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a542ad1b JS |
1 | /* |
2 | * Copyright (C) 2011 STRATO. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public | |
6 | * License v2 as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public | |
14 | * License along with this program; if not, write to the | |
15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
16 | * Boston, MA 021110-1307, USA. | |
17 | */ | |
18 | ||
19 | #include "ctree.h" | |
20 | #include "disk-io.h" | |
21 | #include "backref.h" | |
8da6d581 JS |
22 | #include "ulist.h" |
23 | #include "transaction.h" | |
24 | #include "delayed-ref.h" | |
b916a59a | 25 | #include "locking.h" |
a542ad1b | 26 | |
8da6d581 JS |
27 | /* |
28 | * this structure records all encountered refs on the way up to the root | |
29 | */ | |
30 | struct __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 | ||
40 | static 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 | ||
66 | static 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 | ||
77 | add_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 | */ | |
119 | static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, | |
7a3ae2f8 | 120 | int search_commit_root, |
8da6d581 JS |
121 | 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; | |
7a3ae2f8 | 136 | path->search_commit_root = !!search_commit_root; |
8da6d581 JS |
137 | |
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); | |
185 | out: | |
186 | btrfs_free_path(path); | |
187 | return ret; | |
188 | } | |
189 | ||
190 | /* | |
191 | * resolve all indirect backrefs from the list | |
192 | */ | |
193 | static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info, | |
7a3ae2f8 | 194 | int search_commit_root, |
8da6d581 JS |
195 | 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; | |
7a3ae2f8 JS |
219 | err = __resolve_indirect_ref(fs_info, search_commit_root, |
220 | ref, parents); | |
8da6d581 JS |
221 | 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 | */ | |
255 | static 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 | */ | |
298 | static 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; | |
b1375d64 | 305 | int ret = 0; |
8da6d581 JS |
306 | |
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 | */ | |
395 | static 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 | { | |
b1375d64 | 400 | int ret = 0; |
8da6d581 JS |
401 | 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 | */ | |
497 | static 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 | */ | |
583 | static 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; | |
d3b01064 | 591 | struct btrfs_delayed_ref_head *head; |
8da6d581 JS |
592 | int info_level = 0; |
593 | int ret; | |
7a3ae2f8 | 594 | int search_commit_root = (trans == BTRFS_BACKREF_SEARCH_COMMIT_ROOT); |
8da6d581 JS |
595 | 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; | |
7a3ae2f8 | 609 | path->search_commit_root = !!search_commit_root; |
8da6d581 JS |
610 | |
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 | */ | |
616 | again: | |
d3b01064 LZ |
617 | head = NULL; |
618 | ||
8da6d581 JS |
619 | 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 | ||
7a3ae2f8 JS |
624 | 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); | |
636 | ||
637 | btrfs_release_path(path); | |
638 | ||
639 | /* | |
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 | } | |
d3b01064 | 654 | } |
7a3ae2f8 | 655 | spin_unlock(&delayed_refs->lock); |
8da6d581 | 656 | } |
8da6d581 JS |
657 | |
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 | ||
7a3ae2f8 | 693 | ret = __resolve_indirect_refs(fs_info, search_commit_root, &prefs); |
8da6d581 JS |
694 | 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 | ||
718 | out: | |
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 | */ | |
745 | static 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 | */ | |
785 | int 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 | ||
a542ad1b JS |
821 | static 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 | */ | |
855 | int 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 | ||
863 | static 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 | */ | |
885 | static 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; | |
