SAFE public projects git trees. - safe/jmp/linux-2.6/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 "compat.h"
  24 #include "hash.h"
  25 #include "crc32c.h"
  26 #include "ctree.h"
  27 #include "disk-io.h"
  28 #include "print-tree.h"
  29 #include "transaction.h"
  30 #include "volumes.h"
  31 #include "locking.h"
  32 #include "ref-cache.h"
  33
  34 #define PENDING_EXTENT_INSERT 0
  35 #define PENDING_EXTENT_DELETE 1
  36 #define PENDING_BACKREF_UPDATE 2
  37
  38 struct pending_extent_op {
  39         int type;
  40         u64 bytenr;
  41         u64 num_bytes;
  42         u64 parent;
  43         u64 orig_parent;
  44         u64 generation;
  45         u64 orig_generation;
  46         int level;
  47         struct list_head list;
  48         int del;
  49 };
  50
  51 static int finish_current_insert(struct btrfs_trans_handle *trans,
  52                                  struct btrfs_root *extent_root, int all);
  53 static int del_pending_extents(struct btrfs_trans_handle *trans,
  54                                struct btrfs_root *extent_root, int all);
  55 static int pin_down_bytes(struct btrfs_trans_handle *trans,
  56                           struct btrfs_root *root,
  57                           u64 bytenr, u64 num_bytes, int is_data);
  58 static int update_block_group(struct btrfs_trans_handle *trans,
  59                               struct btrfs_root *root,
  60                               u64 bytenr, u64 num_bytes, int alloc,
  61                               int mark_free);
  62
  63 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  64                           struct btrfs_root *extent_root, u64 alloc_bytes,
  65                           u64 flags, int force);
  66
  67 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  68 {
  69         return (cache->flags & bits) == bits;
  70 }
  71
  72 /*
  73  * this adds the block group to the fs_info rb tree for the block group
  74  * cache
  75  */
  76 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
  77                                 struct btrfs_block_group_cache *block_group)
  78 {
  79         struct rb_node **p;
  80         struct rb_node *parent = NULL;
  81         struct btrfs_block_group_cache *cache;
  82
  83         spin_lock(&info->block_group_cache_lock);
  84         p = &info->block_group_cache_tree.rb_node;
  85
  86         while (*p) {
  87                 parent = *p;
  88                 cache = rb_entry(parent, struct btrfs_block_group_cache,
  89                                  cache_node);
  90                 if (block_group->key.objectid < cache->key.objectid) {
  91                         p = &(*p)->rb_left;
  92                 } else if (block_group->key.objectid > cache->key.objectid) {
  93                         p = &(*p)->rb_right;
  94                 } else {
  95                         spin_unlock(&info->block_group_cache_lock);
  96                         return -EEXIST;
  97                 }
  98         }
  99
 100         rb_link_node(&block_group->cache_node, parent, p);
 101         rb_insert_color(&block_group->cache_node,
 102                         &info->block_group_cache_tree);
 103         spin_unlock(&info->block_group_cache_lock);
 104
 105         return 0;
 106 }
 107
 108 /*
 109  * This will return the block group at or after bytenr if contains is 0, else
 110  * it will return the block group that contains the bytenr
 111  */
 112 static struct btrfs_block_group_cache *
 113 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 114                               int contains)
 115 {
 116         struct btrfs_block_group_cache *cache, *ret = NULL;
 117         struct rb_node *n;
 118         u64 end, start;
 119
 120         spin_lock(&info->block_group_cache_lock);
 121         n = info->block_group_cache_tree.rb_node;
 122
 123         while (n) {
 124                 cache = rb_entry(n, struct btrfs_block_group_cache,
 125                                  cache_node);
 126                 end = cache->key.objectid + cache->key.offset - 1;
 127                 start = cache->key.objectid;
 128
 129                 if (bytenr < start) {
 130                         if (!contains && (!ret || start < ret->key.objectid))
 131                                 ret = cache;
 132                         n = n->rb_left;
 133                 } else if (bytenr > start) {
 134                         if (contains && bytenr <= end) {
 135                                 ret = cache;
 136                                 break;
 137                         }
 138                         n = n->rb_right;
 139                 } else {
 140                         ret = cache;
 141                         break;
 142                 }
 143         }
 144         if (ret)
 145                 atomic_inc(&ret->count);
 146         spin_unlock(&info->block_group_cache_lock);
 147
 148         return ret;
 149 }
 150
 151 /*
 152  * this is only called by cache_block_group, since we could have freed extents
 153  * we need to check the pinned_extents for any extents that can't be used yet
 154  * since their free space will be released as soon as the transaction commits.
 155  */
 156 static int add_new_free_space(struct btrfs_block_group_cache *block_group,
 157                               struct btrfs_fs_info *info, u64 start, u64 end)
 158 {
 159         u64 extent_start, extent_end, size;
 160         int ret;
 161
 162         mutex_lock(&info->pinned_mutex);
 163         while (start < end) {
 164                 ret = find_first_extent_bit(&info->pinned_extents, start,
 165                                             &extent_start, &extent_end,
 166                                             EXTENT_DIRTY);
 167                 if (ret)
 168                         break;
 169
 170                 if (extent_start == start) {
 171                         start = extent_end + 1;
 172                 } else if (extent_start > start && extent_start < end) {
 173                         size = extent_start - start;
 174                         ret = btrfs_add_free_space(block_group, start,
 175                                                    size);
 176                         BUG_ON(ret);
 177                         start = extent_end + 1;
 178                 } else {
 179                         break;
 180                 }
 181         }
 182
 183         if (start < end) {
 184                 size = end - start;
 185                 ret = btrfs_add_free_space(block_group, start, size);
 186                 BUG_ON(ret);
 187         }
 188         mutex_unlock(&info->pinned_mutex);
 189
 190         return 0;
 191 }
 192
 193 static int remove_sb_from_cache(struct btrfs_root *root,
 194                                 struct btrfs_block_group_cache *cache)
 195 {
 196         u64 bytenr;
 197         u64 *logical;
 198         int stripe_len;
 199         int i, nr, ret;
 200
 201         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 202                 bytenr = btrfs_sb_offset(i);
 203                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 204                                        cache->key.objectid, bytenr, 0,
 205                                        &logical, &nr, &stripe_len);
 206                 BUG_ON(ret);
 207                 while (nr--) {
 208                         btrfs_remove_free_space(cache, logical[nr],
 209                                                 stripe_len);
 210                 }
 211                 kfree(logical);
 212         }
 213         return 0;
 214 }
 215
 216 static int cache_block_group(struct btrfs_root *root,
 217                              struct btrfs_block_group_cache *block_group)
 218 {
 219         struct btrfs_path *path;
 220         int ret = 0;
 221         struct btrfs_key key;
 222         struct extent_buffer *leaf;
 223         int slot;
 224         u64 last;
 225
 226         if (!block_group)
 227                 return 0;
 228
 229         root = root->fs_info->extent_root;
 230
 231         if (block_group->cached)
 232                 return 0;
 233
 234         path = btrfs_alloc_path();
 235         if (!path)
 236                 return -ENOMEM;
 237
 238         path->reada = 2;
 239         /*
 240          * we get into deadlocks with paths held by callers of this function.
 241          * since the alloc_mutex is protecting things right now, just
 242          * skip the locking here
 243          */
 244         path->skip_locking = 1;
 245         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 246         key.objectid = last;
 247         key.offset = 0;
 248         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 249         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 250         if (ret < 0)
 251                 goto err;
 252
 253         while (1) {
 254                 leaf = path->nodes[0];
 255                 slot = path->slots[0];
 256                 if (slot >= btrfs_header_nritems(leaf)) {
 257                         ret = btrfs_next_leaf(root, path);
 258                         if (ret < 0)
 259                                 goto err;
 260                         if (ret == 0)
 261                                 continue;
 262                         else
 263                                 break;
 264                 }
 265                 btrfs_item_key_to_cpu(leaf, &key, slot);
 266                 if (key.objectid < block_group->key.objectid)
 267                         goto next;
 268
 269                 if (key.objectid >= block_group->key.objectid +
 270                     block_group->key.offset)
 271                         break;
 272
 273                 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
 274                         add_new_free_space(block_group, root->fs_info, last,
 275                                            key.objectid);
 276
 277                         last = key.objectid + key.offset;
 278                 }
 279 next:
 280                 path->slots[0]++;
 281         }
 282
 283         add_new_free_space(block_group, root->fs_info, last,
 284                            block_group->key.objectid +
 285                            block_group->key.offset);
 286
 287         remove_sb_from_cache(root, block_group);
 288         block_group->cached = 1;
 289         ret = 0;
 290 err:
 291         btrfs_free_path(path);
 292         return ret;
 293 }
 294
 295 /*
 296  * return the block group that starts at or after bytenr
 297  */
 298 static struct btrfs_block_group_cache *
 299 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 300 {
 301         struct btrfs_block_group_cache *cache;
 302
 303         cache = block_group_cache_tree_search(info, bytenr, 0);
 304
 305         return cache;
 306 }
 307
 308 /*
 309  * return the block group that contains teh given bytenr
 310  */
 311 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 312                                                  struct btrfs_fs_info *info,
 313                                                  u64 bytenr)
 314 {
 315         struct btrfs_block_group_cache *cache;
 316
 317         cache = block_group_cache_tree_search(info, bytenr, 1);
 318
 319         return cache;
 320 }
 321
 322 static inline void put_block_group(struct btrfs_block_group_cache *cache)
 323 {
 324         if (atomic_dec_and_test(&cache->count))
 325                 kfree(cache);
 326 }
 327
 328 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 329                                                   u64 flags)
 330 {
 331         struct list_head *head = &info->space_info;
 332         struct btrfs_space_info *found;
 333         list_for_each_entry(found, head, list) {
 334                 if (found->flags == flags)
 335                         return found;
 336         }
 337         return NULL;
 338 }
 339
 340 static u64 div_factor(u64 num, int factor)
 341 {
 342         if (factor == 10)
 343                 return num;
 344         num *= factor;
 345         do_div(num, 10);
 346         return num;
 347 }
 348
 349 u64 btrfs_find_block_group(struct btrfs_root *root,
 350                            u64 search_start, u64 search_hint, int owner)
 351 {
 352         struct btrfs_block_group_cache *cache;
 353         u64 used;
 354         u64 last = max(search_hint, search_start);
 355         u64 group_start = 0;
 356         int full_search = 0;
 357         int factor = 9;
 358         int wrapped = 0;
 359 again:
 360         while (1) {
 361                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 362                 if (!cache)
 363                         break;
 364
 365                 spin_lock(&cache->lock);
 366                 last = cache->key.objectid + cache->key.offset;
 367                 used = btrfs_block_group_used(&cache->item);
 368
 369                 if ((full_search || !cache->ro) &&
 370                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 371                         if (used + cache->pinned + cache->reserved <
 372                             div_factor(cache->key.offset, factor)) {
 373                                 group_start = cache->key.objectid;
 374                                 spin_unlock(&cache->lock);
 375                                 put_block_group(cache);
 376                                 goto found;
 377                         }
 378                 }
 379                 spin_unlock(&cache->lock);
 380                 put_block_group(cache);
 381                 cond_resched();
 382         }
 383         if (!wrapped) {
 384                 last = search_start;
 385                 wrapped = 1;
 386                 goto again;
 387         }
 388         if (!full_search && factor < 10) {
 389                 last = search_start;
 390                 full_search = 1;
 391                 factor = 10;
 392                 goto again;
 393         }
 394 found:
 395         return group_start;
 396 }
 397
 398 /* simple helper to search for an existing extent at a given offset */
 399 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 400 {
 401         int ret;
 402         struct btrfs_key key;
 403         struct btrfs_path *path;
 404
 405         path = btrfs_alloc_path();
 406         BUG_ON(!path);
 407         key.objectid = start;
 408         key.offset = len;
 409         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 410         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 411                                 0, 0);
 412         btrfs_free_path(path);
 413         return ret;
 414 }
 415
 416 /*
 417  * Back reference rules.  Back refs have three main goals:
 418  *
 419  * 1) differentiate between all holders of references to an extent so that
 420  *    when a reference is dropped we can make sure it was a valid reference
 421  *    before freeing the extent.
 422  *
 423  * 2) Provide enough information to quickly find the holders of an extent
 424  *    if we notice a given block is corrupted or bad.
 425  *
 426  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 427  *    maintenance.  This is actually the same as #2, but with a slightly
 428  *    different use case.
 429  *
 430  * File extents can be referenced by:
 431  *
 432  * - multiple snapshots, subvolumes, or different generations in one subvol
 433  * - different files inside a single subvolume
 434  * - different offsets inside a file (bookend extents in file.c)
 435  *
 436  * The extent ref structure has fields for:
 437  *
 438  * - Objectid of the subvolume root
 439  * - Generation number of the tree holding the reference
 440  * - objectid of the file holding the reference
 441  * - number of references holding by parent node (alway 1 for tree blocks)
 442  *
 443  * Btree leaf may hold multiple references to a file extent. In most cases,
 444  * these references are from same file and the corresponding offsets inside
 445  * the file are close together.
 446  *
 447  * When a file extent is allocated the fields are filled in:
 448  *     (root_key.objectid, trans->transid, inode objectid, 1)
 449  *
 450  * When a leaf is cow'd new references are added for every file extent found
 451  * in the leaf.  It looks similar to the create case, but trans->transid will
 452  * be different when the block is cow'd.
 453  *
 454  *     (root_key.objectid, trans->transid, inode objectid,
 455  *      number of references in the leaf)
 456  *
 457  * When a file extent is removed either during snapshot deletion or
 458  * file truncation, we find the corresponding back reference and check
 459  * the following fields:
 460  *
 461  *     (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
 462  *      inode objectid)
 463  *
 464  * Btree extents can be referenced by:
 465  *
 466  * - Different subvolumes
 467  * - Different generations of the same subvolume
 468  *
 469  * When a tree block is created, back references are inserted:
 470  *
 471  * (root->root_key.objectid, trans->transid, level, 1)
 472  *
 473  * When a tree block is cow'd, new back references are added for all the
 474  * blocks it points to. If the tree block isn't in reference counted root,
 475  * the old back references are removed. These new back references are of
 476  * the form (trans->transid will have increased since creation):
 477  *
 478  * (root->root_key.objectid, trans->transid, level, 1)
 479  *
 480  * When a backref is in deleting, the following fields are checked:
 481  *
 482  * if backref was for a tree root:
 483  *     (btrfs_header_owner(itself), btrfs_header_generation(itself), level)
 484  * else
 485  *     (btrfs_header_owner(parent), btrfs_header_generation(parent), level)
 486  *
 487  * Back Reference Key composing:
 488  *
 489  * The key objectid corresponds to the first byte in the extent, the key
 490  * type is set to BTRFS_EXTENT_REF_KEY, and the key offset is the first
 491  * byte of parent extent. If a extent is tree root, the key offset is set
 492  * to the key objectid.
 493  */
 494
 495 static noinline int lookup_extent_backref(struct btrfs_trans_handle *trans,
 496                                           struct btrfs_root *root,
 497                                           struct btrfs_path *path,
 498                                           u64 bytenr, u64 parent,
 499                                           u64 ref_root, u64 ref_generation,
 500                                           u64 owner_objectid, int del)
 501 {
 502         struct btrfs_key key;
 503         struct btrfs_extent_ref *ref;
 504         struct extent_buffer *leaf;
 505         u64 ref_objectid;
 506         int ret;
 507
 508         key.objectid = bytenr;
 509         key.type = BTRFS_EXTENT_REF_KEY;
 510         key.offset = parent;
 511
 512         ret = btrfs_search_slot(trans, root, &key, path, del ? -1 : 0, 1);
 513         if (ret < 0)
 514                 goto out;
 515         if (ret > 0) {
 516                 ret = -ENOENT;
 517                 goto out;
 518         }
 519
 520         leaf = path->nodes[0];
 521         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 522         ref_objectid = btrfs_ref_objectid(leaf, ref);
 523         if (btrfs_ref_root(leaf, ref) != ref_root ||
 524             btrfs_ref_generation(leaf, ref) != ref_generation ||
 525             (ref_objectid != owner_objectid &&
 526              ref_objectid != BTRFS_MULTIPLE_OBJECTIDS)) {
 527                 ret = -EIO;
 528                 WARN_ON(1);
 529                 goto out;
 530         }
 531         ret = 0;
 532 out:
 533         return ret;
 534 }
 535
 536 /*
 537  * updates all the backrefs that are pending on update_list for the
 538  * extent_root
 539  */
 540 static noinline int update_backrefs(struct btrfs_trans_handle *trans,
 541                                     struct btrfs_root *extent_root,
 542                                     struct btrfs_path *path,
 543                                     struct list_head *update_list)
 544 {
 545         struct btrfs_key key;
 546         struct btrfs_extent_ref *ref;
 547         struct btrfs_fs_info *info = extent_root->fs_info;
 548         struct pending_extent_op *op;
 549         struct extent_buffer *leaf;
 550         int ret = 0;
 551         struct list_head *cur = update_list->next;
 552         u64 ref_objectid;
 553         u64 ref_root = extent_root->root_key.objectid;
 554
 555         op = list_entry(cur, struct pending_extent_op, list);
 556
 557 search:
 558         key.objectid = op->bytenr;
 559         key.type = BTRFS_EXTENT_REF_KEY;
 560         key.offset = op->orig_parent;
 561
 562         ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 1);
 563         BUG_ON(ret);
 564
 565         leaf = path->nodes[0];
 566
 567 loop:
 568         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 569
 570         ref_objectid = btrfs_ref_objectid(leaf, ref);
 571
 572         if (btrfs_ref_root(leaf, ref) != ref_root ||
 573             btrfs_ref_generation(leaf, ref) != op->orig_generation ||
 574             (ref_objectid != op->level &&
 575              ref_objectid != BTRFS_MULTIPLE_OBJECTIDS)) {
 576                 printk(KERN_ERR "btrfs couldn't find %llu, parent %llu, "
 577                        "root %llu, owner %u\n",
 578                        (unsigned long long)op->bytenr,
 579                        (unsigned long long)op->orig_parent,
 580                        (unsigned long long)ref_root, op->level);
 581                 btrfs_print_leaf(extent_root, leaf);
 582                 BUG();
 583         }
 584
 585         key.objectid = op->bytenr;
 586         key.offset = op->parent;
 587         key.type = BTRFS_EXTENT_REF_KEY;
 588         ret = btrfs_set_item_key_safe(trans, extent_root, path, &key);
 589         BUG_ON(ret);
 590         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 591         btrfs_set_ref_generation(leaf, ref, op->generation);
 592
 593         cur = cur->next;
 594
 595         list_del_init(&op->list);
 596         unlock_extent(&info->extent_ins, op->bytenr,
 597                       op->bytenr + op->num_bytes - 1, GFP_NOFS);
 598         kfree(op);
 599
 600         if (cur == update_list) {
 601                 btrfs_mark_buffer_dirty(path->nodes[0]);
 602                 btrfs_release_path(extent_root, path);
 603                 goto out;
 604         }
 605
 606         op = list_entry(cur, struct pending_extent_op, list);
 607
 608         path->slots[0]++;
 609         while (path->slots[0] < btrfs_header_nritems(leaf)) {
 610                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 611                 if (key.objectid == op->bytenr &&
 612                     key.type == BTRFS_EXTENT_REF_KEY)
 613                         goto loop;
 614                 path->slots[0]++;
 615         }
 616
 617         btrfs_mark_buffer_dirty(path->nodes[0]);
 618         btrfs_release_path(extent_root, path);
 619         goto search;
 620
 621 out:
 622         return 0;
 623 }
 624
 625 static noinline int insert_extents(struct btrfs_trans_handle *trans,
 626                                    struct btrfs_root *extent_root,
 627                                    struct btrfs_path *path,
 628                                    struct list_head *insert_list, int nr)
 629 {
 630         struct btrfs_key *keys;
 631         u32 *data_size;
 632         struct pending_extent_op *op;
 633         struct extent_buffer *leaf;
 634         struct list_head *cur = insert_list->next;
 635         struct btrfs_fs_info *info = extent_root->fs_info;
 636         u64 ref_root = extent_root->root_key.objectid;
 637         int i = 0, last = 0, ret;
 638         int total = nr * 2;
 639
 640         if (!nr)
 641                 return 0;
 642
 643         keys = kzalloc(total * sizeof(struct btrfs_key), GFP_NOFS);
 644         if (!keys)
 645                 return -ENOMEM;
 646
 647         data_size = kzalloc(total * sizeof(u32), GFP_NOFS);
 648         if (!data_size) {
 649                 kfree(keys);
 650                 return -ENOMEM;
 651         }
 652
 653         list_for_each_entry(op, insert_list, list) {
 654                 keys[i].objectid = op->bytenr;
 655                 keys[i].offset = op->num_bytes;
 656                 keys[i].type = BTRFS_EXTENT_ITEM_KEY;
 657                 data_size[i] = sizeof(struct btrfs_extent_item);
 658                 i++;
 659
 660                 keys[i].objectid = op->bytenr;
 661                 keys[i].offset = op->parent;
 662                 keys[i].type = BTRFS_EXTENT_REF_KEY;
 663                 data_size[i] = sizeof(struct btrfs_extent_ref);
 664                 i++;
 665         }
 666
 667         op = list_entry(cur, struct pending_extent_op, list);
 668         i = 0;
 669         while (i < total) {
 670                 int c;
 671                 ret = btrfs_insert_some_items(trans, extent_root, path,
 672                                               keys+i, data_size+i, total-i);
 673                 BUG_ON(ret < 0);
 674
 675                 if (last && ret > 1)
 676                         BUG();
 677
 678                 leaf = path->nodes[0];
 679                 for (c = 0; c < ret; c++) {
 680                         int ref_first = keys[i].type == BTRFS_EXTENT_REF_KEY;
 681
 682                         /*
 683                          * if the first item we inserted was a backref, then
 684                          * the EXTENT_ITEM will be the odd c's, else it will
 685                          * be the even c's
 686                          */
 687                         if ((ref_first && (c % 2)) ||
 688                             (!ref_first && !(c % 2))) {
 689                                 struct btrfs_extent_item *itm;
 690
 691                                 itm = btrfs_item_ptr(leaf, path->slots[0] + c,
 692                                                      struct btrfs_extent_item);
 693                                 btrfs_set_extent_refs(path->nodes[0], itm, 1);
 694                                 op->del++;
 695                         } else {
 696                                 struct btrfs_extent_ref *ref;
 697
 698                                 ref = btrfs_item_ptr(leaf, path->slots[0] + c,
 699                                                      struct btrfs_extent_ref);
 700                                 btrfs_set_ref_root(leaf, ref, ref_root);
 701                                 btrfs_set_ref_generation(leaf, ref,
 702                                                          op->generation);
 703                                 btrfs_set_ref_objectid(leaf, ref, op->level);
 704                                 btrfs_set_ref_num_refs(leaf, ref, 1);
 705                                 op->del++;
 706                         }
 707
 708                         /*
 709                          * using del to see when its ok to free up the
 710                          * pending_extent_op.  In the case where we insert the
 711                          * last item on the list in order to help do batching
 712                          * we need to not free the extent op until we actually
 713                          * insert the extent_item
 714                          */
 715                         if (op->del == 2) {
 716                                 unlock_extent(&info->extent_ins, op->bytenr,
 717                                               op->bytenr + op->num_bytes - 1,
 718                                               GFP_NOFS);
 719                                 cur = cur->next;
 720                                 list_del_init(&op->list);
 721                                 kfree(op);
 722                                 if (cur != insert_list)
 723                                         op = list_entry(cur,
 724                                                 struct pending_extent_op,
 725                                                 list);
 726                         }
 727                 }
 728                 btrfs_mark_buffer_dirty(leaf);
 729                 btrfs_release_path(extent_root, path);
 730
 731                 /*
 732                  * Ok backref's and items usually go right next to eachother,
 733                  * but if we could only insert 1 item that means that we
 734                  * inserted on the end of a leaf, and we have no idea what may
 735                  * be on the next leaf so we just play it safe.  In order to
 736                  * try and help this case we insert the last thing on our
 737                  * insert list so hopefully it will end up being the last
 738                  * thing on the leaf and everything else will be before it,
 739                  * which will let us insert a whole bunch of items at the same
 740                  * time.
