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 "ctree.h" 20 #include "disk-io.h" 21 #include "backref.h" 22 #include "ulist.h" 23 #include "transaction.h" 24 #include "delayed-ref.h" 25 26 /* 27 * this structure records all encountered refs on the way up to the root 28 */ 29 struct __prelim_ref { 30 struct list_head list; 31 u64 root_id; 32 struct btrfs_key key; 33 int level; 34 int count; 35 u64 parent; 36 u64 wanted_disk_byte; 37 }; 38 39 static int __add_prelim_ref(struct list_head *head, u64 root_id, 40 struct btrfs_key *key, int level, u64 parent, 41 u64 wanted_disk_byte, int count) 42 { 43 struct __prelim_ref *ref; 44 45 /* in case we're adding delayed refs, we're holding the refs spinlock */ 46 ref = kmalloc(sizeof(*ref), GFP_ATOMIC); 47 if (!ref) 48 return -ENOMEM; 49 50 ref->root_id = root_id; 51 if (key) 52 ref->key = *key; 53 else 54 memset(&ref->key, 0, sizeof(ref->key)); 55 56 ref->level = level; 57 ref->count = count; 58 ref->parent = parent; 59 ref->wanted_disk_byte = wanted_disk_byte; 60 list_add_tail(&ref->list, head); 61 62 return 0; 63 } 64 65 static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, 66 struct ulist *parents, 67 struct extent_buffer *eb, int level, 68 u64 wanted_objectid, u64 wanted_disk_byte) 69 { 70 int ret; 71 int slot; 72 struct btrfs_file_extent_item *fi; 73 struct btrfs_key key; 74 u64 disk_byte; 75 76 add_parent: 77 ret = ulist_add(parents, eb->start, 0, GFP_NOFS); 78 if (ret < 0) 79 return ret; 80 81 if (level != 0) 82 return 0; 83 84 /* 85 * if the current leaf is full with EXTENT_DATA items, we must 86 * check the next one if that holds a reference as well. 87 * ref->count cannot be used to skip this check. 88 * repeat this until we don't find any additional EXTENT_DATA items. 89 */ 90 while (1) { 91 ret = btrfs_next_leaf(root, path); 92 if (ret < 0) 93 return ret; 94 if (ret) 95 return 0; 96 97 eb = path->nodes[0]; 98 for (slot = 0; slot < btrfs_header_nritems(eb); ++slot) { 99 btrfs_item_key_to_cpu(eb, &key, slot); 100 if (key.objectid != wanted_objectid || 101 key.type != BTRFS_EXTENT_DATA_KEY) 102 return 0; 103 fi = btrfs_item_ptr(eb, slot, 104 struct btrfs_file_extent_item); 105 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); 106 if (disk_byte == wanted_disk_byte) 107 goto add_parent; 108 } 109 } 110 111 return 0; 112 } 113 114 /* 115 * resolve an indirect backref in the form (root_id, key, level) 116 * to a logical address 117 */ 118 static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, 119 struct __prelim_ref *ref, 120 struct ulist *parents) 121 { 122 struct btrfs_path *path; 123 struct btrfs_root *root; 124 struct btrfs_key root_key; 125 struct btrfs_key key = {0}; 126 struct extent_buffer *eb; 127 int ret = 0; 128 int root_level; 129 int level = ref->level; 130 131 path = btrfs_alloc_path(); 132 if (!path) 133 return -ENOMEM; 134 135 root_key.objectid = ref->root_id; 136 root_key.type = BTRFS_ROOT_ITEM_KEY; 137 root_key.offset = (u64)-1; 138 root = btrfs_read_fs_root_no_name(fs_info, &root_key); 139 if (IS_ERR(root)) { 140 ret = PTR_ERR(root); 141 goto out; 142 } 143 144 rcu_read_lock(); 145 root_level = btrfs_header_level(root->node); 146 rcu_read_unlock(); 147 148 if (root_level + 1 == level) 149 goto out; 150 151 path->lowest_level = level; 152 ret = btrfs_search_slot(NULL, root, &ref->key, path, 0, 0); 153 pr_debug("search slot in root %llu (level %d, ref count %d) returned " 154 "%d for key (%llu %u %llu)\n", 155 (unsigned long long)ref->root_id, level, ref->count, ret, 156 (unsigned long long)ref->key.objectid, ref->key.type, 157 (unsigned long long)ref->key.offset); 158 if (ret < 0) 159 goto out; 160 161 eb = path->nodes[level]; 162 if (!eb) { 163 WARN_ON(1); 164 ret = 1; 165 goto out; 166 } 167 168 if (level == 0) { 169 if (ret == 1 && path->slots[0] >= btrfs_header_nritems(eb)) { 170 ret = btrfs_next_leaf(root, path); 171 if (ret) 172 goto out; 173 eb = path->nodes[0]; 174 } 175 176 btrfs_item_key_to_cpu(eb, &key, path->slots[0]); 177 } 178 179 /* the last two parameters will only be used for level == 0 */ 180 ret = add_all_parents(root, path, parents, eb, level, key.objectid, 181 ref->wanted_disk_byte); 182 out: 183 btrfs_free_path(path); 184 return ret; 185 } 186 187 /* 188 * resolve all indirect backrefs from the list 189 */ 190 static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info, 191 struct list_head *head) 192 { 193 int err; 194 int ret = 0; 195 struct __prelim_ref *ref; 196 struct __prelim_ref *ref_safe; 197 struct __prelim_ref *new_ref; 198 struct ulist *parents; 199 struct ulist_node *node; 200 201 parents = ulist_alloc(GFP_NOFS); 202 if (!parents) 203 return -ENOMEM; 204 205 /* 206 * _safe allows us to insert directly after the current item without 207 * iterating over the newly inserted items. 208 * we're also allowed to re-assign ref during iteration. 