b916a59a | 897 | int leave_spinning = path->leave_spinning; |
a542ad1b JS |
898 | |
899 | if (bytes_left >= 0) | |
900 | dest[bytes_left] = '\0'; | |
901 | ||
b916a59a | 902 | path->leave_spinning = 1; |
a542ad1b JS |
903 | 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); | |
b916a59a JS |
909 | if (eb != eb_in) { |
910 | btrfs_tree_read_unlock_blocking(eb); | |
a542ad1b | 911 | free_extent_buffer(eb); |
b916a59a | 912 | } |
a542ad1b | 913 | ret = inode_ref_info(parent, 0, fs_root, path, &found_key); |
8f24b496 JS |
914 | if (ret > 0) |
915 | ret = -ENOENT; | |
a542ad1b JS |
916 | 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 */ | |
b916a59a | 927 | if (eb != eb_in) { |
a542ad1b | 928 | atomic_inc(&eb->refs); |
b916a59a JS |
929 | btrfs_tree_read_lock(eb); |
930 | btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); | |
931 | } | |
a542ad1b JS |
932 | 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); | |
b916a59a | 942 | path->leave_spinning = leave_spinning; |
a542ad1b JS |
943 | |
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 | */ | |
955 | int 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 || | |
4692cf58 JS |
980 | found_key->objectid + found_key->offset <= logical) { |
981 | pr_debug("logical %llu is not within any extent\n", | |
982 | (unsigned long long)logical); | |
a542ad1b | 983 | return -ENOENT; |
4692cf58 | 984 | } |
a542ad1b JS |
985 | |
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 | ||
4692cf58 JS |
993 | 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); | |
a542ad1b JS |
1000 | 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 | */ | |
1016 | static 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 | */ | |
1059 | int 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 | ||
7a3ae2f8 | 1096 | static int iterate_leaf_refs(struct btrfs_fs_info *fs_info, u64 logical, |
4692cf58 JS |
1097 | u64 orig_extent_item_objectid, |
1098 | u64 extent_item_pos, u64 root, | |
1099 | iterate_extent_inodes_t *iterate, void *ctx) | |
a542ad1b JS |
1100 | { |
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; | |
4692cf58 JS |
1107 | int ret = 0; |
1108 | int extent_type; | |
1109 | u64 data_offset; | |
1110 | u64 data_len; | |
a542ad1b JS |
1111 | |
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); | |
4692cf58 JS |
1128 | 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 */ | |
a542ad1b | 1132 | disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); |
4692cf58 JS |
1133 | if (disk_byte != orig_extent_item_objectid) |
1134 | continue; | |
a542ad1b | 1135 | |
4692cf58 JS |
1136 | 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 | } | |
a542ad1b JS |
1153 | } |
1154 | ||
1155 | free_extent_buffer(eb); | |
4692cf58 | 1156 | |
a542ad1b JS |
1157 | return ret; |
1158 | } | |
1159 | ||
1160 | /* | |
1161 | * calls iterate() for every inode that references the extent identified by | |
4692cf58 | 1162 | * the given parameters. |
a542ad1b JS |
1163 | * when the iterator function returns a non-zero value, iteration stops. |
1164 | */ | |
1165 | int iterate_extent_inodes(struct btrfs_fs_info *fs_info, | |
4692cf58 | 1166 | u64 extent_item_objectid, u64 extent_item_pos, |
7a3ae2f8 | 1167 | int search_commit_root, |
a542ad1b JS |
1168 | iterate_extent_inodes_t *iterate, void *ctx) |
1169 | { | |
a542ad1b | 1170 | int ret; |
a542ad1b JS |
1171 | struct list_head data_refs = LIST_HEAD_INIT(data_refs); |
1172 | struct list_head shared_refs = LIST_HEAD_INIT(shared_refs); | |
4692cf58 | 1173 | struct btrfs_trans_handle *trans; |
7a3ae2f8 JS |
1174 | struct ulist *refs = NULL; |
1175 | struct ulist *roots = NULL; | |
4692cf58 JS |
1176 | struct ulist_node *ref_node = NULL; |
1177 | struct ulist_node *root_node = NULL; | |
1178 | struct seq_list seq_elem; | |
7a3ae2f8 | 1179 | struct btrfs_delayed_ref_root *delayed_refs = NULL; |
a542ad1b | 1180 | |
4692cf58 JS |
1181 | pr_debug("resolving all inodes for extent %llu\n", |
1182 | extent_item_objectid); | |
a542ad1b | 1183 | |
7a3ae2f8 JS |
1184 | 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 | } | |
a542ad1b | 1196 | |
4692cf58 JS |
1197 | ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid, |
1198 | extent_item_pos, seq_elem.seq, | |
1199 | &refs); | |
a542ad1b | 1200 | |
4692cf58 JS |
