1 /* 2 * Copyright (C) 2009 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 19 #include <linux/sched.h> 20 #include <linux/pagemap.h> 21 #include <linux/writeback.h> 22 #include <linux/blkdev.h> 23 #include <linux/rbtree.h> 24 #include <linux/slab.h> 25 #include "ctree.h" 26 #include "disk-io.h" 27 #include "transaction.h" 28 #include "volumes.h" 29 #include "locking.h" 30 #include "btrfs_inode.h" 31 #include "async-thread.h" 32 #include "free-space-cache.h" 33 34 /* 35 * backref_node, mapping_node and tree_block start with this 36 */ 37 struct tree_entry { 38 struct rb_node rb_node; 39 u64 bytenr; 40 }; 41 42 /* 43 * present a tree block in the backref cache 44 */ 45 struct backref_node { 46 struct rb_node rb_node; 47 u64 bytenr; 48 49 u64 new_bytenr; 50 /* objectid of tree block owner, can be not uptodate */ 51 u64 owner; 52 /* link to pending, changed or detached list */ 53 struct list_head list; 54 /* list of upper level blocks reference this block */ 55 struct list_head upper; 56 /* list of child blocks in the cache */ 57 struct list_head lower; 58 /* NULL if this node is not tree root */ 59 struct btrfs_root *root; 60 /* extent buffer got by COW the block */ 61 struct extent_buffer *eb; 62 /* level of tree block */ 63 unsigned int level:8; 64 /* is the block in non-reference counted tree */ 65 unsigned int cowonly:1; 66 /* 1 if no child node in the cache */ 67 unsigned int lowest:1; 68 /* is the extent buffer locked */ 69 unsigned int locked:1; 70 /* has the block been processed */ 71 unsigned int processed:1; 72 /* have backrefs of this block been checked */ 73 unsigned int checked:1; 74 /* 75 * 1 if corresponding block has been cowed but some upper 76 * level block pointers may not point to the new location 77 */ 78 unsigned int pending:1; 79 /* 80 * 1 if the backref node isn't connected to any other 81 * backref node. 82 */ 83 unsigned int detached:1; 84 }; 85 86 /* 87 * present a block pointer in the backref cache 88 */ 89 struct backref_edge { 90 struct list_head list[2]; 91 struct backref_node *node[2]; 92 }; 93 94 #define LOWER 0 95 #define UPPER 1 96 97 struct backref_cache { 98 /* red black tree of all backref nodes in the cache */ 99 struct rb_root rb_root; 100 /* for passing backref nodes to btrfs_reloc_cow_block */ 101 struct backref_node *path[BTRFS_MAX_LEVEL]; 102 /* 103 * list of blocks that have been cowed but some block 104 * pointers in upper level blocks may not reflect the 105 * new location 106 */ 107 struct list_head pending[BTRFS_MAX_LEVEL]; 108 /* list of backref nodes with no child node */ 109 struct list_head leaves; 110 /* list of blocks that have been cowed in current transaction */ 111 struct list_head changed; 112 /* list of detached backref node. */ 113 struct list_head detached; 114 115 u64 last_trans; 116 117 int nr_nodes; 118 int nr_edges; 119 }; 120 121 /* 122 * map address of tree root to tree 123 */ 124 struct mapping_node { 125 struct rb_node rb_node; 126 u64 bytenr; 127 void *data; 128 }; 129 130 struct mapping_tree { 131 struct rb_root rb_root; 132 spinlock_t lock; 133 }; 134 135 /* 136 * present a tree block to process 137 */ 138 struct tree_block { 139 struct rb_node rb_node; 140 u64 bytenr; 141 struct btrfs_key key; 142 unsigned int level:8; 143 unsigned int key_ready:1; 144 }; 145 146 #define MAX_EXTENTS 128 147 148 struct file_extent_cluster { 149 u64 start; 150 u64 end; 151 u64 boundary[MAX_EXTENTS]; 152 unsigned int nr; 153 }; 154 155 struct reloc_control { 156 /* block group to relocate */ 157 struct btrfs_block_group_cache *block_group; 158 /* extent tree */ 159 struct btrfs_root *extent_root; 160 /* inode for moving data */ 161 struct inode *data_inode; 162 163 struct btrfs_block_rsv *block_rsv; 164 165 struct backref_cache backref_cache; 166 167 struct file_extent_cluster cluster; 168 /* tree blocks have been processed */ 169 struct extent_io_tree processed_blocks; 170 /* map start of tree root to corresponding reloc tree */ 171 struct mapping_tree reloc_root_tree; 172 /* list of reloc trees */ 173 struct list_head reloc_roots; 174 /* size of metadata reservation for merging reloc trees */ 175 u64 merging_rsv_size; 176 /* size of relocated tree nodes */ 177 u64 nodes_relocated; 178 179 u64 search_start; 180 u64 extents_found; 181 182 unsigned int stage:8; 183 unsigned int create_reloc_tree:1; 184 unsigned int merge_reloc_tree:1; 185 unsigned int found_file_extent:1; 186 unsigned int commit_transaction:1; 187 }; 188 189 /* stages of data relocation */ 190 #define MOVE_DATA_EXTENTS 0 191 #define UPDATE_DATA_PTRS 1 192 193 static void remove_backref_node(struct backref_cache *cache, 194 struct backref_node *node); 195 static void __mark_block_processed(struct reloc_control *rc, 196 struct backref_node *node); 197 198 static void mapping_tree_init(struct mapping_tree *tree) 199 { 200 tree->rb_root = RB_ROOT; 201 spin_lock_init(&tree->lock); 202 } 203 204 static void backref_cache_init(struct backref_cache *cache) 205 { 206 int i; 207 cache->rb_root = RB_ROOT; 208 for (i = 0; i < BTRFS_MAX_LEVEL; i++) 209 INIT_LIST_HEAD(&cache->pending[i]); 210 INIT_LIST_HEAD(&cache->changed); 211 INIT_LIST_HEAD(&cache->detached); 212 INIT_LIST_HEAD(&cache->leaves); 213 } 214 215 static void backref_cache_cleanup(struct backref_cache *cache) 216 { 217 struct backref_node *node; 218 int i; 219 220 while (!list_empty(&cache->detached)) { 221 node = list_entry(cache->detached.next, 222 struct backref_node, list); 223 remove_backref_node(cache, node); 224 } 225 226 while (!list_empty(&cache->leaves)) { 227 node = list_entry(cache->leaves.next, 228 struct backref_node, lower); 229 remove_backref_node(cache, node); 230 } 231 232 cache->last_trans = 0; 233 234 for (i = 0; i < BTRFS_MAX_LEVEL; i++) 235 BUG_ON(!list_empty(&cache->pending[i])); 236 BUG_ON(!list_empty(&cache->changed)); 237 BUG_ON(!list_empty(&cache->detached)); 238 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root)); 239 BUG_ON(cache->nr_nodes); 240 BUG_ON(cache->nr_edges); 241 } 242 243 static struct backref_node *alloc_backref_node(struct backref_cache *cache) 244 { 245 struct backref_node *node; 246 247 node = kzalloc(sizeof(*node), GFP_NOFS); 248 if (node) { 249 INIT_LIST_HEAD(&node->list); 250 INIT_LIST_HEAD(&node->upper); 251 INIT_LIST_HEAD(&node->lower); 252 RB_CLEAR_NODE(&node->rb_node); 253 cache->nr_nodes++; 254 } 255 return node; 256 } 257 258 static void free_backref_node(struct backref_cache *cache, 259 struct backref_node *node) 260 { 261 if (node) { 262 cache->nr_nodes--; 263 kfree(node); 264 } 265 } 266 267 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache) 268 { 269 struct backref_edge *edge; 270 271 edge = kzalloc(sizeof(*edge), GFP_NOFS); 272 if (edge) 273 cache->nr_edges++; 274 return edge; 275 } 276 277 static void free_backref_edge(struct backref_cache *cache, 278 struct backref_edge *edge) 279 { 280 if (edge) { 281 cache->nr_edges--; 282 kfree(edge); 283 } 284 } 285 286 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr, 287 struct rb_node *node) 288 { 289 struct rb_node **p = &root->rb_node; 290 struct rb_node *parent = NULL; 291 struct tree_entry *entry; 292 293 while (*p) { 294 parent = *p; 295 entry = rb_entry(parent, struct tree_entry, rb_node); 296 297 if (bytenr < entry->bytenr) 298 p = &(*p)->rb_left; 299 else if (bytenr > entry->bytenr) 300 p = &(*p)->rb_right; 301 else 302 return parent; 303 } 304 305 rb_link_node(node, parent, p); 306 rb_insert_color(node, root); 307 return NULL; 308 } 309 310 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr) 311 { 312 struct rb_node *n = root->rb_node; 313 struct tree_entry *entry; 314 315 while (n) { 316 entry = rb_entry(n, struct tree_entry, rb_node); 317 318 if (bytenr < entry->bytenr) 319 n = n->rb_left; 320 else if (bytenr > entry->bytenr) 321 n = n->rb_right; 322 else 323 return n; 324 } 325 return NULL; 326 } 327 328 /* 329 * walk up backref nodes until reach node presents tree root 330 */ 331 static struct backref_node *walk_up_backref(struct backref_node *node, 332 struct backref_edge *edges[], 333 int *index) 334 { 335 struct backref_edge *edge; 336 int idx = *index; 337 338 while (!list_empty(&node->upper)) { 339 edge = list_entry(node->upper.next, 340 struct backref_edge, list[LOWER]); 341 edges[idx++] = edge; 342 node = edge->node[UPPER]; 343 } 344 BUG_ON(node->detached); 345 *index = idx; 346 return node; 347 } 348 349 /* 350 * walk down backref nodes to find start of next reference path 351 */ 352 static struct backref_node *walk_down_backref(struct backref_edge *edges[], 353 int *index) 354 { 355 struct backref_edge *edge; 356 struct backref_node *lower; 357 int idx = *index; 358 359 while (idx > 0) { 360 edge = edges[idx - 1]; 361 lower = edge->node[LOWER]; 362 if (list_is_last(&edge->list[LOWER], &lower->upper)) { 363 idx--; 364 continue; 365 } 366 edge = list_entry(edge->list[LOWER].next, 367 struct backref_edge, list[LOWER]); 368 edges[idx - 1] = edge; 369 *index = idx; 370 return edge->node[UPPER]; 371 } 372 *index = 0; 373 return NULL; 374 } 375 376 static void unlock_node_buffer(struct backref_node *node) 377 { 378 if (node->locked) { 379 btrfs_tree_unlock(node->eb); 380 node->locked = 0; 381 } 382 } 383 384 static void drop_node_buffer(struct backref_node *node) 385 { 386 if (node->eb) { 387 unlock_node_buffer(node); 388 free_extent_buffer(node->eb); 389 node->eb = NULL; 390 } 391 } 392 393 static void drop_backref_node(struct backref_cache *tree, 394 struct backref_node *node) 395 { 396 BUG_ON(!list_empty(&node->upper)); 397 398 drop_node_buffer(node); 399 list_del(&node->list); 400 list_del(&node->lower); 401 if (!RB_EMPTY_NODE(&node->rb_node)) 402 rb_erase(&node->rb_node, &tree->rb_root); 403 free_backref_node(tree, node); 404 } 405 406 /* 407 * remove a backref node from the backref cache 408 */ 409 static void remove_backref_node(struct backref_cache *cache, 410 struct backref_node *node) 411 { 412 struct backref_node *upper; 413 struct backref_edge *edge; 414 415 if (!node) 416 return; 417 418 BUG_ON(!node->lowest && !node->detached); 419 while (!list_empty(&node->upper)) { 420 edge = list_entry(node->upper.next, struct backref_edge, 421 list[LOWER]); 422 upper = edge->node[UPPER]; 423 list_del(&edge->list[LOWER]); 424 list_del(&edge->list[UPPER]); 425 free_backref_edge(cache, edge); 426 427 if (RB_EMPTY_NODE(&upper->rb_node)) { 428 BUG_ON(!list_empty(&node->upper)); 429 drop_backref_node(cache, node); 430 node = upper; 431 node->lowest = 1; 432 continue; 433 } 434 /* 435 * add the node to leaf node list if no other 436 * child block cached. 437 */ 438 if (list_empty(&upper->lower)) { 439 list_add_tail(&upper->lower, &cache->leaves); 440 upper->lowest = 1; 441 } 442 } 443 444 drop_backref_node(cache, node); 445 } 446 447 static void update_backref_node(struct backref_cache *cache, 448 struct backref_node *node, u64 bytenr) 449 { 450 struct rb_node *rb_node; 451 rb_erase(&node->rb_node, &cache->rb_root); 452 node->bytenr = bytenr; 453 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node); 454 BUG_ON(rb_node); 455 } 456 457 /* 458 * update backref cache after a transaction commit 459 */ 460 static int update_backref_cache(struct btrfs_trans_handle *trans, 461 struct backref_cache *cache) 462 { 463 struct backref_node *node; 464 int level = 0; 465 466 if (cache->last_trans == 0) { 467 cache->last_trans = trans->transid; 468 return 0; 469 } 470 471 if (cache->last_trans == trans->transid) 472 return 0; 473 474 /* 475 * detached nodes are used to avoid unnecessary backref 476 * lookup. transaction commit changes the extent tree. 477 * so the detached nodes are no longer useful. 478 */ 479 while (!list_empty(&cache->detached)) { 480 node = list_entry(cache->detached.next, 481 struct backref_node, list); 482 remove_backref_node(cache, node); 483 } 484 485 while (!list_empty(&cache->changed)) { 486 node = list_entry(cache->changed.next, 487 struct backref_node, list); 488 list_del_init(&node->list); 489 BUG_ON(node->pending); 490 update_backref_node(cache, node, node->new_bytenr); 491 } 492 493 /* 494 * some nodes can be left in the pending list if there were 495 * errors during processing the pending nodes. 496 */ 497 for (level = 0; level < BTRFS_MAX_LEVEL; level++) { 498 list_for_each_entry(node, &cache->pending[level], list) { 499 BUG_ON(!node->pending); 500 if (node->bytenr == node->new_bytenr) 501 continue; 502 update_backref_node(cache, node, node->new_bytenr); 503 } 504 } 505 506 cache->last_trans = 0; 507 return 1; 508 } 509 510 static int should_ignore_root(struct btrfs_root *root) 511 { 512 struct btrfs_root *reloc_root; 513 514 if (!root->ref_cows) 515 return 0; 516 517 reloc_root = root->reloc_root; 518 if (!reloc_root) 519 return 0; 520 521 if (btrfs_root_last_snapshot(&reloc_root->root_item) == 522 root->fs_info->running_transaction->transid - 1) 523 return 0; 524 /* 525 * if there is reloc tree and it was created in previous 526 * transaction backref lookup can find the reloc tree, 527 * so backref node for the fs tree root is useless for 528 * relocation. 529 */ 530 return 1; 531 } 532 533 /* 534 * find reloc tree by address of tree root 535 */ 536 static struct btrfs_root *find_reloc_root(struct reloc_control *rc, 537 u64 bytenr) 538 { 539 struct rb_node *rb_node; 540 struct mapping_node *node; 541 struct btrfs_root *root = NULL; 542 543 spin_lock(&rc->reloc_root_tree.lock); 544 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr); 545 if (rb_node) { 546 node = rb_entry(rb_node, struct mapping_node, rb_node); 547 root = (struct btrfs_root *)node->data; 548 } 549 spin_unlock(&rc->reloc_root_tree.lock); 550 return root; 551 } 552 553 static int is_cowonly_root(u64 root_objectid) 554 { 555 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID || 556 root_objectid == BTRFS_EXTENT_TREE_OBJECTID || 557 root_objectid == BTRFS_CHUNK_TREE_OBJECTID || 558 root_objectid == BTRFS_DEV_TREE_OBJECTID || 559 root_objectid == BTRFS_TREE_LOG_OBJECTID || 560 root_objectid == BTRFS_CSUM_TREE_OBJECTID) 561 return 1; 562 return 0; 563 } 564 565 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info, 566 u64 root_objectid) 567 { 568 struct btrfs_key key; 569 570 key.objectid = root_objectid; 571 key.type = BTRFS_ROOT_ITEM_KEY; 572 if (is_cowonly_root(root_objectid)) 573 key.offset = 0; 574 else 575 key.offset = (u64)-1; 576 577 return btrfs_read_fs_root_no_name(fs_info, &key); 578 } 579 580 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 581 static noinline_for_stack 582 struct btrfs_root *find_tree_root(struct reloc_control *rc, 583 struct extent_buffer *leaf, 584 struct btrfs_extent_ref_v0 *ref0) 585 { 586 struct btrfs_root *root; 587 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0); 588 u64 generation = btrfs_ref_generation_v0(leaf, ref0); 589 590 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID); 591 592 root = read_fs_root(rc->extent_root->fs_info, root_objectid); 593 BUG_ON(IS_ERR(root)); 594 595 if (root->ref_cows && 596 generation != btrfs_root_generation(&root->root_item)) 597 return NULL; 598 599 return root; 600 } 601 #endif 602 603 static noinline_for_stack 604 int find_inline_backref(struct extent_buffer *leaf, int slot, 605 unsigned long *ptr, unsigned long *end) 606 { 607 struct btrfs_extent_item *ei; 608 struct btrfs_tree_block_info *bi; 609 u32 item_size; 610 611 item_size = btrfs_item_size_nr(leaf, slot); 612 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 613 if (item_size < sizeof(*ei)) { 614 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0)); 615 return 1; 616 } 617 #endif 618 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); 619 WARN_ON(!