blob: bcec06750232e6cc3de09c62648201547709222b [file] [log] [blame]
Jan Schmidta542ad12011-06-13 19:52:59 +02001/*
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"
Jan Schmidt8da6d582011-11-23 18:55:04 +010022#include "ulist.h"
23#include "transaction.h"
24#include "delayed-ref.h"
Jan Schmidtb916a592012-04-13 12:28:08 +020025#include "locking.h"
Jan Schmidta542ad12011-06-13 19:52:59 +020026
Jan Schmidt8da6d582011-11-23 18:55:04 +010027/*
28 * this structure records all encountered refs on the way up to the root
29 */
30struct __prelim_ref {
31 struct list_head list;
32 u64 root_id;
33 struct btrfs_key key;
34 int level;
35 int count;
36 u64 parent;
37 u64 wanted_disk_byte;
38};
39
40static int __add_prelim_ref(struct list_head *head, u64 root_id,
41 struct btrfs_key *key, int level, u64 parent,
42 u64 wanted_disk_byte, int count)
43{
44 struct __prelim_ref *ref;
45
46 /* in case we're adding delayed refs, we're holding the refs spinlock */
47 ref = kmalloc(sizeof(*ref), GFP_ATOMIC);
48 if (!ref)
49 return -ENOMEM;
50
51 ref->root_id = root_id;
52 if (key)
53 ref->key = *key;
54 else
55 memset(&ref->key, 0, sizeof(ref->key));
56
57 ref->level = level;
58 ref->count = count;
59 ref->parent = parent;
60 ref->wanted_disk_byte = wanted_disk_byte;
61 list_add_tail(&ref->list, head);
62
63 return 0;
64}
65
66static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
67 struct ulist *parents,
68 struct extent_buffer *eb, int level,
69 u64 wanted_objectid, u64 wanted_disk_byte)
70{
71 int ret;
72 int slot;
73 struct btrfs_file_extent_item *fi;
74 struct btrfs_key key;
75 u64 disk_byte;
76
77add_parent:
78 ret = ulist_add(parents, eb->start, 0, GFP_NOFS);
79 if (ret < 0)
80 return ret;
81
82 if (level != 0)
83 return 0;
84
85 /*
86 * if the current leaf is full with EXTENT_DATA items, we must
87 * check the next one if that holds a reference as well.
88 * ref->count cannot be used to skip this check.
89 * repeat this until we don't find any additional EXTENT_DATA items.
90 */
91 while (1) {
92 ret = btrfs_next_leaf(root, path);
93 if (ret < 0)
94 return ret;
95 if (ret)
96 return 0;
97
98 eb = path->nodes[0];
99 for (slot = 0; slot < btrfs_header_nritems(eb); ++slot) {
100 btrfs_item_key_to_cpu(eb, &key, slot);
101 if (key.objectid != wanted_objectid ||
102 key.type != BTRFS_EXTENT_DATA_KEY)
103 return 0;
104 fi = btrfs_item_ptr(eb, slot,
105 struct btrfs_file_extent_item);
106 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
107 if (disk_byte == wanted_disk_byte)
108 goto add_parent;
109 }
110 }
111
112 return 0;
113}
114
115/*
116 * resolve an indirect backref in the form (root_id, key, level)
117 * to a logical address
118 */
119static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info,
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100120 int search_commit_root,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100121 struct __prelim_ref *ref,
122 struct ulist *parents)
123{
124 struct btrfs_path *path;
125 struct btrfs_root *root;
126 struct btrfs_key root_key;
127 struct btrfs_key key = {0};
128 struct extent_buffer *eb;
129 int ret = 0;
130 int root_level;
131 int level = ref->level;
132
133 path = btrfs_alloc_path();
134 if (!path)
135 return -ENOMEM;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100136 path->search_commit_root = !!search_commit_root;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100137
138 root_key.objectid = ref->root_id;
139 root_key.type = BTRFS_ROOT_ITEM_KEY;
140 root_key.offset = (u64)-1;
141 root = btrfs_read_fs_root_no_name(fs_info, &root_key);
142 if (IS_ERR(root)) {
143 ret = PTR_ERR(root);
144 goto out;
145 }
146
147 rcu_read_lock();
148 root_level = btrfs_header_level(root->node);
149 rcu_read_unlock();
150
151 if (root_level + 1 == level)
152 goto out;
153
154 path->lowest_level = level;
155 ret = btrfs_search_slot(NULL, root, &ref->key, path, 0, 0);
156 pr_debug("search slot in root %llu (level %d, ref count %d) returned "
157 "%d for key (%llu %u %llu)\n",
158 (unsigned long long)ref->root_id, level, ref->count, ret,
159 (unsigned long long)ref->key.objectid, ref->key.type,
160 (unsigned long long)ref->key.offset);
161 if (ret < 0)
162 goto out;
163
164 eb = path->nodes[level];
165 if (!eb) {
166 WARN_ON(1);
167 ret = 1;
168 goto out;
169 }
170
171 if (level == 0) {
172 if (ret == 1 && path->slots[0] >= btrfs_header_nritems(eb)) {
173 ret = btrfs_next_leaf(root, path);
174 if (ret)
175 goto out;
176 eb = path->nodes[0];
177 }
178
179 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
180 }
181
182 /* the last two parameters will only be used for level == 0 */
183 ret = add_all_parents(root, path, parents, eb, level, key.objectid,
184 ref->wanted_disk_byte);
185out:
186 btrfs_free_path(path);
187 return ret;
188}
189
190/*
191 * resolve all indirect backrefs from the list
192 */
193static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info,
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100194 int search_commit_root,
Jan Schmidt8da6d582011-11-23 18:55:04 +0100195 struct list_head *head)
196{
197 int err;
198 int ret = 0;
199 struct __prelim_ref *ref;
200 struct __prelim_ref *ref_safe;
201 struct __prelim_ref *new_ref;
202 struct ulist *parents;
203 struct ulist_node *node;
204
205 parents = ulist_alloc(GFP_NOFS);
206 if (!parents)
207 return -ENOMEM;
208
209 /*
210 * _safe allows us to insert directly after the current item without
211 * iterating over the newly inserted items.
212 * we're also allowed to re-assign ref during iteration.
