1 /* 2 * Copyright (C) 2011 STRATO. 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/vmalloc.h> 20 #include "ctree.h" 21 #include "disk-io.h" 22 #include "backref.h" 23 #include "ulist.h" 24 #include "transaction.h" 25 #include "delayed-ref.h" 26 #include "locking.h" 27 28 struct extent_inode_elem { 29 u64 inum; 30 u64 offset; 31 struct extent_inode_elem *next; 32 }; 33 34 static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb, 35 struct btrfs_file_extent_item *fi, 36 u64 extent_item_pos, 37 struct extent_inode_elem **eie) 38 { 39 u64 offset = 0; 40 struct extent_inode_elem *e; 41 42 if (!btrfs_file_extent_compression(eb, fi) && 43 !btrfs_file_extent_encryption(eb, fi) && 44 !btrfs_file_extent_other_encoding(eb, fi)) { 45 u64 data_offset; 46 u64 data_len; 47 48 data_offset = btrfs_file_extent_offset(eb, fi); 49 data_len = btrfs_file_extent_num_bytes(eb, fi); 50 51 if (extent_item_pos < data_offset || 52 extent_item_pos >= data_offset + data_len) 53 return 1; 54 offset = extent_item_pos - data_offset; 55 } 56 57 e = kmalloc(sizeof(*e), GFP_NOFS); 58 if (!e) 59 return -ENOMEM; 60 61 e->next = *eie; 62 e->inum = key->objectid; 63 e->offset = key->offset + offset; 64 *eie = e; 65 66 return 0; 67 } 68 69 static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte, 70 u64 extent_item_pos, 71 struct extent_inode_elem **eie) 72 { 73 u64 disk_byte; 74 struct btrfs_key key; 75 struct btrfs_file_extent_item *fi; 76 int slot; 77 int nritems; 78 int extent_type; 79 int ret; 80 81 /* 82 * from the shared data ref, we only have the leaf but we need 83 * the key. thus, we must look into all items and see that we 84 * find one (some) with a reference to our extent item. 85 */ 86 nritems = btrfs_header_nritems(eb); 87 for (slot = 0; slot < nritems; ++slot) { 88 btrfs_item_key_to_cpu(eb, &key, slot); 89 if (key.type != BTRFS_EXTENT_DATA_KEY) 90 continue; 91 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); 92 extent_type = btrfs_file_extent_type(eb, fi); 93 if (extent_type == BTRFS_FILE_EXTENT_INLINE) 94 continue; 95 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */ 96 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); 97 if (disk_byte != wanted_disk_byte) 98 continue; 99 100 ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie); 101 if (ret < 0) 102 return ret; 103 } 104 105 return 0; 106 } 107 108 /* 109 * this structure records all encountered refs on the way up to the root 110 */ 111 struct __prelim_ref { 112 struct list_head list; 113 u64 root_id; 114 struct btrfs_key key_for_search; 115 int level; 116 int count; 117 struct extent_inode_elem *inode_list; 118 u64 parent; 119 u64 wanted_disk_byte; 120 }; 121 122 /* 123 * the rules for all callers of this function are: 124 * - obtaining the parent is the goal 125 * - if you add a key, you must know that it is a correct key 126 * - if you cannot add the parent or a correct key, then we will look into the 127 * block later to set a correct key 128 * 129 * delayed refs 130 * ============ 131 * backref type | shared | indirect | shared | indirect 132 * information | tree | tree | data | data 133 * --------------------+--------+----------+--------+---------- 134 * parent logical | y | - | - | - 135 * key to resolve | - | y | y | y 136 * tree block logical | - | - | - | - 137 * root for resolving | y | y | y | y 138 * 139 * - column 1: we've the parent -> done 140 * - column 2, 3, 4: we use the key to find the parent 141 * 142 * on disk refs (inline or keyed) 143 * ============================== 144 * backref type | shared | indirect | shared | indirect 145 * information | tree | tree | data | data 146 * --------------------+--------+----------+--------+---------- 147 * parent logical | y | - | y | - 148 * key to resolve | - | - | - | y 149 * tree block logical | y | y | y | y 150 * root for resolving | - | y | y | y 151 * 152 * - column 1, 3: we've the parent -> done 153 * - column 2: we take the first key from the block to find the parent 154 * (see __add_missing_keys) 155 * - column 4: we use the key to find the parent 156 * 157 * additional information that's available but not required to find the parent 158 * block might help in merging entries to gain some speed. 159 */ 160 161 static int __add_prelim_ref(struct list_head *head, u64 root_id, 162 struct btrfs_key *key, int level, 163 u64 parent, u64 wanted_disk_byte, int count) 164 { 165 struct __prelim_ref *ref; 166 167 /* in case we're adding delayed refs, we're holding the refs spinlock */ 168 ref = kmalloc(sizeof(*ref), GFP_ATOMIC); 169 if (!ref) 170 return -ENOMEM; 171 172 ref->root_id = root_id; 173 if (key) 174 ref->key_for_search = *key; 175 else 176 memset(&ref->key_for_search, 0, sizeof(ref->key_for_search)); 177 178 ref->inode_list = NULL; 179 ref->level = level; 180 ref->count = count; 181 ref->parent = parent; 182 ref->wanted_disk_byte = wanted_disk_byte; 183 list_add_tail(&ref->list, head); 184 185 return 0; 186 } 187 188 static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, 189 struct ulist *parents, int level, 190 struct btrfs_key *key_for_search, u64 time_seq, 191 u64 wanted_disk_byte, 192 const u64 *extent_item_pos) 193 { 194 int ret = 0; 195 int slot; 196 struct extent_buffer *eb; 197 struct btrfs_key key; 198 struct btrfs_file_extent_item *fi; 199 struct extent_inode_elem *eie = NULL, *old = NULL; 200 u64 disk_byte; 201 202 if (level != 0) { 203 eb = path->nodes[level]; 204 ret = ulist_add(parents, eb->start, 0, GFP_NOFS); 205 if (ret < 0) 206 return ret; 207 return 0; 208 } 209 210 /* 211 * We normally enter this function with the path already pointing to 212 * the first item to check. But sometimes, we may enter it with 213 * slot==nritems. In that case, go to the next leaf before we continue. 