
3152 {
3153         struct btrfs_root *root = block_group->fs_info->tree_root;
3154         struct inode *inode = NULL;
3155         u64 alloc_hint = 0;
3156         int dcs = BTRFS_DC_ERROR;
3157         int num_pages = 0;
3158         int retries = 0;
3159         int ret = 0;
3160
3161         /*
3162          * If this block group is smaller than 100 megs don't bother caching the
3163          * block group.
3164          */
3165         if (block_group->key.offset < (100 * 1024 * 1024)) {
3166                 spin_lock(&block_group->lock);
3167                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3168                 spin_unlock(&block_group->lock);
3169                 return 0;
3170         }
3171
3172 again:
3173         inode = lookup_free_space_inode(root, block_group, path);
3174         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3175                 ret = PTR_ERR(inode);
3176                 btrfs_release_path(path);
3177                 goto out;
3178         }
3179
3180         if (IS_ERR(inode)) {
3181                 BUG_ON(retries);
3182                 retries++;
3183
3184                 if (block_group->ro)
3185                         goto out_free;
3186
3187                 ret = create_free_space_inode(root, trans, block_group, path);
3188                 if (ret)
3189                         goto out_free;
3190                 goto again;
3191         }
3192
3193         /* We've already setup this transaction, go ahead and exit */
3194         if (block_group->cache_generation == trans->transid &&
3195             i_size_read(inode)) {
3196                 dcs = BTRFS_DC_SETUP;
3197                 goto out_put;
3198         }
3199
3200         /*
3201          * We want to set the generation to 0, that way if anything goes wrong
3202          * from here on out we know not to trust this cache when we load up next
3203          * time.
3204          */
3205         BTRFS_I(inode)->generation = 0;
3206         ret = btrfs_update_inode(trans, root, inode);
3207         WARN_ON(ret);
3208
3209         if (i_size_read(inode) > 0) {
3210                 ret = btrfs_check_trunc_cache_free_space(root,
3211                                         &root->fs_info->global_block_rsv);
3212                 if (ret)
3213                         goto out_put;
3214
3215                 ret = btrfs_truncate_free_space_cache(root, trans, inode);
3216                 if (ret)
3217                         goto out_put;
3218         }
3219
3220         spin_lock(&block_group->lock);
3221         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3222             !btrfs_test_opt(root, SPACE_CACHE)) {
3223                 /*
3224                  * don't bother trying to write stuff out _if_
3225                  * a) we're not cached,
3226                  * b) we're with nospace_cache mount option.
3227                  */
3228                 dcs = BTRFS_DC_WRITTEN;
3229                 spin_unlock(&block_group->lock);
3230                 goto out_put;
3231         }
3232         spin_unlock(&block_group->lock);
3233
3234         /*
3235          * Try to preallocate enough space based on how big the block group is.
3236          * Keep in mind this has to include any pinned space which could end up
3237          * taking up quite a bit since it's not folded into the other space
3238          * cache.
3239          */
3240         num_pages = (int)div64_u64(block_group->key.offset, 256 * 1024 * 1024);
3241         if (!num_pages)
3242                 num_pages = 1;
3243
3244         num_pages *= 16;
3245         num_pages *= PAGE_CACHE_SIZE;
3246
3247         ret = btrfs_check_data_free_space(inode, num_pages);
3248         if (ret)
3249                 goto out_put;
3250
3251         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3252                                               num_pages, num_pages,
3253                                               &alloc_hint);
3254         if (!ret)
3255                 dcs = BTRFS_DC_SETUP;
3256         btrfs_free_reserved_data_space(inode, num_pages);
3257
3258 out_put:
3259         iput(inode);
3260 out_free:
3261         btrfs_release_path(path);
3262 out:
3263         spin_lock(&block_group->lock);
3264         if (!ret && dcs == BTRFS_DC_SETUP)
3265                 block_group->cache_generation = trans->transid;
3266         block_group->disk_cache_state = dcs;
3267         spin_unlock(&block_group->lock);
3268
3269         return ret;
3270 }
3271
3272 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3273                                    struct btrfs_root *root)
3274 {
3275         struct btrfs_block_group_cache *cache;
3276         int err = 0;
3277         struct btrfs_path *path;
3278         u64 last = 0;
3279
3280         path = btrfs_alloc_path();
3281         if (!path)
3282                 return -ENOMEM;
3283
3284 again:
3285         while (1) {
3286                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3287                 while (cache) {
3288                         if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3289                                 break;
3290                         cache = next_block_group(root, cache);
3291                 }
3292                 if (!cache) {
3293                         if (last == 0)
3294                                 break;
3295                         last = 0;
3296                         continue;
3297                 }
3298                 err = cache_save_setup(cache, trans, path);
3299                 last = cache->key.objectid + cache->key.offset;
3300                 btrfs_put_block_group(cache);
3301         }
3302
3303         while (1) {
3304                 if (last == 0) {
3305                         err = btrfs_run_delayed_refs(trans, root,
3306                                                      (unsigned long)-1);
3307                         if (err) /* File system offline */
3308                                 goto out;
3309                 }
3310
3311                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3312                 while (cache) {
3313                         if (cache->disk_cache_state == BTRFS_DC_CLEAR) {
3314                                 btrfs_put_block_group(cache);
3315                                 goto again;
3316                         }
3317
3318                         if (cache->dirty)
3319                                 break;
3320                         cache = next_block_group(root, cache);
3321                 }
3322                 if (!cache) {
3323                         if (last == 0)
3324                                 break;
3325                         last = 0;
3326                         continue;
3327                 }
3328
3329                 if (cache->disk_cache_state == BTRFS_DC_SETUP)
3330                         cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
3331                 cache->dirty = 0;
3332                 last = cache->key.objectid + cache->key.offset;
3333
3334                 err = write_one_cache_group(trans, root, path, cache);
3335                 btrfs_put_block_group(cache);
3336                 if (err) /* File system offline */
3337                         goto out;
3338         }
3339
3340         while (1) {
3341                 /*
3342                  * I don't think this is needed since we're just marking our
3343                  * preallocated extent as written, but just in case it can't
3344                  * hurt.
3345                  */
3346                 if (last == 0) {
3347                         err = btrfs_run_delayed_refs(trans, root,
3348                                                      (unsigned long)-1);
3349                         if (err) /* File system offline */
3350                                 goto out;
3351                 }
3352
3353                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
3354                 while (cache) {
3355                         /*
3356                          * Really this shouldn't happen, but it could if we
3357                          * couldn't write the entire preallocated extent and
3358                          * splitting the extent resulted in a new block.
3359                          */
3360                         if (cache->dirty) {
3361                                 btrfs_put_block_group(cache);
3362                                 goto again;
3363                         }
3364                         if (cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3365                                 break;
3366                         cache = next_block_group(root, cache);
3367                 }
3368                 if (!cache) {
3369                         if (last == 0)
3370                                 break;
3371                         last = 0;
3372                         continue;
3373                 }
3374
3375                 err = btrfs_write_out_cache(root, trans, cache, path);
3376
3377                 /*
3378                  * If we didn't have an error then the cache state is still
3379                  * NEED_WRITE, so we can set it to WRITTEN.
3380                  */
3381                 if (!err && cache->disk_cache_state == BTRFS_DC_NEED_WRITE)
3382                         cache->disk_cache_state = BTRFS_DC_WRITTEN;
3383                 last = cache->key.objectid + cache->key.offset;
3384                 btrfs_put_block_group(cache);
3385         }
3386 out:
3387
3388         btrfs_free_path(path);
3389         return err;
3390 }
3391
3392 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
3393 {
3394         struct btrfs_block_group_cache *block_group;
3395         int readonly = 0;
3396
3397         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
3398         if (!block_group || block_group->ro)
3399                 readonly = 1;
3400         if (block_group)
3401                 btrfs_put_block_group(block_group);
3402         return readonly;
3403 }
3404
3405 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
3406                              u64 total_bytes, u64 bytes_used,
3407                              struct btrfs_space_info **space_info)
3408 {
3409         struct btrfs_space_info *found;
3410         int i;
3411         int factor;
3412         int ret;
3413
3414         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3415                      BTRFS_BLOCK_GROUP_RAID10))
3416                 factor = 2;
3417         else
3418                 factor = 1;
3419
3420         found = __find_space_info(info, flags);
3421         if (found) {
3422                 spin_lock(&found->lock);
3423                 found->total_bytes += total_bytes;
3424                 found->disk_total += total_bytes * factor;
3425                 found->bytes_used += bytes_used;
3426                 found->disk_used += bytes_used * factor;
3427                 found->full = 0;
3428                 spin_unlock(&found->lock);
3429                 *space_info = found;
3430                 return 0;
3431         }
3432         found = kzalloc(sizeof(*found), GFP_NOFS);
3433         if (!found)
3434                 return -ENOMEM;
3435
3436         ret = percpu_counter_init(&found->total_bytes_pinned, 0);
3437         if (ret) {
3438                 kfree(found);
3439                 return ret;
3440         }
3441
3442         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
3443                 INIT_LIST_HEAD(&found->block_groups[i]);
3444         init_rwsem(&found->groups_sem);
3445         spin_lock_init(&found->lock);
3446         found->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
3447         found->total_bytes = total_bytes;
3448         found->disk_total = total_bytes * factor;
3449         found->bytes_used = bytes_used;
3450         found->disk_used = bytes_used * factor;
3451         found->bytes_pinned = 0;
3452         found->bytes_reserved = 0;
3453         found->bytes_readonly = 0;
3454         found->bytes_may_use = 0;
3455         found->full = 0;
3456         found->force_alloc = CHUNK_ALLOC_NO_FORCE;
3457         found->chunk_alloc = 0;
3458         found->flush = 0;
3459         init_waitqueue_head(&found->wait);
3460         *space_info = found;
3461         list_add_rcu(&found->list, &info->space_info);
3462         if (flags & BTRFS_BLOCK_GROUP_DATA)
3463                 info->data_sinfo = found;
3464         return 0;
3465 }
3466
3467 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
3468 {
3469         u64 extra_flags = chunk_to_extended(flags) &
3470                                 BTRFS_EXTENDED_PROFILE_MASK;
3471
3472         write_seqlock(&fs_info->profiles_lock);
3473         if (flags & BTRFS_BLOCK_GROUP_DATA)
3474                 fs_info->avail_data_alloc_bits |= extra_flags;
3475         if (flags & BTRFS_BLOCK_GROUP_METADATA)
3476                 fs_info->avail_metadata_alloc_bits |= extra_flags;
3477         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3478                 fs_info->avail_system_alloc_bits |= extra_flags;
3479         write_sequnlock(&fs_info->profiles_lock);
3480 }
3481
3482 /*
3483  * returns target flags in extended format or 0 if restripe for this
3484  * chunk_type is not in progress
3485  *
3486  * should be called with either volume_mutex or balance_lock held
3487  */
3488 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
3489 {
3490         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3491         u64 target = 0;
3492
3493         if (!bctl)
3494                 return 0;
3495
3496         if (flags & BTRFS_BLOCK_GROUP_DATA &&
3497             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3498                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
3499         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
3500                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3501                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
3502         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
3503                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3504                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
3505         }
3506
3507         return target;
3508 }
3509
3510 /*
3511  * @flags: available profiles in extended format (see ctree.h)
3512  *
3513  * Returns reduced profile in chunk format.  If profile changing is in
3514  * progress (either running or paused) picks the target profile (if it's
3515  * already available), otherwise falls back to plain reducing.
3516  */
3517 static u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
3518 {
3519         /*
3520          * we add in the count of missing devices because we want
3521          * to make sure that any RAID levels on a degraded FS
3522          * continue to be honored.
3523          */
3524         u64 num_devices = root->fs_info->fs_devices->rw_devices +
3525                 root->fs_info->fs_devices->missing_devices;
3526         u64 target;
3527         u64 tmp;
3528
3529         /*
3530          * see if restripe for this chunk_type is in progress, if so
3531          * try to reduce to the target profile
3532          */
3533         spin_lock(&root->fs_info->balance_lock);
3534         target = get_restripe_target(root->fs_info, flags);
3535         if (target) {
3536                 /* pick target profile only if it's already available */
3537                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
3538                         spin_unlock(&root->fs_info->balance_lock);
3539                         return extended_to_chunk(target);
3540                 }
3541         }
3542         spin_unlock(&root->fs_info->balance_lock);
3543
3544         /* First, mask out the RAID levels which aren't possible */
3545         if (num_devices == 1)
3546                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0 |
3547                            BTRFS_BLOCK_GROUP_RAID5);
3548         if (num_devices < 3)
3549                 flags &= ~BTRFS_BLOCK_GROUP_RAID6;
3550         if (num_devices < 4)
3551                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
3552
3553         tmp = flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
3554                        BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID5 |
3555                        BTRFS_BLOCK_GROUP_RAID6 | BTRFS_BLOCK_GROUP_RAID10);
3556         flags &= ~tmp;
3557
3558         if (tmp & BTRFS_BLOCK_GROUP_RAID6)
3559                 tmp = BTRFS_BLOCK_GROUP_RAID6;
3560         else if (tmp & BTRFS_BLOCK_GROUP_RAID5)
3561                 tmp = BTRFS_BLOCK_GROUP_RAID5;
3562         else if (tmp & BTRFS_BLOCK_GROUP_RAID10)
3563                 tmp = BTRFS_BLOCK_GROUP_RAID10;
3564         else if (tmp & BTRFS_BLOCK_GROUP_RAID1)
3565                 tmp = BTRFS_BLOCK_GROUP_RAID1;
3566         else if (tmp & BTRFS_BLOCK_GROUP_RAID0)
3567                 tmp = BTRFS_BLOCK_GROUP_RAID0;
3568
3569         return extended_to_chunk(flags | tmp);
3570 }
3571
3572 static u64 get_alloc_profile(struct btrfs_root *root, u64 flags)
3573 {
3574         unsigned seq;
3575
3576         do {
3577                 seq = read_seqbegin(&root->fs_info->profiles_lock);
3578
3579                 if (flags & BTRFS_BLOCK_GROUP_DATA)
3580                         flags |= root->fs_info->avail_data_alloc_bits;
3581                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
3582                         flags |= root->fs_info->avail_system_alloc_bits;
3583                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
3584                         flags |= root->fs_info->avail_metadata_alloc_bits;
3585         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
3586
3587         return btrfs_reduce_alloc_profile(root, flags);
3588 }
3589
3590 u64 btrfs_get_alloc_profile(struct btrfs_root *root, int data)
3591 {
3592         u64 flags;
3593         u64 ret;
3594
3595         if (data)
3596                 flags = BTRFS_BLOCK_GROUP_DATA;
3597         else if (root == root->fs_info->chunk_root)
3598                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
3599         else
3600                 flags = BTRFS_BLOCK_GROUP_METADATA;
3601
3602         ret = get_alloc_profile(root, flags);
3603         return ret;
3604 }
3605
3606 /*
3607  * This will check the space that the inode allocates from to make sure we have
3608  * enough space for bytes.
3609  */
3610 int btrfs_check_data_free_space(struct inode *inode, u64 bytes)
3611 {
3612         struct btrfs_space_info *data_sinfo;
3613         struct btrfs_root *root = BTRFS_I(inode)->root;
3614         struct btrfs_fs_info *fs_info = root->fs_info;
3615         u64 used;
3616         int ret = 0, committed = 0, alloc_chunk = 1;
3617
3618         /* make sure bytes are sectorsize aligned */
3619         bytes = ALIGN(bytes, root->sectorsize);
3620
3621         if (btrfs_is_free_space_inode(inode)) {
3622                 committed = 1;
3623                 ASSERT(current->journal_info);
3624         }
3625
3626         data_sinfo = fs_info->data_sinfo;
3627         if (!data_sinfo)
3628                 goto alloc;
3629
3630 again:
3631         /* make sure we have enough space to handle the data first */
3632         spin_lock(&data_sinfo->lock);
3633         used = data_sinfo->bytes_used + data_sinfo->bytes_reserved +
3634                 data_sinfo->bytes_pinned + data_sinfo->bytes_readonly +
3635                 data_sinfo->bytes_may_use;
3636
3637         if (used + bytes > data_sinfo->total_bytes) {
3638                 struct btrfs_trans_handle *trans;
3639
3640                 /*
3641                  * if we don't have enough free bytes in this space then we need
3642                  * to alloc a new chunk.
3643                  */
3644                 if (!data_sinfo->full && alloc_chunk) {
3645                         u64 alloc_target;
3646
3647                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
3648                         spin_unlock(&data_sinfo->lock);
3649 alloc:
3650                         alloc_target = btrfs_get_alloc_profile(root, 1);
3651                         /*
3652                          * It is ugly that we don't call nolock join
3653                          * transaction for the free space inode case here.
3654                          * But it is safe because we only do the data space
3655                          * reservation for the free space cache in the
3656                          * transaction context, the common join transaction
3657                          * just increase the counter of the current transaction
3658                          * handler, doesn't try to acquire the trans_lock of
3659                          * the fs.
3660                          */
3661                         trans = btrfs_join_transaction(root);
3662                         if (IS_ERR(trans))
3663                                 return PTR_ERR(trans);
3664
3665                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3666                                              alloc_target,
3667                                              CHUNK_ALLOC_NO_FORCE);
3668                         btrfs_end_transaction(trans, root);
3669                         if (ret < 0) {
3670                                 if (ret != -ENOSPC)
3671                                         return ret;
3672                                 else
3673                                         goto commit_trans;
3674                         }
3675
3676                         if (!data_sinfo)
3677                                 data_sinfo = fs_info->data_sinfo;
3678
3679                         goto again;
3680                 }
3681
3682                 /*
3683                  * If we don't have enough pinned space to deal with this
3684                  * allocation don't bother committing the transaction.
3685                  */
3686                 if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
3687                                            bytes) < 0)
3688                         committed = 1;
3689                 spin_unlock(&data_sinfo->lock);
3690
3691                 /* commit the current transaction and try again */
3692 commit_trans:
3693                 if (!committed &&
3694                     !atomic_read(&root->fs_info->open_ioctl_trans)) {
3695                         committed = 1;
3696
3697                         trans = btrfs_join_transaction(root);
3698                         if (IS_ERR(trans))
3699                                 return PTR_ERR(trans);
3700                         ret = btrfs_commit_transaction(trans, root);
3701                         if (ret)
3702                                 return ret;
3703                         goto again;
3704                 }
3705
3706                 trace_btrfs_space_reservation(root->fs_info,
3707                                               "space_info:enospc",
3708                                               data_sinfo->flags, bytes, 1);
3709                 return -ENOSPC;
3710         }
3711         data_sinfo->bytes_may_use += bytes;
3712         trace_btrfs_space_reservation(root->fs_info, "space_info",
3713                                       data_sinfo->flags, bytes, 1);
3714         spin_unlock(&data_sinfo->lock);
3715
3716         return 0;
3717 }
3718
3719 /*
3720  * Called if we need to clear a data reservation for this inode.
3721  */
3722 void btrfs_free_reserved_data_space(struct inode *inode, u64 bytes)
3723 {
3724         struct btrfs_root *root = BTRFS_I(inode)->root;
3725         struct btrfs_space_info *data_sinfo;
3726
3727         /* make sure bytes are sectorsize aligned */
3728         bytes = ALIGN(bytes, root->sectorsize);
3729
3730         data_sinfo = root->fs_info->data_sinfo;
3731         spin_lock(&data_sinfo->lock);
3732         WARN_ON(data_sinfo->bytes_may_use < bytes);
3733         data_sinfo->bytes_may_use -= bytes;
3734         trace_btrfs_space_reservation(root->fs_info, "space_info",
3735                                       data_sinfo->flags, bytes, 0);
3736         spin_unlock(&data_sinfo->lock);
3737 }
3738
3739 static void force_metadata_allocation(struct btrfs_fs_info *info)
3740 {
3741         struct list_head *head = &info->space_info;
3742         struct btrfs_space_info *found;
3743
3744         rcu_read_lock();
3745         list_for_each_entry_rcu(found, head, list) {
3746                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
3747                         found->force_alloc = CHUNK_ALLOC_FORCE;
3748         }
3749         rcu_read_unlock();
3750 }
3751
3752 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
3753 {
3754         return (global->size << 1);
3755 }
3756
3757 static int should_alloc_chunk(struct btrfs_root *root,
3758                               struct btrfs_space_info *sinfo, int force)
3759 {
3760         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3761         u64 num_bytes = sinfo->total_bytes - sinfo->bytes_readonly;
3762         u64 num_allocated = sinfo->bytes_used + sinfo->bytes_reserved;
3763         u64 thresh;
3764
3765         if (force == CHUNK_ALLOC_FORCE)
3766                 return 1;
3767
3768         /*
3769          * We need to take into account the global rsv because for all intents
3770          * and purposes it's used space.  Don't worry about locking the
3771          * global_rsv, it doesn't change except when the transaction commits.
3772          */
3773         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
3774                 num_allocated += calc_global_rsv_need_space(global_rsv);
3775
3776         /*
3777          * in limited mode, we want to have some free space up to
3778          * about 1% of the FS size.
3779          */
3780         if (force == CHUNK_ALLOC_LIMITED) {
3781                 thresh = btrfs_super_total_bytes(root->fs_info->super_copy);
3782                 thresh = max_t(u64, 64 * 1024 * 1024,
3783                                div_factor_fine(thresh, 1));
3784
3785                 if (num_bytes - num_allocated < thresh)
3786                         return 1;
3787         }
3788
3789         if (num_allocated + 2 * 1024 * 1024 < div_factor(num_bytes, 8))
3790                 return 0;
3791         return 1;
3792 }
3793
3794 static u64 get_system_chunk_thresh(struct btrfs_root *root, u64 type)
3795 {
3796         u64 num_dev;
3797
3798         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
3799                     BTRFS_BLOCK_GROUP_RAID0 |
3800                     BTRFS_BLOCK_GROUP_RAID5 |
3801                     BTRFS_BLOCK_GROUP_RAID6))
3802                 num_dev = root->fs_info->fs_devices->rw_devices;
3803         else if (type & BTRFS_BLOCK_GROUP_RAID1)
3804                 num_dev = 2;
3805         else
3806                 num_dev = 1;    /* DUP or single */
3807
3808         /* metadata for updaing devices and chunk tree */
3809         return btrfs_calc_trans_metadata_size(root, num_dev + 1);
3810 }
3811
3812 static void check_system_chunk(struct btrfs_trans_handle *trans,
3813                                struct btrfs_root *root, u64 type)
3814 {
3815         struct btrfs_space_info *info;
3816         u64 left;
3817         u64 thresh;
3818
3819         info = __find_space_info(root->fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
3820         spin_lock(&info->lock);
3821         left = info->total_bytes - info->bytes_used - info->bytes_pinned -
3822                 info->bytes_reserved - info->bytes_readonly;
3823         spin_unlock(&info->lock);
3824
3825         thresh = get_system_chunk_thresh(root, type);
3826         if (left < thresh && btrfs_test_opt(root, ENOSPC_DEBUG)) {
3827                 btrfs_info(root->fs_info, "left=%llu, need=%llu, flags=%llu",
3828                         left, thresh, type);
3829                 dump_space_info(info, 0, 0);
3830         }
3831
3832         if (left < thresh) {
3833                 u64 flags;
3834
3835                 flags = btrfs_get_alloc_profile(root->fs_info->chunk_root, 0);
3836                 btrfs_alloc_chunk(trans, root, flags);
3837         }
3838 }
3839
3840 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
3841                           struct btrfs_root *extent_root, u64 flags, int force)
3842 {
3843         struct btrfs_space_info *space_info;
3844         struct btrfs_fs_info *fs_info = extent_root->fs_info;
3845         int wait_for_alloc = 0;
3846         int ret = 0;
3847
3848         /* Don't re-enter if we're already allocating a chunk */
3849         if (trans->allocating_chunk)
3850                 return -ENOSPC;
3851
3852         space_info = __find_space_info(extent_root->fs_info, flags);
3853         if (!space_info) {
3854                 ret = update_space_info(extent_root->fs_info, flags,
3855                                         0, 0, &space_info);
3856                 BUG_ON(ret); /* -ENOMEM */
3857         }
3858         BUG_ON(!space_info); /* Logic error */
3859
3860 again:
3861         spin_lock(&space_info->lock);
3862         if (force < space_info->force_alloc)
3863                 force = space_info->force_alloc;
3864         if (space_info->full) {
3865                 if (should_alloc_chunk(extent_root, space_info, force))
3866                         ret = -ENOSPC;
3867                 else
3868                         ret = 0;
3869                 spin_unlock(&space_info->lock);
3870                 return ret;
3871         }
3872
3873         if (!should_alloc_chunk(extent_root, space_info, force)) {
3874                 spin_unlock(&space_info->lock);
3875                 return 0;
3876         } else if (space_info->chunk_alloc) {
3877                 wait_for_alloc = 1;
3878         } else {
3879                 space_info->chunk_alloc = 1;
3880         }
3881
3882         spin_unlock(&space_info->lock);
3883
3884         mutex_lock(&fs_info->chunk_mutex);
3885
3886         /*
3887          * The chunk_mutex is held throughout the entirety of a chunk
3888          * allocation, so once we've acquired the chunk_mutex we know that the
3889          * other guy is done and we need to recheck and see if we should
3890          * allocate.