(btrfs_extent_flags(leaf, ei) & 620 BTRFS_EXTENT_FLAG_TREE_BLOCK)); 621 622 if (item_size <= sizeof(*ei) + sizeof(*bi)) { 623 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi)); 624 return 1; 625 } 626 627 bi = (struct btrfs_tree_block_info *)(ei + 1); 628 *ptr = (unsigned long)(bi + 1); 629 *end = (unsigned long)ei + item_size; 630 return 0; 631 } 632 633 /* 634 * build backref tree for a given tree block. root of the backref tree 635 * corresponds the tree block, leaves of the backref tree correspond 636 * roots of b-trees that reference the tree block. 637 * 638 * the basic idea of this function is check backrefs of a given block 639 * to find upper level blocks that refernece the block, and then check 640 * bakcrefs of these upper level blocks recursively. the recursion stop 641 * when tree root is reached or backrefs for the block is cached. 642 * 643 * NOTE: if we find backrefs for a block are cached, we know backrefs 644 * for all upper level blocks that directly/indirectly reference the 645 * block are also cached. 646 */ 647 static noinline_for_stack 648 struct backref_node *build_backref_tree(struct reloc_control *rc, 649 struct btrfs_key *node_key, 650 int level, u64 bytenr) 651 { 652 struct backref_cache *cache = &rc->backref_cache; 653 struct btrfs_path *path1; 654 struct btrfs_path *path2; 655 struct extent_buffer *eb; 656 struct btrfs_root *root; 657 struct backref_node *cur; 658 struct backref_node *upper; 659 struct backref_node *lower; 660 struct backref_node *node = NULL; 661 struct backref_node *exist = NULL; 662 struct backref_edge *edge; 663 struct rb_node *rb_node; 664 struct btrfs_key key; 665 unsigned long end; 666 unsigned long ptr; 667 LIST_HEAD(list); 668 LIST_HEAD(useless); 669 int cowonly; 670 int ret; 671 int err = 0; 672 673 path1 = btrfs_alloc_path(); 674 path2 = btrfs_alloc_path(); 675 if (!path1 || !path2) { 676 err = -ENOMEM; 677 goto out; 678 } 679 680 node = alloc_backref_node(cache); 681 if (!node) { 682 err = -ENOMEM; 683 goto out; 684 } 685 686 node->bytenr = bytenr; 687 node->level = level; 688 node->lowest = 1; 689 cur = node; 690 again: 691 end = 0; 692 ptr = 0; 693 key.objectid = cur->bytenr; 694 key.type = BTRFS_EXTENT_ITEM_KEY; 695 key.offset = (u64)-1; 696 697 path1->search_commit_root = 1; 698 path1->skip_locking = 1; 699 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1, 700 0, 0); 701 if (ret < 0) { 702 err = ret; 703 goto out; 704 } 705 BUG_ON(!ret || !path1->slots[0]); 706 707 path1->slots[0]--; 708 709 WARN_ON(cur->checked); 710 if (!list_empty(&cur->upper)) { 711 /* 712 * the backref was added previously when processsing 713 * backref of type BTRFS_TREE_BLOCK_REF_KEY 714 */ 715 BUG_ON(!list_is_singular(&cur->upper)); 716 edge = list_entry(cur->upper.next, struct backref_edge, 717 list[LOWER]); 718 BUG_ON(!list_empty(&edge->list[UPPER])); 719 exist = edge->node[UPPER]; 720 /* 721 * add the upper level block to pending list if we need 722 * check its backrefs 723 */ 724 if (!exist->checked) 725 list_add_tail(&edge->list[UPPER], &list); 726 } else { 727 exist = NULL; 728 } 729 730 while (1) { 731 cond_resched(); 732 eb = path1->nodes[0]; 733 734 if (ptr >= end) { 735 if (path1->slots[0] >= btrfs_header_nritems(eb)) { 736 ret = btrfs_next_leaf(rc->extent_root, path1); 737 if (ret < 0) { 738 err = ret; 739 goto out; 740 } 741 if (ret > 0) 742 break; 743 eb = path1->nodes[0]; 744 } 745 746 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]); 747 if (key.objectid != cur->bytenr) { 748 WARN_ON(exist); 749 break; 750 } 751 752 if (key.type == BTRFS_EXTENT_ITEM_KEY) { 753 ret = find_inline_backref(eb, path1->slots[0], 754 &ptr, &end); 755 if (ret) 756 goto next; 757 } 758 } 759 760 if (ptr < end) { 761 /* update key for inline back ref */ 762 struct btrfs_extent_inline_ref *iref; 763 iref = (struct btrfs_extent_inline_ref *)ptr; 764 key.type = btrfs_extent_inline_ref_type(eb, iref); 765 key.offset = btrfs_extent_inline_ref_offset(eb, iref); 766 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY && 767 key.type != BTRFS_SHARED_BLOCK_REF_KEY); 768 } 769 770 if (exist && 771 ((key.type == BTRFS_TREE_BLOCK_REF_KEY && 772 exist->owner == key.offset) || 773 (key.type == BTRFS_SHARED_BLOCK_REF_KEY && 774 exist->bytenr == key.offset))) { 775 exist = NULL; 776 goto next; 777 } 778 779 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 780 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY || 781 key.type == BTRFS_EXTENT_REF_V0_KEY) { 782 if (key.type == BTRFS_EXTENT_REF_V0_KEY) { 783 struct btrfs_extent_ref_v0 *ref0; 784 ref0 = btrfs_item_ptr(eb, path1->slots[0], 785 struct btrfs_extent_ref_v0); 786 if (key.objectid == key.offset) { 787 root = find_tree_root(rc, eb, ref0); 788 if (root && !should_ignore_root(root)) 789 cur->root = root; 790 else 791 list_add(&cur->list, &useless); 792 break; 793 } 794 if (is_cowonly_root(btrfs_ref_root_v0(eb, 795 ref0))) 796 cur->cowonly = 1; 797 } 798 #else 799 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY); 800 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) { 801 #endif 802 if (key.objectid == key.offset) { 803 /* 804 * only root blocks of reloc trees use 805 * backref of this type. 806 */ 807 root = find_reloc_root(rc, cur->bytenr); 808 BUG_ON(!root); 809 cur->root = root; 810 break; 811 } 812 813 edge = alloc_backref_edge(cache); 814 if (!edge) { 815 err = -ENOMEM; 816 goto out; 817 } 818 rb_node = tree_search(&cache->rb_root, key.offset); 819 if (!rb_node) { 820 upper = alloc_backref_node(cache); 821 if (!upper) { 822 free_backref_edge(cache, edge); 823 err = -ENOMEM; 824 goto out; 825 } 826 upper->bytenr = key.offset; 827 upper->level = cur->level + 1; 828 /* 829 * backrefs for the upper level block isn't 830 * cached, add the block to pending list 831 */ 832 list_add_tail(&edge->list[UPPER], &list); 833 } else { 834 upper = rb_entry(rb_node, struct backref_node, 835 rb_node); 836 BUG_ON(!upper->checked); 837 INIT_LIST_HEAD(&edge->list[UPPER]); 838 } 839 list_add_tail(&edge->list[LOWER], &cur->upper); 840 edge->node[LOWER] = cur; 841 edge->node[UPPER] = upper; 842 843 goto next; 844 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) { 845 goto next; 846 } 847 848 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */ 849 root = read_fs_root(rc->extent_root->fs_info, key.offset); 850 if (IS_ERR(root)) { 851 err = PTR_ERR(root); 852 goto out; 853 } 854 855 if (!root->ref_cows) 856 cur->cowonly = 1; 857 858 if (btrfs_root_level(&root->root_item) == cur->level) { 859 /* tree root */ 860 BUG_ON(btrfs_root_bytenr(&root->root_item) != 861 cur->bytenr); 862 if (should_ignore_root(root)) 863 list_add(&cur->list, &useless); 864 else 865 cur->root = root; 866 break; 867 } 868 869 level = cur->level + 1; 870 871 /* 872 * searching the tree to find upper level blocks 873 * reference the block. 874 */ 875 path2->search_commit_root = 1; 876 path2->skip_locking = 1; 877 path2->lowest_level = level; 878 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0); 879 path2->lowest_level = 0; 880 if (ret < 0) { 881 err = ret; 882 goto out; 883 } 884 if (ret > 0 && path2->slots[level] > 0) 885 path2->slots[level]--; 886 887 eb = path2->nodes[level]; 888 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) != 889 cur->bytenr); 890 891 lower = cur; 892 for (; level < BTRFS_MAX_LEVEL; level++) { 893 if (!path2->nodes[level]) { 894 BUG_ON(btrfs_root_bytenr(&root->root_item) != 895 lower->bytenr); 896 if (should_ignore_root(root)) 897 list_add(&lower->list, &useless); 898 else 899 lower->root = root; 900 break; 901 } 902 903 edge = alloc_backref_edge(cache); 904 if (!edge) { 905 err = -ENOMEM; 906 goto out; 907 } 908 909 eb = path2->nodes[level]; 910 rb_node = tree_search(&cache->rb_root, eb->start); 911 if (!rb_node) { 912 upper = alloc_backref_node(cache); 913 if (!upper) { 914 free_backref_edge(cache, edge); 915 err = -ENOMEM; 916 goto out; 917 } 918 upper->bytenr = eb->start; 919 upper->owner = btrfs_header_owner(eb); 920 upper->level = lower->level + 1; 921 if (!root->ref_cows) 922 upper->cowonly = 1; 923 924 /* 925 * if we know the block isn't shared 926 * we can void checking its backrefs. 927 */ 928 if (btrfs_block_can_be_shared(root, eb)) 929 upper->checked = 0; 930 else 931 upper->checked = 1; 932 933 /* 934 * add the block to pending list if we 935 * need check its backrefs. only block 936 * at 'cur->level + 1' is added to the 937 * tail of pending list. this guarantees 938 * we check backrefs from lower level 939 * blocks to upper level blocks. 940 */ 941 if (!upper->checked && 942 level == cur->level + 1) { 943 list_add_tail(&edge->list[UPPER], 944 &list); 945 } else 946 INIT_LIST_HEAD(&edge->list[UPPER]); 947 } else { 948 upper = rb_entry(rb_node, struct backref_node, 949 rb_node); 950 BUG_ON(!upper->checked); 951 INIT_LIST_HEAD(&edge->list[UPPER]); 952 if (!upper->owner) 953 upper->owner = btrfs_header_owner(eb); 954 } 955 list_add_tail(&edge->list[LOWER], &lower->upper); 956 edge->node[LOWER] = lower; 957 edge->node[UPPER] = upper; 958 959 if (rb_node) 960 break; 961 lower = upper; 962 upper = NULL; 963 } 964 btrfs_release_path(root, path2); 965 next: 966 if (ptr < end) { 967 ptr += btrfs_extent_inline_ref_size(key.type); 968 if (ptr >= end) { 969 WARN_ON(ptr > end); 970 ptr = 0; 971 end = 0; 972 } 973 } 974 if (ptr >= end) 975 path1->slots[0]++; 976 } 977 btrfs_release_path(rc->extent_root, path1); 978 979 cur->checked = 1; 980 WARN_ON(exist); 981 982 /* the pending list isn't empty, take the first block to process */ 983 if (!list_empty(&list)) { 984 edge = list_entry(list.next, struct backref_edge, list[UPPER]); 985 list_del_init(&edge->list[UPPER]); 986 cur = edge->node[UPPER]; 987 goto again; 988 } 989 990 /* 991 * everything goes well, connect backref nodes and insert backref nodes 992 * into the cache. 993 */ 994 BUG_ON(!node->checked); 995 cowonly = node->cowonly; 996 if (!cowonly) { 997 rb_node = tree_insert(&cache->rb_root, node->bytenr, 998 &node->rb_node); 999 BUG_ON(rb_node); 1000 list_add_tail(&node->lower, &cache->leaves); 1001 } 1002 1003 list_for_each_entry(edge, &node->upper, list[LOWER]) 1004 list_add_tail(&edge->list[UPPER], &list); 1005 1006 while (!list_empty(&list)) { 1007 edge = list_entry(list.next, struct backref_edge, list[UPPER]); 1008 list_del_init(&edge->list[UPPER]); 1009 upper = edge->node[UPPER]; 1010 if (upper->detached) { 1011 list_del(&edge->list[LOWER]); 1012 lower = edge->node[LOWER]; 1013 free_backref_edge(cache, edge); 1014 if (list_empty(&lower->upper)) 1015 list_add(&lower->list, &useless); 1016 continue; 1017 } 1018 1019 if (!RB_EMPTY_NODE(&upper->rb_node)) { 1020 if (upper->lowest) { 1021 list_del_init(&upper->lower); 1022 upper->lowest = 0; 1023 } 1024 1025 list_add_tail(&edge->list[UPPER], &upper->lower); 1026 continue; 1027 } 1028 1029 BUG_ON(!upper->checked); 1030 BUG_ON(cowonly != upper->cowonly); 1031 if (!cowonly) { 1032 rb_node = tree_insert(&cache->rb_root, upper->bytenr, 1033 &upper->rb_node); 1034 BUG_ON(rb_node); 1035 } 1036 1037 list_add_tail(&edge->list[UPPER], &upper->lower); 1038 1039 list_for_each_entry(edge, &upper->upper, list[LOWER]) 1040 list_add_tail(&edge->list[UPPER], &list); 1041 } 1042 /* 1043 * process useless backref nodes. backref nodes for tree leaves 1044 * are deleted from the cache. backref nodes for upper level 1045 * tree blocks are left in the cache to avoid unnecessary backref 1046 * lookup. 1047 */ 1048 while (!list_empty(&useless)) { 1049 upper = list_entry(useless.next, struct backref_node, list); 1050 list_del_init(&upper->list); 1051 BUG_ON(!list_empty(&upper->upper)); 1052 if (upper == node) 1053 node = NULL; 1054 if (upper->lowest) { 1055 list_del_init(&upper->lower); 1056 upper->lowest = 0; 1057 } 1058 while (!list_empty(&upper->lower)) { 1059 edge = list_entry(upper->lower.next, 1060 struct backref_edge, list[UPPER]); 1061 list_del(&edge->list[UPPER]); 1062 list_del(&edge->list[LOWER]); 1063 lower = edge->node[LOWER]; 1064 free_backref_edge(cache, edge); 1065 1066 if (list_empty(&lower->upper)) 1067 list_add(&lower->list, &useless); 1068 } 1069 __mark_block_processed(rc, upper); 1070 if (upper->level > 0) { 1071 list_add(&upper->list, &cache->detached); 1072 upper->detached = 1; 1073 } else { 1074 rb_erase(&upper->rb_node, &cache->rb_root); 1075 free_backref_node(cache, upper); 1076 } 1077 } 1078 out: 1079 btrfs_free_path(path1); 1080 btrfs_free_path(path2); 1081 if (err) { 1082 while (!list_empty(&useless)) { 1083 lower = list_entry(useless.next, 1084 struct backref_node, upper); 1085 list_del_init(&lower->upper); 1086 } 1087 upper = node; 1088 INIT_LIST_HEAD(&list); 1089 while (upper) { 1090 if (RB_EMPTY_NODE(&upper->rb_node)) { 1091 list_splice_tail(&upper->upper, &list); 1092 free_backref_node(cache, upper); 1093 } 1094 1095 if (list_empty(&list)) 1096 break; 1097 1098 edge = list_entry(list.next, struct backref_edge, 1099 list[LOWER]); 1100 list_del(&edge->list[LOWER]); 1101 upper = edge->node[UPPER]; 1102 free_backref_edge(cache, edge); 1103 } 1104 return ERR_PTR(err); 1105 } 1106 BUG_ON(node && node->detached); 1107 return node; 1108 } 1109 1110 /* 1111 * helper to add backref node for the newly created snapshot. 