214 */ 215 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) 216 ret = btrfs_next_old_leaf(root, path, time_seq); 217 218 while (!ret) { 219 eb = path->nodes[0]; 220 slot = path->slots[0]; 221 222 btrfs_item_key_to_cpu(eb, &key, slot); 223 224 if (key.objectid != key_for_search->objectid || 225 key.type != BTRFS_EXTENT_DATA_KEY) 226 break; 227 228 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); 229 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); 230 231 if (disk_byte == wanted_disk_byte) { 232 eie = NULL; 233 old = NULL; 234 if (extent_item_pos) { 235 ret = check_extent_in_eb(&key, eb, fi, 236 *extent_item_pos, 237 &eie); 238 if (ret < 0) 239 break; 240 } 241 if (ret > 0) 242 goto next; 243 ret = ulist_add_merge(parents, eb->start, 244 (uintptr_t)eie, 245 (u64 *)&old, GFP_NOFS); 246 if (ret < 0) 247 break; 248 if (!ret && extent_item_pos) { 249 while (old->next) 250 old = old->next; 251 old->next = eie; 252 } 253 } 254 next: 255 ret = btrfs_next_old_item(root, path, time_seq); 256 } 257 258 if (ret > 0) 259 ret = 0; 260 return ret; 261 } 262 263 /* 264 * resolve an indirect backref in the form (root_id, key, level) 265 * to a logical address 266 */ 267 static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, 268 struct btrfs_path *path, u64 time_seq, 269 struct __prelim_ref *ref, 270 struct ulist *parents, 271 const u64 *extent_item_pos) 272 { 273 struct btrfs_root *root; 274 struct btrfs_key root_key; 275 struct extent_buffer *eb; 276 int ret = 0; 277 int root_level; 278 int level = ref->level; 279 280 root_key.objectid = ref->root_id; 281 root_key.type = BTRFS_ROOT_ITEM_KEY; 282 root_key.offset = (u64)-1; 283 root = btrfs_read_fs_root_no_name(fs_info, &root_key); 284 if (IS_ERR(root)) { 285 ret = PTR_ERR(root); 286 goto out; 287 } 288 289 root_level = btrfs_old_root_level(root, time_seq); 290 291 if (root_level + 1 == level) 292 goto out; 293 294 path->lowest_level = level; 295 ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq); 296 pr_debug("search slot in root %llu (level %d, ref count %d) returned " 297 "%d for key (%llu %u %llu)\n", 298 (unsigned long long)ref->root_id, level, ref->count, ret, 299 (unsigned long long)ref->key_for_search.objectid, 300 ref->key_for_search.type, 301 (unsigned long long)ref->key_for_search.offset); 302 if (ret < 0) 303 goto out; 304 305 eb = path->nodes[level]; 306 while (!eb) { 307 if (!level) { 308 WARN_ON(1); 309 ret = 1; 310 goto out; 311 } 312 level--; 313 eb = path->nodes[level]; 314 } 315 316 ret = add_all_parents(root, path, parents, level, &ref->key_for_search, 317 time_seq, ref->wanted_disk_byte, 318 extent_item_pos); 319 out: 320 path->lowest_level = 0; 321 btrfs_release_path(path); 322 return ret; 323 } 324 325 /* 326 * resolve all indirect backrefs from the list 327 */ 328 static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info, 329 struct btrfs_path *path, u64 time_seq, 330 struct list_head *head, 331 const u64 *extent_item_pos) 332 { 333 int err; 334 int ret = 0; 335 struct __prelim_ref *ref; 336 struct __prelim_ref *ref_safe; 337 struct __prelim_ref *new_ref; 338 struct ulist *parents; 339 struct ulist_node *node; 340 struct ulist_iterator uiter; 341 342 parents = ulist_alloc(GFP_NOFS); 343 if (!parents) 344 return -ENOMEM; 345 346 /* 347 * _safe allows us to insert directly after the current item without 348 * iterating over the newly inserted items. 349 * we're also allowed to re-assign ref during iteration. 350 */ 351 list_for_each_entry_safe(ref, ref_safe, head, list) { 352 if (ref->parent) /* already direct */ 353 continue; 354 if (ref->count == 0) 355 continue; 356 err = __resolve_indirect_ref(fs_info, path, time_seq, ref, 357 parents, extent_item_pos); 358 if (err == -ENOMEM) 359 goto out; 360 if (err) 361 continue; 362 363 /* we put the first parent into the ref at hand */ 364 ULIST_ITER_INIT(&uiter); 365 node = ulist_next(parents, &uiter); 366 ref->parent = node ? node->val : 0; 367 ref->inode_list = node ? 368 (struct extent_inode_elem *)(uintptr_t)node->aux : 0; 369 370 /* additional parents require new refs being added here */ 371 while ((node = ulist_next(parents, &uiter))) { 372 new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS); 373 if (!new_ref) { 374 ret = -ENOMEM; 375 goto out; 376 } 377 memcpy(new_ref, ref, sizeof(*ref)); 378 new_ref->parent = node->val; 379 new_ref->inode_list = (struct extent_inode_elem *) 380 (uintptr_t)node->aux; 381 list_add(&new_ref->list, &ref->list); 382 } 383 ulist_reinit(parents); 384 } 385 out: 386 ulist_free(parents); 387 return ret; 388 } 389 390 static inline int ref_for_same_block(struct __prelim_ref *ref1, 391 struct __prelim_ref *ref2) 392 { 393 if (ref1->level != ref2->level) 394 return 0; 395 if (ref1->root_id != ref2->root_id) 396 return 0; 397 if (ref1->key_for_search.type != ref2->key_for_search.type) 398 return 0; 399 if (ref1->key_for_search.objectid != ref2->key_for_search.objectid) 400 return 0; 401 if (ref1->key_for_search.offset != ref2->key_for_search.offset) 402 return 0; 403 if (ref1->parent != ref2->parent) 404 return 0; 405 406 return 1; 407 } 408 409 /* 410 * read tree blocks and add keys where required. 411 */ 412 static int __add_missing_keys(struct btrfs_fs_info *fs_info, 413 struct list_head *head) 414 { 415 struct list_head *pos; 416 struct extent_buffer *eb; 417 418 list_for_each(pos, head) { 419 struct __prelim_ref *ref; 420 ref = list_entry(pos, struct __prelim_ref, list); 421 422 if (ref->parent) 423 continue; 424 if (ref->key_for_search.type) 425 continue; 426 BUG_ON(!ref->wanted_disk_byte); 427 eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte, 428 fs_info->tree_root->leafsize, 0); 429 if (!eb || !extent_buffer_uptodate(eb)) { 430 free_extent_buffer(eb); 431 return -EIO; 432 } 433 btrfs_tree_read_lock(eb); 434 if (btrfs_header_level(eb) == 0) 435 btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0); 436 else 437 btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0); 438 btrfs_tree_read_unlock(eb); 439 free_extent_buffer(eb); 440 } 441 return 0; 442 } 443 444 /* 445 * merge two lists of backrefs and adjust counts accordingly 446 * 447 * mode = 1: merge identical keys, if key is set 448 * FIXME: if we add more keys in __add_prelim_ref, we can merge more here. 449 * additionally, we could even add a key range for the blocks we 450 * looked into to merge even more (-> replace unresolved refs by those 451 * having a parent). 