Line data Source code
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 31221 : 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 62394 : if (!btrfs_file_extent_compression(eb, fi) &&
43 31173 : !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 62081 : if (extent_item_pos < data_offset ||
52 30908 : extent_item_pos >= data_offset + data_len)
53 : return 1;
54 30627 : offset = extent_item_pos - data_offset;
55 : }
56 :
57 : e = kmalloc(sizeof(*e), GFP_NOFS);
58 30675 : if (!e)
59 : return -ENOMEM;
60 :
61 30675 : e->next = *eie;
62 30675 : e->inum = key->objectid;
63 30675 : e->offset = key->offset + offset;
64 30675 : *eie = e;
65 :
66 30675 : return 0;
67 : }
68 :
69 : static void free_inode_elem_list(struct extent_inode_elem *eie)
70 : {
71 : struct extent_inode_elem *eie_next;
72 :
73 61322 : for (; eie; eie = eie_next) {
74 30675 : eie_next = eie->next;
75 30675 : kfree(eie);
76 : }
77 : }
78 :
79 6688 : static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte,
80 : u64 extent_item_pos,
81 : struct extent_inode_elem **eie)
82 : {
83 : u64 disk_byte;
84 : struct btrfs_key key;
85 : struct btrfs_file_extent_item *fi;
86 : int slot;
87 : int nritems;
88 : int extent_type;
89 : int ret;
90 :
91 : /*
92 : * from the shared data ref, we only have the leaf but we need
93 : * the key. thus, we must look into all items and see that we
94 : * find one (some) with a reference to our extent item.
95 : */
96 6688 : nritems = btrfs_header_nritems(eb);
97 1195570 : for (slot = 0; slot < nritems; ++slot) {
98 1188882 : btrfs_item_key_to_cpu(eb, &key, slot);
99 1188882 : if (key.type != BTRFS_EXTENT_DATA_KEY)
100 257314 : continue;
101 931568 : fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
102 : extent_type = btrfs_file_extent_type(eb, fi);
103 931568 : if (extent_type == BTRFS_FILE_EXTENT_INLINE)
104 21 : continue;
105 : /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
106 : disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
107 931547 : if (disk_byte != wanted_disk_byte)
108 924859 : continue;
109 :
110 6688 : ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie);
111 6688 : if (ret < 0)
112 : return ret;
113 : }
114 :
115 : return 0;
116 : }
117 :
118 : /*
119 : * this structure records all encountered refs on the way up to the root
120 : */
121 : struct __prelim_ref {
122 : struct list_head list;
123 : u64 root_id;
124 : struct btrfs_key key_for_search;
125 : int level;
126 : int count;
127 : struct extent_inode_elem *inode_list;
128 : u64 parent;
129 : u64 wanted_disk_byte;
130 : };
131 :
132 : static struct kmem_cache *btrfs_prelim_ref_cache;
133 :
134 0 : int __init btrfs_prelim_ref_init(void)
135 : {
136 0 : btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref",
137 : sizeof(struct __prelim_ref),
138 : 0,
139 : SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
140 : NULL);
141 0 : if (!btrfs_prelim_ref_cache)
142 : return -ENOMEM;
143 0 : return 0;
144 : }
145 :
146 0 : void btrfs_prelim_ref_exit(void)
147 : {
148 0 : if (btrfs_prelim_ref_cache)
149 0 : kmem_cache_destroy(btrfs_prelim_ref_cache);
150 0 : }
151 :
152 : /*
153 : * the rules for all callers of this function are:
154 : * - obtaining the parent is the goal
155 : * - if you add a key, you must know that it is a correct key
156 : * - if you cannot add the parent or a correct key, then we will look into the
157 : * block later to set a correct key
158 : *
159 : * delayed refs
160 : * ============
161 : * backref type | shared | indirect | shared | indirect
162 : * information | tree | tree | data | data
163 : * --------------------+--------+----------+--------+----------
164 : * parent logical | y | - | - | -
165 : * key to resolve | - | y | y | y
166 : * tree block logical | - | - | - | -
167 : * root for resolving | y | y | y | y
168 : *
169 : * - column 1: we've the parent -> done
170 : * - column 2, 3, 4: we use the key to find the parent
171 : *
172 : * on disk refs (inline or keyed)
173 : * ==============================
174 : * backref type | shared | indirect | shared | indirect
175 : * information | tree | tree | data | data
176 : * --------------------+--------+----------+--------+----------
177 : * parent logical | y | - | y | -
178 : * key to resolve | - | - | - | y
179 : * tree block logical | y | y | y | y
180 : * root for resolving | - | y | y | y
181 : *
182 : * - column 1, 3: we've the parent -> done
183 : * - column 2: we take the first key from the block to find the parent
184 : * (see __add_missing_keys)
185 : * - column 4: we use the key to find the parent
186 : *
187 : * additional information that's available but not required to find the parent
188 : * block might help in merging entries to gain some speed.
189 : */
190 :
191 1197405 : static int __add_prelim_ref(struct list_head *head, u64 root_id,
192 : struct btrfs_key *key, int level,
193 : u64 parent, u64 wanted_disk_byte, int count,
194 : gfp_t gfp_mask)
195 : {
196 : struct __prelim_ref *ref;
197 :
198 1197405 : if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID)
199 : return 0;
200 :
201 1197398 : ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask);
202 1197398 : if (!ref)
203 : return -ENOMEM;
204 :
205 1197398 : ref->root_id = root_id;
206 1197398 : if (key)
207 27682 : ref->key_for_search = *key;
208 : else
209 1169716 : memset(&ref->key_for_search, 0, sizeof(ref->key_for_search));
210 :
211 1197398 : ref->inode_list = NULL;
212 1197398 : ref->level = level;
213 1197398 : ref->count = count;
214 1197398 : ref->parent = parent;
215 1197398 : ref->wanted_disk_byte = wanted_disk_byte;
216 1197398 : list_add_tail(&ref->list, head);
217 :
218 1197398 : return 0;
219 : }
220 :
221 608122 : static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
222 : struct ulist *parents, struct __prelim_ref *ref,
223 : int level, u64 time_seq, const u64 *extent_item_pos,
224 : u64 total_refs)
225 : {
226 : int ret = 0;
227 : int slot;
228 : struct extent_buffer *eb;
229 : struct btrfs_key key;
230 : struct btrfs_key *key_for_search = &ref->key_for_search;
231 : struct btrfs_file_extent_item *fi;
232 608122 : struct extent_inode_elem *eie = NULL, *old = NULL;
233 : u64 disk_byte;
234 608122 : u64 wanted_disk_byte = ref->wanted_disk_byte;
235 : u64 count = 0;
236 :
237 608122 : if (level != 0) {
238 582104 : eb = path->nodes[level];
239 582104 : ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
240 582104 : if (ret < 0)
241 0 : return ret;
242 : return 0;
243 : }
244 :
245 : /*
246 : * We normally enter this function with the path already pointing to
247 : * the first item to check. But sometimes, we may enter it with
248 : * slot==nritems. In that case, go to the next leaf before we continue.