209 */ 210 list_for_each_entry_safe(ref, ref_safe, head, list) { 211 if (ref->parent) /* already direct */ 212 continue; 213 if (ref->count == 0) 214 continue; 215 err = __resolve_indirect_ref(fs_info, ref, parents); 216 if (err) { 217 if (ret == 0) 218 ret = err; 219 continue; 220 } 221 222 /* we put the first parent into the ref at hand */ 223 node = ulist_next(parents, NULL); 224 ref->parent = node ? node->val : 0; 225 226 /* additional parents require new refs being added here */ 227 while ((node = ulist_next(parents, node))) { 228 new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS); 229 if (!new_ref) { 230 ret = -ENOMEM; 231 break; 232 } 233 memcpy(new_ref, ref, sizeof(*ref)); 234 new_ref->parent = node->val; 235 list_add(&new_ref->list, &ref->list); 236 } 237 ulist_reinit(parents); 238 } 239 240 ulist_free(parents); 241 return ret; 242 } 243 244 /* 245 * merge two lists of backrefs and adjust counts accordingly 246 * 247 * mode = 1: merge identical keys, if key is set 248 * mode = 2: merge identical parents 249 */ 250 static int __merge_refs(struct list_head *head, int mode) 251 { 252 struct list_head *pos1; 253 254 list_for_each(pos1, head) { 255 struct list_head *n2; 256 struct list_head *pos2; 257 struct __prelim_ref *ref1; 258 259 ref1 = list_entry(pos1, struct __prelim_ref, list); 260 261 if (mode == 1 && ref1->key.type == 0) 262 continue; 263 for (pos2 = pos1->next, n2 = pos2->next; pos2 != head; 264 pos2 = n2, n2 = pos2->next) { 265 struct __prelim_ref *ref2; 266 267 ref2 = list_entry(pos2, struct __prelim_ref, list); 268 269 if (mode == 1) { 270 if (memcmp(&ref1->key, &ref2->key, 271 sizeof(ref1->key)) || 272 ref1->level != ref2->level || 273 ref1->root_id != ref2->root_id) 274 continue; 275 ref1->count += ref2->count; 276 } else { 277 if (ref1->parent != ref2->parent) 278 continue; 279 ref1->count += ref2->count; 280 } 281 list_del(&ref2->list); 282 kfree(ref2); 283 } 284 285 } 286 return 0; 287 } 288 289 /* 290 * add all currently queued delayed refs from this head whose seq nr is 291 * smaller or equal that seq to the list 292 */ 293 static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq, 294 struct btrfs_key *info_key, 295 struct list_head *prefs) 296 { 297 struct btrfs_delayed_extent_op *extent_op = head->extent_op; 298 struct rb_node *n = &head->node.rb_node; 299 int sgn; 300 int ret = 0; 301 302 if (extent_op && extent_op->update_key) 303 btrfs_disk_key_to_cpu(info_key, &extent_op->key); 304 305 while ((n = rb_prev(n))) { 306 struct btrfs_delayed_ref_node *node; 307 node = rb_entry(n, struct btrfs_delayed_ref_node, 308 rb_node); 309 if (node->bytenr != head->node.bytenr) 310 break; 311 WARN_ON(node->is_head); 312 313 if (node->seq > seq) 314 continue; 315 316 switch (node->action) { 317 case BTRFS_ADD_DELAYED_EXTENT: 318 case BTRFS_UPDATE_DELAYED_HEAD: 319 WARN_ON(1); 320 continue; 321 case BTRFS_ADD_DELAYED_REF: 322 sgn = 1; 323 break; 324 case BTRFS_DROP_DELAYED_REF: 325 sgn = -1; 326 break; 327 default: 328 BUG_ON(1); 329 } 330 switch (node->type) { 331 case BTRFS_TREE_BLOCK_REF_KEY: { 332 struct btrfs_delayed_tree_ref *ref; 333 334 ref = btrfs_delayed_node_to_tree_ref(node); 335 ret = __add_prelim_ref(prefs, ref->root, info_key, 336 ref->level + 1, 0, node->bytenr, 337 node->ref_mod * sgn); 338 break; 339 } 340 case BTRFS_SHARED_BLOCK_REF_KEY: { 341 struct btrfs_delayed_tree_ref *ref; 342 343 ref = btrfs_delayed_node_to_tree_ref(node); 344 ret = __add_prelim_ref(prefs, ref->root, info_key, 345 ref->level + 1, ref->parent, 346 node->bytenr, 347 node->ref_mod * sgn); 348 break; 349 } 350 case BTRFS_EXTENT_DATA_REF_KEY: { 351 struct btrfs_delayed_data_ref *ref; 352 struct btrfs_key key; 353 354 ref = btrfs_delayed_node_to_data_ref(node); 355 356 key.objectid = ref->objectid; 357 key.type = BTRFS_EXTENT_DATA_KEY; 358 key.offset = ref->offset; 359 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0, 360 node->bytenr, 361 node->ref_mod * sgn); 362 break; 363 } 364 case BTRFS_SHARED_DATA_REF_KEY: { 365 struct btrfs_delayed_data_ref *ref; 366 struct btrfs_key key; 367 368 ref = btrfs_delayed_node_to_data_ref(node); 369 370 key.objectid = ref->objectid; 371 key.type = BTRFS_EXTENT_DATA_KEY; 372 key.offset = ref->offset; 373 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 374 ref->parent, node->bytenr, 375 node->ref_mod * sgn); 376 break; 377 } 378 default: 379 WARN_ON(1); 380 } 381 BUG_ON(ret); 382 } 383 384 return 0; 385 } 386 387 /* 388 * add all inline backrefs for bytenr to the list 389 */ 390 static int __add_inline_refs(struct btrfs_fs_info *fs_info, 391 struct btrfs_path *path, u64 bytenr, 392 struct btrfs_key *info_key, int *info_level, 393 struct list_head *prefs) 394 { 395 int ret = 0; 396 int slot; 397 struct extent_buffer *leaf; 398 struct btrfs_key key; 399 unsigned long ptr; 400 unsigned long end; 401 struct btrfs_extent_item *ei; 402 u64 flags; 403 u64 item_size; 404 405 /* 406 * enumerate all inline refs 407 */ 408 leaf = path->nodes[0]; 409 slot = path->slots[0] - 1; 410 411 item_size = btrfs_item_size_nr(leaf, slot); 412 BUG_ON(item_size < sizeof(*ei)); 413 414 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); 415 flags = btrfs_extent_flags(leaf, ei); 416 417 ptr = (unsigned long)(ei + 1); 418 end = (unsigned long)ei + item_size; 419 420 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { 421 struct btrfs_tree_block_info *info; 422 struct btrfs_disk_key disk_key; 423 424 info = (struct btrfs_tree_block_info *)ptr; 425 *info_level = btrfs_tree_block_level(leaf, info); 426 btrfs_tree_block_key(leaf, info, &disk_key); 427 btrfs_disk_key_to_cpu(info_key, &disk_key); 428 ptr += sizeof(struct btrfs_tree_block_info); 429 BUG_ON(ptr > end); 430 } else { 431 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA)); 432 } 433 434 while (ptr < end) { 435 struct btrfs_extent_inline_ref *iref; 436 u64 offset; 437 int type; 438 439 iref = (struct btrfs_extent_inline_ref *)ptr; 440 type = btrfs_extent_inline_ref_type(leaf, iref); 441 offset = btrfs_extent_inline_ref_offset(leaf, iref); 442 443 switch (type) { 444 case BTRFS_SHARED_BLOCK_REF_KEY: 445 ret = __add_prelim_ref(prefs, 0, info_key, 446 *info_level + 1, offset, 447 bytenr, 1); 448 break; 449 case BTRFS_SHARED_DATA_REF_KEY: { 450 struct btrfs_shared_data_ref *sdref; 451 int count; 452 453 sdref = (struct btrfs_shared_data_ref *)(iref + 1); 454 count = btrfs_shared_data_ref_count(leaf, sdref); 455 ret = __add_prelim_ref(prefs, 0, NULL, 0, offset, 456 bytenr, count); 457 break; 458 } 459 case BTRFS_TREE_BLOCK_REF_KEY: 460 ret = __add_prelim_ref(prefs, offset, info_key, 461 *info_level + 1, 0, bytenr, 1); 462 break; 463 case BTRFS_EXTENT_DATA_REF_KEY: { 464 struct btrfs_extent_data_ref *dref; 465 int count; 466 u64 root; 467 468 dref = (struct btrfs_extent_data_ref *)(&iref->offset); 469 count = btrfs_extent_data_ref_count(leaf, dref); 470 key.objectid = btrfs_extent_data_ref_objectid(leaf, 471 dref); 472 key.type = BTRFS_EXTENT_DATA_KEY; 473 key.offset = btrfs_extent_data_ref_offset(leaf, dref); 474 root = btrfs_extent_data_ref_root(leaf, dref); 475 ret = __add_prelim_ref(prefs, root, &key, 0, 0, bytenr, 476 count); 477 break; 478 } 479 default: 480 WARN_ON(1); 481 } 482 BUG_ON(ret); 483 ptr += btrfs_extent_inline_ref_size(type); 484 } 485 486 return 0; 487 } 488 489 /* 490 * add all non-inline backrefs for bytenr to the list 491 */ 492 static int __add_keyed_refs(struct btrfs_fs_info *fs_info, 493 struct btrfs_path *path, u64 bytenr, 494 struct btrfs_key *info_key, int info_level, 495 struct list_head *prefs) 496 { 497 struct btrfs_root *extent_root = fs_info->extent_root; 498 int ret; 499 int slot; 500 struct extent_buffer *leaf; 501 struct btrfs_key key; 502 503 while (1) { 504 ret = btrfs_next_item(extent_root, path); 505 if (ret < 0) 506 break; 507 if (ret) { 508 ret = 0; 509 break; 510 } 511 512 slot = path->slots[0]; 513 leaf = path->nodes[0]; 514 btrfs_item_key_to_cpu(leaf, &key, slot); 515 516 if (key.objectid != bytenr) 517 break; 518 if (key.type < BTRFS_TREE_BLOCK_REF_KEY) 519 continue; 520 if (key.type > BTRFS_SHARED_DATA_REF_KEY) 521 break; 522 523 switch (key.type) { 524 case BTRFS_SHARED_BLOCK_REF_KEY: 525 ret = __add_prelim_ref(prefs, 0, info_key, 526 info_level + 1, key.offset, 527 bytenr, 1); 528 break; 529 case BTRFS_SHARED_DATA_REF_KEY: { 530 struct btrfs_shared_data_ref *sdref; 531 int count; 532 533 sdref = btrfs_item_ptr(leaf, slot, 534 struct btrfs_shared_data_ref); 535 count = btrfs_shared_data_ref_count(leaf, sdref); 536 ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset, 537 bytenr, count); 538 break; 539 } 540 case BTRFS_TREE_BLOCK_REF_KEY: 541 ret = __add_prelim_ref(prefs, key.offset, info_key, 542 info_level + 1, 0, bytenr, 1); 543 break; 544 case BTRFS_EXTENT_DATA_REF_KEY: { 545 struct btrfs_extent_data_ref *dref; 546 int count; 547 u64 root; 548 549 dref = btrfs_item_ptr(leaf, slot, 550 struct btrfs_extent_data_ref); 551 count = btrfs_extent_data_ref_count(leaf, dref); 552 key.objectid = btrfs_extent_data_ref_objectid(leaf, 553 dref); 554 key.type = BTRFS_EXTENT_DATA_KEY; 555 key.offset = btrfs_extent_data_ref_offset(leaf, dref); 556 root = btrfs_extent_data_ref_root(leaf, dref); 557 ret = __add_prelim_ref(prefs, root, &key, 0, 0, 558 bytenr, count); 559 break; 560 } 561 default: 562 WARN_ON(1); 563 } 564 BUG_ON(ret); 565 } 566 567 return ret; 568 } 569 570 /* 571 * this adds all existing backrefs (inline backrefs, backrefs and delayed 572 * refs) for the given bytenr to the refs list, merges duplicates and resolves 573 * indirect refs to their parent bytenr. 