452 * mode = 2: merge identical parents 453 */ 454 static void __merge_refs(struct list_head *head, int mode) 455 { 456 struct list_head *pos1; 457 458 list_for_each(pos1, head) { 459 struct list_head *n2; 460 struct list_head *pos2; 461 struct __prelim_ref *ref1; 462 463 ref1 = list_entry(pos1, struct __prelim_ref, list); 464 465 for (pos2 = pos1->next, n2 = pos2->next; pos2 != head; 466 pos2 = n2, n2 = pos2->next) { 467 struct __prelim_ref *ref2; 468 struct __prelim_ref *xchg; 469 struct extent_inode_elem *eie; 470 471 ref2 = list_entry(pos2, struct __prelim_ref, list); 472 473 if (mode == 1) { 474 if (!ref_for_same_block(ref1, ref2)) 475 continue; 476 if (!ref1->parent && ref2->parent) { 477 xchg = ref1; 478 ref1 = ref2; 479 ref2 = xchg; 480 } 481 } else { 482 if (ref1->parent != ref2->parent) 483 continue; 484 } 485 486 eie = ref1->inode_list; 487 while (eie && eie->next) 488 eie = eie->next; 489 if (eie) 490 eie->next = ref2->inode_list; 491 else 492 ref1->inode_list = ref2->inode_list; 493 ref1->count += ref2->count; 494 495 list_del(&ref2->list); 496 kfree(ref2); 497 } 498 499 } 500 } 501 502 /* 503 * add all currently queued delayed refs from this head whose seq nr is 504 * smaller or equal that seq to the list 505 */ 506 static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq, 507 struct list_head *prefs) 508 { 509 struct btrfs_delayed_extent_op *extent_op = head->extent_op; 510 struct rb_node *n = &head->node.rb_node; 511 struct btrfs_key key; 512 struct btrfs_key op_key = {0}; 513 int sgn; 514 int ret = 0; 515 516 if (extent_op && extent_op->update_key) 517 btrfs_disk_key_to_cpu(&op_key, &extent_op->key); 518 519 while ((n = rb_prev(n))) { 520 struct btrfs_delayed_ref_node *node; 521 node = rb_entry(n, struct btrfs_delayed_ref_node, 522 rb_node); 523 if (node->bytenr != head->node.bytenr) 524 break; 525 WARN_ON(node->is_head); 526 527 if (node->seq > seq) 528 continue; 529 530 switch (node->action) { 531 case BTRFS_ADD_DELAYED_EXTENT: 532 case BTRFS_UPDATE_DELAYED_HEAD: 533 WARN_ON(1); 534 continue; 535 case BTRFS_ADD_DELAYED_REF: 536 sgn = 1; 537 break; 538 case BTRFS_DROP_DELAYED_REF: 539 sgn = -1; 540 break; 541 default: 542 BUG_ON(1); 543 } 544 switch (node->type) { 545 case BTRFS_TREE_BLOCK_REF_KEY: { 546 struct btrfs_delayed_tree_ref *ref; 547 548 ref = btrfs_delayed_node_to_tree_ref(node); 549 ret = __add_prelim_ref(prefs, ref->root, &op_key, 550 ref->level + 1, 0, node->bytenr, 551 node->ref_mod * sgn); 552 break; 553 } 554 case BTRFS_SHARED_BLOCK_REF_KEY: { 555 struct btrfs_delayed_tree_ref *ref; 556 557 ref = btrfs_delayed_node_to_tree_ref(node); 558 ret = __add_prelim_ref(prefs, ref->root, NULL, 559 ref->level + 1, ref->parent, 560 node->bytenr, 561 node->ref_mod * sgn); 562 break; 563 } 564 case BTRFS_EXTENT_DATA_REF_KEY: { 565 struct btrfs_delayed_data_ref *ref; 566 ref = btrfs_delayed_node_to_data_ref(node); 567 568 key.objectid = ref->objectid; 569 key.type = BTRFS_EXTENT_DATA_KEY; 570 key.offset = ref->offset; 571 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0, 572 node->bytenr, 573 node->ref_mod * sgn); 574 break; 575 } 576 case BTRFS_SHARED_DATA_REF_KEY: { 577 struct btrfs_delayed_data_ref *ref; 578 579 ref = btrfs_delayed_node_to_data_ref(node); 580 581 key.objectid = ref->objectid; 582 key.type = BTRFS_EXTENT_DATA_KEY; 583 key.offset = ref->offset; 584 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 585 ref->parent, node->bytenr, 586 node->ref_mod * sgn); 587 break; 588 } 589 default: 590 WARN_ON(1); 591 } 592 if (ret) 593 return ret; 594 } 595 596 return 0; 597 } 598 599 /* 600 * add all inline backrefs for bytenr to the list 601 */ 602 static int __add_inline_refs(struct btrfs_fs_info *fs_info, 603 struct btrfs_path *path, u64 bytenr, 604 int *info_level, struct list_head *prefs) 605 { 606 int ret = 0; 607 int slot; 608 struct extent_buffer *leaf; 609 struct btrfs_key key; 610 struct btrfs_key found_key; 611 unsigned long ptr; 612 unsigned long end; 613 struct btrfs_extent_item *ei; 614 u64 flags; 615 u64 item_size; 616 617 /* 618 * enumerate all inline refs 619 */ 620 leaf = path->nodes[0]; 621 slot = path->slots[0]; 622 623 item_size = btrfs_item_size_nr(leaf, slot); 624 BUG_ON(item_size < sizeof(*ei)); 625 626 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); 627 flags = btrfs_extent_flags(leaf, ei); 628 btrfs_item_key_to_cpu(leaf, &found_key, slot); 629 630 ptr = (unsigned long)(ei + 1); 631 end = (unsigned long)ei + item_size; 632 633 if (found_key.type == BTRFS_EXTENT_ITEM_KEY && 634 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { 635 struct btrfs_tree_block_info *info; 636 637 info = (struct btrfs_tree_block_info *)ptr; 638 *info_level = btrfs_tree_block_level(leaf, info); 639 ptr += sizeof(struct btrfs_tree_block_info); 640 BUG_ON(ptr > end); 641 } else if (found_key.type == BTRFS_METADATA_ITEM_KEY) { 642 *info_level = found_key.offset; 643 } else { 644 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA)); 645 } 646 647 while (ptr < end) { 648 struct btrfs_extent_inline_ref *iref; 649 u64 offset; 650 int type; 651 652 iref = (struct btrfs_extent_inline_ref *)ptr; 653 type = btrfs_extent_inline_ref_type(leaf, iref); 654 offset = btrfs_extent_inline_ref_offset(leaf, iref); 655 656 switch (type) { 657 case BTRFS_SHARED_BLOCK_REF_KEY: 658 ret = __add_prelim_ref(prefs, 0, NULL, 659 *info_level + 1, offset, 660 bytenr, 1); 661 break; 662 case BTRFS_SHARED_DATA_REF_KEY: { 663 struct btrfs_shared_data_ref *sdref; 664 int count; 665 666 sdref = (struct btrfs_shared_data_ref *)(iref + 1); 667 count = btrfs_shared_data_ref_count(leaf, sdref); 668 ret = __add_prelim_ref(prefs, 0, NULL, 0, offset, 669 bytenr, count); 670 break; 671 } 672 case BTRFS_TREE_BLOCK_REF_KEY: 673 ret = __add_prelim_ref(prefs, offset, NULL, 674 *info_level + 1, 0, 675 bytenr, 1); 676 break; 677 case BTRFS_EXTENT_DATA_REF_KEY: { 678 struct btrfs_extent_data_ref *dref; 679 int count; 680 u64 root; 681 682 dref = (struct btrfs_extent_data_ref *)(&iref->offset); 683 count = btrfs_extent_data_ref_count(leaf, dref); 684 key.objectid = btrfs_extent_data_ref_objectid(leaf, 685 dref); 686 key.type = BTRFS_EXTENT_DATA_KEY; 687 key.offset = btrfs_extent_data_ref_offset(leaf, dref); 688 root = btrfs_extent_data_ref_root(leaf, dref); 689 ret = __add_prelim_ref(prefs, root, &key, 0, 0, 690 bytenr, count); 691 break; 692 } 693 default: 694 WARN_ON(1); 695 } 696 if (ret) 697 return ret; 698 ptr += btrfs_extent_inline_ref_size(type); 699 } 700 701 return 0; 702 } 703 704 /* 705 * add all non-inline backrefs for bytenr to the list 706 */ 707 static int __add_keyed_refs(struct btrfs_fs_info *fs_info, 708 struct btrfs_path *path, u64 bytenr, 709 int info_level, struct list_head *prefs) 710 { 711 struct btrfs_root *extent_root = fs_info->extent_root; 712 int ret; 713 int slot; 714 struct extent_buffer *leaf; 715 struct btrfs_key key; 716 717 while (1) { 718 ret = btrfs_next_item(extent_root, path); 