249 : */
250 52036 : if (path->slots[0] >= btrfs_header_nritems(path->nodes[0]))
251 3 : ret = btrfs_next_old_leaf(root, path, time_seq);
252 :
253 4257641 : while (!ret && count < total_refs) {
254 4233147 : eb = path->nodes[0];
255 4233147 : slot = path->slots[0];
256 :
257 4233147 : btrfs_item_key_to_cpu(eb, &key, slot);
258 :
259 8464770 : if (key.objectid != key_for_search->objectid ||
260 4231623 : key.type != BTRFS_EXTENT_DATA_KEY)
261 : break;
262 :
263 4231623 : fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
264 : disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
265 :
266 4231623 : if (disk_byte == wanted_disk_byte) {
267 26873 : eie = NULL;
268 26873 : old = NULL;
269 26873 : count++;
270 26873 : if (extent_item_pos) {
271 24533 : ret = check_extent_in_eb(&key, eb, fi,
272 : *extent_item_pos,
273 : &eie);
274 24533 : if (ret < 0)
275 : break;
276 : }
277 26873 : if (ret > 0)
278 : goto next;
279 26328 : ret = ulist_add_merge_ptr(parents, eb->start,
280 : eie, (void **)&old, GFP_NOFS);
281 26328 : if (ret < 0)
282 : break;
283 26328 : if (!ret && extent_item_pos) {
284 12 : while (old->next)
285 0 : old = old->next;
286 12 : old->next = eie;
287 : }
288 26328 : eie = NULL;
289 : }
290 : next:
291 4231623 : ret = btrfs_next_old_item(root, path, time_seq);
292 : }
293 :
294 26018 : if (ret > 0)
295 : ret = 0;
296 25353 : else if (ret < 0)
297 0 : free_inode_elem_list(eie);
298 26018 : return ret;
299 : }
300 :
301 : /*
302 : * resolve an indirect backref in the form (root_id, key, level)
303 : * to a logical address
304 : */
305 1187601 : static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
306 : struct btrfs_path *path, u64 time_seq,
307 : struct __prelim_ref *ref,
308 : struct ulist *parents,
309 : const u64 *extent_item_pos, u64 total_refs)
310 : {
311 : struct btrfs_root *root;
312 : struct btrfs_key root_key;
313 : struct extent_buffer *eb;
314 : int ret = 0;
315 : int root_level;
316 1187601 : int level = ref->level;
317 : int index;
318 :
319 1187601 : root_key.objectid = ref->root_id;
320 1187601 : root_key.type = BTRFS_ROOT_ITEM_KEY;
321 1187601 : root_key.offset = (u64)-1;
322 :
323 1187601 : index = srcu_read_lock(&fs_info->subvol_srcu);
324 :
325 : root = btrfs_read_fs_root_no_name(fs_info, &root_key);
326 1187601 : if (IS_ERR(root)) {
327 : srcu_read_unlock(&fs_info->subvol_srcu, index);
328 0 : ret = PTR_ERR(root);
329 0 : goto out;
330 : }
331 :
332 1187601 : if (path->search_commit_root)
333 2349746 : root_level = btrfs_header_level(root->commit_root);
334 : else
335 12728 : root_level = btrfs_old_root_level(root, time_seq);
336 :
337 1187601 : if (root_level + 1 == level) {
338 : srcu_read_unlock(&fs_info->subvol_srcu, index);
339 : goto out;
340 : }
341 :
342 608122 : path->lowest_level = level;
343 608122 : ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq);
344 :
345 : /* root node has been locked, we can release @subvol_srcu safely here */
346 : srcu_read_unlock(&fs_info->subvol_srcu, index);
347 :
348 608122 : pr_debug("search slot in root %llu (level %d, ref count %d) returned "
349 : "%d for key (%llu %u %llu)\n",
350 : ref->root_id, level, ref->count, ret,
351 : ref->key_for_search.objectid, ref->key_for_search.type,
352 : ref->key_for_search.offset);
353 608122 : if (ret < 0)
354 : goto out;
355 :
356 608122 : eb = path->nodes[level];
357 1216244 : while (!eb) {
358 0 : if (WARN_ON(!level)) {
359 : ret = 1;
360 : goto out;
361 : }
362 0 : level--;
363 0 : eb = path->nodes[level];
364 : }
365 :
366 608122 : ret = add_all_parents(root, path, parents, ref, level, time_seq,
367 : extent_item_pos, total_refs);
368 : out:
369 1187601 : path->lowest_level = 0;
370 1187601 : btrfs_release_path(path);
371 1187601 : return ret;
372 : }
373 :
374 : /*
375 : * resolve all indirect backrefs from the list
376 : */
377 646103 : static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
378 : struct btrfs_path *path, u64 time_seq,
379 : struct list_head *head,
380 : const u64 *extent_item_pos, u64 total_refs)
381 : {
382 : int err;
383 : int ret = 0;
384 : struct __prelim_ref *ref;
385 : struct __prelim_ref *ref_safe;
386 : struct __prelim_ref *new_ref;
387 : struct ulist *parents;
388 : struct ulist_node *node;
389 : struct ulist_iterator uiter;
390 :
391 646103 : parents = ulist_alloc(GFP_NOFS);
392 646103 : if (!parents)
393 : return -ENOMEM;
394 :
395 : /*
396 : * _safe allows us to insert directly after the current item without
397 : * iterating over the newly inserted items.
398 : * we're also allowed to re-assign ref during iteration.
399 : */
400 1843079 : list_for_each_entry_safe(ref, ref_safe, head, list) {
401 1196976 : if (ref->parent) /* already direct */
402 8953 : continue;
403 1188023 : if (ref->count == 0)
404 422 : continue;
405 1187601 : err = __resolve_indirect_ref(fs_info, path, time_seq, ref,
406 : parents, extent_item_pos,
407 : total_refs);
408 : /*
409 : * we can only tolerate ENOENT,otherwise,we should catch error
410 : * and return directly.
411 : */
412 1187601 : if (err == -ENOENT) {
413 0 : continue;
414 1187601 : } else if (err) {
415 : ret = err;
416 : goto out;
417 : }
418 :
419 : /* we put the first parent into the ref at hand */
420 1187601 : ULIST_ITER_INIT(&uiter);
421 1187601 : node = ulist_next(parents, &uiter);
422 1187601 : ref->parent = node ? node->val : 0;
423 1187601 : ref->inode_list = node ?
424 1187601 : (struct extent_inode_elem *)(uintptr_t)node->aux : NULL;
425 :
426 : /* additional parents require new refs being added here */
427 2375203 : while ((node = ulist_next(parents, &uiter))) {
428 1 : new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache,
429 : GFP_NOFS);
430 1 : if (!new_ref) {
431 : ret = -ENOMEM;
432 : goto out;
433 : }
434 1 : memcpy(new_ref, ref, sizeof(*ref));
435 1 : new_ref->parent = node->val;
436 1 : new_ref->inode_list = (struct extent_inode_elem *)
437 1 : (uintptr_t)node->aux;
438 1 : list_add(&new_ref->list, &ref->list);
439 : }
440 1187601 : ulist_reinit(parents);
441 : }
442 : out:
443 646103 : ulist_free(parents);
444 646103 : return ret;
445 : }
446 :
447 13497596 : static inline int ref_for_same_block(struct __prelim_ref *ref1,
448 : struct __prelim_ref *ref2)
449 : {
450 13497596 : if (ref1->level != ref2->level)
451 : return 0;
452 13497596 : if (ref1->root_id != ref2->root_id)
453 : return 0;
454 110717 : if (ref1->key_for_search.type != ref2->key_for_search.type)
455 : return 0;
456 110569 : if (ref1->key_for_search.objectid != ref2->key_for_search.objectid)
457 : return 0;
458 110545 : if (ref1->key_for_search.offset != ref2->key_for_search.offset)
459 : return 0;
460 110545 : if (ref1->parent != ref2->parent)
461 : return 0;
462 :
463 422 : return 1;
464 : }
465 :
466 : /*
467 : * read tree blocks and add keys where required.
468 : */
469 646103 : static int __add_missing_keys(struct btrfs_fs_info *fs_info,
470 : struct list_head *head)
471 : {
472 : struct list_head *pos;
473 1161215 : struct extent_buffer *eb;
474 :
475 1843501 : list_for_each(pos, head) {
476 : struct __prelim_ref *ref;
477 : ref = list_entry(pos, struct __prelim_ref, list);
478 :
479 1197398 : if (ref->parent)
480 8953 : continue;
481 1188445 : if (ref->key_for_search.type)
482 27230 : continue;
483 1161215 : BUG_ON(!ref->wanted_disk_byte);
484 1161215 : eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte,
485 1161215 : fs_info->tree_root->leafsize, 0);
486 1161215 : if (!eb || !extent_buffer_uptodate(eb)) {
487 0 : free_extent_buffer(eb);
488 : return -EIO;
489 : }
490 1161215 : btrfs_tree_read_lock(eb);
491 1161215 : if (btrfs_header_level(eb) == 0)
492 578775 : btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0);
493 : else
494 : btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0);
495 1161215 : btrfs_tree_read_unlock(eb);
496 1161215 : free_extent_buffer(eb);
497 : }
498 : return 0;
499 : }
500 :
501 : /*
502 : * merge two lists of backrefs and adjust counts accordingly
503 : *
504 : * mode = 1: merge identical keys, if key is set
505 : * FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
506 : * additionally, we could even add a key range for the blocks we
507 : * looked into to merge even more (-> replace unresolved refs by those
508 : * having a parent).