213 */
214 list_for_each_entry_safe(ref, ref_safe, head, list) {
215 if (ref->parent) /* already direct */
216 continue;
217 if (ref->count == 0)
218 continue;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100219 err = __resolve_indirect_ref(fs_info, search_commit_root,
220 ref, parents);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100221 if (err) {
222 if (ret == 0)
223 ret = err;
224 continue;
225 }
226
227 /* we put the first parent into the ref at hand */
228 node = ulist_next(parents, NULL);
229 ref->parent = node ? node->val : 0;
230
231 /* additional parents require new refs being added here */
232 while ((node = ulist_next(parents, node))) {
233 new_ref = kmalloc(sizeof(*new_ref), GFP_NOFS);
234 if (!new_ref) {
235 ret = -ENOMEM;
236 break;
237 }
238 memcpy(new_ref, ref, sizeof(*ref));
239 new_ref->parent = node->val;
240 list_add(&new_ref->list, &ref->list);
241 }
242 ulist_reinit(parents);
243 }
244
245 ulist_free(parents);
246 return ret;
247}
248
249/*
250 * merge two lists of backrefs and adjust counts accordingly
251 *
252 * mode = 1: merge identical keys, if key is set
253 * mode = 2: merge identical parents
254 */
255static int __merge_refs(struct list_head *head, int mode)
256{
257 struct list_head *pos1;
258
259 list_for_each(pos1, head) {
260 struct list_head *n2;
261 struct list_head *pos2;
262 struct __prelim_ref *ref1;
263
264 ref1 = list_entry(pos1, struct __prelim_ref, list);
265
266 if (mode == 1 && ref1->key.type == 0)
267 continue;
268 for (pos2 = pos1->next, n2 = pos2->next; pos2 != head;
269 pos2 = n2, n2 = pos2->next) {
270 struct __prelim_ref *ref2;
271
272 ref2 = list_entry(pos2, struct __prelim_ref, list);
273
274 if (mode == 1) {
275 if (memcmp(&ref1->key, &ref2->key,
276 sizeof(ref1->key)) ||
277 ref1->level != ref2->level ||
278 ref1->root_id != ref2->root_id)
279 continue;
280 ref1->count += ref2->count;
281 } else {
282 if (ref1->parent != ref2->parent)
283 continue;
284 ref1->count += ref2->count;
285 }
286 list_del(&ref2->list);
287 kfree(ref2);
288 }
289
290 }
291 return 0;
292}
293
294/*
295 * add all currently queued delayed refs from this head whose seq nr is
296 * smaller or equal that seq to the list
297 */
298static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
299 struct btrfs_key *info_key,
300 struct list_head *prefs)
301{
302 struct btrfs_delayed_extent_op *extent_op = head->extent_op;
303 struct rb_node *n = &head->node.rb_node;
304 int sgn;
Jan Schmidtb1375d62012-01-26 15:01:11 -0500305 int ret = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100306
307 if (extent_op && extent_op->update_key)
308 btrfs_disk_key_to_cpu(info_key, &extent_op->key);
309
310 while ((n = rb_prev(n))) {
311 struct btrfs_delayed_ref_node *node;
312 node = rb_entry(n, struct btrfs_delayed_ref_node,
313 rb_node);
314 if (node->bytenr != head->node.bytenr)
315 break;
316 WARN_ON(node->is_head);
317
318 if (node->seq > seq)
319 continue;
320
321 switch (node->action) {
322 case BTRFS_ADD_DELAYED_EXTENT:
323 case BTRFS_UPDATE_DELAYED_HEAD:
324 WARN_ON(1);
325 continue;
326 case BTRFS_ADD_DELAYED_REF:
327 sgn = 1;
328 break;
329 case BTRFS_DROP_DELAYED_REF:
330 sgn = -1;
331 break;
332 default:
333 BUG_ON(1);
334 }
335 switch (node->type) {
336 case BTRFS_TREE_BLOCK_REF_KEY: {
337 struct btrfs_delayed_tree_ref *ref;
338
339 ref = btrfs_delayed_node_to_tree_ref(node);
340 ret = __add_prelim_ref(prefs, ref->root, info_key,
341 ref->level + 1, 0, node->bytenr,
342 node->ref_mod * sgn);
343 break;
344 }
345 case BTRFS_SHARED_BLOCK_REF_KEY: {
346 struct btrfs_delayed_tree_ref *ref;
347
348 ref = btrfs_delayed_node_to_tree_ref(node);
349 ret = __add_prelim_ref(prefs, ref->root, info_key,
350 ref->level + 1, ref->parent,
351 node->bytenr,
352 node->ref_mod * sgn);
353 break;
354 }
355 case BTRFS_EXTENT_DATA_REF_KEY: {
356 struct btrfs_delayed_data_ref *ref;
357 struct btrfs_key key;
358
359 ref = btrfs_delayed_node_to_data_ref(node);
360
361 key.objectid = ref->objectid;
362 key.type = BTRFS_EXTENT_DATA_KEY;
363 key.offset = ref->offset;
364 ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0,
365 node->bytenr,
366 node->ref_mod * sgn);
367 break;
368 }
369 case BTRFS_SHARED_DATA_REF_KEY: {
370 struct btrfs_delayed_data_ref *ref;
371 struct btrfs_key key;
372
373 ref = btrfs_delayed_node_to_data_ref(node);
374
375 key.objectid = ref->objectid;
376 key.type = BTRFS_EXTENT_DATA_KEY;
377 key.offset = ref->offset;
378 ret = __add_prelim_ref(prefs, ref->root, &key, 0,
379 ref->parent, node->bytenr,
380 node->ref_mod * sgn);
381 break;
382 }
383 default:
384 WARN_ON(1);
385 }
386 BUG_ON(ret);
387 }
388
389 return 0;
390}
391
392/*
393 * add all inline backrefs for bytenr to the list
394 */
395static int __add_inline_refs(struct btrfs_fs_info *fs_info,
396 struct btrfs_path *path, u64 bytenr,
397 struct btrfs_key *info_key, int *info_level,
398 struct list_head *prefs)
399{
Jan Schmidtb1375d62012-01-26 15:01:11 -0500400 int ret = 0;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100401 int slot;
402 struct extent_buffer *leaf;
403 struct btrfs_key key;
404 unsigned long ptr;
405 unsigned long end;
406 struct btrfs_extent_item *ei;
407 u64 flags;
408 u64 item_size;
409
410 /*
411 * enumerate all inline refs
412 */
413 leaf = path->nodes[0];
414 slot = path->slots[0] - 1;
415
416 item_size = btrfs_item_size_nr(leaf, slot);
417 BUG_ON(item_size < sizeof(*ei));
418
419 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
420 flags = btrfs_extent_flags(leaf, ei);
421
422 ptr = (unsigned long)(ei + 1);
423 end = (unsigned long)ei + item_size;
424