3891          */
3892         if (wait_for_alloc) {
3893                 mutex_unlock(&fs_info->chunk_mutex);
3894                 wait_for_alloc = 0;
3895                 goto again;
3896         }
3897
3898         trans->allocating_chunk = true;
3899
3900         /*
3901          * If we have mixed data/metadata chunks we want to make sure we keep
3902          * allocating mixed chunks instead of individual chunks.
3903          */
3904         if (btrfs_mixed_space_info(space_info))
3905                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
3906
3907         /*
3908          * if we're doing a data chunk, go ahead and make sure that
3909          * we keep a reasonable number of metadata chunks allocated in the
3910          * FS as well.
3911          */
3912         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
3913                 fs_info->data_chunk_allocations++;
3914                 if (!(fs_info->data_chunk_allocations %
3915                       fs_info->metadata_ratio))
3916                         force_metadata_allocation(fs_info);
3917         }
3918
3919         /*
3920          * Check if we have enough space in SYSTEM chunk because we may need
3921          * to update devices.
3922          */
3923         check_system_chunk(trans, extent_root, flags);
3924
3925         ret = btrfs_alloc_chunk(trans, extent_root, flags);
3926         trans->allocating_chunk = false;
3927
3928         spin_lock(&space_info->lock);
3929         if (ret < 0 && ret != -ENOSPC)
3930                 goto out;
3931         if (ret)
3932                 space_info->full = 1;
3933         else
3934                 ret = 1;
3935
3936         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
3937 out:
3938         space_info->chunk_alloc = 0;
3939         spin_unlock(&space_info->lock);
3940         mutex_unlock(&fs_info->chunk_mutex);
3941         return ret;
3942 }
3943
3944 static int can_overcommit(struct btrfs_root *root,
3945                           struct btrfs_space_info *space_info, u64 bytes,
3946                           enum btrfs_reserve_flush_enum flush)
3947 {
3948         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
3949         u64 profile = btrfs_get_alloc_profile(root, 0);
3950         u64 space_size;
3951         u64 avail;
3952         u64 used;
3953
3954         used = space_info->bytes_used + space_info->bytes_reserved +
3955                 space_info->bytes_pinned + space_info->bytes_readonly;
3956
3957         /*
3958          * We only want to allow over committing if we have lots of actual space
3959          * free, but if we don't have enough space to handle the global reserve
3960          * space then we could end up having a real enospc problem when trying
3961          * to allocate a chunk or some other such important allocation.
3962          */
3963         spin_lock(&global_rsv->lock);
3964         space_size = calc_global_rsv_need_space(global_rsv);
3965         spin_unlock(&global_rsv->lock);
3966         if (used + space_size >= space_info->total_bytes)
3967                 return 0;
3968
3969         used += space_info->bytes_may_use;
3970
3971         spin_lock(&root->fs_info->free_chunk_lock);
3972         avail = root->fs_info->free_chunk_space;
3973         spin_unlock(&root->fs_info->free_chunk_lock);
3974
3975         /*
3976          * If we have dup, raid1 or raid10 then only half of the free
3977          * space is actually useable.  For raid56, the space info used
3978          * doesn't include the parity drive, so we don't have to
3979          * change the math
3980          */
3981         if (profile & (BTRFS_BLOCK_GROUP_DUP |
3982                        BTRFS_BLOCK_GROUP_RAID1 |
3983                        BTRFS_BLOCK_GROUP_RAID10))
3984                 avail >>= 1;
3985
3986         /*
3987          * If we aren't flushing all things, let us overcommit up to
3988          * 1/2th of the space. If we can flush, don't let us overcommit
3989          * too much, let it overcommit up to 1/8 of the space.
3990          */
3991         if (flush == BTRFS_RESERVE_FLUSH_ALL)
3992                 avail >>= 3;
3993         else
3994                 avail >>= 1;
3995
3996         if (used + bytes < space_info->total_bytes + avail)
3997                 return 1;
3998         return 0;
3999 }
4000
4001 static void btrfs_writeback_inodes_sb_nr(struct btrfs_root *root,
4002                                          unsigned long nr_pages)
4003 {
4004         struct super_block *sb = root->fs_info->sb;
4005
4006         if (down_read_trylock(&sb->s_umount)) {
4007                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4008                 up_read(&sb->s_umount);
4009         } else {
4010                 /*
4011                  * We needn't worry the filesystem going from r/w to r/o though
4012                  * we don't acquire ->s_umount mutex, because the filesystem
4013                  * should guarantee the delalloc inodes list be empty after
4014                  * the filesystem is readonly(all dirty pages are written to
4015                  * the disk).
4016                  */
4017                 btrfs_start_delalloc_roots(root->fs_info, 0);
4018                 if (!current->journal_info)
4019                         btrfs_wait_ordered_roots(root->fs_info, -1);
4020         }
4021 }
4022
4023 static inline int calc_reclaim_items_nr(struct btrfs_root *root, u64 to_reclaim)
4024 {
4025         u64 bytes;
4026         int nr;
4027
4028         bytes = btrfs_calc_trans_metadata_size(root, 1);
4029         nr = (int)div64_u64(to_reclaim, bytes);
4030         if (!nr)
4031                 nr = 1;
4032         return nr;
4033 }
4034
4035 #define EXTENT_SIZE_PER_ITEM    (256 * 1024)
4036
4037 /*
4038  * shrink metadata reservation for delalloc
4039  */
4040 static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
4041                             bool wait_ordered)
4042 {
4043         struct btrfs_block_rsv *block_rsv;
4044         struct btrfs_space_info *space_info;
4045         struct btrfs_trans_handle *trans;
4046         u64 delalloc_bytes;
4047         u64 max_reclaim;
4048         long time_left;
4049         unsigned long nr_pages;
4050         int loops;
4051         int items;
4052         enum btrfs_reserve_flush_enum flush;
4053
4054         /* Calc the number of the pages we need flush for space reservation */
4055         items = calc_reclaim_items_nr(root, to_reclaim);
4056         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4057
4058         trans = (struct btrfs_trans_handle *)current->journal_info;
4059         block_rsv = &root->fs_info->delalloc_block_rsv;
4060         space_info = block_rsv->space_info;
4061
4062         delalloc_bytes = percpu_counter_sum_positive(
4063                                                 &root->fs_info->delalloc_bytes);
4064         if (delalloc_bytes == 0) {
4065                 if (trans)
4066                         return;
4067                 if (wait_ordered)
4068                         btrfs_wait_ordered_roots(root->fs_info, items);
4069                 return;
4070         }
4071
4072         loops = 0;
4073         while (delalloc_bytes && loops < 3) {
4074                 max_reclaim = min(delalloc_bytes, to_reclaim);
4075                 nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
4076                 btrfs_writeback_inodes_sb_nr(root, nr_pages);
4077                 /*
4078                  * We need to wait for the async pages to actually start before
4079                  * we do anything.
4080                  */
4081                 max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages);
4082                 if (!max_reclaim)
4083                         goto skip_async;
4084
4085                 if (max_reclaim <= nr_pages)
4086                         max_reclaim = 0;
4087                 else
4088                         max_reclaim -= nr_pages;
4089
4090                 wait_event(root->fs_info->async_submit_wait,
4091                            atomic_read(&root->fs_info->async_delalloc_pages) <=
4092                            (int)max_reclaim);
4093 skip_async:
4094                 if (!trans)
4095                         flush = BTRFS_RESERVE_FLUSH_ALL;
4096                 else
4097                         flush = BTRFS_RESERVE_NO_FLUSH;
4098                 spin_lock(&space_info->lock);
4099                 if (can_overcommit(root, space_info, orig, flush)) {
4100                         spin_unlock(&space_info->lock);
4101                         break;
4102                 }
4103                 spin_unlock(&space_info->lock);
4104
4105                 loops++;
4106                 if (wait_ordered && !trans) {
4107                         btrfs_wait_ordered_roots(root->fs_info, items);
4108                 } else {
4109                         time_left = schedule_timeout_killable(1);
4110                         if (time_left)
4111                                 break;
4112                 }
4113                 delalloc_bytes = percpu_counter_sum_positive(
4114                                                 &root->fs_info->delalloc_bytes);
4115         }
4116 }
4117
4118 /**
4119  * maybe_commit_transaction - possibly commit the transaction if its ok to
4120  * @root - the root we're allocating for
4121  * @bytes - the number of bytes we want to reserve
4122  * @force - force the commit
4123  *
4124  * This will check to make sure that committing the transaction will actually
4125  * get us somewhere and then commit the transaction if it does.  Otherwise it
4126  * will return -ENOSPC.
4127  */
4128 static int may_commit_transaction(struct btrfs_root *root,
4129                                   struct btrfs_space_info *space_info,
4130                                   u64 bytes, int force)
4131 {
4132         struct btrfs_block_rsv *delayed_rsv = &root->fs_info->delayed_block_rsv;
4133         struct btrfs_trans_handle *trans;
4134
4135         trans = (struct btrfs_trans_handle *)current->journal_info;
4136         if (trans)
4137                 return -EAGAIN;
4138
4139         if (force)
4140                 goto commit;
4141
4142         /* See if there is enough pinned space to make this reservation */
4143         spin_lock(&space_info->lock);
4144         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4145                                    bytes) >= 0) {
4146                 spin_unlock(&space_info->lock);
4147                 goto commit;
4148         }
4149         spin_unlock(&space_info->lock);
4150
4151         /*
4152          * See if there is some space in the delayed insertion reservation for
4153          * this reservation.
4154          */
4155         if (space_info != delayed_rsv->space_info)
4156                 return -ENOSPC;
4157
4158         spin_lock(&space_info->lock);
4159         spin_lock(&delayed_rsv->lock);
4160         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4161                                    bytes - delayed_rsv->size) >= 0) {
4162                 spin_unlock(&delayed_rsv->lock);
4163                 spin_unlock(&space_info->lock);
4164                 return -ENOSPC;
4165         }
4166         spin_unlock(&delayed_rsv->lock);
4167         spin_unlock(&space_info->lock);
4168
4169 commit:
4170         trans = btrfs_join_transaction(root);
4171         if (IS_ERR(trans))
4172                 return -ENOSPC;
4173
4174         return btrfs_commit_transaction(trans, root);
4175 }
4176
4177 enum flush_state {
4178         FLUSH_DELAYED_ITEMS_NR  =       1,
4179         FLUSH_DELAYED_ITEMS     =       2,
4180         FLUSH_DELALLOC          =       3,
4181         FLUSH_DELALLOC_WAIT     =       4,
4182         ALLOC_CHUNK             =       5,
4183         COMMIT_TRANS            =       6,
4184 };
4185
4186 static int flush_space(struct btrfs_root *root,
4187                        struct btrfs_space_info *space_info, u64 num_bytes,
4188                        u64 orig_bytes, int state)
4189 {
4190         struct btrfs_trans_handle *trans;
4191         int nr;
4192         int ret = 0;
4193
4194         switch (state) {
4195         case FLUSH_DELAYED_ITEMS_NR:
4196         case FLUSH_DELAYED_ITEMS:
4197                 if (state == FLUSH_DELAYED_ITEMS_NR)
4198                         nr = calc_reclaim_items_nr(root, num_bytes) * 2;
4199                 else
4200                         nr = -1;
4201
4202                 trans = btrfs_join_transaction(root);
4203                 if (IS_ERR(trans)) {
4204                         ret = PTR_ERR(trans);
4205                         break;
4206                 }
4207                 ret = btrfs_run_delayed_items_nr(trans, root, nr);
4208                 btrfs_end_transaction(trans, root);
4209                 break;
4210         case FLUSH_DELALLOC:
4211         case FLUSH_DELALLOC_WAIT:
4212                 shrink_delalloc(root, num_bytes, orig_bytes,
4213                                 state == FLUSH_DELALLOC_WAIT);
4214                 break;
4215         case ALLOC_CHUNK:
4216                 trans = btrfs_join_transaction(root);
4217                 if (IS_ERR(trans)) {
4218                         ret = PTR_ERR(trans);
4219                         break;
4220                 }
4221                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
4222                                      btrfs_get_alloc_profile(root, 0),
4223                                      CHUNK_ALLOC_NO_FORCE);
4224                 btrfs_end_transaction(trans, root);
4225                 if (ret == -ENOSPC)
4226                         ret = 0;
4227                 break;
4228         case COMMIT_TRANS:
4229                 ret = may_commit_transaction(root, space_info, orig_bytes, 0);
4230                 break;
4231         default:
4232                 ret = -ENOSPC;
4233                 break;
4234         }
4235
4236         return ret;
4237 }
4238 /**
4239  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
4240  * @root - the root we're allocating for
4241  * @block_rsv - the block_rsv we're allocating for
4242  * @orig_bytes - the number of bytes we want
4243  * @flush - whether or not we can flush to make our reservation
4244  *
4245  * This will reserve orgi_bytes number of bytes from the space info associated
4246  * with the block_rsv.  If there is not enough space it will make an attempt to
4247  * flush out space to make room.  It will do this by flushing delalloc if
4248  * possible or committing the transaction.  If flush is 0 then no attempts to
4249  * regain reservations will be made and this will fail if there is not enough
4250  * space already.
4251  */
4252 static int reserve_metadata_bytes(struct btrfs_root *root,
4253                                   struct btrfs_block_rsv *block_rsv,
4254                                   u64 orig_bytes,
4255                                   enum btrfs_reserve_flush_enum flush)
4256 {
4257         struct btrfs_space_info *space_info = block_rsv->space_info;
4258         u64 used;
4259         u64 num_bytes = orig_bytes;
4260         int flush_state = FLUSH_DELAYED_ITEMS_NR;
4261         int ret = 0;
4262         bool flushing = false;
4263
4264 again:
4265         ret = 0;
4266         spin_lock(&space_info->lock);
4267         /*
4268          * We only want to wait if somebody other than us is flushing and we
4269          * are actually allowed to flush all things.
4270          */
4271         while (flush == BTRFS_RESERVE_FLUSH_ALL && !flushing &&
4272                space_info->flush) {
4273                 spin_unlock(&space_info->lock);
4274                 /*
4275                  * If we have a trans handle we can't wait because the flusher
4276                  * may have to commit the transaction, which would mean we would
4277                  * deadlock since we are waiting for the flusher to finish, but
4278                  * hold the current transaction open.
4279                  */
4280                 if (current->journal_info)
4281                         return -EAGAIN;
4282                 ret = wait_event_killable(space_info->wait, !space_info->flush);
4283                 /* Must have been killed, return */
4284                 if (ret)
4285                         return -EINTR;
4286
4287                 spin_lock(&space_info->lock);
4288         }
4289
4290         ret = -ENOSPC;
4291         used = space_info->bytes_used + space_info->bytes_reserved +
4292                 space_info->bytes_pinned + space_info->bytes_readonly +
4293                 space_info->bytes_may_use;
4294
4295         /*
4296          * The idea here is that we've not already over-reserved the block group
4297          * then we can go ahead and save our reservation first and then start
4298          * flushing if we need to.  Otherwise if we've already overcommitted
4299          * lets start flushing stuff first and then come back and try to make
4300          * our reservation.
4301          */
4302         if (used <= space_info->total_bytes) {
4303                 if (used + orig_bytes <= space_info->total_bytes) {
4304                         space_info->bytes_may_use += orig_bytes;
4305                         trace_btrfs_space_reservation(root->fs_info,
4306                                 "space_info", space_info->flags, orig_bytes, 1);
4307                         ret = 0;
4308                 } else {
4309                         /*
4310                          * Ok set num_bytes to orig_bytes since we aren't
4311                          * overocmmitted, this way we only try and reclaim what
4312                          * we need.
4313                          */
4314                         num_bytes = orig_bytes;
4315                 }
4316         } else {
4317                 /*
4318                  * Ok we're over committed, set num_bytes to the overcommitted
4319                  * amount plus the amount of bytes that we need for this
4320                  * reservation.
4321                  */
4322                 num_bytes = used - space_info->total_bytes +
4323                         (orig_bytes * 2);
4324         }
4325
4326         if (ret && can_overcommit(root, space_info, orig_bytes, flush)) {
4327                 space_info->bytes_may_use += orig_bytes;
4328                 trace_btrfs_space_reservation(root->fs_info, "space_info",
4329                                               space_info->flags, orig_bytes,
4330                                               1);
4331                 ret = 0;
4332         }
4333
4334         /*
4335          * Couldn't make our reservation, save our place so while we're trying
4336          * to reclaim space we can actually use it instead of somebody else
4337          * stealing it from us.
4338          *
4339          * We make the other tasks wait for the flush only when we can flush
4340          * all things.
4341          */
4342         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
4343                 flushing = true;
4344                 space_info->flush = 1;
4345         }
4346
4347         spin_unlock(&space_info->lock);
4348
4349         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
4350                 goto out;
4351
4352         ret = flush_space(root, space_info, num_bytes, orig_bytes,
4353                           flush_state);
4354         flush_state++;
4355
4356         /*
4357          * If we are FLUSH_LIMIT, we can not flush delalloc, or the deadlock
4358          * would happen. So skip delalloc flush.
4359          */
4360         if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4361             (flush_state == FLUSH_DELALLOC ||
4362              flush_state == FLUSH_DELALLOC_WAIT))
4363                 flush_state = ALLOC_CHUNK;
4364
4365         if (!ret)
4366                 goto again;
4367         else if (flush == BTRFS_RESERVE_FLUSH_LIMIT &&
4368                  flush_state < COMMIT_TRANS)
4369                 goto again;
4370         else if (flush == BTRFS_RESERVE_FLUSH_ALL &&
4371                  flush_state <= COMMIT_TRANS)
4372                 goto again;
4373
4374 out:
4375         if (ret == -ENOSPC &&
4376             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
4377                 struct btrfs_block_rsv *global_rsv =
4378                         &root->fs_info->global_block_rsv;
4379
4380                 if (block_rsv != global_rsv &&
4381                     !block_rsv_use_bytes(global_rsv, orig_bytes))
4382                         ret = 0;
4383         }
4384         if (ret == -ENOSPC)
4385                 trace_btrfs_space_reservation(root->fs_info,
4386                                               "space_info:enospc",
4387                                               space_info->flags, orig_bytes, 1);
4388         if (flushing) {
4389                 spin_lock(&space_info->lock);
4390                 space_info->flush = 0;
4391                 wake_up_all(&space_info->wait);
4392                 spin_unlock(&space_info->lock);
4393         }
4394         return ret;
4395 }
4396
4397 static struct btrfs_block_rsv *get_block_rsv(
4398                                         const struct btrfs_trans_handle *trans,
4399                                         const struct btrfs_root *root)
4400 {
4401         struct btrfs_block_rsv *block_rsv = NULL;
4402
4403         if (root->ref_cows)
4404                 block_rsv = trans->block_rsv;
4405
4406         if (root == root->fs_info->csum_root && trans->adding_csums)
4407                 block_rsv = trans->block_rsv;
4408
4409         if (root == root->fs_info->uuid_root)
4410                 block_rsv = trans->block_rsv;
4411
4412         if (!block_rsv)
4413                 block_rsv = root->block_rsv;
4414
4415         if (!block_rsv)
4416                 block_rsv = &root->fs_info->empty_block_rsv;
4417
4418         return block_rsv;
4419 }
4420
4421 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
4422                                u64 num_bytes)
4423 {
4424         int ret = -ENOSPC;
4425         spin_lock(&block_rsv->lock);
4426         if (block_rsv->reserved >= num_bytes) {
4427                 block_rsv->reserved -= num_bytes;
4428                 if (block_rsv->reserved < block_rsv->size)
4429                         block_rsv->full = 0;
4430                 ret = 0;
4431         }
4432         spin_unlock(&block_rsv->lock);
4433         return ret;
4434 }
4435
4436 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
4437                                 u64 num_bytes, int update_size)
4438 {
4439         spin_lock(&block_rsv->lock);
4440         block_rsv->reserved += num_bytes;
4441         if (update_size)
4442                 block_rsv->size += num_bytes;
4443         else if (block_rsv->reserved >= block_rsv->size)
4444                 block_rsv->full = 1;
4445         spin_unlock(&block_rsv->lock);
4446 }
4447
4448 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
4449                              struct btrfs_block_rsv *dest, u64 num_bytes,
4450                              int min_factor)
4451 {
4452         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4453         u64 min_bytes;
4454
4455         if (global_rsv->space_info != dest->space_info)
4456                 return -ENOSPC;
4457
4458         spin_lock(&global_rsv->lock);
4459         min_bytes = div_factor(global_rsv->size, min_factor);
4460         if (global_rsv->reserved < min_bytes + num_bytes) {
4461                 spin_unlock(&global_rsv->lock);
4462                 return -ENOSPC;
4463         }
4464         global_rsv->reserved -= num_bytes;
4465         if (global_rsv->reserved < global_rsv->size)
4466                 global_rsv->full = 0;
4467         spin_unlock(&global_rsv->lock);
4468
4469         block_rsv_add_bytes(dest, num_bytes, 1);
4470         return 0;
4471 }
4472
4473 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
4474                                     struct btrfs_block_rsv *block_rsv,
4475                                     struct btrfs_block_rsv *dest, u64 num_bytes)
4476 {
4477         struct btrfs_space_info *space_info = block_rsv->space_info;
4478
4479         spin_lock(&block_rsv->lock);
4480         if (num_bytes == (u64)-1)
4481                 num_bytes = block_rsv->size;
4482         block_rsv->size -= num_bytes;
4483         if (block_rsv->reserved >= block_rsv->size) {
4484                 num_bytes = block_rsv->reserved - block_rsv->size;
4485                 block_rsv->reserved = block_rsv->size;
4486                 block_rsv->full = 1;
4487         } else {
4488                 num_bytes = 0;
4489         }
4490         spin_unlock(&block_rsv->lock);
4491
4492         if (num_bytes > 0) {
4493                 if (dest) {
4494                         spin_lock(&dest->lock);
4495                         if (!dest->full) {
4496                                 u64 bytes_to_add;
4497
4498                                 bytes_to_add = dest->size - dest->reserved;
4499                                 bytes_to_add = min(num_bytes, bytes_to_add);
4500                                 dest->reserved += bytes_to_add;
4501                                 if (dest->reserved >= dest->size)
4502                                         dest->full = 1;
4503                                 num_bytes -= bytes_to_add;
4504                         }
4505                         spin_unlock(&dest->lock);
4506                 }
4507                 if (num_bytes) {
4508                         spin_lock(&space_info->lock);
4509                         space_info->bytes_may_use -= num_bytes;
4510                         trace_btrfs_space_reservation(fs_info, "space_info",
4511                                         space_info->flags, num_bytes, 0);
4512                         spin_unlock(&space_info->lock);
4513                 }
4514         }
4515 }
4516
4517 static int block_rsv_migrate_bytes(struct btrfs_block_rsv *src,
4518                                    struct btrfs_block_rsv *dst, u64 num_bytes)
4519 {
4520         int ret;
4521
4522         ret = block_rsv_use_bytes(src, num_bytes);
4523         if (ret)
4524                 return ret;
4525
4526         block_rsv_add_bytes(dst, num_bytes, 1);
4527         return 0;
4528 }
4529
4530 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
4531 {
4532         memset(rsv, 0, sizeof(*rsv));
4533         spin_lock_init(&rsv->lock);
4534         rsv->type = type;
4535 }
4536
4537 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_root *root,
4538                                               unsigned short type)
4539 {
4540         struct btrfs_block_rsv *block_rsv;
4541         struct btrfs_fs_info *fs_info = root->fs_info;
4542
4543         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
4544         if (!block_rsv)
4545                 return NULL;
4546
4547         btrfs_init_block_rsv(block_rsv, type);
4548         block_rsv->space_info = __find_space_info(fs_info,
4549                                                   BTRFS_BLOCK_GROUP_METADATA);
4550         return block_rsv;
4551 }
4552
4553 void btrfs_free_block_rsv(struct btrfs_root *root,
4554                           struct btrfs_block_rsv *rsv)
4555 {
4556         if (!rsv)
4557                 return;
4558         btrfs_block_rsv_release(root, rsv, (u64)-1);
4559         kfree(rsv);
4560 }
4561
4562 int btrfs_block_rsv_add(struct btrfs_root *root,
4563                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
4564                         enum btrfs_reserve_flush_enum flush)
4565 {
4566         int ret;
4567
4568         if (num_bytes == 0)
4569                 return 0;
4570
4571         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4572         if (!ret) {
4573                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
4574                 return 0;
4575         }
4576
4577         return ret;
4578 }
4579
4580 int btrfs_block_rsv_check(struct btrfs_root *root,
4581                           struct btrfs_block_rsv *block_rsv, int min_factor)
4582 {
4583         u64 num_bytes = 0;
4584         int ret = -ENOSPC;
4585
4586         if (!block_rsv)
4587                 return 0;
4588
4589         spin_lock(&block_rsv->lock);
4590         num_bytes = div_factor(block_rsv->size, min_factor);
4591         if (block_rsv->reserved >= num_bytes)
4592                 ret = 0;
4593         spin_unlock(&block_rsv->lock);
4594
4595         return ret;
4596 }
4597
4598 int btrfs_block_rsv_refill(struct btrfs_root *root,
4599                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
4600                            enum btrfs_reserve_flush_enum flush)
4601 {
4602         u64 num_bytes = 0;
4603         int ret = -ENOSPC;
4604
4605         if (!block_rsv)
4606                 return 0;
4607
4608         spin_lock(&block_rsv->lock);
4609         num_bytes = min_reserved;
4610         if (block_rsv->reserved >= num_bytes)
4611                 ret = 0;
4612         else
4613                 num_bytes -= block_rsv->reserved;
4614         spin_unlock(&block_rsv->lock);
4615
4616         if (!ret)
4617                 return 0;
4618
4619         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
4620         if (!ret) {
4621                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
4622                 return 0;
4623         }
4624
4625         return ret;
4626 }
4627
4628 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src_rsv,
4629                             struct btrfs_block_rsv *dst_rsv,
4630                             u64 num_bytes)
4631 {
4632         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4633 }
4634
4635 void btrfs_block_rsv_release(struct btrfs_root *root,
4636                              struct btrfs_block_rsv *block_rsv,
4637                              u64 num_bytes)
4638 {
4639         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4640         if (global_rsv->full || global_rsv == block_rsv ||
4641             block_rsv->space_info != global_rsv->space_info)
4642                 global_rsv = NULL;
4643         block_rsv_release_bytes(root->fs_info, block_rsv, global_rsv,
4644                                 num_bytes);
4645 }
4646
4647 /*
4648  * helper to calculate size of global block reservation.