509 : * mode = 2: merge identical parents
510 : */
511 1292206 : static void __merge_refs(struct list_head *head, int mode)
512 : {
513 : struct list_head *pos1;
514 :
515 3686112 : list_for_each(pos1, head) {
516 : struct list_head *n2;
517 : struct list_head *pos2;
518 : struct __prelim_ref *ref1;
519 :
520 : ref1 = list_entry(pos1, struct __prelim_ref, list);
521 :
522 31782574 : for (pos2 = pos1->next, n2 = pos2->next; pos2 != head;
523 26994762 : pos2 = n2, n2 = pos2->next) {
524 : struct __prelim_ref *ref2;
525 : struct __prelim_ref *xchg;
526 : struct extent_inode_elem *eie;
527 :
528 : ref2 = list_entry(pos2, struct __prelim_ref, list);
529 :
530 26994762 : if (mode == 1) {
531 13497596 : if (!ref_for_same_block(ref1, ref2))
532 13497174 : continue;
533 422 : if (!ref1->parent && ref2->parent) {
534 : xchg = ref1;
535 : ref1 = ref2;
536 : ref2 = xchg;
537 : }
538 : } else {
539 13497166 : if (ref1->parent != ref2->parent)
540 13497119 : continue;
541 : }
542 :
543 469 : eie = ref1->inode_list;
544 469 : while (eie && eie->next)
545 : eie = eie->next;
546 469 : if (eie)
547 16 : eie->next = ref2->inode_list;
548 : else
549 453 : ref1->inode_list = ref2->inode_list;
550 469 : ref1->count += ref2->count;
551 :
552 469 : list_del(&ref2->list);
553 469 : kmem_cache_free(btrfs_prelim_ref_cache, ref2);
554 : }
555 :
556 : }
557 1292206 : }
558 :
559 : /*
560 : * add all currently queued delayed refs from this head whose seq nr is
561 : * smaller or equal that seq to the list
562 : */
563 1673 : static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
564 : struct list_head *prefs, u64 *total_refs)
565 : {
566 1673 : struct btrfs_delayed_extent_op *extent_op = head->extent_op;
567 : struct rb_node *n = &head->node.rb_node;
568 : struct btrfs_key key;
569 1673 : struct btrfs_key op_key = {0};
570 : int sgn;
571 : int ret = 0;
572 :
573 1673 : if (extent_op && extent_op->update_key)
574 : btrfs_disk_key_to_cpu(&op_key, &extent_op->key);
575 :
576 : spin_lock(&head->lock);
577 1673 : n = rb_first(&head->ref_root);
578 5197 : while (n) {
579 : struct btrfs_delayed_ref_node *node;
580 : node = rb_entry(n, struct btrfs_delayed_ref_node,
581 : rb_node);
582 1851 : n = rb_next(n);
583 1851 : if (node->seq > seq)
584 1 : continue;
585 :
586 1850 : switch (node->action) {
587 : case BTRFS_ADD_DELAYED_EXTENT:
588 : case BTRFS_UPDATE_DELAYED_HEAD:
589 0 : WARN_ON(1);
590 0 : continue;
591 : case BTRFS_ADD_DELAYED_REF:
592 : sgn = 1;
593 : break;
594 : case BTRFS_DROP_DELAYED_REF:
595 : sgn = -1;
596 452 : break;
597 : default:
598 0 : BUG_ON(1);
599 : }
600 1850 : *total_refs += (node->ref_mod * sgn);
601 1850 : switch (node->type) {
602 : case BTRFS_TREE_BLOCK_REF_KEY: {
603 : struct btrfs_delayed_tree_ref *ref;
604 :
605 : ref = btrfs_delayed_node_to_tree_ref(node);
606 3328 : ret = __add_prelim_ref(prefs, ref->root, &op_key,
607 1664 : ref->level + 1, 0, node->bytenr,
608 1664 : node->ref_mod * sgn, GFP_ATOMIC);
609 1664 : break;
610 : }
611 : case BTRFS_SHARED_BLOCK_REF_KEY: {
612 : struct btrfs_delayed_tree_ref *ref;
613 :
614 : ref = btrfs_delayed_node_to_tree_ref(node);
615 356 : ret = __add_prelim_ref(prefs, ref->root, NULL,
616 178 : ref->level + 1, ref->parent,
617 : node->bytenr,
618 178 : node->ref_mod * sgn, GFP_ATOMIC);
619 178 : break;
620 : }
621 : case BTRFS_EXTENT_DATA_REF_KEY: {
622 : struct btrfs_delayed_data_ref *ref;
623 : ref = btrfs_delayed_node_to_data_ref(node);
624 :
625 8 : key.objectid = ref->objectid;
626 8 : key.type = BTRFS_EXTENT_DATA_KEY;
627 8 : key.offset = ref->offset;
628 8 : ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
629 : node->bytenr,
630 8 : node->ref_mod * sgn, GFP_ATOMIC);
631 8 : break;
632 : }
633 : case BTRFS_SHARED_DATA_REF_KEY: {
634 : struct btrfs_delayed_data_ref *ref;
635 :
636 : ref = btrfs_delayed_node_to_data_ref(node);
637 :
638 0 : key.objectid = ref->objectid;
639 0 : key.type = BTRFS_EXTENT_DATA_KEY;
640 0 : key.offset = ref->offset;
641 0 : ret = __add_prelim_ref(prefs, ref->root, &key, 0,
642 : ref->parent, node->bytenr,
643 0 : node->ref_mod * sgn, GFP_ATOMIC);
644 0 : break;
645 : }
646 : default:
647 0 : WARN_ON(1);
648 : }
649 1850 : if (ret)
650 : break;
651 : }
652 : spin_unlock(&head->lock);
653 1673 : return ret;
654 : }
655 :
656 : /*
657 : * add all inline backrefs for bytenr to the list
658 : */
659 643965 : static int __add_inline_refs(struct btrfs_fs_info *fs_info,
660 : struct btrfs_path *path, u64 bytenr,
661 : int *info_level, struct list_head *prefs,
662 : u64 *total_refs)
663 : {
664 : int ret = 0;
665 : int slot;
666 : struct extent_buffer *leaf;
667 : struct btrfs_key key;
668 : struct btrfs_key found_key;
669 : unsigned long ptr;
670 : unsigned long end;
671 : struct btrfs_extent_item *ei;
672 : u64 flags;
673 : u64 item_size;
674 :
675 : /*
676 : * enumerate all inline refs
677 : */
678 643965 : leaf = path->nodes[0];
679 643965 : slot = path->slots[0];
680 :
681 643965 : item_size = btrfs_item_size_nr(leaf, slot);
682 643965 : BUG_ON(item_size < sizeof(*ei));
683 :
684 643965 : ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
685 : flags = btrfs_extent_flags(leaf, ei);
686 1287930 : *total_refs += btrfs_extent_refs(leaf, ei);
687 643965 : btrfs_item_key_to_cpu(leaf, &found_key, slot);
688 :
689 643965 : ptr = (unsigned long)(ei + 1);
690 643965 : end = (unsigned long)ei + item_size;
691 :
692 1287930 : if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
693 643965 : flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
694 : struct btrfs_tree_block_info *info;
695 :
696 : info = (struct btrfs_tree_block_info *)ptr;
697 616904 : *info_level = btrfs_tree_block_level(leaf, info);
698 616904 : ptr += sizeof(struct btrfs_tree_block_info);
699 616904 : BUG_ON(ptr > end);
700 27061 : } else if (found_key.type == BTRFS_METADATA_ITEM_KEY) {
701 0 : *info_level = found_key.offset;
702 : } else {
703 27061 : BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
704 : }
705 :
706 1839520 : while (ptr < end) {
707 : struct btrfs_extent_inline_ref *iref;
708 : u64 offset;
709 : int type;
710 :
711 1195555 : iref = (struct btrfs_extent_inline_ref *)ptr;
712 1195555 : type = btrfs_extent_inline_ref_type(leaf, iref);
713 : offset = btrfs_extent_inline_ref_offset(leaf, iref);
714 :
715 1195555 : switch (type) {
716 : case BTRFS_SHARED_BLOCK_REF_KEY:
717 693 : ret = __add_prelim_ref(prefs, 0, NULL,
718 693 : *info_level + 1, offset,
719 : bytenr, 1, GFP_NOFS);
720 : break;
721 : case BTRFS_SHARED_DATA_REF_KEY: {
722 : struct btrfs_shared_data_ref *sdref;
723 : int count;
724 :
725 8082 : sdref = (struct btrfs_shared_data_ref *)(iref + 1);
726 8082 : count = btrfs_shared_data_ref_count(leaf, sdref);
727 8082 : ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
728 : bytenr, count, GFP_NOFS);
729 : break;
730 : }
731 : case BTRFS_TREE_BLOCK_REF_KEY:
732 1160770 : ret = __add_prelim_ref(prefs, offset, NULL,
733 1160770 : *info_level + 1, 0,
734 : bytenr, 1, GFP_NOFS);
735 : break;
736 : case BTRFS_EXTENT_DATA_REF_KEY: {
737 : struct btrfs_extent_data_ref *dref;
738 : int count;
739 : u64 root;
740 :
741 26010 : dref = (struct btrfs_extent_data_ref *)(&iref->offset);
742 26010 : count = btrfs_extent_data_ref_count(leaf, dref);
743 26010 : key.objectid = btrfs_extent_data_ref_objectid(leaf,
744 : dref);
745 26010 : key.type = BTRFS_EXTENT_DATA_KEY;
746 26010 : key.offset = btrfs_extent_data_ref_offset(leaf, dref);
