fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/writeback.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/sort.h>
  23 #include "compat.h"
  24 #include "hash.h"
  25 #include "crc32c.h"
  26 #include "ctree.h"
  27 #include "disk-io.h"
  28 #include "print-tree.h"
  29 #include "transaction.h"
  30 #include "volumes.h"
  31 #include "locking.h"
  32 #include "ref-cache.h"
  33
  34 #define PENDING_EXTENT_INSERT 0
  35 #define PENDING_EXTENT_DELETE 1
  36 #define PENDING_BACKREF_UPDATE 2
  37
  38 struct pending_extent_op {
  39         int type;
  40         u64 bytenr;
  41         u64 num_bytes;
  42         u64 parent;
  43         u64 orig_parent;
  44         u64 generation;
  45         u64 orig_generation;
  46         int level;
  47         struct list_head list;
  48         int del;
  49 };
  50
  51 static int finish_current_insert(struct btrfs_trans_handle *trans,
  52                                  struct btrfs_root *extent_root, int all);
  53 static int del_pending_extents(struct btrfs_trans_handle *trans,
  54                                struct btrfs_root *extent_root, int all);
  55 static int pin_down_bytes(struct btrfs_trans_handle *trans,
  56                           struct btrfs_root *root,
  57                           u64 bytenr, u64 num_bytes, int is_data);
  58 static int update_block_group(struct btrfs_trans_handle *trans,
  59                               struct btrfs_root *root,
  60                               u64 bytenr, u64 num_bytes, int alloc,
  61                               int mark_free);
  62
  63 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
  64 {
  65         return (cache->flags & bits) == bits;
  66 }
  67
  68 /*
  69  * this adds the block group to the fs_info rb tree for the block group
  70  * cache
  71  */
  72 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
  73                                 struct btrfs_block_group_cache *block_group)
  74 {
  75         struct rb_node **p;
  76         struct rb_node *parent = NULL;
  77         struct btrfs_block_group_cache *cache;
  78
  79         spin_lock(&info->block_group_cache_lock);
  80         p = &info->block_group_cache_tree.rb_node;
  81
  82         while (*p) {
  83                 parent = *p;
  84                 cache = rb_entry(parent, struct btrfs_block_group_cache,
  85                                  cache_node);
  86                 if (block_group->key.objectid < cache->key.objectid) {
  87                         p = &(*p)->rb_left;
  88                 } else if (block_group->key.objectid > cache->key.objectid) {
  89                         p = &(*p)->rb_right;
  90                 } else {
  91                         spin_unlock(&info->block_group_cache_lock);
  92                         return -EEXIST;
  93                 }
  94         }
  95
  96         rb_link_node(&block_group->cache_node, parent, p);
  97         rb_insert_color(&block_group->cache_node,
  98                         &info->block_group_cache_tree);
  99         spin_unlock(&info->block_group_cache_lock);
 100
 101         return 0;
 102 }
 103
 104 /*
 105  * This will return the block group at or after bytenr if contains is 0, else
 106  * it will return the block group that contains the bytenr
 107  */
 108 static struct btrfs_block_group_cache *
 109 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 110                               int contains)
 111 {
 112         struct btrfs_block_group_cache *cache, *ret = NULL;
 113         struct rb_node *n;
 114         u64 end, start;
 115
 116         spin_lock(&info->block_group_cache_lock);
 117         n = info->block_group_cache_tree.rb_node;
 118
 119         while (n) {
 120                 cache = rb_entry(n, struct btrfs_block_group_cache,
 121                                  cache_node);
 122                 end = cache->key.objectid + cache->key.offset - 1;
 123                 start = cache->key.objectid;
 124
 125                 if (bytenr < start) {
 126                         if (!contains && (!ret || start < ret->key.objectid))
 127                                 ret = cache;
 128                         n = n->rb_left;
 129                 } else if (bytenr > start) {
 130                         if (contains && bytenr <= end) {
 131                                 ret = cache;
 132                                 break;
 133                         }
 134                         n = n->rb_right;
 135                 } else {
 136                         ret = cache;
 137                         break;
 138                 }
 139         }
 140         if (ret)
 141                 atomic_inc(&ret->count);
 142         spin_unlock(&info->block_group_cache_lock);
 143
 144         return ret;
 145 }
 146
 147 /*
 148  * this is only called by cache_block_group, since we could have freed extents
 149  * we need to check the pinned_extents for any extents that can't be used yet
 150  * since their free space will be released as soon as the transaction commits.
 151  */
 152 static int add_new_free_space(struct btrfs_block_group_cache *block_group,
 153                               struct btrfs_fs_info *info, u64 start, u64 end)
 154 {
 155         u64 extent_start, extent_end, size;
 156         int ret;
 157
 158         mutex_lock(&info->pinned_mutex);
 159         while (start < end) {
 160                 ret = find_first_extent_bit(&info->pinned_extents, start,
 161                                             &extent_start, &extent_end,
 162                                             EXTENT_DIRTY);
 163                 if (ret)
 164                         break;
 165
 166                 if (extent_start == start) {
 167                         start = extent_end + 1;
 168                 } else if (extent_start > start && extent_start < end) {
 169                         size = extent_start - start;
 170                         ret = btrfs_add_free_space(block_group, start,
 171                                                    size);
 172                         BUG_ON(ret);
 173                         start = extent_end + 1;
 174                 } else {
 175                         break;
 176                 }
 177         }
 178
 179         if (start < end) {
 180                 size = end - start;
 181                 ret = btrfs_add_free_space(block_group, start, size);
 182                 BUG_ON(ret);
 183         }
 184         mutex_unlock(&info->pinned_mutex);
 185
 186         return 0;
 187 }
 188
 189 static int remove_sb_from_cache(struct btrfs_root *root,
 190                                 struct btrfs_block_group_cache *cache)
 191 {
 192         u64 bytenr;
 193         u64 *logical;
 194         int stripe_len;
 195         int i, nr, ret;
 196
 197         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 198                 bytenr = btrfs_sb_offset(i);
 199                 ret = btrfs_rmap_block(&root->fs_info->mapping_tree,
 200                                        cache->key.objectid, bytenr, 0,
 201                                        &logical, &nr, &stripe_len);
 202                 BUG_ON(ret);
 203                 while (nr--) {
 204                         btrfs_remove_free_space(cache, logical[nr],
 205                                                 stripe_len);
 206                 }
 207                 kfree(logical);
 208         }
 209         return 0;
 210 }
 211
 212 static int cache_block_group(struct btrfs_root *root,
 213                              struct btrfs_block_group_cache *block_group)
 214 {
 215         struct btrfs_path *path;
 216         int ret = 0;
 217         struct btrfs_key key;
 218         struct extent_buffer *leaf;
 219         int slot;
 220         u64 last;
 221
 222         if (!block_group)
 223                 return 0;
 224
 225         root = root->fs_info->extent_root;
 226
 227         if (block_group->cached)
 228                 return 0;
 229
 230         path = btrfs_alloc_path();
 231         if (!path)
 232                 return -ENOMEM;
 233
 234         path->reada = 2;
 235         /*
 236          * we get into deadlocks with paths held by callers of this function.
 237          * since the alloc_mutex is protecting things right now, just
 238          * skip the locking here
 239          */
 240         path->skip_locking = 1;
 241         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 242         key.objectid = last;
 243         key.offset = 0;
 244         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 245         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 246         if (ret < 0)
 247                 goto err;
 248
 249         while (1) {
 250                 leaf = path->nodes[0];
 251                 slot = path->slots[0];
 252                 if (slot >= btrfs_header_nritems(leaf)) {
 253                         ret = btrfs_next_leaf(root, path);
 254                         if (ret < 0)
 255                                 goto err;
 256                         if (ret == 0)
 257                                 continue;
 258                         else
 259                                 break;
 260                 }
 261                 btrfs_item_key_to_cpu(leaf, &key, slot);
 262                 if (key.objectid < block_group->key.objectid)
 263                         goto next;
 264
 265                 if (key.objectid >= block_group->key.objectid +
 266                     block_group->key.offset)
 267                         break;
 268
 269                 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
 270                         add_new_free_space(block_group, root->fs_info, last,
 271                                            key.objectid);
 272
 273                         last = key.objectid + key.offset;
 274                 }
 275 next:
 276                 path->slots[0]++;
 277         }
 278
 279         add_new_free_space(block_group, root->fs_info, last,
 280                            block_group->key.objectid +
 281                            block_group->key.offset);
 282
 283         remove_sb_from_cache(root, block_group);
 284         block_group->cached = 1;
 285         ret = 0;
 286 err:
 287         btrfs_free_path(path);
 288         return ret;
 289 }
 290
 291 /*
 292  * return the block group that starts at or after bytenr
 293  */
 294 static struct btrfs_block_group_cache *
 295 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 296 {
 297         struct btrfs_block_group_cache *cache;
 298
 299         cache = block_group_cache_tree_search(info, bytenr, 0);
 300
 301         return cache;
 302 }
 303
 304 /*
 305  * return the block group that contains teh given bytenr
 306  */
 307 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 308                                                  struct btrfs_fs_info *info,
 309                                                  u64 bytenr)
 310 {
 311         struct btrfs_block_group_cache *cache;
 312
 313         cache = block_group_cache_tree_search(info, bytenr, 1);
 314
 315         return cache;
 316 }
 317
 318 static inline void put_block_group(struct btrfs_block_group_cache *cache)
 319 {
 320         if (atomic_dec_and_test(&cache->count))
 321                 kfree(cache);
 322 }
 323
 324 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 325                                                   u64 flags)
 326 {
 327         struct list_head *head = &info->space_info;
 328         struct btrfs_space_info *found;
 329         list_for_each_entry(found, head, list) {
 330                 if (found->flags == flags)
 331                         return found;
 332         }
 333         return NULL;
 334 }
 335
 336 static u64 div_factor(u64 num, int factor)
 337 {
 338         if (factor == 10)
 339                 return num;
 340         num *= factor;
 341         do_div(num, 10);
 342         return num;
 343 }
 344
 345 u64 btrfs_find_block_group(struct btrfs_root *root,
 346                            u64 search_start, u64 search_hint, int owner)
 347 {
 348         struct btrfs_block_group_cache *cache;
 349         u64 used;
 350         u64 last = max(search_hint, search_start);
 351         u64 group_start = 0;
 352         int full_search = 0;
 353         int factor = 9;
 354         int wrapped = 0;
 355 again:
 356         while (1) {
 357                 cache = btrfs_lookup_first_block_group(root->fs_info, last);
 358                 if (!cache)
 359                         break;
 360
 361                 spin_lock(&cache->lock);
 362                 last = cache->key.objectid + cache->key.offset;
 363                 used = btrfs_block_group_used(&cache->item);
 364
 365                 if ((full_search || !cache->ro) &&
 366                     block_group_bits(cache, BTRFS_BLOCK_GROUP_METADATA)) {
 367                         if (used + cache->pinned + cache->reserved <
 368                             div_factor(cache->key.offset, factor)) {
 369                                 group_start = cache->key.objectid;
 370                                 spin_unlock(&cache->lock);
 371                                 put_block_group(cache);
 372                                 goto found;
 373                         }
 374                 }
 375                 spin_unlock(&cache->lock);
 376                 put_block_group(cache);
 377                 cond_resched();
 378         }
 379         if (!wrapped) {
 380                 last = search_start;
 381                 wrapped = 1;
 382                 goto again;
 383         }
 384         if (!full_search && factor < 10) {
 385                 last = search_start;
 386                 full_search = 1;
 387                 factor = 10;
 388                 goto again;
 389         }
 390 found:
 391         return group_start;
 392 }
 393
 394 /* simple helper to search for an existing extent at a given offset */
 395 int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len)
 396 {
 397         int ret;
 398         struct btrfs_key key;
 399         struct btrfs_path *path;
 400
 401         path = btrfs_alloc_path();
 402         BUG_ON(!path);
 403         key.objectid = start;
 404         key.offset = len;
 405         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
 406         ret = btrfs_search_slot(NULL, root->fs_info->extent_root, &key, path,
 407                                 0, 0);
 408         btrfs_free_path(path);
 409         return ret;
 410 }
 411
 412 /*
 413  * Back reference rules.  Back refs have three main goals:
 414  *
 415  * 1) differentiate between all holders of references to an extent so that
 416  *    when a reference is dropped we can make sure it was a valid reference
 417  *    before freeing the extent.
 418  *
 419  * 2) Provide enough information to quickly find the holders of an extent
 420  *    if we notice a given block is corrupted or bad.
 421  *
 422  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 423  *    maintenance.  This is actually the same as #2, but with a slightly
 424  *    different use case.
 425  *
 426  * File extents can be referenced by:
 427  *
 428  * - multiple snapshots, subvolumes, or different generations in one subvol
 429  * - different files inside a single subvolume
 430  * - different offsets inside a file (bookend extents in file.c)
 431  *
 432  * The extent ref structure has fields for:
 433  *
 434  * - Objectid of the subvolume root
 435  * - Generation number of the tree holding the reference
 436  * - objectid of the file holding the reference
 437  * - number of references holding by parent node (alway 1 for tree blocks)
 438  *
 439  * Btree leaf may hold multiple references to a file extent. In most cases,
 440  * these references are from same file and the corresponding offsets inside
 441  * the file are close together.
 442  *
 443  * When a file extent is allocated the fields are filled in:
 444  *     (root_key.objectid, trans->transid, inode objectid, 1)
 445  *
 446  * When a leaf is cow'd new references are added for every file extent found
 447  * in the leaf.  It looks similar to the create case, but trans->transid will
 448  * be different when the block is cow'd.
 449  *
 450  *     (root_key.objectid, trans->transid, inode objectid,
 451  *      number of references in the leaf)
 452  *
 453  * When a file extent is removed either during snapshot deletion or
 454  * file truncation, we find the corresponding back reference and check
 455  * the following fields:
 456  *
 457  *     (btrfs_header_owner(leaf), btrfs_header_generation(leaf),
 458  *      inode objectid)
 459  *
 460  * Btree extents can be referenced by:
 461  *
 462  * - Different subvolumes
 463  * - Different generations of the same subvolume
 464  *
 465  * When a tree block is created, back references are inserted:
 466  *
 467  * (root->root_key.objectid, trans->transid, level, 1)
 468  *
 469  * When a tree block is cow'd, new back references are added for all the
 470  * blocks it points to. If the tree block isn't in reference counted root,
 471  * the old back references are removed. These new back references are of
 472  * the form (trans->transid will have increased since creation):
 473  *
 474  * (root->root_key.objectid, trans->transid, level, 1)
 475  *
 476  * When a backref is in deleting, the following fields are checked:
 477  *
 478  * if backref was for a tree root:
 479  *     (btrfs_header_owner(itself), btrfs_header_generation(itself), level)
 480  * else
 481  *     (btrfs_header_owner(parent), btrfs_header_generation(parent), level)
 482  *
 483  * Back Reference Key composing:
 484  *
 485  * The key objectid corresponds to the first byte in the extent, the key
 486  * type is set to BTRFS_EXTENT_REF_KEY, and the key offset is the first
 487  * byte of parent extent. If a extent is tree root, the key offset is set
 488  * to the key objectid.
 489  */
 490
 491 static noinline int lookup_extent_backref(struct btrfs_trans_handle *trans,
 492                                           struct btrfs_root *root,
 493                                           struct btrfs_path *path,
 494                                           u64 bytenr, u64 parent,
 495                                           u64 ref_root, u64 ref_generation,
 496                                           u64 owner_objectid, int del)
 497 {
 498         struct btrfs_key key;
 499         struct btrfs_extent_ref *ref;
 500         struct extent_buffer *leaf;
 501         u64 ref_objectid;
 502         int ret;
 503
 504         key.objectid = bytenr;
 505         key.type = BTRFS_EXTENT_REF_KEY;
 506         key.offset = parent;
 507
 508         ret = btrfs_search_slot(trans, root, &key, path, del ? -1 : 0, 1);
 509         if (ret < 0)
 510                 goto out;
 511         if (ret > 0) {
 512                 ret = -ENOENT;
 513                 goto out;
 514         }
 515
 516         leaf = path->nodes[0];
 517         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 518         ref_objectid = btrfs_ref_objectid(leaf, ref);
 519         if (btrfs_ref_root(leaf, ref) != ref_root ||
 520             btrfs_ref_generation(leaf, ref) != ref_generation ||
 521             (ref_objectid != owner_objectid &&
 522              ref_objectid != BTRFS_MULTIPLE_OBJECTIDS)) {
 523                 ret = -EIO;
 524                 WARN_ON(1);
 525                 goto out;
 526         }
 527         ret = 0;
 528 out:
 529         return ret;
 530 }
 531
 532 /*
 533  * updates all the backrefs that are pending on update_list for the
 534  * extent_root
 535  */
 536 static noinline int update_backrefs(struct btrfs_trans_handle *trans,
 537                                     struct btrfs_root *extent_root,
 538                                     struct btrfs_path *path,
 539                                     struct list_head *update_list)
 540 {
 541         struct btrfs_key key;
 542         struct btrfs_extent_ref *ref;
 543         struct btrfs_fs_info *info = extent_root->fs_info;
 544         struct pending_extent_op *op;
 545         struct extent_buffer *leaf;
 546         int ret = 0;
 547         struct list_head *cur = update_list->next;
 548         u64 ref_objectid;
 549         u64 ref_root = extent_root->root_key.objectid;
 550
 551         op = list_entry(cur, struct pending_extent_op, list);
 552
 553 search:
 554         key.objectid = op->bytenr;
 555         key.type = BTRFS_EXTENT_REF_KEY;
 556         key.offset = op->orig_parent;
 557
 558         ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 1);
 559         BUG_ON(ret);
 560
 561         leaf = path->nodes[0];
 562
 563 loop:
 564         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 565
 566         ref_objectid = btrfs_ref_objectid(leaf, ref);
 567
 568         if (btrfs_ref_root(leaf, ref) != ref_root ||
 569             btrfs_ref_generation(leaf, ref) != op->orig_generation ||
 570             (ref_objectid != op->level &&
 571              ref_objectid != BTRFS_MULTIPLE_OBJECTIDS)) {
 572                 printk(KERN_ERR "btrfs couldn't find %llu, parent %llu, "
 573                        "root %llu, owner %u\n",
 574                        (unsigned long long)op->bytenr,
 575                        (unsigned long long)op->orig_parent,
 576                        (unsigned long long)ref_root, op->level);
 577                 btrfs_print_leaf(extent_root, leaf);
 578                 BUG();
 579         }
 580
 581         key.objectid = op->bytenr;
 582         key.offset = op->parent;
 583         key.type = BTRFS_EXTENT_REF_KEY;
 584         ret = btrfs_set_item_key_safe(trans, extent_root, path, &key);
 585         BUG_ON(ret);
 586         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 587         btrfs_set_ref_generation(leaf, ref, op->generation);
 588
 589         cur = cur->next;
 590
 591         list_del_init(&op->list);
 592         unlock_extent(&info->extent_ins, op->bytenr,
 593                       op->bytenr + op->num_bytes - 1, GFP_NOFS);
 594         kfree(op);
 595
 596         if (cur == update_list) {
 597                 btrfs_mark_buffer_dirty(path->nodes[0]);
 598                 btrfs_release_path(extent_root, path);
 599                 goto out;
 600         }
 601
 602         op = list_entry(cur, struct pending_extent_op, list);
 603
 604         path->slots[0]++;
 605         while (path->slots[0] < btrfs_header_nritems(leaf)) {
 606                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 607                 if (key.objectid == op->bytenr &&
 608                     key.type == BTRFS_EXTENT_REF_KEY)
 609                         goto loop;
 610                 path->slots[0]++;
 611         }
 612
 613         btrfs_mark_buffer_dirty(path->nodes[0]);
 614         btrfs_release_path(extent_root, path);
 615         goto search;
 616
 617 out:
 618         return 0;
 619 }
 620
 621 static noinline int insert_extents(struct btrfs_trans_handle *trans,
 622                                    struct btrfs_root *extent_root,
 623                                    struct btrfs_path *path,
 624                                    struct list_head *insert_list, int nr)
 625 {
 626         struct btrfs_key *keys;
 627         u32 *data_size;
 628         struct pending_extent_op *op;
 629         struct extent_buffer *leaf;
 630         struct list_head *cur = insert_list->next;
 631         struct btrfs_fs_info *info = extent_root->fs_info;
 632         u64 ref_root = extent_root->root_key.objectid;
 633         int i = 0, last = 0, ret;
 634         int total = nr * 2;
 635
 636         if (!nr)
 637                 return 0;
 638
 639         keys = kzalloc(total * sizeof(struct btrfs_key), GFP_NOFS);
 640         if (!keys)
 641                 return -ENOMEM;
 642
 643         data_size = kzalloc(total * sizeof(u32), GFP_NOFS);
 644         if (!data_size) {
 645                 kfree(keys);
 646                 return -ENOMEM;
 647         }
 648
 649         list_for_each_entry(op, insert_list, list) {
 650                 keys[i].objectid = op->bytenr;
 651                 keys[i].offset = op->num_bytes;
 652                 keys[i].type = BTRFS_EXTENT_ITEM_KEY;
 653                 data_size[i] = sizeof(struct btrfs_extent_item);
 654                 i++;
 655
 656                 keys[i].objectid = op->bytenr;
 657                 keys[i].offset = op->parent;
 658                 keys[i].type = BTRFS_EXTENT_REF_KEY;
 659                 data_size[i] = sizeof(struct btrfs_extent_ref);
 660                 i++;
 661         }
 662
 663         op = list_entry(cur, struct pending_extent_op, list);
 664         i = 0;
 665         while (i < total) {
 666                 int c;
 667                 ret = btrfs_insert_some_items(trans, extent_root, path,
 668                                               keys+i, data_size+i, total-i);
 669                 BUG_ON(ret < 0);
 670
 671                 if (last && ret > 1)
 672                         BUG();
 673
 674                 leaf = path->nodes[0];
 675                 for (c = 0; c < ret; c++) {
 676                         int ref_first = keys[i].type == BTRFS_EXTENT_REF_KEY;
 677
 678                         /*
 679                          * if the first item we inserted was a backref, then
 680                          * the EXTENT_ITEM will be the odd c's, else it will
 681                          * be the even c's
 682                          */
 683                         if ((ref_first && (c % 2)) ||
 684                             (!ref_first && !(c % 2))) {
 685                                 struct btrfs_extent_item *itm;
 686
 687                                 itm = btrfs_item_ptr(leaf, path->slots[0] + c,
 688                                                      struct btrfs_extent_item);
 689                                 btrfs_set_extent_refs(path->nodes[0], itm, 1);
 690                                 op->del++;
 691                         } else {
 692                                 struct btrfs_extent_ref *ref;
 693
 694                                 ref = btrfs_item_ptr(leaf, path->slots[0] + c,
 695                                                      struct btrfs_extent_ref);
 696                                 btrfs_set_ref_root(leaf, ref, ref_root);
 697                                 btrfs_set_ref_generation(leaf, ref,
 698                                                          op->generation);
 699                                 btrfs_set_ref_objectid(leaf, ref, op->level);
 700                                 btrfs_set_ref_num_refs(leaf, ref, 1);
 701                                 op->del++;
 702                         }
 703
 704                         /*
 705                          * using del to see when its ok to free up the
 706                          * pending_extent_op.  In the case where we insert the
 707                          * last item on the list in order to help do batching
 708                          * we need to not free the extent op until we actually
 709                          * insert the extent_item
 710                          */
 711                         if (op->del == 2) {
 712                                 unlock_extent(&info->extent_ins, op->bytenr,
 713                                               op->bytenr + op->num_bytes - 1,
 714                                               GFP_NOFS);
 715                                 cur = cur->next;
 716                                 list_del_init(&op->list);
 717                                 kfree(op);
 718                                 if (cur != insert_list)
 719                                         op = list_entry(cur,
 720                                                 struct pending_extent_op,
 721                                                 list);
 722                         }
 723                 }
 724                 btrfs_mark_buffer_dirty(leaf);
 725                 btrfs_release_path(extent_root, path);
 726
 727                 /*
 728                  * Ok backref's and items usually go right next to eachother,
 729                  * but if we could only insert 1 item that means that we
 730                  * inserted on the end of a leaf, and we have no idea what may
 731                  * be on the next leaf so we just play it safe.  In order to
 732                  * try and help this case we insert the last thing on our
 733                  * insert list so hopefully it will end up being the last
 734                  * thing on the leaf and everything else will be before it,
 735                  * which will let us insert a whole bunch of items at the same
 736                  * time.