4649  * the desired value is sum of space used by extent tree,
4650  * checksum tree and root tree
4651  */
4652 static u64 calc_global_metadata_size(struct btrfs_fs_info *fs_info)
4653 {
4654         struct btrfs_space_info *sinfo;
4655         u64 num_bytes;
4656         u64 meta_used;
4657         u64 data_used;
4658         int csum_size = btrfs_super_csum_size(fs_info->super_copy);
4659
4660         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_DATA);
4661         spin_lock(&sinfo->lock);
4662         data_used = sinfo->bytes_used;
4663         spin_unlock(&sinfo->lock);
4664
4665         sinfo = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4666         spin_lock(&sinfo->lock);
4667         if (sinfo->flags & BTRFS_BLOCK_GROUP_DATA)
4668                 data_used = 0;
4669         meta_used = sinfo->bytes_used;
4670         spin_unlock(&sinfo->lock);
4671
4672         num_bytes = (data_used >> fs_info->sb->s_blocksize_bits) *
4673                     csum_size * 2;
4674         num_bytes += div64_u64(data_used + meta_used, 50);
4675
4676         if (num_bytes * 3 > meta_used)
4677                 num_bytes = div64_u64(meta_used, 3);
4678
4679         return ALIGN(num_bytes, fs_info->extent_root->leafsize << 10);
4680 }
4681
4682 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
4683 {
4684         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
4685         struct btrfs_space_info *sinfo = block_rsv->space_info;
4686         u64 num_bytes;
4687
4688         num_bytes = calc_global_metadata_size(fs_info);
4689
4690         spin_lock(&sinfo->lock);
4691         spin_lock(&block_rsv->lock);
4692
4693         block_rsv->size = min_t(u64, num_bytes, 512 * 1024 * 1024);
4694
4695         num_bytes = sinfo->bytes_used + sinfo->bytes_pinned +
4696                     sinfo->bytes_reserved + sinfo->bytes_readonly +
4697                     sinfo->bytes_may_use;
4698
4699         if (sinfo->total_bytes > num_bytes) {
4700                 num_bytes = sinfo->total_bytes - num_bytes;
4701                 block_rsv->reserved += num_bytes;
4702                 sinfo->bytes_may_use += num_bytes;
4703                 trace_btrfs_space_reservation(fs_info, "space_info",
4704                                       sinfo->flags, num_bytes, 1);
4705         }
4706
4707         if (block_rsv->reserved >= block_rsv->size) {
4708                 num_bytes = block_rsv->reserved - block_rsv->size;
4709                 sinfo->bytes_may_use -= num_bytes;
4710                 trace_btrfs_space_reservation(fs_info, "space_info",
4711                                       sinfo->flags, num_bytes, 0);
4712                 block_rsv->reserved = block_rsv->size;
4713                 block_rsv->full = 1;
4714         }
4715
4716         spin_unlock(&block_rsv->lock);
4717         spin_unlock(&sinfo->lock);
4718 }
4719
4720 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
4721 {
4722         struct btrfs_space_info *space_info;
4723
4724         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4725         fs_info->chunk_block_rsv.space_info = space_info;
4726
4727         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4728         fs_info->global_block_rsv.space_info = space_info;
4729         fs_info->delalloc_block_rsv.space_info = space_info;
4730         fs_info->trans_block_rsv.space_info = space_info;
4731         fs_info->empty_block_rsv.space_info = space_info;
4732         fs_info->delayed_block_rsv.space_info = space_info;
4733
4734         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
4735         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
4736         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
4737         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
4738         if (fs_info->quota_root)
4739                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
4740         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
4741
4742         update_global_block_rsv(fs_info);
4743 }
4744
4745 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
4746 {
4747         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
4748                                 (u64)-1);
4749         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
4750         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
4751         WARN_ON(fs_info->trans_block_rsv.size > 0);
4752         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
4753         WARN_ON(fs_info->chunk_block_rsv.size > 0);
4754         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
4755         WARN_ON(fs_info->delayed_block_rsv.size > 0);
4756         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
4757 }
4758
4759 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
4760                                   struct btrfs_root *root)
4761 {
4762         if (!trans->block_rsv)
4763                 return;
4764
4765         if (!trans->bytes_reserved)
4766                 return;
4767
4768         trace_btrfs_space_reservation(root->fs_info, "transaction",
4769                                       trans->transid, trans->bytes_reserved, 0);
4770         btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
4771         trans->bytes_reserved = 0;
4772 }
4773
4774 /* Can only return 0 or -ENOSPC */
4775 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
4776                                   struct inode *inode)
4777 {
4778         struct btrfs_root *root = BTRFS_I(inode)->root;
4779         struct btrfs_block_rsv *src_rsv = get_block_rsv(trans, root);
4780         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
4781
4782         /*
4783          * We need to hold space in order to delete our orphan item once we've
4784          * added it, so this takes the reservation so we can release it later
4785          * when we are truly done with the orphan item.
4786          */
4787         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4788         trace_btrfs_space_reservation(root->fs_info, "orphan",
4789                                       btrfs_ino(inode), num_bytes, 1);
4790         return block_rsv_migrate_bytes(src_rsv, dst_rsv, num_bytes);
4791 }
4792
4793 void btrfs_orphan_release_metadata(struct inode *inode)
4794 {
4795         struct btrfs_root *root = BTRFS_I(inode)->root;
4796         u64 num_bytes = btrfs_calc_trans_metadata_size(root, 1);
4797         trace_btrfs_space_reservation(root->fs_info, "orphan",
4798                                       btrfs_ino(inode), num_bytes, 0);
4799         btrfs_block_rsv_release(root, root->orphan_block_rsv, num_bytes);
4800 }
4801
4802 /*
4803  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
4804  * root: the root of the parent directory
4805  * rsv: block reservation
4806  * items: the number of items that we need do reservation
4807  * qgroup_reserved: used to return the reserved size in qgroup
4808  *
4809  * This function is used to reserve the space for snapshot/subvolume
4810  * creation and deletion. Those operations are different with the
4811  * common file/directory operations, they change two fs/file trees
4812  * and root tree, the number of items that the qgroup reserves is
4813  * different with the free space reservation. So we can not use
4814  * the space reseravtion mechanism in start_transaction().
4815  */
4816 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
4817                                      struct btrfs_block_rsv *rsv,
4818                                      int items,
4819                                      u64 *qgroup_reserved,
4820                                      bool use_global_rsv)
4821 {
4822         u64 num_bytes;
4823         int ret;
4824         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
4825
4826         if (root->fs_info->quota_enabled) {
4827                 /* One for parent inode, two for dir entries */
4828                 num_bytes = 3 * root->leafsize;
4829                 ret = btrfs_qgroup_reserve(root, num_bytes);
4830                 if (ret)
4831                         return ret;
4832         } else {
4833                 num_bytes = 0;
4834         }
4835
4836         *qgroup_reserved = num_bytes;
4837
4838         num_bytes = btrfs_calc_trans_metadata_size(root, items);
4839         rsv->space_info = __find_space_info(root->fs_info,
4840                                             BTRFS_BLOCK_GROUP_METADATA);
4841         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
4842                                   BTRFS_RESERVE_FLUSH_ALL);
4843
4844         if (ret == -ENOSPC && use_global_rsv)
4845                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes);
4846
4847         if (ret) {
4848                 if (*qgroup_reserved)
4849                         btrfs_qgroup_free(root, *qgroup_reserved);
4850         }
4851
4852         return ret;
4853 }
4854
4855 void btrfs_subvolume_release_metadata(struct btrfs_root *root,
4856                                       struct btrfs_block_rsv *rsv,
4857                                       u64 qgroup_reserved)
4858 {
4859         btrfs_block_rsv_release(root, rsv, (u64)-1);
4860         if (qgroup_reserved)
4861                 btrfs_qgroup_free(root, qgroup_reserved);
4862 }
4863
4864 /**
4865  * drop_outstanding_extent - drop an outstanding extent
4866  * @inode: the inode we're dropping the extent for
4867  *
4868  * This is called when we are freeing up an outstanding extent, either called
4869  * after an error or after an extent is written.  This will return the number of
4870  * reserved extents that need to be freed.  This must be called with
4871  * BTRFS_I(inode)->lock held.
4872  */
4873 static unsigned drop_outstanding_extent(struct inode *inode)
4874 {
4875         unsigned drop_inode_space = 0;
4876         unsigned dropped_extents = 0;
4877
4878         BUG_ON(!BTRFS_I(inode)->outstanding_extents);
4879         BTRFS_I(inode)->outstanding_extents--;
4880
4881         if (BTRFS_I(inode)->outstanding_extents == 0 &&
4882             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
4883                                &BTRFS_I(inode)->runtime_flags))
4884                 drop_inode_space = 1;
4885
4886         /*
4887          * If we have more or the same amount of outsanding extents than we have
4888          * reserved then we need to leave the reserved extents count alone.
4889          */
4890         if (BTRFS_I(inode)->outstanding_extents >=
4891             BTRFS_I(inode)->reserved_extents)
4892                 return drop_inode_space;
4893
4894         dropped_extents = BTRFS_I(inode)->reserved_extents -
4895                 BTRFS_I(inode)->outstanding_extents;
4896         BTRFS_I(inode)->reserved_extents -= dropped_extents;
4897         return dropped_extents + drop_inode_space;
4898 }
4899
4900 /**
4901  * calc_csum_metadata_size - return the amount of metada space that must be
4902  *      reserved/free'd for the given bytes.
4903  * @inode: the inode we're manipulating
4904  * @num_bytes: the number of bytes in question
4905  * @reserve: 1 if we are reserving space, 0 if we are freeing space
4906  *
4907  * This adjusts the number of csum_bytes in the inode and then returns the
4908  * correct amount of metadata that must either be reserved or freed.  We
4909  * calculate how many checksums we can fit into one leaf and then divide the
4910  * number of bytes that will need to be checksumed by this value to figure out
4911  * how many checksums will be required.  If we are adding bytes then the number
4912  * may go up and we will return the number of additional bytes that must be
4913  * reserved.  If it is going down we will return the number of bytes that must
4914  * be freed.
4915  *
4916  * This must be called with BTRFS_I(inode)->lock held.
4917  */
4918 static u64 calc_csum_metadata_size(struct inode *inode, u64 num_bytes,
4919                                    int reserve)
4920 {
4921         struct btrfs_root *root = BTRFS_I(inode)->root;
4922         u64 csum_size;
4923         int num_csums_per_leaf;
4924         int num_csums;
4925         int old_csums;
4926
4927         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM &&
4928             BTRFS_I(inode)->csum_bytes == 0)
4929                 return 0;
4930
4931         old_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4932         if (reserve)
4933                 BTRFS_I(inode)->csum_bytes += num_bytes;
4934         else
4935                 BTRFS_I(inode)->csum_bytes -= num_bytes;
4936         csum_size = BTRFS_LEAF_DATA_SIZE(root) - sizeof(struct btrfs_item);
4937         num_csums_per_leaf = (int)div64_u64(csum_size,
4938                                             sizeof(struct btrfs_csum_item) +
4939                                             sizeof(struct btrfs_disk_key));
4940         num_csums = (int)div64_u64(BTRFS_I(inode)->csum_bytes, root->sectorsize);
4941         num_csums = num_csums + num_csums_per_leaf - 1;
4942         num_csums = num_csums / num_csums_per_leaf;
4943
4944         old_csums = old_csums + num_csums_per_leaf - 1;
4945         old_csums = old_csums / num_csums_per_leaf;
4946
4947         /* No change, no need to reserve more */
4948         if (old_csums == num_csums)
4949                 return 0;
4950
4951         if (reserve)
4952                 return btrfs_calc_trans_metadata_size(root,
4953                                                       num_csums - old_csums);
4954
4955         return btrfs_calc_trans_metadata_size(root, old_csums - num_csums);
4956 }
4957
4958 int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
4959 {
4960         struct btrfs_root *root = BTRFS_I(inode)->root;
4961         struct btrfs_block_rsv *block_rsv = &root->fs_info->delalloc_block_rsv;
4962         u64 to_reserve = 0;
4963         u64 csum_bytes;
4964         unsigned nr_extents = 0;
4965         int extra_reserve = 0;
4966         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
4967         int ret = 0;
4968         bool delalloc_lock = true;
4969         u64 to_free = 0;
4970         unsigned dropped;
4971
4972         /* If we are a free space inode we need to not flush since we will be in
4973          * the middle of a transaction commit.  We also don't need the delalloc
4974          * mutex since we won't race with anybody.  We need this mostly to make
4975          * lockdep shut its filthy mouth.
4976          */
4977         if (btrfs_is_free_space_inode(inode)) {
4978                 flush = BTRFS_RESERVE_NO_FLUSH;
4979                 delalloc_lock = false;
4980         }
4981
4982         if (flush != BTRFS_RESERVE_NO_FLUSH &&
4983             btrfs_transaction_in_commit(root->fs_info))
4984                 schedule_timeout(1);
4985
4986         if (delalloc_lock)
4987                 mutex_lock(&BTRFS_I(inode)->delalloc_mutex);
4988
4989         num_bytes = ALIGN(num_bytes, root->sectorsize);
4990
4991         spin_lock(&BTRFS_I(inode)->lock);
4992         BTRFS_I(inode)->outstanding_extents++;
4993
4994         if (BTRFS_I(inode)->outstanding_extents >
4995             BTRFS_I(inode)->reserved_extents)
4996                 nr_extents = BTRFS_I(inode)->outstanding_extents -
4997                         BTRFS_I(inode)->reserved_extents;
4998
4999         /*
5000          * Add an item to reserve for updating the inode when we complete the
5001          * delalloc io.
5002          */
5003         if (!test_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5004                       &BTRFS_I(inode)->runtime_flags)) {
5005                 nr_extents++;
5006                 extra_reserve = 1;
5007         }
5008
5009         to_reserve = btrfs_calc_trans_metadata_size(root, nr_extents);
5010         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
5011         csum_bytes = BTRFS_I(inode)->csum_bytes;
5012         spin_unlock(&BTRFS_I(inode)->lock);
5013
5014         if (root->fs_info->quota_enabled) {
5015                 ret = btrfs_qgroup_reserve(root, num_bytes +
5016                                            nr_extents * root->leafsize);
5017                 if (ret)
5018                         goto out_fail;
5019         }
5020
5021         ret = reserve_metadata_bytes(root, block_rsv, to_reserve, flush);
5022         if (unlikely(ret)) {
5023                 if (root->fs_info->quota_enabled)
5024                         btrfs_qgroup_free(root, num_bytes +
5025                                                 nr_extents * root->leafsize);
5026                 goto out_fail;
5027         }
5028
5029         spin_lock(&BTRFS_I(inode)->lock);
5030         if (extra_reserve) {
5031                 set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
5032                         &BTRFS_I(inode)->runtime_flags);
5033                 nr_extents--;
5034         }
5035         BTRFS_I(inode)->reserved_extents += nr_extents;
5036         spin_unlock(&BTRFS_I(inode)->lock);
5037
5038         if (delalloc_lock)
5039                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5040
5041         if (to_reserve)
5042                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5043                                               btrfs_ino(inode), to_reserve, 1);
5044         block_rsv_add_bytes(block_rsv, to_reserve, 1);
5045
5046         return 0;
5047
5048 out_fail:
5049         spin_lock(&BTRFS_I(inode)->lock);
5050         dropped = drop_outstanding_extent(inode);
5051         /*
5052          * If the inodes csum_bytes is the same as the original
5053          * csum_bytes then we know we haven't raced with any free()ers
5054          * so we can just reduce our inodes csum bytes and carry on.
5055          */
5056         if (BTRFS_I(inode)->csum_bytes == csum_bytes) {
5057                 calc_csum_metadata_size(inode, num_bytes, 0);
5058         } else {
5059                 u64 orig_csum_bytes = BTRFS_I(inode)->csum_bytes;
5060                 u64 bytes;
5061
5062                 /*
5063                  * This is tricky, but first we need to figure out how much we
5064                  * free'd from any free-ers that occured during this
5065                  * reservation, so we reset ->csum_bytes to the csum_bytes
5066                  * before we dropped our lock, and then call the free for the
5067                  * number of bytes that were freed while we were trying our
5068                  * reservation.
5069                  */
5070                 bytes = csum_bytes - BTRFS_I(inode)->csum_bytes;
5071                 BTRFS_I(inode)->csum_bytes = csum_bytes;
5072                 to_free = calc_csum_metadata_size(inode, bytes, 0);
5073
5074
5075                 /*
5076                  * Now we need to see how much we would have freed had we not
5077                  * been making this reservation and our ->csum_bytes were not
5078                  * artificially inflated.
5079                  */
5080                 BTRFS_I(inode)->csum_bytes = csum_bytes - num_bytes;
5081                 bytes = csum_bytes - orig_csum_bytes;
5082                 bytes = calc_csum_metadata_size(inode, bytes, 0);
5083
5084                 /*
5085                  * Now reset ->csum_bytes to what it should be.  If bytes is
5086                  * more than to_free then we would have free'd more space had we
5087                  * not had an artificially high ->csum_bytes, so we need to free
5088                  * the remainder.  If bytes is the same or less then we don't
5089                  * need to do anything, the other free-ers did the correct
5090                  * thing.
5091                  */
5092                 BTRFS_I(inode)->csum_bytes = orig_csum_bytes - num_bytes;
5093                 if (bytes > to_free)
5094                         to_free = bytes - to_free;
5095                 else
5096                         to_free = 0;
5097         }
5098         spin_unlock(&BTRFS_I(inode)->lock);
5099         if (dropped)
5100                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5101
5102         if (to_free) {
5103                 btrfs_block_rsv_release(root, block_rsv, to_free);
5104                 trace_btrfs_space_reservation(root->fs_info, "delalloc",
5105                                               btrfs_ino(inode), to_free, 0);
5106         }
5107         if (delalloc_lock)
5108                 mutex_unlock(&BTRFS_I(inode)->delalloc_mutex);
5109         return ret;
5110 }
5111
5112 /**
5113  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
5114  * @inode: the inode to release the reservation for
5115  * @num_bytes: the number of bytes we're releasing
5116  *
5117  * This will release the metadata reservation for an inode.  This can be called
5118  * once we complete IO for a given set of bytes to release their metadata
5119  * reservations.
5120  */
5121 void btrfs_delalloc_release_metadata(struct inode *inode, u64 num_bytes)
5122 {
5123         struct btrfs_root *root = BTRFS_I(inode)->root;
5124         u64 to_free = 0;
5125         unsigned dropped;
5126
5127         num_bytes = ALIGN(num_bytes, root->sectorsize);
5128         spin_lock(&BTRFS_I(inode)->lock);
5129         dropped = drop_outstanding_extent(inode);
5130
5131         if (num_bytes)
5132                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
5133         spin_unlock(&BTRFS_I(inode)->lock);
5134         if (dropped > 0)
5135                 to_free += btrfs_calc_trans_metadata_size(root, dropped);
5136
5137         trace_btrfs_space_reservation(root->fs_info, "delalloc",
5138                                       btrfs_ino(inode), to_free, 0);
5139         if (root->fs_info->quota_enabled) {
5140                 btrfs_qgroup_free(root, num_bytes +
5141                                         dropped * root->leafsize);
5142         }
5143
5144         btrfs_block_rsv_release(root, &root->fs_info->delalloc_block_rsv,
5145                                 to_free);
5146 }
5147
5148 /**
5149  * btrfs_delalloc_reserve_space - reserve data and metadata space for delalloc
5150  * @inode: inode we're writing to
5151  * @num_bytes: the number of bytes we want to allocate
5152  *
5153  * This will do the following things
5154  *
5155  * o reserve space in the data space info for num_bytes
5156  * o reserve space in the metadata space info based on number of outstanding
5157  *   extents and how much csums will be needed
5158  * o add to the inodes ->delalloc_bytes
5159  * o add it to the fs_info's delalloc inodes list.
5160  *
5161  * This will return 0 for success and -ENOSPC if there is no space left.
5162  */
5163 int btrfs_delalloc_reserve_space(struct inode *inode, u64 num_bytes)
5164 {
5165         int ret;
5166
5167         ret = btrfs_check_data_free_space(inode, num_bytes);
5168         if (ret)
5169                 return ret;
5170
5171         ret = btrfs_delalloc_reserve_metadata(inode, num_bytes);
5172         if (ret) {
5173                 btrfs_free_reserved_data_space(inode, num_bytes);
5174                 return ret;
5175         }
5176
5177         return 0;
5178 }
5179
5180 /**
5181  * btrfs_delalloc_release_space - release data and metadata space for delalloc
5182  * @inode: inode we're releasing space for
5183  * @num_bytes: the number of bytes we want to free up
5184  *
5185  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
5186  * called in the case that we don't need the metadata AND data reservations
5187  * anymore.  So if there is an error or we insert an inline extent.
5188  *
5189  * This function will release the metadata space that was not used and will
5190  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
5191  * list if there are no delalloc bytes left.
5192  */
5193 void btrfs_delalloc_release_space(struct inode *inode, u64 num_bytes)
5194 {
5195         btrfs_delalloc_release_metadata(inode, num_bytes);
5196         btrfs_free_reserved_data_space(inode, num_bytes);
5197 }
5198
5199 static int update_block_group(struct btrfs_root *root,
5200                               u64 bytenr, u64 num_bytes, int alloc)
5201 {
5202         struct btrfs_block_group_cache *cache = NULL;
5203         struct btrfs_fs_info *info = root->fs_info;
5204         u64 total = num_bytes;
5205         u64 old_val;
5206         u64 byte_in_group;
5207         int factor;
5208
5209         /* block accounting for super block */
5210         spin_lock(&info->delalloc_root_lock);
5211         old_val = btrfs_super_bytes_used(info->super_copy);
5212         if (alloc)
5213                 old_val += num_bytes;
5214         else
5215                 old_val -= num_bytes;
5216         btrfs_set_super_bytes_used(info->super_copy, old_val);
5217         spin_unlock(&info->delalloc_root_lock);
5218
5219         while (total) {
5220                 cache = btrfs_lookup_block_group(info, bytenr);
5221                 if (!cache)
5222                         return -ENOENT;
5223                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
5224                                     BTRFS_BLOCK_GROUP_RAID1 |
5225                                     BTRFS_BLOCK_GROUP_RAID10))
5226                         factor = 2;
5227                 else
5228                         factor = 1;
5229                 /*
5230                  * If this block group has free space cache written out, we
5231                  * need to make sure to load it if we are removing space.  This
5232                  * is because we need the unpinning stage to actually add the
5233                  * space back to the block group, otherwise we will leak space.