1201 | if (ret) |
1202 | goto out; | |
a542ad1b | 1203 | |
4692cf58 JS |
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) | |
1208 | break; | |
1209 | 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); | |
7a3ae2f8 | 1212 | ret = iterate_leaf_refs(fs_info, ref_node->val, |
4692cf58 JS |
1213 | extent_item_objectid, |
1214 | extent_item_pos, root_node->val, | |
1215 | iterate, ctx); | |
1216 | } | |
a542ad1b JS |
1217 | } |
1218 | ||
4692cf58 JS |
1219 | ulist_free(refs); |
1220 | ulist_free(roots); | |
1221 | out: | |
7a3ae2f8 JS |
1222 | if (!search_commit_root) { |
1223 | btrfs_put_delayed_seq(delayed_refs, &seq_elem); | |
1224 | btrfs_end_transaction(trans, fs_info->extent_root); | |
1225 | } | |
1226 | ||
a542ad1b JS |
1227 | return ret; |
1228 | } | |
1229 | ||
1230 | int 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; | |
4692cf58 | 1235 | u64 extent_item_pos; |
a542ad1b | 1236 | struct btrfs_key found_key; |
7a3ae2f8 | 1237 | int search_commit_root = path->search_commit_root; |
a542ad1b JS |
1238 | |
1239 | ret = extent_from_logical(fs_info, logical, path, | |
1240 | &found_key); | |
4692cf58 | 1241 | btrfs_release_path(path); |
a542ad1b JS |
1242 | if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) |
1243 | ret = -EINVAL; | |
1244 | if (ret < 0) | |
1245 | return ret; | |
1246 | ||
4692cf58 | 1247 | extent_item_pos = logical - found_key.objectid; |
7a3ae2f8 JS |
1248 | ret = iterate_extent_inodes(fs_info, found_key.objectid, |
1249 | extent_item_pos, search_commit_root, | |
1250 | iterate, ctx); | |
a542ad1b JS |
1251 | |
1252 | return ret; | |
1253 | } | |
1254 | ||
1255 | static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, | |
1256 | struct btrfs_path *path, | |
1257 | iterate_irefs_t *iterate, void *ctx) | |
1258 | { | |
aefc1eb1 | 1259 | int ret = 0; |
a542ad1b JS |
1260 | 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 | ||
aefc1eb1 | 1271 | while (!ret) { |
b916a59a | 1272 | path->leave_spinning = 1; |
a542ad1b JS |
1273 | 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); | |
b916a59a JS |
1288 | btrfs_tree_read_lock(eb); |
1289 | btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); | |
a542ad1b JS |
1290 | 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()! */ | |
4692cf58 JS |
1298 | 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); | |
a542ad1b | 1302 | ret = iterate(parent, iref, eb, ctx); |
aefc1eb1 | 1303 | if (ret) |
a542ad1b | 1304 | break; |
a542ad1b JS |
1305 | len = sizeof(*iref) + name_len; |
1306 | iref = (struct btrfs_inode_ref *)((char *)iref + len); | |
1307 | } | |
b916a59a | 1308 | btrfs_tree_read_unlock_blocking(eb); |
a542ad1b JS |
1309 | 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 | */ | |
1321 | static 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 | ||
740c3d22 | 1334 | fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr; |
a542ad1b JS |
1335 | 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) { | |
4692cf58 | 1341 | pr_debug("path resolved: %s\n", fspath); |
745c4d8e | 1342 | ipath->fspath->val[i] = (u64)(unsigned long)fspath; |
a542ad1b JS |
1343 | ++ipath->fspath->elem_cnt; |
1344 | ipath->fspath->bytes_left = fspath - fspath_min; | |
1345 | } else { | |
4692cf58 JS |
1346 | pr_debug("missed path, not enough space. missing bytes: %lu, " |
1347 | "constructed so far: %s\n", | |
1348 | (unsigned long)(fspath_min - fspath), fspath_min); | |
a542ad1b JS |
1349 | ++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 | |
740c3d22 | 1360 | * from ipath->fspath->val[i]. |
a542ad1b | 1361 | * when it returns, there are ipath->fspath->elem_cnt number of paths available |
740c3d22 | 1362 | * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the |
a542ad1b JS |
1363 | * 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 | */ | |
1367 | int 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 | ||
a542ad1b JS |
1373 | struct 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 | */ | |
1403 | struct 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 | ||
1426 | void free_ipath(struct inode_fs_paths *ipath) | |
1427 | { | |
4735fb28 JJ |
1428 | if (!ipath) |
1429 | return; | |
5eb56d25 | 1430 | kfree(ipath->fspath); |
a542ad1b JS |
1431 | kfree(ipath); |
1432 | } |