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 33 /* 34 * backref_node, mapping_node and tree_block start with this 35 */ 36 struct tree_entry { 37 struct rb_node rb_node; 38 u64 bytenr; 39 }; 40 41 /* 42 * present a tree block in the backref cache 43 */ 44 struct backref_node { 45 struct rb_node rb_node; 46 u64 bytenr; 47 /* objectid tree block owner */ 48 u64 owner; 49 /* list of upper level blocks reference this block */ 50 struct list_head upper; 51 /* list of child blocks in the cache */ 52 struct list_head lower; 53 /* NULL if this node is not tree root */ 54 struct btrfs_root *root; 55 /* extent buffer got by COW the block */ 56 struct extent_buffer *eb; 57 /* level of tree block */ 58 unsigned int level:8; 59 /* 1 if the block is root of old snapshot */ 60 unsigned int old_root:1; 61 /* 1 if no child blocks in the cache */ 62 unsigned int lowest:1; 63 /* is the extent buffer locked */ 64 unsigned int locked:1; 65 /* has the block been processed */ 66 unsigned int processed:1; 67 /* have backrefs of this block been checked */ 68 unsigned int checked:1; 69 }; 70 71 /* 72 * present a block pointer in the backref cache 73 */ 74 struct backref_edge { 75 struct list_head list[2]; 76 struct backref_node *node[2]; 77 u64 blockptr; 78 }; 79 80 #define LOWER 0 81 #define UPPER 1 82 83 struct backref_cache { 84 /* red black tree of all backref nodes in the cache */ 85 struct rb_root rb_root; 86 /* list of backref nodes with no child block in the cache */ 87 struct list_head pending[BTRFS_MAX_LEVEL]; 88 spinlock_t lock; 89 }; 90 91 /* 92 * map address of tree root to tree 93 */ 94 struct mapping_node { 95 struct rb_node rb_node; 96 u64 bytenr; 97 void *data; 98 }; 99 100 struct mapping_tree { 101 struct rb_root rb_root; 102 spinlock_t lock; 103 }; 104 105 /* 106 * present a tree block to process 107 */ 108 struct tree_block { 109 struct rb_node rb_node; 110 u64 bytenr; 111 struct btrfs_key key; 112 unsigned int level:8; 113 unsigned int key_ready:1; 114 }; 115 116 /* inode vector */ 117 #define INODEVEC_SIZE 16 118 119 struct inodevec { 120 struct list_head list; 121 struct inode *inode[INODEVEC_SIZE]; 122 int nr; 123 }; 124 125 #define MAX_EXTENTS 128 126 127 struct file_extent_cluster { 128 u64 start; 129 u64 end; 130 u64 boundary[MAX_EXTENTS]; 131 unsigned int nr; 132 }; 133 134 struct reloc_control { 135 /* block group to relocate */ 136 struct btrfs_block_group_cache *block_group; 137 /* extent tree */ 138 struct btrfs_root *extent_root; 139 /* inode for moving data */ 140 struct inode *data_inode; 141 struct btrfs_workers workers; 142 /* tree blocks have been processed */ 143 struct extent_io_tree processed_blocks; 144 /* map start of tree root to corresponding reloc tree */ 145 struct mapping_tree reloc_root_tree; 146 /* list of reloc trees */ 147 struct list_head reloc_roots; 148 u64 search_start; 149 u64 extents_found; 150 u64 extents_skipped; 151 int stage; 152 int create_reloc_root; 153 unsigned int found_file_extent:1; 154 unsigned int found_old_snapshot:1; 155 }; 156 157 /* stages of data relocation */ 158 #define MOVE_DATA_EXTENTS 0 159 #define UPDATE_DATA_PTRS 1 160 161 /* 162 * merge reloc tree to corresponding fs tree in worker threads 163 */ 164 struct async_merge { 165 struct btrfs_work work; 166 struct reloc_control *rc; 167 struct btrfs_root *root; 168 struct completion *done; 169 atomic_t *num_pending; 170 }; 171 172 static void mapping_tree_init(struct mapping_tree *tree) 173 { 174 tree->rb_root = RB_ROOT; 175 spin_lock_init(&tree->lock); 176 } 177 178 static void backref_cache_init(struct backref_cache *cache) 179 { 180 int i; 181 cache->rb_root = RB_ROOT; 182 for (i = 0; i < BTRFS_MAX_LEVEL; i++) 183 INIT_LIST_HEAD(&cache->pending[i]); 184 spin_lock_init(&cache->lock); 185 } 186 187 static void backref_node_init(struct backref_node *node) 188 { 189 memset(node, 0, sizeof(*node)); 190 INIT_LIST_HEAD(&node->upper); 191 INIT_LIST_HEAD(&node->lower); 192 RB_CLEAR_NODE(&node->rb_node); 193 } 194 195 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr, 196 struct rb_node *node) 197 { 198 struct rb_node **p = &root->rb_node; 199 struct rb_node *parent = NULL; 200 struct tree_entry *entry; 201 202 while (*p) { 203 parent = *p; 204 entry = rb_entry(parent, struct tree_entry, rb_node); 205 206 if (bytenr < entry->bytenr) 207 p = &(*p)->rb_left; 208 else if (bytenr > entry->bytenr) 209 p = &(*p)->rb_right; 210 else 211 return parent; 212 } 213 214 rb_link_node(node, parent, p); 215 rb_insert_color(node, root); 216 return NULL; 217 } 218 219 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr) 220 { 221 struct rb_node *n = root->rb_node; 222 struct tree_entry *entry; 223 224 while (n) { 225 entry = rb_entry(n, struct tree_entry, rb_node); 226 227 if (bytenr < entry->bytenr) 228 n = n->rb_left; 229 else if (bytenr > entry->bytenr) 230 n = n->rb_right; 231 else 232 return n; 233 } 234 return NULL; 235 } 236 237 /* 238 * walk up backref nodes until reach node presents tree root 239 */ 240 static struct backref_node *walk_up_backref(struct backref_node *node, 241 struct backref_edge *edges[], 242 int *index) 243 { 244 struct backref_edge *edge; 245 int idx = *index; 246 247 while (!list_empty(&node->upper)) { 248 edge = list_entry(node->upper.next, 249 struct backref_edge, list[LOWER]); 250 edges[idx++] = edge; 251 node = edge->node[UPPER]; 252 } 253 *index = idx; 254 return node; 255 } 256 257 /* 258 * walk down backref nodes to find start of next reference path 259 */ 260 static struct backref_node *walk_down_backref(struct backref_edge *edges[], 261 int *index) 262 { 263 struct backref_edge *edge; 264 struct backref_node *lower; 265 int idx = *index; 266 267 while (idx > 0) { 268 edge = edges[idx - 1]; 269 lower = edge->node[LOWER]; 270 if (list_is_last(&edge->list[LOWER], &lower->upper)) { 271 idx--; 272 continue; 273 } 274 edge = list_entry(edge->list[LOWER].next, 275 struct backref_edge, list[LOWER]); 276 edges[idx - 1] = edge; 277 *index = idx; 278 return edge->node[UPPER]; 279 } 280 *index = 0; 281 return NULL; 282 } 283 284 static void drop_node_buffer(struct backref_node *node) 285 { 286 if (node->eb) { 287 if (node->locked) { 288 btrfs_tree_unlock(node->eb); 289 node->locked = 0; 290 } 291 free_extent_buffer(node->eb); 292 node->eb = NULL; 293 } 294 } 295 296 static void drop_backref_node(struct backref_cache *tree, 297 struct backref_node *node) 298 { 299 BUG_ON(!node->lowest); 300 BUG_ON(!list_empty(&node->upper)); 301 302 drop_node_buffer(node); 303 list_del(&node->lower); 304 305 rb_erase(&node->rb_node, &tree->rb_root); 306 kfree(node); 307 } 308 309 /* 310 * remove a backref node from the backref cache 311 */ 312 static void remove_backref_node(struct backref_cache *cache, 313 struct backref_node *node) 314 { 315 struct backref_node *upper; 316 struct backref_edge *edge; 317 318 if (!node) 319 return; 320 321 BUG_ON(!node->lowest); 322 while (!list_empty(&node->upper)) { 323 edge = list_entry(node->upper.next, struct backref_edge, 324 list[LOWER]); 325 upper = edge->node[UPPER]; 326 list_del(&edge->list[LOWER]); 327 list_del(&edge->list[UPPER]); 328 kfree(edge); 329 /* 330 * add the node to pending list if no other 331 * child block cached. 332 */ 333 if (list_empty(&upper->lower)) { 334 list_add_tail(&upper->lower, 335 &cache->pending[upper->level]); 336 upper->lowest = 1; 337 } 338 } 339 drop_backref_node(cache, node); 340 } 341 342 /* 343 * find reloc tree by address of tree root 344 */ 345 static struct btrfs_root *find_reloc_root(struct reloc_control *rc, 346 u64 bytenr) 347 { 348 struct rb_node *rb_node; 349 struct mapping_node *node; 350 struct btrfs_root *root = NULL; 351 352 spin_lock(&rc->reloc_root_tree.lock); 353 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr); 354 if (rb_node) { 355 node = rb_entry(rb_node, struct mapping_node, rb_node); 356 root = (struct btrfs_root *)node->data; 357 } 358 spin_unlock(&rc->reloc_root_tree.lock); 359 return root; 360 } 361 362 static int is_cowonly_root(u64 root_objectid) 363 { 364 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID || 365 root_objectid == BTRFS_EXTENT_TREE_OBJECTID || 366 root_objectid == BTRFS_CHUNK_TREE_OBJECTID || 367 root_objectid == BTRFS_DEV_TREE_OBJECTID || 368 root_objectid == BTRFS_TREE_LOG_OBJECTID || 369 root_objectid == BTRFS_CSUM_TREE_OBJECTID) 370 return 1; 371 return 0; 372 } 373 374 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info, 375 u64 root_objectid) 376 { 377 struct btrfs_key key; 378 379 key.objectid = root_objectid; 380 key.type = BTRFS_ROOT_ITEM_KEY; 381 if (is_cowonly_root(root_objectid)) 382 key.offset = 0; 383 else 384 key.offset = (u64)-1; 385 386 return btrfs_read_fs_root_no_name(fs_info, &key); 387 } 388 389 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 390 static noinline_for_stack 391 struct btrfs_root *find_tree_root(struct reloc_control *rc, 392 struct extent_buffer *leaf, 393 struct btrfs_extent_ref_v0 *ref0) 394 { 395 struct btrfs_root *root; 396 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0); 397 u64 generation = btrfs_ref_generation_v0(leaf, ref0); 398 399 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID); 400 401 root = read_fs_root(rc->extent_root->fs_info, root_objectid); 402 BUG_ON(IS_ERR(root)); 403 404 if (root->ref_cows && 405 generation != btrfs_root_generation(&root->root_item)) 406 return NULL; 407 408 return root; 409 } 410 #endif 411 412 static noinline_for_stack 413 int find_inline_backref(struct extent_buffer *leaf, int slot, 414 unsigned long *ptr, unsigned long *end) 415 { 416 struct btrfs_extent_item *ei; 417 struct btrfs_tree_block_info *bi; 418 u32 item_size; 419 420 item_size = btrfs_item_size_nr(leaf, slot); 421 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 422 if (item_size < sizeof(*ei)) { 423 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0)); 424 return 1; 425 } 426 #endif 427 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); 428 WARN_ON(!(btrfs_extent_flags(leaf, ei) & 429 BTRFS_EXTENT_FLAG_TREE_BLOCK)); 430 431 if (item_size <= sizeof(*ei) + sizeof(*bi)) { 432 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi)); 433 return 1; 434 } 435 436 bi = (struct btrfs_tree_block_info *)(ei + 1); 437 *ptr = (unsigned long)(bi + 1); 438 *end = (unsigned long)ei + item_size; 439 return 0; 440 } 441 442 /* 443 * build backref tree for a given tree block. root of the backref tree 444 * corresponds the tree block, leaves of the backref tree correspond 445 * roots of b-trees that reference the tree block. 446 * 447 * the basic idea of this function is check backrefs of a given block 448 * to find upper level blocks that refernece the block, and then check 449 * bakcrefs of these upper level blocks recursively. the recursion stop 450 * when tree root is reached or backrefs for the block is cached. 451 * 452 * NOTE: if we find backrefs for a block are cached, we know backrefs 453 * for all upper level blocks that directly/indirectly reference the 454 * block are also cached. 