574 * When roots are found, they're added to the roots list 575 * 576 * FIXME some caching might speed things up 577 */ 578 static int find_parent_nodes(struct btrfs_trans_handle *trans, 579 struct btrfs_fs_info *fs_info, u64 bytenr, 580 u64 seq, struct ulist *refs, struct ulist *roots) 581 { 582 struct btrfs_key key; 583 struct btrfs_path *path; 584 struct btrfs_key info_key = { 0 }; 585 struct btrfs_delayed_ref_root *delayed_refs = NULL; 586 struct btrfs_delayed_ref_head *head; 587 int info_level = 0; 588 int ret; 589 struct list_head prefs_delayed; 590 struct list_head prefs; 591 struct __prelim_ref *ref; 592 593 INIT_LIST_HEAD(&prefs); 594 INIT_LIST_HEAD(&prefs_delayed); 595 596 key.objectid = bytenr; 597 key.type = BTRFS_EXTENT_ITEM_KEY; 598 key.offset = (u64)-1; 599 600 path = btrfs_alloc_path(); 601 if (!path) 602 return -ENOMEM; 603 604 /* 605 * grab both a lock on the path and a lock on the delayed ref head. 606 * We need both to get a consistent picture of how the refs look 607 * at a specified point in time 608 */ 609 again: 610 head = NULL; 611 612 ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0); 613 if (ret < 0) 614 goto out; 615 BUG_ON(ret == 0); 616 617 /* 618 * look if there are updates for this ref queued and lock the head 619 */ 620 delayed_refs = &trans->transaction->delayed_refs; 621 spin_lock(&delayed_refs->lock); 622 head = btrfs_find_delayed_ref_head(trans, bytenr); 623 if (head) { 624 if (!mutex_trylock(&head->mutex)) { 625 atomic_inc(&head->node.refs); 626 spin_unlock(&delayed_refs->lock); 627 628 btrfs_release_path(path); 629 630 /* 631 * Mutex was contended, block until it's 632 * released and try again 633 */ 634 mutex_lock(&head->mutex); 635 mutex_unlock(&head->mutex); 636 btrfs_put_delayed_ref(&head->node); 637 goto again; 638 } 639 ret = __add_delayed_refs(head, seq, &info_key, &prefs_delayed); 640 if (ret) { 641 spin_unlock(&delayed_refs->lock); 642 goto out; 643 } 644 } 645 spin_unlock(&delayed_refs->lock); 646 647 if (path->slots[0]) { 648 struct extent_buffer *leaf; 649 int slot; 650 651 leaf = path->nodes[0]; 652 slot = path->slots[0] - 1; 653 btrfs_item_key_to_cpu(leaf, &key, slot); 654 if (key.objectid == bytenr && 655 key.type == BTRFS_EXTENT_ITEM_KEY) { 656 ret = __add_inline_refs(fs_info, path, bytenr, 657 &info_key, &info_level, &prefs); 658 if (ret) 659 goto out; 660 ret = __add_keyed_refs(fs_info, path, bytenr, &info_key, 661 info_level, &prefs); 662 if (ret) 663 goto out; 664 } 665 } 666 btrfs_release_path(path); 667 668 /* 669 * when adding the delayed refs above, the info_key might not have 670 * been known yet. Go over the list and replace the missing keys 671 */ 672 list_for_each_entry(ref, &prefs_delayed, list) { 673 if ((ref->key.offset | ref->key.type | ref->key.objectid) == 0) 674 memcpy(&ref->key, &info_key, sizeof(ref->key)); 675 } 676 list_splice_init(&prefs_delayed, &prefs); 677 678 ret = __merge_refs(&prefs, 1); 679 if (ret) 680 goto out; 681 682 ret = __resolve_indirect_refs(fs_info, &prefs); 683 if (ret) 684 goto out; 685 686 ret = __merge_refs(&prefs, 2); 687 if (ret) 688 goto out; 689 690 while (!list_empty(&prefs)) { 691 ref = list_first_entry(&prefs, struct __prelim_ref, list); 692 list_del(&ref->list); 693 if (ref->count < 0) 694 WARN_ON(1); 695 if (ref->count && ref->root_id && ref->parent == 0) { 696 /* no parent == root of tree */ 697 ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS); 698 BUG_ON(ret < 0); 699 } 700 if (ref->count && ref->parent) { 701 ret = ulist_add(refs, ref->parent, 0, GFP_NOFS); 702 BUG_ON(ret < 0); 703 } 704 kfree(ref); 705 } 706 707 out: 708 if (head) 709 mutex_unlock(&head->mutex); 710 btrfs_free_path(path); 711 while (!list_empty(&prefs)) { 712 ref = list_first_entry(&prefs, struct __prelim_ref, list); 713 list_del(&ref->list); 714 kfree(ref); 715 } 716 while (!list_empty(&prefs_delayed)) { 717 ref = list_first_entry(&prefs_delayed, struct __prelim_ref, 718 list); 719 list_del(&ref->list); 720 kfree(ref); 721 } 722 723 return ret; 724 } 725 726 /* 727 * Finds all leafs with a reference to the specified combination of bytenr and 728 * offset. key_list_head will point to a list of corresponding keys (caller must 729 * free each list element). The leafs will be stored in the leafs ulist, which 730 * must be freed with ulist_free. 731 * 732 * returns 0 on success, <0 on error 733 */ 734 static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, 735 struct btrfs_fs_info *fs_info, u64 bytenr, 736 u64 num_bytes, u64 seq, struct ulist **leafs) 737 { 738 struct ulist *tmp; 739 int ret; 740 741 tmp = ulist_alloc(GFP_NOFS); 742 if (!tmp) 743 return -ENOMEM; 744 *leafs = ulist_alloc(GFP_NOFS); 745 if (!*leafs) { 746 ulist_free(tmp); 747 return -ENOMEM; 748 } 749 750 ret = find_parent_nodes(trans, fs_info, bytenr, seq, *leafs, tmp); 751 ulist_free(tmp); 752 753 if (ret < 0 && ret != -ENOENT) { 754 ulist_free(*leafs); 755 return ret; 756 } 757 758 return 0; 759 } 760 761 /* 762 * walk all backrefs for a given extent to find all roots that reference this 763 * extent. Walking a backref means finding all extents that reference this 764 * extent and in turn walk the backrefs of those, too. Naturally this is a 765 * recursive process, but here it is implemented in an iterative fashion: We 766 * find all referencing extents for the extent in question and put them on a 767 * list. In turn, we find all referencing extents for those, further appending 768 * to the list. The way we iterate the list allows adding more elements after 769 * the current while iterating. The process stops when we reach the end of the 770 * list. Found roots are added to the roots list. 771 * 772 * returns 0 on success, < 0 on error. 