719 if (ret < 0) 720 break; 721 if (ret) { 722 ret = 0; 723 break; 724 } 725 726 slot = path->slots[0]; 727 leaf = path->nodes[0]; 728 btrfs_item_key_to_cpu(leaf, &key, slot); 729 730 if (key.objectid != bytenr) 731 break; 732 if (key.type < BTRFS_TREE_BLOCK_REF_KEY) 733 continue; 734 if (key.type > BTRFS_SHARED_DATA_REF_KEY) 735 break; 736 737 switch (key.type) { 738 case BTRFS_SHARED_BLOCK_REF_KEY: 739 ret = __add_prelim_ref(prefs, 0, NULL, 740 info_level + 1, key.offset, 741 bytenr, 1); 742 break; 743 case BTRFS_SHARED_DATA_REF_KEY: { 744 struct btrfs_shared_data_ref *sdref; 745 int count; 746 747 sdref = btrfs_item_ptr(leaf, slot, 748 struct btrfs_shared_data_ref); 749 count = btrfs_shared_data_ref_count(leaf, sdref); 750 ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset, 751 bytenr, count); 752 break; 753 } 754 case BTRFS_TREE_BLOCK_REF_KEY: 755 ret = __add_prelim_ref(prefs, key.offset, NULL, 756 info_level + 1, 0, 757 bytenr, 1); 758 break; 759 case BTRFS_EXTENT_DATA_REF_KEY: { 760 struct btrfs_extent_data_ref *dref; 761 int count; 762 u64 root; 763 764 dref = btrfs_item_ptr(leaf, slot, 765 struct btrfs_extent_data_ref); 766 count = btrfs_extent_data_ref_count(leaf, dref); 767 key.objectid = btrfs_extent_data_ref_objectid(leaf, 768 dref); 769 key.type = BTRFS_EXTENT_DATA_KEY; 770 key.offset = btrfs_extent_data_ref_offset(leaf, dref); 771 root = btrfs_extent_data_ref_root(leaf, dref); 772 ret = __add_prelim_ref(prefs, root, &key, 0, 0, 773 bytenr, count); 774 break; 775 } 776 default: 777 WARN_ON(1); 778 } 779 if (ret) 780 return ret; 781 782 } 783 784 return ret; 785 } 786 787 /* 788 * this adds all existing backrefs (inline backrefs, backrefs and delayed 789 * refs) for the given bytenr to the refs list, merges duplicates and resolves 790 * indirect refs to their parent bytenr. 791 * When roots are found, they're added to the roots list 792 * 793 * FIXME some caching might speed things up 794 */ 795 static int find_parent_nodes(struct btrfs_trans_handle *trans, 796 struct btrfs_fs_info *fs_info, u64 bytenr, 797 u64 time_seq, struct ulist *refs, 798 struct ulist *roots, const u64 *extent_item_pos) 799 { 800 struct btrfs_key key; 801 struct btrfs_path *path; 802 struct btrfs_delayed_ref_root *delayed_refs = NULL; 803 struct btrfs_delayed_ref_head *head; 804 int info_level = 0; 805 int ret; 806 struct list_head prefs_delayed; 807 struct list_head prefs; 808 struct __prelim_ref *ref; 809 810 INIT_LIST_HEAD(&prefs); 811 INIT_LIST_HEAD(&prefs_delayed); 812 813 key.objectid = bytenr; 814 key.offset = (u64)-1; 815 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA)) 816 key.type = BTRFS_METADATA_ITEM_KEY; 817 else 818 key.type = BTRFS_EXTENT_ITEM_KEY; 819 820 path = btrfs_alloc_path(); 821 if (!path) 822 return -ENOMEM; 823 if (!trans) 824 path->search_commit_root = 1; 825 826 /* 827 * grab both a lock on the path and a lock on the delayed ref head. 828 * We need both to get a consistent picture of how the refs look 829 * at a specified point in time 830 */ 831 again: 832 head = NULL; 833 834 ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0); 835 if (ret < 0) 836 goto out; 837 BUG_ON(ret == 0); 838 839 if (trans) { 840 /* 841 * look if there are updates for this ref queued and lock the 842 * head 843 */ 844 delayed_refs = &trans->transaction->delayed_refs; 845 spin_lock(&delayed_refs->lock); 846 head = btrfs_find_delayed_ref_head(trans, bytenr); 847 if (head) { 848 if (!mutex_trylock(&head->mutex)) { 849 atomic_inc(&head->node.refs); 850 spin_unlock(&delayed_refs->lock); 851 852 btrfs_release_path(path); 853 854 /* 855 * Mutex was contended, block until it's 856 * released and try again 857 */ 858 mutex_lock(&head->mutex); 859 mutex_unlock(&head->mutex); 860 btrfs_put_delayed_ref(&head->node); 861 goto again; 862 } 863 ret = __add_delayed_refs(head, time_seq, 864 &prefs_delayed); 865 mutex_unlock(&head->mutex); 866 if (ret) { 867 spin_unlock(&delayed_refs->lock); 868 goto out; 869 } 870 } 871 spin_unlock(&delayed_refs->lock); 872 } 873 874 if (path->slots[0]) { 875 struct extent_buffer *leaf; 876 int slot; 877 878 path->slots[0]--; 879 leaf = path->nodes[0]; 880 slot = path->slots[0]; 881 btrfs_item_key_to_cpu(leaf, &key, slot); 882 if (key.objectid == bytenr && 883 (key.type == BTRFS_EXTENT_ITEM_KEY || 884 key.type == BTRFS_METADATA_ITEM_KEY)) { 885 ret = __add_inline_refs(fs_info, path, bytenr, 886 &info_level, &prefs); 887 if (ret) 888 goto out; 889 ret = __add_keyed_refs(fs_info, path, bytenr, 890 info_level, &prefs); 891 if (ret) 892 goto out; 893 } 894 } 895 btrfs_release_path(path); 896 897 list_splice_init(&prefs_delayed, &prefs); 898 899 ret = __add_missing_keys(fs_info, &prefs); 900 if (ret) 901 goto out; 902 903 __merge_refs(&prefs, 1); 904 905 ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs, 906 extent_item_pos); 907 if (ret) 908 goto out; 909 910 __merge_refs(&prefs, 2); 911 912 while (!list_empty(&prefs)) { 913 ref = list_first_entry(&prefs, struct __prelim_ref, list); 914 list_del(&ref->list); 915 WARN_ON(ref->count < 0); 916 if (ref->count && ref->root_id && ref->parent == 0) { 917 /* no parent == root of tree */ 918 ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS); 919 if (ret < 0) 920 goto out; 921 } 922 if (ref->count && ref->parent) { 923 struct extent_inode_elem *eie = NULL; 924 if (extent_item_pos && !ref->inode_list) { 925 u32 bsz; 926 struct extent_buffer *eb; 927 bsz = btrfs_level_size(fs_info->extent_root, 928 info_level); 929 eb = read_tree_block(fs_info->extent_root, 930 ref->parent, bsz, 0); 931 if (!eb || !extent_buffer_uptodate(eb)) { 932 free_extent_buffer(eb); 933 ret = -EIO; 934 goto out; 935 } 936 ret = find_extent_in_eb(eb, bytenr, 937 *extent_item_pos, &eie); 938 ref->inode_list = eie; 939 free_extent_buffer(eb); 940 } 941 ret = ulist_add_merge(refs, ref->parent, 942 (uintptr_t)ref->inode_list, 943 (u64 *)&eie, GFP_NOFS); 944 if (ret < 0) 945 goto out; 946 if (!ret && extent_item_pos) { 947 /* 948 * we've recorded that parent, so we must extend 949 * its inode list here 950 */ 951 BUG_ON(!eie); 952 while (eie->next) 953 eie = eie->next; 954 eie->next = ref->inode_list; 955 } 956 } 957 kfree(ref); 958 } 959 960 out: 961 btrfs_free_path(path); 962 while (!list_empty(&prefs)) { 963 ref = list_first_entry(&prefs, struct __prelim_ref, list); 964 list_del(&ref->list); 965 kfree(ref); 