455 */ 456 static struct backref_node *build_backref_tree(struct reloc_control *rc, 457 struct backref_cache *cache, 458 struct btrfs_key *node_key, 459 int level, u64 bytenr) 460 { 461 struct btrfs_path *path1; 462 struct btrfs_path *path2; 463 struct extent_buffer *eb; 464 struct btrfs_root *root; 465 struct backref_node *cur; 466 struct backref_node *upper; 467 struct backref_node *lower; 468 struct backref_node *node = NULL; 469 struct backref_node *exist = NULL; 470 struct backref_edge *edge; 471 struct rb_node *rb_node; 472 struct btrfs_key key; 473 unsigned long end; 474 unsigned long ptr; 475 LIST_HEAD(list); 476 int ret; 477 int err = 0; 478 479 path1 = btrfs_alloc_path(); 480 path2 = btrfs_alloc_path(); 481 if (!path1 || !path2) { 482 err = -ENOMEM; 483 goto out; 484 } 485 486 node = kmalloc(sizeof(*node), GFP_NOFS); 487 if (!node) { 488 err = -ENOMEM; 489 goto out; 490 } 491 492 backref_node_init(node); 493 node->bytenr = bytenr; 494 node->owner = 0; 495 node->level = level; 496 node->lowest = 1; 497 cur = node; 498 again: 499 end = 0; 500 ptr = 0; 501 key.objectid = cur->bytenr; 502 key.type = BTRFS_EXTENT_ITEM_KEY; 503 key.offset = (u64)-1; 504 505 path1->search_commit_root = 1; 506 path1->skip_locking = 1; 507 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1, 508 0, 0); 509 if (ret < 0) { 510 err = ret; 511 goto out; 512 } 513 BUG_ON(!ret || !path1->slots[0]); 514 515 path1->slots[0]--; 516 517 WARN_ON(cur->checked); 518 if (!list_empty(&cur->upper)) { 519 /* 520 * the backref was added previously when processsing 521 * backref of type BTRFS_TREE_BLOCK_REF_KEY 522 */ 523 BUG_ON(!list_is_singular(&cur->upper)); 524 edge = list_entry(cur->upper.next, struct backref_edge, 525 list[LOWER]); 526 BUG_ON(!list_empty(&edge->list[UPPER])); 527 exist = edge->node[UPPER]; 528 /* 529 * add the upper level block to pending list if we need 530 * check its backrefs 531 */ 532 if (!exist->checked) 533 list_add_tail(&edge->list[UPPER], &list); 534 } else { 535 exist = NULL; 536 } 537 538 while (1) { 539 cond_resched(); 540 eb = path1->nodes[0]; 541 542 if (ptr >= end) { 543 if (path1->slots[0] >= btrfs_header_nritems(eb)) { 544 ret = btrfs_next_leaf(rc->extent_root, path1); 545 if (ret < 0) { 546 err = ret; 547 goto out; 548 } 549 if (ret > 0) 550 break; 551 eb = path1->nodes[0]; 552 } 553 554 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]); 555 if (key.objectid != cur->bytenr) { 556 WARN_ON(exist); 557 break; 558 } 559 560 if (key.type == BTRFS_EXTENT_ITEM_KEY) { 561 ret = find_inline_backref(eb, path1->slots[0], 562 &ptr, &end); 563 if (ret) 564 goto next; 565 } 566 } 567 568 if (ptr < end) { 569 /* update key for inline back ref */ 570 struct btrfs_extent_inline_ref *iref; 571 iref = (struct btrfs_extent_inline_ref *)ptr; 572 key.type = btrfs_extent_inline_ref_type(eb, iref); 573 key.offset = btrfs_extent_inline_ref_offset(eb, iref); 574 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY && 575 key.type != BTRFS_SHARED_BLOCK_REF_KEY); 576 } 577 578 if (exist && 579 ((key.type == BTRFS_TREE_BLOCK_REF_KEY && 580 exist->owner == key.offset) || 581 (key.type == BTRFS_SHARED_BLOCK_REF_KEY && 582 exist->bytenr == key.offset))) { 583 exist = NULL; 584 goto next; 585 } 586 587 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 588 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY || 589 key.type == BTRFS_EXTENT_REF_V0_KEY) { 590 if (key.objectid == key.offset && 591 key.type == BTRFS_EXTENT_REF_V0_KEY) { 592 struct btrfs_extent_ref_v0 *ref0; 593 ref0 = btrfs_item_ptr(eb, path1->slots[0], 594 struct btrfs_extent_ref_v0); 595 root = find_tree_root(rc, eb, ref0); 596 if (root) 597 cur->root = root; 598 else 599 cur->old_root = 1; 600 break; 601 } 602 #else 603 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY); 604 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) { 605 #endif 606 if (key.objectid == key.offset) { 607 /* 608 * only root blocks of reloc trees use 609 * backref of this type. 610 */ 611 root = find_reloc_root(rc, cur->bytenr); 612 BUG_ON(!root); 613 cur->root = root; 614 break; 615 } 616 617 edge = kzalloc(sizeof(*edge), GFP_NOFS); 618 if (!edge) { 619 err = -ENOMEM; 620 goto out; 621 } 622 rb_node = tree_search(&cache->rb_root, key.offset); 623 if (!rb_node) { 624 upper = kmalloc(sizeof(*upper), GFP_NOFS); 625 if (!upper) { 626 kfree(edge); 627 err = -ENOMEM; 628 goto out; 629 } 630 backref_node_init(upper); 631 upper->bytenr = key.offset; 632 upper->owner = 0; 633 upper->level = cur->level + 1; 634 /* 635 * backrefs for the upper level block isn't 636 * cached, add the block to pending list 637 */ 638 list_add_tail(&edge->list[UPPER], &list); 639 } else { 640 upper = rb_entry(rb_node, struct backref_node, 641 rb_node); 642 INIT_LIST_HEAD(&edge->list[UPPER]); 643 } 644 list_add(&edge->list[LOWER], &cur->upper); 645 edge->node[UPPER] = upper; 646 edge->node[LOWER] = cur; 647 648 goto next; 649 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) { 650 goto next; 651 } 652 653 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */ 654 root = read_fs_root(rc->extent_root->fs_info, key.offset); 655 if (IS_ERR(root)) { 656 err = PTR_ERR(root); 657 goto out; 658 } 659 660 if (btrfs_root_level(&root->root_item) == cur->level) { 661 /* tree root */ 662 BUG_ON(btrfs_root_bytenr(&root->root_item) != 663 cur->bytenr); 664 cur->root = root; 665 break; 666 } 667 668 level = cur->level + 1; 669 670 /* 671 * searching the tree to find upper level blocks 672 * reference the block. 673 */ 674 path2->search_commit_root = 1; 675 path2->skip_locking = 1; 676 path2->lowest_level = level; 677 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0); 678 path2->lowest_level = 0; 679 if (ret < 0) { 680 err = ret; 681 goto out; 682 } 683 if (ret > 0 && path2->slots[level] > 0) 684 path2->slots[level]--; 685 686 eb = path2->nodes[level]; 687 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) != 688 cur->bytenr); 689 690 lower = cur; 691 for (; level < BTRFS_MAX_LEVEL; level++) { 692 if (!path2->nodes[level]) { 693 BUG_ON(btrfs_root_bytenr(&root->root_item) != 694 lower->bytenr); 695 lower->root = root; 696 break; 697 } 698 699 edge = kzalloc(sizeof(*edge), GFP_NOFS); 700 if (!edge) { 701 err = -ENOMEM; 702 goto out; 703 } 704 705 eb = path2->nodes[level]; 706 rb_node = tree_search(&cache->rb_root, eb->start); 707 if (!rb_node) { 708 upper = kmalloc(sizeof(*upper), GFP_NOFS); 709 if (!upper) { 710 kfree(edge); 711 err = -ENOMEM; 712 goto out; 713 } 714 backref_node_init(upper); 715 upper->bytenr = eb->start; 716 upper->owner = btrfs_header_owner(eb); 717 upper->level = lower->level + 1; 718 719 /* 720 * if we know the block isn't shared 721 * we can void checking its backrefs. 722 */ 723 if (btrfs_block_can_be_shared(root, eb)) 724 upper->checked = 0; 725 else 726 upper->checked = 1; 727 728 /* 729 * add the block to pending list if we 730 * need check its backrefs. only block 731 * at 'cur->level + 1' is added to the 732 * tail of pending list. this guarantees 733 * we check backrefs from lower level 734 * blocks to upper level blocks. 735 */ 736 if (!upper->checked && 737 level == cur->level + 1) { 738 list_add_tail(&edge->list[UPPER], 739 &list); 740 } else 741 INIT_LIST_HEAD(&edge->list[UPPER]); 742 } else { 743 upper = rb_entry(rb_node, struct backref_node, 744 rb_node); 745 BUG_ON(!upper->checked); 746 INIT_LIST_HEAD(&edge->list[UPPER]); 747 } 748 list_add_tail(&edge->list[LOWER], &lower->upper); 749 edge->node[UPPER] = upper; 750 edge->node[LOWER] = lower; 751 752 if (rb_node) 753 break; 754 lower = upper; 755 upper = NULL; 756 } 757 btrfs_release_path(root, path2); 758 next: 759 if (ptr < end) { 760 ptr += btrfs_extent_inline_ref_size(key.type); 761 if (ptr >= end) { 762 WARN_ON(ptr > end); 763 ptr = 0; 764 end = 0; 765 } 766 } 767 if (ptr >= end) 768 path1->slots[0]++; 769 } 770 btrfs_release_path(rc->extent_root, path1); 771 772 cur->checked = 1; 773 WARN_ON(exist); 774 775 /* the pending list isn't empty, take the first block to process */ 776 if (!list_empty(&list)) { 777 edge = list_entry(list.next, struct backref_edge, list[UPPER]); 778 list_del_init(&edge->list[UPPER]); 779 cur = edge->node[UPPER]; 780 goto again; 781 } 782 783 /* 784 * everything goes well, connect backref nodes and insert backref nodes 785 * into the cache. 786 */ 787 BUG_ON(!node->checked); 788 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node); 789 BUG_ON(rb_node); 790 791 list_for_each_entry(edge, &node->upper, list[LOWER]) 792 list_add_tail(&edge->list[UPPER], &list); 793 794 while (!list_empty(&list)) { 795 edge = list_entry(list.next, struct backref_edge, list[UPPER]); 796 list_del_init(&edge->list[UPPER]); 797 upper = edge->node[UPPER]; 798 799 if (!RB_EMPTY_NODE(&upper->rb_node)) { 800 if (upper->lowest) { 801 list_del_init(&upper->lower); 802 upper->lowest = 0; 803 } 804 805 list_add_tail(&edge->list[UPPER], &upper->lower); 806 continue; 807 } 808 809 BUG_ON(!upper->checked); 810 rb_node = tree_insert(&cache->rb_root, upper->bytenr, 811 &upper->rb_node); 812 BUG_ON(rb_node); 813 814 list_add_tail(&edge->list[UPPER], &upper->lower); 815 816 list_for_each_entry(edge, &upper->upper, list[LOWER]) 817 list_add_tail(&edge->list[UPPER], &list); 818 } 819 out: 820 btrfs_free_path(path1); 821 btrfs_free_path(path2); 822 if (err) { 823 INIT_LIST_HEAD(&list); 824 upper = node; 825 while (upper) { 826 if (RB_EMPTY_NODE(&upper->rb_node)) { 827 list_splice_tail(&upper->upper, &list); 828 kfree(upper); 829 } 830 831 if (list_empty(&list)) 832 break; 833 834 edge = list_entry(list.next, struct backref_edge, 835 list[LOWER]); 836 upper = edge->node[UPPER]; 837 kfree(edge); 838 } 839 return ERR_PTR(err); 840 } 841 return node; 842 } 843 844 /* 845 * helper to add 'address of tree root -> reloc tree' mapping 846 */ 847 static int __add_reloc_root(struct btrfs_root *root) 848 { 849 struct rb_node *rb_node; 850 struct mapping_node *node; 851 struct reloc_control *rc = root->fs_info->reloc_ctl; 852 853 node = kmalloc(sizeof(*node), GFP_NOFS); 854 BUG_ON(!node); 855 856 node->bytenr = root->node->start; 857 node->data = root; 858 859 spin_lock(&rc->reloc_root_tree.lock); 860 rb_node = tree_insert(&rc->reloc_root_tree.rb_root, 861 node->bytenr, &node->rb_node); 862 spin_unlock(&rc->reloc_root_tree.lock); 863 BUG_ON(rb_node); 864 865 list_add_tail(&root->root_list, &rc->reloc_roots); 866 return 0; 867 } 868 869 /* 870 * helper to update/delete the 'address of tree root -> reloc tree' 871 * mapping 872 */ 873 static int __update_reloc_root(struct btrfs_root *root, int del) 874 { 875 struct rb_node *rb_node; 876 struct mapping_node *node = NULL; 877 struct reloc_control *rc = root->fs_info->reloc_ctl; 878 879 spin_lock(&rc->reloc_root_tree.lock); 880 rb_node = tree_search(&rc->reloc_root_tree.rb_root, 881 root->commit_root->start); 882 if (rb_node) { 883 node = rb_entry(rb_node, struct mapping_node, rb_node); 884 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root); 885 } 886 spin_unlock(&rc->reloc_root_tree.lock); 887 888 BUG_ON((struct btrfs_root *)node->data != root); 889 890 if (!del) { 891 spin_lock(&rc->reloc_root_tree.lock); 892 node->bytenr = root->node->start; 893 rb_node = tree_insert(&rc->reloc_root_tree.rb_root, 894 node->bytenr, &node->rb_node); 895 spin_unlock(&rc->reloc_root_tree.lock); 896 BUG_ON(rb_node); 897 } else { 898 list_del_init(&root->root_list); 899 kfree(node); 900 } 901 return 0; 902 } 903 904 /* 905 * create reloc tree for a given fs tree. reloc tree is just a 906 * snapshot of the fs tree with special root objectid. 907 */ 908 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans, 909 struct btrfs_root *root) 910 { 911 struct btrfs_root *reloc_root; 912 struct extent_buffer *eb; 913 struct btrfs_root_item *root_item; 914 struct btrfs_key root_key; 915 int ret; 916 917 if (root->reloc_root) { 918 reloc_root = root->reloc_root; 919 reloc_root->last_trans = trans->transid; 920 return 0; 921 } 922 923 if (!root->fs_info->reloc_ctl || 924 !root->fs_info->reloc_ctl->create_reloc_root || 925 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) 926 return 0; 927 928 root_item = kmalloc(sizeof(*root_item), GFP_NOFS); 929 BUG_ON(!root_item); 930 931 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID; 932 root_key.type = BTRFS_ROOT_ITEM_KEY; 933 root_key.offset = root->root_key.objectid; 934 935 ret = btrfs_copy_root(trans, root, root->commit_root, &eb, 936 BTRFS_TREE_RELOC_OBJECTID); 937 BUG_ON(ret); 938 939 btrfs_set_root_last_snapshot(&root->root_item, trans->transid - 1); 940 memcpy(root_item, &root->root_item, sizeof(*root_item)); 941 btrfs_set_root_refs(root_item, 1); 942 btrfs_set_root_bytenr(root_item, eb->start); 943 btrfs_set_root_level(root_item, btrfs_header_level(eb)); 944 btrfs_set_root_generation(root_item, trans->transid); 945 memset(&root_item->drop_progress, 0, sizeof(struct btrfs_disk_key)); 946 root_item->drop_level = 0; 947 948 btrfs_tree_unlock(eb); 949 free_extent_buffer(eb); 950 951 ret = btrfs_insert_root(trans, root->fs_info->tree_root, 952 &root_key, root_item); 953 BUG_ON(ret); 954 kfree(root_item); 955 956 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root, 957 &root_key); 958 BUG_ON(IS_ERR(reloc_root)); 959 reloc_root->last_trans = trans->transid; 960 961 __add_reloc_root(reloc_root); 962 root->reloc_root = reloc_root; 963 return 0; 964 } 965 966 /* 967 * update root item of reloc tree 968 */ 969 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans, 970 struct btrfs_root *root) 971 { 972 struct btrfs_root *reloc_root; 973 struct btrfs_root_item *root_item; 974 int del = 0; 975 int ret; 976 977 if (!root->reloc_root) 978 return 0; 979 980 reloc_root = root->reloc_root; 981 root_item = &reloc_root->root_item; 982 983 if (btrfs_root_refs(root_item) == 0) { 984 root->reloc_root = NULL; 985 del = 1; 986 } 987 988 __update_reloc_root(reloc_root, del); 989 990 if (reloc_root->commit_root != reloc_root->node) { 991 btrfs_set_root_node(root_item, reloc_root->node); 992 free_extent_buffer(reloc_root->commit_root); 993 reloc_root->commit_root = btrfs_root_node(reloc_root); 994 } 995 996 ret = btrfs_update_root(trans, root->fs_info->tree_root, 997 &reloc_root->root_key, root_item); 998 BUG_ON(ret); 999 return 0; 1000 } 1001 1002 /* 1003 * helper to find first cached inode with inode number >= objectid 1004 * in a subvolume 1005 */ 1006 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid) 1007 { 1008 struct rb_node *node; 1009 struct rb_node *prev; 1010 struct btrfs_inode *entry; 1011 struct inode *inode; 1012 1013 spin_lock(&root->inode_lock); 1014 again: 1015 node = root->inode_tree.rb_node; 1016 prev = NULL; 1017 while (node) { 1018 prev = node; 1019 entry = rb_entry(node, struct btrfs_inode, rb_node); 1020 1021 if (objectid < entry->vfs_inode.i_ino) 1022 node = node->rb_left; 1023 else if (objectid > entry->vfs_inode.i_ino) 1024 node = node->rb_right; 1025 else 1026 break; 1027 } 1028 if (!node) { 1029 while (prev) { 1030 entry = rb_entry(prev, struct btrfs_inode, rb_node); 1031 if (objectid <= entry->vfs_inode.i_ino) { 1032 node = prev; 1033 break; 1034 } 1035 prev = rb_next(prev); 1036 } 1037 } 1038 while (node) { 1039 entry = rb_entry(node, struct btrfs_inode, rb_node); 1040 inode = igrab(&entry->vfs_inode); 1041 if (inode) { 1042 spin_unlock(&root->inode_lock); 1043 return inode; 1044 } 1045 1046 objectid = entry->vfs_inode.i_ino + 1; 1047 if (cond_resched_lock(&root->inode_lock)) 1048 goto again; 1049 1050 node = rb_next(node); 1051 } 1052 spin_unlock(&root->inode_lock); 1053 return NULL; 1054 } 1055 1056 static int in_block_group(u64 bytenr, 1057 struct btrfs_block_group_cache *block_group) 1058 { 1059 if (bytenr >= block_group->key.objectid && 1060 bytenr < block_group->key.objectid + block_group->key.offset) 1061 return 1; 1062 return 0; 1063 } 1064 1065 /* 1066 * get new location of data 1067 */ 1068 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr, 1069 u64 bytenr, u64 num_bytes) 1070 { 1071 struct btrfs_root *root = BTRFS_I(reloc_inode)->root; 1072 struct btrfs_path *path; 1073 struct btrfs_file_extent_item *fi; 1074 struct extent_buffer *leaf; 1075 int ret; 1076 1077 path = btrfs_alloc_path(); 1078 if (!path) 1079 return -ENOMEM; 1080 1081 bytenr -= BTRFS_I(reloc_inode)->index_cnt; 1082 ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino, 1083 bytenr, 0); 1084 if (ret < 0) 1085 goto out; 1086 if (ret > 0) { 1087 ret = -ENOENT; 1088 goto out; 1089 } 1090 1091 leaf = path->nodes[0]; 1092 fi = btrfs_item_ptr(leaf, path->slots[0], 1093 struct btrfs_file_extent_item); 1094 1095 BUG_ON(btrfs_file_extent_offset(leaf, fi) || 1096 btrfs_file_extent_compression(leaf, fi) || 1097 btrfs_file_extent_encryption(leaf, fi) || 1098 btrfs_file_extent_other_encoding(leaf, fi)); 1099 1100 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) { 1101 ret = 1; 1102 goto out; 1103 } 1104 1105 if (new_bytenr) 1106 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); 1107 ret = 0; 1108 out: 1109 btrfs_free_path(path); 1110 return ret; 1111 } 1112 1113 /* 1114 * update file extent items in the tree leaf to point to 1115 * the new locations. 1116 */ 1117 static int replace_file_extents(struct btrfs_trans_handle *trans, 1118 struct reloc_control *rc, 1119 struct btrfs_root *root, 1120 struct extent_buffer *leaf, 1121 struct list_head *inode_list) 1122 { 1123 struct btrfs_key key; 1124 struct btrfs_file_extent_item *fi; 1125 struct inode *inode = NULL; 1126 struct inodevec *ivec = NULL; 1127 u64 parent; 1128 u64 bytenr; 1129 u64 new_bytenr; 1130 u64 num_bytes; 1131 u64 end; 1132 u32 nritems; 1133 u32 i; 1134 int ret; 1135 int first = 1; 1136 int dirty = 0; 1137 1138 if (rc->stage != UPDATE_DATA_PTRS) 1139 return 0; 1140 1141 /* reloc trees always use full backref */ 1142 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) 1143 parent = leaf->start; 1144 else 1145 parent = 0; 1146 1147 nritems = btrfs_header_nritems(leaf); 1148 for (i = 0; i < nritems; i++) { 1149 cond_resched(); 1150 btrfs_item_key_to_cpu(leaf, &key, i); 1151 if (key.type != BTRFS_EXTENT_DATA_KEY) 1152 continue; 1153 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item); 1154 if (btrfs_file_extent_type(leaf, fi) == 1155 BTRFS_FILE_EXTENT_INLINE) 1156 continue; 1157 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); 1158 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); 1159 if (bytenr == 0) 1160 continue; 1161 if (!in_block_group(bytenr, rc->block_group)) 1162 continue; 1163 1164 /* 1165 * if we are modifying block in fs tree, wait for readpage 1166 * to complete and drop the extent cache 1167 */ 1168 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) { 1169 if (!ivec || ivec->nr == INODEVEC_SIZE) { 1170 ivec = kmalloc(sizeof(*ivec), GFP_NOFS); 1171 BUG_ON(!ivec); 1172 ivec->nr = 0; 1173 list_add_tail(&ivec->list, inode_list); 1174 } 1175 if (first) { 1176 inode = find_next_inode(root, key.objectid); 1177 if (inode) 1178 ivec->inode[ivec->nr++] = inode; 1179 first = 0; 1180 } else if (inode && inode->i_ino < key.objectid) { 1181 inode = find_next_inode(root, key.objectid); 1182 if (inode) 1183 ivec->inode[ivec->nr++] = inode; 1184 } 1185 if (inode && inode->i_ino == key.objectid) { 1186 end = key.offset + 1187 btrfs_file_extent_num_bytes(leaf, fi); 1188 WARN_ON(!IS_ALIGNED(key.offset, 1189 root->sectorsize)); 1190 WARN_ON(!IS_ALIGNED(end, root->sectorsize)); 1191 end--; 1192 ret = try_lock_extent(&BTRFS_I(inode)->io_tree, 1193 key.offset, end, 1194 GFP_NOFS); 1195 if (!ret) 1196 continue; 1197 1198 btrfs_drop_extent_cache(inode, key.offset, end, 1199 1); 1200 unlock_extent(&BTRFS_I(inode)->io_tree, 1201 key.offset, end, GFP_NOFS); 1202 } 1203 } 1204 1205 ret = get_new_location(rc->data_inode, &new_bytenr, 1206 bytenr, num_bytes); 1207 if (ret > 0) 1208 continue; 1209 BUG_ON(ret < 0); 1210 1211 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr); 1212 dirty = 1; 1213 1214 key.offset -= btrfs_file_extent_offset(leaf, fi); 1215 ret = btrfs_inc_extent_ref(trans, root, new_bytenr, 1216 num_bytes, parent, 1217 btrfs_header_owner(leaf), 1218 key.objectid, key.offset); 1219 BUG_ON(ret); 1220 1221 ret = btrfs_free_extent(trans, root, bytenr, num_bytes, 1222 parent, btrfs_header_owner(leaf), 1223 key.objectid, key.offset); 1224 BUG_ON(ret); 1225 } 1226 if (dirty) 1227 btrfs_mark_buffer_dirty(leaf); 1228 return 0; 1229 } 1230 1231 static noinline_for_stack 1232 int memcmp_node_keys(struct extent_buffer *eb, int slot, 1233 struct btrfs_path *path, int level) 1234 { 1235 struct btrfs_disk_key key1; 1236 struct btrfs_disk_key key2; 1237 btrfs_node_key(eb, &key1, slot); 1238 btrfs_node_key(path->nodes[level], &key2, path->slots[level]); 1239 return memcmp(&key1, &key2, sizeof(key1)); 1240 } 1241 1242 /* 1243 * try to replace tree blocks in fs tree with the new blocks 1244 * in reloc tree. tree blocks haven't been modified since the 1245 * reloc tree was create can be replaced. 1246 * 1247 * if a block was replaced, level of the block + 1 is returned. 1248 * if no block got replaced, 0 is returned. if there are other 1249 * errors, a negative error number is returned. 1250 */ 1251 static int replace_path(struct btrfs_trans_handle *trans, 1252 struct btrfs_root *dest, struct btrfs_root *src, 1253 struct btrfs_path *path, struct btrfs_key *next_key, 1254 struct extent_buffer **leaf, 1255 int lowest_level, int max_level) 1256 { 1257 struct extent_buffer *eb; 1258 struct extent_buffer *parent; 1259 struct btrfs_key key; 1260 u64 old_bytenr; 1261 u64 new_bytenr; 1262 u64 old_ptr_gen; 1263 u64 new_ptr_gen; 1264 u64 last_snapshot; 1265 u32 blocksize; 1266 int level; 1267 int ret; 1268 int slot; 1269 1270 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID); 1271 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID); 1272 BUG_ON(lowest_level > 1 && leaf); 1273 1274 last_snapshot = btrfs_root_last_snapshot(&src->root_item); 1275 1276 slot = path->slots[lowest_level]; 1277 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot); 1278 1279 eb = btrfs_lock_root_node(dest); 1280 btrfs_set_lock_blocking(eb); 1281 level = btrfs_header_level(eb); 1282 1283 if (level < lowest_level) { 1284 btrfs_tree_unlock(eb); 1285 free_extent_buffer(eb); 1286 return 0; 1287 } 1288 1289 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb); 1290 BUG_ON(ret); 1291 btrfs_set_lock_blocking(eb); 1292 1293 if (next_key) { 1294 next_key->objectid = (u64)-1; 1295 next_key->type = (u8)-1; 1296 next_key->offset = (u64)-1; 1297 } 1298 1299 parent = eb; 1300 while (1) { 1301 level = btrfs_header_level(parent); 1302 BUG_ON(level < lowest_level); 1303 1304 ret = btrfs_bin_search(parent, &key, level, &slot); 1305 if (ret && slot > 0) 1306 slot--; 1307 1308 if (next_key && slot + 1 < btrfs_header_nritems(parent)) 1309 btrfs_node_key_to_cpu(parent, next_key, slot + 1); 1310 1311 old_bytenr = btrfs_node_blockptr(parent, slot); 1312 blocksize = btrfs_level_size(dest, level - 1); 1313 old_ptr_gen = btrfs_node_ptr_generation(parent, slot); 1314 1315 if (level <= max_level) { 1316 eb = path->nodes[level]; 1317 new_bytenr = btrfs_node_blockptr(eb, 1318 path->slots[level]); 1319 new_ptr_gen = btrfs_node_ptr_generation(eb, 1320 path->slots[level]); 1321 } else { 1322 new_bytenr = 0; 1323 new_ptr_gen = 0; 1324 } 1325 1326 if (new_bytenr > 0 && new_bytenr == old_bytenr) { 1327 WARN_ON(1); 1328 ret = level; 1329 break; 1330 } 1331 1332 if (new_bytenr == 0 || old_ptr_gen > last_snapshot || 1333 memcmp_node_keys(parent, slot, path, level)) { 1334 if (level <= lowest_level && !leaf) { 1335 ret = 0; 1336 break; 1337 } 1338 1339 eb = read_tree_block(dest, old_bytenr, blocksize, 1340 old_ptr_gen); 1341 btrfs_tree_lock(eb); 1342 ret = btrfs_cow_block(trans, dest, eb, parent, 1343 slot, &eb); 1344 BUG_ON(ret); 1345 btrfs_set_lock_blocking(eb); 1346 1347 if (level <= lowest_level) { 1348 *leaf = eb; 1349 ret = 0; 1350 break; 1351 } 1352 1353 btrfs_tree_unlock(parent); 1354 free_extent_buffer(parent); 1355 1356 parent = eb; 1357 continue; 1358 } 1359 1360 btrfs_node_key_to_cpu(path->nodes[level], &key, 1361 path->slots[level]); 1362 btrfs_release_path(src, path); 1363 1364 path->lowest_level = level; 1365 ret = btrfs_search_slot(trans, src, &key, path, 0, 1); 1366 path->lowest_level = 0; 1367 BUG_ON(ret); 1368 1369 /* 1370 * swap blocks in fs tree and reloc tree. 1371 */ 1372 btrfs_set_node_blockptr(parent, slot, new_bytenr); 1373 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen); 1374 btrfs_mark_buffer_dirty(parent); 1375 1376 btrfs_set_node_blockptr(path->nodes[level], 1377 path->slots[level], old_bytenr); 1378 btrfs_set_node_ptr_generation(path->nodes[level], 1379 path->slots[level], old_ptr_gen); 1380 btrfs_mark_buffer_dirty(path->nodes[level]); 1381 1382 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize, 1383 path->nodes[level]->start, 1384 src->root_key.objectid, level - 1, 0); 1385 BUG_ON(ret); 1386 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize, 1387 0, dest->root_key.objectid, level - 1, 1388 0); 1389 BUG_ON(ret); 1390 1391 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize, 1392 path->nodes[level]->start, 1393 src->root_key.objectid, level - 1, 0); 1394 BUG_ON(ret); 1395 1396 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize, 1397 0, dest->root_key.objectid, level - 1, 1398 0); 1399 BUG_ON(ret); 1400 1401 btrfs_unlock_up_safe(path, 0); 1402 1403 ret = level; 1404 break; 1405 } 1406 btrfs_tree_unlock(parent); 1407 free_extent_buffer(parent); 1408 return ret; 1409 } 1410 1411 /* 1412 * helper to find next relocated block in reloc tree 1413 */ 1414 static noinline_for_stack 1415 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path, 1416 int *level) 1417 { 1418 struct extent_buffer *eb; 1419 int i; 1420 u64 last_snapshot; 1421 u32 nritems; 1422 1423 last_snapshot = btrfs_root_last_snapshot(&root->root_item); 1424 1425 for (i = 0; i < *level; i++) { 1426 free_extent_buffer(path->nodes[i]); 1427 path->nodes[i] = NULL; 1428 } 1429 1430 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) { 1431 eb = path->nodes[i]; 1432 nritems = btrfs_header_nritems(eb); 1433 while (path->slots[i] + 1 < nritems) { 1434 path->slots[i]++; 1435 if (btrfs_node_ptr_generation(eb, path->slots[i]) <= 1436 last_snapshot) 1437 continue; 1438 1439 *level = i; 1440 return 0; 1441 } 1442 free_extent_buffer(path->nodes[i]); 1443 path->nodes[i] = NULL; 1444 } 1445 return 1; 1446 } 1447 1448 /* 1449 * walk down reloc tree to find relocated block of lowest level 1450 */ 1451 static noinline_for_stack 1452 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path, 1453 int *level) 1454 { 1455 struct extent_buffer *eb = NULL; 1456 int i; 1457 u64 bytenr; 1458 u64 ptr_gen = 0; 1459 u64 last_snapshot; 1460 u32 blocksize; 1461 u32 nritems; 1462 1463 