5234                  */
5235                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
5236                         cache_block_group(cache, 1);
5237
5238                 byte_in_group = bytenr - cache->key.objectid;
5239                 WARN_ON(byte_in_group > cache->key.offset);
5240
5241                 spin_lock(&cache->space_info->lock);
5242                 spin_lock(&cache->lock);
5243
5244                 if (btrfs_test_opt(root, SPACE_CACHE) &&
5245                     cache->disk_cache_state < BTRFS_DC_CLEAR)
5246                         cache->disk_cache_state = BTRFS_DC_CLEAR;
5247
5248                 cache->dirty = 1;
5249                 old_val = btrfs_block_group_used(&cache->item);
5250                 num_bytes = min(total, cache->key.offset - byte_in_group);
5251                 if (alloc) {
5252                         old_val += num_bytes;
5253                         btrfs_set_block_group_used(&cache->item, old_val);
5254                         cache->reserved -= num_bytes;
5255                         cache->space_info->bytes_reserved -= num_bytes;
5256                         cache->space_info->bytes_used += num_bytes;
5257                         cache->space_info->disk_used += num_bytes * factor;
5258                         spin_unlock(&cache->lock);
5259                         spin_unlock(&cache->space_info->lock);
5260                 } else {
5261                         old_val -= num_bytes;
5262                         btrfs_set_block_group_used(&cache->item, old_val);
5263                         cache->pinned += num_bytes;
5264                         cache->space_info->bytes_pinned += num_bytes;
5265                         cache->space_info->bytes_used -= num_bytes;
5266                         cache->space_info->disk_used -= num_bytes * factor;
5267                         spin_unlock(&cache->lock);
5268                         spin_unlock(&cache->space_info->lock);
5269
5270                         set_extent_dirty(info->pinned_extents,
5271                                          bytenr, bytenr + num_bytes - 1,
5272                                          GFP_NOFS | __GFP_NOFAIL);
5273                 }
5274                 btrfs_put_block_group(cache);
5275                 total -= num_bytes;
5276                 bytenr += num_bytes;
5277         }
5278         return 0;
5279 }
5280
5281 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
5282 {
5283         struct btrfs_block_group_cache *cache;
5284         u64 bytenr;
5285
5286         spin_lock(&root->fs_info->block_group_cache_lock);
5287         bytenr = root->fs_info->first_logical_byte;
5288         spin_unlock(&root->fs_info->block_group_cache_lock);
5289
5290         if (bytenr < (u64)-1)
5291                 return bytenr;
5292
5293         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
5294         if (!cache)
5295                 return 0;
5296
5297         bytenr = cache->key.objectid;
5298         btrfs_put_block_group(cache);
5299
5300         return bytenr;
5301 }
5302
5303 static int pin_down_extent(struct btrfs_root *root,
5304                            struct btrfs_block_group_cache *cache,
5305                            u64 bytenr, u64 num_bytes, int reserved)
5306 {
5307         spin_lock(&cache->space_info->lock);
5308         spin_lock(&cache->lock);
5309         cache->pinned += num_bytes;
5310         cache->space_info->bytes_pinned += num_bytes;
5311         if (reserved) {
5312                 cache->reserved -= num_bytes;
5313                 cache->space_info->bytes_reserved -= num_bytes;
5314         }
5315         spin_unlock(&cache->lock);
5316         spin_unlock(&cache->space_info->lock);
5317
5318         set_extent_dirty(root->fs_info->pinned_extents, bytenr,
5319                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
5320         if (reserved)
5321                 trace_btrfs_reserved_extent_free(root, bytenr, num_bytes);
5322         return 0;
5323 }
5324
5325 /*
5326  * this function must be called within transaction
5327  */
5328 int btrfs_pin_extent(struct btrfs_root *root,
5329                      u64 bytenr, u64 num_bytes, int reserved)
5330 {
5331         struct btrfs_block_group_cache *cache;
5332
5333         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5334         BUG_ON(!cache); /* Logic error */
5335
5336         pin_down_extent(root, cache, bytenr, num_bytes, reserved);
5337
5338         btrfs_put_block_group(cache);
5339         return 0;
5340 }
5341
5342 /*
5343  * this function must be called within transaction
5344  */
5345 int btrfs_pin_extent_for_log_replay(struct btrfs_root *root,
5346                                     u64 bytenr, u64 num_bytes)
5347 {
5348         struct btrfs_block_group_cache *cache;
5349         int ret;
5350
5351         cache = btrfs_lookup_block_group(root->fs_info, bytenr);
5352         if (!cache)
5353                 return -EINVAL;
5354
5355         /*
5356          * pull in the free space cache (if any) so that our pin
5357          * removes the free space from the cache.  We have load_only set
5358          * to one because the slow code to read in the free extents does check
5359          * the pinned extents.
5360          */
5361         cache_block_group(cache, 1);
5362
5363         pin_down_extent(root, cache, bytenr, num_bytes, 0);
5364
5365         /* remove us from the free space cache (if we're there at all) */
5366         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
5367         btrfs_put_block_group(cache);
5368         return ret;
5369 }
5370
5371 static int __exclude_logged_extent(struct btrfs_root *root, u64 start, u64 num_bytes)
5372 {
5373         int ret;
5374         struct btrfs_block_group_cache *block_group;
5375         struct btrfs_caching_control *caching_ctl;
5376
5377         block_group = btrfs_lookup_block_group(root->fs_info, start);
5378         if (!block_group)
5379                 return -EINVAL;
5380
5381         cache_block_group(block_group, 0);
5382         caching_ctl = get_caching_control(block_group);
5383
5384         if (!caching_ctl) {
5385                 /* Logic error */
5386                 BUG_ON(!block_group_cache_done(block_group));
5387                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
5388         } else {
5389                 mutex_lock(&caching_ctl->mutex);
5390
5391                 if (start >= caching_ctl->progress) {
5392                         ret = add_excluded_extent(root, start, num_bytes);
5393                 } else if (start + num_bytes <= caching_ctl->progress) {
5394                         ret = btrfs_remove_free_space(block_group,
5395                                                       start, num_bytes);
5396                 } else {
5397                         num_bytes = caching_ctl->progress - start;
5398                         ret = btrfs_remove_free_space(block_group,
5399                                                       start, num_bytes);
5400                         if (ret)
5401                                 goto out_lock;
5402
5403                         num_bytes = (start + num_bytes) -
5404                                 caching_ctl->progress;
5405                         start = caching_ctl->progress;
5406                         ret = add_excluded_extent(root, start, num_bytes);
5407                 }
5408 out_lock:
5409                 mutex_unlock(&caching_ctl->mutex);
5410                 put_caching_control(caching_ctl);
5411         }
5412         btrfs_put_block_group(block_group);
5413         return ret;
5414 }
5415
5416 int btrfs_exclude_logged_extents(struct btrfs_root *log,
5417                                  struct extent_buffer *eb)
5418 {
5419         struct btrfs_file_extent_item *item;
5420         struct btrfs_key key;
5421         int found_type;
5422         int i;
5423
5424         if (!btrfs_fs_incompat(log->fs_info, MIXED_GROUPS))
5425                 return 0;
5426
5427         for (i = 0; i < btrfs_header_nritems(eb); i++) {
5428                 btrfs_item_key_to_cpu(eb, &key, i);
5429                 if (key.type != BTRFS_EXTENT_DATA_KEY)
5430                         continue;
5431                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
5432                 found_type = btrfs_file_extent_type(eb, item);
5433                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
5434                         continue;
5435                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
5436                         continue;
5437                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
5438                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
5439                 __exclude_logged_extent(log, key.objectid, key.offset);
5440         }
5441
5442         return 0;
5443 }
5444
5445 /**
5446  * btrfs_update_reserved_bytes - update the block_group and space info counters
5447  * @cache:      The cache we are manipulating
5448  * @num_bytes:  The number of bytes in question
5449  * @reserve:    One of the reservation enums
5450  *
5451  * This is called by the allocator when it reserves space, or by somebody who is
5452  * freeing space that was never actually used on disk.  For example if you
5453  * reserve some space for a new leaf in transaction A and before transaction A
5454  * commits you free that leaf, you call this with reserve set to 0 in order to
5455  * clear the reservation.
5456  *
5457  * Metadata reservations should be called with RESERVE_ALLOC so we do the proper
5458  * ENOSPC accounting.  For data we handle the reservation through clearing the
5459  * delalloc bits in the io_tree.  We have to do this since we could end up
5460  * allocating less disk space for the amount of data we have reserved in the
5461  * case of compression.
5462  *
5463  * If this is a reservation and the block group has become read only we cannot
5464  * make the reservation and return -EAGAIN, otherwise this function always
5465  * succeeds.
5466  */
5467 static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
5468                                        u64 num_bytes, int reserve)
5469 {
5470         struct btrfs_space_info *space_info = cache->space_info;
5471         int ret = 0;
5472
5473         spin_lock(&space_info->lock);
5474         spin_lock(&cache->lock);
5475         if (reserve != RESERVE_FREE) {
5476                 if (cache->ro) {
5477                         ret = -EAGAIN;
5478                 } else {
5479                         cache->reserved += num_bytes;
5480                         space_info->bytes_reserved += num_bytes;
5481                         if (reserve == RESERVE_ALLOC) {
5482                                 trace_btrfs_space_reservation(cache->fs_info,
5483                                                 "space_info", space_info->flags,
5484                                                 num_bytes, 0);
5485                                 space_info->bytes_may_use -= num_bytes;
5486                         }
5487                 }
5488         } else {
5489                 if (cache->ro)
5490                         space_info->bytes_readonly += num_bytes;
5491                 cache->reserved -= num_bytes;
5492                 space_info->bytes_reserved -= num_bytes;
5493         }
5494         spin_unlock(&cache->lock);
5495         spin_unlock(&space_info->lock);
5496         return ret;
5497 }
5498
5499 void btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
5500                                 struct btrfs_root *root)
5501 {
5502         struct btrfs_fs_info *fs_info = root->fs_info;
5503         struct btrfs_caching_control *next;
5504         struct btrfs_caching_control *caching_ctl;
5505         struct btrfs_block_group_cache *cache;
5506         struct btrfs_space_info *space_info;
5507
5508         down_write(&fs_info->extent_commit_sem);
5509
5510         list_for_each_entry_safe(caching_ctl, next,
5511                                  &fs_info->caching_block_groups, list) {
5512                 cache = caching_ctl->block_group;
5513                 if (block_group_cache_done(cache)) {
5514                         cache->last_byte_to_unpin = (u64)-1;
5515                         list_del_init(&caching_ctl->list);
5516                         put_caching_control(caching_ctl);
5517                 } else {
5518                         cache->last_byte_to_unpin = caching_ctl->progress;
5519                 }
5520         }
5521
5522         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5523                 fs_info->pinned_extents = &fs_info->freed_extents[1];
5524         else
5525                 fs_info->pinned_extents = &fs_info->freed_extents[0];
5526
5527         up_write(&fs_info->extent_commit_sem);
5528
5529         list_for_each_entry_rcu(space_info, &fs_info->space_info, list)
5530                 percpu_counter_set(&space_info->total_bytes_pinned, 0);
5531
5532         update_global_block_rsv(fs_info);
5533 }
5534
5535 static int unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
5536 {
5537         struct btrfs_fs_info *fs_info = root->fs_info;
5538         struct btrfs_block_group_cache *cache = NULL;
5539         struct btrfs_space_info *space_info;
5540         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5541         u64 len;
5542         bool readonly;
5543
5544         while (start <= end) {
5545                 readonly = false;
5546                 if (!cache ||
5547                     start >= cache->key.objectid + cache->key.offset) {
5548                         if (cache)
5549                                 btrfs_put_block_group(cache);
5550                         cache = btrfs_lookup_block_group(fs_info, start);
5551                         BUG_ON(!cache); /* Logic error */
5552                 }
5553
5554                 len = cache->key.objectid + cache->key.offset - start;
5555                 len = min(len, end + 1 - start);
5556
5557                 if (start < cache->last_byte_to_unpin) {
5558                         len = min(len, cache->last_byte_to_unpin - start);
5559                         btrfs_add_free_space(cache, start, len);
5560                 }
5561
5562                 start += len;
5563                 space_info = cache->space_info;
5564
5565                 spin_lock(&space_info->lock);
5566                 spin_lock(&cache->lock);
5567                 cache->pinned -= len;
5568                 space_info->bytes_pinned -= len;
5569                 if (cache->ro) {
5570                         space_info->bytes_readonly += len;
5571                         readonly = true;
5572                 }
5573                 spin_unlock(&cache->lock);
5574                 if (!readonly && global_rsv->space_info == space_info) {
5575                         spin_lock(&global_rsv->lock);
5576                         if (!global_rsv->full) {
5577                                 len = min(len, global_rsv->size -
5578                                           global_rsv->reserved);
5579                                 global_rsv->reserved += len;
5580                                 space_info->bytes_may_use += len;
5581                                 if (global_rsv->reserved >= global_rsv->size)
5582                                         global_rsv->full = 1;
5583                         }
5584                         spin_unlock(&global_rsv->lock);
5585                 }
5586                 spin_unlock(&space_info->lock);
5587         }
5588
5589         if (cache)
5590                 btrfs_put_block_group(cache);
5591         return 0;
5592 }
5593
5594 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
5595                                struct btrfs_root *root)
5596 {
5597         struct btrfs_fs_info *fs_info = root->fs_info;
5598         struct extent_io_tree *unpin;
5599         u64 start;
5600         u64 end;
5601         int ret;
5602
5603         if (trans->aborted)
5604                 return 0;
5605
5606         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
5607                 unpin = &fs_info->freed_extents[1];
5608         else
5609                 unpin = &fs_info->freed_extents[0];
5610
5611         while (1) {
5612                 ret = find_first_extent_bit(unpin, 0, &start, &end,
5613                                             EXTENT_DIRTY, NULL);
5614                 if (ret)
5615                         break;
5616
5617                 if (btrfs_test_opt(root, DISCARD))
5618                         ret = btrfs_discard_extent(root, start,
5619                                                    end + 1 - start, NULL);
5620
5621                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
5622                 unpin_extent_range(root, start, end);
5623                 cond_resched();
5624         }
5625
5626         return 0;
5627 }
5628
5629 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, u64 num_bytes,
5630                              u64 owner, u64 root_objectid)
5631 {
5632         struct btrfs_space_info *space_info;
5633         u64 flags;
5634
5635         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
5636                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
5637                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
5638                 else
5639                         flags = BTRFS_BLOCK_GROUP_METADATA;
5640         } else {
5641                 flags = BTRFS_BLOCK_GROUP_DATA;
5642         }
5643
5644         space_info = __find_space_info(fs_info, flags);
5645         BUG_ON(!space_info); /* Logic bug */
5646         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
5647 }
5648
5649
5650 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
5651                                 struct btrfs_root *root,
5652                                 u64 bytenr, u64 num_bytes, u64 parent,
5653                                 u64 root_objectid, u64 owner_objectid,
5654                                 u64 owner_offset, int refs_to_drop,
5655                                 struct btrfs_delayed_extent_op *extent_op)
5656 {
5657         struct btrfs_key key;
5658         struct btrfs_path *path;
5659         struct btrfs_fs_info *info = root->fs_info;
5660         struct btrfs_root *extent_root = info->extent_root;
5661         struct extent_buffer *leaf;
5662         struct btrfs_extent_item *ei;
5663         struct btrfs_extent_inline_ref *iref;
5664         int ret;
5665         int is_data;
5666         int extent_slot = 0;
5667         int found_extent = 0;
5668         int num_to_del = 1;
5669         u32 item_size;
5670         u64 refs;
5671         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
5672                                                  SKINNY_METADATA);
5673
5674         path = btrfs_alloc_path();
5675         if (!path)
5676                 return -ENOMEM;
5677
5678         path->reada = 1;
5679         path->leave_spinning = 1;
5680
5681         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
5682         BUG_ON(!is_data && refs_to_drop != 1);
5683
5684         if (is_data)
5685                 skinny_metadata = 0;
5686
5687         ret = lookup_extent_backref(trans, extent_root, path, &iref,
5688                                     bytenr, num_bytes, parent,
5689                                     root_objectid, owner_objectid,
5690                                     owner_offset);
5691         if (ret == 0) {
5692                 extent_slot = path->slots[0];
5693                 while (extent_slot >= 0) {
5694                         btrfs_item_key_to_cpu(path->nodes[0], &key,
5695                                               extent_slot);
5696                         if (key.objectid != bytenr)
5697                                 break;
5698                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
5699                             key.offset == num_bytes) {
5700                                 found_extent = 1;
5701                                 break;
5702                         }
5703                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
5704                             key.offset == owner_objectid) {
5705                                 found_extent = 1;
5706                                 break;
5707                         }
5708                         if (path->slots[0] - extent_slot > 5)
5709                                 break;
5710                         extent_slot--;
5711                 }
5712 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5713                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
5714                 if (found_extent && item_size < sizeof(*ei))
5715                         found_extent = 0;
5716 #endif
5717                 if (!found_extent) {
5718                         BUG_ON(iref);
5719                         ret = remove_extent_backref(trans, extent_root, path,
5720                                                     NULL, refs_to_drop,
5721                                                     is_data);
5722                         if (ret) {
5723                                 btrfs_abort_transaction(trans, extent_root, ret);
5724                                 goto out;
5725                         }
5726                         btrfs_release_path(path);
5727                         path->leave_spinning = 1;
5728
5729                         key.objectid = bytenr;
5730                         key.type = BTRFS_EXTENT_ITEM_KEY;
5731                         key.offset = num_bytes;
5732
5733                         if (!is_data && skinny_metadata) {
5734                                 key.type = BTRFS_METADATA_ITEM_KEY;
5735                                 key.offset = owner_objectid;
5736                         }
5737
5738                         ret = btrfs_search_slot(trans, extent_root,
5739                                                 &key, path, -1, 1);
5740                         if (ret > 0 && skinny_metadata && path->slots[0]) {
5741                                 /*
5742                                  * Couldn't find our skinny metadata item,
5743                                  * see if we have ye olde extent item.
5744                                  */
5745                                 path->slots[0]--;
5746                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
5747                                                       path->slots[0]);
5748                                 if (key.objectid == bytenr &&
5749                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
5750                                     key.offset == num_bytes)
5751                                         ret = 0;
5752                         }
5753
5754                         if (ret > 0 && skinny_metadata) {
5755                                 skinny_metadata = false;
5756                                 key.type = BTRFS_EXTENT_ITEM_KEY;
5757                                 key.offset = num_bytes;
5758                                 btrfs_release_path(path);
5759                                 ret = btrfs_search_slot(trans, extent_root,
5760                                                         &key, path, -1, 1);
5761                         }
5762
5763                         if (ret) {
5764                                 btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5765                                         ret, bytenr);
5766                                 if (ret > 0)
5767                                         btrfs_print_leaf(extent_root,
5768                                                          path->nodes[0]);
5769                         }
5770                         if (ret < 0) {
5771                                 btrfs_abort_transaction(trans, extent_root, ret);
5772                                 goto out;
5773                         }
5774                         extent_slot = path->slots[0];
5775                 }
5776         } else if (WARN_ON(ret == -ENOENT)) {
5777                 btrfs_print_leaf(extent_root, path->nodes[0]);
5778                 btrfs_err(info,
5779                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
5780                         bytenr, parent, root_objectid, owner_objectid,
5781                         owner_offset);
5782         } else {
5783                 btrfs_abort_transaction(trans, extent_root, ret);
5784                 goto out;
5785         }
5786
5787         leaf = path->nodes[0];
5788         item_size = btrfs_item_size_nr(leaf, extent_slot);
5789 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
5790         if (item_size < sizeof(*ei)) {
5791                 BUG_ON(found_extent || extent_slot != path->slots[0]);
5792                 ret = convert_extent_item_v0(trans, extent_root, path,
5793                                              owner_objectid, 0);
5794                 if (ret < 0) {
5795                         btrfs_abort_transaction(trans, extent_root, ret);
5796                         goto out;
5797                 }
5798
5799                 btrfs_release_path(path);
5800                 path->leave_spinning = 1;
5801
5802                 key.objectid = bytenr;
5803                 key.type = BTRFS_EXTENT_ITEM_KEY;
5804                 key.offset = num_bytes;
5805
5806                 ret = btrfs_search_slot(trans, extent_root, &key, path,
5807                                         -1, 1);
5808                 if (ret) {
5809                         btrfs_err(info, "umm, got %d back from search, was looking for %llu",
5810                                 ret, bytenr);
5811                         btrfs_print_leaf(extent_root, path->nodes[0]);
5812                 }
5813                 if (ret < 0) {
5814                         btrfs_abort_transaction(trans, extent_root, ret);
5815                         goto out;
5816                 }
5817
5818                 extent_slot = path->slots[0];
5819                 leaf = path->nodes[0];
5820                 item_size = btrfs_item_size_nr(leaf, extent_slot);
5821         }
5822 #endif
5823         BUG_ON(item_size < sizeof(*ei));
5824         ei = btrfs_item_ptr(leaf, extent_slot,
5825                             struct btrfs_extent_item);
5826         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
5827             key.type == BTRFS_EXTENT_ITEM_KEY) {
5828                 struct btrfs_tree_block_info *bi;
5829                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
5830                 bi = (struct btrfs_tree_block_info *)(ei + 1);
5831                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
5832         }
5833
5834         refs = btrfs_extent_refs(leaf, ei);
5835         if (refs < refs_to_drop) {
5836                 btrfs_err(info, "trying to drop %d refs but we only have %Lu "
5837                           "for bytenr %Lu\n", refs_to_drop, refs, bytenr);
5838                 ret = -EINVAL;
5839                 btrfs_abort_transaction(trans, extent_root, ret);
5840                 goto out;
5841         }
5842         refs -= refs_to_drop;
5843
5844         if (refs > 0) {
5845                 if (extent_op)
5846                         __run_delayed_extent_op(extent_op, leaf, ei);
5847                 /*
5848                  * In the case of inline back ref, reference count will
5849                  * be updated by remove_extent_backref
5850                  */
5851                 if (iref) {
5852                         BUG_ON(!found_extent);
5853                 } else {
5854                         btrfs_set_extent_refs(leaf, ei, refs);
5855                         btrfs_mark_buffer_dirty(leaf);
5856                 }
5857                 if (found_extent) {
5858                         ret = remove_extent_backref(trans, extent_root, path,
5859                                                     iref, refs_to_drop,
5860                                                     is_data);
5861                         if (ret) {
5862                                 btrfs_abort_transaction(trans, extent_root, ret);
5863                                 goto out;
5864                         }
5865                 }
5866                 add_pinned_bytes(root->fs_info, -num_bytes, owner_objectid,
5867                                  root_objectid);
5868         } else {
5869                 if (found_extent) {
5870                         BUG_ON(is_data && refs_to_drop !=
5871                                extent_data_ref_count(root, path, iref));
5872                         if (iref) {
5873                                 BUG_ON(path->slots[0] != extent_slot);
5874                         } else {
5875                                 BUG_ON(path->slots[0] != extent_slot + 1);
5876                                 path->slots[0] = extent_slot;
5877                                 num_to_del = 2;
5878                         }
5879                 }
5880
5881                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
5882                                       num_to_del);
5883                 if (ret) {
5884                         btrfs_abort_transaction(trans, extent_root, ret);
5885                         goto out;
5886                 }
5887                 btrfs_release_path(path);
5888
5889                 if (is_data) {
5890                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
5891                         if (ret) {
5892                                 btrfs_abort_transaction(trans, extent_root, ret);
5893                                 goto out;
5894                         }
5895                 }
5896
5897                 ret = update_block_group(root, bytenr, num_bytes, 0);
5898                 if (ret) {
5899                         btrfs_abort_transaction(trans, extent_root, ret);
5900                         goto out;
5901                 }
5902         }
5903 out:
5904         btrfs_free_path(path);
5905         return ret;
5906 }
5907
5908 /*
5909  * when we free an block, it is possible (and likely) that we free the last
5910  * delayed ref for that extent as well.  This searches the delayed ref tree for
5911  * a given extent, and if there are no other delayed refs to be processed, it
5912  * removes it from the tree.
5913  */
5914 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
5915                                       struct btrfs_root *root, u64 bytenr)
5916 {
5917         struct btrfs_delayed_ref_head *head;
5918         struct btrfs_delayed_ref_root *delayed_refs;
5919         struct btrfs_delayed_ref_node *ref;
5920         struct rb_node *node;
5921         int ret = 0;
5922
5923         delayed_refs = &trans->transaction->delayed_refs;
5924         spin_lock(&delayed_refs->lock);
5925         head = btrfs_find_delayed_ref_head(trans, bytenr);
5926         if (!head)
5927                 goto out;
5928
5929         node = rb_prev(&head->node.rb_node);
5930         if (!node)
5931                 goto out;
5932
5933         ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
5934
5935         /* there are still entries for this ref, we can't drop it */
5936         if (ref->bytenr == bytenr)
5937                 goto out;
5938
5939         if (head->extent_op) {
5940                 if (!head->must_insert_reserved)
5941                         goto out;
5942                 btrfs_free_delayed_extent_op(head->extent_op);
5943                 head->extent_op = NULL;
5944         }
5945
5946         /*
5947          * waiting for the lock here would deadlock.  If someone else has it
5948          * locked they are already in the process of dropping it anyway
5949          */
5950         if (!mutex_trylock(&head->mutex))
5951                 goto out;
5952
5953         /*
5954          * at this point we have a head with no other entries.  Go
5955          * ahead and process it.
5956          */
5957         head->node.in_tree = 0;
5958         rb_erase(&head->node.rb_node, &delayed_refs->root);
5959
5960         delayed_refs->num_entries--;
5961
5962         /*
5963          * we don't take a ref on the node because we're removing it from the
5964          * tree, so we just steal the ref the tree was holding.