 741                  */
 742                 if (ret == 1 && !last && (i + ret < total)) {
 743                         /*
 744                          * last: where we will pick up the next time around
 745                          * i: our current key to insert, will be total - 1
 746                          * cur: the current op we are screwing with
 747                          * op: duh
 748                          */
 749                         last = i + ret;
 750                         i = total - 1;
 751                         cur = insert_list->prev;
 752                         op = list_entry(cur, struct pending_extent_op, list);
 753                 } else if (last) {
 754                         /*
 755                          * ok we successfully inserted the last item on the
 756                          * list, lets reset everything
 757                          *
 758                          * i: our current key to insert, so where we left off
 759                          *    last time
 760                          * last: done with this
 761                          * cur: the op we are messing with
 762                          * op: duh
 763                          * total: since we inserted the last key, we need to
 764                          *        decrement total so we dont overflow
 765                          */
 766                         i = last;
 767                         last = 0;
 768                         total--;
 769                         if (i < total) {
 770                                 cur = insert_list->next;
 771                                 op = list_entry(cur, struct pending_extent_op,
 772                                                 list);
 773                         }
 774                 } else {
 775                         i += ret;
 776                 }
 777
 778                 cond_resched();
 779         }
 780         ret = 0;
 781         kfree(keys);
 782         kfree(data_size);
 783         return ret;
 784 }
 785
 786 static noinline int insert_extent_backref(struct btrfs_trans_handle *trans,
 787                                           struct btrfs_root *root,
 788                                           struct btrfs_path *path,
 789                                           u64 bytenr, u64 parent,
 790                                           u64 ref_root, u64 ref_generation,
 791                                           u64 owner_objectid)
 792 {
 793         struct btrfs_key key;
 794         struct extent_buffer *leaf;
 795         struct btrfs_extent_ref *ref;
 796         u32 num_refs;
 797         int ret;
 798
 799         key.objectid = bytenr;
 800         key.type = BTRFS_EXTENT_REF_KEY;
 801         key.offset = parent;
 802
 803         ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*ref));
 804         if (ret == 0) {
 805                 leaf = path->nodes[0];
 806                 ref = btrfs_item_ptr(leaf, path->slots[0],
 807                                      struct btrfs_extent_ref);
 808                 btrfs_set_ref_root(leaf, ref, ref_root);
 809                 btrfs_set_ref_generation(leaf, ref, ref_generation);
 810                 btrfs_set_ref_objectid(leaf, ref, owner_objectid);
 811                 btrfs_set_ref_num_refs(leaf, ref, 1);
 812         } else if (ret == -EEXIST) {
 813                 u64 existing_owner;
 814                 BUG_ON(owner_objectid < BTRFS_FIRST_FREE_OBJECTID);
 815                 leaf = path->nodes[0];
 816                 ref = btrfs_item_ptr(leaf, path->slots[0],
 817                                      struct btrfs_extent_ref);
 818                 if (btrfs_ref_root(leaf, ref) != ref_root ||
 819                     btrfs_ref_generation(leaf, ref) != ref_generation) {
 820                         ret = -EIO;
 821                         WARN_ON(1);
 822                         goto out;
 823                 }
 824
 825                 num_refs = btrfs_ref_num_refs(leaf, ref);
 826                 BUG_ON(num_refs == 0);
 827                 btrfs_set_ref_num_refs(leaf, ref, num_refs + 1);
 828
 829                 existing_owner = btrfs_ref_objectid(leaf, ref);
 830                 if (existing_owner != owner_objectid &&
 831                     existing_owner != BTRFS_MULTIPLE_OBJECTIDS) {
 832                         btrfs_set_ref_objectid(leaf, ref,
 833                                         BTRFS_MULTIPLE_OBJECTIDS);
 834                 }
 835                 ret = 0;
 836         } else {
 837                 goto out;
 838         }
 839         btrfs_mark_buffer_dirty(path->nodes[0]);
 840 out:
 841         btrfs_release_path(root, path);
 842         return ret;
 843 }
 844
 845 static noinline int remove_extent_backref(struct btrfs_trans_handle *trans,
 846                                           struct btrfs_root *root,
 847                                           struct btrfs_path *path)
 848 {
 849         struct extent_buffer *leaf;
 850         struct btrfs_extent_ref *ref;
 851         u32 num_refs;
 852         int ret = 0;
 853
 854         leaf = path->nodes[0];
 855         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 856         num_refs = btrfs_ref_num_refs(leaf, ref);
 857         BUG_ON(num_refs == 0);
 858         num_refs -= 1;
 859         if (num_refs == 0) {
 860                 ret = btrfs_del_item(trans, root, path);
 861         } else {
 862                 btrfs_set_ref_num_refs(leaf, ref, num_refs);
 863                 btrfs_mark_buffer_dirty(leaf);
 864         }
 865         btrfs_release_path(root, path);
 866         return ret;
 867 }
 868
 869 #ifdef BIO_RW_DISCARD
 870 static void btrfs_issue_discard(struct block_device *bdev,
 871                                 u64 start, u64 len)
 872 {
 873         blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL);
 874 }
 875 #endif
 876
 877 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 878                                 u64 num_bytes)
 879 {
 880 #ifdef BIO_RW_DISCARD
 881         int ret;
 882         u64 map_length = num_bytes;
 883         struct btrfs_multi_bio *multi = NULL;
 884
 885         /* Tell the block device(s) that the sectors can be discarded */
 886         ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
 887                               bytenr, &map_length, &multi, 0);
 888         if (!ret) {
 889                 struct btrfs_bio_stripe *stripe = multi->stripes;
 890                 int i;
 891
 892                 if (map_length > num_bytes)
 893                         map_length = num_bytes;
 894
 895                 for (i = 0; i < multi->num_stripes; i++, stripe++) {
 896                         btrfs_issue_discard(stripe->dev->bdev,
 897                                             stripe->physical,
 898                                             map_length);
 899                 }
 900                 kfree(multi);
 901         }
 902
 903         return ret;
 904 #else
 905         return 0;
 906 #endif
 907 }
 908
 909 static noinline int free_extents(struct btrfs_trans_handle *trans,
 910                                  struct btrfs_root *extent_root,
 911                                  struct list_head *del_list)
 912 {
 913         struct btrfs_fs_info *info = extent_root->fs_info;
 914         struct btrfs_path *path;
 915         struct btrfs_key key, found_key;
 916         struct extent_buffer *leaf;
 917         struct list_head *cur;
 918         struct pending_extent_op *op;
 919         struct btrfs_extent_item *ei;
 920         int ret, num_to_del, extent_slot = 0, found_extent = 0;
 921         u32 refs;
 922         u64 bytes_freed = 0;
 923
 924         path = btrfs_alloc_path();
 925         if (!path)
 926                 return -ENOMEM;
 927         path->reada = 1;
 928
 929 search:
 930         /* search for the backref for the current ref we want to delete */
 931         cur = del_list->next;
 932         op = list_entry(cur, struct pending_extent_op, list);
 933         ret = lookup_extent_backref(trans, extent_root, path, op->bytenr,
 934                                     op->orig_parent,
 935                                     extent_root->root_key.objectid,
 936                                     op->orig_generation, op->level, 1);
 937         if (ret) {
 938                 printk(KERN_ERR "btrfs unable to find backref byte nr %llu "
 939                        "root %llu gen %llu owner %u\n",
 940                        (unsigned long long)op->bytenr,
 941                        (unsigned long long)extent_root->root_key.objectid,
 942                        (unsigned long long)op->orig_generation, op->level);
 943                 btrfs_print_leaf(extent_root, path->nodes[0]);
 944                 WARN_ON(1);
 945                 goto out;
 946         }
 947
 948         extent_slot = path->slots[0];
 949         num_to_del = 1;
 950         found_extent = 0;
 951
 952         /*
 953          * if we aren't the first item on the leaf we can move back one and see
 954          * if our ref is right next to our extent item
 955          */
 956         if (likely(extent_slot)) {
 957                 extent_slot--;
 958                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 959                                       extent_slot);
 960                 if (found_key.objectid == op->bytenr &&
 961                     found_key.type == BTRFS_EXTENT_ITEM_KEY &&
 962                     found_key.offset == op->num_bytes) {
 963                         num_to_del++;
 964                         found_extent = 1;
 965                 }
 966         }
 967
 968         /*
 969          * if we didn't find the extent we need to delete the backref and then
 970          * search for the extent item key so we can update its ref count
 971          */
 972         if (!found_extent) {
 973                 key.objectid = op->bytenr;
 974                 key.type = BTRFS_EXTENT_ITEM_KEY;
 975                 key.offset = op->num_bytes;
 976
 977                 ret = remove_extent_backref(trans, extent_root, path);
 978                 BUG_ON(ret);
 979                 btrfs_release_path(extent_root, path);
 980                 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
 981                 BUG_ON(ret);
 982                 extent_slot = path->slots[0];
 983         }
 984
 985         /* this is where we update the ref count for the extent */
 986         leaf = path->nodes[0];
 987         ei = btrfs_item_ptr(leaf, extent_slot, struct btrfs_extent_item);
 988         refs = btrfs_extent_refs(leaf, ei);
 989         BUG_ON(refs == 0);
 990         refs--;
 991         btrfs_set_extent_refs(leaf, ei, refs);
 992
 993         btrfs_mark_buffer_dirty(leaf);
 994
 995         /*
 996          * This extent needs deleting.  The reason cur_slot is extent_slot +
 997          * num_to_del is because extent_slot points to the slot where the extent
 998          * is, and if the backref was not right next to the extent we will be
 999          * deleting at least 1 item, and will want to start searching at the
1000          * slot directly next to extent_slot.  However if we did find the
1001          * backref next to the extent item them we will be deleting at least 2
1002          * items and will want to start searching directly after the ref slot
1003          */
1004         if (!refs) {
1005                 struct list_head *pos, *n, *end;
1006                 int cur_slot = extent_slot+num_to_del;
1007                 u64 super_used;
1008                 u64 root_used;
1009
1010                 path->slots[0] = extent_slot;
1011                 bytes_freed = op->num_bytes;
1012
1013                 mutex_lock(&info->pinned_mutex);
1014                 ret = pin_down_bytes(trans, extent_root, op->bytenr,
1015                                      op->num_bytes, op->level >=
1016                                      BTRFS_FIRST_FREE_OBJECTID);
1017                 mutex_unlock(&info->pinned_mutex);
1018                 BUG_ON(ret < 0);
1019                 op->del = ret;
1020
1021                 /*
1022                  * we need to see if we can delete multiple things at once, so
1023                  * start looping through the list of extents we are wanting to
1024                  * delete and see if their extent/backref's are right next to
1025                  * eachother and the extents only have 1 ref
1026                  */
1027                 for (pos = cur->next; pos != del_list; pos = pos->next) {
1028                         struct pending_extent_op *tmp;
1029
1030                         tmp = list_entry(pos, struct pending_extent_op, list);
1031
1032                         /* we only want to delete extent+ref at this stage */
1033                         if (cur_slot >= btrfs_header_nritems(leaf) - 1)
1034                                 break;
1035
1036                         btrfs_item_key_to_cpu(leaf, &found_key, cur_slot);
1037                         if (found_key.objectid != tmp->bytenr ||
1038                             found_key.type != BTRFS_EXTENT_ITEM_KEY ||
1039                             found_key.offset != tmp->num_bytes)
1040                                 break;
1041
1042                         /* check to make sure this extent only has one ref */
1043                         ei = btrfs_item_ptr(leaf, cur_slot,
1044                                             struct btrfs_extent_item);
1045                         if (btrfs_extent_refs(leaf, ei) != 1)
1046                                 break;
1047
1048                         btrfs_item_key_to_cpu(leaf, &found_key, cur_slot+1);
1049                         if (found_key.objectid != tmp->bytenr ||
1050                             found_key.type != BTRFS_EXTENT_REF_KEY ||
1051                             found_key.offset != tmp->orig_parent)
1052                                 break;
1053
1054                         /*
1055                          * the ref is right next to the extent, we can set the
1056                          * ref count to 0 since we will delete them both now
1057                          */
1058                         btrfs_set_extent_refs(leaf, ei, 0);
1059
1060                         /* pin down the bytes for this extent */
1061                         mutex_lock(&info->pinned_mutex);
1062                         ret = pin_down_bytes(trans, extent_root, tmp->bytenr,
1063                                              tmp->num_bytes, tmp->level >=
1064                                              BTRFS_FIRST_FREE_OBJECTID);
1065                         mutex_unlock(&info->pinned_mutex);
1066                         BUG_ON(ret < 0);
1067
1068                         /*
1069                          * use the del field to tell if we need to go ahead and
1070                          * free up the extent when we delete the item or not.
1071                          */
1072                         tmp->del = ret;
1073                         bytes_freed += tmp->num_bytes;
1074
1075                         num_to_del += 2;
1076                         cur_slot += 2;
1077                 }
1078                 end = pos;
1079
1080                 /* update the free space counters */
1081                 spin_lock(&info->delalloc_lock);
1082                 super_used = btrfs_super_bytes_used(&info->super_copy);
1083                 btrfs_set_super_bytes_used(&info->super_copy,
1084                                            super_used - bytes_freed);
1085
1086                 root_used = btrfs_root_used(&extent_root->root_item);
1087                 btrfs_set_root_used(&extent_root->root_item,
1088                                     root_used - bytes_freed);
1089                 spin_unlock(&info->delalloc_lock);
1090
1091                 /* delete the items */
1092                 ret = btrfs_del_items(trans, extent_root, path,
1093                                       path->slots[0], num_to_del);
1094                 BUG_ON(ret);
1095
1096                 /*
1097                  * loop through the extents we deleted and do the cleanup work
1098                  * on them
1099                  */
1100                 for (pos = cur, n = pos->next; pos != end;
1101                      pos = n, n = pos->next) {
1102                         struct pending_extent_op *tmp;
1103                         tmp = list_entry(pos, struct pending_extent_op, list);
1104
1105                         /*
1106                          * remember tmp->del tells us wether or not we pinned
1107                          * down the extent
1108                          */
1109                         ret = update_block_group(trans, extent_root,
1110                                                  tmp->bytenr, tmp->num_bytes, 0,
1111                                                  tmp->del);
1112                         BUG_ON(ret);
1113
1114                         list_del_init(&tmp->list);
1115                         unlock_extent(&info->extent_ins, tmp->bytenr,
1116                                       tmp->bytenr + tmp->num_bytes - 1,
1117                                       GFP_NOFS);
1118                         kfree(tmp);
1119                 }
1120         } else if (refs && found_extent) {
1121                 /*
1122                  * the ref and extent were right next to eachother, but the
1123                  * extent still has a ref, so just free the backref and keep
1124                  * going
1125                  */
1126                 ret = remove_extent_backref(trans, extent_root, path);
1127                 BUG_ON(ret);
1128
1129                 list_del_init(&op->list);
1130                 unlock_extent(&info->extent_ins, op->bytenr,
1131                               op->bytenr + op->num_bytes - 1, GFP_NOFS);
1132                 kfree(op);
1133         } else {
1134                 /*
1135                  * the extent has multiple refs and the backref we were looking
1136                  * for was not right next to it, so just unlock and go next,
1137                  * we're good to go
1138                  */
1139                 list_del_init(&op->list);
1140                 unlock_extent(&info->extent_ins, op->bytenr,
1141                               op->bytenr + op->num_bytes - 1, GFP_NOFS);
1142                 kfree(op);
1143         }
1144
1145         btrfs_release_path(extent_root, path);
1146         if (!list_empty(del_list))
1147                 goto search;
1148
1149 out:
1150         btrfs_free_path(path);
1151         return ret;
1152 }
1153
1154 static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
1155                                      struct btrfs_root *root, u64 bytenr,
1156                                      u64 orig_parent, u64 parent,
1157                                      u64 orig_root, u64 ref_root,
1158                                      u64 orig_generation, u64 ref_generation,
1159                                      u64 owner_objectid)
1160 {
1161         int ret;
1162         struct btrfs_root *extent_root = root->fs_info->extent_root;
1163         struct btrfs_path *path;
1164
1165         if (root == root->fs_info->extent_root) {
1166                 struct pending_extent_op *extent_op;
1167                 u64 num_bytes;
1168
1169                 BUG_ON(owner_objectid >= BTRFS_MAX_LEVEL);
1170                 num_bytes = btrfs_level_size(root, (int)owner_objectid);
1171                 mutex_lock(&root->fs_info->extent_ins_mutex);
1172                 if (test_range_bit(&root->fs_info->extent_ins, bytenr,
1173                                 bytenr + num_bytes - 1, EXTENT_WRITEBACK, 0)) {
1174                         u64 priv;
1175                         ret = get_state_private(&root->fs_info->extent_ins,
1176                                                 bytenr, &priv);
1177                         BUG_ON(ret);
1178                         extent_op = (struct pending_extent_op *)
1179                                                         (unsigned long)priv;
1180                         BUG_ON(extent_op->parent != orig_parent);
1181                         BUG_ON(extent_op->generation != orig_generation);
1182
1183                         extent_op->parent = parent;
1184                         extent_op->generation = ref_generation;
1185                 } else {
1186                         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
1187                         BUG_ON(!extent_op);
1188
1189                         extent_op->type = PENDING_BACKREF_UPDATE;
1190                         extent_op->bytenr = bytenr;
1191                         extent_op->num_bytes = num_bytes;
1192                         extent_op->parent = parent;
1193                         extent_op->orig_parent = orig_parent;
1194                         extent_op->generation = ref_generation;
1195                         extent_op->orig_generation = orig_generation;
1196                         extent_op->level = (int)owner_objectid;
1197                         INIT_LIST_HEAD(&extent_op->list);
1198                         extent_op->del = 0;
1199
1200                         set_extent_bits(&root->fs_info->extent_ins,
1201                                         bytenr, bytenr + num_bytes - 1,
1202                                         EXTENT_WRITEBACK, GFP_NOFS);
1203                         set_state_private(&root->fs_info->extent_ins,
1204                                           bytenr, (unsigned long)extent_op);
1205                 }
1206                 mutex_unlock(&root->fs_info->extent_ins_mutex);
1207                 return 0;
1208         }
1209
1210         path = btrfs_alloc_path();
1211         if (!path)
1212                 return -ENOMEM;
1213         ret = lookup_extent_backref(trans, extent_root, path,
1214                                     bytenr, orig_parent, orig_root,
1215                                     orig_generation, owner_objectid, 1);
1216         if (ret)
1217                 goto out;
1218         ret = remove_extent_backref(trans, extent_root, path);
1219         if (ret)
1220                 goto out;
1221         ret = insert_extent_backref(trans, extent_root, path, bytenr,
1222                                     parent, ref_root, ref_generation,
1223                                     owner_objectid);
1224         BUG_ON(ret);
1225         finish_current_insert(trans, extent_root, 0);
1226         del_pending_extents(trans, extent_root, 0);
1227 out:
1228         btrfs_free_path(path);
1229         return ret;
1230 }
1231
1232 int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
1233                             struct btrfs_root *root, u64 bytenr,
1234                             u64 orig_parent, u64 parent,
1235                             u64 ref_root, u64 ref_generation,
1236                             u64 owner_objectid)
1237 {
1238         int ret;
1239         if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
1240             owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
1241                 return 0;
1242         ret = __btrfs_update_extent_ref(trans, root, bytenr, orig_parent,
1243                                         parent, ref_root, ref_root,
1244                                         ref_generation, ref_generation,
1245                                         owner_objectid);
1246         return ret;
1247 }
1248
1249 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1250                                   struct btrfs_root *root, u64 bytenr,
1251                                   u64 orig_parent, u64 parent,
1252                                   u64 orig_root, u64 ref_root,
1253                                   u64 orig_generation, u64 ref_generation,
1254                                   u64 owner_objectid)
1255 {
1256         struct btrfs_path *path;
1257         int ret;
1258         struct btrfs_key key;
1259         struct extent_buffer *l;
1260         struct btrfs_extent_item *item;
1261         u32 refs;
1262
1263         path = btrfs_alloc_path();
1264         if (!path)
1265                 return -ENOMEM;
1266
1267         path->reada = 1;
1268         key.objectid = bytenr;
1269         key.type = BTRFS_EXTENT_ITEM_KEY;
1270         key.offset = (u64)-1;
1271
1272         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
1273                                 0, 1);
1274         if (ret < 0)
1275                 return ret;
1276         BUG_ON(ret == 0 || path->slots[0] == 0);
1277
1278         path->slots[0]--;
1279         l = path->nodes[0];
1280
1281         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1282         if (key.objectid != bytenr) {
1283                 btrfs_print_leaf(root->fs_info->extent_root, path->nodes[0]);
1284                 printk(KERN_ERR "btrfs wanted %llu found %llu\n",
1285                        (unsigned long long)bytenr,
1286                        (unsigned long long)key.objectid);
1287                 BUG();
1288         }
1289         BUG_ON(key.type != BTRFS_EXTENT_ITEM_KEY);
1290
1291         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
1292         refs = btrfs_extent_refs(l, item);
1293         btrfs_set_extent_refs(l, item, refs + 1);
1294         btrfs_mark_buffer_dirty(path->nodes[0]);
1295
1296         btrfs_release_path(root->fs_info->extent_root, path);
1297
1298         path->reada = 1;
1299         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1300                                     path, bytenr, parent,
1301                                     ref_root, ref_generation,
1302                                     owner_objectid);
1303         BUG_ON(ret);
1304         finish_current_insert(trans, root->fs_info->extent_root, 0);
1305         del_pending_extents(trans, root->fs_info->extent_root, 0);
1306
1307         btrfs_free_path(path);
1308         return 0;
1309 }
1310
1311 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1312                          struct btrfs_root *root,
1313                          u64 bytenr, u64 num_bytes, u64 parent,
1314                          u64 ref_root, u64 ref_generation,
1315                          u64 owner_objectid)
1316 {
1317         int ret;
1318         if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
1319             owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
1320                 return 0;
1321         ret = __btrfs_inc_extent_ref(trans, root, bytenr, 0, parent,
1322                                      0, ref_root, 0, ref_generation,
1323                                      owner_objectid);
1324         return ret;
1325 }
1326
1327 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
1328                          struct btrfs_root *root)
1329 {
1330         u64 start;
1331         u64 end;
1332         int ret;
1333
1334         while(1) {
1335                 finish_current_insert(trans, root->fs_info->extent_root, 1);
1336                 del_pending_extents(trans, root->fs_info->extent_root, 1);
1337
1338                 /* is there more work to do? */
1339                 ret = find_first_extent_bit(&root->fs_info->pending_del,
1340                                             0, &start, &end, EXTENT_WRITEBACK);
1341                 if (!ret)
1342                         continue;
1343                 ret = find_first_extent_bit(&root->fs_info->extent_ins,
1344                                             0, &start, &end, EXTENT_WRITEBACK);
1345                 if (!ret)
1346                         continue;
1347                 break;
1348         }
1349         return 0;
1350 }
1351
1352 int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans,
1353                             struct btrfs_root *root, u64 bytenr,
1354                             u64 num_bytes, u32 *refs)
1355 {
1356         struct btrfs_path *path;
1357         int ret;
1358         struct btrfs_key key;
1359         struct extent_buffer *l;
1360         struct btrfs_extent_item *item;
1361
1362         WARN_ON(num_bytes < root->sectorsize);
1363         path = btrfs_alloc_path();
1364         path->reada = 1;
1365         key.objectid = bytenr;
1366         key.offset = num_bytes;
1367         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1368         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
1369                                 0, 0);
1370         if (ret < 0)
1371                 goto out;
1372         if (ret != 0) {
1373                 btrfs_print_leaf(root, path->nodes[0]);
1374                 printk(KERN_INFO "btrfs failed to find block number %llu\n",
1375                        (unsigned long long)bytenr);
1376                 BUG();
1377         }
1378         l = path->nodes[0];
1379         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
1380         *refs = btrfs_extent_refs(l, item);
1381 out:
1382         btrfs_free_path(path);
1383         return 0;
1384 }
1385
1386 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
1387                           struct btrfs_root *root, u64 objectid, u64 bytenr)
1388 {
1389         struct btrfs_root *extent_root = root->fs_info->extent_root;
1390         struct btrfs_path *path;
1391         struct extent_buffer *leaf;
1392         struct btrfs_extent_ref *ref_item;
1393         struct btrfs_key key;
1394         struct btrfs_key found_key;
1395         u64 ref_root;
1396         u64 last_snapshot;
1397         u32 nritems;
1398         int ret;
1399
1400         key.objectid = bytenr;
1401         key.offset = (u64)-1;
1402         key.type = BTRFS_EXTENT_ITEM_KEY;
1403
1404         path = btrfs_alloc_path();
1405         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
1406         if (ret < 0)
1407                 goto out;
1408         BUG_ON(ret == 0);
1409
1410         ret = -ENOENT;
1411         if (path->slots[0] == 0)
1412                 goto out;
1413
1414         path->slots[0]--;
1415         leaf = path->nodes[0];
1416         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1417
1418         if (found_key.objectid != bytenr ||
1419             found_key.type != BTRFS_EXTENT_ITEM_KEY)
1420                 goto out;
1421
1422         last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1423         while (1) {
1424                 leaf = path->nodes[0];
1425                 nritems = btrfs_header_nritems(leaf);
1426                 if (path->slots[0] >= nritems) {
1427                         ret = btrfs_next_leaf(extent_root, path);
1428                         if (ret < 0)
1429                                 goto out;
1430                         if (ret == 0)
1431                                 continue;
1432                         break;
1433                 }
1434                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1435                 if (found_key.objectid != bytenr)
1436                         break;
1437
1438                 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
1439                         path->slots[0]++;
1440                         continue;
1441                 }
1442
1443                 ref_item = btrfs_item_ptr(leaf, path->slots[0],
1444                                           struct btrfs_extent_ref);
1445                 ref_root = btrfs_ref_root(leaf, ref_item);
1446                 if ((ref_root != root->root_key.objectid &&
1447                      ref_root != BTRFS_TREE_LOG_OBJECTID) ||
1448                      objectid != btrfs_ref_objectid(leaf, ref_item)) {
1449                         ret = 1;
1450                         goto out;
1451                 }
1452                 if (btrfs_ref_generation(leaf, ref_item) <= last_snapshot) {
1453                         ret = 1;
1454                         goto out;
1455                 }
1456
1457                 path->slots[0]++;
1458         }
1459         ret = 0;
1460 out:
1461         btrfs_free_path(path);
1462         return ret;
1463 }
1464
1465 int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1466                     struct extent_buffer *buf, u32 nr_extents)
1467 {
1468         struct btrfs_key key;
1469         struct btrfs_file_extent_item *fi;
1470         u64 root_gen;
1471         u32 nritems;
1472         int i;
1473         int level;
1474         int ret = 0;
1475         int shared = 0;
1476
1477         if (!root->ref_cows)
1478                 return 0;
1479
1480         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1481                 shared = 0;
1482                 root_gen = root->root_key.offset;
1483         } else {
1484                 shared = 1;
1485                 root_gen = trans->transid - 1;
1486         }
1487
1488         level = btrfs_header_level(buf);
1489         nritems = btrfs_header_nritems(buf);
1490
1491         if (level == 0) {
1492                 struct btrfs_leaf_ref *ref;
1493                 struct btrfs_extent_info *info;
1494
1495                 ref = btrfs_alloc_leaf_ref(root, nr_extents);
1496                 if (!ref) {
1497                         ret = -ENOMEM;
1498                         goto out;
1499                 }
1500
1501                 ref->root_gen = root_gen;
1502                 ref->bytenr = buf->start;
1503                 ref->owner = btrfs_header_owner(buf);
1504                 ref->generation = btrfs_header_generation(buf);
1505                 ref->nritems = nr_extents;
1506                 info = ref->extents;
1507
1508                 for (i = 0; nr_extents > 0 && i < nritems; i++) {
1509                         u64 disk_bytenr;
1510                         btrfs_item_key_to_cpu(buf, &key, i);
1511                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1512                                 continue;
1513                         fi = btrfs_item_ptr(buf, i,
1514                                             struct btrfs_file_extent_item);
1515                         if (btrfs_file_extent_type(buf, fi) ==
1516                             BTRFS_FILE_EXTENT_INLINE)
1517                                 continue;
1518                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1519                         if (disk_bytenr == 0)
1520                                 continue;
1521
1522                         info->bytenr = disk_bytenr;
1523                         info->num_bytes =
1524                                 btrfs_file_extent_disk_num_bytes(buf, fi);
1525                         info->objectid = key.objectid;
1526                         info->offset = key.offset;
1527                         info++;
1528                 }
1529
1530                 ret = btrfs_add_leaf_ref(root, ref, shared);
1531                 if (ret == -EEXIST && shared) {
1532                         struct btrfs_leaf_ref *old;
1533                         old = btrfs_lookup_leaf_ref(root, ref->bytenr);
1534                         BUG_ON(!old);
1535                         btrfs_remove_leaf_ref(root, old);
1536                         btrfs_free_leaf_ref(root, old);
1537                         ret = btrfs_add_leaf_ref(root, ref, shared);
1538                 }
1539                 WARN_ON(ret);
1540                 btrfs_free_leaf_ref(root, ref);
1541         }
1542 out:
1543         return ret;
1544 }
1545
1546 /* when a block goes through cow, we update the reference counts of
1547  * everything that block points to.  The internal pointers of the block
1548  * can be in just about any order, and it is likely to have clusters of
1549  * things that are close together and clusters of things that are not.
1550  *
1551  * To help reduce the seeks that come with updating all of these reference
1552  * counts, sort them by byte number before actual updates are done.
1553  *
1554  * struct refsort is used to match byte number to slot in the btree block.
1555  * we sort based on the byte number and then use the slot to actually
1556  * find the item.
1557  *
1558  * struct refsort is smaller than strcut btrfs_item and smaller than
1559  * struct btrfs_key_ptr.  Since we're currently limited to the page size
1560  * for a btree block, there's no way for a kmalloc of refsorts for a
1561  * single node to be bigger than a page.