last_snapshot = btrfs_root_last_snapshot(&root->root_item); 1464 1465 for (i = *level; i > 0; i--) { 1466 eb = path->nodes[i]; 1467 nritems = btrfs_header_nritems(eb); 1468 while (path->slots[i] < nritems) { 1469 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]); 1470 if (ptr_gen > last_snapshot) 1471 break; 1472 path->slots[i]++; 1473 } 1474 if (path->slots[i] >= nritems) { 1475 if (i == *level) 1476 break; 1477 *level = i + 1; 1478 return 0; 1479 } 1480 if (i == 1) { 1481 *level = i; 1482 return 0; 1483 } 1484 1485 bytenr = btrfs_node_blockptr(eb, path->slots[i]); 1486 blocksize = btrfs_level_size(root, i - 1); 1487 eb = read_tree_block(root, bytenr, blocksize, ptr_gen); 1488 BUG_ON(btrfs_header_level(eb) != i - 1); 1489 path->nodes[i - 1] = eb; 1490 path->slots[i - 1] = 0; 1491 } 1492 return 1; 1493 } 1494 1495 /* 1496 * invalidate extent cache for file extents whose key in range of 1497 * [min_key, max_key) 1498 */ 1499 static int invalidate_extent_cache(struct btrfs_root *root, 1500 struct btrfs_key *min_key, 1501 struct btrfs_key *max_key) 1502 { 1503 struct inode *inode = NULL; 1504 u64 objectid; 1505 u64 start, end; 1506 1507 objectid = min_key->objectid; 1508 while (1) { 1509 cond_resched(); 1510 iput(inode); 1511 1512 if (objectid > max_key->objectid) 1513 break; 1514 1515 inode = find_next_inode(root, objectid); 1516 if (!inode) 1517 break; 1518 1519 if (inode->i_ino > max_key->objectid) { 1520 iput(inode); 1521 break; 1522 } 1523 1524 objectid = inode->i_ino + 1; 1525 if (!S_ISREG(inode->i_mode)) 1526 continue; 1527 1528 if (unlikely(min_key->objectid == inode->i_ino)) { 1529 if (min_key->type > BTRFS_EXTENT_DATA_KEY) 1530 continue; 1531 if (min_key->type < BTRFS_EXTENT_DATA_KEY) 1532 start = 0; 1533 else { 1534 start = min_key->offset; 1535 WARN_ON(!IS_ALIGNED(start, root->sectorsize)); 1536 } 1537 } else { 1538 start = 0; 1539 } 1540 1541 if (unlikely(max_key->objectid == inode->i_ino)) { 1542 if (max_key->type < BTRFS_EXTENT_DATA_KEY) 1543 continue; 1544 if (max_key->type > BTRFS_EXTENT_DATA_KEY) { 1545 end = (u64)-1; 1546 } else { 1547 if (max_key->offset == 0) 1548 continue; 1549 end = max_key->offset; 1550 WARN_ON(!IS_ALIGNED(end, root->sectorsize)); 1551 end--; 1552 } 1553 } else { 1554 end = (u64)-1; 1555 } 1556 1557 /* the lock_extent waits for readpage to complete */ 1558 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); 1559 btrfs_drop_extent_cache(inode, start, end, 1); 1560 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); 1561 } 1562 return 0; 1563 } 1564 1565 static void put_inodes(struct list_head *list) 1566 { 1567 struct inodevec *ivec; 1568 while (!list_empty(list)) { 1569 ivec = list_entry(list->next, struct inodevec, list); 1570 list_del(&ivec->list); 1571 while (ivec->nr > 0) { 1572 ivec->nr--; 1573 iput(ivec->inode[ivec->nr]); 1574 } 1575 kfree(ivec); 1576 } 1577 } 1578 1579 static int find_next_key(struct btrfs_path *path, int level, 1580 struct btrfs_key *key) 1581 1582 { 1583 while (level < BTRFS_MAX_LEVEL) { 1584 if (!path->nodes[level]) 1585 break; 1586 if (path->slots[level] + 1 < 1587 btrfs_header_nritems(path->nodes[level])) { 1588 btrfs_node_key_to_cpu(path->nodes[level], key, 1589 path->slots[level] + 1); 1590 return 0; 1591 } 1592 level++; 1593 } 1594 return 1; 1595 } 1596 1597 /* 1598 * merge the relocated tree blocks in reloc tree with corresponding 1599 * fs tree. 1600 */ 1601 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc, 1602 struct btrfs_root *root) 1603 { 1604 LIST_HEAD(inode_list); 1605 struct btrfs_key key; 1606 struct btrfs_key next_key; 1607 struct btrfs_trans_handle *trans; 1608 struct btrfs_root *reloc_root; 1609 struct btrfs_root_item *root_item; 1610 struct btrfs_path *path; 1611 struct extent_buffer *leaf = NULL; 1612 unsigned long nr; 1613 int level; 1614 int max_level; 1615 int replaced = 0; 1616 int ret; 1617 int err = 0; 1618 1619 path = btrfs_alloc_path(); 1620 if (!path) 1621 return -ENOMEM; 1622 1623 reloc_root = root->reloc_root; 1624 root_item = &reloc_root->root_item; 1625 1626 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) { 1627 level = btrfs_root_level(root_item); 1628 extent_buffer_get(reloc_root->node); 1629 path->nodes[level] = reloc_root->node; 1630 path->slots[level] = 0; 1631 } else { 1632 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress); 1633 1634 level = root_item->drop_level; 1635 BUG_ON(level == 0); 1636 path->lowest_level = level; 1637 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0); 1638 path->lowest_level = 0; 1639 if (ret < 0) { 1640 btrfs_free_path(path); 1641 return ret; 1642 } 1643 1644 btrfs_node_key_to_cpu(path->nodes[level], &next_key, 1645 path->slots[level]); 1646 WARN_ON(memcmp(&key, &next_key, sizeof(key))); 1647 1648 btrfs_unlock_up_safe(path, 0); 1649 } 1650 1651 if (level == 0 && rc->stage == UPDATE_DATA_PTRS) { 1652 trans = btrfs_start_transaction(root, 1); 1653 1654 leaf = path->nodes[0]; 1655 btrfs_item_key_to_cpu(leaf, &key, 0); 1656 btrfs_release_path(reloc_root, path); 1657 1658 ret = btrfs_search_slot(trans, root, &key, path, 0, 1); 1659 if (ret < 0) { 1660 err = ret; 1661 goto out; 1662 } 1663 1664 leaf = path->nodes[0]; 1665 btrfs_unlock_up_safe(path, 1); 1666 ret = replace_file_extents(trans, rc, root, leaf, 1667 &inode_list); 1668 if (ret < 0) 1669 err = ret; 1670 goto out; 1671 } 1672 1673 memset(&next_key, 0, sizeof(next_key)); 1674 1675 while (1) { 1676 leaf = NULL; 1677 replaced = 0; 1678 trans = btrfs_start_transaction(root, 1); 1679 max_level = level; 1680 1681 ret = walk_down_reloc_tree(reloc_root, path, &level); 1682 if (ret < 0) { 1683 err = ret; 1684 goto out; 1685 } 1686 if (ret > 0) 1687 break; 1688 1689 if (!find_next_key(path, level, &key) && 1690 btrfs_comp_cpu_keys(&next_key, &key) >= 0) { 1691 ret = 0; 1692 } else if (level == 1 && rc->stage == UPDATE_DATA_PTRS) { 1693 ret = replace_path(trans, root, reloc_root, 1694 path, &next_key, &leaf, 1695 level, max_level); 1696 } else { 1697 ret = replace_path(trans, root, reloc_root, 1698 path, &next_key, NULL, 1699 level, max_level); 1700 } 1701 if (ret < 0) { 1702 err = ret; 1703 goto out; 1704 } 1705 1706 if (ret > 0) { 1707 level = ret; 1708 btrfs_node_key_to_cpu(path->nodes[level], &key, 1709 path->slots[level]); 1710 replaced = 1; 1711 } else if (leaf) { 1712 /* 1713 * no block got replaced, try replacing file extents 1714 */ 1715 btrfs_item_key_to_cpu(leaf, &key, 0); 1716 ret = replace_file_extents(trans, rc, root, leaf, 1717 &inode_list); 1718 btrfs_tree_unlock(leaf); 1719 free_extent_buffer(leaf); 1720 BUG_ON(ret < 0); 1721 } 1722 1723 ret = walk_up_reloc_tree(reloc_root, path, &level); 1724 if (ret > 0) 1725 break; 1726 1727 BUG_ON(level == 0); 1728 /* 1729 * save the merging progress in the drop_progress. 1730 * this is OK since root refs == 1 in this case. 1731 */ 1732 btrfs_node_key(path->nodes[level], &root_item->drop_progress, 1733 path->slots[level]); 1734 root_item->drop_level = level; 1735 1736 nr = trans->blocks_used; 1737 btrfs_end_transaction(trans, root); 1738 1739 btrfs_btree_balance_dirty(root, nr); 1740 1741 /* 1742 * put inodes outside transaction, otherwise we may deadlock. 1743 */ 1744 put_inodes(&inode_list); 1745 1746 if (replaced && rc->stage == UPDATE_DATA_PTRS) 1747 invalidate_extent_cache(root, &key, &next_key); 1748 } 1749 1750 /* 1751 * handle the case only one block in the fs tree need to be 1752 * relocated and the block is tree root. 1753 */ 1754 leaf = btrfs_lock_root_node(root); 1755 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf); 1756 btrfs_tree_unlock(leaf); 1757 free_extent_buffer(leaf); 1758 if (ret < 0) 1759 err = ret; 1760 out: 1761 btrfs_free_path(path); 1762 1763 if (err == 0) { 1764 memset(&root_item->drop_progress, 0, 1765 sizeof(root_item->drop_progress)); 1766 root_item->drop_level = 0; 1767 btrfs_set_root_refs(root_item, 0); 1768 } 1769 1770 nr = trans->blocks_used; 1771 btrfs_end_transaction(trans, root); 1772 1773 btrfs_btree_balance_dirty(root, nr); 1774 1775 put_inodes(&inode_list); 1776 1777 if (replaced && rc->stage == UPDATE_DATA_PTRS) 1778 invalidate_extent_cache(root, &key, &next_key); 1779 1780 return err; 1781 } 1782 1783 /* 1784 * callback for the work threads. 1785 * this function merges reloc tree with corresponding fs tree, 1786 * and then drops the reloc tree. 1787 */ 1788 static void merge_func(struct btrfs_work *work) 1789 { 1790 struct btrfs_trans_handle *trans; 1791 struct btrfs_root *root; 1792 struct btrfs_root *reloc_root; 1793 struct async_merge *async; 1794 1795 async = container_of(work, struct async_merge, work); 1796 reloc_root = async->root; 1797 1798 if (btrfs_root_refs(&reloc_root->root_item) > 0) { 1799 root = read_fs_root(reloc_root->fs_info, 1800 reloc_root->root_key.offset); 1801 BUG_ON(IS_ERR(root)); 1802 BUG_ON(root->reloc_root != reloc_root); 1803 1804 merge_reloc_root(async->rc, root); 1805 1806 trans = btrfs_start_transaction(root, 1); 1807 btrfs_update_reloc_root(trans, root); 1808 btrfs_end_transaction(trans, root); 1809 } 1810 1811 btrfs_drop_snapshot(reloc_root, 0); 1812 1813 if (atomic_dec_and_test(async->num_pending)) 1814 complete(async->done); 1815 1816 kfree(async); 1817 } 1818 1819 static int merge_reloc_roots(struct reloc_control *rc) 1820 { 1821 struct async_merge *async; 1822 struct btrfs_root *root; 1823 struct completion done; 1824 atomic_t num_pending; 1825 1826 init_completion(&done); 1827 atomic_set(&num_pending, 1); 1828 1829 while (!list_empty(&rc->reloc_roots)) { 1830 root = list_entry(rc->reloc_roots.next, 1831 struct btrfs_root, root_list); 1832 list_del_init(&root->root_list); 1833 1834 async = kmalloc(sizeof(*async), GFP_NOFS); 1835 BUG_ON(!async); 1836 async->work.func = merge_func; 1837 async->work.flags = 0; 1838 async->rc = rc; 1839 async->root = root; 1840 async->done = &done; 1841 async->num_pending = &num_pending; 1842 atomic_inc(&num_pending); 1843 btrfs_queue_worker(&rc->workers, &async->work); 1844 } 1845 1846 if (!atomic_dec_and_test(&num_pending)) 1847 wait_for_completion(&done); 1848 1849 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root)); 1850 return 0; 1851 } 1852 1853 static void free_block_list(struct rb_root *blocks) 1854 { 1855 struct tree_block *block; 1856 struct rb_node *rb_node; 1857 while ((rb_node = rb_first(blocks))) { 1858 block = rb_entry(rb_node, struct tree_block, rb_node); 1859 rb_erase(rb_node, blocks); 1860 kfree(block); 1861 } 1862 } 1863 1864 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans, 1865 struct btrfs_root *reloc_root) 1866 { 1867 struct btrfs_root *root; 1868 1869 if (reloc_root->last_trans == trans->transid) 1870 return 0; 1871 1872 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset); 1873 BUG_ON(IS_ERR(root)); 1874 BUG_ON(root->reloc_root != reloc_root); 1875 1876 return btrfs_record_root_in_trans(trans, root); 1877 } 1878 1879 /* 1880 * select one tree from trees that references the block. 1881 * for blocks in refernce counted trees, we preper reloc tree. 1882 * if no reloc tree found and reloc_only is true, NULL is returned. 1883 */ 1884 static struct btrfs_root *__select_one_root(struct btrfs_trans_handle *trans, 1885 struct backref_node *node, 1886 struct backref_edge *edges[], 1887 int *nr, int reloc_only) 1888 { 1889 struct backref_node *next; 1890 struct btrfs_root *root; 1891 int index; 1892 int loop = 0; 1893 again: 1894 index = 0; 1895 next = node; 1896 while (1) { 1897 cond_resched(); 1898 next = walk_up_backref(next, edges, &index); 1899 root = next->root; 1900 if (!root) { 1901 BUG_ON(!node->old_root); 1902 goto skip; 1903 } 1904 1905 /* no other choice for non-refernce counted tree */ 1906 if (!root->ref_cows) { 1907 BUG_ON(reloc_only); 1908 break; 1909 } 1910 1911 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { 1912 record_reloc_root_in_trans(trans, root); 1913 break; 1914 } 1915 1916 if (loop) { 1917 btrfs_record_root_in_trans(trans, root); 1918 break; 1919 } 1920 1921 if (reloc_only || next != node) { 1922 if (!root->reloc_root) 1923 btrfs_record_root_in_trans(trans, root); 1924 root = root->reloc_root; 1925 /* 1926 * if the reloc tree was created in current 1927 * transation, there is no node in backref tree 1928 * corresponds to the root of the reloc tree. 1929 */ 1930 if (btrfs_root_last_snapshot(&root->root_item) == 1931 trans->transid - 1) 1932 break; 1933 } 1934 skip: 1935 root = NULL; 1936 next = walk_down_backref(edges, &index); 1937 if (!next || next->level <= node->level) 1938 break; 1939 } 1940 1941 if (!root && !loop && !reloc_only) { 1942 loop = 1; 1943 goto again; 1944 } 1945 1946 if (root) 1947 *nr = index; 1948 else 1949 *nr = 0; 1950 1951 return root; 1952 } 1953 1954 static noinline_for_stack 1955 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans, 1956 struct backref_node *node) 1957 { 1958 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; 1959 int nr; 1960 return __select_one_root(trans, node, edges, &nr, 0); 1961 } 1962 1963 static noinline_for_stack 1964 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans, 1965 struct backref_node *node, 1966 struct backref_edge *edges[], int *nr) 1967 { 1968 return __select_one_root(trans, node, edges, nr, 1); 1969 } 1970 1971 static void grab_path_buffers(struct btrfs_path *path, 1972 struct backref_node *node, 1973 struct backref_edge *edges[], int nr) 1974 { 1975 int i = 0; 1976 while (1) { 1977 drop_node_buffer(node); 1978 node->eb = path->nodes[node->level]; 1979 BUG_ON(!node->eb); 1980 if (path->locks[node->level]) 1981 node->locked = 1; 1982 path->nodes[node->level] = NULL; 1983 path->locks[node->level] = 0; 1984 1985 if (i >= nr) 1986 break; 1987 1988 edges[i]->blockptr = node->eb->start; 1989 node = edges[i]->node[UPPER]; 1990 i++; 1991 } 1992 } 1993 1994 /* 1995 * relocate a block tree, and then update pointers in upper level 1996 * blocks that reference the block to point to the new location. 