1112 * the backref node is created by cloning backref node that 1113 * corresponds to root of source tree 1114 */ 1115 static int clone_backref_node(struct btrfs_trans_handle *trans, 1116 struct reloc_control *rc, 1117 struct btrfs_root *src, 1118 struct btrfs_root *dest) 1119 { 1120 struct btrfs_root *reloc_root = src->reloc_root; 1121 struct backref_cache *cache = &rc->backref_cache; 1122 struct backref_node *node = NULL; 1123 struct backref_node *new_node; 1124 struct backref_edge *edge; 1125 struct backref_edge *new_edge; 1126 struct rb_node *rb_node; 1127 1128 if (cache->last_trans > 0) 1129 update_backref_cache(trans, cache); 1130 1131 rb_node = tree_search(&cache->rb_root, src->commit_root->start); 1132 if (rb_node) { 1133 node = rb_entry(rb_node, struct backref_node, rb_node); 1134 if (node->detached) 1135 node = NULL; 1136 else 1137 BUG_ON(node->new_bytenr != reloc_root->node->start); 1138 } 1139 1140 if (!node) { 1141 rb_node = tree_search(&cache->rb_root, 1142 reloc_root->commit_root->start); 1143 if (rb_node) { 1144 node = rb_entry(rb_node, struct backref_node, 1145 rb_node); 1146 BUG_ON(node->detached); 1147 } 1148 } 1149 1150 if (!node) 1151 return 0; 1152 1153 new_node = alloc_backref_node(cache); 1154 if (!new_node) 1155 return -ENOMEM; 1156 1157 new_node->bytenr = dest->node->start; 1158 new_node->level = node->level; 1159 new_node->lowest = node->lowest; 1160 new_node->root = dest; 1161 1162 if (!node->lowest) { 1163 list_for_each_entry(edge, &node->lower, list[UPPER]) { 1164 new_edge = alloc_backref_edge(cache); 1165 if (!new_edge) 1166 goto fail; 1167 1168 new_edge->node[UPPER] = new_node; 1169 new_edge->node[LOWER] = edge->node[LOWER]; 1170 list_add_tail(&new_edge->list[UPPER], 1171 &new_node->lower); 1172 } 1173 } 1174 1175 rb_node = tree_insert(&cache->rb_root, new_node->bytenr, 1176 &new_node->rb_node); 1177 BUG_ON(rb_node); 1178 1179 if (!new_node->lowest) { 1180 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) { 1181 list_add_tail(&new_edge->list[LOWER], 1182 &new_edge->node[LOWER]->upper); 1183 } 1184 } 1185 return 0; 1186 fail: 1187 while (!list_empty(&new_node->lower)) { 1188 new_edge = list_entry(new_node->lower.next, 1189 struct backref_edge, list[UPPER]); 1190 list_del(&new_edge->list[UPPER]); 1191 free_backref_edge(cache, new_edge); 1192 } 1193 free_backref_node(cache, new_node); 1194 return -ENOMEM; 1195 } 1196 1197 /* 1198 * helper to add 'address of tree root -> reloc tree' mapping 1199 */ 1200 static int __add_reloc_root(struct btrfs_root *root) 1201 { 1202 struct rb_node *rb_node; 1203 struct mapping_node *node; 1204 struct reloc_control *rc = root->fs_info->reloc_ctl; 1205 1206 node = kmalloc(sizeof(*node), GFP_NOFS); 1207 BUG_ON(!node); 1208 1209 node->bytenr = root->node->start; 1210 node->data = root; 1211 1212 spin_lock(&rc->reloc_root_tree.lock); 1213 rb_node = tree_insert(&rc->reloc_root_tree.rb_root, 1214 node->bytenr, &node->rb_node); 1215 spin_unlock(&rc->reloc_root_tree.lock); 1216 BUG_ON(rb_node); 1217 1218 list_add_tail(&root->root_list, &rc->reloc_roots); 1219 return 0; 1220 } 1221 1222 /* 1223 * helper to update/delete the 'address of tree root -> reloc tree' 1224 * mapping 1225 */ 1226 static int __update_reloc_root(struct btrfs_root *root, int del) 1227 { 1228 struct rb_node *rb_node; 1229 struct mapping_node *node = NULL; 1230 struct reloc_control *rc = root->fs_info->reloc_ctl; 1231 1232 spin_lock(&rc->reloc_root_tree.lock); 1233 rb_node = tree_search(&rc->reloc_root_tree.rb_root, 1234 root->commit_root->start); 1235 if (rb_node) { 1236 node = rb_entry(rb_node, struct mapping_node, rb_node); 1237 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root); 1238 } 1239 spin_unlock(&rc->reloc_root_tree.lock); 1240 1241 BUG_ON((struct btrfs_root *)node->data != root); 1242 1243 if (!del) { 1244 spin_lock(&rc->reloc_root_tree.lock); 1245 node->bytenr = root->node->start; 1246 rb_node = tree_insert(&rc->reloc_root_tree.rb_root, 1247 node->bytenr, &node->rb_node); 1248 spin_unlock(&rc->reloc_root_tree.lock); 1249 BUG_ON(rb_node); 1250 } else { 1251 list_del_init(&root->root_list); 1252 kfree(node); 1253 } 1254 return 0; 1255 } 1256 1257 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans, 1258 struct btrfs_root *root, u64 objectid) 1259 { 1260 struct btrfs_root *reloc_root; 1261 struct extent_buffer *eb; 1262 struct btrfs_root_item *root_item; 1263 struct btrfs_key root_key; 1264 int ret; 1265 1266 root_item = kmalloc(sizeof(*root_item), GFP_NOFS); 1267 BUG_ON(!root_item); 1268 1269 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID; 1270 root_key.type = BTRFS_ROOT_ITEM_KEY; 1271 root_key.offset = objectid; 1272 1273 if (root->root_key.objectid == objectid) { 1274 /* called by btrfs_init_reloc_root */ 1275 ret = btrfs_copy_root(trans, root, root->commit_root, &eb, 1276 BTRFS_TREE_RELOC_OBJECTID); 1277 BUG_ON(ret); 1278 1279 btrfs_set_root_last_snapshot(&root->root_item, 1280 trans->transid - 1); 1281 } else { 1282 /* 1283 * called by btrfs_reloc_post_snapshot_hook. 1284 * the source tree is a reloc tree, all tree blocks 1285 * modified after it was created have RELOC flag 1286 * set in their headers. so it's OK to not update 1287 * the 'last_snapshot'. 1288 */ 1289 ret = btrfs_copy_root(trans, root, root->node, &eb, 1290 BTRFS_TREE_RELOC_OBJECTID); 1291 BUG_ON(ret); 1292 } 1293 1294 memcpy(root_item, &root->root_item, sizeof(*root_item)); 1295 btrfs_set_root_bytenr(root_item, eb->start); 1296 btrfs_set_root_level(root_item, btrfs_header_level(eb)); 1297 btrfs_set_root_generation(root_item, trans->transid); 1298 1299 if (root->root_key.objectid == objectid) { 1300 btrfs_set_root_refs(root_item, 0); 1301 memset(&root_item->drop_progress, 0, 1302 sizeof(struct btrfs_disk_key)); 1303 root_item->drop_level = 0; 1304 } 1305 1306 btrfs_tree_unlock(eb); 1307 free_extent_buffer(eb); 1308 1309 ret = btrfs_insert_root(trans, root->fs_info->tree_root, 1310 &root_key, root_item); 1311 BUG_ON(ret); 1312 kfree(root_item); 1313 1314 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root, 1315 &root_key); 1316 BUG_ON(IS_ERR(reloc_root)); 1317 reloc_root->last_trans = trans->transid; 1318 return reloc_root; 1319 } 1320 1321 /* 1322 * create reloc tree for a given fs tree. reloc tree is just a 1323 * snapshot of the fs tree with special root objectid. 1324 */ 1325 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, 1326 struct btrfs_root *root) 1327 { 1328 struct btrfs_root *reloc_root; 1329 struct reloc_control *rc = root->fs_info->reloc_ctl; 1330 int clear_rsv = 0; 1331 1332 if (root->reloc_root) { 1333 reloc_root = root->reloc_root; 1334 reloc_root->last_trans = trans->transid; 1335 return 0; 1336 } 1337 1338 if (!rc || !rc->create_reloc_tree || 1339 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) 1340 return 0; 1341 1342 if (!trans->block_rsv) { 1343 trans->block_rsv = rc->block_rsv; 1344 clear_rsv = 1; 1345 } 1346 reloc_root = create_reloc_root(trans, root, root->root_key.objectid); 1347 if (clear_rsv) 1348 trans->block_rsv = NULL; 1349 1350 __add_reloc_root(reloc_root); 1351 root->reloc_root = reloc_root; 1352 return 0; 1353 } 1354 1355 /* 1356 * update root item of reloc tree 1357 */ 1358 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans, 1359 struct btrfs_root *root) 1360 { 1361 struct btrfs_root *reloc_root; 1362 struct btrfs_root_item *root_item; 1363 int del = 0; 1364 int ret; 1365 1366 if (!root->reloc_root) 1367 return 0; 1368 1369 reloc_root = root->reloc_root; 1370 root_item = &reloc_root->root_item; 1371 1372 if (root->fs_info->reloc_ctl->merge_reloc_tree && 1373 btrfs_root_refs(root_item) == 0) { 1374 root->reloc_root = NULL; 1375 del = 1; 1376 } 1377 1378 __update_reloc_root(reloc_root, del); 1379 1380 if (reloc_root->commit_root != reloc_root->node) { 1381 btrfs_set_root_node(root_item, reloc_root->node); 1382 free_extent_buffer(reloc_root->commit_root); 1383 reloc_root->commit_root = btrfs_root_node(reloc_root); 1384 } 1385 1386 ret = btrfs_update_root(trans, root->fs_info->tree_root, 1387 &reloc_root->root_key, root_item); 1388 BUG_ON(ret); 1389 return 0; 1390 } 1391 1392 /* 1393 * helper to find first cached inode with inode number >= objectid 1394 * in a subvolume 1395 */ 1396 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid) 1397 { 1398 struct rb_node *node; 1399 struct rb_node *prev; 1400 struct btrfs_inode *entry; 1401 struct inode *inode; 1402 1403 spin_lock(&root->inode_lock); 1404 again: 1405 node = root->inode_tree.rb_node; 1406 prev = NULL; 1407 while (node) { 1408 prev = node; 1409 entry = rb_entry(node, struct btrfs_inode, rb_node); 1410 1411 if (objectid < entry->vfs_inode.i_ino) 1412 node = node->rb_left; 1413 else if (objectid > entry->vfs_inode.i_ino) 1414 node = node->rb_right; 1415 else 1416 break; 1417 } 1418 if (!node) { 1419 while (prev) { 1420 entry = rb_entry(prev, struct btrfs_inode, rb_node); 1421 if (objectid <= entry->vfs_inode.i_ino) { 1422 node = prev; 1423 break; 1424 } 1425 prev = rb_next(prev); 1426 } 1427 } 1428 while (node) { 1429 entry = rb_entry(node, struct btrfs_inode, rb_node); 1430 inode = igrab(&entry->vfs_inode); 1431 if (inode) { 1432 spin_unlock(&root->inode_lock); 1433 return inode; 1434 } 1435 1436 objectid = entry->vfs_inode.i_ino + 1; 1437 if (cond_resched_lock(&root->inode_lock)) 1438 goto again; 1439 1440 node = rb_next(node); 1441 } 1442 spin_unlock(&root->inode_lock); 1443 return NULL; 1444 } 1445 1446 static int in_block_group(u64 bytenr, 1447 struct btrfs_block_group_cache *block_group) 1448 { 1449 if (bytenr >= block_group->key.objectid && 1450 bytenr < block_group->key.objectid + block_group->key.offset) 1451 return 1; 1452 return 0; 1453 } 1454 1455 /* 1456 * get new location of data 1457 */ 1458 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr, 1459 u64 bytenr, u64 num_bytes) 1460 { 1461 struct btrfs_root *root = BTRFS_I(reloc_inode)->root; 1462 struct btrfs_path *path; 1463 struct btrfs_file_extent_item *fi; 1464 struct extent_buffer *leaf; 1465 int ret; 1466 1467 path = btrfs_alloc_path(); 1468 if (!path) 1469 return -ENOMEM; 1470 1471 bytenr -= BTRFS_I(reloc_inode)->index_cnt; 1472 ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino, 1473 bytenr, 0); 1474 if (ret < 0) 1475 goto out; 1476 if (ret > 0) { 1477 ret = -ENOENT; 1478 goto out; 1479 } 1480 1481 leaf = path->nodes[0]; 1482 fi = btrfs_item_ptr(leaf, path->slots[0], 1483 struct btrfs_file_extent_item); 1484 1485 BUG_ON(btrfs_file_extent_offset(leaf, fi) || 1486 btrfs_file_extent_compression(leaf, fi) || 1487 btrfs_file_extent_encryption(leaf, fi) || 1488 btrfs_file_extent_other_encoding(leaf, fi)); 1489 1490 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) { 1491 ret = 1; 1492 goto out; 1493 } 1494 1495 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); 1496 ret = 0; 1497 out: 1498 btrfs_free_path(path); 1499 return ret; 1500 } 1501 1502 /* 1503 * update file extent items in the tree leaf to point to 1504 * the new locations. 1505 */ 1506 static noinline_for_stack 1507 int replace_file_extents(struct btrfs_trans_handle *trans, 1508 struct reloc_control *rc, 1509 struct btrfs_root *root, 1510 struct extent_buffer *leaf) 1511 { 1512 struct btrfs_key key; 1513 struct btrfs_file_extent_item *fi; 1514 struct inode *inode = NULL; 1515 u64 parent; 1516 u64 bytenr; 1517 u64 new_bytenr = 0; 1518 u64 num_bytes; 1519 u64 end; 1520 u32 nritems; 1521 u32 i; 1522 int ret; 1523 int first = 1; 1524 int dirty = 0; 1525 1526 if (rc->stage != UPDATE_DATA_PTRS) 1527 return 0; 1528 1529 /* reloc trees always use full backref */ 1530 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) 1531 parent = leaf->start; 1532 else 1533 parent = 0; 1534 1535 nritems = btrfs_header_nritems(leaf); 1536 for (i = 0; i < nritems; i++) { 1537 cond_resched(); 1538 btrfs_item_key_to_cpu(leaf, &key, i); 1539 if (key.type != BTRFS_EXTENT_DATA_KEY) 1540 continue; 1541 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item); 1542 if (btrfs_file_extent_type(leaf, fi) == 1543 BTRFS_FILE_EXTENT_INLINE) 1544 continue; 1545 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); 1546 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); 1547 if (bytenr == 0) 1548 continue; 1549 if (!in_block_group(bytenr, rc->block_group)) 1550 continue; 1551 1552 /* 1553 * if we are modifying block in fs tree, wait for readpage 1554 * to complete and drop the extent cache 1555 */ 1556 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) { 1557 if (first) { 1558 inode = find_next_inode(root, key.objectid); 1559 first = 0; 1560 } else if (inode && inode->i_ino < key.objectid) { 1561 btrfs_add_delayed_iput(inode); 1562 inode = find_next_inode(root, key.objectid); 1563 } 1564 if (inode && inode->i_ino == key.objectid) { 1565 end = key.offset + 1566 btrfs_file_extent_num_bytes(leaf, fi); 1567 WARN_ON(!IS_ALIGNED(key.offset, 1568 root->sectorsize)); 1569 WARN_ON(!IS_ALIGNED(end, root->sectorsize)); 1570 end--; 1571 ret = try_lock_extent(&BTRFS_I(inode)->io_tree, 1572 key.offset, end, 1573 GFP_NOFS); 1574 if (!ret) 1575 continue; 1576 1577 btrfs_drop_extent_cache(inode, key.offset, end, 1578 1); 1579 unlock_extent(&BTRFS_I(inode)->io_tree, 1580 key.offset, end, GFP_NOFS); 1581 } 1582 } 1583 1584 ret = get_new_location(rc->data_inode, &new_bytenr, 1585 bytenr, num_bytes); 1586 if (ret > 0) { 1587 WARN_ON(1); 1588 continue; 1589 } 1590 BUG_ON(ret < 0); 1591 1592 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr); 1593 dirty = 1; 1594 1595 key.offset -= btrfs_file_extent_offset(leaf, fi); 1596 ret = btrfs_inc_extent_ref(trans, root, new_bytenr, 1597 num_bytes, parent, 1598 btrfs_header_owner(leaf), 1599 key.objectid, key.offset); 1600 BUG_ON(ret); 1601 1602 ret = btrfs_free_extent(trans, root, bytenr, num_bytes, 1603 parent, btrfs_header_owner(leaf), 1604 key.objectid, key.offset); 1605 BUG_ON(ret); 1606 } 1607 if (dirty) 1608 btrfs_mark_buffer_dirty(leaf); 1609 if (inode) 1610 btrfs_add_delayed_iput(inode); 1611 return 0; 1612 } 1613 1614 static noinline_for_stack 1615 int memcmp_node_keys(struct extent_buffer *eb, int slot, 1616 struct btrfs_path *path, int level) 1617 { 1618 struct btrfs_disk_key key1; 1619 struct btrfs_disk_key key2; 1620 btrfs_node_key(eb, &key1, slot); 1621 btrfs_node_key(path->nodes[level], &key2, path->slots[level]); 1622 return memcmp(&key1, &key2, sizeof(key1)); 1623 } 1624 1625 /* 1626 * try to replace tree blocks in fs tree with the new blocks 1627 * in reloc tree. tree blocks haven't been modified since the 1628 * reloc tree was create can be replaced. 1629 * 1630 * if a block was replaced, level of the block + 1 is returned. 1631 * if no block got replaced, 0 is returned. if there are other 1632 * errors, a negative error number is returned. 