425 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
426 struct btrfs_tree_block_info *info;
427 struct btrfs_disk_key disk_key;
428
429 info = (struct btrfs_tree_block_info *)ptr;
430 *info_level = btrfs_tree_block_level(leaf, info);
431 btrfs_tree_block_key(leaf, info, &disk_key);
432 btrfs_disk_key_to_cpu(info_key, &disk_key);
433 ptr += sizeof(struct btrfs_tree_block_info);
434 BUG_ON(ptr > end);
435 } else {
436 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA));
437 }
438
439 while (ptr < end) {
440 struct btrfs_extent_inline_ref *iref;
441 u64 offset;
442 int type;
443
444 iref = (struct btrfs_extent_inline_ref *)ptr;
445 type = btrfs_extent_inline_ref_type(leaf, iref);
446 offset = btrfs_extent_inline_ref_offset(leaf, iref);
447
448 switch (type) {
449 case BTRFS_SHARED_BLOCK_REF_KEY:
450 ret = __add_prelim_ref(prefs, 0, info_key,
451 *info_level + 1, offset,
452 bytenr, 1);
453 break;
454 case BTRFS_SHARED_DATA_REF_KEY: {
455 struct btrfs_shared_data_ref *sdref;
456 int count;
457
458 sdref = (struct btrfs_shared_data_ref *)(iref + 1);
459 count = btrfs_shared_data_ref_count(leaf, sdref);
460 ret = __add_prelim_ref(prefs, 0, NULL, 0, offset,
461 bytenr, count);
462 break;
463 }
464 case BTRFS_TREE_BLOCK_REF_KEY:
465 ret = __add_prelim_ref(prefs, offset, info_key,
466 *info_level + 1, 0, bytenr, 1);
467 break;
468 case BTRFS_EXTENT_DATA_REF_KEY: {
469 struct btrfs_extent_data_ref *dref;
470 int count;
471 u64 root;
472
473 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
474 count = btrfs_extent_data_ref_count(leaf, dref);
475 key.objectid = btrfs_extent_data_ref_objectid(leaf,
476 dref);
477 key.type = BTRFS_EXTENT_DATA_KEY;
478 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
479 root = btrfs_extent_data_ref_root(leaf, dref);
480 ret = __add_prelim_ref(prefs, root, &key, 0, 0, bytenr,
481 count);
482 break;
483 }
484 default:
485 WARN_ON(1);
486 }
487 BUG_ON(ret);
488 ptr += btrfs_extent_inline_ref_size(type);
489 }
490
491 return 0;
492}
493
494/*
495 * add all non-inline backrefs for bytenr to the list
496 */
497static int __add_keyed_refs(struct btrfs_fs_info *fs_info,
498 struct btrfs_path *path, u64 bytenr,
499 struct btrfs_key *info_key, int info_level,
500 struct list_head *prefs)
501{
502 struct btrfs_root *extent_root = fs_info->extent_root;
503 int ret;
504 int slot;
505 struct extent_buffer *leaf;
506 struct btrfs_key key;
507
508 while (1) {
509 ret = btrfs_next_item(extent_root, path);
510 if (ret < 0)
511 break;
512 if (ret) {
513 ret = 0;
514 break;
515 }
516
517 slot = path->slots[0];
518 leaf = path->nodes[0];
519 btrfs_item_key_to_cpu(leaf, &key, slot);
520
521 if (key.objectid != bytenr)
522 break;
523 if (key.type < BTRFS_TREE_BLOCK_REF_KEY)
524 continue;
525 if (key.type > BTRFS_SHARED_DATA_REF_KEY)
526 break;
527
528 switch (key.type) {
529 case BTRFS_SHARED_BLOCK_REF_KEY:
530 ret = __add_prelim_ref(prefs, 0, info_key,
531 info_level + 1, key.offset,
532 bytenr, 1);
533 break;
534 case BTRFS_SHARED_DATA_REF_KEY: {
535 struct btrfs_shared_data_ref *sdref;
536 int count;
537
538 sdref = btrfs_item_ptr(leaf, slot,
539 struct btrfs_shared_data_ref);
540 count = btrfs_shared_data_ref_count(leaf, sdref);
541 ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset,
542 bytenr, count);
543 break;
544 }
545 case BTRFS_TREE_BLOCK_REF_KEY:
546 ret = __add_prelim_ref(prefs, key.offset, info_key,
547 info_level + 1, 0, bytenr, 1);
548 break;
549 case BTRFS_EXTENT_DATA_REF_KEY: {
550 struct btrfs_extent_data_ref *dref;
551 int count;
552 u64 root;
553
554 dref = btrfs_item_ptr(leaf, slot,
555 struct btrfs_extent_data_ref);
556 count = btrfs_extent_data_ref_count(leaf, dref);
557 key.objectid = btrfs_extent_data_ref_objectid(leaf,
558 dref);
559 key.type = BTRFS_EXTENT_DATA_KEY;
560 key.offset = btrfs_extent_data_ref_offset(leaf, dref);
561 root = btrfs_extent_data_ref_root(leaf, dref);
562 ret = __add_prelim_ref(prefs, root, &key, 0, 0,
563 bytenr, count);
564 break;
565 }
566 default:
567 WARN_ON(1);
568 }
569 BUG_ON(ret);
570 }
571
572 return ret;
573}
574
575/*
576 * this adds all existing backrefs (inline backrefs, backrefs and delayed
577 * refs) for the given bytenr to the refs list, merges duplicates and resolves
578 * indirect refs to their parent bytenr.
579 * When roots are found, they're added to the roots list
580 *
581 * FIXME some caching might speed things up
582 */
583static int find_parent_nodes(struct btrfs_trans_handle *trans,
584 struct btrfs_fs_info *fs_info, u64 bytenr,
585 u64 seq, struct ulist *refs, struct ulist *roots)
586{
587 struct btrfs_key key;
588 struct btrfs_path *path;
589 struct btrfs_key info_key = { 0 };
590 struct btrfs_delayed_ref_root *delayed_refs = NULL;
Li Zefand3b01062012-03-03 07:41:15 -0500591 struct btrfs_delayed_ref_head *head;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100592 int info_level = 0;
593 int ret;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100594 int search_commit_root = (trans == BTRFS_BACKREF_SEARCH_COMMIT_ROOT);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100595 struct list_head prefs_delayed;
596 struct list_head prefs;
597 struct __prelim_ref *ref;
598
599 INIT_LIST_HEAD(&prefs);
600 INIT_LIST_HEAD(&prefs_delayed);
601
602 key.objectid = bytenr;
603 key.type = BTRFS_EXTENT_ITEM_KEY;
604 key.offset = (u64)-1;
605
606 path = btrfs_alloc_path();
607 if (!path)
608 return -ENOMEM;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100609 path->search_commit_root = !!search_commit_root;
Jan Schmidt8da6d582011-11-23 18:55:04 +0100610
611 /*
612 * grab both a lock on the path and a lock on the delayed ref head.