747 : root = btrfs_extent_data_ref_root(leaf, dref);
748 26010 : ret = __add_prelim_ref(prefs, root, &key, 0, 0,
749 : bytenr, count, GFP_NOFS);
750 : break;
751 : }
752 : default:
753 0 : WARN_ON(1);
754 : }
755 1195555 : if (ret)
756 : return ret;
757 1195555 : ptr += btrfs_extent_inline_ref_size(type);
758 : }
759 :
760 : return 0;
761 : }
762 :
763 : /*
764 : * add all non-inline backrefs for bytenr to the list
765 : */
766 643965 : static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
767 : struct btrfs_path *path, u64 bytenr,
768 : int info_level, struct list_head *prefs)
769 : {
770 643965 : struct btrfs_root *extent_root = fs_info->extent_root;
771 : int ret;
772 : int slot;
773 : struct extent_buffer *leaf;
774 : struct btrfs_key key;
775 :
776 : while (1) {
777 : ret = btrfs_next_item(extent_root, path);
778 643965 : if (ret < 0)
779 : break;
780 643965 : if (ret) {
781 : ret = 0;
782 : break;
783 : }
784 :
785 643506 : slot = path->slots[0];
786 643506 : leaf = path->nodes[0];
787 643506 : btrfs_item_key_to_cpu(leaf, &key, slot);
788 :
789 643506 : if (key.objectid != bytenr)
790 : break;
791 4124 : if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
792 0 : continue;
793 4124 : if (key.type > BTRFS_SHARED_DATA_REF_KEY)
794 : break;
795 :
796 0 : switch (key.type) {
797 : case BTRFS_SHARED_BLOCK_REF_KEY:
798 0 : ret = __add_prelim_ref(prefs, 0, NULL,
799 : info_level + 1, key.offset,
800 : bytenr, 1, GFP_NOFS);
801 : break;
802 : case BTRFS_SHARED_DATA_REF_KEY: {
803 : struct btrfs_shared_data_ref *sdref;
804 : int count;
805 :
806 0 : sdref = btrfs_item_ptr(leaf, slot,
807 : struct btrfs_shared_data_ref);
808 0 : count = btrfs_shared_data_ref_count(leaf, sdref);
809 0 : ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
810 : bytenr, count, GFP_NOFS);
811 : break;
812 : }
813 : case BTRFS_TREE_BLOCK_REF_KEY:
814 0 : ret = __add_prelim_ref(prefs, key.offset, NULL,
815 : info_level + 1, 0,
816 : bytenr, 1, GFP_NOFS);
817 : break;
818 : case BTRFS_EXTENT_DATA_REF_KEY: {
819 : struct btrfs_extent_data_ref *dref;
820 : int count;
821 : u64 root;
822 :
823 0 : dref = btrfs_item_ptr(leaf, slot,
824 : struct btrfs_extent_data_ref);
825 0 : count = btrfs_extent_data_ref_count(leaf, dref);
826 0 : key.objectid = btrfs_extent_data_ref_objectid(leaf,
827 : dref);
828 0 : key.type = BTRFS_EXTENT_DATA_KEY;
829 0 : key.offset = btrfs_extent_data_ref_offset(leaf, dref);
830 : root = btrfs_extent_data_ref_root(leaf, dref);
831 0 : ret = __add_prelim_ref(prefs, root, &key, 0, 0,
832 : bytenr, count, GFP_NOFS);
833 : break;
834 : }
835 : default:
836 0 : WARN_ON(1);
837 : }
838 0 : if (ret)
839 : return ret;
840 :
841 : }
842 :
843 : return ret;
844 : }
845 :
846 : /*
847 : * this adds all existing backrefs (inline backrefs, backrefs and delayed
848 : * refs) for the given bytenr to the refs list, merges duplicates and resolves
849 : * indirect refs to their parent bytenr.
850 : * When roots are found, they're added to the roots list
851 : *
852 : * FIXME some caching might speed things up
853 : */
854 646103 : static int find_parent_nodes(struct btrfs_trans_handle *trans,
855 1290068 : struct btrfs_fs_info *fs_info, u64 bytenr,
856 : u64 time_seq, struct ulist *refs,
857 : struct ulist *roots, const u64 *extent_item_pos)
858 : {
859 : struct btrfs_key key;
860 643965 : struct btrfs_path *path;
861 : struct btrfs_delayed_ref_root *delayed_refs = NULL;
862 : struct btrfs_delayed_ref_head *head;
863 646103 : int info_level = 0;
864 : int ret;
865 : struct list_head prefs_delayed;
866 : struct list_head prefs;
867 : struct __prelim_ref *ref;
868 646103 : struct extent_inode_elem *eie = NULL;
869 646103 : u64 total_refs = 0;
870 :
871 : INIT_LIST_HEAD(&prefs);
872 : INIT_LIST_HEAD(&prefs_delayed);
873 :
874 646103 : key.objectid = bytenr;
875 646103 : key.offset = (u64)-1;
876 646103 : if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
877 0 : key.type = BTRFS_METADATA_ITEM_KEY;
878 : else
879 646103 : key.type = BTRFS_EXTENT_ITEM_KEY;
880 :
881 646103 : path = btrfs_alloc_path();
882 646103 : if (!path)
883 : return -ENOMEM;
884 646103 : if (!trans) {
885 631206 : path->search_commit_root = 1;
886 631206 : path->skip_locking = 1;
887 : }
888 :
889 : /*
890 : * grab both a lock on the path and a lock on the delayed ref head.
891 : * We need both to get a consistent picture of how the refs look
892 : * at a specified point in time
893 : */
894 : again:
895 : head = NULL;
896 :
897 652791 : ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
898 646103 : if (ret < 0)
899 : goto out;
900 646103 : BUG_ON(ret == 0);
901 :
902 : #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
903 : if (trans && likely(trans->type != __TRANS_DUMMY)) {
904 : #else
905 646103 : if (trans) {
906 : #endif
907 : /*
908 : * look if there are updates for this ref queued and lock the
909 : * head
910 : */
911 14897 : delayed_refs = &trans->transaction->delayed_refs;
912 : spin_lock(&delayed_refs->lock);
913 14897 : head = btrfs_find_delayed_ref_head(trans, bytenr);
914 14897 : if (head) {
915 1673 : if (!mutex_trylock(&head->mutex)) {
916 0 : atomic_inc(&head->node.refs);
917 : spin_unlock(&delayed_refs->lock);
918 :
919 0 : btrfs_release_path(path);
920 :
921 : /*
922 : * Mutex was contended, block until it's
923 : * released and try again
924 : */
925 0 : mutex_lock(&head->mutex);
926 0 : mutex_unlock(&head->mutex);
927 0 : btrfs_put_delayed_ref(&head->node);
928 0 : goto again;
929 : }
930 : spin_unlock(&delayed_refs->lock);
931 1673 : ret = __add_delayed_refs(head, time_seq,
932 : &prefs_delayed, &total_refs);
933 1673 : mutex_unlock(&head->mutex);
934 1673 : if (ret)
935 : goto out;
936 : } else {
937 : spin_unlock(&delayed_refs->lock);
938 : }
939 : }
940 :
941 646103 : if (path->slots[0]) {
942 : struct extent_buffer *leaf;
943 : int slot;
944 :
945 646103 : path->slots[0]--;
946 646103 : leaf = path->nodes[0];
947 : slot = path->slots[0];
948 646103 : btrfs_item_key_to_cpu(leaf, &key, slot);
949 1290068 : if (key.objectid == bytenr &&
950 643965 : (key.type == BTRFS_EXTENT_ITEM_KEY ||
951 : key.type == BTRFS_METADATA_ITEM_KEY)) {
952 643965 : ret = __add_inline_refs(fs_info, path, bytenr,
953 : &info_level, &prefs,
954 : &total_refs);
955 643965 : if (ret)
956 : goto out;
957 1287930 : ret = __add_keyed_refs(fs_info, path, bytenr,
958 : info_level, &prefs);
959 643965 : if (ret)
960 : goto out;
961 : }
962 : }
963 646103 : btrfs_release_path(path);
964 :
965 : list_splice_init(&prefs_delayed, &prefs);
966 :
967 646103 : ret = __add_missing_keys(fs_info, &prefs);
968 646103 : if (ret)
969 : goto out;
970 :
971 646103 : __merge_refs(&prefs, 1);
972 :
973 646103 : ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs,
974 : extent_item_pos, total_refs);
975 646103 : if (ret)
976 : goto out;
977 :
978 646103 : __merge_refs(&prefs, 2);
979 :
980 2489136 : while (!list_empty(&prefs)) {
981 : ref = list_first_entry(&prefs, struct __prelim_ref, list);
982 1196930 : WARN_ON(ref->count < 0);
983 1196930 : if (roots && ref->count && ref->root_id && ref->parent == 0) {
984 : /* no parent == root of tree */
985 579479 : ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
986 579479 : if (ret < 0)
987 : goto out;
988 : }
989 1196930 : if (ref->count && ref->parent) {
990 623685 : if (extent_item_pos && !ref->inode_list &&
991 6688 : ref->level == 0) {
992 : u32 bsz;