966 } 967 while (!list_empty(&prefs_delayed)) { 968 ref = list_first_entry(&prefs_delayed, struct __prelim_ref, 969 list); 970 list_del(&ref->list); 971 kfree(ref); 972 } 973 974 return ret; 975 } 976 977 static void free_leaf_list(struct ulist *blocks) 978 { 979 struct ulist_node *node = NULL; 980 struct extent_inode_elem *eie; 981 struct extent_inode_elem *eie_next; 982 struct ulist_iterator uiter; 983 984 ULIST_ITER_INIT(&uiter); 985 while ((node = ulist_next(blocks, &uiter))) { 986 if (!node->aux) 987 continue; 988 eie = (struct extent_inode_elem *)(uintptr_t)node->aux; 989 for (; eie; eie = eie_next) { 990 eie_next = eie->next; 991 kfree(eie); 992 } 993 node->aux = 0; 994 } 995 996 ulist_free(blocks); 997 } 998 999 /* 1000 * Finds all leafs with a reference to the specified combination of bytenr and 1001 * offset. key_list_head will point to a list of corresponding keys (caller must 1002 * free each list element). The leafs will be stored in the leafs ulist, which 1003 * must be freed with ulist_free. 1004 * 1005 * returns 0 on success, <0 on error 1006 */ 1007 static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, 1008 struct btrfs_fs_info *fs_info, u64 bytenr, 1009 u64 time_seq, struct ulist **leafs, 1010 const u64 *extent_item_pos) 1011 { 1012 struct ulist *tmp; 1013 int ret; 1014 1015 tmp = ulist_alloc(GFP_NOFS); 1016 if (!tmp) 1017 return -ENOMEM; 1018 *leafs = ulist_alloc(GFP_NOFS); 1019 if (!*leafs) { 1020 ulist_free(tmp); 1021 return -ENOMEM; 1022 } 1023 1024 ret = find_parent_nodes(trans, fs_info, bytenr, 1025 time_seq, *leafs, tmp, extent_item_pos); 1026 ulist_free(tmp); 1027 1028 if (ret < 0 && ret != -ENOENT) { 1029 free_leaf_list(*leafs); 1030 return ret; 1031 } 1032 1033 return 0; 1034 } 1035 1036 /* 1037 * walk all backrefs for a given extent to find all roots that reference this 1038 * extent. Walking a backref means finding all extents that reference this 1039 * extent and in turn walk the backrefs of those, too. Naturally this is a 1040 * recursive process, but here it is implemented in an iterative fashion: We 1041 * find all referencing extents for the extent in question and put them on a 1042 * list. In turn, we find all referencing extents for those, further appending 1043 * to the list. The way we iterate the list allows adding more elements after 1044 * the current while iterating. The process stops when we reach the end of the 1045 * list. Found roots are added to the roots list. 1046 * 1047 * returns 0 on success, < 0 on error. 1048 */ 1049 int btrfs_find_all_roots(struct btrfs_trans_handle *trans, 1050 struct btrfs_fs_info *fs_info, u64 bytenr, 1051 u64 time_seq, struct ulist **roots) 1052 { 1053 struct ulist *tmp; 1054 struct ulist_node *node = NULL; 1055 struct ulist_iterator uiter; 1056 int ret; 1057 1058 tmp = ulist_alloc(GFP_NOFS); 1059 if (!tmp) 1060 return -ENOMEM; 1061 *roots = ulist_alloc(GFP_NOFS); 1062 if (!*roots) { 1063 ulist_free(tmp); 1064 return -ENOMEM; 1065 } 1066 1067 ULIST_ITER_INIT(&uiter); 1068 while (1) { 1069 ret = find_parent_nodes(trans, fs_info, bytenr, 1070 time_seq, tmp, *roots, NULL); 1071 if (ret < 0 && ret != -ENOENT) { 1072 ulist_free(tmp); 1073 ulist_free(*roots); 1074 return ret; 1075 } 1076 node = ulist_next(tmp, &uiter); 1077 if (!node) 1078 break; 1079 bytenr = node->val; 1080 } 1081 1082 ulist_free(tmp); 1083 return 0; 1084 } 1085 1086 1087 static int __inode_info(u64 inum, u64 ioff, u8 key_type, 1088 struct btrfs_root *fs_root, struct btrfs_path *path, 1089 struct btrfs_key *found_key) 1090 { 1091 int ret; 1092 struct btrfs_key key; 1093 struct extent_buffer *eb; 1094 1095 key.type = key_type; 1096 key.objectid = inum; 1097 key.offset = ioff; 1098 1099 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0); 1100 if (ret < 0) 1101 return ret; 1102 1103 eb = path->nodes[0]; 1104 if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { 1105 ret = btrfs_next_leaf(fs_root, path); 1106 if (ret) 1107 return ret; 1108 eb = path->nodes[0]; 1109 } 1110 1111 btrfs_item_key_to_cpu(eb, found_key, path->slots[0]); 1112 if (found_key->type != key.type || found_key->objectid != key.objectid) 1113 return 1; 1114 1115 return 0; 1116 } 1117 1118 /* 1119 * this makes the path point to (inum INODE_ITEM ioff) 1120 */ 1121 int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, 1122 struct btrfs_path *path) 1123 { 1124 struct btrfs_key key; 1125 return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path, 1126 &key); 1127 } 1128 1129 static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, 1130 struct btrfs_path *path, 1131 struct btrfs_key *found_key) 1132 { 1133 return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path, 1134 found_key); 1135 } 1136 1137 int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid, 1138 u64 start_off, struct btrfs_path *path, 1139 struct btrfs_inode_extref **ret_extref, 1140 u64 *found_off) 1141 { 1142 int ret, slot; 1143 struct btrfs_key key; 1144 struct btrfs_key found_key; 1145 struct btrfs_inode_extref *extref; 1146 struct extent_buffer *leaf; 1147 unsigned long ptr; 1148 1149 key.objectid = inode_objectid; 1150 btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY); 1151 key.offset = start_off; 1152 1153 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 1154 if (ret < 0) 1155 return ret; 1156 1157 while (1) { 1158 leaf = path->nodes[0]; 1159 slot = path->slots[0]; 1160 if (slot >= btrfs_header_nritems(leaf)) { 1161 /* 1162 * If the item at offset is not found, 1163 * btrfs_search_slot will point us to the slot 1164 * where it should be inserted. In our case 1165 * that will be the slot directly before the 1166 * next INODE_REF_KEY_V2 item. In the case 1167 * that we're pointing to the last slot in a 1168 * leaf, we must move one leaf over. 1169 */ 1170 ret = btrfs_next_leaf(root, path); 1171 if (ret) { 1172 if (ret >= 1) 1173 ret = -ENOENT; 1174 break; 1175 } 1176 continue; 1177 } 1178 1179 btrfs_item_key_to_cpu(leaf, &found_key, slot); 1180 1181 /* 1182 * Check that we're still looking at an extended ref key for 1183 * this particular objectid. If we have different 1184 * objectid or type then there are no more to be found 1185 * in the tree and we can exit. 1186 */ 1187 ret = -ENOENT; 1188 if (found_key.objectid != inode_objectid) 1189 break; 1190 if (btrfs_key_type(&found_key) != BTRFS_INODE_EXTREF_KEY) 1191 break; 1192 1193 ret = 0; 1194 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); 1195 extref = (struct btrfs_inode_extref *)ptr; 1196 *ret_extref = extref; 1197 if (found_off) 1198 *found_off = found_key.offset; 1199 break; 1200 } 1201 1202 return ret; 1203 } 1204 1205 /* 1206 * this iterates to turn a name (from iref/extref) into a full filesystem path. 1207 * Elements of the path are separated by '/' and the path is guaranteed to be 1208 * 0-terminated. the path is only given within the current file system. 