773 */ 774 int btrfs_find_all_roots(struct btrfs_trans_handle *trans, 775 struct btrfs_fs_info *fs_info, u64 bytenr, 776 u64 num_bytes, u64 seq, struct ulist **roots) 777 { 778 struct ulist *tmp; 779 struct ulist_node *node = NULL; 780 int ret; 781 782 tmp = ulist_alloc(GFP_NOFS); 783 if (!tmp) 784 return -ENOMEM; 785 *roots = ulist_alloc(GFP_NOFS); 786 if (!*roots) { 787 ulist_free(tmp); 788 return -ENOMEM; 789 } 790 791 while (1) { 792 ret = find_parent_nodes(trans, fs_info, bytenr, seq, 793 tmp, *roots); 794 if (ret < 0 && ret != -ENOENT) { 795 ulist_free(tmp); 796 ulist_free(*roots); 797 return ret; 798 } 799 node = ulist_next(tmp, node); 800 if (!node) 801 break; 802 bytenr = node->val; 803 } 804 805 ulist_free(tmp); 806 return 0; 807 } 808 809 810 static int __inode_info(u64 inum, u64 ioff, u8 key_type, 811 struct btrfs_root *fs_root, struct btrfs_path *path, 812 struct btrfs_key *found_key) 813 { 814 int ret; 815 struct btrfs_key key; 816 struct extent_buffer *eb; 817 818 key.type = key_type; 819 key.objectid = inum; 820 key.offset = ioff; 821 822 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0); 823 if (ret < 0) 824 return ret; 825 826 eb = path->nodes[0]; 827 if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { 828 ret = btrfs_next_leaf(fs_root, path); 829 if (ret) 830 return ret; 831 eb = path->nodes[0]; 832 } 833 834 btrfs_item_key_to_cpu(eb, found_key, path->slots[0]); 835 if (found_key->type != key.type || found_key->objectid != key.objectid) 836 return 1; 837 838 return 0; 839 } 840 841 /* 842 * this makes the path point to (inum INODE_ITEM ioff) 843 */ 844 int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, 845 struct btrfs_path *path) 846 { 847 struct btrfs_key key; 848 return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path, 849 &key); 850 } 851 852 static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, 853 struct btrfs_path *path, 854 struct btrfs_key *found_key) 855 { 856 return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path, 857 found_key); 858 } 859 860 /* 861 * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements 862 * of the path are separated by '/' and the path is guaranteed to be 863 * 0-terminated. the path is only given within the current file system. 864 * Therefore, it never starts with a '/'. the caller is responsible to provide 865 * "size" bytes in "dest". the dest buffer will be filled backwards. finally, 866 * the start point of the resulting string is returned. this pointer is within 867 * dest, normally. 868 * in case the path buffer would overflow, the pointer is decremented further 869 * as if output was written to the buffer, though no more output is actually 870 * generated. that way, the caller can determine how much space would be 871 * required for the path to fit into the buffer. in that case, the returned 872 * value will be smaller than dest. callers must check this! 873 */ 874 static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path, 875 struct btrfs_inode_ref *iref, 876 struct extent_buffer *eb_in, u64 parent, 877 char *dest, u32 size) 878 { 879 u32 len; 880 int slot; 881 u64 next_inum; 882 int ret; 883 s64 bytes_left = size - 1; 884 struct extent_buffer *eb = eb_in; 885 struct btrfs_key found_key; 886 887 if (bytes_left >= 0) 888 dest[bytes_left] = '\0'; 889 890 while (1) { 891 len = btrfs_inode_ref_name_len(eb, iref); 892 bytes_left -= len; 893 if (bytes_left >= 0) 894 read_extent_buffer(eb, dest + bytes_left, 895 (unsigned long)(iref + 1), len); 896 if (eb != eb_in) 897 free_extent_buffer(eb); 898 ret = inode_ref_info(parent, 0, fs_root, path, &found_key); 899 if (ret > 0) 900 ret = -ENOENT; 901 if (ret) 902 break; 903 next_inum = found_key.offset; 904 905 /* regular exit ahead */ 906 if (parent == next_inum) 907 break; 908 909 slot = path->slots[0]; 910 eb = path->nodes[0]; 911 /* make sure we can use eb after releasing the path */ 912 if (eb != eb_in) 913 atomic_inc(&eb->refs); 914 btrfs_release_path(path); 915 916 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); 917 parent = next_inum; 918 --bytes_left; 919 if (bytes_left >= 0) 920 dest[bytes_left] = '/'; 921 } 922 923 btrfs_release_path(path); 924 925 if (ret) 926 return ERR_PTR(ret); 927 928 return dest + bytes_left; 929 } 930 931 /* 932 * this makes the path point to (logical EXTENT_ITEM *) 933 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for 934 * tree blocks and <0 on error. 