1562  */
1563 struct refsort {
1564         u64 bytenr;
1565         u32 slot;
1566 };
1567
1568 /*
1569  * for passing into sort()
1570  */
1571 static int refsort_cmp(const void *a_void, const void *b_void)
1572 {
1573         const struct refsort *a = a_void;
1574         const struct refsort *b = b_void;
1575
1576         if (a->bytenr < b->bytenr)
1577                 return -1;
1578         if (a->bytenr > b->bytenr)
1579                 return 1;
1580         return 0;
1581 }
1582
1583
1584 noinline int btrfs_inc_ref(struct btrfs_trans_handle *trans,
1585                            struct btrfs_root *root,
1586                            struct extent_buffer *orig_buf,
1587                            struct extent_buffer *buf, u32 *nr_extents)
1588 {
1589         u64 bytenr;
1590         u64 ref_root;
1591         u64 orig_root;
1592         u64 ref_generation;
1593         u64 orig_generation;
1594         struct refsort *sorted;
1595         u32 nritems;
1596         u32 nr_file_extents = 0;
1597         struct btrfs_key key;
1598         struct btrfs_file_extent_item *fi;
1599         int i;
1600         int level;
1601         int ret = 0;
1602         int faili = 0;
1603         int refi = 0;
1604         int slot;
1605         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
1606                             u64, u64, u64, u64, u64, u64, u64, u64);
1607
1608         ref_root = btrfs_header_owner(buf);
1609         ref_generation = btrfs_header_generation(buf);
1610         orig_root = btrfs_header_owner(orig_buf);
1611         orig_generation = btrfs_header_generation(orig_buf);
1612
1613         nritems = btrfs_header_nritems(buf);
1614         level = btrfs_header_level(buf);
1615
1616         sorted = kmalloc(sizeof(struct refsort) * nritems, GFP_NOFS);
1617         BUG_ON(!sorted);
1618
1619         if (root->ref_cows) {
1620                 process_func = __btrfs_inc_extent_ref;
1621         } else {
1622                 if (level == 0 &&
1623                     root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
1624                         goto out;
1625                 if (level != 0 &&
1626                     root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID)
1627                         goto out;
1628                 process_func = __btrfs_update_extent_ref;
1629         }
1630
1631         /*
1632          * we make two passes through the items.  In the first pass we
1633          * only record the byte number and slot.  Then we sort based on
1634          * byte number and do the actual work based on the sorted results
1635          */
1636         for (i = 0; i < nritems; i++) {
1637                 cond_resched();
1638                 if (level == 0) {
1639                         btrfs_item_key_to_cpu(buf, &key, i);
1640                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1641                                 continue;
1642                         fi = btrfs_item_ptr(buf, i,
1643                                             struct btrfs_file_extent_item);
1644                         if (btrfs_file_extent_type(buf, fi) ==
1645                             BTRFS_FILE_EXTENT_INLINE)
1646                                 continue;
1647                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1648                         if (bytenr == 0)
1649                                 continue;
1650
1651                         nr_file_extents++;
1652                         sorted[refi].bytenr = bytenr;
1653                         sorted[refi].slot = i;
1654                         refi++;
1655                 } else {
1656                         bytenr = btrfs_node_blockptr(buf, i);
1657                         sorted[refi].bytenr = bytenr;
1658                         sorted[refi].slot = i;
1659                         refi++;
1660                 }
1661         }
1662         /*
1663          * if refi == 0, we didn't actually put anything into the sorted
1664          * array and we're done
1665          */
1666         if (refi == 0)
1667                 goto out;
1668
1669         sort(sorted, refi, sizeof(struct refsort), refsort_cmp, NULL);
1670
1671         for (i = 0; i < refi; i++) {
1672                 cond_resched();
1673                 slot = sorted[i].slot;
1674                 bytenr = sorted[i].bytenr;
1675
1676                 if (level == 0) {
1677                         btrfs_item_key_to_cpu(buf, &key, slot);
1678
1679                         ret = process_func(trans, root, bytenr,
1680                                            orig_buf->start, buf->start,
1681                                            orig_root, ref_root,
1682                                            orig_generation, ref_generation,
1683                                            key.objectid);
1684
1685                         if (ret) {
1686                                 faili = slot;
1687                                 WARN_ON(1);
1688                                 goto fail;
1689                         }
1690                 } else {
1691                         ret = process_func(trans, root, bytenr,
1692                                            orig_buf->start, buf->start,
1693                                            orig_root, ref_root,
1694                                            orig_generation, ref_generation,
1695                                            level - 1);
1696                         if (ret) {
1697                                 faili = slot;
1698                                 WARN_ON(1);
1699                                 goto fail;
1700                         }
1701                 }
1702         }
1703 out:
1704         kfree(sorted);
1705         if (nr_extents) {
1706                 if (level == 0)
1707                         *nr_extents = nr_file_extents;
1708                 else
1709                         *nr_extents = nritems;
1710         }
1711         return 0;
1712 fail:
1713         kfree(sorted);
1714         WARN_ON(1);
1715         return ret;
1716 }
1717
1718 int btrfs_update_ref(struct btrfs_trans_handle *trans,
1719                      struct btrfs_root *root, struct extent_buffer *orig_buf,
1720                      struct extent_buffer *buf, int start_slot, int nr)
1721
1722 {
1723         u64 bytenr;
1724         u64 ref_root;
1725         u64 orig_root;
1726         u64 ref_generation;
1727         u64 orig_generation;
1728         struct btrfs_key key;
1729         struct btrfs_file_extent_item *fi;
1730         int i;
1731         int ret;
1732         int slot;
1733         int level;
1734
1735         BUG_ON(start_slot < 0);
1736         BUG_ON(start_slot + nr > btrfs_header_nritems(buf));
1737
1738         ref_root = btrfs_header_owner(buf);
1739         ref_generation = btrfs_header_generation(buf);
1740         orig_root = btrfs_header_owner(orig_buf);
1741         orig_generation = btrfs_header_generation(orig_buf);
1742         level = btrfs_header_level(buf);
1743
1744         if (!root->ref_cows) {
1745                 if (level == 0 &&
1746                     root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
1747                         return 0;
1748                 if (level != 0 &&
1749                     root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID)
1750                         return 0;
1751         }
1752
1753         for (i = 0, slot = start_slot; i < nr; i++, slot++) {
1754                 cond_resched();
1755                 if (level == 0) {
1756                         btrfs_item_key_to_cpu(buf, &key, slot);
1757                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1758                                 continue;
1759                         fi = btrfs_item_ptr(buf, slot,
1760                                             struct btrfs_file_extent_item);
1761                         if (btrfs_file_extent_type(buf, fi) ==
1762                             BTRFS_FILE_EXTENT_INLINE)
1763                                 continue;
1764                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1765                         if (bytenr == 0)
1766                                 continue;
1767                         ret = __btrfs_update_extent_ref(trans, root, bytenr,
1768                                             orig_buf->start, buf->start,
1769                                             orig_root, ref_root,
1770                                             orig_generation, ref_generation,
1771                                             key.objectid);
1772                         if (ret)
1773                                 goto fail;
1774                 } else {
1775                         bytenr = btrfs_node_blockptr(buf, slot);
1776                         ret = __btrfs_update_extent_ref(trans, root, bytenr,
1777                                             orig_buf->start, buf->start,
1778                                             orig_root, ref_root,
1779                                             orig_generation, ref_generation,
1780                                             level - 1);
1781                         if (ret)
1782                                 goto fail;
1783                 }
1784         }
1785         return 0;
1786 fail:
1787         WARN_ON(1);
1788         return -1;
1789 }
1790
1791 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1792                                  struct btrfs_root *root,
1793                                  struct btrfs_path *path,
1794                                  struct btrfs_block_group_cache *cache)
1795 {
1796         int ret;
1797         int pending_ret;
1798         struct btrfs_root *extent_root = root->fs_info->extent_root;
1799         unsigned long bi;
1800         struct extent_buffer *leaf;
1801
1802         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1803         if (ret < 0)
1804                 goto fail;
1805         BUG_ON(ret);
1806
1807         leaf = path->nodes[0];
1808         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1809         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1810         btrfs_mark_buffer_dirty(leaf);
1811         btrfs_release_path(extent_root, path);
1812 fail:
1813         finish_current_insert(trans, extent_root, 0);
1814         pending_ret = del_pending_extents(trans, extent_root, 0);
1815         if (ret)
1816                 return ret;
1817         if (pending_ret)
1818                 return pending_ret;
1819         return 0;
1820
1821 }
1822
1823 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1824                                    struct btrfs_root *root)
1825 {
1826         struct btrfs_block_group_cache *cache, *entry;
1827         struct rb_node *n;
1828         int err = 0;
1829         int werr = 0;
1830         struct btrfs_path *path;
1831         u64 last = 0;
1832
1833         path = btrfs_alloc_path();
1834         if (!path)
1835                 return -ENOMEM;
1836
1837         while (1) {
1838                 cache = NULL;
1839                 spin_lock(&root->fs_info->block_group_cache_lock);
1840                 for (n = rb_first(&root->fs_info->block_group_cache_tree);
1841                      n; n = rb_next(n)) {
1842                         entry = rb_entry(n, struct btrfs_block_group_cache,
1843                                          cache_node);
1844                         if (entry->dirty) {
1845                                 cache = entry;
1846                                 break;
1847                         }
1848                 }
1849                 spin_unlock(&root->fs_info->block_group_cache_lock);
1850
1851                 if (!cache)
1852                         break;
1853
1854                 cache->dirty = 0;
1855                 last += cache->key.offset;
1856
1857                 err = write_one_cache_group(trans, root,
1858                                             path, cache);
1859                 /*
1860                  * if we fail to write the cache group, we want
1861                  * to keep it marked dirty in hopes that a later
1862                  * write will work
1863                  */
1864                 if (err) {
1865                         werr = err;
1866                         continue;
1867                 }
1868         }
1869         btrfs_free_path(path);
1870         return werr;
1871 }
1872
1873 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
1874 {
1875         struct btrfs_block_group_cache *block_group;
1876         int readonly = 0;
1877
1878         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
1879         if (!block_group || block_group->ro)
1880                 readonly = 1;
1881         if (block_group)
1882                 put_block_group(block_group);
1883         return readonly;
1884 }
1885
1886 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1887                              u64 total_bytes, u64 bytes_used,
1888                              struct btrfs_space_info **space_info)
1889 {
1890         struct btrfs_space_info *found;
1891
1892         found = __find_space_info(info, flags);
1893         if (found) {
1894                 spin_lock(&found->lock);
1895                 found->total_bytes += total_bytes;
1896                 found->bytes_used += bytes_used;
1897                 found->full = 0;
1898                 spin_unlock(&found->lock);
1899                 *space_info = found;
1900                 return 0;
1901         }
1902         found = kzalloc(sizeof(*found), GFP_NOFS);
1903         if (!found)
1904                 return -ENOMEM;
1905
1906         list_add(&found->list, &info->space_info);
1907         INIT_LIST_HEAD(&found->block_groups);
1908         init_rwsem(&found->groups_sem);
1909         spin_lock_init(&found->lock);
1910         found->flags = flags;
1911         found->total_bytes = total_bytes;
1912         found->bytes_used = bytes_used;
1913         found->bytes_pinned = 0;
1914         found->bytes_reserved = 0;
1915         found->bytes_readonly = 0;
1916         found->bytes_delalloc = 0;
1917         found->full = 0;
1918         found->force_alloc = 0;
1919         *space_info = found;
1920         return 0;
1921 }
1922
1923 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1924 {
1925         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1926                                    BTRFS_BLOCK_GROUP_RAID1 |
1927                                    BTRFS_BLOCK_GROUP_RAID10 |
1928                                    BTRFS_BLOCK_GROUP_DUP);
1929         if (extra_flags) {
1930                 if (flags & BTRFS_BLOCK_GROUP_DATA)
1931                         fs_info->avail_data_alloc_bits |= extra_flags;
1932                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1933                         fs_info->avail_metadata_alloc_bits |= extra_flags;
1934                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1935                         fs_info->avail_system_alloc_bits |= extra_flags;
1936         }
1937 }
1938
1939 static void set_block_group_readonly(struct btrfs_block_group_cache *cache)
1940 {
1941         spin_lock(&cache->space_info->lock);
1942         spin_lock(&cache->lock);
1943         if (!cache->ro) {
1944                 cache->space_info->bytes_readonly += cache->key.offset -
1945                                         btrfs_block_group_used(&cache->item);
1946                 cache->ro = 1;
1947         }
1948         spin_unlock(&cache->lock);
1949         spin_unlock(&cache->space_info->lock);
1950 }
1951
1952 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
1953 {
1954         u64 num_devices = root->fs_info->fs_devices->rw_devices;
1955
1956         if (num_devices == 1)
1957                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
1958         if (num_devices < 4)
1959                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
1960
1961         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
1962             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
1963                       BTRFS_BLOCK_GROUP_RAID10))) {
1964                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
1965         }
1966
1967         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
1968             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
1969                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
1970         }
1971
1972         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
1973             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
1974              (flags & BTRFS_BLOCK_GROUP_RAID10) |
1975              (flags & BTRFS_BLOCK_GROUP_DUP)))
1976                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
1977         return flags;
1978 }
1979
1980 static u64 btrfs_get_alloc_profile(struct btrfs_root *root, u64 data)
1981 {
1982         struct btrfs_fs_info *info = root->fs_info;
1983         u64 alloc_profile;
1984
1985         if (data) {
1986                 alloc_profile = info->avail_data_alloc_bits &
1987                         info->data_alloc_profile;
1988                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
1989         } else if (root == root->fs_info->chunk_root) {
1990                 alloc_profile = info->avail_system_alloc_bits &
1991                         info->system_alloc_profile;
1992                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
1993         } else {
1994                 alloc_profile = info->avail_metadata_alloc_bits &
1995                         info->metadata_alloc_profile;
1996                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
1997         }
1998
1999         return btrfs_reduce_alloc_profile(root, data);
2000 }
2001
2002 void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *inode)
2003 {
2004         u64 alloc_target;
2005
2006         alloc_target = btrfs_get_alloc_profile(root, 1);
2007         BTRFS_I(inode)->space_info = __find_space_info(root->fs_info,
2008                                                        alloc_target);
2009 }
2010
2011 /*
2012  * for now this just makes sure we have at least 5% of our metadata space free
2013  * for use.
2014  */
2015 int btrfs_check_metadata_free_space(struct btrfs_root *root)
2016 {
2017         struct btrfs_fs_info *info = root->fs_info;
2018         struct btrfs_space_info *meta_sinfo;
2019         u64 alloc_target, thresh;
2020         int committed = 0, ret;
2021
2022         /* get the space info for where the metadata will live */
2023         alloc_target = btrfs_get_alloc_profile(root, 0);
2024         meta_sinfo = __find_space_info(info, alloc_target);
2025
2026 again:
2027         spin_lock(&meta_sinfo->lock);
2028         if (!meta_sinfo->full)
2029                 thresh = meta_sinfo->total_bytes * 80;
2030         else
2031                 thresh = meta_sinfo->total_bytes * 95;
2032
2033         do_div(thresh, 100);
2034
2035         if (meta_sinfo->bytes_used + meta_sinfo->bytes_reserved +
2036             meta_sinfo->bytes_pinned + meta_sinfo->bytes_readonly > thresh) {
2037                 struct btrfs_trans_handle *trans;
2038                 if (!meta_sinfo->full) {
2039                         meta_sinfo->force_alloc = 1;
2040                         spin_unlock(&meta_sinfo->lock);
2041
2042                         trans = btrfs_start_transaction(root, 1);
2043                         if (!trans)
2044                                 return -ENOMEM;
2045
2046                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2047                                              2 * 1024 * 1024, alloc_target, 0);
2048                         btrfs_end_transaction(trans, root);
2049                         goto again;
2050                 }
2051                 spin_unlock(&meta_sinfo->lock);
2052
2053                 if (!committed) {
2054                         committed = 1;
2055                         trans = btrfs_join_transaction(root, 1);
2056                         if (!trans)
2057                                 return -ENOMEM;
2058                         ret = btrfs_commit_transaction(trans, root);
2059                         if (ret)
2060                                 return ret;
2061                         goto again;
2062                 }
2063                 return -ENOSPC;
2064         }
2065         spin_unlock(&meta_sinfo->lock);
2066
2067         return 0;
2068 }
2069
2070 /*
2071  * This will check the space that the inode allocates from to make sure we have
2072  * enough space for bytes.
2073  */
2074 int btrfs_check_data_free_space(struct btrfs_root *root, struct inode *inode,
2075                                 u64 bytes)
2076 {
2077         struct btrfs_space_info *data_sinfo;
2078         int ret = 0, committed = 0;
2079
2080         /* make sure bytes are sectorsize aligned */
2081         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
2082
2083         data_sinfo = BTRFS_I(inode)->space_info;
2084 again:
2085         /* make sure we have enough space to handle the data first */
2086         spin_lock(&data_sinfo->lock);
2087         if (data_sinfo->total_bytes - data_sinfo->bytes_used -
2088             data_sinfo->bytes_delalloc - data_sinfo->bytes_reserved -
2089             data_sinfo->bytes_pinned - data_sinfo->bytes_readonly -
2090             data_sinfo->bytes_may_use < bytes) {
2091                 struct btrfs_trans_handle *trans;
2092
2093                 /*
2094                  * if we don't have enough free bytes in this space then we need
2095                  * to alloc a new chunk.
2096                  */
2097                 if (!data_sinfo->full) {
2098                         u64 alloc_target;
2099
2100                         data_sinfo->force_alloc = 1;
2101                         spin_unlock(&data_sinfo->lock);
2102
2103                         alloc_target = btrfs_get_alloc_profile(root, 1);
2104                         trans = btrfs_start_transaction(root, 1);
2105                         if (!trans)
2106                                 return -ENOMEM;
2107
2108                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
2109                                              bytes + 2 * 1024 * 1024,
2110                                              alloc_target, 0);
2111                         btrfs_end_transaction(trans, root);
2112                         if (ret)
2113                                 return ret;
2114                         goto again;
2115                 }
2116                 spin_unlock(&data_sinfo->lock);
2117
2118                 /* commit the current transaction and try again */
2119                 if (!committed) {
2120                         committed = 1;
2121                         trans = btrfs_join_transaction(root, 1);
2122                         if (!trans)
2123                                 return -ENOMEM;
2124                         ret = btrfs_commit_transaction(trans, root);
2125                         if (ret)
2126                                 return ret;
2127                         goto again;
2128                 }
2129
2130                 printk(KERN_ERR "no space left, need %llu, %llu delalloc bytes"
2131                        ", %llu bytes_used, %llu bytes_reserved, "
2132                        "%llu bytes_pinned, %llu bytes_readonly, %llu may use"
2133                        "%llu total\n", bytes, data_sinfo->bytes_delalloc,
2134                        data_sinfo->bytes_used, data_sinfo->bytes_reserved,
2135                        data_sinfo->bytes_pinned, data_sinfo->bytes_readonly,
2136                        data_sinfo->bytes_may_use, data_sinfo->total_bytes);
2137                 return -ENOSPC;
2138         }
2139         data_sinfo->bytes_may_use += bytes;
2140         BTRFS_I(inode)->reserved_bytes += bytes;
2141         spin_unlock(&data_sinfo->lock);
2142
2143         return btrfs_check_metadata_free_space(root);
2144 }
2145
2146 /*
2147  * if there was an error for whatever reason after calling
2148  * btrfs_check_data_free_space, call this so we can cleanup the counters.
2149  */
2150 void btrfs_free_reserved_data_space(struct btrfs_root *root,
2151                                     struct inode *inode, u64 bytes)
2152 {
2153         struct btrfs_space_info *data_sinfo;
2154
2155         /* make sure bytes are sectorsize aligned */
2156         bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
2157
2158         data_sinfo = BTRFS_I(inode)->space_info;
2159         spin_lock(&data_sinfo->lock);
2160         data_sinfo->bytes_may_use -= bytes;
2161         BTRFS_I(inode)->reserved_bytes -= bytes;
2162         spin_unlock(&data_sinfo->lock);
2163 }
2164
2165 /* called when we are adding a delalloc extent to the inode's io_tree */
2166 void btrfs_delalloc_reserve_space(struct btrfs_root *root, struct inode *inode,
2167                                   u64 bytes)
2168 {
2169         struct btrfs_space_info *data_sinfo;
2170
2171         /* get the space info for where this inode will be storing its data */
2172         data_sinfo = BTRFS_I(inode)->space_info;
2173
2174         /* make sure we have enough space to handle the data first */
2175         spin_lock(&data_sinfo->lock);
2176         data_sinfo->bytes_delalloc += bytes;
2177
2178         /*
2179          * we are adding a delalloc extent without calling
2180          * btrfs_check_data_free_space first.  This happens on a weird
2181          * writepage condition, but shouldn't hurt our accounting
2182          */
2183         if (unlikely(bytes > BTRFS_I(inode)->reserved_bytes)) {
2184                 data_sinfo->bytes_may_use -= BTRFS_I(inode)->reserved_bytes;
2185                 BTRFS_I(inode)->reserved_bytes = 0;
2186         } else {
2187                 data_sinfo->bytes_may_use -= bytes;
2188                 BTRFS_I(inode)->reserved_bytes -= bytes;
2189         }
2190
2191         spin_unlock(&data_sinfo->lock);
2192 }
2193
2194 /* called when we are clearing an delalloc extent from the inode's io_tree */
2195 void btrfs_delalloc_free_space(struct btrfs_root *root, struct inode *inode,
2196                               u64 bytes)
2197 {
2198         struct btrfs_space_info *info;
2199
2200         info = BTRFS_I(inode)->space_info;
2201
2202         spin_lock(&info->lock);
2203         info->bytes_delalloc -= bytes;
2204         spin_unlock(&info->lock);
2205 }
2206
2207 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
2208                           struct btrfs_root *extent_root, u64 alloc_bytes,
2209                           u64 flags, int force)
2210 {
2211         struct btrfs_space_info *space_info;
2212         u64 thresh;
2213         int ret = 0;
2214
2215         mutex_lock(&extent_root->fs_info->chunk_mutex);
2216
2217         flags = btrfs_reduce_alloc_profile(extent_root, flags);
2218
2219         space_info = __find_space_info(extent_root->fs_info, flags);
2220         if (!space_info) {
2221                 ret = update_space_info(extent_root->fs_info, flags,
2222                                         0, 0, &space_info);
2223                 BUG_ON(ret);
2224         }
2225         BUG_ON(!space_info);
2226
2227         spin_lock(&space_info->lock);
2228         if (space_info->force_alloc) {
2229                 force = 1;
2230                 space_info->force_alloc = 0;
2231         }
2232         if (space_info->full) {
2233                 spin_unlock(&space_info->lock);
2234                 goto out;
2235         }
2236
2237         thresh = space_info->total_bytes - space_info->bytes_readonly;
2238         thresh = div_factor(thresh, 6);
2239         if (!force &&
2240            (space_info->bytes_used + space_info->bytes_pinned +
2241             space_info->bytes_reserved + alloc_bytes) < thresh) {
2242                 spin_unlock(&space_info->lock);
2243                 goto out;
2244         }
2245         spin_unlock(&space_info->lock);
2246
2247         ret = btrfs_alloc_chunk(trans, extent_root, flags);
2248         if (ret)
2249                 space_info->full = 1;
2250 out:
2251         mutex_unlock(&extent_root->fs_info->chunk_mutex);
2252         return ret;
2253 }
2254
2255 static int update_block_group(struct btrfs_trans_handle *trans,
2256                               struct btrfs_root *root,
2257                               u64 bytenr, u64 num_bytes, int alloc,
2258                               int mark_free)
2259 {
2260         struct btrfs_block_group_cache *cache;
2261         struct btrfs_fs_info *info = root->fs_info;
2262         u64 total = num_bytes;
2263         u64 old_val;
2264         u64 byte_in_group;
2265
2266         while (total) {
2267                 cache = btrfs_lookup_block_group(info, bytenr);
2268                 if (!cache)
2269                         return -1;
2270                 byte_in_group = bytenr - cache->key.objectid;
2271                 WARN_ON(byte_in_group > cache->key.offset);
2272
2273                 spin_lock(&cache->space_info->lock);
2274                 spin_lock(&cache->lock);
2275                 cache->dirty = 1;
2276                 old_val = btrfs_block_group_used(&cache->item);
2277                 num_bytes = min(total, cache->key.offset - byte_in_group);
2278                 if (alloc) {
2279                         old_val += num_bytes;
2280                         cache->space_info->bytes_used += num_bytes;
2281                         if (cache->ro)
2282                                 cache->space_info->bytes_readonly -= num_bytes;
2283                         btrfs_set_block_group_used(&cache->item, old_val);
2284                         spin_unlock(&cache->lock);
2285                         spin_unlock(&cache->space_info->lock);
2286                 } else {
2287                         old_val -= num_bytes;
2288                         cache->space_info->bytes_used -= num_bytes;
2289                         if (cache->ro)
2290                                 cache->space_info->bytes_readonly += num_bytes;
2291                         btrfs_set_block_group_used(&cache->item, old_val);
2292                         spin_unlock(&cache->lock);
2293                         spin_unlock(&cache->space_info->lock);
2294                         if (mark_free) {
2295                                 int ret;
2296
2297                                 ret = btrfs_discard_extent(root, bytenr,
2298                                                            num_bytes);
2299                                 WARN_ON(ret);
2300
2301                                 ret = btrfs_add_free_space(cache, bytenr,
2302                                                            num_bytes);
2303                                 WARN_ON(ret);
2304                         }
2305                 }
2306                 put_block_group(cache);
2307                 total -= num_bytes;
2308                 bytenr += num_bytes;
2309         }
2310         return 0;
2311 }
2312
2313 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
2314 {
2315         struct btrfs_block_group_cache *cache;
2316         u64 bytenr;
2317
2318         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
2319         if (!cache)
2320                 return 0;
2321
2322         bytenr = cache->key.objectid;
2323         put_block_group(cache);
2324
2325         return bytenr;
2326 }
2327
2328 int btrfs_update_pinned_extents(struct btrfs_root *root,
2329                                 u64 bytenr, u64 num, int pin)
2330 {
2331         u64 len;
2332         struct btrfs_block_group_cache *cache;
2333         struct btrfs_fs_info *fs_info = root->fs_info;
2334
2335         WARN_ON(!mutex_is_locked(&root->fs_info->pinned_mutex));
2336         if (pin) {
2337                 set_extent_dirty(&fs_info->pinned_extents,
2338                                 bytenr, bytenr + num - 1, GFP_NOFS);
2339         } else {
2340                 clear_extent_dirty(&fs_info->pinned_extents,
2341                                 bytenr, bytenr + num - 1, GFP_NOFS);
2342         }
2343         while (num > 0) {
2344                 cache = btrfs_lookup_block_group(fs_info, bytenr);
2345                 BUG_ON(!cache);
2346                 len = min(num, cache->key.offset -
2347                           (bytenr - cache->key.objectid));
2348                 if (pin) {
2349                         spin_lock(&cache->space_info->lock);
2350                         spin_lock(&cache->lock);
2351                         cache->pinned += len;
2352                         cache->space_info->bytes_pinned += len;
2353                         spin_unlock(&cache->lock);
2354                         spin_unlock(&cache->space_info->lock);
2355                         fs_info->total_pinned += len;
2356                 } else {
2357                         spin_lock(&cache->space_info->lock);
2358                         spin_lock(&cache->lock);
2359                         cache->pinned -= len;
2360                         cache->space_info->bytes_pinned -= len;
2361                         spin_unlock(&cache->lock);
2362                         spin_unlock(&cache->space_info->lock);
2363                         fs_info->total_pinned -= len;
2364                         if (cache->cached)
2365                                 btrfs_add_free_space(cache, bytenr, len);
2366                 }
2367                 put_block_group(cache);
2368                 bytenr += len;
2369                 num -= len;
2370         }
2371         return 0;
2372 }
2373
2374 static int update_reserved_extents(struct btrfs_root *root,
2375                                    u64 bytenr, u64 num, int reserve)
2376 {
2377         u64 len;
2378         struct btrfs_block_group_cache *cache;
2379         struct btrfs_fs_info *fs_info = root->fs_info;
2380
2381         while (num > 0) {
2382                 cache = btrfs_lookup_block_group(fs_info, bytenr);
2383                 BUG_ON(!cache);
2384                 len = min(num, cache->key.offset -
2385                           (bytenr - cache->key.objectid));
2386
2387                 spin_lock(&cache->space_info->lock);
2388                 spin_lock(&cache->lock);
2389                 if (reserve) {
2390                         cache->reserved += len;
2391                         cache->space_info->bytes_reserved += len;
2392                 } else {
2393                         cache->reserved -= len;
2394                         cache->space_info->bytes_reserved -= len;
2395                 }
2396                 spin_unlock(&cache->lock);
2397                 spin_unlock(&cache->space_info->lock);
2398                 put_block_group(cache);
2399                 bytenr += len;
2400                 num -= len;
2401         }
2402         return 0;
2403 }
2404
2405 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
2406 {
2407         u64 last = 0;
2408         u64 start;
2409         u64 end;
2410         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
2411         int ret;
2412
2413         mutex_lock(&root->fs_info->pinned_mutex);
2414         while (1) {
2415                 ret = find_first_extent_bit(pinned_extents, last,
2416                                             &start, &end, EXTENT_DIRTY);
2417                 if (ret)
2418                         break;
2419                 set_extent_dirty(copy, start, end, GFP_NOFS);
2420                 last = end + 1;
2421         }
2422         mutex_unlock(&root->fs_info->pinned_mutex);
2423         return 0;
2424 }
2425
2426 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
2427                                struct btrfs_root *root,
2428                                struct extent_io_tree *unpin)
2429 {
2430         u64 start;
2431         u64 end;
2432         int ret;
2433
2434         mutex_lock(&root->fs_info->pinned_mutex);
2435         while (1) {
2436                 ret = find_first_extent_bit(unpin, 0, &start, &end,
2437                                             EXTENT_DIRTY);
2438                 if (ret)
2439                         break;
2440
2441                 ret = btrfs_discard_extent(root, start, end + 1 - start);
2442
2443                 btrfs_update_pinned_extents(root, start, end + 1 - start, 0);
2444                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
2445
2446                 if (need_resched()) {
2447                         mutex_unlock(&root->fs_info->pinned_mutex);
2448                         cond_resched();
2449                         mutex_lock(&root->fs_info->pinned_mutex);
2450                 }
2451         }
2452         mutex_unlock(&root->fs_info->pinned_mutex);
2453         return ret;
2454 }
2455
2456 static int finish_current_insert(struct btrfs_trans_handle *trans,
2457                                  struct btrfs_root *extent_root, int all)
2458 {
2459         u64 start;
2460         u64 end;
2461         u64 priv;
2462         u64 search = 0;
2463         struct btrfs_fs_info *info = extent_root->fs_info;
2464         struct btrfs_path *path;
2465         struct pending_extent_op *extent_op, *tmp;
2466         struct list_head insert_list, update_list;
2467         int ret;
2468         int num_inserts = 0, max_inserts, restart = 0;
2469
2470         path = btrfs_alloc_path();
2471         INIT_LIST_HEAD(&insert_list);
2472         INIT_LIST_HEAD(&update_list);
2473
2474         max_inserts = extent_root->leafsize /
2475                 (2 * sizeof(struct btrfs_key) + 2 * sizeof(struct btrfs_item) +
2476                  sizeof(struct btrfs_extent_ref) +
2477                  sizeof(struct btrfs_extent_item));
2478 again:
2479         mutex_lock(&info->extent_ins_mutex);
2480         while (1) {
2481                 ret = find_first_extent_bit(&info->extent_ins, search, &start,
2482                                             &end, EXTENT_WRITEBACK);
2483                 if (ret) {
2484                         if (restart && !num_inserts &&
2485                             list_empty(&update_list)) {
2486                                 restart = 0;
2487                                 search = 0;
2488                                 continue;
2489                         }
2490                         break;
2491                 }
2492
2493                 ret = try_lock_extent(&info->extent_ins, start, end, GFP_NOFS);
2494                 if (!ret) {
2495                         if (all)
2496                                 restart = 1;
2497                         search = end + 1;
2498                         if (need_resched()) {
2499                                 mutex_unlock(&info->extent_ins_mutex);
2500                                 cond_resched();
2501                                 mutex_lock(&info->extent_ins_mutex);
2502                         }
2503                         continue;
2504                 }
2505
2506                 ret = get_state_private(&info->extent_ins, start, &priv);
2507                 BUG_ON(ret);
2508                 extent_op = (struct pending_extent_op *)(unsigned long) priv;
2509
2510                 if (extent_op->type == PENDING_EXTENT_INSERT) {
2511                         num_inserts++;
2512                         list_add_tail(&extent_op->list, &insert_list);
2513                         search = end + 1;
2514                         if (num_inserts == max_inserts) {
2515                                 restart = 1;
2516                                 break;
2517                         }
2518                 } else if (extent_op->type == PENDING_BACKREF_UPDATE) {
2519                         list_add_tail(&extent_op->list, &update_list);
2520                         search = end + 1;
2521                 } else {
2522                         BUG();
2523                 }
2524         }
2525
2526         /*
2527          * process the update list, clear the writeback bit for it, and if
2528          * somebody marked this thing for deletion then just unlock it and be
2529          * done, the free_extents will handle it
2530          */
2531         list_for_each_entry_safe(extent_op, tmp, &update_list, list) {
2532                 clear_extent_bits(&info->extent_ins, extent_op->bytenr,
2533                                   extent_op->bytenr + extent_op->num_bytes - 1,
2534                                   EXTENT_WRITEBACK, GFP_NOFS);
2535                 if (extent_op->del) {
2536                         list_del_init(&extent_op->list);
2537                         unlock_extent(&info->extent_ins, extent_op->bytenr,
2538                                       extent_op->bytenr + extent_op->num_bytes
2539                                       - 1, GFP_NOFS);
2540                         kfree(extent_op);
2541                 }
2542         }
2543         mutex_unlock(&info->extent_ins_mutex);
2544
2545         /*
2546          * still have things left on the update list, go ahead an update
2547          * everything
2548          */
2549         if (!list_empty(&update_list)) {
2550                 ret = update_backrefs(trans, extent_root, path, &update_list);
2551                 BUG_ON(ret);
2552
2553                 /* we may have COW'ed new blocks, so lets start over */
2554                 if (all)
2555                         restart = 1;
2556         }
2557
2558         /*
2559          * if no inserts need to be done, but we skipped some extents and we
2560          * need to make sure everything is cleaned then reset everything and
2561          * go back to the beginning
2562          */
2563         if (!num_inserts && restart) {
2564                 search = 0;
2565                 restart = 0;
2566                 INIT_LIST_HEAD(&update_list);
2567                 INIT_LIST_HEAD(&insert_list);
2568                 goto again;
2569         } else if (!num_inserts) {
2570                 goto out;
2571         }
2572
2573         /*
2574          * process the insert extents list.  Again if we are deleting this
2575          * extent, then just unlock it, pin down the bytes if need be, and be
2576          * done with it.  Saves us from having to actually insert the extent
2577          * into the tree and then subsequently come along and delete it
2578          */
2579         mutex_lock(&info->extent_ins_mutex);
2580         list_for_each_entry_safe(extent_op, tmp, &insert_list, list) {
2581                 clear_extent_bits(&info->extent_ins, extent_op->bytenr,
2582                                   extent_op->bytenr + extent_op->num_bytes - 1,
2583                                   EXTENT_WRITEBACK, GFP_NOFS);
2584                 if (extent_op->del) {
2585                         u64 used;
2586                         list_del_init(&extent_op->list);
2587                         unlock_extent(&info->extent_ins, extent_op->bytenr,
2588                                       extent_op->bytenr + extent_op->num_bytes
2589                                       - 1, GFP_NOFS);
2590
2591                         mutex_lock(&extent_root->fs_info->pinned_mutex);
2592                         ret = pin_down_bytes(trans, extent_root,
2593                                              extent_op->bytenr,
2594                                              extent_op->num_bytes, 0);
2595                         mutex_unlock(&extent_root->fs_info->pinned_mutex);
2596
2597                         spin_lock(&info->delalloc_lock);
2598                         used = btrfs_super_bytes_used(&info->super_copy);
2599                         btrfs_set_super_bytes_used(&info->super_copy,
2600                                         used - extent_op->num_bytes);
2601                         used = btrfs_root_used(&extent_root->root_item);
2602                         btrfs_set_root_used(&extent_root->root_item,
2603                                         used - extent_op->num_bytes);
2604                         spin_unlock(&info->delalloc_lock);
2605
2606                         ret = update_block_group(trans, extent_root,
2607                                                  extent_op->bytenr,
2608                                                  extent_op->num_bytes,
2609                                                  0, ret > 0);
2610                         BUG_ON(ret);
2611                         kfree(extent_op);
2612                         num_inserts--;
2613                 }
2614         }
2615         mutex_unlock(&info->extent_ins_mutex);
2616
2617         ret = insert_extents(trans, extent_root, path, &insert_list,
2618                              num_inserts);
2619         BUG_ON(ret);
2620
2621         /*
2622          * if restart is set for whatever reason we need to go back and start
2623          * searching through the pending list again.