1209 * Therefore, it never starts with a '/'. the caller is responsible to provide 1210 * "size" bytes in "dest". the dest buffer will be filled backwards. finally, 1211 * the start point of the resulting string is returned. this pointer is within 1212 * dest, normally. 1213 * in case the path buffer would overflow, the pointer is decremented further 1214 * as if output was written to the buffer, though no more output is actually 1215 * generated. that way, the caller can determine how much space would be 1216 * required for the path to fit into the buffer. in that case, the returned 1217 * value will be smaller than dest. callers must check this! 1218 */ 1219 char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path, 1220 u32 name_len, unsigned long name_off, 1221 struct extent_buffer *eb_in, u64 parent, 1222 char *dest, u32 size) 1223 { 1224 int slot; 1225 u64 next_inum; 1226 int ret; 1227 s64 bytes_left = ((s64)size) - 1; 1228 struct extent_buffer *eb = eb_in; 1229 struct btrfs_key found_key; 1230 int leave_spinning = path->leave_spinning; 1231 struct btrfs_inode_ref *iref; 1232 1233 if (bytes_left >= 0) 1234 dest[bytes_left] = '\0'; 1235 1236 path->leave_spinning = 1; 1237 while (1) { 1238 bytes_left -= name_len; 1239 if (bytes_left >= 0) 1240 read_extent_buffer(eb, dest + bytes_left, 1241 name_off, name_len); 1242 if (eb != eb_in) { 1243 btrfs_tree_read_unlock_blocking(eb); 1244 free_extent_buffer(eb); 1245 } 1246 ret = inode_ref_info(parent, 0, fs_root, path, &found_key); 1247 if (ret > 0) 1248 ret = -ENOENT; 1249 if (ret) 1250 break; 1251 1252 next_inum = found_key.offset; 1253 1254 /* regular exit ahead */ 1255 if (parent == next_inum) 1256 break; 1257 1258 slot = path->slots[0]; 1259 eb = path->nodes[0]; 1260 /* make sure we can use eb after releasing the path */ 1261 if (eb != eb_in) { 1262 atomic_inc(&eb->refs); 1263 btrfs_tree_read_lock(eb); 1264 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); 1265 } 1266 btrfs_release_path(path); 1267 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); 1268 1269 name_len = btrfs_inode_ref_name_len(eb, iref); 1270 name_off = (unsigned long)(iref + 1); 1271 1272 parent = next_inum; 1273 --bytes_left; 1274 if (bytes_left >= 0) 1275 dest[bytes_left] = '/'; 1276 } 1277 1278 btrfs_release_path(path); 1279 path->leave_spinning = leave_spinning; 1280 1281 if (ret) 1282 return ERR_PTR(ret); 1283 1284 return dest + bytes_left; 1285 } 1286 1287 /* 1288 * this makes the path point to (logical EXTENT_ITEM *) 1289 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for 1290 * tree blocks and <0 on error. 1291 */ 1292 int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, 1293 struct btrfs_path *path, struct btrfs_key *found_key, 1294 u64 *flags_ret) 1295 { 1296 int ret; 1297 u64 flags; 1298 u64 size = 0; 1299 u32 item_size; 1300 struct extent_buffer *eb; 1301 struct btrfs_extent_item *ei; 1302 struct btrfs_key key; 1303 1304 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA)) 1305 key.type = BTRFS_METADATA_ITEM_KEY; 1306 else 1307 key.type = BTRFS_EXTENT_ITEM_KEY; 1308 key.objectid = logical; 1309 key.offset = (u64)-1; 1310 1311 ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); 1312 if (ret < 0) 1313 return ret; 1314 ret = btrfs_previous_item(fs_info->extent_root, path, 1315 0, BTRFS_EXTENT_ITEM_KEY); 1316 if (ret < 0) 1317 return ret; 1318 1319 btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]); 1320 if (found_key->type == BTRFS_METADATA_ITEM_KEY) 1321 size = fs_info->extent_root->leafsize; 1322 else if (found_key->type == BTRFS_EXTENT_ITEM_KEY) 1323 size = found_key->offset; 1324 1325 if ((found_key->type != BTRFS_EXTENT_ITEM_KEY && 1326 found_key->type != BTRFS_METADATA_ITEM_KEY) || 1327 found_key->objectid > logical || 1328 found_key->objectid + size <= logical) { 1329 pr_debug("logical %llu is not within any extent\n", 1330 (unsigned long long)logical); 1331 return -ENOENT; 1332 } 1333 1334 eb = path->nodes[0]; 1335 item_size = btrfs_item_size_nr(eb, path->slots[0]); 1336 BUG_ON(item_size < sizeof(*ei)); 1337 1338 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); 1339 flags = btrfs_extent_flags(eb, ei); 1340 1341 pr_debug("logical %llu is at position %llu within the extent (%llu " 1342 "EXTENT_ITEM %llu) flags %#llx size %u\n", 1343 (unsigned long long)logical, 1344 (unsigned long long)(logical - found_key->objectid), 1345 (unsigned long long)found_key->objectid, 1346 (unsigned long long)found_key->offset, 1347 (unsigned long long)flags, item_size); 1348 1349 WARN_ON(!flags_ret); 1350 if (flags_ret) { 1351 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) 1352 *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK; 1353 else if (flags & BTRFS_EXTENT_FLAG_DATA) 1354 *flags_ret = BTRFS_EXTENT_FLAG_DATA; 1355 else 1356 BUG_ON(1); 1357 return 0; 1358 } 1359 1360 return -EIO; 1361 } 1362 1363 /* 1364 * helper function to iterate extent inline refs. ptr must point to a 0 value 1365 * for the first call and may be modified. it is used to track state. 1366 * if more refs exist, 0 is returned and the next call to 1367 * __get_extent_inline_ref must pass the modified ptr parameter to get the 1368 * next ref. after the last ref was processed, 1 is returned. 1369 * returns <0 on error 1370 */ 1371 static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb, 1372 struct btrfs_extent_item *ei, u32 item_size, 1373 struct btrfs_extent_inline_ref **out_eiref, 1374 int *out_type) 1375 { 1376 unsigned long end; 1377 u64 flags; 1378 struct btrfs_tree_block_info *info; 1379 1380 if (!