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