613 * We need both to get a consistent picture of how the refs look
614 * at a specified point in time
615 */
616again:
Li Zefand3b01062012-03-03 07:41:15 -0500617 head = NULL;
618
Jan Schmidt8da6d582011-11-23 18:55:04 +0100619 ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
620 if (ret < 0)
621 goto out;
622 BUG_ON(ret == 0);
623
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100624 if (trans != BTRFS_BACKREF_SEARCH_COMMIT_ROOT) {
625 /*
626 * look if there are updates for this ref queued and lock the
627 * head
628 */
629 delayed_refs = &trans->transaction->delayed_refs;
630 spin_lock(&delayed_refs->lock);
631 head = btrfs_find_delayed_ref_head(trans, bytenr);
632 if (head) {
633 if (!mutex_trylock(&head->mutex)) {
634 atomic_inc(&head->node.refs);
635 spin_unlock(&delayed_refs->lock);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100636
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100637 btrfs_release_path(path);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100638
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100639 /*
640 * Mutex was contended, block until it's
641 * released and try again
642 */
643 mutex_lock(&head->mutex);
644 mutex_unlock(&head->mutex);
645 btrfs_put_delayed_ref(&head->node);
646 goto again;
647 }
648 ret = __add_delayed_refs(head, seq, &info_key,
649 &prefs_delayed);
650 if (ret) {
651 spin_unlock(&delayed_refs->lock);
652 goto out;
653 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100654 }
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100655 spin_unlock(&delayed_refs->lock);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100656 }
Jan Schmidt8da6d582011-11-23 18:55:04 +0100657
658 if (path->slots[0]) {
659 struct extent_buffer *leaf;
660 int slot;
661
662 leaf = path->nodes[0];
663 slot = path->slots[0] - 1;
664 btrfs_item_key_to_cpu(leaf, &key, slot);
665 if (key.objectid == bytenr &&
666 key.type == BTRFS_EXTENT_ITEM_KEY) {
667 ret = __add_inline_refs(fs_info, path, bytenr,
668 &info_key, &info_level, &prefs);
669 if (ret)
670 goto out;
671 ret = __add_keyed_refs(fs_info, path, bytenr, &info_key,
672 info_level, &prefs);
673 if (ret)
674 goto out;
675 }
676 }
677 btrfs_release_path(path);
678
679 /*
680 * when adding the delayed refs above, the info_key might not have
681 * been known yet. Go over the list and replace the missing keys
682 */
683 list_for_each_entry(ref, &prefs_delayed, list) {
684 if ((ref->key.offset | ref->key.type | ref->key.objectid) == 0)
685 memcpy(&ref->key, &info_key, sizeof(ref->key));
686 }
687 list_splice_init(&prefs_delayed, &prefs);
688
689 ret = __merge_refs(&prefs, 1);
690 if (ret)
691 goto out;
692
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +0100693 ret = __resolve_indirect_refs(fs_info, search_commit_root, &prefs);
Jan Schmidt8da6d582011-11-23 18:55:04 +0100694 if (ret)
695 goto out;
696
697 ret = __merge_refs(&prefs, 2);
698 if (ret)
699 goto out;
700
701 while (!list_empty(&prefs)) {
702 ref = list_first_entry(&prefs, struct __prelim_ref, list);
703 list_del(&ref->list);
704 if (ref->count < 0)
705 WARN_ON(1);
706 if (ref->count && ref->root_id && ref->parent == 0) {
707 /* no parent == root of tree */
708 ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS);
709 BUG_ON(ret < 0);
710 }
711 if (ref->count && ref->parent) {
712 ret = ulist_add(refs, ref->parent, 0, GFP_NOFS);
713 BUG_ON(ret < 0);
714 }
715 kfree(ref);
716 }
717
718out:
719 if (head)
720 mutex_unlock(&head->mutex);
721 btrfs_free_path(path);
722 while (!list_empty(&prefs)) {
723 ref = list_first_entry(&prefs, struct __prelim_ref, list);
724 list_del(&ref->list);
725 kfree(ref);
726 }
727 while (!list_empty(&prefs_delayed)) {
728 ref = list_first_entry(&prefs_delayed, struct __prelim_ref,
729 list);
730 list_del(&ref->list);
731 kfree(ref);
732 }
733
734 return ret;
735}
736
737/*
738 * Finds all leafs with a reference to the specified combination of bytenr and
739 * offset. key_list_head will point to a list of corresponding keys (caller must
740 * free each list element). The leafs will be stored in the leafs ulist, which
741 * must be freed with ulist_free.
742 *
743 * returns 0 on success, <0 on error
744 */
745static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans,
746 struct btrfs_fs_info *fs_info, u64 bytenr,
747 u64 num_bytes, u64 seq, struct ulist **leafs)
748{
749 struct ulist *tmp;
750 int ret;
751
752 tmp = ulist_alloc(GFP_NOFS);
753 if (!tmp)
754 return -ENOMEM;
755 *leafs = ulist_alloc(GFP_NOFS);
756 if (!*leafs) {
757 ulist_free(tmp);
758 return -ENOMEM;
759 }
760
761 ret = find_parent_nodes(trans, fs_info, bytenr, seq, *leafs, tmp);
762 ulist_free(tmp);
763
764 if (ret < 0 && ret != -ENOENT) {
765 ulist_free(*leafs);
766 return ret;
767 }
768
769 return 0;
770}
771
772/*
773 * walk all backrefs for a given extent to find all roots that reference this
774 * extent. Walking a backref means finding all extents that reference this
775 * extent and in turn walk the backrefs of those, too. Naturally this is a
776 * recursive process, but here it is implemented in an iterative fashion: We
777 * find all referencing extents for the extent in question and put them on a
778 * list. In turn, we find all referencing extents for those, further appending
779 * to the list. The way we iterate the list allows adding more elements after
780 * the current while iterating. The process stops when we reach the end of the
781 * list. Found roots are added to the roots list.
782 *
783 * returns 0 on success, < 0 on error.