1633 */ 1634 static noinline_for_stack 1635 int replace_path(struct btrfs_trans_handle *trans, 1636 struct btrfs_root *dest, struct btrfs_root *src, 1637 struct btrfs_path *path, struct btrfs_key *next_key, 1638 int lowest_level, int max_level) 1639 { 1640 struct extent_buffer *eb; 1641 struct extent_buffer *parent; 1642 struct btrfs_key key; 1643 u64 old_bytenr; 1644 u64 new_bytenr; 1645 u64 old_ptr_gen; 1646 u64 new_ptr_gen; 1647 u64 last_snapshot; 1648 u32 blocksize; 1649 int cow = 0; 1650 int level; 1651 int ret; 1652 int slot; 1653 1654 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID); 1655 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID); 1656 1657 last_snapshot = btrfs_root_last_snapshot(&src->root_item); 1658 again: 1659 slot = path->slots[lowest_level]; 1660 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot); 1661 1662 eb = btrfs_lock_root_node(dest); 1663 btrfs_set_lock_blocking(eb); 1664 level = btrfs_header_level(eb); 1665 1666 if (level < lowest_level) { 1667 btrfs_tree_unlock(eb); 1668 free_extent_buffer(eb); 1669 return 0; 1670 } 1671 1672 if (cow) { 1673 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb); 1674 BUG_ON(ret); 1675 } 1676 btrfs_set_lock_blocking(eb); 1677 1678 if (next_key) { 1679 next_key->objectid = (u64)-1; 1680 next_key->type = (u8)-1; 1681 next_key->offset = (u64)-1; 1682 } 1683 1684 parent = eb; 1685 while (1) { 1686 level = btrfs_header_level(parent); 1687 BUG_ON(level < lowest_level); 1688 1689 ret = btrfs_bin_search(parent, &key, level, &slot); 1690 if (ret && slot > 0) 1691 slot--; 1692 1693 if (next_key && slot + 1 < btrfs_header_nritems(parent)) 1694 btrfs_node_key_to_cpu(parent, next_key, slot + 1); 1695 1696 old_bytenr = btrfs_node_blockptr(parent, slot); 1697 blocksize = btrfs_level_size(dest, level - 1); 1698 old_ptr_gen = btrfs_node_ptr_generation(parent, slot); 1699 1700 if (level <= max_level) { 1701 eb = path->nodes[level]; 1702 new_bytenr = btrfs_node_blockptr(eb, 1703 path->slots[level]); 1704 new_ptr_gen = btrfs_node_ptr_generation(eb, 1705 path->slots[level]); 1706 } else { 1707 new_bytenr = 0; 1708 new_ptr_gen = 0; 1709 } 1710 1711 if (new_bytenr > 0 && new_bytenr == old_bytenr) { 1712 WARN_ON(1); 1713 ret = level; 1714 break; 1715 } 1716 1717 if (new_bytenr == 0 || old_ptr_gen > last_snapshot || 1718 memcmp_node_keys(parent, slot, path, level)) { 1719 if (level <= lowest_level) { 1720 ret = 0; 1721 break; 1722 } 1723 1724 eb = read_tree_block(dest, old_bytenr, blocksize, 1725 old_ptr_gen); 1726 btrfs_tree_lock(eb); 1727 if (cow) { 1728 ret = btrfs_cow_block(trans, dest, eb, parent, 1729 slot, &eb); 1730 BUG_ON(ret); 1731 } 1732 btrfs_set_lock_blocking(eb); 1733 1734 btrfs_tree_unlock(parent); 1735 free_extent_buffer(parent); 1736 1737 parent = eb; 1738 continue; 1739 } 1740 1741 if (!cow) { 1742 btrfs_tree_unlock(parent); 1743 free_extent_buffer(parent); 1744 cow = 1; 1745 goto again; 1746 } 1747 1748 btrfs_node_key_to_cpu(path->nodes[level], &key, 1749 path->slots[level]); 1750 btrfs_release_path(src, path); 1751 1752 path->lowest_level = level; 1753 ret = btrfs_search_slot(trans, src, &key, path, 0, 1); 1754 path->lowest_level = 0; 1755 BUG_ON(ret); 1756 1757 /* 1758 * swap blocks in fs tree and reloc tree. 1759 */ 1760 btrfs_set_node_blockptr(parent, slot, new_bytenr); 1761 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen); 1762 btrfs_mark_buffer_dirty(parent); 1763 1764 btrfs_set_node_blockptr(path->nodes[level], 1765 path->slots[level], old_bytenr); 1766 btrfs_set_node_ptr_generation(path->nodes[level], 1767 path->slots[level], old_ptr_gen); 1768 btrfs_mark_buffer_dirty(path->nodes[level]); 1769 1770 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize, 1771 path->nodes[level]->start, 1772 src->root_key.objectid, level - 1, 0); 1773 BUG_ON(ret); 1774 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize, 1775 0, dest->root_key.objectid, level - 1, 1776 0); 1777 BUG_ON(ret); 1778 1779 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize, 1780 path->nodes[level]->start, 1781 src->root_key.objectid, level - 1, 0); 1782 BUG_ON(ret); 1783 1784 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize, 1785 0, dest->root_key.objectid, level - 1, 1786 0); 1787 BUG_ON(ret); 1788 1789 btrfs_unlock_up_safe(path, 0); 1790 1791 ret = level; 1792 break; 1793 } 1794 btrfs_tree_unlock(parent); 1795 free_extent_buffer(parent); 1796 return ret; 1797 } 1798 1799 /* 1800 * helper to find next relocated block in reloc tree 1801 */ 1802 static noinline_for_stack 1803 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path, 1804 int *level) 1805 { 1806 struct extent_buffer *eb; 1807 int i; 1808 u64 last_snapshot; 1809 u32 nritems; 1810 1811 last_snapshot = btrfs_root_last_snapshot(&root->root_item); 1812 1813 for (i = 0; i < *level; i++) { 1814 free_extent_buffer(path->nodes[i]); 1815 path->nodes[i] = NULL; 1816 } 1817 1818 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) { 1819 eb = path->nodes[i]; 1820 nritems = btrfs_header_nritems(eb); 1821 while (path->slots[i] + 1 < nritems) { 1822 path->slots[i]++; 1823 if (btrfs_node_ptr_generation(eb, path->slots[i]) <= 1824 last_snapshot) 1825 continue; 1826 1827 *level = i; 1828 return 0; 1829 } 1830 free_extent_buffer(path->nodes[i]); 1831 path->nodes[i] = NULL; 1832 } 1833 return 1; 1834 } 1835 1836 /* 1837 * walk down reloc tree to find relocated block of lowest level 1838 */ 1839 static noinline_for_stack 1840 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path, 1841 int *level) 1842 { 1843 struct extent_buffer *eb = NULL; 1844 int i; 1845 u64 bytenr; 1846 u64 ptr_gen = 0; 1847 u64 last_snapshot; 1848 u32 blocksize; 1849 u32 nritems; 1850 1851 last_snapshot = btrfs_root_last_snapshot(&root->root_item); 1852 1853 for (i = *level; i > 0; i--) { 1854 eb = path->nodes[i]; 1855 nritems = btrfs_header_nritems(eb); 1856 while (path->slots[i] < nritems) { 1857 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]); 1858 if (ptr_gen > last_snapshot) 1859 break; 1860 path->slots[i]++; 1861 } 1862 if (path->slots[i] >= nritems) { 1863 if (i == *level) 1864 break; 1865 *level = i + 1; 1866 return 0; 1867 } 1868 if (i == 1) { 1869 *level = i; 1870 return 0; 1871 } 1872 1873 bytenr = btrfs_node_blockptr(eb, path->slots[i]); 1874 blocksize = btrfs_level_size(root, i - 1); 1875 eb = read_tree_block(root, bytenr, blocksize, ptr_gen); 1876 BUG_ON(btrfs_header_level(eb) != i - 1); 1877 path->nodes[i - 1] = eb; 1878 path->slots[i - 1] = 0; 1879 } 1880 return 1; 1881 } 1882 1883 /* 1884 * invalidate extent cache for file extents whose key in range of 1885 * [min_key, max_key) 1886 */ 1887 static int invalidate_extent_cache(struct btrfs_root *root, 1888 struct btrfs_key *min_key, 1889 struct btrfs_key *max_key) 1890 { 1891 struct inode *inode = NULL; 1892 u64 objectid; 1893 u64 start, end; 1894 1895 objectid = min_key->objectid; 1896 while (1) { 1897 cond_resched(); 1898 iput(inode); 1899 1900 if (objectid > max_key->objectid) 1901 break; 1902 1903 inode = find_next_inode(root, objectid); 1904 if (!inode) 1905 break; 1906 1907 if (inode->i_ino > max_key->objectid) { 1908 iput(inode); 1909 break; 1910 } 1911 1912 objectid = inode->i_ino + 1; 1913 if (!S_ISREG(inode->i_mode)) 1914 continue; 1915 1916 if (unlikely(min_key->objectid == inode->i_ino)) { 1917 if (min_key->type > BTRFS_EXTENT_DATA_KEY) 1918 continue; 1919 if (min_key->type < BTRFS_EXTENT_DATA_KEY) 1920 start = 0; 1921 else { 1922 start = min_key->offset; 1923 WARN_ON(!IS_ALIGNED(start, root->sectorsize)); 1924 } 1925 } else { 1926 start = 0; 1927 } 1928 1929 if (unlikely(max_key->objectid == inode->i_ino)) { 1930 if (max_key->type < BTRFS_EXTENT_DATA_KEY) 1931 continue; 1932 if (max_key->type > BTRFS_EXTENT_DATA_KEY) { 1933 end = (u64)-1; 1934 } else { 1935 if (max_key->offset == 0) 1936 continue; 1937 end = max_key->offset; 1938 WARN_ON(!IS_ALIGNED(end, root->sectorsize)); 1939 end--; 1940 } 1941 } else { 1942 end = (u64)-1; 1943 } 1944 1945 /* the lock_extent waits for readpage to complete */ 1946 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); 1947 btrfs_drop_extent_cache(inode, start, end, 1); 1948 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); 1949 } 1950 return 0; 1951 } 1952 1953 static int find_next_key(struct btrfs_path *path, int level, 1954 struct btrfs_key *key) 1955 1956 { 1957 while (level < BTRFS_MAX_LEVEL) { 1958 if (!path->nodes[level]) 1959 break; 1960 if (path->slots[level] + 1 < 1961 btrfs_header_nritems(path->nodes[level])) { 1962 btrfs_node_key_to_cpu(path->nodes[level], key, 1963 path->slots[level] + 1); 1964 return 0; 1965 } 1966 level++; 1967 } 1968 return 1; 1969 } 1970 1971 /* 1972 * merge the relocated tree blocks in reloc tree with corresponding 1973 * fs tree. 1974 */ 1975 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc, 1976 struct btrfs_root *root) 1977 { 1978 LIST_HEAD(inode_list); 1979 struct btrfs_key key; 1980 struct btrfs_key next_key; 1981 struct btrfs_trans_handle *trans; 1982 struct btrfs_root *reloc_root; 1983 struct btrfs_root_item *root_item; 1984 struct btrfs_path *path; 1985 struct extent_buffer *leaf; 1986 unsigned long nr; 1987 int level; 1988 int max_level; 1989 int replaced = 0; 1990 int ret; 1991 int err = 0; 1992 u32 min_reserved; 1993 1994 path = btrfs_alloc_path(); 1995 if (!path) 1996 return -ENOMEM; 1997 1998 reloc_root = root->reloc_root; 1999 root_item = &reloc_root->root_item; 2000 2001 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) { 2002 level = btrfs_root_level(root_item); 2003 extent_buffer_get(reloc_root->node); 2004 path->nodes[level] = reloc_root->node; 2005 path->slots[level] = 0; 2006 } else { 2007 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress); 2008 2009 level = root_item->drop_level; 2010 BUG_ON(level == 0); 2011 path->lowest_level = level; 2012 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0); 2013 path->lowest_level = 0; 2014 if (ret < 0) { 2015 btrfs_free_path(path); 2016 return ret; 2017 } 2018 2019 btrfs_node_key_to_cpu(path->nodes[level], &next_key, 2020 path->slots[level]); 2021 WARN_ON(memcmp(&key, &next_key, sizeof(key))); 2022 2023 btrfs_unlock_up_safe(path, 0); 2024 } 2025 2026 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2; 2027 memset(&next_key, 0, sizeof(next_key)); 2028 2029 while (1) { 2030 trans = btrfs_start_transaction(root, 0); 2031 trans->block_rsv = rc->block_rsv; 2032 2033 ret = btrfs_block_rsv_check(trans, root, rc->block_rsv, 2034 min_reserved, 0); 2035 if (ret) { 2036 BUG_ON(ret != -EAGAIN); 2037 ret = btrfs_commit_transaction(trans, root); 2038 BUG_ON(ret); 2039 continue; 2040 } 2041 2042 replaced = 0; 2043 max_level = level; 2044 2045 ret = walk_down_reloc_tree(reloc_root, path, &level); 2046 if (ret < 0) { 2047 err = ret; 2048 goto out; 2049 } 2050 if (ret > 0) 2051 break; 2052 2053 if (!find_next_key(path, level, &key) && 2054 btrfs_comp_cpu_keys(&next_key, &key) >= 0) { 2055 ret = 0; 2056 } else { 2057 ret = replace_path(trans, root, reloc_root, path, 2058 &next_key, level, max_level); 2059 } 2060 if (ret < 0) { 2061 err = ret; 2062 goto out; 2063 } 2064 2065 if (ret > 0) { 2066 level = ret; 2067 btrfs_node_key_to_cpu(path->nodes[level], &key, 2068 path->slots[level]); 2069 replaced = 1; 2070 } 2071 2072 ret = walk_up_reloc_tree(reloc_root, path, &level); 2073 if (ret > 0) 2074 break; 2075 2076 BUG_ON(level == 0); 2077 /* 2078 * save the merging progress in the drop_progress. 2079 * this is OK since root refs == 1 in this case. 2080 */ 2081 btrfs_node_key(path->nodes[level], &root_item->drop_progress, 2082 path->slots[level]); 2083 root_item->drop_level = level; 2084 2085 nr = trans->blocks_used; 2086 btrfs_end_transaction_throttle(trans, root); 2087 2088 btrfs_btree_balance_dirty(root, nr); 2089 2090 if (replaced && rc->stage == UPDATE_DATA_PTRS) 2091 invalidate_extent_cache(root, &key, &next_key); 2092 } 2093 2094 /* 2095 * handle the case only one block in the fs tree need to be 2096 * relocated and the block is tree root. 2097 */ 2098 leaf = btrfs_lock_root_node(root); 2099 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf); 2100 btrfs_tree_unlock(leaf); 2101 free_extent_buffer(leaf); 2102 if (ret < 0) 2103 err = ret; 2104 out: 2105 btrfs_free_path(path); 2106 2107 if (err == 0) { 2108 memset(&root_item->drop_progress, 0, 2109 sizeof(root_item->drop_progress)); 2110 root_item->drop_level = 0; 2111 btrfs_set_root_refs(root_item, 0); 2112 btrfs_update_reloc_root(trans, root); 2113 } 2114 2115 nr = trans->blocks_used; 2116 btrfs_end_transaction_throttle(trans, root); 2117 2118 btrfs_btree_balance_dirty(root, nr); 2119 2120 if (replaced && rc->stage == UPDATE_DATA_PTRS) 2121 invalidate_extent_cache(root, &key, &next_key); 2122 2123 return err; 2124 } 2125 2126 static noinline_for_stack 2127 int prepare_to_merge(struct reloc_control *rc, int err) 2128 { 2129 struct btrfs_root *root = rc->extent_root; 2130 struct btrfs_root *reloc_root; 2131 struct btrfs_trans_handle *trans; 2132 LIST_HEAD(reloc_roots); 2133 u64 num_bytes = 0; 2134 int ret; 2135 2136 mutex_lock(&root->fs_info->trans_mutex); 2137 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2; 2138 rc->merging_rsv_size += rc->nodes_relocated * 2; 2139 mutex_unlock(&root->fs_info->trans_mutex); 2140 again: 2141 if (!err) { 2142 num_bytes = rc->merging_rsv_size; 2143 ret = btrfs_block_rsv_add(NULL, root, rc->block_rsv, 2144 num_bytes); 2145 if (ret) 2146 err = ret; 2147 } 2148 2149 trans = btrfs_join_transaction(rc->extent_root, 1); 2150 2151 if (!err) { 2152 if (num_bytes != rc->merging_rsv_size) { 2153 btrfs_end_transaction(trans, rc->extent_root); 2154 btrfs_block_rsv_release(rc->extent_root, 2155 rc->block_rsv, num_bytes); 2156 goto again; 2157 } 2158 } 2159 2160 rc->merge_reloc_tree = 1; 2161 2162 while (!list_empty(&rc->reloc_roots)) { 2163 reloc_root = list_entry(rc->reloc_roots.next, 2164 struct btrfs_root, root_list); 2165 list_del_init(&reloc_root->root_list); 2166 2167 root = read_fs_root(reloc_root->fs_info, 2168 reloc_root->root_key.offset); 2169 BUG_ON(IS_ERR(root)); 2170 BUG_ON(root->reloc_root != reloc_root); 2171 2172 /* 2173 * set reference count to 1, so btrfs_recover_relocation 2174 * knows it should resumes merging 2175 */ 2176 if (!err) 2177 btrfs_set_root_refs(&reloc_root->root_item, 1); 2178 btrfs_update_reloc_root(trans, root); 2179 2180 list_add(&reloc_root->root_list, &reloc_roots); 2181 } 2182 2183 list_splice(&reloc_roots, &rc->reloc_roots); 2184 2185 if (!err) 2186 