993 : struct extent_buffer *eb;
994 6688 : bsz = btrfs_level_size(fs_info->extent_root,
995 : ref->level);
996 6688 : eb = read_tree_block(fs_info->extent_root,
997 : ref->parent, bsz, 0);
998 6688 : if (!eb || !extent_buffer_uptodate(eb)) {
999 0 : free_extent_buffer(eb);
1000 : ret = -EIO;
1001 0 : goto out;
1002 : }
1003 6688 : btrfs_tree_read_lock(eb);
1004 6688 : btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1005 6688 : ret = find_extent_in_eb(eb, bytenr,
1006 : *extent_item_pos, &eie);
1007 6688 : btrfs_tree_read_unlock_blocking(eb);
1008 6688 : free_extent_buffer(eb);
1009 6688 : if (ret < 0)
1010 : goto out;
1011 6688 : ref->inode_list = eie;
1012 : }
1013 616997 : ret = ulist_add_merge_ptr(refs, ref->parent,
1014 616997 : ref->inode_list,
1015 : (void **)&eie, GFP_NOFS);
1016 616997 : if (ret < 0)
1017 : goto out;
1018 616997 : if (!ret && extent_item_pos) {
1019 : /*
1020 : * we've recorded that parent, so we must extend
1021 : * its inode list here
1022 : */
1023 0 : BUG_ON(!eie);
1024 0 : while (eie->next)
1025 0 : eie = eie->next;
1026 0 : eie->next = ref->inode_list;
1027 : }
1028 616997 : eie = NULL;
1029 : }
1030 1196930 : list_del(&ref->list);
1031 1196930 : kmem_cache_free(btrfs_prelim_ref_cache, ref);
1032 : }
1033 :
1034 : out:
1035 646103 : btrfs_free_path(path);
1036 1292206 : while (!list_empty(&prefs)) {
1037 : ref = list_first_entry(&prefs, struct __prelim_ref, list);
1038 0 : list_del(&ref->list);
1039 0 : kmem_cache_free(btrfs_prelim_ref_cache, ref);
1040 : }
1041 646103 : while (!list_empty(&prefs_delayed)) {
1042 : ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
1043 : list);
1044 0 : list_del(&ref->list);
1045 0 : kmem_cache_free(btrfs_prelim_ref_cache, ref);
1046 : }
1047 646103 : if (ret < 0)
1048 0 : free_inode_elem_list(eie);
1049 646103 : return ret;
1050 : }
1051 :
1052 23663 : static void free_leaf_list(struct ulist *blocks)
1053 : {
1054 : struct ulist_node *node = NULL;
1055 : struct extent_inode_elem *eie;
1056 : struct ulist_iterator uiter;
1057 :
1058 23663 : ULIST_ITER_INIT(&uiter);
1059 77974 : while ((node = ulist_next(blocks, &uiter))) {
1060 30648 : if (!node->aux)
1061 1 : continue;
1062 30647 : eie = (struct extent_inode_elem *)(uintptr_t)node->aux;
1063 : free_inode_elem_list(eie);
1064 30647 : node->aux = 0;
1065 : }
1066 :
1067 23663 : ulist_free(blocks);
1068 23663 : }
1069 :
1070 : /*
1071 : * Finds all leafs with a reference to the specified combination of bytenr and
1072 : * offset. key_list_head will point to a list of corresponding keys (caller must
1073 : * free each list element). The leafs will be stored in the leafs ulist, which
1074 : * must be freed with ulist_free.
1075 : *
1076 : * returns 0 on success, <0 on error
1077 : */
1078 23663 : static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
1079 : struct btrfs_fs_info *fs_info, u64 bytenr,
1080 : u64 time_seq, struct ulist **leafs,
1081 : const u64 *extent_item_pos)
1082 : {
1083 : int ret;
1084 :
1085 23663 : *leafs = ulist_alloc(GFP_NOFS);
1086 23663 : if (!*leafs)
1087 : return -ENOMEM;
1088 :
1089 23663 : ret = find_parent_nodes(trans, fs_info, bytenr,
1090 : time_seq, *leafs, NULL, extent_item_pos);
1091 23663 : if (ret < 0 && ret != -ENOENT) {
1092 0 : free_leaf_list(*leafs);
1093 0 : return ret;
1094 : }
1095 :
1096 : return 0;
1097 : }
1098 :
1099 : /*
1100 : * walk all backrefs for a given extent to find all roots that reference this
1101 : * extent. Walking a backref means finding all extents that reference this
1102 : * extent and in turn walk the backrefs of those, too. Naturally this is a
1103 : * recursive process, but here it is implemented in an iterative fashion: We
1104 : * find all referencing extents for the extent in question and put them on a
1105 : * list. In turn, we find all referencing extents for those, further appending
1106 : * to the list. The way we iterate the list allows adding more elements after
1107 : * the current while iterating. The process stops when we reach the end of the
1108 : * list. Found roots are added to the roots list.
1109 : *
1110 : * returns 0 on success, < 0 on error.
1111 : */
1112 36092 : static int __btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1113 : struct btrfs_fs_info *fs_info, u64 bytenr,
1114 : u64 time_seq, struct ulist **roots)
1115 : {
1116 : struct ulist *tmp;
1117 : struct ulist_node *node = NULL;
1118 : struct ulist_iterator uiter;
1119 : int ret;
1120 :
1121 36092 : tmp = ulist_alloc(GFP_NOFS);
1122 36092 : if (!tmp)
1123 : return -ENOMEM;
1124 36092 : *roots = ulist_alloc(GFP_NOFS);
1125 36092 : if (!*roots) {
1126 0 : ulist_free(tmp);
1127 0 : return -ENOMEM;
1128 : }
1129 :
1130 36092 : ULIST_ITER_INIT(&uiter);
1131 : while (1) {
1132 622440 : ret = find_parent_nodes(trans, fs_info, bytenr,
1133 : time_seq, tmp, *roots, NULL);
1134 622440 : if (ret < 0 && ret != -ENOENT) {
1135 0 : ulist_free(tmp);
1136 0 : ulist_free(*roots);
1137 0 : return ret;
1138 : }
1139 622440 : node = ulist_next(tmp, &uiter);
1140 622440 : if (!node)
1141 : break;
1142 586348 : bytenr = node->val;
1143 586348 : cond_resched();
1144 586348 : }
1145 :
1146 36092 : ulist_free(tmp);
1147 36092 : return 0;
1148 : }
1149 :
1150 5444 : int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
1151 : struct btrfs_fs_info *fs_info, u64 bytenr,
1152 : u64 time_seq, struct ulist **roots)
1153 : {
1154 : int ret;
1155 :
1156 5444 : if (!trans)
1157 2694 : down_read(&fs_info->commit_root_sem);
1158 5444 : ret = __btrfs_find_all_roots(trans, fs_info, bytenr, time_seq, roots);
1159 5444 : if (!trans)
1160 2694 : up_read(&fs_info->commit_root_sem);
1161 5444 : return ret;
1162 : }
1163 :
1164 : /*
1165 : * this makes the path point to (inum INODE_ITEM ioff)
1166 : */
1167 0 : int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
1168 : struct btrfs_path *path)
1169 : {
1170 : struct btrfs_key key;
1171 0 : return btrfs_find_item(fs_root, path, inum, ioff,
1172 : BTRFS_INODE_ITEM_KEY, &key);
1173 : }
1174 :
1175 : static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
1176 : struct btrfs_path *path,
1177 : struct btrfs_key *found_key)
1178 : {
1179 5231 : return btrfs_find_item(fs_root, path, inum, ioff,
1180 : BTRFS_INODE_REF_KEY, found_key);
1181 : }
1182 :
1183 463 : int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid,
1184 : u64 start_off, struct btrfs_path *path,
1185 : struct btrfs_inode_extref **ret_extref,
1186 : u64 *found_off)
1187 : {
1188 : int ret, slot;
1189 : struct btrfs_key key;
1190 : struct btrfs_key found_key;
1191 : struct btrfs_inode_extref *extref;
1192 470 : struct extent_buffer *leaf;
1193 : unsigned long ptr;
1194 :
1195 463 : key.objectid = inode_objectid;
1196 : btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY);
1197 463 : key.offset = start_off;
1198 :
1199 463 : ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1200 463 : if (ret < 0)
1201 : return ret;
1202 :
1203 : while (1) {
1204 470 : leaf = path->nodes[0];
1205 470 : slot = path->slots[0];
1206 940 : if (slot >= btrfs_header_nritems(leaf)) {
1207 : /*
1208 : * If the item at offset is not found,
1209 : * btrfs_search_slot will point us to the slot
1210 : * where it should be inserted. In our case
1211 : * that will be the slot directly before the
1212 : * next INODE_REF_KEY_V2 item. In the case
1213 : * that we're pointing to the last slot in a
1214 : * leaf, we must move one leaf over.