935 */ 936 int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, 937 struct btrfs_path *path, struct btrfs_key *found_key) 938 { 939 int ret; 940 u64 flags; 941 u32 item_size; 942 struct extent_buffer *eb; 943 struct btrfs_extent_item *ei; 944 struct btrfs_key key; 945 946 key.type = BTRFS_EXTENT_ITEM_KEY; 947 key.objectid = logical; 948 key.offset = (u64)-1; 949 950 ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); 951 if (ret < 0) 952 return ret; 953 ret = btrfs_previous_item(fs_info->extent_root, path, 954 0, BTRFS_EXTENT_ITEM_KEY); 955 if (ret < 0) 956 return ret; 957 958 btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]); 959 if (found_key->type != BTRFS_EXTENT_ITEM_KEY || 960 found_key->objectid > logical || 961 found_key->objectid + found_key->offset <= logical) { 962 pr_debug("logical %llu is not within any extent\n", 963 (unsigned long long)logical); 964 return -ENOENT; 965 } 966 967 eb = path->nodes[0]; 968 item_size = btrfs_item_size_nr(eb, path->slots[0]); 969 BUG_ON(item_size < sizeof(*ei)); 970 971 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); 972 flags = btrfs_extent_flags(eb, ei); 973 974 pr_debug("logical %llu is at position %llu within the extent (%llu " 975 "EXTENT_ITEM %llu) flags %#llx size %u\n", 976 (unsigned long long)logical, 977 (unsigned long long)(logical - found_key->objectid), 978 (unsigned long long)found_key->objectid, 979 (unsigned long long)found_key->offset, 980 (unsigned long long)flags, item_size); 981 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) 982 return BTRFS_EXTENT_FLAG_TREE_BLOCK; 983 if (flags & BTRFS_EXTENT_FLAG_DATA) 984 return BTRFS_EXTENT_FLAG_DATA; 985 986 return -EIO; 987 } 988 989 /* 990 * helper function to iterate extent inline refs. ptr must point to a 0 value 991 * for the first call and may be modified. it is used to track state. 992 * if more refs exist, 0 is returned and the next call to 993 * __get_extent_inline_ref must pass the modified ptr parameter to get the 994 * next ref. after the last ref was processed, 1 is returned. 995 * returns <0 on error 996 */ 997 static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb, 998 struct btrfs_extent_item *ei, u32 item_size, 999 struct btrfs_extent_inline_ref **out_eiref, 1000 int *out_type) 1001 { 1002 unsigned long end; 1003 u64 flags; 1004 struct btrfs_tree_block_info *info; 1005 1006 if (!*ptr) { 1007 /* first call */ 1008 flags = btrfs_extent_flags(eb, ei); 1009 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { 1010 info = (struct btrfs_tree_block_info *)(ei + 1); 1011 *out_eiref = 1012 (struct btrfs_extent_inline_ref *)(info + 1); 1013 } else { 1014 *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1); 1015 } 1016 *ptr = (unsigned long)*out_eiref; 1017 if ((void *)*ptr >= (void *)ei + item_size) 1018 return -ENOENT; 1019 } 1020 1021 end = (unsigned long)ei + item_size; 1022 *out_eiref = (struct btrfs_extent_inline_ref *)*ptr; 1023 *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref); 1024 1025 *ptr += btrfs_extent_inline_ref_size(*out_type); 1026 WARN_ON(*ptr > end); 1027 if (*ptr == end) 1028 return 1; /* last */ 1029 1030 return 0; 1031 } 1032 1033 /* 1034 * reads the tree block backref for an extent. tree level and root are returned 1035 * through out_level and out_root. ptr must point to a 0 value for the first 1036 * call and may be modified (see __get_extent_inline_ref comment). 1037 * returns 0 if data was provided, 1 if there was no more data to provide or 1038 * <0 on error. 1039 */ 1040 int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb, 1041 struct btrfs_extent_item *ei, u32 item_size, 1042 u64 *out_root, u8 *out_level) 1043 { 1044 int ret; 1045 int type; 1046 struct btrfs_tree_block_info *info; 1047 struct btrfs_extent_inline_ref *eiref; 1048 1049 if (*ptr == (unsigned long)-1) 1050 return 1; 1051 1052 while (1) { 1053 ret = __get_extent_inline_ref(ptr, eb, ei, item_size, 1054 &eiref, &type); 1055 if (ret < 0) 1056 return ret; 1057 1058 if (type == BTRFS_TREE_BLOCK_REF_KEY || 1059 type == BTRFS_SHARED_BLOCK_REF_KEY) 1060 break; 1061 1062 if (ret == 1) 1063 return 1; 1064 } 1065 1066 /* we can treat both ref types equally here */ 1067 info = (struct btrfs_tree_block_info *)(ei + 1); 1068 *out_root = btrfs_extent_inline_ref_offset(eb, eiref); 1069 *out_level = btrfs_tree_block_level(eb, info); 1070 1071 if (ret == 1) 1072 *ptr = (unsigned long)-1; 1073 1074 return 0; 1075 } 1076 1077 static int iterate_leaf_refs(struct btrfs_fs_info *fs_info, 1078 struct btrfs_path *path, u64 logical, 1079 u64 orig_extent_item_objectid, 1080 u64 extent_item_pos, u64 root, 1081 iterate_extent_inodes_t *iterate, void *ctx) 1082 { 1083 u64 disk_byte; 1084 struct btrfs_key key; 1085 struct btrfs_file_extent_item *fi; 1086 struct extent_buffer *eb; 1087 int slot; 1088 int nritems; 1089 int ret = 0; 1090 int extent_type; 1091 u64 data_offset; 1092 u64 