784 */
785int btrfs_find_all_roots(struct btrfs_trans_handle *trans,
786 struct btrfs_fs_info *fs_info, u64 bytenr,
787 u64 num_bytes, u64 seq, struct ulist **roots)
788{
789 struct ulist *tmp;
790 struct ulist_node *node = NULL;
791 int ret;
792
793 tmp = ulist_alloc(GFP_NOFS);
794 if (!tmp)
795 return -ENOMEM;
796 *roots = ulist_alloc(GFP_NOFS);
797 if (!*roots) {
798 ulist_free(tmp);
799 return -ENOMEM;
800 }
801
802 while (1) {
803 ret = find_parent_nodes(trans, fs_info, bytenr, seq,
804 tmp, *roots);
805 if (ret < 0 && ret != -ENOENT) {
806 ulist_free(tmp);
807 ulist_free(*roots);
808 return ret;
809 }
810 node = ulist_next(tmp, node);
811 if (!node)
812 break;
813 bytenr = node->val;
814 }
815
816 ulist_free(tmp);
817 return 0;
818}
819
820
Jan Schmidta542ad12011-06-13 19:52:59 +0200821static int __inode_info(u64 inum, u64 ioff, u8 key_type,
822 struct btrfs_root *fs_root, struct btrfs_path *path,
823 struct btrfs_key *found_key)
824{
825 int ret;
826 struct btrfs_key key;
827 struct extent_buffer *eb;
828
829 key.type = key_type;
830 key.objectid = inum;
831 key.offset = ioff;
832
833 ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
834 if (ret < 0)
835 return ret;
836
837 eb = path->nodes[0];
838 if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
839 ret = btrfs_next_leaf(fs_root, path);
840 if (ret)
841 return ret;
842 eb = path->nodes[0];
843 }
844
845 btrfs_item_key_to_cpu(eb, found_key, path->slots[0]);
846 if (found_key->type != key.type || found_key->objectid != key.objectid)
847 return 1;
848
849 return 0;
850}
851
852/*
853 * this makes the path point to (inum INODE_ITEM ioff)
854 */
855int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
856 struct btrfs_path *path)
857{
858 struct btrfs_key key;
859 return __inode_info(inum, ioff, BTRFS_INODE_ITEM_KEY, fs_root, path,
860 &key);
861}
862
863static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
864 struct btrfs_path *path,
865 struct btrfs_key *found_key)
866{
867 return __inode_info(inum, ioff, BTRFS_INODE_REF_KEY, fs_root, path,
868 found_key);
869}
870
871/*
872 * this iterates to turn a btrfs_inode_ref into a full filesystem path. elements
873 * of the path are separated by '/' and the path is guaranteed to be
874 * 0-terminated. the path is only given within the current file system.
875 * Therefore, it never starts with a '/'. the caller is responsible to provide
876 * "size" bytes in "dest". the dest buffer will be filled backwards. finally,
877 * the start point of the resulting string is returned. this pointer is within
878 * dest, normally.
879 * in case the path buffer would overflow, the pointer is decremented further
880 * as if output was written to the buffer, though no more output is actually
881 * generated. that way, the caller can determine how much space would be
882 * required for the path to fit into the buffer. in that case, the returned
883 * value will be smaller than dest. callers must check this!
884 */
885static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
886 struct btrfs_inode_ref *iref,
887 struct extent_buffer *eb_in, u64 parent,
888 char *dest, u32 size)
889{
890 u32 len;
891 int slot;
892 u64 next_inum;
893 int ret;
894 s64 bytes_left = size - 1;
895 struct extent_buffer *eb = eb_in;
896 struct btrfs_key found_key;
Jan Schmidtb916a592012-04-13 12:28:08 +0200897 int leave_spinning = path->leave_spinning;
Jan Schmidta542ad12011-06-13 19:52:59 +0200898
899 if (bytes_left >= 0)
900 dest[bytes_left] = '\0';
901
Jan Schmidtb916a592012-04-13 12:28:08 +0200902 path->leave_spinning = 1;
Jan Schmidta542ad12011-06-13 19:52:59 +0200903 while (1) {
904 len = btrfs_inode_ref_name_len(eb, iref);
905 bytes_left -= len;
906 if (bytes_left >= 0)
907 read_extent_buffer(eb, dest + bytes_left,
908 (unsigned long)(iref + 1), len);
Jan Schmidtb916a592012-04-13 12:28:08 +0200909 if (eb != eb_in) {
910 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidta542ad12011-06-13 19:52:59 +0200911 free_extent_buffer(eb);
Jan Schmidtb916a592012-04-13 12:28:08 +0200912 }
Jan Schmidta542ad12011-06-13 19:52:59 +0200913 ret = inode_ref_info(parent, 0, fs_root, path, &found_key);
Jan Schmidt8f24b492012-02-08 16:01:01 +0100914 if (ret > 0)
915 ret = -ENOENT;
Jan Schmidta542ad12011-06-13 19:52:59 +0200916 if (ret)
917 break;
918 next_inum = found_key.offset;
919
920 /* regular exit ahead */
921 if (parent == next_inum)
922 break;
923
924 slot = path->slots[0];
925 eb = path->nodes[0];
926 /* make sure we can use eb after releasing the path */
Jan Schmidtb916a592012-04-13 12:28:08 +0200927 if (eb != eb_in) {
Jan Schmidta542ad12011-06-13 19:52:59 +0200928 atomic_inc(&eb->refs);
Jan Schmidtb916a592012-04-13 12:28:08 +0200929 btrfs_tree_read_lock(eb);
930 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
931 }
Jan Schmidta542ad12011-06-13 19:52:59 +0200932 btrfs_release_path(path);
933
934 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
935 parent = next_inum;
936 --bytes_left;
937 if (bytes_left >= 0)
938 dest[bytes_left] = '/';
939 }
940
941 btrfs_release_path(path);
Jan Schmidtb916a592012-04-13 12:28:08 +0200942 path->leave_spinning = leave_spinning;
Jan Schmidta542ad12011-06-13 19:52:59 +0200943
944 if (ret)
945 return ERR_PTR(ret);
946
947 return dest + bytes_left;
948}
949
950/*
951 * this makes the path point to (logical EXTENT_ITEM *)
952 * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for
953 * tree blocks and <0 on error.