 737                  */
 738                 if (ret == 1 && !last && (i + ret < total)) {
 739                         /*
 740                          * last: where we will pick up the next time around
 741                          * i: our current key to insert, will be total - 1
 742                          * cur: the current op we are screwing with
 743                          * op: duh
 744                          */
 745                         last = i + ret;
 746                         i = total - 1;
 747                         cur = insert_list->prev;
 748                         op = list_entry(cur, struct pending_extent_op, list);
 749                 } else if (last) {
 750                         /*
 751                          * ok we successfully inserted the last item on the
 752                          * list, lets reset everything
 753                          *
 754                          * i: our current key to insert, so where we left off
 755                          *    last time
 756                          * last: done with this
 757                          * cur: the op we are messing with
 758                          * op: duh
 759                          * total: since we inserted the last key, we need to
 760                          *        decrement total so we dont overflow
 761                          */
 762                         i = last;
 763                         last = 0;
 764                         total--;
 765                         if (i < total) {
 766                                 cur = insert_list->next;
 767                                 op = list_entry(cur, struct pending_extent_op,
 768                                                 list);
 769                         }
 770                 } else {
 771                         i += ret;
 772                 }
 773
 774                 cond_resched();
 775         }
 776         ret = 0;
 777         kfree(keys);
 778         kfree(data_size);
 779         return ret;
 780 }
 781
 782 static noinline int insert_extent_backref(struct btrfs_trans_handle *trans,
 783                                           struct btrfs_root *root,
 784                                           struct btrfs_path *path,
 785                                           u64 bytenr, u64 parent,
 786                                           u64 ref_root, u64 ref_generation,
 787                                           u64 owner_objectid)
 788 {
 789         struct btrfs_key key;
 790         struct extent_buffer *leaf;
 791         struct btrfs_extent_ref *ref;
 792         u32 num_refs;
 793         int ret;
 794
 795         key.objectid = bytenr;
 796         key.type = BTRFS_EXTENT_REF_KEY;
 797         key.offset = parent;
 798
 799         ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*ref));
 800         if (ret == 0) {
 801                 leaf = path->nodes[0];
 802                 ref = btrfs_item_ptr(leaf, path->slots[0],
 803                                      struct btrfs_extent_ref);
 804                 btrfs_set_ref_root(leaf, ref, ref_root);
 805                 btrfs_set_ref_generation(leaf, ref, ref_generation);
 806                 btrfs_set_ref_objectid(leaf, ref, owner_objectid);
 807                 btrfs_set_ref_num_refs(leaf, ref, 1);
 808         } else if (ret == -EEXIST) {
 809                 u64 existing_owner;
 810                 BUG_ON(owner_objectid < BTRFS_FIRST_FREE_OBJECTID);
 811                 leaf = path->nodes[0];
 812                 ref = btrfs_item_ptr(leaf, path->slots[0],
 813                                      struct btrfs_extent_ref);
 814                 if (btrfs_ref_root(leaf, ref) != ref_root ||
 815                     btrfs_ref_generation(leaf, ref) != ref_generation) {
 816                         ret = -EIO;
 817                         WARN_ON(1);
 818                         goto out;
 819                 }
 820
 821                 num_refs = btrfs_ref_num_refs(leaf, ref);
 822                 BUG_ON(num_refs == 0);
 823                 btrfs_set_ref_num_refs(leaf, ref, num_refs + 1);
 824
 825                 existing_owner = btrfs_ref_objectid(leaf, ref);
 826                 if (existing_owner != owner_objectid &&
 827                     existing_owner != BTRFS_MULTIPLE_OBJECTIDS) {
 828                         btrfs_set_ref_objectid(leaf, ref,
 829                                         BTRFS_MULTIPLE_OBJECTIDS);
 830                 }
 831                 ret = 0;
 832         } else {
 833                 goto out;
 834         }
 835         btrfs_mark_buffer_dirty(path->nodes[0]);
 836 out:
 837         btrfs_release_path(root, path);
 838         return ret;
 839 }
 840
 841 static noinline int remove_extent_backref(struct btrfs_trans_handle *trans,
 842                                           struct btrfs_root *root,
 843                                           struct btrfs_path *path)
 844 {
 845         struct extent_buffer *leaf;
 846         struct btrfs_extent_ref *ref;
 847         u32 num_refs;
 848         int ret = 0;
 849
 850         leaf = path->nodes[0];
 851         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_ref);
 852         num_refs = btrfs_ref_num_refs(leaf, ref);
 853         BUG_ON(num_refs == 0);
 854         num_refs -= 1;
 855         if (num_refs == 0) {
 856                 ret = btrfs_del_item(trans, root, path);
 857         } else {
 858                 btrfs_set_ref_num_refs(leaf, ref, num_refs);
 859                 btrfs_mark_buffer_dirty(leaf);
 860         }
 861         btrfs_release_path(root, path);
 862         return ret;
 863 }
 864
 865 #ifdef BIO_RW_DISCARD
 866 static void btrfs_issue_discard(struct block_device *bdev,
 867                                 u64 start, u64 len)
 868 {
 869         blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL);
 870 }
 871 #endif
 872
 873 static int btrfs_discard_extent(struct btrfs_root *root, u64 bytenr,
 874                                 u64 num_bytes)
 875 {
 876 #ifdef BIO_RW_DISCARD
 877         int ret;
 878         u64 map_length = num_bytes;
 879         struct btrfs_multi_bio *multi = NULL;
 880
 881         /* Tell the block device(s) that the sectors can be discarded */
 882         ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
 883                               bytenr, &map_length, &multi, 0);
 884         if (!ret) {
 885                 struct btrfs_bio_stripe *stripe = multi->stripes;
 886                 int i;
 887
 888                 if (map_length > num_bytes)
 889                         map_length = num_bytes;
 890
 891                 for (i = 0; i < multi->num_stripes; i++, stripe++) {
 892                         btrfs_issue_discard(stripe->dev->bdev,
 893                                             stripe->physical,
 894                                             map_length);
 895                 }
 896                 kfree(multi);
 897         }
 898
 899         return ret;
 900 #else
 901         return 0;
 902 #endif
 903 }
 904
 905 static noinline int free_extents(struct btrfs_trans_handle *trans,
 906                                  struct btrfs_root *extent_root,
 907                                  struct list_head *del_list)
 908 {
 909         struct btrfs_fs_info *info = extent_root->fs_info;
 910         struct btrfs_path *path;
 911         struct btrfs_key key, found_key;
 912         struct extent_buffer *leaf;
 913         struct list_head *cur;
 914         struct pending_extent_op *op;
 915         struct btrfs_extent_item *ei;
 916         int ret, num_to_del, extent_slot = 0, found_extent = 0;
 917         u32 refs;
 918         u64 bytes_freed = 0;
 919
 920         path = btrfs_alloc_path();
 921         if (!path)
 922                 return -ENOMEM;
 923         path->reada = 1;
 924
 925 search:
 926         /* search for the backref for the current ref we want to delete */
 927         cur = del_list->next;
 928         op = list_entry(cur, struct pending_extent_op, list);
 929         ret = lookup_extent_backref(trans, extent_root, path, op->bytenr,
 930                                     op->orig_parent,
 931                                     extent_root->root_key.objectid,
 932                                     op->orig_generation, op->level, 1);
 933         if (ret) {
 934                 printk(KERN_ERR "btrfs unable to find backref byte nr %llu "
 935                        "root %llu gen %llu owner %u\n",
 936                        (unsigned long long)op->bytenr,
 937                        (unsigned long long)extent_root->root_key.objectid,
 938                        (unsigned long long)op->orig_generation, op->level);
 939                 btrfs_print_leaf(extent_root, path->nodes[0]);
 940                 WARN_ON(1);
 941                 goto out;
 942         }
 943
 944         extent_slot = path->slots[0];
 945         num_to_del = 1;
 946         found_extent = 0;
 947
 948         /*
 949          * if we aren't the first item on the leaf we can move back one and see
 950          * if our ref is right next to our extent item
 951          */
 952         if (likely(extent_slot)) {
 953                 extent_slot--;
 954                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 955                                       extent_slot);
 956                 if (found_key.objectid == op->bytenr &&
 957                     found_key.type == BTRFS_EXTENT_ITEM_KEY &&
 958                     found_key.offset == op->num_bytes) {
 959                         num_to_del++;
 960                         found_extent = 1;
 961                 }
 962         }
 963
 964         /*
 965          * if we didn't find the extent we need to delete the backref and then
 966          * search for the extent item key so we can update its ref count
 967          */
 968         if (!found_extent) {
 969                 key.objectid = op->bytenr;
 970                 key.type = BTRFS_EXTENT_ITEM_KEY;
 971                 key.offset = op->num_bytes;
 972
 973                 ret = remove_extent_backref(trans, extent_root, path);
 974                 BUG_ON(ret);
 975                 btrfs_release_path(extent_root, path);
 976                 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
 977                 BUG_ON(ret);
 978                 extent_slot = path->slots[0];
 979         }
 980
 981         /* this is where we update the ref count for the extent */
 982         leaf = path->nodes[0];
 983         ei = btrfs_item_ptr(leaf, extent_slot, struct btrfs_extent_item);
 984         refs = btrfs_extent_refs(leaf, ei);
 985         BUG_ON(refs == 0);
 986         refs--;
 987         btrfs_set_extent_refs(leaf, ei, refs);
 988
 989         btrfs_mark_buffer_dirty(leaf);
 990
 991         /*
 992          * This extent needs deleting.  The reason cur_slot is extent_slot +
 993          * num_to_del is because extent_slot points to the slot where the extent
 994          * is, and if the backref was not right next to the extent we will be
 995          * deleting at least 1 item, and will want to start searching at the
 996          * slot directly next to extent_slot.  However if we did find the
 997          * backref next to the extent item them we will be deleting at least 2
 998          * items and will want to start searching directly after the ref slot
 999          */
1000         if (!refs) {
1001                 struct list_head *pos, *n, *end;
1002                 int cur_slot = extent_slot+num_to_del;
1003                 u64 super_used;
1004                 u64 root_used;
1005
1006                 path->slots[0] = extent_slot;
1007                 bytes_freed = op->num_bytes;
1008
1009                 mutex_lock(&info->pinned_mutex);
1010                 ret = pin_down_bytes(trans, extent_root, op->bytenr,
1011                                      op->num_bytes, op->level >=
1012                                      BTRFS_FIRST_FREE_OBJECTID);
1013                 mutex_unlock(&info->pinned_mutex);
1014                 BUG_ON(ret < 0);
1015                 op->del = ret;
1016
1017                 /*
1018                  * we need to see if we can delete multiple things at once, so
1019                  * start looping through the list of extents we are wanting to
1020                  * delete and see if their extent/backref's are right next to
1021                  * eachother and the extents only have 1 ref
1022                  */
1023                 for (pos = cur->next; pos != del_list; pos = pos->next) {
1024                         struct pending_extent_op *tmp;
1025
1026                         tmp = list_entry(pos, struct pending_extent_op, list);
1027
1028                         /* we only want to delete extent+ref at this stage */
1029                         if (cur_slot >= btrfs_header_nritems(leaf) - 1)
1030                                 break;
1031
1032                         btrfs_item_key_to_cpu(leaf, &found_key, cur_slot);
1033                         if (found_key.objectid != tmp->bytenr ||
1034                             found_key.type != BTRFS_EXTENT_ITEM_KEY ||
1035                             found_key.offset != tmp->num_bytes)
1036                                 break;
1037
1038                         /* check to make sure this extent only has one ref */
1039                         ei = btrfs_item_ptr(leaf, cur_slot,
1040                                             struct btrfs_extent_item);
1041                         if (btrfs_extent_refs(leaf, ei) != 1)
1042                                 break;
1043
1044                         btrfs_item_key_to_cpu(leaf, &found_key, cur_slot+1);
1045                         if (found_key.objectid != tmp->bytenr ||
1046                             found_key.type != BTRFS_EXTENT_REF_KEY ||
1047                             found_key.offset != tmp->orig_parent)
1048                                 break;
1049
1050                         /*
1051                          * the ref is right next to the extent, we can set the
1052                          * ref count to 0 since we will delete them both now
1053                          */
1054                         btrfs_set_extent_refs(leaf, ei, 0);
1055
1056                         /* pin down the bytes for this extent */
1057                         mutex_lock(&info->pinned_mutex);
1058                         ret = pin_down_bytes(trans, extent_root, tmp->bytenr,
1059                                              tmp->num_bytes, tmp->level >=
1060                                              BTRFS_FIRST_FREE_OBJECTID);
1061                         mutex_unlock(&info->pinned_mutex);
1062                         BUG_ON(ret < 0);
1063
1064                         /*
1065                          * use the del field to tell if we need to go ahead and
1066                          * free up the extent when we delete the item or not.
1067                          */
1068                         tmp->del = ret;
1069                         bytes_freed += tmp->num_bytes;
1070
1071                         num_to_del += 2;
1072                         cur_slot += 2;
1073                 }
1074                 end = pos;
1075
1076                 /* update the free space counters */
1077                 spin_lock(&info->delalloc_lock);
1078                 super_used = btrfs_super_bytes_used(&info->super_copy);
1079                 btrfs_set_super_bytes_used(&info->super_copy,
1080                                            super_used - bytes_freed);
1081
1082                 root_used = btrfs_root_used(&extent_root->root_item);
1083                 btrfs_set_root_used(&extent_root->root_item,
1084                                     root_used - bytes_freed);
1085                 spin_unlock(&info->delalloc_lock);
1086
1087                 /* delete the items */
1088                 ret = btrfs_del_items(trans, extent_root, path,
1089                                       path->slots[0], num_to_del);
1090                 BUG_ON(ret);
1091
1092                 /*
1093                  * loop through the extents we deleted and do the cleanup work
1094                  * on them
1095                  */
1096                 for (pos = cur, n = pos->next; pos != end;
1097                      pos = n, n = pos->next) {
1098                         struct pending_extent_op *tmp;
1099                         tmp = list_entry(pos, struct pending_extent_op, list);
1100
1101                         /*
1102                          * remember tmp->del tells us wether or not we pinned
1103                          * down the extent
1104                          */
1105                         ret = update_block_group(trans, extent_root,
1106                                                  tmp->bytenr, tmp->num_bytes, 0,
1107                                                  tmp->del);
1108                         BUG_ON(ret);
1109
1110                         list_del_init(&tmp->list);
1111                         unlock_extent(&info->extent_ins, tmp->bytenr,
1112                                       tmp->bytenr + tmp->num_bytes - 1,
1113                                       GFP_NOFS);
1114                         kfree(tmp);
1115                 }
1116         } else if (refs && found_extent) {
1117                 /*
1118                  * the ref and extent were right next to eachother, but the
1119                  * extent still has a ref, so just free the backref and keep
1120                  * going
1121                  */
1122                 ret = remove_extent_backref(trans, extent_root, path);
1123                 BUG_ON(ret);
1124
1125                 list_del_init(&op->list);
1126                 unlock_extent(&info->extent_ins, op->bytenr,
1127                               op->bytenr + op->num_bytes - 1, GFP_NOFS);
1128                 kfree(op);
1129         } else {
1130                 /*
1131                  * the extent has multiple refs and the backref we were looking
1132                  * for was not right next to it, so just unlock and go next,
1133                  * we're good to go
1134                  */
1135                 list_del_init(&op->list);
1136                 unlock_extent(&info->extent_ins, op->bytenr,
1137                               op->bytenr + op->num_bytes - 1, GFP_NOFS);
1138                 kfree(op);
1139         }
1140
1141         btrfs_release_path(extent_root, path);
1142         if (!list_empty(del_list))
1143                 goto search;
1144
1145 out:
1146         btrfs_free_path(path);
1147         return ret;
1148 }
1149
1150 static int __btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
1151                                      struct btrfs_root *root, u64 bytenr,
1152                                      u64 orig_parent, u64 parent,
1153                                      u64 orig_root, u64 ref_root,
1154                                      u64 orig_generation, u64 ref_generation,
1155                                      u64 owner_objectid)
1156 {
1157         int ret;
1158         struct btrfs_root *extent_root = root->fs_info->extent_root;
1159         struct btrfs_path *path;
1160
1161         if (root == root->fs_info->extent_root) {
1162                 struct pending_extent_op *extent_op;
1163                 u64 num_bytes;
1164
1165                 BUG_ON(owner_objectid >= BTRFS_MAX_LEVEL);
1166                 num_bytes = btrfs_level_size(root, (int)owner_objectid);
1167                 mutex_lock(&root->fs_info->extent_ins_mutex);
1168                 if (test_range_bit(&root->fs_info->extent_ins, bytenr,
1169                                 bytenr + num_bytes - 1, EXTENT_WRITEBACK, 0)) {
1170                         u64 priv;
1171                         ret = get_state_private(&root->fs_info->extent_ins,
1172                                                 bytenr, &priv);
1173                         BUG_ON(ret);
1174                         extent_op = (struct pending_extent_op *)
1175                                                         (unsigned long)priv;
1176                         BUG_ON(extent_op->parent != orig_parent);
1177                         BUG_ON(extent_op->generation != orig_generation);
1178
1179                         extent_op->parent = parent;
1180                         extent_op->generation = ref_generation;
1181                 } else {
1182                         extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
1183                         BUG_ON(!extent_op);
1184
1185                         extent_op->type = PENDING_BACKREF_UPDATE;
1186                         extent_op->bytenr = bytenr;
1187                         extent_op->num_bytes = num_bytes;
1188                         extent_op->parent = parent;
1189                         extent_op->orig_parent = orig_parent;
1190                         extent_op->generation = ref_generation;
1191                         extent_op->orig_generation = orig_generation;
1192                         extent_op->level = (int)owner_objectid;
1193                         INIT_LIST_HEAD(&extent_op->list);
1194                         extent_op->del = 0;
1195
1196                         set_extent_bits(&root->fs_info->extent_ins,
1197                                         bytenr, bytenr + num_bytes - 1,
1198                                         EXTENT_WRITEBACK, GFP_NOFS);
1199                         set_state_private(&root->fs_info->extent_ins,
1200                                           bytenr, (unsigned long)extent_op);
1201                 }
1202                 mutex_unlock(&root->fs_info->extent_ins_mutex);
1203                 return 0;
1204         }
1205
1206         path = btrfs_alloc_path();
1207         if (!path)
1208                 return -ENOMEM;
1209         ret = lookup_extent_backref(trans, extent_root, path,
1210                                     bytenr, orig_parent, orig_root,
1211                                     orig_generation, owner_objectid, 1);
1212         if (ret)
1213                 goto out;
1214         ret = remove_extent_backref(trans, extent_root, path);
1215         if (ret)
1216                 goto out;
1217         ret = insert_extent_backref(trans, extent_root, path, bytenr,
1218                                     parent, ref_root, ref_generation,
1219                                     owner_objectid);
1220         BUG_ON(ret);
1221         finish_current_insert(trans, extent_root, 0);
1222         del_pending_extents(trans, extent_root, 0);
1223 out:
1224         btrfs_free_path(path);
1225         return ret;
1226 }
1227
1228 int btrfs_update_extent_ref(struct btrfs_trans_handle *trans,
1229                             struct btrfs_root *root, u64 bytenr,
1230                             u64 orig_parent, u64 parent,
1231                             u64 ref_root, u64 ref_generation,
1232                             u64 owner_objectid)
1233 {
1234         int ret;
1235         if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
1236             owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
1237                 return 0;
1238         ret = __btrfs_update_extent_ref(trans, root, bytenr, orig_parent,
1239                                         parent, ref_root, ref_root,
1240                                         ref_generation, ref_generation,
1241                                         owner_objectid);
1242         return ret;
1243 }
1244
1245 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1246                                   struct btrfs_root *root, u64 bytenr,
1247                                   u64 orig_parent, u64 parent,
1248                                   u64 orig_root, u64 ref_root,
1249                                   u64 orig_generation, u64 ref_generation,
1250                                   u64 owner_objectid)
1251 {
1252         struct btrfs_path *path;
1253         int ret;
1254         struct btrfs_key key;
1255         struct extent_buffer *l;
1256         struct btrfs_extent_item *item;
1257         u32 refs;
1258
1259         path = btrfs_alloc_path();
1260         if (!path)
1261                 return -ENOMEM;
1262
1263         path->reada = 1;
1264         key.objectid = bytenr;
1265         key.type = BTRFS_EXTENT_ITEM_KEY;
1266         key.offset = (u64)-1;
1267
1268         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
1269                                 0, 1);
1270         if (ret < 0)
1271                 return ret;
1272         BUG_ON(ret == 0 || path->slots[0] == 0);
1273
1274         path->slots[0]--;
1275         l = path->nodes[0];
1276
1277         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1278         if (key.objectid != bytenr) {
1279                 btrfs_print_leaf(root->fs_info->extent_root, path->nodes[0]);
1280                 printk(KERN_ERR "btrfs wanted %llu found %llu\n",
1281                        (unsigned long long)bytenr,
1282                        (unsigned long long)key.objectid);
1283                 BUG();
1284         }
1285         BUG_ON(key.type != BTRFS_EXTENT_ITEM_KEY);
1286
1287         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
1288         refs = btrfs_extent_refs(l, item);
1289         btrfs_set_extent_refs(l, item, refs + 1);
1290         btrfs_mark_buffer_dirty(path->nodes[0]);
1291
1292         btrfs_release_path(root->fs_info->extent_root, path);
1293
1294         path->reada = 1;
1295         ret = insert_extent_backref(trans, root->fs_info->extent_root,
1296                                     path, bytenr, parent,
1297                                     ref_root, ref_generation,
1298                                     owner_objectid);
1299         BUG_ON(ret);
1300         finish_current_insert(trans, root->fs_info->extent_root, 0);
1301         del_pending_extents(trans, root->fs_info->extent_root, 0);
1302
1303         btrfs_free_path(path);
1304         return 0;
1305 }
1306
1307 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1308                          struct btrfs_root *root,
1309                          u64 bytenr, u64 num_bytes, u64 parent,
1310                          u64 ref_root, u64 ref_generation,
1311                          u64 owner_objectid)
1312 {
1313         int ret;
1314         if (ref_root == BTRFS_TREE_LOG_OBJECTID &&
1315             owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
1316                 return 0;
1317         ret = __btrfs_inc_extent_ref(trans, root, bytenr, 0, parent,
1318                                      0, ref_root, 0, ref_generation,
1319                                      owner_objectid);
1320         return ret;
1321 }
1322
1323 int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
1324                          struct btrfs_root *root)
1325 {
1326         u64 start;
1327         u64 end;
1328         int ret;
1329
1330         while(1) {
1331                 finish_current_insert(trans, root->fs_info->extent_root, 1);
1332                 del_pending_extents(trans, root->fs_info->extent_root, 1);
1333
1334                 /* is there more work to do? */
1335                 ret = find_first_extent_bit(&root->fs_info->pending_del,
1336                                             0, &start, &end, EXTENT_WRITEBACK);
1337                 if (!ret)
1338                         continue;
1339                 ret = find_first_extent_bit(&root->fs_info->extent_ins,
1340                                             0, &start, &end, EXTENT_WRITEBACK);
1341                 if (!ret)
1342                         continue;
1343                 break;
1344         }
1345         return 0;
1346 }
1347
1348 int btrfs_lookup_extent_ref(struct btrfs_trans_handle *trans,
1349                             struct btrfs_root *root, u64 bytenr,
1350                             u64 num_bytes, u32 *refs)
1351 {
1352         struct btrfs_path *path;
1353         int ret;
1354         struct btrfs_key key;
1355         struct extent_buffer *l;
1356         struct btrfs_extent_item *item;
1357
1358         WARN_ON(num_bytes < root->sectorsize);
1359         path = btrfs_alloc_path();
1360         path->reada = 1;
1361         key.objectid = bytenr;
1362         key.offset = num_bytes;
1363         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
1364         ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
1365                                 0, 0);
1366         if (ret < 0)
1367                 goto out;
1368         if (ret != 0) {
1369                 btrfs_print_leaf(root, path->nodes[0]);
1370                 printk(KERN_INFO "btrfs failed to find block number %llu\n",
1371                        (unsigned long long)bytenr);
1372                 BUG();
1373         }
1374         l = path->nodes[0];
1375         item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
1376         *refs = btrfs_extent_refs(l, item);
1377 out:
1378         btrfs_free_path(path);
1379         return 0;
1380 }
1381
1382 int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
1383                           struct btrfs_root *root, u64 objectid, u64 bytenr)
1384 {
1385         struct btrfs_root *extent_root = root->fs_info->extent_root;
1386         struct btrfs_path *path;
1387         struct extent_buffer *leaf;
1388         struct btrfs_extent_ref *ref_item;
1389         struct btrfs_key key;
1390         struct btrfs_key found_key;
1391         u64 ref_root;
1392         u64 last_snapshot;
1393         u32 nritems;
1394         int ret;
1395
1396         key.objectid = bytenr;
1397         key.offset = (u64)-1;
1398         key.type = BTRFS_EXTENT_ITEM_KEY;
1399
1400         path = btrfs_alloc_path();
1401         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
1402         if (ret < 0)
1403                 goto out;
1404         BUG_ON(ret == 0);
1405
1406         ret = -ENOENT;
1407         if (path->slots[0] == 0)
1408                 goto out;
1409
1410         path->slots[0]--;
1411         leaf = path->nodes[0];
1412         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1413
1414         if (found_key.objectid != bytenr ||
1415             found_key.type != BTRFS_EXTENT_ITEM_KEY)
1416                 goto out;
1417
1418         last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1419         while (1) {
1420                 leaf = path->nodes[0];
1421                 nritems = btrfs_header_nritems(leaf);
1422                 if (path->slots[0] >= nritems) {
1423                         ret = btrfs_next_leaf(extent_root, path);
1424                         if (ret < 0)
1425                                 goto out;
1426                         if (ret == 0)
1427                                 continue;
1428                         break;
1429                 }
1430                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1431                 if (found_key.objectid != bytenr)
1432                         break;
1433
1434                 if (found_key.type != BTRFS_EXTENT_REF_KEY) {
1435                         path->slots[0]++;
1436                         continue;
1437                 }
1438
1439                 ref_item = btrfs_item_ptr(leaf, path->slots[0],
1440                                           struct btrfs_extent_ref);
1441                 ref_root = btrfs_ref_root(leaf, ref_item);
1442                 if ((ref_root != root->root_key.objectid &&
1443                      ref_root != BTRFS_TREE_LOG_OBJECTID) ||
1444                      objectid != btrfs_ref_objectid(leaf, ref_item)) {
1445                         ret = 1;
1446                         goto out;
1447                 }
1448                 if (btrfs_ref_generation(leaf, ref_item) <= last_snapshot) {
1449                         ret = 1;
1450                         goto out;
1451                 }
1452
1453                 path->slots[0]++;
1454         }
1455         ret = 0;
1456 out:
1457         btrfs_free_path(path);
1458         return ret;
1459 }
1460
1461 int btrfs_cache_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1462                     struct extent_buffer *buf, u32 nr_extents)
1463 {
1464         struct btrfs_key key;
1465         struct btrfs_file_extent_item *fi;
1466         u64 root_gen;
1467         u32 nritems;
1468         int i;
1469         int level;
1470         int ret = 0;
1471         int shared = 0;
1472
1473         if (!root->ref_cows)
1474                 return 0;
1475
1476         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1477                 shared = 0;
1478                 root_gen = root->root_key.offset;
1479         } else {
1480                 shared = 1;
1481                 root_gen = trans->transid - 1;
1482         }
1483
1484         level = btrfs_header_level(buf);
1485         nritems = btrfs_header_nritems(buf);
1486
1487         if (level == 0) {
1488                 struct btrfs_leaf_ref *ref;
1489                 struct btrfs_extent_info *info;
1490
1491                 ref = btrfs_alloc_leaf_ref(root, nr_extents);
1492                 if (!ref) {
1493                         ret = -ENOMEM;
1494                         goto out;
1495                 }
1496
1497                 ref->root_gen = root_gen;
1498                 ref->bytenr = buf->start;
1499                 ref->owner = btrfs_header_owner(buf);
1500                 ref->generation = btrfs_header_generation(buf);
1501                 ref->nritems = nr_extents;
1502                 info = ref->extents;
1503
1504                 for (i = 0; nr_extents > 0 && i < nritems; i++) {
1505                         u64 disk_bytenr;
1506                         btrfs_item_key_to_cpu(buf, &key, i);
1507                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1508                                 continue;
1509                         fi = btrfs_item_ptr(buf, i,
1510                                             struct btrfs_file_extent_item);
1511                         if (btrfs_file_extent_type(buf, fi) ==
1512                             BTRFS_FILE_EXTENT_INLINE)
1513                                 continue;
1514                         disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1515                         if (disk_bytenr == 0)
1516                                 continue;
1517
1518                         info->bytenr = disk_bytenr;
1519                         info->num_bytes =
1520                                 btrfs_file_extent_disk_num_bytes(buf, fi);
1521                         info->objectid = key.objectid;
1522                         info->offset = key.offset;
1523                         info++;
1524                 }
1525
1526                 ret = btrfs_add_leaf_ref(root, ref, shared);
1527                 if (ret == -EEXIST && shared) {
1528                         struct btrfs_leaf_ref *old;
1529                         old = btrfs_lookup_leaf_ref(root, ref->bytenr);
1530                         BUG_ON(!old);
1531                         btrfs_remove_leaf_ref(root, old);
1532                         btrfs_free_leaf_ref(root, old);
1533                         ret = btrfs_add_leaf_ref(root, ref, shared);
1534                 }
1535                 WARN_ON(ret);
1536                 btrfs_free_leaf_ref(root, ref);
1537         }
1538 out:
1539         return ret;
1540 }
1541
1542 /* when a block goes through cow, we update the reference counts of
1543  * everything that block points to.  The internal pointers of the block
1544  * can be in just about any order, and it is likely to have clusters of
1545  * things that are close together and clusters of things that are not.
1546  *
1547  * To help reduce the seeks that come with updating all of these reference
1548  * counts, sort them by byte number before actual updates are done.
1549  *
1550  * struct refsort is used to match byte number to slot in the btree block.
1551  * we sort based on the byte number and then use the slot to actually
1552  * find the item.
1553  *
1554  * struct refsort is smaller than strcut btrfs_item and smaller than
1555  * struct btrfs_key_ptr.  Since we're currently limited to the page size
1556  * for a btree block, there's no way for a kmalloc of refsorts for a
1557  * single node to be bigger than a page.