1997 * 1998 * if called by link_to_upper, the block has already been relocated. 1999 * in that case this function just updates pointers. 2000 */ 2001 static int do_relocation(struct btrfs_trans_handle *trans, 2002 struct backref_node *node, 2003 struct btrfs_key *key, 2004 struct btrfs_path *path, int lowest) 2005 { 2006 struct backref_node *upper; 2007 struct backref_edge *edge; 2008 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; 2009 struct btrfs_root *root; 2010 struct extent_buffer *eb; 2011 u32 blocksize; 2012 u64 bytenr; 2013 u64 generation; 2014 int nr; 2015 int slot; 2016 int ret; 2017 int err = 0; 2018 2019 BUG_ON(lowest && node->eb); 2020 2021 path->lowest_level = node->level + 1; 2022 list_for_each_entry(edge, &node->upper, list[LOWER]) { 2023 cond_resched(); 2024 if (node->eb && node->eb->start == edge->blockptr) 2025 continue; 2026 2027 upper = edge->node[UPPER]; 2028 root = select_reloc_root(trans, upper, edges, &nr); 2029 if (!root) 2030 continue; 2031 2032 if (upper->eb && !upper->locked) 2033 drop_node_buffer(upper); 2034 2035 if (!upper->eb) { 2036 ret = btrfs_search_slot(trans, root, key, path, 0, 1); 2037 if (ret < 0) { 2038 err = ret; 2039 break; 2040 } 2041 BUG_ON(ret > 0); 2042 2043 slot = path->slots[upper->level]; 2044 2045 btrfs_unlock_up_safe(path, upper->level + 1); 2046 grab_path_buffers(path, upper, edges, nr); 2047 2048 btrfs_release_path(NULL, path); 2049 } else { 2050 ret = btrfs_bin_search(upper->eb, key, upper->level, 2051 &slot); 2052 BUG_ON(ret); 2053 } 2054 2055 bytenr = btrfs_node_blockptr(upper->eb, slot); 2056 if (!lowest) { 2057 if (node->eb->start == bytenr) { 2058 btrfs_tree_unlock(upper->eb); 2059 upper->locked = 0; 2060 continue; 2061 } 2062 } else { 2063 BUG_ON(node->bytenr != bytenr); 2064 } 2065 2066 blocksize = btrfs_level_size(root, node->level); 2067 generation = btrfs_node_ptr_generation(upper->eb, slot); 2068 eb = read_tree_block(root, bytenr, blocksize, generation); 2069 btrfs_tree_lock(eb); 2070 btrfs_set_lock_blocking(eb); 2071 2072 if (!node->eb) { 2073 ret = btrfs_cow_block(trans, root, eb, upper->eb, 2074 slot, &eb); 2075 if (ret < 0) { 2076 err = ret; 2077 break; 2078 } 2079 btrfs_set_lock_blocking(eb); 2080 node->eb = eb; 2081 node->locked = 1; 2082 } else { 2083 btrfs_set_node_blockptr(upper->eb, slot, 2084 node->eb->start); 2085 btrfs_set_node_ptr_generation(upper->eb, slot, 2086 trans->transid); 2087 btrfs_mark_buffer_dirty(upper->eb); 2088 2089 ret = btrfs_inc_extent_ref(trans, root, 2090 node->eb->start, blocksize, 2091 upper->eb->start, 2092 btrfs_header_owner(upper->eb), 2093 node->level, 0); 2094 BUG_ON(ret); 2095 2096 ret = btrfs_drop_subtree(trans, root, eb, upper->eb); 2097 BUG_ON(ret); 2098 } 2099 if (!lowest) { 2100 btrfs_tree_unlock(upper->eb); 2101 upper->locked = 0; 2102 } 2103 } 2104 path->lowest_level = 0; 2105 return err; 2106 } 2107 2108 static int link_to_upper(struct btrfs_trans_handle *trans, 2109 struct backref_node *node, 2110 struct btrfs_path *path) 2111 { 2112 struct btrfs_key key; 2113 if (!node->eb || list_empty(&node->upper)) 2114 return 0; 2115 2116 btrfs_node_key_to_cpu(node->eb, &key, 0); 2117 return do_relocation(trans, node, &key, path, 0); 2118 } 2119 2120 static int finish_pending_nodes(struct btrfs_trans_handle *trans, 2121 struct backref_cache *cache, 2122 struct btrfs_path *path) 2123 { 2124 struct backref_node *node; 2125 int level; 2126 int ret; 2127 int err = 0; 2128 2129 for (level = 0; level < BTRFS_MAX_LEVEL; level++) { 2130 while (!list_empty(&cache->pending[level])) { 2131 node = list_entry(cache->pending[level].next, 2132 struct backref_node, lower); 2133 BUG_ON(node->level != level); 2134 2135 ret = link_to_upper(trans, node, path); 2136 if (ret < 0) 2137 err = ret; 2138 /* 2139 * this remove the node from the pending list and 2140 * may add some other nodes to the level + 1 2141 * pending list 2142 */ 2143 remove_backref_node(cache, node); 2144 } 2145 } 2146 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root)); 2147 return err; 2148 } 2149 2150 static void mark_block_processed(struct reloc_control *rc, 2151 struct backref_node *node) 2152 { 2153 u32 blocksize; 2154 if (node->level == 0 || 2155 in_block_group(node->bytenr, rc->block_group)) { 2156 blocksize = btrfs_level_size(rc->extent_root, node->level); 2157 set_extent_bits(&rc->processed_blocks, node->bytenr, 2158 node->bytenr + blocksize - 1, EXTENT_DIRTY, 2159 GFP_NOFS); 2160 } 2161 node->processed = 1; 2162 } 2163 2164 /* 2165 * mark a block and all blocks directly/indirectly reference the block 2166 * as processed. 2167 */ 2168 static void update_processed_blocks(struct reloc_control *rc, 2169 struct backref_node *node) 2170 { 2171 struct backref_node *next = node; 2172 struct backref_edge *edge; 2173 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1]; 2174 int index = 0; 2175 2176 while (next) { 2177 cond_resched(); 2178 while (1) { 2179 if (next->processed) 2180 break; 2181 2182 mark_block_processed(rc, next); 2183 2184 if (list_empty(&next->upper)) 2185 break; 2186 2187 edge = list_entry(next->upper.next, 2188 struct backref_edge, list[LOWER]); 2189 edges[index++] = edge; 2190 next = edge->node[UPPER]; 2191 } 2192 next = walk_down_backref(edges, &index); 2193 } 2194 } 2195 2196 static int tree_block_processed(u64 bytenr, u32 blocksize, 2197 struct reloc_control *rc) 2198 { 2199 if (test_range_bit(&rc->processed_blocks, bytenr, 2200 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL)) 2201 return 1; 2202 return 0; 2203 } 2204 2205 /* 2206 * check if there are any file extent pointers in the leaf point to 2207 * data require processing 2208 */ 2209 static int check_file_extents(struct reloc_control *rc, 2210 u64 bytenr, u32 blocksize, u64 ptr_gen) 2211 { 2212 struct btrfs_key found_key; 2213 struct btrfs_file_extent_item *fi; 2214 struct extent_buffer *leaf; 2215 u32 nritems; 2216 int i; 2217 int ret = 0; 2218 2219 leaf = read_tree_block(rc->extent_root, bytenr, blocksize, ptr_gen); 2220 2221 nritems = btrfs_header_nritems(leaf); 2222 for (i = 0; i < nritems; i++) { 2223 cond_resched(); 2224 btrfs_item_key_to_cpu(leaf, &found_key, i); 2225 if (found_key.type != BTRFS_EXTENT_DATA_KEY) 2226 continue; 2227 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item); 2228 if (btrfs_file_extent_type(leaf, fi) == 2229 BTRFS_FILE_EXTENT_INLINE) 2230 continue; 2231 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); 2232 if (bytenr == 0) 2233 continue; 2234 if (in_block_group(bytenr, rc->block_group)) { 2235 ret = 1; 2236 break; 2237 } 2238 } 2239 free_extent_buffer(leaf); 2240 return ret; 2241 } 2242 2243 /* 2244 * scan child blocks of a given block to find blocks require processing 2245 */ 2246 static int add_child_blocks(struct btrfs_trans_handle *trans, 2247 struct reloc_control *rc, 2248 struct backref_node *node, 2249 struct rb_root *blocks) 2250 { 2251 struct tree_block *block; 2252 struct rb_node *rb_node; 2253 u64 bytenr; 2254 u64 ptr_gen; 2255 u32 blocksize; 2256 u32 nritems; 2257 int i; 2258 int err = 0; 2259 2260 nritems = btrfs_header_nritems(node->eb); 2261 blocksize = btrfs_level_size(rc->extent_root, node->level - 1); 2262 for (i = 0; i < nritems; i++) { 2263 cond_resched(); 2264 bytenr = btrfs_node_blockptr(node->eb, i); 2265 ptr_gen = btrfs_node_ptr_generation(node->eb, i); 2266 if (ptr_gen == trans->transid) 2267 continue; 2268 if (!in_block_group(bytenr, rc->block_group) && 2269 (node->level > 1 || rc->stage == MOVE_DATA_EXTENTS)) 2270 continue; 2271 if (tree_block_processed(bytenr, blocksize, rc)) 2272 continue; 2273 2274 readahead_tree_block(rc->extent_root, 2275 bytenr, blocksize, ptr_gen); 2276 } 2277 2278 for (i = 0; i < nritems; i++) { 2279 cond_resched(); 2280 bytenr = btrfs_node_blockptr(node->eb, i); 2281 ptr_gen = btrfs_node_ptr_generation(node->eb, i); 2282 if (ptr_gen == trans->transid) 2283 continue; 2284 if (!in_block_group(bytenr, rc->block_group) && 2285 (node->level > 1 || rc->stage == MOVE_DATA_EXTENTS)) 2286 continue; 2287 if (tree_block_processed(bytenr, blocksize, rc)) 2288 continue; 2289 if (!in_block_group(bytenr, rc->block_group) && 2290 !check_file_extents(rc, bytenr, blocksize, ptr_gen)) 2291 continue; 2292 2293 block = kmalloc(sizeof(*block), GFP_NOFS); 2294 if (!block) { 2295 err = -ENOMEM; 2296 break; 2297 } 2298 block->bytenr = bytenr; 2299 btrfs_node_key_to_cpu(node->eb, &block->key, i); 2300 block->level = node->level - 1; 2301 block->key_ready = 1; 2302 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node); 2303 BUG_ON(rb_node); 2304 } 2305 if (err) 2306 free_block_list(blocks); 2307 return err; 2308 } 2309 2310 /* 2311 * find adjacent blocks require processing 2312 */ 2313 static noinline_for_stack 2314 int add_adjacent_blocks(struct btrfs_trans_handle *trans, 2315 struct reloc_control *rc, 2316 struct backref_cache *cache, 2317 struct rb_root *blocks, int level, 2318 struct backref_node **upper) 2319 { 2320 struct backref_node *node; 2321 int ret = 0; 2322 2323 WARN_ON(!list_empty(&cache->pending[level])); 2324 2325 if (list_empty(&cache->pending[level + 1])) 2326 return 1; 2327 2328 node = list_entry(cache->pending[level + 1].next, 2329 struct backref_node, lower); 2330 if (node->eb) 2331 ret = add_child_blocks(trans, rc, node, blocks); 2332 2333 *upper = node; 2334 return ret; 2335 } 2336 2337 static int get_tree_block_key(struct reloc_control *rc, 2338 struct tree_block *block) 2339 { 2340 struct extent_buffer *eb; 2341 2342 BUG_ON(block->key_ready); 2343 eb = read_tree_block(rc->extent_root, block->bytenr, 2344 block->key.objectid, block->key.offset); 2345 WARN_ON(btrfs_header_level(eb) != block->level); 2346 if (block->level == 0) 2347 btrfs_item_key_to_cpu(eb, &block->key, 0); 2348 else 2349 btrfs_node_key_to_cpu(eb, &block->key, 0); 2350 free_extent_buffer(eb); 2351 block->key_ready = 1; 2352 return 0; 2353 } 2354 2355 static int reada_tree_block(struct reloc_control *rc, 2356 struct tree_block *block) 2357 { 2358 BUG_ON(block->key_ready); 2359 readahead_tree_block(rc->extent_root, block->bytenr, 2360 block->key.objectid, block->key.offset); 2361 return 0; 2362 } 2363 2364 /* 2365 * helper function to relocate a tree block 2366 */ 2367 static int relocate_tree_block(struct btrfs_trans_handle *trans, 2368 struct reloc_control *rc, 2369 struct backref_node *node, 2370 struct btrfs_key *key, 2371 struct btrfs_path *path) 2372 { 2373 struct btrfs_root *root; 2374 int ret; 2375 2376 root = select_one_root(trans, node); 2377 if (unlikely(!root)) { 2378 rc->found_old_snapshot = 1; 2379 update_processed_blocks(rc, node); 2380 return 0; 2381 } 2382 2383 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { 2384 ret = do_relocation(trans, node, key, path, 1); 2385 if (ret < 0) 2386 goto out; 2387 if (node->level == 0 && rc->stage == UPDATE_DATA_PTRS) { 2388 ret = replace_file_extents(trans, rc, root, 2389 node->eb, NULL); 2390 if (ret < 0) 2391 goto out; 2392 } 2393 drop_node_buffer(node); 2394 } else if (!root->ref_cows) { 2395 path->lowest_level = node->level; 2396 ret = btrfs_search_slot(trans, root, key, path, 0, 1); 2397 btrfs_release_path(root, path); 2398 if (ret < 0) 2399 goto out; 2400 } else if (root != node->root) { 2401 WARN_ON(node->level > 0 || rc->stage != UPDATE_DATA_PTRS); 2402 } 2403 2404 update_processed_blocks(rc, node); 