5965          */
5966         delayed_refs->num_heads--;
5967         if (list_empty(&head->cluster))
5968                 delayed_refs->num_heads_ready--;
5969
5970         list_del_init(&head->cluster);
5971         spin_unlock(&delayed_refs->lock);
5972
5973         BUG_ON(head->extent_op);
5974         if (head->must_insert_reserved)
5975                 ret = 1;
5976
5977         mutex_unlock(&head->mutex);
5978         btrfs_put_delayed_ref(&head->node);
5979         return ret;
5980 out:
5981         spin_unlock(&delayed_refs->lock);
5982         return 0;
5983 }
5984
5985 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
5986                            struct btrfs_root *root,
5987                            struct extent_buffer *buf,
5988                            u64 parent, int last_ref)
5989 {
5990         struct btrfs_block_group_cache *cache = NULL;
5991         int pin = 1;
5992         int ret;
5993
5994         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
5995                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
5996                                         buf->start, buf->len,
5997                                         parent, root->root_key.objectid,
5998                                         btrfs_header_level(buf),
5999                                         BTRFS_DROP_DELAYED_REF, NULL, 0);
6000                 BUG_ON(ret); /* -ENOMEM */
6001         }
6002
6003         if (!last_ref)
6004                 return;
6005
6006         cache = btrfs_lookup_block_group(root->fs_info, buf->start);
6007
6008         if (btrfs_header_generation(buf) == trans->transid) {
6009                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
6010                         ret = check_ref_cleanup(trans, root, buf->start);
6011                         if (!ret)
6012                                 goto out;
6013                 }
6014
6015                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
6016                         pin_down_extent(root, cache, buf->start, buf->len, 1);
6017                         goto out;
6018                 }
6019
6020                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
6021
6022                 btrfs_add_free_space(cache, buf->start, buf->len);
6023                 btrfs_update_reserved_bytes(cache, buf->len, RESERVE_FREE);
6024                 trace_btrfs_reserved_extent_free(root, buf->start, buf->len);
6025                 pin = 0;
6026         }
6027 out:
6028         if (pin)
6029                 add_pinned_bytes(root->fs_info, buf->len,
6030                                  btrfs_header_level(buf),
6031                                  root->root_key.objectid);
6032
6033         /*
6034          * Deleting the buffer, clear the corrupt flag since it doesn't matter
6035          * anymore.
6036          */
6037         clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
6038         btrfs_put_block_group(cache);
6039 }
6040
6041 /* Can return -ENOMEM */
6042 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6043                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
6044                       u64 owner, u64 offset, int for_cow)
6045 {
6046         int ret;
6047         struct btrfs_fs_info *fs_info = root->fs_info;
6048
6049         add_pinned_bytes(root->fs_info, num_bytes, owner, root_objectid);
6050
6051         /*
6052          * tree log blocks never actually go into the extent allocation
6053          * tree, just update pinning info and exit early.
6054          */
6055         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
6056                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
6057                 /* unlocks the pinned mutex */
6058                 btrfs_pin_extent(root, bytenr, num_bytes, 1);
6059                 ret = 0;
6060         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
6061                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
6062                                         num_bytes,
6063                                         parent, root_objectid, (int)owner,
6064                                         BTRFS_DROP_DELAYED_REF, NULL, for_cow);
6065         } else {
6066                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
6067                                                 num_bytes,
6068                                                 parent, root_objectid, owner,
6069                                                 offset, BTRFS_DROP_DELAYED_REF,
6070                                                 NULL, for_cow);
6071         }
6072         return ret;
6073 }
6074
6075 static u64 stripe_align(struct btrfs_root *root,
6076                         struct btrfs_block_group_cache *cache,
6077                         u64 val, u64 num_bytes)
6078 {
6079         u64 ret = ALIGN(val, root->stripesize);
6080         return ret;
6081 }
6082
6083 /*
6084  * when we wait for progress in the block group caching, its because
6085  * our allocation attempt failed at least once.  So, we must sleep
6086  * and let some progress happen before we try again.
6087  *
6088  * This function will sleep at least once waiting for new free space to
6089  * show up, and then it will check the block group free space numbers
6090  * for our min num_bytes.  Another option is to have it go ahead
6091  * and look in the rbtree for a free extent of a given size, but this
6092  * is a good start.
6093  *
6094  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
6095  * any of the information in this block group.
6096  */
6097 static noinline void
6098 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
6099                                 u64 num_bytes)
6100 {
6101         struct btrfs_caching_control *caching_ctl;
6102
6103         caching_ctl = get_caching_control(cache);
6104         if (!caching_ctl)
6105                 return;
6106
6107         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
6108                    (cache->free_space_ctl->free_space >= num_bytes));
6109
6110         put_caching_control(caching_ctl);
6111 }
6112
6113 static noinline int
6114 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
6115 {
6116         struct btrfs_caching_control *caching_ctl;
6117         int ret = 0;
6118
6119         caching_ctl = get_caching_control(cache);
6120         if (!caching_ctl)
6121                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
6122
6123         wait_event(caching_ctl->wait, block_group_cache_done(cache));
6124         if (cache->cached == BTRFS_CACHE_ERROR)
6125                 ret = -EIO;
6126         put_caching_control(caching_ctl);
6127         return ret;
6128 }
6129
6130 int __get_raid_index(u64 flags)
6131 {
6132         if (flags & BTRFS_BLOCK_GROUP_RAID10)
6133                 return BTRFS_RAID_RAID10;
6134         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
6135                 return BTRFS_RAID_RAID1;
6136         else if (flags & BTRFS_BLOCK_GROUP_DUP)
6137                 return BTRFS_RAID_DUP;
6138         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
6139                 return BTRFS_RAID_RAID0;
6140         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
6141                 return BTRFS_RAID_RAID5;
6142         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
6143                 return BTRFS_RAID_RAID6;
6144
6145         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
6146 }
6147
6148 static int get_block_group_index(struct btrfs_block_group_cache *cache)
6149 {
6150         return __get_raid_index(cache->flags);
6151 }
6152
6153 enum btrfs_loop_type {
6154         LOOP_CACHING_NOWAIT = 0,
6155         LOOP_CACHING_WAIT = 1,
6156         LOOP_ALLOC_CHUNK = 2,
6157         LOOP_NO_EMPTY_SIZE = 3,
6158 };
6159
6160 /*
6161  * walks the btree of allocated extents and find a hole of a given size.
6162  * The key ins is changed to record the hole:
6163  * ins->objectid == start position
6164  * ins->flags = BTRFS_EXTENT_ITEM_KEY
6165  * ins->offset == the size of the hole.
6166  * Any available blocks before search_start are skipped.
6167  *
6168  * If there is no suitable free space, we will record the max size of
6169  * the free space extent currently.
6170  */
6171 static noinline int find_free_extent(struct btrfs_root *orig_root,
6172                                      u64 num_bytes, u64 empty_size,
6173                                      u64 hint_byte, struct btrfs_key *ins,
6174                                      u64 flags)
6175 {
6176         int ret = 0;
6177         struct btrfs_root *root = orig_root->fs_info->extent_root;
6178         struct btrfs_free_cluster *last_ptr = NULL;
6179         struct btrfs_block_group_cache *block_group = NULL;
6180         struct btrfs_block_group_cache *used_block_group;
6181         u64 search_start = 0;
6182         u64 max_extent_size = 0;
6183         int empty_cluster = 2 * 1024 * 1024;
6184         struct btrfs_space_info *space_info;
6185         int loop = 0;
6186         int index = __get_raid_index(flags);
6187         int alloc_type = (flags & BTRFS_BLOCK_GROUP_DATA) ?
6188                 RESERVE_ALLOC_NO_ACCOUNT : RESERVE_ALLOC;
6189         bool found_uncached_bg = false;
6190         bool failed_cluster_refill = false;
6191         bool failed_alloc = false;
6192         bool use_cluster = true;
6193         bool have_caching_bg = false;
6194
6195         WARN_ON(num_bytes < root->sectorsize);
6196         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
6197         ins->objectid = 0;
6198         ins->offset = 0;
6199
6200         trace_find_free_extent(orig_root, num_bytes, empty_size, flags);
6201
6202         space_info = __find_space_info(root->fs_info, flags);
6203         if (!space_info) {
6204                 btrfs_err(root->fs_info, "No space info for %llu", flags);
6205                 return -ENOSPC;
6206         }
6207
6208         /*
6209          * If the space info is for both data and metadata it means we have a
6210          * small filesystem and we can't use the clustering stuff.
6211          */
6212         if (btrfs_mixed_space_info(space_info))
6213                 use_cluster = false;
6214
6215         if (flags & BTRFS_BLOCK_GROUP_METADATA && use_cluster) {
6216                 last_ptr = &root->fs_info->meta_alloc_cluster;
6217                 if (!btrfs_test_opt(root, SSD))
6218                         empty_cluster = 64 * 1024;
6219         }
6220
6221         if ((flags & BTRFS_BLOCK_GROUP_DATA) && use_cluster &&
6222             btrfs_test_opt(root, SSD)) {
6223                 last_ptr = &root->fs_info->data_alloc_cluster;
6224         }
6225
6226         if (last_ptr) {
6227                 spin_lock(&last_ptr->lock);
6228                 if (last_ptr->block_group)
6229                         hint_byte = last_ptr->window_start;
6230                 spin_unlock(&last_ptr->lock);
6231         }
6232
6233         search_start = max(search_start, first_logical_byte(root, 0));
6234         search_start = max(search_start, hint_byte);
6235
6236         if (!last_ptr)
6237                 empty_cluster = 0;
6238
6239         if (search_start == hint_byte) {
6240                 block_group = btrfs_lookup_block_group(root->fs_info,
6241                                                        search_start);
6242                 used_block_group = block_group;
6243                 /*
6244                  * we don't want to use the block group if it doesn't match our
6245                  * allocation bits, or if its not cached.
6246                  *
6247                  * However if we are re-searching with an ideal block group
6248                  * picked out then we don't care that the block group is cached.
6249                  */
6250                 if (block_group && block_group_bits(block_group, flags) &&
6251                     block_group->cached != BTRFS_CACHE_NO) {
6252                         down_read(&space_info->groups_sem);
6253                         if (list_empty(&block_group->list) ||
6254                             block_group->ro) {
6255                                 /*
6256                                  * someone is removing this block group,
6257                                  * we can't jump into the have_block_group
6258                                  * target because our list pointers are not
6259                                  * valid
6260                                  */
6261                                 btrfs_put_block_group(block_group);
6262                                 up_read(&space_info->groups_sem);
6263                         } else {
6264                                 index = get_block_group_index(block_group);
6265                                 goto have_block_group;
6266                         }
6267                 } else if (block_group) {
6268                         btrfs_put_block_group(block_group);
6269                 }
6270         }
6271 search:
6272         have_caching_bg = false;
6273         down_read(&space_info->groups_sem);
6274         list_for_each_entry(block_group, &space_info->block_groups[index],
6275                             list) {
6276                 u64 offset;
6277                 int cached;
6278
6279                 used_block_group = block_group;
6280                 btrfs_get_block_group(block_group);
6281                 search_start = block_group->key.objectid;
6282
6283                 /*
6284                  * this can happen if we end up cycling through all the
6285                  * raid types, but we want to make sure we only allocate
6286                  * for the proper type.
6287                  */
6288                 if (!block_group_bits(block_group, flags)) {
6289                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
6290                                 BTRFS_BLOCK_GROUP_RAID1 |
6291                                 BTRFS_BLOCK_GROUP_RAID5 |
6292                                 BTRFS_BLOCK_GROUP_RAID6 |
6293                                 BTRFS_BLOCK_GROUP_RAID10;
6294
6295                         /*
6296                          * if they asked for extra copies and this block group
6297                          * doesn't provide them, bail.  This does allow us to
6298                          * fill raid0 from raid1.
6299                          */
6300                         if ((flags & extra) && !(block_group->flags & extra))
6301                                 goto loop;
6302                 }
6303
6304 have_block_group:
6305                 cached = block_group_cache_done(block_group);
6306                 if (unlikely(!cached)) {
6307                         found_uncached_bg = true;
6308                         ret = cache_block_group(block_group, 0);
6309                         BUG_ON(ret < 0);
6310                         ret = 0;
6311                 }
6312
6313                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
6314                         goto loop;
6315                 if (unlikely(block_group->ro))
6316                         goto loop;
6317
6318                 /*
6319                  * Ok we want to try and use the cluster allocator, so
6320                  * lets look there
6321                  */
6322                 if (last_ptr) {
6323                         unsigned long aligned_cluster;
6324                         /*
6325                          * the refill lock keeps out other
6326                          * people trying to start a new cluster
6327                          */
6328                         spin_lock(&last_ptr->refill_lock);
6329                         used_block_group = last_ptr->block_group;
6330                         if (used_block_group != block_group &&
6331                             (!used_block_group ||
6332                              used_block_group->ro ||
6333                              !block_group_bits(used_block_group, flags))) {
6334                                 used_block_group = block_group;
6335                                 goto refill_cluster;
6336                         }
6337
6338                         if (used_block_group != block_group)
6339                                 btrfs_get_block_group(used_block_group);
6340
6341                         offset = btrfs_alloc_from_cluster(used_block_group,
6342                                                 last_ptr,
6343                                                 num_bytes,
6344                                                 used_block_group->key.objectid,
6345                                                 &max_extent_size);
6346                         if (offset) {
6347                                 /* we have a block, we're done */
6348                                 spin_unlock(&last_ptr->refill_lock);
6349                                 trace_btrfs_reserve_extent_cluster(root,
6350                                         block_group, search_start, num_bytes);
6351                                 goto checks;
6352                         }
6353
6354                         WARN_ON(last_ptr->block_group != used_block_group);
6355                         if (used_block_group != block_group) {
6356                                 btrfs_put_block_group(used_block_group);
6357                                 used_block_group = block_group;
6358                         }
6359 refill_cluster:
6360                         BUG_ON(used_block_group != block_group);
6361                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
6362                          * set up a new clusters, so lets just skip it
6363                          * and let the allocator find whatever block
6364                          * it can find.  If we reach this point, we
6365                          * will have tried the cluster allocator
6366                          * plenty of times and not have found
6367                          * anything, so we are likely way too
6368                          * fragmented for the clustering stuff to find
6369                          * anything.
6370                          *
6371                          * However, if the cluster is taken from the
6372                          * current block group, release the cluster
6373                          * first, so that we stand a better chance of
6374                          * succeeding in the unclustered
6375                          * allocation.  */
6376                         if (loop >= LOOP_NO_EMPTY_SIZE &&
6377                             last_ptr->block_group != block_group) {
6378                                 spin_unlock(&last_ptr->refill_lock);
6379                                 goto unclustered_alloc;
6380                         }
6381
6382                         /*
6383                          * this cluster didn't work out, free it and
6384                          * start over
6385                          */
6386                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6387
6388                         if (loop >= LOOP_NO_EMPTY_SIZE) {
6389                                 spin_unlock(&last_ptr->refill_lock);
6390                                 goto unclustered_alloc;
6391                         }
6392
6393                         aligned_cluster = max_t(unsigned long,
6394                                                 empty_cluster + empty_size,
6395                                               block_group->full_stripe_len);
6396
6397                         /* allocate a cluster in this block group */
6398                         ret = btrfs_find_space_cluster(root, block_group,
6399                                                        last_ptr, search_start,
6400                                                        num_bytes,
6401                                                        aligned_cluster);
6402                         if (ret == 0) {
6403                                 /*
6404                                  * now pull our allocation out of this
6405                                  * cluster
6406                                  */
6407                                 offset = btrfs_alloc_from_cluster(block_group,
6408                                                         last_ptr,
6409                                                         num_bytes,
6410                                                         search_start,
6411                                                         &max_extent_size);
6412                                 if (offset) {
6413                                         /* we found one, proceed */
6414                                         spin_unlock(&last_ptr->refill_lock);
6415                                         trace_btrfs_reserve_extent_cluster(root,
6416                                                 block_group, search_start,
6417                                                 num_bytes);
6418                                         goto checks;
6419                                 }
6420                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
6421                                    && !failed_cluster_refill) {
6422                                 spin_unlock(&last_ptr->refill_lock);
6423
6424                                 failed_cluster_refill = true;
6425                                 wait_block_group_cache_progress(block_group,
6426                                        num_bytes + empty_cluster + empty_size);
6427                                 goto have_block_group;
6428                         }
6429
6430                         /*
6431                          * at this point we either didn't find a cluster
6432                          * or we weren't able to allocate a block from our
6433                          * cluster.  Free the cluster we've been trying
6434                          * to use, and go to the next block group
6435                          */
6436                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
6437                         spin_unlock(&last_ptr->refill_lock);
6438                         goto loop;
6439                 }
6440
6441 unclustered_alloc:
6442                 spin_lock(&block_group->free_space_ctl->tree_lock);
6443                 if (cached &&
6444                     block_group->free_space_ctl->free_space <
6445                     num_bytes + empty_cluster + empty_size) {
6446                         if (block_group->free_space_ctl->free_space >
6447                             max_extent_size)
6448                                 max_extent_size =
6449                                         block_group->free_space_ctl->free_space;
6450                         spin_unlock(&block_group->free_space_ctl->tree_lock);
6451                         goto loop;
6452                 }
6453                 spin_unlock(&block_group->free_space_ctl->tree_lock);
6454
6455                 offset = btrfs_find_space_for_alloc(block_group, search_start,
6456                                                     num_bytes, empty_size,
6457                                                     &max_extent_size);
6458                 /*
6459                  * If we didn't find a chunk, and we haven't failed on this
6460                  * block group before, and this block group is in the middle of
6461                  * caching and we are ok with waiting, then go ahead and wait
6462                  * for progress to be made, and set failed_alloc to true.
6463                  *
6464                  * If failed_alloc is true then we've already waited on this
6465                  * block group once and should move on to the next block group.
6466                  */
6467                 if (!offset && !failed_alloc && !cached &&
6468                     loop > LOOP_CACHING_NOWAIT) {
6469                         wait_block_group_cache_progress(block_group,
6470                                                 num_bytes + empty_size);
6471                         failed_alloc = true;
6472                         goto have_block_group;
6473                 } else if (!offset) {
6474                         if (!cached)
6475                                 have_caching_bg = true;
6476                         goto loop;
6477                 }
6478 checks:
6479                 search_start = stripe_align(root, used_block_group,
6480                                             offset, num_bytes);
6481
6482                 /* move on to the next group */
6483                 if (search_start + num_bytes >
6484                     used_block_group->key.objectid + used_block_group->key.offset) {
6485                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6486                         goto loop;
6487                 }
6488
6489                 if (offset < search_start)
6490                         btrfs_add_free_space(used_block_group, offset,
6491                                              search_start - offset);
6492                 BUG_ON(offset > search_start);
6493
6494                 ret = btrfs_update_reserved_bytes(used_block_group, num_bytes,
6495                                                   alloc_type);
6496                 if (ret == -EAGAIN) {
6497                         btrfs_add_free_space(used_block_group, offset, num_bytes);
6498                         goto loop;
6499                 }
6500
6501                 /* we are all good, lets return */
6502                 ins->objectid = search_start;
6503                 ins->offset = num_bytes;
6504
6505                 trace_btrfs_reserve_extent(orig_root, block_group,
6506                                            search_start, num_bytes);
6507                 if (used_block_group != block_group)
6508                         btrfs_put_block_group(used_block_group);
6509                 btrfs_put_block_group(block_group);
6510                 break;
6511 loop:
6512                 failed_cluster_refill = false;
6513                 failed_alloc = false;
6514                 BUG_ON(index != get_block_group_index(block_group));
6515                 if (used_block_group != block_group)
6516                         btrfs_put_block_group(used_block_group);
6517                 btrfs_put_block_group(block_group);
6518         }
6519         up_read(&space_info->groups_sem);
6520
6521         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
6522                 goto search;
6523
6524         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
6525                 goto search;
6526
6527         /*
6528          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
6529          *                      caching kthreads as we move along
6530          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
6531          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
6532          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
6533          *                      again
6534          */
6535         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
6536                 index = 0;
6537                 loop++;
6538                 if (loop == LOOP_ALLOC_CHUNK) {
6539                         struct btrfs_trans_handle *trans;
6540
6541                         trans = btrfs_join_transaction(root);
6542                         if (IS_ERR(trans)) {
6543                                 ret = PTR_ERR(trans);
6544                                 goto out;
6545                         }
6546
6547                         ret = do_chunk_alloc(trans, root, flags,
6548                                              CHUNK_ALLOC_FORCE);
6549                         /*
6550                          * Do not bail out on ENOSPC since we
6551                          * can do more things.