1558  */
1559 struct refsort {
1560         u64 bytenr;
1561         u32 slot;
1562 };
1563
1564 /*
1565  * for passing into sort()
1566  */
1567 static int refsort_cmp(const void *a_void, const void *b_void)
1568 {
1569         const struct refsort *a = a_void;
1570         const struct refsort *b = b_void;
1571
1572         if (a->bytenr < b->bytenr)
1573                 return -1;
1574         if (a->bytenr > b->bytenr)
1575                 return 1;
1576         return 0;
1577 }
1578
1579
1580 noinline int btrfs_inc_ref(struct btrfs_trans_handle *trans,
1581                            struct btrfs_root *root,
1582                            struct extent_buffer *orig_buf,
1583                            struct extent_buffer *buf, u32 *nr_extents)
1584 {
1585         u64 bytenr;
1586         u64 ref_root;
1587         u64 orig_root;
1588         u64 ref_generation;
1589         u64 orig_generation;
1590         struct refsort *sorted;
1591         u32 nritems;
1592         u32 nr_file_extents = 0;
1593         struct btrfs_key key;
1594         struct btrfs_file_extent_item *fi;
1595         int i;
1596         int level;
1597         int ret = 0;
1598         int faili = 0;
1599         int refi = 0;
1600         int slot;
1601         int (*process_func)(struct btrfs_trans_handle *, struct btrfs_root *,
1602                             u64, u64, u64, u64, u64, u64, u64, u64);
1603
1604         ref_root = btrfs_header_owner(buf);
1605         ref_generation = btrfs_header_generation(buf);
1606         orig_root = btrfs_header_owner(orig_buf);
1607         orig_generation = btrfs_header_generation(orig_buf);
1608
1609         nritems = btrfs_header_nritems(buf);
1610         level = btrfs_header_level(buf);
1611
1612         sorted = kmalloc(sizeof(struct refsort) * nritems, GFP_NOFS);
1613         BUG_ON(!sorted);
1614
1615         if (root->ref_cows) {
1616                 process_func = __btrfs_inc_extent_ref;
1617         } else {
1618                 if (level == 0 &&
1619                     root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
1620                         goto out;
1621                 if (level != 0 &&
1622                     root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID)
1623                         goto out;
1624                 process_func = __btrfs_update_extent_ref;
1625         }
1626
1627         /*
1628          * we make two passes through the items.  In the first pass we
1629          * only record the byte number and slot.  Then we sort based on
1630          * byte number and do the actual work based on the sorted results
1631          */
1632         for (i = 0; i < nritems; i++) {
1633                 cond_resched();
1634                 if (level == 0) {
1635                         btrfs_item_key_to_cpu(buf, &key, i);
1636                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1637                                 continue;
1638                         fi = btrfs_item_ptr(buf, i,
1639                                             struct btrfs_file_extent_item);
1640                         if (btrfs_file_extent_type(buf, fi) ==
1641                             BTRFS_FILE_EXTENT_INLINE)
1642                                 continue;
1643                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1644                         if (bytenr == 0)
1645                                 continue;
1646
1647                         nr_file_extents++;
1648                         sorted[refi].bytenr = bytenr;
1649                         sorted[refi].slot = i;
1650                         refi++;
1651                 } else {
1652                         bytenr = btrfs_node_blockptr(buf, i);
1653                         sorted[refi].bytenr = bytenr;
1654                         sorted[refi].slot = i;
1655                         refi++;
1656                 }
1657         }
1658         /*
1659          * if refi == 0, we didn't actually put anything into the sorted
1660          * array and we're done
1661          */
1662         if (refi == 0)
1663                 goto out;
1664
1665         sort(sorted, refi, sizeof(struct refsort), refsort_cmp, NULL);
1666
1667         for (i = 0; i < refi; i++) {
1668                 cond_resched();
1669                 slot = sorted[i].slot;
1670                 bytenr = sorted[i].bytenr;
1671
1672                 if (level == 0) {
1673                         btrfs_item_key_to_cpu(buf, &key, slot);
1674
1675                         ret = process_func(trans, root, bytenr,
1676                                            orig_buf->start, buf->start,
1677                                            orig_root, ref_root,
1678                                            orig_generation, ref_generation,
1679                                            key.objectid);
1680
1681                         if (ret) {
1682                                 faili = slot;
1683                                 WARN_ON(1);
1684                                 goto fail;
1685                         }
1686                 } else {
1687                         ret = process_func(trans, root, bytenr,
1688                                            orig_buf->start, buf->start,
1689                                            orig_root, ref_root,
1690                                            orig_generation, ref_generation,
1691                                            level - 1);
1692                         if (ret) {
1693                                 faili = slot;
1694                                 WARN_ON(1);
1695                                 goto fail;
1696                         }
1697                 }
1698         }
1699 out:
1700         kfree(sorted);
1701         if (nr_extents) {
1702                 if (level == 0)
1703                         *nr_extents = nr_file_extents;
1704                 else
1705                         *nr_extents = nritems;
1706         }
1707         return 0;
1708 fail:
1709         kfree(sorted);
1710         WARN_ON(1);
1711         return ret;
1712 }
1713
1714 int btrfs_update_ref(struct btrfs_trans_handle *trans,
1715                      struct btrfs_root *root, struct extent_buffer *orig_buf,
1716                      struct extent_buffer *buf, int start_slot, int nr)
1717
1718 {
1719         u64 bytenr;
1720         u64 ref_root;
1721         u64 orig_root;
1722         u64 ref_generation;
1723         u64 orig_generation;
1724         struct btrfs_key key;
1725         struct btrfs_file_extent_item *fi;
1726         int i;
1727         int ret;
1728         int slot;
1729         int level;
1730
1731         BUG_ON(start_slot < 0);
1732         BUG_ON(start_slot + nr > btrfs_header_nritems(buf));
1733
1734         ref_root = btrfs_header_owner(buf);
1735         ref_generation = btrfs_header_generation(buf);
1736         orig_root = btrfs_header_owner(orig_buf);
1737         orig_generation = btrfs_header_generation(orig_buf);
1738         level = btrfs_header_level(buf);
1739
1740         if (!root->ref_cows) {
1741                 if (level == 0 &&
1742                     root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID)
1743                         return 0;
1744                 if (level != 0 &&
1745                     root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID)
1746                         return 0;
1747         }
1748
1749         for (i = 0, slot = start_slot; i < nr; i++, slot++) {
1750                 cond_resched();
1751                 if (level == 0) {
1752                         btrfs_item_key_to_cpu(buf, &key, slot);
1753                         if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1754                                 continue;
1755                         fi = btrfs_item_ptr(buf, slot,
1756                                             struct btrfs_file_extent_item);
1757                         if (btrfs_file_extent_type(buf, fi) ==
1758                             BTRFS_FILE_EXTENT_INLINE)
1759                                 continue;
1760                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
1761                         if (bytenr == 0)
1762                                 continue;
1763                         ret = __btrfs_update_extent_ref(trans, root, bytenr,
1764                                             orig_buf->start, buf->start,
1765                                             orig_root, ref_root,
1766                                             orig_generation, ref_generation,
1767                                             key.objectid);
1768                         if (ret)
1769                                 goto fail;
1770                 } else {
1771                         bytenr = btrfs_node_blockptr(buf, slot);
1772                         ret = __btrfs_update_extent_ref(trans, root, bytenr,
1773                                             orig_buf->start, buf->start,
1774                                             orig_root, ref_root,
1775                                             orig_generation, ref_generation,
1776                                             level - 1);
1777                         if (ret)
1778                                 goto fail;
1779                 }
1780         }
1781         return 0;
1782 fail:
1783         WARN_ON(1);
1784         return -1;
1785 }
1786
1787 static int write_one_cache_group(struct btrfs_trans_handle *trans,
1788                                  struct btrfs_root *root,
1789                                  struct btrfs_path *path,
1790                                  struct btrfs_block_group_cache *cache)
1791 {
1792         int ret;
1793         int pending_ret;
1794         struct btrfs_root *extent_root = root->fs_info->extent_root;
1795         unsigned long bi;
1796         struct extent_buffer *leaf;
1797
1798         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
1799         if (ret < 0)
1800                 goto fail;
1801         BUG_ON(ret);
1802
1803         leaf = path->nodes[0];
1804         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
1805         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
1806         btrfs_mark_buffer_dirty(leaf);
1807         btrfs_release_path(extent_root, path);
1808 fail:
1809         finish_current_insert(trans, extent_root, 0);
1810         pending_ret = del_pending_extents(trans, extent_root, 0);
1811         if (ret)
1812                 return ret;
1813         if (pending_ret)
1814                 return pending_ret;
1815         return 0;
1816
1817 }
1818
1819 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
1820                                    struct btrfs_root *root)
1821 {
1822         struct btrfs_block_group_cache *cache, *entry;
1823         struct rb_node *n;
1824         int err = 0;
1825         int werr = 0;
1826         struct btrfs_path *path;
1827         u64 last = 0;
1828
1829         path = btrfs_alloc_path();
1830         if (!path)
1831                 return -ENOMEM;
1832
1833         while (1) {
1834                 cache = NULL;
1835                 spin_lock(&root->fs_info->block_group_cache_lock);
1836                 for (n = rb_first(&root->fs_info->block_group_cache_tree);
1837                      n; n = rb_next(n)) {
1838                         entry = rb_entry(n, struct btrfs_block_group_cache,
1839                                          cache_node);
1840                         if (entry->dirty) {
1841                                 cache = entry;
1842                                 break;
1843                         }
1844                 }
1845                 spin_unlock(&root->fs_info->block_group_cache_lock);
1846
1847                 if (!cache)
1848                         break;
1849
1850                 cache->dirty = 0;
1851                 last += cache->key.offset;
1852
1853                 err = write_one_cache_group(trans, root,
1854                                             path, cache);
1855                 /*
1856                  * if we fail to write the cache group, we want
1857                  * to keep it marked dirty in hopes that a later
1858                  * write will work
1859                  */
1860                 if (err) {
1861                         werr = err;
1862                         continue;
1863                 }
1864         }
1865         btrfs_free_path(path);
1866         return werr;
1867 }
1868
1869 int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr)
1870 {
1871         struct btrfs_block_group_cache *block_group;
1872         int readonly = 0;
1873
1874         block_group = btrfs_lookup_block_group(root->fs_info, bytenr);
1875         if (!block_group || block_group->ro)
1876                 readonly = 1;
1877         if (block_group)
1878                 put_block_group(block_group);
1879         return readonly;
1880 }
1881
1882 static int update_space_info(struct btrfs_fs_info *info, u64 flags,
1883                              u64 total_bytes, u64 bytes_used,
1884                              struct btrfs_space_info **space_info)
1885 {
1886         struct btrfs_space_info *found;
1887
1888         found = __find_space_info(info, flags);
1889         if (found) {
1890                 spin_lock(&found->lock);
1891                 found->total_bytes += total_bytes;
1892                 found->bytes_used += bytes_used;
1893                 found->full = 0;
1894                 spin_unlock(&found->lock);
1895                 *space_info = found;
1896                 return 0;
1897         }
1898         found = kzalloc(sizeof(*found), GFP_NOFS);
1899         if (!found)
1900                 return -ENOMEM;
1901
1902         list_add(&found->list, &info->space_info);
1903         INIT_LIST_HEAD(&found->block_groups);
1904         init_rwsem(&found->groups_sem);
1905         spin_lock_init(&found->lock);
1906         found->flags = flags;
1907         found->total_bytes = total_bytes;
1908         found->bytes_used = bytes_used;
1909         found->bytes_pinned = 0;
1910         found->bytes_reserved = 0;
1911         found->bytes_readonly = 0;
1912         found->full = 0;
1913         found->force_alloc = 0;
1914         *space_info = found;
1915         return 0;
1916 }
1917
1918 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
1919 {
1920         u64 extra_flags = flags & (BTRFS_BLOCK_GROUP_RAID0 |
1921                                    BTRFS_BLOCK_GROUP_RAID1 |
1922                                    BTRFS_BLOCK_GROUP_RAID10 |
1923                                    BTRFS_BLOCK_GROUP_DUP);
1924         if (extra_flags) {
1925                 if (flags & BTRFS_BLOCK_GROUP_DATA)
1926                         fs_info->avail_data_alloc_bits |= extra_flags;
1927                 if (flags & BTRFS_BLOCK_GROUP_METADATA)
1928                         fs_info->avail_metadata_alloc_bits |= extra_flags;
1929                 if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
1930                         fs_info->avail_system_alloc_bits |= extra_flags;
1931         }
1932 }
1933
1934 static void set_block_group_readonly(struct btrfs_block_group_cache *cache)
1935 {
1936         spin_lock(&cache->space_info->lock);
1937         spin_lock(&cache->lock);
1938         if (!cache->ro) {
1939                 cache->space_info->bytes_readonly += cache->key.offset -
1940                                         btrfs_block_group_used(&cache->item);
1941                 cache->ro = 1;
1942         }
1943         spin_unlock(&cache->lock);
1944         spin_unlock(&cache->space_info->lock);
1945 }
1946
1947 u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
1948 {
1949         u64 num_devices = root->fs_info->fs_devices->rw_devices;
1950
1951         if (num_devices == 1)
1952                 flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
1953         if (num_devices < 4)
1954                 flags &= ~BTRFS_BLOCK_GROUP_RAID10;
1955
1956         if ((flags & BTRFS_BLOCK_GROUP_DUP) &&
1957             (flags & (BTRFS_BLOCK_GROUP_RAID1 |
1958                       BTRFS_BLOCK_GROUP_RAID10))) {
1959                 flags &= ~BTRFS_BLOCK_GROUP_DUP;
1960         }
1961
1962         if ((flags & BTRFS_BLOCK_GROUP_RAID1) &&
1963             (flags & BTRFS_BLOCK_GROUP_RAID10)) {
1964                 flags &= ~BTRFS_BLOCK_GROUP_RAID1;
1965         }
1966
1967         if ((flags & BTRFS_BLOCK_GROUP_RAID0) &&
1968             ((flags & BTRFS_BLOCK_GROUP_RAID1) |
1969              (flags & BTRFS_BLOCK_GROUP_RAID10) |
1970              (flags & BTRFS_BLOCK_GROUP_DUP)))
1971                 flags &= ~BTRFS_BLOCK_GROUP_RAID0;
1972         return flags;
1973 }
1974
1975 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
1976                           struct btrfs_root *extent_root, u64 alloc_bytes,
1977                           u64 flags, int force)
1978 {
1979         struct btrfs_space_info *space_info;
1980         u64 thresh;
1981         int ret = 0;
1982
1983         mutex_lock(&extent_root->fs_info->chunk_mutex);
1984
1985         flags = btrfs_reduce_alloc_profile(extent_root, flags);
1986
1987         space_info = __find_space_info(extent_root->fs_info, flags);
1988         if (!space_info) {
1989                 ret = update_space_info(extent_root->fs_info, flags,
1990                                         0, 0, &space_info);
1991                 BUG_ON(ret);
1992         }
1993         BUG_ON(!space_info);
1994
1995         spin_lock(&space_info->lock);
1996         if (space_info->force_alloc) {
1997                 force = 1;
1998                 space_info->force_alloc = 0;
1999         }
2000         if (space_info->full) {
2001                 spin_unlock(&space_info->lock);
2002                 goto out;
2003         }
2004
2005         thresh = space_info->total_bytes - space_info->bytes_readonly;
2006         thresh = div_factor(thresh, 6);
2007         if (!force &&
2008            (space_info->bytes_used + space_info->bytes_pinned +
2009             space_info->bytes_reserved + alloc_bytes) < thresh) {
2010                 spin_unlock(&space_info->lock);
2011                 goto out;
2012         }
2013         spin_unlock(&space_info->lock);
2014
2015         ret = btrfs_alloc_chunk(trans, extent_root, flags);
2016         if (ret)
2017                 space_info->full = 1;
2018 out:
2019         mutex_unlock(&extent_root->fs_info->chunk_mutex);
2020         return ret;
2021 }
2022
2023 static int update_block_group(struct btrfs_trans_handle *trans,
2024                               struct btrfs_root *root,
2025                               u64 bytenr, u64 num_bytes, int alloc,
2026                               int mark_free)
2027 {
2028         struct btrfs_block_group_cache *cache;
2029         struct btrfs_fs_info *info = root->fs_info;
2030         u64 total = num_bytes;
2031         u64 old_val;
2032         u64 byte_in_group;
2033
2034         while (total) {
2035                 cache = btrfs_lookup_block_group(info, bytenr);
2036                 if (!cache)
2037                         return -1;
2038                 byte_in_group = bytenr - cache->key.objectid;
2039                 WARN_ON(byte_in_group > cache->key.offset);
2040
2041                 spin_lock(&cache->space_info->lock);
2042                 spin_lock(&cache->lock);
2043                 cache->dirty = 1;
2044                 old_val = btrfs_block_group_used(&cache->item);
2045                 num_bytes = min(total, cache->key.offset - byte_in_group);
2046                 if (alloc) {
2047                         old_val += num_bytes;
2048                         cache->space_info->bytes_used += num_bytes;
2049                         if (cache->ro)
2050                                 cache->space_info->bytes_readonly -= num_bytes;
2051                         btrfs_set_block_group_used(&cache->item, old_val);
2052                         spin_unlock(&cache->lock);
2053                         spin_unlock(&cache->space_info->lock);
2054                 } else {
2055                         old_val -= num_bytes;
2056                         cache->space_info->bytes_used -= num_bytes;
2057                         if (cache->ro)
2058                                 cache->space_info->bytes_readonly += num_bytes;
2059                         btrfs_set_block_group_used(&cache->item, old_val);
2060                         spin_unlock(&cache->lock);
2061                         spin_unlock(&cache->space_info->lock);
2062                         if (mark_free) {
2063                                 int ret;
2064
2065                                 ret = btrfs_discard_extent(root, bytenr,
2066                                                            num_bytes);
2067                                 WARN_ON(ret);
2068
2069                                 ret = btrfs_add_free_space(cache, bytenr,
2070                                                            num_bytes);
2071                                 WARN_ON(ret);
2072                         }
2073                 }
2074                 put_block_group(cache);
2075                 total -= num_bytes;
2076                 bytenr += num_bytes;
2077         }
2078         return 0;
2079 }
2080
2081 static u64 first_logical_byte(struct btrfs_root *root, u64 search_start)
2082 {
2083         struct btrfs_block_group_cache *cache;
2084         u64 bytenr;
2085
2086         cache = btrfs_lookup_first_block_group(root->fs_info, search_start);
2087         if (!cache)
2088                 return 0;
2089
2090         bytenr = cache->key.objectid;
2091         put_block_group(cache);
2092
2093         return bytenr;
2094 }
2095
2096 int btrfs_update_pinned_extents(struct btrfs_root *root,
2097                                 u64 bytenr, u64 num, int pin)
2098 {
2099         u64 len;
2100         struct btrfs_block_group_cache *cache;
2101         struct btrfs_fs_info *fs_info = root->fs_info;
2102
2103         WARN_ON(!mutex_is_locked(&root->fs_info->pinned_mutex));
2104         if (pin) {
2105                 set_extent_dirty(&fs_info->pinned_extents,
2106                                 bytenr, bytenr + num - 1, GFP_NOFS);
2107         } else {
2108                 clear_extent_dirty(&fs_info->pinned_extents,
2109                                 bytenr, bytenr + num - 1, GFP_NOFS);
2110         }
2111         while (num > 0) {
2112                 cache = btrfs_lookup_block_group(fs_info, bytenr);
2113                 BUG_ON(!cache);
2114                 len = min(num, cache->key.offset -
2115                           (bytenr - cache->key.objectid));
2116                 if (pin) {
2117                         spin_lock(&cache->space_info->lock);
2118                         spin_lock(&cache->lock);
2119                         cache->pinned += len;
2120                         cache->space_info->bytes_pinned += len;
2121                         spin_unlock(&cache->lock);
2122                         spin_unlock(&cache->space_info->lock);
2123                         fs_info->total_pinned += len;
2124                 } else {
2125                         spin_lock(&cache->space_info->lock);
2126                         spin_lock(&cache->lock);
2127                         cache->pinned -= len;
2128                         cache->space_info->bytes_pinned -= len;
2129                         spin_unlock(&cache->lock);
2130                         spin_unlock(&cache->space_info->lock);
2131                         fs_info->total_pinned -= len;
2132                         if (cache->cached)
2133                                 btrfs_add_free_space(cache, bytenr, len);
2134                 }
2135                 put_block_group(cache);
2136                 bytenr += len;
2137                 num -= len;
2138         }
2139         return 0;
2140 }
2141
2142 static int update_reserved_extents(struct btrfs_root *root,
2143                                    u64 bytenr, u64 num, int reserve)
2144 {
2145         u64 len;
2146         struct btrfs_block_group_cache *cache;
2147         struct btrfs_fs_info *fs_info = root->fs_info;
2148
2149         while (num > 0) {
2150                 cache = btrfs_lookup_block_group(fs_info, bytenr);
2151                 BUG_ON(!cache);
2152                 len = min(num, cache->key.offset -
2153                           (bytenr - cache->key.objectid));
2154
2155                 spin_lock(&cache->space_info->lock);
2156                 spin_lock(&cache->lock);
2157                 if (reserve) {
2158                         cache->reserved += len;
2159                         cache->space_info->bytes_reserved += len;
2160                 } else {
2161                         cache->reserved -= len;
2162                         cache->space_info->bytes_reserved -= len;
2163                 }
2164                 spin_unlock(&cache->lock);
2165                 spin_unlock(&cache->space_info->lock);
2166                 put_block_group(cache);
2167                 bytenr += len;
2168                 num -= len;
2169         }
2170         return 0;
2171 }
2172
2173 int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy)
2174 {
2175         u64 last = 0;
2176         u64 start;
2177         u64 end;
2178         struct extent_io_tree *pinned_extents = &root->fs_info->pinned_extents;
2179         int ret;
2180
2181         mutex_lock(&root->fs_info->pinned_mutex);
2182         while (1) {
2183                 ret = find_first_extent_bit(pinned_extents, last,
2184                                             &start, &end, EXTENT_DIRTY);
2185                 if (ret)
2186                         break;
2187                 set_extent_dirty(copy, start, end, GFP_NOFS);
2188                 last = end + 1;
2189         }
2190         mutex_unlock(&root->fs_info->pinned_mutex);
2191         return 0;
2192 }
2193
2194 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
2195                                struct btrfs_root *root,
2196                                struct extent_io_tree *unpin)
2197 {
2198         u64 start;
2199         u64 end;
2200         int ret;
2201
2202         mutex_lock(&root->fs_info->pinned_mutex);
2203         while (1) {
2204                 ret = find_first_extent_bit(unpin, 0, &start, &end,
2205                                             EXTENT_DIRTY);
2206                 if (ret)
2207                         break;
2208
2209                 ret = btrfs_discard_extent(root, start, end + 1 - start);
2210
2211                 btrfs_update_pinned_extents(root, start, end + 1 - start, 0);
2212                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
2213
2214                 if (need_resched()) {
2215                         mutex_unlock(&root->fs_info->pinned_mutex);
2216                         cond_resched();
2217                         mutex_lock(&root->fs_info->pinned_mutex);
2218                 }
2219         }
2220         mutex_unlock(&root->fs_info->pinned_mutex);
2221         return ret;
2222 }
2223
2224 static int finish_current_insert(struct btrfs_trans_handle *trans,
2225                                  struct btrfs_root *extent_root, int all)
2226 {
2227         u64 start;
2228         u64 end;
2229         u64 priv;
2230         u64 search = 0;
2231         struct btrfs_fs_info *info = extent_root->fs_info;
2232         struct btrfs_path *path;
2233         struct pending_extent_op *extent_op, *tmp;
2234         struct list_head insert_list, update_list;
2235         int ret;
2236         int num_inserts = 0, max_inserts, restart = 0;
2237
2238         path = btrfs_alloc_path();
2239         INIT_LIST_HEAD(&insert_list);
2240         INIT_LIST_HEAD(&update_list);
2241
2242         max_inserts = extent_root->leafsize /
2243                 (2 * sizeof(struct btrfs_key) + 2 * sizeof(struct btrfs_item) +
2244                  sizeof(struct btrfs_extent_ref) +
2245                  sizeof(struct btrfs_extent_item));
2246 again:
2247         mutex_lock(&info->extent_ins_mutex);
2248         while (1) {
2249                 ret = find_first_extent_bit(&info->extent_ins, search, &start,
2250                                             &end, EXTENT_WRITEBACK);
2251                 if (ret) {
2252                         if (restart && !num_inserts &&
2253                             list_empty(&update_list)) {
2254                                 restart = 0;
2255                                 search = 0;
2256                                 continue;
2257                         }
2258                         break;
2259                 }
2260
2261                 ret = try_lock_extent(&info->extent_ins, start, end, GFP_NOFS);
2262                 if (!ret) {
2263                         if (all)
2264                                 restart = 1;
2265                         search = end + 1;
2266                         if (need_resched()) {
2267                                 mutex_unlock(&info->extent_ins_mutex);
2268                                 cond_resched();
2269                                 mutex_lock(&info->extent_ins_mutex);
2270                         }
2271                         continue;
2272                 }
2273
2274                 ret = get_state_private(&info->extent_ins, start, &priv);
2275                 BUG_ON(ret);
2276                 extent_op = (struct pending_extent_op *)(unsigned long) priv;
2277
2278                 if (extent_op->type == PENDING_EXTENT_INSERT) {
2279                         num_inserts++;
2280                         list_add_tail(&extent_op->list, &insert_list);
2281                         search = end + 1;
2282                         if (num_inserts == max_inserts) {
2283                                 restart = 1;
2284                                 break;
2285                         }
2286                 } else if (extent_op->type == PENDING_BACKREF_UPDATE) {
2287                         list_add_tail(&extent_op->list, &update_list);
2288                         search = end + 1;
2289                 } else {
2290                         BUG();
2291                 }
2292         }
2293
2294         /*
2295          * process the update list, clear the writeback bit for it, and if
2296          * somebody marked this thing for deletion then just unlock it and be
2297          * done, the free_extents will handle it
2298          */
2299         list_for_each_entry_safe(extent_op, tmp, &update_list, list) {
2300                 clear_extent_bits(&info->extent_ins, extent_op->bytenr,
2301                                   extent_op->bytenr + extent_op->num_bytes - 1,
2302                                   EXTENT_WRITEBACK, GFP_NOFS);
2303                 if (extent_op->del) {
2304                         list_del_init(&extent_op->list);
2305                         unlock_extent(&info->extent_ins, extent_op->bytenr,
2306                                       extent_op->bytenr + extent_op->num_bytes
2307                                       - 1, GFP_NOFS);
2308                         kfree(extent_op);
2309                 }
2310         }
2311         mutex_unlock(&info->extent_ins_mutex);
2312
2313         /*
2314          * still have things left on the update list, go ahead an update
2315          * everything
2316          */
2317         if (!list_empty(&update_list)) {
2318                 ret = update_backrefs(trans, extent_root, path, &update_list);
2319                 BUG_ON(ret);
2320
2321                 /* we may have COW'ed new blocks, so lets start over */
2322                 if (all)
2323                         restart = 1;
2324         }
2325
2326         /*
2327          * if no inserts need to be done, but we skipped some extents and we
2328          * need to make sure everything is cleaned then reset everything and
2329          * go back to the beginning
2330          */
2331         if (!num_inserts && restart) {
2332                 search = 0;
2333                 restart = 0;
2334                 INIT_LIST_HEAD(&update_list);
2335                 INIT_LIST_HEAD(&insert_list);
2336                 goto again;
2337         } else if (!num_inserts) {
2338                 goto out;
2339         }
2340
2341         /*
2342          * process the insert extents list.  Again if we are deleting this
2343          * extent, then just unlock it, pin down the bytes if need be, and be
2344          * done with it.  Saves us from having to actually insert the extent
2345          * into the tree and then subsequently come along and delete it
2346          */
2347         mutex_lock(&info->extent_ins_mutex);
2348         list_for_each_entry_safe(extent_op, tmp, &insert_list, list) {
2349                 clear_extent_bits(&info->extent_ins, extent_op->bytenr,
2350                                   extent_op->bytenr + extent_op->num_bytes - 1,
2351                                   EXTENT_WRITEBACK, GFP_NOFS);
2352                 if (extent_op->del) {
2353                         u64 used;
2354                         list_del_init(&extent_op->list);
2355                         unlock_extent(&info->extent_ins, extent_op->bytenr,
2356                                       extent_op->bytenr + extent_op->num_bytes
2357                                       - 1, GFP_NOFS);
2358
2359                         mutex_lock(&extent_root->fs_info->pinned_mutex);
2360                         ret = pin_down_bytes(trans, extent_root,
2361                                              extent_op->bytenr,
2362                                              extent_op->num_bytes, 0);
2363                         mutex_unlock(&extent_root->fs_info->pinned_mutex);
2364
2365                         spin_lock(&info->delalloc_lock);
2366                         used = btrfs_super_bytes_used(&info->super_copy);
2367                         btrfs_set_super_bytes_used(&info->super_copy,
2368                                         used - extent_op->num_bytes);
2369                         used = btrfs_root_used(&extent_root->root_item);
2370                         btrfs_set_root_used(&extent_root->root_item,
2371                                         used - extent_op->num_bytes);
2372                         spin_unlock(&info->delalloc_lock);
2373
2374                         ret = update_block_group(trans, extent_root,
2375                                                  extent_op->bytenr,
2376                                                  extent_op->num_bytes,
2377                                                  0, ret > 0);
2378                         BUG_ON(ret);
2379                         kfree(extent_op);
2380                         num_inserts--;
2381                 }
2382         }
2383         mutex_unlock(&info->extent_ins_mutex);
2384
2385         ret = insert_extents(trans, extent_root, path, &insert_list,
2386                              num_inserts);
2387         BUG_ON(ret);
2388
2389         /*
2390          * if restart is set for whatever reason we need to go back and start
2391          * searching through the pending list again.
2392          *
2393          * We just inserted some extents, which could have resulted in new
2394          * blocks being allocated, which would result in new blocks needing
2395          * updates, so if all is set we _must_ restart to get the updated
2396          * blocks.