1215 : */
1216 7 : ret = btrfs_next_leaf(root, path);
1217 7 : if (ret) {
1218 0 : if (ret >= 1)
1219 : ret = -ENOENT;
1220 : break;
1221 : }
1222 7 : continue;
1223 : }
1224 :
1225 463 : btrfs_item_key_to_cpu(leaf, &found_key, slot);
1226 :
1227 : /*
1228 : * Check that we're still looking at an extended ref key for
1229 : * this particular objectid. If we have different
1230 : * objectid or type then there are no more to be found
1231 : * in the tree and we can exit.
1232 : */
1233 : ret = -ENOENT;
1234 463 : if (found_key.objectid != inode_objectid)
1235 : break;
1236 463 : if (btrfs_key_type(&found_key) != BTRFS_INODE_EXTREF_KEY)
1237 : break;
1238 :
1239 : ret = 0;
1240 0 : ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
1241 0 : extref = (struct btrfs_inode_extref *)ptr;
1242 0 : *ret_extref = extref;
1243 0 : if (found_off)
1244 0 : *found_off = found_key.offset;
1245 : break;
1246 7 : }
1247 :
1248 463 : return ret;
1249 : }
1250 :
1251 : /*
1252 : * this iterates to turn a name (from iref/extref) into a full filesystem path.
1253 : * Elements of the path are separated by '/' and the path is guaranteed to be
1254 : * 0-terminated. the path is only given within the current file system.
1255 : * Therefore, it never starts with a '/'. the caller is responsible to provide
1256 : * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
1257 : * the start point of the resulting string is returned. this pointer is within
1258 : * dest, normally.
1259 : * in case the path buffer would overflow, the pointer is decremented further
1260 : * as if output was written to the buffer, though no more output is actually
1261 : * generated. that way, the caller can determine how much space would be
1262 : * required for the path to fit into the buffer. in that case, the returned
1263 : * value will be smaller than dest. callers must check this!
1264 : */
1265 740 : char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
1266 : u32 name_len, unsigned long name_off,
1267 : struct extent_buffer *eb_in, u64 parent,
1268 : char *dest, u32 size)
1269 : {
1270 : int slot;
1271 : u64 next_inum;
1272 : int ret;
1273 740 : s64 bytes_left = ((s64)size) - 1;
1274 : struct extent_buffer *eb = eb_in;
1275 : struct btrfs_key found_key;
1276 740 : int leave_spinning = path->leave_spinning;
1277 : struct btrfs_inode_ref *iref;
1278 :
1279 740 : if (bytes_left >= 0)
1280 740 : dest[bytes_left] = '\0';
1281 :
1282 740 : path->leave_spinning = 1;
1283 : while (1) {
1284 4057 : bytes_left -= name_len;
1285 4057 : if (bytes_left >= 0)
1286 4057 : read_extent_buffer(eb, dest + bytes_left,
1287 : name_off, name_len);
1288 4057 : if (eb != eb_in) {
1289 3317 : btrfs_tree_read_unlock_blocking(eb);
1290 3317 : free_extent_buffer(eb);
1291 : }
1292 : ret = inode_ref_info(parent, 0, fs_root, path, &found_key);
1293 4057 : if (ret > 0)
1294 : ret = -ENOENT;
1295 4057 : if (ret)
1296 : break;
1297 :
1298 4057 : next_inum = found_key.offset;
1299 :
1300 : /* regular exit ahead */
1301 4057 : if (parent == next_inum)
1302 : break;
1303 :
1304 3317 : slot = path->slots[0];
1305 3317 : eb = path->nodes[0];
1306 : /* make sure we can use eb after releasing the path */
1307 3317 : if (eb != eb_in) {
1308 3317 : atomic_inc(&eb->refs);
1309 3317 : btrfs_tree_read_lock(eb);
1310 3317 : btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1311 : }
1312 3317 : btrfs_release_path(path);
1313 3317 : iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1314 :
1315 3317 : name_len = btrfs_inode_ref_name_len(eb, iref);
1316 3317 : name_off = (unsigned long)(iref + 1);
1317 :
1318 : parent = next_inum;
1319 3317 : --bytes_left;
1320 3317 : if (bytes_left >= 0)
1321 3317 : dest[bytes_left] = '/';
1322 : }
1323 :
1324 740 : btrfs_release_path(path);
1325 740 : path->leave_spinning = leave_spinning;
1326 :
1327 740 : if (ret)
1328 0 : return ERR_PTR(ret);
1329 :
1330 740 : return dest + bytes_left;
1331 : }
1332 :
1333 : /*
1334 : * this makes the path point to (logical EXTENT_ITEM *)
1335 : * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
1336 : * tree blocks and <0 on error.
1337 : */
1338 23803 : int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
1339 : struct btrfs_path *path, struct btrfs_key *found_key,
1340 : u64 *flags_ret)
1341 : {
1342 : int ret;
1343 : u64 flags;
1344 : u64 size = 0;
1345 : u32 item_size;
1346 : struct extent_buffer *eb;
1347 : struct btrfs_extent_item *ei;
1348 : struct btrfs_key key;
1349 :
1350 23803 : if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1351 0 : key.type = BTRFS_METADATA_ITEM_KEY;
1352 : else
1353 23803 : key.type = BTRFS_EXTENT_ITEM_KEY;
1354 23803 : key.objectid = logical;
1355 23803 : key.offset = (u64)-1;
1356 :
1357 23803 : ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
1358 23804 : if (ret < 0)
1359 : return ret;
1360 :
1361 23804 : ret = btrfs_previous_extent_item(fs_info->extent_root, path, 0);
1362 23804 : if (ret) {
1363 0 : if (ret > 0)
1364 : ret = -ENOENT;
1365 0 : return ret;
1366 : }
1367 23804 : btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
1368 23804 : if (found_key->type == BTRFS_METADATA_ITEM_KEY)
1369 0 : size = fs_info->extent_root->leafsize;
1370 23804 : else if (found_key->type == BTRFS_EXTENT_ITEM_KEY)
1371 23803 : size = found_key->offset;
1372 :
1373 47608 : if (found_key->objectid > logical ||
1374 23804 : found_key->objectid + size <= logical) {
1375 141 : pr_debug("logical %llu is not within any extent\n", logical);
1376 : return -ENOENT;
1377 : }
1378 :
1379 23663 : eb = path->nodes[0];
1380 23663 : item_size = btrfs_item_size_nr(eb, path->slots[0]);
1381 23663 : BUG_ON(item_size < sizeof(*ei));
1382 :
1383 47326 : ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
1384 : flags = btrfs_extent_flags(eb, ei);
1385 :
1386 23663 : pr_debug("logical %llu is at position %llu within the extent (%llu "
1387 : "EXTENT_ITEM %llu) flags %#llx size %u\n",
1388 : logical, logical - found_key->objectid, found_key->objectid,
1389 : found_key->offset, flags, item_size);
1390 :
1391 23663 : WARN_ON(!flags_ret);
1392 23663 : if (flags_ret) {
1393 23663 : if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1394 0 : *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
1395 23663 : else if (flags & BTRFS_EXTENT_FLAG_DATA)
1396 23663 : *flags_ret = BTRFS_EXTENT_FLAG_DATA;
1397 : else
1398 0 : BUG_ON(1);
1399 : return 0;
1400 : }
1401 :
1402 : return -EIO;
1403 : }
1404 :
1405 : /*
1406 : * helper function to iterate extent inline refs. ptr must point to a 0 value
1407 : * for the first call and may be modified. it is used to track state.
1408 : * if more refs exist, 0 is returned and the next call to
1409 : * __get_extent_inline_ref must pass the modified ptr parameter to get the
1410 : * next ref. after the last ref was processed, 1 is returned.