2405 ret = 0; 2406 out: 2407 drop_node_buffer(node); 2408 return ret; 2409 } 2410 2411 /* 2412 * relocate a list of blocks 2413 */ 2414 static noinline_for_stack 2415 int relocate_tree_blocks(struct btrfs_trans_handle *trans, 2416 struct reloc_control *rc, struct rb_root *blocks) 2417 { 2418 struct backref_cache *cache; 2419 struct backref_node *node; 2420 struct btrfs_path *path; 2421 struct tree_block *block; 2422 struct rb_node *rb_node; 2423 int level = -1; 2424 int ret; 2425 int err = 0; 2426 2427 path = btrfs_alloc_path(); 2428 if (!path) 2429 return -ENOMEM; 2430 2431 cache = kmalloc(sizeof(*cache), GFP_NOFS); 2432 if (!cache) { 2433 btrfs_free_path(path); 2434 return -ENOMEM; 2435 } 2436 2437 backref_cache_init(cache); 2438 2439 rb_node = rb_first(blocks); 2440 while (rb_node) { 2441 block = rb_entry(rb_node, struct tree_block, rb_node); 2442 if (level == -1) 2443 level = block->level; 2444 else 2445 BUG_ON(level != block->level); 2446 if (!block->key_ready) 2447 reada_tree_block(rc, block); 2448 rb_node = rb_next(rb_node); 2449 } 2450 2451 rb_node = rb_first(blocks); 2452 while (rb_node) { 2453 block = rb_entry(rb_node, struct tree_block, rb_node); 2454 if (!block->key_ready) 2455 get_tree_block_key(rc, block); 2456 rb_node = rb_next(rb_node); 2457 } 2458 2459 rb_node = rb_first(blocks); 2460 while (rb_node) { 2461 block = rb_entry(rb_node, struct tree_block, rb_node); 2462 2463 node = build_backref_tree(rc, cache, &block->key, 2464 block->level, block->bytenr); 2465 if (IS_ERR(node)) { 2466 err = PTR_ERR(node); 2467 goto out; 2468 } 2469 2470 ret = relocate_tree_block(trans, rc, node, &block->key, 2471 path); 2472 if (ret < 0) { 2473 err = ret; 2474 goto out; 2475 } 2476 remove_backref_node(cache, node); 2477 rb_node = rb_next(rb_node); 2478 } 2479 2480 if (level > 0) 2481 goto out; 2482 2483 free_block_list(blocks); 2484 2485 /* 2486 * now backrefs of some upper level tree blocks have been cached, 2487 * try relocating blocks referenced by these upper level blocks. 2488 */ 2489 while (1) { 2490 struct backref_node *upper = NULL; 2491 if (trans->transaction->in_commit || 2492 trans->transaction->delayed_refs.flushing) 2493 break; 2494 2495 ret = add_adjacent_blocks(trans, rc, cache, blocks, level, 2496 &upper); 2497 if (ret < 0) 2498 err = ret; 2499 if (ret != 0) 2500 break; 2501 2502 rb_node = rb_first(blocks); 2503 while (rb_node) { 2504 block = rb_entry(rb_node, struct tree_block, rb_node); 2505 if (trans->transaction->in_commit || 2506 trans->transaction->delayed_refs.flushing) 2507 goto out; 2508 BUG_ON(!block->key_ready); 2509 node = build_backref_tree(rc, cache, &block->key, 2510 level, block->bytenr); 2511 if (IS_ERR(node)) { 2512 err = PTR_ERR(node); 2513 goto out; 2514 } 2515 2516 ret = relocate_tree_block(trans, rc, node, 2517 &block->key, path); 2518 if (ret < 0) { 2519 err = ret; 2520 goto out; 2521 } 2522 remove_backref_node(cache, node); 2523 rb_node = rb_next(rb_node); 2524 } 2525 free_block_list(blocks); 2526 2527 if (upper) { 2528 ret = link_to_upper(trans, upper, path); 2529 if (ret < 0) { 2530 err = ret; 2531 break; 2532 } 2533 remove_backref_node(cache, upper); 2534 } 2535 } 2536 out: 2537 free_block_list(blocks); 2538 2539 ret = finish_pending_nodes(trans, cache, path); 2540 if (ret < 0) 2541 err = ret; 2542 2543 kfree(cache); 2544 btrfs_free_path(path); 2545 return err; 2546 } 2547 2548 static noinline_for_stack 2549 int setup_extent_mapping(struct inode *inode, u64 start, u64 end, 2550 u64 block_start) 2551 { 2552 struct btrfs_root *root = BTRFS_I(inode)->root; 2553 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; 2554 struct extent_map *em; 2555 int ret = 0; 2556 2557 em = alloc_extent_map(GFP_NOFS); 2558 if (!em) 2559 return -ENOMEM; 2560 2561 em->start = start; 2562 em->len = end + 1 - start; 2563 em->block_len = em->len; 2564 em->block_start = block_start; 2565 em->bdev = root->fs_info->fs_devices->latest_bdev; 2566 set_bit(EXTENT_FLAG_PINNED, &em->flags); 2567 2568 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); 2569 while (1) { 2570 write_lock(&em_tree->lock); 2571 ret = add_extent_mapping(em_tree, em); 2572 write_unlock(&em_tree->lock); 2573 if (ret != -EEXIST) { 2574 free_extent_map(em); 2575 break; 2576 } 2577 btrfs_drop_extent_cache(inode, start, end, 0); 2578 } 2579 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS); 2580 return ret; 2581 } 2582 2583 static int relocate_file_extent_cluster(struct inode *inode, 2584 struct file_extent_cluster *cluster) 2585 { 2586 u64 page_start; 2587 u64 page_end; 2588 u64 offset = BTRFS_I(inode)->index_cnt; 2589 unsigned long index; 2590 unsigned long last_index; 2591 unsigned int dirty_page = 0; 2592 struct page *page; 2593 struct file_ra_state *ra; 2594 int nr = 0; 2595 int ret = 0; 2596 2597 if (!cluster->nr) 2598 return 0; 2599 2600 ra = kzalloc(sizeof(*ra), GFP_NOFS); 2601 if (!ra) 2602 return -ENOMEM; 2603 2604 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT; 2605 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT; 2606 2607 mutex_lock(&inode->i_mutex); 2608 2609 i_size_write(inode, cluster->end + 1 - offset); 2610 ret = setup_extent_mapping(inode, cluster->start - offset, 2611 cluster->end - offset, cluster->start); 2612 if (ret) 2613 goto out_unlock; 2614 2615 file_ra_state_init(ra, inode->i_mapping); 2616 2617 WARN_ON(cluster->start != cluster->boundary[0]); 2618 while (index <= last_index) { 2619 page = find_lock_page(inode->i_mapping, index); 2620 if (!page) { 2621 page_cache_sync_readahead(inode->i_mapping, 2622 ra, NULL, index, 2623 last_index + 1 - index); 2624 page = grab_cache_page(inode->i_mapping, index); 2625 if (!page) { 2626 ret = -ENOMEM; 2627 goto out_unlock; 2628 } 2629 } 2630 2631 if (PageReadahead(page)) { 2632 page_cache_async_readahead(inode->i_mapping, 2633 ra, NULL, page, index, 2634 last_index + 1 - index); 2635 } 2636 2637 if (!PageUptodate(page)) { 2638 btrfs_readpage(NULL, page); 2639 lock_page(page); 2640 if (!PageUptodate(page)) { 2641 unlock_page(page); 2642 page_cache_release(page); 2643 ret = -EIO; 2644 goto out_unlock; 2645 } 2646 } 2647 2648 page_start = (u64)page->index << PAGE_CACHE_SHIFT; 2649 page_end = page_start + PAGE_CACHE_SIZE - 1; 2650 2651 lock_extent(&BTRFS_I(inode)->io_tree, 2652 page_start, page_end, GFP_NOFS); 2653 2654 set_page_extent_mapped(page); 2655 2656 if (nr < cluster->nr && 2657 page_start + offset == cluster->boundary[nr]) { 2658 set_extent_bits(&BTRFS_I(inode)->io_tree, 2659 page_start, page_end, 2660 EXTENT_BOUNDARY, GFP_NOFS); 2661 nr++; 2662 } 2663 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL); 2664 2665 set_page_dirty(page); 2666 dirty_page++; 2667 2668 unlock_extent(&BTRFS_I(inode)->io_tree, 2669 page_start, page_end, GFP_NOFS); 2670 unlock_page(page); 2671 page_cache_release(page); 2672 2673 index++; 2674 if (nr < cluster->nr && 2675 page_end + 1 + offset == cluster->boundary[nr]) { 2676 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 2677 dirty_page); 2678 dirty_page = 0; 2679 } 2680 } 2681 if (dirty_page) { 2682 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 2683 dirty_page); 2684 } 2685 WARN_ON(nr != cluster->nr); 2686 out_unlock: 2687 mutex_unlock(&inode->i_mutex); 2688 kfree(ra); 2689 return ret; 2690 } 2691 2692 static noinline_for_stack 2693 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key, 2694 struct file_extent_cluster *cluster) 2695 { 2696 int ret; 2697 2698 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) { 2699 ret = relocate_file_extent_cluster(inode, cluster); 2700 if (ret) 2701 return ret; 2702 cluster->nr = 0; 2703 } 2704 2705 if (!cluster->nr) 2706 cluster->start = extent_key->objectid; 2707 else 2708 BUG_ON(cluster->nr >= MAX_EXTENTS); 2709 cluster->end = extent_key->objectid + extent_key->offset - 1; 2710 cluster->boundary[cluster->nr] = extent_key->objectid; 2711 cluster->nr++; 2712 2713 if (cluster->nr >= MAX_EXTENTS) { 2714 ret = relocate_file_extent_cluster(inode, cluster); 2715 if (ret) 2716 return ret; 2717 cluster->nr = 0; 2718 } 2719 return 0; 2720 } 2721 2722 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 2723 static int get_ref_objectid_v0(struct reloc_control *rc, 2724 struct btrfs_path *path, 2725 struct btrfs_key *extent_key, 2726 u64 *ref_objectid, int *path_change) 2727 { 2728 struct btrfs_key key; 2729 struct extent_buffer *leaf; 2730 struct btrfs_extent_ref_v0 *ref0; 2731 int ret; 2732 int slot; 2733 2734 leaf = path->nodes[0]; 2735 slot = path->slots[0]; 2736 while (1) { 2737 if (slot >= btrfs_header_nritems(leaf)) { 2738 ret = btrfs_next_leaf(rc->extent_root, path); 2739 if (ret < 0) 2740 return ret; 2741 BUG_ON(ret > 0); 2742 leaf = path->nodes[0]; 2743 slot = path->slots[0]; 2744 if (path_change) 2745 *path_change = 1; 2746 } 2747 btrfs_item_key_to_cpu(leaf, &key, slot); 2748 if (key.objectid != extent_key->objectid) 2749 return -ENOENT; 2750 2751 if (key.type != BTRFS_EXTENT_REF_V0_KEY) { 2752 slot++; 2753 continue; 2754 } 2755 ref0 = btrfs_item_ptr(leaf, slot, 2756 struct btrfs_extent_ref_v0); 2757 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0); 2758 break; 2759 } 2760 return 0; 2761 } 2762 #endif 2763 2764 /* 2765 * helper to add a tree block to the list. 2766 * the major work is getting the generation and level of the block 2767 */ 2768 static int add_tree_block(struct reloc_control *rc, 2769 struct btrfs_key *extent_key, 2770 struct btrfs_path *path, 2771 struct rb_root *blocks) 2772 { 2773 struct extent_buffer *eb; 2774 struct btrfs_extent_item *ei; 2775 struct btrfs_tree_block_info *bi; 2776 struct tree_block *block; 2777 struct rb_node *rb_node; 2778 u32 item_size; 2779 int level = -1; 2780 int generation; 2781 2782 eb = path->nodes[0]; 2783 item_size = btrfs_item_size_nr(eb, path->slots[0]); 2784 2785 if (item_size >= sizeof(*ei) + sizeof(*bi)) { 2786 ei = btrfs_item_ptr(eb, path->slots[0], 2787 struct btrfs_extent_item); 2788 bi = (struct btrfs_tree_block_info *)(ei + 1); 2789 generation = btrfs_extent_generation(eb, ei); 2790 level = btrfs_tree_block_level(eb, bi); 2791 } else { 2792 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 2793 u64 ref_owner; 2794 int ret; 2795 2796 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0)); 2797 ret = get_ref_objectid_v0(rc, path, extent_key, 2798 &ref_owner, NULL); 2799 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL); 2800 level = (int)ref_owner; 2801 /* FIXME: get real generation */ 2802 generation = 0; 2803 #else 2804 BUG(); 2805 #endif 2806 } 2807 2808 btrfs_release_path(rc->extent_root, path); 2809 2810 BUG_ON(level == -1); 2811 2812 block = kmalloc(sizeof(*block), GFP_NOFS); 2813 if (!block) 2814 return -ENOMEM; 2815 2816 block->bytenr = extent_key->objectid; 2817 block->key.objectid = extent_key->offset; 2818 block->key.offset = generation; 2819 block->level = level; 2820 block->key_ready = 0; 2821 2822 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node); 2823 BUG_ON(rb_node); 2824 2825 return 0; 2826 } 2827 2828 /* 2829 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY 2830 */ 2831 static int __add_tree_block(struct reloc_control *rc, 2832 u64 bytenr, u32 blocksize, 2833 struct rb_root *blocks) 2834 { 2835 struct btrfs_path *path; 2836 struct btrfs_key key; 2837 int ret; 2838 2839 if (tree_block_processed(bytenr, blocksize, rc)) 2840 return 0; 2841 2842 if (tree_search(blocks, bytenr)) 2843 return 0; 2844 2845 path = btrfs_alloc_path(); 2846 if (!path) 2847 return -ENOMEM; 2848 2849 key.objectid = bytenr; 2850 key.type = BTRFS_EXTENT_ITEM_KEY; 2851 key.offset = blocksize; 2852 2853 path->search_commit_root = 1; 2854 path->skip_locking = 1; 2855 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0); 2856 if (ret < 0) 2857 goto out; 2858 BUG_ON(ret); 2859 2860 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 2861 ret = add_tree_block(rc, &key, path, blocks); 2862 out: 2863 btrfs_free_path(path); 2864 return ret; 2865 } 2866 2867 /* 2868 * helper to check if the block use full backrefs for pointers in it 2869 */ 2870 static int block_use_full_backref(struct reloc_control *rc, 2871 struct extent_buffer *eb) 2872 { 2873 struct btrfs_path *path; 2874 struct btrfs_extent_item *ei; 2875 struct btrfs_key key; 2876 u64 flags; 2877 int ret; 2878 2879 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) || 2880 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV) 2881 return 1; 2882 2883 path = btrfs_alloc_path(); 2884 BUG_ON(!path); 2885 2886 key.objectid = eb->start; 2887 key.type = BTRFS_EXTENT_ITEM_KEY; 2888 key.offset = eb->len; 2889 2890 path->search_commit_root = 1; 2891 