2397          */
2398         if (restart || all) {
2399                 INIT_LIST_HEAD(&insert_list);
2400                 INIT_LIST_HEAD(&update_list);
2401                 search = 0;
2402                 restart = 0;
2403                 num_inserts = 0;
2404                 goto again;
2405         }
2406 out:
2407         btrfs_free_path(path);
2408         return 0;
2409 }
2410
2411 static int pin_down_bytes(struct btrfs_trans_handle *trans,
2412                           struct btrfs_root *root,
2413                           u64 bytenr, u64 num_bytes, int is_data)
2414 {
2415         int err = 0;
2416         struct extent_buffer *buf;
2417
2418         if (is_data)
2419                 goto pinit;
2420
2421         buf = btrfs_find_tree_block(root, bytenr, num_bytes);
2422         if (!buf)
2423                 goto pinit;
2424
2425         /* we can reuse a block if it hasn't been written
2426          * and it is from this transaction.  We can't
2427          * reuse anything from the tree log root because
2428          * it has tiny sub-transactions.
2429          */
2430         if (btrfs_buffer_uptodate(buf, 0) &&
2431             btrfs_try_tree_lock(buf)) {
2432                 u64 header_owner = btrfs_header_owner(buf);
2433                 u64 header_transid = btrfs_header_generation(buf);
2434                 if (header_owner != BTRFS_TREE_LOG_OBJECTID &&
2435                     header_owner != BTRFS_TREE_RELOC_OBJECTID &&
2436                     header_transid == trans->transid &&
2437                     !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
2438                         clean_tree_block(NULL, root, buf);
2439                         btrfs_tree_unlock(buf);
2440                         free_extent_buffer(buf);
2441                         return 1;
2442                 }
2443                 btrfs_tree_unlock(buf);
2444         }
2445         free_extent_buffer(buf);
2446 pinit:
2447         btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
2448
2449         BUG_ON(err < 0);
2450         return 0;
2451 }
2452
2453 /*
2454  * remove an extent from the root, returns 0 on success
2455  */
2456 static int __free_extent(struct btrfs_trans_handle *trans,
2457                          struct btrfs_root *root,
2458                          u64 bytenr, u64 num_bytes, u64 parent,
2459                          u64 root_objectid, u64 ref_generation,
2460                          u64 owner_objectid, int pin, int mark_free)
2461 {
2462         struct btrfs_path *path;
2463         struct btrfs_key key;
2464         struct btrfs_fs_info *info = root->fs_info;
2465         struct btrfs_root *extent_root = info->extent_root;
2466         struct extent_buffer *leaf;
2467         int ret;
2468         int extent_slot = 0;
2469         int found_extent = 0;
2470         int num_to_del = 1;
2471         struct btrfs_extent_item *ei;
2472         u32 refs;
2473
2474         key.objectid = bytenr;
2475         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
2476         key.offset = num_bytes;
2477         path = btrfs_alloc_path();
2478         if (!path)
2479                 return -ENOMEM;
2480
2481         path->reada = 1;
2482         ret = lookup_extent_backref(trans, extent_root, path,
2483                                     bytenr, parent, root_objectid,
2484                                     ref_generation, owner_objectid, 1);
2485         if (ret == 0) {
2486                 struct btrfs_key found_key;
2487                 extent_slot = path->slots[0];
2488                 while (extent_slot > 0) {
2489                         extent_slot--;
2490                         btrfs_item_key_to_cpu(path->nodes[0], &found_key,
2491                                               extent_slot);
2492                         if (found_key.objectid != bytenr)
2493                                 break;
2494                         if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
2495                             found_key.offset == num_bytes) {
2496                                 found_extent = 1;
2497                                 break;
2498                         }
2499                         if (path->slots[0] - extent_slot > 5)
2500                                 break;
2501                 }
2502                 if (!found_extent) {
2503                         ret = remove_extent_backref(trans, extent_root, path);
2504                         BUG_ON(ret);
2505                         btrfs_release_path(extent_root, path);
2506                         ret = btrfs_search_slot(trans, extent_root,
2507                                                 &key, path, -1, 1);
2508                         if (ret) {
2509                                 printk(KERN_ERR "umm, got %d back from search"
2510                                        ", was looking for %llu\n", ret,
2511                                        (unsigned long long)bytenr);
2512                                 btrfs_print_leaf(extent_root, path->nodes[0]);
2513                         }
2514                         BUG_ON(ret);
2515                         extent_slot = path->slots[0];
2516                 }
2517         } else {
2518                 btrfs_print_leaf(extent_root, path->nodes[0]);
2519                 WARN_ON(1);
2520                 printk(KERN_ERR "btrfs unable to find ref byte nr %llu "
2521                        "root %llu gen %llu owner %llu\n",
2522                        (unsigned long long)bytenr,
2523                        (unsigned long long)root_objectid,
2524                        (unsigned long long)ref_generation,
2525                        (unsigned long long)owner_objectid);
2526         }
2527
2528         leaf = path->nodes[0];
2529         ei = btrfs_item_ptr(leaf, extent_slot,
2530                             struct btrfs_extent_item);
2531         refs = btrfs_extent_refs(leaf, ei);
2532         BUG_ON(refs == 0);
2533         refs -= 1;
2534         btrfs_set_extent_refs(leaf, ei, refs);
2535
2536         btrfs_mark_buffer_dirty(leaf);
2537
2538         if (refs == 0 && found_extent && path->slots[0] == extent_slot + 1) {
2539                 struct btrfs_extent_ref *ref;
2540                 ref = btrfs_item_ptr(leaf, path->slots[0],
2541                                      struct btrfs_extent_ref);
2542                 BUG_ON(btrfs_ref_num_refs(leaf, ref) != 1);
2543                 /* if the back ref and the extent are next to each other
2544                  * they get deleted below in one shot
2545                  */
2546                 path->slots[0] = extent_slot;
2547                 num_to_del = 2;
2548         } else if (found_extent) {
2549                 /* otherwise delete the extent back ref */
2550                 ret = remove_extent_backref(trans, extent_root, path);
2551                 BUG_ON(ret);
2552                 /* if refs are 0, we need to setup the path for deletion */
2553                 if (refs == 0) {
2554                         btrfs_release_path(extent_root, path);
2555                         ret = btrfs_search_slot(trans, extent_root, &key, path,
2556                                                 -1, 1);
2557                         BUG_ON(ret);
2558                 }
2559         }
2560
2561         if (refs == 0) {
2562                 u64 super_used;
2563                 u64 root_used;
2564
2565                 if (pin) {
2566                         mutex_lock(&root->fs_info->pinned_mutex);
2567                         ret = pin_down_bytes(trans, root, bytenr, num_bytes,
2568                                 owner_objectid >= BTRFS_FIRST_FREE_OBJECTID);
2569                         mutex_unlock(&root->fs_info->pinned_mutex);
2570                         if (ret > 0)
2571                                 mark_free = 1;
2572                         BUG_ON(ret < 0);
2573                 }
2574                 /* block accounting for super block */
2575                 spin_lock(&info->delalloc_lock);
2576                 super_used = btrfs_super_bytes_used(&info->super_copy);
2577                 btrfs_set_super_bytes_used(&info->super_copy,
2578                                            super_used - num_bytes);
2579
2580                 /* block accounting for root item */
2581                 root_used = btrfs_root_used(&root->root_item);
2582                 btrfs_set_root_used(&root->root_item,
2583                                            root_used - num_bytes);
2584                 spin_unlock(&info->delalloc_lock);
2585                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
2586                                       num_to_del);
2587                 BUG_ON(ret);
2588                 btrfs_release_path(extent_root, path);
2589
2590                 if (owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
2591                         ret = btrfs_del_csums(trans, root, bytenr, num_bytes);
2592                         BUG_ON(ret);
2593                 }
2594
2595                 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
2596                                          mark_free);
2597                 BUG_ON(ret);
2598         }
2599         btrfs_free_path(path);
2600         finish_current_insert(trans, extent_root, 0);
2601         return ret;
2602 }
2603
2604 /*
2605  * find all the blocks marked as pending in the radix tree and remove
2606  * them from the extent map
2607  */
2608 static int del_pending_extents(struct btrfs_trans_handle *trans,
2609                                struct btrfs_root *extent_root, int all)
2610 {
2611         int ret;
2612         int err = 0;
2613         u64 start;
2614         u64 end;
2615         u64 priv;
2616         u64 search = 0;
2617         int nr = 0, skipped = 0;
2618         struct extent_io_tree *pending_del;
2619         struct extent_io_tree *extent_ins;
2620         struct pending_extent_op *extent_op;
2621         struct btrfs_fs_info *info = extent_root->fs_info;
2622         struct list_head delete_list;
2623
2624         INIT_LIST_HEAD(&delete_list);
2625         extent_ins = &extent_root->fs_info->extent_ins;
2626         pending_del = &extent_root->fs_info->pending_del;
2627
2628 again:
2629         mutex_lock(&info->extent_ins_mutex);
2630         while (1) {
2631                 ret = find_first_extent_bit(pending_del, search, &start, &end,
2632                                             EXTENT_WRITEBACK);
2633                 if (ret) {
2634                         if (all && skipped && !nr) {
2635                                 search = 0;
2636                                 skipped = 0;
2637                                 continue;
2638                         }
2639                         mutex_unlock(&info->extent_ins_mutex);
2640                         break;
2641                 }
2642
2643                 ret = try_lock_extent(extent_ins, start, end, GFP_NOFS);
2644                 if (!ret) {
2645                         search = end+1;
2646                         skipped = 1;
2647
2648                         if (need_resched()) {
2649                                 mutex_unlock(&info->extent_ins_mutex);
2650                                 cond_resched();
2651                                 mutex_lock(&info->extent_ins_mutex);
2652                         }
2653
2654                         continue;
2655                 }
2656                 BUG_ON(ret < 0);
2657
2658                 ret = get_state_private(pending_del, start, &priv);
2659                 BUG_ON(ret);
2660                 extent_op = (struct pending_extent_op *)(unsigned long)priv;
2661
2662                 clear_extent_bits(pending_del, start, end, EXTENT_WRITEBACK,
2663                                   GFP_NOFS);
2664                 if (!test_range_bit(extent_ins, start, end,
2665                                     EXTENT_WRITEBACK, 0)) {
2666                         list_add_tail(&extent_op->list, &delete_list);
2667                         nr++;
2668                 } else {
2669                         kfree(extent_op);
2670
2671                         ret = get_state_private(&info->extent_ins, start,
2672                                                 &priv);
2673                         BUG_ON(ret);
2674                         extent_op = (struct pending_extent_op *)
2675                                                 (unsigned long)priv;
2676
2677                         clear_extent_bits(&info->extent_ins, start, end,
2678                                           EXTENT_WRITEBACK, GFP_NOFS);
2679
2680                         if (extent_op->type == PENDING_BACKREF_UPDATE) {
2681                                 list_add_tail(&extent_op->list, &delete_list);
2682                                 search = end + 1;
2683                                 nr++;
2684                                 continue;
2685                         }
2686
2687                         mutex_lock(&extent_root->fs_info->pinned_mutex);
2688                         ret = pin_down_bytes(trans, extent_root, start,
2689                                              end + 1 - start, 0);
2690                         mutex_unlock(&extent_root->fs_info->pinned_mutex);
2691
2692                         ret = update_block_group(trans, extent_root, start,
2693                                                 end + 1 - start, 0, ret > 0);
2694
2695                         unlock_extent(extent_ins, start, end, GFP_NOFS);
2696                         BUG_ON(ret);
2697                         kfree(extent_op);
2698                 }
2699                 if (ret)
2700                         err = ret;
2701
2702                 search = end + 1;
2703
2704                 if (need_resched()) {
2705                         mutex_unlock(&info->extent_ins_mutex);
2706                         cond_resched();
2707                         mutex_lock(&info->extent_ins_mutex);
2708                 }
2709         }
2710
2711         if (nr) {
2712                 ret = free_extents(trans, extent_root, &delete_list);
2713                 BUG_ON(ret);
2714         }
2715
2716         if (all && skipped) {
2717                 INIT_LIST_HEAD(&delete_list);
2718                 search = 0;
2719                 nr = 0;
2720                 goto again;
2721         }
2722
2723         if (!err)
2724                 finish_current_insert(trans, extent_root, 0);
2725         return err;
2726 }
2727
2728 /*
2729  * remove an extent from the root, returns 0 on success
2730  */
2731 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
2732                                struct btrfs_root *root,
2733                                u64 bytenr, u64 num_bytes, u64 parent,
2734                                u64 root_objectid, u64 ref_generation,
2735                                u64 owner_objectid, int pin)
2736 {
2737         struct btrfs_root *extent_root = root->fs_info->extent_root;
2738         int pending_ret;
2739         int ret;
2740
2741         WARN_ON(num_bytes < root->sectorsize);
2742         if (root == extent_root) {
2743                 struct pending_extent_op *extent_op = NULL;
2744
2745                 mutex_lock(&root->fs_info->extent_ins_mutex);
2746                 if (test_range_bit(&root->fs_info->extent_ins, bytenr,
2747                                 bytenr + num_bytes - 1, EXTENT_WRITEBACK, 0)) {
2748                         u64 priv;
2749                         ret = get_state_private(&root->fs_info->extent_ins,
2750                                                 bytenr, &priv);
2751                         BUG_ON(ret);
2752                         extent_op = (struct pending_extent_op *)
2753                                                 (unsigned long)priv;
2754
2755                         extent_op->del = 1;
2756                         if (extent_op->type == PENDING_EXTENT_INSERT) {
2757                                 mutex_unlock(&root->fs_info->extent_ins_mutex);
2758                                 return 0;
2759                         }
2760                 }
2761
2762                 if (extent_op) {
2763                         ref_generation = extent_op->orig_generation;
2764                         parent = extent_op->orig_parent;
2765                 }
2766
2767                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
2768                 BUG_ON(!extent_op);
2769
2770                 extent_op->type = PENDING_EXTENT_DELETE;
2771                 extent_op->bytenr = bytenr;
2772                 extent_op->num_bytes = num_bytes;
2773                 extent_op->parent = parent;
2774                 extent_op->orig_parent = parent;
2775                 extent_op->generation = ref_generation;
2776                 extent_op->orig_generation = ref_generation;
2777                 extent_op->level = (int)owner_objectid;
2778                 INIT_LIST_HEAD(&extent_op->list);
2779                 extent_op->del = 0;
2780
2781                 set_extent_bits(&root->fs_info->pending_del,
2782                                 bytenr, bytenr + num_bytes - 1,
2783                                 EXTENT_WRITEBACK, GFP_NOFS);
2784                 set_state_private(&root->fs_info->pending_del,
2785                                   bytenr, (unsigned long)extent_op);
2786                 mutex_unlock(&root->fs_info->extent_ins_mutex);
2787                 return 0;
2788         }
2789         /* if metadata always pin */
2790         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
2791                 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
2792                         mutex_lock(&root->fs_info->pinned_mutex);
2793                         btrfs_update_pinned_extents(root, bytenr, num_bytes, 1);
2794                         mutex_unlock(&root->fs_info->pinned_mutex);
2795                         update_reserved_extents(root, bytenr, num_bytes, 0);
2796                         return 0;
2797                 }
2798                 pin = 1;
2799         }
2800
2801         /* if data pin when any transaction has committed this */
2802         if (ref_generation != trans->transid)
2803                 pin = 1;
2804
2805         ret = __free_extent(trans, root, bytenr, num_bytes, parent,
2806                             root_objectid, ref_generation,
2807                             owner_objectid, pin, pin == 0);
2808
2809         finish_current_insert(trans, root->fs_info->extent_root, 0);
2810         pending_ret = del_pending_extents(trans, root->fs_info->extent_root, 0);
2811         return ret ? ret : pending_ret;
2812 }
2813
2814 int btrfs_free_extent(struct btrfs_trans_handle *trans,
2815                       struct btrfs_root *root,
2816                       u64 bytenr, u64 num_bytes, u64 parent,
2817                       u64 root_objectid, u64 ref_generation,
2818                       u64 owner_objectid, int pin)
2819 {
2820         int ret;
2821
2822         ret = __btrfs_free_extent(trans, root, bytenr, num_bytes, parent,
2823                                   root_objectid, ref_generation,
2824                                   owner_objectid, pin);
2825         return ret;
2826 }
2827
2828 static u64 stripe_align(struct btrfs_root *root, u64 val)
2829 {
2830         u64 mask = ((u64)root->stripesize - 1);
2831         u64 ret = (val + mask) & ~mask;
2832         return ret;
2833 }
2834
2835 /*
2836  * walks the btree of allocated extents and find a hole of a given size.
2837  * The key ins is changed to record the hole:
2838  * ins->objectid == block start
2839  * ins->flags = BTRFS_EXTENT_ITEM_KEY
2840  * ins->offset == number of blocks
2841  * Any available blocks before search_start are skipped.
2842  */
2843 static noinline int find_free_extent(struct btrfs_trans_handle *trans,
2844                                      struct btrfs_root *orig_root,
2845                                      u64 num_bytes, u64 empty_size,
2846                                      u64 search_start, u64 search_end,
2847                                      u64 hint_byte, struct btrfs_key *ins,
2848                                      u64 exclude_start, u64 exclude_nr,
2849                                      int data)
2850 {
2851         int ret = 0;
2852         struct btrfs_root *root = orig_root->fs_info->extent_root;
2853         u64 total_needed = num_bytes;
2854         u64 *last_ptr = NULL;
2855         u64 last_wanted = 0;
2856         struct btrfs_block_group_cache *block_group = NULL;
2857         int chunk_alloc_done = 0;
2858         int empty_cluster = 2 * 1024 * 1024;
2859         int allowed_chunk_alloc = 0;
2860         struct list_head *head = NULL, *cur = NULL;
2861         int loop = 0;
2862         int extra_loop = 0;
2863         struct btrfs_space_info *space_info;
2864
2865         WARN_ON(num_bytes < root->sectorsize);
2866         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
2867         ins->objectid = 0;
2868         ins->offset = 0;
2869
2870         if (orig_root->ref_cows || empty_size)
2871                 allowed_chunk_alloc = 1;
2872
2873         if (data & BTRFS_BLOCK_GROUP_METADATA) {
2874                 last_ptr = &root->fs_info->last_alloc;
2875                 if (!btrfs_test_opt(root, SSD))
2876                         empty_cluster = 64 * 1024;
2877         }
2878
2879         if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD))
2880                 last_ptr = &root->fs_info->last_data_alloc;
2881
2882         if (last_ptr) {
2883                 if (*last_ptr) {
2884                         hint_byte = *last_ptr;
2885                         last_wanted = *last_ptr;
2886                 } else
2887                         empty_size += empty_cluster;
2888         } else {
2889                 empty_cluster = 0;
2890         }
2891         search_start = max(search_start, first_logical_byte(root, 0));
2892         search_start = max(search_start, hint_byte);
2893
2894         if (last_wanted && search_start != last_wanted) {
2895                 last_wanted = 0;
2896                 empty_size += empty_cluster;
2897         }
2898
2899         total_needed += empty_size;
2900         block_group = btrfs_lookup_block_group(root->fs_info, search_start);
2901         if (!block_group)
2902                 block_group = btrfs_lookup_first_block_group(root->fs_info,
2903                                                              search_start);
2904         space_info = __find_space_info(root->fs_info, data);
2905
2906         down_read(&space_info->groups_sem);
2907         while (1) {
2908                 struct btrfs_free_space *free_space;
2909                 /*
2910                  * the only way this happens if our hint points to a block
2911                  * group thats not of the proper type, while looping this
2912                  * should never happen
2913                  */
2914                 if (empty_size)
2915                         extra_loop = 1;
2916
2917                 if (!block_group)
2918                         goto new_group_no_lock;
2919
2920                 if (unlikely(!block_group->cached)) {
2921                         mutex_lock(&block_group->cache_mutex);
2922                         ret = cache_block_group(root, block_group);
2923                         mutex_unlock(&block_group->cache_mutex);
2924                         if (ret)
2925                                 break;
2926                 }
2927
2928                 mutex_lock(&block_group->alloc_mutex);
2929                 if (unlikely(!block_group_bits(block_group, data)))
2930                         goto new_group;
2931
2932                 if (unlikely(block_group->ro))
2933                         goto new_group;
2934
2935                 free_space = btrfs_find_free_space(block_group, search_start,
2936                                                    total_needed);
2937                 if (free_space) {
2938                         u64 start = block_group->key.objectid;
2939                         u64 end = block_group->key.objectid +
2940                                 block_group->key.offset;
2941
2942                         search_start = stripe_align(root, free_space->offset);
2943
2944                         /* move on to the next group */
2945                         if (search_start + num_bytes >= search_end)
2946                                 goto new_group;
2947
2948                         /* move on to the next group */
2949                         if (search_start + num_bytes > end)
2950                                 goto new_group;
2951
2952                         if (last_wanted && search_start != last_wanted) {
2953                                 total_needed += empty_cluster;
2954                                 empty_size += empty_cluster;
2955                                 last_wanted = 0;
2956                                 /*
2957                                  * if search_start is still in this block group
2958                                  * then we just re-search this block group
2959                                  */
2960                                 if (search_start >= start &&
2961                                     search_start < end) {
2962                                         mutex_unlock(&block_group->alloc_mutex);
2963                                         continue;
2964                                 }
2965
2966                                 /* else we go to the next block group */
2967                                 goto new_group;
2968                         }
2969
2970                         if (exclude_nr > 0 &&
2971                             (search_start + num_bytes > exclude_start &&
2972                              search_start < exclude_start + exclude_nr)) {
2973                                 search_start = exclude_start + exclude_nr;
2974                                 /*
2975                                  * if search_start is still in this block group
2976                                  * then we just re-search this block group
2977                                  */
2978                                 if (search_start >= start &&
2979                                     search_start < end) {
2980                                         mutex_unlock(&block_group->alloc_mutex);
2981                                         last_wanted = 0;
2982                                         continue;
2983                                 }
2984
2985                                 /* else we go to the next block group */
2986                                 goto new_group;
2987                         }
2988
2989                         ins->objectid = search_start;
2990                         ins->offset = num_bytes;
2991
2992                         btrfs_remove_free_space_lock(block_group, search_start,
2993                                                      num_bytes);
2994                         /* we are all good, lets return */
2995                         mutex_unlock(&block_group->alloc_mutex);
2996                         break;
2997                 }
2998 new_group:
2999                 mutex_unlock(&block_group->alloc_mutex);
3000                 put_block_group(block_group);
3001                 block_group = NULL;
3002 new_group_no_lock:
3003                 /* don't try to compare new allocations against the
3004                  * last allocation any more
3005                  */
3006                 last_wanted = 0;
3007
3008                 /*
3009                  * Here's how this works.
3010                  * loop == 0: we were searching a block group via a hint
3011                  *              and didn't find anything, so we start at
3012                  *              the head of the block groups and keep searching
3013                  * loop == 1: we're searching through all of the block groups
3014                  *              if we hit the head again we have searched
3015                  *              all of the block groups for this space and we
3016                  *              need to try and allocate, if we cant error out.
3017                  * loop == 2: we allocated more space and are looping through
3018                  *              all of the block groups again.
3019                  */
3020                 if (loop == 0) {
3021                         head = &space_info->block_groups;
3022                         cur = head->next;
3023                         loop++;
3024                 } else if (loop == 1 && cur == head) {
3025                         int keep_going;
3026
3027                         /* at this point we give up on the empty_size
3028                          * allocations and just try to allocate the min
3029                          * space.
3030                          *
3031                          * The extra_loop field was set if an empty_size
3032                          * allocation was attempted above, and if this
3033                          * is try we need to try the loop again without
3034                          * the additional empty_size.