2624          *
2625          * We just inserted some extents, which could have resulted in new
2626          * blocks being allocated, which would result in new blocks needing
2627          * updates, so if all is set we _must_ restart to get the updated
2628          * blocks.
2629          */
2630         if (restart || all) {
2631                 INIT_LIST_HEAD(&insert_list);
2632                 INIT_LIST_HEAD(&update_list);
2633                 search = 0;
2634                 restart = 0;
2635                 num_inserts = 0;
2636                 goto again;
2637         }
2638 out:
2639         btrfs_free_path(path);
2640         return 0;
2641 }
2642
2643 static int pin_down_bytes(struct btrfs_trans_handle *trans,
2644                           struct btrfs_root *root,
2645                           u64 bytenr, u64 num_bytes, int is_data)
2646 {
2647         int err = 0;
2648         struct extent_buffer *buf;
2649
2650         if (is_data)
2651                 goto pinit;
2652
2653         buf = btrfs_find_tree_block(root, bytenr, num_bytes);
2654         if (!buf)
2655                 goto pinit;
2656
2657         /* we can reuse a block if it hasn't been written
2658          * and it is from this transaction.  We can't
2659          * reuse anything from the tree log root because
2660          * it has tiny sub-transactions.
2661          */
2662         if (btrfs_buffer_uptodate(buf, 0) &&
2663             btrfs_try_tree_lock(buf)) {
2664                 u64 header_owner = btrfs_header_owner(buf);
2665                 u64 header_transid = btrfs_header_generation(buf);
2666                 if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
2667                     header_owner != BTRFS_TREE_RELOC_OBJECTID &&
2668                     header_transid == trans->transid &&
2669                     !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
2670                         clean_tree_block(NULL, root, buf);
2671                         btrfs_tree_unlock(buf);
2672                         free_extent_buffer(buf);
2673                         return 1;
2674                 }
2675                 btrfs_tree_unlock(buf);
2676         }
2677         free_extent_buffer(buf);
2678 pinit:
2679         btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
2680
2681         BUG_ON(err < 0);
2682         return 0;
2683 }
2684
2685 /*
2686  * remove an extent from the root, returns 0 on success
2687  */
2688 static int __free_extent(struct btrfs_trans_handle *trans,
2689                          struct btrfs_root *root,
2690                          u64 bytenr, u64 num_bytes, u64 parent,
2691                          u64 root_objectid, u64 ref_generation,
2692                          u64 owner_objectid, int pin, int mark_free)
2693 {
2694         struct btrfs_path *path;
2695         struct btrfs_key key;
2696         struct btrfs_fs_info *info = root->fs_info;
2697         struct btrfs_root *extent_root = info->extent_root;
2698         struct extent_buffer *leaf;
2699         int ret;
2700         int extent_slot = 0;
2701         int found_extent = 0;
2702         int num_to_del = 1;
2703         struct btrfs_extent_item *ei;
2704         u32 refs;
2705
2706         key.objectid = bytenr;
2707         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
2708         key.offset = num_bytes;
2709         path = btrfs_alloc_path();
2710         if (!path)
2711                 return -ENOMEM;
2712
2713         path->reada = 1;
2714         ret = lookup_extent_backref(trans, extent_root, path,
2715                                     bytenr, parent, root_objectid,
2716                                     ref_generation, owner_objectid, 1);
2717         if (ret == 0) {
2718                 struct btrfs_key found_key;
2719                 extent_slot = path->slots[0];
2720                 while (extent_slot > 0) {
2721                         extent_slot--;
2722                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2723                                               extent_slot);
2724                         if (found_key.objectid != bytenr)
2725                                 break;
2726                         if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
2727                             found_key.offset == num_bytes) {
2728                                 found_extent = 1;
2729                                 break;
2730                         }
2731                         if (path->slots[0] - extent_slot > 5)
2732                                 break;
2733                 }
2734                 if (!found_extent) {
2735                         ret = remove_extent_backref(trans, extent_root, path);
2736                         BUG_ON(ret);
2737                         btrfs_release_path(extent_root, path);
2738                         ret = btrfs_search_slot(trans, extent_root,
2739                                                 &key, path, -1, 1);
2740                         if (ret) {
2741                                 printk(KERN_ERR "umm, got %d back from search"
2742                                        ", was looking for %llu\n", ret,
2743                                        (unsigned long long)bytenr);
2744                                 btrfs_print_leaf(extent_root, path->nodes[0]);
2745                         }
2746                         BUG_ON(ret);
2747                         extent_slot = path->slots[0];
2748                 }
2749         } else {
2750                 btrfs_print_leaf(extent_root, path->nodes[0]);
2751                 WARN_ON(1);
2752                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
2753                        "root %llu gen %llu owner %llu\n",
2754                        (unsigned long long)bytenr,
2755                        (unsigned long long)root_objectid,
2756                        (unsigned long long)ref_generation,
2757                        (unsigned long long)owner_objectid);
2758         }
2759
2760         leaf = path->nodes[0];
2761         ei = btrfs_item_ptr(leaf, extent_slot,
2762                             struct btrfs_extent_item);
2763         refs = btrfs_extent_refs(leaf, ei);
2764         BUG_ON(refs == 0);
2765         refs -= 1;
2766         btrfs_set_extent_refs(leaf, ei, refs);
2767
2768         btrfs_mark_buffer_dirty(leaf);
2769
2770         if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
2771                 struct btrfs_extent_ref *ref;
2772                 ref = btrfs_item_ptr(leaf, path->slots[0],
2773                                      struct btrfs_extent_ref);
2774                 BUG_ON(btrfs_ref_num_refs(leaf, ref) != 1);
2775                 /* if the back ref and the extent are next to each other
2776                  * they get deleted below in one shot
2777                  */
2778                 path->slots[0] = extent_slot;
2779                 num_to_del = 2;
2780         } else if (found_extent) {
2781                 /* otherwise delete the extent back ref */
2782                 ret = remove_extent_backref(trans, extent_root, path);
2783                 BUG_ON(ret);
2784                 /* if refs are 0, we need to setup the path for deletion */
2785                 if (refs == 0) {
2786                         btrfs_release_path(extent_root, path);
2787                         ret = btrfs_search_slot(trans, extent_root, &key, path,
2788                                                 -1, 1);
2789                         BUG_ON(ret);
2790                 }
2791         }
2792
2793         if (refs == 0) {
2794                 u64 super_used;
2795                 u64 root_used;
2796
2797                 if (pin) {
2798                         mutex_lock(&root->fs_info->pinned_mutex);
2799                         ret = pin_down_bytes(trans, root, bytenr, num_bytes,
2800                                 owner_objectid >= BTRFS_FIRST_FREE_OBJECTID);
2801                         mutex_unlock(&root->fs_info->pinned_mutex);
2802                         if (ret > 0)
2803                                 mark_free = 1;
2804                         BUG_ON(ret < 0);
2805                 }
2806                 /* block accounting for super block */
2807                 spin_lock(&info->delalloc_lock);
2808                 super_used = btrfs_super_bytes_used(&info->super_copy);
2809                 btrfs_set_super_bytes_used(&info->super_copy,
2810                                            super_used - num_bytes);
2811
2812                 /* block accounting for root item */
2813                 root_used = btrfs_root_used(&root->root_item);
2814                 btrfs_set_root_used(&root->root_item,
2815                                            root_used - num_bytes);
2816                 spin_unlock(&info->delalloc_lock);
2817                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
2818                                       num_to_del);
2819                 BUG_ON(ret);
2820                 btrfs_release_path(extent_root, path);
2821
2822                 if (owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2823                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
2824                         BUG_ON(ret);
2825                 }
2826
2827                 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
2828                                          mark_free);
2829                 BUG_ON(ret);
2830         }
2831         btrfs_free_path(path);
2832         finish_current_insert(trans, extent_root, 0);
2833         return ret;
2834 }
2835
2836 /*
2837  * find all the blocks marked as pending in the radix tree and remove
2838  * them from the extent map
2839  */
2840 static int del_pending_extents(struct btrfs_trans_handle *trans,
2841                                struct btrfs_root *extent_root, int all)
2842 {
2843         int ret;
2844         int err = 0;
2845         u64 start;
2846         u64 end;
2847         u64 priv;
2848         u64 search = 0;
2849         int nr = 0, skipped = 0;
2850         struct extent_io_tree *pending_del;
2851         struct extent_io_tree *extent_ins;
2852         struct pending_extent_op *extent_op;
2853         struct btrfs_fs_info *info = extent_root->fs_info;
2854         struct list_head delete_list;
2855
2856         INIT_LIST_HEAD(&delete_list);
2857         extent_ins = &extent_root->fs_info->extent_ins;
2858         pending_del = &extent_root->fs_info->pending_del;
2859
2860 again:
2861         mutex_lock(&info->extent_ins_mutex);
2862         while (1) {
2863                 ret = find_first_extent_bit(pending_del, search, &start, &end,
2864                                             EXTENT_WRITEBACK);
2865                 if (ret) {
2866                         if (all && skipped && !nr) {
2867                                 search = 0;
2868                                 skipped = 0;
2869                                 continue;
2870                         }
2871                         mutex_unlock(&info->extent_ins_mutex);
2872                         break;
2873                 }
2874
2875                 ret = try_lock_extent(extent_ins, start, end, GFP_NOFS);
2876                 if (!ret) {
2877                         search = end+1;
2878                         skipped = 1;
2879
2880                         if (need_resched()) {
2881                                 mutex_unlock(&info->extent_ins_mutex);
2882                                 cond_resched();
2883                                 mutex_lock(&info->extent_ins_mutex);
2884                         }
2885
2886                         continue;
2887                 }
2888                 BUG_ON(ret < 0);
2889
2890                 ret = get_state_private(pending_del, start, &priv);
2891                 BUG_ON(ret);
2892                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
2893
2894                 clear_extent_bits(pending_del, start, end, EXTENT_WRITEBACK,
2895                                   GFP_NOFS);
2896                 if (!test_range_bit(extent_ins, start, end,
2897                                     EXTENT_WRITEBACK, 0)) {
2898                         list_add_tail(&extent_op->list, &delete_list);
2899                         nr++;
2900                 } else {
2901                         kfree(extent_op);
2902
2903                         ret = get_state_private(&info->extent_ins, start,
2904                                                 &priv);
2905                         BUG_ON(ret);
2906                         extent_op = (struct pending_extent_op *)
2907                                                 (unsigned long)priv;
2908
2909                         clear_extent_bits(&info->extent_ins, start, end,
2910                                           EXTENT_WRITEBACK, GFP_NOFS);
2911
2912                         if (extent_op->type == PENDING_BACKREF_UPDATE) {
2913                                 list_add_tail(&extent_op->list, &delete_list);
2914                                 search = end + 1;
2915                                 nr++;
2916                                 continue;
2917                         }
2918
2919                         mutex_lock(&extent_root->fs_info->pinned_mutex);
2920                         ret = pin_down_bytes(trans, extent_root, start,
2921                                              end + 1 - start, 0);
2922                         mutex_unlock(&extent_root->fs_info->pinned_mutex);
2923
2924                         ret = update_block_group(trans, extent_root, start,
2925                                                 end + 1 - start, 0, ret > 0);
2926
2927                         unlock_extent(extent_ins, start, end, GFP_NOFS);
2928                         BUG_ON(ret);
2929                         kfree(extent_op);
2930                 }
2931                 if (ret)
2932                         err = ret;
2933
2934                 search = end + 1;
2935
2936                 if (need_resched()) {
2937                         mutex_unlock(&info->extent_ins_mutex);
2938                         cond_resched();
2939                         mutex_lock(&info->extent_ins_mutex);
2940                 }
2941         }
2942
2943         if (nr) {
2944                 ret = free_extents(trans, extent_root, &delete_list);
2945                 BUG_ON(ret);
2946         }
2947
2948         if (all && skipped) {
2949                 INIT_LIST_HEAD(&delete_list);
2950                 search = 0;
2951                 nr = 0;
2952                 goto again;
2953         }
2954
2955         if (!err)
2956                 finish_current_insert(trans, extent_root, 0);
2957         return err;
2958 }
2959
2960 /*
2961  * remove an extent from the root, returns 0 on success
2962  */
2963 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
2964                                struct btrfs_root *root,
2965                                u64 bytenr, u64 num_bytes, u64 parent,
2966                                u64 root_objectid, u64 ref_generation,
2967                                u64 owner_objectid, int pin)
2968 {
2969         struct btrfs_root *extent_root = root->fs_info->extent_root;
2970         int pending_ret;
2971         int ret;
2972
2973         WARN_ON(num_bytes < root->sectorsize);
2974         if (root == extent_root) {
2975                 struct pending_extent_op *extent_op = NULL;
2976
2977                 mutex_lock(&root->fs_info->extent_ins_mutex);
2978                 if (test_range_bit(&root->fs_info->extent_ins, bytenr,
2979                                 bytenr + num_bytes - 1, EXTENT_WRITEBACK, 0)) {
2980                         u64 priv;
2981                         ret = get_state_private(&root->fs_info->extent_ins,
2982                                                 bytenr, &priv);
2983                         BUG_ON(ret);
2984                         extent_op = (struct pending_extent_op *)
2985                                                 (unsigned long)priv;
2986
2987                         extent_op->del = 1;
2988                         if (extent_op->type == PENDING_EXTENT_INSERT) {
2989                                 mutex_unlock(&root->fs_info->extent_ins_mutex);
2990                                 return 0;
2991                         }
2992                 }
2993
2994                 if (extent_op) {
2995                         ref_generation = extent_op->orig_generation;
2996                         parent = extent_op->orig_parent;
2997                 }
2998
2999                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
3000                 BUG_ON(!extent_op);
3001
3002                 extent_op->type = PENDING_EXTENT_DELETE;
3003                 extent_op->bytenr = bytenr;
3004                 extent_op->num_bytes = num_bytes;
3005                 extent_op->parent = parent;
3006                 extent_op->orig_parent = parent;
3007                 extent_op->generation = ref_generation;
3008                 extent_op->orig_generation = ref_generation;
3009                 extent_op->level = (int)owner_objectid;
3010                 INIT_LIST_HEAD(&extent_op->list);
3011                 extent_op->del = 0;
3012
3013                 set_extent_bits(&root->fs_info->pending_del,
3014                                 bytenr, bytenr + num_bytes - 1,
3015                                 EXTENT_WRITEBACK, GFP_NOFS);
3016                 set_state_private(&root->fs_info->pending_del,
3017                                   bytenr, (unsigned long)extent_op);
3018                 mutex_unlock(&root->fs_info->extent_ins_mutex);
3019                 return 0;
3020         }
3021         /* if metadata always pin */
3022         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
3023                 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
3024                         mutex_lock(&root->fs_info->pinned_mutex);
3025                         btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
3026                         mutex_unlock(&root->fs_info->pinned_mutex);
3027                         update_reserved_extents(root, bytenr, num_bytes, 0);
3028                         return 0;
3029                 }
3030                 pin = 1;
3031         }
3032
3033         /* if data pin when any transaction has committed this */
3034         if (ref_generation != trans->transid)
3035                 pin = 1;
3036
3037         ret = __free_extent(trans, root, bytenr, num_bytes, parent,
3038                             root_objectid, ref_generation,
3039                             owner_objectid, pin, pin == 0);
3040
3041         finish_current_insert(trans, root->fs_info->extent_root, 0);
3042         pending_ret = del_pending_extents(trans, root->fs_info->extent_root, 0);
3043         return ret ? ret : pending_ret;
3044 }
3045
3046 int btrfs_free_extent(struct btrfs_trans_handle *trans,
3047                       struct btrfs_root *root,
3048                       u64 bytenr, u64 num_bytes, u64 parent,
3049                       u64 root_objectid, u64 ref_generation,
3050                       u64 owner_objectid, int pin)
3051 {
3052         int ret;
3053
3054         ret = __btrfs_free_extent(trans, root, bytenr, num_bytes, parent,
3055                                   root_objectid, ref_generation,
3056                                   owner_objectid, pin);
3057         return ret;
3058 }
3059
3060 static u64 stripe_align(struct btrfs_root *root, u64 val)
3061 {
3062         u64 mask = ((u64)root->stripesize - 1);
3063         u64 ret = (val + mask) & ~mask;
3064         return ret;
3065 }
3066
3067 /*
3068  * walks the btree of allocated extents and find a hole of a given size.
3069  * The key ins is changed to record the hole:
3070  * ins->objectid == block start
3071  * ins->flags = BTRFS_EXTENT_ITEM_KEY
3072  * ins->offset == number of blocks
3073  * Any available blocks before search_start are skipped.
3074  */
3075 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
3076                                      struct btrfs_root *orig_root,
3077                                      u64 num_bytes, u64 empty_size,
3078                                      u64 search_start, u64 search_end,
3079                                      u64 hint_byte, struct btrfs_key *ins,
3080                                      u64 exclude_start, u64 exclude_nr,
3081                                      int data)
3082 {
3083         int ret = 0;
3084         struct btrfs_root *root = orig_root->fs_info->extent_root;
3085         u64 total_needed = num_bytes;
3086         u64 *last_ptr = NULL;
3087         u64 last_wanted = 0;
3088         struct btrfs_block_group_cache *block_group = NULL;
3089         int chunk_alloc_done = 0;
3090         int empty_cluster = 2 * 1024 * 1024;
3091         int allowed_chunk_alloc = 0;
3092         struct list_head *head = NULL, *cur = NULL;
3093         int loop = 0;
3094         int extra_loop = 0;
3095         struct btrfs_space_info *space_info;
3096
3097         WARN_ON(num_bytes < root->sectorsize);
3098         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
3099         ins->objectid = 0;
3100         ins->offset = 0;
3101
3102         if (orig_root->ref_cows || empty_size)
3103                 allowed_chunk_alloc = 1;
3104
3105         if (data & BTRFS_BLOCK_GROUP_METADATA) {
3106                 last_ptr = &root->fs_info->last_alloc;
3107                 if (!btrfs_test_opt(root, SSD))
3108                         empty_cluster = 64 * 1024;
3109         }
3110
3111         if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD))
3112                 last_ptr = &root->fs_info->last_data_alloc;
3113
3114         if (last_ptr) {
3115                 if (*last_ptr) {
3116                         hint_byte = *last_ptr;
3117                         last_wanted = *last_ptr;
3118                 } else
3119                         empty_size += empty_cluster;
3120         } else {
3121                 empty_cluster = 0;
3122         }
3123         search_start = max(search_start, first_logical_byte(root, 0));
3124         search_start = max(search_start, hint_byte);
3125
3126         if (last_wanted && search_start != last_wanted) {
3127                 last_wanted = 0;
3128                 empty_size += empty_cluster;
3129         }
3130
3131         total_needed += empty_size;
3132         block_group = btrfs_lookup_block_group(root->fs_info, search_start);
3133         if (!block_group)
3134                 block_group = btrfs_lookup_first_block_group(root->fs_info,
3135                                                              search_start);
3136         space_info = __find_space_info(root->fs_info, data);
3137
3138         down_read(&space_info->groups_sem);
3139         while (1) {
3140                 struct btrfs_free_space *free_space;
3141                 /*
3142                  * the only way this happens if our hint points to a block
3143                  * group thats not of the proper type, while looping this
3144                  * should never happen
3145                  */
3146                 if (empty_size)
3147                         extra_loop = 1;
3148
3149                 if (!block_group)
3150                         goto new_group_no_lock;
3151
3152                 if (unlikely(!block_group->cached)) {
3153                         mutex_lock(&block_group->cache_mutex);
3154                         ret = cache_block_group(root, block_group);
3155                         mutex_unlock(&block_group->cache_mutex);
3156                         if (ret)
3157                                 break;
3158                 }
3159
3160                 mutex_lock(&block_group->alloc_mutex);
3161                 if (unlikely(!block_group_bits(block_group, data)))
3162                         goto new_group;
3163
3164                 if (unlikely(block_group->ro))
3165                         goto new_group;
3166
3167                 free_space = btrfs_find_free_space(block_group, search_start,
3168                                                    total_needed);
3169                 if (free_space) {
3170                         u64 start = block_group->key.objectid;
3171                         u64 end = block_group->key.objectid +
3172                                 block_group->key.offset;
3173
3174                         search_start = stripe_align(root, free_space->offset);
3175
3176                         /* move on to the next group */
3177                         if (search_start + num_bytes >= search_end)
3178                                 goto new_group;
3179
3180                         /* move on to the next group */
3181                         if (search_start + num_bytes > end)
3182                                 goto new_group;
3183
3184                         if (last_wanted && search_start != last_wanted) {
3185                                 total_needed += empty_cluster;
3186                                 empty_size += empty_cluster;
3187                                 last_wanted = 0;
3188                                 /*
3189                                  * if search_start is still in this block group
3190                                  * then we just re-search this block group
3191                                  */
3192                                 if (search_start >= start &&
3193                                     search_start < end) {
3194                                         mutex_unlock(&block_group->alloc_mutex);
3195                                         continue;
3196                                 }
3197
3198                                 /* else we go to the next block group */
3199                                 goto new_group;
3200                         }
3201
3202                         if (exclude_nr > 0 &&
3203                             (search_start + num_bytes > exclude_start &&
3204                              search_start < exclude_start + exclude_nr)) {
3205                                 search_start = exclude_start + exclude_nr;
3206                                 /*
3207                                  * if search_start is still in this block group
3208                                  * then we just re-search this block group
3209                                  */
3210                                 if (search_start >= start &&
3211                                     search_start < end) {
3212                                         mutex_unlock(&block_group->alloc_mutex);
3213                                         last_wanted = 0;
3214                                         continue;
3215                                 }
3216
3217                                 /* else we go to the next block group */
3218                                 goto new_group;
3219                         }
3220
3221                         ins->objectid = search_start;
3222                         ins->offset = num_bytes;
3223
3224                         btrfs_remove_free_space_lock(block_group, search_start,
3225                                                      num_bytes);
3226                         /* we are all good, lets return */
3227                         mutex_unlock(&block_group->alloc_mutex);
3228                         break;
3229                 }
3230 new_group:
3231                 mutex_unlock(&block_group->alloc_mutex);
3232                 put_block_group(block_group);
3233                 block_group = NULL;
3234 new_group_no_lock:
3235                 /* don't try to compare new allocations against the
3236                  * last allocation any more
3237                  */
3238                 last_wanted = 0;
3239
3240                 /*
3241                  * Here's how this works.
3242                  * loop == 0: we were searching a block group via a hint
3243                  *              and didn't find anything, so we start at
3244                  *              the head of the block groups and keep searching
3245                  * loop == 1: we're searching through all of the block groups
3246                  *              if we hit the head again we have searched
3247                  *              all of the block groups for this space and we
3248                  *              need to try and allocate, if we cant error out.
3249                  * loop == 2: we allocated more space and are looping through
3250                  *              all of the block groups again.
3251                  */
3252                 if (loop == 0) {
3253                         head = &space_info->block_groups;
3254                         cur = head->next;
3255                         loop++;
3256                 } else if (loop == 1 && cur == head) {
3257                         int keep_going;
3258
3259                         /* at this point we give up on the empty_size
3260                          * allocations and just try to allocate the min
3261                          * space.