path->skip_locking = 1; 2892 ret = btrfs_search_slot(NULL, rc->extent_root, 2893 &key, path, 0, 0); 2894 BUG_ON(ret); 2895 2896 ei = btrfs_item_ptr(path->nodes[0], path->slots[0], 2897 struct btrfs_extent_item); 2898 flags = btrfs_extent_flags(path->nodes[0], ei); 2899 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)); 2900 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) 2901 ret = 1; 2902 else 2903 ret = 0; 2904 btrfs_free_path(path); 2905 return ret; 2906 } 2907 2908 /* 2909 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY 2910 * this function scans fs tree to find blocks reference the data extent 2911 */ 2912 static int find_data_references(struct reloc_control *rc, 2913 struct btrfs_key *extent_key, 2914 struct extent_buffer *leaf, 2915 struct btrfs_extent_data_ref *ref, 2916 struct rb_root *blocks) 2917 { 2918 struct btrfs_path *path; 2919 struct tree_block *block; 2920 struct btrfs_root *root; 2921 struct btrfs_file_extent_item *fi; 2922 struct rb_node *rb_node; 2923 struct btrfs_key key; 2924 u64 ref_root; 2925 u64 ref_objectid; 2926 u64 ref_offset; 2927 u32 ref_count; 2928 u32 nritems; 2929 int err = 0; 2930 int added = 0; 2931 int counted; 2932 int ret; 2933 2934 path = btrfs_alloc_path(); 2935 if (!path) 2936 return -ENOMEM; 2937 2938 ref_root = btrfs_extent_data_ref_root(leaf, ref); 2939 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref); 2940 ref_offset = btrfs_extent_data_ref_offset(leaf, ref); 2941 ref_count = btrfs_extent_data_ref_count(leaf, ref); 2942 2943 root = read_fs_root(rc->extent_root->fs_info, ref_root); 2944 if (IS_ERR(root)) { 2945 err = PTR_ERR(root); 2946 goto out; 2947 } 2948 2949 key.objectid = ref_objectid; 2950 key.offset = ref_offset; 2951 key.type = BTRFS_EXTENT_DATA_KEY; 2952 2953 path->search_commit_root = 1; 2954 path->skip_locking = 1; 2955 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 2956 if (ret < 0) { 2957 err = ret; 2958 goto out; 2959 } 2960 2961 leaf = path->nodes[0]; 2962 nritems = btrfs_header_nritems(leaf); 2963 /* 2964 * the references in tree blocks that use full backrefs 2965 * are not counted in 2966 */ 2967 if (block_use_full_backref(rc, leaf)) 2968 counted = 0; 2969 else 2970 counted = 1; 2971 rb_node = tree_search(blocks, leaf->start); 2972 if (rb_node) { 2973 if (counted) 2974 added = 1; 2975 else 2976 path->slots[0] = nritems; 2977 } 2978 2979 while (ref_count > 0) { 2980 while (path->slots[0] >= nritems) { 2981 ret = btrfs_next_leaf(root, path); 2982 if (ret < 0) { 2983 err = ret; 2984 goto out; 2985 } 2986 if (ret > 0) { 2987 WARN_ON(1); 2988 goto out; 2989 } 2990 2991 leaf = path->nodes[0]; 2992 nritems = btrfs_header_nritems(leaf); 2993 added = 0; 2994 2995 if (block_use_full_backref(rc, leaf)) 2996 counted = 0; 2997 else 2998 counted = 1; 2999 rb_node = tree_search(blocks, leaf->start); 3000 if (rb_node) { 3001 if (counted) 3002 added = 1; 3003 else 3004 path->slots[0] = nritems; 3005 } 3006 } 3007 3008 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 3009 if (key.objectid != ref_objectid || 3010 key.type != BTRFS_EXTENT_DATA_KEY) { 3011 WARN_ON(1); 3012 break; 3013 } 3014 3015 fi = btrfs_item_ptr(leaf, path->slots[0], 3016 struct btrfs_file_extent_item); 3017 3018 if (btrfs_file_extent_type(leaf, fi) == 3019 BTRFS_FILE_EXTENT_INLINE) 3020 goto next; 3021 3022 if (btrfs_file_extent_disk_bytenr(leaf, fi) != 3023 extent_key->objectid) 3024 goto next; 3025 3026 key.offset -= btrfs_file_extent_offset(leaf, fi); 3027 if (key.offset != ref_offset) 3028 goto next; 3029 3030 if (counted) 3031 ref_count--; 3032 if (added) 3033 goto next; 3034 3035 if (!tree_block_processed(leaf->start, leaf->len, rc)) { 3036 block = kmalloc(sizeof(*block), GFP_NOFS); 3037 if (!block) { 3038 err = -ENOMEM; 3039 break; 3040 } 3041 block->bytenr = leaf->start; 3042 btrfs_item_key_to_cpu(leaf, &block->key, 0); 3043 block->level = 0; 3044 block->key_ready = 1; 3045 rb_node = tree_insert(blocks, block->bytenr, 3046 &block->rb_node); 3047 BUG_ON(rb_node); 3048 } 3049 if (counted) 3050 added = 1; 3051 else 3052 path->slots[0] = nritems; 3053 next: 3054 path->slots[0]++; 3055 3056 } 3057 out: 3058 btrfs_free_path(path); 3059 return err; 3060 } 3061 3062 /* 3063 * hepler to find all tree blocks that reference a given data extent 3064 */ 3065 static noinline_for_stack 3066 int add_data_references(struct reloc_control *rc, 3067 struct btrfs_key *extent_key, 3068 struct btrfs_path *path, 3069 struct rb_root *blocks) 3070 { 3071 struct btrfs_key key; 3072 struct extent_buffer *eb; 3073 struct btrfs_extent_data_ref *dref; 3074 struct btrfs_extent_inline_ref *iref; 3075 unsigned long ptr; 3076 unsigned long end; 3077 u32 blocksize; 3078 int ret; 3079 int err = 0; 3080 3081 ret = get_new_location(rc->data_inode, NULL, extent_key->objectid, 3082 extent_key->offset); 3083 BUG_ON(ret < 0); 3084 if (ret > 0) { 3085 /* the relocated data is fragmented */ 3086 rc->extents_skipped++; 3087 btrfs_release_path(rc->extent_root, path); 3088 return 0; 3089 } 3090 3091 blocksize = btrfs_level_size(rc->extent_root, 0); 3092 3093 eb = path->nodes[0]; 3094 ptr = btrfs_item_ptr_offset(eb, path->slots[0]); 3095 end = ptr + btrfs_item_size_nr(eb, path->slots[0]); 3096 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 3097 if (ptr + sizeof(struct btrfs_extent_item_v0) == end) 3098 ptr = end; 3099 else 3100 #endif 3101 ptr += sizeof(struct btrfs_extent_item); 3102 3103 while (ptr < end) { 3104 iref = (struct btrfs_extent_inline_ref *)ptr; 3105 key.type = btrfs_extent_inline_ref_type(eb, iref); 3106 if (key.type == BTRFS_SHARED_DATA_REF_KEY) { 3107 key.offset = btrfs_extent_inline_ref_offset(eb, iref); 3108 ret = __add_tree_block(rc, key.offset, blocksize, 3109 blocks); 3110 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { 3111 dref = (struct btrfs_extent_data_ref *)(&iref->offset); 3112 ret = find_data_references(rc, extent_key, 3113 eb, dref, blocks); 3114 } else { 3115 BUG(); 3116 } 3117 ptr += btrfs_extent_inline_ref_size(key.type); 3118 } 3119 WARN_ON(ptr > end); 3120 3121 while (1) { 3122 cond_resched(); 3123 eb = path->nodes[0]; 3124 if (path->slots[0] >= btrfs_header_nritems(eb)) { 3125 ret = btrfs_next_leaf(rc->extent_root, path); 3126 if (ret < 0) { 3127 err = ret; 3128 break; 3129 } 3130 if (ret > 0) 3131 break; 3132 eb = path->nodes[0]; 3133 } 3134 3135 btrfs_item_key_to_cpu(eb, &key, path->slots[0]); 3136 if (key.objectid != extent_key->objectid) 3137 break; 3138 3139 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 3140 if (key.type == BTRFS_SHARED_DATA_REF_KEY || 3141 key.type == BTRFS_EXTENT_REF_V0_KEY) { 3142 #else 3143 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY); 3144 if (key.type == BTRFS_SHARED_DATA_REF_KEY) { 3145 #endif 3146 ret = __add_tree_block(rc, key.offset, blocksize, 3147 blocks); 3148 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) { 3149 dref = btrfs_item_ptr(eb, path->slots[0], 3150 struct btrfs_extent_data_ref); 3151 ret = find_data_references(rc, extent_key, 3152 eb, dref, blocks); 3153 } else { 3154 ret = 0; 3155 } 3156 if (ret) { 3157 err = ret; 3158 break; 3159 } 3160 path->slots[0]++; 3161 } 3162 btrfs_release_path(rc->extent_root, path); 3163 if (err) 3164 free_block_list(blocks); 3165 return err; 3166 } 3167 3168 /* 3169 * hepler to find next unprocessed extent 3170 */ 3171 static noinline_for_stack 3172 int find_next_extent(struct btrfs_trans_handle *trans, 3173 struct reloc_control *rc, struct btrfs_path *path) 3174 { 3175 struct btrfs_key key; 3176 struct extent_buffer *leaf; 3177 u64 start, end, last; 3178 int ret; 3179 3180 last = rc->block_group->key.objectid + rc->block_group->key.offset; 3181 while (1) { 3182 cond_resched(); 3183 if (rc->search_start >= last) { 3184 ret = 1; 3185 break; 3186 } 3187 3188 key.objectid = rc->search_start; 3189 key.type = BTRFS_EXTENT_ITEM_KEY; 3190 key.offset = 0; 3191 3192 path->search_commit_root = 1; 3193 path->skip_locking = 1; 3194 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 3195 0, 0); 3196 if (ret < 0) 3197 break; 3198 next: 3199 leaf = path->nodes[0]; 3200 if (path->slots[0] >= btrfs_header_nritems(leaf)) { 3201 ret = btrfs_next_leaf(rc->extent_root, path); 3202 if (ret != 0) 3203 break; 3204 leaf = path->nodes[0]; 3205 } 3206 3207 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 3208 if (key.objectid >= last) { 3209 ret = 1; 3210 break; 3211 } 3212 3213 if (key.type != BTRFS_EXTENT_ITEM_KEY || 3214 key.objectid + key.offset <= rc->search_start) { 3215 path->slots[0]++; 3216 goto next; 3217 } 3218 3219 ret = find_first_extent_bit(&rc->processed_blocks, 3220 key.objectid, &start, &end, 3221 EXTENT_DIRTY); 3222 3223 if (ret == 0 && start <= key.objectid) { 3224 btrfs_release_path(rc->extent_root, path); 3225 rc->search_start = end + 1; 3226 } else { 3227 rc->search_start = key.objectid + key.offset; 3228 return 0; 3229 } 3230 } 3231 btrfs_release_path(rc->extent_root, path); 3232 return ret; 3233 } 3234 3235 static void set_reloc_control(struct reloc_control *rc) 3236 { 3237 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; 3238 mutex_lock(&fs_info->trans_mutex); 3239 fs_info->reloc_ctl = rc; 3240 mutex_unlock(&fs_info->trans_mutex); 3241 } 3242 3243 static void unset_reloc_control(struct reloc_control *rc) 3244 { 3245 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info; 3246 mutex_lock(&fs_info->trans_mutex); 3247 fs_info->reloc_ctl = NULL; 3248 mutex_unlock(&fs_info->trans_mutex); 3249 } 3250 3251 static int check_extent_flags(u64 flags) 3252 { 3253 if ((flags & BTRFS_EXTENT_FLAG_DATA) && 3254 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) 3255 return 1; 3256 if (!(flags & BTRFS_EXTENT_FLAG_DATA) && 3257 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) 3258 return 1; 3259 if ((flags & BTRFS_EXTENT_FLAG_DATA) && 3260 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) 3261 return 1; 3262 return 0; 3263 } 3264 3265 3266 static noinline_for_stack int relocate_block_group(struct reloc_control *rc) 3267 { 3268 struct rb_root blocks = RB_ROOT; 3269 struct btrfs_key key; 3270 struct file_extent_cluster *cluster; 3271 struct btrfs_trans_handle *trans = NULL; 3272 struct btrfs_path *path; 3273 struct btrfs_extent_item *ei; 3274 unsigned long nr; 3275 u64 flags; 3276 u32 item_size; 3277 int ret; 3278 int err = 0; 3279 3280 cluster = kzalloc(sizeof(*cluster), GFP_NOFS); 3281 if (!cluster) 3282 return -ENOMEM; 3283 3284 path = btrfs_alloc_path(); 3285 if (!path) { 3286 kfree(cluster); 3287 return -ENOMEM; 3288 } 3289 3290 rc->extents_found = 0; 3291 rc->extents_skipped = 0; 3292 3293 rc->search_start = rc->block_group->key.objectid; 3294 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY, 3295 GFP_NOFS); 3296 3297 rc->create_reloc_root = 1; 3298 set_reloc_control(rc); 3299 3300 trans = btrfs_start_transaction(rc->extent_root, 1); 3301 btrfs_commit_transaction(trans, rc->extent_root); 3302 3303 while (1) { 3304 trans = btrfs_start_transaction(rc->extent_root, 1); 3305 3306 ret = find_next_extent(trans, rc, path); 3307 if (ret < 0) 3308 err = ret; 3309 if (ret != 0) 3310 break; 3311 3312 rc->extents_found++; 3313 3314 ei = btrfs_item_ptr(path->nodes[0], path->slots[0], 3315 struct btrfs_extent_item); 3316 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 3317 item_size = btrfs_item_size_nr(path->nodes[0], 3318 path->slots[0]); 3319 if (item_size >= sizeof(*ei)) { 3320 flags = btrfs_extent_flags(path->nodes[0], ei); 3321 ret = check_extent_flags(flags); 3322 BUG_ON(ret); 3323 3324 } else { 3325 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 3326 u64 ref_owner; 3327 int path_change = 0; 3328 3329 BUG_ON(item_size != 3330 sizeof(struct btrfs_extent_item_v0)); 3331 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner, 3332 &path_change); 3333 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID) 3334 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK; 3335 else 3336 flags = BTRFS_EXTENT_FLAG_DATA; 3337 3338 if (path_change) { 3339 btrfs_release_path(rc->extent_root, path); 3340 3341 path->search_commit_root = 1; 3342 path->skip_locking = 1; 3343 ret = btrfs_search_slot(NULL, rc->extent_root, 3344 &key, path, 0, 0); 3345 if (ret < 0) { 3346 err = ret; 3347 break; 3348 } 3349 BUG_ON(ret > 0); 3350 } 3351 #else 3352 BUG(); 3353 #endif 3354 } 3355 3356 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { 3357 ret = add_tree_block(rc, &key, path, &blocks); 3358 } else if (rc->stage == UPDATE_DATA_PTRS && 3359 (flags & BTRFS_EXTENT_FLAG_DATA)) { 3360 ret = add_data_references(rc, &key, path, &blocks); 3361 } else { 3362 btrfs_release_path(rc->extent_root, path); 