3035                          */
3036                         total_needed -= empty_size;
3037                         empty_size = 0;
3038                         keep_going = extra_loop;
3039                         loop++;
3040
3041                         if (allowed_chunk_alloc && !chunk_alloc_done) {
3042                                 up_read(&space_info->groups_sem);
3043                                 ret = do_chunk_alloc(trans, root, num_bytes +
3044                                                      2 * 1024 * 1024, data, 1);
3045                                 down_read(&space_info->groups_sem);
3046                                 if (ret < 0)
3047                                         goto loop_check;
3048                                 head = &space_info->block_groups;
3049                                 /*
3050                                  * we've allocated a new chunk, keep
3051                                  * trying
3052                                  */
3053                                 keep_going = 1;
3054                                 chunk_alloc_done = 1;
3055                         } else if (!allowed_chunk_alloc) {
3056                                 space_info->force_alloc = 1;
3057                         }
3058 loop_check:
3059                         if (keep_going) {
3060                                 cur = head->next;
3061                                 extra_loop = 0;
3062                         } else {
3063                                 break;
3064                         }
3065                 } else if (cur == head) {
3066                         break;
3067                 }
3068
3069                 block_group = list_entry(cur, struct btrfs_block_group_cache,
3070                                          list);
3071                 atomic_inc(&block_group->count);
3072
3073                 search_start = block_group->key.objectid;
3074                 cur = cur->next;
3075         }
3076
3077         /* we found what we needed */
3078         if (ins->objectid) {
3079                 if (!(data & BTRFS_BLOCK_GROUP_DATA))
3080                         trans->block_group = block_group->key.objectid;
3081
3082                 if (last_ptr)
3083                         *last_ptr = ins->objectid + ins->offset;
3084                 ret = 0;
3085         } else if (!ret) {
3086                 printk(KERN_ERR "btrfs searching for %llu bytes, "
3087                        "num_bytes %llu, loop %d, allowed_alloc %d\n",
3088                        (unsigned long long)total_needed,
3089                        (unsigned long long)num_bytes,
3090                        loop, allowed_chunk_alloc);
3091                 ret = -ENOSPC;
3092         }
3093         if (block_group)
3094                 put_block_group(block_group);
3095
3096         up_read(&space_info->groups_sem);
3097         return ret;
3098 }
3099
3100 static void dump_space_info(struct btrfs_space_info *info, u64 bytes)
3101 {
3102         struct btrfs_block_group_cache *cache;
3103
3104         printk(KERN_INFO "space_info has %llu free, is %sfull\n",
3105                (unsigned long long)(info->total_bytes - info->bytes_used -
3106                                     info->bytes_pinned - info->bytes_reserved),
3107                (info->full) ? "" : "not ");
3108
3109         down_read(&info->groups_sem);
3110         list_for_each_entry(cache, &info->block_groups, list) {
3111                 spin_lock(&cache->lock);
3112                 printk(KERN_INFO "block group %llu has %llu bytes, %llu used "
3113                        "%llu pinned %llu reserved\n",
3114                        (unsigned long long)cache->key.objectid,
3115                        (unsigned long long)cache->key.offset,
3116                        (unsigned long long)btrfs_block_group_used(&cache->item),
3117                        (unsigned long long)cache->pinned,
3118                        (unsigned long long)cache->reserved);
3119                 btrfs_dump_free_space(cache, bytes);
3120                 spin_unlock(&cache->lock);
3121         }
3122         up_read(&info->groups_sem);
3123 }
3124
3125 static int __btrfs_reserve_extent(struct btrfs_trans_handle *trans,
3126                                   struct btrfs_root *root,
3127                                   u64 num_bytes, u64 min_alloc_size,
3128                                   u64 empty_size, u64 hint_byte,
3129                                   u64 search_end, struct btrfs_key *ins,
3130                                   u64 data)
3131 {
3132         int ret;
3133         u64 search_start = 0;
3134         u64 alloc_profile;
3135         struct btrfs_fs_info *info = root->fs_info;
3136
3137         if (data) {
3138                 alloc_profile = info->avail_data_alloc_bits &
3139                         info->data_alloc_profile;
3140                 data = BTRFS_BLOCK_GROUP_DATA | alloc_profile;
3141         } else if (root == root->fs_info->chunk_root) {
3142                 alloc_profile = info->avail_system_alloc_bits &
3143                         info->system_alloc_profile;
3144                 data = BTRFS_BLOCK_GROUP_SYSTEM | alloc_profile;
3145         } else {
3146                 alloc_profile = info->avail_metadata_alloc_bits &
3147                         info->metadata_alloc_profile;
3148                 data = BTRFS_BLOCK_GROUP_METADATA | alloc_profile;
3149         }
3150 again:
3151         data = btrfs_reduce_alloc_profile(root, data);
3152         /*
3153          * the only place that sets empty_size is btrfs_realloc_node, which
3154          * is not called recursively on allocations
3155          */
3156         if (empty_size || root->ref_cows) {
3157                 if (!(data & BTRFS_BLOCK_GROUP_METADATA)) {
3158                         ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3159                                      2 * 1024 * 1024,
3160                                      BTRFS_BLOCK_GROUP_METADATA |
3161                                      (info->metadata_alloc_profile &
3162                                       info->avail_metadata_alloc_bits), 0);
3163                 }
3164                 ret = do_chunk_alloc(trans, root->fs_info->extent_root,
3165                                      num_bytes + 2 * 1024 * 1024, data, 0);
3166         }
3167
3168         WARN_ON(num_bytes < root->sectorsize);
3169         ret = find_free_extent(trans, root, num_bytes, empty_size,
3170                                search_start, search_end, hint_byte, ins,
3171                                trans->alloc_exclude_start,
3172                                trans->alloc_exclude_nr, data);
3173
3174         if (ret == -ENOSPC && num_bytes > min_alloc_size) {
3175                 num_bytes = num_bytes >> 1;
3176                 num_bytes = num_bytes & ~(root->sectorsize - 1);
3177                 num_bytes = max(num_bytes, min_alloc_size);
3178                 do_chunk_alloc(trans, root->fs_info->extent_root,
3179                                num_bytes, data, 1);
3180                 goto again;
3181         }
3182         if (ret) {
3183                 struct btrfs_space_info *sinfo;
3184
3185                 sinfo = __find_space_info(root->fs_info, data);
3186                 printk(KERN_ERR "btrfs allocation failed flags %llu, "
3187                        "wanted %llu\n", (unsigned long long)data,
3188                        (unsigned long long)num_bytes);
3189                 dump_space_info(sinfo, num_bytes);
3190                 BUG();
3191         }
3192
3193         return ret;
3194 }
3195
3196 int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len)
3197 {
3198         struct btrfs_block_group_cache *cache;
3199         int ret = 0;
3200
3201         cache = btrfs_lookup_block_group(root->fs_info, start);
3202         if (!cache) {
3203                 printk(KERN_ERR "Unable to find block group for %llu\n",
3204                        (unsigned long long)start);
3205                 return -ENOSPC;
3206         }
3207
3208         ret = btrfs_discard_extent(root, start, len);
3209
3210         btrfs_add_free_space(cache, start, len);
3211         put_block_group(cache);
3212         update_reserved_extents(root, start, len, 0);
3213
3214         return ret;
3215 }
3216
3217 int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
3218                                   struct btrfs_root *root,
3219                                   u64 num_bytes, u64 min_alloc_size,
3220                                   u64 empty_size, u64 hint_byte,
3221                                   u64 search_end, struct btrfs_key *ins,
3222                                   u64 data)
3223 {
3224         int ret;
3225         ret = __btrfs_reserve_extent(trans, root, num_bytes, min_alloc_size,
3226                                      empty_size, hint_byte, search_end, ins,
3227                                      data);
3228         update_reserved_extents(root, ins->objectid, ins->offset, 1);
3229         return ret;
3230 }
3231
3232 static int __btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
3233                                          struct btrfs_root *root, u64 parent,
3234                                          u64 root_objectid, u64 ref_generation,
3235                                          u64 owner, struct btrfs_key *ins)
3236 {
3237         int ret;
3238         int pending_ret;
3239         u64 super_used;
3240         u64 root_used;
3241         u64 num_bytes = ins->offset;
3242         u32 sizes[2];
3243         struct btrfs_fs_info *info = root->fs_info;
3244         struct btrfs_root *extent_root = info->extent_root;
3245         struct btrfs_extent_item *extent_item;
3246         struct btrfs_extent_ref *ref;
3247         struct btrfs_path *path;
3248         struct btrfs_key keys[2];
3249
3250         if (parent == 0)
3251                 parent = ins->objectid;
3252
3253         /* block accounting for super block */
3254         spin_lock(&info->delalloc_lock);
3255         super_used = btrfs_super_bytes_used(&info->super_copy);
3256         btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
3257
3258         /* block accounting for root item */
3259         root_used = btrfs_root_used(&root->root_item);
3260         btrfs_set_root_used(&root->root_item, root_used + num_bytes);
3261         spin_unlock(&info->delalloc_lock);
3262
3263         if (root == extent_root) {
3264                 struct pending_extent_op *extent_op;
3265
3266                 extent_op = kmalloc(sizeof(*extent_op), GFP_NOFS);
3267                 BUG_ON(!extent_op);
3268
3269                 extent_op->type = PENDING_EXTENT_INSERT;
3270                 extent_op->bytenr = ins->objectid;
3271                 extent_op->num_bytes = ins->offset;
3272                 extent_op->parent = parent;
3273                 extent_op->orig_parent = 0;
3274                 extent_op->generation = ref_generation;
3275                 extent_op->orig_generation = 0;
3276                 extent_op->level = (int)owner;
3277                 INIT_LIST_HEAD(&extent_op->list);
3278                 extent_op->del = 0;
3279
3280                 mutex_lock(&root->fs_info->extent_ins_mutex);
3281                 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
3282                                 ins->objectid + ins->offset - 1,
3283                                 EXTENT_WRITEBACK, GFP_NOFS);
3284                 set_state_private(&root->fs_info->extent_ins,
3285                                   ins->objectid, (unsigned long)extent_op);
3286                 mutex_unlock(&root->fs_info->extent_ins_mutex);
3287                 goto update_block;
3288         }
3289
3290         memcpy(&keys[0], ins, sizeof(*ins));
3291         keys[1].objectid = ins->objectid;
3292         keys[1].type = BTRFS_EXTENT_REF_KEY;
3293         keys[1].offset = parent;
3294         sizes[0] = sizeof(*extent_item);
3295         sizes[1] = sizeof(*ref);
3296
3297         path = btrfs_alloc_path();
3298         BUG_ON(!path);
3299
3300         ret = btrfs_insert_empty_items(trans, extent_root, path, keys,
3301                                        sizes, 2);
3302         BUG_ON(ret);
3303
3304         extent_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
3305                                      struct btrfs_extent_item);
3306         btrfs_set_extent_refs(path->nodes[0], extent_item, 1);
3307         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
3308                              struct btrfs_extent_ref);
3309
3310         btrfs_set_ref_root(path->nodes[0], ref, root_objectid);
3311         btrfs_set_ref_generation(path->nodes[0], ref, ref_generation);
3312         btrfs_set_ref_objectid(path->nodes[0], ref, owner);
3313         btrfs_set_ref_num_refs(path->nodes[0], ref, 1);
3314
3315         btrfs_mark_buffer_dirty(path->nodes[0]);
3316
3317         trans->alloc_exclude_start = 0;
3318         trans->alloc_exclude_nr = 0;
3319         btrfs_free_path(path);
3320         finish_current_insert(trans, extent_root, 0);
3321         pending_ret = del_pending_extents(trans, extent_root, 0);
3322
3323         if (ret)
3324                 goto out;
3325         if (pending_ret) {
3326                 ret = pending_ret;
3327                 goto out;
3328         }
3329
3330 update_block:
3331         ret = update_block_group(trans, root, ins->objectid,
3332                                  ins->offset, 1, 0);
3333         if (ret) {
3334                 printk(KERN_ERR "btrfs update block group failed for %llu "
3335                        "%llu\n", (unsigned long long)ins->objectid,
3336                        (unsigned long long)ins->offset);
3337                 BUG();
3338         }
3339 out:
3340         return ret;
3341 }
3342
3343 int btrfs_alloc_reserved_extent(struct btrfs_trans_handle *trans,
3344                                 struct btrfs_root *root, u64 parent,
3345                                 u64 root_objectid, u64 ref_generation,
3346                                 u64 owner, struct btrfs_key *ins)
3347 {
3348         int ret;
3349
3350         if (root_objectid == BTRFS_TREE_LOG_OBJECTID)
3351                 return 0;
3352         ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
3353                                             ref_generation, owner, ins);
3354         update_reserved_extents(root, ins->objectid, ins->offset, 0);
3355         return ret;
3356 }
3357
3358 /*
3359  * this is used by the tree logging recovery code.  It records that
3360  * an extent has been allocated and makes sure to clear the free
3361  * space cache bits as well
3362  */
3363 int btrfs_alloc_logged_extent(struct btrfs_trans_handle *trans,
3364                                 struct btrfs_root *root, u64 parent,
3365                                 u64 root_objectid, u64 ref_generation,
3366                                 u64 owner, struct btrfs_key *ins)
3367 {
3368         int ret;
3369         struct btrfs_block_group_cache *block_group;
3370
3371         block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid);
3372         mutex_lock(&block_group->cache_mutex);
3373         cache_block_group(root, block_group);
3374         mutex_unlock(&block_group->cache_mutex);
3375
3376         ret = btrfs_remove_free_space(block_group, ins->objectid,
3377                                       ins->offset);
3378         BUG_ON(ret);
3379         put_block_group(block_group);
3380         ret = __btrfs_alloc_reserved_extent(trans, root, parent, root_objectid,
3381                                             ref_generation, owner, ins);
3382         return ret;
3383 }
3384
3385 /*
3386  * finds a free extent and does all the dirty work required for allocation
3387  * returns the key for the extent through ins, and a tree buffer for
3388  * the first block of the extent through buf.
3389  *
3390  * returns 0 if everything worked, non-zero otherwise.
3391  */
3392 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
3393                        struct btrfs_root *root,
3394                        u64 num_bytes, u64 parent, u64 min_alloc_size,
3395                        u64 root_objectid, u64 ref_generation,
3396                        u64 owner_objectid, u64 empty_size, u64 hint_byte,
3397                        u64 search_end, struct btrfs_key *ins, u64 data)
3398 {
3399         int ret;
3400
3401         ret = __btrfs_reserve_extent(trans, root, num_bytes,
3402                                      min_alloc_size, empty_size, hint_byte,
3403                                      search_end, ins, data);
3404         BUG_ON(ret);
3405         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
3406                 ret = __btrfs_alloc_reserved_extent(trans, root, parent,
3407                                         root_objectid, ref_generation,
3408                                         owner_objectid, ins);
3409                 BUG_ON(ret);
3410
3411         } else {
3412                 update_reserved_extents(root, ins->objectid, ins->offset, 1);
3413         }
3414         return ret;
3415 }
3416
3417 struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
3418                                             struct btrfs_root *root,
3419                                             u64 bytenr, u32 blocksize,
3420                                             int level)
3421 {
3422         struct extent_buffer *buf;
3423
3424         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
3425         if (!buf)
3426                 return ERR_PTR(-ENOMEM);
3427         btrfs_set_header_generation(buf, trans->transid);
3428         btrfs_set_buffer_lockdep_class(buf, level);
3429         btrfs_tree_lock(buf);
3430         clean_tree_block(trans, root, buf);
3431
3432         btrfs_set_lock_blocking(buf);
3433         btrfs_set_buffer_uptodate(buf);
3434
3435         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
3436                 set_extent_dirty(&root->dirty_log_pages, buf->start,
3437                          buf->start + buf->len - 1, GFP_NOFS);
3438         } else {
3439                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
3440                          buf->start + buf->len - 1, GFP_NOFS);
3441         }
3442         trans->blocks_used++;
3443         /* this returns a buffer locked for blocking */
3444         return buf;
3445 }
3446
3447 /*
3448  * helper function to allocate a block for a given tree
3449  * returns the tree buffer or NULL.
3450  */
3451 struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
3452                                              struct btrfs_root *root,
3453                                              u32 blocksize, u64 parent,
3454                                              u64 root_objectid,
3455                                              u64 ref_generation,
3456                                              int level,
3457                                              u64 hint,
3458                                              u64 empty_size)
3459 {
3460         struct btrfs_key ins;
3461         int ret;
3462         struct extent_buffer *buf;
3463
3464         ret = btrfs_alloc_extent(trans, root, blocksize, parent, blocksize,
3465                                  root_objectid, ref_generation, level,
3466                                  empty_size, hint, (u64)-1, &ins, 0);
3467         if (ret) {
3468                 BUG_ON(ret > 0);
3469                 return ERR_PTR(ret);
3470         }
3471
3472         buf = btrfs_init_new_buffer(trans, root, ins.objectid,
3473                                     blocksize, level);
3474         return buf;
3475 }
3476
3477 int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
3478                         struct btrfs_root *root, struct extent_buffer *leaf)
3479 {
3480         u64 leaf_owner;
3481         u64 leaf_generation;
3482         struct refsort *sorted;
3483         struct btrfs_key key;
3484         struct btrfs_file_extent_item *fi;
3485         int i;
3486         int nritems;
3487         int ret;
3488         int refi = 0;
3489         int slot;
3490
3491         BUG_ON(!btrfs_is_leaf(leaf));
3492         nritems = btrfs_header_nritems(leaf);
3493         leaf_owner = btrfs_header_owner(leaf);
3494         leaf_generation = btrfs_header_generation(leaf);
3495
3496         sorted = kmalloc(sizeof(*sorted) * nritems, GFP_NOFS);
3497         /* we do this loop twice.  The first time we build a list
3498          * of the extents we have a reference on, then we sort the list
3499          * by bytenr.  The second time around we actually do the
3500          * extent freeing.
3501          */
3502         for (i = 0; i < nritems; i++) {
3503                 u64 disk_bytenr;
3504                 cond_resched();
3505
3506                 btrfs_item_key_to_cpu(leaf, &key, i);
3507
3508                 /* only extents have references, skip everything else */
3509                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3510                         continue;
3511
3512                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
3513
3514                 /* inline extents live in the btree, they don't have refs */
3515                 if (btrfs_file_extent_type(leaf, fi) ==
3516                     BTRFS_FILE_EXTENT_INLINE)
3517                         continue;
3518
3519                 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
3520
3521                 /* holes don't have refs */
3522                 if (disk_bytenr == 0)
3523                         continue;
3524
3525                 sorted[refi].bytenr = disk_bytenr;
3526                 sorted[refi].slot = i;
3527                 refi++;
3528         }
3529
3530         if (refi == 0)
3531                 goto out;
3532
3533         sort(sorted, refi, sizeof(struct refsort), refsort_cmp, NULL);
3534
3535         for (i = 0; i < refi; i++) {
3536                 u64 disk_bytenr;
3537
3538                 disk_bytenr = sorted[i].bytenr;
3539                 slot = sorted[i].slot;
3540
3541                 cond_resched();
3542
3543                 btrfs_item_key_to_cpu(leaf, &key, slot);
3544                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
3545                         continue;
3546
3547                 fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
3548
3549                 ret = __btrfs_free_extent(trans, root, disk_bytenr,
3550                                 btrfs_file_extent_disk_num_bytes(leaf, fi),
3551                                 leaf->start, leaf_owner, leaf_generation,
3552                                 key.objectid, 0);
3553                 BUG_ON(ret);
3554
3555                 atomic_inc(&root->fs_info->throttle_gen);
3556                 wake_up(&root->fs_info->transaction_throttle);
3557                 cond_resched();
3558         }
3559 out:
3560         kfree(sorted);
3561         return 0;
3562 }
3563
3564 static noinline int cache_drop_leaf_ref(struct btrfs_trans_handle *trans,
3565                                         struct btrfs_root *root,
3566                                         struct btrfs_leaf_ref *ref)
3567 {
3568         int i;
3569         int ret;
3570         struct btrfs_extent_info *info;
3571         struct refsort *sorted;
3572
3573         if (ref->nritems == 0)
3574                 return 0;
3575
3576         sorted = kmalloc(sizeof(*sorted) * ref->nritems, GFP_NOFS);
3577         for (i = 0; i < ref->nritems; i++) {
3578                 sorted[i].bytenr = ref->extents[i].bytenr;
3579                 sorted[i].slot = i;
3580         }
3581         sort(sorted, ref->nritems, sizeof(struct refsort), refsort_cmp, NULL);
3582
3583         /*
3584          * the items in the ref were sorted when the ref was inserted
3585          * into the ref cache, so this is already in order
3586          */
3587         for (i = 0; i < ref->nritems; i++) {
3588                 info = ref->extents + sorted[i].slot;
3589                 ret = __btrfs_free_extent(trans, root, info->bytenr,
3590                                           info->num_bytes, ref->bytenr,
3591                                           ref->owner, ref->generation,
3592                                           info->objectid, 0);
3593
3594                 atomic_inc(&root->fs_info->throttle_gen);
3595                 wake_up(&root->fs_info->transaction_throttle);
3596                 cond_resched();
3597
3598                 BUG_ON(ret);
3599                 info++;
3600         }
3601
3602         kfree(sorted);
3603         return 0;
3604 }
3605
3606 static int drop_snap_lookup_refcount(struct btrfs_root *root, u64 start,
3607                                      u64 len, u32 *refs)
3608 {
3609         int ret;
3610
3611         ret = btrfs_lookup_extent_ref(NULL, root, start, len, refs);
3612         BUG_ON(ret);
3613
3614 #if 0 /* some debugging code in case we see problems here */
3615         /* if the refs count is one, it won't get increased again.  But
3616          * if the ref count is > 1, someone may be decreasing it at
3617          * the same time we are.
3618          */
3619         if (*refs != 1) {
3620                 struct extent_buffer *eb = NULL;
3621                 eb = btrfs_find_create_tree_block(root, start, len);
3622                 if (eb)
3623                         btrfs_tree_lock(eb);
3624
3625                 mutex_lock(&root->fs_info->alloc_mutex);
3626                 ret = lookup_extent_ref(NULL, root, start, len, refs);
3627                 BUG_ON(ret);
3628                 mutex_unlock(&root->fs_info->alloc_mutex);
3629
3630                 if (eb) {
3631                         btrfs_tree_unlock(eb);
3632                         free_extent_buffer(eb);
3633                 }
3634                 if (*refs == 1) {
3635                         printk(KERN_ERR "btrfs block %llu went down to one "
3636                                "during drop_snap\n", (unsigned long long)start);
3637                 }
3638
3639         }
3640 #endif
3641
3642         cond_resched();
3643         return ret;
3644 }
3645
3646 /*
3647  * this is used while deleting old snapshots, and it drops the refs
3648  * on a whole subtree starting from a level 1 node.
3649  *
3650  * The idea is to sort all the leaf pointers, and then drop the
3651  * ref on all the leaves in order.  Most of the time the leaves
3652  * will have ref cache entries, so no leaf IOs will be required to
3653  * find the extents they have references on.
3654  *
3655  * For each leaf, any references it has are also dropped in order
3656  *
3657  * This ends up dropping the references in something close to optimal
3658  * order for reading and modifying the extent allocation tree.
3659  */
3660 static noinline int drop_level_one_refs(struct btrfs_trans_handle *trans,
3661                                         struct btrfs_root *root,
3662                                         struct btrfs_path *path)
3663 {
3664         u64 bytenr;
3665         u64 root_owner;
3666         u64 root_gen;
3667         struct extent_buffer *eb = path->nodes[1];
3668         struct extent_buffer *leaf;
3669         struct btrfs_leaf_ref *ref;
3670         struct refsort *sorted = NULL;
3671         int nritems = btrfs_header_nritems(eb);
3672         int ret;
3673         int i;
3674         int refi = 0;
3675         int slot = path->slots[1];
3676         u32 blocksize = btrfs_level_size(root, 0);
3677         u32 refs;
3678
3679         if (nritems == 0)
3680                 goto out;
3681
3682         root_owner = btrfs_header_owner(eb);
3683         root_gen = btrfs_header_generation(eb);
3684         sorted = kmalloc(sizeof(*sorted) * nritems, GFP_NOFS);
3685
3686         /*
3687          * step one, sort all the leaf pointers so we don't scribble
3688          * randomly into the extent allocation tree
3689          */
3690         for (i = slot; i < nritems; i++) {
3691                 sorted[refi].bytenr = btrfs_node_blockptr(eb, i);
3692                 sorted[refi].slot = i;
3693                 refi++;
3694         }
3695
3696         /*
3697          * nritems won't be zero, but if we're picking up drop_snapshot
3698          * after a crash, slot might be > 0, so double check things
3699          * just in case.
3700          */
3701         if (refi == 0)
3702                 goto out;
3703
3704         sort(sorted, refi, sizeof(struct refsort), refsort_cmp, NULL);
3705
3706         /*
3707          * the first loop frees everything the leaves point to
3708          */
3709         for (i = 0; i < refi; i++) {
3710                 u64 ptr_gen;
3711
3712                 bytenr = sorted[i].bytenr;
3713
3714                 /*
3715                  * check the reference count on this leaf.  If it is > 1
3716                  * we just decrement it below and don't update any
3717                  * of the refs the leaf points to.
3718                  */
3719                 ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
3720                 BUG_ON(ret);
3721                 if (refs != 1)
3722                         continue;
3723
3724                 ptr_gen = btrfs_node_ptr_generation(eb, sorted[i].slot);
3725
3726                 /*
3727                  * the leaf only had one reference, which means the
3728                  * only thing pointing to this leaf is the snapshot
3729                  * we're deleting.  It isn't possible for the reference
3730                  * count to increase again later
3731                  *
3732                  * The reference cache is checked for the leaf,
3733                  * and if found we'll be able to drop any refs held by
3734                  * the leaf without needing to read it in.
3735                  */
3736                 ref = btrfs_lookup_leaf_ref(root, bytenr);
3737                 if (ref && ref->generation != ptr_gen) {
3738                         btrfs_free_leaf_ref(root, ref);
3739                         ref = NULL;
3740                 }
3741                 if (ref) {
3742                         ret = cache_drop_leaf_ref(trans, root, ref);
3743                         BUG_ON(ret);
3744                         btrfs_remove_leaf_ref(root, ref);
3745                         btrfs_free_leaf_ref(root, ref);
3746                 } else {
3747                         /*
3748                          * the leaf wasn't in the reference cache, so
3749                          * we have to read it.
3750                          */
3751                         leaf = read_tree_block(root, bytenr, blocksize,
3752                                                ptr_gen);
3753                         ret = btrfs_drop_leaf_ref(trans, root, leaf);
3754                         BUG_ON(ret);
3755                         free_extent_buffer(leaf);
3756                 }
3757                 atomic_inc(&root->fs_info->throttle_gen);
3758                 wake_up(&root->fs_info->transaction_throttle);
3759                 cond_resched();
3760         }
3761
3762         /*
3763          * run through the loop again to free the refs on the leaves.
3764          * This is faster than doing it in the loop above because
3765          * the leaves are likely to be clustered together.  We end up
3766          * working in nice chunks on the extent allocation tree.
3767          */
3768         for (i = 0; i < refi; i++) {
3769                 bytenr = sorted[i].bytenr;
3770                 ret = __btrfs_free_extent(trans, root, bytenr,
3771                                         blocksize, eb->start,
3772                                         root_owner, root_gen, 0, 1);
3773                 BUG_ON(ret);
3774
3775                 atomic_inc(&root->fs_info->throttle_gen);
3776                 wake_up(&root->fs_info->transaction_throttle);
3777                 cond_resched();
3778         }
3779 out:
3780         kfree(sorted);
3781
3782         /*
3783          * update the path to show we've processed the entire level 1
3784          * node.  This will get saved into the root's drop_snapshot_progress
3785          * field so these drops are not repeated again if this transaction
3786          * commits.
3787          */
3788         path->slots[1] = nritems;
3789         return 0;
3790 }
3791
3792 /*
3793  * helper function for drop_snapshot, this walks down the tree dropping ref
3794  * counts as it goes.
3795  */
3796 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
3797                                    struct btrfs_root *root,
3798                                    struct btrfs_path *path, int *level)
3799 {
3800         u64 root_owner;
3801         u64 root_gen;
3802         u64 bytenr;
3803         u64 ptr_gen;
3804         struct extent_buffer *next;
3805         struct extent_buffer *cur;
3806         struct extent_buffer *parent;
3807         u32 blocksize;
3808         int ret;
3809         u32 refs;
3810
3811         WARN_ON(*level < 0);
3812         WARN_ON(*level >= BTRFS_MAX_LEVEL);
3813         ret = drop_snap_lookup_refcount(root, path->nodes[*level]->start,
3814                                 path->nodes[*level]->len, &refs);
3815         BUG_ON(ret);
3816         if (refs > 1)
3817                 goto out;
3818
3819         /*
3820          * walk down to the last node level and free all the leaves
3821          */
3822         while (*level >= 0) {
3823                 WARN_ON(*level < 0);
3824                 WARN_ON(*level >= BTRFS_MAX_LEVEL);
3825                 cur = path->nodes[*level];
3826
3827                 if (btrfs_header_level(cur) != *level)
3828                         WARN_ON(1);
3829
3830                 if (path->slots[*level] >=
3831                     btrfs_header_nritems(cur))
3832                         break;
3833
3834                 /* the new code goes down to level 1 and does all the
3835                  * leaves pointed to that node in bulk.  So, this check
3836                  * for level 0 will always be false.
3837                  *
3838                  * But, the disk format allows the drop_snapshot_progress
3839                  * field in the root to leave things in a state where
3840                  * a leaf will need cleaning up here.  If someone crashes
3841                  * with the old code and then boots with the new code,
3842                  * we might find a leaf here.
3843                  */
3844                 if (*level == 0) {
3845                         ret = btrfs_drop_leaf_ref(trans, root, cur);
3846                         BUG_ON(ret);
3847                         break;
3848                 }
3849
3850                 /*
3851                  * once we get to level one, process the whole node
3852                  * at once, including everything below it.
3853                  */
3854                 if (*level == 1) {
3855                         ret = drop_level_one_refs(trans, root, path);
3856                         BUG_ON(ret);
3857                         break;
3858                 }
3859
3860                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
3861                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
3862                 blocksize = btrfs_level_size(root, *level - 1);
3863
3864                 ret = drop_snap_lookup_refcount(root, bytenr, blocksize, &refs);
3865                 BUG_ON(ret);
3866
3867                 /*
3868                  * if there is more than one reference, we don't need
3869                  * to read that node to drop any references it has.  We
3870                  * just drop the ref we hold on that node and move on to the
3871                  * next slot in this level.
3872                  */
3873                 if (refs != 1) {
3874                         parent = path->nodes[*level];
3875                         root_owner = btrfs_header_owner(parent);
3876                         root_gen = btrfs_header_generation(parent);
3877                         path->slots[*level]++;
3878
3879                         ret = __btrfs_free_extent(trans, root, bytenr,
3880                                                 blocksize, parent->start,
3881                                                 root_owner, root_gen,
3882                                                 *level - 1, 1);
3883                         BUG_ON(ret);
3884
3885                         atomic_inc(&root->fs_info->throttle_gen);
3886                         wake_up(&root->fs_info->transaction_throttle);
3887                         cond_resched();
3888
3889                         continue;
3890                 }
3891
3892                 /*
3893                  * we need to keep freeing things in the next level down.
3894                  * read the block and loop around to process it
3895                  */
3896                 next = read_tree_block(root, bytenr, blocksize, ptr_gen);
3897                 WARN_ON(*level <= 0);
3898                 if (path->nodes[*level-1])
3899                         free_extent_buffer(path->nodes[*level-1]);
3900                 path->nodes[*level-1] = next;
3901                 *level = btrfs_header_level(next);
3902                 path->slots[*level] = 0;
3903                 cond_resched();
3904         }
3905 out:
3906         WARN_ON(*level < 0);
3907         WARN_ON(*level >= BTRFS_MAX_LEVEL);
3908
3909         if (path->nodes[*level] == root->node) {
3910                 parent = path->nodes[*level];
3911                 bytenr = path->nodes[*level]->start;
3912         } else {
3913                 parent = path->nodes[*level + 1];
3914                 bytenr = btrfs_node_blockptr(parent, path->slots[*level + 1]);
3915         }
3916
3917         blocksize = btrfs_level_size(root, *level);
3918         root_owner = btrfs_header_owner(parent);
3919         root_gen = btrfs_header_generation(parent);
3920
3921         /*
3922          * cleanup and free the reference on the last node
3923          * we processed
3924          */
3925         ret = __btrfs_free_extent(trans, root, bytenr, blocksize,
3926                                   parent->start, root_owner, root_gen,
3927                                   *level, 1);
3928         free_extent_buffer(path->nodes[*level]);
3929         path->nodes[*level] = NULL;
3930
3931         *level += 1;
3932         BUG_ON(ret);
3933
3934         cond_resched();
3935         return 0;
3936 }
3937
3938 /*
3939  * helper function for drop_subtree, this function is similar to
3940  * walk_down_tree. The main difference is that it checks reference
3941  * counts while tree blocks are locked.