3262                          *
3263                          * The extra_loop field was set if an empty_size
3264                          * allocation was attempted above, and if this
3265                          * is try we need to try the loop again without
3266                          * the additional empty_size.
3267                          */
3268                         total_needed -= empty_size;
3269                         empty_size = 0;
3270                         keep_going = extra_loop;
3271                         loop++;
3272
3273                         if (allowed_chunk_alloc && !chunk_alloc_done) {
3274                                 up_read(&space_info->groups_sem);
3275                                 ret = do_chunk_alloc(trans, root, num_bytes +
3276                                                      2 * 1024 * 1024, data, 1);
3277                                 down_read(&space_info->groups_sem);
3278                                 if (ret < 0)
3279                                         goto loop_check;
3280                                 head = &space_info->block_groups;
3281                                 /*
3282                                  * we've allocated a new chunk, keep
3283                                  * trying
3284                                  */
3285                                 keep_going = 1;
3286                                 chunk_alloc_done = 1;
3287                         } else if (!allowed_chunk_alloc) {
3288                                 space_info->force_alloc = 1;
3289                         }
3290 loop_check:
3291                         if (keep_going) {
3292                                 cur = head->next;
3293                                 extra_loop = 0;
3294                         } else {
3295                                 break;
3296                         }
3297                 } else if (cur == head) {
3298                         break;
3299                 }
3300
3301                 block_group = list_entry(cur, struct btrfs_block_group_cache,
3302                                          list);
3303                 atomic_inc(&block_group->count);
3304
3305                 search_start = block_group->key.objectid;
3306                 cur = cur->next;
3307         }
3308
3309         /* we found what we needed */
3310         if (ins->objectid) {
3311                 if (!(data & BTRFS_BLOCK_GROUP_DATA))
3312                         trans->block_group = block_group->key.objectid;
3313
3314                 if (last_ptr)
3315                         *last_ptr = ins->objectid + ins->offset;
3316                 ret = 0;
3317         } else if (!ret) {
3318                 printk(KERN_ERR "btrfs searching for %llu bytes, "
3319                        "num_bytes %llu, loop %d, allowed_alloc %d\n",
3320                        (unsigned long long)total_needed,
3321                        (unsigned long long)num_bytes,
3322                        loop, allowed_chunk_alloc);
3323                 ret = -ENOSPC;
3324         }
3325         if (block_group)
3326                 put_block_group(block_group);
3327
3328         up_read(&space_info->groups_sem);
3329         return ret;
3330 }
3331
3332 static void dump_space_info(struct btrfs_space_info *info, u64 bytes)
3333 {
3334         struct btrfs_block_group_cache *cache;
3335
3336         printk(KERN_INFO "space_info has %llu free, is %sfull\n",
3337                (unsigned long long)(info->total_bytes - info->bytes_used -
3338                                     info->bytes_pinned - info->bytes_reserved),
3339                (info->full) ? "" : "not ");
3340         printk(KERN_INFO "space_info total=%llu, pinned=%llu, delalloc=%llu,"
3341                " may_use=%llu, used=%llu\n", info->total_bytes,
3342                info->bytes_pinned, info->bytes_delalloc, info->bytes_may_use,
3343                info->bytes_used);
3344
3345         down_read(&info->groups_sem);
3346         list_for_each_entry(cache, &info->block_groups, list) {
3347                 spin_lock(&cache->lock);
3348                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
3349                        "%llu pinned %llu reserved\n",
3350                        (unsigned long long)cache->key.objectid,
3351                        (unsigned long long)cache->key.offset,
3352                        (unsigned long long)btrfs_block_group_used(&cache->item),
3353                        (unsigned long long)cache->pinned,
3354                        (unsigned long long)cache->reserved);
3355                 btrfs_dump_free_space(cache, bytes);
3356                 spin_unlock(&cache->lock);
3357         }
3358         up_read(&info->groups_sem);
3359 }
3360
3361 static int __btrfs_reserve_extent(struct btrfs_trans_handle *trans,
3362                                   struct btrfs_root *root,
3363                                   u64 num_bytes, u64 min_alloc_size,
3364                                   u64 empty_size, u64 hint_byte,
3365                                   u64 search_end, struct btrfs_key *ins,
3366                                   u64 data)
3367 {
3368         int ret;
3369         u64 search_start = 0;
3370         struct btrfs_fs_info *info = root->fs_info;
3371
3372         data = btrfs_get_alloc_profile(root, data);
3373 again:
3374         /*
3375          * the only place that sets empty_size is btrfs_realloc_node, which
3376          * is not called recursively on allocations
3377          */
3378         if (empty_size || root->ref_cows) {
3379                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
3380                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3381                                      2 * 1024 * 1024,
3382                                      BTRFS_BLOCK_GROUP_METADATA |
3383                                      (info->metadata_alloc_profile &
3384                                       info->avail_metadata_alloc_bits), 0);
3385                 }
3386                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3387                                      num_bytes + 2 * 1024 * 1024, data, 0);
3388         }
3389
3390         WARN_ON(num_bytes < root->sectorsize);
3391         ret = find_free_extent(trans, root, num_bytes, empty_size,
3392                                search_start, search_end, hint_byte, ins,
3393                                trans->alloc_exclude_start,
3394                                trans->alloc_exclude_nr, data);
3395
3396         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
3397                 num_bytes = num_bytes >> 1;
3398                 num_bytes = num_bytes & ~(root->sectorsize - 1);
3399                 num_bytes = max(num_bytes, min_alloc_size);
3400                 do_chunk_alloc(trans, root->fs_info->extent_root,
3401                                num_bytes, data, 1);
3402                 goto again;
3403         }
3404         if (ret) {
3405                 struct btrfs_space_info *sinfo;
3406
3407                 sinfo = __find_space_info(root->fs_info, data);
3408                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
3409                        "wanted %llu\n", (unsigned long long)data,
3410                        (unsigned long long)num_bytes);
3411                 dump_space_info(sinfo, num_bytes);
3412                 BUG();
3413         }
3414
3415         return ret;
3416 }
3417
3418 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
3419 {
3420         struct btrfs_block_group_cache *cache;
3421         int ret = 0;
3422
3423         cache = btrfs_lookup_block_group(root->fs_info, start);
3424         if (!cache) {
3425                 printk(KERN_ERR "Unable to find block group for %llu\n",
3426                        (unsigned long long)start);
3427                 return -ENOSPC;
3428         }
3429
3430         ret = btrfs_discard_extent(root, start, len);
3431
3432         btrfs_add_free_space(cache, start, len);
3433         put_block_group(cache);
3434         update_reserved_extents(root, start, len, 0);
3435
3436         return ret;
3437 }
3438
3439 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
3440                                   struct btrfs_root *root,
3441                                   u64 num_bytes, u64 min_alloc_size,
3442                                   u64 empty_size, u64 hint_byte,
3443                                   u64 search_end, struct btrfs_key *ins,
3444                                   u64 data)
3445 {
3446         int ret;
3447         ret = __btrfs_reserve_extent(trans, root, num_bytes, min_alloc_size,
3448                                      empty_size, hint_byte, search_end, ins,
3449                                      data);
3450         update_reserved_extents(root, ins->objectid, ins->offset, 1);
3451         return ret;
3452 }
3453
3454 static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
3455                                          struct btrfs_root *root, u64 parent,
3456                                          u64 root_objectid, u64 ref_generation,
3457                                          u64 owner, struct btrfs_key *ins)
3458 {
3459         int ret;
3460         int pending_ret;
3461         u64 super_used;
3462         u64 root_used;
3463         u64 num_bytes = ins->offset;
3464         u32 sizes[2];
3465         struct btrfs_fs_info *info = root->fs_info;
3466         struct btrfs_root *extent_root = info->extent_root;
3467         struct btrfs_extent_item *extent_item;
3468         struct btrfs_extent_ref *ref;
3469         struct btrfs_path *path;
3470         struct btrfs_key keys[2];
3471
3472         if (parent == 0)
3473                 parent = ins->objectid;
3474
3475         /* block accounting for super block */
3476         spin_lock(&info->delalloc_lock);
3477         super_used = btrfs_super_bytes_used(&info->super_copy);
3478         btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
3479
3480         /* block accounting for root item */
3481         root_used = btrfs_root_used(&root->root_item);
3482         btrfs_set_root_used(&root->root_item, root_used + num_bytes);
3483         spin_unlock(&info->delalloc_lock);
3484
3485         if (root == extent_root) {
3486                 struct pending_extent_op *extent_op;
3487
3488                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
3489                 BUG_ON(!extent_op);
3490
3491                 extent_op->type = PENDING_EXTENT_INSERT;
3492                 extent_op->bytenr = ins->objectid;
3493                 extent_op->num_bytes = ins->offset;
3494                 extent_op->parent = parent;
3495                 extent_op->orig_parent = 0;
3496                 extent_op->generation = ref_generation;
3497                 extent_op->orig_generation = 0;
3498                 extent_op->level = (int)owner;
3499                 INIT_LIST_HEAD(&extent_op->list);
3500                 extent_op->del = 0;
3501
3502                 mutex_lock(&root->fs_info->extent_ins_mutex);
3503                 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
3504                                 ins->objectid + ins->offset - 1,
3505                                 EXTENT_WRITEBACK, GFP_NOFS);
3506                 set_state_private(&root->fs_info->extent_ins,
3507                                   ins->objectid, (unsigned long)extent_op);
3508                 mutex_unlock(&root->fs_info->extent_ins_mutex);
3509                 goto update_block;
3510         }
3511
3512         memcpy(&keys[0], ins, sizeof(*ins));
3513         keys[1].objectid = ins->objectid;
3514         keys[1].type = BTRFS_EXTENT_REF_KEY;
3515         keys[1].offset = parent;
3516         sizes[0] = sizeof(*extent_item);
3517         sizes[1] = sizeof(*ref);
3518
3519         path = btrfs_alloc_path();
3520         BUG_ON(!path);
3521
3522         ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
3523                                        sizes, 2);
3524         BUG_ON(ret);
3525
3526         extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
3527                                      struct btrfs_extent_item);
3528         btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
3529         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
3530                              struct btrfs_extent_ref);
3531
3532         btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
3533         btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
3534         btrfs_set_ref_objectid(path->nodes[0], ref, owner);
3535         btrfs_set_ref_num_refs(path->nodes[0], ref, 1);
3536
3537         btrfs_mark_buffer_dirty(path->nodes[0]);
3538
3539         trans->alloc_exclude_start = 0;
3540         trans->alloc_exclude_nr = 0;
3541         btrfs_free_path(path);
3542         finish_current_insert(trans, extent_root, 0);
3543         pending_ret = del_pending_extents(trans, extent_root, 0);
3544
3545         if (ret)
3546                 goto out;
3547         if (pending_ret) {
3548                 ret = pending_ret;
3549                 goto out;
3550         }
3551
3552 update_block:
3553         ret = update_block_group(trans, root, ins->objectid,
3554                                  ins->offset, 1, 0);
3555         if (ret) {
3556                 printk(KERN_ERR "btrfs update block group failed for %llu "
3557                        "%llu\n", (unsigned long long)ins->objectid,
3558                        (unsigned long long)ins->offset);
3559                 BUG();
3560         }
3561 out:
3562         return ret;
3563 }
3564
3565 int btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
3566                                 struct btrfs_root *root, u64 parent,
3567                                 u64 root_objectid, u64 ref_generation,
3568                                 u64 owner, struct btrfs_key *ins)
3569 {
3570         int ret;
3571
3572         if (root_objectid == BTRFS_TREE_LOG_OBJECTID)
3573                 return 0;
3574         ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
3575                                             ref_generation, owner, ins);
3576         update_reserved_extents(root, ins->objectid, ins->offset, 0);
3577         return ret;
3578 }
3579
3580 /*
3581  * this is used by the tree logging recovery code.  It records that
3582  * an extent has been allocated and makes sure to clear the free
3583  * space cache bits as well
3584  */
3585 int btrfs_alloc_logged_extent(struct btrfs_trans_handle *trans,
3586                                 struct btrfs_root *root, u64 parent,
3587                                 u64 root_objectid, u64 ref_generation,
3588                                 u64 owner, struct btrfs_key *ins)
3589 {
3590         int ret;
3591         struct btrfs_block_group_cache *block_group;
3592
3593         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
3594         mutex_lock(&block_group->cache_mutex);
3595         cache_block_group(root, block_group);
3596         mutex_unlock(&block_group->cache_mutex);
3597
3598         ret = btrfs_remove_free_space(block_group, ins->objectid,
3599                                       ins->offset);
3600         BUG_ON(ret);
3601         put_block_group(block_group);
3602         ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
3603                                             ref_generation, owner, ins);
3604         return ret;
3605 }
3606
3607 /*
3608  * finds a free extent and does all the dirty work required for allocation
3609  * returns the key for the extent through ins, and a tree buffer for
3610  * the first block of the extent through buf.
3611  *
3612  * returns 0 if everything worked, non-zero otherwise.
3613  */
3614 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
3615                        struct btrfs_root *root,
3616                        u64 num_bytes, u64 parent, u64 min_alloc_size,
3617                        u64 root_objectid, u64 ref_generation,
3618                        u64 owner_objectid, u64 empty_size, u64 hint_byte,
3619                        u64 search_end, struct btrfs_key *ins, u64 data)
3620 {
3621         int ret;
3622
3623         ret = __btrfs_reserve_extent(trans, root, num_bytes,
3624                                      min_alloc_size, empty_size, hint_byte,
3625                                      search_end, ins, data);
3626         BUG_ON(ret);
3627         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
3628                 ret = __btrfs_alloc_reserved_extent(trans, root, parent,
3629                                         root_objectid, ref_generation,
3630                                         owner_objectid, ins);
3631                 BUG_ON(ret);
3632
3633         } else {
3634                 update_reserved_extents(root, ins->objectid, ins->offset, 1);
3635         }
3636         return ret;
3637 }
3638
3639 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
3640                                             struct btrfs_root *root,
3641                                             u64 bytenr, u32 blocksize,
3642                                             int level)
3643 {
3644         struct extent_buffer *buf;
3645
3646         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
3647         if (!buf)
3648                 return ERR_PTR(-ENOMEM);
3649         btrfs_set_header_generation(buf, trans->transid);
3650         btrfs_set_buffer_lockdep_class(buf, level);
3651         btrfs_tree_lock(buf);
3652         clean_tree_block(trans, root, buf);
3653
3654         btrfs_set_lock_blocking(buf);
3655         btrfs_set_buffer_uptodate(buf);
3656
3657         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
3658                 set_extent_dirty(&root->dirty_log_pages, buf->start,
3659                          buf->start + buf->len - 1, GFP_NOFS);
3660         } else {
3661                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
3662                          buf->start + buf->len - 1, GFP_NOFS);
3663         }
3664         trans->blocks_used++;
3665         /* this returns a buffer locked for blocking */
3666         return buf;
3667 }
3668
3669 /*
3670  * helper function to allocate a block for a given tree
3671  * returns the tree buffer or NULL.
3672  */
3673 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
3674                                              struct btrfs_root *root,
3675                                              u32 blocksize, u64 parent,
3676                                              u64 root_objectid,
3677                                              u64 ref_generation,
3678                                              int level,
3679                                              u64 hint,
3680                                              u64 empty_size)
3681 {
3682         struct btrfs_key ins;
3683         int ret;
3684         struct extent_buffer *buf;
3685
3686         ret = btrfs_alloc_extent(trans, root, blocksize, parent, blocksize,
3687                                  root_objectid, ref_generation, level,
3688                                  empty_size, hint, (u64)-1, &ins, 0);
3689         if (ret) {
3690                 BUG_ON(ret > 0);
3691                 return ERR_PTR(ret);
3692         }
3693
3694         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
3695                                     blocksize, level);
3696         return buf;
3697 }
3698
3699 int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
3700                         struct btrfs_root *root, struct extent_buffer *leaf)
3701 {
3702         u64 leaf_owner;
3703         u64 leaf_generation;
3704         struct refsort *sorted;
3705         struct btrfs_key key;
3706         struct btrfs_file_extent_item *fi;
3707         int i;
3708         int nritems;
3709         int ret;
3710         int refi = 0;
3711         int slot;
3712
3713         BUG_ON(!btrfs_is_leaf(leaf));
3714         nritems = btrfs_header_nritems(leaf);
3715         leaf_owner = btrfs_header_owner(leaf);
3716         leaf_generation = btrfs_header_generation(leaf);
3717
3718         sorted = kmalloc(sizeof(*sorted) * nritems, GFP_NOFS);
3719         /* we do this loop twice.  The first time we build a list
3720          * of the extents we have a reference on, then we sort the list
3721          * by bytenr.  The second time around we actually do the
3722          * extent freeing.
3723          */
3724         for (i = 0; i < nritems; i++) {
3725                 u64 disk_bytenr;
3726                 cond_resched();
3727
3728                 btrfs_item_key_to_cpu(leaf, &key, i);
3729
3730                 /* only extents have references, skip everything else */
3731                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3732                         continue;
3733
3734                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
3735
3736                 /* inline extents live in the btree, they don't have refs */
3737                 if (btrfs_file_extent_type(leaf, fi) ==
3738                     BTRFS_FILE_EXTENT_INLINE)
3739                         continue;
3740
3741                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
3742
3743                 /* holes don't have refs */
3744                 if (disk_bytenr == 0)
3745                         continue;
3746
3747                 sorted[refi].bytenr = disk_bytenr;
3748                 sorted[refi].slot = i;
3749                 refi++;
3750         }
3751
3752         if (refi == 0)
3753                 goto out;
3754
3755         sort(sorted, refi, sizeof(struct refsort), refsort_cmp, NULL);
3756
3757         for (i = 0; i < refi; i++) {
3758                 u64 disk_bytenr;
3759
3760                 disk_bytenr = sorted[i].bytenr;
3761                 slot = sorted[i].slot;
3762
3763                 cond_resched();
3764
3765                 btrfs_item_key_to_cpu(leaf, &key, slot);
3766                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3767                         continue;
3768
3769                 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
3770
3771                 ret = __btrfs_free_extent(trans, root, disk_bytenr,
3772                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
3773                                 leaf->start, leaf_owner, leaf_generation,
3774                                 key.objectid, 0);
3775                 BUG_ON(ret);
3776
3777                 atomic_inc(&root->fs_info->throttle_gen);
3778                 wake_up(&root->fs_info->transaction_throttle);
3779                 cond_resched();
3780         }
3781 out:
3782         kfree(sorted);
3783         return 0;
3784 }
3785
3786 static noinline int cache_drop_leaf_ref(struct btrfs_trans_handle *trans,
3787                                         struct btrfs_root *root,
3788                                         struct btrfs_leaf_ref *ref)
3789 {
3790         int i;
3791         int ret;
3792         struct btrfs_extent_info *info;
3793         struct refsort *sorted;
3794
3795         if (ref->nritems == 0)
3796                 return 0;
3797
3798         sorted = kmalloc(sizeof(*sorted) * ref->nritems, GFP_NOFS);
3799         for (i = 0; i < ref->nritems; i++) {
3800                 sorted[i].bytenr = ref->extents[i].bytenr;
3801                 sorted[i].slot = i;
3802         }
3803         sort(sorted, ref->nritems, sizeof(struct refsort), refsort_cmp, NULL);
3804
3805         /*
3806          * the items in the ref were sorted when the ref was inserted
3807          * into the ref cache, so this is already in order
3808          */
3809         for (i = 0; i < ref->nritems; i++) {
3810                 info = ref->extents + sorted[i].slot;
3811                 ret = __btrfs_free_extent(trans, root, info->bytenr,
3812                                           info->num_bytes, ref->bytenr,
3813                                           ref->owner, ref->generation,
3814                                           info->objectid, 0);
3815
3816                 atomic_inc(&root->fs_info->throttle_gen);
3817                 wake_up(&root->fs_info->transaction_throttle);
3818                 cond_resched();
3819
3820                 BUG_ON(ret);
3821                 info++;
3822         }
3823
3824         kfree(sorted);
3825         return 0;
3826 }
3827
3828 static int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start,
3829                                      u64 len, u32 *refs)
3830 {
3831         int ret;
3832
3833         ret = btrfs_lookup_extent_ref(NULL, root, start, len, refs);
3834         BUG_ON(ret);
3835
3836 #if 0 /* some debugging code in case we see problems here */
3837         /* if the refs count is one, it won't get increased again.  But
3838          * if the ref count is > 1, someone may be decreasing it at
3839          * the same time we are.
3840          */
3841         if (*refs != 1) {
3842                 struct extent_buffer *eb = NULL;
3843                 eb = btrfs_find_create_tree_block(root, start, len);
3844                 if (eb)
3845                         btrfs_tree_lock(eb);
3846
3847                 mutex_lock(&root->fs_info->alloc_mutex);
3848                 ret = lookup_extent_ref(NULL, root, start, len, refs);
3849                 BUG_ON(ret);
3850                 mutex_unlock(&root->fs_info->alloc_mutex);
3851
3852                 if (eb) {
3853                         btrfs_tree_unlock(eb);
3854                         free_extent_buffer(eb);
3855                 }
3856                 if (*refs == 1) {
3857                         printk(KERN_ERR "btrfs block %llu went down to one "
3858                                "during drop_snap\n", (unsigned long long)start);
3859                 }
3860
3861         }
3862 #endif
3863
3864         cond_resched();
3865         return ret;
3866 }
3867
3868 /*
3869  * this is used while deleting old snapshots, and it drops the refs
3870  * on a whole subtree starting from a level 1 node.
3871  *
3872  * The idea is to sort all the leaf pointers, and then drop the
3873  * ref on all the leaves in order.  Most of the time the leaves
3874  * will have ref cache entries, so no leaf IOs will be required to
3875  * find the extents they have references on.
3876  *
3877  * For each leaf, any references it has are also dropped in order
3878  *
3879  * This ends up dropping the references in something close to optimal
3880  * order for reading and modifying the extent allocation tree.
3881  */
3882 static noinline int drop_level_one_refs(struct btrfs_trans_handle *trans,
3883                                         struct btrfs_root *root,
3884                                         struct btrfs_path *path)
3885 {
3886         u64 bytenr;
3887         u64 root_owner;
3888         u64 root_gen;
3889         struct extent_buffer *eb = path->nodes[1];
3890         struct extent_buffer *leaf;
3891         struct btrfs_leaf_ref *ref;
3892         struct refsort *sorted = NULL;
3893         int nritems = btrfs_header_nritems(eb);
3894         int ret;
3895         int i;
3896         int refi = 0;
3897         int slot = path->slots[1];
3898         u32 blocksize = btrfs_level_size(root, 0);
3899         u32 refs;
3900
3901         if (nritems == 0)
3902                 goto out;
3903
3904         root_owner = btrfs_header_owner(eb);
3905         root_gen = btrfs_header_generation(eb);
3906         sorted = kmalloc(sizeof(*sorted) * nritems, GFP_NOFS);
3907
3908         /*
3909          * step one, sort all the leaf pointers so we don't scribble
3910          * randomly into the extent allocation tree
3911          */
3912         for (i = slot; i < nritems; i++) {
3913                 sorted[refi].bytenr = btrfs_node_blockptr(eb, i);
3914                 sorted[refi].slot = i;
3915                 refi++;
3916         }
3917
3918         /*
3919          * nritems won't be zero, but if we're picking up drop_snapshot
3920          * after a crash, slot might be > 0, so double check things
3921          * just in case.
3922          */
3923         if (refi == 0)
3924                 goto out;
3925
3926         sort(sorted, refi, sizeof(struct refsort), refsort_cmp, NULL);
3927
3928         /*
3929          * the first loop frees everything the leaves point to
3930          */
3931         for (i = 0; i < refi; i++) {
3932                 u64 ptr_gen;
3933
3934                 bytenr = sorted[i].bytenr;
3935
3936                 /*
3937                  * check the reference count on this leaf.  If it is > 1
3938                  * we just decrement it below and don't update any
3939                  * of the refs the leaf points to.
3940                  */
3941                 ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
3942                 BUG_ON(ret);
3943                 if (refs != 1)
3944                         continue;
3945
3946                 ptr_gen = btrfs_node_ptr_generation(eb, sorted[i].slot);
3947
3948                 /*
3949                  * the leaf only had one reference, which means the
3950                  * only thing pointing to this leaf is the snapshot
3951                  * we're deleting.  It isn't possible for the reference
3952                  * count to increase again later
3953                  *
3954                  * The reference cache is checked for the leaf,
3955                  * and if found we'll be able to drop any refs held by
3956                  * the leaf without needing to read it in.
3957                  */
3958                 ref = btrfs_lookup_leaf_ref(root, bytenr);
3959                 if (ref && ref->generation != ptr_gen) {
3960                         btrfs_free_leaf_ref(root, ref);
3961                         ref = NULL;
3962                 }
3963                 if (ref) {
3964                         ret = cache_drop_leaf_ref(trans, root, ref);
3965                         BUG_ON(ret);
3966                         btrfs_remove_leaf_ref(root, ref);
3967                         btrfs_free_leaf_ref(root, ref);
3968                 } else {
3969                         /*
3970                          * the leaf wasn't in the reference cache, so
3971                          * we have to read it.
3972                          */
3973                         leaf = read_tree_block(root, bytenr, blocksize,
3974                                                ptr_gen);
3975                         ret = btrfs_drop_leaf_ref(trans, root, leaf);
3976                         BUG_ON(ret);
3977                         free_extent_buffer(leaf);
3978                 }
3979                 atomic_inc(&root->fs_info->throttle_gen);
3980                 wake_up(&root->fs_info->transaction_throttle);
3981                 cond_resched();
3982         }
3983
3984         /*
3985          * run through the loop again to free the refs on the leaves.
3986          * This is faster than doing it in the loop above because
3987          * the leaves are likely to be clustered together.  We end up
3988          * working in nice chunks on the extent allocation tree.
3989          */
3990         for (i = 0; i < refi; i++) {
3991                 bytenr = sorted[i].bytenr;
3992                 ret = __btrfs_free_extent(trans, root, bytenr,
3993                                         blocksize, eb->start,
3994                                         root_owner, root_gen, 0, 1);
3995                 BUG_ON(ret);
3996
3997                 atomic_inc(&root->fs_info->throttle_gen);
3998                 wake_up(&root->fs_info->transaction_throttle);
3999                 cond_resched();
4000         }
4001 out:
4002         kfree(sorted);
4003
4004         /*
4005          * update the path to show we've processed the entire level 1
4006          * node.  This will get saved into the root's drop_snapshot_progress
4007          * field so these drops are not repeated again if this transaction
4008          * commits.
4009          */
4010         path->slots[1] = nritems;
4011         return 0;
4012 }
4013
4014 /*
4015  * helper function for drop_snapshot, this walks down the tree dropping ref
4016  * counts as it goes.
4017  */
4018 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
4019                                    struct btrfs_root *root,
4020                                    struct btrfs_path *path, int *level)
4021 {
4022         u64 root_owner;
4023         u64 root_gen;
4024         u64 bytenr;
4025         u64 ptr_gen;
4026         struct extent_buffer *next;
4027         struct extent_buffer *cur;
4028         struct extent_buffer *parent;
4029         u32 blocksize;
4030         int ret;
4031         u32 refs;
4032
4033         WARN_ON(*level < 0);
4034         WARN_ON(*level >= BTRFS_MAX_LEVEL);
4035         ret = drop_snap_lookup_refcount(root, path->nodes[*level]->start,
4036                                 path->nodes[*level]->len, &refs);
4037         BUG_ON(ret);
4038         if (refs > 1)
4039                 goto out;
4040
4041         /*
4042          * walk down to the last node level and free all the leaves
4043          */
4044         while (*level >= 0) {
4045                 WARN_ON(*level < 0);
4046                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
4047                 cur = path->nodes[*level];
4048
4049                 if (btrfs_header_level(cur) != *level)
4050                         WARN_ON(1);
4051
4052                 if (path->slots[*level] >=
4053                     btrfs_header_nritems(cur))
4054                         break;
4055
4056                 /* the new code goes down to level 1 and does all the
4057                  * leaves pointed to that node in bulk.  So, this check
4058                  * for level 0 will always be false.
4059                  *
4060                  * But, the disk format allows the drop_snapshot_progress
4061                  * field in the root to leave things in a state where
4062                  * a leaf will need cleaning up here.  If someone crashes
4063                  * with the old code and then boots with the new code,
4064                  * we might find a leaf here.
4065                  */
4066                 if (*level == 0) {
4067                         ret = btrfs_drop_leaf_ref(trans, root, cur);
4068                         BUG_ON(ret);
4069                         break;
4070                 }
4071
4072                 /*
4073                  * once we get to level one, process the whole node
4074                  * at once, including everything below it.