btrfs_commit_transaction(trans, rc->extent_root); 2187 else 2188 btrfs_end_transaction(trans, rc->extent_root); 2189 return err; 2190 } 2191 2192 static noinline_for_stack 2193 int merge_reloc_roots(struct reloc_control *rc) 2194 { 2195 struct btrfs_root *root; 2196 struct btrfs_root *reloc_root; 2197 LIST_HEAD(reloc_roots); 2198 int found = 0; 2199 int ret; 2200 again: 2201 root = rc->extent_root; 2202 mutex_lock(&root->fs_info->trans_mutex); 2203 list_splice_init(&rc->reloc_roots, &reloc_roots); 2204 mutex_unlock(&root->fs_info->trans_mutex); 2205 2206 while (!list_empty(&reloc_roots)) { 2207 found = 1; 2208 reloc_root = list_entry(reloc_roots.next, 2209 struct btrfs_root, root_list); 2210 2211 if (btrfs_root_refs(&reloc_root->root_item) > 0) { 2212 root = read_fs_root(reloc_root->fs_info, 2213 reloc_root->root_key.offset); 2214 BUG_ON(IS_ERR(root)); 2215 BUG_ON(root->reloc_root != reloc_root); 2216 2217 ret = merge_reloc_root(rc, root); 2218 BUG_ON(ret); 2219 } else { 2220 list_del_init(&reloc_root->root_list); 2221 } 2222 btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0); 2223 } 2224 2225 if (found) { 2226 found = 0; 2227 goto again; 2228 } 2229 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root)); 2230 return 0; 2231 } 2232 2233 static void free_block_list(struct rb_root *blocks) 2234 { 2235 struct tree_block *block; 2236 struct rb_node *rb_node; 2237 while ((rb_node = rb_first(blocks))) { 2238 block = rb_entry(rb_node, struct tree_block, rb_node); 2239 rb_erase(rb_node, blocks); 2240 kfree(block); 2241 } 2242 } 2243 2244 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans, 2245 struct btrfs_root *reloc_root) 2246 { 2247 struct btrfs_root *root; 2248 2249 if (reloc_root->last_trans == trans->transid) 2250 return 0; 2251 2252 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset); 2253 BUG_ON(IS_ERR(root)); 2254 BUG_ON(root->reloc_root != reloc_root); 2255 2256 return btrfs_record_root_in_trans(trans, root); 2257 } 2258 2259 static noinline_for_stack 2260 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, 2261 struct reloc_control *rc, 2262 struct backref_node *node, 2263 struct backref_edge *edges[], int *nr) 2264 { 2265 struct backref_node *next; 2266 struct btrfs_root *root; 2267 int index = 0; 2268 2269 next = node; 2270 while (1) { 2271 cond_resched(); 2272 next = walk_up_backref(next, edges, &index); 2273 root = next->root; 2274 BUG_ON(!root); 2275 BUG_ON(!root->ref_cows); 2276 2277 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { 2278 record_reloc_root_in_trans(trans, root); 2279 break; 2280 } 2281 2282 btrfs_record_root_in_trans(trans, root); 2283 root = root->reloc_root; 2284 2285 if (next->new_bytenr != root->node->start) { 2286 BUG_ON(next->new_bytenr); 2287 BUG_ON(!list_empty(&next->list)); 2288 next->new_bytenr = root->node->start; 2289 next->root = root; 2290 list_add_tail(&next->list, 2291 &rc->backref_cache.changed); 2292 __mark_block_processed(rc, next); 2293 break; 2294 } 2295 2296 WARN_ON(1); 2297 root = NULL; 2298 next = walk_down_backref(edges, &index); 2299 if (!next || next->level <= node->level) 2300 break; 2301 } 2302 if (!root) 2303 return NULL; 2304 2305 *nr = index; 2306 next = node; 2307 /* setup backref node path for btrfs_reloc_cow_block */ 2308 while (1) { 2309 rc->backref_cache.path[next->level] = next; 2310 if (--index < 0) 2311 break; 2312 next = edges[index]->node[UPPER]; 2313 } 2314 return root; 2315 } 2316 2317 /* 2318 * select a tree root for relocation. return NULL if the block 2319 * is reference counted. we should use do_relocation() in this 2320 * case. return a tree root pointer if the block isn't reference 2321 * counted. return -ENOENT if the block is root of reloc tree. 2322 */ 2323 static noinline_for_stack 2324 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans, 2325 struct backref_node *node) 2326 { 2327 struct backref_node *next; 2328 struct btrfs_root *root; 2329 struct btrfs_root *fs_root = NULL; 2330 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; 2331 int index = 0; 2332 2333 next = node; 2334 while (1) { 2335 cond_resched(); 2336 next = walk_up_backref(next, edges, &index); 2337 root = next->root; 2338 BUG_ON(!root); 2339 2340 /* no other choice for non-refernce counted tree */ 2341 if (!root->ref_cows) 2342 return root; 2343 2344 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) 2345 fs_root = root; 2346 2347 if (next != node) 2348 return NULL; 2349 2350 next = walk_down_backref(edges, &index); 2351 if (!next || next->level <= node->level) 2352 break; 2353 } 2354 2355 if (!fs_root) 2356 return ERR_PTR(-ENOENT); 2357 return fs_root; 2358 } 2359 2360 static noinline_for_stack 2361 u64 calcu_metadata_size(struct reloc_control *rc, 2362 struct backref_node *node, int reserve) 2363 { 2364 struct backref_node *next = node; 2365 struct backref_edge *edge; 2366 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; 2367 u64 num_bytes = 0; 2368 int index = 0; 2369 2370 BUG_ON(reserve && node->processed); 2371 2372 while (next) { 2373 cond_resched(); 2374 while (1) { 2375 if (next->processed && (reserve || next != node)) 2376 break; 2377 2378 num_bytes += btrfs_level_size(rc->extent_root, 2379 next->level); 2380 2381 if (list_empty(&next->upper)) 2382 break; 2383 2384 edge = list_entry(next->upper.next, 2385 struct backref_edge, list[LOWER]); 2386 edges[index++] = edge; 2387 next = edge->node[UPPER]; 2388 } 2389 next = walk_down_backref(edges, &index); 2390 } 2391 return num_bytes; 2392 } 2393 2394 static int reserve_metadata_space(struct btrfs_trans_handle *trans, 2395 struct reloc_control *rc, 2396 struct backref_node *node) 2397 { 2398 struct btrfs_root *root = rc->extent_root; 2399 u64 num_bytes; 2400 int ret; 2401 2402 num_bytes = calcu_metadata_size(rc, node, 1) * 2; 2403 2404 trans->block_rsv = rc->block_rsv; 2405 ret = btrfs_block_rsv_add(trans, root, rc->block_rsv, num_bytes); 2406 if (ret) { 2407 if (ret == -EAGAIN) 2408 rc->commit_transaction = 1; 2409 return ret; 2410 } 2411 2412 return 0; 2413 } 2414 2415 static void release_metadata_space(struct reloc_control *rc, 2416 struct backref_node *node) 2417 { 2418 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2; 2419 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes); 2420 } 2421 2422 /* 2423 * relocate a block tree, and then update pointers in upper level 2424 * blocks that reference the block to point to the new location. 2425 * 2426 * if called by link_to_upper, the block has already been relocated. 2427 * in that case this function just updates pointers. 2428 */ 2429 static int do_relocation(struct btrfs_trans_handle *trans, 2430 struct reloc_control *rc, 2431 struct backref_node *node, 2432 struct btrfs_key *key, 2433 struct btrfs_path *path, int lowest) 2434 { 2435 struct backref_node *upper; 2436 struct backref_edge *edge; 2437 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; 2438 struct btrfs_root *root; 2439 struct extent_buffer *eb; 2440 u32 blocksize; 2441 u64 bytenr; 2442 u64 generation; 2443 int nr; 2444 int slot; 2445 int ret; 2446 int err = 0; 2447 2448 BUG_ON(lowest && node->eb); 2449 2450 path->lowest_level = node->level + 1; 2451 rc->backref_cache.path[node->level] = node; 2452 list_for_each_entry(edge, &node->upper, list[LOWER]) { 2453 cond_resched(); 2454 2455 upper = edge->node[UPPER]; 2456 root = select_reloc_root(trans, rc, upper, edges, &nr); 2457 BUG_ON(!root); 2458 2459 if (upper->eb && !upper->locked) { 2460 if (!lowest) { 2461 ret = btrfs_bin_search(upper->eb, key, 2462 upper->level, &slot); 2463 BUG_ON(ret); 2464 bytenr = btrfs_node_blockptr(upper->eb, slot); 2465 if (node->eb->start == bytenr) 2466 goto next; 2467 } 2468 drop_node_buffer(upper); 2469 } 2470 2471 if (!upper->eb) { 2472 ret = btrfs_search_slot(trans, root, key, path, 0, 1); 2473 if (ret < 0) { 2474 err = ret; 2475 break; 2476 } 2477 BUG_ON(ret > 0); 2478 2479 if (!upper->eb) { 2480 upper->eb = path->nodes[upper->level]; 2481 path->nodes[upper->level] = NULL; 2482 } else { 2483 BUG_ON(upper->eb != path->nodes[upper->level]); 2484 } 2485 2486 upper->locked = 1; 2487 path->locks[upper->level] = 0; 2488 2489 slot = path->slots[upper->level]; 2490 btrfs_release_path(NULL, path); 2491 } else { 2492 ret = btrfs_bin_search(upper->eb, key, upper->level, 2493 &slot); 2494 BUG_ON(ret); 2495 } 2496 2497 bytenr = btrfs_node_blockptr(upper->eb, slot); 2498 if (lowest) { 2499 BUG_ON(bytenr != node->bytenr); 2500 } else { 2501 if (node->eb->start == bytenr) 2502 goto next; 2503 } 2504 2505 blocksize = btrfs_level_size(root, node->level); 2506 generation = btrfs_node_ptr_generation(upper->eb, slot); 2507 eb = read_tree_block(root, bytenr, blocksize, generation); 2508 btrfs_tree_lock(eb); 2509 btrfs_set_lock_blocking(eb); 2510 2511 if (!node->eb) { 2512 ret = btrfs_cow_block(trans, root, eb, upper->eb, 2513 slot, &eb); 2514 btrfs_tree_unlock(eb); 2515 free_extent_buffer(eb); 2516 if (ret < 0) { 2517 err = ret; 2518 goto next; 2519 } 2520 BUG_ON(node->eb != eb); 2521 } else { 2522 btrfs_set_node_blockptr(upper->eb, slot, 2523 node->eb->start); 2524 btrfs_set_node_ptr_generation(upper->eb, slot, 2525 trans->transid); 2526 btrfs_mark_buffer_dirty(upper->eb); 2527 2528 ret = btrfs_inc_extent_ref(trans, root, 2529 node->eb->start, blocksize, 2530 upper->eb->start, 2531 btrfs_header_owner(upper->eb), 2532 node->level, 0); 2533 BUG_ON(ret); 2534 2535 ret = btrfs_drop_subtree(trans, root, eb, upper->eb); 2536 BUG_ON(ret); 2537 } 2538 next: 2539 if (!upper->pending) 2540 drop_node_buffer(upper); 2541 else 2542 unlock_node_buffer(upper); 2543 if (err) 2544 break; 2545 } 2546 2547 if (!err && node->pending) { 2548 drop_node_buffer(node); 2549 list_move_tail(&node->list, &rc->backref_cache.changed); 2550 node->pending = 0; 2551 } 2552 2553 path->lowest_level = 0; 2554 BUG_ON(err == -ENOSPC); 2555 return err; 2556 } 2557 2558 static int link_to_upper(struct btrfs_trans_handle *trans, 2559 struct reloc_control *rc, 2560 struct backref_node *node, 2561 struct btrfs_path *path) 2562 { 2563 struct btrfs_key key; 2564 2565 btrfs_node_key_to_cpu(node->eb, &key, 0); 2566 return do_relocation(trans, rc, node, &key, path, 0); 2567 } 2568 2569 static int finish_pending_nodes(struct btrfs_trans_handle *trans, 2570 struct reloc_control *rc, 2571 struct btrfs_path *path, int err) 2572 { 2573 LIST_HEAD(list); 2574 struct backref_cache *cache = &rc->backref_cache; 2575 struct backref_node *node; 2576 int level; 2577 int ret; 2578 2579 for (level = 0; level < BTRFS_MAX_LEVEL; level++) { 2580 while (!list_empty(&cache->pending[level])) { 2581 node = list_entry(cache->pending[level].next, 2582 struct backref_node, list); 2583 list_move_tail(&node->list, &list); 2584 BUG_ON(!node->pending); 2585 2586 if (!err) { 2587 ret = link_to_upper(trans, rc, node, path); 2588 if (ret < 0) 2589 err = ret; 2590 } 2591 } 2592 list_splice_init(&list, &cache->pending[level]); 2593 } 2594 return err; 2595 } 2596 2597 static void mark_block_processed(struct reloc_control *rc, 2598 u64 bytenr, u32 blocksize) 2599 { 2600 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1, 2601 EXTENT_DIRTY, GFP_NOFS); 2602 } 2603 2604 static void __mark_block_processed(struct reloc_control *rc, 2605 struct backref_node *node) 2606 { 2607 u32 blocksize; 2608 if (node->level == 0 || 2609 in_block_group(node->bytenr, rc->block_group)) { 2610 blocksize = btrfs_level_size(rc->extent_root, node->level); 2611 mark_block_processed(rc, node->bytenr, blocksize); 2612 } 2613 node->processed = 1; 2614 } 2615 2616 /* 2617 * mark a block and all blocks directly/indirectly reference the block 2618 * as processed. 2619 */ 2620 static void update_processed_blocks(struct reloc_control *rc, 2621 struct backref_node *node) 2622 { 2623 struct backref_node *next = node; 2624 struct backref_edge *edge; 2625 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; 2626 int index = 0; 2627 2628 while (next) { 2629 cond_resched(); 2630 while (1) { 2631 if (next->processed) 2632 break; 2633 2634 __mark_block_processed(rc, next); 2635 2636 if (list_empty(&next->upper)) 2637 break; 2638 2639 edge = list_entry(next->upper.next, 2640 struct backref_edge, list[LOWER]); 2641 edges[index++] = edge; 2642 next = edge->node[UPPER]; 2643 } 2644 next = walk_down_backref(edges, &index); 2645 } 2646 } 2647 2648 static int tree_block_processed(u64 bytenr, u32 blocksize, 2649 struct reloc_control *rc) 2650 { 2651 if (test_range_bit(&rc->processed_blocks, bytenr, 2652 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL)) 2653 return 1; 2654 return 0; 2655 } 2656 2657 static int get_tree_block_key(struct reloc_control *rc, 2658 struct tree_block *block) 2659 { 2660 struct extent_buffer *eb; 2661 2662 BUG_ON(block->key_ready); 2663 eb = read_tree_block(rc->extent_root, block->bytenr, 2664 block->key.objectid, block->key.offset); 2665 WARN_ON(btrfs_header_level(eb) != block->level); 2666 if (block->level == 0) 2667 btrfs_item_key_to_cpu(eb, &block->key, 0); 2668 else 2669 btrfs_node_key_to_cpu(eb, &block->key, 0); 2670 free_extent_buffer(eb); 2671 block->key_ready = 1; 2672 return 0; 2673 } 2674 2675 static int reada_tree_block(struct reloc_control *rc, 2676 struct tree_block *block) 2677 { 2678 BUG_ON(block->key_ready); 2679 readahead_tree_block(rc->extent_root, block->bytenr, 2680 block->key.objectid, block->key.offset); 2681 return 0; 2682 } 2683 2684 /* 2685 * helper function to relocate a tree block 2686 */ 2687 static int relocate_tree_block(struct btrfs_trans_handle *trans, 2688 struct reloc_control *rc, 2689 struct backref_node *node, 2690 struct btrfs_key *key, 2691 struct btrfs_path *path) 2692 { 2693 struct btrfs_root *root; 2694 int release = 0; 2695 int ret = 0; 2696 2697 if (!node) 2698 return 0; 2699 2700 BUG_ON(node->processed); 2701 root = select_one_root(trans, node); 2702 if (root == ERR_PTR(-ENOENT)) { 2703 update_processed_blocks(rc, node); 2704 goto out; 2705 } 2706 2707 if (!root || root->ref_cows) { 2708 ret = reserve_metadata_space(trans, rc, node); 2709 if (ret) 2710 goto out; 2711 release = 1; 2712 } 2713 2714 if (root) { 2715 if (root->ref_cows) { 2716 BUG_ON(node->new_bytenr); 2717 BUG_ON(!list_empty(&node->list)); 2718 btrfs_record_root_in_trans(trans, root); 2719 root = root->reloc_root; 2720 node->new_bytenr = root->node->start; 2721 node->root = root; 2722 list_add_tail(&node->list, &rc->backref_cache.changed); 2723 } else { 2724 path->lowest_level = node->level; 2725 ret = btrfs_search_slot(trans, root, key, path, 0, 1); 2726 btrfs_release_path(root, path); 