6552                          */
6553                         if (ret < 0 && ret != -ENOSPC)
6554                                 btrfs_abort_transaction(trans,
6555                                                         root, ret);
6556                         else
6557                                 ret = 0;
6558                         btrfs_end_transaction(trans, root);
6559                         if (ret)
6560                                 goto out;
6561                 }
6562
6563                 if (loop == LOOP_NO_EMPTY_SIZE) {
6564                         empty_size = 0;
6565                         empty_cluster = 0;
6566                 }
6567
6568                 goto search;
6569         } else if (!ins->objectid) {
6570                 ret = -ENOSPC;
6571         } else if (ins->objectid) {
6572                 ret = 0;
6573         }
6574 out:
6575         if (ret == -ENOSPC)
6576                 ins->offset = max_extent_size;
6577         return ret;
6578 }
6579
6580 static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
6581                             int dump_block_groups)
6582 {
6583         struct btrfs_block_group_cache *cache;
6584         int index = 0;
6585
6586         spin_lock(&info->lock);
6587         printk(KERN_INFO "space_info %llu has %llu free, is %sfull\n",
6588                info->flags,
6589                info->total_bytes - info->bytes_used - info->bytes_pinned -
6590                info->bytes_reserved - info->bytes_readonly,
6591                (info->full) ? "" : "not ");
6592         printk(KERN_INFO "space_info total=%llu, used=%llu, pinned=%llu, "
6593                "reserved=%llu, may_use=%llu, readonly=%llu\n",
6594                info->total_bytes, info->bytes_used, info->bytes_pinned,
6595                info->bytes_reserved, info->bytes_may_use,
6596                info->bytes_readonly);
6597         spin_unlock(&info->lock);
6598
6599         if (!dump_block_groups)
6600                 return;
6601
6602         down_read(&info->groups_sem);
6603 again:
6604         list_for_each_entry(cache, &info->block_groups[index], list) {
6605                 spin_lock(&cache->lock);
6606                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s\n",
6607                        cache->key.objectid, cache->key.offset,
6608                        btrfs_block_group_used(&cache->item), cache->pinned,
6609                        cache->reserved, cache->ro ? "[readonly]" : "");
6610                 btrfs_dump_free_space(cache, bytes);
6611                 spin_unlock(&cache->lock);
6612         }
6613         if (++index < BTRFS_NR_RAID_TYPES)
6614                 goto again;
6615         up_read(&info->groups_sem);
6616 }
6617
6618 int btrfs_reserve_extent(struct btrfs_root *root,
6619                          u64 num_bytes, u64 min_alloc_size,
6620                          u64 empty_size, u64 hint_byte,
6621                          struct btrfs_key *ins, int is_data)
6622 {
6623         bool final_tried = false;
6624         u64 flags;
6625         int ret;
6626
6627         flags = btrfs_get_alloc_profile(root, is_data);
6628 again:
6629         WARN_ON(num_bytes < root->sectorsize);
6630         ret = find_free_extent(root, num_bytes, empty_size, hint_byte, ins,
6631                                flags);
6632
6633         if (ret == -ENOSPC) {
6634                 if (!final_tried && ins->offset) {
6635                         num_bytes = min(num_bytes >> 1, ins->offset);
6636                         num_bytes = round_down(num_bytes, root->sectorsize);
6637                         num_bytes = max(num_bytes, min_alloc_size);
6638                         if (num_bytes == min_alloc_size)
6639                                 final_tried = true;
6640                         goto again;
6641                 } else if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6642                         struct btrfs_space_info *sinfo;
6643
6644                         sinfo = __find_space_info(root->fs_info, flags);
6645                         btrfs_err(root->fs_info, "allocation failed flags %llu, wanted %llu",
6646                                 flags, num_bytes);
6647                         if (sinfo)
6648                                 dump_space_info(sinfo, num_bytes, 1);
6649                 }
6650         }
6651
6652         return ret;
6653 }
6654
6655 static int __btrfs_free_reserved_extent(struct btrfs_root *root,
6656                                         u64 start, u64 len, int pin)
6657 {
6658         struct btrfs_block_group_cache *cache;
6659         int ret = 0;
6660
6661         cache = btrfs_lookup_block_group(root->fs_info, start);
6662         if (!cache) {
6663                 btrfs_err(root->fs_info, "Unable to find block group for %llu",
6664                         start);
6665                 return -ENOSPC;
6666         }
6667
6668         if (btrfs_test_opt(root, DISCARD))
6669                 ret = btrfs_discard_extent(root, start, len, NULL);
6670
6671         if (pin)
6672                 pin_down_extent(root, cache, start, len, 1);
6673         else {
6674                 btrfs_add_free_space(cache, start, len);
6675                 btrfs_update_reserved_bytes(cache, len, RESERVE_FREE);
6676         }
6677         btrfs_put_block_group(cache);
6678
6679         trace_btrfs_reserved_extent_free(root, start, len);
6680
6681         return ret;
6682 }
6683
6684 int btrfs_free_reserved_extent(struct btrfs_root *root,
6685                                         u64 start, u64 len)
6686 {
6687         return __btrfs_free_reserved_extent(root, start, len, 0);
6688 }
6689
6690 int btrfs_free_and_pin_reserved_extent(struct btrfs_root *root,
6691                                        u64 start, u64 len)
6692 {
6693         return __btrfs_free_reserved_extent(root, start, len, 1);
6694 }
6695
6696 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6697                                       struct btrfs_root *root,
6698                                       u64 parent, u64 root_objectid,
6699                                       u64 flags, u64 owner, u64 offset,
6700                                       struct btrfs_key *ins, int ref_mod)
6701 {
6702         int ret;
6703         struct btrfs_fs_info *fs_info = root->fs_info;
6704         struct btrfs_extent_item *extent_item;
6705         struct btrfs_extent_inline_ref *iref;
6706         struct btrfs_path *path;
6707         struct extent_buffer *leaf;
6708         int type;
6709         u32 size;
6710
6711         if (parent > 0)
6712                 type = BTRFS_SHARED_DATA_REF_KEY;
6713         else
6714                 type = BTRFS_EXTENT_DATA_REF_KEY;
6715
6716         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
6717
6718         path = btrfs_alloc_path();
6719         if (!path)
6720                 return -ENOMEM;
6721
6722         path->leave_spinning = 1;
6723         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6724                                       ins, size);
6725         if (ret) {
6726                 btrfs_free_path(path);
6727                 return ret;
6728         }
6729
6730         leaf = path->nodes[0];
6731         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6732                                      struct btrfs_extent_item);
6733         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
6734         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6735         btrfs_set_extent_flags(leaf, extent_item,
6736                                flags | BTRFS_EXTENT_FLAG_DATA);
6737
6738         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6739         btrfs_set_extent_inline_ref_type(leaf, iref, type);
6740         if (parent > 0) {
6741                 struct btrfs_shared_data_ref *ref;
6742                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
6743                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6744                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
6745         } else {
6746                 struct btrfs_extent_data_ref *ref;
6747                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
6748                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
6749                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
6750                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
6751                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
6752         }
6753
6754         btrfs_mark_buffer_dirty(path->nodes[0]);
6755         btrfs_free_path(path);
6756
6757         ret = update_block_group(root, ins->objectid, ins->offset, 1);
6758         if (ret) { /* -ENOENT, logic error */
6759                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6760                         ins->objectid, ins->offset);
6761                 BUG();
6762         }
6763         trace_btrfs_reserved_extent_alloc(root, ins->objectid, ins->offset);
6764         return ret;
6765 }
6766
6767 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
6768                                      struct btrfs_root *root,
6769                                      u64 parent, u64 root_objectid,
6770                                      u64 flags, struct btrfs_disk_key *key,
6771                                      int level, struct btrfs_key *ins)
6772 {
6773         int ret;
6774         struct btrfs_fs_info *fs_info = root->fs_info;
6775         struct btrfs_extent_item *extent_item;
6776         struct btrfs_tree_block_info *block_info;
6777         struct btrfs_extent_inline_ref *iref;
6778         struct btrfs_path *path;
6779         struct extent_buffer *leaf;
6780         u32 size = sizeof(*extent_item) + sizeof(*iref);
6781         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
6782                                                  SKINNY_METADATA);
6783
6784         if (!skinny_metadata)
6785                 size += sizeof(*block_info);
6786
6787         path = btrfs_alloc_path();
6788         if (!path) {
6789                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
6790                                                    root->leafsize);
6791                 return -ENOMEM;
6792         }
6793
6794         path->leave_spinning = 1;
6795         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
6796                                       ins, size);
6797         if (ret) {
6798                 btrfs_free_and_pin_reserved_extent(root, ins->objectid,
6799                                                    root->leafsize);
6800                 btrfs_free_path(path);
6801                 return ret;
6802         }
6803
6804         leaf = path->nodes[0];
6805         extent_item = btrfs_item_ptr(leaf, path->slots[0],
6806                                      struct btrfs_extent_item);
6807         btrfs_set_extent_refs(leaf, extent_item, 1);
6808         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
6809         btrfs_set_extent_flags(leaf, extent_item,
6810                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
6811
6812         if (skinny_metadata) {
6813                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
6814         } else {
6815                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
6816                 btrfs_set_tree_block_key(leaf, block_info, key);
6817                 btrfs_set_tree_block_level(leaf, block_info, level);
6818                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
6819         }
6820
6821         if (parent > 0) {
6822                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
6823                 btrfs_set_extent_inline_ref_type(leaf, iref,
6824                                                  BTRFS_SHARED_BLOCK_REF_KEY);
6825                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
6826         } else {
6827                 btrfs_set_extent_inline_ref_type(leaf, iref,
6828                                                  BTRFS_TREE_BLOCK_REF_KEY);
6829                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
6830         }
6831
6832         btrfs_mark_buffer_dirty(leaf);
6833         btrfs_free_path(path);
6834
6835         ret = update_block_group(root, ins->objectid, root->leafsize, 1);
6836         if (ret) { /* -ENOENT, logic error */
6837                 btrfs_err(fs_info, "update block group failed for %llu %llu",
6838                         ins->objectid, ins->offset);
6839                 BUG();
6840         }
6841
6842         trace_btrfs_reserved_extent_alloc(root, ins->objectid, root->leafsize);
6843         return ret;
6844 }
6845
6846 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
6847                                      struct btrfs_root *root,
6848                                      u64 root_objectid, u64 owner,
6849                                      u64 offset, struct btrfs_key *ins)
6850 {
6851         int ret;
6852
6853         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
6854
6855         ret = btrfs_add_delayed_data_ref(root->fs_info, trans, ins->objectid,
6856                                          ins->offset, 0,
6857                                          root_objectid, owner, offset,
6858                                          BTRFS_ADD_DELAYED_EXTENT, NULL, 0);
6859         return ret;
6860 }
6861
6862 /*
6863  * this is used by the tree logging recovery code.  It records that
6864  * an extent has been allocated and makes sure to clear the free
6865  * space cache bits as well
6866  */
6867 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
6868                                    struct btrfs_root *root,
6869                                    u64 root_objectid, u64 owner, u64 offset,
6870                                    struct btrfs_key *ins)
6871 {
6872         int ret;
6873         struct btrfs_block_group_cache *block_group;
6874
6875         /*
6876          * Mixed block groups will exclude before processing the log so we only
6877          * need to do the exlude dance if this fs isn't mixed.
6878          */
6879         if (!btrfs_fs_incompat(root->fs_info, MIXED_GROUPS)) {
6880                 ret = __exclude_logged_extent(root, ins->objectid, ins->offset);
6881                 if (ret)
6882                         return ret;
6883         }
6884
6885         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
6886         if (!block_group)
6887                 return -EINVAL;
6888
6889         ret = btrfs_update_reserved_bytes(block_group, ins->offset,
6890                                           RESERVE_ALLOC_NO_ACCOUNT);
6891         BUG_ON(ret); /* logic error */
6892         ret = alloc_reserved_file_extent(trans, root, 0, root_objectid,
6893                                          0, owner, offset, ins, 1);
6894         btrfs_put_block_group(block_group);
6895         return ret;
6896 }
6897
6898 static struct extent_buffer *
6899 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
6900                       u64 bytenr, u32 blocksize, int level)
6901 {
6902         struct extent_buffer *buf;
6903
6904         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
6905         if (!buf)
6906                 return ERR_PTR(-ENOMEM);
6907         btrfs_set_header_generation(buf, trans->transid);
6908         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
6909         btrfs_tree_lock(buf);
6910         clean_tree_block(trans, root, buf);
6911         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
6912
6913         btrfs_set_lock_blocking(buf);
6914         btrfs_set_buffer_uptodate(buf);
6915
6916         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
6917                 /*
6918                  * we allow two log transactions at a time, use different
6919                  * EXENT bit to differentiate dirty pages.
6920                  */
6921                 if (root->log_transid % 2 == 0)
6922                         set_extent_dirty(&root->dirty_log_pages, buf->start,
6923                                         buf->start + buf->len - 1, GFP_NOFS);
6924                 else
6925                         set_extent_new(&root->dirty_log_pages, buf->start,
6926                                         buf->start + buf->len - 1, GFP_NOFS);
6927         } else {
6928                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
6929                          buf->start + buf->len - 1, GFP_NOFS);
6930         }
6931         trans->blocks_used++;
6932         /* this returns a buffer locked for blocking */
6933         return buf;
6934 }
6935
6936 static struct btrfs_block_rsv *
6937 use_block_rsv(struct btrfs_trans_handle *trans,
6938               struct btrfs_root *root, u32 blocksize)
6939 {
6940         struct btrfs_block_rsv *block_rsv;
6941         struct btrfs_block_rsv *global_rsv = &root->fs_info->global_block_rsv;
6942         int ret;
6943         bool global_updated = false;
6944
6945         block_rsv = get_block_rsv(trans, root);
6946
6947         if (unlikely(block_rsv->size == 0))
6948                 goto try_reserve;
6949 again:
6950         ret = block_rsv_use_bytes(block_rsv, blocksize);
6951         if (!ret)
6952                 return block_rsv;
6953
6954         if (block_rsv->failfast)
6955                 return ERR_PTR(ret);
6956
6957         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
6958                 global_updated = true;
6959                 update_global_block_rsv(root->fs_info);
6960                 goto again;
6961         }
6962
6963         if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
6964                 static DEFINE_RATELIMIT_STATE(_rs,
6965                                 DEFAULT_RATELIMIT_INTERVAL * 10,
6966                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
6967                 if (__ratelimit(&_rs))
6968                         WARN(1, KERN_DEBUG
6969                                 "btrfs: block rsv returned %d\n", ret);
6970         }
6971 try_reserve:
6972         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
6973                                      BTRFS_RESERVE_NO_FLUSH);
6974         if (!ret)
6975                 return block_rsv;
6976         /*
6977          * If we couldn't reserve metadata bytes try and use some from
6978          * the global reserve if its space type is the same as the global
6979          * reservation.
6980          */
6981         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
6982             block_rsv->space_info == global_rsv->space_info) {
6983                 ret = block_rsv_use_bytes(global_rsv, blocksize);
6984                 if (!ret)
6985                         return global_rsv;
6986         }
6987         return ERR_PTR(ret);
6988 }
6989
6990 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
6991                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
6992 {
6993         block_rsv_add_bytes(block_rsv, blocksize, 0);
6994         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
6995 }
6996
6997 /*
6998  * finds a free extent and does all the dirty work required for allocation
6999  * returns the key for the extent through ins, and a tree buffer for
7000  * the first block of the extent through buf.
7001  *
7002  * returns the tree buffer or NULL.
7003  */
7004 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
7005                                         struct btrfs_root *root, u32 blocksize,
7006                                         u64 parent, u64 root_objectid,
7007                                         struct btrfs_disk_key *key, int level,
7008                                         u64 hint, u64 empty_size)
7009 {
7010         struct btrfs_key ins;
7011         struct btrfs_block_rsv *block_rsv;
7012         struct extent_buffer *buf;
7013         u64 flags = 0;
7014         int ret;
7015         bool skinny_metadata = btrfs_fs_incompat(root->fs_info,
7016                                                  SKINNY_METADATA);
7017
7018         block_rsv = use_block_rsv(trans, root, blocksize);
7019         if (IS_ERR(block_rsv))
7020                 return ERR_CAST(block_rsv);
7021
7022         ret = btrfs_reserve_extent(root, blocksize, blocksize,
7023                                    empty_size, hint, &ins, 0);
7024         if (ret) {
7025                 unuse_block_rsv(root->fs_info, block_rsv, blocksize);
7026                 return ERR_PTR(ret);
7027         }
7028
7029         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
7030                                     blocksize, level);
7031         BUG_ON(IS_ERR(buf)); /* -ENOMEM */
7032
7033         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
7034                 if (parent == 0)
7035                         parent = ins.objectid;
7036                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
7037         } else
7038                 BUG_ON(parent > 0);
7039
7040         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
7041                 struct btrfs_delayed_extent_op *extent_op;
7042                 extent_op = btrfs_alloc_delayed_extent_op();
7043                 BUG_ON(!extent_op); /* -ENOMEM */
7044                 if (key)
7045                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
7046                 else
7047                         memset(&extent_op->key, 0, sizeof(extent_op->key));
7048                 extent_op->flags_to_set = flags;
7049                 if (skinny_metadata)
7050                         extent_op->update_key = 0;
7051                 else
7052                         extent_op->update_key = 1;
7053                 extent_op->update_flags = 1;
7054                 extent_op->is_data = 0;
7055                 extent_op->level = level;
7056
7057                 ret = btrfs_add_delayed_tree_ref(root->fs_info, trans,
7058                                         ins.objectid,
7059                                         ins.offset, parent, root_objectid,
7060                                         level, BTRFS_ADD_DELAYED_EXTENT,
7061                                         extent_op, 0);
7062                 BUG_ON(ret); /* -ENOMEM */
7063         }
7064         return buf;
7065 }
7066
7067 struct walk_control {
7068         u64 refs[BTRFS_MAX_LEVEL];
7069         u64 flags[BTRFS_MAX_LEVEL];
7070         struct btrfs_key update_progress;
7071         int stage;
7072         int level;
7073         int shared_level;
7074         int update_ref;
7075         int keep_locks;
7076         int reada_slot;
7077         int reada_count;
7078         int for_reloc;
7079 };
7080
7081 #define DROP_REFERENCE  1
7082 #define UPDATE_BACKREF  2
7083
7084 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
7085                                      struct btrfs_root *root,
7086                                      struct walk_control *wc,
7087                                      struct btrfs_path *path)
7088 {
7089         u64 bytenr;
7090         u64 generation;
7091         u64 refs;
7092         u64 flags;
7093         u32 nritems;
7094         u32 blocksize;
7095         struct btrfs_key key;
7096         struct extent_buffer *eb;
7097         int ret;
7098         int slot;
7099         int nread = 0;
7100
7101         if (path->slots[wc->level] < wc->reada_slot) {
7102                 wc->reada_count = wc->reada_count * 2 / 3;
7103                 wc->reada_count = max(wc->reada_count, 2);
7104         } else {
7105                 wc->reada_count = wc->reada_count * 3 / 2;
7106                 wc->reada_count = min_t(int, wc->reada_count,
7107                                         BTRFS_NODEPTRS_PER_BLOCK(root));
7108         }
7109
7110         eb = path->nodes[wc->level];
7111         nritems = btrfs_header_nritems(eb);
7112         blocksize = btrfs_level_size(root, wc->level - 1);
7113
7114         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
7115                 if (nread >= wc->reada_count)
7116                         break;
7117
7118                 cond_resched();
7119                 bytenr = btrfs_node_blockptr(eb, slot);
7120                 generation = btrfs_node_ptr_generation(eb, slot);
7121
7122                 if (slot == path->slots[wc->level])
7123                         goto reada;
7124
7125                 if (wc->stage == UPDATE_BACKREF &&
7126                     generation <= root->root_key.offset)
7127                         continue;
7128
7129                 /* We don't lock the tree block, it's OK to be racy here */
7130                 ret = btrfs_lookup_extent_info(trans, root, bytenr,
7131                                                wc->level - 1, 1, &refs,
7132                                                &flags);
7133                 /* We don't care about errors in readahead. */
7134                 if (ret < 0)
7135                         continue;
7136                 BUG_ON(refs == 0);
7137
7138                 if (wc->stage == DROP_REFERENCE) {
7139                         if (refs == 1)
7140                                 goto reada;
7141
7142                         if (wc->level == 1 &&
7143                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7144                                 continue;
7145                         if (!wc->update_ref ||
7146                             generation <= root->root_key.offset)
7147                                 continue;
7148                         btrfs_node_key_to_cpu(eb, &key, slot);
7149                         ret = btrfs_comp_cpu_keys(&key,
7150                                                   &wc->update_progress);
7151                         if (ret < 0)
7152                                 continue;
7153                 } else {
7154                         if (wc->level == 1 &&
7155                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7156                                 continue;
7157                 }
7158 reada:
7159                 ret = readahead_tree_block(root, bytenr, blocksize,
7160                                            generation);
7161                 if (ret)
7162                         break;
7163                 nread++;
7164         }
7165         wc->reada_slot = slot;
7166 }
7167
7168 /*
7169  * helper to process tree block while walking down the tree.
7170  *
7171  * when wc->stage == UPDATE_BACKREF, this function updates
7172  * back refs for pointers in the block.
7173  *
7174  * NOTE: return value 1 means we should stop walking down.
7175  */
7176 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
7177                                    struct btrfs_root *root,
7178                                    struct btrfs_path *path,
7179                                    struct walk_control *wc, int lookup_info)
7180 {
7181         int level = wc->level;
7182         struct extent_buffer *eb = path->nodes[level];
7183         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7184         int ret;
7185
7186         if (wc->stage == UPDATE_BACKREF &&
7187             btrfs_header_owner(eb) != root->root_key.objectid)
7188                 return 1;
7189
7190         /*
7191          * when reference count of tree block is 1, it won't increase
7192          * again. once full backref flag is set, we never clear it.
7193          */
7194         if (lookup_info &&
7195             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
7196              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
7197                 BUG_ON(!path->locks[level]);
7198                 ret = btrfs_lookup_extent_info(trans, root,
7199                                                eb->start, level, 1,
7200                                                &wc->refs[level],
7201                                                &wc->flags[level]);
7202                 BUG_ON(ret == -ENOMEM);
7203                 if (ret)
7204                         return ret;
7205                 BUG_ON(wc->refs[level] == 0);
7206         }
7207
7208         if (wc->stage == DROP_REFERENCE) {
7209                 if (wc->refs[level] > 1)
7210                         return 1;
7211
7212                 if (path->locks[level] && !wc->keep_locks) {
7213                         btrfs_tree_unlock_rw(eb, path->locks[level]);
7214                         path->locks[level] = 0;
7215                 }
7216                 return 0;
7217         }
7218
7219         /* wc->stage == UPDATE_BACKREF */
7220         if (!(wc->flags[level] & flag)) {
7221                 BUG_ON(!path->locks[level]);
7222                 ret = btrfs_inc_ref(trans, root, eb, 1, wc->for_reloc);
7223                 BUG_ON(ret); /* -ENOMEM */
7224                 ret = btrfs_dec_ref(trans, root, eb, 0, wc->for_reloc);
7225                 BUG_ON(ret); /* -ENOMEM */
7226                 ret = btrfs_set_disk_extent_flags(trans, root, eb->start,
7227                                                   eb->len, flag,
7228                                                   btrfs_header_level(eb), 0);
7229                 BUG_ON(ret); /* -ENOMEM */
7230                 wc->flags[level] |= flag;
7231         }
7232
7233         /*
7234          * the block is shared by multiple trees, so it's not good to
7235          * keep the tree lock
7236          */
7237         if (path->locks[level] && level > 0) {
7238                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7239                 path->locks[level] = 0;
7240         }
7241         return 0;
7242 }
7243
7244 /*
7245  * helper to process tree block pointer.
7246  *
7247  * when wc->stage == DROP_REFERENCE, this function checks
7248  * reference count of the block pointed to. if the block
7249  * is shared and we need update back refs for the subtree
7250  * rooted at the block, this function changes wc->stage to
7251  * UPDATE_BACKREF. if the block is shared and there is no
7252  * need to update back, this function drops the reference
7253  * to the block.
7254  *
7255  * NOTE: return value 1 means we should stop walking down.
7256  */
7257 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
7258                                  struct btrfs_root *root,
7259                                  struct btrfs_path *path,
7260                                  struct walk_control *wc, int *lookup_info)
7261 {
7262         u64 bytenr;
7263         u64 generation;
7264         u64 parent;
7265         u32 blocksize;
7266         struct btrfs_key key;
7267         struct extent_buffer *next;
7268         int level = wc->level;
7269         int reada = 0;
7270         int ret = 0;
7271
7272         generation = btrfs_node_ptr_generation(path->nodes[level],
7273                                                path->slots[level]);
7274         /*
7275          * if the lower level block was created before the snapshot
7276          * was created, we know there is no need to update back refs
7277          * for the subtree
7278          */
7279         if (wc->stage == UPDATE_BACKREF &&
7280             generation <= root->root_key.offset) {
7281                 *lookup_info = 1;
7282                 return 1;
7283         }
7284
7285         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
7286         blocksize = btrfs_level_size(root, level - 1);
7287
7288         next = btrfs_find_tree_block(root, bytenr, blocksize);
7289         if (!next) {
7290                 next = btrfs_find_create_tree_block(root, bytenr, blocksize);
7291                 if (!next)
7292                         return -ENOMEM;
7293                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
7294                                                level - 1);
7295                 reada = 1;
7296         }
7297         btrfs_tree_lock(next);
7298         btrfs_set_lock_blocking(next);
7299
7300         ret = btrfs_lookup_extent_info(trans, root, bytenr, level - 1, 1,
7301                                        &wc->refs[level - 1],
7302                                        &wc->flags[level - 1]);
7303         if (ret < 0) {
7304                 btrfs_tree_unlock(next);
7305                 return ret;
7306         }
7307
7308         if (unlikely(wc->refs[level - 1] == 0)) {
7309                 btrfs_err(root->fs_info, "Missing references.");
7310                 BUG();
7311         }
7312         *lookup_info = 0;
7313
7314         if (wc->stage == DROP_REFERENCE) {
7315                 if (wc->refs[level - 1] > 1) {
7316                         if (level == 1 &&
7317                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7318                                 goto skip;
7319
7320                         if (!wc->update_ref ||
7321                             generation <= root->root_key.offset)
7322                                 goto skip;
7323
7324                         btrfs_node_key_to_cpu(path->nodes[level], &key,
7325                                               path->slots[level]);
7326                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
7327                         if (ret < 0)
7328                                 goto skip;
7329
7330                         wc->stage = UPDATE_BACKREF;
7331                         wc->shared_level = level - 1;
7332                 }
7333         } else {
7334                 if (level == 1 &&
7335                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
7336                         goto skip;
7337         }
7338
7339         if (!btrfs_buffer_uptodate(next, generation, 0)) {
7340                 btrfs_tree_unlock(next);
7341                 free_extent_buffer(next);
7342                 next = NULL;
7343                 *lookup_info = 1;
7344         }
7345
7346         if (!next) {
7347                 if (reada && level == 1)
7348                         reada_walk_down(trans, root, wc, path);
7349                 next = read_tree_block(root, bytenr, blocksize, generation);
7350                 if (!next || !extent_buffer_uptodate(next)) {
7351                         free_extent_buffer(next);
7352                         return -EIO;
7353                 }
7354                 btrfs_tree_lock(next);
7355                 btrfs_set_lock_blocking(next);
7356         }
7357
7358         level--;
7359         BUG_ON(level != btrfs_header_level(next));
7360         path->nodes[level] = next;
7361         path->slots[level] = 0;
7362         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7363         wc->level = level;
7364         if (wc->level == 1)
7365                 wc->reada_slot = 0;
7366         return 0;
7367 skip:
7368         wc->refs[level - 1] = 0;
7369         wc->flags[level - 1] = 0;
7370         if (wc->stage == DROP_REFERENCE) {
7371                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
7372                         parent = path->nodes[level]->start;
7373                 } else {
7374                         BUG_ON(root->root_key.objectid !=
7375                                btrfs_header_owner(path->nodes[level]));
7376                         parent = 0;
7377                 }
7378
7379                 ret = btrfs_free_extent(trans, root, bytenr, blocksize, parent,
7380                                 root->root_key.objectid, level - 1, 0, 0);
7381                 BUG_ON(ret); /* -ENOMEM */
7382         }
7383         btrfs_tree_unlock(next);
7384         free_extent_buffer(next);
7385         *lookup_info = 1;
7386         return 1;
7387 }
7388
7389 /*
7390  * helper to process tree block while walking up the tree.
7391  *
7392  * when wc->stage == DROP_REFERENCE, this function drops
7393  * reference count on the block.
7394  *
7395  * when wc->stage == UPDATE_BACKREF, this function changes
7396  * wc->stage back to DROP_REFERENCE if we changed wc->stage
7397  * to UPDATE_BACKREF previously while processing the block.
7398  *
7399  * NOTE: return value 1 means we should stop walking up.
7400  */
7401 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
7402                                  struct btrfs_root *root,
7403                                  struct btrfs_path *path,
7404                                  struct walk_control *wc)
7405 {
7406         int ret;
7407         int level = wc->level;
7408         struct extent_buffer *eb = path->nodes[level];
7409         u64 parent = 0;
7410
7411         if (wc->stage == UPDATE_BACKREF) {
7412                 BUG_ON(wc->shared_level < level);
7413                 if (level < wc->shared_level)
7414                         goto out;
7415
7416                 ret = find_next_key(path, level + 1, &wc->update_progress);
7417                 if (ret > 0)
7418                         wc->update_ref = 0;
7419
7420                 wc->stage = DROP_REFERENCE;
7421                 wc->shared_level = -1;
7422                 path->slots[level] = 0;
7423
7424                 /*
7425                  * check reference count again if the block isn't locked.
7426                  * we should start walking down the tree again if reference
7427                  * count is one.