1411 : * returns <0 on error
1412 : */
1413 0 : static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
1414 : struct btrfs_key *key,
1415 : struct btrfs_extent_item *ei, u32 item_size,
1416 : struct btrfs_extent_inline_ref **out_eiref,
1417 : int *out_type)
1418 : {
1419 : unsigned long end;
1420 : u64 flags;
1421 : struct btrfs_tree_block_info *info;
1422 :
1423 0 : if (!*ptr) {
1424 : /* first call */
1425 : flags = btrfs_extent_flags(eb, ei);
1426 0 : if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1427 0 : if (key->type == BTRFS_METADATA_ITEM_KEY) {
1428 : /* a skinny metadata extent */
1429 0 : *out_eiref =
1430 0 : (struct btrfs_extent_inline_ref *)(ei + 1);
1431 : } else {
1432 0 : WARN_ON(key->type != BTRFS_EXTENT_ITEM_KEY);
1433 : info = (struct btrfs_tree_block_info *)(ei + 1);
1434 0 : *out_eiref =
1435 0 : (struct btrfs_extent_inline_ref *)(info + 1);
1436 : }
1437 : } else {
1438 0 : *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
1439 : }
1440 0 : *ptr = (unsigned long)*out_eiref;
1441 0 : if ((unsigned long)(*ptr) >= (unsigned long)ei + item_size)
1442 : return -ENOENT;
1443 : }
1444 :
1445 0 : end = (unsigned long)ei + item_size;
1446 0 : *out_eiref = (struct btrfs_extent_inline_ref *)(*ptr);
1447 0 : *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
1448 :
1449 0 : *ptr += btrfs_extent_inline_ref_size(*out_type);
1450 0 : WARN_ON(*ptr > end);
1451 0 : if (*ptr == end)
1452 : return 1; /* last */
1453 :
1454 : return 0;
1455 : }
1456 :
1457 : /*
1458 : * reads the tree block backref for an extent. tree level and root are returned
1459 : * through out_level and out_root. ptr must point to a 0 value for the first
1460 : * call and may be modified (see __get_extent_inline_ref comment).
1461 : * returns 0 if data was provided, 1 if there was no more data to provide or
1462 : * <0 on error.
1463 : */
1464 0 : int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
1465 : struct btrfs_key *key, struct btrfs_extent_item *ei,
1466 : u32 item_size, u64 *out_root, u8 *out_level)
1467 : {
1468 : int ret;
1469 : int type;
1470 : struct btrfs_tree_block_info *info;
1471 : struct btrfs_extent_inline_ref *eiref;
1472 :
1473 0 : if (*ptr == (unsigned long)-1)
1474 : return 1;
1475 :
1476 : while (1) {
1477 0 : ret = __get_extent_inline_ref(ptr, eb, key, ei, item_size,
1478 : &eiref, &type);
1479 0 : if (ret < 0)
1480 : return ret;
1481 :
1482 0 : if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1483 : type == BTRFS_SHARED_BLOCK_REF_KEY)
1484 : break;
1485 :
1486 0 : if (ret == 1)
1487 : return 1;
1488 : }
1489 :
1490 : /* we can treat both ref types equally here */
1491 0 : info = (struct btrfs_tree_block_info *)(ei + 1);
1492 0 : *out_root = btrfs_extent_inline_ref_offset(eb, eiref);
1493 0 : *out_level = btrfs_tree_block_level(eb, info);
1494 :
1495 0 : if (ret == 1)
1496 0 : *ptr = (unsigned long)-1;
1497 :
1498 : return 0;
1499 : }
1500 :
1501 573901 : static int iterate_leaf_refs(struct extent_inode_elem *inode_list,
1502 : u64 root, u64 extent_item_objectid,
1503 : iterate_extent_inodes_t *iterate, void *ctx)
1504 : {
1505 : struct extent_inode_elem *eie;
1506 : int ret = 0;
1507 :
1508 1147330 : for (eie = inode_list; eie; eie = eie->next) {
1509 573920 : pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1510 : "root %llu\n", extent_item_objectid,
1511 : eie->inum, eie->offset, root);
1512 573920 : ret = iterate(eie->inum, eie->offset, root, ctx);
1513 573920 : if (ret) {
1514 491 : pr_debug("stopping iteration for %llu due to ret=%d\n",
1515 : extent_item_objectid, ret);
1516 : break;
1517 : }
1518 : }
1519 :
1520 573901 : return ret;
1521 : }
1522 :
1523 : /*
1524 : * calls iterate() for every inode that references the extent identified by
1525 : * the given parameters.
1526 : * when the iterator function returns a non-zero value, iteration stops.
1527 : */
1528 23663 : int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
1529 : u64 extent_item_objectid, u64 extent_item_pos,
1530 : int search_commit_root,
1531 : iterate_extent_inodes_t *iterate, void *ctx)
1532 : {
1533 : int ret;
1534 : struct btrfs_trans_handle *trans = NULL;
1535 23663 : struct ulist *refs = NULL;
1536 23663 : struct ulist *roots = NULL;
1537 : struct ulist_node *ref_node = NULL;
1538 : struct ulist_node *root_node = NULL;
1539 23663 : struct seq_list tree_mod_seq_elem = {};
1540 : struct ulist_iterator ref_uiter;
1541 : struct ulist_iterator root_uiter;
1542 :
1543 23663 : pr_debug("resolving all inodes for extent %llu\n",
1544 : extent_item_objectid);
1545 :
1546 23663 : if (!search_commit_root) {
1547 2103 : trans = btrfs_join_transaction(fs_info->extent_root);
1548 2103 : if (IS_ERR(trans))
1549 0 : return PTR_ERR(trans);
1550 2103 : btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem);
1551 : } else {
1552 21560 : down_read(&fs_info->commit_root_sem);
1553 : }
1554 :
1555 23663 : ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
1556 : tree_mod_seq_elem.seq, &refs,
1557 : &extent_item_pos);
1558 23663 : if (ret)
1559 : goto out;
1560 :
1561 23663 : ULIST_ITER_INIT(&ref_uiter);
1562 77974 : while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) {
1563 30648 : ret = __btrfs_find_all_roots(trans, fs_info, ref_node->val,
1564 : tree_mod_seq_elem.seq, &roots);
1565 30648 : if (ret)
1566 : break;
1567 30648 : ULIST_ITER_INIT(&root_uiter);
1568 635197 : while (!ret && (root_node = ulist_next(roots, &root_uiter))) {
1569 573901 : pr_debug("root %llu references leaf %llu, data list "
1570 : "%#llx\n", root_node->val, ref_node->val,
1571 : ref_node->aux);
1572 1147802 : ret = iterate_leaf_refs((struct extent_inode_elem *)
1573 573901 : (uintptr_t)ref_node->aux,
1574 : root_node->val,
1575 : extent_item_objectid,
1576 : iterate, ctx);
1577 : }
1578 30648 : ulist_free(roots);
1579 : }
1580 :
1581 23663 : free_leaf_list(refs);
1582 : out:
1583 23663 : if (!search_commit_root) {
1584 2103 : btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem);
1585 2103 : btrfs_end_transaction(trans, fs_info->extent_root);
1586 : } else {
1587 21560 : up_read(&fs_info->commit_root_sem);
1588 : }
1589 :
1590 23663 : return ret;
1591 : }
1592 :
1593 2243 : int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
1594 : struct btrfs_path *path,
1595 : iterate_extent_inodes_t *iterate, void *ctx)
1596 : {
1597 : int ret;
1598 : u64 extent_item_pos;
1599 2243 : u64 flags = 0;
1600 : struct btrfs_key found_key;
1601 2243 : int search_commit_root = path->search_commit_root;
1602 :
1603 2243 : ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
1604 2244 : btrfs_release_path(path);
1605 2244 : if (ret < 0)
1606 : return ret;
1607 2103 : if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1608 : return -EINVAL;
1609 :
1610 2103 : extent_item_pos = logical - found_key.objectid;
1611 2103 : ret = iterate_extent_inodes(fs_info, found_key.objectid,
1612 : extent_item_pos, search_commit_root,
1613 : iterate, ctx);
1614 :
1615 2103 : return ret;
1616 : }
1617 :
1618 : typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
1619 : struct extent_buffer *eb, void *ctx);
1620 :
1621 463 : static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
1622 : struct btrfs_path *path,
1623 : iterate_irefs_t *iterate, void *ctx)
1624 : {
1625 : int ret = 0;
1626 : int slot;
1627 : u32 cur;
1628 : u32 len;
1629 : u32 name_len;
1630 : u64 parent = 0;
1631 : int found = 0;
1632 : struct extent_buffer *eb;
1633 : struct btrfs_item *item;
1634 : struct btrfs_inode_ref *iref;
1635 : struct btrfs_key found_key;
1636 :
1637 1637 : while (!ret) {
1638 1174 : ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path,
1639 : &found_key);