4075                  */
4076                 if (*level == 1) {
4077                         ret = drop_level_one_refs(trans, root, path);
4078                         BUG_ON(ret);
4079                         break;
4080                 }
4081
4082                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
4083                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
4084                 blocksize = btrfs_level_size(root, *level - 1);
4085
4086                 ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
4087                 BUG_ON(ret);
4088
4089                 /*
4090                  * if there is more than one reference, we don't need
4091                  * to read that node to drop any references it has.  We
4092                  * just drop the ref we hold on that node and move on to the
4093                  * next slot in this level.
4094                  */
4095                 if (refs != 1) {
4096                         parent = path->nodes[*level];
4097                         root_owner = btrfs_header_owner(parent);
4098                         root_gen = btrfs_header_generation(parent);
4099                         path->slots[*level]++;
4100
4101                         ret = __btrfs_free_extent(trans, root, bytenr,
4102                                                 blocksize, parent->start,
4103                                                 root_owner, root_gen,
4104                                                 *level - 1, 1);
4105                         BUG_ON(ret);
4106
4107                         atomic_inc(&root->fs_info->throttle_gen);
4108                         wake_up(&root->fs_info->transaction_throttle);
4109                         cond_resched();
4110
4111                         continue;
4112                 }
4113
4114                 /*
4115                  * we need to keep freeing things in the next level down.
4116                  * read the block and loop around to process it
4117                  */
4118                 next = read_tree_block(root, bytenr, blocksize, ptr_gen);
4119                 WARN_ON(*level <= 0);
4120                 if (path->nodes[*level-1])
4121                         free_extent_buffer(path->nodes[*level-1]);
4122                 path->nodes[*level-1] = next;
4123                 *level = btrfs_header_level(next);
4124                 path->slots[*level] = 0;
4125                 cond_resched();
4126         }
4127 out:
4128         WARN_ON(*level < 0);
4129         WARN_ON(*level >= BTRFS_MAX_LEVEL);
4130
4131         if (path->nodes[*level] == root->node) {
4132                 parent = path->nodes[*level];
4133                 bytenr = path->nodes[*level]->start;
4134         } else {
4135                 parent = path->nodes[*level + 1];
4136                 bytenr = btrfs_node_blockptr(parent, path->slots[*level + 1]);
4137         }
4138
4139         blocksize = btrfs_level_size(root, *level);
4140         root_owner = btrfs_header_owner(parent);
4141         root_gen = btrfs_header_generation(parent);
4142
4143         /*
4144          * cleanup and free the reference on the last node
4145          * we processed
4146          */
4147         ret = __btrfs_free_extent(trans, root, bytenr, blocksize,
4148                                   parent->start, root_owner, root_gen,
4149                                   *level, 1);
4150         free_extent_buffer(path->nodes[*level]);
4151         path->nodes[*level] = NULL;
4152
4153         *level += 1;
4154         BUG_ON(ret);
4155
4156         cond_resched();
4157         return 0;
4158 }
4159
4160 /*
4161  * helper function for drop_subtree, this function is similar to
4162  * walk_down_tree. The main difference is that it checks reference
4163  * counts while tree blocks are locked.
4164  */
4165 static noinline int walk_down_subtree(struct btrfs_trans_handle *trans,
4166                                       struct btrfs_root *root,
4167                                       struct btrfs_path *path, int *level)
4168 {
4169         struct extent_buffer *next;
4170         struct extent_buffer *cur;
4171         struct extent_buffer *parent;
4172         u64 bytenr;
4173         u64 ptr_gen;
4174         u32 blocksize;
4175         u32 refs;
4176         int ret;
4177
4178         cur = path->nodes[*level];
4179         ret = btrfs_lookup_extent_ref(trans, root, cur->start, cur->len,
4180                                       &refs);
4181         BUG_ON(ret);
4182         if (refs > 1)
4183                 goto out;
4184
4185         while (*level >= 0) {
4186                 cur = path->nodes[*level];
4187                 if (*level == 0) {
4188                         ret = btrfs_drop_leaf_ref(trans, root, cur);
4189                         BUG_ON(ret);
4190                         clean_tree_block(trans, root, cur);
4191                         break;
4192                 }
4193                 if (path->slots[*level] >= btrfs_header_nritems(cur)) {
4194                         clean_tree_block(trans, root, cur);
4195                         break;
4196                 }
4197
4198                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
4199                 blocksize = btrfs_level_size(root, *level - 1);
4200                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
4201
4202                 next = read_tree_block(root, bytenr, blocksize, ptr_gen);
4203                 btrfs_tree_lock(next);
4204                 btrfs_set_lock_blocking(next);
4205
4206                 ret = btrfs_lookup_extent_ref(trans, root, bytenr, blocksize,
4207                                               &refs);
4208                 BUG_ON(ret);
4209                 if (refs > 1) {
4210                         parent = path->nodes[*level];
4211                         ret = btrfs_free_extent(trans, root, bytenr,
4212                                         blocksize, parent->start,
4213                                         btrfs_header_owner(parent),
4214                                         btrfs_header_generation(parent),
4215                                         *level - 1, 1);
4216                         BUG_ON(ret);
4217                         path->slots[*level]++;
4218                         btrfs_tree_unlock(next);
4219                         free_extent_buffer(next);
4220                         continue;
4221                 }
4222
4223                 *level = btrfs_header_level(next);
4224                 path->nodes[*level] = next;
4225                 path->slots[*level] = 0;
4226                 path->locks[*level] = 1;
4227                 cond_resched();
4228         }
4229 out:
4230         parent = path->nodes[*level + 1];
4231         bytenr = path->nodes[*level]->start;
4232         blocksize = path->nodes[*level]->len;
4233
4234         ret = btrfs_free_extent(trans, root, bytenr, blocksize,
4235                         parent->start, btrfs_header_owner(parent),
4236                         btrfs_header_generation(parent), *level, 1);
4237         BUG_ON(ret);
4238
4239         if (path->locks[*level]) {
4240                 btrfs_tree_unlock(path->nodes[*level]);
4241                 path->locks[*level] = 0;
4242         }
4243         free_extent_buffer(path->nodes[*level]);
4244         path->nodes[*level] = NULL;
4245         *level += 1;
4246         cond_resched();
4247         return 0;
4248 }
4249
4250 /*
4251  * helper for dropping snapshots.  This walks back up the tree in the path
4252  * to find the first node higher up where we haven't yet gone through
4253  * all the slots
4254  */
4255 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
4256                                  struct btrfs_root *root,
4257                                  struct btrfs_path *path,
4258                                  int *level, int max_level)
4259 {
4260         u64 root_owner;
4261         u64 root_gen;
4262         struct btrfs_root_item *root_item = &root->root_item;
4263         int i;
4264         int slot;
4265         int ret;
4266
4267         for (i = *level; i < max_level && path->nodes[i]; i++) {
4268                 slot = path->slots[i];
4269                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
4270                         struct extent_buffer *node;
4271                         struct btrfs_disk_key disk_key;
4272
4273                         /*
4274                          * there is more work to do in this level.
4275                          * Update the drop_progress marker to reflect
4276                          * the work we've done so far, and then bump
4277                          * the slot number
4278                          */
4279                         node = path->nodes[i];
4280                         path->slots[i]++;
4281                         *level = i;
4282                         WARN_ON(*level == 0);
4283                         btrfs_node_key(node, &disk_key, path->slots[i]);
4284                         memcpy(&root_item->drop_progress,
4285                                &disk_key, sizeof(disk_key));
4286                         root_item->drop_level = i;
4287                         return 0;
4288                 } else {
4289                         struct extent_buffer *parent;
4290
4291                         /*
4292                          * this whole node is done, free our reference
4293                          * on it and go up one level
4294                          */
4295                         if (path->nodes[*level] == root->node)
4296                                 parent = path->nodes[*level];
4297                         else
4298                                 parent = path->nodes[*level + 1];
4299
4300                         root_owner = btrfs_header_owner(parent);
4301                         root_gen = btrfs_header_generation(parent);
4302
4303                         clean_tree_block(trans, root, path->nodes[*level]);
4304                         ret = btrfs_free_extent(trans, root,
4305                                                 path->nodes[*level]->start,
4306                                                 path->nodes[*level]->len,
4307                                                 parent->start, root_owner,
4308                                                 root_gen, *level, 1);
4309                         BUG_ON(ret);
4310                         if (path->locks[*level]) {
4311                                 btrfs_tree_unlock(path->nodes[*level]);
4312                                 path->locks[*level] = 0;
4313                         }
4314                         free_extent_buffer(path->nodes[*level]);
4315                         path->nodes[*level] = NULL;
4316                         *level = i + 1;
4317                 }
4318         }
4319         return 1;
4320 }
4321
4322 /*
4323  * drop the reference count on the tree rooted at 'snap'.  This traverses
4324  * the tree freeing any blocks that have a ref count of zero after being
4325  * decremented.
4326  */
4327 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
4328                         *root)
4329 {
4330         int ret = 0;
4331         int wret;
4332         int level;
4333         struct btrfs_path *path;
4334         int i;
4335         int orig_level;
4336         struct btrfs_root_item *root_item = &root->root_item;
4337
4338         WARN_ON(!mutex_is_locked(&root->fs_info->drop_mutex));
4339         path = btrfs_alloc_path();
4340         BUG_ON(!path);
4341
4342         level = btrfs_header_level(root->node);
4343         orig_level = level;
4344         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
4345                 path->nodes[level] = root->node;
4346                 extent_buffer_get(root->node);
4347                 path->slots[level] = 0;
4348         } else {
4349                 struct btrfs_key key;
4350                 struct btrfs_disk_key found_key;
4351                 struct extent_buffer *node;
4352
4353                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
4354                 level = root_item->drop_level;
4355                 path->lowest_level = level;
4356                 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4357                 if (wret < 0) {
4358                         ret = wret;
4359                         goto out;
4360                 }
4361                 node = path->nodes[level];
4362                 btrfs_node_key(node, &found_key, path->slots[level]);
4363                 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
4364                                sizeof(found_key)));
4365                 /*
4366                  * unlock our path, this is safe because only this
4367                  * function is allowed to delete this snapshot
4368                  */
4369                 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
4370                         if (path->nodes[i] && path->locks[i]) {
4371                                 path->locks[i] = 0;
4372                                 btrfs_tree_unlock(path->nodes[i]);
4373                         }
4374                 }
4375         }
4376         while (1) {
4377                 wret = walk_down_tree(trans, root, path, &level);
4378                 if (wret > 0)
4379                         break;
4380                 if (wret < 0)
4381                         ret = wret;
4382
4383                 wret = walk_up_tree(trans, root, path, &level,
4384                                     BTRFS_MAX_LEVEL);
4385                 if (wret > 0)
4386                         break;
4387                 if (wret < 0)
4388                         ret = wret;
4389                 if (trans->transaction->in_commit) {
4390                         ret = -EAGAIN;
4391                         break;
4392                 }
4393                 atomic_inc(&root->fs_info->throttle_gen);
4394                 wake_up(&root->fs_info->transaction_throttle);
4395         }
4396         for (i = 0; i <= orig_level; i++) {
4397                 if (path->nodes[i]) {
4398                         free_extent_buffer(path->nodes[i]);
4399                         path->nodes[i] = NULL;
4400                 }
4401         }
4402 out:
4403         btrfs_free_path(path);
4404         return ret;
4405 }
4406
4407 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
4408                         struct btrfs_root *root,
4409                         struct extent_buffer *node,
4410                         struct extent_buffer *parent)
4411 {
4412         struct btrfs_path *path;
4413         int level;
4414         int parent_level;
4415         int ret = 0;
4416         int wret;
4417
4418         path = btrfs_alloc_path();
4419         BUG_ON(!path);
4420
4421         btrfs_assert_tree_locked(parent);
4422         parent_level = btrfs_header_level(parent);
4423         extent_buffer_get(parent);
4424         path->nodes[parent_level] = parent;
4425         path->slots[parent_level] = btrfs_header_nritems(parent);
4426
4427         btrfs_assert_tree_locked(node);
4428         level = btrfs_header_level(node);
4429         extent_buffer_get(node);
4430         path->nodes[level] = node;
4431         path->slots[level] = 0;
4432
4433         while (1) {
4434                 wret = walk_down_subtree(trans, root, path, &level);
4435                 if (wret < 0)
4436                         ret = wret;
4437                 if (wret != 0)
4438                         break;
4439
4440                 wret = walk_up_tree(trans, root, path, &level, parent_level);
4441                 if (wret < 0)
4442                         ret = wret;
4443                 if (wret != 0)
4444                         break;
4445         }
4446
4447         btrfs_free_path(path);
4448         return ret;
4449 }
4450
4451 static unsigned long calc_ra(unsigned long start, unsigned long last,
4452                              unsigned long nr)
4453 {
4454         return min(last, start + nr - 1);
4455 }
4456
4457 static noinline int relocate_inode_pages(struct inode *inode, u64 start,
4458                                          u64 len)
4459 {
4460         u64 page_start;
4461         u64 page_end;
4462         unsigned long first_index;
4463         unsigned long last_index;
4464         unsigned long i;
4465         struct page *page;
4466         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4467         struct file_ra_state *ra;
4468         struct btrfs_ordered_extent *ordered;
4469         unsigned int total_read = 0;
4470         unsigned int total_dirty = 0;
4471         int ret = 0;
4472
4473         ra = kzalloc(sizeof(*ra), GFP_NOFS);
4474
4475         mutex_lock(&inode->i_mutex);
4476         first_index = start >> PAGE_CACHE_SHIFT;
4477         last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
4478
4479         /* make sure the dirty trick played by the caller work */
4480         ret = invalidate_inode_pages2_range(inode->i_mapping,
4481                                             first_index, last_index);
4482         if (ret)
4483                 goto out_unlock;
4484
4485         file_ra_state_init(ra, inode->i_mapping);
4486
4487         for (i = first_index ; i <= last_index; i++) {
4488                 if (total_read % ra->ra_pages == 0) {
4489                         btrfs_force_ra(inode->i_mapping, ra, NULL, i,
4490                                        calc_ra(i, last_index, ra->ra_pages));
4491                 }
4492                 total_read++;
4493 again:
4494                 if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
4495                         BUG_ON(1);
4496                 page = grab_cache_page(inode->i_mapping, i);
4497                 if (!page) {
4498                         ret = -ENOMEM;
4499                         goto out_unlock;
4500                 }
4501                 if (!PageUptodate(page)) {
4502                         btrfs_readpage(NULL, page);
4503                         lock_page(page);
4504                         if (!PageUptodate(page)) {
4505                                 unlock_page(page);
4506                                 page_cache_release(page);
4507                                 ret = -EIO;
4508                                 goto out_unlock;
4509                         }
4510                 }
4511                 wait_on_page_writeback(page);
4512
4513                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
4514                 page_end = page_start + PAGE_CACHE_SIZE - 1;
4515                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
4516
4517                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
4518                 if (ordered) {
4519                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
4520                         unlock_page(page);
4521                         page_cache_release(page);
4522                         btrfs_start_ordered_extent(inode, ordered, 1);
4523                         btrfs_put_ordered_extent(ordered);
4524                         goto again;
4525                 }
4526                 set_page_extent_mapped(page);
4527
4528                 if (i == first_index)
4529                         set_extent_bits(io_tree, page_start, page_end,
4530                                         EXTENT_BOUNDARY, GFP_NOFS);
4531                 btrfs_set_extent_delalloc(inode, page_start, page_end);
4532
4533                 set_page_dirty(page);
4534                 total_dirty++;
4535
4536                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
4537                 unlock_page(page);
4538                 page_cache_release(page);
4539         }
4540
4541 out_unlock:
4542         kfree(ra);
4543         mutex_unlock(&inode->i_mutex);
4544         balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
4545         return ret;
4546 }
4547
4548 static noinline int relocate_data_extent(struct inode *reloc_inode,
4549                                          struct btrfs_key *extent_key,
4550                                          u64 offset)
4551 {
4552         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
4553         struct extent_map_tree *em_tree = &BTRFS_I(reloc_inode)->extent_tree;
4554         struct extent_map *em;
4555         u64 start = extent_key->objectid - offset;
4556         u64 end = start + extent_key->offset - 1;
4557
4558         em = alloc_extent_map(GFP_NOFS);
4559         BUG_ON(!em || IS_ERR(em));
4560
4561         em->start = start;
4562         em->len = extent_key->offset;
4563         em->block_len = extent_key->offset;
4564         em->block_start = extent_key->objectid;
4565         em->bdev = root->fs_info->fs_devices->latest_bdev;
4566         set_bit(EXTENT_FLAG_PINNED, &em->flags);
4567
4568         /* setup extent map to cheat btrfs_readpage */
4569         lock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
4570         while (1) {
4571                 int ret;
4572                 spin_lock(&em_tree->lock);
4573                 ret = add_extent_mapping(em_tree, em);
4574                 spin_unlock(&em_tree->lock);
4575                 if (ret != -EEXIST) {
4576                         free_extent_map(em);
4577                         break;
4578                 }
4579                 btrfs_drop_extent_cache(reloc_inode, start, end, 0);
4580         }
4581         unlock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
4582
4583         return relocate_inode_pages(reloc_inode, start, extent_key->offset);
4584 }
4585
4586 struct btrfs_ref_path {
4587         u64 extent_start;
4588         u64 nodes[BTRFS_MAX_LEVEL];
4589         u64 root_objectid;
4590         u64 root_generation;
4591         u64 owner_objectid;
4592         u32 num_refs;
4593         int lowest_level;
4594         int current_level;
4595         int shared_level;
4596
4597         struct btrfs_key node_keys[BTRFS_MAX_LEVEL];
4598         u64 new_nodes[BTRFS_MAX_LEVEL];
4599 };
4600
4601 struct disk_extent {
4602         u64 ram_bytes;
4603         u64 disk_bytenr;
4604         u64 disk_num_bytes;
4605         u64 offset;
4606         u64 num_bytes;
4607         u8 compression;
4608         u8 encryption;
4609         u16 other_encoding;
4610 };
4611
4612 static int is_cowonly_root(u64 root_objectid)
4613 {
4614         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
4615             root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
4616             root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
4617             root_objectid == BTRFS_DEV_TREE_OBJECTID ||
4618             root_objectid == BTRFS_TREE_LOG_OBJECTID ||
4619             root_objectid == BTRFS_CSUM_TREE_OBJECTID)
4620                 return 1;
4621         return 0;
4622 }
4623
4624 static noinline int __next_ref_path(struct btrfs_trans_handle *trans,
4625                                     struct btrfs_root *extent_root,
4626                                     struct btrfs_ref_path *ref_path,
4627                                     int first_time)
4628 {
4629         struct extent_buffer *leaf;
4630         struct btrfs_path *path;
4631         struct btrfs_extent_ref *ref;
4632         struct btrfs_key key;
4633         struct btrfs_key found_key;
4634         u64 bytenr;
4635         u32 nritems;
4636         int level;
4637         int ret = 1;
4638
4639         path = btrfs_alloc_path();
4640         if (!path)
4641                 return -ENOMEM;
4642
4643         if (first_time) {
4644                 ref_path->lowest_level = -1;
4645                 ref_path->current_level = -1;
4646                 ref_path->shared_level = -1;
4647                 goto walk_up;
4648         }
4649 walk_down:
4650         level = ref_path->current_level - 1;
4651         while (level >= -1) {
4652                 u64 parent;
4653                 if (level < ref_path->lowest_level)
4654                         break;
4655
4656                 if (level >= 0)
4657                         bytenr = ref_path->nodes[level];
4658                 else
4659                         bytenr = ref_path->extent_start;
4660                 BUG_ON(bytenr == 0);
4661
4662                 parent = ref_path->nodes[level + 1];
4663                 ref_path->nodes[level + 1] = 0;
4664                 ref_path->current_level = level;
4665                 BUG_ON(parent == 0);
4666
4667                 key.objectid = bytenr;
4668                 key.offset = parent + 1;
4669                 key.type = BTRFS_EXTENT_REF_KEY;
4670
4671                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
4672                 if (ret < 0)
4673                         goto out;
4674                 BUG_ON(ret == 0);
4675
4676                 leaf = path->nodes[0];
4677                 nritems = btrfs_header_nritems(leaf);
4678                 if (path->slots[0] >= nritems) {
4679                         ret = btrfs_next_leaf(extent_root, path);
4680                         if (ret < 0)
4681                                 goto out;
4682                         if (ret > 0)
4683                                 goto next;
4684                         leaf = path->nodes[0];
4685                 }
4686
4687                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4688                 if (found_key.objectid == bytenr &&
4689                     found_key.type == BTRFS_EXTENT_REF_KEY) {
4690                         if (level < ref_path->shared_level)
4691                                 ref_path->shared_level = level;
4692                         goto found;
4693                 }
4694 next:
4695                 level--;
4696                 btrfs_release_path(extent_root, path);
4697                 cond_resched();
4698         }
4699         /* reached lowest level */
4700         ret = 1;
4701         goto out;
4702 walk_up:
4703         level = ref_path->current_level;
4704         while (level < BTRFS_MAX_LEVEL - 1) {
4705                 u64 ref_objectid;
4706
4707                 if (level >= 0)
4708                         bytenr = ref_path->nodes[level];
4709                 else
4710                         bytenr = ref_path->extent_start;
4711
4712                 BUG_ON(bytenr == 0);
4713
4714                 key.objectid = bytenr;
4715                 key.offset = 0;
4716                 key.type = BTRFS_EXTENT_REF_KEY;
4717
4718                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
4719                 if (ret < 0)
4720                         goto out;
4721
4722                 leaf = path->nodes[0];
4723                 nritems = btrfs_header_nritems(leaf);
4724                 if (path->slots[0] >= nritems) {
4725                         ret = btrfs_next_leaf(extent_root, path);
4726                         if (ret < 0)
4727                                 goto out;
4728                         if (ret > 0) {
4729                                 /* the extent was freed by someone */
4730                                 if (ref_path->lowest_level == level)
4731                                         goto out;
4732                                 btrfs_release_path(extent_root, path);
4733                                 goto walk_down;
4734                         }
4735                         leaf = path->nodes[0];
4736                 }
4737
4738                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4739                 if (found_key.objectid != bytenr ||
4740                                 found_key.type != BTRFS_EXTENT_REF_KEY) {
4741                         /* the extent was freed by someone */
4742                         if (ref_path->lowest_level == level) {
4743                                 ret = 1;
4744                                 goto out;
4745                         }
4746                         btrfs_release_path(extent_root, path);
4747                         goto walk_down;
4748                 }
4749 found:
4750                 ref = btrfs_item_ptr(leaf, path->slots[0],
4751                                 struct btrfs_extent_ref);
4752                 ref_objectid = btrfs_ref_objectid(leaf, ref);
4753                 if (ref_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4754                         if (first_time) {
4755                                 level = (int)ref_objectid;
4756                                 BUG_ON(level >= BTRFS_MAX_LEVEL);
4757                                 ref_path->lowest_level = level;
4758                                 ref_path->current_level = level;
4759                                 ref_path->nodes[level] = bytenr;
4760                         } else {
4761                                 WARN_ON(ref_objectid != level);
4762                         }
4763                 } else {
4764                         WARN_ON(level != -1);
4765                 }
4766                 first_time = 0;
4767
4768                 if (ref_path->lowest_level == level) {
4769                         ref_path->owner_objectid = ref_objectid;
4770                         ref_path->num_refs = btrfs_ref_num_refs(leaf, ref);
4771                 }
4772
4773                 /*
4774                  * the block is tree root or the block isn't in reference
4775                  * counted tree.
4776                  */
4777                 if (found_key.objectid == found_key.offset ||
4778                     is_cowonly_root(btrfs_ref_root(leaf, ref))) {
4779                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
4780                         ref_path->root_generation =
4781                                 btrfs_ref_generation(leaf, ref);
4782                         if (level < 0) {
4783                                 /* special reference from the tree log */
4784                                 ref_path->nodes[0] = found_key.offset;
4785                                 ref_path->current_level = 0;
4786                         }
4787                         ret = 0;
4788                         goto out;
4789                 }
4790
4791                 level++;
4792                 BUG_ON(ref_path->nodes[level] != 0);
4793                 ref_path->nodes[level] = found_key.offset;
4794                 ref_path->current_level = level;
4795
4796                 /*
4797                  * the reference was created in the running transaction,
4798                  * no need to continue walking up.
4799                  */
4800                 if (btrfs_ref_generation(leaf, ref) == trans->transid) {
4801                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
4802                         ref_path->root_generation =
4803                                 btrfs_ref_generation(leaf, ref);
4804                         ret = 0;
4805                         goto out;
4806                 }
4807
4808                 btrfs_release_path(extent_root, path);
4809                 cond_resched();
4810         }
4811         /* reached max tree level, but no tree root found. */
4812         BUG();
4813 out:
4814         btrfs_free_path(path);
4815         return ret;
4816 }
4817
4818 static int btrfs_first_ref_path(struct btrfs_trans_handle *trans,
4819                                 struct btrfs_root *extent_root,
4820                                 struct btrfs_ref_path *ref_path,
4821                                 u64 extent_start)
4822 {
4823         memset(ref_path, 0, sizeof(*ref_path));
4824         ref_path->extent_start = extent_start;
4825
4826         return __next_ref_path(trans, extent_root, ref_path, 1);
4827 }
4828
4829 static int btrfs_next_ref_path(struct btrfs_trans_handle *trans,
4830                                struct btrfs_root *extent_root,
4831                                struct btrfs_ref_path *ref_path)
4832 {
4833         return __next_ref_path(trans, extent_root, ref_path, 0);
4834 }
4835
4836 static noinline int get_new_locations(struct inode *reloc_inode,
4837                                       struct btrfs_key *extent_key,
4838                                       u64 offset, int no_fragment,
4839                                       struct disk_extent **extents,
4840                                       int *nr_extents)
4841 {
4842         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
4843         struct btrfs_path *path;
4844         struct btrfs_file_extent_item *fi;
4845         struct extent_buffer *leaf;
4846         struct disk_extent *exts = *extents;
4847         struct btrfs_key found_key;
4848         u64 cur_pos;
4849         u64 last_byte;
4850         u32 nritems;
4851         int nr = 0;
4852         int max = *nr_extents;
4853         int ret;
4854
4855         WARN_ON(!no_fragment && *extents);
4856         if (!exts) {
4857                 max = 1;
4858                 exts = kmalloc(sizeof(*exts) * max, GFP_NOFS);
4859                 if (!exts)
4860                         return -ENOMEM;
4861         }
4862
4863         path = btrfs_alloc_path();
4864         BUG_ON(!path);
4865
4866         cur_pos = extent_key->objectid - offset;
4867         last_byte = extent_key->objectid + extent_key->offset;
4868         ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
4869                                        cur_pos, 0);
4870         if (ret < 0)
4871                 goto out;
4872         if (ret > 0) {
4873                 ret = -ENOENT;
4874                 goto out;
4875         }
4876
4877         while (1) {
4878                 leaf = path->nodes[0];
4879                 nritems = btrfs_header_nritems(leaf);
4880                 if (path->slots[0] >= nritems) {
4881                         ret = btrfs_next_leaf(root, path);
4882                         if (ret < 0)
4883                                 goto out;
4884                         if (ret > 0)
4885                                 break;
4886                         leaf = path->nodes[0];
4887                 }
4888
4889                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4890                 if (found_key.offset != cur_pos ||
4891                     found_key.type != BTRFS_EXTENT_DATA_KEY ||
4892                     found_key.objectid != reloc_inode->i_ino)
4893                         break;
4894
4895                 fi = btrfs_item_ptr(leaf, path->slots[0],
4896                                     struct btrfs_file_extent_item);
4897                 if (btrfs_file_extent_type(leaf, fi) !=
4898                     BTRFS_FILE_EXTENT_REG ||
4899                     btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
4900                         break;
4901
4902                 if (nr == max) {
4903                         struct disk_extent *old = exts;
4904                         max *= 2;
4905                         exts = kzalloc(sizeof(*exts) * max, GFP_NOFS);
4906                         memcpy(exts, old, sizeof(*exts) * nr);
4907                         if (old != *extents)
4908                                 kfree(old);
4909                 }
4910
4911                 exts[nr].disk_bytenr =
4912                         btrfs_file_extent_disk_bytenr(leaf, fi);
4913                 exts[nr].disk_num_bytes =
4914                         btrfs_file_extent_disk_num_bytes(leaf, fi);
4915                 exts[nr].offset = btrfs_file_extent_offset(leaf, fi);
4916                 exts[nr].num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
4917                 exts[nr].ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
4918                 exts[nr].compression = btrfs_file_extent_compression(leaf, fi);
4919                 exts[nr].encryption = btrfs_file_extent_encryption(leaf, fi);
4920                 exts[nr].other_encoding = btrfs_file_extent_other_encoding(leaf,
4921                                                                            fi);
4922                 BUG_ON(exts[nr].offset > 0);
4923                 BUG_ON(exts[nr].compression || exts[nr].encryption);
4924                 BUG_ON(exts[nr].num_bytes != exts[nr].disk_num_bytes);
4925
4926                 cur_pos += exts[nr].num_bytes;
4927                 nr++;
4928
4929                 if (cur_pos + offset >= last_byte)
4930                         break;
4931
4932                 if (no_fragment) {
4933                         ret = 1;
4934                         goto out;
4935                 }
4936                 path->slots[0]++;
4937         }
4938
4939         BUG_ON(cur_pos + offset > last_byte);
4940         if (cur_pos + offset < last_byte) {
4941                 ret = -ENOENT;
4942                 goto out;
4943         }
4944         ret = 0;
4945 out:
4946         btrfs_free_path(path);
4947         if (ret) {
4948                 if (exts != *extents)
4949                         kfree(exts);
4950         } else {
4951                 *extents = exts;
4952                 *nr_extents = nr;
4953         }
4954         return ret;
4955 }
4956
4957 static noinline int replace_one_extent(struct btrfs_trans_handle *trans,
4958                                         struct btrfs_root *root,
4959                                         struct btrfs_path *path,
4960                                         struct btrfs_key *extent_key,
4961                                         struct btrfs_key *leaf_key,
4962                                         struct btrfs_ref_path *ref_path,
4963                                         struct disk_extent *new_extents,
4964                                         int nr_extents)
4965 {
4966         struct extent_buffer *leaf;
4967         struct btrfs_file_extent_item *fi;
4968         struct inode *inode = NULL;
4969         struct btrfs_key key;
4970         u64 lock_start = 0;
4971         u64 lock_end = 0;
4972         u64 num_bytes;
4973         u64 ext_offset;
4974         u64 search_end = (u64)-1;
4975         u32 nritems;
4976         int nr_scaned = 0;
4977         int extent_locked = 0;
4978         int extent_type;
4979         int ret;
4980
4981         memcpy(&key, leaf_key, sizeof(key));
4982         if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
4983                 if (key.objectid < ref_path->owner_objectid ||
4984                     (key.objectid == ref_path->owner_objectid &&
4985                      key.type < BTRFS_EXTENT_DATA_KEY)) {
4986                         key.objectid = ref_path->owner_objectid;
4987                         key.type = BTRFS_EXTENT_DATA_KEY;
4988                         key.offset = 0;
4989                 }
4990         }
4991
4992         while (1) {
4993                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
4994                 if (ret < 0)
4995                         goto out;
4996
4997                 leaf = path->nodes[0];
4998                 nritems = btrfs_header_nritems(leaf);
4999 next:
5000                 if (extent_locked && ret > 0) {
5001                         /*
5002                          * the file extent item was modified by someone
5003                          * before the extent got locked.