7428                  */
7429                 if (!path->locks[level]) {
7430                         BUG_ON(level == 0);
7431                         btrfs_tree_lock(eb);
7432                         btrfs_set_lock_blocking(eb);
7433                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7434
7435                         ret = btrfs_lookup_extent_info(trans, root,
7436                                                        eb->start, level, 1,
7437                                                        &wc->refs[level],
7438                                                        &wc->flags[level]);
7439                         if (ret < 0) {
7440                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7441                                 path->locks[level] = 0;
7442                                 return ret;
7443                         }
7444                         BUG_ON(wc->refs[level] == 0);
7445                         if (wc->refs[level] == 1) {
7446                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
7447                                 path->locks[level] = 0;
7448                                 return 1;
7449                         }
7450                 }
7451         }
7452
7453         /* wc->stage == DROP_REFERENCE */
7454         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
7455
7456         if (wc->refs[level] == 1) {
7457                 if (level == 0) {
7458                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7459                                 ret = btrfs_dec_ref(trans, root, eb, 1,
7460                                                     wc->for_reloc);
7461                         else
7462                                 ret = btrfs_dec_ref(trans, root, eb, 0,
7463                                                     wc->for_reloc);
7464                         BUG_ON(ret); /* -ENOMEM */
7465                 }
7466                 /* make block locked assertion in clean_tree_block happy */
7467                 if (!path->locks[level] &&
7468                     btrfs_header_generation(eb) == trans->transid) {
7469                         btrfs_tree_lock(eb);
7470                         btrfs_set_lock_blocking(eb);
7471                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7472                 }
7473                 clean_tree_block(trans, root, eb);
7474         }
7475
7476         if (eb == root->node) {
7477                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7478                         parent = eb->start;
7479                 else
7480                         BUG_ON(root->root_key.objectid !=
7481                                btrfs_header_owner(eb));
7482         } else {
7483                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
7484                         parent = path->nodes[level + 1]->start;
7485                 else
7486                         BUG_ON(root->root_key.objectid !=
7487                                btrfs_header_owner(path->nodes[level + 1]));
7488         }
7489
7490         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
7491 out:
7492         wc->refs[level] = 0;
7493         wc->flags[level] = 0;
7494         return 0;
7495 }
7496
7497 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
7498                                    struct btrfs_root *root,
7499                                    struct btrfs_path *path,
7500                                    struct walk_control *wc)
7501 {
7502         int level = wc->level;
7503         int lookup_info = 1;
7504         int ret;
7505
7506         while (level >= 0) {
7507                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
7508                 if (ret > 0)
7509                         break;
7510
7511                 if (level == 0)
7512                         break;
7513
7514                 if (path->slots[level] >=
7515                     btrfs_header_nritems(path->nodes[level]))
7516                         break;
7517
7518                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
7519                 if (ret > 0) {
7520                         path->slots[level]++;
7521                         continue;
7522                 } else if (ret < 0)
7523                         return ret;
7524                 level = wc->level;
7525         }
7526         return 0;
7527 }
7528
7529 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
7530                                  struct btrfs_root *root,
7531                                  struct btrfs_path *path,
7532                                  struct walk_control *wc, int max_level)
7533 {
7534         int level = wc->level;
7535         int ret;
7536
7537         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
7538         while (level < max_level && path->nodes[level]) {
7539                 wc->level = level;
7540                 if (path->slots[level] + 1 <
7541                     btrfs_header_nritems(path->nodes[level])) {
7542                         path->slots[level]++;
7543                         return 0;
7544                 } else {
7545                         ret = walk_up_proc(trans, root, path, wc);
7546                         if (ret > 0)
7547                                 return 0;
7548
7549                         if (path->locks[level]) {
7550                                 btrfs_tree_unlock_rw(path->nodes[level],
7551                                                      path->locks[level]);
7552                                 path->locks[level] = 0;
7553                         }
7554                         free_extent_buffer(path->nodes[level]);
7555                         path->nodes[level] = NULL;
7556                         level++;
7557                 }
7558         }
7559         return 1;
7560 }
7561
7562 /*
7563  * drop a subvolume tree.
7564  *
7565  * this function traverses the tree freeing any blocks that only
7566  * referenced by the tree.
7567  *
7568  * when a shared tree block is found. this function decreases its
7569  * reference count by one. if update_ref is true, this function
7570  * also make sure backrefs for the shared block and all lower level
7571  * blocks are properly updated.
7572  *
7573  * If called with for_reloc == 0, may exit early with -EAGAIN
7574  */
7575 int btrfs_drop_snapshot(struct btrfs_root *root,
7576                          struct btrfs_block_rsv *block_rsv, int update_ref,
7577                          int for_reloc)
7578 {
7579         struct btrfs_path *path;
7580         struct btrfs_trans_handle *trans;
7581         struct btrfs_root *tree_root = root->fs_info->tree_root;
7582         struct btrfs_root_item *root_item = &root->root_item;
7583         struct walk_control *wc;
7584         struct btrfs_key key;
7585         int err = 0;
7586         int ret;
7587         int level;
7588         bool root_dropped = false;
7589
7590         path = btrfs_alloc_path();
7591         if (!path) {
7592                 err = -ENOMEM;
7593                 goto out;
7594         }
7595
7596         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7597         if (!wc) {
7598                 btrfs_free_path(path);
7599                 err = -ENOMEM;
7600                 goto out;
7601         }
7602
7603         trans = btrfs_start_transaction(tree_root, 0);
7604         if (IS_ERR(trans)) {
7605                 err = PTR_ERR(trans);
7606                 goto out_free;
7607         }
7608
7609         if (block_rsv)
7610                 trans->block_rsv = block_rsv;
7611
7612         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
7613                 level = btrfs_header_level(root->node);
7614                 path->nodes[level] = btrfs_lock_root_node(root);
7615                 btrfs_set_lock_blocking(path->nodes[level]);
7616                 path->slots[level] = 0;
7617                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7618                 memset(&wc->update_progress, 0,
7619                        sizeof(wc->update_progress));
7620         } else {
7621                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
7622                 memcpy(&wc->update_progress, &key,
7623                        sizeof(wc->update_progress));
7624
7625                 level = root_item->drop_level;
7626                 BUG_ON(level == 0);
7627                 path->lowest_level = level;
7628                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
7629                 path->lowest_level = 0;
7630                 if (ret < 0) {
7631                         err = ret;
7632                         goto out_end_trans;
7633                 }
7634                 WARN_ON(ret > 0);
7635
7636                 /*
7637                  * unlock our path, this is safe because only this
7638                  * function is allowed to delete this snapshot
7639                  */
7640                 btrfs_unlock_up_safe(path, 0);
7641
7642                 level = btrfs_header_level(root->node);
7643                 while (1) {
7644                         btrfs_tree_lock(path->nodes[level]);
7645                         btrfs_set_lock_blocking(path->nodes[level]);
7646                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7647
7648                         ret = btrfs_lookup_extent_info(trans, root,
7649                                                 path->nodes[level]->start,
7650                                                 level, 1, &wc->refs[level],
7651                                                 &wc->flags[level]);
7652                         if (ret < 0) {
7653                                 err = ret;
7654                                 goto out_end_trans;
7655                         }
7656                         BUG_ON(wc->refs[level] == 0);
7657
7658                         if (level == root_item->drop_level)
7659                                 break;
7660
7661                         btrfs_tree_unlock(path->nodes[level]);
7662                         path->locks[level] = 0;
7663                         WARN_ON(wc->refs[level] != 1);
7664                         level--;
7665                 }
7666         }
7667
7668         wc->level = level;
7669         wc->shared_level = -1;
7670         wc->stage = DROP_REFERENCE;
7671         wc->update_ref = update_ref;
7672         wc->keep_locks = 0;
7673         wc->for_reloc = for_reloc;
7674         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7675
7676         while (1) {
7677
7678                 ret = walk_down_tree(trans, root, path, wc);
7679                 if (ret < 0) {
7680                         err = ret;
7681                         break;
7682                 }
7683
7684                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
7685                 if (ret < 0) {
7686                         err = ret;
7687                         break;
7688                 }
7689
7690                 if (ret > 0) {
7691                         BUG_ON(wc->stage != DROP_REFERENCE);
7692                         break;
7693                 }
7694
7695                 if (wc->stage == DROP_REFERENCE) {
7696                         level = wc->level;
7697                         btrfs_node_key(path->nodes[level],
7698                                        &root_item->drop_progress,
7699                                        path->slots[level]);
7700                         root_item->drop_level = level;
7701                 }
7702
7703                 BUG_ON(wc->level == 0);
7704                 if (btrfs_should_end_transaction(trans, tree_root) ||
7705                     (!for_reloc && btrfs_need_cleaner_sleep(root))) {
7706                         ret = btrfs_update_root(trans, tree_root,
7707                                                 &root->root_key,
7708                                                 root_item);
7709                         if (ret) {
7710                                 btrfs_abort_transaction(trans, tree_root, ret);
7711                                 err = ret;
7712                                 goto out_end_trans;
7713                         }
7714
7715                         btrfs_end_transaction_throttle(trans, tree_root);
7716                         if (!for_reloc && btrfs_need_cleaner_sleep(root)) {
7717                                 pr_debug("btrfs: drop snapshot early exit\n");
7718                                 err = -EAGAIN;
7719                                 goto out_free;
7720                         }
7721
7722                         trans = btrfs_start_transaction(tree_root, 0);
7723                         if (IS_ERR(trans)) {
7724                                 err = PTR_ERR(trans);
7725                                 goto out_free;
7726                         }
7727                         if (block_rsv)
7728                                 trans->block_rsv = block_rsv;
7729                 }
7730         }
7731         btrfs_release_path(path);
7732         if (err)
7733                 goto out_end_trans;
7734
7735         ret = btrfs_del_root(trans, tree_root, &root->root_key);
7736         if (ret) {
7737                 btrfs_abort_transaction(trans, tree_root, ret);
7738                 goto out_end_trans;
7739         }
7740
7741         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
7742                 ret = btrfs_find_root(tree_root, &root->root_key, path,
7743                                       NULL, NULL);
7744                 if (ret < 0) {
7745                         btrfs_abort_transaction(trans, tree_root, ret);
7746                         err = ret;
7747                         goto out_end_trans;
7748                 } else if (ret > 0) {
7749                         /* if we fail to delete the orphan item this time
7750                          * around, it'll get picked up the next time.
7751                          *
7752                          * The most common failure here is just -ENOENT.
7753                          */
7754                         btrfs_del_orphan_item(trans, tree_root,
7755                                               root->root_key.objectid);
7756                 }
7757         }
7758
7759         if (root->in_radix) {
7760                 btrfs_drop_and_free_fs_root(tree_root->fs_info, root);
7761         } else {
7762                 free_extent_buffer(root->node);
7763                 free_extent_buffer(root->commit_root);
7764                 btrfs_put_fs_root(root);
7765         }
7766         root_dropped = true;
7767 out_end_trans:
7768         btrfs_end_transaction_throttle(trans, tree_root);
7769 out_free:
7770         kfree(wc);
7771         btrfs_free_path(path);
7772 out:
7773         /*
7774          * So if we need to stop dropping the snapshot for whatever reason we
7775          * need to make sure to add it back to the dead root list so that we
7776          * keep trying to do the work later.  This also cleans up roots if we
7777          * don't have it in the radix (like when we recover after a power fail
7778          * or unmount) so we don't leak memory.
7779          */
7780         if (!for_reloc && root_dropped == false)
7781                 btrfs_add_dead_root(root);
7782         if (err)
7783                 btrfs_std_error(root->fs_info, err);
7784         return err;
7785 }
7786
7787 /*
7788  * drop subtree rooted at tree block 'node'.
7789  *
7790  * NOTE: this function will unlock and release tree block 'node'
7791  * only used by relocation code
7792  */
7793 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
7794                         struct btrfs_root *root,
7795                         struct extent_buffer *node,
7796                         struct extent_buffer *parent)
7797 {
7798         struct btrfs_path *path;
7799         struct walk_control *wc;
7800         int level;
7801         int parent_level;
7802         int ret = 0;
7803         int wret;
7804
7805         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
7806
7807         path = btrfs_alloc_path();
7808         if (!path)
7809                 return -ENOMEM;
7810
7811         wc = kzalloc(sizeof(*wc), GFP_NOFS);
7812         if (!wc) {
7813                 btrfs_free_path(path);
7814                 return -ENOMEM;
7815         }
7816
7817         btrfs_assert_tree_locked(parent);
7818         parent_level = btrfs_header_level(parent);
7819         extent_buffer_get(parent);
7820         path->nodes[parent_level] = parent;
7821         path->slots[parent_level] = btrfs_header_nritems(parent);
7822
7823         btrfs_assert_tree_locked(node);
7824         level = btrfs_header_level(node);
7825         path->nodes[level] = node;
7826         path->slots[level] = 0;
7827         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
7828
7829         wc->refs[parent_level] = 1;
7830         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
7831         wc->level = level;
7832         wc->shared_level = -1;
7833         wc->stage = DROP_REFERENCE;
7834         wc->update_ref = 0;
7835         wc->keep_locks = 1;
7836         wc->for_reloc = 1;
7837         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(root);
7838
7839         while (1) {
7840                 wret = walk_down_tree(trans, root, path, wc);
7841                 if (wret < 0) {
7842                         ret = wret;
7843                         break;
7844                 }
7845
7846                 wret = walk_up_tree(trans, root, path, wc, parent_level);
7847                 if (wret < 0)
7848                         ret = wret;
7849                 if (wret != 0)
7850                         break;
7851         }
7852
7853         kfree(wc);
7854         btrfs_free_path(path);
7855         return ret;
7856 }
7857
7858 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
7859 {
7860         u64 num_devices;
7861         u64 stripped;
7862
7863         /*
7864          * if restripe for this chunk_type is on pick target profile and
7865          * return, otherwise do the usual balance
7866          */
7867         stripped = get_restripe_target(root->fs_info, flags);
7868         if (stripped)
7869                 return extended_to_chunk(stripped);
7870
7871         /*
7872          * we add in the count of missing devices because we want
7873          * to make sure that any RAID levels on a degraded FS
7874          * continue to be honored.
7875          */
7876         num_devices = root->fs_info->fs_devices->rw_devices +
7877                 root->fs_info->fs_devices->missing_devices;
7878
7879         stripped = BTRFS_BLOCK_GROUP_RAID0 |
7880                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
7881                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
7882
7883         if (num_devices == 1) {
7884                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7885                 stripped = flags & ~stripped;
7886
7887                 /* turn raid0 into single device chunks */
7888                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
7889                         return stripped;
7890
7891                 /* turn mirroring into duplication */
7892                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
7893                              BTRFS_BLOCK_GROUP_RAID10))
7894                         return stripped | BTRFS_BLOCK_GROUP_DUP;
7895         } else {
7896                 /* they already had raid on here, just return */
7897                 if (flags & stripped)
7898                         return flags;
7899
7900                 stripped |= BTRFS_BLOCK_GROUP_DUP;
7901                 stripped = flags & ~stripped;
7902
7903                 /* switch duplicated blocks with raid1 */
7904                 if (flags & BTRFS_BLOCK_GROUP_DUP)
7905                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
7906
7907                 /* this is drive concat, leave it alone */
7908         }
7909
7910         return flags;
7911 }
7912
7913 static int set_block_group_ro(struct btrfs_block_group_cache *cache, int force)
7914 {
7915         struct btrfs_space_info *sinfo = cache->space_info;
7916         u64 num_bytes;
7917         u64 min_allocable_bytes;
7918         int ret = -ENOSPC;
7919
7920
7921         /*
7922          * We need some metadata space and system metadata space for
7923          * allocating chunks in some corner cases until we force to set
7924          * it to be readonly.
7925          */
7926         if ((sinfo->flags &
7927              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
7928             !force)
7929                 min_allocable_bytes = 1 * 1024 * 1024;
7930         else
7931                 min_allocable_bytes = 0;
7932
7933         spin_lock(&sinfo->lock);
7934         spin_lock(&cache->lock);
7935
7936         if (cache->ro) {
7937                 ret = 0;
7938                 goto out;
7939         }
7940
7941         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
7942                     cache->bytes_super - btrfs_block_group_used(&cache->item);
7943
7944         if (sinfo->bytes_used + sinfo->bytes_reserved + sinfo->bytes_pinned +
7945             sinfo->bytes_may_use + sinfo->bytes_readonly + num_bytes +
7946             min_allocable_bytes <= sinfo->total_bytes) {
7947                 sinfo->bytes_readonly += num_bytes;
7948                 cache->ro = 1;
7949                 ret = 0;
7950         }
7951 out:
7952         spin_unlock(&cache->lock);
7953         spin_unlock(&sinfo->lock);
7954         return ret;
7955 }
7956
7957 int btrfs_set_block_group_ro(struct btrfs_root *root,
7958                              struct btrfs_block_group_cache *cache)
7959
7960 {
7961         struct btrfs_trans_handle *trans;
7962         u64 alloc_flags;
7963         int ret;
7964
7965         BUG_ON(cache->ro);
7966
7967         trans = btrfs_join_transaction(root);
7968         if (IS_ERR(trans))
7969                 return PTR_ERR(trans);
7970
7971         alloc_flags = update_block_group_flags(root, cache->flags);
7972         if (alloc_flags != cache->flags) {
7973                 ret = do_chunk_alloc(trans, root, alloc_flags,
7974                                      CHUNK_ALLOC_FORCE);
7975                 if (ret < 0)
7976                         goto out;
7977         }
7978
7979         ret = set_block_group_ro(cache, 0);
7980         if (!ret)
7981                 goto out;
7982         alloc_flags = get_alloc_profile(root, cache->space_info->flags);
7983         ret = do_chunk_alloc(trans, root, alloc_flags,
7984                              CHUNK_ALLOC_FORCE);
7985         if (ret < 0)
7986                 goto out;
7987         ret = set_block_group_ro(cache, 0);
7988 out:
7989         btrfs_end_transaction(trans, root);
7990         return ret;
7991 }
7992
7993 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
7994                             struct btrfs_root *root, u64 type)
7995 {
7996         u64 alloc_flags = get_alloc_profile(root, type);
7997         return do_chunk_alloc(trans, root, alloc_flags,
7998                               CHUNK_ALLOC_FORCE);
7999 }
8000
8001 /*
8002  * helper to account the unused space of all the readonly block group in the
8003  * list. takes mirrors into account.
8004  */
8005 static u64 __btrfs_get_ro_block_group_free_space(struct list_head *groups_list)
8006 {
8007         struct btrfs_block_group_cache *block_group;
8008         u64 free_bytes = 0;
8009         int factor;
8010
8011         list_for_each_entry(block_group, groups_list, list) {
8012                 spin_lock(&block_group->lock);
8013
8014                 if (!block_group->ro) {
8015                         spin_unlock(&block_group->lock);
8016                         continue;
8017                 }
8018
8019                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
8020                                           BTRFS_BLOCK_GROUP_RAID10 |
8021                                           BTRFS_BLOCK_GROUP_DUP))
8022                         factor = 2;
8023                 else
8024                         factor = 1;
8025
8026                 free_bytes += (block_group->key.offset -
8027                                btrfs_block_group_used(&block_group->item)) *
8028                                factor;
8029
8030                 spin_unlock(&block_group->lock);
8031         }
8032
8033         return free_bytes;
8034 }
8035
8036 /*
8037  * helper to account the unused space of all the readonly block group in the
8038  * space_info. takes mirrors into account.
8039  */
8040 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
8041 {
8042         int i;
8043         u64 free_bytes = 0;
8044
8045         spin_lock(&sinfo->lock);
8046
8047         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
8048                 if (!list_empty(&sinfo->block_groups[i]))
8049                         free_bytes += __btrfs_get_ro_block_group_free_space(
8050                                                 &sinfo->block_groups[i]);
8051
8052         spin_unlock(&sinfo->lock);
8053
8054         return free_bytes;
8055 }
8056
8057 void btrfs_set_block_group_rw(struct btrfs_root *root,
8058                               struct btrfs_block_group_cache *cache)
8059 {
8060         struct btrfs_space_info *sinfo = cache->space_info;
8061         u64 num_bytes;
8062
8063         BUG_ON(!cache->ro);
8064
8065         spin_lock(&sinfo->lock);
8066         spin_lock(&cache->lock);
8067         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
8068                     cache->bytes_super - btrfs_block_group_used(&cache->item);
8069         sinfo->bytes_readonly -= num_bytes;
8070         cache->ro = 0;
8071         spin_unlock(&cache->lock);
8072         spin_unlock(&sinfo->lock);
8073 }
8074
8075 /*
8076  * checks to see if its even possible to relocate this block group.
8077  *
8078  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
8079  * ok to go ahead and try.
8080  */
8081 int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr)
8082 {
8083         struct btrfs_block_group_cache *block_group;
8084         struct btrfs_space_info *space_info;
8085         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
8086         struct btrfs_device *device;
8087         struct btrfs_trans_handle *trans;
8088         u64 min_free;
8089         u64 dev_min = 1;
8090         u64 dev_nr = 0;
8091         u64 target;
8092         int index;
8093         int full = 0;
8094         int ret = 0;
8095
8096         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
8097
8098         /* odd, couldn't find the block group, leave it alone */
8099         if (!block_group)
8100                 return -1;
8101
8102         min_free = btrfs_block_group_used(&block_group->item);
8103
8104         /* no bytes used, we're good */
8105         if (!min_free)
8106                 goto out;
8107
8108         space_info = block_group->space_info;
8109         spin_lock(&space_info->lock);
8110
8111         full = space_info->full;
8112
8113         /*
8114          * if this is the last block group we have in this space, we can't
8115          * relocate it unless we're able to allocate a new chunk below.
8116          *
8117          * Otherwise, we need to make sure we have room in the space to handle
8118          * all of the extents from this block group.  If we can, we're good
8119          */
8120         if ((space_info->total_bytes != block_group->key.offset) &&
8121             (space_info->bytes_used + space_info->bytes_reserved +
8122              space_info->bytes_pinned + space_info->bytes_readonly +
8123              min_free < space_info->total_bytes)) {
8124                 spin_unlock(&space_info->lock);
8125                 goto out;
8126         }
8127         spin_unlock(&space_info->lock);
8128
8129         /*
8130          * ok we don't have enough space, but maybe we have free space on our
8131          * devices to allocate new chunks for relocation, so loop through our
8132          * alloc devices and guess if we have enough space.  if this block
8133          * group is going to be restriped, run checks against the target
8134          * profile instead of the current one.
8135          */
8136         ret = -1;
8137
8138         /*
8139          * index:
8140          *      0: raid10
8141          *      1: raid1
8142          *      2: dup
8143          *      3: raid0
8144          *      4: single
8145          */
8146         target = get_restripe_target(root->fs_info, block_group->flags);
8147         if (target) {
8148                 index = __get_raid_index(extended_to_chunk(target));
8149         } else {
8150                 /*
8151                  * this is just a balance, so if we were marked as full
8152                  * we know there is no space for a new chunk
8153                  */
8154                 if (full)
8155                         goto out;
8156
8157                 index = get_block_group_index(block_group);
8158         }
8159
8160         if (index == BTRFS_RAID_RAID10) {
8161                 dev_min = 4;
8162                 /* Divide by 2 */
8163                 min_free >>= 1;
8164         } else if (index == BTRFS_RAID_RAID1) {
8165                 dev_min = 2;
8166         } else if (index == BTRFS_RAID_DUP) {
8167                 /* Multiply by 2 */
8168                 min_free <<= 1;
8169         } else if (index == BTRFS_RAID_RAID0) {
8170                 dev_min = fs_devices->rw_devices;
8171                 do_div(min_free, dev_min);
8172         }
8173
8174         /* We need to do this so that we can look at pending chunks */
8175         trans = btrfs_join_transaction(root);
8176         if (IS_ERR(trans)) {
8177                 ret = PTR_ERR(trans);
8178                 goto out;
8179         }
8180
8181         mutex_lock(&root->fs_info->chunk_mutex);
8182         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
8183                 u64 dev_offset;
8184
8185                 /*
8186                  * check to make sure we can actually find a chunk with enough
8187                  * space to fit our block group in.