1640 1174 : if (ret < 0)
1641 : break;
1642 1174 : if (ret) {
1643 463 : ret = found ? 0 : -ENOENT;
1644 463 : break;
1645 : }
1646 711 : ++found;
1647 :
1648 711 : parent = found_key.offset;
1649 711 : slot = path->slots[0];
1650 711 : eb = btrfs_clone_extent_buffer(path->nodes[0]);
1651 711 : if (!eb) {
1652 : ret = -ENOMEM;
1653 : break;
1654 : }
1655 : extent_buffer_get(eb);
1656 711 : btrfs_tree_read_lock(eb);
1657 711 : btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1658 711 : btrfs_release_path(path);
1659 :
1660 : item = btrfs_item_nr(slot);
1661 711 : iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1662 :
1663 2892 : for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
1664 735 : name_len = btrfs_inode_ref_name_len(eb, iref);
1665 : /* path must be released before calling iterate()! */
1666 735 : pr_debug("following ref at offset %u for inode %llu in "
1667 : "tree %llu\n", cur, found_key.objectid,
1668 : fs_root->objectid);
1669 735 : ret = iterate(parent, name_len,
1670 735 : (unsigned long)(iref + 1), eb, ctx);
1671 735 : if (ret)
1672 : break;
1673 735 : len = sizeof(*iref) + name_len;
1674 735 : iref = (struct btrfs_inode_ref *)((char *)iref + len);
1675 : }
1676 711 : btrfs_tree_read_unlock_blocking(eb);
1677 711 : free_extent_buffer(eb);
1678 : }
1679 :
1680 463 : btrfs_release_path(path);
1681 :
1682 463 : return ret;
1683 : }
1684 :
1685 463 : static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
1686 : struct btrfs_path *path,
1687 : iterate_irefs_t *iterate, void *ctx)
1688 : {
1689 : int ret;
1690 : int slot;
1691 463 : u64 offset = 0;
1692 : u64 parent;
1693 : int found = 0;
1694 : struct extent_buffer *eb;
1695 : struct btrfs_inode_extref *extref;
1696 : struct extent_buffer *leaf;
1697 : u32 item_size;
1698 : u32 cur_offset;
1699 : unsigned long ptr;
1700 :
1701 : while (1) {
1702 463 : ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref,
1703 : &offset);
1704 463 : if (ret < 0)
1705 : break;
1706 0 : if (ret) {
1707 0 : ret = found ? 0 : -ENOENT;
1708 0 : break;
1709 : }
1710 0 : ++found;
1711 :
1712 0 : slot = path->slots[0];
1713 0 : eb = btrfs_clone_extent_buffer(path->nodes[0]);
1714 0 : if (!eb) {
1715 : ret = -ENOMEM;
1716 : break;
1717 : }
1718 : extent_buffer_get(eb);
1719 :
1720 0 : btrfs_tree_read_lock(eb);
1721 0 : btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1722 0 : btrfs_release_path(path);
1723 :
1724 0 : leaf = path->nodes[0];
1725 : item_size = btrfs_item_size_nr(leaf, slot);
1726 0 : ptr = btrfs_item_ptr_offset(leaf, slot);
1727 : cur_offset = 0;
1728 :
1729 0 : while (cur_offset < item_size) {
1730 : u32 name_len;
1731 :
1732 0 : extref = (struct btrfs_inode_extref *)(ptr + cur_offset);
1733 : parent = btrfs_inode_extref_parent(eb, extref);
1734 0 : name_len = btrfs_inode_extref_name_len(eb, extref);
1735 0 : ret = iterate(parent, name_len,
1736 0 : (unsigned long)&extref->name, eb, ctx);
1737 0 : if (ret)
1738 : break;
1739 :
1740 0 : cur_offset += btrfs_inode_extref_name_len(leaf, extref);
1741 0 : cur_offset += sizeof(*extref);
1742 : }
1743 0 : btrfs_tree_read_unlock_blocking(eb);
1744 0 : free_extent_buffer(eb);
1745 :
1746 0 : offset++;
1747 0 : }
1748 :
1749 463 : btrfs_release_path(path);
1750 :
1751 463 : return ret;
1752 : }
1753 :
1754 463 : static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
1755 : struct btrfs_path *path, iterate_irefs_t *iterate,
1756 : void *ctx)
1757 : {
1758 : int ret;
1759 : int found_refs = 0;
1760 :
1761 463 : ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
1762 463 : if (!ret)
1763 : ++found_refs;
1764 0 : else if (ret != -ENOENT)
1765 : return ret;
1766 :
1767 463 : ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
1768 463 : if (ret == -ENOENT && found_refs)
1769 : return 0;
1770 :
1771 0 : return ret;
1772 : }
1773 :
1774 : /*
1775 : * returns 0 if the path could be dumped (probably truncated)
1776 : * returns <0 in case of an error
1777 : */
1778 735 : static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
1779 : struct extent_buffer *eb, void *ctx)
1780 : {
1781 : struct inode_fs_paths *ipath = ctx;
1782 : char *fspath;
1783 : char *fspath_min;
1784 735 : int i = ipath->fspath->elem_cnt;
1785 : const int s_ptr = sizeof(char *);
1786 : u32 bytes_left;
1787 :
1788 735 : bytes_left = ipath->fspath->bytes_left > s_ptr ?
1789 735 : ipath->fspath->bytes_left - s_ptr : 0;
1790 :
1791 735 : fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
1792 735 : fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
1793 : name_off, eb, inum, fspath_min, bytes_left);
1794 735 : if (IS_ERR(fspath))
1795 0 : return PTR_ERR(fspath);
1796 :
1797 735 : if (fspath > fspath_min) {
1798 735 : ipath->fspath->val[i] = (u64)(unsigned long)fspath;
1799 735 : ++ipath->fspath->elem_cnt;
1800 735 : ipath->fspath->bytes_left = fspath - fspath_min;
1801 : } else {
1802 0 : ++ipath->fspath->elem_missed;
1803 0 : ipath->fspath->bytes_missing += fspath_min - fspath;
1804 0 : ipath->fspath->bytes_left = 0;
1805 : }
1806 :
1807 : return 0;
1808 : }
1809 :
1810 : /*
1811 : * this dumps all file system paths to the inode into the ipath struct, provided
1812 : * is has been created large enough. each path is zero-terminated and accessed
1813 : * from ipath->fspath->val[i].
1814 : * when it returns, there are ipath->fspath->elem_cnt number of paths available
1815 : * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
1816 : * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1817 : * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1818 : * have been needed to return all paths.
1819 : */
1820 463 : int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
1821 : {
1822 463 : return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
1823 : inode_to_path, ipath);
1824 : }
1825 :
1826 926 : struct btrfs_data_container *init_data_container(u32 total_bytes)
1827 : {
1828 : struct btrfs_data_container *data;
1829 : size_t alloc_bytes;
1830 :
1831 926 : alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
1832 926 : data = vmalloc(alloc_bytes);
1833 926 : if (!data)
1834 : return ERR_PTR(-ENOMEM);
1835 :
1836 926 : if (total_bytes >= sizeof(*data)) {
1837 926 : data->bytes_left = total_bytes - sizeof(*data);
1838 926 : data->bytes_missing = 0;
1839 : } else {
1840 0 : data->bytes_missing = sizeof(*data) - total_bytes;
1841 0 : data->bytes_left = 0;
1842 : }
1843 :
1844 926 : data->elem_cnt = 0;
1845 926 : data->elem_missed = 0;
1846 :
1847 926 : return data;
1848 : }
1849 :
1850 : /*
1851 : * allocates space to return multiple file system paths for an inode.
1852 : * total_bytes to allocate are passed, note that space usable for actual path
1853 : * information will be total_bytes - sizeof(struct inode_fs_paths).
1854 : * the returned pointer must be freed with free_ipath() in the end.
1855 : */
1856 463 : struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
1857 : struct btrfs_path *path)
1858 : {
1859 : struct inode_fs_paths *ifp;
1860 : struct btrfs_data_container *fspath;
1861 :
1862 463 : fspath = init_data_container(total_bytes);
1863 463 : if (IS_ERR(fspath))
1864 : return (void *)fspath;
1865 :
1866 : ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
1867 463 : if (!ifp) {
1868 0 : kfree(fspath);
1869 0 : return ERR_PTR(-ENOMEM);
1870 : }
1871 :
1872 463 : ifp->btrfs_path = path;
1873 463 : ifp->fspath = fspath;
1874 463 : ifp->fs_root = fs_root;
1875 :
1876 463 : return ifp;
1877 : }
1878 :
1879 463 : void free_ipath(struct inode_fs_paths *ipath)
1880 : {
1881 463 : if (!ipath)
1882 463 : return;
1883 463 : vfree(ipath->fspath);
1884 463 : kfree(ipath);
1885 : }
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