5004                          */
5005                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
5006                                       lock_end, GFP_NOFS);
5007                         extent_locked = 0;
5008                 }
5009
5010                 if (path->slots[0] >= nritems) {
5011                         if (++nr_scaned > 2)
5012                                 break;
5013
5014                         BUG_ON(extent_locked);
5015                         ret = btrfs_next_leaf(root, path);
5016                         if (ret < 0)
5017                                 goto out;
5018                         if (ret > 0)
5019                                 break;
5020                         leaf = path->nodes[0];
5021                         nritems = btrfs_header_nritems(leaf);
5022                 }
5023
5024                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
5025
5026                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
5027                         if ((key.objectid > ref_path->owner_objectid) ||
5028                             (key.objectid == ref_path->owner_objectid &&
5029                              key.type > BTRFS_EXTENT_DATA_KEY) ||
5030                             key.offset >= search_end)
5031                                 break;
5032                 }
5033
5034                 if (inode && key.objectid != inode->i_ino) {
5035                         BUG_ON(extent_locked);
5036                         btrfs_release_path(root, path);
5037                         mutex_unlock(&inode->i_mutex);
5038                         iput(inode);
5039                         inode = NULL;
5040                         continue;
5041                 }
5042
5043                 if (key.type != BTRFS_EXTENT_DATA_KEY) {
5044                         path->slots[0]++;
5045                         ret = 1;
5046                         goto next;
5047                 }
5048                 fi = btrfs_item_ptr(leaf, path->slots[0],
5049                                     struct btrfs_file_extent_item);
5050                 extent_type = btrfs_file_extent_type(leaf, fi);
5051                 if ((extent_type != BTRFS_FILE_EXTENT_REG &&
5052                      extent_type != BTRFS_FILE_EXTENT_PREALLOC) ||
5053                     (btrfs_file_extent_disk_bytenr(leaf, fi) !=
5054                      extent_key->objectid)) {
5055                         path->slots[0]++;
5056                         ret = 1;
5057                         goto next;
5058                 }
5059
5060                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
5061                 ext_offset = btrfs_file_extent_offset(leaf, fi);
5062
5063                 if (search_end == (u64)-1) {
5064                         search_end = key.offset - ext_offset +
5065                                 btrfs_file_extent_ram_bytes(leaf, fi);
5066                 }
5067
5068                 if (!extent_locked) {
5069                         lock_start = key.offset;
5070                         lock_end = lock_start + num_bytes - 1;
5071                 } else {
5072                         if (lock_start > key.offset ||
5073                             lock_end + 1 < key.offset + num_bytes) {
5074                                 unlock_extent(&BTRFS_I(inode)->io_tree,
5075                                               lock_start, lock_end, GFP_NOFS);
5076                                 extent_locked = 0;
5077                         }
5078                 }
5079
5080                 if (!inode) {
5081                         btrfs_release_path(root, path);
5082
5083                         inode = btrfs_iget_locked(root->fs_info->sb,
5084                                                   key.objectid, root);
5085                         if (inode->i_state & I_NEW) {
5086                                 BTRFS_I(inode)->root = root;
5087                                 BTRFS_I(inode)->location.objectid =
5088                                         key.objectid;
5089                                 BTRFS_I(inode)->location.type =
5090                                         BTRFS_INODE_ITEM_KEY;
5091                                 BTRFS_I(inode)->location.offset = 0;
5092                                 btrfs_read_locked_inode(inode);
5093                                 unlock_new_inode(inode);
5094                         }
5095                         /*
5096                          * some code call btrfs_commit_transaction while
5097                          * holding the i_mutex, so we can't use mutex_lock
5098                          * here.
5099                          */
5100                         if (is_bad_inode(inode) ||
5101                             !mutex_trylock(&inode->i_mutex)) {
5102                                 iput(inode);
5103                                 inode = NULL;
5104                                 key.offset = (u64)-1;
5105                                 goto skip;
5106                         }
5107                 }
5108
5109                 if (!extent_locked) {
5110                         struct btrfs_ordered_extent *ordered;
5111
5112                         btrfs_release_path(root, path);
5113
5114                         lock_extent(&BTRFS_I(inode)->io_tree, lock_start,
5115                                     lock_end, GFP_NOFS);
5116                         ordered = btrfs_lookup_first_ordered_extent(inode,
5117                                                                     lock_end);
5118                         if (ordered &&
5119                             ordered->file_offset <= lock_end &&
5120                             ordered->file_offset + ordered->len > lock_start) {
5121                                 unlock_extent(&BTRFS_I(inode)->io_tree,
5122                                               lock_start, lock_end, GFP_NOFS);
5123                                 btrfs_start_ordered_extent(inode, ordered, 1);
5124                                 btrfs_put_ordered_extent(ordered);
5125                                 key.offset += num_bytes;
5126                                 goto skip;
5127                         }
5128                         if (ordered)
5129                                 btrfs_put_ordered_extent(ordered);
5130
5131                         extent_locked = 1;
5132                         continue;
5133                 }
5134
5135                 if (nr_extents == 1) {
5136                         /* update extent pointer in place */
5137                         btrfs_set_file_extent_disk_bytenr(leaf, fi,
5138                                                 new_extents[0].disk_bytenr);
5139                         btrfs_set_file_extent_disk_num_bytes(leaf, fi,
5140                                                 new_extents[0].disk_num_bytes);
5141                         btrfs_mark_buffer_dirty(leaf);
5142
5143                         btrfs_drop_extent_cache(inode, key.offset,
5144                                                 key.offset + num_bytes - 1, 0);
5145
5146                         ret = btrfs_inc_extent_ref(trans, root,
5147                                                 new_extents[0].disk_bytenr,
5148                                                 new_extents[0].disk_num_bytes,
5149                                                 leaf->start,
5150                                                 root->root_key.objectid,
5151                                                 trans->transid,
5152                                                 key.objectid);
5153                         BUG_ON(ret);
5154
5155                         ret = btrfs_free_extent(trans, root,
5156                                                 extent_key->objectid,
5157                                                 extent_key->offset,
5158                                                 leaf->start,
5159                                                 btrfs_header_owner(leaf),
5160                                                 btrfs_header_generation(leaf),
5161                                                 key.objectid, 0);
5162                         BUG_ON(ret);
5163
5164                         btrfs_release_path(root, path);
5165                         key.offset += num_bytes;
5166                 } else {
5167                         BUG_ON(1);
5168 #if 0
5169                         u64 alloc_hint;
5170                         u64 extent_len;
5171                         int i;
5172                         /*
5173                          * drop old extent pointer at first, then insert the
5174                          * new pointers one bye one
5175                          */
5176                         btrfs_release_path(root, path);
5177                         ret = btrfs_drop_extents(trans, root, inode, key.offset,
5178                                                  key.offset + num_bytes,
5179                                                  key.offset, &alloc_hint);
5180                         BUG_ON(ret);
5181
5182                         for (i = 0; i < nr_extents; i++) {
5183                                 if (ext_offset >= new_extents[i].num_bytes) {
5184                                         ext_offset -= new_extents[i].num_bytes;
5185                                         continue;
5186                                 }
5187                                 extent_len = min(new_extents[i].num_bytes -
5188                                                  ext_offset, num_bytes);
5189
5190                                 ret = btrfs_insert_empty_item(trans, root,
5191                                                               path, &key,
5192                                                               sizeof(*fi));
5193                                 BUG_ON(ret);
5194
5195                                 leaf = path->nodes[0];
5196                                 fi = btrfs_item_ptr(leaf, path->slots[0],
5197                                                 struct btrfs_file_extent_item);
5198                                 btrfs_set_file_extent_generation(leaf, fi,
5199                                                         trans->transid);
5200                                 btrfs_set_file_extent_type(leaf, fi,
5201                                                         BTRFS_FILE_EXTENT_REG);
5202                                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
5203                                                 new_extents[i].disk_bytenr);
5204                                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
5205                                                 new_extents[i].disk_num_bytes);
5206                                 btrfs_set_file_extent_ram_bytes(leaf, fi,
5207                                                 new_extents[i].ram_bytes);
5208
5209                                 btrfs_set_file_extent_compression(leaf, fi,
5210                                                 new_extents[i].compression);
5211                                 btrfs_set_file_extent_encryption(leaf, fi,
5212                                                 new_extents[i].encryption);
5213                                 btrfs_set_file_extent_other_encoding(leaf, fi,
5214                                                 new_extents[i].other_encoding);
5215
5216                                 btrfs_set_file_extent_num_bytes(leaf, fi,
5217                                                         extent_len);
5218                                 ext_offset += new_extents[i].offset;
5219                                 btrfs_set_file_extent_offset(leaf, fi,
5220                                                         ext_offset);
5221                                 btrfs_mark_buffer_dirty(leaf);
5222
5223                                 btrfs_drop_extent_cache(inode, key.offset,
5224                                                 key.offset + extent_len - 1, 0);
5225
5226                                 ret = btrfs_inc_extent_ref(trans, root,
5227                                                 new_extents[i].disk_bytenr,
5228                                                 new_extents[i].disk_num_bytes,
5229                                                 leaf->start,
5230                                                 root->root_key.objectid,
5231                                                 trans->transid, key.objectid);
5232                                 BUG_ON(ret);
5233                                 btrfs_release_path(root, path);
5234
5235                                 inode_add_bytes(inode, extent_len);
5236
5237                                 ext_offset = 0;
5238                                 num_bytes -= extent_len;
5239                                 key.offset += extent_len;
5240
5241                                 if (num_bytes == 0)
5242                                         break;
5243                         }
5244                         BUG_ON(i >= nr_extents);
5245 #endif
5246                 }
5247
5248                 if (extent_locked) {
5249                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
5250                                       lock_end, GFP_NOFS);
5251                         extent_locked = 0;
5252                 }
5253 skip:
5254                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS &&
5255                     key.offset >= search_end)
5256                         break;
5257
5258                 cond_resched();
5259         }
5260         ret = 0;
5261 out:
5262         btrfs_release_path(root, path);
5263         if (inode) {
5264                 mutex_unlock(&inode->i_mutex);
5265                 if (extent_locked) {
5266                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
5267                                       lock_end, GFP_NOFS);
5268                 }
5269                 iput(inode);
5270         }
5271         return ret;
5272 }
5273
5274 int btrfs_reloc_tree_cache_ref(struct btrfs_trans_handle *trans,
5275                                struct btrfs_root *root,
5276                                struct extent_buffer *buf, u64 orig_start)
5277 {
5278         int level;
5279         int ret;
5280
5281         BUG_ON(btrfs_header_generation(buf) != trans->transid);
5282         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
5283
5284         level = btrfs_header_level(buf);
5285         if (level == 0) {
5286                 struct btrfs_leaf_ref *ref;
5287                 struct btrfs_leaf_ref *orig_ref;
5288
5289                 orig_ref = btrfs_lookup_leaf_ref(root, orig_start);
5290                 if (!orig_ref)
5291                         return -ENOENT;
5292
5293                 ref = btrfs_alloc_leaf_ref(root, orig_ref->nritems);
5294                 if (!ref) {
5295                         btrfs_free_leaf_ref(root, orig_ref);
5296                         return -ENOMEM;
5297                 }
5298
5299                 ref->nritems = orig_ref->nritems;
5300                 memcpy(ref->extents, orig_ref->extents,
5301                         sizeof(ref->extents[0]) * ref->nritems);
5302
5303                 btrfs_free_leaf_ref(root, orig_ref);
5304
5305                 ref->root_gen = trans->transid;
5306                 ref->bytenr = buf->start;
5307                 ref->owner = btrfs_header_owner(buf);
5308                 ref->generation = btrfs_header_generation(buf);
5309
5310                 ret = btrfs_add_leaf_ref(root, ref, 0);
5311                 WARN_ON(ret);
5312                 btrfs_free_leaf_ref(root, ref);
5313         }
5314         return 0;
5315 }
5316
5317 static noinline int invalidate_extent_cache(struct btrfs_root *root,
5318                                         struct extent_buffer *leaf,
5319                                         struct btrfs_block_group_cache *group,
5320                                         struct btrfs_root *target_root)
5321 {
5322         struct btrfs_key key;
5323         struct inode *inode = NULL;
5324         struct btrfs_file_extent_item *fi;
5325         u64 num_bytes;
5326         u64 skip_objectid = 0;
5327         u32 nritems;
5328         u32 i;
5329
5330         nritems = btrfs_header_nritems(leaf);
5331         for (i = 0; i < nritems; i++) {
5332                 btrfs_item_key_to_cpu(leaf, &key, i);
5333                 if (key.objectid == skip_objectid ||
5334                     key.type != BTRFS_EXTENT_DATA_KEY)
5335                         continue;
5336                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
5337                 if (btrfs_file_extent_type(leaf, fi) ==
5338                     BTRFS_FILE_EXTENT_INLINE)
5339                         continue;
5340                 if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
5341                         continue;
5342                 if (!inode || inode->i_ino != key.objectid) {
5343                         iput(inode);
5344                         inode = btrfs_ilookup(target_root->fs_info->sb,
5345                                               key.objectid, target_root, 1);
5346                 }
5347                 if (!inode) {
5348                         skip_objectid = key.objectid;
5349                         continue;
5350                 }
5351                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
5352
5353                 lock_extent(&BTRFS_I(inode)->io_tree, key.offset,
5354                             key.offset + num_bytes - 1, GFP_NOFS);
5355                 btrfs_drop_extent_cache(inode, key.offset,
5356                                         key.offset + num_bytes - 1, 1);
5357                 unlock_extent(&BTRFS_I(inode)->io_tree, key.offset,
5358                               key.offset + num_bytes - 1, GFP_NOFS);
5359                 cond_resched();
5360         }
5361         iput(inode);
5362         return 0;
5363 }
5364
5365 static noinline int replace_extents_in_leaf(struct btrfs_trans_handle *trans,
5366                                         struct btrfs_root *root,
5367                                         struct extent_buffer *leaf,
5368                                         struct btrfs_block_group_cache *group,
5369                                         struct inode *reloc_inode)
5370 {
5371         struct btrfs_key key;
5372         struct btrfs_key extent_key;
5373         struct btrfs_file_extent_item *fi;
5374         struct btrfs_leaf_ref *ref;
5375         struct disk_extent *new_extent;
5376         u64 bytenr;
5377         u64 num_bytes;
5378         u32 nritems;
5379         u32 i;
5380         int ext_index;
5381         int nr_extent;
5382         int ret;
5383
5384         new_extent = kmalloc(sizeof(*new_extent), GFP_NOFS);
5385         BUG_ON(!new_extent);
5386
5387         ref = btrfs_lookup_leaf_ref(root, leaf->start);
5388         BUG_ON(!ref);
5389
5390         ext_index = -1;
5391         nritems = btrfs_header_nritems(leaf);
5392         for (i = 0; i < nritems; i++) {
5393                 btrfs_item_key_to_cpu(leaf, &key, i);
5394                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
5395                         continue;
5396                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
5397                 if (btrfs_file_extent_type(leaf, fi) ==
5398                     BTRFS_FILE_EXTENT_INLINE)
5399                         continue;
5400                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
5401                 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
5402                 if (bytenr == 0)
5403                         continue;
5404
5405                 ext_index++;
5406                 if (bytenr >= group->key.objectid + group->key.offset ||
5407                     bytenr + num_bytes <= group->key.objectid)
5408                         continue;
5409
5410                 extent_key.objectid = bytenr;
5411                 extent_key.offset = num_bytes;
5412                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
5413                 nr_extent = 1;
5414                 ret = get_new_locations(reloc_inode, &extent_key,
5415                                         group->key.objectid, 1,
5416                                         &new_extent, &nr_extent);
5417                 if (ret > 0)
5418                         continue;
5419                 BUG_ON(ret < 0);
5420
5421                 BUG_ON(ref->extents[ext_index].bytenr != bytenr);
5422                 BUG_ON(ref->extents[ext_index].num_bytes != num_bytes);
5423                 ref->extents[ext_index].bytenr = new_extent->disk_bytenr;
5424                 ref->extents[ext_index].num_bytes = new_extent->disk_num_bytes;
5425
5426                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
5427                                                 new_extent->disk_bytenr);
5428                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
5429                                                 new_extent->disk_num_bytes);
5430                 btrfs_mark_buffer_dirty(leaf);
5431
5432                 ret = btrfs_inc_extent_ref(trans, root,
5433                                         new_extent->disk_bytenr,
5434                                         new_extent->disk_num_bytes,
5435                                         leaf->start,
5436                                         root->root_key.objectid,
5437                                         trans->transid, key.objectid);
5438                 BUG_ON(ret);
5439                 ret = btrfs_free_extent(trans, root,
5440                                         bytenr, num_bytes, leaf->start,
5441                                         btrfs_header_owner(leaf),
5442                                         btrfs_header_generation(leaf),
5443                                         key.objectid, 0);
5444                 BUG_ON(ret);
5445                 cond_resched();
5446         }
5447         kfree(new_extent);
5448         BUG_ON(ext_index + 1 != ref->nritems);
5449         btrfs_free_leaf_ref(root, ref);
5450         return 0;
5451 }
5452
5453 int btrfs_free_reloc_root(struct btrfs_trans_handle *trans,
5454                           struct btrfs_root *root)
5455 {
5456         struct btrfs_root *reloc_root;
5457         int ret;
5458
5459         if (root->reloc_root) {
5460                 reloc_root = root->reloc_root;
5461                 root->reloc_root = NULL;
5462                 list_add(&reloc_root->dead_list,
5463                          &root->fs_info->dead_reloc_roots);
5464
5465                 btrfs_set_root_bytenr(&reloc_root->root_item,
5466                                       reloc_root->node->start);
5467                 btrfs_set_root_level(&root->root_item,
5468                                      btrfs_header_level(reloc_root->node));
5469                 memset(&reloc_root->root_item.drop_progress, 0,
5470                         sizeof(struct btrfs_disk_key));
5471                 reloc_root->root_item.drop_level = 0;
5472
5473                 ret = btrfs_update_root(trans, root->fs_info->tree_root,
5474                                         &reloc_root->root_key,
5475                                         &reloc_root->root_item);
5476                 BUG_ON(ret);
5477         }
5478         return 0;
5479 }
5480
5481 int btrfs_drop_dead_reloc_roots(struct btrfs_root *root)
5482 {
5483         struct btrfs_trans_handle *trans;
5484         struct btrfs_root *reloc_root;
5485         struct btrfs_root *prev_root = NULL;
5486         struct list_head dead_roots;
5487         int ret;
5488         unsigned long nr;
5489
5490         INIT_LIST_HEAD(&dead_roots);
5491         list_splice_init(&root->fs_info->dead_reloc_roots, &dead_roots);
5492
5493         while (!list_empty(&dead_roots)) {
5494                 reloc_root = list_entry(dead_roots.prev,
5495                                         struct btrfs_root, dead_list);
5496                 list_del_init(&reloc_root->dead_list);
5497
5498                 BUG_ON(reloc_root->commit_root != NULL);
5499                 while (1) {
5500                         trans = btrfs_join_transaction(root, 1);
5501                         BUG_ON(!trans);
5502
5503                         mutex_lock(&root->fs_info->drop_mutex);
5504                         ret = btrfs_drop_snapshot(trans, reloc_root);
5505                         if (ret != -EAGAIN)
5506                                 break;
5507                         mutex_unlock(&root->fs_info->drop_mutex);
5508
5509                         nr = trans->blocks_used;
5510                         ret = btrfs_end_transaction(trans, root);
5511                         BUG_ON(ret);
5512                         btrfs_btree_balance_dirty(root, nr);
5513                 }
5514
5515                 free_extent_buffer(reloc_root->node);
5516
5517                 ret = btrfs_del_root(trans, root->fs_info->tree_root,
5518                                      &reloc_root->root_key);
5519                 BUG_ON(ret);
5520                 mutex_unlock(&root->fs_info->drop_mutex);
5521
5522                 nr = trans->blocks_used;
5523                 ret = btrfs_end_transaction(trans, root);
5524                 BUG_ON(ret);
5525                 btrfs_btree_balance_dirty(root, nr);
5526
5527                 kfree(prev_root);
5528                 prev_root = reloc_root;
5529         }
5530         if (prev_root) {
5531                 btrfs_remove_leaf_refs(prev_root, (u64)-1, 0);
5532                 kfree(prev_root);
5533         }
5534         return 0;
5535 }
5536
5537 int btrfs_add_dead_reloc_root(struct btrfs_root *root)
5538 {
5539         list_add(&root->dead_list, &root->fs_info->dead_reloc_roots);
5540         return 0;
5541 }
5542
5543 int btrfs_cleanup_reloc_trees(struct btrfs_root *root)
5544 {
5545         struct btrfs_root *reloc_root;
5546         struct btrfs_trans_handle *trans;
5547         struct btrfs_key location;
5548         int found;
5549         int ret;
5550
5551         mutex_lock(&root->fs_info->tree_reloc_mutex);
5552         ret = btrfs_find_dead_roots(root, BTRFS_TREE_RELOC_OBJECTID, NULL);
5553         BUG_ON(ret);
5554         found = !list_empty(&root->fs_info->dead_reloc_roots);
5555         mutex_unlock(&root->fs_info->tree_reloc_mutex);
5556
5557         if (found) {
5558                 trans = btrfs_start_transaction(root, 1);
5559                 BUG_ON(!trans);
5560                 ret = btrfs_commit_transaction(trans, root);
5561                 BUG_ON(ret);
5562         }
5563
5564         location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
5565         location.offset = (u64)-1;
5566         location.type = BTRFS_ROOT_ITEM_KEY;
5567
5568         reloc_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
5569         BUG_ON(!reloc_root);
5570         btrfs_orphan_cleanup(reloc_root);
5571         return 0;
5572 }
5573
5574 static noinline int init_reloc_tree(struct btrfs_trans_handle *trans,
5575                                     struct btrfs_root *root)
5576 {
5577         struct btrfs_root *reloc_root;
5578         struct extent_buffer *eb;
5579         struct btrfs_root_item *root_item;
5580         struct btrfs_key root_key;
5581         int ret;
5582
5583         BUG_ON(!root->ref_cows);
5584         if (root->reloc_root)
5585                 return 0;
5586
5587         root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
5588         BUG_ON(!root_item);
5589
5590         ret = btrfs_copy_root(trans, root, root->commit_root,
5591                               &eb, BTRFS_TREE_RELOC_OBJECTID);
5592         BUG_ON(ret);
5593
5594         root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
5595         root_key.offset = root->root_key.objectid;
5596         root_key.type = BTRFS_ROOT_ITEM_KEY;
5597
5598         memcpy(root_item, &root->root_item, sizeof(root_item));
5599         btrfs_set_root_refs(root_item, 0);
5600         btrfs_set_root_bytenr(root_item, eb->start);
5601         btrfs_set_root_level(root_item, btrfs_header_level(eb));
5602         btrfs_set_root_generation(root_item, trans->transid);
5603
5604         btrfs_tree_unlock(eb);
5605         free_extent_buffer(eb);
5606
5607         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
5608                                 &root_key, root_item);
5609         BUG_ON(ret);
5610         kfree(root_item);
5611
5612         reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
5613                                                  &root_key);
5614         BUG_ON(!reloc_root);
5615         reloc_root->last_trans = trans->transid;
5616         reloc_root->commit_root = NULL;
5617         reloc_root->ref_tree = &root->fs_info->reloc_ref_tree;
5618
5619         root->reloc_root = reloc_root;
5620         return 0;
5621 }
5622
5623 /*
5624  * Core function of space balance.
5625  *
5626  * The idea is using reloc trees to relocate tree blocks in reference
5627  * counted roots. There is one reloc tree for each subvol, and all
5628  * reloc trees share same root key objectid. Reloc trees are snapshots
5629  * of the latest committed roots of subvols (root->commit_root).
5630  *
5631  * To relocate a tree block referenced by a subvol, there are two steps.
5632  * COW the block through subvol's reloc tree, then update block pointer
5633  * in the subvol to point to the new block. Since all reloc trees share
5634  * same root key objectid, doing special handing for tree blocks owned
5635  * by them is easy. Once a tree block has been COWed in one reloc tree,
5636  * we can use the resulting new block directly when the same block is
5637  * required to COW again through other reloc trees. By this way, relocated
5638  * tree blocks are shared between reloc trees, so they are also shared
5639  * between subvols.