8188                  */
8189                 if (device->total_bytes > device->bytes_used + min_free &&
8190                     !device->is_tgtdev_for_dev_replace) {
8191                         ret = find_free_dev_extent(trans, device, min_free,
8192                                                    &dev_offset, NULL);
8193                         if (!ret)
8194                                 dev_nr++;
8195
8196                         if (dev_nr >= dev_min)
8197                                 break;
8198
8199                         ret = -1;
8200                 }
8201         }
8202         mutex_unlock(&root->fs_info->chunk_mutex);
8203         btrfs_end_transaction(trans, root);
8204 out:
8205         btrfs_put_block_group(block_group);
8206         return ret;
8207 }
8208
8209 static int find_first_block_group(struct btrfs_root *root,
8210                 struct btrfs_path *path, struct btrfs_key *key)
8211 {
8212         int ret = 0;
8213         struct btrfs_key found_key;
8214         struct extent_buffer *leaf;
8215         int slot;
8216
8217         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
8218         if (ret < 0)
8219                 goto out;
8220
8221         while (1) {
8222                 slot = path->slots[0];
8223                 leaf = path->nodes[0];
8224                 if (slot >= btrfs_header_nritems(leaf)) {
8225                         ret = btrfs_next_leaf(root, path);
8226                         if (ret == 0)
8227                                 continue;
8228                         if (ret < 0)
8229                                 goto out;
8230                         break;
8231                 }
8232                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
8233
8234                 if (found_key.objectid >= key->objectid &&
8235                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
8236                         ret = 0;
8237                         goto out;
8238                 }
8239                 path->slots[0]++;
8240         }
8241 out:
8242         return ret;
8243 }
8244
8245 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
8246 {
8247         struct btrfs_block_group_cache *block_group;
8248         u64 last = 0;
8249
8250         while (1) {
8251                 struct inode *inode;
8252
8253                 block_group = btrfs_lookup_first_block_group(info, last);
8254                 while (block_group) {
8255                         spin_lock(&block_group->lock);
8256                         if (block_group->iref)
8257                                 break;
8258                         spin_unlock(&block_group->lock);
8259                         block_group = next_block_group(info->tree_root,
8260                                                        block_group);
8261                 }
8262                 if (!block_group) {
8263                         if (last == 0)
8264                                 break;
8265                         last = 0;
8266                         continue;
8267                 }
8268
8269                 inode = block_group->inode;
8270                 block_group->iref = 0;
8271                 block_group->inode = NULL;
8272                 spin_unlock(&block_group->lock);
8273                 iput(inode);
8274                 last = block_group->key.objectid + block_group->key.offset;
8275                 btrfs_put_block_group(block_group);
8276         }
8277 }
8278
8279 int btrfs_free_block_groups(struct btrfs_fs_info *info)
8280 {
8281         struct btrfs_block_group_cache *block_group;
8282         struct btrfs_space_info *space_info;
8283         struct btrfs_caching_control *caching_ctl;
8284         struct rb_node *n;
8285
8286         down_write(&info->extent_commit_sem);
8287         while (!list_empty(&info->caching_block_groups)) {
8288                 caching_ctl = list_entry(info->caching_block_groups.next,
8289                                          struct btrfs_caching_control, list);
8290                 list_del(&caching_ctl->list);
8291                 put_caching_control(caching_ctl);
8292         }
8293         up_write(&info->extent_commit_sem);
8294
8295         spin_lock(&info->block_group_cache_lock);
8296         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
8297                 block_group = rb_entry(n, struct btrfs_block_group_cache,
8298                                        cache_node);
8299                 rb_erase(&block_group->cache_node,
8300                          &info->block_group_cache_tree);
8301                 spin_unlock(&info->block_group_cache_lock);
8302
8303                 down_write(&block_group->space_info->groups_sem);
8304                 list_del(&block_group->list);
8305                 up_write(&block_group->space_info->groups_sem);
8306
8307                 if (block_group->cached == BTRFS_CACHE_STARTED)
8308                         wait_block_group_cache_done(block_group);
8309
8310                 /*
8311                  * We haven't cached this block group, which means we could
8312                  * possibly have excluded extents on this block group.
8313                  */
8314                 if (block_group->cached == BTRFS_CACHE_NO ||
8315                     block_group->cached == BTRFS_CACHE_ERROR)
8316                         free_excluded_extents(info->extent_root, block_group);
8317
8318                 btrfs_remove_free_space_cache(block_group);
8319                 btrfs_put_block_group(block_group);
8320
8321                 spin_lock(&info->block_group_cache_lock);
8322         }
8323         spin_unlock(&info->block_group_cache_lock);
8324
8325         /* now that all the block groups are freed, go through and
8326          * free all the space_info structs.  This is only called during
8327          * the final stages of unmount, and so we know nobody is
8328          * using them.  We call synchronize_rcu() once before we start,
8329          * just to be on the safe side.
8330          */
8331         synchronize_rcu();
8332
8333         release_global_block_rsv(info);
8334
8335         while (!list_empty(&info->space_info)) {
8336                 space_info = list_entry(info->space_info.next,
8337                                         struct btrfs_space_info,
8338                                         list);
8339                 if (btrfs_test_opt(info->tree_root, ENOSPC_DEBUG)) {
8340                         if (WARN_ON(space_info->bytes_pinned > 0 ||
8341                             space_info->bytes_reserved > 0 ||
8342                             space_info->bytes_may_use > 0)) {
8343                                 dump_space_info(space_info, 0, 0);
8344                         }
8345                 }
8346                 percpu_counter_destroy(&space_info->total_bytes_pinned);
8347                 list_del(&space_info->list);
8348                 kfree(space_info);
8349         }
8350         return 0;
8351 }
8352
8353 static void __link_block_group(struct btrfs_space_info *space_info,
8354                                struct btrfs_block_group_cache *cache)
8355 {
8356         int index = get_block_group_index(cache);
8357
8358         down_write(&space_info->groups_sem);
8359         list_add_tail(&cache->list, &space_info->block_groups[index]);
8360         up_write(&space_info->groups_sem);
8361 }
8362
8363 int btrfs_read_block_groups(struct btrfs_root *root)
8364 {
8365         struct btrfs_path *path;
8366         int ret;
8367         struct btrfs_block_group_cache *cache;
8368         struct btrfs_fs_info *info = root->fs_info;
8369         struct btrfs_space_info *space_info;
8370         struct btrfs_key key;
8371         struct btrfs_key found_key;
8372         struct extent_buffer *leaf;
8373         int need_clear = 0;
8374         u64 cache_gen;
8375
8376         root = info->extent_root;
8377         key.objectid = 0;
8378         key.offset = 0;
8379         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
8380         path = btrfs_alloc_path();
8381         if (!path)
8382                 return -ENOMEM;
8383         path->reada = 1;
8384
8385         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
8386         if (btrfs_test_opt(root, SPACE_CACHE) &&
8387             btrfs_super_generation(root->fs_info->super_copy) != cache_gen)
8388                 need_clear = 1;
8389         if (btrfs_test_opt(root, CLEAR_CACHE))
8390                 need_clear = 1;
8391
8392         while (1) {
8393                 ret = find_first_block_group(root, path, &key);
8394                 if (ret > 0)
8395                         break;
8396                 if (ret != 0)
8397                         goto error;
8398                 leaf = path->nodes[0];
8399                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
8400                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
8401                 if (!cache) {
8402                         ret = -ENOMEM;
8403                         goto error;
8404                 }
8405                 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8406                                                 GFP_NOFS);
8407                 if (!cache->free_space_ctl) {
8408                         kfree(cache);
8409                         ret = -ENOMEM;
8410                         goto error;
8411                 }
8412
8413                 atomic_set(&cache->count, 1);
8414                 spin_lock_init(&cache->lock);
8415                 cache->fs_info = info;
8416                 INIT_LIST_HEAD(&cache->list);
8417                 INIT_LIST_HEAD(&cache->cluster_list);
8418
8419                 if (need_clear) {
8420                         /*
8421                          * When we mount with old space cache, we need to
8422                          * set BTRFS_DC_CLEAR and set dirty flag.
8423                          *
8424                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
8425                          *    truncate the old free space cache inode and
8426                          *    setup a new one.
8427                          * b) Setting 'dirty flag' makes sure that we flush
8428                          *    the new space cache info onto disk.
8429                          */
8430                         cache->disk_cache_state = BTRFS_DC_CLEAR;
8431                         if (btrfs_test_opt(root, SPACE_CACHE))
8432                                 cache->dirty = 1;
8433                 }
8434
8435                 read_extent_buffer(leaf, &cache->item,
8436                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
8437                                    sizeof(cache->item));
8438                 memcpy(&cache->key, &found_key, sizeof(found_key));
8439
8440                 key.objectid = found_key.objectid + found_key.offset;
8441                 btrfs_release_path(path);
8442                 cache->flags = btrfs_block_group_flags(&cache->item);
8443                 cache->sectorsize = root->sectorsize;
8444                 cache->full_stripe_len = btrfs_full_stripe_len(root,
8445                                                &root->fs_info->mapping_tree,
8446                                                found_key.objectid);
8447                 btrfs_init_free_space_ctl(cache);
8448
8449                 /*
8450                  * We need to exclude the super stripes now so that the space
8451                  * info has super bytes accounted for, otherwise we'll think
8452                  * we have more space than we actually do.
8453                  */
8454                 ret = exclude_super_stripes(root, cache);
8455                 if (ret) {
8456                         /*
8457                          * We may have excluded something, so call this just in
8458                          * case.
8459                          */
8460                         free_excluded_extents(root, cache);
8461                         kfree(cache->free_space_ctl);
8462                         kfree(cache);
8463                         goto error;
8464                 }
8465
8466                 /*
8467                  * check for two cases, either we are full, and therefore
8468                  * don't need to bother with the caching work since we won't
8469                  * find any space, or we are empty, and we can just add all
8470                  * the space in and be done with it.  This saves us _alot_ of
8471                  * time, particularly in the full case.
8472                  */
8473                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
8474                         cache->last_byte_to_unpin = (u64)-1;
8475                         cache->cached = BTRFS_CACHE_FINISHED;
8476                         free_excluded_extents(root, cache);
8477                 } else if (btrfs_block_group_used(&cache->item) == 0) {
8478                         cache->last_byte_to_unpin = (u64)-1;
8479                         cache->cached = BTRFS_CACHE_FINISHED;
8480                         add_new_free_space(cache, root->fs_info,
8481                                            found_key.objectid,
8482                                            found_key.objectid +
8483                                            found_key.offset);
8484                         free_excluded_extents(root, cache);
8485                 }
8486
8487                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
8488                 if (ret) {
8489                         btrfs_remove_free_space_cache(cache);
8490                         btrfs_put_block_group(cache);
8491                         goto error;
8492                 }
8493
8494                 ret = update_space_info(info, cache->flags, found_key.offset,
8495                                         btrfs_block_group_used(&cache->item),
8496                                         &space_info);
8497                 if (ret) {
8498                         btrfs_remove_free_space_cache(cache);
8499                         spin_lock(&info->block_group_cache_lock);
8500                         rb_erase(&cache->cache_node,
8501                                  &info->block_group_cache_tree);
8502                         spin_unlock(&info->block_group_cache_lock);
8503                         btrfs_put_block_group(cache);
8504                         goto error;
8505                 }
8506
8507                 cache->space_info = space_info;
8508                 spin_lock(&cache->space_info->lock);
8509                 cache->space_info->bytes_readonly += cache->bytes_super;
8510                 spin_unlock(&cache->space_info->lock);
8511
8512                 __link_block_group(space_info, cache);
8513
8514                 set_avail_alloc_bits(root->fs_info, cache->flags);
8515                 if (btrfs_chunk_readonly(root, cache->key.objectid))
8516                         set_block_group_ro(cache, 1);
8517         }
8518
8519         list_for_each_entry_rcu(space_info, &root->fs_info->space_info, list) {
8520                 if (!(get_alloc_profile(root, space_info->flags) &
8521                       (BTRFS_BLOCK_GROUP_RAID10 |
8522                        BTRFS_BLOCK_GROUP_RAID1 |
8523                        BTRFS_BLOCK_GROUP_RAID5 |
8524                        BTRFS_BLOCK_GROUP_RAID6 |
8525                        BTRFS_BLOCK_GROUP_DUP)))
8526                         continue;
8527                 /*
8528                  * avoid allocating from un-mirrored block group if there are
8529                  * mirrored block groups.
8530                  */
8531                 list_for_each_entry(cache,
8532                                 &space_info->block_groups[BTRFS_RAID_RAID0],
8533                                 list)
8534                         set_block_group_ro(cache, 1);
8535                 list_for_each_entry(cache,
8536                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
8537                                 list)
8538                         set_block_group_ro(cache, 1);
8539         }
8540
8541         init_global_block_rsv(info);
8542         ret = 0;
8543 error:
8544         btrfs_free_path(path);
8545         return ret;
8546 }
8547
8548 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
8549                                        struct btrfs_root *root)
8550 {
8551         struct btrfs_block_group_cache *block_group, *tmp;
8552         struct btrfs_root *extent_root = root->fs_info->extent_root;
8553         struct btrfs_block_group_item item;
8554         struct btrfs_key key;
8555         int ret = 0;
8556
8557         list_for_each_entry_safe(block_group, tmp, &trans->new_bgs,
8558                                  new_bg_list) {
8559                 list_del_init(&block_group->new_bg_list);
8560
8561                 if (ret)
8562                         continue;
8563
8564                 spin_lock(&block_group->lock);
8565                 memcpy(&item, &block_group->item, sizeof(item));
8566                 memcpy(&key, &block_group->key, sizeof(key));
8567                 spin_unlock(&block_group->lock);
8568
8569                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
8570                                         sizeof(item));
8571                 if (ret)
8572                         btrfs_abort_transaction(trans, extent_root, ret);
8573                 ret = btrfs_finish_chunk_alloc(trans, extent_root,
8574                                                key.objectid, key.offset);
8575                 if (ret)
8576                         btrfs_abort_transaction(trans, extent_root, ret);
8577         }
8578 }
8579
8580 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
8581                            struct btrfs_root *root, u64 bytes_used,
8582                            u64 type, u64 chunk_objectid, u64 chunk_offset,
8583                            u64 size)
8584 {
8585         int ret;
8586         struct btrfs_root *extent_root;
8587         struct btrfs_block_group_cache *cache;
8588
8589         extent_root = root->fs_info->extent_root;
8590
8591         root->fs_info->last_trans_log_full_commit = trans->transid;
8592
8593         cache = kzalloc(sizeof(*cache), GFP_NOFS);
8594         if (!cache)
8595                 return -ENOMEM;
8596         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
8597                                         GFP_NOFS);
8598         if (!cache->free_space_ctl) {
8599                 kfree(cache);
8600                 return -ENOMEM;
8601         }
8602
8603         cache->key.objectid = chunk_offset;
8604         cache->key.offset = size;
8605         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
8606         cache->sectorsize = root->sectorsize;
8607         cache->fs_info = root->fs_info;
8608         cache->full_stripe_len = btrfs_full_stripe_len(root,
8609                                                &root->fs_info->mapping_tree,
8610                                                chunk_offset);
8611
8612         atomic_set(&cache->count, 1);
8613         spin_lock_init(&cache->lock);
8614         INIT_LIST_HEAD(&cache->list);
8615         INIT_LIST_HEAD(&cache->cluster_list);
8616         INIT_LIST_HEAD(&cache->new_bg_list);
8617
8618         btrfs_init_free_space_ctl(cache);
8619
8620         btrfs_set_block_group_used(&cache->item, bytes_used);
8621         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
8622         cache->flags = type;
8623         btrfs_set_block_group_flags(&cache->item, type);
8624
8625         cache->last_byte_to_unpin = (u64)-1;
8626         cache->cached = BTRFS_CACHE_FINISHED;
8627         ret = exclude_super_stripes(root, cache);
8628         if (ret) {
8629                 /*
8630                  * We may have excluded something, so call this just in
8631                  * case.
8632                  */
8633                 free_excluded_extents(root, cache);
8634                 kfree(cache->free_space_ctl);
8635                 kfree(cache);
8636                 return ret;
8637         }
8638
8639         add_new_free_space(cache, root->fs_info, chunk_offset,
8640                            chunk_offset + size);
8641
8642         free_excluded_extents(root, cache);
8643
8644         ret = btrfs_add_block_group_cache(root->fs_info, cache);
8645         if (ret) {
8646                 btrfs_remove_free_space_cache(cache);
8647                 btrfs_put_block_group(cache);
8648                 return ret;
8649         }
8650
8651         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
8652                                 &cache->space_info);
8653         if (ret) {
8654                 btrfs_remove_free_space_cache(cache);
8655                 spin_lock(&root->fs_info->block_group_cache_lock);
8656                 rb_erase(&cache->cache_node,
8657                          &root->fs_info->block_group_cache_tree);
8658                 spin_unlock(&root->fs_info->block_group_cache_lock);
8659                 btrfs_put_block_group(cache);
8660                 return ret;
8661         }
8662         update_global_block_rsv(root->fs_info);
8663
8664         spin_lock(&cache->space_info->lock);
8665         cache->space_info->bytes_readonly += cache->bytes_super;
8666         spin_unlock(&cache->space_info->lock);
8667
8668         __link_block_group(cache->space_info, cache);
8669
8670         list_add_tail(&cache->new_bg_list, &trans->new_bgs);
8671
8672         set_avail_alloc_bits(extent_root->fs_info, type);
8673
8674         return 0;
8675 }
8676
8677 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
8678 {
8679         u64 extra_flags = chunk_to_extended(flags) &
8680                                 BTRFS_EXTENDED_PROFILE_MASK;
8681
8682         write_seqlock(&fs_info->profiles_lock);
8683         if (flags & BTRFS_BLOCK_GROUP_DATA)
8684                 fs_info->avail_data_alloc_bits &= ~extra_flags;
8685         if (flags & BTRFS_BLOCK_GROUP_METADATA)
8686                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
8687         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
8688                 fs_info->avail_system_alloc_bits &= ~extra_flags;
8689         write_sequnlock(&fs_info->profiles_lock);
8690 }
8691
8692 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
8693                              struct btrfs_root *root, u64 group_start)
8694 {
8695         struct btrfs_path *path;
8696         struct btrfs_block_group_cache *block_group;
8697         struct btrfs_free_cluster *cluster;
8698         struct btrfs_root *tree_root = root->fs_info->tree_root;
8699         struct btrfs_key key;
8700         struct inode *inode;
8701         int ret;
8702         int index;
8703         int factor;
8704
8705         root = root->fs_info->extent_root;
8706
8707         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
8708         BUG_ON(!block_group);
8709         BUG_ON(!block_group->ro);
8710
8711         /*
8712          * Free the reserved super bytes from this block group before
8713          * remove it.
8714          */
8715         free_excluded_extents(root, block_group);
8716
8717         memcpy(&key, &block_group->key, sizeof(key));
8718         index = get_block_group_index(block_group);
8719         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
8720                                   BTRFS_BLOCK_GROUP_RAID1 |
8721                                   BTRFS_BLOCK_GROUP_RAID10))
8722                 factor = 2;
8723         else
8724                 factor = 1;
8725
8726         /* make sure this block group isn't part of an allocation cluster */
8727         cluster = &root->fs_info->data_alloc_cluster;
8728         spin_lock(&cluster->refill_lock);
8729         btrfs_return_cluster_to_free_space(block_group, cluster);
8730         spin_unlock(&cluster->refill_lock);
8731
8732         /*
8733          * make sure this block group isn't part of a metadata
8734          * allocation cluster
8735          */
8736         cluster = &root->fs_info->meta_alloc_cluster;
8737         spin_lock(&cluster->refill_lock);
8738         btrfs_return_cluster_to_free_space(block_group, cluster);
8739         spin_unlock(&cluster->refill_lock);
8740
8741         path = btrfs_alloc_path();
8742         if (!path) {
8743                 ret = -ENOMEM;
8744                 goto out;
8745         }
8746
8747         inode = lookup_free_space_inode(tree_root, block_group, path);
8748         if (!IS_ERR(inode)) {
8749                 ret = btrfs_orphan_add(trans, inode);
8750                 if (ret) {
8751                         btrfs_add_delayed_iput(inode);
8752                         goto out;
8753                 }
8754                 clear_nlink(inode);
8755                 /* One for the block groups ref */
8756                 spin_lock(&block_group->lock);
8757                 if (block_group->iref) {
8758                         block_group->iref = 0;
8759                         block_group->inode = NULL;
8760                         spin_unlock(&block_group->lock);
8761                         iput(inode);
8762                 } else {
8763                         spin_unlock(&block_group->lock);
8764                 }
8765                 /* One for our lookup ref */
8766                 btrfs_add_delayed_iput(inode);
8767         }
8768
8769         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
8770         key.offset = block_group->key.objectid;
8771         key.type = 0;
8772
8773         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
8774         if (ret < 0)
8775                 goto out;
8776         if (ret > 0)
8777                 btrfs_release_path(path);
8778         if (ret == 0) {
8779                 ret = btrfs_del_item(trans, tree_root, path);
8780                 if (ret)
8781                         goto out;
8782                 btrfs_release_path(path);
8783         }
8784
8785         spin_lock(&root->fs_info->block_group_cache_lock);
8786         rb_erase(&block_group->cache_node,
8787                  &root->fs_info->block_group_cache_tree);
8788
8789         if (root->fs_info->first_logical_byte == block_group->key.objectid)
8790                 root->fs_info->first_logical_byte = (u64)-1;
8791         spin_unlock(&root->fs_info->block_group_cache_lock);
8792
8793         down_write(&block_group->space_info->groups_sem);
8794         /*
8795          * we must use list_del_init so people can check to see if they
8796          * are still on the list after taking the semaphore
8797          */
8798         list_del_init(&block_group->list);
8799         if (list_empty(&block_group->space_info->block_groups[index]))
8800                 clear_avail_alloc_bits(root->fs_info, block_group->flags);
8801         up_write(&block_group->space_info->groups_sem);
8802
8803         if (block_group->cached == BTRFS_CACHE_STARTED)
8804                 wait_block_group_cache_done(block_group);
8805
8806         btrfs_remove_free_space_cache(block_group);
8807
8808         spin_lock(&block_group->space_info->lock);
8809         block_group->space_info->total_bytes -= block_group->key.offset;
8810         block_group->space_info->bytes_readonly -= block_group->key.offset;
8811         block_group->space_info->disk_total -= block_group->key.offset * factor;
8812         spin_unlock(&block_group->space_info->lock);
8813
8814         memcpy(&key, &block_group->key, sizeof(key));
8815
8816         btrfs_clear_space_info_full(root->fs_info);
8817
8818         btrfs_put_block_group(block_group);
8819         btrfs_put_block_group(block_group);
8820
8821         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
8822         if (ret > 0)
8823                 ret = -EIO;
8824         if (ret < 0)
8825                 goto out;
8826
8827         ret = btrfs_del_item(trans, root, path);
8828 out:
8829         btrfs_free_path(path);
8830         return ret;
8831 }
8832
8833 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
8834 {
8835         struct btrfs_space_info *space_info;
8836         struct btrfs_super_block *disk_super;
8837         u64 features;
8838         u64 flags;
8839         int mixed = 0;
8840         int ret;
8841
8842         disk_super = fs_info->super_copy;
8843         if (!btrfs_super_root(disk_super))
8844                 return 1;
8845
8846         features = btrfs_super_incompat_flags(disk_super);
8847         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
8848                 mixed = 1;
8849
8850         flags = BTRFS_BLOCK_GROUP_SYSTEM;
8851         ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8852         if (ret)
8853                 goto out;
8854
8855         if (mixed) {
8856                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
8857                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8858         } else {
8859                 flags = BTRFS_BLOCK_GROUP_METADATA;
8860                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8861                 if (ret)
8862                         goto out;
8863
8864                 flags = BTRFS_BLOCK_GROUP_DATA;
8865                 ret = update_space_info(fs_info, flags, 0, 0, &space_info);
8866         }
8867 out:
8868         return ret;
8869 }
8870
8871 int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
8872 {
8873         return unpin_extent_range(root, start, end);
8874 }
8875
8876 int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
8877                                u64 num_bytes, u64 *actual_bytes)
8878 {
8879         return btrfs_discard_extent(root, bytenr, num_bytes, actual_bytes);
8880 }
8881
8882 int btrfs_trim_fs(struct btrfs_root *root, struct fstrim_range *range)
8883 {
8884         struct btrfs_fs_info *fs_info = root->fs_info;
8885         struct btrfs_block_group_cache *cache = NULL;
8886         u64 group_trimmed;
8887         u64 start;
8888         u64 end;
8889         u64 trimmed = 0;
8890         u64 total_bytes = btrfs_super_total_bytes(fs_info->super_copy);
8891         int ret = 0;
8892
8893         /*
8894          * try to trim all FS space, our block group may start from non-zero.
8895          */
8896         if (range->len == total_bytes)
8897                 cache = btrfs_lookup_first_block_group(fs_info, range->start);
8898         else
8899                 cache = btrfs_lookup_block_group(fs_info, range->start);
8900
8901         while (cache) {
8902                 if (cache->key.objectid >= (range->start + range->len)) {
8903                         btrfs_put_block_group(cache);
8904                         break;
8905                 }
8906
8907                 start = max(range->start, cache->key.objectid);
8908                 end = min(range->start + range->len,
8909                                 cache->key.objectid + cache->key.offset);
8910
8911                 if (end - start >= range->minlen) {
8912                         if (!block_group_cache_done(cache)) {
8913                                 ret = cache_block_group(cache, 0);
8914                                 if (ret) {
8915                                         btrfs_put_block_group(cache);
8916                                         break;
8917                                 }
8918                                 ret = wait_block_group_cache_done(cache);
8919                                 if (ret) {
8920                                         btrfs_put_block_group(cache);
8921                                         break;
8922                                 }
8923                         }
8924                         ret = btrfs_trim_block_group(cache,
8925                                                      &group_trimmed,
8926                                                      start,
8927                                                      end,
8928                                                      range->minlen);
8929
8930                         trimmed += group_trimmed;
8931                         if (ret) {
8932                                 btrfs_put_block_group(cache);
8933                                 break;
8934                         }
8935                 }
8936
8937                 cache = next_block_group(fs_info->tree_root, cache);
8938         }
8939
8940         range->len = trimmed;
8941         return ret;
8942 }