*ptr) { 1381 /* first call */ 1382 flags = btrfs_extent_flags(eb, ei); 1383 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { 1384 info = (struct btrfs_tree_block_info *)(ei + 1); 1385 *out_eiref = 1386 (struct btrfs_extent_inline_ref *)(info + 1); 1387 } else { 1388 *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1); 1389 } 1390 *ptr = (unsigned long)*out_eiref; 1391 if ((void *)*ptr >= (void *)ei + item_size) 1392 return -ENOENT; 1393 } 1394 1395 end = (unsigned long)ei + item_size; 1396 *out_eiref = (struct btrfs_extent_inline_ref *)*ptr; 1397 *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref); 1398 1399 *ptr += btrfs_extent_inline_ref_size(*out_type); 1400 WARN_ON(*ptr > end); 1401 if (*ptr == end) 1402 return 1; /* last */ 1403 1404 return 0; 1405 } 1406 1407 /* 1408 * reads the tree block backref for an extent. tree level and root are returned 1409 * through out_level and out_root. ptr must point to a 0 value for the first 1410 * call and may be modified (see __get_extent_inline_ref comment). 1411 * returns 0 if data was provided, 1 if there was no more data to provide or 1412 * <0 on error. 1413 */ 1414 int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb, 1415 struct btrfs_extent_item *ei, u32 item_size, 1416 u64 *out_root, u8 *out_level) 1417 { 1418 int ret; 1419 int type; 1420 struct btrfs_tree_block_info *info; 1421 struct btrfs_extent_inline_ref *eiref; 1422 1423 if (*ptr == (unsigned long)-1) 1424 return 1; 1425 1426 while (1) { 1427 ret = __get_extent_inline_ref(ptr, eb, ei, item_size, 1428 &eiref, &type); 1429 if (ret < 0) 1430 return ret; 1431 1432 if (type == BTRFS_TREE_BLOCK_REF_KEY || 1433 type == BTRFS_SHARED_BLOCK_REF_KEY) 1434 break; 1435 1436 if (ret == 1) 1437 return 1; 1438 } 1439 1440 /* we can treat both ref types equally here */ 1441 info = (struct btrfs_tree_block_info *)(ei + 1); 1442 *out_root = btrfs_extent_inline_ref_offset(eb, eiref); 1443 *out_level = btrfs_tree_block_level(eb, info); 1444 1445 if (ret == 1) 1446 *ptr = (unsigned long)-1; 1447 1448 return 0; 1449 } 1450 1451 static int iterate_leaf_refs(struct extent_inode_elem *inode_list, 1452 u64 root, u64 extent_item_objectid, 1453 iterate_extent_inodes_t *iterate, void *ctx) 1454 { 1455 struct extent_inode_elem *eie; 1456 int ret = 0; 1457 1458 for (eie = inode_list; eie; eie = eie->next) { 1459 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), " 1460 "root %llu\n", extent_item_objectid, 1461 eie->inum, eie->offset, root); 1462 ret = iterate(eie->inum, eie->offset, root, ctx); 1463 if (ret) { 1464 pr_debug("stopping iteration for %llu due to ret=%d\n", 1465 extent_item_objectid, ret); 1466 break; 1467 } 1468 } 1469 1470 return ret; 1471 } 1472 1473 /* 1474 * calls iterate() for every inode that references the extent identified by 1475 * the given parameters. 1476 * when the iterator function returns a non-zero value, iteration stops. 1477 */ 1478 int iterate_extent_inodes(struct btrfs_fs_info *fs_info, 1479 u64 extent_item_objectid, u64 extent_item_pos, 1480 int search_commit_root, 1481 iterate_extent_inodes_t *iterate, void *ctx) 1482 { 1483 int ret; 1484 struct btrfs_trans_handle *trans = NULL; 1485 struct ulist *refs = NULL; 1486 struct ulist *roots = NULL; 1487 struct ulist_node *ref_node = NULL; 1488 struct ulist_node *root_node = NULL; 1489 struct seq_list tree_mod_seq_elem = {}; 1490 struct ulist_iterator ref_uiter; 1491 struct ulist_iterator root_uiter; 1492 1493 pr_debug("resolving all inodes for extent %llu\n", 1494 extent_item_objectid); 1495 1496 if (!search_commit_root) { 1497 trans = btrfs_join_transaction(fs_info->extent_root); 1498 if (IS_ERR(trans)) 1499 return PTR_ERR(trans); 1500 btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem); 1501 } 1502 1503 ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid, 1504 tree_mod_seq_elem.seq, &refs, 1505 &extent_item_pos); 1506 if (ret) 1507 goto out; 1508 1509 ULIST_ITER_INIT(&ref_uiter); 1510 while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) { 1511 ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, 1512 tree_mod_seq_elem.seq, &roots); 1513 if (ret) 1514 break; 1515 ULIST_ITER_INIT(&root_uiter); 1516 while (!ret && (root_node = ulist_next(roots, &root_uiter))) { 1517 pr_debug("root %llu references leaf %llu, data list " 1518 "%#llx\n", root_node->val, ref_node->val, 1519 (long long)ref_node->aux); 1520 ret = iterate_leaf_refs((struct extent_inode_elem *) 1521 (uintptr_t)ref_node->aux, 1522 root_node->val, 1523 extent_item_objectid, 1524 iterate, ctx); 1525 } 1526 ulist_free(roots); 1527 } 1528 1529 free_leaf_list(refs); 1530 out: 1531 if (!search_commit_root) { 1532 btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem); 1533 btrfs_end_transaction(trans, fs_info->extent_root); 1534 } 1535 1536 return ret; 1537 } 1538 1539 int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info, 1540 struct btrfs_path *path, 1541 iterate_extent_inodes_t *iterate, void *ctx) 1542 { 1543 int ret; 1544 u64 extent_item_pos; 1545 u64 flags = 0; 1546 struct btrfs_key found_key; 1547 int search_commit_root = path->search_commit_root; 1548 1549 ret = extent_from_logical(fs_info, logical, path, &found_key, &flags); 1550 btrfs_release_path(path); 1551 if (ret < 0) 1552 return ret; 1553 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) 1554 return -EINVAL; 1555 1556 extent_item_pos = logical - found_key.objectid; 1557 ret = iterate_extent_inodes(fs_info, found_key.objectid, 1558 extent_item_pos, search_commit_root, 1559 iterate, ctx); 1560 1561 return ret; 1562 } 1563 1564 typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off, 1565 struct extent_buffer *eb, void *ctx); 1566 1567 static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root, 1568 struct btrfs_path *path, 1569 iterate_irefs_t *iterate, void *ctx) 1570 { 1571 int ret = 0; 1572 int slot; 1573 u32 cur; 1574 u32 len; 1575 u32 name_len; 1576 u64 parent = 0; 1577 int found = 0; 1578 struct extent_buffer *eb; 1579 struct btrfs_item *item; 1580 struct btrfs_inode_ref *iref; 1581 struct btrfs_key found_key; 1582 1583 while (!ret) { 1584 path->leave_spinning = 1; 1585 ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path, 1586 &found_key); 1587 if (ret < 0) 1588 break; 1589 if (ret) { 1590 ret = found ? 