data_len; 1093 1094 eb = read_tree_block(fs_info->tree_root, logical, 1095 fs_info->tree_root->leafsize, 0); 1096 if (!eb) 1097 return -EIO; 1098 1099 /* 1100 * from the shared data ref, we only have the leaf but we need 1101 * the key. thus, we must look into all items and see that we 1102 * find one (some) with a reference to our extent item. 1103 */ 1104 nritems = btrfs_header_nritems(eb); 1105 for (slot = 0; slot < nritems; ++slot) { 1106 btrfs_item_key_to_cpu(eb, &key, slot); 1107 if (key.type != BTRFS_EXTENT_DATA_KEY) 1108 continue; 1109 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); 1110 extent_type = btrfs_file_extent_type(eb, fi); 1111 if (extent_type == BTRFS_FILE_EXTENT_INLINE) 1112 continue; 1113 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */ 1114 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); 1115 if (disk_byte != orig_extent_item_objectid) 1116 continue; 1117 1118 data_offset = btrfs_file_extent_offset(eb, fi); 1119 data_len = btrfs_file_extent_num_bytes(eb, fi); 1120 1121 if (extent_item_pos < data_offset || 1122 extent_item_pos >= data_offset + data_len) 1123 continue; 1124 1125 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), " 1126 "root %llu\n", orig_extent_item_objectid, 1127 key.objectid, key.offset, root); 1128 ret = iterate(key.objectid, 1129 key.offset + (extent_item_pos - data_offset), 1130 root, ctx); 1131 if (ret) { 1132 pr_debug("stopping iteration because ret=%d\n", ret); 1133 break; 1134 } 1135 } 1136 1137 free_extent_buffer(eb); 1138 1139 return ret; 1140 } 1141 1142 /* 1143 * calls iterate() for every inode that references the extent identified by 1144 * the given parameters. 1145 * when the iterator function returns a non-zero value, iteration stops. 1146 * path is guaranteed to be in released state when iterate() is called. 1147 */ 1148 int iterate_extent_inodes(struct btrfs_fs_info *fs_info, 1149 struct btrfs_path *path, 1150 u64 extent_item_objectid, u64 extent_item_pos, 1151 iterate_extent_inodes_t *iterate, void *ctx) 1152 { 1153 int ret; 1154 struct list_head data_refs = LIST_HEAD_INIT(data_refs); 1155 struct list_head shared_refs = LIST_HEAD_INIT(shared_refs); 1156 struct btrfs_trans_handle *trans; 1157 struct ulist *refs; 1158 struct ulist *roots; 1159 struct ulist_node *ref_node = NULL; 1160 struct ulist_node *root_node = NULL; 1161 struct seq_list seq_elem; 1162 struct btrfs_delayed_ref_root *delayed_refs; 1163 1164 trans = btrfs_join_transaction(fs_info->extent_root); 1165 if (IS_ERR(trans)) 1166 return PTR_ERR(trans); 1167 1168 pr_debug("resolving all inodes for extent %llu\n", 1169 extent_item_objectid); 1170 1171 delayed_refs = &trans->transaction->delayed_refs; 1172 spin_lock(&delayed_refs->lock); 1173 btrfs_get_delayed_seq(delayed_refs, &seq_elem); 1174 spin_unlock(&delayed_refs->lock); 1175 1176 ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid, 1177 extent_item_pos, seq_elem.seq, 1178 &refs); 1179 1180 if (ret) 1181 goto out; 1182 1183 while (!ret && (ref_node = ulist_next(refs, ref_node))) { 1184 ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, -1, 1185 seq_elem.seq, &roots); 1186 if (ret) 1187 break; 1188 while (!ret && (root_node = ulist_next(roots, root_node))) { 1189 pr_debug("root %llu references leaf %llu\n", 1190 root_node->val, ref_node->val); 1191 ret = iterate_leaf_refs(fs_info, path, ref_node->val, 1192 extent_item_objectid, 1193 extent_item_pos, root_node->val, 1194 iterate, ctx); 1195 } 1196 } 1197 1198 ulist_free(refs); 1199 ulist_free(roots); 1200 out: 1201 btrfs_put_delayed_seq(delayed_refs, &seq_elem); 1202 btrfs_end_transaction(trans, fs_info->extent_root); 1203 return ret; 1204 } 1205 1206 int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info, 1207 struct btrfs_path *path, 1208 iterate_extent_inodes_t *iterate, void *ctx) 1209 { 1210 int ret; 1211 u64 extent_item_pos; 1212 struct btrfs_key found_key; 1213 1214 ret = extent_from_logical(fs_info, logical, path, 1215 &found_key); 1216 btrfs_release_path(path); 1217 if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) 1218 ret = -EINVAL; 1219 if (ret < 0) 1220 return ret; 1221 1222 extent_item_pos = logical - found_key.objectid; 1223 ret = iterate_extent_inodes(fs_info, path, found_key.objectid, 1224 extent_item_pos, iterate, ctx); 1225 1226 return ret; 1227 } 1228 1229 static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, 1230 struct btrfs_path *path, 1231 iterate_irefs_t *iterate, void *ctx) 1232 { 1233 int ret; 1234 int slot; 1235 u32 cur; 1236 u32 len; 1237 u32 name_len; 1238 u64 parent = 0; 1239 int found = 0; 1240 struct extent_buffer *eb; 1241 struct btrfs_item *item; 1242 struct btrfs_inode_ref *iref; 1243 struct btrfs_key found_key; 1244 1245 while (1) { 1246 ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path, 1247 &found_key); 1248 if (ret < 0) 1249 break; 1250 if (ret) { 1251 ret = found ? 