3942  */
3943 static noinline int walk_down_subtree(struct btrfs_trans_handle *trans,
3944                                       struct btrfs_root *root,
3945                                       struct btrfs_path *path, int *level)
3946 {
3947         struct extent_buffer *next;
3948         struct extent_buffer *cur;
3949         struct extent_buffer *parent;
3950         u64 bytenr;
3951         u64 ptr_gen;
3952         u32 blocksize;
3953         u32 refs;
3954         int ret;
3955
3956         cur = path->nodes[*level];
3957         ret = btrfs_lookup_extent_ref(trans, root, cur->start, cur->len,
3958                                       &refs);
3959         BUG_ON(ret);
3960         if (refs > 1)
3961                 goto out;
3962
3963         while (*level >= 0) {
3964                 cur = path->nodes[*level];
3965                 if (*level == 0) {
3966                         ret = btrfs_drop_leaf_ref(trans, root, cur);
3967                         BUG_ON(ret);
3968                         clean_tree_block(trans, root, cur);
3969                         break;
3970                 }
3971                 if (path->slots[*level] >= btrfs_header_nritems(cur)) {
3972                         clean_tree_block(trans, root, cur);
3973                         break;
3974                 }
3975
3976                 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
3977                 blocksize = btrfs_level_size(root, *level - 1);
3978                 ptr_gen = btrfs_node_ptr_generation(cur, path->slots[*level]);
3979
3980                 next = read_tree_block(root, bytenr, blocksize, ptr_gen);
3981                 btrfs_tree_lock(next);
3982                 btrfs_set_lock_blocking(next);
3983
3984                 ret = btrfs_lookup_extent_ref(trans, root, bytenr, blocksize,
3985                                               &refs);
3986                 BUG_ON(ret);
3987                 if (refs > 1) {
3988                         parent = path->nodes[*level];
3989                         ret = btrfs_free_extent(trans, root, bytenr,
3990                                         blocksize, parent->start,
3991                                         btrfs_header_owner(parent),
3992                                         btrfs_header_generation(parent),
3993                                         *level - 1, 1);
3994                         BUG_ON(ret);
3995                         path->slots[*level]++;
3996                         btrfs_tree_unlock(next);
3997                         free_extent_buffer(next);
3998                         continue;
3999                 }
4000
4001                 *level = btrfs_header_level(next);
4002                 path->nodes[*level] = next;
4003                 path->slots[*level] = 0;
4004                 path->locks[*level] = 1;
4005                 cond_resched();
4006         }
4007 out:
4008         parent = path->nodes[*level + 1];
4009         bytenr = path->nodes[*level]->start;
4010         blocksize = path->nodes[*level]->len;
4011
4012         ret = btrfs_free_extent(trans, root, bytenr, blocksize,
4013                         parent->start, btrfs_header_owner(parent),
4014                         btrfs_header_generation(parent), *level, 1);
4015         BUG_ON(ret);
4016
4017         if (path->locks[*level]) {
4018                 btrfs_tree_unlock(path->nodes[*level]);
4019                 path->locks[*level] = 0;
4020         }
4021         free_extent_buffer(path->nodes[*level]);
4022         path->nodes[*level] = NULL;
4023         *level += 1;
4024         cond_resched();
4025         return 0;
4026 }
4027
4028 /*
4029  * helper for dropping snapshots.  This walks back up the tree in the path
4030  * to find the first node higher up where we haven't yet gone through
4031  * all the slots
4032  */
4033 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
4034                                  struct btrfs_root *root,
4035                                  struct btrfs_path *path,
4036                                  int *level, int max_level)
4037 {
4038         u64 root_owner;
4039         u64 root_gen;
4040         struct btrfs_root_item *root_item = &root->root_item;
4041         int i;
4042         int slot;
4043         int ret;
4044
4045         for (i = *level; i < max_level && path->nodes[i]; i++) {
4046                 slot = path->slots[i];
4047                 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
4048                         struct extent_buffer *node;
4049                         struct btrfs_disk_key disk_key;
4050
4051                         /*
4052                          * there is more work to do in this level.
4053                          * Update the drop_progress marker to reflect
4054                          * the work we've done so far, and then bump
4055                          * the slot number
4056                          */
4057                         node = path->nodes[i];
4058                         path->slots[i]++;
4059                         *level = i;
4060                         WARN_ON(*level == 0);
4061                         btrfs_node_key(node, &disk_key, path->slots[i]);
4062                         memcpy(&root_item->drop_progress,
4063                                &disk_key, sizeof(disk_key));
4064                         root_item->drop_level = i;
4065                         return 0;
4066                 } else {
4067                         struct extent_buffer *parent;
4068
4069                         /*
4070                          * this whole node is done, free our reference
4071                          * on it and go up one level
4072                          */
4073                         if (path->nodes[*level] == root->node)
4074                                 parent = path->nodes[*level];
4075                         else
4076                                 parent = path->nodes[*level + 1];
4077
4078                         root_owner = btrfs_header_owner(parent);
4079                         root_gen = btrfs_header_generation(parent);
4080
4081                         clean_tree_block(trans, root, path->nodes[*level]);
4082                         ret = btrfs_free_extent(trans, root,
4083                                                 path->nodes[*level]->start,
4084                                                 path->nodes[*level]->len,
4085                                                 parent->start, root_owner,
4086                                                 root_gen, *level, 1);
4087                         BUG_ON(ret);
4088                         if (path->locks[*level]) {
4089                                 btrfs_tree_unlock(path->nodes[*level]);
4090                                 path->locks[*level] = 0;
4091                         }
4092                         free_extent_buffer(path->nodes[*level]);
4093                         path->nodes[*level] = NULL;
4094                         *level = i + 1;
4095                 }
4096         }
4097         return 1;
4098 }
4099
4100 /*
4101  * drop the reference count on the tree rooted at 'snap'.  This traverses
4102  * the tree freeing any blocks that have a ref count of zero after being
4103  * decremented.
4104  */
4105 int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
4106                         *root)
4107 {
4108         int ret = 0;
4109         int wret;
4110         int level;
4111         struct btrfs_path *path;
4112         int i;
4113         int orig_level;
4114         struct btrfs_root_item *root_item = &root->root_item;
4115
4116         WARN_ON(!mutex_is_locked(&root->fs_info->drop_mutex));
4117         path = btrfs_alloc_path();
4118         BUG_ON(!path);
4119
4120         level = btrfs_header_level(root->node);
4121         orig_level = level;
4122         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
4123                 path->nodes[level] = root->node;
4124                 extent_buffer_get(root->node);
4125                 path->slots[level] = 0;
4126         } else {
4127                 struct btrfs_key key;
4128                 struct btrfs_disk_key found_key;
4129                 struct extent_buffer *node;
4130
4131                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
4132                 level = root_item->drop_level;
4133                 path->lowest_level = level;
4134                 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4135                 if (wret < 0) {
4136                         ret = wret;
4137                         goto out;
4138                 }
4139                 node = path->nodes[level];
4140                 btrfs_node_key(node, &found_key, path->slots[level]);
4141                 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
4142                                sizeof(found_key)));
4143                 /*
4144                  * unlock our path, this is safe because only this
4145                  * function is allowed to delete this snapshot
4146                  */
4147                 for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
4148                         if (path->nodes[i] && path->locks[i]) {
4149                                 path->locks[i] = 0;
4150                                 btrfs_tree_unlock(path->nodes[i]);
4151                         }
4152                 }
4153         }
4154         while (1) {
4155                 wret = walk_down_tree(trans, root, path, &level);
4156                 if (wret > 0)
4157                         break;
4158                 if (wret < 0)
4159                         ret = wret;
4160
4161                 wret = walk_up_tree(trans, root, path, &level,
4162                                     BTRFS_MAX_LEVEL);
4163                 if (wret > 0)
4164                         break;
4165                 if (wret < 0)
4166                         ret = wret;
4167                 if (trans->transaction->in_commit) {
4168                         ret = -EAGAIN;
4169                         break;
4170                 }
4171                 atomic_inc(&root->fs_info->throttle_gen);
4172                 wake_up(&root->fs_info->transaction_throttle);
4173         }
4174         for (i = 0; i <= orig_level; i++) {
4175                 if (path->nodes[i]) {
4176                         free_extent_buffer(path->nodes[i]);
4177                         path->nodes[i] = NULL;
4178                 }
4179         }
4180 out:
4181         btrfs_free_path(path);
4182         return ret;
4183 }
4184
4185 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
4186                         struct btrfs_root *root,
4187                         struct extent_buffer *node,
4188                         struct extent_buffer *parent)
4189 {
4190         struct btrfs_path *path;
4191         int level;
4192         int parent_level;
4193         int ret = 0;
4194         int wret;
4195
4196         path = btrfs_alloc_path();
4197         BUG_ON(!path);
4198
4199         BUG_ON(!btrfs_tree_locked(parent));
4200         parent_level = btrfs_header_level(parent);
4201         extent_buffer_get(parent);
4202         path->nodes[parent_level] = parent;
4203         path->slots[parent_level] = btrfs_header_nritems(parent);
4204
4205         BUG_ON(!btrfs_tree_locked(node));
4206         level = btrfs_header_level(node);
4207         extent_buffer_get(node);
4208         path->nodes[level] = node;
4209         path->slots[level] = 0;
4210
4211         while (1) {
4212                 wret = walk_down_subtree(trans, root, path, &level);
4213                 if (wret < 0)
4214                         ret = wret;
4215                 if (wret != 0)
4216                         break;
4217
4218                 wret = walk_up_tree(trans, root, path, &level, parent_level);
4219                 if (wret < 0)
4220                         ret = wret;
4221                 if (wret != 0)
4222                         break;
4223         }
4224
4225         btrfs_free_path(path);
4226         return ret;
4227 }
4228
4229 static unsigned long calc_ra(unsigned long start, unsigned long last,
4230                              unsigned long nr)
4231 {
4232         return min(last, start + nr - 1);
4233 }
4234
4235 static noinline int relocate_inode_pages(struct inode *inode, u64 start,
4236                                          u64 len)
4237 {
4238         u64 page_start;
4239         u64 page_end;
4240         unsigned long first_index;
4241         unsigned long last_index;
4242         unsigned long i;
4243         struct page *page;
4244         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4245         struct file_ra_state *ra;
4246         struct btrfs_ordered_extent *ordered;
4247         unsigned int total_read = 0;
4248         unsigned int total_dirty = 0;
4249         int ret = 0;
4250
4251         ra = kzalloc(sizeof(*ra), GFP_NOFS);
4252
4253         mutex_lock(&inode->i_mutex);
4254         first_index = start >> PAGE_CACHE_SHIFT;
4255         last_index = (start + len - 1) >> PAGE_CACHE_SHIFT;
4256
4257         /* make sure the dirty trick played by the caller work */
4258         ret = invalidate_inode_pages2_range(inode->i_mapping,
4259                                             first_index, last_index);
4260         if (ret)
4261                 goto out_unlock;
4262
4263         file_ra_state_init(ra, inode->i_mapping);
4264
4265         for (i = first_index ; i <= last_index; i++) {
4266                 if (total_read % ra->ra_pages == 0) {
4267                         btrfs_force_ra(inode->i_mapping, ra, NULL, i,
4268                                        calc_ra(i, last_index, ra->ra_pages));
4269                 }
4270                 total_read++;
4271 again:
4272                 if (((u64)i << PAGE_CACHE_SHIFT) > i_size_read(inode))
4273                         BUG_ON(1);
4274                 page = grab_cache_page(inode->i_mapping, i);
4275                 if (!page) {
4276                         ret = -ENOMEM;
4277                         goto out_unlock;
4278                 }
4279                 if (!PageUptodate(page)) {
4280                         btrfs_readpage(NULL, page);
4281                         lock_page(page);
4282                         if (!PageUptodate(page)) {
4283                                 unlock_page(page);
4284                                 page_cache_release(page);
4285                                 ret = -EIO;
4286                                 goto out_unlock;
4287                         }
4288                 }
4289                 wait_on_page_writeback(page);
4290
4291                 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
4292                 page_end = page_start + PAGE_CACHE_SIZE - 1;
4293                 lock_extent(io_tree, page_start, page_end, GFP_NOFS);
4294
4295                 ordered = btrfs_lookup_ordered_extent(inode, page_start);
4296                 if (ordered) {
4297                         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
4298                         unlock_page(page);
4299                         page_cache_release(page);
4300                         btrfs_start_ordered_extent(inode, ordered, 1);
4301                         btrfs_put_ordered_extent(ordered);
4302                         goto again;
4303                 }
4304                 set_page_extent_mapped(page);
4305
4306                 if (i == first_index)
4307                         set_extent_bits(io_tree, page_start, page_end,
4308                                         EXTENT_BOUNDARY, GFP_NOFS);
4309                 btrfs_set_extent_delalloc(inode, page_start, page_end);
4310
4311                 set_page_dirty(page);
4312                 total_dirty++;
4313
4314                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
4315                 unlock_page(page);
4316                 page_cache_release(page);
4317         }
4318
4319 out_unlock:
4320         kfree(ra);
4321         mutex_unlock(&inode->i_mutex);
4322         balance_dirty_pages_ratelimited_nr(inode->i_mapping, total_dirty);
4323         return ret;
4324 }
4325
4326 static noinline int relocate_data_extent(struct inode *reloc_inode,
4327                                          struct btrfs_key *extent_key,
4328                                          u64 offset)
4329 {
4330         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
4331         struct extent_map_tree *em_tree = &BTRFS_I(reloc_inode)->extent_tree;
4332         struct extent_map *em;
4333         u64 start = extent_key->objectid - offset;
4334         u64 end = start + extent_key->offset - 1;
4335
4336         em = alloc_extent_map(GFP_NOFS);
4337         BUG_ON(!em || IS_ERR(em));
4338
4339         em->start = start;
4340         em->len = extent_key->offset;
4341         em->block_len = extent_key->offset;
4342         em->block_start = extent_key->objectid;
4343         em->bdev = root->fs_info->fs_devices->latest_bdev;
4344         set_bit(EXTENT_FLAG_PINNED, &em->flags);
4345
4346         /* setup extent map to cheat btrfs_readpage */
4347         lock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
4348         while (1) {
4349                 int ret;
4350                 spin_lock(&em_tree->lock);
4351                 ret = add_extent_mapping(em_tree, em);
4352                 spin_unlock(&em_tree->lock);
4353                 if (ret != -EEXIST) {
4354                         free_extent_map(em);
4355                         break;
4356                 }
4357                 btrfs_drop_extent_cache(reloc_inode, start, end, 0);
4358         }
4359         unlock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
4360
4361         return relocate_inode_pages(reloc_inode, start, extent_key->offset);
4362 }
4363
4364 struct btrfs_ref_path {
4365         u64 extent_start;
4366         u64 nodes[BTRFS_MAX_LEVEL];
4367         u64 root_objectid;
4368         u64 root_generation;
4369         u64 owner_objectid;
4370         u32 num_refs;
4371         int lowest_level;
4372         int current_level;
4373         int shared_level;
4374
4375         struct btrfs_key node_keys[BTRFS_MAX_LEVEL];
4376         u64 new_nodes[BTRFS_MAX_LEVEL];
4377 };
4378
4379 struct disk_extent {
4380         u64 ram_bytes;
4381         u64 disk_bytenr;
4382         u64 disk_num_bytes;
4383         u64 offset;
4384         u64 num_bytes;
4385         u8 compression;
4386         u8 encryption;
4387         u16 other_encoding;
4388 };
4389
4390 static int is_cowonly_root(u64 root_objectid)
4391 {
4392         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
4393             root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
4394             root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
4395             root_objectid == BTRFS_DEV_TREE_OBJECTID ||
4396             root_objectid == BTRFS_TREE_LOG_OBJECTID ||
4397             root_objectid == BTRFS_CSUM_TREE_OBJECTID)
4398                 return 1;
4399         return 0;
4400 }
4401
4402 static noinline int __next_ref_path(struct btrfs_trans_handle *trans,
4403                                     struct btrfs_root *extent_root,
4404                                     struct btrfs_ref_path *ref_path,
4405                                     int first_time)
4406 {
4407         struct extent_buffer *leaf;
4408         struct btrfs_path *path;
4409         struct btrfs_extent_ref *ref;
4410         struct btrfs_key key;
4411         struct btrfs_key found_key;
4412         u64 bytenr;
4413         u32 nritems;
4414         int level;
4415         int ret = 1;
4416
4417         path = btrfs_alloc_path();
4418         if (!path)
4419                 return -ENOMEM;
4420
4421         if (first_time) {
4422                 ref_path->lowest_level = -1;
4423                 ref_path->current_level = -1;
4424                 ref_path->shared_level = -1;
4425                 goto walk_up;
4426         }
4427 walk_down:
4428         level = ref_path->current_level - 1;
4429         while (level >= -1) {
4430                 u64 parent;
4431                 if (level < ref_path->lowest_level)
4432                         break;
4433
4434                 if (level >= 0)
4435                         bytenr = ref_path->nodes[level];
4436                 else
4437                         bytenr = ref_path->extent_start;
4438                 BUG_ON(bytenr == 0);
4439
4440                 parent = ref_path->nodes[level + 1];
4441                 ref_path->nodes[level + 1] = 0;
4442                 ref_path->current_level = level;
4443                 BUG_ON(parent == 0);
4444
4445                 key.objectid = bytenr;
4446                 key.offset = parent + 1;
4447                 key.type = BTRFS_EXTENT_REF_KEY;
4448
4449                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
4450                 if (ret < 0)
4451                         goto out;
4452                 BUG_ON(ret == 0);
4453
4454                 leaf = path->nodes[0];
4455                 nritems = btrfs_header_nritems(leaf);
4456                 if (path->slots[0] >= nritems) {
4457                         ret = btrfs_next_leaf(extent_root, path);
4458                         if (ret < 0)
4459                                 goto out;
4460                         if (ret > 0)
4461                                 goto next;
4462                         leaf = path->nodes[0];
4463                 }
4464
4465                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4466                 if (found_key.objectid == bytenr &&
4467                     found_key.type == BTRFS_EXTENT_REF_KEY) {
4468                         if (level < ref_path->shared_level)
4469                                 ref_path->shared_level = level;
4470                         goto found;
4471                 }
4472 next:
4473                 level--;
4474                 btrfs_release_path(extent_root, path);
4475                 cond_resched();
4476         }
4477         /* reached lowest level */
4478         ret = 1;
4479         goto out;
4480 walk_up:
4481         level = ref_path->current_level;
4482         while (level < BTRFS_MAX_LEVEL - 1) {
4483                 u64 ref_objectid;
4484
4485                 if (level >= 0)
4486                         bytenr = ref_path->nodes[level];
4487                 else
4488                         bytenr = ref_path->extent_start;
4489
4490                 BUG_ON(bytenr == 0);
4491
4492                 key.objectid = bytenr;
4493                 key.offset = 0;
4494                 key.type = BTRFS_EXTENT_REF_KEY;
4495
4496                 ret = btrfs_search_slot(trans, extent_root, &key, path, 0, 0);
4497                 if (ret < 0)
4498                         goto out;
4499
4500                 leaf = path->nodes[0];
4501                 nritems = btrfs_header_nritems(leaf);
4502                 if (path->slots[0] >= nritems) {
4503                         ret = btrfs_next_leaf(extent_root, path);
4504                         if (ret < 0)
4505                                 goto out;
4506                         if (ret > 0) {
4507                                 /* the extent was freed by someone */
4508                                 if (ref_path->lowest_level == level)
4509                                         goto out;
4510                                 btrfs_release_path(extent_root, path);
4511                                 goto walk_down;
4512                         }
4513                         leaf = path->nodes[0];
4514                 }
4515
4516                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4517                 if (found_key.objectid != bytenr ||
4518                                 found_key.type != BTRFS_EXTENT_REF_KEY) {
4519                         /* the extent was freed by someone */
4520                         if (ref_path->lowest_level == level) {
4521                                 ret = 1;
4522                                 goto out;
4523                         }
4524                         btrfs_release_path(extent_root, path);
4525                         goto walk_down;
4526                 }
4527 found:
4528                 ref = btrfs_item_ptr(leaf, path->slots[0],
4529                                 struct btrfs_extent_ref);
4530                 ref_objectid = btrfs_ref_objectid(leaf, ref);
4531                 if (ref_objectid < BTRFS_FIRST_FREE_OBJECTID) {
4532                         if (first_time) {
4533                                 level = (int)ref_objectid;
4534                                 BUG_ON(level >= BTRFS_MAX_LEVEL);
4535                                 ref_path->lowest_level = level;
4536                                 ref_path->current_level = level;
4537                                 ref_path->nodes[level] = bytenr;
4538                         } else {
4539                                 WARN_ON(ref_objectid != level);
4540                         }
4541                 } else {
4542                         WARN_ON(level != -1);
4543                 }
4544                 first_time = 0;
4545
4546                 if (ref_path->lowest_level == level) {
4547                         ref_path->owner_objectid = ref_objectid;
4548                         ref_path->num_refs = btrfs_ref_num_refs(leaf, ref);
4549                 }
4550
4551                 /*
4552                  * the block is tree root or the block isn't in reference
4553                  * counted tree.
4554                  */
4555                 if (found_key.objectid == found_key.offset ||
4556                     is_cowonly_root(btrfs_ref_root(leaf, ref))) {
4557                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
4558                         ref_path->root_generation =
4559                                 btrfs_ref_generation(leaf, ref);
4560                         if (level < 0) {
4561                                 /* special reference from the tree log */
4562                                 ref_path->nodes[0] = found_key.offset;
4563                                 ref_path->current_level = 0;
4564                         }
4565                         ret = 0;
4566                         goto out;
4567                 }
4568
4569                 level++;
4570                 BUG_ON(ref_path->nodes[level] != 0);
4571                 ref_path->nodes[level] = found_key.offset;
4572                 ref_path->current_level = level;
4573
4574                 /*
4575                  * the reference was created in the running transaction,
4576                  * no need to continue walking up.
4577                  */
4578                 if (btrfs_ref_generation(leaf, ref) == trans->transid) {
4579                         ref_path->root_objectid = btrfs_ref_root(leaf, ref);
4580                         ref_path->root_generation =
4581                                 btrfs_ref_generation(leaf, ref);
4582                         ret = 0;
4583                         goto out;
4584                 }
4585
4586                 btrfs_release_path(extent_root, path);
4587                 cond_resched();
4588         }
4589         /* reached max tree level, but no tree root found. */
4590         BUG();
4591 out:
4592         btrfs_free_path(path);
4593         return ret;
4594 }
4595
4596 static int btrfs_first_ref_path(struct btrfs_trans_handle *trans,
4597                                 struct btrfs_root *extent_root,
4598                                 struct btrfs_ref_path *ref_path,
4599                                 u64 extent_start)
4600 {
4601         memset(ref_path, 0, sizeof(*ref_path));
4602         ref_path->extent_start = extent_start;
4603
4604         return __next_ref_path(trans, extent_root, ref_path, 1);
4605 }
4606
4607 static int btrfs_next_ref_path(struct btrfs_trans_handle *trans,
4608                                struct btrfs_root *extent_root,
4609                                struct btrfs_ref_path *ref_path)
4610 {
4611         return __next_ref_path(trans, extent_root, ref_path, 0);
4612 }
4613
4614 static noinline int get_new_locations(struct inode *reloc_inode,
4615                                       struct btrfs_key *extent_key,
4616                                       u64 offset, int no_fragment,
4617                                       struct disk_extent **extents,
4618                                       int *nr_extents)
4619 {
4620         struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
4621         struct btrfs_path *path;
4622         struct btrfs_file_extent_item *fi;
4623         struct extent_buffer *leaf;
4624         struct disk_extent *exts = *extents;
4625         struct btrfs_key found_key;
4626         u64 cur_pos;
4627         u64 last_byte;
4628         u32 nritems;
4629         int nr = 0;
4630         int max = *nr_extents;
4631         int ret;
4632
4633         WARN_ON(!no_fragment && *extents);
4634         if (!exts) {
4635                 max = 1;
4636                 exts = kmalloc(sizeof(*exts) * max, GFP_NOFS);
4637                 if (!exts)
4638                         return -ENOMEM;
4639         }
4640
4641         path = btrfs_alloc_path();
4642         BUG_ON(!path);
4643
4644         cur_pos = extent_key->objectid - offset;
4645         last_byte = extent_key->objectid + extent_key->offset;
4646         ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
4647                                        cur_pos, 0);
4648         if (ret < 0)
4649                 goto out;
4650         if (ret > 0) {
4651                 ret = -ENOENT;
4652                 goto out;
4653         }
4654
4655         while (1) {
4656                 leaf = path->nodes[0];
4657                 nritems = btrfs_header_nritems(leaf);
4658                 if (path->slots[0] >= nritems) {
4659                         ret = btrfs_next_leaf(root, path);
4660                         if (ret < 0)
4661                                 goto out;
4662                         if (ret > 0)
4663                                 break;
4664                         leaf = path->nodes[0];
4665                 }
4666
4667                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4668                 if (found_key.offset != cur_pos ||
4669                     found_key.type != BTRFS_EXTENT_DATA_KEY ||
4670                     found_key.objectid != reloc_inode->i_ino)
4671                         break;
4672
4673                 fi = btrfs_item_ptr(leaf, path->slots[0],
4674                                     struct btrfs_file_extent_item);
4675                 if (btrfs_file_extent_type(leaf, fi) !=
4676                     BTRFS_FILE_EXTENT_REG ||
4677                     btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
4678                         break;
4679
4680                 if (nr == max) {
4681                         struct disk_extent *old = exts;
4682                         max *= 2;
4683                         exts = kzalloc(sizeof(*exts) * max, GFP_NOFS);
4684                         memcpy(exts, old, sizeof(*exts) * nr);
4685                         if (old != *extents)
4686                                 kfree(old);
4687                 }
4688
4689                 exts[nr].disk_bytenr =
4690                         btrfs_file_extent_disk_bytenr(leaf, fi);
4691                 exts[nr].disk_num_bytes =
4692                         btrfs_file_extent_disk_num_bytes(leaf, fi);
4693                 exts[nr].offset = btrfs_file_extent_offset(leaf, fi);
4694                 exts[nr].num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
4695                 exts[nr].ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
4696                 exts[nr].compression = btrfs_file_extent_compression(leaf, fi);
4697                 exts[nr].encryption = btrfs_file_extent_encryption(leaf, fi);
4698                 exts[nr].other_encoding = btrfs_file_extent_other_encoding(leaf,
4699                                                                            fi);
4700                 BUG_ON(exts[nr].offset > 0);
4701                 BUG_ON(exts[nr].compression || exts[nr].encryption);
4702                 BUG_ON(exts[nr].num_bytes != exts[nr].disk_num_bytes);
4703
4704                 cur_pos += exts[nr].num_bytes;
4705                 nr++;
4706
4707                 if (cur_pos + offset >= last_byte)
4708                         break;
4709
4710                 if (no_fragment) {
4711                         ret = 1;
4712                         goto out;
4713                 }
4714                 path->slots[0]++;
4715         }
4716
4717         BUG_ON(cur_pos + offset > last_byte);
4718         if (cur_pos + offset < last_byte) {
4719                 ret = -ENOENT;
4720                 goto out;
4721         }
4722         ret = 0;
4723 out:
4724         btrfs_free_path(path);
4725         if (ret) {
4726                 if (exts != *extents)
4727                         kfree(exts);
4728         } else {
4729                 *extents = exts;
4730                 *nr_extents = nr;
4731         }
4732         return ret;
4733 }
4734
4735 static noinline int replace_one_extent(struct btrfs_trans_handle *trans,
4736                                         struct btrfs_root *root,
4737                                         struct btrfs_path *path,
4738                                         struct btrfs_key *extent_key,
4739                                         struct btrfs_key *leaf_key,
4740                                         struct btrfs_ref_path *ref_path,
4741                                         struct disk_extent *new_extents,
4742                                         int nr_extents)
4743 {
4744         struct extent_buffer *leaf;
4745         struct btrfs_file_extent_item *fi;
4746         struct inode *inode = NULL;
4747         struct btrfs_key key;
4748         u64 lock_start = 0;
4749         u64 lock_end = 0;
4750         u64 num_bytes;
4751         u64 ext_offset;
4752         u64 search_end = (u64)-1;
4753         u32 nritems;
4754         int nr_scaned = 0;
4755         int extent_locked = 0;
4756         int extent_type;
4757         int ret;
4758
4759         memcpy(&key, leaf_key, sizeof(key));
4760         if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
4761                 if (key.objectid < ref_path->owner_objectid ||
4762                     (key.objectid == ref_path->owner_objectid &&
4763                      key.type < BTRFS_EXTENT_DATA_KEY)) {
4764                         key.objectid = ref_path->owner_objectid;
4765                         key.type = BTRFS_EXTENT_DATA_KEY;
4766                         key.offset = 0;
4767                 }
4768         }
4769
4770         while (1) {
4771                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
4772                 if (ret < 0)
4773                         goto out;
4774
4775                 leaf = path->nodes[0];
4776                 nritems = btrfs_header_nritems(leaf);
4777 next:
4778                 if (extent_locked && ret > 0) {
4779                         /*
4780                          * the file extent item was modified by someone
4781                          * before the extent got locked.