2727 if (ret > 0) 2728 ret = 0; 2729 } 2730 if (!ret) 2731 update_processed_blocks(rc, node); 2732 } else { 2733 ret = do_relocation(trans, rc, node, key, path, 1); 2734 } 2735 out: 2736 if (ret || node->level == 0 || node->cowonly) { 2737 if (release) 2738 release_metadata_space(rc, node); 2739 remove_backref_node(&rc->backref_cache, node); 2740 } 2741 return ret; 2742 } 2743 2744 /* 2745 * relocate a list of blocks 2746 */ 2747 static noinline_for_stack 2748 int relocate_tree_blocks(struct btrfs_trans_handle *trans, 2749 struct reloc_control *rc, struct rb_root *blocks) 2750 { 2751 struct backref_node *node; 2752 struct btrfs_path *path; 2753 struct tree_block *block; 2754 struct rb_node *rb_node; 2755 int ret; 2756 int err = 0; 2757 2758 path = btrfs_alloc_path(); 2759 if (!path) 2760 return -ENOMEM; 2761 2762 rb_node = rb_first(blocks); 2763 while (rb_node) { 2764 block = rb_entry(rb_node, struct tree_block, rb_node); 2765 if (!block->key_ready) 2766 reada_tree_block(rc, block); 2767 rb_node = rb_next(rb_node); 2768 } 2769 2770 rb_node = rb_first(blocks); 2771 while (rb_node) { 2772 block = rb_entry(rb_node, struct tree_block, rb_node); 2773 if (!block->key_ready) 2774 get_tree_block_key(rc, block); 2775 rb_node = rb_next(rb_node); 2776 } 2777 2778 rb_node = rb_first(blocks); 2779 while (rb_node) { 2780 block = rb_entry(rb_node, struct tree_block, rb_node); 2781 2782 node = build_backref_tree(rc, &block->key, 2783 block->level, block->bytenr); 2784 if (IS_ERR(node)) { 2785 err = PTR_ERR(node); 2786 goto out; 2787 } 2788 2789 ret = relocate_tree_block(trans, rc, node, &block->key, 2790 path); 2791 if (ret < 0) { 2792 if (ret != -EAGAIN || rb_node == rb_first(blocks)) 2793 err = ret; 2794 goto out; 2795 } 2796 rb_node = rb_next(rb_node); 2797 } 2798 out: 2799 free_block_list(blocks); 2800 err = finish_pending_nodes(trans, rc, path, err); 2801 2802 btrfs_free_path(path); 2803 return err; 2804 } 2805 2806 static noinline_for_stack 2807 int prealloc_file_extent_cluster(struct inode *inode, 2808 struct file_extent_cluster *cluster) 2809 { 2810 u64 alloc_hint = 0; 2811 u64 start; 2812 u64 end; 2813 u64 offset = BTRFS_I(inode)->index_cnt; 2814 u64 num_bytes; 2815 int nr = 0; 2816 int ret = 0; 2817 2818 BUG_ON(cluster->start != cluster->boundary[0]); 2819 mutex_lock(&inode->i_mutex); 2820 2821 ret = btrfs_check_data_free_space(inode, cluster->end + 2822 1 - cluster->start); 2823 if (ret) 2824 goto out; 2825 2826 while (nr < cluster->nr) { 2827 start = cluster->boundary[nr] - offset; 2828 if (nr + 1 < cluster->nr) 2829 end = cluster->boundary[nr + 1] - 1 - offset; 2830 else 2831 end = cluster->end - offset; 2832 2833 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); 2834 num_bytes = end + 1 - start; 2835 ret = btrfs_prealloc_file_range(inode, 0, start, 2836 num_bytes, num_bytes, 2837 end + 1, &alloc_hint); 2838 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); 2839 if (ret) 2840 break; 2841 nr++; 2842 } 2843 btrfs_free_reserved_data_space(inode, cluster->end + 2844 1 - cluster->start); 2845 out: 2846 mutex_unlock(&inode->i_mutex); 2847 return ret; 2848 } 2849 2850 static noinline_for_stack 2851 int setup_extent_mapping(struct inode *inode, u64 start, u64 end, 2852 u64 block_start) 2853 { 2854 struct btrfs_root *root = BTRFS_I(inode)->root; 2855 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; 2856 struct extent_map *em; 2857 int ret = 0; 2858 2859 em = alloc_extent_map(GFP_NOFS); 2860 if (!em) 2861 return -ENOMEM; 2862 2863 em->start = start; 2864 em->len = end + 1 - start; 2865 em->block_len = em->len; 2866 em->block_start = block_start; 2867 em->bdev = root->fs_info->fs_devices->latest_bdev; 2868 set_bit(EXTENT_FLAG_PINNED, &em->flags); 2869 2870 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); 2871 while (1) { 2872 write_lock(&em_tree->lock); 2873 ret = add_extent_mapping(em_tree, em); 2874 write_unlock(&em_tree->lock); 2875 if (ret != -EEXIST) { 2876 free_extent_map(em); 2877 break; 2878 } 2879 btrfs_drop_extent_cache(inode, start, end, 0); 2880 } 2881 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); 2882 return ret; 2883 } 2884 2885 static int relocate_file_extent_cluster(struct inode *inode, 2886 struct file_extent_cluster *cluster) 2887 { 2888 u64 page_start; 2889 u64 page_end; 2890 u64 offset = BTRFS_I(inode)->index_cnt; 2891 unsigned long index; 2892 unsigned long last_index; 2893 struct page *page; 2894 struct file_ra_state *ra; 2895 int nr = 0; 2896 int ret = 0; 2897 2898 if (!cluster->nr) 2899 return 0; 2900 2901 ra = kzalloc(sizeof(*ra), GFP_NOFS); 2902 if (!ra) 2903 return -ENOMEM; 2904 2905 ret = prealloc_file_extent_cluster(inode, cluster); 2906 if (ret) 2907 goto out; 2908 2909 file_ra_state_init(ra, inode->i_mapping); 2910 2911 ret = setup_extent_mapping(inode, cluster->start - offset, 2912 cluster->end - offset, cluster->start); 2913 if (ret) 2914 goto out; 2915 2916 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT; 2917 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT; 2918 while (index <= last_index) { 2919 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE); 2920 if (ret) 2921 goto out; 2922 2923 page = find_lock_page(inode->i_mapping, index); 2924 if (!page) { 2925 page_cache_sync_readahead(inode->i_mapping, 2926 ra, NULL, index, 2927 last_index + 1 - index); 2928 page = grab_cache_page(inode->i_mapping, index); 2929 if (!page) { 2930 btrfs_delalloc_release_metadata(inode, 2931 PAGE_CACHE_SIZE); 2932 ret = -ENOMEM; 2933 goto out; 2934 } 2935 } 2936 2937 if (PageReadahead(page)) { 2938 page_cache_async_readahead(inode->i_mapping, 2939 ra, NULL, page, index, 2940 last_index + 1 - index); 2941 } 2942 2943 if (!PageUptodate(page)) { 2944 btrfs_readpage(NULL, page); 2945 lock_page(page); 2946 if (!PageUptodate(page)) { 2947 unlock_page(page); 2948 page_cache_release(page); 2949 btrfs_delalloc_release_metadata(inode, 2950 PAGE_CACHE_SIZE); 2951 ret = -EIO; 2952 goto out; 2953 } 2954 } 2955 2956 page_start = (u64)page->index << PAGE_CACHE_SHIFT; 2957 page_end = page_start + PAGE_CACHE_SIZE - 1; 2958 2959 lock_extent(&BTRFS_I(inode)->io_tree, 2960 page_start, page_end, GFP_NOFS); 2961 2962 set_page_extent_mapped(page); 2963 2964 if (nr < cluster->nr && 2965 page_start + offset == cluster->boundary[nr]) { 2966 set_extent_bits(&BTRFS_I(inode)->io_tree, 2967 page_start, page_end, 2968 EXTENT_BOUNDARY, GFP_NOFS); 2969 nr++; 2970 } 2971 2972 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL); 2973 set_page_dirty(page); 2974 2975 unlock_extent(&BTRFS_I(inode)->io_tree, 2976 page_start, page_end, GFP_NOFS); 2977 unlock_page(page); 2978 page_cache_release(page); 2979 2980 index++; 2981 balance_dirty_pages_ratelimited(inode->i_mapping); 2982 btrfs_throttle(BTRFS_I(inode)->root); 2983 } 2984 WARN_ON(nr != cluster->nr); 2985 out: 2986 kfree(ra); 2987 return ret; 2988 } 2989 2990 static noinline_for_stack 2991 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key, 2992 struct file_extent_cluster *cluster) 2993 { 2994 int ret; 2995 2996 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) { 2997 ret = relocate_file_extent_cluster(inode, cluster); 2998 if (ret) 2999 return ret; 3000 cluster->nr = 0; 3001 } 3002 3003 if (!cluster->nr) 3004 cluster->start = extent_key->objectid; 3005 else 3006 BUG_ON(cluster->nr >= MAX_EXTENTS); 3007 cluster->end = extent_key->objectid + extent_key->offset - 1; 3008 cluster->boundary[cluster->nr] = extent_key->objectid; 3009 cluster->nr++; 3010 3011 if (cluster->nr >= MAX_EXTENTS) { 3012 ret = relocate_file_extent_cluster(inode, cluster); 3013 if (ret) 3014 return ret; 3015 cluster->nr = 0; 3016 } 3017 return 0; 3018 } 3019 3020 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 3021 static int get_ref_objectid_v0(struct reloc_control *rc, 3022 struct btrfs_path *path, 3023 struct btrfs_key *extent_key, 3024 u64 *ref_objectid, int *path_change) 3025 { 3026 struct btrfs_key key; 3027 struct extent_buffer *leaf; 3028 struct btrfs_extent_ref_v0 *ref0; 3029 int ret; 3030 int slot; 3031 3032 leaf = path->nodes[0]; 3033 slot = path->slots[0]; 3034 while (1) { 3035 if (slot >= btrfs_header_nritems(leaf)) { 3036 ret = btrfs_next_leaf(rc->extent_root, path); 3037 if (ret < 0) 3038 return ret; 3039 BUG_ON(ret > 0); 3040 leaf = path->nodes[0]; 3041 slot = path->slots[0]; 3042 if (path_change) 3043 *path_change = 1; 3044 } 3045 btrfs_item_key_to_cpu(leaf, &key, slot); 3046 if (key.objectid != extent_key->objectid) 3047 return -ENOENT; 3048 3049 if (key.type != BTRFS_EXTENT_REF_V0_KEY) { 3050 slot++; 3051 continue; 3052 } 3053 ref0 = btrfs_item_ptr(leaf, slot, 3054 struct btrfs_extent_ref_v0); 3055 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0); 3056 break; 3057 } 3058 return 0; 3059 } 3060 #endif 3061 3062 /* 3063 * helper to add a tree block to the list. 3064 * the major work is getting the generation and level of the block 3065 */ 3066 static int add_tree_block(struct reloc_control *rc, 3067 struct btrfs_key *extent_key, 3068 struct btrfs_path *path, 3069 struct rb_root *blocks) 3070 { 3071 struct extent_buffer *eb; 3072 struct btrfs_extent_item *ei; 3073 struct btrfs_tree_block_info *bi; 3074 struct tree_block *block; 3075 struct rb_node *rb_node; 3076 u32 item_size; 3077 int level = -1; 3078 int generation; 3079 3080 eb = path->nodes[0]; 3081 item_size = btrfs_item_size_nr(eb, path->slots[0]); 3082 3083 if (item_size >= sizeof(*ei) + sizeof(*bi)) { 3084 ei = btrfs_item_ptr(eb, path->slots[0], 3085 struct btrfs_extent_item); 3086 bi = (struct btrfs_tree_block_info *)(ei + 1); 3087 generation = btrfs_extent_generation(eb, ei); 3088 level = btrfs_tree_block_level(eb, bi); 3089 } else { 3090 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 3091 u64 ref_owner; 3092 int ret; 3093 3094 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0)); 3095 ret = get_ref_objectid_v0(rc, path, extent_key, 3096 &ref_owner, NULL); 3097 if (ret < 0) 3098 return ret; 3099 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL); 3100 level = (int)ref_owner; 3101 /* FIXME: get real generation */ 3102 generation = 0; 3103 #else 3104 BUG(); 3105 #endif 3106 } 3107 3108 btrfs_release_path(rc->extent_root, path); 3109 3110 BUG_ON(level == -1); 3111 3112 block = kmalloc(sizeof(*block), GFP_NOFS); 3113 if (!block) 3114 return -ENOMEM; 3115 3116 block->bytenr = extent_key->objectid; 3117 block->key.objectid = extent_key->offset; 3118 block->key.offset = generation; 3119 block->level = level; 3120 block->key_ready = 0; 3121 3122 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node); 3123 BUG_ON(rb_node); 3124 3125 return 0; 3126 } 3127 3128 /* 3129 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY 3130 */ 3131 static int __add_tree_block(struct reloc_control *rc, 3132 u64 bytenr, u32 blocksize, 3133 struct rb_root *blocks) 3134 { 3135 struct btrfs_path *path; 3136 struct btrfs_key key; 3137 int ret; 3138 3139 if (tree_block_processed(bytenr, blocksize, rc)) 3140 return 0; 3141 3142 if (tree_search(blocks, bytenr)) 3143 return 0; 3144 3145 path = btrfs_alloc_path(); 3146 if (!path) 3147 return -ENOMEM; 3148 3149 key.objectid = bytenr; 3150 key.type = BTRFS_EXTENT_ITEM_KEY; 3151 key.offset = blocksize; 3152 3153 path->search_commit_root = 1; 3154 path->skip_locking = 1; 3155 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0); 3156 if (ret < 0) 3157 goto out; 3158 BUG_ON(ret); 3159 3160 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 3161 ret = add_tree_block(rc, &key, path, blocks); 3162 out: 3163 btrfs_free_path(path); 3164 return ret; 3165 } 3166 3167 /* 3168 * helper to check if the block use full backrefs for pointers in it 3169 */ 3170 static int block_use_full_backref(struct reloc_control *rc, 3171 struct extent_buffer *eb) 3172 { 3173 u64 flags; 3174 int ret; 3175 3176 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) || 3177 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV) 3178 return 1; 3179 3180 ret = btrfs_lookup_extent_info(NULL, rc->extent_root, 3181 eb->start, eb->len, NULL, &flags); 3182 BUG_ON(ret); 3183 3184 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) 3185 ret = 1; 3186 else 3187 ret = 0; 3188 return ret; 3189 } 3190 3191 static int delete_block_group_cache(struct btrfs_fs_info *fs_info, 3192 struct inode *inode, u64 ino) 3193 { 3194 struct btrfs_key key; 3195 struct btrfs_path *path; 3196 struct btrfs_root *root = fs_info->tree_root; 3197 struct btrfs_trans_handle *trans; 3198 unsigned long nr; 3199 int ret = 0; 3200 3201 if (inode) 3202 goto truncate; 3203 3204 key.objectid = ino; 3205 key.type = BTRFS_INODE_ITEM_KEY; 3206 key.offset = 0; 3207 3208 inode = btrfs_iget(fs_info->sb, &key, root, NULL); 3209 if (!inode || IS_ERR(inode) || is_bad_inode(inode)) { 3210 if (inode && !IS_ERR(inode)) 3211 iput(inode); 3212 return -ENOENT; 3213 } 3214 3215 truncate: 3216 path = btrfs_alloc_path(); 3217 if (!path) { 3218 ret = -ENOMEM; 3219 goto out; 3220 } 3221 3222 trans = btrfs_join_transaction(root, 0); 3223 if (IS_ERR(trans)) { 3224 btrfs_free_path(path); 3225 goto out; 3226 } 3227 3228 ret = btrfs_truncate_free_space_cache(root, trans, path, inode); 3229 3230 btrfs_free_path(path); 3231 nr = trans->blocks_used; 3232 btrfs_end_transaction(trans, root); 3233 btrfs_btree_balance_dirty(root, nr); 3234 out: 3235 iput(inode); 3236 return ret; 3237 } 3238 3239 /* 3240 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY 3241 * this function scans fs tree to find blocks reference the data extent 3242 */ 3243 static int find_data_references(struct reloc_control *rc, 3244 struct btrfs_key *extent_key, 3245 struct extent_buffer *leaf, 3246 struct btrfs_extent_data_ref *ref, 3247 struct rb_root *blocks) 3248 { 3249 struct btrfs_path *path; 3250 struct tree_block *block; 3251 struct btrfs_root *root; 3252 struct btrfs_file_extent_item *fi; 3253 struct rb_node *rb_node; 3254 struct btrfs_key key; 3255 u64 ref_root; 3256 u64 ref_objectid; 3257 u64 ref_offset; 3258 u32 ref_count; 3259 u32 nritems; 3260 int err = 0; 3261 int added = 0; 3262 int counted; 3263 int ret; 3264 3265 ref_root = btrfs_extent_data_ref_root(leaf, ref); 3266 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref); 3267 ref_offset = btrfs_extent_data_ref_offset(leaf, ref); 3268 ref_count = btrfs_extent_data_ref_count(leaf, ref); 3269 3270 /* 3271 * This is an extent belonging to the free space cache, lets just delete 3272 * it and redo the search. 