3363 ret = 0; 3364 } 3365 if (ret < 0) { 3366 err = 0; 3367 break; 3368 } 3369 3370 if (!RB_EMPTY_ROOT(&blocks)) { 3371 ret = relocate_tree_blocks(trans, rc, &blocks); 3372 if (ret < 0) { 3373 err = ret; 3374 break; 3375 } 3376 } 3377 3378 nr = trans->blocks_used; 3379 btrfs_end_transaction(trans, rc->extent_root); 3380 trans = NULL; 3381 btrfs_btree_balance_dirty(rc->extent_root, nr); 3382 3383 if (rc->stage == MOVE_DATA_EXTENTS && 3384 (flags & BTRFS_EXTENT_FLAG_DATA)) { 3385 rc->found_file_extent = 1; 3386 ret = relocate_data_extent(rc->data_inode, 3387 &key, cluster); 3388 if (ret < 0) { 3389 err = ret; 3390 break; 3391 } 3392 } 3393 } 3394 btrfs_free_path(path); 3395 3396 if (trans) { 3397 nr = trans->blocks_used; 3398 btrfs_end_transaction(trans, rc->extent_root); 3399 btrfs_btree_balance_dirty(rc->extent_root, nr); 3400 } 3401 3402 if (!err) { 3403 ret = relocate_file_extent_cluster(rc->data_inode, cluster); 3404 if (ret < 0) 3405 err = ret; 3406 } 3407 3408 kfree(cluster); 3409 3410 rc->create_reloc_root = 0; 3411 smp_mb(); 3412 3413 if (rc->extents_found > 0) { 3414 trans = btrfs_start_transaction(rc->extent_root, 1); 3415 btrfs_commit_transaction(trans, rc->extent_root); 3416 } 3417 3418 merge_reloc_roots(rc); 3419 3420 unset_reloc_control(rc); 3421 3422 /* get rid of pinned extents */ 3423 trans = btrfs_start_transaction(rc->extent_root, 1); 3424 btrfs_commit_transaction(trans, rc->extent_root); 3425 3426 return err; 3427 } 3428 3429 static int __insert_orphan_inode(struct btrfs_trans_handle *trans, 3430 struct btrfs_root *root, u64 objectid) 3431 { 3432 struct btrfs_path *path; 3433 struct btrfs_inode_item *item; 3434 struct extent_buffer *leaf; 3435 int ret; 3436 3437 path = btrfs_alloc_path(); 3438 if (!path) 3439 return -ENOMEM; 3440 3441 ret = btrfs_insert_empty_inode(trans, root, path, objectid); 3442 if (ret) 3443 goto out; 3444 3445 leaf = path->nodes[0]; 3446 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item); 3447 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item)); 3448 btrfs_set_inode_generation(leaf, item, 1); 3449 btrfs_set_inode_size(leaf, item, 0); 3450 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600); 3451 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS); 3452 btrfs_mark_buffer_dirty(leaf); 3453 btrfs_release_path(root, path); 3454 out: 3455 btrfs_free_path(path); 3456 return ret; 3457 } 3458 3459 /* 3460 * helper to create inode for data relocation. 3461 * the inode is in data relocation tree and its link count is 0 3462 */ 3463 static struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info, 3464 struct btrfs_block_group_cache *group) 3465 { 3466 struct inode *inode = NULL; 3467 struct btrfs_trans_handle *trans; 3468 struct btrfs_root *root; 3469 struct btrfs_key key; 3470 unsigned long nr; 3471 u64 objectid = BTRFS_FIRST_FREE_OBJECTID; 3472 int err = 0; 3473 3474 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID); 3475 if (IS_ERR(root)) 3476 return ERR_CAST(root); 3477 3478 trans = btrfs_start_transaction(root, 1); 3479 BUG_ON(!trans); 3480 3481 err = btrfs_find_free_objectid(trans, root, objectid, &objectid); 3482 if (err) 3483 goto out; 3484 3485 err = __insert_orphan_inode(trans, root, objectid); 3486 BUG_ON(err); 3487 3488 key.objectid = objectid; 3489 key.type = BTRFS_INODE_ITEM_KEY; 3490 key.offset = 0; 3491 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL); 3492 BUG_ON(IS_ERR(inode) || is_bad_inode(inode)); 3493 BTRFS_I(inode)->index_cnt = group->key.objectid; 3494 3495 err = btrfs_orphan_add(trans, inode); 3496 out: 3497 nr = trans->blocks_used; 3498 btrfs_end_transaction(trans, root); 3499 3500 btrfs_btree_balance_dirty(root, nr); 3501 if (err) { 3502 if (inode) 3503 iput(inode); 3504 inode = ERR_PTR(err); 3505 } 3506 return inode; 3507 } 3508 3509 /* 3510 * function to relocate all extents in a block group. 3511 */ 3512 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start) 3513 { 3514 struct btrfs_fs_info *fs_info = extent_root->fs_info; 3515 struct reloc_control *rc; 3516 int ret; 3517 int err = 0; 3518 3519 rc = kzalloc(sizeof(*rc), GFP_NOFS); 3520 if (!rc) 3521 return -ENOMEM; 3522 3523 mapping_tree_init(&rc->reloc_root_tree); 3524 extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS); 3525 INIT_LIST_HEAD(&rc->reloc_roots); 3526 3527 rc->block_group = btrfs_lookup_block_group(fs_info, group_start); 3528 BUG_ON(!rc->block_group); 3529 3530 btrfs_init_workers(&rc->workers, "relocate", 3531 fs_info->thread_pool_size, NULL); 3532 3533 rc->extent_root = extent_root; 3534 btrfs_prepare_block_group_relocation(extent_root, rc->block_group); 3535 3536 rc->data_inode = create_reloc_inode(fs_info, rc->block_group); 3537 if (IS_ERR(rc->data_inode)) { 3538 err = PTR_ERR(rc->data_inode); 3539 rc->data_inode = NULL; 3540 goto out; 3541 } 3542 3543 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n", 3544 (unsigned long long)rc->block_group->key.objectid, 3545 (unsigned long long)rc->block_group->flags); 3546 3547 btrfs_start_delalloc_inodes(fs_info->tree_root, 0); 3548 btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0); 3549 3550 while (1) { 3551 rc->extents_found = 0; 3552 rc->extents_skipped = 0; 3553 3554 mutex_lock(&fs_info->cleaner_mutex); 3555 3556 btrfs_clean_old_snapshots(fs_info->tree_root); 3557 ret = relocate_block_group(rc); 3558 3559 mutex_unlock(&fs_info->cleaner_mutex); 3560 if (ret < 0) { 3561 err = ret; 3562 break; 3563 } 3564 3565 if (rc->extents_found == 0) 3566 break; 3567 3568 printk(KERN_INFO "btrfs: found %llu extents\n", 3569 (unsigned long long)rc->extents_found); 3570 3571 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) { 3572 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1); 3573 invalidate_mapping_pages(rc->data_inode->i_mapping, 3574 0, -1); 3575 rc->stage = UPDATE_DATA_PTRS; 3576 } else if (rc->stage == UPDATE_DATA_PTRS && 3577 rc->extents_skipped >= rc->extents_found) { 3578 iput(rc->data_inode); 3579 rc->data_inode = create_reloc_inode(fs_info, 3580 rc->block_group); 3581 if (IS_ERR(rc->data_inode)) { 3582 err = PTR_ERR(rc->data_inode); 3583 rc->data_inode = NULL; 3584 break; 3585 } 3586 rc->stage = MOVE_DATA_EXTENTS; 3587 rc->found_file_extent = 0; 3588 } 3589 } 3590 3591 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping, 3592 rc->block_group->key.objectid, 3593 rc->block_group->key.objectid + 3594 rc->block_group->key.offset - 1); 3595 3596 WARN_ON(rc->block_group->pinned > 0); 3597 WARN_ON(rc->block_group->reserved > 0); 3598 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0); 3599 out: 3600 iput(rc->data_inode); 3601 btrfs_stop_workers(&rc->workers); 3602 btrfs_put_block_group(rc->block_group); 3603 kfree(rc); 3604 return err; 3605 } 3606 3607 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root) 3608 { 3609 struct btrfs_trans_handle *trans; 3610 int ret; 3611 3612 trans = btrfs_start_transaction(root->fs_info->tree_root, 1); 3613 3614 memset(&root->root_item.drop_progress, 0, 3615 sizeof(root->root_item.drop_progress)); 3616 root->root_item.drop_level = 0; 3617 btrfs_set_root_refs(&root->root_item, 0); 3618 ret = btrfs_update_root(trans, root->fs_info->tree_root, 3619 &root->root_key, &root->root_item); 3620 BUG_ON(ret); 3621 3622 ret = btrfs_end_transaction(trans, root->fs_info->tree_root); 3623 BUG_ON(ret); 3624 return 0; 3625 } 3626 3627 /* 3628 * recover relocation interrupted by system crash. 3629 * 3630 * this function resumes merging reloc trees with corresponding fs trees. 3631 * this is important for keeping the sharing of tree blocks 3632 */ 3633 int btrfs_recover_relocation(struct btrfs_root *root) 3634 { 3635 LIST_HEAD(reloc_roots); 3636 struct btrfs_key key; 3637 struct btrfs_root *fs_root; 3638 struct btrfs_root *reloc_root; 3639 struct btrfs_path *path; 3640 struct extent_buffer *leaf; 3641 struct reloc_control *rc = NULL; 3642 struct btrfs_trans_handle *trans; 3643 int ret; 3644 int err = 0; 3645 3646 path = btrfs_alloc_path(); 3647 if (!path) 3648 return -ENOMEM; 3649 3650 key.objectid = BTRFS_TREE_RELOC_OBJECTID; 3651 key.type = BTRFS_ROOT_ITEM_KEY; 3652 key.offset = (u64)-1; 3653 3654 while (1) { 3655 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key, 3656 path, 0, 0); 3657 if (ret < 0) { 3658 err = ret; 3659 goto out; 3660 } 3661 if (ret > 0) { 3662 if (path->slots[0] == 0) 3663 break; 3664 path->slots[0]--; 3665 } 3666 leaf = path->nodes[0]; 3667 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 3668 btrfs_release_path(root->fs_info->tree_root, path); 3669 3670 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID || 3671 key.type != BTRFS_ROOT_ITEM_KEY) 3672 break; 3673 3674 reloc_root = btrfs_read_fs_root_no_radix(root, &key); 3675 if (IS_ERR(reloc_root)) { 3676 err = PTR_ERR(reloc_root); 3677 goto out; 3678 } 3679 3680 list_add(&reloc_root->root_list, &reloc_roots); 3681 3682 if (btrfs_root_refs(&reloc_root->root_item) > 0) { 3683 fs_root = read_fs_root(root->fs_info, 3684 reloc_root->root_key.offset); 3685 if (IS_ERR(fs_root)) { 3686 ret = PTR_ERR(fs_root); 3687 if (ret != -ENOENT) { 3688 err = ret; 3689 goto out; 3690 } 3691 mark_garbage_root(reloc_root); 3692 } 3693 } 3694 3695 if (key.offset == 0) 3696 break; 3697 3698 key.offset--; 3699 } 3700 btrfs_release_path(root->fs_info->tree_root, path); 3701 3702 if (list_empty(&reloc_roots)) 3703 goto out; 3704 3705 rc = kzalloc(sizeof(*rc), GFP_NOFS); 3706 if (!rc) { 3707 err = -ENOMEM; 3708 goto out; 3709 } 3710 3711 mapping_tree_init(&rc->reloc_root_tree); 3712 INIT_LIST_HEAD(&rc->reloc_roots); 3713 btrfs_init_workers(&rc->workers, "relocate", 3714 root->fs_info->thread_pool_size, NULL); 3715 rc->extent_root = root->fs_info->extent_root; 3716 3717 set_reloc_control(rc); 3718 3719 while (!list_empty(&reloc_roots)) { 3720 reloc_root = list_entry(reloc_roots.next, 3721 struct btrfs_root, root_list); 3722 list_del(&reloc_root->root_list); 3723 3724 if (btrfs_root_refs(&reloc_root->root_item) == 0) { 3725 list_add_tail(&reloc_root->root_list, 3726 &rc->reloc_roots); 3727 continue; 3728 } 3729 3730 fs_root = read_fs_root(root->fs_info, 3731 reloc_root->root_key.offset); 3732 BUG_ON(IS_ERR(fs_root)); 3733 3734 __add_reloc_root(reloc_root); 3735 fs_root->reloc_root = reloc_root; 3736 } 3737 3738 trans = btrfs_start_transaction(rc->extent_root, 1); 3739 btrfs_commit_transaction(trans, rc->extent_root); 3740 3741 merge_reloc_roots(rc); 3742 3743 unset_reloc_control(rc); 3744 3745 trans = btrfs_start_transaction(rc->extent_root, 1); 3746 btrfs_commit_transaction(trans, rc->extent_root); 3747 out: 3748 if (rc) { 3749 btrfs_stop_workers(&rc->workers); 3750 kfree(rc); 3751 } 3752 while (!list_empty(&reloc_roots)) { 3753 reloc_root = list_entry(reloc_roots.next, 3754 struct btrfs_root, root_list); 3755 list_del(&reloc_root->root_list); 3756 free_extent_buffer(reloc_root->node); 3757 free_extent_buffer(reloc_root->commit_root); 3758 kfree(reloc_root); 3759 } 3760 btrfs_free_path(path); 3761 3762 if (err == 0) { 3763 /* cleanup orphan inode in data relocation tree */ 3764 fs_root = read_fs_root(root->fs_info, 3765 BTRFS_DATA_RELOC_TREE_OBJECTID); 3766 if (IS_ERR(fs_root)) 3767 err = PTR_ERR(fs_root); 3768 else 3769 btrfs_orphan_cleanup(fs_root); 3770 } 3771 return err; 3772 } 3773 3774 /* 3775 * helper to add ordered checksum for data relocation. 3776 * 3777 * cloning checksum properly handles the nodatasum extents. 3778 * it also saves CPU time to re-calculate the checksum. 3779 */ 3780 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len) 3781 { 3782 struct btrfs_ordered_sum *sums; 3783 struct btrfs_sector_sum *sector_sum; 3784 struct btrfs_ordered_extent *ordered; 3785 struct btrfs_root *root = BTRFS_I(inode)->root; 3786 size_t offset; 3787 int ret; 3788 u64 disk_bytenr; 3789 LIST_HEAD(list); 3790 3791 ordered = btrfs_lookup_ordered_extent(inode, file_pos); 3792 BUG_ON(ordered->file_offset != file_pos || ordered->len != len); 3793 3794 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt; 3795 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr, 3796 disk_bytenr + len - 1, &list); 3797 3798 while (!list_empty(&list)) { 3799 sums = list_entry(list.next, struct btrfs_ordered_sum, list); 3800 list_del_init(&sums->list); 3801 3802 sector_sum = sums->sums; 3803 sums->bytenr = ordered->start; 3804 3805 offset = 0; 3806 while (offset < sums->len) { 3807 sector_sum->bytenr += ordered->start - disk_bytenr; 3808 sector_sum++; 3809 offset += root->sectorsize; 3810 } 3811 3812 btrfs_add_ordered_sum(inode, ordered, sums); 3813 } 3814 btrfs_put_ordered_extent(ordered); 3815 return 0; 3816 } 3817