954 */
955int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
956 struct btrfs_path *path, struct btrfs_key *found_key)
957{
958 int ret;
959 u64 flags;
960 u32 item_size;
961 struct extent_buffer *eb;
962 struct btrfs_extent_item *ei;
963 struct btrfs_key key;
964
965 key.type = BTRFS_EXTENT_ITEM_KEY;
966 key.objectid = logical;
967 key.offset = (u64)-1;
968
969 ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
970 if (ret < 0)
971 return ret;
972 ret = btrfs_previous_item(fs_info->extent_root, path,
973 0, BTRFS_EXTENT_ITEM_KEY);
974 if (ret < 0)
975 return ret;
976
977 btrfs_item_key_to_cpu(path->nodes[0], found_key, path->slots[0]);
978 if (found_key->type != BTRFS_EXTENT_ITEM_KEY ||
979 found_key->objectid > logical ||
Jan Schmidt4692cf52011-12-02 14:56:41 +0100980 found_key->objectid + found_key->offset <= logical) {
981 pr_debug("logical %llu is not within any extent\n",
982 (unsigned long long)logical);
Jan Schmidta542ad12011-06-13 19:52:59 +0200983 return -ENOENT;
Jan Schmidt4692cf52011-12-02 14:56:41 +0100984 }
Jan Schmidta542ad12011-06-13 19:52:59 +0200985
986 eb = path->nodes[0];
987 item_size = btrfs_item_size_nr(eb, path->slots[0]);
988 BUG_ON(item_size < sizeof(*ei));
989
990 ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
991 flags = btrfs_extent_flags(eb, ei);
992
Jan Schmidt4692cf52011-12-02 14:56:41 +0100993 pr_debug("logical %llu is at position %llu within the extent (%llu "
994 "EXTENT_ITEM %llu) flags %#llx size %u\n",
995 (unsigned long long)logical,
996 (unsigned long long)(logical - found_key->objectid),
997 (unsigned long long)found_key->objectid,
998 (unsigned long long)found_key->offset,
999 (unsigned long long)flags, item_size);
Jan Schmidta542ad12011-06-13 19:52:59 +02001000 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1001 return BTRFS_EXTENT_FLAG_TREE_BLOCK;
1002 if (flags & BTRFS_EXTENT_FLAG_DATA)
1003 return BTRFS_EXTENT_FLAG_DATA;
1004
1005 return -EIO;
1006}
1007
1008/*
1009 * helper function to iterate extent inline refs. ptr must point to a 0 value
1010 * for the first call and may be modified. it is used to track state.
1011 * if more refs exist, 0 is returned and the next call to
1012 * __get_extent_inline_ref must pass the modified ptr parameter to get the
1013 * next ref. after the last ref was processed, 1 is returned.
1014 * returns <0 on error
1015 */
1016static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb,
1017 struct btrfs_extent_item *ei, u32 item_size,
1018 struct btrfs_extent_inline_ref **out_eiref,
1019 int *out_type)
1020{
1021 unsigned long end;
1022 u64 flags;
1023 struct btrfs_tree_block_info *info;
1024
1025 if (!*ptr) {
1026 /* first call */
1027 flags = btrfs_extent_flags(eb, ei);
1028 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1029 info = (struct btrfs_tree_block_info *)(ei + 1);
1030 *out_eiref =
1031 (struct btrfs_extent_inline_ref *)(info + 1);
1032 } else {
1033 *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1);
1034 }
1035 *ptr = (unsigned long)*out_eiref;
1036 if ((void *)*ptr >= (void *)ei + item_size)
1037 return -ENOENT;
1038 }
1039
1040 end = (unsigned long)ei + item_size;
1041 *out_eiref = (struct btrfs_extent_inline_ref *)*ptr;
1042 *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref);
1043
1044 *ptr += btrfs_extent_inline_ref_size(*out_type);
1045 WARN_ON(*ptr > end);
1046 if (*ptr == end)
1047 return 1; /* last */
1048
1049 return 0;
1050}
1051
1052/*
1053 * reads the tree block backref for an extent. tree level and root are returned
1054 * through out_level and out_root. ptr must point to a 0 value for the first
1055 * call and may be modified (see __get_extent_inline_ref comment).
1056 * returns 0 if data was provided, 1 if there was no more data to provide or
1057 * <0 on error.
1058 */
1059int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb,
1060 struct btrfs_extent_item *ei, u32 item_size,
1061 u64 *out_root, u8 *out_level)
1062{
1063 int ret;
1064 int type;
1065 struct btrfs_tree_block_info *info;
1066 struct btrfs_extent_inline_ref *eiref;
1067
1068 if (*ptr == (unsigned long)-1)
1069 return 1;
1070
1071 while (1) {
1072 ret = __get_extent_inline_ref(ptr, eb, ei, item_size,
1073 &eiref, &type);
1074 if (ret < 0)
1075 return ret;
1076
1077 if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1078 type == BTRFS_SHARED_BLOCK_REF_KEY)
1079 break;
1080
1081 if (ret == 1)
1082 return 1;
1083 }
1084
1085 /* we can treat both ref types equally here */
1086 info = (struct btrfs_tree_block_info *)(ei + 1);
1087 *out_root = btrfs_extent_inline_ref_offset(eb, eiref);
1088 *out_level = btrfs_tree_block_level(eb, info);
1089
1090 if (ret == 1)
1091 *ptr = (unsigned long)-1;
1092
1093 return 0;
1094}
1095
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001096static int iterate_leaf_refs(struct btrfs_fs_info *fs_info, u64 logical,
Jan Schmidt4692cf52011-12-02 14:56:41 +01001097 u64 orig_extent_item_objectid,
1098 u64 extent_item_pos, u64 root,
1099 iterate_extent_inodes_t *iterate, void *ctx)
Jan Schmidta542ad12011-06-13 19:52:59 +02001100{
1101 u64 disk_byte;
1102 struct btrfs_key key;
1103 struct btrfs_file_extent_item *fi;
1104 struct extent_buffer *eb;
1105 int slot;
1106 int nritems;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001107 int ret = 0;
1108 int extent_type;
1109 u64 data_offset;
1110 u64 data_len;
Jan Schmidta542ad12011-06-13 19:52:59 +02001111
1112 eb = read_tree_block(fs_info->tree_root, logical,
1113 fs_info->tree_root->leafsize, 0);
1114 if (!eb)
1115 return -EIO;
1116
1117 /*
1118 * from the shared data ref, we only have the leaf but we need
1119 * the key. thus, we must look into all items and see that we
1120 * find one (some) with a reference to our extent item.
1121 */
1122 nritems = btrfs_header_nritems(eb);
1123 for (slot = 0; slot < nritems; ++slot) {
1124 btrfs_item_key_to_cpu(eb, &key, slot);
1125 if (key.type != BTRFS_EXTENT_DATA_KEY)
1126 continue;
1127 fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001128 extent_type = btrfs_file_extent_type(eb, fi);
1129 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
1130 continue;
1131 /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */
Jan Schmidta542ad12011-06-13 19:52:59 +02001132 disk_byte = btrfs_file_extent_disk_bytenr(eb, fi);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001133 if (disk_byte != orig_extent_item_objectid)
1134 continue;
Jan Schmidta542ad12011-06-13 19:52:59 +02001135
Jan Schmidt4692cf52011-12-02 14:56:41 +01001136 data_offset = btrfs_file_extent_offset(eb, fi);
1137 data_len = btrfs_file_extent_num_bytes(eb, fi);
1138
1139 if (extent_item_pos < data_offset ||
1140 extent_item_pos >= data_offset + data_len)
1141 continue;
1142
1143 pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), "
1144 "root %llu\n", orig_extent_item_objectid,
1145 key.objectid, key.offset, root);
1146 ret = iterate(key.objectid,
1147 key.offset + (extent_item_pos - data_offset),
1148 root, ctx);
1149 if (ret) {
1150 pr_debug("stopping iteration because ret=%d\n", ret);
1151 break;
1152 }
Jan Schmidta542ad12011-06-13 19:52:59 +02001153 }
1154
1155 free_extent_buffer(eb);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001156
Jan Schmidta542ad12011-06-13 19:52:59 +02001157 return ret;
1158}
1159
1160/*
1161 * calls iterate() for every inode that references the extent identified by
Jan Schmidt4692cf52011-12-02 14:56:41 +01001162 * the given parameters.