3273 */ 3274 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) { 3275 ret = delete_block_group_cache(rc->extent_root->fs_info, 3276 NULL, ref_objectid); 3277 if (ret != -ENOENT) 3278 return ret; 3279 ret = 0; 3280 } 3281 3282 path = btrfs_alloc_path(); 3283 if (!path) 3284 return -ENOMEM; 3285 3286 root = read_fs_root(rc->extent_root->fs_info, ref_root); 3287 if (IS_ERR(root)) { 3288 err = PTR_ERR(root); 3289 goto out; 3290 } 3291 3292 key.objectid = ref_objectid; 3293 key.offset = ref_offset; 3294 key.type = BTRFS_EXTENT_DATA_KEY; 3295 3296 path->search_commit_root = 1; 3297 path->skip_locking = 1; 3298 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 3299 if (ret < 0) { 3300 err = ret; 3301 goto out; 3302 } 3303 3304 leaf = path->nodes[0]; 3305 nritems = btrfs_header_nritems(leaf); 3306 /* 3307 * the references in tree blocks that use full backrefs 3308 * are not counted in 3309 */ 3310 if (block_use_full_backref(rc, leaf)) 3311 counted = 0; 3312 else 3313 counted = 1; 3314 rb_node = tree_search(blocks, leaf->start); 3315 if (rb_node) { 3316 if (counted) 3317 added = 1; 3318 else 3319 path->slots[0] = nritems; 3320 } 3321 3322 while (ref_count > 0) { 3323 while (path->slots[0] >= nritems) { 3324 ret = btrfs_next_leaf(root, path); 3325 if (ret < 0) { 3326 err = ret; 3327 goto out; 3328 } 3329 if (ret > 0) { 3330 WARN_ON(1); 3331 goto out; 3332 } 3333 3334 leaf = path->nodes[0]; 3335 nritems = btrfs_header_nritems(leaf); 3336 added = 0; 3337 3338 if (block_use_full_backref(rc, leaf)) 3339 counted = 0; 3340 else 3341 counted = 1; 3342 rb_node = tree_search(blocks, leaf->start); 3343 if (rb_node) { 3344 if (counted) 3345 added = 1; 3346 else 3347 path->slots[0] = nritems; 3348 } 3349 } 3350 3351 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 3352 if (key.objectid != ref_objectid || 3353 key.type != BTRFS_EXTENT_DATA_KEY) { 3354 WARN_ON(1); 3355 break; 3356 } 3357 3358 fi = btrfs_item_ptr(leaf, path->slots[0], 3359 struct btrfs_file_extent_item); 3360 3361 if (btrfs_file_extent_type(leaf, fi) == 3362 BTRFS_FILE_EXTENT_INLINE) 3363 goto next; 3364 3365 if (btrfs_file_extent_disk_bytenr(leaf, fi) != 3366 extent_key->objectid) 3367 goto next; 3368 3369 key.offset -= btrfs_file_extent_offset(leaf, fi); 3370 if (key.offset != ref_offset) 3371 goto next; 3372 3373 if (counted) 3374 ref_count--; 3375 if (added) 3376 goto next; 3377 3378 if (!tree_block_processed(leaf->start, leaf->len, rc)) { 3379 block = kmalloc(sizeof(*block), GFP_NOFS); 3380 if (!block) { 3381 err = -ENOMEM; 3382 break; 3383 } 3384 block->bytenr = leaf->start; 3385 btrfs_item_key_to_cpu(leaf, &block->key, 0); 3386 block->level = 0; 3387 block->key_ready = 1; 3388 rb_node = tree_insert(blocks, block->bytenr, 3389 &block->rb_node); 3390 BUG_ON(rb_node); 3391 } 3392 if (counted) 3393 added = 1; 3394 else 3395 path->slots[0] = nritems; 3396 next: 3397 path->slots[0]++; 3398 3399 } 3400 out: 3401 btrfs_free_path(path); 3402 return err; 3403 } 3404 3405 /* 3406 * hepler to find all tree blocks that reference a given data extent 3407 */ 3408 static noinline_for_stack 3409 int add_data_references(struct reloc_control *rc, 3410 struct btrfs_key *extent_key, 3411 struct btrfs_path *path, 3412 struct rb_root *blocks) 3413 { 3414 struct btrfs_key key; 3415 struct extent_buffer *eb; 3416 struct btrfs_extent_data_ref *dref; 3417 struct btrfs_extent_inline_ref *iref; 3418 unsigned long ptr; 3419 unsigned long end; 3420 u32 blocksize = btrfs_level_size(rc->extent_root, 0); 3421 int ret; 3422 int err = 0; 3423 3424 eb = path->nodes[0]; 3425 ptr = btrfs_item_ptr_offset(eb, path->slots[0]); 3426 end = ptr + btrfs_item_size_nr(eb, path->slots[0]); 3427 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 3428 if (ptr + sizeof(struct btrfs_extent_item_v0) == end) 3429 ptr = end; 3430 else 3431 #endif 3432 ptr += sizeof(struct btrfs_extent_item); 3433 3434 while (ptr < end) { 3435 iref = (struct btrfs_extent_inline_ref *)ptr; 3436 key.type = btrfs_extent_inline_ref_type(eb, iref); 3437 if (key.type == BTRFS_SHARED_DATA_REF_KEY) { 3438 key.offset = btrfs_extent_inline_ref_offset(eb, iref); 3439 ret = __add_tree_block(rc, key.offset, blocksize, 3440 blocks); 3441 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { 3442 dref = (struct btrfs_extent_data_ref *)(&iref->offset); 3443 ret = find_data_references(rc, extent_key, 3444 eb, dref, blocks); 3445 } else { 3446 BUG(); 3447 } 3448 ptr += btrfs_extent_inline_ref_size(key.type); 3449 } 3450 WARN_ON(ptr > end); 3451 3452 while (1) { 3453 cond_resched(); 3454 eb = path->nodes[0]; 3455 if (path->slots[0] >= btrfs_header_nritems(eb)) { 3456 ret = btrfs_next_leaf(rc->extent_root, path); 3457 if (ret < 0) { 3458 err = ret; 3459 break; 3460 } 3461 if (ret > 0) 3462 break; 3463 eb = path->nodes[0]; 3464 } 3465 3466 btrfs_item_key_to_cpu(eb, &key, path->slots[0]); 3467 if (key.objectid != extent_key->objectid) 3468 break; 3469 3470 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 3471 if (key.type == BTRFS_SHARED_DATA_REF_KEY || 3472 key.type == BTRFS_EXTENT_REF_V0_KEY) { 3473 #else 3474 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY); 3475 if (key.type == BTRFS_SHARED_DATA_REF_KEY) { 3476 #endif 3477 ret = __add_tree_block(rc, key.offset, blocksize, 3478 blocks); 3479 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { 3480 dref = btrfs_item_ptr(eb, path->slots[0], 3481 struct btrfs_extent_data_ref); 3482 ret = find_data_references(rc, extent_key, 3483 eb, dref, blocks); 3484 } else { 3485 ret = 0; 3486 } 3487 if (ret) { 3488 err = ret; 3489 break; 3490 } 3491 path->slots[0]++; 3492 } 3493 btrfs_release_path(rc->extent_root, path); 3494 if (err) 3495 free_block_list(blocks); 3496 return err; 3497 } 3498 3499 /* 3500 * hepler to find next unprocessed extent 3501 */ 3502 static noinline_for_stack 3503 int find_next_extent(struct btrfs_trans_handle *trans, 3504 struct reloc_control *rc, struct btrfs_path *path, 3505 struct btrfs_key *extent_key) 3506 { 3507 struct btrfs_key key; 3508 struct extent_buffer *leaf; 3509 u64 start, end, last; 3510 int ret; 3511 3512 last = rc->block_group->key.objectid + rc->block_group->key.offset; 3513 while (1) { 3514 cond_resched(); 3515 if (rc->search_start >= last) { 3516 ret = 1; 3517 break; 3518 } 3519 3520 key.objectid = rc->search_start; 3521 key.type = BTRFS_EXTENT_ITEM_KEY; 3522 key.offset = 0; 3523 3524 path->search_commit_root = 1; 3525 path->skip_locking = 1; 3526 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 3527 0, 0); 3528 if (ret < 0) 3529 break; 3530 next: 3531 leaf = path->nodes[0]; 3532 if (path->slots[0] >= btrfs_header_nritems(leaf)) { 3533 ret = btrfs_next_leaf(rc->extent_root, path); 3534 if (ret != 0) 3535 break; 3536 leaf = path->nodes[0]; 3537 } 3538 3539 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 3540 if (key.objectid >= last) { 3541 ret = 1; 3542 break; 3543 } 3544 3545 if (key.type != BTRFS_EXTENT_ITEM_KEY || 3546 key.objectid + key.offset <= rc->search_start) { 3547 path->slots[0]++; 3548 goto next; 3549 } 3550 3551 ret = find_first_extent_bit(&rc->processed_blocks, 3552 key.objectid, &start, &end, 3553 EXTENT_DIRTY); 3554 3555 if (ret == 0 && start <= key.objectid) { 3556 btrfs_release_path(rc->extent_root, path); 3557 rc->search_start = end + 1; 3558 } else { 3559 rc->search_start = key.objectid + key.offset; 3560 memcpy(extent_key, &key, sizeof(key)); 3561 return 0; 3562 } 3563 } 3564 btrfs_release_path(rc->extent_root, path); 3565 return ret; 3566 } 3567 3568 static void set_reloc_control(struct reloc_control *rc) 3569 { 3570 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; 3571 mutex_lock(&fs_info->trans_mutex); 3572 fs_info->reloc_ctl = rc; 3573 mutex_unlock(&fs_info->trans_mutex); 3574 } 3575 3576 static void unset_reloc_control(struct reloc_control *rc) 3577 { 3578 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; 3579 mutex_lock(&fs_info->trans_mutex); 3580 fs_info->reloc_ctl = NULL; 3581 mutex_unlock(&fs_info->trans_mutex); 3582 } 3583 3584 static int check_extent_flags(u64 flags) 3585 { 3586 if ((flags & BTRFS_EXTENT_FLAG_DATA) && 3587 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) 3588 return 1; 3589 if (!(flags & BTRFS_EXTENT_FLAG_DATA) && 3590 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) 3591 return 1; 3592 if ((flags & BTRFS_EXTENT_FLAG_DATA) && 3593 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) 3594 return 1; 3595 return 0; 3596 } 3597 3598 static noinline_for_stack 3599 int prepare_to_relocate(struct reloc_control *rc) 3600 { 3601 struct btrfs_trans_handle *trans; 3602 int ret; 3603 3604 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root); 3605 if (!rc->block_rsv) 3606 return -ENOMEM; 3607 3608 /* 3609 * reserve some space for creating reloc trees. 3610 * btrfs_init_reloc_root will use them when there 3611 * is no reservation in transaction handle. 3612 */ 3613 ret = btrfs_block_rsv_add(NULL, rc->extent_root, rc->block_rsv, 3614 rc->extent_root->nodesize * 256); 3615 if (ret) 3616 return ret; 3617 3618 rc->block_rsv->refill_used = 1; 3619 btrfs_add_durable_block_rsv(rc->extent_root->fs_info, rc->block_rsv); 3620 3621 memset(&rc->cluster, 0, sizeof(rc->cluster)); 3622 rc->search_start = rc->block_group->key.objectid; 3623 rc->extents_found = 0; 3624 rc->nodes_relocated = 0; 3625 rc->merging_rsv_size = 0; 3626 3627 rc->create_reloc_tree = 1; 3628 set_reloc_control(rc); 3629 3630 trans = btrfs_join_transaction(rc->extent_root, 1); 3631 btrfs_commit_transaction(trans, rc->extent_root); 3632 return 0; 3633 } 3634 3635 static noinline_for_stack int relocate_block_group(struct reloc_control *rc) 3636 { 3637 struct rb_root blocks = RB_ROOT; 3638 struct btrfs_key key; 3639 struct btrfs_trans_handle *trans = NULL; 3640 struct btrfs_path *path; 3641 struct btrfs_extent_item *ei; 3642 unsigned long nr; 3643 u64 flags; 3644 u32 item_size; 3645 int ret; 3646 int err = 0; 3647 3648 path = btrfs_alloc_path(); 3649 if (!path) 3650 return -ENOMEM; 3651 3652 ret = prepare_to_relocate(rc); 3653 if (ret) { 3654 err = ret; 3655 goto out_free; 3656 } 3657 3658 while (1) { 3659 trans = btrfs_start_transaction(rc->extent_root, 0); 3660 3661 if (update_backref_cache(trans, &rc->backref_cache)) { 3662 btrfs_end_transaction(trans, rc->extent_root); 3663 continue; 3664 } 3665 3666 ret = find_next_extent(trans, rc, path, &key); 3667 if (ret < 0) 3668 err = ret; 3669 if (ret != 0) 3670 break; 3671 3672 rc->extents_found++; 3673 3674 ei = btrfs_item_ptr(path->nodes[0], path->slots[0], 3675 struct btrfs_extent_item); 3676 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]); 3677 if (item_size >= sizeof(*ei)) { 3678 flags = btrfs_extent_flags(path->nodes[0], ei); 3679 ret = check_extent_flags(flags); 3680 BUG_ON(ret); 3681 3682 } else { 3683 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 3684 u64 ref_owner; 3685 int path_change = 0; 3686 3687 BUG_ON(item_size != 3688 sizeof(struct btrfs_extent_item_v0)); 3689 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner, 3690 &path_change); 3691 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID) 3692 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK; 3693 else 3694 flags = BTRFS_EXTENT_FLAG_DATA; 3695 3696 if (path_change) { 3697 btrfs_release_path(rc->extent_root, path); 3698 3699 path->search_commit_root = 1; 3700 path->skip_locking = 1; 3701 ret = btrfs_search_slot(NULL, rc->extent_root, 3702 &key, path, 0, 0); 3703 if (ret < 0) { 3704 err = ret; 3705 break; 3706 } 3707 BUG_ON(ret > 0); 3708 } 3709 #else 3710 BUG(); 3711 #endif 3712 } 3713 3714 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { 3715 ret = add_tree_block(rc, &key, path, &blocks); 3716 } else if (rc->stage == UPDATE_DATA_PTRS && 3717 (flags & BTRFS_EXTENT_FLAG_DATA)) { 3718 ret = add_data_references(rc, &key, path, &blocks); 3719 } else { 3720 btrfs_release_path(rc->extent_root, path); 3721 ret = 0; 3722 } 3723 if (ret < 0) { 3724 err = ret; 3725 break; 3726 } 3727 3728 if (!RB_EMPTY_ROOT(&blocks)) { 3729 ret = relocate_tree_blocks(trans, rc, &blocks); 3730 if (ret < 0) { 3731 if (ret != -EAGAIN) { 3732 err = ret; 3733 break; 3734 } 3735 rc->extents_found--; 3736 rc->search_start = key.objectid; 3737 } 3738 } 3739 3740 ret = btrfs_block_rsv_check(trans, rc->extent_root, 3741 rc->block_rsv, 0, 5); 3742 if (ret < 0) { 3743 if (ret != -EAGAIN) { 3744 err = ret; 3745 WARN_ON(1); 3746 break; 3747 } 3748 rc->commit_transaction = 1; 3749 } 3750 3751 if (rc->commit_transaction) { 3752 rc->commit_transaction = 0; 3753 ret = btrfs_commit_transaction(trans, rc->extent_root); 3754 BUG_ON(ret); 3755 } else { 3756 nr = trans->blocks_used; 3757 btrfs_end_transaction_throttle(trans, rc->extent_root); 3758 btrfs_btree_balance_dirty(rc->extent_root, nr); 3759 } 3760 trans = NULL; 3761 3762 if (rc->stage == MOVE_DATA_EXTENTS && 3763 (flags & BTRFS_EXTENT_FLAG_DATA)) { 3764 rc->found_file_extent = 1; 3765 ret = relocate_data_extent(rc->data_inode, 3766 &key, &rc->cluster); 3767 if (ret < 0) { 3768 err = ret; 3769 break; 3770 } 3771 } 3772 } 3773 3774 btrfs_release_path(rc->extent_root, path); 3775 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY, 3776 GFP_NOFS); 3777 3778 if (trans) { 3779 nr = trans->blocks_used; 3780 btrfs_end_transaction_throttle(trans, rc->extent_root); 3781 btrfs_btree_balance_dirty(rc->extent_root, nr); 3782 } 3783 3784 if (!err) { 3785 ret = relocate_file_extent_cluster(rc->data_inode, 3786 &rc->cluster); 3787 if (ret < 0) 3788 err = ret; 3789 } 3790 3791 rc->create_reloc_tree = 0; 3792 set_reloc_control(rc); 3793 3794 backref_cache_cleanup(&rc->backref_cache); 3795 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1); 3796 3797 err = prepare_to_merge(rc, err); 3798 3799 merge_reloc_roots(rc); 3800 3801 rc->merge_reloc_tree = 0; 3802 unset_reloc_control(rc); 3803 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1); 3804 3805 /* get rid of pinned extents */ 3806 trans = btrfs_join_transaction(rc->extent_root, 1); 3807 btrfs_commit_transaction(trans, rc->extent_root); 3808 out_free: 3809 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv); 3810 btrfs_free_path(path); 3811 return err; 3812 } 3813 3814 static int __insert_orphan_inode(struct btrfs_trans_handle *trans, 3815 struct btrfs_root *root, u64 objectid) 3816 { 3817 struct btrfs_path *path; 3818 struct btrfs_inode_item *item; 3819 struct extent_buffer *leaf; 3820 int ret; 3821 3822 path = btrfs_alloc_path(); 3823 if (!path) 3824 return -ENOMEM; 3825 3826 ret = btrfs_insert_empty_inode(trans, root, path, objectid); 3827 if (ret) 3828 goto out; 3829 3830 leaf = path->nodes[0]; 3831 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item); 3832 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item)); 3833 btrfs_set_inode_generation(leaf, item, 1); 3834 btrfs_set_inode_size(leaf, item, 0); 3835 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600); 3836 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS | 3837 BTRFS_INODE_PREALLOC); 3838 btrfs_mark_buffer_dirty(leaf); 3839 btrfs_release_path(root, path); 3840 out: 3841 btrfs_free_path(path); 3842 return ret; 3843 } 3844 3845 /* 3846 * helper to create inode for data relocation. 