4782                          */
4783                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
4784                                       lock_end, GFP_NOFS);
4785                         extent_locked = 0;
4786                 }
4787
4788                 if (path->slots[0] >= nritems) {
4789                         if (++nr_scaned > 2)
4790                                 break;
4791
4792                         BUG_ON(extent_locked);
4793                         ret = btrfs_next_leaf(root, path);
4794                         if (ret < 0)
4795                                 goto out;
4796                         if (ret > 0)
4797                                 break;
4798                         leaf = path->nodes[0];
4799                         nritems = btrfs_header_nritems(leaf);
4800                 }
4801
4802                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4803
4804                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS) {
4805                         if ((key.objectid > ref_path->owner_objectid) ||
4806                             (key.objectid == ref_path->owner_objectid &&
4807                              key.type > BTRFS_EXTENT_DATA_KEY) ||
4808                             key.offset >= search_end)
4809                                 break;
4810                 }
4811
4812                 if (inode && key.objectid != inode->i_ino) {
4813                         BUG_ON(extent_locked);
4814                         btrfs_release_path(root, path);
4815                         mutex_unlock(&inode->i_mutex);
4816                         iput(inode);
4817                         inode = NULL;
4818                         continue;
4819                 }
4820
4821                 if (key.type != BTRFS_EXTENT_DATA_KEY) {
4822                         path->slots[0]++;
4823                         ret = 1;
4824                         goto next;
4825                 }
4826                 fi = btrfs_item_ptr(leaf, path->slots[0],
4827                                     struct btrfs_file_extent_item);
4828                 extent_type = btrfs_file_extent_type(leaf, fi);
4829                 if ((extent_type != BTRFS_FILE_EXTENT_REG &&
4830                      extent_type != BTRFS_FILE_EXTENT_PREALLOC) ||
4831                     (btrfs_file_extent_disk_bytenr(leaf, fi) !=
4832                      extent_key->objectid)) {
4833                         path->slots[0]++;
4834                         ret = 1;
4835                         goto next;
4836                 }
4837
4838                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
4839                 ext_offset = btrfs_file_extent_offset(leaf, fi);
4840
4841                 if (search_end == (u64)-1) {
4842                         search_end = key.offset - ext_offset +
4843                                 btrfs_file_extent_ram_bytes(leaf, fi);
4844                 }
4845
4846                 if (!extent_locked) {
4847                         lock_start = key.offset;
4848                         lock_end = lock_start + num_bytes - 1;
4849                 } else {
4850                         if (lock_start > key.offset ||
4851                             lock_end + 1 < key.offset + num_bytes) {
4852                                 unlock_extent(&BTRFS_I(inode)->io_tree,
4853                                               lock_start, lock_end, GFP_NOFS);
4854                                 extent_locked = 0;
4855                         }
4856                 }
4857
4858                 if (!inode) {
4859                         btrfs_release_path(root, path);
4860
4861                         inode = btrfs_iget_locked(root->fs_info->sb,
4862                                                   key.objectid, root);
4863                         if (inode->i_state & I_NEW) {
4864                                 BTRFS_I(inode)->root = root;
4865                                 BTRFS_I(inode)->location.objectid =
4866                                         key.objectid;
4867                                 BTRFS_I(inode)->location.type =
4868                                         BTRFS_INODE_ITEM_KEY;
4869                                 BTRFS_I(inode)->location.offset = 0;
4870                                 btrfs_read_locked_inode(inode);
4871                                 unlock_new_inode(inode);
4872                         }
4873                         /*
4874                          * some code call btrfs_commit_transaction while
4875                          * holding the i_mutex, so we can't use mutex_lock
4876                          * here.
4877                          */
4878                         if (is_bad_inode(inode) ||
4879                             !mutex_trylock(&inode->i_mutex)) {
4880                                 iput(inode);
4881                                 inode = NULL;
4882                                 key.offset = (u64)-1;
4883                                 goto skip;
4884                         }
4885                 }
4886
4887                 if (!extent_locked) {
4888                         struct btrfs_ordered_extent *ordered;
4889
4890                         btrfs_release_path(root, path);
4891
4892                         lock_extent(&BTRFS_I(inode)->io_tree, lock_start,
4893                                     lock_end, GFP_NOFS);
4894                         ordered = btrfs_lookup_first_ordered_extent(inode,
4895                                                                     lock_end);
4896                         if (ordered &&
4897                             ordered->file_offset <= lock_end &&
4898                             ordered->file_offset + ordered->len > lock_start) {
4899                                 unlock_extent(&BTRFS_I(inode)->io_tree,
4900                                               lock_start, lock_end, GFP_NOFS);
4901                                 btrfs_start_ordered_extent(inode, ordered, 1);
4902                                 btrfs_put_ordered_extent(ordered);
4903                                 key.offset += num_bytes;
4904                                 goto skip;
4905                         }
4906                         if (ordered)
4907                                 btrfs_put_ordered_extent(ordered);
4908
4909                         extent_locked = 1;
4910                         continue;
4911                 }
4912
4913                 if (nr_extents == 1) {
4914                         /* update extent pointer in place */
4915                         btrfs_set_file_extent_disk_bytenr(leaf, fi,
4916                                                 new_extents[0].disk_bytenr);
4917                         btrfs_set_file_extent_disk_num_bytes(leaf, fi,
4918                                                 new_extents[0].disk_num_bytes);
4919                         btrfs_mark_buffer_dirty(leaf);
4920
4921                         btrfs_drop_extent_cache(inode, key.offset,
4922                                                 key.offset + num_bytes - 1, 0);
4923
4924                         ret = btrfs_inc_extent_ref(trans, root,
4925                                                 new_extents[0].disk_bytenr,
4926                                                 new_extents[0].disk_num_bytes,
4927                                                 leaf->start,
4928                                                 root->root_key.objectid,
4929                                                 trans->transid,
4930                                                 key.objectid);
4931                         BUG_ON(ret);
4932
4933                         ret = btrfs_free_extent(trans, root,
4934                                                 extent_key->objectid,
4935                                                 extent_key->offset,
4936                                                 leaf->start,
4937                                                 btrfs_header_owner(leaf),
4938                                                 btrfs_header_generation(leaf),
4939                                                 key.objectid, 0);
4940                         BUG_ON(ret);
4941
4942                         btrfs_release_path(root, path);
4943                         key.offset += num_bytes;
4944                 } else {
4945                         BUG_ON(1);
4946 #if 0
4947                         u64 alloc_hint;
4948                         u64 extent_len;
4949                         int i;
4950                         /*
4951                          * drop old extent pointer at first, then insert the
4952                          * new pointers one bye one
4953                          */
4954                         btrfs_release_path(root, path);
4955                         ret = btrfs_drop_extents(trans, root, inode, key.offset,
4956                                                  key.offset + num_bytes,
4957                                                  key.offset, &alloc_hint);
4958                         BUG_ON(ret);
4959
4960                         for (i = 0; i < nr_extents; i++) {
4961                                 if (ext_offset >= new_extents[i].num_bytes) {
4962                                         ext_offset -= new_extents[i].num_bytes;
4963                                         continue;
4964                                 }
4965                                 extent_len = min(new_extents[i].num_bytes -
4966                                                  ext_offset, num_bytes);
4967
4968                                 ret = btrfs_insert_empty_item(trans, root,
4969                                                               path, &key,
4970                                                               sizeof(*fi));
4971                                 BUG_ON(ret);
4972
4973                                 leaf = path->nodes[0];
4974                                 fi = btrfs_item_ptr(leaf, path->slots[0],
4975                                                 struct btrfs_file_extent_item);
4976                                 btrfs_set_file_extent_generation(leaf, fi,
4977                                                         trans->transid);
4978                                 btrfs_set_file_extent_type(leaf, fi,
4979                                                         BTRFS_FILE_EXTENT_REG);
4980                                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
4981                                                 new_extents[i].disk_bytenr);
4982                                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
4983                                                 new_extents[i].disk_num_bytes);
4984                                 btrfs_set_file_extent_ram_bytes(leaf, fi,
4985                                                 new_extents[i].ram_bytes);
4986
4987                                 btrfs_set_file_extent_compression(leaf, fi,
4988                                                 new_extents[i].compression);
4989                                 btrfs_set_file_extent_encryption(leaf, fi,
4990                                                 new_extents[i].encryption);
4991                                 btrfs_set_file_extent_other_encoding(leaf, fi,
4992                                                 new_extents[i].other_encoding);
4993
4994                                 btrfs_set_file_extent_num_bytes(leaf, fi,
4995                                                         extent_len);
4996                                 ext_offset += new_extents[i].offset;
4997                                 btrfs_set_file_extent_offset(leaf, fi,
4998                                                         ext_offset);
4999                                 btrfs_mark_buffer_dirty(leaf);
5000
5001                                 btrfs_drop_extent_cache(inode, key.offset,
5002                                                 key.offset + extent_len - 1, 0);
5003
5004                                 ret = btrfs_inc_extent_ref(trans, root,
5005                                                 new_extents[i].disk_bytenr,
5006                                                 new_extents[i].disk_num_bytes,
5007                                                 leaf->start,
5008                                                 root->root_key.objectid,
5009                                                 trans->transid, key.objectid);
5010                                 BUG_ON(ret);
5011                                 btrfs_release_path(root, path);
5012
5013                                 inode_add_bytes(inode, extent_len);
5014
5015                                 ext_offset = 0;
5016                                 num_bytes -= extent_len;
5017                                 key.offset += extent_len;
5018
5019                                 if (num_bytes == 0)
5020                                         break;
5021                         }
5022                         BUG_ON(i >= nr_extents);
5023 #endif
5024                 }
5025
5026                 if (extent_locked) {
5027                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
5028                                       lock_end, GFP_NOFS);
5029                         extent_locked = 0;
5030                 }
5031 skip:
5032                 if (ref_path->owner_objectid != BTRFS_MULTIPLE_OBJECTIDS &&
5033                     key.offset >= search_end)
5034                         break;
5035
5036                 cond_resched();
5037         }
5038         ret = 0;
5039 out:
5040         btrfs_release_path(root, path);
5041         if (inode) {
5042                 mutex_unlock(&inode->i_mutex);
5043                 if (extent_locked) {
5044                         unlock_extent(&BTRFS_I(inode)->io_tree, lock_start,
5045                                       lock_end, GFP_NOFS);
5046                 }
5047                 iput(inode);
5048         }
5049         return ret;
5050 }
5051
5052 int btrfs_reloc_tree_cache_ref(struct btrfs_trans_handle *trans,
5053                                struct btrfs_root *root,
5054                                struct extent_buffer *buf, u64 orig_start)
5055 {
5056         int level;
5057         int ret;
5058
5059         BUG_ON(btrfs_header_generation(buf) != trans->transid);
5060         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
5061
5062         level = btrfs_header_level(buf);
5063         if (level == 0) {
5064                 struct btrfs_leaf_ref *ref;
5065                 struct btrfs_leaf_ref *orig_ref;
5066
5067                 orig_ref = btrfs_lookup_leaf_ref(root, orig_start);
5068                 if (!orig_ref)
5069                         return -ENOENT;
5070
5071                 ref = btrfs_alloc_leaf_ref(root, orig_ref->nritems);
5072                 if (!ref) {
5073                         btrfs_free_leaf_ref(root, orig_ref);
5074                         return -ENOMEM;
5075                 }
5076
5077                 ref->nritems = orig_ref->nritems;
5078                 memcpy(ref->extents, orig_ref->extents,
5079                         sizeof(ref->extents[0]) * ref->nritems);
5080
5081                 btrfs_free_leaf_ref(root, orig_ref);
5082
5083                 ref->root_gen = trans->transid;
5084                 ref->bytenr = buf->start;
5085                 ref->owner = btrfs_header_owner(buf);
5086                 ref->generation = btrfs_header_generation(buf);
5087
5088                 ret = btrfs_add_leaf_ref(root, ref, 0);
5089                 WARN_ON(ret);
5090                 btrfs_free_leaf_ref(root, ref);
5091         }
5092         return 0;
5093 }
5094
5095 static noinline int invalidate_extent_cache(struct btrfs_root *root,
5096                                         struct extent_buffer *leaf,
5097                                         struct btrfs_block_group_cache *group,
5098                                         struct btrfs_root *target_root)
5099 {
5100         struct btrfs_key key;
5101         struct inode *inode = NULL;
5102         struct btrfs_file_extent_item *fi;
5103         u64 num_bytes;
5104         u64 skip_objectid = 0;
5105         u32 nritems;
5106         u32 i;
5107
5108         nritems = btrfs_header_nritems(leaf);
5109         for (i = 0; i < nritems; i++) {
5110                 btrfs_item_key_to_cpu(leaf, &key, i);
5111                 if (key.objectid == skip_objectid ||
5112                     key.type != BTRFS_EXTENT_DATA_KEY)
5113                         continue;
5114                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
5115                 if (btrfs_file_extent_type(leaf, fi) ==
5116                     BTRFS_FILE_EXTENT_INLINE)
5117                         continue;
5118                 if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0)
5119                         continue;
5120                 if (!inode || inode->i_ino != key.objectid) {
5121                         iput(inode);
5122                         inode = btrfs_ilookup(target_root->fs_info->sb,
5123                                               key.objectid, target_root, 1);
5124                 }
5125                 if (!inode) {
5126                         skip_objectid = key.objectid;
5127                         continue;
5128                 }
5129                 num_bytes = btrfs_file_extent_num_bytes(leaf, fi);
5130
5131                 lock_extent(&BTRFS_I(inode)->io_tree, key.offset,
5132                             key.offset + num_bytes - 1, GFP_NOFS);
5133                 btrfs_drop_extent_cache(inode, key.offset,
5134                                         key.offset + num_bytes - 1, 1);
5135                 unlock_extent(&BTRFS_I(inode)->io_tree, key.offset,
5136                               key.offset + num_bytes - 1, GFP_NOFS);
5137                 cond_resched();
5138         }
5139         iput(inode);
5140         return 0;
5141 }
5142
5143 static noinline int replace_extents_in_leaf(struct btrfs_trans_handle *trans,
5144                                         struct btrfs_root *root,
5145                                         struct extent_buffer *leaf,
5146                                         struct btrfs_block_group_cache *group,
5147                                         struct inode *reloc_inode)
5148 {
5149         struct btrfs_key key;
5150         struct btrfs_key extent_key;
5151         struct btrfs_file_extent_item *fi;
5152         struct btrfs_leaf_ref *ref;
5153         struct disk_extent *new_extent;
5154         u64 bytenr;
5155         u64 num_bytes;
5156         u32 nritems;
5157         u32 i;
5158         int ext_index;
5159         int nr_extent;
5160         int ret;
5161
5162         new_extent = kmalloc(sizeof(*new_extent), GFP_NOFS);
5163         BUG_ON(!new_extent);
5164
5165         ref = btrfs_lookup_leaf_ref(root, leaf->start);
5166         BUG_ON(!ref);
5167
5168         ext_index = -1;
5169         nritems = btrfs_header_nritems(leaf);
5170         for (i = 0; i < nritems; i++) {
5171                 btrfs_item_key_to_cpu(leaf, &key, i);
5172                 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
5173                         continue;
5174                 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
5175                 if (btrfs_file_extent_type(leaf, fi) ==
5176                     BTRFS_FILE_EXTENT_INLINE)
5177                         continue;
5178                 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
5179                 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
5180                 if (bytenr == 0)
5181                         continue;
5182
5183                 ext_index++;
5184                 if (bytenr >= group->key.objectid + group->key.offset ||
5185                     bytenr + num_bytes <= group->key.objectid)
5186                         continue;
5187
5188                 extent_key.objectid = bytenr;
5189                 extent_key.offset = num_bytes;
5190                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
5191                 nr_extent = 1;
5192                 ret = get_new_locations(reloc_inode, &extent_key,
5193                                         group->key.objectid, 1,
5194                                         &new_extent, &nr_extent);
5195                 if (ret > 0)
5196                         continue;
5197                 BUG_ON(ret < 0);
5198
5199                 BUG_ON(ref->extents[ext_index].bytenr != bytenr);
5200                 BUG_ON(ref->extents[ext_index].num_bytes != num_bytes);
5201                 ref->extents[ext_index].bytenr = new_extent->disk_bytenr;
5202                 ref->extents[ext_index].num_bytes = new_extent->disk_num_bytes;
5203
5204                 btrfs_set_file_extent_disk_bytenr(leaf, fi,
5205                                                 new_extent->disk_bytenr);
5206                 btrfs_set_file_extent_disk_num_bytes(leaf, fi,
5207                                                 new_extent->disk_num_bytes);
5208                 btrfs_mark_buffer_dirty(leaf);
5209
5210                 ret = btrfs_inc_extent_ref(trans, root,
5211                                         new_extent->disk_bytenr,
5212                                         new_extent->disk_num_bytes,
5213                                         leaf->start,
5214                                         root->root_key.objectid,
5215                                         trans->transid, key.objectid);
5216                 BUG_ON(ret);
5217                 ret = btrfs_free_extent(trans, root,
5218                                         bytenr, num_bytes, leaf->start,
5219                                         btrfs_header_owner(leaf),
5220                                         btrfs_header_generation(leaf),
5221                                         key.objectid, 0);
5222                 BUG_ON(ret);
5223                 cond_resched();
5224         }
5225         kfree(new_extent);
5226         BUG_ON(ext_index + 1 != ref->nritems);
5227         btrfs_free_leaf_ref(root, ref);
5228         return 0;
5229 }
5230
5231 int btrfs_free_reloc_root(struct btrfs_trans_handle *trans,
5232                           struct btrfs_root *root)
5233 {
5234         struct btrfs_root *reloc_root;
5235         int ret;
5236
5237         if (root->reloc_root) {
5238                 reloc_root = root->reloc_root;
5239                 root->reloc_root = NULL;
5240                 list_add(&reloc_root->dead_list,
5241                          &root->fs_info->dead_reloc_roots);
5242
5243                 btrfs_set_root_bytenr(&reloc_root->root_item,
5244                                       reloc_root->node->start);
5245                 btrfs_set_root_level(&root->root_item,
5246                                      btrfs_header_level(reloc_root->node));
5247                 memset(&reloc_root->root_item.drop_progress, 0,
5248                         sizeof(struct btrfs_disk_key));
5249                 reloc_root->root_item.drop_level = 0;
5250
5251                 ret = btrfs_update_root(trans, root->fs_info->tree_root,
5252                                         &reloc_root->root_key,
5253                                         &reloc_root->root_item);
5254                 BUG_ON(ret);
5255         }
5256         return 0;
5257 }
5258
5259 int btrfs_drop_dead_reloc_roots(struct btrfs_root *root)
5260 {
5261         struct btrfs_trans_handle *trans;
5262         struct btrfs_root *reloc_root;
5263         struct btrfs_root *prev_root = NULL;
5264         struct list_head dead_roots;
5265         int ret;
5266         unsigned long nr;
5267
5268         INIT_LIST_HEAD(&dead_roots);
5269         list_splice_init(&root->fs_info->dead_reloc_roots, &dead_roots);
5270
5271         while (!list_empty(&dead_roots)) {
5272                 reloc_root = list_entry(dead_roots.prev,
5273                                         struct btrfs_root, dead_list);
5274                 list_del_init(&reloc_root->dead_list);
5275
5276                 BUG_ON(reloc_root->commit_root != NULL);
5277                 while (1) {
5278                         trans = btrfs_join_transaction(root, 1);
5279                         BUG_ON(!trans);
5280
5281                         mutex_lock(&root->fs_info->drop_mutex);
5282                         ret = btrfs_drop_snapshot(trans, reloc_root);
5283                         if (ret != -EAGAIN)
5284                                 break;
5285                         mutex_unlock(&root->fs_info->drop_mutex);
5286
5287                         nr = trans->blocks_used;
5288                         ret = btrfs_end_transaction(trans, root);
5289                         BUG_ON(ret);
5290                         btrfs_btree_balance_dirty(root, nr);
5291                 }
5292
5293                 free_extent_buffer(reloc_root->node);
5294
5295                 ret = btrfs_del_root(trans, root->fs_info->tree_root,
5296                                      &reloc_root->root_key);
5297                 BUG_ON(ret);
5298                 mutex_unlock(&root->fs_info->drop_mutex);
5299
5300                 nr = trans->blocks_used;
5301                 ret = btrfs_end_transaction(trans, root);
5302                 BUG_ON(ret);
5303                 btrfs_btree_balance_dirty(root, nr);
5304
5305                 kfree(prev_root);
5306                 prev_root = reloc_root;
5307         }
5308         if (prev_root) {
5309                 btrfs_remove_leaf_refs(prev_root, (u64)-1, 0);
5310                 kfree(prev_root);
5311         }
5312         return 0;
5313 }
5314
5315 int btrfs_add_dead_reloc_root(struct btrfs_root *root)
5316 {
5317         list_add(&root->dead_list, &root->fs_info->dead_reloc_roots);
5318         return 0;
5319 }
5320
5321 int btrfs_cleanup_reloc_trees(struct btrfs_root *root)
5322 {
5323         struct btrfs_root *reloc_root;
5324         struct btrfs_trans_handle *trans;
5325         struct btrfs_key location;
5326         int found;
5327         int ret;
5328
5329         mutex_lock(&root->fs_info->tree_reloc_mutex);
5330         ret = btrfs_find_dead_roots(root, BTRFS_TREE_RELOC_OBJECTID, NULL);
5331         BUG_ON(ret);
5332         found = !list_empty(&root->fs_info->dead_reloc_roots);
5333         mutex_unlock(&root->fs_info->tree_reloc_mutex);
5334
5335         if (found) {
5336                 trans = btrfs_start_transaction(root, 1);
5337                 BUG_ON(!trans);
5338                 ret = btrfs_commit_transaction(trans, root);
5339                 BUG_ON(ret);
5340         }
5341
5342         location.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
5343         location.offset = (u64)-1;
5344         location.type = BTRFS_ROOT_ITEM_KEY;
5345
5346         reloc_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
5347         BUG_ON(!reloc_root);
5348         btrfs_orphan_cleanup(reloc_root);
5349         return 0;
5350 }
5351
5352 static noinline int init_reloc_tree(struct btrfs_trans_handle *trans,
5353                                     struct btrfs_root *root)
5354 {
5355         struct btrfs_root *reloc_root;
5356         struct extent_buffer *eb;
5357         struct btrfs_root_item *root_item;
5358         struct btrfs_key root_key;
5359         int ret;
5360
5361         BUG_ON(!root->ref_cows);
5362         if (root->reloc_root)
5363                 return 0;
5364
5365         root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
5366         BUG_ON(!root_item);
5367
5368         ret = btrfs_copy_root(trans, root, root->commit_root,
5369                               &eb, BTRFS_TREE_RELOC_OBJECTID);
5370         BUG_ON(ret);
5371
5372         root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
5373         root_key.offset = root->root_key.objectid;
5374         root_key.type = BTRFS_ROOT_ITEM_KEY;
5375
5376         memcpy(root_item, &root->root_item, sizeof(root_item));
5377         btrfs_set_root_refs(root_item, 0);
5378         btrfs_set_root_bytenr(root_item, eb->start);
5379         btrfs_set_root_level(root_item, btrfs_header_level(eb));
5380         btrfs_set_root_generation(root_item, trans->transid);
5381
5382         btrfs_tree_unlock(eb);
5383         free_extent_buffer(eb);
5384
5385         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
5386                                 &root_key, root_item);
5387         BUG_ON(ret);
5388         kfree(root_item);
5389
5390         reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
5391                                                  &root_key);
5392         BUG_ON(!reloc_root);
5393         reloc_root->last_trans = trans->transid;
5394         reloc_root->commit_root = NULL;
5395         reloc_root->ref_tree = &root->fs_info->reloc_ref_tree;
5396
5397         root->reloc_root = reloc_root;
5398         return 0;
5399 }
5400
5401 /*
5402  * Core function of space balance.
5403  *
5404  * The idea is using reloc trees to relocate tree blocks in reference
5405  * counted roots. There is one reloc tree for each subvol, and all
5406  * reloc trees share same root key objectid. Reloc trees are snapshots
5407  * of the latest committed roots of subvols (root->commit_root).
5408  *
5409  * To relocate a tree block referenced by a subvol, there are two steps.
5410  * COW the block through subvol's reloc tree, then update block pointer
5411  * in the subvol to point to the new block. Since all reloc trees share
5412  * same root key objectid, doing special handing for tree blocks owned
5413  * by them is easy. Once a tree block has been COWed in one reloc tree,
5414  * we can use the resulting new block directly when the same block is
5415  * required to COW again through other reloc trees. By this way, relocated
5416  * tree blocks are shared between reloc trees, so they are also shared
5417  * between subvols.
5418  */
5419 static noinline int relocate_one_path(struct btrfs_trans_handle *trans,
5420                                       struct btrfs_root *root,
5421                                       struct btrfs_path *path,
5422                                       struct btrfs_key *first_key,
5423                                       struct btrfs_ref_path *ref_path,
5424                                       struct btrfs_block_group_cache *group,
5425                                       struct inode *reloc_inode)
5426 {
5427         struct btrfs_root *reloc_root;
5428         struct extent_buffer *eb = NULL;
5429         struct btrfs_key *keys;
5430         u64 *nodes;
5431         int level;
5432         int shared_level;
5433         int lowest_level = 0;
5434         int ret;
5435
5436         if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID)
5437                 lowest_level = ref_path->owner_objectid;
5438
5439         if (!root->ref_cows) {
5440                 path->lowest_level = lowest_level;
5441                 ret = btrfs_search_slot(trans, root, first_key, path, 0, 1);
5442                 BUG_ON(ret < 0);
5443                 path->lowest_level = 0;
5444                 btrfs_release_path(root, path);
5445                 return 0;
5446         }
5447
5448         mutex_lock(&root->fs_info->tree_reloc_mutex);
5449         ret = init_reloc_tree(trans, root);
5450         BUG_ON(ret);
5451         reloc_root = root->reloc_root;
5452
5453         shared_level = ref_path->shared_level;
5454         ref_path->shared_level = BTRFS_MAX_LEVEL - 1;
5455
5456         keys = ref_path->node_keys;
5457         nodes = ref_path->new_nodes;
5458         memset(&keys[shared_level + 1], 0,
5459                sizeof(*keys) * (BTRFS_MAX_LEVEL - shared_level - 1));
5460         memset(&nodes[shared_level + 1], 0,
5461                sizeof(*nodes) * (BTRFS_MAX_LEVEL - shared_level - 1));
5462
5463         if (nodes[lowest_level] == 0) {
5464                 path->lowest_level = lowest_level;
5465                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
5466                                         0, 1);
5467                 BUG_ON(ret);
5468                 for (level = lowest_level; level < BTRFS_MAX_LEVEL; level++) {
5469                         eb = path->nodes[level];
5470                         if (!eb || eb == reloc_root->node)
5471                                 break;
5472                         nodes[level] = eb->start;
5473                         if (level == 0)
5474                                 btrfs_item_key_to_cpu(eb, &keys[level], 0);
5475                         else
5476                                 btrfs_node_key_to_cpu(eb, &keys[level], 0);
5477                 }
5478                 if (nodes[0] &&
5479                     ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5480                         eb = path->nodes[0];
5481                         ret = replace_extents_in_leaf(trans, reloc_root, eb,
5482                                                       group, reloc_inode);
5483                         BUG_ON(ret);
5484                 }
5485                 btrfs_release_path(reloc_root, path);
5486         } else {
5487                 ret = btrfs_merge_path(trans, reloc_root, keys, nodes,
5488                                        lowest_level);
5489                 BUG_ON(ret);
5490         }
5491
5492         /*
5493          * replace tree blocks in the fs tree with tree blocks in
5494          * the reloc tree.