5640  */
5641 static noinline int relocate_one_path(struct btrfs_trans_handle *trans,
5642                                       struct btrfs_root *root,
5643                                       struct btrfs_path *path,
5644                                       struct btrfs_key *first_key,
5645                                       struct btrfs_ref_path *ref_path,
5646                                       struct btrfs_block_group_cache *group,
5647                                       struct inode *reloc_inode)
5648 {
5649         struct btrfs_root *reloc_root;
5650         struct extent_buffer *eb = NULL;
5651         struct btrfs_key *keys;
5652         u64 *nodes;
5653         int level;
5654         int shared_level;
5655         int lowest_level = 0;
5656         int ret;
5657
5658         if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
5659                 lowest_level = ref_path->owner_objectid;
5660
5661         if (!root->ref_cows) {
5662                 path->lowest_level = lowest_level;
5663                 ret = btrfs_search_slot(trans, root, first_key, path, 0, 1);
5664                 BUG_ON(ret < 0);
5665                 path->lowest_level = 0;
5666                 btrfs_release_path(root, path);
5667                 return 0;
5668         }
5669
5670         mutex_lock(&root->fs_info->tree_reloc_mutex);
5671         ret = init_reloc_tree(trans, root);
5672         BUG_ON(ret);
5673         reloc_root = root->reloc_root;
5674
5675         shared_level = ref_path->shared_level;
5676         ref_path->shared_level = BTRFS_MAX_LEVEL - 1;
5677
5678         keys = ref_path->node_keys;
5679         nodes = ref_path->new_nodes;
5680         memset(&keys[shared_level + 1], 0,
5681                sizeof(*keys) * (BTRFS_MAX_LEVEL - shared_level - 1));
5682         memset(&nodes[shared_level + 1], 0,
5683                sizeof(*nodes) * (BTRFS_MAX_LEVEL - shared_level - 1));
5684
5685         if (nodes[lowest_level] == 0) {
5686                 path->lowest_level = lowest_level;
5687                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
5688                                         0, 1);
5689                 BUG_ON(ret);
5690                 for (level = lowest_level; level < BTRFS_MAX_LEVEL; level++) {
5691                         eb = path->nodes[level];
5692                         if (!eb || eb == reloc_root->node)
5693                                 break;
5694                         nodes[level] = eb->start;
5695                         if (level == 0)
5696                                 btrfs_item_key_to_cpu(eb, &keys[level], 0);
5697                         else
5698                                 btrfs_node_key_to_cpu(eb, &keys[level], 0);
5699                 }
5700                 if (nodes[0] &&
5701                     ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5702                         eb = path->nodes[0];
5703                         ret = replace_extents_in_leaf(trans, reloc_root, eb,
5704                                                       group, reloc_inode);
5705                         BUG_ON(ret);
5706                 }
5707                 btrfs_release_path(reloc_root, path);
5708         } else {
5709                 ret = btrfs_merge_path(trans, reloc_root, keys, nodes,
5710                                        lowest_level);
5711                 BUG_ON(ret);
5712         }
5713
5714         /*
5715          * replace tree blocks in the fs tree with tree blocks in
5716          * the reloc tree.
5717          */
5718         ret = btrfs_merge_path(trans, root, keys, nodes, lowest_level);
5719         BUG_ON(ret < 0);
5720
5721         if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5722                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
5723                                         0, 0);
5724                 BUG_ON(ret);
5725                 extent_buffer_get(path->nodes[0]);
5726                 eb = path->nodes[0];
5727                 btrfs_release_path(reloc_root, path);
5728                 ret = invalidate_extent_cache(reloc_root, eb, group, root);
5729                 BUG_ON(ret);
5730                 free_extent_buffer(eb);
5731         }
5732
5733         mutex_unlock(&root->fs_info->tree_reloc_mutex);
5734         path->lowest_level = 0;
5735         return 0;
5736 }
5737
5738 static noinline int relocate_tree_block(struct btrfs_trans_handle *trans,
5739                                         struct btrfs_root *root,
5740                                         struct btrfs_path *path,
5741                                         struct btrfs_key *first_key,
5742                                         struct btrfs_ref_path *ref_path)
5743 {
5744         int ret;
5745
5746         ret = relocate_one_path(trans, root, path, first_key,
5747                                 ref_path, NULL, NULL);
5748         BUG_ON(ret);
5749
5750         if (root == root->fs_info->extent_root)
5751                 btrfs_extent_post_op(trans, root);
5752
5753         return 0;
5754 }
5755
5756 static noinline int del_extent_zero(struct btrfs_trans_handle *trans,
5757                                     struct btrfs_root *extent_root,
5758                                     struct btrfs_path *path,
5759                                     struct btrfs_key *extent_key)
5760 {
5761         int ret;
5762
5763         ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
5764         if (ret)
5765                 goto out;
5766         ret = btrfs_del_item(trans, extent_root, path);
5767 out:
5768         btrfs_release_path(extent_root, path);
5769         return ret;
5770 }
5771
5772 static noinline struct btrfs_root *read_ref_root(struct btrfs_fs_info *fs_info,
5773                                                 struct btrfs_ref_path *ref_path)
5774 {
5775         struct btrfs_key root_key;
5776
5777         root_key.objectid = ref_path->root_objectid;
5778         root_key.type = BTRFS_ROOT_ITEM_KEY;
5779         if (is_cowonly_root(ref_path->root_objectid))
5780                 root_key.offset = 0;
5781         else
5782                 root_key.offset = (u64)-1;
5783
5784         return btrfs_read_fs_root_no_name(fs_info, &root_key);
5785 }
5786
5787 static noinline int relocate_one_extent(struct btrfs_root *extent_root,
5788                                         struct btrfs_path *path,
5789                                         struct btrfs_key *extent_key,
5790                                         struct btrfs_block_group_cache *group,
5791                                         struct inode *reloc_inode, int pass)
5792 {
5793         struct btrfs_trans_handle *trans;
5794         struct btrfs_root *found_root;
5795         struct btrfs_ref_path *ref_path = NULL;
5796         struct disk_extent *new_extents = NULL;
5797         int nr_extents = 0;
5798         int loops;
5799         int ret;
5800         int level;
5801         struct btrfs_key first_key;
5802         u64 prev_block = 0;
5803
5804
5805         trans = btrfs_start_transaction(extent_root, 1);
5806         BUG_ON(!trans);
5807
5808         if (extent_key->objectid == 0) {
5809                 ret = del_extent_zero(trans, extent_root, path, extent_key);
5810                 goto out;
5811         }
5812
5813         ref_path = kmalloc(sizeof(*ref_path), GFP_NOFS);
5814         if (!ref_path) {
5815                 ret = -ENOMEM;
5816                 goto out;
5817         }
5818
5819         for (loops = 0; ; loops++) {
5820                 if (loops == 0) {
5821                         ret = btrfs_first_ref_path(trans, extent_root, ref_path,
5822                                                    extent_key->objectid);
5823                 } else {
5824                         ret = btrfs_next_ref_path(trans, extent_root, ref_path);
5825                 }
5826                 if (ret < 0)
5827                         goto out;
5828                 if (ret > 0)
5829                         break;
5830
5831                 if (ref_path->root_objectid == BTRFS_TREE_LOG_OBJECTID ||
5832                     ref_path->root_objectid == BTRFS_TREE_RELOC_OBJECTID)
5833                         continue;
5834
5835                 found_root = read_ref_root(extent_root->fs_info, ref_path);
5836                 BUG_ON(!found_root);
5837                 /*
5838                  * for reference counted tree, only process reference paths
5839                  * rooted at the latest committed root.
5840                  */
5841                 if (found_root->ref_cows &&
5842                     ref_path->root_generation != found_root->root_key.offset)
5843                         continue;
5844
5845                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5846                         if (pass == 0) {
5847                                 /*
5848                                  * copy data extents to new locations
5849                                  */
5850                                 u64 group_start = group->key.objectid;
5851                                 ret = relocate_data_extent(reloc_inode,
5852                                                            extent_key,
5853                                                            group_start);
5854                                 if (ret < 0)
5855                                         goto out;
5856                                 break;
5857                         }
5858                         level = 0;
5859                 } else {
5860                         level = ref_path->owner_objectid;
5861                 }
5862
5863                 if (prev_block != ref_path->nodes[level]) {
5864                         struct extent_buffer *eb;
5865                         u64 block_start = ref_path->nodes[level];
5866                         u64 block_size = btrfs_level_size(found_root, level);
5867
5868                         eb = read_tree_block(found_root, block_start,
5869                                              block_size, 0);
5870                         btrfs_tree_lock(eb);
5871                         BUG_ON(level != btrfs_header_level(eb));
5872
5873                         if (level == 0)
5874                                 btrfs_item_key_to_cpu(eb, &first_key, 0);
5875                         else
5876                                 btrfs_node_key_to_cpu(eb, &first_key, 0);
5877
5878                         btrfs_tree_unlock(eb);
5879                         free_extent_buffer(eb);
5880                         prev_block = block_start;
5881                 }
5882
5883                 mutex_lock(&extent_root->fs_info->trans_mutex);
5884                 btrfs_record_root_in_trans(found_root);
5885                 mutex_unlock(&extent_root->fs_info->trans_mutex);
5886                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5887                         /*
5888                          * try to update data extent references while
5889                          * keeping metadata shared between snapshots.
5890                          */
5891                         if (pass == 1) {
5892                                 ret = relocate_one_path(trans, found_root,
5893                                                 path, &first_key, ref_path,
5894                                                 group, reloc_inode);
5895                                 if (ret < 0)
5896                                         goto out;
5897                                 continue;
5898                         }
5899                         /*
5900                          * use fallback method to process the remaining
5901                          * references.
5902                          */
5903                         if (!new_extents) {
5904                                 u64 group_start = group->key.objectid;
5905                                 new_extents = kmalloc(sizeof(*new_extents),
5906                                                       GFP_NOFS);
5907                                 nr_extents = 1;
5908                                 ret = get_new_locations(reloc_inode,
5909                                                         extent_key,
5910                                                         group_start, 1,
5911                                                         &new_extents,
5912                                                         &nr_extents);
5913                                 if (ret)
5914                                         goto out;
5915                         }
5916                         ret = replace_one_extent(trans, found_root,
5917                                                 path, extent_key,
5918                                                 &first_key, ref_path,
5919                                                 new_extents, nr_extents);
5920                 } else {
5921                         ret = relocate_tree_block(trans, found_root, path,
5922                                                   &first_key, ref_path);
5923                 }
5924                 if (ret < 0)
5925                         goto out;
5926         }
5927         ret = 0;
5928 out:
5929         btrfs_end_transaction(trans, extent_root);
5930         kfree(new_extents);
5931         kfree(ref_path);
5932         return ret;
5933 }
5934
5935 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
5936 {
5937         u64 num_devices;
5938         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
5939                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
5940
5941         num_devices = root->fs_info->fs_devices->rw_devices;
5942         if (num_devices == 1) {
5943                 stripped |= BTRFS_BLOCK_GROUP_DUP;
5944                 stripped = flags & ~stripped;
5945
5946                 /* turn raid0 into single device chunks */
5947                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
5948                         return stripped;
5949
5950                 /* turn mirroring into duplication */
5951                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
5952                              BTRFS_BLOCK_GROUP_RAID10))
5953                         return stripped | BTRFS_BLOCK_GROUP_DUP;
5954                 return flags;
5955         } else {
5956                 /* they already had raid on here, just return */
5957                 if (flags & stripped)
5958                         return flags;
5959
5960                 stripped |= BTRFS_BLOCK_GROUP_DUP;
5961                 stripped = flags & ~stripped;
5962
5963                 /* switch duplicated blocks with raid1 */
5964                 if (flags & BTRFS_BLOCK_GROUP_DUP)
5965                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
5966
5967                 /* turn single device chunks into raid0 */
5968                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
5969         }
5970         return flags;
5971 }
5972
5973 static int __alloc_chunk_for_shrink(struct btrfs_root *root,
5974                      struct btrfs_block_group_cache *shrink_block_group,
5975                      int force)
5976 {
5977         struct btrfs_trans_handle *trans;
5978         u64 new_alloc_flags;
5979         u64 calc;
5980
5981         spin_lock(&shrink_block_group->lock);
5982         if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
5983                 spin_unlock(&shrink_block_group->lock);
5984
5985                 trans = btrfs_start_transaction(root, 1);
5986                 spin_lock(&shrink_block_group->lock);
5987
5988                 new_alloc_flags = update_block_group_flags(root,
5989                                                    shrink_block_group->flags);
5990                 if (new_alloc_flags != shrink_block_group->flags) {
5991                         calc =
5992                              btrfs_block_group_used(&shrink_block_group->item);
5993                 } else {
5994                         calc = shrink_block_group->key.offset;
5995                 }
5996                 spin_unlock(&shrink_block_group->lock);
5997
5998                 do_chunk_alloc(trans, root->fs_info->extent_root,
5999                                calc + 2 * 1024 * 1024, new_alloc_flags, force);
6000
6001                 btrfs_end_transaction(trans, root);
6002         } else
6003                 spin_unlock(&shrink_block_group->lock);
6004         return 0;
6005 }
6006
6007 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
6008                                  struct btrfs_root *root,
6009                                  u64 objectid, u64 size)
6010 {
6011         struct btrfs_path *path;
6012         struct btrfs_inode_item *item;
6013         struct extent_buffer *leaf;
6014         int ret;
6015
6016         path = btrfs_alloc_path();
6017         if (!path)
6018                 return -ENOMEM;
6019
6020         ret = btrfs_insert_empty_inode(trans, root, path, objectid);
6021         if (ret)
6022                 goto out;
6023
6024         leaf = path->nodes[0];
6025         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
6026         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
6027         btrfs_set_inode_generation(leaf, item, 1);
6028         btrfs_set_inode_size(leaf, item, size);
6029         btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
6030         btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS);
6031         btrfs_mark_buffer_dirty(leaf);
6032         btrfs_release_path(root, path);
6033 out:
6034         btrfs_free_path(path);
6035         return ret;
6036 }
6037
6038 static noinline struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
6039                                         struct btrfs_block_group_cache *group)
6040 {
6041         struct inode *inode = NULL;
6042         struct btrfs_trans_handle *trans;
6043         struct btrfs_root *root;
6044         struct btrfs_key root_key;
6045         u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
6046         int err = 0;
6047
6048         root_key.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
6049         root_key.type = BTRFS_ROOT_ITEM_KEY;
6050         root_key.offset = (u64)-1;
6051         root = btrfs_read_fs_root_no_name(fs_info, &root_key);
6052         if (IS_ERR(root))
6053                 return ERR_CAST(root);
6054
6055         trans = btrfs_start_transaction(root, 1);
6056         BUG_ON(!trans);
6057
6058         err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
6059         if (err)
6060                 goto out;
6061
6062         err = __insert_orphan_inode(trans, root, objectid, group->key.offset);
6063         BUG_ON(err);
6064
6065         err = btrfs_insert_file_extent(trans, root, objectid, 0, 0, 0,
6066                                        group->key.offset, 0, group->key.offset,
6067                                        0, 0, 0);
6068         BUG_ON(err);
6069
6070         inode = btrfs_iget_locked(root->fs_info->sb, objectid, root);
6071         if (inode->i_state & I_NEW) {
6072                 BTRFS_I(inode)->root = root;
6073                 BTRFS_I(inode)->location.objectid = objectid;
6074                 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
6075                 BTRFS_I(inode)->location.offset = 0;
6076                 btrfs_read_locked_inode(inode);
6077                 unlock_new_inode(inode);
6078                 BUG_ON(is_bad_inode(inode));
6079         } else {
6080                 BUG_ON(1);
6081         }
6082         BTRFS_I(inode)->index_cnt = group->key.objectid;
6083
6084         err = btrfs_orphan_add(trans, inode);
6085 out:
6086         btrfs_end_transaction(trans, root);
6087         if (err) {
6088                 if (inode)
6089                         iput(inode);
6090                 inode = ERR_PTR(err);
6091         }
6092         return inode;
6093 }
6094
6095 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
6096 {
6097
6098         struct btrfs_ordered_sum *sums;
6099         struct btrfs_sector_sum *sector_sum;
6100         struct btrfs_ordered_extent *ordered;
6101         struct btrfs_root *root = BTRFS_I(inode)->root;
6102         struct list_head list;
6103         size_t offset;
6104         int ret;
6105         u64 disk_bytenr;
6106
6107         INIT_LIST_HEAD(&list);
6108
6109         ordered = btrfs_lookup_ordered_extent(inode, file_pos);
6110         BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
6111
6112         disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
6113         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
6114                                        disk_bytenr + len - 1, &list);
6115
6116         while (!list_empty(&list)) {
6117                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
6118                 list_del_init(&sums->list);
6119
6120                 sector_sum = sums->sums;
6121                 sums->bytenr = ordered->start;
6122
6123                 offset = 0;
6124                 while (offset < sums->len) {
6125                         sector_sum->bytenr += ordered->start - disk_bytenr;
6126                         sector_sum++;
6127                         offset += root->sectorsize;
6128                 }
6129
6130                 btrfs_add_ordered_sum(inode, ordered, sums);
6131         }
6132         btrfs_put_ordered_extent(ordered);
6133         return 0;
6134 }
6135
6136 int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start)
6137 {
6138         struct btrfs_trans_handle *trans;
6139         struct btrfs_path *path;
6140         struct btrfs_fs_info *info = root->fs_info;
6141         struct extent_buffer *leaf;
6142         struct inode *reloc_inode;
6143         struct btrfs_block_group_cache *block_group;
6144         struct btrfs_key key;
6145         u64 skipped;
6146         u64 cur_byte;
6147         u64 total_found;
6148         u32 nritems;
6149         int ret;
6150         int progress;
6151         int pass = 0;
6152
6153         root = root->fs_info->extent_root;
6154
6155         block_group = btrfs_lookup_block_group(info, group_start);
6156         BUG_ON(!block_group);
6157
6158         printk(KERN_INFO "btrfs relocating block group %llu flags %llu\n",
6159                (unsigned long long)block_group->key.objectid,
6160                (unsigned long long)block_group->flags);
6161
6162         path = btrfs_alloc_path();
6163         BUG_ON(!path);
6164
6165         reloc_inode = create_reloc_inode(info, block_group);
6166         BUG_ON(IS_ERR(reloc_inode));
6167
6168         __alloc_chunk_for_shrink(root, block_group, 1);
6169         set_block_group_readonly(block_group);
6170
6171         btrfs_start_delalloc_inodes(info->tree_root);
6172         btrfs_wait_ordered_extents(info->tree_root, 0);
6173 again:
6174         skipped = 0;
6175         total_found = 0;
6176         progress = 0;
6177         key.objectid = block_group->key.objectid;
6178         key.offset = 0;
6179         key.type = 0;
6180         cur_byte = key.objectid;
6181
6182         trans = btrfs_start_transaction(info->tree_root, 1);
6183         btrfs_commit_transaction(trans, info->tree_root);
6184
6185         mutex_lock(&root->fs_info->cleaner_mutex);
6186         btrfs_clean_old_snapshots(info->tree_root);
6187         btrfs_remove_leaf_refs(info->tree_root, (u64)-1, 1);
6188         mutex_unlock(&root->fs_info->cleaner_mutex);
6189
6190         while (1) {
6191                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6192                 if (ret < 0)
6193                         goto out;
6194 next:
6195                 leaf = path->nodes[0];
6196                 nritems = btrfs_header_nritems(leaf);
6197                 if (path->slots[0] >= nritems) {
6198                         ret = btrfs_next_leaf(root, path);
6199                         if (ret < 0)
6200                                 goto out;
6201                         if (ret == 1) {
6202                                 ret = 0;
6203                                 break;
6204                         }
6205                         leaf = path->nodes[0];
6206                         nritems = btrfs_header_nritems(leaf);
6207                 }
6208
6209                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
6210
6211                 if (key.objectid >= block_group->key.objectid +
6212                     block_group->key.offset)
6213                         break;
6214
6215                 if (progress && need_resched()) {
6216                         btrfs_release_path(root, path);
6217                         cond_resched();
6218                         progress = 0;
6219                         continue;
6220                 }
6221                 progress = 1;
6222
6223                 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY ||
6224                     key.objectid + key.offset <= cur_byte) {
6225                         path->slots[0]++;
6226                         goto next;
6227                 }
6228
6229                 total_found++;
6230                 cur_byte = key.objectid + key.offset;
6231                 btrfs_release_path(root, path);
6232
6233                 __alloc_chunk_for_shrink(root, block_group, 0);
6234                 ret = relocate_one_extent(root, path, &key, block_group,
6235                                           reloc_inode, pass);
6236                 BUG_ON(ret < 0);
6237                 if (ret > 0)
6238                         skipped++;
6239
6240                 key.objectid = cur_byte;
6241                 key.type = 0;
6242                 key.offset = 0;
6243         }
6244
6245         btrfs_release_path(root, path);
6246
6247         if (pass == 0) {
6248                 btrfs_wait_ordered_range(reloc_inode, 0, (u64)-1);
6249                 invalidate_mapping_pages(reloc_inode->i_mapping, 0, -1);
6250         }
6251
6252         if (total_found > 0) {
6253                 printk(KERN_INFO "btrfs found %llu extents in pass %d\n",
6254                        (unsigned long long)total_found, pass);
6255                 pass++;
6256                 if (total_found == skipped && pass > 2) {
6257                         iput(reloc_inode);
6258                         reloc_inode = create_reloc_inode(info, block_group);
6259                         pass = 0;
6260                 }
6261                 goto again;
6262         }
6263
6264         /* delete reloc_inode */
6265         iput(reloc_inode);
6266
6267         /* unpin extents in this range */
6268         trans = btrfs_start_transaction(info->tree_root, 1);
6269         btrfs_commit_transaction(trans, info->tree_root);
6270
6271         spin_lock(&block_group->lock);
6272         WARN_ON(block_group->pinned > 0);
6273         WARN_ON(block_group->reserved > 0);
6274         WARN_ON(btrfs_block_group_used(&block_group->item) > 0);
6275         spin_unlock(&block_group->lock);
6276         put_block_group(block_group);
6277         ret = 0;
6278 out:
6279         btrfs_free_path(path);
6280         return ret;
6281 }
6282
6283 static int find_first_block_group(struct btrfs_root *root,
6284                 struct btrfs_path *path, struct btrfs_key *key)
6285 {
6286         int ret = 0;
6287         struct btrfs_key found_key;
6288         struct extent_buffer *leaf;
6289         int slot;
6290
6291         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
6292         if (ret < 0)
6293                 goto out;
6294
6295         while (1) {
6296                 slot = path->slots[0];
6297                 leaf = path->nodes[0];
6298                 if (slot >= btrfs_header_nritems(leaf)) {
6299                         ret = btrfs_next_leaf(root, path);
6300                         if (ret == 0)
6301                                 continue;
6302                         if (ret < 0)
6303                                 goto out;
6304                         break;
6305                 }
6306                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6307
6308                 if (found_key.objectid >= key->objectid &&
6309                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
6310                         ret = 0;
6311                         goto out;
6312                 }
6313                 path->slots[0]++;
6314         }
6315         ret = -ENOENT;
6316 out:
6317         return ret;
6318 }
6319
6320 int btrfs_free_block_groups(struct btrfs_fs_info *info)
6321 {
6322         struct btrfs_block_group_cache *block_group;
6323         struct rb_node *n;
6324
6325         spin_lock(&info->block_group_cache_lock);
6326         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
6327                 block_group = rb_entry(n, struct btrfs_block_group_cache,
6328                                        cache_node);
6329                 rb_erase(&block_group->cache_node,
6330                          &info->block_group_cache_tree);
6331                 spin_unlock(&info->block_group_cache_lock);
6332
6333                 btrfs_remove_free_space_cache(block_group);
6334                 down_write(&block_group->space_info->groups_sem);
6335                 list_del(&block_group->list);
6336                 up_write(&block_group->space_info->groups_sem);
6337
6338                 WARN_ON(atomic_read(&block_group->count) != 1);
6339                 kfree(block_group);
6340
6341                 spin_lock(&info->block_group_cache_lock);
6342         }
6343         spin_unlock(&info->block_group_cache_lock);
6344         return 0;
6345 }
6346
6347 int btrfs_read_block_groups(struct btrfs_root *root)
6348 {
6349         struct btrfs_path *path;
6350         int ret;
6351         struct btrfs_block_group_cache *cache;
6352         struct btrfs_fs_info *info = root->fs_info;
6353         struct btrfs_space_info *space_info;
6354         struct btrfs_key key;
6355         struct btrfs_key found_key;
6356         struct extent_buffer *leaf;
6357
6358         root = info->extent_root;
6359         key.objectid = 0;
6360         key.offset = 0;
6361         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
6362         path = btrfs_alloc_path();
6363         if (!path)
6364                 return -ENOMEM;
6365
6366         while (1) {
6367                 ret = find_first_block_group(root, path, &key);
6368                 if (ret > 0) {
6369                         ret = 0;
6370                         goto error;
6371                 }
6372                 if (ret != 0)
6373                         goto error;
6374
6375                 leaf = path->nodes[0];
6376                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6377                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
6378                 if (!cache) {
6379                         ret = -ENOMEM;
6380                         break;
6381                 }
6382
6383                 atomic_set(&cache->count, 1);
6384                 spin_lock_init(&cache->lock);
6385                 mutex_init(&cache->alloc_mutex);
6386                 mutex_init(&cache->cache_mutex);
6387                 INIT_LIST_HEAD(&cache->list);
6388                 read_extent_buffer(leaf, &cache->item,
6389                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
6390                                    sizeof(cache->item));
6391                 memcpy(&cache->key, &found_key, sizeof(found_key));
6392
6393                 key.objectid = found_key.objectid + found_key.offset;
6394                 btrfs_release_path(root, path);
6395                 cache->flags = btrfs_block_group_flags(&cache->item);
6396
6397                 ret = update_space_info(info, cache->flags, found_key.offset,
6398                                         btrfs_block_group_used(&cache->item),
6399                                         &space_info);
6400                 BUG_ON(ret);
6401                 cache->space_info = space_info;
6402                 down_write(&space_info->groups_sem);
6403                 list_add_tail(&cache->list, &space_info->block_groups);
6404                 up_write(&space_info->groups_sem);
6405
6406                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
6407                 BUG_ON(ret);
6408
6409                 set_avail_alloc_bits(root->fs_info, cache->flags);
6410                 if (btrfs_chunk_readonly(root, cache->key.objectid))
6411                         set_block_group_readonly(cache);
6412         }
6413         ret = 0;
6414 error:
6415         btrfs_free_path(path);
6416         return ret;
6417 }
6418
6419 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
6420                            struct btrfs_root *root, u64 bytes_used,
6421                            u64 type, u64 chunk_objectid, u64 chunk_offset,
6422                            u64 size)
6423 {
6424         int ret;
6425         struct btrfs_root *extent_root;
6426         struct btrfs_block_group_cache *cache;
6427
6428         extent_root = root->fs_info->extent_root;
6429
6430         root->fs_info->last_trans_new_blockgroup = trans->transid;
6431
6432         cache = kzalloc(sizeof(*cache), GFP_NOFS);
6433         if (!cache)
6434                 return -ENOMEM;
6435
6436         cache->key.objectid = chunk_offset;
6437         cache->key.offset = size;
6438         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
6439         atomic_set(&cache->count, 1);
6440         spin_lock_init(&cache->lock);
6441         mutex_init(&cache->alloc_mutex);
6442         mutex_init(&cache->cache_mutex);
6443         INIT_LIST_HEAD(&cache->list);
6444
6445         btrfs_set_block_group_used(&cache->item, bytes_used);
6446         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
6447         cache->flags = type;
6448         btrfs_set_block_group_flags(&cache->item, type);
6449
6450         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
6451                                 &cache->space_info);
6452         BUG_ON(ret);
6453         down_write(&cache->space_info->groups_sem);
6454         list_add_tail(&cache->list, &cache->space_info->block_groups);
6455         up_write(&cache->space_info->groups_sem);
6456
6457         ret = btrfs_add_block_group_cache(root->fs_info, cache);
6458         BUG_ON(ret);
6459
6460         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
6461                                 sizeof(cache->item));
6462         BUG_ON(ret);
6463
6464         finish_current_insert(trans, extent_root, 0);
6465         ret = del_pending_extents(trans, extent_root, 0);
6466         BUG_ON(ret);
6467         set_avail_alloc_bits(extent_root->fs_info, type);
6468
6469         return 0;
6470 }
6471
6472 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
6473                              struct btrfs_root *root, u64 group_start)
6474 {
6475         struct btrfs_path *path;
6476         struct btrfs_block_group_cache *block_group;
6477         struct btrfs_key key;
6478         int ret;
6479
6480         root = root->fs_info->extent_root;
6481
6482         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
6483         BUG_ON(!block_group);
6484         BUG_ON(!block_group->ro);
6485
6486         memcpy(&key, &block_group->key, sizeof(key));
6487
6488         path = btrfs_alloc_path();
6489         BUG_ON(!path);
6490
6491         spin_lock(&root->fs_info->block_group_cache_lock);
6492         rb_erase(&block_group->cache_node,
6493                  &root->fs_info->block_group_cache_tree);
6494         spin_unlock(&root->fs_info->block_group_cache_lock);
6495         btrfs_remove_free_space_cache(block_group);
6496         down_write(&block_group->space_info->groups_sem);
6497         list_del(&block_group->list);
6498         up_write(&block_group->space_info->groups_sem);
6499
6500         spin_lock(&block_group->space_info->lock);
6501         block_group->space_info->total_bytes -= block_group->key.offset;
6502         block_group->space_info->bytes_readonly -= block_group->key.offset;
6503         spin_unlock(&block_group->space_info->lock);
6504         block_group->space_info->full = 0;
6505
6506         put_block_group(block_group);
6507         put_block_group(block_group);
6508
6509         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
6510         if (ret > 0)
6511                 ret = -EIO;
6512         if (ret < 0)
6513                 goto out;
6514
6515         ret = btrfs_del_item(trans, root, path);
6516 out:
6517         btrfs_free_path(path);
6518         return ret;
6519 }