Jan Schmidta542ad12011-06-13 19:52:59 +02001163 * when the iterator function returns a non-zero value, iteration stops.
1164 */
1165int iterate_extent_inodes(struct btrfs_fs_info *fs_info,
Jan Schmidt4692cf52011-12-02 14:56:41 +01001166 u64 extent_item_objectid, u64 extent_item_pos,
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001167 int search_commit_root,
Jan Schmidta542ad12011-06-13 19:52:59 +02001168 iterate_extent_inodes_t *iterate, void *ctx)
1169{
Jan Schmidta542ad12011-06-13 19:52:59 +02001170 int ret;
Jan Schmidta542ad12011-06-13 19:52:59 +02001171 struct list_head data_refs = LIST_HEAD_INIT(data_refs);
1172 struct list_head shared_refs = LIST_HEAD_INIT(shared_refs);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001173 struct btrfs_trans_handle *trans;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001174 struct ulist *refs = NULL;
1175 struct ulist *roots = NULL;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001176 struct ulist_node *ref_node = NULL;
1177 struct ulist_node *root_node = NULL;
1178 struct seq_list seq_elem;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001179 struct btrfs_delayed_ref_root *delayed_refs = NULL;
Jan Schmidta542ad12011-06-13 19:52:59 +02001180
Jan Schmidt4692cf52011-12-02 14:56:41 +01001181 pr_debug("resolving all inodes for extent %llu\n",
1182 extent_item_objectid);
1183
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001184 if (search_commit_root) {
1185 trans = BTRFS_BACKREF_SEARCH_COMMIT_ROOT;
1186 } else {
1187 trans = btrfs_join_transaction(fs_info->extent_root);
1188 if (IS_ERR(trans))
1189 return PTR_ERR(trans);
1190
1191 delayed_refs = &trans->transaction->delayed_refs;
1192 spin_lock(&delayed_refs->lock);
1193 btrfs_get_delayed_seq(delayed_refs, &seq_elem);
1194 spin_unlock(&delayed_refs->lock);
1195 }
Jan Schmidt4692cf52011-12-02 14:56:41 +01001196
1197 ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid,
1198 extent_item_pos, seq_elem.seq,
1199 &refs);
1200
1201 if (ret)
1202 goto out;
1203
1204 while (!ret && (ref_node = ulist_next(refs, ref_node))) {
1205 ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, -1,
1206 seq_elem.seq, &roots);
1207 if (ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02001208 break;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001209 while (!ret && (root_node = ulist_next(roots, root_node))) {
1210 pr_debug("root %llu references leaf %llu\n",
1211 root_node->val, ref_node->val);
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001212 ret = iterate_leaf_refs(fs_info, ref_node->val,
Jan Schmidt4692cf52011-12-02 14:56:41 +01001213 extent_item_objectid,
1214 extent_item_pos, root_node->val,
1215 iterate, ctx);
Jan Schmidta542ad12011-06-13 19:52:59 +02001216 }
1217 }
1218
Jan Schmidt4692cf52011-12-02 14:56:41 +01001219 ulist_free(refs);
1220 ulist_free(roots);
1221out:
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001222 if (!search_commit_root) {
1223 btrfs_put_delayed_seq(delayed_refs, &seq_elem);
1224 btrfs_end_transaction(trans, fs_info->extent_root);
1225 }
1226
Jan Schmidta542ad12011-06-13 19:52:59 +02001227 return ret;
1228}
1229
1230int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info,
1231 struct btrfs_path *path,
1232 iterate_extent_inodes_t *iterate, void *ctx)
1233{
1234 int ret;
Jan Schmidt4692cf52011-12-02 14:56:41 +01001235 u64 extent_item_pos;
Jan Schmidta542ad12011-06-13 19:52:59 +02001236 struct btrfs_key found_key;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001237 int search_commit_root = path->search_commit_root;
Jan Schmidta542ad12011-06-13 19:52:59 +02001238
1239 ret = extent_from_logical(fs_info, logical, path,
1240 &found_key);
Jan Schmidt4692cf52011-12-02 14:56:41 +01001241 btrfs_release_path(path);
Jan Schmidta542ad12011-06-13 19:52:59 +02001242 if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1243 ret = -EINVAL;
1244 if (ret < 0)
1245 return ret;
1246
Jan Schmidt4692cf52011-12-02 14:56:41 +01001247 extent_item_pos = logical - found_key.objectid;
Jan Schmidt7a3ae2f2012-03-23 17:32:28 +01001248 ret = iterate_extent_inodes(fs_info, found_key.objectid,
1249 extent_item_pos, search_commit_root,
1250 iterate, ctx);
Jan Schmidta542ad12011-06-13 19:52:59 +02001251
1252 return ret;
1253}
1254
1255static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
1256 struct btrfs_path *path,
1257 iterate_irefs_t *iterate, void *ctx)
1258{
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02001259 int ret = 0;
Jan Schmidta542ad12011-06-13 19:52:59 +02001260 int slot;
1261 u32 cur;
1262 u32 len;
1263 u32 name_len;
1264 u64 parent = 0;
1265 int found = 0;
1266 struct extent_buffer *eb;
1267 struct btrfs_item *item;
1268 struct btrfs_inode_ref *iref;
1269 struct btrfs_key found_key;
1270
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02001271 while (!ret) {
Jan Schmidtb916a592012-04-13 12:28:08 +02001272 path->leave_spinning = 1;
Jan Schmidta542ad12011-06-13 19:52:59 +02001273 ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path,
1274 &found_key);
1275 if (ret < 0)
1276 break;
1277 if (ret) {
1278 ret = found ? 0 : -ENOENT;
1279 break;
1280 }
1281 ++found;
1282
1283 parent = found_key.offset;
1284 slot = path->slots[0];
1285 eb = path->nodes[0];
1286 /* make sure we can use eb after releasing the path */
1287 atomic_inc(&eb->refs);
Jan Schmidtb916a592012-04-13 12:28:08 +02001288 btrfs_tree_read_lock(eb);
1289 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