5495          */
5496         ret = btrfs_merge_path(trans, root, keys, nodes, lowest_level);
5497         BUG_ON(ret < 0);
5498
5499         if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5500                 ret = btrfs_search_slot(trans, reloc_root, first_key, path,
5501                                         0, 0);
5502                 BUG_ON(ret);
5503                 extent_buffer_get(path->nodes[0]);
5504                 eb = path->nodes[0];
5505                 btrfs_release_path(reloc_root, path);
5506                 ret = invalidate_extent_cache(reloc_root, eb, group, root);
5507                 BUG_ON(ret);
5508                 free_extent_buffer(eb);
5509         }
5510
5511         mutex_unlock(&root->fs_info->tree_reloc_mutex);
5512         path->lowest_level = 0;
5513         return 0;
5514 }
5515
5516 static noinline int relocate_tree_block(struct btrfs_trans_handle *trans,
5517                                         struct btrfs_root *root,
5518                                         struct btrfs_path *path,
5519                                         struct btrfs_key *first_key,
5520                                         struct btrfs_ref_path *ref_path)
5521 {
5522         int ret;
5523
5524         ret = relocate_one_path(trans, root, path, first_key,
5525                                 ref_path, NULL, NULL);
5526         BUG_ON(ret);
5527
5528         if (root == root->fs_info->extent_root)
5529                 btrfs_extent_post_op(trans, root);
5530
5531         return 0;
5532 }
5533
5534 static noinline int del_extent_zero(struct btrfs_trans_handle *trans,
5535                                     struct btrfs_root *extent_root,
5536                                     struct btrfs_path *path,
5537                                     struct btrfs_key *extent_key)
5538 {
5539         int ret;
5540
5541         ret = btrfs_search_slot(trans, extent_root, extent_key, path, -1, 1);
5542         if (ret)
5543                 goto out;
5544         ret = btrfs_del_item(trans, extent_root, path);
5545 out:
5546         btrfs_release_path(extent_root, path);
5547         return ret;
5548 }
5549
5550 static noinline struct btrfs_root *read_ref_root(struct btrfs_fs_info *fs_info,
5551                                                 struct btrfs_ref_path *ref_path)
5552 {
5553         struct btrfs_key root_key;
5554
5555         root_key.objectid = ref_path->root_objectid;
5556         root_key.type = BTRFS_ROOT_ITEM_KEY;
5557         if (is_cowonly_root(ref_path->root_objectid))
5558                 root_key.offset = 0;
5559         else
5560                 root_key.offset = (u64)-1;
5561
5562         return btrfs_read_fs_root_no_name(fs_info, &root_key);
5563 }
5564
5565 static noinline int relocate_one_extent(struct btrfs_root *extent_root,
5566                                         struct btrfs_path *path,
5567                                         struct btrfs_key *extent_key,
5568                                         struct btrfs_block_group_cache *group,
5569                                         struct inode *reloc_inode, int pass)
5570 {
5571         struct btrfs_trans_handle *trans;
5572         struct btrfs_root *found_root;
5573         struct btrfs_ref_path *ref_path = NULL;
5574         struct disk_extent *new_extents = NULL;
5575         int nr_extents = 0;
5576         int loops;
5577         int ret;
5578         int level;
5579         struct btrfs_key first_key;
5580         u64 prev_block = 0;
5581
5582
5583         trans = btrfs_start_transaction(extent_root, 1);
5584         BUG_ON(!trans);
5585
5586         if (extent_key->objectid == 0) {
5587                 ret = del_extent_zero(trans, extent_root, path, extent_key);
5588                 goto out;
5589         }
5590
5591         ref_path = kmalloc(sizeof(*ref_path), GFP_NOFS);
5592         if (!ref_path) {
5593                 ret = -ENOMEM;
5594                 goto out;
5595         }
5596
5597         for (loops = 0; ; loops++) {
5598                 if (loops == 0) {
5599                         ret = btrfs_first_ref_path(trans, extent_root, ref_path,
5600                                                    extent_key->objectid);
5601                 } else {
5602                         ret = btrfs_next_ref_path(trans, extent_root, ref_path);
5603                 }
5604                 if (ret < 0)
5605                         goto out;
5606                 if (ret > 0)
5607                         break;
5608
5609                 if (ref_path->root_objectid == BTRFS_TREE_LOG_OBJECTID ||
5610                     ref_path->root_objectid == BTRFS_TREE_RELOC_OBJECTID)
5611                         continue;
5612
5613                 found_root = read_ref_root(extent_root->fs_info, ref_path);
5614                 BUG_ON(!found_root);
5615                 /*
5616                  * for reference counted tree, only process reference paths
5617                  * rooted at the latest committed root.
5618                  */
5619                 if (found_root->ref_cows &&
5620                     ref_path->root_generation != found_root->root_key.offset)
5621                         continue;
5622
5623                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5624                         if (pass == 0) {
5625                                 /*
5626                                  * copy data extents to new locations
5627                                  */
5628                                 u64 group_start = group->key.objectid;
5629                                 ret = relocate_data_extent(reloc_inode,
5630                                                            extent_key,
5631                                                            group_start);
5632                                 if (ret < 0)
5633                                         goto out;
5634                                 break;
5635                         }
5636                         level = 0;
5637                 } else {
5638                         level = ref_path->owner_objectid;
5639                 }
5640
5641                 if (prev_block != ref_path->nodes[level]) {
5642                         struct extent_buffer *eb;
5643                         u64 block_start = ref_path->nodes[level];
5644                         u64 block_size = btrfs_level_size(found_root, level);
5645
5646                         eb = read_tree_block(found_root, block_start,
5647                                              block_size, 0);
5648                         btrfs_tree_lock(eb);
5649                         BUG_ON(level != btrfs_header_level(eb));
5650
5651                         if (level == 0)
5652                                 btrfs_item_key_to_cpu(eb, &first_key, 0);
5653                         else
5654                                 btrfs_node_key_to_cpu(eb, &first_key, 0);
5655
5656                         btrfs_tree_unlock(eb);
5657                         free_extent_buffer(eb);
5658                         prev_block = block_start;
5659                 }
5660
5661                 mutex_lock(&extent_root->fs_info->trans_mutex);
5662                 btrfs_record_root_in_trans(found_root);
5663                 mutex_unlock(&extent_root->fs_info->trans_mutex);
5664                 if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
5665                         /*
5666                          * try to update data extent references while
5667                          * keeping metadata shared between snapshots.
5668                          */
5669                         if (pass == 1) {
5670                                 ret = relocate_one_path(trans, found_root,
5671                                                 path, &first_key, ref_path,
5672                                                 group, reloc_inode);
5673                                 if (ret < 0)
5674                                         goto out;
5675                                 continue;
5676                         }
5677                         /*
5678                          * use fallback method to process the remaining
5679                          * references.
5680                          */
5681                         if (!new_extents) {
5682                                 u64 group_start = group->key.objectid;
5683                                 new_extents = kmalloc(sizeof(*new_extents),
5684                                                       GFP_NOFS);
5685                                 nr_extents = 1;
5686                                 ret = get_new_locations(reloc_inode,
5687                                                         extent_key,
5688                                                         group_start, 1,
5689                                                         &new_extents,
5690                                                         &nr_extents);
5691                                 if (ret)
5692                                         goto out;
5693                         }
5694                         ret = replace_one_extent(trans, found_root,
5695                                                 path, extent_key,
5696                                                 &first_key, ref_path,
5697                                                 new_extents, nr_extents);
5698                 } else {
5699                         ret = relocate_tree_block(trans, found_root, path,
5700                                                   &first_key, ref_path);
5701                 }
5702                 if (ret < 0)
5703                         goto out;
5704         }
5705         ret = 0;
5706 out:
5707         btrfs_end_transaction(trans, extent_root);
5708         kfree(new_extents);
5709         kfree(ref_path);
5710         return ret;
5711 }
5712
5713 static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
5714 {
5715         u64 num_devices;
5716         u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
5717                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
5718
5719         num_devices = root->fs_info->fs_devices->rw_devices;
5720         if (num_devices == 1) {
5721                 stripped |= BTRFS_BLOCK_GROUP_DUP;
5722                 stripped = flags & ~stripped;
5723
5724                 /* turn raid0 into single device chunks */
5725                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
5726                         return stripped;
5727
5728                 /* turn mirroring into duplication */
5729                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
5730                              BTRFS_BLOCK_GROUP_RAID10))
5731                         return stripped | BTRFS_BLOCK_GROUP_DUP;
5732                 return flags;
5733         } else {
5734                 /* they already had raid on here, just return */
5735                 if (flags & stripped)
5736                         return flags;
5737
5738                 stripped |= BTRFS_BLOCK_GROUP_DUP;
5739                 stripped = flags & ~stripped;
5740
5741                 /* switch duplicated blocks with raid1 */
5742                 if (flags & BTRFS_BLOCK_GROUP_DUP)
5743                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
5744
5745                 /* turn single device chunks into raid0 */
5746                 return stripped | BTRFS_BLOCK_GROUP_RAID0;
5747         }
5748         return flags;
5749 }
5750
5751 static int __alloc_chunk_for_shrink(struct btrfs_root *root,
5752                      struct btrfs_block_group_cache *shrink_block_group,
5753                      int force)
5754 {
5755         struct btrfs_trans_handle *trans;
5756         u64 new_alloc_flags;
5757         u64 calc;
5758
5759         spin_lock(&shrink_block_group->lock);
5760         if (btrfs_block_group_used(&shrink_block_group->item) > 0) {
5761                 spin_unlock(&shrink_block_group->lock);
5762
5763                 trans = btrfs_start_transaction(root, 1);
5764                 spin_lock(&shrink_block_group->lock);
5765
5766                 new_alloc_flags = update_block_group_flags(root,
5767                                                    shrink_block_group->flags);
5768                 if (new_alloc_flags != shrink_block_group->flags) {
5769                         calc =
5770                              btrfs_block_group_used(&shrink_block_group->item);
5771                 } else {
5772                         calc = shrink_block_group->key.offset;
5773                 }
5774                 spin_unlock(&shrink_block_group->lock);
5775
5776                 do_chunk_alloc(trans, root->fs_info->extent_root,
5777                                calc + 2 * 1024 * 1024, new_alloc_flags, force);
5778
5779                 btrfs_end_transaction(trans, root);
5780         } else
5781                 spin_unlock(&shrink_block_group->lock);
5782         return 0;
5783 }
5784
5785 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
5786                                  struct btrfs_root *root,
5787                                  u64 objectid, u64 size)
5788 {
5789         struct btrfs_path *path;
5790         struct btrfs_inode_item *item;
5791         struct extent_buffer *leaf;
5792         int ret;
5793
5794         path = btrfs_alloc_path();
5795         if (!path)
5796                 return -ENOMEM;
5797
5798         ret = btrfs_insert_empty_inode(trans, root, path, objectid);
5799         if (ret)
5800                 goto out;
5801
5802         leaf = path->nodes[0];
5803         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
5804         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
5805         btrfs_set_inode_generation(leaf, item, 1);
5806         btrfs_set_inode_size(leaf, item, size);
5807         btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
5808         btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS);
5809         btrfs_mark_buffer_dirty(leaf);
5810         btrfs_release_path(root, path);
5811 out:
5812         btrfs_free_path(path);
5813         return ret;
5814 }
5815
5816 static noinline struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
5817                                         struct btrfs_block_group_cache *group)
5818 {
5819         struct inode *inode = NULL;
5820         struct btrfs_trans_handle *trans;
5821         struct btrfs_root *root;
5822         struct btrfs_key root_key;
5823         u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
5824         int err = 0;
5825
5826         root_key.objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
5827         root_key.type = BTRFS_ROOT_ITEM_KEY;
5828         root_key.offset = (u64)-1;
5829         root = btrfs_read_fs_root_no_name(fs_info, &root_key);
5830         if (IS_ERR(root))
5831                 return ERR_CAST(root);
5832
5833         trans = btrfs_start_transaction(root, 1);
5834         BUG_ON(!trans);
5835
5836         err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
5837         if (err)
5838                 goto out;
5839
5840         err = __insert_orphan_inode(trans, root, objectid, group->key.offset);
5841         BUG_ON(err);
5842
5843         err = btrfs_insert_file_extent(trans, root, objectid, 0, 0, 0,
5844                                        group->key.offset, 0, group->key.offset,
5845                                        0, 0, 0);
5846         BUG_ON(err);
5847
5848         inode = btrfs_iget_locked(root->fs_info->sb, objectid, root);
5849         if (inode->i_state & I_NEW) {
5850                 BTRFS_I(inode)->root = root;
5851                 BTRFS_I(inode)->location.objectid = objectid;
5852                 BTRFS_I(inode)->location.type = BTRFS_INODE_ITEM_KEY;
5853                 BTRFS_I(inode)->location.offset = 0;
5854                 btrfs_read_locked_inode(inode);
5855                 unlock_new_inode(inode);
5856                 BUG_ON(is_bad_inode(inode));
5857         } else {
5858                 BUG_ON(1);
5859         }
5860         BTRFS_I(inode)->index_cnt = group->key.objectid;
5861
5862         err = btrfs_orphan_add(trans, inode);
5863 out:
5864         btrfs_end_transaction(trans, root);
5865         if (err) {
5866                 if (inode)
5867                         iput(inode);
5868                 inode = ERR_PTR(err);
5869         }
5870         return inode;
5871 }
5872
5873 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
5874 {
5875
5876         struct btrfs_ordered_sum *sums;
5877         struct btrfs_sector_sum *sector_sum;
5878         struct btrfs_ordered_extent *ordered;
5879         struct btrfs_root *root = BTRFS_I(inode)->root;
5880         struct list_head list;
5881         size_t offset;
5882         int ret;
5883         u64 disk_bytenr;
5884
5885         INIT_LIST_HEAD(&list);
5886
5887         ordered = btrfs_lookup_ordered_extent(inode, file_pos);
5888         BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
5889
5890         disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
5891         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
5892                                        disk_bytenr + len - 1, &list);
5893
5894         while (!list_empty(&list)) {
5895                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
5896                 list_del_init(&sums->list);
5897
5898                 sector_sum = sums->sums;
5899                 sums->bytenr = ordered->start;
5900
5901                 offset = 0;
5902                 while (offset < sums->len) {
5903                         sector_sum->bytenr += ordered->start - disk_bytenr;
5904                         sector_sum++;
5905                         offset += root->sectorsize;
5906                 }
5907
5908                 btrfs_add_ordered_sum(inode, ordered, sums);
5909         }
5910         btrfs_put_ordered_extent(ordered);
5911         return 0;
5912 }
5913
5914 int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start)
5915 {
5916         struct btrfs_trans_handle *trans;
5917         struct btrfs_path *path;
5918         struct btrfs_fs_info *info = root->fs_info;
5919         struct extent_buffer *leaf;
5920         struct inode *reloc_inode;
5921         struct btrfs_block_group_cache *block_group;
5922         struct btrfs_key key;
5923         u64 skipped;
5924         u64 cur_byte;
5925         u64 total_found;
5926         u32 nritems;
5927         int ret;
5928         int progress;
5929         int pass = 0;
5930
5931         root = root->fs_info->extent_root;
5932
5933         block_group = btrfs_lookup_block_group(info, group_start);
5934         BUG_ON(!block_group);
5935
5936         printk(KERN_INFO "btrfs relocating block group %llu flags %llu\n",
5937                (unsigned long long)block_group->key.objectid,
5938                (unsigned long long)block_group->flags);
5939
5940         path = btrfs_alloc_path();
5941         BUG_ON(!path);
5942
5943         reloc_inode = create_reloc_inode(info, block_group);
5944         BUG_ON(IS_ERR(reloc_inode));
5945
5946         __alloc_chunk_for_shrink(root, block_group, 1);
5947         set_block_group_readonly(block_group);
5948
5949         btrfs_start_delalloc_inodes(info->tree_root);
5950         btrfs_wait_ordered_extents(info->tree_root, 0);
5951 again:
5952         skipped = 0;
5953         total_found = 0;
5954         progress = 0;
5955         key.objectid = block_group->key.objectid;
5956         key.offset = 0;
5957         key.type = 0;
5958         cur_byte = key.objectid;
5959
5960         trans = btrfs_start_transaction(info->tree_root, 1);
5961         btrfs_commit_transaction(trans, info->tree_root);
5962
5963         mutex_lock(&root->fs_info->cleaner_mutex);
5964         btrfs_clean_old_snapshots(info->tree_root);
5965         btrfs_remove_leaf_refs(info->tree_root, (u64)-1, 1);
5966         mutex_unlock(&root->fs_info->cleaner_mutex);
5967
5968         while (1) {
5969                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5970                 if (ret < 0)
5971                         goto out;
5972 next:
5973                 leaf = path->nodes[0];
5974                 nritems = btrfs_header_nritems(leaf);
5975                 if (path->slots[0] >= nritems) {
5976                         ret = btrfs_next_leaf(root, path);
5977                         if (ret < 0)
5978                                 goto out;
5979                         if (ret == 1) {
5980                                 ret = 0;
5981                                 break;
5982                         }
5983                         leaf = path->nodes[0];
5984                         nritems = btrfs_header_nritems(leaf);
5985                 }
5986
5987                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
5988
5989                 if (key.objectid >= block_group->key.objectid +
5990                     block_group->key.offset)
5991                         break;
5992
5993                 if (progress && need_resched()) {
5994                         btrfs_release_path(root, path);
5995                         cond_resched();
5996                         progress = 0;
5997                         continue;
5998                 }
5999                 progress = 1;
6000
6001                 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY ||
6002                     key.objectid + key.offset <= cur_byte) {
6003                         path->slots[0]++;
6004                         goto next;
6005                 }
6006
6007                 total_found++;
6008                 cur_byte = key.objectid + key.offset;
6009                 btrfs_release_path(root, path);
6010
6011                 __alloc_chunk_for_shrink(root, block_group, 0);
6012                 ret = relocate_one_extent(root, path, &key, block_group,
6013                                           reloc_inode, pass);
6014                 BUG_ON(ret < 0);
6015                 if (ret > 0)
6016                         skipped++;
6017
6018                 key.objectid = cur_byte;
6019                 key.type = 0;
6020                 key.offset = 0;
6021         }
6022
6023         btrfs_release_path(root, path);
6024
6025         if (pass == 0) {
6026                 btrfs_wait_ordered_range(reloc_inode, 0, (u64)-1);
6027                 invalidate_mapping_pages(reloc_inode->i_mapping, 0, -1);
6028         }
6029
6030         if (total_found > 0) {
6031                 printk(KERN_INFO "btrfs found %llu extents in pass %d\n",
6032                        (unsigned long long)total_found, pass);
6033                 pass++;
6034                 if (total_found == skipped && pass > 2) {
6035                         iput(reloc_inode);
6036                         reloc_inode = create_reloc_inode(info, block_group);
6037                         pass = 0;
6038                 }
6039                 goto again;
6040         }
6041
6042         /* delete reloc_inode */
6043         iput(reloc_inode);
6044
6045         /* unpin extents in this range */
6046         trans = btrfs_start_transaction(info->tree_root, 1);
6047         btrfs_commit_transaction(trans, info->tree_root);
6048
6049         spin_lock(&block_group->lock);
6050         WARN_ON(block_group->pinned > 0);
6051         WARN_ON(block_group->reserved > 0);
6052         WARN_ON(btrfs_block_group_used(&block_group->item) > 0);
6053         spin_unlock(&block_group->lock);
6054         put_block_group(block_group);
6055         ret = 0;
6056 out:
6057         btrfs_free_path(path);
6058         return ret;
6059 }
6060
6061 static int find_first_block_group(struct btrfs_root *root,
6062                 struct btrfs_path *path, struct btrfs_key *key)
6063 {
6064         int ret = 0;
6065         struct btrfs_key found_key;
6066         struct extent_buffer *leaf;
6067         int slot;
6068
6069         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
6070         if (ret < 0)
6071                 goto out;
6072
6073         while (1) {
6074                 slot = path->slots[0];
6075                 leaf = path->nodes[0];
6076                 if (slot >= btrfs_header_nritems(leaf)) {
6077                         ret = btrfs_next_leaf(root, path);
6078                         if (ret == 0)
6079                                 continue;
6080                         if (ret < 0)
6081                                 goto out;
6082                         break;
6083                 }
6084                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6085
6086                 if (found_key.objectid >= key->objectid &&
6087                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
6088                         ret = 0;
6089                         goto out;
6090                 }
6091                 path->slots[0]++;
6092         }
6093         ret = -ENOENT;
6094 out:
6095         return ret;
6096 }
6097
6098 int btrfs_free_block_groups(struct btrfs_fs_info *info)
6099 {
6100         struct btrfs_block_group_cache *block_group;
6101         struct rb_node *n;
6102
6103         spin_lock(&info->block_group_cache_lock);
6104         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
6105                 block_group = rb_entry(n, struct btrfs_block_group_cache,
6106                                        cache_node);
6107                 rb_erase(&block_group->cache_node,
6108                          &info->block_group_cache_tree);
6109                 spin_unlock(&info->block_group_cache_lock);
6110
6111                 btrfs_remove_free_space_cache(block_group);
6112                 down_write(&block_group->space_info->groups_sem);
6113                 list_del(&block_group->list);
6114                 up_write(&block_group->space_info->groups_sem);
6115
6116                 WARN_ON(atomic_read(&block_group->count) != 1);
6117                 kfree(block_group);
6118
6119                 spin_lock(&info->block_group_cache_lock);
6120         }
6121         spin_unlock(&info->block_group_cache_lock);
6122         return 0;
6123 }
6124
6125 int btrfs_read_block_groups(struct btrfs_root *root)
6126 {
6127         struct btrfs_path *path;
6128         int ret;
6129         struct btrfs_block_group_cache *cache;
6130         struct btrfs_fs_info *info = root->fs_info;
6131         struct btrfs_space_info *space_info;
6132         struct btrfs_key key;
6133         struct btrfs_key found_key;
6134         struct extent_buffer *leaf;
6135
6136         root = info->extent_root;
6137         key.objectid = 0;
6138         key.offset = 0;
6139         btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
6140         path = btrfs_alloc_path();
6141         if (!path)
6142                 return -ENOMEM;
6143
6144         while (1) {
6145                 ret = find_first_block_group(root, path, &key);
6146                 if (ret > 0) {
6147                         ret = 0;
6148                         goto error;
6149                 }
6150                 if (ret != 0)
6151                         goto error;
6152
6153                 leaf = path->nodes[0];
6154                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
6155                 cache = kzalloc(sizeof(*cache), GFP_NOFS);
6156                 if (!cache) {
6157                         ret = -ENOMEM;
6158                         break;
6159                 }
6160
6161                 atomic_set(&cache->count, 1);
6162                 spin_lock_init(&cache->lock);
6163                 mutex_init(&cache->alloc_mutex);
6164                 mutex_init(&cache->cache_mutex);
6165                 INIT_LIST_HEAD(&cache->list);
6166                 read_extent_buffer(leaf, &cache->item,
6167                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
6168                                    sizeof(cache->item));
6169                 memcpy(&cache->key, &found_key, sizeof(found_key));
6170
6171                 key.objectid = found_key.objectid + found_key.offset;
6172                 btrfs_release_path(root, path);
6173                 cache->flags = btrfs_block_group_flags(&cache->item);
6174
6175                 ret = update_space_info(info, cache->flags, found_key.offset,
6176                                         btrfs_block_group_used(&cache->item),
6177                                         &space_info);
6178                 BUG_ON(ret);
6179                 cache->space_info = space_info;
6180                 down_write(&space_info->groups_sem);
6181                 list_add_tail(&cache->list, &space_info->block_groups);
6182                 up_write(&space_info->groups_sem);
6183
6184                 ret = btrfs_add_block_group_cache(root->fs_info, cache);
6185                 BUG_ON(ret);
6186
6187                 set_avail_alloc_bits(root->fs_info, cache->flags);
6188                 if (btrfs_chunk_readonly(root, cache->key.objectid))
6189                         set_block_group_readonly(cache);
6190         }
6191         ret = 0;
6192 error:
6193         btrfs_free_path(path);
6194         return ret;
6195 }
6196
6197 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
6198                            struct btrfs_root *root, u64 bytes_used,
6199                            u64 type, u64 chunk_objectid, u64 chunk_offset,
6200                            u64 size)
6201 {
6202         int ret;
6203         struct btrfs_root *extent_root;
6204         struct btrfs_block_group_cache *cache;
6205
6206         extent_root = root->fs_info->extent_root;
6207
6208         root->fs_info->last_trans_new_blockgroup = trans->transid;
6209
6210         cache = kzalloc(sizeof(*cache), GFP_NOFS);
6211         if (!cache)
6212                 return -ENOMEM;
6213
6214         cache->key.objectid = chunk_offset;
6215         cache->key.offset = size;
6216         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
6217         atomic_set(&cache->count, 1);
6218         spin_lock_init(&cache->lock);
6219         mutex_init(&cache->alloc_mutex);
6220         mutex_init(&cache->cache_mutex);
6221         INIT_LIST_HEAD(&cache->list);
6222
6223         btrfs_set_block_group_used(&cache->item, bytes_used);
6224         btrfs_set_block_group_chunk_objectid(&cache->item, chunk_objectid);
6225         cache->flags = type;
6226         btrfs_set_block_group_flags(&cache->item, type);
6227
6228         ret = update_space_info(root->fs_info, cache->flags, size, bytes_used,
6229                                 &cache->space_info);
6230         BUG_ON(ret);
6231         down_write(&cache->space_info->groups_sem);
6232         list_add_tail(&cache->list, &cache->space_info->block_groups);
6233         up_write(&cache->space_info->groups_sem);
6234
6235         ret = btrfs_add_block_group_cache(root->fs_info, cache);
6236         BUG_ON(ret);
6237
6238         ret = btrfs_insert_item(trans, extent_root, &cache->key, &cache->item,
6239                                 sizeof(cache->item));
6240         BUG_ON(ret);
6241
6242         finish_current_insert(trans, extent_root, 0);
6243         ret = del_pending_extents(trans, extent_root, 0);
6244         BUG_ON(ret);
6245         set_avail_alloc_bits(extent_root->fs_info, type);
6246
6247         return 0;
6248 }
6249
6250 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
6251                              struct btrfs_root *root, u64 group_start)
6252 {
6253         struct btrfs_path *path;
6254         struct btrfs_block_group_cache *block_group;
6255         struct btrfs_key key;
6256         int ret;
6257
6258         root = root->fs_info->extent_root;
6259
6260         block_group = btrfs_lookup_block_group(root->fs_info, group_start);
6261         BUG_ON(!block_group);
6262         BUG_ON(!block_group->ro);
6263
6264         memcpy(&key, &block_group->key, sizeof(key));
6265
6266         path = btrfs_alloc_path();
6267         BUG_ON(!path);
6268
6269         spin_lock(&root->fs_info->block_group_cache_lock);
6270         rb_erase(&block_group->cache_node,
6271                  &root->fs_info->block_group_cache_tree);
6272         spin_unlock(&root->fs_info->block_group_cache_lock);
6273         btrfs_remove_free_space_cache(block_group);
6274         down_write(&block_group->space_info->groups_sem);
6275         list_del(&block_group->list);
6276         up_write(&block_group->space_info->groups_sem);
6277
6278         spin_lock(&block_group->space_info->lock);
6279         block_group->space_info->total_bytes -= block_group->key.offset;
6280         block_group->space_info->bytes_readonly -= block_group->key.offset;
6281         spin_unlock(&block_group->space_info->lock);
6282         block_group->space_info->full = 0;
6283
6284         put_block_group(block_group);
6285         put_block_group(block_group);
6286
6287         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
6288         if (ret > 0)
6289                 ret = -EIO;
6290         if (ret < 0)
6291                 goto out;
6292
6293         ret = btrfs_del_item(trans, root, path);
6294 out:
6295         btrfs_free_path(path);
6296         return ret;
6297 }