0 : -ENOENT; 1252 break; 1253 } 1254 ++found; 1255 1256 parent = found_key.offset; 1257 slot = path->slots[0]; 1258 eb = path->nodes[0]; 1259 /* make sure we can use eb after releasing the path */ 1260 atomic_inc(&eb->refs); 1261 btrfs_release_path(path); 1262 1263 item = btrfs_item_nr(eb, slot); 1264 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); 1265 1266 for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) { 1267 name_len = btrfs_inode_ref_name_len(eb, iref); 1268 /* path must be released before calling iterate()! */ 1269 pr_debug("following ref at offset %u for inode %llu in " 1270 "tree %llu\n", cur, 1271 (unsigned long long)found_key.objectid, 1272 (unsigned long long)fs_root->objectid); 1273 ret = iterate(parent, iref, eb, ctx); 1274 if (ret) { 1275 free_extent_buffer(eb); 1276 break; 1277 } 1278 len = sizeof(*iref) + name_len; 1279 iref = (struct btrfs_inode_ref *)((char *)iref + len); 1280 } 1281 free_extent_buffer(eb); 1282 } 1283 1284 btrfs_release_path(path); 1285 1286 return ret; 1287 } 1288 1289 /* 1290 * returns 0 if the path could be dumped (probably truncated) 1291 * returns <0 in case of an error 1292 */ 1293 static int inode_to_path(u64 inum, struct btrfs_inode_ref *iref, 1294 struct extent_buffer *eb, void *ctx) 1295 { 1296 struct inode_fs_paths *ipath = ctx; 1297 char *fspath; 1298 char *fspath_min; 1299 int i = ipath->fspath->elem_cnt; 1300 const int s_ptr = sizeof(char *); 1301 u32 bytes_left; 1302 1303 bytes_left = ipath->fspath->bytes_left > s_ptr ? 1304 ipath->fspath->bytes_left - s_ptr : 0; 1305 1306 fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr; 1307 fspath = iref_to_path(ipath->fs_root, ipath->btrfs_path, iref, eb, 1308 inum, fspath_min, bytes_left); 1309 if (IS_ERR(fspath)) 1310 return PTR_ERR(fspath); 1311 1312 if (fspath > fspath_min) { 1313 pr_debug("path resolved: %s\n", fspath); 1314 ipath->fspath->val[i] = (u64)(unsigned long)fspath; 1315 ++ipath->fspath->elem_cnt; 1316 ipath->fspath->bytes_left = fspath - fspath_min; 1317 } else { 1318 pr_debug("missed path, not enough space. missing bytes: %lu, " 1319 "constructed so far: %s\n", 1320 (unsigned long)(fspath_min - fspath), fspath_min); 1321 ++ipath->fspath->elem_missed; 1322 ipath->fspath->bytes_missing += fspath_min - fspath; 1323 ipath->fspath->bytes_left = 0; 1324 } 1325 1326 return 0; 1327 } 1328 1329 /* 1330 * this dumps all file system paths to the inode into the ipath struct, provided 1331 * is has been created large enough. each path is zero-terminated and accessed 1332 * from ipath->fspath->val[i]. 1333 * when it returns, there are ipath->fspath->elem_cnt number of paths available 1334 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the 1335 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise, 1336 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would 1337 * have been needed to return all paths. 1338 */ 1339 int paths_from_inode(u64 inum, struct inode_fs_paths *ipath) 1340 { 1341 return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path, 1342 inode_to_path, ipath); 1343 } 1344 1345 /* 1346 * allocates space to return multiple file system paths for an inode. 1347 * total_bytes to allocate are passed, note that space usable for actual path 1348 * information will be total_bytes - sizeof(struct inode_fs_paths). 1349 * the returned pointer must be freed with free_ipath() in the end. 1350 */ 1351 struct btrfs_data_container *init_data_container(u32 total_bytes) 1352 { 1353 struct btrfs_data_container *data; 1354 size_t alloc_bytes; 1355 1356 alloc_bytes = max_t(size_t, total_bytes, sizeof(*data)); 1357 data = kmalloc(alloc_bytes, GFP_NOFS); 1358 if (!data) 1359 return ERR_PTR(-ENOMEM); 1360 1361 if (total_bytes >= sizeof(*data)) { 1362 data->bytes_left = total_bytes - sizeof(*data); 1363 data->bytes_missing = 0; 1364 } else { 1365 data->bytes_missing = sizeof(*data) - total_bytes; 1366 data->bytes_left = 0; 1367 } 1368 1369 data->elem_cnt = 0; 1370 data->elem_missed = 0; 1371 1372 return data; 1373 } 1374 1375 /* 1376 * allocates space to return multiple file system paths for an inode. 1377 * total_bytes to allocate are passed, note that space usable for actual path 1378 * information will be total_bytes - sizeof(struct inode_fs_paths). 1379 * the returned pointer must be freed with free_ipath() in the end. 1380 */ 1381 struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root, 1382 struct btrfs_path *path) 1383 { 1384 struct inode_fs_paths *ifp; 1385 struct btrfs_data_container *fspath; 1386 1387 fspath = init_data_container(total_bytes); 1388 if (IS_ERR(fspath)) 1389 return (void *)fspath; 1390 1391 ifp = kmalloc(sizeof(*ifp), GFP_NOFS); 1392 if (!ifp) { 1393 kfree(fspath); 1394 return ERR_PTR(-ENOMEM); 1395 } 1396 1397 ifp->btrfs_path = path; 1398 ifp->fspath = fspath; 1399 ifp->fs_root = fs_root; 1400 1401 return ifp; 1402 } 1403 1404 void free_ipath(struct inode_fs_paths *ipath) 1405 { 1406 kfree(ipath); 1407 } 1408