0 : -ENOENT; 1591 break; 1592 } 1593 ++found; 1594 1595 parent = found_key.offset; 1596 slot = path->slots[0]; 1597 eb = path->nodes[0]; 1598 /* make sure we can use eb after releasing the path */ 1599 atomic_inc(&eb->refs); 1600 btrfs_tree_read_lock(eb); 1601 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); 1602 btrfs_release_path(path); 1603 1604 item = btrfs_item_nr(eb, slot); 1605 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); 1606 1607 for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) { 1608 name_len = btrfs_inode_ref_name_len(eb, iref); 1609 /* path must be released before calling iterate()! */ 1610 pr_debug("following ref at offset %u for inode %llu in " 1611 "tree %llu\n", cur, 1612 (unsigned long long)found_key.objectid, 1613 (unsigned long long)fs_root->objectid); 1614 ret = iterate(parent, name_len, 1615 (unsigned long)(iref + 1), eb, ctx); 1616 if (ret) 1617 break; 1618 len = sizeof(*iref) + name_len; 1619 iref = (struct btrfs_inode_ref *)((char *)iref + len); 1620 } 1621 btrfs_tree_read_unlock_blocking(eb); 1622 free_extent_buffer(eb); 1623 } 1624 1625 btrfs_release_path(path); 1626 1627 return ret; 1628 } 1629 1630 static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, 1631 struct btrfs_path *path, 1632 iterate_irefs_t *iterate, void *ctx) 1633 { 1634 int ret; 1635 int slot; 1636 u64 offset = 0; 1637 u64 parent; 1638 int found = 0; 1639 struct extent_buffer *eb; 1640 struct btrfs_inode_extref *extref; 1641 struct extent_buffer *leaf; 1642 u32 item_size; 1643 u32 cur_offset; 1644 unsigned long ptr; 1645 1646 while (1) { 1647 ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref, 1648 &offset); 1649 if (ret < 0) 1650 break; 1651 if (ret) { 1652 ret = found ? 0 : -ENOENT; 1653 break; 1654 } 1655 ++found; 1656 1657 slot = path->slots[0]; 1658 eb = path->nodes[0]; 1659 /* make sure we can use eb after releasing the path */ 1660 atomic_inc(&eb->refs); 1661 1662 btrfs_tree_read_lock(eb); 1663 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); 1664 btrfs_release_path(path); 1665 1666 leaf = path->nodes[0]; 1667 item_size = btrfs_item_size_nr(leaf, path->slots[0]); 1668 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); 1669 cur_offset = 0; 1670 1671 while (cur_offset < item_size) { 1672 u32 name_len; 1673 1674 extref = (struct btrfs_inode_extref *)(ptr + cur_offset); 1675 parent = btrfs_inode_extref_parent(eb, extref); 1676 name_len = btrfs_inode_extref_name_len(eb, extref); 1677 ret = iterate(parent, name_len, 1678 (unsigned long)&extref->name, eb, ctx); 1679 if (ret) 1680 break; 1681 1682 cur_offset += btrfs_inode_extref_name_len(leaf, extref); 1683 cur_offset += sizeof(*extref); 1684 } 1685 btrfs_tree_read_unlock_blocking(eb); 1686 free_extent_buffer(eb); 1687 1688 offset++; 1689 } 1690 1691 btrfs_release_path(path); 1692 1693 return ret; 1694 } 1695 1696 static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, 1697 struct btrfs_path *path, iterate_irefs_t *iterate, 1698 void *ctx) 1699 { 1700 int ret; 1701 int found_refs = 0; 1702 1703 ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx); 1704 if (!ret) 1705 ++found_refs; 1706 else if (ret != -ENOENT) 1707 return ret; 1708 1709 ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx); 1710 if (ret == -ENOENT && found_refs) 1711 return 0; 1712 1713 return ret; 1714 } 1715 1716 /* 1717 * returns 0 if the path could be dumped (probably truncated) 1718 * returns <0 in case of an error 1719 */ 1720 static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off, 1721 struct extent_buffer *eb, void *ctx) 1722 { 1723 struct inode_fs_paths *ipath = ctx; 1724 char *fspath; 1725 char *fspath_min; 1726 int i = ipath->fspath->elem_cnt; 1727 const int s_ptr = sizeof(char *); 1728 u32 bytes_left; 1729 1730 bytes_left = ipath->fspath->bytes_left > s_ptr ? 1731 ipath->fspath->bytes_left - s_ptr : 0; 1732 1733 fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr; 1734 fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len, 1735 name_off, eb, inum, fspath_min, bytes_left); 1736 if (IS_ERR(fspath)) 1737 return PTR_ERR(fspath); 1738 1739 if (fspath > fspath_min) { 1740 ipath->fspath->val[i] = (u64)(unsigned long)fspath; 1741 ++ipath->fspath->elem_cnt; 1742 ipath->fspath->bytes_left = fspath - fspath_min; 1743 } else { 1744 ++ipath->fspath->elem_missed; 1745 ipath->fspath->bytes_missing += fspath_min - fspath; 1746 ipath->fspath->bytes_left = 0; 1747 } 1748 1749 return 0; 1750 } 1751 1752 /* 1753 * this dumps all file system paths to the inode into the ipath struct, provided 1754 * is has been created large enough. each path is zero-terminated and accessed 1755 * from ipath->fspath->val[i]. 1756 * when it returns, there are ipath->fspath->elem_cnt number of paths available 1757 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the 1758 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise, 1759 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would 1760 * have been needed to return all paths. 1761 */ 1762 int paths_from_inode(u64 inum, struct inode_fs_paths *ipath) 1763 { 1764 return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path, 1765 inode_to_path, ipath); 1766 } 1767 1768 struct btrfs_data_container *init_data_container(u32 total_bytes) 1769 { 1770 struct btrfs_data_container *data; 1771 size_t alloc_bytes; 1772 1773 alloc_bytes = max_t(size_t, total_bytes, sizeof(*data)); 1774 data = vmalloc(alloc_bytes); 1775 if (!data) 1776 return ERR_PTR(-ENOMEM); 1777 1778 if (total_bytes >= sizeof(*data)) { 1779 data->bytes_left = total_bytes - sizeof(*data); 1780 data->bytes_missing = 0; 1781 } else { 1782 data->bytes_missing = sizeof(*data) - total_bytes; 1783 data->bytes_left = 0; 1784 } 1785 1786 data->elem_cnt = 0; 1787 data->elem_missed = 0; 1788 1789 return data; 1790 } 1791 1792 /* 1793 * allocates space to return multiple file system paths for an inode. 1794 * total_bytes to allocate are passed, note that space usable for actual path 1795 * information will be total_bytes - sizeof(struct inode_fs_paths). 1796 * the returned pointer must be freed with free_ipath() in the end. 1797 */ 1798 struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root, 1799 struct btrfs_path *path) 1800 { 1801 struct inode_fs_paths *ifp; 1802 struct btrfs_data_container *fspath; 1803 1804 fspath = init_data_container(total_bytes); 1805 if (IS_ERR(fspath)) 1806 return (void *)fspath; 1807 1808 ifp = kmalloc(sizeof(*ifp), GFP_NOFS); 1809 if (!ifp) { 1810 kfree(fspath); 1811 return ERR_PTR(-ENOMEM); 1812 } 1813 1814 ifp->btrfs_path = path; 1815 ifp->fspath = fspath; 1816 ifp->fs_root = fs_root; 1817 1818 return ifp; 1819 } 1820 1821 void free_ipath(struct inode_fs_paths *ipath) 1822 { 1823 if (!ipath) 1824 return; 1825 vfree(ipath->fspath); 1826 kfree(ipath); 1827 } 1828