3847 * the inode is in data relocation tree and its link count is 0 3848 */ 3849 static noinline_for_stack 3850 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info, 3851 struct btrfs_block_group_cache *group) 3852 { 3853 struct inode *inode = NULL; 3854 struct btrfs_trans_handle *trans; 3855 struct btrfs_root *root; 3856 struct btrfs_key key; 3857 unsigned long nr; 3858 u64 objectid = BTRFS_FIRST_FREE_OBJECTID; 3859 int err = 0; 3860 3861 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID); 3862 if (IS_ERR(root)) 3863 return ERR_CAST(root); 3864 3865 trans = btrfs_start_transaction(root, 6); 3866 if (IS_ERR(trans)) 3867 return ERR_CAST(trans); 3868 3869 err = btrfs_find_free_objectid(trans, root, objectid, &objectid); 3870 if (err) 3871 goto out; 3872 3873 err = __insert_orphan_inode(trans, root, objectid); 3874 BUG_ON(err); 3875 3876 key.objectid = objectid; 3877 key.type = BTRFS_INODE_ITEM_KEY; 3878 key.offset = 0; 3879 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL); 3880 BUG_ON(IS_ERR(inode) || is_bad_inode(inode)); 3881 BTRFS_I(inode)->index_cnt = group->key.objectid; 3882 3883 err = btrfs_orphan_add(trans, inode); 3884 out: 3885 nr = trans->blocks_used; 3886 btrfs_end_transaction(trans, root); 3887 btrfs_btree_balance_dirty(root, nr); 3888 if (err) { 3889 if (inode) 3890 iput(inode); 3891 inode = ERR_PTR(err); 3892 } 3893 return inode; 3894 } 3895 3896 static struct reloc_control *alloc_reloc_control(void) 3897 { 3898 struct reloc_control *rc; 3899 3900 rc = kzalloc(sizeof(*rc), GFP_NOFS); 3901 if (!rc) 3902 return NULL; 3903 3904 INIT_LIST_HEAD(&rc->reloc_roots); 3905 backref_cache_init(&rc->backref_cache); 3906 mapping_tree_init(&rc->reloc_root_tree); 3907 extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS); 3908 return rc; 3909 } 3910 3911 /* 3912 * function to relocate all extents in a block group. 3913 */ 3914 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start) 3915 { 3916 struct btrfs_fs_info *fs_info = extent_root->fs_info; 3917 struct reloc_control *rc; 3918 struct inode *inode; 3919 struct btrfs_path *path; 3920 int ret; 3921 int rw = 0; 3922 int err = 0; 3923 3924 rc = alloc_reloc_control(); 3925 if (!rc) 3926 return -ENOMEM; 3927 3928 rc->extent_root = extent_root; 3929 3930 rc->block_group = btrfs_lookup_block_group(fs_info, group_start); 3931 BUG_ON(!rc->block_group); 3932 3933 if (!rc->block_group->ro) { 3934 ret = btrfs_set_block_group_ro(extent_root, rc->block_group); 3935 if (ret) { 3936 err = ret; 3937 goto out; 3938 } 3939 rw = 1; 3940 } 3941 3942 path = btrfs_alloc_path(); 3943 if (!path) { 3944 err = -ENOMEM; 3945 goto out; 3946 } 3947 3948 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group, 3949 path); 3950 btrfs_free_path(path); 3951 3952 if (!IS_ERR(inode)) 3953 ret = delete_block_group_cache(fs_info, inode, 0); 3954 else 3955 ret = PTR_ERR(inode); 3956 3957 if (ret && ret != -ENOENT) { 3958 err = ret; 3959 goto out; 3960 } 3961 3962 rc->data_inode = create_reloc_inode(fs_info, rc->block_group); 3963 if (IS_ERR(rc->data_inode)) { 3964 err = PTR_ERR(rc->data_inode); 3965 rc->data_inode = NULL; 3966 goto out; 3967 } 3968 3969 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n", 3970 (unsigned long long)rc->block_group->key.objectid, 3971 (unsigned long long)rc->block_group->flags); 3972 3973 btrfs_start_delalloc_inodes(fs_info->tree_root, 0); 3974 btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0); 3975 3976 while (1) { 3977 mutex_lock(&fs_info->cleaner_mutex); 3978 3979 btrfs_clean_old_snapshots(fs_info->tree_root); 3980 ret = relocate_block_group(rc); 3981 3982 mutex_unlock(&fs_info->cleaner_mutex); 3983 if (ret < 0) { 3984 err = ret; 3985 goto out; 3986 } 3987 3988 if (rc->extents_found == 0) 3989 break; 3990 3991 printk(KERN_INFO "btrfs: found %llu extents\n", 3992 (unsigned long long)rc->extents_found); 3993 3994 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) { 3995 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1); 3996 invalidate_mapping_pages(rc->data_inode->i_mapping, 3997 0, -1); 3998 rc->stage = UPDATE_DATA_PTRS; 3999 } 4000 } 4001 4002 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping, 4003 rc->block_group->key.objectid, 4004 rc->block_group->key.objectid + 4005 rc->block_group->key.offset - 1); 4006 4007 WARN_ON(rc->block_group->pinned > 0); 4008 WARN_ON(rc->block_group->reserved > 0); 4009 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0); 4010 out: 4011 if (err && rw) 4012 btrfs_set_block_group_rw(extent_root, rc->block_group); 4013 iput(rc->data_inode); 4014 btrfs_put_block_group(rc->block_group); 4015 kfree(rc); 4016 return err; 4017 } 4018 4019 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root) 4020 { 4021 struct btrfs_trans_handle *trans; 4022 int ret; 4023 4024 trans = btrfs_start_transaction(root->fs_info->tree_root, 0); 4025 4026 memset(&root->root_item.drop_progress, 0, 4027 sizeof(root->root_item.drop_progress)); 4028 root->root_item.drop_level = 0; 4029 btrfs_set_root_refs(&root->root_item, 0); 4030 ret = btrfs_update_root(trans, root->fs_info->tree_root, 4031 &root->root_key, &root->root_item); 4032 BUG_ON(ret); 4033 4034 ret = btrfs_end_transaction(trans, root->fs_info->tree_root); 4035 BUG_ON(ret); 4036 return 0; 4037 } 4038 4039 /* 4040 * recover relocation interrupted by system crash. 4041 * 4042 * this function resumes merging reloc trees with corresponding fs trees. 4043 * this is important for keeping the sharing of tree blocks 4044 */ 4045 int btrfs_recover_relocation(struct btrfs_root *root) 4046 { 4047 LIST_HEAD(reloc_roots); 4048 struct btrfs_key key; 4049 struct btrfs_root *fs_root; 4050 struct btrfs_root *reloc_root; 4051 struct btrfs_path *path; 4052 struct extent_buffer *leaf; 4053 struct reloc_control *rc = NULL; 4054 struct btrfs_trans_handle *trans; 4055 int ret; 4056 int err = 0; 4057 4058 path = btrfs_alloc_path(); 4059 if (!path) 4060 return -ENOMEM; 4061 4062 key.objectid = BTRFS_TREE_RELOC_OBJECTID; 4063 key.type = BTRFS_ROOT_ITEM_KEY; 4064 key.offset = (u64)-1; 4065 4066 while (1) { 4067 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key, 4068 path, 0, 0); 4069 if (ret < 0) { 4070 err = ret; 4071 goto out; 4072 } 4073 if (ret > 0) { 4074 if (path->slots[0] == 0) 4075 break; 4076 path->slots[0]--; 4077 } 4078 leaf = path->nodes[0]; 4079 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 4080 btrfs_release_path(root->fs_info->tree_root, path); 4081 4082 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID || 4083 key.type != BTRFS_ROOT_ITEM_KEY) 4084 break; 4085 4086 reloc_root = btrfs_read_fs_root_no_radix(root, &key); 4087 if (IS_ERR(reloc_root)) { 4088 err = PTR_ERR(reloc_root); 4089 goto out; 4090 } 4091 4092 list_add(&reloc_root->root_list, &reloc_roots); 4093 4094 if (btrfs_root_refs(&reloc_root->root_item) > 0) { 4095 fs_root = read_fs_root(root->fs_info, 4096 reloc_root->root_key.offset); 4097 if (IS_ERR(fs_root)) { 4098 ret = PTR_ERR(fs_root); 4099 if (ret != -ENOENT) { 4100 err = ret; 4101 goto out; 4102 } 4103 mark_garbage_root(reloc_root); 4104 } 4105 } 4106 4107 if (key.offset == 0) 4108 break; 4109 4110 key.offset--; 4111 } 4112 btrfs_release_path(root->fs_info->tree_root, path); 4113 4114 if (list_empty(&reloc_roots)) 4115 goto out; 4116 4117 rc = alloc_reloc_control(); 4118 if (!rc) { 4119 err = -ENOMEM; 4120 goto out; 4121 } 4122 4123 rc->extent_root = root->fs_info->extent_root; 4124 4125 set_reloc_control(rc); 4126 4127 trans = btrfs_join_transaction(rc->extent_root, 1); 4128 4129 rc->merge_reloc_tree = 1; 4130 4131 while (!list_empty(&reloc_roots)) { 4132 reloc_root = list_entry(reloc_roots.next, 4133 struct btrfs_root, root_list); 4134 list_del(&reloc_root->root_list); 4135 4136 if (btrfs_root_refs(&reloc_root->root_item) == 0) { 4137 list_add_tail(&reloc_root->root_list, 4138 &rc->reloc_roots); 4139 continue; 4140 } 4141 4142 fs_root = read_fs_root(root->fs_info, 4143 reloc_root->root_key.offset); 4144 BUG_ON(IS_ERR(fs_root)); 4145 4146 __add_reloc_root(reloc_root); 4147 fs_root->reloc_root = reloc_root; 4148 } 4149 4150 btrfs_commit_transaction(trans, rc->extent_root); 4151 4152 merge_reloc_roots(rc); 4153 4154 unset_reloc_control(rc); 4155 4156 trans = btrfs_join_transaction(rc->extent_root, 1); 4157 btrfs_commit_transaction(trans, rc->extent_root); 4158 out: 4159 kfree(rc); 4160 while (!list_empty(&reloc_roots)) { 4161 reloc_root = list_entry(reloc_roots.next, 4162 struct btrfs_root, root_list); 4163 list_del(&reloc_root->root_list); 4164 free_extent_buffer(reloc_root->node); 4165 free_extent_buffer(reloc_root->commit_root); 4166 kfree(reloc_root); 4167 } 4168 btrfs_free_path(path); 4169 4170 if (err == 0) { 4171 /* cleanup orphan inode in data relocation tree */ 4172 fs_root = read_fs_root(root->fs_info, 4173 BTRFS_DATA_RELOC_TREE_OBJECTID); 4174 if (IS_ERR(fs_root)) 4175 err = PTR_ERR(fs_root); 4176 else 4177 btrfs_orphan_cleanup(fs_root); 4178 } 4179 return err; 4180 } 4181 4182 /* 4183 * helper to add ordered checksum for data relocation. 4184 * 4185 * cloning checksum properly handles the nodatasum extents. 4186 * it also saves CPU time to re-calculate the checksum. 4187 */ 4188 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len) 4189 { 4190 struct btrfs_ordered_sum *sums; 4191 struct btrfs_sector_sum *sector_sum; 4192 struct btrfs_ordered_extent *ordered; 4193 struct btrfs_root *root = BTRFS_I(inode)->root; 4194 size_t offset; 4195 int ret; 4196 u64 disk_bytenr; 4197 LIST_HEAD(list); 4198 4199 ordered = btrfs_lookup_ordered_extent(inode, file_pos); 4200 BUG_ON(ordered->file_offset != file_pos || ordered->len != len); 4201 4202 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt; 4203 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr, 4204 disk_bytenr + len - 1, &list); 4205 4206 while (!list_empty(&list)) { 4207 sums = list_entry(list.next, struct btrfs_ordered_sum, list); 4208 list_del_init(&sums->list); 4209 4210 sector_sum = sums->sums; 4211 sums->bytenr = ordered->start; 4212 4213 offset = 0; 4214 while (offset < sums->len) { 4215 sector_sum->bytenr += ordered->start - disk_bytenr; 4216 sector_sum++; 4217 offset += root->sectorsize; 4218 } 4219 4220 btrfs_add_ordered_sum(inode, ordered, sums); 4221 } 4222 btrfs_put_ordered_extent(ordered); 4223 return ret; 4224 } 4225 4226 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans, 4227 struct btrfs_root *root, struct extent_buffer *buf, 4228 struct extent_buffer *cow) 4229 { 4230 struct reloc_control *rc; 4231 struct backref_node *node; 4232 int first_cow = 0; 4233 int level; 4234 int ret; 4235 4236 rc = root->fs_info->reloc_ctl; 4237 if (!rc) 4238 return; 4239 4240 BUG_ON(rc->stage == UPDATE_DATA_PTRS && 4241 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID); 4242 4243 level = btrfs_header_level(buf); 4244 if (btrfs_header_generation(buf) <= 4245 btrfs_root_last_snapshot(&root->root_item)) 4246 first_cow = 1; 4247 4248 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID && 4249 rc->create_reloc_tree) { 4250 WARN_ON(!first_cow && level == 0); 4251 4252 node = rc->backref_cache.path[level]; 4253 BUG_ON(node->bytenr != buf->start && 4254 node->new_bytenr != buf->start); 4255 4256 drop_node_buffer(node); 4257 extent_buffer_get(cow); 4258 node->eb = cow; 4259 node->new_bytenr = cow->start; 4260 4261 if (!node->pending) { 4262 list_move_tail(&node->list, 4263 &rc->backref_cache.pending[level]); 4264 node->pending = 1; 4265 } 4266 4267 if (first_cow) 4268 __mark_block_processed(rc, node); 4269 4270 if (first_cow && level > 0) 4271 rc->nodes_relocated += buf->len; 4272 } 4273 4274 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) { 4275 ret = replace_file_extents(trans, rc, root, cow); 4276 BUG_ON(ret); 4277 } 4278 } 4279 4280 /* 4281 * called before creating snapshot. it calculates metadata reservation 4282 * requried for relocating tree blocks in the snapshot 4283 */ 4284 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans, 4285 struct btrfs_pending_snapshot *pending, 4286 u64 *bytes_to_reserve) 4287 { 4288 struct btrfs_root *root; 4289 struct reloc_control *rc; 4290 4291 root = pending->root; 4292 if (!root->reloc_root) 4293 return; 4294 4295 rc = root->fs_info->reloc_ctl; 4296 if (!rc->merge_reloc_tree) 4297 return; 4298 4299 root = root->reloc_root; 4300 BUG_ON(btrfs_root_refs(&root->root_item) == 0); 4301 /* 4302 * relocation is in the stage of merging trees. the space 4303 * used by merging a reloc tree is twice the size of 4304 * relocated tree nodes in the worst case. half for cowing 4305 * the reloc tree, half for cowing the fs tree. the space 4306 * used by cowing the reloc tree will be freed after the 4307 * tree is dropped. if we create snapshot, cowing the fs 4308 * tree may use more space than it frees. so we need 4309 * reserve extra space. 4310 */ 4311 *bytes_to_reserve += rc->nodes_relocated; 4312 } 4313 4314 /* 4315 * called after snapshot is created. migrate block reservation 4316 * and create reloc root for the newly created snapshot 4317 */ 4318 void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans, 4319 struct btrfs_pending_snapshot *pending) 4320 { 4321 struct btrfs_root *root = pending->root; 4322 struct btrfs_root *reloc_root; 4323 struct btrfs_root *new_root; 4324 struct reloc_control *rc; 4325 int ret; 4326 4327 if (!root->reloc_root) 4328 return; 4329 4330 rc = root->fs_info->reloc_ctl; 4331 rc->merging_rsv_size += rc->nodes_relocated; 4332 4333 if (rc->merge_reloc_tree) { 4334 ret = btrfs_block_rsv_migrate(&pending->block_rsv, 4335 rc->block_rsv, 4336 rc->nodes_relocated); 4337 BUG_ON(ret); 4338 } 4339 4340 new_root = pending->snap; 4341 reloc_root = create_reloc_root(trans, root->reloc_root, 4342 new_root->root_key.objectid); 4343 4344 __add_reloc_root(reloc_root); 4345 new_root->reloc_root = reloc_root; 4346 4347 if (rc->create_reloc_tree) { 4348 ret = clone_backref_node(trans, rc, root, reloc_root); 4349 BUG_ON(ret); 4350 } 4351 } 4352