Jan Schmidta542ad12011-06-13 19:52:59 +02001290 btrfs_release_path(path);
1291
1292 item = btrfs_item_nr(eb, slot);
1293 iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
1294
1295 for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) {
1296 name_len = btrfs_inode_ref_name_len(eb, iref);
1297 /* path must be released before calling iterate()! */
Jan Schmidt4692cf52011-12-02 14:56:41 +01001298 pr_debug("following ref at offset %u for inode %llu in "
1299 "tree %llu\n", cur,
1300 (unsigned long long)found_key.objectid,
1301 (unsigned long long)fs_root->objectid);
Jan Schmidta542ad12011-06-13 19:52:59 +02001302 ret = iterate(parent, iref, eb, ctx);
Jan Schmidtaefc1eb2012-04-13 12:28:00 +02001303 if (ret)
Jan Schmidta542ad12011-06-13 19:52:59 +02001304 break;
Jan Schmidta542ad12011-06-13 19:52:59 +02001305 len = sizeof(*iref) + name_len;
1306 iref = (struct btrfs_inode_ref *)((char *)iref + len);
1307 }
Jan Schmidtb916a592012-04-13 12:28:08 +02001308 btrfs_tree_read_unlock_blocking(eb);
Jan Schmidta542ad12011-06-13 19:52:59 +02001309 free_extent_buffer(eb);
1310 }
1311
1312 btrfs_release_path(path);
1313
1314 return ret;
1315}
1316
1317/*
1318 * returns 0 if the path could be dumped (probably truncated)
1319 * returns <0 in case of an error
1320 */
1321static int inode_to_path(u64 inum, struct btrfs_inode_ref *iref,
1322 struct extent_buffer *eb, void *ctx)
1323{
1324 struct inode_fs_paths *ipath = ctx;
1325 char *fspath;
1326 char *fspath_min;
1327 int i = ipath->fspath->elem_cnt;
1328 const int s_ptr = sizeof(char *);
1329 u32 bytes_left;
1330
1331 bytes_left = ipath->fspath->bytes_left > s_ptr ?
1332 ipath->fspath->bytes_left - s_ptr : 0;
1333
Chris Mason740c3d22011-11-02 15:48:34 -04001334 fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
Jan Schmidta542ad12011-06-13 19:52:59 +02001335 fspath = iref_to_path(ipath->fs_root, ipath->btrfs_path, iref, eb,
1336 inum, fspath_min, bytes_left);
1337 if (IS_ERR(fspath))
1338 return PTR_ERR(fspath);
1339
1340 if (fspath > fspath_min) {
Jan Schmidt4692cf52011-12-02 14:56:41 +01001341 pr_debug("path resolved: %s\n", fspath);
Jeff Mahoney745c4d82011-11-20 07:31:57 -05001342 ipath->fspath->val[i] = (u64)(unsigned long)fspath;
Jan Schmidta542ad12011-06-13 19:52:59 +02001343 ++ipath->fspath->elem_cnt;
1344 ipath->fspath->bytes_left = fspath - fspath_min;
1345 } else {
Jan Schmidt4692cf52011-12-02 14:56:41 +01001346 pr_debug("missed path, not enough space. missing bytes: %lu, "
1347 "constructed so far: %s\n",
1348 (unsigned long)(fspath_min - fspath), fspath_min);
Jan Schmidta542ad12011-06-13 19:52:59 +02001349 ++ipath->fspath->elem_missed;
1350 ipath->fspath->bytes_missing += fspath_min - fspath;
1351 ipath->fspath->bytes_left = 0;
1352 }
1353
1354 return 0;
1355}
1356
1357/*
1358 * this dumps all file system paths to the inode into the ipath struct, provided
1359 * is has been created large enough. each path is zero-terminated and accessed
Chris Mason740c3d22011-11-02 15:48:34 -04001360 * from ipath->fspath->val[i].
Jan Schmidta542ad12011-06-13 19:52:59 +02001361 * when it returns, there are ipath->fspath->elem_cnt number of paths available
Chris Mason740c3d22011-11-02 15:48:34 -04001362 * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
Jan Schmidta542ad12011-06-13 19:52:59 +02001363 * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
1364 * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
1365 * have been needed to return all paths.
1366 */
1367int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
1368{
1369 return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
1370 inode_to_path, ipath);
1371}
1372
Jan Schmidta542ad12011-06-13 19:52:59 +02001373struct btrfs_data_container *init_data_container(u32 total_bytes)
1374{
1375 struct btrfs_data_container *data;
1376 size_t alloc_bytes;
1377
1378 alloc_bytes = max_t(size_t, total_bytes, sizeof(*data));
1379 data = kmalloc(alloc_bytes, GFP_NOFS);
1380 if (!data)
1381 return ERR_PTR(-ENOMEM);
1382
1383 if (total_bytes >= sizeof(*data)) {
1384 data->bytes_left = total_bytes - sizeof(*data);
1385 data->bytes_missing = 0;
1386 } else {
1387 data->bytes_missing = sizeof(*data) - total_bytes;
1388 data->bytes_left = 0;
1389 }
1390
1391 data->elem_cnt = 0;
1392 data->elem_missed = 0;
1393
1394 return data;
1395}
1396
1397/*
1398 * allocates space to return multiple file system paths for an inode.
1399 * total_bytes to allocate are passed, note that space usable for actual path
1400 * information will be total_bytes - sizeof(struct inode_fs_paths).
1401 * the returned pointer must be freed with free_ipath() in the end.
1402 */
1403struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root,
1404 struct btrfs_path *path)
1405{
1406 struct inode_fs_paths *ifp;
1407 struct btrfs_data_container *fspath;
1408
1409 fspath = init_data_container(total_bytes);
1410 if (IS_ERR(fspath))
1411 return (void *)fspath;
1412
1413 ifp = kmalloc(sizeof(*ifp), GFP_NOFS);
1414 if (!ifp) {
1415 kfree(fspath);
1416 return ERR_PTR(-ENOMEM);
1417 }
1418
1419 ifp->btrfs_path = path;
1420 ifp->fspath = fspath;
1421 ifp->fs_root = fs_root;
1422
1423 return ifp;
1424}
1425
1426void free_ipath(struct inode_fs_paths *ipath)
1427{
Jesper Juhl4735fb22012-04-12 22:47:52 +02001428 if (!ipath)
1429 return;
Ilya Dryomov5eb56d22012-03-27 17:09:18 +03001430 kfree(ipath->fspath);
Jan Schmidta542ad12011-06-13 19:52:59 +02001431 kfree(ipath);
1432}